Compound muscle action potential of the external anal sphincter

Kegel Exercises, Biofeedback, Electrostimulation, and Peripheral Neuromodulation Improve Clinical Symptoms of Fecal Incontinence and Affect Specific Physiological Targets: An Randomized Controlled Trial

Background/Aims

Fecal incontinence (FI) is a prevalent condition among community-dwelling women, and has a major impact on quality of life (QoL). Research on treatments commonly used in clinical practice—Kegel exercises, biofeedback, electrostimulation, and transcutaneous neuromodulation—give discordant results and some lack methodological rigor, making scientific evidence weak. The aim is to assess the clinical efficacy of these 4 treatments on community-dwelling women with FI and their impact on severity, QoL and anorectal physiology.

Methods

A randomized controlled trial was conducted on 150 females with FI assessed with anorectal manometry and endoanal ultrasonography, and pudendal nerve terminal motor latency, anal/rectal sensory-evoked-potentials, clinical severity, and QoL were determined. Patients were randomly assigned to one of the following groups Kegel (control), biofeedback + Kegel, electrostimulation + Kegel, and neuromodulation + Kegel, treated for 3 months and re-evaluated, then followed up after 6 months.

Results

Mean age was 61.09 ± 12.17. Severity of FI and QoL was significantly improved in a similar way after all treatments. The effect on physiology was treatment-specific Kegel and electrostimulation + Kegel, increased resting pressure (P < 0.05). Squeeze pressures strongly augmented with biofeedback + Kegel, electrostimulation + Kegel and neuromodulation + Kegel (P < 0.01). Endurance of squeeze increased in biofeedback + Kegel and electrostimulation + Kegel (P < 0.01). Rectal perception threshold was reduced in the biofeedback + Kegel, electrostimulation + Kegel, and neuromodulation + Kegel (P < 0.05); anal sensory-evoked-potentials latency shortened in patients with electrostimulation + Kegel (P < 0.05).

Conclusions

The treatments for FI assessed have a strong and similar efficacy on severity and QoL but affect specific pathophysiological mechanisms. This therapeutic specificity can help to develop more efficient multimodal algorithm treatments for FI based on pathophysiological phenotypes.

Defective Conduction of Anorectal Afferents Is a Very Prevalent Pathophysiological Factor Associated to Fecal Incontinence in Women

Background/Aims

Fecal incontinence (FI) is a prevalent condition among women. While biomechanical motor components have been thoroughly researched, anorectal sensory aspects are less known. We studied the pathophysiology of FI in community-dwelling women, specifically, the conduction through efferent/afferent neural pathways.

Methods

A cross-sectional study was conducted on 175 women with FI and 19 healthy volunteers. The functional/structural study included anorectal manometry/endoanal ultrasound. Neurophysiological studies including pudendal nerve terminal motor latency (PNTML) and sensory-evoked-potentials to anal/rectal stimulation (ASEP/RSEP) were conducted on all healthy volunteers and on 2 subgroups of 42 and 38 patients, respectively.

Results

The main conditions associated with FI were childbirth (79.00%) and coloproctological surgery (37.10%). Cleveland score was 11.39 ± 4.09. Anorectal manometry showed external anal sphincter and internal anal sphincter insufficiency in 82.85% and 44.00%, respectively. Sensitivity to rectal distension was impaired in 27.42%. Endoanal ultrasound showed tears in external anal sphincter (60.57%) and internal anal sphincter disruptions (34.80%). Abnormal anorectal sensory conduction was evidenced through ASEP and RSEP in 63.16% and 50.00% of patients, respectively, alongside reduced activation of brain cortex to anorectal stimulation. In contrast, PNTML was delayed in only 33.30%. Stools were loose/very loose in 56.70% of patients.

Conclusions

Pathophysiology of FI in women is mainly associated with mechanical sphincter dysfunctions related to either muscle damage or, to a lesser extent, impaired efferent conduction at pudendal nerves. Impaired conduction through afferent anorectal pathways is also very prevalent in women with FI and may play an important role as a pathophysiological factor and as a potential therapeutic target.