title: Pressure changes under the ischial tuberosities during gluteal neuromuscular stimulation in spinal cord injury: a comparison of sacral nerve root stimulation with surface functional electrical stimulation.
abstract: OBJECTIVE
  To compare the magnitude of interface pressure changes during gluteal maximus contraction by stimulating sacral nerve roots with surface electrical stimulations in patients with spinal cord injuries (SCIs).
  
  
  METHODS
  Pilot interventional study.
  
  
  METHODS
  Spinal injury research laboratory.
  
  
  METHODS
  Adults (N=18) with suprasacral complete SCI.
  
  
  METHODS
  Sacral nerve root stimulation (SNRS) via a functional magnetic stimulator (FMS) or a sacral anterior root stimulator (SARS) implant; and surface functional electrical stimulation (FES).
  
  
  METHODS
  Interface pressure under the ischial tuberosity (IT) defined as peak pressure, gradient at peak pressure, and average pressure.
  
  
  RESULTS
  With optimal FMS, a 29% average reduction of IT peak pressure was achieved during FMS (mean ± SD: 160.1±24.3mmHg at rest vs 114.7±18.0mmHg during FMS, t5=6.3, P=.002). A 30% average reduction of peak pressure during stimulation via an SARS implant (143.2±31.7mmHg at rest vs 98.5±21.5mmHg during SARS, t5=4.4, P=.007) and a 22% average decrease of IT peak pressure during FES stimulation (153.7±34.8mmHg at rest vs 120.5±26.1mmHg during FES, t5=5.3, P=.003) were obtained. In 4 participants who completed both the FMS and FES studies, the percentage of peak pressure reduction with FMS was slightly greater than with FES (mean difference, 7.8%; 95% confidence interval, 1.6%-14.0; P=.04).
  
  
  CONCLUSIONS
  SNRS or surface FES can induce sufficient gluteus maximus contraction and significantly reduce ischial pressure. SNRS via an SARS implant may be more convenient and efficient for frequently activating the gluteus maximus.
authors.affiliation: Department of Adult, Child and Midwifery, School of Health and Education, Middlesex University, London, United Kingdom. Electronic address: L.Q.Liu@mdx.ac.uk.
authors.forename: Liang Qin
authors.initials: LQ
authors.lastname: Liu
authors.affiliation: Faculty of Rehabilitation, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Martin
authors.initials: M
authors.lastname: Ferguson-Pell
mesh_terms: D000328:Adult; D002081:Buttocks; D004599:Electric Stimulation Therapy / Q000379:methods*; D006801:Humans; D008161:Lumbosacral Region; D055909:Magnetic Field Therapy / Q000379:methods*; D008875:Middle Aged; D009119:Muscle Contraction; D026741:Physical Therapy Modalities; D003668:Pressure Ulcer / Q000517:prevention & control; D013119:Spinal Cord Injuries / Q000534:rehabilitation*
keywords: Electric stimulation; Pressure ulcer; Rehabilitation; Spinal cord injuries