Accuracy of botulinum toxin type A injection into the forearm muscles of chronic stroke patients with spastic flexed wrist and clenched fist: manual needle placement evaluated using ultrasonography.

Abstract

To investigate the accuracy of manual needle placement for injection of botulinum toxin type A into the forearm muscles of adults with spastic flexed wrist and clenched fist as a consequence of stroke. Prospective clinical study. A total of 41 adults with chronic stroke who were scheduled to receive botulinum toxin type A injection into the following forearm muscles: flexor carpi radialis, flexor carpi ulnaris, flexor digitorum superficialis and flexor digitorum profundus. According to Huber & Heck's atlas suggestions on treatment of spasticity with botulinum toxin, surface identification of muscles to inject was performed by means of palpation and anatomical landmarks. Accuracy of needle placement and muscle thickness at the site of needle insertion were assessed using ultrasonography. Overall accuracy of manual needle placement evaluated using ultrasonography was 51.2%. Accuracy was significantly higher for the finger flexors than for the wrist flexors (63.4% vs 39.0%). The finger flexors were significantly thicker than the wrist flexors (mean 1.58 vs 0.49 cm). Instrumental guidance should be used in order to achieve an acceptable accuracy of needle placement when performing botulinum toxin type A injections into the forearm muscles of chronic stroke patients with spastic flexed wrist and clenched fist.