Soft Tissue Changes Associated with Orthognathic Surgery

By David R. TellesDiplomate of the American Board of Oral and Maxillofacial SurgerySoft Tissue Changes Associated with Orthognathic Surgery

IntroductionOverviewOrthodontic considerationsMovement of dentitionMaxillary MovementsMandibular MovementsSurgical Techniques

IntroductionNecessary to include a component of soft tissue changes in the surgical treatment plan while working to achieve a stable, functional dentoskeletal unitthe surgical procedures -- to control the soft tissue changes will be presented and evaluated help the surgeon understand, control, and maximize the beneficial aspects of the facial soft tissue response to surgery.

HistoricallyOrthognatic surgery -- used to correct skeletofacial deformities and the resultant functional problems, often at the expense of the facial soft tissue estheticsEarly studies produced average ratios which related hard/soft tissue landmarksIndividual variability noted to be significantFacial soft tissue response to orthodontics and Sx was MultiFactorialPrediction equations developed to help preop evaluation for surgical planning and post-op assessmentRecent development of surgical procedures to control soft tissue response to Sx: alar cinch suture and VY closure

Orthodontic ConsiderationsTooth position and alveolar morphology result from the sum of applied forces during their developmentSkeletal imbalances are accompanied by soft tissue imblanaces result = dental compensation for skeletal malocclusionsCorrections initially result in worsening of the malocclusion preoperatively + jaw-jaw discrepency to appear more severePre-op records to be taken as close to Sx to determine soft-tissue outcome

Cephalometric ConsiderationsMust allow for visualization of the complete soft tissue profileInstruct pt to keep lips in repose for cephsSuperimpose landmarks that remain unchangedPresence of ortho hardware changes the lip profile

Cephalometric Landmarks

Soft Tissue ConsiderationsTo predict soft/hard tissue changes is critical to Tx planning for orthognathic SxChanges depending onsurgical proceduremethod of wound closurethe new spatial arrangement of the skeletal/dental elementsadaptive qualities of soft tissuesGrowthorthodontic vectors o ftooth movementlip thickness. tonus, area, contact (competence), strengthinterlabial gapamount of overjetamount offatty tissue Musculaturepostoperative edema.

Soft Tissue ConsiderationsStabilize in approx 6 months some studies suggest 12 monthsSurgical ApproachIncision type may play a role horizontal incision for the Le Fort I osteotomy may cause shortening of the lip With loss of vermillionDecrease in lip thicknessVertical approach with tunneling and palatal flap shows minimal post-op lip changesBetts et. Al. investigated soft tissue response to Max Sx found soft tissue changes may be more related to type/position of incision and method of closure than surgically induced hard tissue change

Soft Tissue ConsiderationsWill mirror changes in the bony foundation should relapse occurThin lips move more predictably than thick lipsdead space under the lip may absorb the first portion of a bony advancement before soft tissue affectedHorizontal Changes in soft tissue more predictable than vertical changesRelated to the stability of the hard tissue movements (less stable in vertical dimension)

Soft tissue assoc. Orthodontic tooth movement

Maxillary surgical proceduresMost are soft tissue changes manifested in:NasalLabial

Maxillary surgical procedures NasalAffects lower aspect of the nasal dorsumWidening of the alar base regardless of vector of movementShortening of the columellar/alar height shortening of the nasal tip projectionNasolabial angle decreases or remains constant Maxillary surgical procedures NasalSuperior movementElevation of the nasal tipWidening of the alar baseDecreased nasolabial angleInferior repositioningLoss of nasal tip supportDownward movement of columella and alar basesThinning of the lipIncrease in NL angle

Maxillary surgical procedures NasalAnteriorAdvancement in the upper lipSubnasalePronasaleThinning of the lipWidening of the Alar baseIncrease in Supratip break if ANS in tact***Nasal tip advances approx the distance of the subnasale*******Counter clockwise rotation raises the nasal tipClockwise rotation decreases superior movement of the nasal tip

Maxillary surgical procedures Nasal

Maxillary surgical procedures LabialUpper lip is attached to the nose prevents 1:1 soft tissue changeWidens and lengthens at the philtral columns after Max Sxw/o VY closure can cause shorteningof the upper lip with loss of exposedvermillion

Maxillary AdvancementGreatest effect on the nose/upper lipPpts adv of upperlip, subnasale and noseShortening of upper lipThinning of upper lip (approx. 2 mm)Widening of Alar baseDeepening of supratip depression if ANS left intactProgressive increase in horizontal soft tissue displacement seen from tip of nose to free end of upper lipDecrease in NL angle

Maxillary Advancement Carlotti et. al. determined that the ratio of horizontal change of upper incision to vermillion border of the upper lip with use of the alar cinch suture and the VY closure The ratio reduces with larger advancements due to soft tissue stretching: 0.6:1 vs. 0.9:1

Maxillary Advancement

Maxillary Impaction superior Elevation of nasal tipWidening of alar base (2-4 mm)Decrease in NL angleNasal changes occur w/o changes in angulation of upper lipLip follows superiorly approx 40% of the vertical maxillary planeLip shortening accentuated with combined anterior/superior max movementsIf no VY amnt of vertical soft tissue change increases progressively from nasal lip to stomion with loss of vermillion

Maxillary Impaction

Maxillary inferior repositioningLoss of nasal tip supportDownward repositioning of the columella and alar basesThinning of the lipIncrease NL angle

Maxillary posterior repositioningLoss of nasal tip support- due to movement of ANS- movement of bony area around piriform apertureLip rotationPosterior and superiorly about SubNasaleIncreased NL angleMaxillary Setback

Multi-direction Maxillary movements

Mandibular surgical proceduresGenerally soft tissues follow hard tissues closely Exception is lower lipTypes of movementsAnteriorPosteriorAnterior segmentalAutorotationGenial Segmental proceduresMandibular surgical procedures - anteriorMandibular AdvancementLimited to the structures below the superior labial sulcusLittle change in the upper lip and none above the ANSLower lip advancement is variable and lip often lengthensLower labial sulcus and chin adhere to the bony structure and follow underlying osseous structuresLeads to opening of labio-mental fold

Mandibular surgical procedures - anteriorMandibular AdvancementFacial HeightIn high angle II cases results in large increase in FHLower lip positionAffected by upper, lower incision and its contact with the upper lipIn class II lower lip may touch the upper lip/incisor and fold forward correction of this is necessary to approximate true post-op position

Mandibular advancement

Mandibular surgical procedures - PosteriorMandibular SetbackNo net effects on subnasale or tissues superior to itSoft tissues follow mandible posteiorlyChin most closely Lower lipShortensMore protrusive and curls outLabiomental fold deepens + becomes more acute

Mandibular Setback

Mandibular surgical proceduresAnterior Segmental Osteotomy

Mandibular Surgical Procedures -- autorotationSoft tissues follow the osseous landmarks approx 1:1 Except lower lip falls slightly lingual to the arc of rotation

Mandibular Surgical Procedures -- GenioplastyAnterior

Mandibular Surgical Procedures -- GenioplastyPosterior -- setback

Mandibular Surgical procedures Vertical Augmentation/reduction GenioSoft tissues follow hard tissues very closely in augmentation genio compared to reduction

Controlling Soft Tissue Poor Surgical ResultsSurgical TechniquesVY closureCinch Suturing Figure 8 techniqueDual alar cinch sutureContouring ANSDouble VY closureBilateral alar base wedge resection SeptoplastyAdvancement genioplasty / liposuction excess submental adipose tissue and/or short cervicomental distance

Controlling Soft Tissue

Controlling Soft Tissue

Controlling Soft TissueVY closure

Controlling Soft TissueCinch Suture figure 8

Controlling Soft TissueDual Alar cinch Suture

Controlling Soft TissueContouring of ANS

Controlling Soft TissueDouble VY

Controlling Soft TissueBilateral Alar Base wedge resection

Controlling Soft TissueSeptoplastyCartilagenous septum should be reduced during maxillary impactions of > 3 mm to prevent post-op deviationAvoid over reduction as it can cause saddle nose deformity or poly-beak deformity