Changes in the Urethral Artery After Experimental Subarachnoid Hemorrhage-Induced Injury of the Pudendal Ganglion and Onuf's Nucleus Junction.

Objective: Onuf's nucleus is an anatomical structure essential in the regulation of urogenital functions. Lumbosacral pathologies may cause changes in urogenital circulation due to Onuf's nucleus injury; however, there is limited evidence corroborating the relationship between spinal cord injury and urethral artery changes.

Materials and methods: We used 23 sexually mature male rabbits-5 rabbits in the control group (GI), 5 rabbits in the sham group (GII), and 13 rabbits in the experimental group (GIII; received autologous blood transfusion into the T12-L1 subarachnoid space to induce subarachnoid hemorrhage (SAH). The GIII underwent a S1-3 laminectomy after 2 weeks and was decapitated. Histologic specimens were prepared to examine changes in Onuf's nucleus, pudendal ganglion, and urethral arteries. The density of damaged neurons and vasospasm index (VSI) in the urethral artery were evaluated.

Results: The mean density of damaged neurons (n/mm3 ) in Onuf's nucleus and pudendal ganglia (S3) and the mean VSI of the 3 groups were as follows-GI: 6 ± 2 per mm3 , 12 ± 4 per mm3 , and 1.63 ± 0.25, respectively; GII: 27 ± 6 per mm3 , 221 ± 62 per mm3 , and 1.97 ± 0.36, respectively; GIII: 154 ± 41 per mm3 , 1890 ± 541 per mm3 , and 3.04 ± 0.95 (P < .05 each for GI/GII, GI/GIII, and GII/GIII). Neuronal damage criteria, such as cytoplasmic condensation and cytoplasmic halo formation, were more prominent in GIII.

Conclusion: SAH can lead to ischemia of the Onuf's nucleus-pudendal nerve structures due to urethral artery spasm, resulting in urogenital complications.