ORBIT IN ENT

INTRODUCTION

ORBIT - interface between ENT & Eye

specialist

Surrounded by PNS on 3 sides

Infection, inflammation & neoplasia can

spread in either direction

Relationship heightened by advent of ESS

SURGICAL ANATOMY

Orbit: Quadrilateral

pyramid

Relationships: Sup: Med: Inf: Lat: Apex:

SURGICAL ANATOMY Orbit:

Avg vol of 30 ml Fixed bony cavity Contains:

Globe Intraconal space Muscle cone Extraconal space

Medial wall: 5 inch long

From ant lacrimal crest to body of sphenoid & optic canal

Lacrimal fossa: antero medial Foramen for AEA, PEA & Optic N

Frontoethmoid suture ‘Rule of 24-12-6’ Rough indication: crib. plate

16% lack AEA foramen 30% multiple 4.6% none

Poor anatomical barrier

Inferior wall/ Floor of orbit: Consists of 3 bones

Orbital plate of maxilla, zygoma, palatine bone Floor is thin: 0.5 to 1.0mm

Infraorbital foramen: Halfway along inf rimContinuous with Infraorbital canal 25 mm from post wall of maxilla Damage due to trauma or surgery, Medial maxillectomy

Superior wall: Triangular 2 bones:

Orbital plate of frontal Lesser wing of sphenoid Thin: <3mm

Onodi cells: Supra-orbital notch & Frontal

notch Trochlea: connective tissue

sling Anchors tendinous part of Superior

Oblique muscle to orbit Fovea for trochlea: small

depression in superomed orbital margin

Lateral wall:

5 cm long 3 bones:

Orbital surface of Zygoma Marginal tubercle of Whitnall

Greater wing of Sphenoid Zygomatic process of

frontal Superior Orbital fissure

Optic N lies 8 mm behind it

Syndromes:

Lacrimal Apparatus Lacrimal gland ( Serous gland )

Parts: Orbital & Palpebral 12-15 ducts

Lacrimal sac: Apparatus to remove excess tears

Lacrimal cannaliculi: Flap valves of mucous membrane

Naso Lacrimal Duct: 2cm long & 3.5mm Mucous membrane folds Valve of Hasner

Periorbita:

Orbital perisoteum: Adherent to to orbital margin, sutures, foramen & fissures

and lacrimal fossa Continuous with dura thro’ sup orb fissure, optic canal,

ethmoidal canal Encloses lacrimal gland & surrounds NLD upto Inf Meatus Importance:

Protects the orbital contents Resists spread of infection & malignancy

Periorbita: Orbital septum:

Attached to ant lacr crest & margin of orbit Palpebral fissure Thickened at sup & inf margin: Tarsal Plate Medial Palpebral ligament

Preseptal & Pretarsal head of orbicularis oculi ms Superficial heads attach to ant lacr crest Deep heads attach to post lacr crest Together compress sac on blinking Detachment of MCL rounding of Medial canthus,

Telecanthus

Periorbita:

Orbital septum: Lateral palpebral ligament:

Thinner Fuses with lateral palpebral raphe of orbicularis oculi Attach at Marginal tubercle of Whitnall

Fascia Bulbi (Tenon’s Capsule): Thin membrane from corneoscleral junction to optic N Medial(MR ms) & Lateral(LR ms) check ligament Suspensory ligament of Lockwood inferiorly Stability of eye : Total Maxillectomy

Extra Ocular Muscle All ms arise from the

common tendinous ring (Annulus of Zinn at orbital apex) except Inferior oblique

Inferior oblique arises from the periosteum of maxilla

LR6 SO4 Rest3

SURGICAL ANATOMY Arterial supply

Ophthalmic artery Ocular branch: CRA, ciliary artery, br to optic n Orbital branch: lacrimal, muscular & periosteal branch Extraorbital br: AEA, PEA, Supraorbital A, Medial palpebral A,

Dorsal nasal A & Frontal A Infraorbital artery

Venous drainage: Superior Ophthalmic vn Cavernous sinus Inferior Ophthalmic vn Cavernous sinus & Pterygoid

plexus Lymphatics: NIL

SURGICAL ANATOMY Nerve Supply:

Enter via Superior orbital fissure & optic canal CN II, III, IV, V, VI

Changes with age:

Growth with facial skeleton Initially:

Large orbital fissure High orbital index Infraorbital foramen not fully formed

Little change after 7 yrs Advancing age:

Resorption of bone widening of fissures Female orbit: more elongated & larger

RADIOLOGY Plain X-Ray:

Adjacent sinus ds Orbital floor # Metallic Foreign body

Ultrasound: Good for lesion within globe FB in orbit Poor penetration

RADIOLOGY CT scan:

Axial & coronal Investigation of

choice Adv:

Readily available Fast & versatile Bone detail &

calcification Spatial resolution

Disadvantage: Radiation induced

cataract Artefact from dental

filling

RADIOLOGY MRI scan:

Usually when CT doubtful

Graves ophthalmopathy

IC complications Adv:

Better for optic n lesions No radiation

Disadvantage: Time consuming Metallic FB Poor resolution

Carotid angiography Vasular tumors &

malformations Invasive Time consuming

Orbital venography Dacrocystogram CT / MRI dacrocystogrpahy

A. SINONASAL PATHOLOGY OF ORBIT

I. INFECTION AND INFLAMMATION: Variety of infective & inflammatory condition

Orbital complication of sinusitis

Mucocoele

Polyposis

I. Infection & Inflammation

Orbital complications: Uncommon now-a-days Source Route of spread 1970, Chandler, Langenbrunner &

Stevens Preseptal cellulitis Orbital cellulitis without abscess Orbital cellulitis with extra periosteal

abscess Orbital cellulitis with intra periosteal

abscess Cavernous Sinus Thrombosis

II. Mucocoele Definition: Most commonly:Frontoethmoid

sinus’ Only 4% bilateral 40-70 yrs M>F Theories:

Pressure erosion Cystic degeneration Active bone resorption & formation

Slow expansion rapid if infected

II. Mucocoele

Initial ophthalmic referral Clinical features:

Proptosis: 90% Diplopia: 95% Displacement of globe: 55% Limited ocular movt. : 55% Visual impairment: 10% Mass, epiphora, Others:

Nasal Endoscopy:

II. Mucocoele

Investigation: Plain Xray

CECT- PNS

MRI

CECT PNS

FRONTAL MUCOCOELE BILOCULATED ETHMOID MUCOCOELE

26

Homogenous smooth walled mass expanding the sinus

MRI

ENHANCING ETHMOID MUCOPYOCOELE

NON ENHANCING MAXILLARY MUCOCOELE

27

II. Mucocoele

Treatment: Goals

Eradication of disease Minimal morbidity Prevention of recurrence

Endoscopic Osteoplastic flap Ext. Frontoethmoidectomy Combined

III. Chronic dacrocystitis Presents with epiphora &

swelling Etiology:

Idiopathic Trauma Malignancy Granulomatous disease

Incidence: 10% @ 40 yrs 40% @ 90 yrs

Assessment: Syringing & probing Nasal endoscopy Imaging

III. Chronic dacrocystitis Indication for surgery

Symptomatic distal obstruction of NLD not relieved by syringing & probing

Functional obstruction Combined proximal & distal obstruction

Methods: External DCR Conventinal endonasal DCR Endonasal Laser assisted DCR

Antimitotic agents: decrease fibrosis Mitomycin-C: 0.2mg/ml x 30 min 5-FU: 0.5mg/ml x 5 min

B. ORBITAL DECOMPRESSION

Finite capacity of orbit increased volume anterior displacement of orbital contents

Indication: Graves ophthalmopathy Retro-orbital hematoma Orbital abscess Pseudotumor Orbital infiltration by Wegeners Granulomatosis Foreign body Neoplasia : Benign or malignant or metastatic deposits Vascular causes

B. ORBITAL DECOMPRESSION

Approach: Single Wall Endoscopic Combined

Transantral + Endoscopic: 3 walled decompression:

Lower lid swinging flap: Horizontal canthotomy & Inferior cantholysis

Removal of lateral wall Removal of medial wall & floor of orbit

ENDOSCOPIC

DECOMPRESSIONTHREE WALLED DECOMPRESSION OF RIGHT

EYE

C. OPTIC NERVE DECOMPRESSION Indication:

Trauma: direct or indirect Thyroid eye disease Neoplastic compression of nerve eg Meningioma Chronic inflammation + fibrosis

Wegener’s Granulomatosis Radiation neuritis

Irreversible damage after 90 mins Alternative treatment: steroids in high doses

C. OPTIC NERVE DECOMPRESSION

Approaches: External:

Superior: external frontoethmoidectomy Lateral Medial: Extracranial Transnasal Endoscopic Combined

Extracranial transnasal endoscopic Ophthalmic artery may lie in inferomedial quadrant : 15%

Craniofacial approach Decompression upto optic chiasma Indication: More extensive or bilateral decompression

D. TRAUMA TO ORBIT

ETIOLOGY: Part of Mid Facial Injury Complication of ESS

I. Facial trauma involving orbit Blow out # of orbital floor/

medial wall Tripod # Naso-Orbito-Ethmoid

complex # Mechanism of injury:

Clinical Features: Blow out #:

Restriction of upward gaze Infraorbital anesthesia

Tripod # Flattening of orbital rim Inferior displacement of lat canthus Ecchymosis of buccal mucosa, trismus

NOE complex #: Flattening of nasal root Disruption of med canthus Telecanthus

Others: Visual complaints, Epistaxis, CSF leak, Enophthalmos/

Exophthalmos Malocclusion, Ecchymosis, Epiphora

Imaging

CT Facial bones (most

useful) ‘Tear Drop’ sign in blow out #

Plain Films of limited use Demonstrate # in 70%

MRI if retinal, optic nerve, or

intracranial concerns

Indications for Repair in Blow out # Entrapment that causes an oculocardiac reflex

with resultant bradycardia and cardiovascular instability

Relative enophthalmos greater than 2mm Fracture that involves greater than 50% of the

orbital floor (most of these will lead to significant enophthalmos when the edema resolves)

Diplopia that persists beyond 7 to 10 days Obvious signs of entrapment Progressive V2 numbness

Access: Fronto-Zygomatic area:

Lateral brow incision Lateral upper lid incision

Lateral rim: Lower lid conjuctival incision +

canthotomy Orbital floor:

Transconjuctival incision +/- lateral canthotomy

Transcutaneous incision Subciliary, Lower lid crease, Infraorbital

Access to Floor # Transantral Transnasal endoscopic

Access to Medial wall #: Lynch Howarth Transcaruncular

Materials for repair Autogenous bone/cartilage: Calvarial

bone, iliac crest, rib, septal or auricular cartilage

Alloplastic: Gelfilm, polygalactin film, marlex mesh, teflon, prolene, polyethylene, hydroxyapatite, silastic sheet, titanium

Miniplates

Collapse of Anterior wall of maxilla or Orbital floor fracture

Endoscopic ballon catheter repair: Wide MMA Insert Foley and inflate Leave in place for 7-10 days Best for large trapdoor fractures

without entrapment Broad spectrum antibiotics

TRAUMA TO ORBIT

II. Iatrogenic Orbital Trauma: Most commonly due to ESS Risk factors:

Distorted anatomy Anatomical variants: preop CT scan useful Higher incidence with GA: No pain

Prevention: Eyes uncovered During uncinectomy sickle knife angled away from globe ? Periosteum incised gentle pressure on globe Prolapsed fat reposition + gelatin foam, avoid nose blowing x

14days Tissues placed in NS

II. Iatrogenic Orbital Trauma: ESS:

MMA damage to NLDepiphora Ethmoidectomy damage to AEA retro-orbital hemorrhage Onidi cells damage to optic nerve(6% bone dehiscent) diminished

vision Caldwell Luc:

Damage to infra-orbital nerve Lynch Howarth external ethmoidectomomy approach:

Damage to trochlea Superior oblique underaction Patterson’s approach:

Damage to NLD Detachment of Inferior oblique & Medial canthal ligament

NLD can also be damage in Lat Rhinotomy & Cranio-Facial resection

E. Neoplasia

Wide variety of benign & malignant neoplasia

may spread to orbit from adjacent structures

+/- remove eyes psychological issues Preservation of eye

Emotional decision

Should not jeopardize prognosis

Consider the functional capacity of eye

Complicated by combined radiotherapy cataract, retinal

atrophy

I. Benign Tumors:

Angiofibroma: Young males Arise from sphenopalatine foramen Presents in nose & nasopharynx as a vascular tumor Spread PPF & ITF Infraorbital fissure & orbital

apex compress optic n visual loss MRI: Salt & pepper appearance Treatment:

Preop embolization Complete excision of tumor

I. Benign Tumors: Inverted Papilloma:

Intermediate tumor arising in lateral wall of nose Spreads extraperiosteally to orbit

Invasive consider associated SCC Treatment :

Medial maxillectomy Endoscopic resection High recurrence rate Imaging follow up

Osteoma: Arise in frontoethmoid region encroach orbit Proptosis Treatment if symptomatic Craniotomy via coronal incision

II. Malignant Tumors:

Tumors of sinonasal regions can invade orbit Invasion from ethmoids occurs early: Visual

symptoms & epiphora Routes:

Thin lamina payracea Can spread extraperiosteally to orbital apex & MCF

Foramen Perineural spread: Adenoid cystic CA

Meningioma involving sphenoid: B/l optic canal compression

II. Malignant Tumors:

Orbital perisoteum is resistant to tumor spread Once breached orbital contents cannot be salvaged

If orbital clearance required lids are preserved

II. Malignant Tumors:

Clinical features suggestive of orbital involvement: Visual complaints Diplopia Proptosis Unilateral epiphora Features of cranial nerves involvement:

ophthalmoplegia Rounding of orbital margin

Investigations Nasal endoscopy Imaging: CECT: coronal and axial images

Erosion and involvement of skull base Critical areas: fovea, cribriform plate, posterior wall of

maxillary sinus, optic foramen, medial orbit and sphenoid sinus

MRI with contrast: Flow voids: Vascularity Orbital invasion Soft tissue extension in deep face, intracranial

compartment

II. Malignant Tumors

Treatment options: Palliative:

Painful blind eye with proptosis orbital clearance Orbital exentration

Tumors involving skin of medial canthus Lateral orbitotomy

Extensive lesion of lateral portion of orbit And or extending to Anterior Cranial Fossa Removal of lateral rim: frontal + zygoma + supraorbital margin

Treatment options:

Maxillectomy Total maxillectomy Extended

maxillectomy Access to orbital apex

Medial Maxillectomy Lateral rhinotomy

incision + Medial canthal ligament

transected & tagged Lacrimal Sac mobilized

& Lacrimal duct transected

AEA & PEA identified & cauterized (bipolar)

Medial Maxillectomy

Osteotomy 1: vertically thro’ Ant margin of

medial wall 2: horizontally along inferior

aspect of medial maxillary sinus wall

3: thro’ medial wall of orbit just inferior to fronto-ethmoid suture

4: thro’ orbital floor medial to infra-orb canal

5: posteriorly thro’ posterior aspect of medial maxillary wall at Pterygomaxillary fissure

Optic foramen

Infra orbital canal & foramen

1

3

2

4

Total Maxillectomy:Incisions

Total Maxillectomy: Bony Cuts

Inf Orbital Fissure

Premaxilla and Anterior Alveolar Arch Preserved

Total Maxillectomy: Bony cuts

Naso maxillary suture

Pterygoid plates separated from post sinus wall

Horizontal cut if back wall of sinus involved

II. Malignant Tumors

Rehabilitation: Orbital prosthesis

Attached to spectacles

Adhesive glue

Osseointegrated titanium implants

If RT given : Prosthesis after 6 months

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