Medial Orbital Wall Fracture With Rectus Entrapment Terence M. Davidson, MD; R. Merrel Olesen, MD; Alan M. Nahum, MD

Two cases of medial orbital fracture with medial rectus muscle entrapment are reported, one a bona fide blowout fracture. Review of the literature reveals six

previous

cases.

Clinically, patients complain of diplopia with lateral gaze and forced duction tests confirm medial rectus entrapment. Radiographic confirmation is best obtained with hypocycloidal tomography. Surgical therapy is indicated for diplopia or enophthalmus.

Blowout ondary

fracture of the orbit sec¬ to direct trauma to the is eye frequently seen and is well de¬ scribed in the literature. Although medial wall fracture is not uncom¬ mon1-' entrapment of orbital tissue in a medial wall fracture is rare. Six cases have been reported4 s"!1 and two additional cases are reported here.

Report of Cases Case l.-A 33-year-old man drove a pick¬ up truck off a country road into a telephone pole. He was brought to University Hospi¬ tal 12 hours after injury. Injuries were limited to the face. Bilateral orbital rim fractures were palpable, and subcutaneous emphysema was present over the left side of the face. The nose was freely movable and his maxillae were independently mo¬ bile. The face was elongated. Sensation of the maxillary branches of both fifth cranial

Accepted

publication April 26, 1974. Department of Otolaryngology, University Hospital, University of California at San Diego. Reprint requests to University Hospital of San Diego County, 225 W Dickinson, San Diego, CA 92103 (Dr. Davidson). for

From the

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nerves was decreased to touch and pin¬ prick. Mastication was limited by pain. Af¬ ter several days the periorbital edema de¬ creased sufficiently to permit adequate ophthalmologic examination. Visual acuity in both eyes was 20/20; exophthalmometry, right eye 21, bridge of nose

99, and left eye 18; extraocular

move¬

ment, left eye, full range of motion and

right

eye adduction 10 to 15° and abduc¬ tion 0° with normal elevation and depres¬ sion; there was forced duction in the right eye with normal adduction but abduction was impossible, resulting only in enophthalmus. X-ray studies included a complete facial bone series with stereo Water's view and hypocycloidal tomography of facial bones. These showed a pyramidal facial fracture (Le Fort II) with bilateral infraorbital and lamina papyraceae fractures (Fig 1). The pyramidal fracture was treated with arch bars and wire suspension from the zygomatic arches. On the fourth hospi¬ tal day, the right eye was explored through inferomedial and superomedial orbitotomies. Multiple fractures of the medial orbi¬ tal wall were found. No definite entrap¬ ment was visualized, but after elevating the orbit as far posteriorly as was felt safe, the forced abduction improved. Immediately postoperatively the patient had exotropia of the right eye, 15 to 20° with good abduction and paralysis of ad¬ duction. Over the ensuing month, the eye returned to its normal position, and adduc¬ tion returned to 80% of normal. Two months postoperatively, the eye move¬ ments are normal except for mild diplopia with extreme left lateral gaze. Case 2.-A 19-year-old healthy man was struck over the right eye. The patient came for treatment after several days with bi¬ lateral "black eyes." Examination revealed normal vision with both pupils equal and

Fig 1.—Hypocycloidal tomograph (pa¬

tient 1) showing a pyramidal fracture (Le Fort II) with bilateral infraorbital and lamina papyracea fractures.

light. On right lateral gaze he developed diplopia with restriction of right eye abduction and upward gaze. The eye was thought to be enophthalmic and de¬ pressed. Forced duction was unable to ab¬ duct or elevate the eye. The right orbit was explored through an infraorbital incision carried medially to the palpebrai ligament. The orbital floor periosteum was elevated and the entire central posterior orbital reactive to

floor was found involved with a blowout fracture. The orbital contents were herniated into the maxillary sinus. The con¬ tents were elevated, and an absorbable gelatin sponge (Gelfilm) implant placed over the defect. Forced ductions revealed persistent failure of abduction. The medial wall was explored and a fracture extend¬ ing into the ethmoid air cells identified. The medial rectus muscle was trapped. This was freed and forced duction tests be¬ came nearly normal with mild restriction of extreme lateral gaze. A 0.2-mm silicone rubber (Silastic) sheeting was fashioned to cover both defects. Two weeks postopera¬ tively the patient was well with no diplopia and no restriction of upward or lateral

wall fracture without muscle involve¬ ment is not uncommon if sought with tomography.2·3 Six cases4·5·"-9 of me¬ dial rectus entrapment have been re¬ ported and two additional cases are reported here. All cases have several points in common. A history of blunt trauma to the eye is present. Nasal bleeding and subcutaneous emphy¬ sema may exist. Examination reveals restriction of lateral gaze usually with diplopia. Entrapment must be differentiated from sixth nerve injury and other rare abnormalities resem¬ bling these symptoms.10 Forced duc¬ tion must be performed and will show restriction of abduction. Miller and Glaser' noted retraction of the globe and narrowing of the palpebrai fis¬ sure with forced lateral duction. Xray films are necessary to demon¬ strate the site of fracture. Routine facial films may show the fracture, but frequently will not. The ethmoid cells may be cloudy, and entrapped tissue may even be suspected.2 T The optimal x-ray examination is hypo-

cycloidal tomography.3·711·12 Fig 2.—The bony orbit both outlined In black.

showing

Comment

Medial orbital wall blowout frac¬ entrapment is far less frequent than fracture of the orbital floor with inferior muscle entrapment. With increasing aware¬ ture with medial rectus

cases are

As in the treatment of inferior blowout fractures the indications for

surgical repair are diplopia, enophthalmus, or other evidence of entrap¬

ment. The mere presence of a medial orbital fracture is not in itself an in¬ dication for surgery. Two approaches may be employed to explore the me¬ dial orbital wall. If the inferior por¬ tion of the orbit is explored, as in our patient 2, then the incision may be extended and the dissection carried medially. Mustarde et al" point out that care for the medial canthal liga¬ ment is imperative and suggest cut¬ ting and resuturing it. If no inferior orbital injury is suspected and partic¬ ularly if there is suspected injury to the medial canthal or lacrimal appa¬ ratus, a superior approach is indicated over the anterior lacrymal crest.14 This has the advantage of reaching more superiorly, being more cosmetic and allowing better access to repair the medial canthus. It has the dis¬ advantage that the orbital floor can¬ not be inspected simultaneously. If

the medial orbital wall and the orbital floor. These

gaze.

ness,

Treatment

being correctly diag¬

nosed. Medical orbital wall fracture with entrapment may occur as a single entity or may coexist with an orbital floor fracture. Medial orbital

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are

need be, both approaches may be used as in our first case. If entrapped muscle is found it should be freed and normal motion confirmed by forced duction. If a se¬ vere defect is found it may be covered with a thin piece of silicone rubber sheeting or autogenous material, eg, anterior wall of maxilla. Pre- and postoperative antibiotic prophylaxis is used, especially when silastic im¬ plants are used. Comment The bones of the inferior and me¬ dial orbit are shown in Fig 2. The or-

bital floor is the roof of the maxillary sinus. The medial orbital wall is com¬ prised of the lacrimai bone anteriorly and lamina papyracea of the ethmoid bone posteriorly. Medial wall frac¬ tures usually involve the lamina pap¬ yracea. In examining a skull it is evi¬ dent that the lamina papyracea is markedly thinner than the inferior orbital wall. Yet orbital floor frac¬ tures are far more common than me¬ dial wall fractures. The explanation is simple. Bone is brittle and cracks in response to de¬ formation. The orbital floor bone is supported on each side but in the

middle is without any support. Simple that even a small pres¬ sure will cause substantial deforma¬ tion of the orbital floor. The lami¬ na papyracea is supported by many small struts, the bony septa of the ethmoid sinus. It is not easily de¬ formed and is not easily fractured. The only remaining question is why does the medial wall ever fracture? Probably as long as the ethmoid bony septa are intact the medial orbital wall will not fracture in response to a true "blowout" type injury. When it is involved more than the "blowout" mechanism is suspect.

physics shows

References 1. Converse

JM, Smith B: Naso-orbital fracOphthalmol Otolaryngol

tures. Trans Am Acad

67:622, 1963.

2. Jones IE: X-ray findings. Trans Ophthalmol Otolaryngol 67:635, 1963.

Am Acad

3. Dodick JM, et al: Concomitant medial wall fracture and blow out fracture of the orbit. Arch Ophthalmol 85:273, 1971. 4. Miller GR, Glaser JS: The retraction syndrome and trauma. Arch Ophthalmol 76:662, 1966. 5. Edwards WC, Ridley RW: Blow-out fracture of medial orbital wall. Am J Ophthalmol 65:248, 1968.

6. Rumelt MB, Ernest JT: Isolated blowout fractures of the medial orbital wall with medial rectus muscle entrapment. Am J Ophthalmol 73:451, 1972. 7. Tokel SL, Potter GD: Radiographic diagnosis of fracture of the medial wall of the orbit. Am J Ophthalmol 67:772, 1969. 8. Fischbein FI, Leski WS: Blow out fracture of the medial wall of the orbit. Am J Ophthalmol

81:162,

1969.

Magnus WW, et al: A conjunctival approach to repair of fracture of medial wall of orbit: Report of a case. J Oral Surg 29:664, 1971. 10. Hoyt WF, Nachtigaller H: Anomalies of 9.

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ocular motor nerves. Am J Ophthalmol 60:443, 1965. 11. Dodick JM, Galin MA, Berrett A: Radiographic evaluation of orbital blow out fracture. Can J Ophthalmol 4:370, 1969. 12. Haverling M: Diagnosis of blowout fracture of the orbit by tomography. Acta Radiol [Diagn] (Stock) 12:347, 1972. 13. Mustarde JC, Jones LT, Callahan A: Ophthalmic Plastic Surgery, Up To Date. Birming-

ham, Ala, Aesculapius Publishing Co, 1970, p 190. 14. Mustarde JC: Repair and Reconstruction in the Orbital Region. Baltimore, Williams & Wilkins Co, 1971, p 290.

Medial orbital wall fracture with rectus entrapment.

Two cases of medial orbital fracture with medial rectus muscle entrapment are reported, one a bona fide blowout fracture. Review of the literature rev...
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