Pressure changes under the ischial tuberosities of seated individuals during sacral nerve root stimulation

Abstract

Abstract-Neuromuscular stimulation via the sacral nerve roots is proposed for prevention of ischial pressure ulcers following a spinal cord injury (SCI). Acute effects of sacral functional magnetic stimulation (FMS) on seat interface pressure changes were investigated in five nondisabled volunteers. Similar effects were demonstrated with functional electrical stimulation in people with SCI who used a sacral anterior root stimulator implant. The results indicated that sacral nerve root stimulation, either by FMS or implanted electrical stimulation, induced gluteus maximus contraction and mild pelvic tilt sufficient for clinically significant reductions in ischial pressures during sitting.

Interface pressure and cutaneous hemoglobin and oxygenation changes under ischial tuberosities during sacral nerve root stimulation in spinal cord injury

“…Recently, we used FMS to investigate the dynamic effects of sacral nerve root stimulation on ischial pressure changes in nondisabled people. Our results demonstrated that ischial pressure significantly decreased during optimal stimulation [23]. However, we reported neither the effects of FMS on people with SCI nor the tissue hemodynamic changes during FMS.…”

“…During optimal magnetic stimulation in the noninvasive magnetic stimulation study, maximum effects were obtained at the approximately S2 foramen level in all five subjects with SCI, which corresponds to a study on FMS in nondisabled people [23]. With electrical stimulation through the SARS implant, maximum reduction in peak pressure was obtained when the S2 nerve was stimulated with a pulse width between 64 and 600 μs, a frequency of 20 pps, and an amplitude of "1.…”

“…The optimal coil position for sacral nerve root stimulation was determined by mapping the gluteal muscle response [22][23]. The coil was placed over various points of a grid pattern that ranged from the level of the iliac crest to 10 cm below and 8 cm to either side of midline.…”

“…Alternatively, an implanted sacral nerve electrical stimulator device may be a more practical solution especially if its utility can be demonstrated noninvasively. For this purpose, noninvasive functional magnetic stimulation (FMS) of the sacral nerve roots can effectively and noninvasively contract gluteal and pelvic floor muscles [22][23]. FMS has advantages over surface FES because of its noninvasive deep penetration.…”

Sacral rhizotomy: a salvage procedure in a patient with autonomic dysreflexia

“…1,4 In selected patients, sacral deafferentation without implantation of an anterior root stimulator has been proven to be clinically useful as well. 5 If patients decide to undergo rhizotomy without receiving a stimulator, bowel evacuation and erectile function may become a problem, as reflex activity can be impaired by surgery.…”