Neurophysiology of the pelvic floor muscles. Entering clinical practice

AIM: to develop methods of conservative treatment of proctological patients based on pelvic floor muscles (PFM) neurophysiology.
PATIENTS AND METHODS: thirty-seven patients with pudendal neuropathy manifested by anal incontinence (AI) and/or obstructive defecation and/or neurogenic pelvic pain (and their combination) included in the prospective cohort study. There were 5 patients (13.5%) with proctogenic constipation as the main complaint, 12 (32.4%) with AI, 14 (37.9%) with neurogenic pelvic pain; 6 (16.2%) with combined disorders. There were 22 (59.5%) women, 15 (40.5%) men, aged 47.1 ± 15.7 years. All patients underwent a comprehensive checkup by a proctologist, colonoscopy, gynecologist/urologist. The neurophysiological tests were performed according to the developed algorithm, including stimulation EMG (PNMTL) with the late phenomena and bulbocavernosus reflex (BCR), as well as interference EMG to identify dysfunction of the PFM. Patients with obstructive defecation additionally underwent high-resolution anorectal manometry, defecography and evacuation test. Patients with AI underwent complex sphincterometry. All patients underwent conservative treatment, which depended on the obtained diagnostic data.
RESULTS: according to PNTML, pudendal neuropathy were diagnosed only by an increase in the latency of the M-response in 21 patients (56.8%). In this case, all had a unilateral change (up to 3.6 ± 1.1 ms on the right in 6/21 (28.6%) and up to 3.2 ± 0.6 ms on the left in 15/21 (71.4%). Based on the increase in the latency of late phenomena, pudendal neuropathy was detected in another 10 (27%) patients — up to 52.6 ± 9.1 ms on the right and up to 51.4 ± 7.1 ms on the left; based on the increase in the latency of the BCR in 6 (16.2%) people — up to 52.3 ± 5.4 ms on the right and up to 51.9 ± 7.3 ms on the left. All patients underwent interference EMG. EMG-signs of PFM dysfunction during the push-test were detected in 24 (64.9%) patients, which coincided with the data of high-resolution anorectal manometry (HRAM) — among them were not only patients with predominant complaints of proctogenic disorders, but also from other groups: 10 (41.6%) with obstructive defecation, 7 (29.2%) with neurogenic pelvic pain, 3 (12.5%) with AI, 4 (16.7%) — with mixed manifestations. Signs of AI according to sphincterometry data were detected in 20/22 women (resting pressure 34.4 ± 4.0 mmHg, squeezing pressure 99.4 ± 22.0 mmHg) and in 11/15 men (37.7 ± 2.4 mmHg and 122.0 ± 39.0 mmHg). The clinical output of the algorithm we created was the development of a biofeedback (BFB) technique on a myographic complex of diagnostic profile with high-intensity magnetic stimulation (HIMS).
CONCLUSION: patients with pudendal neuropathy may have concomitant dysfunctions in the form of AI, obstructive defecation and neurogenic pelvic pain. Given the dominant nature of the pain syndrome, obstructive defecation and anal incontinence are undiagnosed conditions and, in some cases, have a latent manifestation, which requires targeted questioning of patients and additional examination, including PNTML, interference EMG, HRAM, complex sphincterometry, defecography. The use of biofeedback on a diagnostic myographic complex in combination with HIMS allows for adequate training of patients in the synergistic work of the PFM and the abdominal muscles for proper defecation/urination and faeces/urine retention.

1. Bianchi F, Squintani GM, Osio M, et al. Neurophysiology of the pelvic floor in clinical practice: a systematic literature review. Funct Neurol. 2017;22(4):173–193. doi: 10.11138/fneur/2017.32.4.173

2. Peng Y, Miller BD, Boone TB, et al. Modern Theories of Pelvic Floor Support : A Topical Review of Modern Studies on Structural and Functional Pelvic Floor Support from Medical Imaging, Computational Modeling, and Electromyographic Perspectives. Curr Urol Rep. 2018;19(1):9. doi: 10.1007/s11934-018-0752-9

3. Khatri G, Khan A, Raval G, et al. Diagnostic Evaluation of Chronic Pelvic Pain. Phys Med Rehabil Clin N Am. 2017 Aug;28(3):477–500. doi: 10.1016/j.pmr.2017.03.004

4. Corvino F, Giurazza F, Coppola M. Chronic Pelvic Pain in Congestion Pelvic Syndrome: Clinical Impact and Electromyography Pelvic Floor Activity Prior to and after Endovascular Treatment. J Pers Med. 2024;14(6):661. doi: 10.3390/jpm14060661

5. Shelygin Yu.A., Fomenko O.Yu., Titov A.Yu., et al. Method for assessing the functional state of the rectal locking device. Patent № 2576445 RU dated 11.03.2015. (in Russ.).

6. Shelygin Yu.A., Fomenko O.Yu., Nikolaev S.G., et al. Method for determining the neurophysiological state of the pelvic floor muscles. Patent № 2708052 RU dated 09.17.2019. (in Russ.).

7. Shelygin Yu.A., Fomenko O.Yu., Nikolaev S.G., et al. Method of neurophysiological examination of the pelvic floor muscles and the locking apparatus of the rectum. Patent N 2741725 RU dated 06.18.2020. (in Russ.).

8. Fomenko O.Yu., Martynov M.U., Dreval O.N., et al. Stimulating electroneuromyography in the diagnosis of neurogenic disorders of the pelvic floor muscles. S.S. Korsakov Journal of Neurology and Psychiatry. 2021;121(4):48–56. (In Russ.) doi: 10.17116/jnevro202112104148

9. Fomenko O.Y. The role of electromyography in the diagnosis of anal incontinence. Dissertation ... Ph.D.M.M.; 2007.

10. Fomenko O.Yu., Morozov S.V., Kashnikov V.N., et al. Electroneuromyographic examination of pelvic floor muscle dysfunction in patients with descending perineum syndrome. Medical alphabet. 2024;(15):44–50. (In Russ.). doi: 10.33667/2078-5631-2024-15-44-50

11. Lacy BE, Mearin F, Chang L, et al. Bowel Disorders. Gastroenterology. 2016;150:1393–1407. doi: 10.1053/j.gastro.2016.02.031

12. Rao SS, Bharucha AE, Chiarioni G, et al. Anorectal Disorders. Gastroenterology. 2016;150(6):1430–1442.e4. doi: 10.1053/j.gastro.2016.02

13. Fomenko O.Yu., Shelygin Yu.A., Shkoda A.S., et al. Method for correcting disorders of the functional state of the anal sphincter and pelvic floor muscles in patients with anal incontinence. Patent № 2753580 RU dated January 28, 2021. (In Russ.).

14. Fomenko O.Yu., Shelygin Yu.A., Achkasov S.I., et al. Method of treatment of neurogenic chronic pelvic pain. Patent № 2766778 RU dated 11.11.2021. (In Russ.).

15. Fomenko O.Yu., Shelygin Yu.A., Achkasov S.I., et al. Method of treatment of obstructive bowel movements using biofeedback. Patent N 2771420 RU dated 12.21.2021. (In Russ.).

16. Fomenko O.Yu., Shelygin Yu.A., Skoda A.S., et al. Method of correction of functional disorders muscles of the anal sphincter and pelvic floor in patients with pelvic organ prolapse in combination with obstructive bowel movements and the presence or absence of anal incontinence. Patent N 2752370 RU dated 28.01.2021. (In Russ.).