DETRUSOR-MYOPLASTY, INNERVATED RECTUS MUSCLE TRANSPOSITION STUDY, ANDFUNCTIONAL 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-myopla sty, DMP). Initial studies, transposition, and bladder wrap using seve ral distinct muscle groups was attempted in laboratory rats, goats, an d fresh human cadavers. The rectus abdominus muscle was found to be be st suited to completely encompass the bladder with an intact neural an d vascular supply. The technique was then applied in a rat model of sp inal cord injury (SCI). Modified Tarlov ratings were employed to asses s neurologic function 30 days after SCI. The median final neurological score of SCI rats with and without DMP was 4 and 5, respectively. Sha m-operated SCI (control) rats, with and without DMP, both had normal f inal Tarlov scores of 12 (P < 0.05). Muscle blood flow values for the flap and the contralateral undissected rectus muscles were not signifi cantly different (97 +/- 34 and 105 +/- 40 ml/100 g tissue/min, respec tively, P = 0.47). Postoperatively, no bowel or abdominal wall functio nal deficits were apparent. The rotated muscular flap remained innerva ted and vascularized. Analysis of 24 hr micturition patterns demonstra ted no differences in oral fluid intake/24hr, voided volume/24hr, and ratio of number of micturitions.during the night vs. day among the fou r groups: (1) control (neither SCI nor DMP), (2) DMP only, (3) SCI onl y, and (4) SCI with DMP. Spinal cord injured rats with and without det rusor-myoplasty demonstrated a significant decrease in the number of m icturitions/24hr, an increased volume per micturition, and greater lar gest and smallest micturition volumes (P < 0.05) when compared to cont rols. The micturition patterns among SCI rats with and without DMP wer e similar, as were non-SCI animals with and without DMP. This is the f irst report of the principle and technique of detrusor-myoplasty. Diss ection 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 bladde r capacity did not occur with skeletal muscle adaptation. Detrusor-myo plasty may be applicable for patients with an areflexic detrusor and n on-intact sacral motor roots who are not candidates for sacral anterio r root neurostimulation. (C) 1994 Wiley-Liss, Inc.