VARIANT ANATOMY AND TOPOGRAPHY OF THE PUDENDAL NERVE IN ADULT MEN ACCORDING TO MAGNETIC RESONANCE IMAGING

The objective of this study was to study the variant anatomy and topography of the pudendal nerve in mature men according to magnetic resonance imaging (MRI).

Material and methods. The present study included 140 patients aged 21 to 59 years of first and second periods of adulthood. The inclusion criteria for patients in the study were: the absence of active complaints from the genitourinary system and pathological processes in the pelvic cavity according to the MRI study. MRIs of the small pelvis for analyzing the variant anatomy and topography of the pudendal nerve were obtained using Siemens Magnetom Essenza 1.5 T (Siemens, Germany) and Phillips Achieva 1.5 T (Phillips, the Netherlands) MRI devices in three planes without the administration of a contrast agent.

Results. The study of the nature of the pudendal nerve branching and the types of relationship of the pudendal nerve and its branches to the sacrospinous ligament showed the following results: the most common type was type I (single-barreled nature of the branching of the nerve; the pudendal nerve passes under the sacrospinous ligament), which was detected in 79 (56, 4%) patients, the least common was type V (three-barreled nature of the branching of the nerve; the pudendal nerve passes under the sacrospinous ligament), identified in 12 (8.5%) respondents. The sources of formation of the pudendal nerve in 72 (51.5%) cases were the roots of S2, S3 and S4, in 59 (42.1%) patients the pudendal nerve was formed from S2 and S4 roots, and in 9 (6.4%) cases the pudendal nerve originated from S3 and S4 roots. When comparing the average values of the diameters of the main trunks of the pudendal nerve of the patients of the first and second periods of adulthood, we noted significant differences (4.65±1.15 mm and 3.88±0.94 mm, respectively, p=0.029). The comparison of the average lengths of the pudendal nerve trunks of patients of the first and second periods of adulthood showed no significant differences (p=1.0). With pronounced filling of the rectum and the bladder, there is a maximum «pressing» of the main trunk of the pudendal nerve to the obturator internus muscle and ischial spine.

Conclusion. An MRI study of the pelvic organs in mature men with T2-weighted images data allows a detailed study of the variant anatomy and topography of the pudendal nerve from the origins of its formation to division into terminal branches. This imaging method is distinguished by the highest intertissue contrast, high spatial resolution and the ability to obtain sections in any plane.

1. Sergienko V. I., Petrosyan E. A. Topograficheskaya anatomiya i operativnaya hirurgiya (Topographic anatomy and operative surgery): uchebnik. Moskva: GEOTAR-Media, 2013: 648. (in Russ)

2. Izvozchikov S. B. Mechanisms of formation and diagnosis of tunnel pudendal neuropathy. S.S. Korsakov Journal Of Neurology And Psychiatry. 2019;119(11):98-102. doi: 10.17116/jnevro201911911198 (in Engl)

3. Khoder W., Hale D.Pudendal neuralgia. Obstet Gynecol Clin North Am. 2014;41(3):443-452. doi: 10.1016/j.ogc.2014.04.002 (in Engl)

4. Levesque A., Bautrant E., Quistrebert V. [et al.] Levesque, A. Recommendations on the management of pudendal nerve entrapment syndrome: A formalised expert consensus. Eur J Pain. 2022; 26(1):7-17. doi: 10.1002/ejp.1861 (in Engl)

5. Wadhwa V., Hamid A. S., Kumar Y. [et al.] Pudendal nerve and branch neuropathy: magnetic resonance neurography evaluation. Acta Radiol. 2017; 58(6):726-733. doi: 10.1177/0284185116668213 (in Engl)

6. Weissman, E. Boothe E, Wadhwa V, Scott K, Chhabra A. Magnetic Resonance Neurography of the Pelvic Nerves. Semin Ultrasound CT MR. 2017;N 3: 269-278. doi: 10.1053/j.sult.2016.11.006 (in Engl)

7. Aggarwal A., Srivastava D. N., Jana M. M. [et al.] Comparison of Different Sequences of Magnetic Resonance Imaging and Ultrasonography with Nerve Conduction Studies in Peripheral Neuropathies. World Neurosurg. 2017;108:185-200. doi: 10.1016/j.wneu.2017.08.054 (in Engl)

8. Mahakkanukrauh P., Surin P., Vaidhayakarn P. Anatomical study of the pudendal nerve adjacent to the sacrospinous ligament. Clin Anat. 2005; 18(3):200-205. doi: 10.1002/ca.20084 (in Engl)

9. World Medical Association. World Medical Association Declaration of Helsinki: ethical principles for medical research involving human subjects. JAMA. 2013; 310(20):2191-2194. doi: 10.1001/jama.2013.281053

10. Montoya T. I., Calver L., Carrick K. S. [et al.] Anatomic relationships of the pudendal nerve branches. Am J Obstet Gynecol. 2011; 205(5):504.e1-504.e5045. doi: 10.1016/j.ajog.2011.07.014