The effect of spinal cord stimulation frequency in experimental painful diabetic polyneuropathy

Background Spinal cord stimulation (SCS) has been shown to be an effective treatment for painful diabetic polyneuropathy (PDP). An increase of efficacy is needed since only 67% of patients benefit from SCS. This study aimed to develop an animal model for SCS in PDP and study the effect of various stimulation frequencies on the functional outcome. As the pathophysiology of PDP is complex, including vasoconstriction and nerve injury, the frequency of SCS may result in different outcomes. Methods Diabetes mellitus was induced by an intraperitoneal injection of streptozotocin in 8-week-old female Sprague-Dawley rats (n=76;glucose >15mmol/L; n=51). A SCS device was implanted at level Th13 4 weeks later. SCS of the dorsal columns was applied for 30min and the effect on mechanical hypersensitivity was evaluated. Results Mechanical hypersensitivity developed in 26 rats, which were included (low-frequency, n=6; mid-frequency, n=8; high frequency, n=9; and sham, n=3). SCS of the dorsal columns was applied for 40min, and the effect on mechanical hypersensitivity was evaluated. In all treatmentgroups, SCS resulted in reversal of mechanical hypersensitivity and a clinically relevant reduction was achieved in 70% of animals. No differences in efficacy were found between the different treatment groups. Conclusions The pain-relieving effect of SCS in PDP was studied in an experimental model. Our study shows that SCS on mechanical hypersensitivity in PDP rats is equally effective when applied at low, mid and high frequency.