OBJECT: The authors investigated the causes for surgical reexploration in patients with complex regional pain syndrome Type II who received initial relief of pain from implantation of a peripheral nerve stimulator (PNS). METHODS: The authors reviewed the charts of 11 consecutive patients who underwent a total of 27 PNS-related operations at one institution. Duration of follow up ranged from 5 days to more than 24 months. Of 11 patients who received PNS implants, seven (64%) required one or more additional surgeries to relocate the PNS because initial pain relief following stimulation was lost and not restored by changing pulse generator settings. Loss of analgesia was attributed to migration of the sutured electrode strip paddle (nine [33%] of 27 surgeries), infection (four [15%] of 27), and the need for placement in an alternative location (three [11%] of 27). CONCLUSIONS: Although infection is attributable to surgical technique, most complications requiring repeated surgery (nine [33%] of 27) are caused by equipment design. Changes in PNS design or in implantation technique might substantially reduce the need for reoperation after PNS implantation.