POST TRAUMATIC ENOPHTHALMOS AND HYPOGLOBUS – ASSESSMENT AND MANAGEMENT STRATEGIES

DR. OMER SEFVAN JANJUARESIDENT ORAL AND MAXILLOFACIAL SURGERY

ARMED FORCES INSTITUTE OF DENTISTRYRAWALPINDI

APPLIED SURGICAL ANATOMY• Orbit can be viewed as a pyramid with base anteriorly

and apex posteriorly• Composed of seven bones

FrontalZygomaMaxillaLacrimalEthmoidSphenoidPalatine

• Orbital volume 30-35cc and volume of globe is 7cc• Medial walls parallel and lateral wall divergent at 450

APPLIED SURGICAL ANATOMY

ORBITAL SEPTUM:Fascial continuation of periosteum and separates orbital contents from the lids

ORBITAL MUSCLES:• Orbicularis oculi• Levator palpebrae superioris• Recti• Superior oblique• Inferior oblique• Medial and lateral canthal tendons

APPLIED SURGICAL ANATOMYa) ARTERIAL SUPPLY:

Branches of ophthalmic artery (branch of ICA)b) VENOUS DRAINAGE:

Superior and inferior ophthalmic veinsc) NERVE SUPPLY:i) Sensory:

Optic nerveOphthalmic nerve

ii) Motor nerves:Abducent nerveOculomotor nerveTrochlear nerve

IMPORTANT SURGICAL LANDMARKS• Inferior orbital fissure 20mm from rim• Superior orbital fissure 35 from FZ• Anterior ethmoidal foramen 24mm from rim• Posterior ethmoidal foramen 12mm from Anterior ethmoidal foramen• Optic canal 42mm from anterior lacrimal crest

45mm from inferior orbital rim45mm from supra-orbital notch6mm from posterior ethmoidal foramen

• FZ suture 1cm above the outer canthus• Dissections can be carried out 35mm within the orbit safely

These distances are in intact adult orbits, they can be different in traumatic events and pediatric patients !!

ENOPHTHALMOS • Retro positioning of the globe in its three dimensional

relationship in the orbit

• Should always be assessed in relation to the contra-lateral eye

• It is an unsightly deformity which can be impossible to correct completely

• Regarded as the most common and serious sequalae of complex orbital trauma.

SIGNS AND SYMPTOMS• Sunken eye

• Narrowing of palpebral width with pseudo-ptosis of the

upper lid

• Supra tarsal hollowing

• Hooding of the eye

• Decreased anterior projection of the globe

• Lid retraction of the opposite eye

• Paresthesia of the infraorbital nerve

CLASSIFICATION a) SIMPLE:

Due to abnormal bony position

b) ENOPHTHALMOS WITH DIPLOPIA:Due to bony and soft tissue insult

c) CICATRICIAL:Severe restriction of eye movements due to

extensive scarring

d) SECONDARY TO FAT ATROPHY

CATEGORIES

• No enophthalmos

• Mild enophthalmos <2mm

• Moderate enophthalmos 3-4mm

• Severe enopthalmos >4mm

CAUSES • Increased orbital volume• Herniation of orbital fat• Orbital fat atrophy• Loss of ligamentary support• Scar contracture• Trochlear dislocation• Entrapment of tissues in blow outs pulls the whole

system downwards and backwards• Action of gravity on orbital contents in an enlarged

cavity • Resolving hemorrhage and edema

RELATIONSHIP WITH ORBITAL VOLUME

• 1mm medial displacement of the medial wall results in a 0.4 ml increase in orbital volume

• 1mm inferior displacement of the floor results in a 0.8 ml increase in orbital volume

• An increase in orbital volume of approximately 1.25 ml will result in 1mm enophthalmos.

• 10% (2.5ml) increase in volume would be expected to result in clinically significant enophthalmos

• This is roughly equivalent to 3mm inferior displacement of the orbital floor

CLINICAL EXAMINATIONASSESS

• Visual acuity• Eyelids and periorbital regions• Extra-ocular movements• Pupillary light reactivity• Globe projection• Measure enophthalmos with Hertel’s or Naugle’s

exophthalmometer• Vertical dystopia with clear ruler• Paresthesias• Canthal positions• Eye and ZMC symmetry in all three planes

EXOPHTHALMOMETERSHERTEL’S

NAUGLE’S

INVESTIGATIONS

• OM 150 and 300

• CT (axial/coronal) 3-5mm slices

• 3D CT

• MRI + 3D Reconstruction

• Co-localization of CT on MRI

• Sinuscopy

• Computer assisted planning and surgery

TEAR DROP SIGN

CT SCAN

SURGICAL APPROACHES• Subciliary / Subtarsal

• Transconjunctival with / without lateral canthotomy

• Infra orbital

• Lateral nasal approach for medial wall

• Lateral eyebrow

• Coronal

• Endoscopic Intra sinus

CORONAL

SUBCILIARY SUBTARSAL

TRANSCONJUNCTIVAL

VESTIBULAR

INDICATIONS FOR SURGERY

• Enophthalmos of 2mm or more present for 2 weeks• Positive forced duction test (FDT)• Volume expansion on CT scan• Herniation of orbital contents in the maxillary antrum• Combined medial and inferior wall fracture• Isolated medial wall fracture with displacement >3-

5mm• Isolated floor fracture with displacement > 3mm

Early intervention is always beneficial as late intervention gives poor results because of extensive scarring and muscle shortening !!

AIMS OF SURGERY

• Restore anatomy

• Restore orbital volume

• Preserve vision

• Improve eye movements

• Restore esthetics

MANAGEMENT ENOPHTHALMOS WITH ISOLATED ORBITAL FRACTURES

• Expose the fracture site• Free all the entrapped and herniated tissue• Wide subperiosteal exposure • Find a fixed base posterior to the globe• Reconstruct the defect with graft or plate• Graft or plate should fit passively and must be fixed to the

base or rim with plates/screws• Graft must be placed behind the globe axis to push it

forward• Assess with FDT again before closure• Close in layers

MANAGEMENTASSOCIATED ZMC FRACTURES

• Expose the fracture sites• Reduce the displaced ZMC and the fractured rims to

their accurate anatomical positions• Rigidly fix ZMC (3 point fixation)• Free any herniated tissue• Graft/plate any defects• Perform FDT before closure• Close in layers

MANAGEMENT ENOPHTHALMOS ASSOCIATED WITH DIPLOPIA

• Correct enopthalmos as explained • If diplopia is not corrected simultaneously, perform

strabismus surgery after 6 months

STRABISMUS SURGERY

• Repositioning of muscle insertions onto sclera• Weakening of the opposing muscles

MANAGEMENT SECONDARY REPAIR

• Refracture ZMC, restore its exact anatomical position and perform 3 point rigid fixation to restore orbital volume

• Free the globe and perform FDT

• Wedge shaped graft can be placed on the floor with its thick portion placed posteriorly to create a ramping effect on the globe

MANAGEMENT ENOPHTHALMOS ASSOCIATED WITH BLIND EYE

• Good results can be obtained by using a magnifying lens in the spectacles

• Vertical prisms can be used to camouflage vertical dystopia

MATERIALS FOR RECONSTRUCTIONa) AUTOLOGOUS BONE

Iliac crestSplit ribCalvariaAnterior antral wallBuccal or lingual cortices of mandible

b) AUTOLOGOUS CARTILAGEAuricular cartilageSeptal cartilage

c) HOMOGRAFTSLyoduraZenodermIrradiated cartilageBanked cadaveric bone

MATERIALS FOR RECONSTRUCTIONd) ALLOPLASTS:

MMASilicone polymersTeflonNylonGelatin filmPorous polyethylene (Medpor)Polydioxanone platesPolyglactin \ Polylactide plates and meshMetal sheets and meshes (Titanium)

ORBITAL IMPLANTS

HYPOGLOBUS

• Lowering of the eyeball

• Can occur alone but usually associated with enophthalmos

• It is assessed by placing a clear ruler in front of the eyeballs

HYPOGLOBUS It is affected by;

• Bony support

• Ligamentous support

• Volume of the orbit

• Volume of the orbital fat and extra-ocular muscles

MANAGEMENT • Equator of the globe runs from lateral orbital rim to

posterior lacrimal crest

• Can be improved by correcting the position of ZMC

• Correction requires bone about 1cm wide and equal to the length of inferior rim

• Bone should be placed directly below the equator to uplift it

COMPLICATIONS

• Failure to correct properly in the initial setting thus requiring secondary repair

• Iatrogenic damage to the globe• Optic nerve compression• Graft resorption and recurrence of enophthalmos• Dacryocystitis• Infection/extrusion of the graft/plate• Foreign body reaction• Tissue sagging owing to inadequate closure• Scarring, ectropion or scleral show

POINTS TO REMEMBER• Orbital volume expansion of 1cc produces enophthalmos of

0.8mm• Vertical dystopia of 1cm can be accomodated and tolerated by

brain• Defects should always be over corrected several mm• Orbital fractures should always be repaired after ZMC• Usually 20-30% resorption occurs in case of autologous grafts• Fixation of graft decreases resorption• If 2 or more walls are fractured, titanium mesh should be used• If both, bone and muscle surgeries are required, perform

muscle surgery after bony surgery• In enophthalmos, graft should be placed behind the globe and

in hypoglobus should be below the globe

REFERENCES

• Principles of Oral and Maxillofacial Surgery by Peterson• Oral and Maxillofacial Surgery by Peter Ward Booth• Oral and Maxillofacial Trauma by Raymond J Fonseca• Facial Plastic, Reconstructive and Trauma Surgery by Robert W

Dolan• Facial trauma by Seth R Thaller and Scott McDonald• Oral and Maxillofacial Surgery by Fonseca, Marciani and Turvey

THANK YOU“A SURGEON IS KNOWN BY THE SCAR HE LEAVES”

(Unknown)