Construction of a urinary sphincter by means of an electrically stimulated striated muscle: experimental procedure and urodynamic results on canine model.
A canine model of urinary neosphincter using electrically stimulated autologous striated muscle is described. The superior belly of canine sartorius was activated by a pacemaker with an intermittent low frequency stimulation (0.5-1 pulse per sec) during 7 weeks. Then, the muscle graft was passed around the urethra and sutured back on to itself to form a neosphincter. The surgical procedure was easy to perform and with no complication. Urethral pressure profile was performed initially (T0), and when the muscle was in peri-urethral position, before (T1) and during electrical stimulation (T2). The continence parameter readings (maximal urethral closure pressure MUP, functional length FL, continence zone CZ, and continence area CA) increased from T0 to T1, and from T1 to T2. We noted: 1) 28%, 38%, 52%, and 86% increases for the MUP, FL, CZ, and CA respectively from T0 to T1, 2) 10%, 41%, 30%, and 43% increases for MUP, FL, CZ, and CA respectively from T1 to T2. Chronic low frequency stimulation could transform a skeletal fast-twitch type 2 muscle into a slow-twitch fatigue-resistant type 1 muscle. In this study, morphological changes of the stimulated muscle were noted, whereas phenotype was unchanged. This dynamic autologous neosphincter may be a new alternative to the artificial urinary sphincter prosthesis with fewer complications. Further studies are ongoing to evaluate the efficacy of such a neosphincter as continent system for bladder substitution after pelvic exenteration for pelvic cancers.
Bladou
F
F
Department of Surgery, Institut Paoli Calmettes, marseille, France.
Houvenaeghel
G
G
Delpero
J R
JR
Monges
G
G
Serment
G
G
Guerinel
G
G
D000818:Animals; D004285:Dogs; D004599:Electric Stimulation Therapy; D005260:Female; D018482:Muscle, Skeletal / Q000502:physiology / Q000637:transplantation*; D014521:Urethra / Q000601:surgery*; D014549:Urinary Incontinence / Q000601:surgery*; D016741:Urinary Sphincter, Artificial; D014563:Urodynamics / Q000502:physiology*