Nerve Transfer Strategies for Restoring Bladder, Bowel, Genital, and Lower Extremity Functions in Spinal Cord Injury: A Systematic Review.

Background: Nerve transfers have been proposed solutions for urinary, bowel, and genital dysfunction after spinal cord injury (SCI). However, there remains a need to characterize nerve candidates and other treatment variables for SCI. The objective of this systematic review was to characterize nerve transfer strategies and outcomes for the restoration of bladder, bowel, genital, and lower extremity function after SCI.

Methods: PubMed, Cochrane, MEDLINE, and Embase libraries were queried according to the preferred reporting items for systematic reviews and meta-analyses guidelines for articles that presented outcomes after SCI in humans, animals, and cadavers treated with nerve transfer.

Results: Thirty-one studies with 471 subjects were included. Thirteen studies were anatomical feasibility, 11 were animal, and 7 were clinical studies. The sacral (n = 218) and pudendal (n = 100) nerves were injured the most. There were 490 nerve transfers, with genitofemoral (n = 113) and femoral (n = 88) nerves transferred the most. Satisfactory bladder void control was regained in 75% of sacral, 100% of intercostal, and 88% of lumbar nerve transfer patients. Spontaneous void of bowel was regained in 78% of lumbar nerve transfer patients. Two patients with lumbosacral plexus nerve root injuries had improved knee extension from grade 0/5 to 2/5 and 3/5 after obturator nerve transfer.

Conclusions: This review demonstrates feasibility of transferring genitofemoral, femoral, sacral, and ilioinguinal nerves for the restoration of bladder, bowel, genital, and lower extremity function. While these studies suggest potential nerve transfer options, only 7 studies examined the outcomes in humans. Both the feasibility and applicability of nerve transfer after SCI must be explored further in clinical research.