Orbital anatomy and orbital frcture/ dental implant courses by Indian dental academy

GITAM DENTAL COLLEGE & HOSPITAL

DEPARTMENT OF

ORAL & MAXILLOFACIAL SURGERY

SEMINAR ON

ORBITAL ANATOMY & ORBITAL FRACTURES Presented By:

Dr. Sambhav K Vora I MDS

CONTENTS

1. Orbital anatomy 2. Orbital trauma a. Aim & objective b. Classification c. Pathophysiology d. Clinical presentation e. Ophthalmic evaluation f. Imaging g. Specialized investigation h. Management i. Postoperative ophthalmic examination j. Complication k. Conclusion l. References

Orbital anatOmy: Orbit is a bony cavity shaped like a pyramid with its apex at optic foramen.

Orbit growth is 85% completed at 5 yrs and growth is finalized between 7yrs to puberty.

Seven bones contribute to the formation of the orbit – Maxillary, Zygomatic, Frontal, Lacrimal, Ethmoidal, Sphenoidal, Palatine.

Importance of orbit: to protect vital structures present within the orbital cavity, because globe is surrounded by fat &medial wall &floor of the orbit are thin ,so forces transmitted to the globe allows fracture of the orbit without significant globe injury &this accounts for the higher incidence of the fracture of the orbit as compared to open globe injuries.

Relation:

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Superiorly – Anterior cranial fossa and frontal lobe.

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Inferiorly – Maxillary sinus.

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Medially – Nasal cavity,Ethmoid sinus.

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Laterally – Temporal fossa.

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Posteriorly – Middle cranial fossa & temporal lobes of brain.

Boundaries : Roof –it is formed by Orbital part of frontal bone and lesser wing of sphenoid (Posteriorly).

Medial wall – •

Extending in front from anterior lacrimal crest,running backwards across lacrimal bone and then to paper thin orbital part of (lamina papyracea) and finally to bony of sphenoid.

•

Between anterior and posterior lacrimal crest is the fossa for lacrimal sac, which leads down into nasolacrimal canal.

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At junction of roof and medial wall, lie anterior and posterior ethmoidal foramina.

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Distance from anterior lacrimal crest to anterior ethmoidal foramen is 24 mm,from anterior ethmoidal foramen to posterior ethmoidal foramen is12 mm,from posterior ethmoidal foramen to optic foramen is 6 mm.so total distance from anterior lacrimal crest to optic foramen is 42mm.

•

Lateral displacement of frontal process of maxilla, to which medial palpebral ligaments are attached, produces a condition called traumatic telecanthus.

TRAUMATIC TELECANTHUS: It is bilateral displacement of medial palpebral ligaments by outward movement of their bony attachments or avulsion.

Intercanthal distance has to be known for checking telecanthus: Waardenburg states (1951)-33mm to 34mm in males 32 mm to 33mm in females.

Freihofer (1980)-

26mm to 38mm in males(avg 31.7) 30.8 In females.

Average interpupillary distance is 55 mm.

Lateral wall – (5cm long) •

This wall separates orbit from temporalis muscle.

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Formed by zygomatic bone and greater wing of sphenoid.

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Posteriorly there is a gap called superior orbital fissure between lateral wall and roof which lies in middle cranial fossa.

•

Inferior orbital fissure – between lateral wall and floor which lies in

pterygopalatine and infra temporal fossa.

Contents of Superior orbital fissure:  lacrimal nerve,  frontal nerve,  trochlear nerve,  superior ophthalmic vein,  Inferior ophthalmic vein.  ophthalmic artery,  nasociliary ,  abducent ,  occulomotor The last 3 contents are found within the muscle cone Any trauma which causes direct compression or compression hematoma on the contents of superior orbital fissure produces a condition called superior orbital fissure syndrome or full blown syndrome.

Features of full blown syndrome: •

Loss of sensation over forehead-because of involvement of supratrochlear &supra orbital nerve.

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Edema of periorbital region-involvement of ophthalmic vein

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Proptosis-because of intraconal &extraconal hemorrhage

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Dilation of pupil-because of blocking of parasympathetic supply via occulomotor nerve

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Ptosis-occulomotor nerve

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Opthalmoplegia-involvement of occulomotor ,trochlear &abducent nerve

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Loss of corneal reflex-involvement of nasociliary branch.

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Loss of direct light reflex-occulomotor nerve

Contents of inferior orbital fissure •

maxillary nerve,

Floor – it is formed by orbital surface of maxilla, laterally by zygomatic bone &posteriorly by orbital process of palatine bone.

Infra orbital foramen lies about 1 cm below the middle of the infra orbital margin.

Shape: triangular with rounded corners, being narrower posteriorly &merging medially with orbital plate of ethmoid.floor slopes upwards &medially at 45degrees.

Floor is very thin, about 0.5cm thick &is further weakened by infra orbital grooves &canals.meadial to this line only most blow out fracture occurs.

ORBITAL RIM: Lateral rim- formed by frontal process of zygomatic bone &zygomatic process of frontal bone.

Approximately 0.75 cm above the rim, lacrimal gland is located. Pilot hole should be commenced 1.5 cm above the frontozygomatic suture &0.5 cm behind the rim, penetration should not be more than 0.75 cm About 1 cm below the suture &3 mm inside the rim .whitnalls tubercle is present; transosseous wiring should be avoided at this area.

Superior rim: more rounded, as it passes medially, where it overlies the outer limit of frontal sinus.

Any injury to this area supra orbital & supratrochlear nerves &vessels will also be affected.

Medial rim: as medial palpebral ligament is attached to this part, displacement of bone in this region causes displacement of canthal &suspensory ligaments.

Inferior rim: just within the rim, a small depression which marks origin of the inferior oblique muscle ,only muscle not arising from back of the orbit.

RONTAL’S relationship of important structure to well define landmarks in the walls: •

Infra orbital foramen to midpoint of inferior orbital fissure-24 mm

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Frontozygomatic suture to superior orbital fissure -35mm

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Supra orbital notch to superior orbital fissure -40 mm

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Supra orbital notch to superior aspect of optic canal-45mm

Subperiosteal dissection should not be extended more than 25mm posterior to inferior &lateral rim and 30 mm from superior rim &anterior lacrimal crest

EYELIDS:

Are movable folds covered externally by thin skin &internally by transparent mucous membrane called palpebral conjunctiva which is reflected onto the eyeball, which continuous with bulbar conjunctiva, which is thin, transparent &attached to anterior surface of eyeballs.

Superior &inferior eyelids are strengthened by superior & inferior tarsi. Between the nose and medial angle of the eye is MEDIAL PALPEBRAL LIGAMENT, which connects tarsi to medial margin of the orbit.orbicularis oris originate & inserts into this. LATERAL PALPEBRAL LIGAMENT arises from tarsi &attaches to the marginal tubercle of whitnall’s on zygomatic bone just below the zygomaticofrontal suture, inside the orbital margin.

Medial canthus is separated by a small triangular space called lacus lacrimalis, in the centre there is a small pink elevation called caruncle.

Antimongoloid slant-separation of lateral palpebral ligament at frontozygomatic suture produces the appearance called Antimongoloid slant where in lateral canthi will be drooping downwards. Lateral horn of levator tendon is also attached to this tubercle, so lowering of this structure along with lowering of lateral attachment of suspensory ligament produces some degree of pseudoptosis.

Mongoloid slant: whenever there is fracture involving frontal process of the maxilla .medial canthal ligament attached to this gets disturbed producing inferior displacement of bone resulting in mongoloid slant .pseudoptosis is not seen here as medial horn of levator is poorly defined.

ORBITAL FASCIA: (periorbita) it forms the periosteum of the bony orbit. Due to its loose connection to bone .it can be easily stripped.posteriorly it is continuous with duramater &with sheath of optic nerve. Anteriorly it is continuous with periosteum lining the bones around the orbital margin. At the upper & lower margins of the orbit .it send off flap like extension into the eyelids called orbital septum. Periosteum is very thin & easily perforated, when carrying out exploration of orbital floor so that periorbital fat can readily escape.

Bulbar fascia: (tenons capsule) surrounds the eyeball &separates it from orbital fat. triangular expansions from medial &lateral recti forms medial &lateral check ligaments, which are attached respectively to lacrimal and zygomatic bones. Sleeve of inferior rectus is thickened on its underside &blends with sleeve of inferior oblique, as well as check ligaments to form SUSPENSORY LIGAMENT (hammock like support for the eye).

ORBITAL SEPTUM: extends from periphery of the orbit to fuse with the attached margins of the tarsal plate. It arises from the thickened periosteum,then passes over the orbital rim to enter the orbit

is pierced by various tendons, nerves &vessels.

Following nasoethmoidal fracture, surgical emphysema may result if patient has subsequently blown the nose as air gets collected in the preseptal space, anterior to tarsal plate.

PERIORBITAL FAT: Frictionless packing materials upon which muscles can rotate the eyeball within the capsule of tenon.two principal compartments within the orbit are •

Central/intraconal-fusion of membrane with extra ocular muscle responsible for eye movements.

•

Peripheral/extraconal-presents between muscles &periorbita.

Both of the above spaces contain fat

LACRIMAL APPARATUS: production &removal of tears. it consists of lacrimal gland,lacrimal canaliculi,lacrimal sac,nasolacrimal duct.

Lacrimal gland-it is a serous gland with large orbital &small palpebral part. orbital part lies in the lateral part of the roof of the orbit supported by aponeurotic tendon of levator palpebrae superioris.closure of the eyelids begins at the lateral side of the upper lid &moves medially so tears spread across the eye. At the medial end, low elevation at lid margin called lacrimal papilla surrounded by lacrimal punctum which opens into lacrimal canaliculus which convey tears to lacrimal sac. And from there to nasolacrimal duct, which is 2 cm long, slopes downwards, backwards &laterally &opens into anterior part of the inferior meatus 2 cm behind the nostril.

MUSCLES OF THE ORBIT: Extra ocular muscle: Voluntary -1.rectus: superior Inferior Medial Lateral 2. Oblique: superior Inferior.

3. Levator palpebrae superioiris Involuntary-superior tarsal muscle Inferior tarsal muscle Origin &insertion: Four recti muscle arises from a common tendinous ring &inserted into the sclera.

Superior oblique arises from body of sphenoid &inserted into the sclera.

Inferior oblique muscle arises from the orbital surface of the maxilla

Levator palpebrae superioiris arises from the orbital surface of the lesser wing of the

sphenoid.

Nerve supply: all the muscles of orbit are supplied by occulomotor nerve except superior oblique &lateral rectus.

Superior oblique is supplied by trochlear nerve.

Lateral rectus is supplied by abducent nerve.

Movements of the eyes: Superior rectus: moves eye in upward direction, medial direction&intortion.

Inferior rectus: moves eyes in downward direction, medial direction & extortion.

Superior oblique: moves eye in downward direction, lateral direction&intortion.

Inferior oblique: moves eyes in upward & lateral direction&extortion.

Medial rectus: moves eyes in medial direction.

Lateral rectus: moves eyes in lateral direction.

Orbital trauma AIM 1. To manage trauma or any injury to the orbital region by accurate diagnosis &appropriate surgical approach.

2. to correct diplopia &enopthalmos.

OBJECTIVE 1. To eliminate cosmetic, functional &ophthalmic complications 2. To establish appropriate treatment modality for the achievement keeping complications in mind.

CLASSIFICATION OF ORBITAL FRACTURES ORBITAL WALL FRACTURES 1. Blow out fractures a. pure blow out fracture b. impure blow out fracture.

2. Blow In fracture.

ISOLATED ORBITAL RIM FRACTURE: a. superior b. inferior

c. lateral d. medial.

ISOLATED ORBITAL WALL FRACTURE: a. roof b. floor c. medial d. lateral.

ORBITAL FRACTURES WITH FOUR ABBREVIATIONS11 a. Four letters defining the localization: F: frontal, N: nasal, M: maxilla, Z: zygomatic bone. b. Two acronyms describing fragment shift: IN: blow in, OUT: blow out. c. Four numbers defining ocular movement impairment: 1. Superior, 2. Internal, 3. Inferior, 4. External extrinsic muscular deficit. d. Two acronyms defining eye position: EX: exopthalmos, ENO: enopthalmos.

PEDIATRIC CLASSIFICATION OF ORBITAL FRACTURES15 Type 1: pure orbital fracture (40.7%) Type 2: craniofacial fracture (35%) Type 3: common fracture pattern (25.9%)

PATHOPHYSIOLOGY Mechanism of fracture is still unclear. Many theories have been put forward to explain the mechanism: BUCKLING THEORY2 This theory states that if a force was to strike any part of the orbital rim ,it will cause walls to undergo a rippling effect &the force striking the rim will transfer to the weaker

portion especially the floor &cause them to distort &eventually fracture.

HYDRAULIC THEORY (Pfeiffer in 1943): He said that it is evident that the force of the blow received by the eyeball was transmitted by it to the walls of the orbit with fracture of the delicate portions. Therefore direct injury to the globe forcing it into the orbit was necessary.

Flaws regarding these theories: 1. Not isolating the striking force to specific areas of face.

2. Using dried fixed cadavers with lowered intra ocular pressure.

3. Some specimens having no orbital content.

CONVERSE &SMITH: due to increase in the hydrostatic pressure induced by direct trauma to the globe.

FUJINO &MAKINO: entrapment of periorbital tissue between fractured orbital segments.

LENDING: bone elasticity facilitates deformations of orbital framework which in turn causes fracture of the orbital floor.

CLINICAL PRESENTATION according to LESTER 9&his associates the following findings were found more frequently

Periorbital ecchymosis (100%) Inability to elevate globe (90%) Vertical diplopia (90%) Infra orbital hypoesthesia (56%) Depression of the globe (30%) Enopthalmos (5.75%) Along with this –

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edema

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Subconjunctival hemorrhage

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Ptosis

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Pseudoptosis

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Intraocular pain

OPTHALMIC EVALUATION 1. Visual acuity-it is tested independently for each eye using a snellen chart at a standard 20 foot distance or a near card (standard type print at 14 inches)if a snellen s chart is not available. if the patient wears corrective lenses ,then should be worn during examination.

2. Ocular motility 3. Visual fields-are tested for each eye ,one at a time by confrontation. this involves directly aligning the patient s& examiners faces 2 feet apart(both maintaining direct front gaze)&asking the patient to detect movement at the extremes of the examiner’s own visual field.

4. Color examination 5. Pupilary responses-Pupilary size, shape &symmetry should be evaluated, as well as light reactivity. An irregular pupil often points towards the site of globe penetration or injury.

6. Fundoscopic examination IMAGING 1) Standard radiographs-foreign bodies can be detected on plain films, but localization is difficult. It is inadequate in evaluating internal orbital fractures &soft tissues.

2) Caldwell’s projection (superior, lateral, medial orbital rim and ethmoidal and frontal sinuses are better viewed) 3) Water’s projection-allows visualization of orbital roof &floor blow fractures.

4) Lateral projections-may be used to study floor &posterolateral orbital wall 5) Basal &oblique projections may be used to evaluate the optic canal.

6) CT scan8 CT allows excellent visualization of orbital soft tissues as well as the ability to simultaneously assess the intra cranial cavity when evaluating orbital trauma. Fractures are best evaluated when the imaging plane is perpendicular to the fracture line.

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Sagittal plane are most important radiological view in diagnosis of orbital floor blow out fracture (view is however impractical and unnecessary).

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Coronal plane CT scan provides successful diagnosis

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Standard approach is 3mm axial and coronal scanning

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Coronal section shows orbital floor and roof fracture

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Sagittal section shows anterior and posterior fracture margins.

Limitations of CT- 1.coronal ct is uncomfortable &often impossible to perform.

2. Sedation is frequently required in pediatric patients.

3 .cost of ct scanning is higher than the cost of standard radiographs.

4. Radiolucent foreign bodies are often missed on ct scan.

7) MRI •

Limited use in orbital trauma.

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Useful for assessing soft tissue involving such as incarceration of extra ocular muscles or orbital fat.

OBLIQUE SAGGITAL VIEW AS AN ADJACENT TO CORONAL CT12 (For the evaluation of orbital floor fracture) Location and the size of the fracture in the anteroposterior dimension and volume displaced from the orbit into the maxillary sinus and the evidence of the inferior rectus muscle entrapment were improved in this technique.

SPECIALIZED INVESTIGATION ULTRASOUND DIAGNOSIS – of the orbital wall fracture with a curved array transducer20. It has not yet reached the diagnostic quality of CT, but is a helpful diagnostic imaging tool in cases with clear clinical symptoms.

Foreign bodies in the anterior orbit may be identified.

CDI (Color Doppler imaging) – recent ultrasound technique gives simultaneous two dimensional imaging of structures and blood flow. Evaluates post traumatic high flow carotid cavernous fistula.

1. Forced duction test: a local analgesic solution is instilled into the conjunctival fornices &tendon of the inferior rectus muscle is grasped by forceps through the conjunctiva &an atte mpt made to rotate the eye upwards. Alternatively a suture may be passed through the tendon for the same purpose but care should be taken to ensure the suture does not come in contact with the cornea.

Use of succinylcho line provides sustained contraction of the extra ocular muscles that interfere with the accurate interpretation of the forced duction test up to 20 mins.

2. Electromyography – it is done by ophthalmologist. It helps in differential diagnosis of combined injuries such as incarceration of inferior rectus muscle in association with weakness of superior rectus.

3. Orbitography – it is a diagnostic technique based upon, injection of the radio opaque contrast medium along the floor of the orbit.

MANAGEMENT Conservative approach

Medical Care 1. Steroids to decrease orbital edema Prednisolone 80 mg/ kg/day on 1 st day, followed by 60 mg next 24 hours, & then followed by 40 mg for next 2 days Hydrocortisone -1 gm /kg /day, with a tapering dose.

2. Antibiotics preoperatively incase of elderly patients and continued for 2 weeks post operatively.

3. I .v fluids in the form of mannitol 0.5 mg or 200 ml of 20 % solution should be given to reduce any hemorrhage or hematoma 4. I .v acetazolamide 500 mg can be given to reduce hemorrhage & also intra ocular pressure to some extent.

5. Avoiding nose blowing for several weeks to avoid orbital emphysema.

Surgical approach Timing of repair5 Immediate repair 1. Non resolving oculocardiac reflex with entrapment.

2. Early enopthalmos measuring more than 3 mm.

3. White eyed floor fracture, commonly seen in children.

Repair within 2 weeks 1. Symptomatic diplopia with a positive forced duction test.

2. Large orbital floor fracture that may cause enopthalmos.

3. Evidence of soft tissue entrapment on CT. 4. Progressive infraorbital hypoesthesia.

Observation 1. Minimal diplopia (not in primary or down gaze) 2. Good ocular motility 3. No significant enopthalmos i.e. not more than 1 -2 mm.

Surgical Care Criterion for surgical intervention 1. To release increased volume of the orbit.

2. To relieve any entrapment of the muscle 3. For proper functioning of the eye.

Absolute Contraindications 1. Critical condition of the patient.

2. Rupture of the globe 3. Single eye functioning

Surgical intervention Steps involved in surgical intervention: i.

Approach to the fractured site

ii.

Selection of graft material

iii.

Placement of graft material

iv.

Stabilization of graft material

v.

Repositioning of periosteum

vi.

Repositioning of the tissues

1. Access to orbital floor is made through various approaches.

SUBCILIARY APPROACH18

Once the skin is incised, the surgeon has three options. The first is to dissect between the skin and the muscle until the orbital rim is reached, at which point another incision through muscle and periosteum is made to the bone. The second option is to incise through muscle at the same level as the skin incision and dissect down just anterior to the orbital septum to the orbital rim. The third option is a combination of these in which subcutaneous dissection toward the rim proceeds for a few millimeters followed by incision through the muscle at a lower level, producing a step-incision, then following the orbital septum to the rim.

The first flap is technically difficult to elevate and accidental "buttonhole" dehiscence can occur. A further problem that may occasionally be seen is a slight darkening of the skin in this area after healing. Presumably, the skin flap becomes avascular and essentially acts as a skin graft. An increase in the incidence of ectropion has also been noted by some investigators with this approach. Entropion and lash problems have occasionally been experienced after this "skin only" flap The second option, in which the dissection is made between muscle and orbital septum, is technically less difficult. Care must be taken, however, because the thin orbital septum can be easily violated, causing periorbital fat to herniate into the wound The third technique, in which a layered dissection is used, avoids the disadvantages of the Others. The main advantage of the "stepped" incision through skin and muscle is that the pretarsal Fibers of the orbicularis occuli can be kept attached to the tarsal plate, presumably assisting in maintaining the position of the eyelid and its contact with the globe postoperatively First approach-

Incisions are made 2mm below the edge of the eyelid and a mid tarsal incision is made between the edge and the orbital rim. First protection of the globe has to be done with the help of temporary tarsorraphy suture or scleral shell. There is a skin crease which is situated about 2 to 3 mm away which provides a convenient line to follow. This incision is made through skin only. The skin is then reflected down, by blunt dissection, until it is free from the pretarsal part of the orbicularis occuli. The muscle

fibers are then spread to expose the periosteum of the lateral border initially. Sub muscular dissection is continued until septum orbitale is seen. Most surgeons try not to incise the septum in that it causes herniation of orbital fat through it. This can be difficult to manage. It also will reduce the risk of vertical lid shortening. From this the infraorbital rim can easily be identified. Therefore periosteal incision and elevation can take place. Elevation of the orbital contents to expose any floor defect can be

made

Advantages i.

Quick and easy to do

ii.

Estimation of giving incision can easily be done in case of edema

iii.

Scar inversion is greatly diminished.

Disadvantages i.

Highest incidence of ectropion.

ii.

Vertical lid shortening.

ALTERNATIVE TECHNIQUE: EXTENDED LOWER EYELID APPROACH The incision for the "extended" subciliary approach is exactly as described for the standard subciliary incision, but the incision must be extended laterally approximately 1 to 1,5 cm in a natural crease . If no natural skin crease extends laterally from the lateral palpebral fissure, the extension can usually be made straight laterally, or slightly inferolaterally.

Supraperiosteal dissection of the entire lateral orbital rim is performed with scissor dissection to a point above the frontozygomatic suture . The orbicularis occuli musculature and superficial portion of the lateral canthal tendon are retracted as the dissection proceeds With retraction, an incision through the periosteum 2 to 3 mm lateral to the lateral orbital rim is made from the highest point obtained with supraperiosteal dissection . The periosteal incision is connected to the one described from the standard approach to the orbital floor and infraorbital rim . Subperiosteal dissection must strip all of the tissue from the orbital floor and lateral orbital wall. This includes stripping the insertions of the deep portion of the lateral canthal tendon, Lockwood's suspensory ligament, and the lateral check ligament, from the orbital (Whitnall's) tubercle of the zygoma. Generous subperiosteal dissection deep into the lateral orbit allows retraction of these tissues to expose the frontozygomatic suture.

TRANSCONJUNCTIVAL METHOD: The transconjuntival incision, also called the inferior fornix incision, is a popular approach for

exposure of the orbital floor and infraorbital rim. Two basic transconjuntival approaches, the preseptal and retroseptal, have been described. These approaches vary in the relationship of the orbital septum to the path of dissection (Fig. 3-1). The retroseptal approach is more direct than the preseptal approach and easier to perform. The periorbital fat may be encountered during the retroseptal approach, but this is of little concern and causes no ill effects. A lateral canthotomy is frequently used with transconjunctival incisions for improved lateral exposure. The approach that will be demonstrated here is the retroseptal transconjunctival approach with a lateral canthotomy

This approach involves no disruption of the outer surface of the eye lid. In this method the lower lid is pulled forward & held by traction suture which is inserted into the margin of the lower eyelid .a small incision is made 3 mm below the tarsal plate on the medial aspect .tissues are then separated on a plane superficial to orbital septum but deep to orbicularis oculi muscle,using blunt dissection &a small guaze swabs until the orbital rim is reached. The periosteum is then divided just above the infra orbital foramen &elevated from the lateral to medial aspect until the rim is reached.

To help increase the laxity of the lid a lateral canthotomy can be performed. This will allow the edge of the tarsus to be seen. Two methods can then be used to achieve access to the floor. Preseptal or retroseptal.

The preseptal incision is where the incision is made at the edge of the tarsus.this will ensure that the space can be created in front of the orbital septum to reach the orbital rim, The retroseptal incision involves incision 2mm below the tarsus,however dissection to get to orbital rim is same.

Advantages i.

Excellent asthetic results and quick to do.

ii.

No skin muscle resection

iii.

Low incidence of ectropion

iv.

Scar can rarely be seen

Disadvantages i.

Limitation of access

ii.

Medial extent is limited

2. Tissues are then separated on a plane superficial to the orbital septum, but deep to orbicualris oculi muscle using blunt dissection and small gauze swabs, until rim is reached. Periosteum is now divided just above the infraorbital foramen and elevated from lateral to medial side.

Retraction is maintained by means of malleable copper strip. This allows elevation of periorbita along the floor and release of entrapped orbital contents.

3. After release of entrapped contents, repair is carried out by means of grafts12.

Auto grafts – are used for larger defects. Different types of auto grafts used are 

Calvarial bone



Inner plate of ileum9



Septal cartilages

Advantages: i.

Avoids risk of infected implants.

Disadvantages i.

Additional operative time

ii.

Donor site morbidity

iii.

Graft absorption

Alloplastic materials21 used are 

Sialastic sheets



Porous poly ethylene

Advantages of silastic sheets Nice capsule forms along the implant, decreases the chance of extrusion rate  It has smooth surface so orbital tissue does not get attached to the implant &therefore less chances of diplopia later on.  Ease of shaping, conforming and placement are comparable.

Titanium – are used for larger defects

Disadvantages

 It has to be cut into proper shape to adapt it to the defect wall, so while adapting that it creates sharp edges which need to be trimmed off or abraded s  It has holes in it, so chances of orbital tissue getting incorporated is more ,& Therefore more chances of postoperative complications.  To overcome this problem titanium sheets covered by thin sheets of porous polyethylene on both sides are recently used.



Smooth nylon foils (suprafoil) orbital implants13 These are recently used materials for reconstruction of orbital floor .



Reconstruction with resorbable mesh plate16

Advantages: i.

Maintenance of orbital contents against herniation forces during initial healing phase

Disadvantages: i.

Anterior displacement of mesh causing ectropion and enopthalmos and requiring reoperation.

4. To secure this graft: - soft stainless steel wire or fine braided stainless steel suture wires are passed through graft.

Titanium mesh also useful to support large bony grafts.

Alternatively microplate or miniplate can also be used.

5. After securing the graft, irrigation of the wound is done. Orbital periosteum and its free margin sutured to the cut edge below the inferior orbital rim with interrupted 3-0 chromic catgut. Next level to be closed is muscular layer, only 2-3 sutures are given. Skin edges are accurately apposed with slight evertion of the margins using 5-0 gauge silk suture or similar size synthetic material.

ENDOSCOPIC ORBITAL FLOOR REPAIR6 Endoscopic repair of the orbital blow out fractures could become predictable and efficient treatment alternative to traditional methods.

The purpose was to provide anatomical description of orbital floor via endoscopic approach.

0 degree and 30 degree rigid endoscope was used by a Caldwell luc approach.

Maxillary osteum , orbital floor and lateral ethmoid air cells were visualized including fracture pattern and force transmission pathways.

And orbitomaxillary sinus bony thickening was identified and described for the first time.

Combination of transconjunctival and endoscopic transnasal approach 1 Advantages

i.

Posterior edge of the fracture and herniated tissue before reduction can be seen.

ii.

Less invasive

iii.

Dual manipulation by two surgeons is also possible in reduction and reconstruction of orbital floor.

70 degrees straight endoscopy is introduced through an enlarged ostium as for functional sinus surgery allowed clear site of the roof of the antrum. Through transconjuctival approach reduction and reconstruction was assisted from antrum.

The large orbital defects were reconstructed with silicon sheets, thin iliac bone grafts or nasal septal cartilage.

Post operative infection was not observed.

Transcaruncular approach for reconstruction of medial orbital fracture19 Medial orbital fracture can cause horizontal diplopia and enopthalmos.

Incision is made in the caruncle and extended into the conjunctiva superior and inferior into the fornices for 10-12mm.The tissue is bluntly dissected in an anteroposterior direction. The periosteum was incised dorsally of the posterior lacrimal crest and after elevation of the periosteum, the fractured orbital wall was visible.

Transplant upto a height of 2cm could be inserted for reconstruction using resorbable poly dioxanone plate.

Cortical bone was used for reconstruction of late enopthalmos Scar formation was absent C- ARM TRANSCONJUNCTIVAL APPROACH3 New approach using a C shaped extended transconjuctival approsch os possible to have one field of vision to see the frontozygomatic suture, the lateral orbital wall, inferior orbital rim, lateral maxillary buttress and zygomatic arch.

Advantages over other approaches i.

Less operation time

ii.

Post surgical scars are lesser.

OPTHALMIC EXMINATION a. Pre operative b. Intra operative

c. Post operative PREOPERATIVE EVALUATION i.

Palpation and observation - Eyelid, canthus, eye movements

ii.

Schirmer’s test-this test is done to check the dryness of the eye.

A standardized strip of sterile filter paper are placed over the margins of the lower eyelid, by measuring the length of wetting of filter paper tear production can be assessed. Values below 5 mm after 5 min period are highly susceptible of keratoconjunctivitis sicca. & values from 0 to 2 mm strongly confirm dry eye state.

iii.

Fundoscopic examination-this is done by ophthalmoscope or fundoscope.it is used in determining health of retina &vitreous humour .it is also indicated for raised intra ocular pressure.

There are 2 types of ophthalmoscopes-direct &indirect.

Direct-it is the instrument of the size of a small flash light with several lenses that can magnify up to 15 times. This is routinely used for examination.

Indirect-it has a light attached to a headband; in addition to small handheld lens. it has a wider view of the inside of the eye.

iv.

Patency of the lacrimal system can be demonstrated by passage of dye from conjunctival cul de sac into the nasal cavity.

v.

CT scans and MRI

INTRAOPERATIVE EVALUATION i.

Enopthalmos

ii.

Telecanthus

iii.

Ptosis

iv.

During dissection of medial orbital wall, optic nerve is at greater risk

POST OPERATIVE CARE i.

Examination of the function of the eye

ii.

Patients with sighted eyes should be checked for visual acuity

iii.

If patient complains of loss of light perception then he should be returned immediately to the operating room (for either removal some of the bone graft or for decompression of optic nerve)

COMPLICATIONS  Early complications  Late complications EARLY COMPLICATIONS – occurs at the time of or immediately after the surgery.

1.Hemorrhagic or orbital hematoma-treated by lateral canthotomy immediately, lateral canthal tendon lysis,iv acetazolamide 500mg ,iv mannitol 0.5 mg

2. Retro bulbar hemorrhage-the following signs are seen..

Proptosis, marked subconjunctival ecchymosis &edema, globe very hard on palpation, dilating pupil, increased intraocular pressure on tonometry, Symptoms seen are-pain, decreasing visual acuity, diplopia.

Treatment includes iv mannitol,(200 ml of 20%solution),iv acetazolamide500mg,&megadose steroids 3-4 mg /kg as initial dose followed by 1-3 mg/kg 6 hourly for the following 24 hours reducing to 1 mg/kg over the next 2 days.

3. Blindness

4. Superior orbital fissure syndrome

6. Oculo cardiac reflex/ trigeminocardiac/ trigeminovagal reflex – The oculo cardiac reflex pathway begins with the afferent fibres of the long & short ciliary nerves that travel with the ophthalmic division of the trigeminal nerve to the gasserion ganglion via the sensory nucleus of the trigeminal nerve. In the floor of the 4th ventricle short internuncial fibres in the reticular formation connect them with the efferent pathway from the motor nucleus of the vagus nerve to the depressor nerve ending in the muscle

tissue of the heart.

Clinical features- bradycardia, faintness, and further stimulation can lead to cardiac dysrhythmias, ectopic beats, atrioventricular blocks & asystole.

Bradycardia has been attributed to trigeminal derived vagal reflex.

6. Caratico cavernous fistula-if the injury of the orbit extends to cause a basal fracture which tears the carotid artery within the cavernous sinus producing an arterio-venous fistula. This characteristically results in a pulsating exophthalmoses worse on bending down &diminished by occlusion of the ipsilateral carotid artery. Bruit will be heard on auscultation over the frontal region.

Treatment includes surgical closure of the fistula or its obliteration by embolisation.

LATE COMPLICATION4

•

Altered vision

•

Diplopia

•

Ectropion and epiphora

•

Enopthalmos

REFERENCES

1. Br.journalof plastic surgery ;jan 57(1)57(1)37 (1)37 -44 2. Buckling theory ,j craniofacial surgery sept 2002 vol 17 3. C arm of cranio facial surgery..2001,nov 4. Canadian j.of plastic surgery,sept/oct 2001vol99 5,183-192 5. Clinical recommendations for repair of isolated orbital floor fracture,M.Burnstine.opthalmology2002 vol109,(7),1207-1210

6. Endoscopic orbital floor repair J. of craniofacial surgery.2008 jan 7. Fonseca vol 3 trauma 8. Journal of laryngology &otology 9. Lester Mc,blow out fractures of orbit ;br.j.plastic surgery,1965(18);171 10. Materials for reconstruction, Michael burnstine,opthalmology2002 11. New classification and imaging of orbital fractures (J Craniofacial Surg Nov 2006, Vol.17, 6, 1042-1044) 12. Oblique Sagittal view;joms 2004 nov 13. Ophthalmic plastic &reconstruction surgery.july/aug 2008 24 (4);266-270 14. Ophthalmology, orbit vol 27 3 may 2008 147-151 15. Pediatric classification of orbital fracture, plastic reconstruction surgery,sept 2008,122 (3),886-897 16. Reconstruction of floor with resorbablemesh plate J. of craniofacial surgery,2007may18(3);598-605 17. Rowe and Williams maxilla facial injuries second edition vol 2 18. subcilairy approach,MJAFI;2004;60 392-394 19. Transcaruncularapproach,ijoms,vol 29 issue 4 ,264;267,may 2002 20. Ultra sound diagnosis;joms 2006 jan 21. Wendy.W.Lee, orbital floor implants :what to choose