Chemical sympathectomy for neuropathic pain: Does it work? Case report and systematic literature review

Objective: To determine if chemical sympathectomy successfully reduces limb neuropathic pain. Design: Systematic literature review of the effectiveness of phenol or alcohol sympathectomy for extremity neuropathic pain. Patient: A 29-year-old female with complex regional pain syndrome of both lower extremities after back surgery who was submitted to bilateral lumbar chemical sympathectomy. Search strategy: The Cochrane Database of Systematic Reviews, the Cochrane Controlled Trials Register, Medline, and EMBASE were systematically searched. Outcome measures: (1) For the patient in question: spontaneous pain, allodynia, pinprick hyperalgesia, pressure evoked pain; (2) For the literature review: meaningful versus nonmeaningful pain relief based on degree and duration (>2 weeks) of pain relief. Results: (1) The case reported experienced partial temporary relief of pain primarily related to selective modulation of allodynia, but not deep pain or pinprick hyperalgesia; (2) 44% of 66 patients in 13 studies that met the authors' inclusion criteria experienced meaningful pain relief, Whereas 19% experienced no meaningful relief, for the remaining 37% of the patients no conclusions regarding duration and degree of relief could be drawn due to poor reporting of outcomes. Conclusions: Based on the case reported and systematic literature review, chemical sympathectomy seems to have at best a temporary effect, limited to cutaneous allodynia. Despite the popularity of chemical sympatholysis, only few patients and poorly defined outcomes are reported in the literature, substantiating the need for well-designed studies on the effectiveness of the procedure.