DETRUSOR-MYOPLASTY, INNERVATED RECTUS MUSCLE TRANSPOSITION STUDY, AND FUNCTIONAL EFFECT ON THE SPINAL-CORD INJURY RAT MODEL

The purpose of this investigation was to determine the feasibility of striated muscular augmentation of the urinary bladder (detrusor-myoplasty, DMP). Initial studies, transposition, and bladder wrap using several distinct muscle groups was attempted in laboratory rats, goats, and fresh human cadavers. The rectus abdominus muscle was found to be best suited to completely encompass the bladder with an intact neural and vascular supply. The technique was then applied in a rat model of spinal cord injury (SCI). Modified Tarlov ratings were employed to assess neurologic function 30 days after SCI. The median final neurological score of SCI rats with and without DMP was 4 and 5, respectively. Sham-operated SCI (control) rats, with and without DMP, both had normal final Tarlov scores of 12 (P < 0.05). Muscle blood flow values for the flap and the contralateral undissected rectus muscles were not significantly different (97 +/- 34 and 105 +/- 40 ml/100 g tissue/min, respectively, P = 0.47). Postoperatively, no bowel or abdominal wall functional deficits were apparent. The rotated muscular flap remained innervated and vascularized. Analysis of 24 hr micturition patterns demonstrated no differences in oral fluid intake/24hr, voided volume/24hr, and ratio of number of micturitions.during the night vs. day among the four groups: (1) control (neither SCI nor DMP), (2) DMP only, (3) SCI only, and (4) SCI with DMP. Spinal cord injured rats with and without detrusor-myoplasty demonstrated a significant decrease in the number of micturitions/24hr, an increased volume per micturition, and greater largest and smallest micturition volumes (P < 0.05) when compared to controls. The micturition patterns among SCI rats with and without DMP were similar, as were non-SCI animals with and without DMP. This is the first report of the principle and technique of detrusor-myoplasty. Dissection of rats, goats, and human cadavers revealed that a vascularized and innervated rectus muscle flap can be rotated into the pelvis and wrapped around the bladder without tension. Significant loss of bladder capacity did not occur with skeletal muscle adaptation. Detrusor-myoplasty may be applicable for patients with an areflexic detrusor and non-intact sacral motor roots who are not candidates for sacral anterior root neurostimulation. (C) 1994 Wiley-Liss, Inc.