The use of an image guidance system in retrieving lost medial rectus muscles

Abstract

Introduction: Finding a lost medial rectus muscle can be difficult. We present 2 patients in whom image guidance technology assisted in the recovery of a lost medial rectus muscle. Methods: Two patients (ages 19 and 33), both with lost medial rectus muscles, underwent computerized tomography of their heads, faces, and orbits. The muscles were both lost after strabismus surgery 7 and 19 years ago, respectively. These images were then loaded into an image guidance system (LandmarX, Xomed Co, Jacksonville, Fla) and served as a “map” to locate the lost medial rectus muscle intraoperatively. Using a transnasal endoscopic approach, the lamina papyracea was exposed. The area of the lamina closest to the lost medial rectus was identified using a guidance probe. After the periorbita was exposed, the guidance probe was used to confirm the location of the medial rectus muscle. The muscle was then isolated transnasally and passed into the orbit using forceps. It was then sutured onto the globe. Results: The medial rectus was identified transnasally and reattached to the globe in both cases. Adduction improved from complete deficits in both patients to 80% and 50% adduction deficits, respectively. Discussion: The transnasal endoscopic approach to retrieve the medial rectus has been described before. For these patients, image guidance technology successfully identified the appropriate areas for the surgeons to locate the lost muscle. The use of this technique decreased operative times and reduced the extent of the dissection required, which should also reduce long–term scarring. Conclusion: Image guidance technology, with its capability of 3–dimensional images, can be used to assist surgeons in finding lost medial rectus muscles. (J AAPOS 2002;6:309-14)