Long-Term Spinal Cord Stimulation Alleviates Mechanical Hypersensitivity and Increases Peripheral Cutaneous Blood Perfusion in Experimental Painful Diabetic Polyneuropathy

ObjectivesThis study utilizes a model of long-term spinal cord stimulation (SCS) in experimental painful diabetic polyneuropathy (PDPN) to investigate the behavioral response during and after four weeks of SCS (12 hours/day). Second, we investigated the effect of long-term SCS on peripheral cutaneous blood perfusion in experimental PDPN. MethodsMechanical sensitivity was assessed in streptozotocin induced diabetic rats (n=50) with von Frey analysis. Hypersensitive rats (n=24) were implanted with an internal SCS battery, coupled to an SCS electrode covering spinal levels L2-L5. The effects of four weeks of daily conventional SCS for 12 hours (n=12) or Sham SCS (n=12) were evaluated with von Frey assessment, and laser Doppler imaging (LDI). ResultsAverage paw withdrawal thresholds (PWT) increased during long-term SCS in the SCS group, in contrast to a decrease in the Sham group (Sham vs. SCS; p=0.029). Twenty-four hours after long-term SCS average PWT remained higher in the SCS group. Furthermore, the SCS group showed a higher cutaneous blood perfusion during long-term SCS compared to the Sham group (Sham vs. SCS; p=0.048). Forty-eight hours after long-term SCS, no differences in skin perfusion were observed. DiscussionWe demonstrated that long-term SCS results in decreased baseline mechanical hypersensitivity and results in increased peripheral blood perfusion during stimulation in a rat model of PDPN. Together, these findings indicate that long-term SCS results in modulation of the physiological circuitry related to the nociceptive system in addition to symptomatic treatment of painful symptoms.