Botulinum toxin A for neuropathic pain after neck dissection: a dose-finding study.

OBJECTIVES: Botulinum toxin type A (BtxA) has been reported to be feasible in chronic neuropathic pain after neck dissection. The impact of the dose on the outcome has not been investigated yet.

STUDY DESIGN: Twenty-three patients with neuropathic pain after neck dissection were selected for an open and prospective phase II trial.

METHODS: In the low-dose group (n=13), a concentration of 10 mouse units (MU)/0.1 mL saline and in the high-dose-group (n=10), a concentration of 20 MU/0.1 mL saline were injected subcutaneously. Pain and quality of life were assessed at day 0 and day 28, respectively, by visual analog scales (VAS) and European Organization for Research and Treatment of Cancer (EORTC) quality-of-life core and EORTC quality-of-life head and neck module questionnaires.

RESULTS: Patients in the low-dose group showed a significant pain reduction (VAS) from 4.3 at day 0 to 3.0 at day 28 (P<.05). The mean pain VAS values in the high-dose group did not improve significantly. No serious adverse events were observed. There were trends toward improvement in quality of life in the low-dose group.

CONCLUSIONS: BtxA in a low concentration seems to be a useful therapeutic option in chronic neuropathic pain of the neck and shoulder after neck dissection.