Bilateral Posterior Tibial Nerve Stimulation in the Treatment of Rectal Evacuation Disorder: A Preliminary Report

Neuromodulation and Functional Gastrointestinal Disease

INTRODUCTION

Functional gastrointestinal disorders (FGIDs) are common, and they severely impair an individual's quality of life. The mechanism of pathogenesis and the effective treatments for FGIDs remain elusive. Neuromodulation-a relatively new treatment-has exhibited a good therapeutic effect on FGIDs, although there are different methods for different symptoms of FGIDs.

MATERIALS AND METHODS

We used PubMed to review the history of neuromodulation for the treatment of FGIDs and to review several recently proposed neuromodulation approaches with improved effects on FGIDs.

CONCLUSION

Electroacupuncture, transcutaneous electroacupuncture, transcutaneous auricular vagal nerve stimulation, sacral nerve stimulation (SNS) (which relies on vagal nerve stimulation), and gastric electrical stimulation (which works through the modulation of slow waves generated by the interstitial cells of Cajal), in addition to the noninvasive neurostimulation alternative approach method of SNS-tibial nerve stimulation and transcutaneous electrical stimulation (which is still in its infancy), are some of the proposed neuromodulation approaches with improved effects on FGIDs. This review has discussed some critical issues related to the selection of stimulation parameters and the underlying mechanism and attempts to outline future research directions backed by the existing literature.

Prevalence of Obstructed Defecation among Patients Who Underwent Hemorrhoidectomy and Correlation between Preoperative Constipation Score and Postoperative Patients' Satisfaction: A Prospective Study in Two Centers

BACKGROUND AND OBJECTIVES

obstructed defecation syndrome (ODS) is a common but underestimated condition that may affect the outcomes after hemorrhoidectomy. Therefore, the aim of this study was to determine the prevalence of obstructed defecation syndrome (ODS) among patients who underwent hemorrhoidectomy and to assess the correlation between preoperative constipation score and postoperative patients' satisfaction.

MATERIALS AND METHODS

This prospective study included adult patients who underwent hemorrhoidectomy for 3rd and 4th-grade hemorrhoidal diseases. All participant patients underwent an assessment of functional OD severity by the Agachan-Wexner Constipation Scoring System. All patients were subjected to conventional hemorrhoidectomy. At 6 months postoperatively, patients were assessed again for their constipation score and postoperative patients' satisfaction.

RESULTS

The study included 120 patients (62 males and 58 females) with a mean age of 38.7 ± 12.1 years. About one-quarter of patients (24.2%) had obstructed defecation (constipation score ≥12). ODS (constipation score ≥12) was found to be significantly more among older patients, female patients, especially those with multiple pregnancies and multiple labors, and those with perineal descent. The postoperative constipation score (5.6 ± 3.3 mean ± SD) showed significant improvement (p = 0.001) compared to (9.3 ± 3.9 mean ± SD) preoperatively. Postoperative patients' satisfaction (mean 12.3 ± 3.0) at 6 months had a negative correlation with preoperative total constipation score (r = -0.035, p = 0.702).

CONCLUSIONS

The prevalence of obstructed defecation among patients with hemorrhoids was higher than reported among the general population. High preoperative constipation scores had a negative correlation with postoperative patients' satisfaction. Routine preoperative measurement of ODS can allow the detection of this particular group of patients who require a more physical and psychological evaluation, in addition to special preoperative counseling.

Biofeedback pelvic floor muscle training versus posterior tibial nerve electrostimulation in treatment of functional obstructed defecation: a prospective randomized clinical trial

Background

Functional obstructed defecation is a common anorectal problem among adult population. The objective was to compare the short-term efficacy of biofeedback pelvic floor muscle training versus transcutaneous posterior tibial nerve electrostimulation in treatment of patients with functional obstructed defecation.

Results

There were 41 patients completed the study. There were no statistical significant differences between biofeedback pelvic floor muscle training group and transcutaneous posterior tibial nerve electrostimulation group regarding different clinical characteristics, as well as, electrophysiological findings. There was statistically significant reduction in all outcome measures after intervention in both groups. The primary outcome measure was Modified obstructed defecation score. Secondary outcome measures were Patient Assessment of Constipation-Quality of Life questionnaire, time of toileting, and maximum anal pressure during straining to evacuate. No significant differences were present between both groups regarding different outcome measures in the pretreatment and post-treatment assessments. Successful outcome was reported in 81% of patients in biofeedback pelvic floor muscle training group in comparison to 40% of patients in the posterior tibial nerve electrostimulation group according to the Modified obstructed defecation score which was the primary outcome measure.

Conclusions

Both biofeedback pelvic floor muscle training and posterior tibial nerve electrostimulation are considered effective methods in the treatment of functional obstructed defecation. However, biofeedback pelvic floor muscle training seems to be more effective and superior in comparison to posterior tibial nerve electrostimulation. Posterior tibial nerve electrostimulation could be combined with biofeedback pelvic floor muscle training or considered as a second line therapy after failure of biofeedback pelvic floor muscle training.

Trial registration

Pan African Clinical Trials Registry, PACTR202009762113535. Registered 2 September 2020—retrospectively registered, https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=12321.

Transcutaneous Electrical Acustimulation Improves Constipation by Enhancing Rectal Sensation in Patients With Functional Constipation and Lack of Rectal Sensation

INTRODUCTION

Reduced rectal sensation is involved in the pathophysiology of constipation. The aim of this study was to investigate the effects of transcutaneous electrical acustimulation (TEA) at acupuncture point ST36 on constipation and rectal sensation as well as autonomic functions in patients with constipation and reduced rectal sensation.

METHODS

In an acute study, anorectal motility and sensation tests were performed in constipation patients (N = 53) who were treated with TEA at ST36 or sham points. In a chronic study, patients (N = 18) underwent 2 weeks of TEA or sham-TEA in a crossover design.

RESULTS

Chronic TEA increased spontaneous bowel movements (3.72 vs 2.00 per week with sham-TEA, P < 0.0001) and significantly reduced constipation symptoms and increased quality of life in comparison with sham-TEA (P < 0.05). Acute TEA reduced the sensation threshold in response to rectal distention for the urge of defecation and maximum tolerable volume (P < 0.05, vs baseline); chronic TEA reduced the sensation thresholds for first sensation and desire of defecation, and decreased the threshold volume to an elicit rectal anal inhibitory reflex (P < 0.05). Both acute and chronic TEA increased parasympathetic activity (P < 0.05).

DISCUSSION

TEA at ST36 improves chronic constipation by enhancing rectal sensation possibly mediated by the reinforcement of parasympathetic activity in patients with functional constipation and reported lack/absence of rectal sensation.

Relation between pelvic floor neurophysiological abnormalities and erectile dysfunction in patients with obstructed defecation

Background

Obstructed defecation is a common pelvic floor medical problem among adult population. Pelvic floor disorders were reported to be associated with sexual dysfunction including erectile dysfunction among male patients. The aim was to determine the relation between pelvic floor neurophysiological abnormalities and erectile dysfunction in male patients with obstructed defecation.

Methods

This cross-sectional study included 65 married male patients with obstructed defecation and a control group consisted of 15 apparently healthy married males. Assessment of obstructed defecation severity was done by using modified obstructed defecation score, time of toileting and Patient Assessment of Constipation-Quality of Life questionnaire. Assessment of erectile functions was done using erectile function domain of International Index of Erectile Function questionnaire and Erectile Dysfunction-Effect on Quality of Life Questionnaire. Anal manometry and dynamic pelvis magnetic resonance imaging were done. Electrophysiological studies included pudendal nerve motor conduction study and needle electromyography of external anal sphincter, puborectalis and bulbocavernosus muscles.

Results

There were 32 patients (49.2%) who had erectile dysfunction. The maximum straining anal pressure was significantly higher among patients with erectile dysfunction. Pudendal nerve terminal motor latency was significantly delayed and the percentage of bilateral pudendal neuropathy was significantly higher among patients with erectile dysfunction. The percentage of electromyography evidence of denervation with chronic reinnervation in the external anal sphincter and bulbocavernosus muscles were significantly higher among patients with erectile dysfunction. Regression analysis detected three co-variables to be associated with significantly increasing the likelihood of development of erectile dysfunction. These were maximum straining anal pressure (odd ratio = 1.122), right pudendal nerve terminal motor latency (odd ratio = 3.755) and left pudendal nerve terminal motor latency (odd ratio = 3.770).

Conclusions

Erectile dysfunction is prevalent among patients with obstructed defecation. It is associated with characteristic pelvic floor electrophysiological abnormalities. Pelvic floor neurophysiological changes vary from minimal to severe neuromuscular abnormalities that usually accompanying erectile dysfunction. Pudendal neuropathy and increased maximum straining anal pressure are essential risk factors for increasing the likelihood of development of erectile dysfunction in patients with obstructed defecation.

The role of neuromodulation in chronic functional constipation: a systematic review

BACKGROUND

Chronic functional constipation is a highly prevalent disorder in which, when conservative measures fail to relieve symptoms, surgical interventions are sometimes indicated. In recent years, neuromodulation for the treatment of functional constipation has gained interest but its role and effectiveness are still unclear. The purpose of this review is to provide a systematic overview on the current literature on the different modalities of neurostimulation and their effect on chronic functional constipation in adults as reported in the literature.

METHODS

A search in the literature for articles concerning the effect of different types of neuromodulation on constipation was performed in PubMed using extensive search terms for the different modalities of neuromodulation. Studies and trials were checked for eligibility. For all types of neuromodulation together, 27 articles were included.

RESULTS

17 studies were included on SNM (sacral nerve modulation). Although multiple studies show positive results on the effect of SNM in constipation, double-blind crossover RCT's (randomised controlled trials) showed no significant effect. 3 studies were included for tSNS (transcutaneous sacral nerve stimulation), 2 for PTNS (percutaneous tibial nerve stimulation) and 2 for TTNS (transcutaneous tibial nerve stimulation). Studies and trials on these modalities of neuromodulation reported ambiguous results on statistical significance of the effect. For transcutaneous IFC (interferential current therapy) 2 studies were included, which both reported a statistically significant effect on all outcomes.

CONCLUSION

The beneficial effect of neuromodulation in chronic functional constipation remains questionable. However, neuro-modulation might be worth considering in patients refractory to treatment before turning to more invasive measures. Future research should shed more light on the effects of neuromodulation in constipation.

MAIN MANOMETRIC FINDINGS AND POTENTIAL FOR ANORECTAL PHYSICAL THERAPY IN THE TREATMENT OF PATIENTS WITH EVACUATION DISORDERS

BACKGROUND

Evacuation disorders are prevalent in the adult population, and a significant portion of cases may originate from pelvic floor muscle dysfunctions. Anorectal manometry (ARM) is an important diagnostic tool and can guide conservative treatment.

OBJECTIVE

To evaluate the prevalence of pelvic dysfunction in patients with evacuation disorders through clinical and manometric findings and to evaluate, using the same findings, whether there are published protocols that could be guided by anorectal manometry.

METHODS

A retrospective analysis of a prospective database of 278 anorectal manometries performed for the investigation of evacuation disorders in patients seen at the anorectal physiology outpatient clinic of Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto between January 2015 to June 2019 was conducted. The following parameters were calculated: resting pressure (RP), squeeze pressure (SP), high-pressure zone (HPZ), rectal sensitivity (RS) and rectal capacity (RC). The pressure measurements and manometric plots were reviewed to determine the diagnosis and to propose potential pelvic physical therapy procedures. Analysis of variance (ANOVA) and Fisher's exact test were used to compare the continuous variables and to evaluate the equality of variances between groups of patients with fecal incontinence (FI) and chronic constipation (CC). Results with a significance level lower than 0.05 (P-value <0.05) were considered statistically significant. Statistical analysis was performed using IBM® SPSS® Statistics version 20.

RESULTS

The mean age of the sample was 45±22 years, with a predominance of females (64.4%) and economically inactive (72.7%) patients. The indications for exam performance were FI (65.8%) and CC (34.2%). Patients with FI had lower RP (41.9 mmHg x 67.6 mmHg; P<0.001), SP (85.4 mmHg x 116.0 mmHg; P<0.001), HPZ (1.49 cm x 2.42 cm; P<0.001), RS (57.9 mL x 71.5 mL; P=0.044) and RC (146.2 mL x 195.5 mL; P<0.001) compared to those of patients with CC. For patients with FI, the main diagnosis was the absence of a functional anal canal (49.7%). For patients with CC, the main diagnosis was outflow tract obstruction (54.7%). For patients with FI, the main protocol involved a combination of anorectal biofeedback (aBF) with tibial nerve stimulation (TNS) (57.9%). For patients with CC, the most indicated protocol was aBF combined with TNS and rectal balloon training (RBT) (54.7%).

CONCLUSION

There was a high prevalence of pelvic floor changes in patients with evacuation disorders. There was a high potential for performing pelvic floor physical therapy based on the clinical and manometric findings.

Transcutaneous Neuromodulation at ST36 (Zusanli) is More Effective than Transcutaneous Tibial Nerve Stimulation in Treating Constipation

BACKGROUND AND GOALS

Combined transcutaneous neuromodulation (TN) at acupoint ST36 (Zusanli) and TN at the posterior tibial nerve (PTN) has been reported effective in treating functional constipation. This study was designed to compare the effectiveness of TN between these 2 points.

MATERIALS AND METHODS

Eighteen functional constipation patients (M/F: 9/9) were recruited to participate in a cross-over study with a 2-week TN at ST36 and a 2-week TN at PTN. A bowel movement diary, and the questionnaires of Patient Assessment of Constipation Symptom (PAC-SYM) and Constipation Quality of Life (PAC-QoL) were completed; anorectal manometry and spectral analysis of heart rate variability for assessing the autonomic function were performed.

RESULTS

(1) Both TN at ST36 and TN at PTN improved constipation-related symptoms (PAC-SYM scores on pre-TN vs. post-TN: 1.4±0.1 vs. 0.6±0.1 for ST36, 1.4±0.1 vs. 0.9±0.1 for PTN, both P≤0.001). (2) TN at ST36, but not TN at PTN, increased the number of weekly spontaneous bowel movements (0.9±0.2 pre-TN vs. 3.5±0.7 post-TN, P<0.001) and decreased the total PAC-QoL score. TN at ST36 was more potent than TN at PTN in improving the PAC-SYM score (decrement 0.8±0.1 vs. 0.5±0.1, P<0.05). (3) TN at ST36 rather than TN at PTN resulted in a reduction in sensation thresholds, including rectal distention for urge (134.1±14.3 mL pre-TN vs. 85.6±6.5 mL post-TN, P<0.01) and maximum tolerance (P<0.05). (4) Both TN at ST36 and TN at PTN significantly increased vagal activity and decreased sympathetic activity (P<0.05).

CONCLUSIONS

TN at ST36 is more potent than TN at PTN in treating constipation and improving constipation-related symptoms and rectal sensation.

Management of functional constipation in children and adults

Functional constipation is common in children and adults worldwide. Functional constipation shows similarities in children and adults, but important differences also exist regarding epidemiology, symptomatology, pathophysiology, diagnostic workup and therapeutic management. In children, the approach focuses on the behavioural nature of the disorder and the initial therapeutic steps involve toilet training and laxatives. In adults, management focuses on excluding an underlying cause and differentiating between different subtypes of functional constipation - normal transit, slow transit or an evacuation disorder - which has important therapeutic consequences. Treatment of adult functional constipation involves lifestyle interventions, pelvic floor interventions (in the presence of a rectal evacuation disorder) and pharmacological therapy. When conventional treatments fail, children and adults are considered to have intractable functional constipation, a troublesome and distressing condition. Intractable constipation is managed with a stepwise approach and in rare cases requires surgical interventions such as antegrade continence enemas in children or colectomy procedures for adults. New drugs, including prokinetic and prosecretory agents, and surgical strategies, such as sacral nerve stimulation, have the potential to improve the management of children and adults with intractable functional constipation.