Brown syndrome is characterized by absence or severe limitation of elevation in adduction, minimal elevation deficit or normal elevation in abduction, divergence in upgaze, and a positive forced duction test on testing elevation in adduction.1 Brown attributed this to a shortened sheath of the superior oblique tendon but later reported a variety of mechanical factors including short tendon, misplaced tendon, and iatrogenic and acquired factors.2 Surgical treatment for Brown syndrome has been advocated when patients have abnormal head posture or manifest hypotropia.1 An exaggerated downshoot in adduction has also been regarded as an indication for surgery.3
A wide variety of surgical procedures for treatment of Brown syndrome have been described over the past 2 decades including: stripping of the superior oblique tendon sheath;4 superior oblique tenotomy;5 superior oblique tenectomy;3,6 simultaneous superior oblique tenotomy and inferior oblique muscle recession;7 and use of a superior oblique tendon silicone expander.8
As would be expected with this large number of different procedures, variable surgical results have been reported,2"7 without consensus. The purpose of this retrospective study is to report the evolution of techniques and the results of surgical treatment for Brown syndrome at two institutions and to identify which procedure, in our experience, was most efficacious. In addition, we will address a previous report of sensory function decline as a potential complication of surgery for Brown syndrome9 and the recommendation to combine simultaneous inferior oblique weakening with superior oblique tenotomy as a primary procedure for Brown syndrome.7
MATERIALS AND METHODS
Charts of all patients who had undergone surgical treatment for Brown syndrome at Texas Children's Hospital, Houston, Tex, and Riley Hospital for Children, Indianapolis, lnd, between 1965 and 1989 were reviewed. All patients had limited elevation in adduction and little if any limitation of elevation in abduction. In addition, all patients had restricted passive elevation in adduction with no restriction of passive elevation in abduction on forced duction testing. None had undergone previous surgery for Brown syndrome. The state of muscle balance and results of sensory testing were recorded before the initial, and after the final surgical procedure. Sensory status in the primary position was recorded as no fusion, fusion with ≥120 seconds of arc stereopsis (subnormal binocular vision), or fusion with s=60 seconds of arc stereopsis (normal binocular vision).10 Muscle balance was evaluated by the following criteria: 1) elevation and depression of the involved eye in adduction; 2) deviation in prism diopters at 6 m and 1/3-m fixation distance in primary position with refractive error corrected; and 3) presence or absence of anomalous head posture. Underaction of a muscle was recorded as: -4 = no excursion from midline, -3 = excursion limited to 1/3 normal, -2 = 2/3 normal excursion, and - 1 = noticeable lag of excursion in adduction compared to the normal side. Overaction was estimated after comparison with the normal side and recorded as: + 1 = mild, + 2 = moderate, + 3 = severe, and + 4 = gross overaction.
Surgical Results in Brown Syndrome Types of Procedures
Thirty-eight patients underwent surgery for Brown syndrome. Twenty-seven were females, 11 were male. The right eye was involved in 25 cases and the left eye in 11; 1 case was bilateral. The mean age at the time of the first surgery was 10 years (range = 2 to 50 years). Excluding the four patients who were 20 years and older, the average age was 7 years old.
The most frequently performed operations to correct the limitation of elevation in adduction were superior oblique tenectomy (25), 7/8 tenotomy of the superior oblique tendon (6), superior oblique tendon sheath stripping (4), and repeat tenectomy (4). For correction of a secondary iatrogenic superior oblique palsy, ipsilateral inferior oblique myectomy (8) and recession of the contralateral inferior rectus (4) were most commonly employed (Table). Patients underwent an average of 1.9 procedures.
The efficacy of each initial procedure for Brown Syndrome was based on the percent of cases that required a repeat procedure for an abnormal head posture, manifest hypotropia, or an exaggerated downshoot while the affected eye was adducted. Seven of 21 cases (33%), in which the first surgical procedure was a superior oblique tenectomy, needed further surgery. When 7/8 tenotomy and tendon sheath stripping were the initial procedures, all cases needed further surgery. Superior oblique tenectomy was less efficacious as an initial procedure when there was a concurrent overaction of the ipsilateral superior oblique. Four of the seven cases which were not successful when superior oblique tenectomy was the initial procedure had either a + 2 or +3 superior oblique overaction in adduction of the affected eye prior to surgery. None of the 14 patients who were cured of Brown syndrome by the initial superior oblique tenectomy had greater than a + 1 overaction of the affected eye in adduction prior to surgery.
A measurable vertical deviation in primary position was present in 29 of 38 (78%) patients preoperatively and in 16 of 38 (41%) patients upon final examination. The mean vertical deviation before surgery was 13? and 4? after the final procedure. Twenty-nine of 38 (77%) cases had -4 elevation in adduction initially and only 2 of 38 (5%) had this degree of restriction after their last surgical procedure.
After surgical treatment, an overall improvement in the patients' sensory status was noted (Fig 1). Sixteen of 34 (47%) patients had no fusion when first examined as opposed to 28 of 34 (82%) with either subnormal binocular vision or normal binocular vision on final examination. No patient had a deterioration of sensory status following a surgical procedure.
An abnormal head posture (either a chin elevation or face turn) was present in 24 of 38 (63%) before surgery (Fig 2) as compared to 7 of 38 (18%) after the operation. In no patient was the anomalous head posture worse as a result of surgery. Of the seven patients with a persistent anomalous head posture after surgery, two showed improvement, but not elimination of the problem as a result of surgery.
Fifteen of 38 (39%) cases developed iatrogenic superior oblique palsy that required surgical correction for an abnormal head posture, a large vertical deviation, or diplopia. The mean onset of the superior oblique palsy was 8.3 months after surgical correction of Brown syndrome (range = 3 to 24 months). Eleven of 38 (29%) patients followed for 1 year or longer did not develop a superior oblique palsy. An additional 11 of 38 (29%) patients were either followed for less than 1 year or required further surgery for Brown syndrome. Since 14 of 15 patients developed an iatrogenic superior oblique palsy within 12 months of surgery for Brown syndrome, the 1-year period was chosen as the time during which a palsy was most likely to become manifest. One patient had simultaneous superior oblique tenectomy with contralateral inferior rectus recession.
FIGURE 1: Surgical results in Brown syndrome sensory status (n = 34). No binocular cooperation = no fusion; subnormal binocular vision = fusion with ≤120 seconds of arc stereopsis; normal binocular vision = fusion with ≥60 seconds of arc stereopsis.
FIGURE 2: Surgical results in Brown syndrome anomalous head posture (AHP) (n = 38).
Since Brown's description of the superior oblique tendon sheath syndrome in 1950, n surgical management of the condition has undergone many modifications and changes. Surgical management at our two institutions has been diverse, as evidenced by the Table.
Although not effective in all cases, our data suggested that superior oblique tenectomy was the surgical procedure most likely to accomplish the goals of surgery; that is, elimination of anomalous head posture, decrease or elimination of manifest hypotropia in primary position, reduction of restricted elevation in adduction, and reduction of downshoot in adduction. Seven-eighths tenotomy at the insertion of the superior oblique tendon, performed in an attempt to decrease the occurrence of superior oblique palsy, was not effective, as all cases in our series needed further surgery for Brown syndrome. However, we have seen this procedure produce excellent results in cases not included in this series. The other procedures done by us were either ineffective or not performed frequently enough for efficacy to be determined.
Overaction of the ipsilateral superior oblique has been reported in about one-fifth of patients with Brown syndrome.12 The authors of that article were unable to correlate the overaction with an extremely tight superior oblique tendon. Although the numbers were small, we found an inverse correlation between superior oblique overaction and the success of superior oblique tenectomy. One can only theorize that the overacting ipsilateral superior oblique was associated with tissue that surrounded the superior oblique tendon which was not included in the superior oblique tenectomy. In future cases, careful preoperative evaluation, along with meticulous dissection and exploration of the superior oblique tendon complex at the time of surgery, may aid in the establishment of a correlation between overaction of the ipsilateral superior oblique and extra-tendinous tissue.
Contrary to a previous report,9 we did not find a deterioration of sensory function in any of our patients as a result of surgery. Actually, the majority showed improvement of their sensory status. We could also not confirm that an associated horizontal deviation was detrimental to a successful surgical outcome, as had been reported previously.3 Of our five patients with a preoperative horizontal deviation, two patients did not change their sensory status and three actually improved after surgery. However, a greater number of cases with concurrent Brown syndrome and horizontal deviation is necessary to allow for a definitive conclusion.
It was evident from our data that surgery was effective in the elimination of anomalous head posture. Only seven patients had anomalous head posture after surgery and of these seven, two had improvement of the head position.
Based on the data presented here, we do not advise simultaneous superior oblique tenotomy and weakening of the ipsilateral inferior oblique muscle as an initial procedure. This approach has been recommended in anticipation of an iatrogenic superior oblique paralysis following a tenectomy of that muscle.7 Of our cases successfully operated on for Brown syndrome and followed for at least 1 year, 11 of 26 (42%) did not develop superior oblique palsy to a degree that required surgery. If superior oblique palsy occurs after performing only the superior oblique tenectomy as the primary procedure, the surgeon is then able to choose either the inferior oblique weakening procedure or contralateral inferior rectus recession as a second procedure based on each patient's findings or complaints after the initial procedure.6 Contralateral inferior rectus recession was the procedure of choice in 4 of 15 cases that required a surgical procedure for iatrogenic superior oblique palsy. In each instance, it was chosen because the measurable vertical deviation or the patient's complaint of diplopia was greatest in downgaze.
Patients and their families should be advised that more than one operation may be necessary to achieve the goals of surgery for Brown syndrome. They may further be told that there is some chance that sensory function will be improved and a good chance that anomalous head posture will be relieved.
1. von Noorden GK Binocular Vision and Ocular Motility: Theory and Management of Strabismus. 4th ed. St Louis, Mo: CV Mosby; 1990:404-408.
2. Brown HW. True and simulated superior oblique tendon sheath syndromes. Doc Ophthalmol. 1973;34:123-136.
3. Eustie H, (VReilly C, Crawford J. Management of superior oblique palsy after surgery for true Brown's syndrome. J Pediatr Ophthalmol Strabismus. 1987;24:10-17.
4. Scott AB, Knapp P. Surgical treatment of the superior oblique tendon syndrome. ArcA Ophthalmol. 1972;88:282-286.
5. Crawford JS. Surgical treatment of true Brown's syndrome. Am J Ophthalmol. 1976;81:289-295.
6. von Noorden GK, Olivier P. Superior oblique tenectomy in Brown's syndrome. Ophthalmology 1982;89:303-308.
7. Parks MM, Eustis HS. Simultaneous superior oblique tenotomy and inferior oblique recession in Brown's syndrome. Ophthalmology. 1987;94:1043-1048.
8. Wright K Superior oblique silicone expander for Brown syndrome and superior oblique overaction. J Pediatr Ophthalmol Strabismus. 1991;28:101-107.
9. Wilson M, Eustis HS, Parks M. Brown's syndrome. Surv Ophthalmol. 1989;34:153-172.
10. von Noorden GK. Infantile esotropia: a continuing riddle. American Orthoptic Journal. 1984;34:52-62.
11. Brown H. Congenital structural anomalies. In Allen JH, ed. Strabismus Ophthalmic Symposium. St Louis, Mo: CV Mosby; 1950:205-236.
12. Sato SE, Ellis FD, PinchoffBS, Helveston EM, Rummel JH. Superior oblique overaction in patients with true Brown's syndrome. J Pediatr Ophthalmol Strabismus. 1987;24:282-286.
Surgical Results in Brown Syndrome Types of Procedures