Clinical application of intraoperative measurement of choline acetyltransferase activity during functioning free muscle transfer.

Intraoperative measurement of choline acetyltransferase (CAT) activity was used for evaluation of the functional status of donor nerves during functioning free muscle transfer (FFMT). Twelve patients underwent the procedure. Seven patients had a brachial plexus injury, 3 Volkmann's contracture, 1 chronic peroneal nerve injury, and 1 forearm extensor muscle loss after wide resection of soft tissue sarcoma. The purpose of reconstruction using FFMT was to achieve wrist extension in 4 patients, simultaneous elbow flexion and finger extension in 3, elbow flexion in 2, finger extension in 1, finger flexion in 1, and ankle extension in 1 patient. The gracilis muscle was transferred in all cases. The donor nerves for FFMT that were evaluated by CAT activity included 5 spinal accessory nerves, 4 posterior interosseous nerves, 2 anterior interosseous nerves, and 1 deep peroneal nerve. Fascicles with greater than 2,000 cpm CAT activity were considered to reliable and used as donor motor nerves. All muscles had reinnervation by 3.2 months (range, 2-5 months) and obtained useful recovery. Intraoperative measurement of CAT activity can provide direct and quantitative information about the functional status of donor nerves during FFMT.