V1583: Microsurgical Denervation of Rat Spermatic Cord: Safety and Efficacy Data

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Introduction and Objectives
Chronic orchialgia is a common urologic complaint, however, there is no established treatment for patients who have failed medical management. Spermatic cord denervation has been proposed, but intraoperative identification of all nerves is difficult and associated with a risk of injury to the deferential artery or vas deferens. The objectives of this study were to: 1) describe a microsurgical technique for denervation of the spermatic cord, 2) use a multiphoton microscopy (MPM) laser to identify and ablate residual nerves after microsurgical denervation and, 3) evaluate structural and functional changes in the rat testis and vas deferens following denervation.

Methods
Nine Sprague-Dawley rats were divided into 3 experimental groups. In the sham rats, we performed solely a midline laparotomy and mobilization of the testis. In the denervation alone group, we performed microsurgical denervation of a 5mm segment of spermatic cord. In the denervation plus MPM group, we used the MPM laser to image and ablate intact nerves immediately following microsurgical denervation. Two months after surgery, we assessed testicular volume, patency of the testicular artery with Doppler, patency of the vas deferens, and structural changes to testis and vas deferens with histology. A Kruskal-Wallis test was performed to characterize differences among groups.

Results
Median pre-surgical testicular volume was 2.9 cm3 (IQR 2.8-3.3), spermatic cord diameter was 6 mm (IQR 5-6), and vas deferens diameter was 3 mm (IQR 2.5-3). A pre and post-procedure testicular artery pulse was confirmed by Doppler in all rats. In the 3 rats that underwent MPM immediately following denervation, 2 additional nerves in each rat were identified and could be ablated with MPM. On post-surgical evaluation, there was no difference in testicular volume among the 3 experimental groups (p=0.83). A Doppler pulse was present bilaterally in all rats. In one sham and one denervation alone rat, motile sperm were absent in vasal fluid unilaterally. Vasograms were preformed with methylene blue dye in these rats and demonstrated patency. Histologically, there was no difference in testicular architecture or vasal patency among the groups.

Conclusions
A microsurgical approach can be used to effectively denervate the rat spermatic cord with minimal changes to structure and function of testis and vas deferens. Multiphoton microscopy can be used as an adjunct to identify and ablate residual nerves following microsurgical denervation.

Funding: none