ELECTRICALLY STIMULATED DETRUSOR MYOPLASTY

Background: Many children with spina bifida and other causes for neurogenic bladder rely on clean intermittent catheterization to empty their hyporeflexic or areflexic bladders. Direct bladder and sacral nerve root stimulation have met with limited success. We study the electrical stimulation of a rectus abdominis muscle flap wrapped around the bladder to achieve bladder contractility and emptying. Methods. The rectus abdominis muscle was surgically dissected with preservation of its insertion on the pubis bone and rotation of its midsection behind the bladder to effect a complete bladder wrap. The deep inferior epigastric artery and veins and the two lowermost intercostal nerves were preserved. This unilateral rectus abdominis muscle flap was then electrically stimulated with two pairs of bipolar electrodes inserted into the muscle near the entrance of the nerves. Stimulation frequencies of 40, 60 and 80 hertz were used in each of 8 dogs. The increase in bladder pressure over baseline, half time to muscle fatigue, and percent bladder evacuation were measured. Paired students T-tests were used for statistical comparisons. Results. (Mean [+ or -] SEM) Although half-time to muscle fatigue was different for the 3 stimulation frequencies (p [is less than] 0.05), the increase in bladder pressure and % bladder evacuation were similar (p [is greater than] 0.05). Conclusions. The electrically stimulated detrusor myoplasty results in uniform increases in detrusor pressure and reasonable bladder evacuation in animal model. We are currently studying a detrusor myoplasty in a chronic study to determine whether it can be used for enhanced bladder emptying in children with poor detrusor contractility. Stimulation frequency (Hz) 40 60 Increase bladder pressure 35 [+ or -] 5 45 [+ or -] 6 (cm[H.sub.2]O) Half-time to muscle fatigue (sec) 47 [+ or -] 6 33 [+ or -] 4 Bladder evacuation (%) 73 [+ or -] 8 78 [+ or -] 8 Stimulation frequency (Hz) 80 Increase bladder pressure 45 [+ or -] 7 (cm[H.sub.2]0) Half-time to muscle fatigue (sec) 19 [+ or -] 4 Bladder evacuation (%) 74 [+ or -] 6 Supported by a grant from the Alliant Trust Fund, a non-profit organization. John G. Van Savage, MD, Gustavo Perez-Abadia, MD, Lucio G. Palanca, MD, Richard W. Stremel, PhD, Bruce L. Slaughenhoupt, MD, FAAP, Martin Palacio, MD, FAAP, Gordon Tobin, MD, and Claudio Maldonado, PhD. Divisions of Pediatric Urology, Plastic and Reconstructive Surgery, Department of Surgery, Department of Physiology an