Spinal cord stimulation in a mouse chronic neuropathic pain model

Objective.  Development of a spinal cord stimulation (SCS) system in a mouse model of chronic neuropathic pain. Materials and Methods.  Male C57BL/6 mice (N = 6) underwent a partial ligation of the sciatic nerve. Development of mechanical hyperalgesia was tested using the withdrawal response to tactile stimuli with the von Frey test. An SCS system was implanted on day 14. On day 16, the mice were stimulated for 30 min (f = 50 Hz; pulse width 0.2 msec and stimulation at 2/3 of motor threshold). Repeated measure analysis of variance (anova) and paired Student's t-test with Bonferroni correction were used to evaluate the development of mechanical hyperalgesia and the therapeutic effect of SCS. Results.  Five out of six mice developed marked mechanical hyperalgesia in the nerve-lesioned paw that persisted for the duration of the study (16 days). No changes contralateral to the injury were observed. In four out of five mice, a successful implantation of the electrodes followed by stimulation was achieved. Then, SCS resulted in a fast and robust increase of withdrawal threshold back to pre-injury levels. After termination of the SCS, the withdrawal threshold of the ipsilateral paw slowly decreased. No effect of SCS on the contralateral paw was noted. Conclusion.  The development of a mouse SCS system is described that is practical in use, is reproducible, and shows a comparative therapeutic effect in treatment of chronic neuropathic pain as reported in rat.