Torsion and pattern strabismus: potential conflicts in treatment.

Importance: Rectus muscle transposition to treat pattern strabismus or torsion may have an adverse outcome if the surgeon is unaware that it will affect both pattern strabismus and torsion in contradictory ways.

Objective: To highlight the potential adverse affects of rectus muscle transposition on torsion or pattern strabismus.

Design And Participants: A retrospective nonblinded medical record review of patients treated by the author between January 1, 1990, and June 30, 2009, in whom rectus muscle transposition to address pattern strabismus worsened torsion, or in whom transposition to address torsion worsened pattern strabismus. The main outcome was a worsening of either torsion or pattern strabismus.

Setting: A tertiary care university referral center.

Intervention: Rectus muscle transposition surgery to either treat pattern strabismus or torsion.

Main Outcome Measures: The presence of new or worsened pattern strabismus or torsion. The outcome measures were determined before data collection began.

Results: Eight patients were identified by the review, 5 in whom torsion developed because of transposition to address pattern strabismus and 3 in whom pattern strabismus developed after transposition to address torsion. The presence of bifoveal fusion and/or Graves orbitopathy were risk factors for these adverse outcomes.

Conclusions And Relevance: Rectus muscle transposition to address pattern strabismus may cause torsion, and transposition to address torsion may cause pattern strabismus.