GITAM DENTAL COLLEGE & HOSPITAL

DEPARTMENT OF

Oral & Maxillofacial Surgery

SEMINAR

On

Orthognathic Surgery – Midface procedures

Presented By:

Dr. Satyajit Sahu

III MDS

Orthognathic Surgery – Midface procedures

Introduction

Orthognathic surgery has evolved over many years to correct both facial deformity and oral dysfunction. Facial beauty is difficult to define in precise terms because subtle differences between individuals can produce marked aesthetic contrasts. Furthermore, different racial forms of beauty are not comparable and so ethnic norms are required to correct the abnormality. Despite this skeletal abnormality is recognisable, measurable, and usually correctable by orthognathic surgery.

Orthognathic surgery started as "Orthodontic surgery’ as an aid to orthodontics, later graduated to orthognathic surgery as a remedial measure to orthodontic limitations.

Orthognathic surgery is mainly directed at the correction of basal bone defects. The aim is to attain aesthetic, psychological and functional rehabilitation of the patient. However fine tooth movements for the optimum results are difficult to obtain with orthognathic surgery alone. Such finer adjustments can be achieved by orthodontics. Orthognathic surgery along with rhinoplasty and orthodontics can rehabilitate patients with facial deformities and oral dysfunction.

Historical events

Hullihen was the first person to correct jaw deformity surgically in 1849, when he corrected an anterior open bite by mandibular subapical osteotomy. Orthognathic surgery of the maxilla was first described in 1859 by Von Langenbeck for the removal of nasopharyngeal polyps. Cheever 1867 reported a maxillary osteotomy for complete

nasal obstruction secondary to epistaxis, he used a right hemimaxillary down fracture. Later many maxillary osteotomy techniques were described for the treatment of pathological process.

Blair in the early 1900’s was the first to classify jaw deformity into five classes as : Mandibular prognathism, Mandibular retrognathism, Alveolar mandibular protrusion, Alveolar maxillary protrusion and open bite.

In 1901, Le Fort published his classic description of the natural planes of maxillary fracture. Cohn-stock 1921 described segmental osteotomy of maxilla which was modified by Wassmund (1926) by a labial approach. Cupar 1954, Kole 1959 and Wunderer 1963 reported a direct surgical access to these procedures which improved mobilisation and maintained blood supply. Wassmund (1927) described a total horizontal maxillary osteotomy to close a posterior open bite and this constitute earliest work of Le fort I surgery. Axhausen (1934) performed the first total mobilisation of the maxilla.

Posterior segmentalization of the maxilla was first used by Schuchardt 1959 for correction of open bite. This had limited stability owing to its incomplete mobilisation. Kufner 1970 improved on this technique by completely mobilising the osteotomized segment prior to repositioning.

Paceno (1922) published some basic principles of roentgenographic cephalometry which was later modified and popularised by Broadbent and Holfrath (1935). Down (1945) put forward some standard measurements which helped the diagnosis of deformities of midface. Burstone et al 1978 & 1980 gave an analysis for the assessment of dentofacial

deformity using cephalometric radiographs " The cephalometric analysis for Orthognathic surgery" (COGS).

Use of bone grafts in midface surgical advancement were reported by Rowe (1954), Cernea and associates (1955), Lerinac (1958).

Separation of the pterygomaxillary junction was first advocated by Schuchardt in 1942. Moore and Ward 1949 recommended horizontal transection of the pterygoid plates for advancement. This technique was associated with severe bleeding so Wilmar advocated the pterygomaxillary disjunction technique for Le fort I osteotomy.

A combined form of anterior and posterior subapical osteotomies "total subapical maxillary osteotomy" were reported by Paul 1969 for midface hypoplasia.. This technique was further described by West & Epker 1972, Hall & Roddy 1975, Wolford & Epker 1975, West and McNeil 1975 and Hall & West 1976. Maloney (1982) reviewed this technique and described it as a good technique during his time. This technique is hardly in use now.

Hugo Obwegesser 1965 advocated complete mobilisation of maxilla so that maxilla could be repositioned without tension. This aided in stabilisation which was documented by Haller, Hogemann & Wilmar and Perko.

Hugo Obwegesser 1969 described a high quadrangular Le Fort I osteotomy for midface deficiency correction. This technique was later named as Quadrangular Le Fort I osteotomy by Keller & Sather 1989.

Converse & Colleagues in 1970 described an osteotomy at Le Fort II level but this had several biologic and anatomical

flaws so this technique did not have appreciation later. Henderson & Jackson 1973 described a classic Le Fort II osteotomy for correction of midface deficiency.

Kufner 1971 described an osteotomy procedure for midface deficiency correction, which was named as quadrangular Le fort II osteotomy by Steinhäuser 1980. This technique was modified by Stoleinga & Brown in 1996 which prevents damage to infra orbital nerve.

Vascular supply of lower maxilla and alveolar portion was extensively studied by Bell and Levi (1971) and Bell et al (1979). They concluded that the vitality of segment will not be affected if either palatal or buccal flaps were retained undisturbed.

Epker and Woodford 1980 gave a detailed down fracture technique for Le fort I maxillary osteotomy based on palatal flap. They advocated the use of same for anterior maxillary segment 0steotomy.

Sir Harold Gillies & Harrison 1950 performed Le Fort III osteotomy for midface deficiency.

Paul Tessier 1967 described various techniques for correction of orbito-craniofacial deformities.

The first use of bone plating was carried out by Soerensen in 1917 for fracture mandible. Bernd Spiessl 1974 was the first to use rigid fixation after sagittal split osteotomy. Use of rigid fixation to stabilise osteotomised segment was reported by Champy & associates 1976, Mischelet, Leyoness & Desus 1973, Dromer and Luhr 1981, Steinhäuser 1986 etc. Miniaturised plates were used by Luhr 1981, Steinhäuser 1986 etc. Miniaturised plates by Luhr,

1989 solved the problem of excessive bulk of miniplates for use in midface.

The latest developments in orthognathic surgery is the use of adjutant plastic surgical procedures like blepharoplasty, rhinoplasty, rhitidectomy, liposuction , lip correction and the use of the principle of distraction osteogenesis for correction of jaw deformities.

Anatomy of midface

The skeleton of midface is made up of intricate attachment of various bones, these include two maxilla, two nasal bones, two palatine bones, two zygoma and their temporal process, two inferior nasal conchae, the vomer, the ethmoid and the pterygoid process of the sphenoid bones. The articulation of these bones give the projection to midface. Any excess or deficiency in this region produces an unaesthetic deformity.

The midface is in relation to important aesthetic and functional landmarks such as the orbit, nasal cavity, maxillary sinus and the oral cavity.

The maxilla is a paired bone of the upper jaw, fused to form one central focus of the midface. It acts as a base for containing the teeth, support for nasal cartilages, gives attachments to muscles and forms the major bony plate for palate and orbit. Each hemimaxilla contain a large pyramidal shaped body, the maxillary sinus and four prominent process – the frontal, alveolar, zygomatic and palatine process. The body of maxilla is hollow and contains the maxillary sinus. The infero lateral walls of the maxilla are thinner and are directed in a angular fashion with narrower bottom and

gradually increasing in size superiorly. So an osteotomy cut in this area would result in telescoping of the inferior segment into the antrum and resulting in instability. The frontal process arises from the anteromedial corner of the body of maxilla and it articulates with nasal bone, frontal bones to form the medial wall of the orbit. The zygomatic process of the maxilla arises from the anterolateral corner of the maxilla and articulates with zygoma laterally. They together form the floor and lateral wall of the orbit. The highly vascular nasal mucosa is loosely attached to the rim of the pyriform ring of the maxilla. This can be easily raised from the palatine process of the maxilla. The infraorbital nerve and vessels pass through the infraorbital foramen which lies at the anterior surface of the maxilla below the infraorbital rim. A damage to this nerve is most likely in Le fort II and III procedures and this would produce profound paresthesia / anaesthesia of the upper lip and part of nose.

The zygoma is a paired bone and makes up the essence of the cheek prominence. It is diamond shaped bone. Its deficiency along with infraorbital deficiency would result in increased visibility of sclera. This has four process by which it attaches to frontal bone, maxilla and temporal bone.

Nasal bones are rectangular and articulate with frontal bone and process of frontal and maxilla. This gives the anatomic projection to the nasal bridge.

Palatine bones are paired bones which connect the maxilla with the sphenoid bone through pterygoid plates. It has a body and two process the horizontal and vertical. The greater and lesser palatine nerves and vessels pass through this bone. Posteriorly this bone articulates with pterygoid

plates. This articulation is disjuncted during total maxillary osteotomies when maxilla is to be advanced or impacted superiorly.

The inferior nasal concha is a paired bone that form the bony support of the inferior turbinates bilaterally. In some instances this might be enlarged which makes superior impaction of maxilla difficult.

Biological basis for maxillary osteotomies.

The delivery of an adequate amount of blood to the tissue capillaries for normal function of the organ is the primary purpose of the vascular system. Successful transportation of the maxillary dento-osseous segments by Le fort I osteotomy depends on preserving the vitality of the segment by proper design of the soft tissue and bone cuts.

Extensive studies on the blood supply of maxilla by Bell & Levy 1969 and others have shown an extensive anastomosis between the terminal branches of the maxillary vessels. This allows a wide range of buccal and palatal flaps to be raised. Formerly tunnelling procedures have been used to maintain a dual supply from the tissues of the cheek and palatal vessels. Studies by Bell & Levy 1969 have shown that interruption of these, for example the palatine vessels, will not lead to necrosis of bony segments, provided adequate buccolabial periosteal flaps retained.

Maxilla receives its blood supply from branches of maxillary artery – the palatine artery and superior alveolar arteries. It also receives collateral supply from the branches of facial artery. The collateral circulation within the maxilla and its evolving soft tissues and the many vascular

anastomosis in the maxilla, permit numerous technical modifications of the Le fort I osteotomy.

You et al 1991 studied the vasculature of the maxilla. He stated that

1. normal blood supply of the maxilla originates centrifugally from the alveolar medullary arterial system.

2. The mucoperiosteal arterial system also gives off many branches that penetrate the cortical bone and supply the maxilla.

3. The vascular connections between the maxilla and the surrounding soft tissues consist of not only the capillaries but also arteries and veins.

These multiple source of blood supply to the maxilla and abundant vascular communications between the hard and soft tissues constitute the biological foundation for maintaining dento-osseous viability despite transection of the medullary blood supply after maxillary osteotomies.

So for anterior maxillary osteotomy when a labial mucoperiosteal flap is reflected , the collateral circulation is from the palatal vessels, care has to be taken not to damage the palatal vessels. When a palatal mucoperiosteal flap is raised for osteotomy then the labial vessels has to be preserved.

Bell 1969, Bell & levy 1971 have demonstrated the viability of large or small segments of the maxilla when vascular pedicles from the palatal, facial or both mucosal surfaces were not detached from the osteotomised

segments. They also observed that ligation of the greater palatine arteries bilaterally did not adversely affect the outcome of the surgery when adequate palatal mucosa and labiobuccal gingival pedicles were maintained.

Azaz & Shteyer 1977 and Westwood & Tilson 1975 observed that the most common complication in surgery with multiple segments is the loss or devitalization of an occasional tooth adjacent to the interradicular osteotomy site.

Studies by Justin et al 2001 has shown that there is a hyper-vascularity in the pulpal and gingival tissue during healing ( 2nd –3rd week) after maxillary osteotomies.

Timing of surgery

As a rule of thumb it is better to wait till the skeletal growth is completed before doing orthognathic surgery. There has been report in literature to support the corrective surgical measure even during the growth period, specially if there is compelling psychological need for such intervention in the patient.

Maxillary growth usually ceases 2 years before mandibular growth completion but there is a difference of 6 years in late maturers. Post menarche growth of maxilla is negligible. Radius epiphyseal fusion is a definite indicator of completion of maxillary growth.

Surgical correction for maxillary excess is not contraindicated during growth period as reduction in growth of maxilla helps in the surgical measure for the patient.

Surgical approach to Midface.

Surgical treatment of dentofacial deformity was not undertaken until the beginning of the twentieth century due to difficulties in access to facial bones and the problems of anaesthesia.

Early surgeries were directed towards mandible mainly through the extra oral approach which had the disadvantage of visible scar. The maxillary procedures were initially linked to the management of cleft problems. Wasmund 1935, Axhausen 1937 & 1939 and Schuchardt 1942 developed approaches initially to anterior maxilla and later to posterior and whole maxilla.

Requirements of approach to facial bones.

There are number of prerequisites for approach to facial bones, these include.

1. This must be a safe approach which allows a clear view for placement of bone cuts and gives a good access for instruments.

2. While placing incisions thought must be given to possible problems such as proximity to vital structures, scarring and infection.

The important structures include large vessels and nerves like facial nerve and vessels, infra orbital nerves and mental nerve, nasolacrimal duct, canthal ligaments, external auditory canal etc.

The access to the facial bones can be broadly classified into two categories : transcutaneous and intraoral.

The best access is through skin but this leaves a visible scar. The skin incisions should be placed in such a way that it is hidden or follow natural skin creases.

The intraoral approach avoids scarring but it provides relatively poor visibility and access difficulties. Often special instruments are required with this technique.

Extra oral approaches to midface.

Le fort I osteotomy is approached entirely through the intraoral approach, while Le fort II and Le fort III might require incisions around the orbit. These incisions are to be placed in such a way that it minimises scarring and also does not effect functional limitations. A variety of incision have been used for accessing midface. These include.

1. Trans conjunctival incision.

2. Medial canthal incision.

3. Infra orbital incision.

4. Blepharoplasty incision.

5. Extended eyebrow incision.

6. Bicoronal incision.

7. Incisions to approach naso-orbit area.Trans conjunctival incision

This incision is used when access to the infra orbital region is needed during Le fort II and III osteotomies.

Here the incision is placed in the inferior fornix. Care is taken to avoid damage to lower lid tarsal plate and also to

cornea. Cornea is protected by suturing the upper edge of conjunctival incision to the upper lid margin during the operative procedure. Blunt dissection down exposes the periosteum on the orbital floor which is incised at the infra orbital rim.

A fine catgut is used to close conjunctival incision.Medial canthal incision

This incision is required to provide access to the bridge of the nose and medial orbital area during Le fort III osteotomy. This incision can be extended laterally for greater access to lateral infra orbital region.

The incision is made from a point just superior and medial to medial canthus to approximately midpoint between the lacrimal duct and infra orbital nerve. The incision passes through skin and superficial fascia, splitting orbicularis oculi onto the periosteum. This provides access to the anterior maxilla medial to the infra orbital nerve and also to nasal bones. The periosteum is stripped from over the infra orbital margin and along the floor of the orbit around and behind the nasolacrimal duct. Periosteum is also stripped from the nasal bones superior to medial canthal ligament.

Visible scarring is minimal with this type of incision but when incision is extended laterally below the infra orbital region it produces a visible scar.Blepharoplasty incision

This incision is used for accessing the malar region and also for naso orbital procedures in Le fort III osteotomy. This incision is more aesthetic than infra orbital incision.

Here the incision is made in the skin 1 – 2 mm below the grey line at the lid margin. The skin is undermined superficial to the orbicularis oculi muscle which is then split at the infra orbital margin. Dissection is done while taking care to prevent damage to the orbital septum. The periosteum over the maxilla is divided 1 to 2 mm below the infra orbital margin. By this approach antromedial malar osteotomy cuts can be placed. When a wider exposure is required the incision is extended laterally through crow’s foot crease.

The incision is closed in layers, first the periosteum, the muscle and finally the skin with fine subcuticular nylon sutures.Extended eyebrow incision

This approach is for access to lateral orbit .

The incision is made through the lateral part of the eyebrow and along its length parallel to hair follicles. This should not be extended beyond lateral canthus as it produces a visible scar. This incision provides good access to the frontozygomatic suture and allows for bony cuts to be placed through the lateral orbital wall down to the inferior orbital fissure. The incision is placed through the skin, superficial fascia, orbicularis oculi and deep fascia down to periosteum. The periosteum is incised at the anterolateral aspect of orbital margin. Bleeding is profuse which is controlled by diathermy.

Wound closure is done in layers.Naso orbital area exposure

Exposure of this area is difficult.

The midline vertical incision down the nose provides access to both the medial canthus area, but often leaves a persistent scar.

A horizontal or inverted ‘V’ cut extended from two canthal ligament again has the scar visibility. For approach to upper nasoethmoid area a horizontal incision from one eyebrow to other is preferred. For nasal lengthening procedures as along with Le fort II an inverted ‘V’ or ‘Y’ incision is preferred. Tension in the suture area is to be avoided as it is likely to spread the scar.

For Le fort III the approach to the whole of this area is best by a bicoronal incision.Bicoronal incision

The bicoronal ( bitemporal, bifrontal ) flap probably provides the best access to the upper face. It is essentially a continuation of the preauricular incision which is carried superiorly across the scalp. In the midline the incision is directed slightly anteriorly to allow for easier closure and for easy mobilisation of soft tissues. It must remain within the hairline particularly in males. In children this incision should not be brought forward as the scar tends to drift anteriorly as the child grows.

The incision is first marked and it is made through the skin, superficial fascia and galea. The line of separation is obtained in the loose areolar tissue above the pericranium. Dissection is done anteriorly and inferiorly in a plane temporalis fascia and pericranium. Approximately 2 cm above the orbits the pericranium is incised in a curved fashion forward from one orbital margin to another and this is

stripped off with the anterior flap. This flap is reflected over the bridge of the nose to expose the frontonasal suture, the supra orbital rims and lateral orbital margins. Further exposure is gained through a vertical incision through the periosteum overlying the bridge of the nose. The supra orbital neurovascular bundles are preserved and freed whenever necessary by cutting a foramina with a small chisel.

For Le fort III osteotomy the soft tissues incision is extended down to the zygomatic arch by incising the periosteum on the temporal surface of the orbit and the temporalis muscle retracted posterolatrally to expose the medial wall of the malar bone. The periosteum is raised along the orbital margin from the lateral, medial and superior walls. By this approach the whole of orbit, malar and frontonasal suture are exposed. It also gives good access to temporomadibular joint and nasoethmoid complex region. To avoid excessive bleeding, it is important to maintain a good hemostasis with the use of Raney clips along the flap margins.

After the operations are completed the scalp flap is replaced and the wound closed in layers with two scalp suction drain in place. Pressure dressing are given to avoid haematoma formation.

The intraoral approach

The great majority of the maxillary procedures are performed through an intraoral approach. Scars in the midface are to be avoided if at all possible as they cannot be hidden well and are usually unnecessary. Majority of Le fort I

osteotomies and segmental osteotomies of Maxilla are done through an intraoral incision.

Extensive anastomosis between the terminal branches of the maxillary vessels allows for a wide range of buccal and palatal flaps to be raised. Formerly tunnelling procedures have been used to maintain a dual supply from the tissues of the cheek and palatal vessels. Now osteotomy of maxilla is done based on the palatine vessels or on the labial / buccal vessels. Incisions for Le fort I osteotomy

The incisions used for Le fort I osteotomies include

1. Tunnelling approach

2. Down fracture approach

3. Approach in the cleft patient : Henderson – Jackson

4. Approach in the cleft patient : Converse – wake.

Tunnelling approach:

This type of incision was used during 1950 – 1970s. Here Le fort I osteotomy is done through three incisions. Here a horizontal incision is placed in the vestibule of first molar region bilaterally and a third incision is placed vertically in the midline anteriorly. The anterolateral wall of maxilla is sectioned through the lateral incisions. The nasal septum is detached through the midline incisions. The lateral nasal wall is fractured through midline incision using Rowe’s disimpaction forceps. This causes tearing of nasal mucosa. By this approach limited repositioning is only feasible due to poor accessibility.

Down fracture approach :

This technique developed by Bell 1975 has changed the approach to maxilla, aiding in positioning maxilla in all the planes and cutting the maxilla into varying pieces without risk of loss of segment. This procedure can be done under direct vision with less blood loss. Here the incision is made high in the maxillary vestibule from one second molar region to other lying just above the buccal/ labial attached gingiva. The mucoperiosteum is raised over the superior maxilla, round the pyriform aperture, the malars and the infra orbital area. Only minimal periosteal stripping is done in the dentoalveolar region in cases of adjutant segmental osteotomies. The nasal mucoperiosteum is raised along the floor of the mouth which helps in detaching nasal septum and also perform lateral nasal osteotomy cuts without tearing nasal mucosa.

Approaches in cleft lip & Palate:

Henderson and Jackson 1975 devised a useful approach for the management of maxillary hypoplasia in cleft lip case. They advocated splitting the lip through to the cleft line and then extending this incision into the labial sulcus on either side. To close the fistula, a buccal flap is reflected from the lesser segment side and it is rotated into the cleft alveolus to provide closure to the oral layer. The nasal floor mucoperiosteum is raised from the septum and lateral wall of the nose and closed under direct vision. Sometimes mobilisation of palatal tissues is necessary to close the palatal cleft.

To overcome the problem of palatopharyngeal scaring and the resultant velopharyngeal insufficiency Wake 1975

modified the Converse approach to Le fort I osteotomy by leaving behind the palatal tissues. Here vertical incisions right angle to the dental arch are placed anteriorly in the midline and laterally in the buccal vestibule molar/ premolar region. By tunnelling approach maxillary osteotomy is completed. A palatal flap is raised a few millimetres from the gingiva with the palatine vessels contained in it. The palatal flaps are raised up to the greater palatine canal. The posterior osteotomy cuts are placed anterior to the greater palatine canal and the maxilla is positioned anteriorly leaving behind the palatal flap. The anterior raw area is allowed to granulate secondarily. This approach diminishes the risk of speech changes but it is a difficult procedure and the osteotomy sites takes longer period to unite. Incisions for segmental procedures

Segmental osteotomies are done on the maxilla, these include the anterior maxillary osteotomy and posterior maxillary osteotomy.

The approaches used for anterior maxillary osteotomy are

1. Wassmund’s approach

2. Wunderer’s approach

3. Down fracture approach (Bell down fracture modification of the Cupar technique).

The posterior maxillary osteotomy is approached by

1. Buccal approach ( Kufner).

2. Buccal & Palatal approach ( Perko – Bell).

Approaches to anterior maxilla

Wassmund approach

The Wassmund approach relies on the buccolabial vascular pedicles and usually an intact palatal blood supply. An anterior median vertical and buccal vertical incisions are made. Buccal bone is removed through the buccal vertical incision up to the pyriform aperture by tunnelling approach. Palatal bone is removed by tunnelling approach under the mucoperiosteum from the socket area. Sometimes a small midline palatal incision aids removal of palatal bone. The nasal septum is approached through the anterior vertical incision. By this approach it is difficult to raise the maxilla and to setback posteriorly.

Wunderer approach

In the Wunderer approach, a transverse incision is placed across the hard palate in addition to the three vertical incisions described by Wassmund’s technique. This allows better access to the palate for major posterior movements. The transverse palatal incision is arched forward so that the suture will lie on the anterior palatal bone. The buccal bone and septum is approached through the vertical incisions as in Wassmund’s approach. The anterior segment is hinged on its labial pedicles.

Down fracture approach

The down fracture approach is the most widely used procedure for anterior maxillary osteotomy as this provides good access and also reliable blood supply. Here a vestibular

incision is placed in the labial vestibule. The buccal osteotomy cuts are done through tunnelling approach. The nasal mucosa is raised and the nasal septum detached through the vestibular incision. Any midline splitting is done before the completion of segmental osteotomy.

Approach to posterior maxilla

The approach to posterior maxilla, usually for raising the buccal segment, may be through the buccal and palatal mucoperiosteal incisions.

Kufner 1970 described a single buccal incision approach. This approach is difficult in flat palate and when antral walls are thick. The buccal bones are cut through the buccal incision and the vertical cut in the premolar region is done through the tunnelling approach. The palatine bone is cut by using a fine curved osteotome. When a palatine incision is planned it should be made medial to the palatine foramen and the osteotomy is performed lateral to the foramen.

When the palate is very flat the Perko – Bell technique (1967) may be adopted. Here both walls of the antrum are cut through the buccal approach. A parasagittal incision is made in the palate from premolar area to the junction of the hard and soft palate and the alveolar bone exposed and cut medially to the greater palatine foramen in an anteroposterior direction.

Besides these, a variety of techniques have been described to deal with individual problems in maxilla. It is best to choose the safest and most reliable one for the situation.

Osteotomy techniques – Maxilla.

A variety of osteotomy techniques have been described to correct the midface problems. The osteotomy techniques include either a segmental osteotomy of maxilla where a part of the maxilla is osteotomised and repositioned or total maxillary osteotomy is done at Le fort I, II, or III level to correct the deformity.

Segmental surgeries of Maxilla

The types of segmental osteotomies described for maxillary procedure include – single tooth osteotomy , anterior maxillary osteotomy and posterior maxillary osteotomy.Single tooth Osteotomies

Indication

1. The procedure is mostly used for dilacerated teeth

2. Those teeth that have been impacted into the alveolar bone following trauma.

3. Occasionally when more than one tooth requires repositioning.

Procedure

This procedure is limited to maxillary anterior tooth. This procedure requires good amount of inter radicular bone. The approach to single tooth Osteotomy is through either a small high horizontal labial sulcus incision or alternatively through two vertical incisions on either side of the tooth.

When using two vertical incisions, these are made through the mucoperiosteum a millimetre or two on either side of the proposed bone cut. The incision starts high in the labial sulcus and stops 2 –3 mm from the alveolar crest. Mucoperiosteum is not elevated over the tooth that is to be repositioned. Labial bone cut in made with fine burr, in the centre of inter-radicular area parallel to each other. High in the labial sulcus the mucoperiosteum is elevated ( tunnelled ) above the root apex of the tooth to be moved so that a horizontal cut may be made at least above the apex. The segment is separated by the use of fine osteotomies. The osteotomies are angled to the palate on the either side and a finger is kept in the palate to feel the instrument penetrating the palatal bone. The supra-apical division is similarly made through the palate with a curved osteotome. Once the tooth segment is mobile it is best to fix it to the adjacent teeth by means of an orthodontic arch and attachments.

In horizontal labial incision technique care is require when tunnelling vertically on either side of the tooth not to detach the labial mucoperiosteum on its anterior surface. The remaining procedures are same as described before. Immobilisation of tooth segment is required for several weeks.

Basic surgical principles of single tooth osteotomies are

(1) Maintain an adequate amount of attached, viable tissue to the mobilised segments in order to provide sufficient vascularity to them.

(2) Provide maximal direct visualisation of all areas to be osteotomised or ostectomised.

(3) Achieve good mobilisation of the segments to allow for passive repositioning in the predetermined position

(4) Maintain operational periodontal health.

(5) Provide good bony contact between the stable and mobilised segment to effect rapid bone union.Anterior Maxillary Osteotomy

An initial discussion of anterior maxillary osteotomy was presented by Cohn-stock in 1921. The single state predominantly labial approach was first reported by Wassmund in (1926). Axhatusen added a tunnelling procedure on the palatal side (1936), Schuchhardt (1956) preferred a two stage procedure, with the palatal side being treated first and completion of surgery 4-6 weeks later from labial approach.

The most popular technique of segmental surgery is the down fracture described by Epker and Welford (1980).

The anterior maxillary osteotomy is primarily employed

1. - Reposition the dento alveolar segment posteriorly

2. - Correction of maxillary protrusion

3. - Bimaxillary protrusion - along with mandible, (anterior segment)

4. - Correction of openbite (Secondary to mandibular correction)

In certain cases the dento-alveolar protrusion with or without vertical maxillary excess, it might be difficult to

decide between Anterior maxillary osteotomy and a Le fort I osteotomy with an anterior maxillary osteotomy to correct the deformity. In these situations these guidelines might be helpful.

If sufficient overbite exists and an impaction of 3mm or less is required then an isolated Anterior maxillary osteotomy would suffice.

If more than 3mm impaction is required and even if overbite exists le fort I osteotomy should be done in combination with anterior maxillary osteotomy.

If there is negative or minimal overbite, even if the maxillary impaction is minimal le fort I with anterior maxillary osteotomy is indicated.

If the maxillary impaction planned is minimal less than 3 mm, but if the gingival level between the teeth adjacent to the osteotomy has a steep angle, a Le fort I osteotomy with anterior maxillary osteotomy should be planned.

Wassmund technique: [ Labial vertical incision with palatal tunnelling]

The Wassmund approach relies on the buccolabial vascular pedicles and usually an intact palatal blood supply.

An anterior median vertical and buccal vertical incisions in the canine – premolar regions are made extending to the nasal floor. The mucoperiosteum is reflected posteriorly and superiorly. In the apical region of the canine tunnelling is carried out to the inferolateral border of the nasal pyriform aperture. Mucoperiosteal flap raised to expose pyriform rim and nasal spine.

Vertical bony cuts are made in the lateral maxillary cortex at the midpoint of planned osteotomy site. These are carried superiorly to a point approximately 3mm superior to canine apex. The anterior bony cuts are completed by continuing the cuts medially to a point on the most lateral aspect of pyriform aperture. These are made with tapered fissure bur.

On palatal aspect a subperiosteal tunnel is created on the area of planned palatal osteotomy. While the palatal tissue are protected with a suitable retractor the bony cut is carried from crest of alveolar bone in one osteotomy site across palate to opposite side. Care must be taken to avoid damage to nasal floor mucosa and penetration of endotracheal tube. Sometimes a small midline palatal incision aids in the removal of palatal bone.

The nasal septum is approached through the anterior vertical incision. The remaining bony attachments of the anterior maxillary segment are severed with a narrow single bevelled osteotome along the floor of nasal cavity.

The segment is manually freed by covering it with a gauze sponge, and manipulated to get free of all attachments except palatal pedicle.

It is tried into the post operative site. If any bony prominence interfering this can be removed. Final positioning is done with the aid of an occlusal splint. Before placement of splint the palatal tissue is closed with a horizontal mattress suture.

By this approach it is difficult to raise the maxilla and to setback posteriorly.

Wunderer's technique

Wunderer (1962) developed his procedure to provide a palatally oriented approach to the sectioning and reposition of anterior maxillary segment. Because of the segment is pedicled on labial mucoperiosteum it is possible to rotate it anteriorly for better visualisation of surgical site. Here bony section may take place under direct vision. This is indicated if posterior movement is the dominant objective.

Technique

Vertical incisions are placed on the labial and buccal mucoperiosteum. Subperiosteal tunnelling is done and osteotomy is done through the vertical incision on the buccal and labial aspect.

On the palatal aspect an arcing incision is made through the palatal mucosa from the inter-dental space anterior to the site of the planned osteotomy cut. The mucoperiosteum is raised on to the posterior palatal side. The buccal osteotomy cuts are joined transpalatally under direct vision. Care is taken to prevent damage to the nasal floor mucosa. If a midline split is required, it is fractured with a fine long bevelled osteotome.

The segment is freed completely by covering it with gauze sponge and with controlled manual force fracturing it from its remaining attachments. The recipients site is contoured with a bur. The mucoperiosteal flap is replaced with a horizontal mattress suture. The segment is fixed with pre-fabricated splint.

Down fracture technique.

Cupar 1955 modified two stage procedure of anterior maxillary osteotomy into single stage down fracturing technique. This technique is mainly indicated if superior positioning is the dominant objective. Epker described some advantage of this down fracture technique.

1. - It is technically simple

2. - Provides direct access to nasal crest of maxilla and associated nasal septal structures.

3. - Permit removal of palatal bone under direct vision.

4. - Gives excellent vascular pedicle.

The incision is made high in the labial vestibular mucosa at least 5mm above the root apices from premolar to premolar on the other side curving slightly in the midline towards the labial mucosa. Sometimes vertical incisions are placed anterior to the posterior osteotomy cuts.

The mucoperiosteum is raised to expose pyriform fossa, nasal septum, anterior nasal spine and the sub apical bone over the anterior tooth from premolar to premolar tooth.

The first premolars are extracted on both sides. The horizontal line of osteotomy is marked with bur starting from the pyriform rim up to the region of the extracted socket keeping at least 5mm above the root apices of the canine and incisors. The nasal mucosa is protected through out the procedure. Then the osteotomy cut is turned vertically down to reach the alveolar margin by tunnelling approach or under

direct vision when vertical incisions are used. Two vertical cuts are placed depending upon the amount of posterior setback. This buccal cortical bone is removed with a chisel.

After removing buccal bone the bur is directed to palatal bone in a semiblind fashion. A finger is placed on palatal aspect to feel the cutting process and also to prevent penetration of bur through the palatal mucosa is avoided.

The same procedure is repeated on the other side. Nasal mucosal floor is raised and the nasal septum is detached using a septal osteotome. The bone cut is completed on the palatal aspect with an osteotome by using gentle tap. Alternatively the palatal mucoperiosteum is raised and bur used to complete the cut sometimes small midline vertical incisions are placed in the midline to gain access.

The segment is then down fractured and the bone is removed from palatal aspect under direct vision.

The palatal mucoperiosteum is reflected slightly from the stable part (Posterior). This will allow easy movement of anterior segment posteriorly.

When superior positioning is planned the nasal spine is removed, the nasal floor in the mobilised segment is grooved to accommodate, the nasal septum, or a segment of septum is sectioned from its anteroinferior part.

After the indicated amount of bone is removed the splint is inserted. If the correct position is not attained, the osteotomy site is re-

examined and any bony projections are removed.

L shaped miniplates are used along the pyriform rim for fixation. Screws are placed at least 3mm away from root apices. Additional stability if needed can be achieved by wiring using a 26 gauge wire.

. During final positioning, care is taken not to crimp the palatal tissue between the segments as this would compromise the blood supply.

The wound toilet is done and the labial incision is closed in two layers. Any palatal or nasal floor tears are sutured with 3-0 vicryl. If alar base widening is significant then alar cinch suturing is done before mucosal closure.Posterior Maxillary alveolar Osteotomy

Unilateral or bilateral posterior maxillary osteotomy or ostectomy provides a means of surgically correcting a wide variety of occlusal and dento alveolar deformities. The relative indication of this procedure are.

(1) To alter the transverse position of the posterior maxilla (to correct cross bite).

(2) To superiorly position a supra erupted posterior segment.

(3) To inferiorly position a posterior segment. (To close a posterior open bite).

(4) To move a posterior segment forward to close an edentulous space.

Numerous technical approaches to the posterior maxillary osteotomy have been advocated. Schuchart (1955) described a two stage method applicable to the closure of a posterior open bite. In first stage the palatal bony cut is done and after 6 weeks the second stage, the buccal osteotomy, is performed.

Kufner (1968) modified this technique to a one stage procedure. In this only buccal approach is done and palatal bone is divided through the osteotomy site by a thin osteotome as in case of down fracture technique.

West and Epker 1972 also described similar procedure. Regardless of the technique utilised, principles of surgical reposition in this are similar to anterior segmental surgery.

The technique.

Access to the posterior segmental osteotomy is gained through a buccal sulcus incision extending from 1st molar to canine region. Then it is turned vertically down to marginal gingiva one tooth anterior to osteotomy site. The muco periosteal flap is reflected to expose the lateral aspect of alveolar portion, lower part of zygomatic buttress and posteriorly to the pterygoid plates if needed. If a tooth is planned to extract from the posterior end the mucosal reflection is limited to that region.

After bone is exposed the bony cut is marked by measuring with calliper and marks with pencil. The bony cut should be at least 5mm above the root apices in order to preserve blood supply.

A predetermined amount of bone is removed from the buccal aspect (lateral maxillary wall) and the inter-dental alveolar osteotomy is then completed from the buccal aspect. Carefully expose the sinus mucosa and reflect it superiorly. In cases of excessive supra-eruption of dento-alveolar segment the plane of osteotomy will be below the antral floor.

Now the palatal bone is divided. It can be done using bur or osteotome. In both cases a finger is placed as palatal mucosa to feel the instrument as it breaks the palatal bone.

If the osteotomy is extending posterior to 2nd molar, the level of bone cut is lowered posteriorly. This will help easy separation or division of pterygoid plates.

If the osteotomy site at buccal aspect is small it will be difficult to cut the palatal bone through this. In such cases a palatal incision is placed anterior to the area of bone cut mucosa can be tunnelled and osteotomy can be done under direct vision.

The segment is down fractured with the osteotome placed in bone cut and lowered inferiorly. A small curved osteotome is used to separate the pterygoid plates. The bone removal is now completed. If needed palatal mucoperiosteum can be reflected from stable part. On posteromedial aspect of segment palatal neurovascular bundle can be identified. Bone is removed carefully surrounding this and can be freed.

After the bone removal is completed the segment can be fixed with preformed acrylic splint.

Total maxillary osteotomies

Le Fort I Osteotomy.

Early effort to reposition the entire maxilla were directed at correcting traumatically malpositioned maxillary complex, and also to correct midface deformities secondary to cleft palate. The danger of maxillary sinus infection and fistulae as well as the possibility of necrosis of bony segment deterred, many surgeons from attempting this correction.

Wassmund (1927) performed this type of surgery to close a posterior openbite and in this after sectioning the lateral maxillary wall be used elastic traction to bring the maxilla down. Axhausen (1935) was first to advance the lower portion of maxilla using this technique. Schuchardt (1942) applied forward traction using a pulley and weight system to produce an advancement of sectioned maxillary segment.

Transection of pterygoid plate in Le Fort I maxillary osteotomy was described by Schuchardt 1942. Moore and Ward 1949 advocated the use of horizontal transection of the pterygoid for anterior advancement of maxilla.

Cupar and Rowe 1954 reported the use of bone grafting in Le-Fort I maxillary advancement. Cerinac and associates (1955) and Cerinac in (1958) were also reported the use of bone grafts.

In 1959 Kole developed a two stage procedure for total maxillary osteotomy. In the first stage he performed a U shaped palatal osteotomy anterior to greater palatine foramen and in second stage a labial bone cut is made. Paul

(1966) reported a similar procedure in a single stage. Obwegeser 1969 introduced a technique of wedging of bone graft between the pterygoid process and tuberosity for advancement of maxilla after surgery.

Dupont, Ciaburo and Prevost 1974 advocated sectioning through the tuberosity rather than at the pterygomaxillary interface. This modification was described by Trimble, Tideman and Stoleinga 1983.

Bell at al 1975 described down fracture technique of Le Fort I Osteotomy. Epker and Wolford (1980) rectified this technique and described it in detail. The advancement studies were done by Bell and Scheindermann (1981). The associated changes in facial muscle was studied by Schendel (1983). Luhr and Radney 1986 described the use of rigid fixation by miniplates in Le Fort I osteotomy.

Indications of Le Fort I Osteotomy

1. Altering the vertical dimension of maxilla

- Superior positioning in long face syndrome

- Inferior positioning.

2. Antroposterior movements of maxilla

In cleft palate patients & congenitally deficient maxilla

- Maxillary advancement

- Maxillary set back in maxillary prognathism

(only 3-5mm is possible)

3. Levelling of occlusal plane in occlusal cant.

4. Surgical expansion of maxilla

5. Narrowing of maxilla.

TECHNIQUE

A horizontal vestibular incision is made from the mesial aspect of the maxillary first molar from one side to the other side about 5mm above the apices of the maxillary teeth. The incision can be made with blade or diathermy. The mucoperiosteum is reflected to expose the pyriform aperture and lateral wall of maxilla. Posterior to zygomatic buttress the mucoperiosteum is tunnelled to expose the tuberosity. The elevation of mucoperiosteum is extended to infra orbital neurovascular bundle. Nasal mucosa is reflected from lateral nasal wall, floor of the nasal cavity and from the lower end of the nasal septum.

The osteotomy line is marked on the bone over lateral aspect. It should be 5mm above the apices of teeth, sloping down ward posteriorly. Vertical reference lines can be marked to access the anteroposterior movement of the mobilised segment. Osteotomy cuts are then completed with a flat fissure bur or with an oscillating saw. Bone division starts from lateral wall of pyriform aperture and taken posteriorly. Brisk oozing is sometimes noticed along the anterior maxillary wall. For maxillary impaction the planned amount of bone is removed from the lateral maxillary walls of the maxilla after marking out two line anteriorly. Posteriorly these lines are merged or kept parallel depending upon the type of movement required. noticed Bone removal should be done. This gives a narrow, well controlled bone cut. In case of superior repositioning the cut can be made with bur as some amount of bone removal is indicated.

The lateral wall of maxillary sinus is then divided. A retractor is used to protect the buccal soft tissue. This cut is taken posteriorly to pterygomaxillary junction. Lateral wall of nose is divided below the inferior turbinate with a flat osteotome. The cut is directed towards the perpendicular plate of palatine bone which is partially divided. Complete division may cause excessive bleeding from palatine vessels.

The nasal septum is divided with a septal osteotome, along the floor of nasal cavity. The osteotome is hold parallel to occlusal plane. The endotracheal tube is protected now. After all the walls are divided , a curved osteotome is used to complete the bone cut at pterygomaxillary junction. This is separated by gentle tapping . A finger is kept posterior to pterygoid hamulus to feel the separation.

Maxilla is now down fractured by thumb placed over the alveolar bone. As the down fracturing progresses the nasal mucosa is reflected posteriorly.

Some times the separation may be achieved by disimpaction forceps or by use of special instruments like smith split spreader.

For superior and posterior positioning elective bone removal is done with rounger or bur. The removed bone chips can be collected in saline for filling the gap after fixation as autogenous grafts. This will speed up bone healing . Posterior repositioning with osteotomy of the pterygoid plates is difficult. Only 5 to 6 mm of posterior movement is possible. If excess movement is desired then a two piece maxillary osteotomy is to be planned or a maxillary tuberosity osteotomy is planned.

For maxillary advancement the bone graft is placed between the pterygoid process and maxillary tuberosity. For this communication of pterygoid plates should be prevented during separation of pterygomaxillary junction. Intact pterygoid plates will act as a posterior stop for bone grafts. some authors described a vertical step in the lateral cut in the region of the second premolar. This aids in measuring the movement and also to serve as stop for any bone graft that may be placed in the region.

In congenital maxillary hypoplasia a 3-5mm stable advancement is possible without placing bone grafts.

In cases of augmentation of vertical maxillary height the bone cut is made a higher level with respect to pyriform aperture. This is to get 5mm of bone in sub apical region after the osteotomy of lateral and medial walls. The maxilla is advanced and lowered using rows disimpaction forceps. The beaks are applied below the nasal mucosa and gentle rocking of the maxilla will help to relieve soft tissue resistance to anterior traction. After adequate inferior traction bone grafts 9 split thickness calvarial grafts ) are fixed in position.

Segmentalization of the Le Fort I segment can be done if necessary, taking care to preserve the vascular pedicle. The common segmentalization procedure include:

1. Anterior maxillary osteotomy

2. Sagittal midline osteotomy.

The anterior maxillary osteotomy is combined with Le fort I impaction in patients who have vertical maxillary excess with dento-alveolar protrusion of moderate to severe

degree. The osteotomy is usually carried out through the socket of the extracted 1st or 2nd premolar. The bone cuts are made through tunnelling of the mucoperiosteum for access. Care is taken to preserve the pedicles.

Alterations in transverse dimension if required can be performed after down fracture. In cases requiring expansion a mid palatal split is done using a fissure bur. The palatal muco periosteum is protected while doing this. After bone division the Mucoperiosteum is reflected through the osteotomy gap and extended to vertical alveolar portion. Should not damage the palatal vessels. Up to 6mm of expansion is possible without bone grafting. If excessive expansion is done the stretching of palatal mucosa may lead to ischaemia and necrosis of bone as well as soft tissue. If the bone gap is more than 6mm partial thickness parietal bone graft should be fixed in this gap.

In case of narrowing of maxilla the alveolus should be divided in midline before down fracturing and then the down-fracturing is done and the division of palatal midline is done posteriorly. The mucoperiosteum is reflected from the edge of osteotomy and adequate bone is removed from midline. Then by pushing the mucoperiosteum into oral cavity the segments can be fixed together with inter osseous wiring. Alterations of occlusal plane may be required in some cases. Oblique occlusal plane can occur in patients with unilateral condylar hypo/ hyperplasia, hemifacial microstomia, Romberg syndrome etc. The assessment of this defect should done by clinical examination and evaluating PA cephalogram. This condition is treated by.

- Increasing vertical Ht. of maxilla on one side.

- Decreasing vertical height on one side.

- or a combination

A combined form of treatment is often more practical because of concomitant soft tissue changes. Hence the height is increased slightly on side of deficit and decreased on side of excess. This should be accompanied by mandibular surgeries to attain complete occlusion. For levelling of occlusal plane the maxilla is released in Le Fort I plane. The excessive bone is removed from one side. The other side is augmented by bone graft. Corticocancellous grafts from iliac crest is ideal if excessive alteration is required.

Fixation

After the required corrections, the maxilla should be fixed to the basal bone. Historically, the mobilised maxilla was fixed directly to the pyriform rims and zygomatic buttress with transosseous wires or suspension wires placed at the zygomatic buttress, the zygoma or in the infra orbital rim.

In cases of transverse corrections a prefabricated acrylic splint should be placed to get three dimensional stability of the occlusal plane. In other cases a temporary inter maxillary fixation should be done. During this it should be ascertained that the condyle of mandible is in glenoid fossa. After the IMF is done the segment is fixed superiorly.

In cases of superior and backward positioning a circum zygomatic suspension can be done. This gives a postero-superior force. The wires are tightened simultaneously on both sides.

In maxillary advancement without inferior positioning a infra orbital rim suspension is recommended. This gives a upward and anterior vector of force.

The inferior positioning is difficult to fix by these methods. Wiring at lateral pyriform border can be done. Simultaneous wiring of bone graft also to be done.

Instability of the maxillary repositioning has been noted and these have been attributed to various factors. These include

1. Inadequate bone stabilisation

2. Poor bone contact.

3. Excessive superior repositioning or superior relapse of an inferiorly placed maxilla may be due to the mandibular occluding forces as the masticatory muscles contract.

4. Maxillary advancement is also plagued by relapse, especially following large forward movements or due to excessive soft tissue restriction after multiple or cleft surgeries.

To overcome these problems more rigid forms of fixation are devised. These include rigid adjustable fixation and rigid internal fixation.

Rigid adjustable fixation for maxillary osteotomy

These uses mainly pins and wires to secure the maxilla. Various forms of rigid adjustable devices had been advocated. Bays 1985 suggested the use of 2.7 mm screws in the superior segment. Pins are attached to the arch wire.

Then 0.045 inch orthodontic wire is used to stabilise the maxilla to the screws and pins. This can be adjusted postoperatively for minor adjustment in maxillary position.

Bennett & Wolford 1985 suggested another system where in they used 2mm Steinmann pin into the zygomatic buttress area. They secured it to the arch wire using acrylic. They obtained anterior stabilisation by rigid internal fixation by means of miniplates.

These pins can be removed after healing by local anaesthesia and intravenous sedation.

Internal rigid fixation for maxillary osteotomy.

Rigid fixation with screws and plates gives satisfactory stable fixation in all forms of osteotomy. This is especially important in inferior positioning of maxilla which is least stable when other forms of fixation are used. Simultaneous fixation of bone grafts also can be achieved with rigid fixation. This will improve the graft viability. In Le Fort I osteotomy the areas suitable for rigid fixation are zygomatic buttress and pyriform margins. These areas having adequate bone thickness of insertion of screws. After the planned post operative position is achieved and temporarily IMF performed straight, L shaped or T shaped plates suitable for 2mm screws are passively adapted in these areas. Improper adaptation will lead to alteration of occlusion later. The holes should be perpendicular to surface in-order to achieve maximum bone thickness for screws.

Ian Munro (1989) recommended at least 4 plates should be used for Le-Fort I osteotomy. Two at zygomatic buttresses, two at lateral pyriform margins. Each plates

should have 4 holes minimum 2mm monocortical self tapping screws are widely accepted.

McCarthy (1990) recommended that if rigid fixation is planned the osteotomy should be done at a higher level in order to get adequate bone at sub apical region for placement of screws without endangering root apices.

Stella & Epker 1994 advocated semirigid fixation with posterior zygomatic buttress wiring and anterior plates in the pyriform rim. The posterior zygomatic buttress wiring can be adjusted depending on the occlusal needs of the patient.

Wound closure & Soft tissue considerations.

After satisfactory fixation the area is irrigated inspected for loose bony fragments, and any other foreign bodies. Closure of the incision line can be done in two layers. Before that any mucosal tear should be sutured with 4 '0' catgut. This will reduce the chance of post operative nasal bleeding.

Widening of alar base is a frequent complication of superior positioning of maxilla. This can be prevented by a traction suture ( alar cinch suturing ) with a non observable material across the alar base. Gahli & Sinn 1997 advocated Weir procedure or a simple lateral nostril sill excision with undermining and re-approximation for management of increased alar base width. Other authors have advocated the use of secondary rhinoplasty techniques for management of the alar basal width problems. Kawanato (1989) recommended separation of anterior nasal spine from maxilla along with nasal septum. This will retain the soft tissue contour at the nasal base.

The upper lip length and vermilion exposure changes drastically with Le fort I osteotomy. Lip length reduces by 20 % of the planned bone movement in a Le fort I impaction with reduction in vermilion exposure. V- Y closure of the mucosa with a vertical limb of 10 –15 mm maintains the pre-operative vermilion exposure and lip length. A vertical limb of 15 – 25 mm increases lip length by about 1 –2 mm and also increases vermilion exposure. Appropriate use of these closure method is indicated depending upon the treatment plan.

Total Maxillary alveolar Osteotomy (TMAO) (Hall and Roddy 1975)

Total maxillary alveolar osteotomy was described by Paul 1969 based on the experiences of Kole & Mohnac. Hall & Roddy 1975, West and McNeil 1975, Hall and west (1975) , West & Epker 1972 also published this as a treatment for total maxillary alveolar hyperplasia. Meloney et al (1982) reviewed few cases of this and concluded that TMAO is a "good technique in his time"

Sterling R. Schow (1986) described few advantages

(1) It can be used to intrude maxilla for hyper plastic maxillary alveolus, to correct posterior or total alveolar hyperplasia with or without anterior open bite. This is particularly useful when impaction of the segment is more than 5mm.

(2) It is a substitute for Le Fort I surgery when there is long alveolar process with high arched palate.

(3) The reduction of sinus volume and possibility of air way constriction is avoided with TMAO.

(4) Even in absence of vertical excess, this can be used to expand, constrict or recontour the alveolar arches. In such cases it provides a stable palatal base to which the segments can be fixed.

(5) It is less suitable for inferior positioning or advancement.

Epker and Wolford 1980 described this technique as "superior positioning of maxilla with nasal floor intact". They gave the indications for this procedure.

(1) When superior movements 10-15mm is required.

(2) In pre-existing decreased nasal airway function not related to nasal septal deviation (DNS) or large inferior turbinate.

(3) when segmentalisation of maxilla is required in 3 or 4 segments.

Technique.

This may be accomplished with surgical access obtained through a horizontal mucoperiosteal incision near the depth of the labial vestibule similar to that of Le fort I down fracture technique or through multiple vertical incisions with tunnelling beneath the alveolar mucosa and palatal access through incision and elevation of a palatal "horseshoe" mucoperiosteal flap.

A circum-vestibular incision is made which extend from one Zygomatico alveolar crest to the other. Posterior to that the soft tissue is undermined to the pterygomaxillary junction.

The alveolar portion and lateral maxillary wall is exposed by minimum but adequate elevation of mucoperiosteal flap is done.

The nasal epithelium is elevated starting from pyriform aperture to 10-15mm posteriorly, and also from the anterior floor of nasal cavity and inferior portion of septal cartilage.

By protecting the nasal mucosa with a retractor the horizontal osteotomy through the lateral maxillary wall is made extending from the nasal cavity to the pterygomaxillary junction. The anterior 10 to 15 mm of lateral nasal wall is also transected. If superior impaction is planned, the inferior osteotomy is completed 4 to 5 mm above the apices of the tooth and this is followed by a superior osteotomy to remove the measured amount of bone. Posteriorly the osteotomy is directed towards the pterygomaxillary junction or to the third molar extracted site which has been removed 4 to 6 weeks prior to surgery.

If the dentoalveolar segment is to be divided into multiple segments, the mucoperiosteum overlying the alveolus at the site of osteotomy is tunnelled and the osteotomy cut performed. The palatal bone at the vertical osteotomy site is cut taking care to prevent damage to the palatal periosteum.

A 'V' shaped groove is cut from the anterior nasal floor in the midline after separating the nasal septum from floor of nasal cavity. This should be 4mm away from root apex of central incisor. This is to accommodate the nasal septum during superior positioning of maxilla. If this clearance is not possible the anteroinferior portion of septum should be sectioned.

The palatal bone cuts are made. In the anterior region if there is large amount of bone in the alveolar segment then bone cuts are made inferior to the floor of the nasal cavity. With a small osteotome or a fissure bur a transnasal osteotomy is completed from right to left across the palate approximately 10 to 15 mm into the nasal cavity. A palpating finger is placed on the palatal side to avoid damage to the palatal mucosa. Laterally the bone cuts extends into maxillary sinuses. Posteriorly the osteotomy cuts extends along the medial wall of the maxillary sinus below the level of the nasal floor into the oral cavity.

Two osteotomes are inserted in the osteotomy gap and is levered down wards to down fracture the maxilla. If it fails a curved osteotome is used to remove palatal bone posteriorly. This should be carefully done.

If the 3rd molar is to be removed either due to impaction or any other causes it can be done at this time. If so the osteotomy can be limited to 3rd molar socket. Or the pterygomaxillary junction can be disrupted by gentle tapping with osteotome.

After down fracture adequate bone is removed from palatal side and the segment can be moved to its pre-planned position.

The palatal mucoperiosteum can be undermined carefully from the fixed part. This will help in easy positioning of the segments.

The mobilised segments are now repositioned by selective bone removal and the planned postoperative position is attained.

The fixation can be done by a prefabricated occlusal splint made from mock surgery on study model. Or the fixation can be done with orthodontic appliance. A temporary inter maxillary fixation is performed to ascertain the anteroposterior relation. The segment is now fixed superiorly. In cases of superior and posterior placement, a circum-zygomatic suspension can be used. If the repositioning is in a superior and anterior direction suspension to infra orbital rim can be done.

Alternatively a lateral pyriform rim wiring can also be used. Now the temporary inter maxillary fixation is removed and the wound is closed.

Some modifications are suggested to this standard technique.

Bell 1975 used the same incision as in Le-Fort I Osteotomy.

Bell, West (1975) West and Roddy 1976 and McNeil on (1975) described a combined palatal and labial approach. In this on the labial aspect 3 vertical incisions are used one in midline, other in premolar region on both sides. Through this sub mucosal tunnelling is done and osteotomy is performed on buccal and labial aspect. After the buccal osteotomy is completed a palatal mucoperiosteal flap is raised. For this a U shaped incision is put about 1cm apical to gingival margin starting from one 2nd molar region lateral to the greater palatine vessels. It is brought anteriorly just lateral to greater palatine vessels, Anteriorly is turned to opposite site just palatal to incisive papilla, and extend to other 2nd molar. A full thickness mucoperiosteal flap is raised. Now the palatal bony cut is done directly, dividing the palatal wall of maxillary

sinus and anterior nasal wall. Posterior to the greater palatine foramen the bone may fractured or divided with osteotome. After adequate bone is removed the segment can be fractured using digital pressure or by levering instruments. Selective bone removal is done and the segment is repositioned and fixed. This technique has advantage of direct access to the palatal bone and is suitable in cases of thick palate. But the palatal vascular pedicle is compromised.

All the authors suggested that if there is adequate bone in sub apical region and below the nasal and antral floor, the osteotomy should be done at this plane without entering the nasal and antral floors for impacting the maxilla.

Quadrangular Le Fort I osteotomy.

Hugo Obwegesser 1969 described a high Le fort I osteotomy for correction of midfacial hypoplasia in cleft lip and palate patients. This was named Quadrangular Le Fort I osteotomy by Keller & Sather 1989, because of the indications, osteotomy shape and level and projected clinical outcome were quite similar to those of the quadrangular Le fort II osteotomy as described by Kufner. Here the advancement of both the infra orbital rim and a portion of the zygomatic complex is done.

Indications

This is mainly indicated in patients with maxillary-zygomatic horizontal deficiency, with class III skeletal malocclusion and normal nasal projection. This is ideal in management of midface hypoplasia with midline problems or transverse deficiency.

Procedure

The procedure is done intraorally through the down fracture approach of Le Fort I osteotomy by a horizontal vestibular incision. The entire surface of the anterior maxilla is exposed by subperiosteal dissection extending from the right to left tuberosity and up to the infra orbital rim. The infra orbital nerve is isolated and the orbital rim periosteum is reflected. The mucosa over the floor of the nose is exposed and also from the lateral nasal wall.

The osteotomy cuts are placed on the lateral wall of maxilla from the pyriform aperture at the level of the infra orbital nerve. The osteotomy is extended laterally below the level of the infra orbital nerve to the tuberosity and pterygoid plate region. The maxilla is down fractured after detaching the nasal septum, pterygomaxillary disjunction and ostectomising the lateral nasal wall.

Bone grafts are used in the infra orbital region and also in the pterygomaxillary junction.

Le Fort II Osteotomy

Converse 1971 described an osteotomy for correction of the nasomaxillary hypoplasia. This was classified as "Anterior Le Fort II osteotomy" by Steinhäuser 1980. Henderson and Jackson (1973) described classical Le Fort II Osteotomy for patients with naso maxillary and midface hypoplasia. This was classified as "Pyramidal Le Fort II osteotomy" by Steinhauser. Kufner (1971) described an osteotomy for correction of nasal hypoplasia and also for the infra orbital region. Similar osteotomies were described by Souriyas et al 1973and Champy 1980. This was classified as

"Quadrangular Le Fort II osteotomy by Steinhauser. Epker and Wolford in 1980 given a detailed description of standard Le Fort II Osteotomy.

Anterior Le Fort II osteotomy. (Naso-Orbito-maxillary osteotomy).

It is an initial form of Le Fort II osteotomy described by converse and associates (1971). Used to correct the nasal and maxillary deficiency. The principles of these procedure are:

- The foreshortened nasal septal frame work must be advanced as it will oppose

nasal lengthening.

- A forward and downward placement of nasal and maxillary complex is required to correct midface deficiency.

- The naso lacrimal apparatus must not be disturbed.

- Bone grafts should be used to restore the Bone deficiencies.

- Skin coverage and nasal lining must be provided to accommodate the nasal

elongation.

The upper part of this osteotomy done, through a V shaped incision with the apex at glabella and extended bilaterally along both sides of nose to reach just above the alar base. The cartilaginous and bony part of nose is separated and the columella is pulled down.

Osteotomy begins at lower end of nasal bone directed medially to the medial wall of orbit than downward

to reach the floor of orbit posterior to naso lacrimal apparatus. Then it is brought to infra orbital margin medial to the nerve and extended downwards to the alveolar bone posterior to 1st premolar. Then a posteriorly based palatal flap is raised and 5/5 are extracted the osteotomy is completed through the sockets of this dividing hard palate. Now the segment is mobilised and advanced. This can be fixed by a prefabricated acrylic splint.

This Procedure:

- Lengthens the nose

- Nasal tip moved anteriorly and downwards.

Advances anterior maxillary segment.

This technique was modified by Psillakis & Co worker 1973 by taking a transverse osteotomy above the apices of anterior teeth and augmenting the nasomaxillary segment. This is not biologically sound so this technique is hardly used nowadays.

Pyramidal Le Fort II osteotomy.( Classical Le Fort II )

This is indicated in Naso maxillary abnormalities such as.

- Binders syndrome

- Crouzon's Syndrome

- Apert's syndrome

- Extreme Cleft palate cases

- Midface deficiency with short nose and class III Occlusion.

This osteotomy is performed through a coronal incision, a bilateral lateral nasal incision and an intraoral upper vestibular incision.

After subperiosteal elevation of flap the lateral aspect of nasal bone, medial canthal ligament and lacrimal apparatus are identified. Osteotomy begins just below the frontonasal suture and extended posteriorly, then downwards anterior to attachment of canthal ligament.

Then behind or anterior to nasolacrimal opening to reach the floor of orbit. The osteotomy is brought anteriorly to reach the infraorbital margin. It is divided at planned position and then proceed on anterior wall of maxilla, posteroinferiorly to infraorbital foramen. Now through the intraoral sulcus incision the osteotomy proceed below the zygomatic buttress as in Le-Fort I Osteotomy. The procedure is repeated on opposite side of using a curved osteotome the maxilla is separated from skull base at naso ethmoid region. The nasal septum is separated using a nasal septal osteotome in a posterior and downward direction. Now using Row's forceps to maxilla is rocked and advanced.

Bone grafting are done at the infra orbital region.

Quadrangular Le Fort II Osteotomy

Kufner1971 described an osteotomy which was in essence a combination of Le fort I and Le Fort II osteotomy. This was modified by Stoleinga & Brouns in 1996.

The osteotomy starts from upper part of pyriform aperture to reach the floor of orbit medial to infraorbital foramen. Then another osteotomy starting from tuberosity extended along the zygomatic buttress to reach the infra

orbital rim lateral to foramen. These are connected in the floor or orbit. Thus a U shaped osteotomy separates maxilla without disturbing nasal base. It is indicated in patients with prominent nose with paranasal deficiency.

After advancing maxilla fixation is done similar to Le Fort I. If there is severe nasal hypoplasia augmentation of nose is done with calvarial bone graft and soft tissue augmented by a V-Y procedure.

Stoleinga & Brouns 1996 advocated a modification in which the osteotomy cut goes around and below the infra orbital foramen to prevent damage to the nerve.

Le Fort III Osteotomy

This osteotomy more or less follows the classic Le Fort III fracture line. It is mainly used for advancing deficient midface. Midface deficiency can affect maxilla, zygoma and nasoethmoid complex either individually or in various combination. Accordingly the surgical plane must be altered. Le Fort III is indicated in a combined maxillary, zygomatic and nasal deficiency. In case of normal nasal projection and maxillary and zygomatic deficiency a modified maxillary malar osteotomy is suggested.

The access for Le Fort III osteotomy can be achieved through a bicoronal incision, Transconjunctival incision, Glabellar, or sub Ciliary incisions and through an intra oral upper buccal sulcus incisions.

After reflecting a bicroronal flap the fronto nasoethmoidal region, lateral orbital rims, are exposed. The infraorbital rim and orbital floor are then exposed through a subciliary incision.

The infratemporal space is exposed by reflecting temporalis inferiorly. The medial canthal tendon are detached and tucked with suture.

Osteotomy begins just below the fronto nasal suture and passed medialy to divide ethmoid bone and through the medial wall of orbit it enters the orbital floor. The infraorbital neurovascular bundle is dissected out of bone and osteotomy is continued laterally to reach in the inferior orbital fissure. Now the lateral orbital wall is exposed and osteotomy begins at area of deficiency. This is connected to the anterior end of inferior orbital fissure. Now the pterygomaxillary junction is exposed through intraoral incision. Using chisel pterygoid plate is separated from maxilla. This is extended superiorly to inferior orbital fissure. The nasal septum is separated through the osteotomy site is the frontal region. The cut passes through perpendicular plate of ethmoid and vomer. At this level bleeding is less and chance of damage to olfactory fibres are less.

Mobilisation of maxillary malar complex is now done by using disimpaction forceps. By gentle rocking movements the segment is gradually moved to the required position.

Bone grafts are placed at lateral orbital rim and glabellar region and secured with wires. Onlay grafts are also placed for augmenting the infraorbital rim, frontal area etc; Medial canthal ligaments are replaced by non absorbable suture in a figure of 8 manner. Miniplates are applied at frontozygomatic osteotomy site, the fronto nasal osteotomy, and between zygomatic arch and zygoma. Before placing the miniplates inter maxillary fixation is applied in a slightly over corrected

position. After rigid fixation this is removed. The bicoronal flap is now closed 2-3 suction drains are applied.

Malar maxillary advancement

It is modified Le Fort III osteotomy. It is indicated for individuals with malar and maxillary deficiency with normal bone projection. In this the osteotomy begins at medial end of inferior orbital rim just lateral to lacrimal apparatus. It is connected to pyriform aperture. Along the floor of orbit, without making injury to inferior neurovascular bundle the osteotomy proceed to lateral orbital wall just below the whitnal's tubercle the lateral orbital wall is divided. Then osteotomy extended lateral orbital wall is divided. Then osteotomy ex tended lateral to zygomatic eminence in an oblique manner brought anteriorly to the inferior border root of zygomatic arch. Now through an incision in posterior aspect of upper buccal sulcus the lateral wall of sinus and pterygoid plates are divided as in Le Fort I surgery.

Now through anterior sulcus incision the nasal cavity is exposed and the nasal septum is detached. This and division of lateral nasal wall is done as in Le Fort I surgery. Now the segment can be advanced with forceps, slight over correction is done and fixation is done at fronto zygomatic and lateral pyriform rim regions.

Complications of maxillary orthognathic surgeries

Maxillary surgery produces relatively few complications when the operative procedure is well conceived, carefully planned and precisely executed. The majority of the problems that do occur result directly or indirectly from careless and inadequate planning.

Incorrect line of fracture

Incorrect line of fracture usually occurs during pterygomaxillary disjunction and also during down fracture.

The ideal fracture that separates the pterygoid and the tuberosity should do without damage to the either parts. Improperly directed force would result in fracture of superior part of maxillary sinus, a high horizontal fracture of pterygoid plates or a damage to pterygoid canal can occur. Directing the force with a small osteotome from the posterolateral to antromedial aspect would result in a more predictable cut. If the pterygoid plates is fractured in which advancement is planned, mechanical support by means of bone grafting at the pterygomaxillary junction will offset the incorrect fracture and prevent postoperative relapse.

Hemorrhage:

Bleeding can be a major concern in maxillary surgeries. During surgery blood vessels most commonly encountered are greater palatine artery. internal maxillary, nasoethmoidal vessels, posterior superior alveolar artery and pterygoid venous plexus. It is generally recommended that hypotensive anaesthesia should be used for midface osteotomies. Richard Ellis et al 1990 reviewed cases of life threatening post-operative bleeding after Le Fort I osteotomy. In most occasions descending palatal artery was the source of bleeding and in some case the internal maxillary artery. Pressure packing with a posterior nasal pack, ligation of upper part of external carotid artery and selective embolisation technique were used. Closure of tear of nasal mucosa before wound closure will reduce postoperative epistaxis.

Infection

Increased chance of infection in midface surgery is due to communication to nasal and oral cavities. Behrman (1972) reported only 3cases of infection out of 600 maxillary osteotomies. A double blind study of Eschelman 1986 showed a significant reduction of infection with antibiotic prophylaxis .Obviously good surgical technique good closure of soft tissue incisions and maintenance of good vascular supply will help to minimise the infection McCarthy and Converse 1972 questioned routine use of antibiotic prophylaxis. They listed some of the indications for prophylactic antibiotics in orthognathic surgery.

- An intraoral surgical approach

- Previous irradiation of operative sit

- Use of bone grafts

- Use of alloplastic implants

- Poor oral hygiene

- Patient prone to infection.

Oedema

Excessive oedema is common in midface surgeries. It is disappointing to the patient. It is due to laxity of subcutaneous tissue of midface. Shelton and Irby (1980) recommended use of steroids in initial post operative period. They used dexamethasone sodium 8-10 mg. 6th hourly, first dose being started at operating room. This is continued for 48 hourly and following this methyl prednisolone acetate 80 mg. is given for next 2 days.

Loss of Segment:

Decreased blood flow may lead to loss of segment and delayed union. This can occur in segmental surgeries. This is due to improper vascular pedicle and subsequent ischemic necrosis. In case of retained buccal mucosal pedicle this complication is rare when compared to total sulcus incision. The damage to palatal mucosa during palatal bony cut is common cause of this. Use of ill fitting splints which causes excessive pressure can cause ischaemia. Avascular necrosis will lead to gingival infection, gingival recession, loss of alveolar bone, loss of teeth and total loss of segment.

If ischemic necrosis occurs-

- Keep good oral hygiene.

- Prophylactic antibiotics to be given.

- Retain teeth as much as possible. Some bone may revascularise later..

Epker 1984 recommended the following steps to avoid ischaemic necrosis

1. Avoid transection of greater palatine vessels.

2. Stretch (as opposed to tear) the soft tissue during mobilisation of maxilla.

3 Make appropriate palatal soft tissue relaxing incisions for simultaneous expansion.

4. Consider a vertical vestibular incision in potentially troublesome cases.

Relapse:

Relapse can occur at various stages of orthognathic surgery. It can be immediate or short term relapse or long term (delayed) relapse.

Short term relapse can occur during fixation by I.M.F. If the fixation of osteotomised segment is not stable and IMF is done after the fixation of surgical segment this can occur. IMF should be done before fixing at osteotomy site. Relapse mostly seen with interosseous wiring. If maxillary walls are very thin the relapse is more. This should identified at time of surgery and adequate bone grafts should be placed.

Long term relapse is mainly due to soft tissue traction mainly seen in advancement cases. Anterior and inferior advancement showing more relapse, maxillary expansion, if exceeds more than 6-7 mm, shown high relapse. The Superior placement of maxilla is reported to be more stable. Among segmental surgery posterior subapical advancement for closure of posterior openbite shown excessive relapse tendency.

Will man (1970) studied 106 cases of maxillary Le Fort I advancement. He found stable results for 3 years - 1 mm posterior movement noted in first year and the superior movement was 1.8 - 2.8 mm. in first year. More relapse was noted in male patients.

Tessier and Shiter (1982) also reported a similar study. In his study bone was stable after 1 year, and upper lip lost 44% of its advanced position.

Carloti and Scheudel (1987) Oaus worth 1984 where studied the osteotomy site histologically. They showed healing of the site with impact bone.

Ward Booth, Bhatia and Moose (1984) showed a relapse of more than 30% in Le-Forte II advancement. In a study normal patients (without cleft palate) Batton and Moose showed little evidence of relapse with Le Forte II Advancement.

Nerve injury

The injury to infra orbital nerve is seen in high Le Fort I, Le Fort II and III osteotomy. Damage to the nerve occurs during manipulation of incision, bone cutting and anterior repositioning of the maxillary segment.

Loss of tooth vitality and sensitivity.

Vitality of tooth is maintained by the blood supply where as sensitivity by the nerve supply. When the blood supply is lost pulp becomes necrotic and discoloration of tooth and periapical changes begins. But in cases of loss of nerve supply alone the vascularity is maintained and tooth will be vital. However some fibrosis and calcifications will result. Bell et al (1969) in an animal study shown that if the apical bony cut is done 0.5 cm or above the apex and any of one flap (palatal lingual or buccal) is retained to the segment both vitality and sensitivity will be remaining. They demonstrated neural and vascular plexus connecting this flaps with apical vessels and nerves. D. Poss Willo (1972) demonstrated progressive loss of odontoblasts in teeth of osteotomised segment. Banks (1978) in an animal study demonstrated progressive fibrosis and calcification in teeth

involving osteotomised segment. But these teeth remain vital even after 52 weeks postoperatively. Pulpal changes also reported by Hutchinson and McGregor, Kart and Hinds (1971) in 4 years. Following -up study of 25 patients with segmental osteotomy reported that 1-15 mm periodontal bone loss occurring in one year after surgery. Less bone loss is seen in younger individuals. Maximum retention of flap over segment showed better results.

Perpesack (1973) reported 94-95% of teeth regained sensitivity after 12 months in maxilla and 72% in mandible. McArthur and Turvey (1978) reported 2% loss of sensitivity, Kanberge and Ergstorm (1988) reported loss of sensitivity in 90% teeth following Le Fort I Osteotomy. After 18 months all of these regained sensibility.

Mohd El Dep (1984) recommended following precautions to avoid damage to root and periodontal structures.

1. Avoid multiple segmentalisation if orthodontic alignment is possible.

2. Avoid segmentalisation if there is in adequate interdental space.

3. Start interdental osteotomy with bur and finish with osteotome to reduce

injury to lamina dura.

Oroantral and oronasal fistula

This usually follows a tear in palatal mucosa and in nasal mucosa. This occurs mainly in maxillary expansion with mid palatal procedures. Careful soft tissue handling will

minimise the complication . If such a communication does occur, the tissue is allowed to mature for 6-9 months , during this time defect can be covered with acrylic splints. Later closure using local flap can be considered.

Velopharyngeal incompetence

It is a rare complication can occur in patients with corrected cleft palate. This is caused by excessive anterior traction of soft palate in maxillary advancements. Pre-operative assessment can avoid such a problem.

Other rare complications

These include ophthalmic complications, vascular complications and avulsion of a segment.Vascular complications.

Ophthalmic Complications

This is a rare complication after Le fort I osteotomy this occurs mainly during pterygomaxillary disjunction. The ophthalmic complications of orthognathic surgery may be divided into 3 categories

1. Lacrimal system – Injury to the lacrimal system may lead to inability to tear or epiphora. The epiphora is usually transient and is due to surgical oedema.

2. Diplopia – This is due to abducens neuropraxia / paralysis secondary to propagation of pterygomaxillary disjunction fracture. The diplopia usually resolves in course of time.

3. Visual loss – This is an extremely rare complication.

CURRENT CONCEPT IN ORTHOGNATHIC SURGERY OF MAXILLA

Now the principle of distraction osteogenesis have been used for the advancement of maxilla in midface hypoplasia patients. After performing the osteotomy the maxillary segment is suspended to the zygomatic arch based distractor or to a halo frame fixed around the head. The maxilla is distracted slowly at the rate of 1mm per day. About 10 to 15 mm advancement is feasible by this process. The relapse tendency is minimal by this procedure. This distraction osteogenesis represents the new advances in bone regeneration and the fourth generation of grafting techniques in craniofacial surgery.

In the study conducted by Hans Peter .M. in Reversing segmental osteotomies of the upper jaw, mainly on patients which had undergone upper anterior segmental surgery 6 months to 10 year back. Most of the these patient came back with remark that they looked unduly aged because the lower part of the face was dished in. Author discussed the complications of the reverse osteotomies and in order to restore the old situation a new treatment plan is to be made.

In the study by M. R. Reinkingh, for the transverse stability of the Le Fort I Osteotomies a palatal surgical splint is made of a transpalatal stainless steel bar with acrylic abutment against the palatal surface of the molar and bicuspid tooth. It is rigid and renders excellent retention. It causes minimal patient discomfort, and oral hygiene is hardly compromised.

A study conducted by A. Stewar, A.M. M. Cance, D. R. James, J.P. Moss on three-dimensional nasal changes following maxillary advancement in cleft patients. Three dimensional laser surface, scanning of the face was performed before and after Le Fort I maxillary advancement in 24 patients with repaired clefts of the lip and palate. The surgery resulted in advancement of the upper lip and para-alar tissues and an increase in the relative prominence of the nose. These changes were produced at the expense of an increase in nasal width and a reduction in nasal tip protrusion. The changes is nasal morphology showed significant variation among patients.

In the study conducted by D. Bloomquist, D Baab, Y .B. Geylikman, J. Artun, B. G. Leroux evaluated the effect of Le Fort I osteotomy on human gingival and pulpal circulation. The maxillary blood flow during the first 24 and following Le fort I osteotomy was evaluated by Laser Doppler flowmetry. Pulpal blood flow was recorded from two maxillary incisors and gingival blood flow was assessed from a site slightly apical to the interdental papilla of the maxillary central incisors of 12 patients receiving Le Fort I osteotomy, nine control patients receiving mandibular osteotomy, and 10 non surgical control subjects with out orthodontic appliances. Measurements were made before surgery and at time intervals between 0-8, 8-16 and 16-24 hrs after surgery following surgery, men gingival (but not pulpal) blood flow significantly lower for patients treated with Le Fort-I osteotomy.

CONCLUSION

Orthognathic surgery has made it possible to reposition of either or both jaws in all possible directions. This has provided solution for the patients with severe dentofacial problems and malocclusion. Thorough evaluation and assessment of the defect and efficient execution of the surgery is needed for effective result. Use of more rectified technique, improvements in instruments especially the introduction of the fine oscillating and reciprocating saws has enabled the surgeon to precise. The development of new techniques like distraction osteogenesis have aided in reducing relapse after an maxillary advancement and the need for extensive surgery. Repeated assessment and rectification of the technique are required to improve the outcome of these aesthetic surgical procedures.

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