The medical records of 12 patients with SOP were retrospectively reviewed. Each of these patients had unilateral SR muscle recession for residual head tilt after IOmuscle weakening due to SOP. The residual torticollis was classified into three groups on the basis of severity mild, moderate, or severe. Both IOmuscle overaction and vertical deviation, features of SOP, were evaluated in all patients. The severity of the preoperative and postoperative torticollis and vertical deviation were compared using a paired t-test and Fisher's exact test.
RESULTS:
The torticollis improved in nine of 12 (75%) patients after SR muscle recession. The difference between the preoperative and postoperative severity of torticollis was statistically significant (p = 0.0008). After surgery, the mean vertical deviation was significantly reduced from 12.4 prism diopters to 1.3 prism diopters (p = 0.0003).
CONCLUSIONS:
Unilateral SR muscle recession is an effective method to correct residual head tilt after IOmuscle weakening in patients with SOP. This surgical procedure is believed to decrease head tilt by reducing the vertical deviation and thereby the compensatory head tilt.