Blow out fractures

Blow out fractures

1. Blow Out Fracture vidya

2. Definition Orbital floor fractures are common, and result from blunt orbital trauma in which force is delivered to the thin bones of the orbital floor, typically along the infraorbital canal. The risk of enophthalmos is greatest when both the floor and the medial wall are fractured

3. Expanded orbit syndrome Multiple fractures in and around the orbit may lead roomy orbit with extensive prolapse of orbital tissues. This expansion can be seen in orbital fracture along with mid facial fracture as in tripod or Le Fort type III. Clinically patient has gross enophthalmos, inferior displacement of globe (hypoglobus), deep superior sulcus , eyelid asymmetry and diplopia.

4. pathophysiology Blow out fracture occurs when a blunt object greater in diameter than the orbital rim such as fist, tennis or cricket ball strikes the orbital cavity . The mechanisms proposed for blow out fracture are- Hydraulic theory Buckling theory

5. Hydraulic theory or Retropulsion theory or Direct injury theory: Sudden compression and backward displacement of globe raises the intra orbital pressure leading to fracture of orbital floor. Buckling theory or transmission theory or Indirect injury theory : External force to inferior orbital rim is transmitted along the orbital walls causing a ripple effect leading to fracture at the weakest point in the posterior medial region of the floor.

6. Types a) Pure blowout fracture: Fracture of the orbital floor with intact orbital rim b) Impure blowout fracture: Associated fracture of the orbital rim

7. Orbital blowout fracture in children The bones of a child’s orbit are more elastic than adults. Thus injury in children causes more anteroposterior buckling creating a fracture with overlapping segments. This leads to ‘trapdoor-type’ fracture where prolapsed orbital tissue gets caught in the fracture site leading to severe motility restriction and diplopia in absence of marked congestion or ecchymosis. The condition is also called the ‘white-eyed’ blow-out fracture.

8. Benign external periocular appearance with a remarkable paucity of eyelid signs but with significant extraocular muscle restriction (usually vertical) on examination ( WEBOF). Younger children often do not complain of binocular diplopia, and may simply close one eye. severe oculocardiac reflex a vague history and may therefore be misdiagnosed as having an intracranial injury (e.g., concussion). , CT may show a trapdoor fracture with rectus muscle incarceration or a “missing” inferior rectus. The narrow configuration of the typical WEBOF is often missed on CT imaging, particularly when fine cuts through the orbits are not obtained. Careful examination of coronal views is critical in such cases

9. Clinical features History. General condition of patient Other non ocular injury should be checked. Eyelid signs . Ecchymosis and edema of the eyelids may be present, but other external signs of injury can be absent (white-eyed blowout ).

10. Periorbital haematoma : also proptosis of variable degree seen initially due to orbital edema and haemorrhage Emphysema : Subcutaneous emphysema with crepitus seen in fractures communicating with air filled sinuses. Paraesthesia over ipsilateral lower lid, cheek and upper lip due to injury to infraorbital nerve. Diplopia: Due to restriction of ocular motility. With the entrapment of inferior orbital tissue and inferior rectus muscle, vertical diplopia is more prominent in upgaze .

11. In patients with orbital floor fractures visual loss can result from globe trauma, injury to the optic nerve, or increased orbital pressure causing a compartment syndrome An orbital hemorrhage should be suspected if loss of vision is associated with proptosis and increased lOP. Injuries to the globe and ocular adnexa may also be present.

12. 0.8–1 ml increase of bony orbital volume corresponds to 1 mm of enophthalmos on the Hertel exopthalmometer. Clinically significant enophthalmos (≥2 mm) occurs with increase in the bony orbital volume of 1.5–2 ml.

13. Enophthalmos: Caused by displacement of the eye globe due to an enlargement of the bony orbit. Also displacement of orbital contents into maxillary sinus and traction over globe caused by entrapped tissue leads to posterior and inferior displacement of globe. Pseudoptosis occurs due to loss of support.

14. Evaluation visual acuity at presentation has medico-legal importance in ocular trauma cases. If required eyelids can be gently separated to allow patient to read the chart. Palpate orbital rim to look for deformity and crepitus Slit lamp evaluation of cornea and anterior segment should be performed. RAPD points towards optic nerve injury. Fundus evaluation should be done to note for Berlin’s oedema

15. Ocular motility Hertel exopthalmometer : To document enophthalmos. With passage of time and absorption of orbital fat over period can lead to increase in enophthalmos. Force Duction Test (FDT ): FDT is useful in determining whether dysmotility is restrictive or paralytic. In blow out fracture with inferior rectus entrapment FDT is ‘positive’ indicating mechanical cause. Force Generation Test (FGT ): In testing force generation, the muscle insertion is grasped and the patient is asked to look into the muscle’s field of action. A paretic muscle will feel weak when compared with the fellow eye. Diplopia charting : With red green glass, diplopia charting with streak light shows diplopia worsening in upgaze Hess screen or Lee screen test can be done .

16. Imaging Plain X-rays:. Water’s view for detecting an orbital floor fracture . X ray shows bony discontinuity in orbital floor with herniation of soft tissue in maxillary antrum seen as ‘ hanging drop’ sign CT gives detailed visualization of bony and soft tissue injury where entrapment of muscle can be appreciated. Coronal sections are particularly useful . MRI Can be utilized when there is need for greater soft tissue evaluation . MRI is insufficient in assessing the bony structures and therefore needs to be combined with CT.

17. complications cerebral and ocular damage, severe epistaxis due to avulsion of the anterior ethmoidal artery orbital hematoma, Csf rhinorrhea, Damage to the lacrimal drainage system, lateral displacement of the medial canthus, and Associated fractures of the medial orbital waIl and fl oor.

18. Management . Restriction in ocular movement and / or diplopia is caused not only by entrapment of muscle but soft tissue edema, hemorrhage and motor nerve palsy can also be the cause. A better evaluation can be made if time is allowed for clearing of initial edema and hemorrhage. It is generally accepted that a 2 week window of observation can be allowed in absence of urgent surgical indications

19. Observation : • Minimal diplopia (not in primary or downgaze), • Good ocular motility • No significant enophthalmos or hypo- ophthalmos

20. Medical treatment Consider broad-spectrum oral antibiotics (e.g., cephalexin 250 to 500 mg p.o . q.i.d .; or erythromycin 250 to 500 mg p.o . q.i.d ; or doxycycline 100 mg po b.i.d .) for 7 days. Antibiotics may be considered if the patient has a history of chronic sinusitis, diabetes, or is otherwise immunocompromised . Prophylactic antibiotics should not be considered mandatory in patients with orbital fractures. Patient advised not to blow nose as it can worsen orbital emphysema.

21. Nasal decongestants (e.g., oxymetazoline nasal spray b.i.d .) for 3 days. Use is limited to 3 days to minimize the chance of rebound nasal congestion. Apply q1–2h ice packs for 20 minutes each hour to the eyelids for the first 24 to 48 hours and 30-degree incline when at rest. Consider oral corticosteroids (e.g., Medrol dose pack) if extensive swelling limits examination of ocular motility and globe position. Neurosurgical consultation is recommended for all fractures involving the orbital roof, frontal sinus, or cribriform plate, and for all fractures associated with intracranial hemorrhage. Otolaryngology or oral maxillofacial surgery consultation may be useful for frontal sinus, midfacial , and mandibular fractures

22. Follow up At 1 and 2 weeks after trauma to be evaluated for persistent diplopia and/or enophthalmos after the acute orbital edema has resolved. If sinusitis symptoms develop or were present prior to the injury, the patient should be seen within a few days of the injury. fundus examination to assure there is no peripheral retinal damage. Depending on the level of associated ocular injury, patients should also be monitored for the development of associated ocular injuries (e.g., orbital cellulitis , angle-recession glaucoma, and retinal detachment ). Gonioscopy of the AC angle and dilated retinal examination with scleral depression is performed 3 to 4 weeks after trauma if a hyphema or microhyphema was present. Warning symptoms of retinal detachment and orbital cellulitis are explained to the patient

23. Surgical technique . It is generally accepted that unresolved diplopia with soft tissue entrapment, significant enophthalmos (2 mm or more), marked hypo- ophthalmus , fracture more than 50% of the floor, or trapdoor type fracture will require surgical intervention. Surgical principle in blow out fracture is to assess orbital floor, release soft tissue and muscle entrapment and strengthen the floor with use of implants.

24. Immediate repair If there is clinical evidence of muscle entrapment and nonresolving bradycardia, heart block, nausea, vomiting, or syncope. These may be present despite “negative” CT findings, WEBOF). Patients with WEBOF require urgent orbital exploration to release any incarcerated muscle in the hope of decreasing the chance of permanent restrictive strabismus from muscle ischemia and fibrosis, as well as to alleviate the systemic symptoms from the oculocardiac reflex.

25. Repair in 1-2 weeks Persistent, symptomatic diplopia in primary or downgaze that has not improved over 1 week. CT may show muscle distortion or herniation around fractures. Forced ductions may be useful in identifying bony restriction. Complex trauma involving the orbital rim, or displacement of the lateral wall and/or the zygomatic arch. Complex fractures of the midface or skull base . Nasoethmoidal complex fractures. Superior or superomedial orbital rim fractures involving the frontal sinuses

26. Large orbital floor fractures (>50%) or large combined medial wall and orbital floor fractures that are likely to cause cosmetically unacceptable enophthalmos over time . Enophthalmos and/or hypoglobus at initial presentation is indicative of a large fracture . It is also reasonable to wait several months to see if enophthalmos develops before offering repair. There is no clear evidence that early repair is more effective in preventing or reversing globe malposition compared to delayed repair. However, many surgeons prefer early repair simply because dissection planes and abnormal (fractured) bony anatomy is more easily discernable before post-traumatic fibrosis sets in

27. Delayed Repair Old fractures that have resulted in enophthalmos or hypoglobus can be repaired at any later date.

28. Subciliary approach Transconjunctival approach Transantral approach:. Endoscopic approach: With advances in endoscopic surgery, transmaxillary and transnasal endoscopy has been described which eliminate the need for eyelid incisions and gives improved visualization of fractures.

29. Implants Surgeon should size the implant so as to cover the defect adequately and to prevent displacement or extrusion later Membranous bone Cartilage Titanium mesh Porous polyethylene ( Medpore )sheets Silicon sheet Silastic sheet (Teflon)

30. Complications of surgery • Intra operative bleeding • Residual or new onset diplopia • Extra ocular muscle dysfunction • Post operative neuralgia • Residual enophthalmos • Implant extrusion • Possible loss of vision

31. Treatment of persistent visually handicapping diplopia Few patients will have persistent diplopia even after adequate surgical repair of floor fracture. Diplopia in primary gaze and in down gaze (functional gaze) are more troublesome. Such cases will require muscle surgery. To correct diplopia in down gaze ‘Reverse Knapp procedure’ performed placing medial and lateral recti behind inferior rectus muscle. Fresnel prisms can be employed in selective cases

32. Late treatment of cosmetically unacceptable enophthalmos Resurgery with adequate size orbital implant if downward sinking of eye along with enophthalmos is unacceptable to patient. Correction of pseudoptosis done with mullerectomy which will increase palpebral height.

33. Role of anticoagulants The role of anticoagulation in postoperative or post-trauma patients is debatable. Anecdotal reports have described orbital hemorrhage in patients with orbital and midfacial fractures who were anticoagulated for prophylaxis against deep vein thrombosis (DVT). On the other hand, multiple large studies have also demonstrated an increased risk of DVT and pulmonary embolism (PE) in postoperative patients who are obtunded or cannot ambulate . At the very least, all in-patients with orbital fractures awaiting surgery and all postoperative orbital fracture patients should be placed on intermittent pneumatic compression (IPC) therapy and encouraged to ambulate . In patients at high risk for DVT, including those who are obtunded from concomitant intracranial injury, a detailed discussion with the primary team regarding anticoagulation should be documented, and the risks for and against such therapy should be discussed in detail with the patient and family.

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