Abstract

Background:
The pudendal nerve (PDN) plays a crucial role in external urethral sphincter (EUS) innervation, contributing to urinary control and coordinating the action of the bladder with the EUS.

Aim:
This study aimed to assess the therapeutic potential of omental pedicle transposition in treating neuropathic stress urinary incontinence induced by complete transection of the motor branch of the PDN (MBPDN).

Methods:
Forty healthy adult female New Zealand White rabbits were randomly divided into four groups (n = 10). In group A, the MBPDN was completely transected and left untreated. The transected MBPDN was repaired in group B through direct end-to-end coaptation. Group C underwent end-to-end nerve coaptation after neurotmesis, followed by wrapping the coaptation site with an omental pedicle transposition. Group D served as the normal control without nerve injury and was included only for comparative statistical analysis.

Results:
Cystometric measurements were performed at weeks 4 and 16 to evaluate detrusor pressure (P_det), bladder compliance (BC), and leak point pressure (LPP). These parameters were used to assess bladder dynamics. Surface electromyography of the external urethral sphincter (EUS) was also recorded at the same time points (4th and 16th weeks) to measure the EUS amplitude and assess its neuromuscular integrity. Cytometric analysis revealed a highly significant treatment effect (p < 0.001). Compared with the normal control group (D), group A showed the most severe EUS dysfunction, characterized by increased P_det, minimal BC, and the lowest LPP, indicating persistent detrusor overactivity and poor detrusor-sphincter coordination following untreated MBPDN injury. Group B demonstrated moderate improvement after end-to-end nerve coaptation, indicating partial recovery. By contrast, group C showed the greatest degree of functional recovery, with bladder function parameters approaching those of the normal control group D by week 16. The P_det progressively decreased, whereas BC and LPP increased to near-normal values, indicating almost complete restoration of detrusor stability and sphincteric control.

Conclusion:
In conclusion, these findings indicate that omental pedicle transposition enhances transected MBPDN regeneration and functional recovery of the EUS, leading to near-normal bladder function restoration compared with direct end-to-end nerve coaptation alone.

Key words: Neuropathic stress urinary incontinence; Motor branch of pudendal nerve; Omental pedicle transposition; Nerve regeneration; Surface electromyography.