Electroneuromyographic examination of pelvic floor muscle dysfunction in patients with descending perineum syndrome

Aim: to assess the functional state of the pelvic floor muscles and their innervation in patients with descending perineum syndrome, manifested simultaneously by obstructive defecation and chronic neurogenic pelvic pain. Materials and methods: in 2022–2023, 51 patients (40 (78.4 %) women, 11 (21.6 %) men; age 50.9 ± 14.5 years) with pelvic organ prolapse, manifested by obstructive defecation and chronic neurogenic pelvic pain were examined at the Ryzhikh National Medical Research Centre for Coloproctology. All patients underwent high-resolution anorectal manometry and stimulation electroneuromyography according to a comprehensive neurophysiological protocol using a St. Mark’s electrode. Results: manometric patterns of functional defecation disorders were detected in 40 (78.4 %) patients, in the rest they were confirmed by defecography data and a negative evacuation test according to the Rome criteria IV. With stimulation electroneuromyography, neuropathy was detected in 68.6 % of cases by increasing the latency of the M-response of the pudendal nerve on the right or left. Complex neurophysiological diagnostics made it possible to additionally identify neuropathy in another 25.5 % of patients: according to changes in the mixed reciprocating reflex response (mixed feedback-reflex response) (efferent pathway) — in 17.7 % of cases; according to changes in the bulbocavernous reflex (efferent and afferent pathways) — in 7.8 % of cases. That is, neuropathy was determined in 94.1 % of patients in total. Conclusions: Functional diagnostic methods are an effective tool for studying the state of the pelvic floor muscle structures and their innervation and make it possible to identify pathogenetic links of disorders, the clinical manifestations of which are anal incontinence, neurogenic pelvic pain and proctogenic constipation in the form of obstructive defecation. Stimulation electroneuromyography makes it possible to detect disturbed innervation of the pelvic floor muscles and anal sphincter in the standard study of the M-response in 68.6 % of cases with perineal prolapse syndrome with a combination of proctogenic disorders and neurogenic pelvic pain. The use of a comprehensive neurophysiological protocol makes it possible to detect innervation disorders in 94.1 % of cases.