Monday, November 28, 2016

Spinal cord stimulation in experimental chronic painful diabetic polyneuropathy: Delayed effect of High-frequency stimulation

Abstract

Background

Spinal cord stimulation (SCS) has been shown to provide pain relief in painful diabetic polyneuropathy (PDPN). As the vasculature system plays a great role in the pathophysiology of PDPN, a potential beneficial side-effect of SCS is peripheral vasodilation, with high frequency (HF) SCS in particular. We hypothesize that HF-SCS (500 Hz), compared with conventional (CON) or low frequency (LF)-SCS will result in increased alleviation of mechanical hypersensitivity in chronic experimental PDPN.

Methods

Diabetes was induced in 8-week-old female Sprague–Dawley rats with an intraperitoneal injection of 65 mg/kg of streptozotocin (n = 44). Rats with a significant decrease in mechanical withdrawal response to von Frey filaments over a period of 20 weeks were implanted with SCS electrodes (n = 18). Rats were assigned to a cross-over design with a random order of LF-, CON-, HF- and sham SCS and mechanical withdrawal thresholds were assessed with von Frey testing.

Results

Compared with sham treatment, the average 50% WT score for 5 Hz was 4.88 g higher during stimulation (= 0.156), and 1.77 g higher post-stimulation (= 0.008). CON-SCS resulted in 50% WT scores 5.7 g, and 2.51 g higher during (= 0.064) and after stimulation (< 0.004), respectively. HF-SCS started out with an average difference in 50% WT score compared with sham of 1.87 g during stimulation (p = 0.279), and subsequently the steepest rise to a difference of 5.47 g post-stimulation (p < 0.001).

Conclusions

We demonstrated a delayed effect of HF-SCS on mechanical hypersensitivity in chronic PDPN animals compared with LF-, or CON-SCS.

Significance

This study evaluates the effect of SCS frequency (5–500 Hz) on mechanical hypersensitivity in the chronic phase of experimental PDPN. High frequency (500 Hz) – SCS resulted in a delayed effect- on pain-related behavioural outcome in chronic PDPN.



from European Journal of Pain http://ift.tt/2gB3LKj
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