Selective fascicular nerve repair: a rapid method for intraoperative motorsensory differentiation by acetylcholinesterase histochemistry

The selective reunion of motor and sensory fascicles of severed mixed nerves appears indispensible for optimal recovery of the impaired motor function. Procedures available for rapid identification of motor and sensory fascicles rendered ambiguous results. The only highly reliable and simple method marking motor fascicles, namely acetylcholinesterase histochemistry, neccessitated two operations due to its long duration (28 h). In the present study rapid demonstration of acetylcholinesterase activity was accomplished by elevating the temperature and the concentration of 2 constituents of the incubation medium. Now incubation takes 2 h instead of 20 h. Thus, the time necessary for the entire diagnostic procedure could be reduced from 28 h to 4 h. Indeed, intraoperative motorsensory differentiation using acetylcholinesterase activity as a marker appears feasible. The new technique has already been applied to 6 clinical cases of acute nerve injuries of the forearm. The histochemical results obtained are comparable to those of the standard procedure indicating equally high reliability of both methods. Finally, opportunities for further reducing the duration of the modified histochemical procedure and its applicability to fascicular nerve grafting are discussed.