Surgical interventions for vertical strabismus in superior oblique palsy

Full citation: Chang MY, Coleman AL, Tseng VL, Demer JL. Surgical interventions for vertical strabismus in superior oblique palsy. Cochrane Database of Systematic Reviews 2017 , Issue 11 . Art. No.: CD012447. DOI: 10.1002/14651858.CD012447.pub2

Review aim 
The aim of this Cochrane Review was to determine whether surgery for vertical strabismus in people with superior oblique palsy works better than other surgical or non-surgical interventions. We searched for all relevant studies and identified two clinical trials.

Key messages 
There is no high-quality evidence regarding the effects of surgery on vertical strabismus in people with superior oblique palsy. Consequently, we were unable to determine the best surgery for this disorder. Carefully designed studies are needed to enable treatment recommendations for this common problem.

What did we study in this review? 
We compared different types of surgery to reduce vertical strabismus in children and adults with a diagnosis of superior oblique palsy. Superior oblique palsy occurs when there is weakness of one of the muscles (superior oblique) involved in eye movement, causing a characteristic pattern of strabismus, or misalignment of the eyes, that usually varies with head positioning. Superior oblique palsy is a common cause of vertical strabismus, and can lead to double vision or abnormal head positioning in order to maintain single vision.

Main results 
Each of the two included trials compared two different surgical procedures to weaken the inferior oblique muscle, and thus balance the weakness in the superior oblique muscle. A total of four different inferior oblique muscle-weakening surgeries were studied: myectomy (removing part of the muscle), recession (moving the muscle to a position where it exerts less force), anterior transposition (moving the muscle to a position where the direction of force is altered), and disinsertion (detaching the muscle from the sclera).

Neither of the trials examined the main outcome we wished to study, that is the proportion of participants deemed to have successful eye realignment after surgery. Additionally, we judged the quality of the data in both studies to be low.

How up-to-date is this review? 
We searched for trials with outcome data published by 13 December 2016. The included trials were published between 2001 and 2003.