Surgical anatomy of maxillary sinus note on OAF

- Dr. Dona BhattacharyaSurgical anatomy of maxillary sinus note on OAF

ContentsIntroduction Embryology of maxillary sinusAnatomy of maxillary sinusVascularization & innervationMicroscopic anatomy Physiologic nature of mucus layerDrainage of sinusFunctions of sinusMaxillary sinusitisOroantral fistulaConclusionReferences

IntroductionParanasal sinuses Air containing bony spaces present around the nasal cavity

Usually lined by respiratory mucus membrane

Four paired

Maxillary sinusPneumatic space lodged in the body of maxilla that communicates with the external environment by way of middle meatus and nasal vestibule - by Orbans

Also known as antrum of Highmore (1651)

EmbryologyFirst sinus to develop

Initial development of sinus follows number of morphogenic events in differentiation of nasal cavity

Embryology

EmbryologyDevelopment of sinus begins as evagination of mucus membrane in lateral wall of middle meatus when nasal epithelium invades maxillary mesenchyme ( Kitamura, 1989)

Growth of sinus takes place by pneumatization Primary (10th weeks) Secondary (5th month)

EmbryologyMaxillary sinus has biphasic growth 0-3 years and 7-12 yearsPost natally grows @ 2 mm vertically and 3 mm AP Radiographically; triangular area medial to IOF (5th month)3 growth spurts 0-2.5 years7.5-10 years12-14 years

Embryology

Embryology

Embryology

EmbryologyDevelopmental anomaliesAgenesis AplasiaHypoplasiaSupernumary maxillary sinus

AnatomyLargest of PNS,communicate with other sinuses through lateral nasal wall.Horizontal Pyramidal shapedBaseApex4 walls

Wall thickness varies with individualsuperiorinferiorlateralanterior

AnatomyVarious shapesHyperbolic-47%Paraboloid-30%Semi-ellipsoid-15%Cone shaped-8%

Dimensions (Therner, 1902)H: 3.5cm W: 2.5cmL: 3.25cm

Vol:15-30 ml

AnatomyReceses-AlveolarZygomaticPalatalFrontal

Teeth in proximity 2nd, 1st , molar>3rd molar>2nd pm>1st pm>canine

Medial wallFormed by lat nasal wallBelow-inf nasal conchaeBehind-palatine boneAbove-uncinate process of ethmoid,lacrimal bone

Contains double layer of mucous membrane(pars membranacea)

Medial wallImp structures Sinus ostiumHiatus semilunarisEthmoidal bullaUncinate processInfundibulum

Applied aspect

Natural ostiumLocated in posterior of infundibulum or behind lower1/3 of uncinate process.Tunnel shaped, length: 1-22mm;3-6mm diameterNot detected endoscopicallyUnfavorable position for gravity dependent drainagePost edge-continuous with lamina papyracea(imp for surgical dissection)

Accessory ostium2-3 in no.(30-40%)Bony dehiscences covered by mucosa(ant/post frontanelles)

Superior wallForms roof of sinus and floor of orbitImp structuresInfraorbital canalInfraorbital foramenASA nerve

Applied aspectVulnerable to traumaErosion of this wall by tumor

Posterolateral wallMade of zygomatic and greater wing of sphenoid bone(maxillary tuberosity)Thick laterally,thin mediallyImp structuresPSA nerveMaxillary artery Maxillary nervePterygopalatine ganglionNerve of pterygoid canal

Applied aspectInvolvement of PSA-pain in post teethSurgical access by careful removal of segment of wall

Anterior wallExtends from pyriform aperture anteriorly to ZM suture & IO rim superiorly to alveolar process inferiorly.Convexity towards sinusThinnest in canine fossaImp structuresInfraorbital foramenASA, MSA nervesLevator labii, obicularis oculi musclesApplied aspect

Floor of sinusFormed by junction of anterior sinus wall and lateral nasal wall1-1.2 cm below nasal floor Close relationship between sinus and teeth facilitate spread of pathologyInner surface is rough by bony septaRetrieval of root fragment Interferes with sinus drainage

Vascularization & innervation Arterial SupplyNasal Mucosal Vasculature

SP, Ethmoidb) Osseous Vasculature

IO, PSA, ASA, GP, FacialVenous Drainagea) Medial wall - SPb) Other walls Pterygomaxillary PlexusLymphatic DrainageCollecting vessels in middle meatusNerve Innervation ION, GP, PSA, MSA, ASA

Clinical significancePO2 of sinus = 116 mm Hg

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Vascularization & innervation

Microscopic anatomy3 layers EpitheliumBasal laminaSub epithelium

EpitheliumPseudostratified columnar ciliated epithelium Cells Columnar ciliated Goblet BasalNon ciliated

Ciliated epithelium100 motile and no. of immotile microvilli present along apical surfaceFunction: mucus clearance along with entrapped debris from nose and PNSCiliary motility dependent on ATP driven molecular motors cause outer doublets of axoneme to slide over each otherAll cilia beat together to form metachronous waveEach cilia has power stroke followed by recovery stroke

Ciliated epithelium

MicrovilliHair like projection of actin filament Length 1-2 mm Function: Increase surface area of cellPrevent drying of surface

Physiologic nature of mucus layerSino nasal epithelium covered by mucus blanket Traps particles>0.5-1 umComposition Water (95%)Others (5 %)PeptidesSaltsDebrisPh = 5.5-6.5

Physiologic nature of mucus layer

Drainage of sinusMucus transported from nose and PNS to nasopharynx, ingested and presented to GIT (Messerklinger)Forms basis of fess

Drainage of sinusBy Donald et al & Antunes et al

Drainage of sinus

Drainage of sinusMucociliary flow

Smooth:0.85 cm/minuteJerky: 0.3 cm/minuteMucostasis: 5mm diameterNo approximation of gingival tissuesPost op regime not followedLoss of clot or wound dehiscenceCyst enucleationSmoking, drinking

Oroantral fistulaEtiologyIatrogenic (50%)Presence of periapical lesionsInjudicious use of instrumentsDuring attempted extractionTrauma(7.5%)Chronic infections(11%)Malignant diseases(18.5%)Infected maxillary dentures(3.7%)h/o sinus surgery(7.5%)

Oroantral fistulaPredisposing factors

Proximityofsinusfloor/tuberosityThickened toothcement /tooth fused to jaw boneInfected teeth/ long-standingdecayMarkedperiodontitis/gum diseaseLone-standingPrevious history ofOACs.

Oroantral fistulaAcuteChronic1. Escape of air and fluids through nose & mouth1.Pain, tenderness over cheeks2. Epistaxis2. Purulent discharge3. Excruciating pain3. Post nasal drip4. Altered voice4. Presence of polyps5. h/o surgery in vicinity of sinus5. Generalized constitutional symptoms

Common in males,2nd-3rd decadeImmediate sign:Displaced root /toothTuberosity #

Oroantral fistulaDiagnosish/o previous extractionValsavin testMouth mirror testCotton wisp testInspectionRadiologicalIOPAOPGOM

Oroantral fistulaManagement 3mm-5mm heals spontaneously(HANAZANE)Ideal treatment :immediate surgery followed by Ab prophylaxisAcute OAF: closure by simple reduction of buccal and palatal socket walls, followed by acrylic splint.Treatment for small opening

Oroantral fistula1) antibiotics : Pn & derivatives2) nasal decongestants:Ephedrine dropsInhalations(steam,benzoin ,menthol)3) Analgesics:Aspirin 500mgParacetamol 500mgIbuprofen 400 mg4)Antral lavage

Oroantral fistulaAntral lavage

Oroantral fistulaWhiteheads varnish

Oroantral fistula

Acrylic plates

Surgical closure

Closure of Oroantral Communications:A Review of the Literature, Susan H. Visscher et al, JOral Maxillofac Surg68:1384-1391, 2010 Temporalis flapForehead flapOverview of the treatment modalities of Oro-Antral Communications

Surgical closureFactors determining flap selectionSize of communicationTimeline of diagnosingPresence of infection

Buccal flap

AdvantagesDisadvantagesModificationsMoczaicLaskin & Robinson

Palatal flap

Palatal pedicle flapIto & Hara modificationIsland flapGullane & Arene modification

Combined flap

Distant flaps

BUCCAL FAT PAD

Tongue flap

Introduced by lexer,1909TechniqueAdvantagesDisadvantages

Grafts

Grafts

GRAFTSAUTOGENOUSIliac crestChinRetromolar areaZygomaALLOGENOUSCollagen sheetFibrin glueGold foilTantalumPMMAHydroxyapatiteXENOGRAFTSPorcine dermisBio guide & Bio oss

Sandwich Technique

Other techniquesThird molar transplantation(kitagawa et al)Interseptal alveolotomy(hori et al)GTR(Waldrop & Semba)Prolamine gel(Gotzfried & Kaduk)Laser light(Janas)Splints for immunocompromised pts(llogan and coates)

ConclusionDue to close proximity of maxillary sinus to orbit, alveolar ridge, maxillary teeth, diseases involving these structures may produce confusing symptoms. Hence a precise information about the surgical anatomy is essential to surgeons.

The oroantral fistula is a problem that requires detailed attention to the management of a flap in the mouth. For the sake of obtaining the best results and to give the patient the benefit , proper knowledge about the different types of modalities and their limitations is necessary.

ReferencesECAB: Clinical update-otorhinolaryngology-Paranasal sinuses and rhinosinusitis-V.P Sood

OMFSClinics of North America-Diagnosis & treatment of disorders of maxillary sinus-Laskin

Principles of oral and maxillofacial surgery-Peterson

Textbook of oral and maxillofacial surgery-Killey and kay

Maxillary sinus and its dental implications:dental practice handbook-Killey and Kay

Review of oral and maxillofacial surgery-Ghosh

ReferencesOpen access atlas of otolaryngology, head & neck operative surgery -johan fagan

Treatment of Oroantral Fistula-Klara Sokler et al, Acta Stomatol Croat, Vol. 36, br. 1, 2002

Oronasal fistula closure by tongue flap-Manimaran K et al, JIADS,Jan-mar 2011

A New Surgical Management for Oro-antral Communication,The Resorbable Guided Tissue Regeneration Membrane Bone Substitute Sandwich Technique-C Ogunsalu, West Indian Med J 2005; 54 (4): 261

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