In the name of Allah, The Most In the name of Allah, The Most CompassionateCompassionate, , The Most MercifulThe Most Merciful

Applied anatomy of the orbit. Applied anatomy of the orbit. The recipe for safe dissectionThe recipe for safe dissection

Muhammad Azhar SheikhMuhammad Azhar SheikhProf: Oral & Maxillofacial SurgeonProf: Oral & Maxillofacial Surgeon

Islamic Int’l Dental College & Allied HospitalsIslamic Int’l Dental College & Allied Hospitals

Orbital fracturesOrbital fractures

Orbital fractures are common

Proper repair is key to restoring normal facial appearance and function

Concerns due to critical structures – eye Concerns due to critical structures – eye ball and contents of SOF, IOF and Optic ball and contents of SOF, IOF and Optic NerveNerve

Bony OrbitBony Orbit

Orbital Fracture & EyeOrbital Fracture & Eye

Documentation of the condition of the eye before and after surgery is critical.

Young patients with small floor fractures, particularly when experiencing severe pain or nausea, must be suspected of having an entrapped inferior rectus muscle.

Mean Values of important structuresMean Values of important structuresRontal Rontal et al.et al.

Infra-orbital foramen to midpoint of IOF Infra-orbital foramen to midpoint of IOF - 24mm- 24mm

Ant lacrimal crest to ant ethmoidal foramen Ant lacrimal crest to ant ethmoidal foramen - 24mm- 24mm

Ant lacrimal crest to Medial aspect of optic canal Ant lacrimal crest to Medial aspect of optic canal - 42mm- 42mm

FZ suture to superior Orbital fissure FZ suture to superior Orbital fissure - 35mm- 35mm

Supraorbital notch to SOFSupraorbital notch to SOF - 40mm- 40mm

Supraorbital notch to superior aspt of orbital canal Supraorbital notch to superior aspt of orbital canal - 45mm- 45mm

DissectionDissection

No bone removal behind Post ethmoidal No bone removal behind Post ethmoidal foramen – this is 30 mm from anterior foramen – this is 30 mm from anterior lacrimal crest.lacrimal crest.

Perisoteum elevation – line extending from Perisoteum elevation – line extending from FZS to FES medially upto 30mm from FZS to FES medially upto 30mm from supraorbital rim without risking any supraorbital rim without risking any structure passing through superior orbital structure passing through superior orbital fissure fissure

Summary Summary (Randal et al.)(Randal et al.)

Superiorly & Medially – 30mm from superior Superiorly & Medially – 30mm from superior orbital rim and anterior lacrimal crestorbital rim and anterior lacrimal crest

Inferiorly & laterally – 25mm from outer rimInferiorly & laterally – 25mm from outer rim

Care – medial canthal ligament, lacrimal Care – medial canthal ligament, lacrimal apparatus, pulley of superior oblique muscle, apparatus, pulley of superior oblique muscle, supraorbital NV bundles, Structures attached supraorbital NV bundles, Structures attached to whitnall’s tubercle and origin of IO muscle.to whitnall’s tubercle and origin of IO muscle.

Age & Gender VariationAge & Gender Variation

The orbital floor angle was greater in males than in females, and in children than in adults. That is steeper in males and children

The location of the lowest point of the orbital floor moves postero-inferiorly with increasing age.

NAGASAO et al. Journal of Cranio-Maxillofacial Surgery (2007) 35, 112–119

Deep Orbit Deep Orbit Evans and Webb. BJOMS 2007Evans and Webb. BJOMS 2007

Reliable landmarks are available

that are based on the relations of

anatomical structures within the

orbit rather than absolute

distances.

Evans and Webb. BJOMS 2007Evans and Webb. BJOMS 2007

The anatomical landmarks of the deep orbit are both hard and soft tissue structures: – the infraorbital nerve;

– the inferior orbital fissure;

– the greater wing of the sphenoid; and

– the orbital plate of the palatine bone.

Surgical LandmarksSurgical LandmarksEvans and Webb. BJOMS 2007Evans and Webb. BJOMS 2007

IO nerve run parallel IO nerve run parallel to medial wallto medial wall

It does not go to Optic It does not go to Optic nerve - safenerve - safe

Follow the nerve until Follow the nerve until inferior orbital fissure. inferior orbital fissure.

Orbital plate of palatine boneOrbital plate of palatine bone

The orbital plate of the palatine bone provides a constant and reliable landmark in the medial orbital floor.

Reconstruction of the floor of the orbit does not need to extend beyond this.

PearlsPearls

Muscle entrapment does not occur in large fractures, but muscle herniation does.

Floor implants should be placed far enough posterior to the orbital rim that they are not palpable.

Approximately 1 cm of floor fracture will allow the eye to move posteriorly about 1 mm

SummarySummarySo-called safe distances, and the subperiosteal plane of dissection within the orbit, do have a role, but are best considered as adjuncts to orbital dissection rather than absolutes.

Used in conjunction with the anatomical landmarks of the deep orbit, safe and reproducible dissection within the orbit is possible in every case of non-ballistic injuries to the orbit, no matter the extent of orbital disruption.

Retrobulbar Hemorrhage Retrobulbar Hemorrhage Signs and SymptonsSigns and Symptons

PainPain

Decreasing visual acuityDecreasing visual acuity

Diplopia ( if vision preserved)Diplopia ( if vision preserved)

Proptosis (often acute onset)Proptosis (often acute onset)

Retrobulbar HemorrhageRetrobulbar HemorrhageTreatment - MedicalTreatment - Medical

IV mannitol (200ml of a 20% sol)IV mannitol (200ml of a 20% sol)

IV acetazolamide (Diamox) 500mgIV acetazolamide (Diamox) 500mg

IV papaverine 40mgIV papaverine 40mg

IV hydrocortisone 100mgIV hydrocortisone 100mg

If no improvement within 20 minutes, surgical If no improvement within 20 minutes, surgical

decompression is necessarydecompression is necessary