Influence of Sacral and Thoracolumbar Spinal Nerve Electrical Stimulation on Colonic Motility in Anesthetized Yucatan...

Colon displays structural and functional diversity. However, the region-specific motility effects of spinal nerves on the colon are unclear. We mapped the regional colonic motor response to thoracolumbar (T12-L1) (TLNS) and sacral (S1-S4) (SNS) roots nerve electrical stimulation (ES) in an anesthetized porcine model, with or without concomitant afferent (AB) or efferent (EB) transmission block.

Adult male Yucatan pigs (n = 16) underwent a laminectomy followed by unilateral (left root) SNS (S1-S4, 30 Hz, 0.3 ms, 0.5 mA, PT, 30 s ON/90 s OFF) or with concomitant AB or EB (40 kHz, 0.1 ms, 2 mA). In a separate group (n = 7), TLNS (T12-L1, 10 Hz, 0.3 ms, 0.5 mA, continuous or 30 Hz, 0.3 ms, 0.5 mA, PT, 30 s ON/90 s OFF) of the left root concomitant with or without EB was applied. Proximal (pC), transverse (tC), distal (dC) colon and anal canal (AC) luminal manometry were monitored before, during and after stimulation. Area under the curve of contraction (AUC), luminal pressure heat maps, and contraction spectral analysis were analyzed.

S2 ES increased the power of the contraction frequency spectrum in both dC and AC during stimulation and increased the AUC of contraction in dC and AC during and post-stimulation. AB and EB partially reduced dC, while EB abolished the increase in AC. In contrast, S1, S3, or S4 ES as well as TLNS had little effect on motility.

In anesthetized male pigs, S2 ES induces a robust motility response in the distal colon via the central network while in the anal canal via efferent pathways.