We determined whether transfer of a primarily motor nerve (femoral) to the anterior vesicle branch of the pelvic nerve would allow for more effective bladder reinnervation than transfer of a primarily sensory nerve (genitofemoral). A total of 41 female mongrel dogs underwent bladder decentralization and then bilateral nerve transfer, or served as sham operated or unoperated controls. Decentralization was achieved by bilateral transection of all sacral roots that induced bladder contraction upon electrical stimulation. Retrograde neuronal labeling dye was injected in the bladder 3 weeks before sacrifice. Increased detrusor pressure after direct stimulation of the transferred nerve, lumbar spinal cord or spinal root was observed in 12 of 17 dogs with genitofemoral nerve transfer and in 9 of 10 with femoral nerve transfer (mean ± SEM 7.6 ± 1.4 and 11.7 ± 3.1 cm H2O, respectively). Mean detrusor pressure after direct electrical stimulation of transferred femoral nerves was statistically significantly greater than after stimulation of transferred genitofemoral nerves. Retrograde labeled neurons from the bladder observed in upper lumbar cord segments after genitofemoral and femoral nerve transfer confirmed bladder reinnervation, as did labeled axons at the nerve transfer site. While transfer of a mixed sensory and motor nerve (genitofemoral) or a primarily motor nerve (femoral) can reinnervate the bladder, using the primarily motor nerve provided greater return of nerve evoked detrusor contraction. This surgical approach may be useful to achieve bladder emptying in patients with lower motor spinal cord injury.

BACKGROUND: Cervical spinal cord injuries result in a severe loss of function and independence. The primary goal for these patients is the restoration of hand function. Nerve transfers have recently become a powerful intervention to restore the ability to grasp and release objects. The supinator muscle, although a suboptimal tendon transfer donor, serves as an ideal distal nerve donor for reconstructive strategies of the hand. This transfer is also applicable to lower brachial plexus injuries. OBJECTIVE: To describe the supinator to posterior interosseous nerve transfer with the goal of restoring finger extension following spinal cord or lower brachial plexus injury. METHODS: Nerve branches to the supinator muscle are transferred to the posterior interosseous nerve supplying the finger extensor muscles in the forearm. RESULTS: The supinator to posterior interosseous nerve transfer is effective in restoring finger extension following spinal cord or lower brachial plexus injury. CONCLUSION: This procedure represents an optimal nerve transfer as the donor nerve is adjacent to the target nerve and its associated muscles. The supinator muscle is innervated by the C5-6 nerve roots and is often available in cases of cervical SCI and injuries of the lower brachial plexus. Additionally, supination function is retained by supination action of the biceps muscle.

Aims: Complete spinal cord injury does not block perceptual responses or inferior solitary nucleus activation after genital self‐stimulation, even though the vagus is not thought to innervate pelvic structures. We tested if vagus nerve endings sprout after bladder decentralization to innervate genitourinary structures in canines with decentralized bladders.Methods: Four reinnervation surgeries were performed in female hounds: bilateral genitofemoral nerve transfer to pelvic nerve with vesicostomy (GNF‐V) or without (GFN‐NV); and left femoral nerve transfer (FNT‐V and FNT‐NV). After 8 months, retrograde dyes were injected into genitourinary structures. Three weeks later, at euthanasia, reinnervation was evaluated as increased detrusor pressure induced by functional electrical stimulation (FES). Controls included un‐operated, sham‐operated, and decentralized animals.Results: Increased detrusor pressure was seen in 8/12 GFNT‐V, 4/5 GFNT‐NV, 5/5 FNT‐V, and 4/5 FNT‐NV animals after FES, but not decentralized controls. Lumbar cord segments contained cells labeled from the bladder in all nerve transfer animals with FES‐induced increased detrusor pressure. Nodose ganglia cells labeled from the bladder were observed in 5/7 nerve transfer animals (1/2 GNT‐NV; 4/5 FNT‐V), and from the clitoris were in 6/7 nerve transfer animals (2/2 GFNT‐NV; 4/5 FNT‐V). Dorsal motor nucleus vagus cells labeled from the bladder were observed in 3/5 nerve transfer animals (1/2 GFNT‐NV; 2/3 FNT‐V), and from the clitoris in 4/5 nerve transfer animals (1/2 GFNT‐NV; 3/3 FNT‐V). Controls lacked this labeling.Conclusions: Evidence of vagal nerve sprouting to the bladder and clitoris was observed in canines with lower motoneuron lesioned bladders. Neurourol. Urodynam. 36:91–97, 2017.

Lower motor neuron (LMN) damage results in denervation of the associated muscle targets and is a significant yet under-appreciated component of spinal cord injury (SCI). Denervated muscle undergoes a progressive degeneration and fibro-fatty infiltration that eventually renders the muscle non-viable unless reinnervated within a limited time window. The distal nerve deprived of axons also undergoes degeneration and fibrosis making it less receptive to axons. In this review, we describe the LMN injury associated with SCI and its clinical consequences. The process of degeneration of the muscle and nerve is broken down into the primary components of the neuromuscular circuit and reviewed, including the nerve and Schwann cells, the neuromuscular junction, and the muscle. Finally, we discuss three promising strategies to reverse denervation atrophy. These include providing surrogate axons from local sources; introducing stem cell-derived spinal motor neurons into the nerve to provide the missing axons; and finally, instituting a training program of high-energy electrical stimulation to directly rehabilitate these muscles. Successful interventions for denervation atrophy would significantly expand reconstructive options for cervical SCI and could be transformative for the predominantly LMN injuries of the conus medullaris and cauda equina.