- Dr. Dona Bhattacharya

Surgical anatomy of maxillary sinus – note on OAF

Contents1. Introduction 2. Embryology of maxillary sinus3. Anatomy of maxillary sinus4. Vascularization & innervation5. Microscopic anatomy 6. Physiologic nature of mucus layer7. Drainage of sinus8. Functions of sinus9. Maxillary sinusitis10. Oroantral fistula11. Conclusion12. References

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 Orban’s

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

EmbryologyHorizontal shift of palatal shelves

and fusion with one another

Nasal septum separates 20 Oral cavity from nasal chambers

Influence expansion of lateral nasal wall and 3 walls begin to fold

3 conchae & meatus

Superior & inferior- Shallow depression

for half of IU Life

Middle- Expansion in lateral wall and in inferior

direction

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

a) 0-2.5 yearsb) 7.5-10 yearsc) 12-14 years

Embryology

0-3 years• Ovoid

appearance

• 7 mm x 4mm x 4mm volume 6-8 ml

• 5th month - pneumatization

• 20th month – posterior development

• 3rd year – ½ adult size

3-4 years• ↑ in width with

facial growth

• Position; 2nd deciduous molars and crypts of 1st permanent molars

• Prone to infections

7-9 years• Dimensions 27

mm x 18 mm x 17 mm

• Growth corresponding to permanent teeth eruption

• Canine present as ridge in anterior surface of sinus

Embryology

9-12 years• Antral floor

same level with nasal floor

• Portions of alveolar process vacated become pneumatized

• Assumes pyramidal shape

12-15 years• Floor of sinus

5–12.5 mm below nasal floor

• Dimensions 32-34 mm x 28-33 mm x 23-25 mm

• Volume 15-20 ml

• Floor i.r.t 1st and 2nd molars and 2nd premolar

Old age• Resorption of

ridge – thinning of sinus wall

• Extension of sinus till crest

• Anterior & infratemporal surface reverts to infantile condition

Embryology

Embryology

Developmental anomalies1. Agenesis 2. Aplasia3. Hypoplasia4. Supernumary maxillary sinus

AnatomyLargest of

PNS,communicate with other sinuses through lateral nasal wall.

Horizontal Pyramidal shaped

BaseApex4 walls

Wall thickness varies with individual

superior

inferior

lateralanterior

AnatomyVarious shapes

Hyperbolic-47% Paraboloid-30% Semi-ellipsoid-15% Cone shaped-8%

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

Vol:15-30 ml

AnatomyReceses-

Alveolar Zygomatic Palatal Frontal

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

Medial wallFormed by lat nasal wall

Below-inf nasal conchaeBehind-palatine boneAbove-uncinate process of ethmoid,lacrimal

bone

Contains double layer of mucous membrane(pars membranacea)

Medial wall

Imp structures Sinus ostium Hiatus semilunaris Ethmoidal bulla Uncinate process Infundibulum

Applied aspect

Natural ostiumLocated in posterior ½

of infundibulum or behind lower1/3 of uncinate process.

Tunnel shaped, length: 1-22mm;3-6mm diameter

Not detected endoscopically

Unfavorable position for gravity dependent drainage

Post edge-continuous with lamina papyracea(imp for surgical dissection)

Accessory ostium

2-3 in no.(30-40%)Bony dehiscences covered by

mucosa(ant/post frontanelles)

Superior wall

Forms roof of sinus and floor of orbitImp structures

Infraorbital canal Infraorbital foramen ASA nerve

Applied aspect Vulnerable to trauma Erosion of this wall by tumor

Posterolateral wallMade of zygomatic and greater wing of sphenoid

bone(maxillary tuberosity)Thick laterally,thin mediallyImp structures

PSA nerve Maxillary artery Maxillary nerve Pterygopalatine ganglion Nerve of pterygoid canal

Applied aspect Involvement of PSA-pain in post teeth Surgical 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 structures

Infraorbital foramenASA, MSA nervesLevator labii, obicularis oculi muscles

Applied aspect

Floor of sinusFormed by junction of anterior

sinus wall and lateral nasal wall

1-1.2 cm below nasal floor Close relationship between

sinus and teeth facilitate spread of pathology

Inner surface is rough by bony septaRetrieval of root fragment Interferes with sinus

drainage

Vascularization & innervation

Arterial Supply

a) Nasal Mucosal Vasculature

SP, Ethmoid

b) Osseous Vasculature

IO, PSA, ASA, GP, Facial

Venous Drainagea) Medial wall - SP

b) Other walls – Pterygomaxillary Plexus

Lymphatic Drainage Collecting vessels in middle meatus

Nerve Innervation ION, GP, PSA, MSA, ASA

Clinical significancePO2 of sinus = 116 mm Hg

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 other

All cilia beat together to form metachronous wave

Each cilia has power stroke followed by recovery stroke

Ciliated epithelium

Microvilli

Hair like projection of actin filament Length 1-2 mm Function:

Increase surface area of cellPrevent drying of surface

Physiologic nature of mucus layer

Sino nasal epithelium covered by mucus blanket

Traps particles>0.5-1 umComposition

Water (95%)Others (5 %)

Peptides Salts Debris

Ph = 5.5-6.5

Physiologic nature of mucus layer

2 layers

Inner sol- Continuous

- Low viscosity- Surrounds shafts of

cilia

Outer gel-Discontinuous- High viscosity

-Along ciliary tips

Drainage of sinus

Mucus transported from nose and PNS to nasopharynx, ingested and presented to GIT (Messerklinger)

Forms basis of fess

Drainage of sinus

Mucociliary flow from anterior sinuses converge at OMC, carried to posterior nasopharynx & inferiorly to eustachian

tube orifice

Mucus coursing along lateral wall, carried medially along roof to reach ostrium

Drainage into ethmoidal infumdibulum

Upward course along walls of entire cavity and then towards natural ostium in superomedial wall

Flow of mucus superiorly against gravity

By Donald et al & Antunes et al

Drainage of sinus

Drainage of sinusMucociliary flow Smooth:0.85 cm/minute

Jerky: 0.3 cm/minute

Mucostasis: <0.3 cm/minute

Basal lamina & subepithelium

Contains serous glands and blood vesselsSubepithelium – 10 serousMucosa removal – 73% decrease in serous

glands and 30% in goblet cells

Functions of sinus1. Decrease skull weight2. Impart resonance to voice3. Mucus production and storage4. Humidify and warm inhaled air5. Define facial contour6. Immunodefensive action7. Conserve heat from nasal fossae8. Moisturize air9. Filters debris10. Dampen pressure differential during inspiration11. Limit extent of facial injury from trauma12. Serves as accessory olfactory organ

Maxillary sinusitis

Group of diseases mainly inflammation & infection which affect the nasal mucosa and PNS

Maxillary sinusitis

Classification

According to duration

a) Acute: 7 days - 4 weekb) Subacute: 4-12 weekc) Chronic : > 12 weekd) Recurrent acute: 4 episodes per year

Presence/absence of

polyps/etiology

a) Bacterial b) Fungalc) Virald) Mycobacteriae) Parasite

Based on histological

markers

a) EO chronic hyperplasticb) EO chronicc) Non EO chronic hyperplasticd) Non EO chronic

Maxillary sinusitisAnatomical variations

influencing the development of sinusitis

a) Variations of uncinate process

b) Variations in bulla ethmoidalis

c) Variations of middle turbinate

d) Accessory ostium e) Deviated nasal septumf) Nasal masses g) Haller cell

Maxillary sinusitis

1. Infectious causesa) Bacterial b) Viral c) Fungald) Parasitic

2. Non infectious causesa) Allergicb) Non allergicc) Pharmocologic d) Irritants

3. Disruption of mucociliary drainagea) Surgeryb) Infectionc) Trauma

Extrinsic causes 1. Genetic

a) Structuralb) Immunodeficiencyc) Mucociliary abnormality(cystic fibrosis, dismotility)

2. Acquireda) Aspirin hypersensitivityb) Autonomic dysregulationc) Hormonal d) Structural (Tumors, cysts)e)Idiopathic/ autoimmunef) Immunodeficiency

Intrinsic causes

Maxillary sinusitisDiagnosis

1. History 2. Physical examination

Inspection Palpation Percussion Diagnostic techniques

a. Rhinoscopyb. Endoscopyc. Nasal valve

examinationd. Culture and sensitivity

Maxillary sinusitisMajor & Minor Factor Associated with the

Diagnosis of Chronic Rhinosinusitis

Major Factors Minor Factors

Facial pain/pressure Headache

Facial congestion/fullness

Fever (non-acute cases)

Nasal obstruction/blockage

Halitosis

Nasal discharge/purgulence/discolored postnasal discharge

Fatigue

Hyposmia/anosmia Dental pain

Purulence in nasal cavity on examination

Cough

Fever (in acute rhinosinusitis only)

Ear pain/pressure/fullness

Maxillary sinusitis3. Radiological examination

a) OM viewb) Caldwell viewc) Lateral viewd) CT scane) MRI

4. Tests for mucociliary functionsa) Nasomucociliary clearanceb) Ciliary beat frequencyc) NO measurementd) Rhinomanometry

5. Test for olfaction

Maxillary sinusitisManagement

Medical

1. Antibiotics2. Steroids3. Decongestants4. Analgesics5. Antihistamines6. Nasal spray & saline irrigation7. Hydration8. Mucolytics(guaifenesin,KI)

Surgical

1. sinus aspiration and lavage2. Maxillary needle sinusotomy3. Caldwell luc4. FESS

AntibioticsAntibiotic Micro factors Pediatric dosage

First line therapy

Amoxicillin45 mg/kg/day or 90 mg/kg/day divided

500 g BID

Second line therapy

Amoxicillin/potassium calvulanate

22.5-45 mg/kg/day divided (dose based on amoxicillin component)

500-875 mg BID

Azithromycin10 mg/kg/day on day 1, then 5 mg/kg/day on days 2-5

500 mg QID on day 1, then 250 mg QID on days 2-5

Cefdinir 14 mg/kg/day 300 mg BID

Cefpodoxime 10 mg/kg/QID 200 mg BID

Cefprozil 15 mg/kg/QID 250-500 mg BID

Cefuroxime 15 mg/kg/QID 250 mg BID

Ciprofloxacin 500 mg BID

Clarithromycin 7.5 mg/kg/day 500 mg BID

Cindamycin 8-20 mg/kg/day divided QID 150-450 mg BID

Doxycycline 100-200 mg QID

Garifloxacin 400 mg QID

Levofloxacin 500 mg QID

Sulfamethoxazole/trimethoprim

6-12 mg/kg/day divided (based on trimethoprim)

800-160 mg BID

Steroids

1st line of therapy: topical intranasal (betamethasone, dexamethasone, triamcinolone)

Systemic steroids: Prednisolone:0.5-1mg/kg x3-4 days

Decongestants

Systemic (phenylpropanolamine, pseudoephidrine):

Contraindications: hypertension, hyperthyroidism, asthma

Topical: phenylepinephrine HCl, oxymetazoline HCl

Adv. Effects- rhinitis medicamentosa

Analgesics & antihistamines

Analgesics: Opoid: acetaminophen, codeine NSAIDS:

Antihistamines: Mequitazine, terfenad Contraindicated in bacterial sinusitis Adv effect: sedation

Nasal lavage & sprays

m/a: Removes debris & dead tissue Washes inflammatory secretions Eliminates nutrient source

Methods: Lavage pot Syringe Irrigating bulb

Nasal lavage & sprays

Techniques of nasal sprays1. Moffet position2. Mygind technique

Surgical management

Indications

• Bilateral chronic sinusitis with polyps

• Fungal sinusitis• Presence of

complications• Tumor of PNS• Csf rhinorrhea

Contraindications

• Presence of extensive polyps

• Pt withc/c of headache and midfacial pain

• Medically compromised

• Hypoplastic sinuses

Sinus aspiration & lavageDirect removal of bacteria laden secretionsIndication: no response to medical therapyD/A

Maxillary needle sinusotomyd/a

Requires force to enter anterior wall

Alternatives: Mallet Steinmann pin

Complications: Bleeding Infection Dental injury Sensory nerve disturbance Instrument breakage

Infiltration of LA

Preparation of site

Transcutaneous puncture ant & post to canine eminence

Caldwell luc sinusotomyBy George Caldwell (1893) & Henry Luc (1897)Indications

Fungal sinusitis Multiple antral lesions Antrochoanal polyp Excision of tumor Closure of OAF Removal of antral foreign body Antral revision procedures surgical approach for transantral

sphenoethmoidectomy, orbital decompression

Caldwell luc sinusotomy

Caldwell luc sinusotomy

ModificationsComplications

Bleeding Dental sensitivity Infraorbital neuralgia Osseous defect in anterolateral wall Entrapment of inferior rectus muscle

FESSCoined by Kennedy

Intranasal endoscopic technique that allows establishment of adequate sinus drainage without negative impact on sinus mucosa physiology and function.

Principle: stop the cycle that begins with ostium blockage that leads to chronic sinusitis via stagnated secretions, tissue inflammation and bacterial infections.

FESSArmamentarium

FESS

FESS

Minor hemorrhageHyposmiaAdhesionsPeriorbital emphysema

Intracranial hemorrhageBrain injuryCSF leakDiplopiaBlindnessAnosmiaEpistaxisNL duct injuryMeningitis

Complications

SinusitisComplications:

Facial cellulitisOrbital

extensionIntracranial

extension

Oroantral fistulaFistular canal between oral cavity and

sinal mucous membrane covered with epithelium which may or may not be filled with granulation tissue or polyposis.

Duration and width of lumen contributes to infection of sinus.

OAC OAF(incidence: 0.3-3.8 %)

Oroantral fistula

OAC OAF Defect > 5mm diameter No approximation of gingival tissues Post op regime not followed Loss of clot or wound dehiscence Cyst enucleation Smoking, drinking

Oroantral fistulaEtiology

• Iatrogenic (50%)• Presence of periapical lesions• Injudicious use of instruments• During attempted extraction• Trauma(7.5%)• Chronic infections(11%)• Malignant diseases(18.5%)• Infected maxillary dentures(3.7%)• h/o sinus surgery(7.5%)

Oroantral fistulaPredisposing factors

• Proximity of sinus floor / tuberosity• Thickened tooth cement / tooth fused to jaw bone• Infected teeth / long-standing decay• Marked periodontitis / gum disease• Lone-standing• Previous history of OAC’s.

Oroantral fistula

Acute Chronic

1. Escape of air and fluids through nose & mouth

1.Pain, tenderness over cheeks

2. Epistaxis 2. Purulent discharge

3. Excruciating pain 3. Post nasal drip

4. Altered voice 4. Presence of polyps

5. h/o surgery in vicinity of sinus 5. Generalized constitutional symptoms

Common in males,2nd-3rd decade Immediate sign:

Displaced root /tooth Tuberosity #

Oroantral fistulaDiagnosis

h/o previous extractionValsavin testMouth mirror testCotton wisp testInspectionRadiological

IOPAOPGOM

Oroantral fistulaManagement

• 3mm-5mm heals spontaneously(HANAZANE)• Ideal treatment :immediate surgery followed by

Ab prophylaxis• Acute OAF: closure by simple reduction of

buccal and palatal socket walls, followed by acrylic splint.

• Treatment for small opening

Oroantral fistula

1) antibiotics : Pn & derivatives2) nasal decongestants:

Ephedrine dropsInhalations(steam,benzoin ,menthol)

3) Analgesics:Aspirin 500mgParacetamol 500mgIbuprofen 400 mg

4) Antral lavage

Oroantral fistulaAntral lavage

Oroantral fistulaWhitehead’s varnish

Oroantral fistula• Acrylic plates

Surgical closure

Closure of Oroantral Communications:A Review of the Literature, Susan H. Visscher et al, J  Oral Maxillofac Surg68:1384-1391, 2010

•Temporalis flap•Forehead flap

Overview of the treatment modalities of Oro-Antral Communications

Surgical closure

Factors determining flap selection Size of communication Timeline of diagnosing Presence of infection

Buccal flap• Advantages• Disadvantages• Modifications

• Moczaic• Laskin & Robinson

Palatal flap

Palatal pedicle flapA) Ito & Hara

modificationB) Island flap

Gullane & Arene modification

Combined flap

Distant flaps

BUCCAL FAT PAD

Tongue flap

Introduced by lexer,1909TechniqueAdvantagesDisadvantages

Grafts

GraftsGRAFTS

AUTOGENOUSIliac crestChinRetromolar areaZygoma

ALLOGENOUSCollagen sheetFibrin glueGold foilTantalumPMMAHydroxyapatite

XENOGRAFTSPorcine dermisBio guide & Bio oss

Sandwich Technique

Other techniques

Third 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)

Conclusion

Due 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.

References

• ECAB: 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

References

• Open 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

Thank You