Journal of Neuro-Ophthalmology, September 1986, Volume 6, Issue 3

Medial orbital wall blow-out fracture producing an acquired retraction syndrome.

Trauma in an 8-year-old Black-Vietnamese boy caused a medial wall blow-out fracture, which presented as an acquired retraction syndrome. Computed tomography demonstrated both the fracture and entrapment of the medial rectus and surrounding tissues. Surgical relief of the entrapment resulted in improvement of ocular motility, but retraction persisted. This is the sixth young black male reported with a medial wall blow-out fracture, which suggests that this group may have an orbital structure vulnerable to this relatively uncommon fracture.

.j. 19Rf> Rdwn Press, Nt'w York Medial Orbital Wall Blow-Out Fracture Producing an Acquired Retraction Syndrome John W. Gittinger, Jr., M.D., James P. Hughes, M,D" and Eugenio L Suran, M.D. Trauma in an S-n',lr-llld BI,Kk-\'i~'tnal1leseboy caused a medial wall bk)\\'-llut iracture, which presented ilS iln acquired retr,Ktion syndrome. Computed tomography demonstrated both the iracture and entrapment of the medial rectus and surrounding tissues. Surgical reliei of the entrapment resullt'd in improvement oi ocular mo­tilitv, but retraction persisted. This is the sixth young black male reported with a medial wall blow-out irac­ture, which suggests that this group may have an orbital structure vulnerable to this relatively uncommon irac­lure. From the Department of Sur~ery, Divisions oj Ophlh"l­mology a.W.G.) and Ololaryn~olllgy (j.r.H.) "nJ the Dl'P.lrI· ment of Radiology (E.L.S.), University 01 M"Ss,Khllselh Ml'J­ical School, Worcester, Massachusl'lt;. Address correspondence and reprinl rl'qlll'sis 10: John W. Gittinger, Jr., M.D., Division of Ophthalmology, Univl'rsitv "I Massachusetts Medical Center, Worcestl'r, MA lllbllS, U.S.A. /53 Blunt trauma to the orbit commonly produces an internal or blow-out fracture of the maxillary bone in the orbital floor, often with entrapment of the inferior rectus and surrounding tissues and consequent limitation of upward gaze (1). Medial wall blow-out fractures, which involve the eth­moid bone, are less frequently recognized. When the medial rectus and surrounding tissues are en­trapped in the ethmoid fracture, this may result in a type of acquired Duane's retraction syndrome (2-15). In the patient reported here, computed tomog­raphy allowed imaging of an isolated medial wall fracture and the entrapped tissues. Surgery was performed to relieve the resulting mechanical ophthalmoplegia. CASE REPORT An 8-year-old Black-Vietnamese boy was lying on a couch watching television when he was kicked in the face by his 13-year-old brother. His mother took him to an emergency room, where he was examined and sent home. The next day he was hospitalized for observation because of leth­argy. For the first time, limitation of eye move­ments was noted. Computed tomography of his head and orbits was interpreted as normal, and he was referred to the University of Massachusetts Medical Center for neuro-ophthalmic consulta­tion. When examined as an outpatient 7 days after his injury, his visual acuity was 20/20 in each eye. There was injection over the insertion of the left medial rectus. Ductions of the right eye were full. The patient could not adduct his left eye past the midline, and abduction was limited to 50% of normal. The globe retracted on abduction. Forced ductions llsing a suction cup device were positive /54 ,. W. GITTINGER ET AL. horizontally and negative vertically, although lim­ited patient cooperation may have affected the findings. Review of the initial computed tomog­raphy revealed clouding in the right ethmoid sinus, suggesting the presence of a fracture. A me­dial wall blow-out fracture with entrapment was diagnosed, and the patient was asked to return in 1 week for re-examination and possible surgery. He did not keep this appointment, but did re­turn 18 days later. The previously noted injection had resolved, but the motility findings persisted (Fig. 1). The patient was admitted to the hospital, and computed tomography clearly demonstrat­ed an ethmoidal fracture with tissue entrapment (Fig. 2). Twenty-seven days after his injury he under­went an exploration of the medial orbit through a skin incision. The area of entrapment was visual­ized, and the surrounding bone removed with a rongeur. Intraoperatively, forced ductions im­proved, but there was some persistent mechanical limitation despite a large exposure and removal of bone. No orbital implant was placed. Postoperatively the patient's ocular motility im­proved, but 2 months after the surgery there was still some limitation of both adduction and abduc­tion, with persistent retraction on abduction (Fig. 3). Exophthalmometry readings using a Hertel­Krahn instrument were 15 for the right eye and 16 for the left eye, with a base of 90. DISCUSSION The mechanism of orbital blow-out fractures is thought to be compression of the orbital soft tissues with increased intraorbital pressure being released by fracture of the orbit at its weakest points. This has been reproduced experimentally in cadavers (16-18). Fractures of the orbital floor associated with fractures of the orbital rim are not considered blow-out fractures, since these former are thought to result from direct trauma to the bony structures. Isolated internal orbital floor frac­tures, however, have been produced in dried skulls subjected to trauma of the infraorbital rim, demonstrating that the orbital contents do not necessarily have to be present in the experimental situation (19). Despite the clinical preponderance of orbital floor fractures, the thinnest parts of the orbital walls are medial and not inferior (20). This dis­parity may be an effect of the bony partitions in ethmoidal air cells that buttress the medial wall and increase its bursting strength. Also, the inci­dence of medial wall fractures is relatively high in autopsy studies (18), and many medial wall frac­tures may go undetected both because they do not produce entrapment as often as orbital floor frac­tures and because the medial wall has been diffi­cult to demonstrate radiologically (7). In 1966 Miller and Glaser reported entrapment (al - t-lli. 1. (8' t-'reoperatlve photographs shOWing position of eyes in straight ahead (center), right and left gaze. Note complete failure of adduction of the left eye on ri ht gaze. There IS limitation of abduction of left eye on left gaze, but retraction of the ?eft eye-which was apparent cllnlcany-is not. wen demonstrated. (b) Posto erative photographs. Sman kelOid at the site of inCISion. Note improvement in add pl' f left eye. Abduction of left eye remains limited, with persistence of retraction~c Ion 0 I Clin N"uro-0l""hal"'ol, Vol. 6, No.3. 1986 MEDIAL BLOW-OUT FRACTURE FIG. 2. A single 1.5-mm computed tomographic axial section with windows set to demonstrate bone (a) and soft tissue (b). (a) Focal bone defect in the medial wall of the left orbit (bracket). (b) Note smaller size of the intraorbital portion of the left medial rectus muscle and its entrapment (arrow) in two ethmoidal cells. 155 (b) TABLE 1. Medial orbital wall blow-out fractures in young black males (26), and in patients with infiltrative orbital dis­ease (27). Most instances of acquired retraction syndrome are mechanical in origin. The patient described here had a Vietnamese mother and a Black American father. A dispropor­tionately large number of cases of medial wall blow-out fractures seem to occur in young black males (Table 1). While this may be a discovery ar­tifact or be due to this group's increased risk for trauma, an anatomic basis should be considered. Bony development may proceed differently in dif­ferent ethnic populations, and a racial variation in the shape of the orbit or in the partitioning of eth­moidal air cells could underlie the racial predomi­nance of this type of fracture. The radiological detection of medial wall frac­tures has been improved by the advent of com­puted tomography, which has the unique ability to visualize both the bony and soft tissues simulta­neously (28,29). Computed tomography has al­most completely replaced previous techniques of the medial rectus with retraction on abduction in a 16-year-old Black boy with fractures of both the medial wall and tloor of the orbit (2). Subse­quent case reports have documented medial wall fractures with entrapment, both with and without retraction (3-15). In all but one case (12), the re­traction had been present on abduction rather than on adduction, as in the typical Duane's re­traction syndrome. This diversity gave rise to an unfortunate proliferation of names for these findings: inverse, reverse, mirror image, and pseudo-Duane retraction syndrome. In the past decade, Huber's clinical classification of congenital Duane's retraction syndrome into Type I (limitation of abduction with retraction on adduction), Type II (defective adduction with re­traction on abduction), and Type III (defective ab­duction and adduction with retraction on adduc­tion) has been confirmed and correlated with electromyography (21). Other congenital misin­nervation syndromes, such as synergistic diver­gence (22), are also probably related to the retrac­tion syndromes. The motility pattern usually observed with me­dial wall entrapment and exemplified by the case reported here most closely resembles Duane's re­traction syndrome Type II, but a more general and apt description would be acquired retraction syn­drome. Acquired retraction syndrome has been recognized after surgery and trauma (23), in pa­tients with rheumatoid arthritis (24) and Frie­dreich's ataxia (25), following sixth nerve palsy Case (reference) Miller and Glaser (2) Maisel. Acomb. and Cantrell (11) Duane. Schatz, and Caputo (13) Duane, Schatz, and Caputo (13) Mirsky and Saunders (14) Present case Age (years) 16 17 12 12 11 8 I Clill Ncurtl·up/liltallll<ll. Vol. 6. No.3. 1986 156 f. W. GITTINGER ET AL. such as linear and hypocycloidal tomography and positive contrast orbitography. The surgiGll treatment of blow-out fractures of the orbital floor is controversial (I). Most reported cases of medi,ll willi blow-out fractures with en­trapment havl' eventually come to surgery. Sur­gel1l1s using a conjunctival approach have found the t'xposure difficult (3,9). The approach taken here was similar to that used in an external eth­moidectomy and allowed excellent exposure of the site of the fracture (30). A small keloid formed in the incision. We elected not to place an orbital im­plant, and despite removal of a large portion of the medial orbital wall, there is no enophthalmos. Orbital implants have both immediate and long­term risks (31) and may not be required when the bony defect is medial. The persistence of the retraction despite freeing of the orbital tissues suggests scarring and con­traction of the tissues around the medial rectus. In one previously reported case, this was a progres­sive process and led to significant motility distur­bances (12). We do not know whether earlier sur­gery would have prevented this complication. REFERENCES 1. Converse JM, Smith B. On the treatment of blowout frac­tures of the orbit. Plast Renmstr Surg 1978;62:100-4. 2. Miller GR, Glaser JS. The retraction syndrome and trauma. Arch Ophthalmol 1966;76:662-3. 3. Edwards WC, Ridley RW. Blowout fracture of medial or­bital wall. Ami OphthalmoI1968;65:248-9. 4. Fischbein FI, Lesko WS. Blowout fracture of the medial or­bital wall. Arch OphthalmoI1969;81:162-3. 5. Trokel SL, Potter GD. Radiographic diagnosis of fracture of the medial wall of the orbit. 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