In pilot work we showed that somatic nerve transfers can restore motor function in long-term decentralized dogs. We continue to explore the effectiveness of motor reinnervation in 30 female dogs. After anesthesia, 12 underwent bilateral transection of coccygeal and sacral (S) spinal roots, dorsal roots of lumbar (L)7, and hypogastric nerves. Twelve months post-decentralization, 8 underwent transfer of obturator nerve branches to pelvic nerve vesical branches, and sciatic nerve branches to pudendal nerves, followed by 10 months recovery (ObNT-ScNT Reinn). The remaining 4 were euthanized 18 months post-decentralization (Decentralized). Results were compared to 18 Controls. Squat-and-void postures were tracked during awake cystometry. None showed squat-and-void postures during the decentralization phase. Seven of 8 ObNT-ScNT Reinn began showing such postures by 6 months post-reinnervation; one showed a return of defecation postures. Retrograde dyes were injected into the bladder and urethra 3 weeks prior to euthanasia, at which point, roots and transferred nerves were electrically stimulated to evaluate motor function. Upon L2-L6 root stimulation, 5 of 8 ObNT-ScNT Reinn showed elevated detrusor pressure and 4 showed elevated urethral pressure, compared to L7-S3 root stimulation. After stimulation of sciatic-to-pudendal transferred nerves, 3 of 8 ObNT-ScNT Reinn showed elevated urethral pressure; all showed elevated anal sphincter pressure. Retrogradely labeled neurons were observed in L2-L6 ventral horns (in laminae VI, VIII and IX) of ObNT-ScNT Reinn, versus Controls in which labeled neurons were observed in L7-S3 ventral horns (in lamina VII). This data supports the use of nerve transfer techniques for restoration of bladder function.
Keywords: Bladder; Detrusor Pressure; Functional Electrical Stimulation; Motor Neuron; retrograde dye.