Reconstruction of Severed Dorsal Roots Innervating the Urinary Bladder: An Experimental Study in Cats II. Regeneration studies

Abstract

In an experimental study on 12 adult female cats, the dorsal sacral roots mediating the afferent inflow of the pelvic and pudendal nerves were transected. In 4 animals, the S₁ dorsal roots transected immediately distally to their ganglia were anastomosed with tubulation technique to the peripheral part of the transected S₂ radicular nerves. In 5 animsals anastomoses were performed between the L₇ dorsal roots and the S₁ radicular nerves, thus creating a non-physiological afferent pathway to the urinary bladder. In 3 control animals all sacral dorsal roots were transected but no anastomoses were performed. The functional restitution of afferent fibers was assessed by the return of the micturition reflex and storage reflexes. The micturition reflex returned in the cystometrograms of 5 of 9 animlals with reconstructed dorsal roots after regeneration periods ranging between 8 and 11 months. The storage reflexes were present in approximately half of the animals with root anastomoses tested in final experiments with afferent electrical stimulati'on of the pelvic or pudendal nerves. Recovery of the micturition reflex and storage reflexes was demonstrated both in animals with S₁-S₂ anastomoses and in animals with L₇-S₁ anastomoscs. In the control animals and in animals where functionally regenerated roots were transected, the micturition reflex and the storage reflexes were abolished. Regeneration was further evaluated by recording of propagalted action potentials from reconstructed dorsal roots following afferent electrical stimulation of the transected pelvic or pudendsal nerves.