Orbital fractures

A brief overview of Orbital fractures...

1. Prepared by – Dr. Anchal Agarwal Orbital Fracture

2. CONTENTS Anatomy of Orbit – Bony Orbit, Floor, Medial wall, Lateral Wall, Roof ,Apex of Orbit Classification of fracture Pathophysiology of Fracture Blow In fracture Blow Out Fracture – Pathophysiology & Clinical features. Superior Orbital Fissure Syndrome - Pathophysiology & Clinical features. CLINICAL EVALUATION – Forced Duction Test , Hess Chart Management – Incisions – Subciliary , Transconjuctival Orbital Floor Dissection & Reconstruction. COMPLICATIONS

3. Anatomy of Orbit Orbit – conical cavity Base – Anteriorly Apex – directed at Optic Foramen Orbital Volume – 30cc ; Globe – 7cc By Age 5 years orbital growth is 85% complete , Finalised between 7 years of age Bones – 7 (Maxillary, Zygomatic , Frontal, Ethmoid , Larimal , Palatine, and Sphenoid ) Four Walls – roof, lateral, medial, floor Medial wall & floor – thin ; Lateral wall & Roof – Stronger. Floor weakened – due to – Infraorbtal Canal passing through it

4. Medial wall – Formed by – Lamina Papyracea of Ethmoidal bone & Lacrimal bone Vital Contents – Eyeball (Non Compressible) 6 EXTRAOCULAR MUSCLES – Originate from Common Tendinous fibrous ring Annulus of Zinn – Fibrous ring – Common origin of 4 Rectus Muscle OPTIC NERVE – direct extension of Gray Matter Very sensitie to Compression and once damaged fails to regenerate SUPERIOR ORBITAL FISSURE Transmits – 3 rd , 4 th & 6 th Cranial Nerves Opthalmic Division of 5 th Cranial Nerve Opthalmic Artery & Vein

5. Cranial Nerves and its Supply Occulomotor (C.N.-III)- Supplies – Superior Rectus Medial Rectus Inferior Rectus Inferior Obliqus Abducent Nerve – Lateral Rectus (LR6 ) Trochlear Nerve – Superior Obliqus (SO4)

6. Theoretically, the mechanical load of the orbital floor is approximately 0.0005 N/mm2 (30 g orbital content onto 600 mm2 of orbital floor area), as indicated by several cadaver investigations.

7. CLASSIFICATION ORBITAL WALL FRACTURES – Blow Out Fracture Pure Blow Out Fracture Impure Blow Out Fracture Blow In Fracture ISOLATED ORBITAL WALL FRACTURE : Roof Floor Medial wall Lateral wall

8. ISOLATED FRACTURES OF THE ORBITAL RIM : SUPERIOR RIM INFERIOR RIM MEDIAL RIM LATERAL RIM COMPLEX COMMINUTED FRACTURES : Nasoethmoidal and fronto - naso -orbital fractures

9. Anatomy of Bony Orbit

10. Floor Of Orbit Extends – Rim to approx. 2/3 rd of the depth of the orbit Posteromedial aspect of Orbital floor transitions into Medial Orbital Wall – to form – Posterior Medial Bulge Only three of four orbital wall extend into the Apex – Medial, Superior , Lateral Anterior third – Diameter widens behind Superior Inferior margins ‘Post Entry Concavity’ – Saggital plane – ‘Lazy S’ shape Peterson’s Principles of Oral and Maxillofacial Surgery ; 2 nd Edition ; Page – 463- 464

11. Floor of Orbit Surface Landmarks – Infraorbital Groove – bony sulcus Inferior Orbital Fissure – converts into canal – continues to Infraorbital Foramen Origin Of Inferior Oblique Muscle Posterior Lateral Promontry – Posterior medial bulge ending in a raised Promontory shaped lateral plateau. Delineated – junctional zone of – Maxillary surface of orbital floor & Orbital process of Palatine bone

12. Orbital Fissures/Canals and Their Contents

13. MEDIAL WALL Convex Rectangular shape Runs Parallel to Saggital Plane Medial wall – paper thin Lamina paprycea – (0.2-0.4mm) Reinforced along the Maxillary- Ethmoidal suture --- forming an Internal Orbital Buttress. Peterson’s Principles of Oral and Maxillofacial Surgery ; 2 nd Edition ; Page – 465

14. Surface Landmarks – Lacrimal Fossa – Anterior 1/3 rd of the Medial Wall Frontoethmoidal suture – Roof of the ethmoid sinus at the level of the cribriform plate Ant. & Post. Ethmoidal Foramen – along frontoethmoidal suture in midorbit Distances – Medial orbital Rim – Ant. Ethmoid Foramen – 22-25mm Post. Ethmoid Foramen to Ant Ethmoid Foramen – 12-15mm Post Ethmoid Foramen & Optic Canal – 3-7mm Peterson’s Principles of Oral and Maxillofacial Surgery ; 2 nd Edition ; Page – 465

15. LATERAL WALL Forms – Triangle with an anterior base Forms 45degree angle to its medial wall counterpart SURFACE LANDMARKS – Whitnall’s tubercle – small bony projection – actual insertion is ‘Common lateral retinaculum ’. Lateral horn of lateral aponeurosis Lateral canthal tendon of eyelids Inferior Suspensory (Lockwood’s) Ligaments. Multiple fine check ligaments of Lateral Rectus Muscle. Superior & Inferior Orbital Fissure Zygomaticosphenoid suture – imp. Landmark to verify proper reduction of complex ZMC fracture. Peterson’s Principles of Oral and Maxillofacial Surgery ; 2 nd Edition ; Page – 464- 465

16. Roof Of Orbit Domed contour Comprised of – Orbital plate of the Frontal Bone Extremely thin In Apex – Roof terminates into Lesser Wing of Sphenoid – where Oval shaped Optic foramen forms Optic canal SURFACE LANDMARKS: Trochlear fossa : Zone of attachment of tendon of Superior Oblique muscle Lacrimal Gland Fossa Peterson’s Principles of Oral and Maxillofacial Surgery ; 2 nd Edition ; Page. 464

17. Apex of Orbit Posterior third – made by sphenoid bone Superior Orbital Fissure – separates the Lesser wing of sphenoid & Greater Wing of Sphenoid Optic Canal – within the lesser wing of sphenoid Annulus of Zinn – all Extraocular muscles except Inf. Oblique arises from this tendinous ring

18. Limit of Dissection Inferiorly(Floor) – Upto 28-30mm (safe limit) – optic canal is at around 40mm Laterally – Superior Orbital Fissure Superiorly – Orbital roof dissection is stopped at periorbital surrounding Recurrent Meningeal Artery – passing through bony canal within the Sphenofrontal suture line Medially – Posterior extent – Posterior Ethmoidal vessels , running in the Fronto-Ethmoidal Suture line Anterior to Optic foramen.

19. Distance of Vital Orbital Structures from Bony Landmarks STRUCTURE REFERENCE LANDMARK MEAN DISTANCE (mm) Midpoint of inferior orbital fissure Infraorbital foramen 24 Anterior Ethmoidal Foramen Anterior Lacrimal crest 24 Superior Orbital Fissure Zygomaticofrontal suture 35 Superior orbital Fissure Supraorbital Notch 40 Optic Canal (medial aspect) Anterior Lacrimal Crest 42 Optic Canal (Superior Aspect) Supraorbital notch 45 Peterson’s Principles of Oral and Maxillofacial Surgery ; 2 nd Edition ; Page – 465

20. Pathophysiology of Orbital Fractures

21. In the event of Trauma Thick Rims protect the Eyeball Absorb shock by Fracturing themselves Orbital walls (especially Medial Wall & Floor) fracture in an isolated way Gets displaces Inwards or Outwards Called as ‘ Blow-In ’ or ‘ Blow-Out ’ fractures

22. PURE Blow Out OR Blow In – Orbital Walls fracture in Isolation IMPURE Blow Out or Blow In Fracture – Walls + Rim

23. Blow Out Fracture

24. Blow Out Fracture Term coined by – Smith and Regan – 1957 First described by MacKenzie in Paris in 1844 PATHOPHYSIOLOGY Buckling Theory – 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

25. Pathophysiology of blow out fracture of the orbit 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. Medial Wall & Floor –Thin & Fragile Fracture readily – provide natural compensation As they fracture – Orbital Size increases, Itraorbital pressure compensated. Herniation of periorbital fat

26. Clinical Features Circumorbital Edema - Subconjunctival Bleeding – due to fracture  subperiosteal bleeding  escapes in subconjuctival plane. Enopthalmous  Increase in size of Orbit  Eyeball sinks Periorbital Fat Herniates through fractured walls ‘ Hanging-drop’ Appearance Unilateral Epistaxis – bleeding into antrum Numbness in area of distribution of Infraorbital Nerve Diplopia or Vertical gage – Inferior Rectus or Inferior Obliqus gets entrapped in fracture  inability of eyeball to move in vertical direction.

27. Enopthalmus following Blow-Out Fracture Retracting action of extraocular muscles – Enopthalmus . Diplopia – Entrapment of Inferior Rectus & Inferior Obliqus

28. Superior Orbital Fissure Syndrome Also k/as – ‘ Rochon Duvigneaud Syndrome’ Hirschfeld – first described it. Contents of Superior Orbital Fissure : 3 rd Cranial Nerve ( Occulomotor ) 4 th Cranial Nerve ( Trochlear ) 6 th Cranial Nerve ( Abducent ) 5 th Cranial Nerve (Trigeminal) – Opthalmic Branch Opthalmic Artery Opthalmic Vein

29. Superior Orbital Fissure Syndrome

30. Pathophysiology Raised Intraorbital Pressure (due to Hematoma/Displaced fractured segments) Compression of contents of Sup. Orbital Fissure Paresis of Nerve Neurological deficit in their distribution

31. Occulomotor supplies – SR , MR, IR , IO Abducent – LR Trochlear – SO Due to paresis of these nerves  all these extraocular muscles undergo paralysis  eyeball fails to move  ‘External Opthalmoplegia ’ As affected eye does not move  whereas contralateral normal eyeball moves  focal axis gets disturbed  two images - Diplopia

32. Clinical Manifestations External Opthalmoplegia – Eyeball fails to move Diplopia – Two images of one object Internal Opthalmoplegia – Fixed Dilated pupils (parasympathetic – III cranial nerve – Occulomotor ) Ptosis of Upper Eyelid – upper eyelid drops down like a curtain – parasympathetic supply. Orbital Apex Syndrome – If Optic Nerve Involvement is present.

33. BLOW IN FRACTURE Fragmented bones of the orbital floor are displaced into the orbit. Proptosis – Exopthalmous More commonly seen in fractures of – orbital roof

34. CLINICAL EXAMINATION Initial Opthalmological evaluation – 1. Periorbital Examination 2. visual acuity – SNELLEN CHART 3. ocular motility – FORCED DUCTION TEST 4. Pupillary responses ,- pupillary size, shape& symmetry, light reactivity, 5. Visual fields – HESS CHART 6. Fundoscopic examination TONOMETRY – to assess Intraocular pressure (Normal 10-20mmHg) 7. Hertel Exopthalmometer – measure exopthalmous

35. Forced Duction Test Prior to the performance of a forced duction test, a cotton-tipped applicator is soaked with topical anesthetic drops and held against the limbus for a few minutes. Fine-toothed forceps are then used to grasp the conjunctiva and Tenon’s capsule just posterior to the limbus . The patient is then asked to look in the direction of restriction of movement of the eye .

36. Snellen chart Tonometer

37. HESS CHART

38. IMAGING CT Scan – Orbit - To visualize the fractured segments CT Scan – also helps evaluate the Intraorbital volume. By using a software to compare the normal orbital volume to the affected MRI

39. Management

40. In 1984 Smith and colleagues introduced the concept that Volkmann’s contracture might occur as a result of elevated intraorbital compartmental pressure Although this phenomenon was well known in orthopedic literature , to occur within extremities, it was unproven in orbit Applying this concept to the orbit Smith and colleagues recommended surgical intervention in the elderly , in individuals who are hypotensive , and for small or linear orbital floor fracture with coexsisting diplopia. They felt these pateints were at higher risk of developing Orbit Compartment syndrome.

41. Indications for surgical managment Unresolving soft tissue entrapment with disabling diplopia Enopthalmous greater than 2mm CT scan evidence of a large fracture SURGICAL MANAGEMENT : 1.CLOSED REDUCTION – Transantrally .- Caldwell Luc Procedure Trannasally – Through inferior turbinate – foley’s catheter

42. Incisions Existing lacerations LowerEyelid – 1) Subciliary 2) Subtarsal 3) Infraorbital approaches Transconjuctival Approach – Lower Eyelid

43. SAGITAL SECTION THROUGH ORBIT & GLOBE C- Palpebral Conjuntiva IO- Inferior Oblique muscle IR- Inferior Rectus Muscle OO- Orbicularis Oculi OS – Orbital Septum P - Periosteum / Periorbita TP- Tarsal Plate.

44. Orbicularis Oris Muscle Innervated by Cranial Nerve VII Upper Eyelid – Levator Palpebral Superioris – Cranial Nerve III Orbicularis Oculi - Orbital and Palpebral Portions Palpebral Portion is divided into fibers - Pretarsal Portion - in front of the tarsus. Preseptal Portion - in front of the orbital septum.

45. Subciliary Incision The incision is approximately 2 mm below the eyelashes and can be extended laterally as necessary (top dashed line). It is made throug skin only .

46. Subcutaneous dissection of skin, leaving pretarsal portion of orbicularis muscle attached to tarsus. Dissection 4-6mm inferiorly in this plane is adequate Subcutaneous dissection through the lid margin

47. Use of scissors to dissect through orbicularis oculi muscle over lateral orbital rim to identify periosteum .

48. Incision through the bridge of orbicularis oculi muscle. Sagital plane through orbit showing incision of the bridge of orbicularis oculi muscle.

49. - Incision through periosteum along anterior maxilla, 3 to 4 mm inferior to infraorbital rim. - Note the pretarsal muscle still remaining on the inferior tarsus and the orbital septum, which restricts the orbital fat from entering the field . - Subperiosteal dissection of anterior maxilla and orbital floor. Note that the periosteal elevator entering the orbit is placed almost vertically as dissection proceeds behind the rim. -In the anterior region, the floor of the orbit is at a lower level than the crest of the rim, necessitating dissection inferiorly just behind the crest of the rim.

50. Sagital plane through orbit showing subperiosteal dissection of the anterior maxilla and orbital floor.

51. TRANSCONJUCTIVAL APPROACH Fig.1 - Incision of the conjuctiva below the tarsal plate Fig 2 - Incision through periosteum . To facilitate this maneuver , a traction suture is placed through the cut end of the conjunctiva to retract the tissue and maintain the position of the corneal shield. Small retractors are placed so that the lower lid is retracted to the level of the anterior surface of the infraorbital rim. The intervening tissue along the infraorbital rim is the periosteum . The incision is made through the periosteum just posterior to the infraorbital rim.

52. Sagital plane through the orbit and globe demonstrating level and plane of incision. The conjunctiva and lower lid retractors are incised with scissors .

53. SUBPERIOSTEAL DISSECTION OF THE ORBITAL FLOOR . Note the traction suture placed through the cut end of the conjunctiva, which assists in retracting the conjunctiva and maintains the corneal shield in place .

54. Orbital Floor Dissection Periorbital is elevated from the underlying bone As dissection continues posterolaterally , the inferior orbital fissure are visualized The periorbital dissection along the orbital floor proceeds posteriorly in a twohanded technique using a malleable ribbon retractor with a wide rounded tip and a periosteal elevator. In order to ensure a clean periosteal dissection, the bony contours must be respected

55. Surgical Exposure After periorbital dissection is performed, adequate exposure, ( proper retraction ) and illumination of the fractured area is imperative. Malleable retractors, spoons and special orbital retractors designed for the globe

56. Transition between anterior mid orbit , the orbital floor slopes upwards giving rise to the – posterior medial bulge & Slightly convex bony platform Elevator passed transversely along the inferior orbital fissure Infraorbital neurovascular bundle can be visualized first shining through the thin bony roof of its canal Then it becomes directly visible in the infraorbital groove Depending on the amount and severity of comminution around the course of the infraorbital nerve, a bony decompression might be indicated.

57. EXTENT OF DISSECTION Taking into account the extent of fracture, the periorbital dissection stops at the medial border of the inferior orbital fissure leaving the soft tissue invagination intact Laterally , the dissection is continued to the posterior edge of the floor to the orbital process of the palatine bone . The suture between the maxilla and the palatine bone is indistinguishable in the adult skull. Medially t he periorbital dissection (as shown in the anatomic specimen) extends to the zone over the internal orbital buttress where the orbital floor blends into the medial wall .

58. In many cases a periorbital dissection of the floor with a tunnel medial to the inferior orbital fissure will be sufficient. For an EXTENDED ACCESS to the posterior orbital floor, the contents of the inferior orbital fissure must be addressed and transected to allow for this additional access. The transsection is prepared with a dissection along the inferior portion of the lateral orbital wall in order to create a second tunnel alongside the vertical softtissue partition

59. The intervening soft tissue invagination is transected in a stepwise fashion using bipolar electrocautery and sharp dissection across the fissure above the level of Müller’s vestigial muscle, stripping the periorbita along the lateral edge of the inferior orbital fissure. This illustration demonstrates the stripping of the periorbital layer from the inferior lateral orbital wall immediately adjacent to the inferior orbital fissure with a sharp elevator proceeding posteriorly .

60. Limit of Dissection Inferiorly – Upto 28-30mm. Laterally – Superior Orbital Fissure Superiorly – Orbital roof dissection is stopped at periorbital surrounding Recurrent Meningeal Artery – passing through bony canal within the Sphenofrontal suture line Medially – Posterior extent – Posterior Ethmoidal vessels , running in the Fronto-Ethmoidal Suture line Anterior to Optic foramen.

61. The subperiosteal dissection is continued using a periosteal or freer elevator in a lateromedial direction and lifted up and retracted by and by with the ribbon retractor until the entrance of the apex is reached.

62. Reconstruction Material

63. Pre-formed Orbital Implant ADVANTAGES : Radiopacity Smooth Surface Minimal or no countouring necessary DISADVANTAGE : Cost

64. Bone Graft Disadvantages : Additional Donor site needed Possible contour and dimensional changes due to remodeling Difficult to shape according to patients anatomy

65. Porous Polyethylene Sheet (PPE) Disadvantages : Not Radiopaque (Not visble on Post Operative Radiographs Lack of Rigidity when very thin wafer of PPE is used. When a more thick rigid wafer is used there is a risk of causing dystopia

66. COMPOSITE OF POROUS POLYETHYLENE AND TITANIUM MESH By combining titanium mesh with porous polyethylene – Material becomes radioopaque More rigid than porous PPE. ADVANTAGE : Stability Contouring Adequate in large three wall fractures Radiopacity No Donor Site Needed DISADVANTAGES : Less Drainage from orbit than with titanium mesh

67. RESORBABLE MATERIALS Thermoplastic and Non Thermoplastic Materials ADVANTAGES : Availability Handling/ Contourability (only for thermoplastics) Smooth surface and smooth edges Disadvantages: - No radiopacity - Degradation of material with possible contour loss Sterile infection / inflammatory response - Difficult to shape according to patients anatomy (only for non-thermoplastics) - Less drainage from the orbit than with uncovered titanium mesh.

68. COMPLICATIONS EARLY COMPLICATIONS : 1. Hemorrhagic or orbital hematoma – treated by -lateral cathotomy immediately, lateral canthal Tendonlysis , Lateral canthotomy – indicated when – - Decreased visual acuity Introcular pressure more than 40mmHg Proptosis Opthalmoplegia

69. Retrobulbar hemorrhage Rare, rapidly progressive life threatening emergency that results in accumulation of blood in the retrobulbar space Increased IOP  stretching of the optic nerve & blockage of ocular perfusion Proptosis , marked subconjuctival ecchymosis & edema ,

70. Symptoms seen are – pain , decreasing visual acuity, diplopia Treatment includes iv mannitol – (used to treat raised intracranial pressure) Acteazolamide – carbonic anhydrase inhibitor ; diuresis in PCT of kidney – excretion of NA, K, Cl – lowering BP, IOP Megadose Steroid Therapy – 100mg Dexa as an i.v. bolus with 40mg 6 hourly in severe unresponsive cases ( Anderson et al 1982) 3. Blindness 4. Superior Orbital Fissure syndrome

71. OCULOCARDIAC REFLEX/ TRIGEMINOCARDIAC/ TRIGEMINOVAGAL REFLEX – The oculocardiac reflex pathway begins with the afferent fibres of the long & short ciliary nerves that travel with the opthalmic division of the trigeminal nerve to the gasserion ganglion via the sensory nucleus of the trigeminal nerve. In the floor of the 4 th 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 mucle tissue of the heart.

72. CLINICAL FEATURES – Bradycardia Faintness Further stimulation can lead to cardiac dysrhythmias Atrioventricular blocks Asystole Bradycardia has been attributed to Trigeminal derived vagal reflex

73. LATE COMPLICATIONS Altered vision Diplopia Ectropion – lower eyelid turns outward Epiphora – overflow of tears onto the face – insufficient tear film drainage from eyed in that tears will drain down the face rather than through nasolacrimal system Enopthalmous

74. References ROWE & WILLIAM’S Maxillofacial Injuries FONSECA - Peterson’s Textbook of Oral & Maxillofacial Surgery – R.M. Borle

75. THANK YOU

76. Dissection between orbicularis oculi muscle and orbital septum. The dissection should extend completely along the orbital rim and superiorly to the level of subcutaneous dissection. Sagital plane through orbit showing level and extent of dissection. Note the bridge of orbicularis oculi muscle remaining between the lid and skin/muscle flap.

77. Linear Fracture