Operationsergebnisse bei kongenitalem Brown-Syndrom

Superior oblique split lengthening procedure for brown syndrome, outcomes and complications

INTRODUCTION

To evaluate the outcomes of the superior oblique split tendon lengthening (SOSL) procedure for Brown syndrome (BS).

METHODS

At a single institution, all patients who underwent SOSL surgery for BS from 2013 to 2019 were reviewed retrospectively. We looked at the surgical outcomes and complications in a total of 20 eyes of 18 patients. The superior oblique (SO) muscle was isolated and then extended. The tendon was then split centrally into equal halves. Two 6-0 polyglactin sutures were then placed on each end of the split tendon 6-10 mm apart. To complete the Z-cut, the split tendon was cut distal to the preplaced sutures. The sutures were then tied to produce the split Z-tendon lengthening.

RESULTS

Eleven (55%) out of 20 eyes were female patients. The mean age was 6.6 years (range 2-17 years). The mean follow-up was 26.8 months (range 5-72 months). The mean degree of preoperative limitation of elevation on adduction was -3.6±0.58 preoperatively and -0.75±1.25 postoperatively (p=0.0001). Preoperatively, the mean degree of vertical deviation at near was 3.5±7.62 and at distance was 3.10±7.84 prism diopters (PD), respectively. Postoperatively, the mean vertical deviation was 2.77±4.75 and 2.10±4.08 PD at near and distance, respectively. Postoperative complications included haematoma in one patient (5%), overcorrection in two patients (10%) and one patient required reoperation (5%).

CONCLUSION

SOSL is a safe procedure that surgeons can consider in managing patients with BS.

[Brown's atavistic superior oblique syndrome: etiology of different types of motility disorders in congenital Brown's syndrome]

CLINICAL FEATURES

The congenital Brown syndrome is characterized by a mechanical limitation of elevation in adduction, with an orthophoria in down gaze. Brown postulated a shortened superior oblique tendon sheath as the cause of the limitation but this was disproved by Parks et al. in 1975 and the origin of Brown syndrome remains unclear. In recent years, a congenital dysinnervation has been discussed; however, this does not explain the full spectrum of abnormalities and especially contradicts the unlimited depression in adduction seen in Brown syndrome.

ORIGIN

Surgical exploration in Brown true typical cases reveals a fibrotic strand, typically located at the posterior margin of the superior oblique tendon. This strand originates from the trochlear area and has a common insertion with the superior oblique tendon posterior to the equator into the globe. It may represent an atavistic superior oblique muscle as described by Fink in various animals. They do not have a trochlea but a superior oblique muscle originating in the anterior superior nasal orbit.

ATYPICAL BROWN SYNDROME

A fibrotic strand was also surgically revealed in two cases of atypical Brown syndrome. In the first case an elevation deficit-as in Brown true atypical cases-also present in abduction could be explained by an unusual insertion of the fibrotic strand anterior to the equator. The second case showed a fibrotic strand which was completely separated from the superior oblique tendon and inserted far posterior to the equator nasal to the superior rectus muscle. This finding had not been previously described and explained the total elevation restriction which was suddenly in > 30° adduction and the Y‑pattern exotropia which increased in adduction and decreased in abduction.

TREATMENT AND FOLLOW-UP

A 10 mm excision of the fibrotic strand from the insertion gives the best results from all procedures. The residual limitation of active elevation in adduction improved with gaze exercises mostly after more than 1 year.

CONCLUSION

The fibrotic strand, an atavistic superior oblique muscle, not only explains the typical Brown syndrome but also-by its variable insertion-different patterns of elevation deficits seen in atypical Brown syndrome. A 10 mm excision of the strand gives good functional results of abnormal head position (immediate in most cases) and even elevation in adduction (after 1 year in most cases).

Recurrent Brown's Syndrome after Superior Oblique Tendon Recession Treated by Silicone Spacer

INTRODUCTION

Undercorrections have been reported after a number of surgical procedures for Brown's syndrome. The reason for late undercorrections is not clear but may be related to the heterogeneous etiology of Brown's syndrome.

PURPOSE

We report a patient with late undercorrection after superior oblique tendon recession for Brown's syndrome that was partially relieved by a silicone spacer placed nasally.

RESULTS

We noted on surgical exploration that the superior oblique tendon had attached to the sclera under the nasal border of the superior rectus. Further weakening of the tendon was achieved by a No. 240 band expander that resulted in improvement of adduction in elevation.

CONCLUSION

Undercorrections following surgery for Brown's syndrome can be relieved by further weakening the superior oblique muscle. However, as late undercorrections have been reported, the optimal timing of surgery is not certain.

Absence of the fourth cranial nerve in congenital Brown syndrome

PURPOSE

To elucidate the aetiology of congenital Brown syndrome.

METHODS

Four consecutive patients diagnosed with unilateral congenital Brown syndrome had a comprehensive standardized ocular motility examination. Any compensatory head posture was measured. Brain magnetic resonance imaging (MRI) with regard for the IV cranial nerve (CN) was performed in all patients. Orbital MRI was performed in 2/4 patients, with images acquired in eight directions of gaze and superior oblique (SO) muscle areas compared.

RESULTS

CN IV could not be identified bilaterally in two patients, but was absent only on the side of the Brown syndrome in the two other patients. On the normal side, orbital MRI revealed a smaller SO muscle area in upgaze than in downgaze, demonstrating normal actions of this muscle. On the side of the Brown syndrome, the SO area remained the same in upgaze and in downgaze and approximately symmetric to the area of SO in downgaze on the normal side.

CONCLUSIONS

These cases add further anatomical support to the theory of paradoxical innervation in congenital Brown syndrome. CN IV was absent in two patients on the side of the Brown syndrome, but without muscle hypoplasia. SO muscle size did not vary in up- and downgaze, which we interpreted as a sign of constant innervation through branches of CN III.

Surgical outcomes in correction of Brown syndrome

PURPOSE

To evaluate the outcomes of surgery for Brown syndrome.

METHODS

We reviewed the charts of 15 patients who underwent surgery for Brown syndrome. The limitation of elevation in adduction (LEA) ranged from -2 to -4 degrees. A superior oblique muscle (SO) tenotomy was performed in 4 patients, a silicone expander was inserted in the SO of 9 patients, and a SO recession was performed in 2 patients. The results of surgery were analyzed with a follow-up period of more than 6 months, 42.3 +/- 48.42 months on average.

RESULTS

Nine female patients and 6 male patients with unilateral Brown syndrome were selected for this study. The left eye was the affected eye in 9 patients. The degree of preoperative LEA was -2 to -4 in 4 patients in whom SO tenotomy was performed, -3 to -4 in 9 patients treated with the silicone expander, and -2 to -4 in 2 patients treated with SO recession. The LEA was released after surgery in all patients without postoperative adhesion. However, unilateral overaction of the inferior oblique muscle due to excessive weakening of the SO occurred in 1 patient with tenotomy (25%) and in 1 patient with insertion of a silicone expander (11%).

CONCLUSIONS

LEA was released after tenotomy, insertion of a silicone expander and recession of the SO in 13 of 15 patients with Brown syndrome. SO palsy due to overcorrection and under-correction with postoperative adhesion should be avoided.