title: Neuromodulation through sacral nerve roots 2 to 4 with a Finetech-Brindley sacral posterior and anterior root stimulator.
abstract: METHODS
  Investigation of five patients receiving an implant, using laboratory cystometry and self-catheterisation at home.
  
  
  OBJECTIVE
  To use the established Finetech-Brindley sacral root stimulator to increase bladder capacity by neuromodulation, eliminating the need for posterior rhizotomy, as well as achieving bladder emptying by neurostimulation.
  
  
  METHODS
  Spinal Injuries Unit, Royal National Orthopaedic Hospital, Stanmore, Middlesex, UK.
  
  
  METHODS
  Five patients underwent implantation of a Finetech-Brindley stimulator without rhizotomy of the posterior roots. This was either a two channel extradural device (four cases) or a three channel intrathecal device (one case). In each patient, the implant was configured as a Sacral Posterior and Anterior Root Stimulator (SPARS). Postoperatively, repeated provocations using rapid instillation of 60 ml saline were used to determine the relative thresholds for neuromodulation using each channel. The effect of continuous neuromodulation was examined in the laboratory using slow fill cystometrograms, and conditional stimulation was also studied (neuromodulation for 1 min to suppress hyperreflexic contractions as they occurred). In one patient, neuromodulation was applied continuously at home, and volumes at self catheterisation recorded in a diary.
  
  
  RESULTS
  Reflex erections were preserved in each patient. In three patients, detrusor hyperreflexia persisted postoperatively and neuromodulation via the implant was studied. In these three patients, the configuration was: S2 mixed roots bilaterally (channel B), and S34 bilaterally (channel A). Both channels could be used to suppress provoked hyperreflexic contractions, with the S2 channel effective at a shorter pulse width than S34 in a majority of cases. Continuous stimulation more than doubled bladder capacity in two out of three patients during slow fill cystometry. Conditional stimulation was highly effective. In the one patient who used continuous stimulation at home, bladder capacity was more than doubled and the effect was comparable with anticholinergic medication. Bladder pressures >70 cm water could be achieved with intense stimulation in three patients, but detrusor-external urethral sphincter dyssynergia (DSD) prevented complete emptying.
  
  
  CONCLUSIONS
  Neuromodulation via a SPARS was effective and may replace the need for posterior rhizotomy. However, persisting DSD may prevent complete bladder emptying and warrants further investigation.
authors.affiliation: Neuroprostheses Research Centre, Spinal Injuries Unit, Royal National Orthopaedic Hospital, Stanmore, Middlesex HA7 4LP, UK.
authors.forename: A P S
authors.initials: AP
authors.lastname: Kirkham
authors.forename: S L
authors.initials: SL
authors.lastname: Knight
authors.forename: M D
authors.initials: MD
authors.lastname: Craggs
authors.forename: A T M
authors.initials: AT
authors.lastname: Casey
authors.forename: P J R
authors.initials: PJ
authors.lastname: Shah
mesh_terms: D000328:Adult; D004599:Electric Stimulation Therapy / Q000295:instrumentation / Q000379:methods*; D004567:Electrodes, Implanted; D005069:Evaluation Studies as Topic; D006801:Humans; D007796:Laminectomy / Q000009:adverse effects; D008297:Male; D010410:Penile Erection / Q000502:physiology; D010413:Penis / Q000294:innervation / Q000503:physiopathology; D011183:Postoperative Complications / Q000503:physiopathology*; D012021:Reflex, Abnormal / Q000502:physiology; D019051:Rhizotomy; D012447:Sacrum / Q000294:innervation*; D012680:Sensitivity and Specificity; D013119:Spinal Cord Injuries / Q000150:complications / Q000601:surgery; D013126:Spinal Nerve Roots / Q000503:physiopathology*; D013904:Thoracic Vertebrae / Q000601:surgery; D001743:Urinary Bladder / Q000503:physiopathology*; D014549:Urinary Incontinence / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D014563:Urodynamics / Q000502:physiology