Clinical features, Management and Surgical outcome for Strabismus with Long Standing Slipped or Lost muscles; Report of 18 Cases

Abstract

Abstract: : Purpose:To describe the preoperative clinical features, intraoperative management and surgical outcome of patients with chronically slipped or lost muscles. Methods: We reviewed the charts of all patients operated in the past 4 years and who had a diagnosis of slipped or lost rectus muscle either related to previous strabismus surgery or trauma. All patients had at least one–year duration between the last surgery or trauma and the time of presentation. Preoperative data included the deviation using the prism and alternative cover test in the diagnostic positions of gaze and clinical assessment of versions and ductions. Postoperatively, alignment in the primary position and duction limitation in the field of action of the slipped or lost muscle at the last follow up examination were specifically evaluated. Results:The average age of the patients at the time of the presentation was 28 years (from 6 to 73 years). A total of 17 muscles were slipped and two muscles were lost. The average duration between the time of the event that lead to the slipped or lost muscles and time of presentation was 12 years (1 to 50 years). The mean duration of follow up after surgery was 5.5 month (1 to 24 month). Preoperatively, the mean of duction limitation in the field of action of the slipped or lost muscle was –1 (0 to –3). Four patients (22%) had normal ductions and 7 (38%) had minimal duction limitation of –0.5. All but one patient was corrected with one surgery. All slipped and lost muscles were advanced anteriorly as guided by the results of intraoperative traction testing. Eight of the 18 (44%) patients were orthotropic at the last follow up examination. The remaining patients had primary position alignment within 10 prism diopters of orthotropia. The mean of duction limitation in the field of action of the slipped or lost muscle at last follow up was –0.3 (0 to –2). Conclusions: Patients with chronically slipped or lost muscles may not always show the typical criteria of slipped or lost muscles. Duction limitation in the field of action of the involved muscle was the most common sign of slipped or lost muscle preoperatively. In chronic cases, advancing the muscle anteriorly as guided by the results of inraoperative traction testing yielded good results.

Keywords: strabismus • strabismus: treatment • strabismus: diagnosis and detection