BROWN'S SYNDROME

Signs and Symptoms

Restriction of eye elevation in adduction.

Brown's syndrome, also known as superior oblique tendon sheath syndrome, is characterized by restriction of eye elevation in adduction. While the eyelid fissure may widen when the eye is adducted, the motility disturbance, since it arises from mechanical factors, typically remains constant on versions, ductions and tractional tests.^1,2 Eye elevation does gradually increase as the eye moves from adduction to abduction, where it is observed as virtually normal.¹ Divergence in gaze up may also be seen. The ipsilateral superior oblique does not usually overact or fall into contracture. Variable features include head tilt and tropia of some sort in all fields.^1­6 Patients typically present with a head-back, chin-up posture so as to minimize diplopia. In Brown's original series, a 3:2 predominance existed of women to men, and nearly twice as many cases involved the right eye as opposed to the left. Ten percent of cases were bilateral.¹ Familial occurrence of Brown's syndrome has been reported.¹

Pathophysiology

Brown's syndrome is produced by a restriction of the superior oblique muscle tendon, usually in the region of the trochlear notch.² There is some evidence to support delayed development of the trochlea as a possible cause of Brown's syndrome.³

Brown's simulated sheath syndrome or superior oblique tendon sheath syndrome can be congenital or acquired.¹ The congenital syndrome results from structural anomalies rather than a short tendon sheath. Fibrous adhesions may be present around the trochlear area. Adhesions around the inferior oblique have also been reported.^1­5 Wright reported that the majority of Brown's syndrome patients have a pattern of strabismus that arises from an inelastic superior oblique muscle-tendon complex and not a short tendon alone.⁷ Hadjadj, in a study involving 18 children, reported that limitation of upward gaze in adduction was a constant finding with a positive duction test with compensatory head posture seen in less than half of patients affected.⁸

Acquired cases typically arise secondary to trauma (to the orbit--direct trochlear trauma), orbit or muscle surgery, scleral buckling, frontal sinusitis, sinus surgery, glaucoma drainage device implantation, and inflammation of the superior oblique tendon or sheath (as seen in cases of rheumatoid arthritis and juvenile rheumatoid arthritis). Orbital floor fractures have the ability to trap orbital tissues in such a way as to simulate the syndrome.^1,6 Traumatic Brown's syndrome cases often present with larger tropias than their nontraumatic counterparts.⁷

Management

Brown's syndrome does not necessarily require management. If binocular vision is present and the patient has developed a compensatory head position, treatment may be carried out electively for cosmetic purposes. Treatment is required when visual symptoms, strabismus or incorrect compensatory head position cannot be obtained. Acquired cases that have active inflammation of the superior oblique tendon may benefit from local corticosteroid injections in the region of the trochlea.

The goal of surgery is to restore range of motion. Brown, himself, advocated that the superior oblique tendon be stripped.¹ The results of this procedure are frequently unsatisfactory because of scar tissue proliferation.¹ A newer procedure involving luxation of the entire trochlea, with the superior oblique tendon and orbital structures left intact, appears promising.¹ Tenotomy of the superior oblique tendon also has been advocated.¹ Unfortunately, this frequently produces a superior oblique paresis. Furthermore, if the tendon is not properly tightened, the tenotomy may not improve the restricted movement.¹ Another procedure that has been evaluated for cases of congenital Brown's Syndrome is superior oblique tendon lengthening technique.⁴ Retrospective evaluation of 8 patients with Brown's syndrome (ages 2.5 to 8 years) who underwent superior oblique split tendon elongation as the primary procedure, over a 35-month period, found seven of eight patients had complete resolution of the compensatory head posturing, and achieved some ability to elevate the eye in adduction. The superior oblique split tendon lengthening technique should be considered as a possible procedure of choice for the treatment of Brown's syndrome.⁴

Clinical Pearls

• Prisms may provide some relief from diplopia in acquired forms; however, this is difficult to demonstrate and often variable and incomplete.

Other reports in this section

• Traumatic Optic Neuropathy
• Orbital Inflammatory Pseudotumor
• Brown's Syndrome
• Pseudotumor Cerebri