Marginal myotomy of the minimally overacting inferior oblique muscle in asymmetric bilateral superior oblique palsies.
OBJECTIVE
We report the surgical results of marginal myotomy of a minimally overacting inferior oblique muscle in conjunction with traditional recession or myectomy of the greater overacting inferior oblique muscle in 10 patients with asymmetric bilateral superior oblique palsies and asymmetric inferior oblique overaction.


METHODS
Ten consecutive patients with bilateral superior oblique palsies had a hypertropia in primary position (5-28 PD) and unequal inferior oblique overaction (0 to +2 in the lesser overacting inferior oblique muscle, +2 to +4 in the greater overacting inferior oblique muscle). Reversal of the hypertropia was noted in ipsilateral oblique upgaze. All patients underwent a recession or myectomy of the greater overacting inferior oblique muscle and a marginal myotomy of the lesser overacting inferior oblique muscle.


RESULTS
Seven patients had no vertical deviation in primary position, 2 patients had a residual hypertropia of 2 to 3 PD, and 1 patient had a residual hypertropia of 8 PD. The abnormal head position present preoperatively in 8 patients was eliminated or greatly improved after surgery. Postoperatively all but 1 inferior oblique overaction was graded as 0 to trace. Mean follow-up time was 19 months (range, 1.5-68 months).


CONCLUSIONS
In bilateral superior oblique palsies with asymmetric inferior oblique overaction, a mildly overacting inferior oblique muscle can be corrected by marginal myotomy, combined with a recession or myectomy of the greater overacting inferior oblique muscle. This procedure can reduce or eliminate the hypertropia in primary position while minimizing the possibility of residual inferior oblique overaction.
Harvard Vanguard Medical Associates, Braintree, Mass, USA.
Mei L
ML
Mellott
William E
WE
Scott
Gail L
GL
Ganser
Ronald V
RV
Keech
D000328:Adult; D005133:Eye Movements; D006801:Humans; D008297:Male; D009801:Oculomotor Muscles / Q000601:surgery*; D013285:Strabismus / Q000601:surgery*; D020432:Trochlear Nerve Diseases / Q000601:surgery*; D015348:Vision, Binocular