On the applicability of two different stimulation techniques for intra-operative peroneal nerve conduction testing

Dysfunction of the peroneal nerve is an important complication of knee surg ery. We compared two monitoring procedures of peroneal nerve Function durin g a standardized operation, a closing wedges high tibial osteotomy. For two types of stimulation the evoked compound motor unit action potentials (CMA Ps) were recorded on the tibialis anterior muscle. We used direct perineura l electrical stimulation of the common peroneal nerve distal to the cuff (d CMAPs) after nerve identification in tile surgical field. Additionally, mag netic stimulation of the sacral plexus proximal to the cuff (pCMAPs) was pe rformed. It was found that dCMAPs were recorded during almost one hour of t ourniquet tints whereas the pCMAPs were blocked after 25-30 min in 9 out of 11 cases. On the other hand, the CMAP obtained after proximal stimulation exhibited a latency shift with tourniquet yielding an indicator of ischaemi c changes present beneath and distal to the tourniquet cuff. In conclusion, different applicabilities of both stimulation techniques under tourniquet conditions were demonstrated. (C) 2001 Orthopaedic Research Society. Publis hed by Elsevier Science Ltd. All rights Reserved.