Abstract
Abstract: :
Purpose: To determine incidence and characteristics of a newly described cause of late over- or undercorrection after strabismus surgery: the stretched scar. Methods: This is a retrospective chart review of all patients diagnosed with stretched scar at the time of re-operation strabismus surgery performed by one of the authors (KWW) over a 16-month period between 6/2000 and 10/2001. The diagnosis of stretched scar was made at the time of surgery based on the appearance of the muscle-scleral attachment. Results: Nine of 76 (12.5%) patients who underwent a re-operation strabismus surgery were identified as having a stretched scar as the cause for their consecutive or residual strabismus. Two of the nine stretched scar patients had their primary surgery performed by one of the authors (KWW) and the rest had their primary surgery elsewhere. The age range was 10 yrs to 78 yrs, with 4 males and 5 females. Onset of deviation secondary to stretched scar was documented in 5 patients, and ranged from 3 weeks to 8 years with 4 of the 5 patients developing stretched scar within 3 months of surgery. Preoperative ductions were normal in 1 patient, -1 in 5 patients, -2 in 2 patients, and - 3 in 1 patient. Two patients had bilateral stretched scars. Muscles involved were: 8 medial recti, 2 lateral recti, and 1 inferior rectus. Two of the 11 afffected muscles were on adjustable suture. One patient had a resection procedure, while 8 had a recession procedure. Pathology of a stretched medial rectus muscle insertion was obtained on 1 patient. This patient had onset of the stretched scar 3 weeks after primary surgery with subsequent corrective surgery and biopsy at 3 months. Pathology showed fibrous tissue with scant muscle fibers, minimal foreign material, foreign body giant cell reaction, and scant focal perivascular lymphocytes. Conclusion: Stretched scar is an important cause of unfavorable outcome after strabismus surgery. It occurs late, at least 3 weeks after surgery, in contrast to a slipped muscle that occurs immediately after surgery. Cause may be related to loss of suture strength in some cases. Ductions are often minimally affected, so the diagnosis can be easily missed.
Keywords: 588 strabismus • 591 strabismus: treatment • 590 strabismus: etiology