Clinical Trial of the Safety and Efficacy of Peripheral Nerve Stimulation in the Treatment of Peripheral Neuropathic Pain.

The investigators divide study process into 3 main periods called enrollment/baseline period, treatment period and follow-up period. The treatment period is classified into test period, randomized withdrawal period and observation period further. 1. Enrollment/baseline period This study will be conducted at four clinical trial sites in China with 3 to 6 subjects included in the pretest and the formal trial planned to enroll 56 subjects. All subjects enter screening process after signing the informed consent form (ICF) approved by the ethics committee. Subjects are enrolled who meet inclusion criteria and do not meet any exclusion criteria. Enrolled subjects will undergo vital signs, physical examination, laboratory tests, and visual analogue scale (VAS) scores for pain for at least 4 days, Neuropathic Pain Scale (DN4), and the Short Form Health Survey (SF-36) as part of the screening period assessment prior to electrode implantation. 2. Treatment period 2.1 Implantation of devices Enrolled subjects are implanted with the percutaneous peripheral nerve stimulation system, which was parameterized by the investigator via a programmable controller. Subjects are provided with a "Transcutaneous Peripheral Nerve Stimulation Remote Control Instruction Manual" to guide them in the proper operation and use of the system. 2.2 Test period Investigators will adjust stimulation parameters and record VAS score under different parameters conditions. The enrolled subjects are provided 1 to 5 stimulation therapy patterns parameterized by investigators after the test. Then the subjects receive continuous stimulation with parameterized patterns of 7 (±3) days and VAS scores are be recorded every day of 7 days. Subjects will enter next stage if their VAS scores decrease more than 30% from baseline level or withdraw the trial as reduction less than 30% and devices are removed. 2.3 Randomized withdrawal period Subject will be classified into random group. One of the group receiving active stimulation called trial group and another receiving placebo stimulation called control group. Both of two groups are performed stimulation in the next 7 days. The subjects of control group will get active stimulation again as the VAS scores back to and maintain 2 days at baseline level. VAS scores will be recorded every day during this period. 2.4 Observation period The devices are on work until 28th day after the implantation in trial group; stimulators are turned on after randomized withdrawal period until 28th day after the implantation in control group. All subjects have electrode leads removed on day 28 of implantation or at early withdrawal. 3. Follow-up period Investigators will begin follow up as the removal of electrode leads or on the day 28 of implantation. Indicators including VAS score will be evaluated and recorded to assess the efficacy and safety of percutaneous peripheral nerve stimulation during follow-up.