Diagnostic blocks of the tibial nerve in spastic hemiparesis. Effects on clinical, electrophysiological and gait parameters

The value of a diagnostic block (DB) of the tibial nerve in 17 hemiparetic patients with gait disturbances was investigated. The purpose of this study was to find instruments that help to select patients who will benefit from a long lasting peripheral nerve block. The manually elicited ankle clonus and its abolition after injection of a local anaesthetic appeared to be a useful clinical test for the efficacy of DB. Electrophysiological tests proved valuable when DB failed to produce clinical effects. With a substantial number of blocked nerve fibres walking velocity did not deteriorate. Transient disturbances in sensation can be regarded as unwanted side effects that might adversely affect the walking ability. From the different aspects of gait an improved heelcontact demonstrated the functional gain in patients with a dynamic equinus foot. To differentiate between a dynamic equinus foot and fixed contractures, we recommend the use of a fast acting local anaesthetic for diagnostic nerve blocks.