Clinical utility of trans-sacral magnetic stimulation-evoked sphincter potentials and high-density electromyography in pelvic floor assessment: Technical evaluation.

AIM: Faecal incontinence is common and of multifactorial aetiologies, yet current diagnostic tools are unable to assess nerve and sphincter function objectively. We developed an anorectal high-density electromyography (HD-EMG) probe to evaluate motor-evoked potentials induced via trans-sacral magnetic stimulation (TSMS). METHOD: Anorectal probes with an 8 × 8 array of electrodes spaced 1 cm apart were developed for recording HD-EMG of the external anal sphincter. These HD-EMG probes were used to map MEP amplitudes and latencies evoked via TSMS delivered through the Magstim Rapid2 (MagStim Company). Patients undergoing pelvic floor investigations were recruited for this IDEAL Stage 2a pilot study. RESULTS: Eight participants (median age 49 years; five female) were recruited. Methodological viability, safety and diagnostic workflow were established. The test was well tolerated with median discomfort scores ≤2.5/10, median pain scores ≤1/10 and no adverse events. Higher Faecal Incontinence Severity Index scores correlated with longer MEP latencies (r = 0.58, p < 0.001) and lower MEP amplitudes (r = -0.32, p = 0.046), as did St. Mark's Incontinence Scores with both MEP latencies (r = 0.49, p = 0.001) and MEP amplitudes (r = -0.47, p = 0.002). CONCLUSION: This HD-EMG probe in conjunction with TSMS presents a novel diagnostic tool for anorectal function assessment. Spatiotemporal assessment of magnetically stimulated MEPs correlated well with symptoms and offers a feasible, safe and patient-tolerable method of evaluating pudendal nerve and external anal sphincter function. Further clinical development and evaluation of these techniques is justified.

The influence of defaecating proctograms on clinical decision-making in pelvic floor disorders.

AIM: Defaecating proctogram (DP) studies have become an integral part of the evaluation of patients with pelvic floor disorders. However, their impact on treatment decision-making remains unclear. The aim of this study was to assess the concordance of decision-making by colorectal surgeons and the role of the DP in this process. METHOD: Four colorectal surgeons were presented with online surveys containing the complete history, examination and investigations of 106 de-identified pelvic floor patients who had received one of three treatment options: physiotherapy only, anterior Delorme's procedure or anterior mesh rectopexy. The survey assessed the management decisions made by each of the surgeons for the three treatments both before and after the addition of the DP to the diagnostic work-up. RESULTS: After the addition of the DP results; treatment choice changed in 219 (52%) of 424 surgical decisions and interrater agreement improved significantly from κ = 0.26 to κ = 0.39. Three of the four surgeons reported a significant increase in confidence. Agreement with the actual treatments patients received increased from κ = 0.21 to κ = 0.28. Intra-anal rectal prolapse on DP was a significant predictor of a decision to perform anterior mesh rectopexy. CONCLUSION: The DP improves interclinician agreement in the management of pelvic floor disorders and enhances the confidence in treatment decisions. Intra-anal rectal prolapse was the most influential DP parameter in treatment decision-making.

Outcomes for men undergoing rectal prolapse surgery - a systematic review.

AIM: Rectal prolapse is considered rare in men but the prevalence can be high in certain populations. It is unclear which surgical approach offers lower recurrence rates and better functional outcomes in men. The aim of this work was to determine the recurrence rates, complications and functional outcomes after prolapse surgery in men. METHOD: The MEDLINE, EMBASE and Scopus databases were systematically searched to identify studies on outcomes following surgical management of full-thickness rectal prolapse in men (over 18 years of age) published between 1951 and September 2022. Outcomes of interest included recurrence rate after surgery, bowel function, urinary function, sexual function and postoperative complications. RESULTS: Twenty-eight studies involving 1751 men were included. Two papers focused exclusively on men. Twelve studies employed a mixture of abdominal approaches, ten employed perineal approaches and six compared both. The recurrence rate varied across studies, ranging from 0% to 34%. Sexual and urinary function were poorly reported, but the incidence of dysfunction appears low. CONCLUSION: The outcomes of rectal prolapse surgery in men are poorly studied with small sample sizes and variable outcomes reported. There is insufficient evidence to recommend a specific repair approach based on the recurrence rate and functional outcomes. Further studies are required to identify the optimal surgical approach for rectal prolapse in men.

Anal Sphincter Length as Determined by 3-Dimensional Endoanal Ultrasound and Anal Manometry: A Study in Healthy Nulliparous Women.

OBJECTIVES: The normal female external anal sphincter (EAS) is shorter anteriorly than laterally and posteriorly. Furthermore, the thickness of the very proximal part of the circular EAS is thinner than 50% of the lateral and posterior EAS thickness. The extent of these features is not fully explored. The aim of this prospective study was to assess the normal anal sphincter with 3-dimensional (3D) endoanal ultrasound (EAUS) and to relate 3D EAUS length measurements to sphincter length determined by anal manometry. METHODS: Healthy premenopausal nulliparous women underwent anal manometry and 3D EAUS examinations. Two experienced colorectal surgeons independently assessed all scans, blinded to any patient data. RESULTS: A total of 43 women were included. Four scans were incomplete and excluded from the analysis. Interobserver agreement was fair to very good for the various length measurements. The mean length from the distal border of the puborectal muscle to the very proximal border of the anterior EAS (the anterior gap) was 4.4 (95% confidence interval, 3.9-4.9) mm, whereas the length to the level where the anterior EAS thickness was at least 50% of the lateral and posterior EAS thickness was 7.2 (95% confidence interval, 6.5-7.9) mm. Manometric sphincter length at rest did not correlate with any 3D EAUS length measurements. CONCLUSIONS: In the normal anterior female anal canal, the EAS is not present or appears with less than 50% of the thickness of the lateral and posterior EAS for the first 7.2 mm below the distal border of the puborectal muscle.

A Novel High-Density Electromyography Probe for Evaluating Anorectal Neurophysiology: Design, Human Feasibility Study, and Validation with Trans-Sacral Magnetic Stimulation.

Fecal incontinence (FI) substantially impairs quality of life and imparts a major socioeconomic burden. Anal sphincter injury and possibly pudendal nerve damage are considered common causes, however, current clinical methods for evaluating their function remain suboptimal. Electromyography (EMG) and pudendal nerve terminal latencies have been applied with some success, but are not considered standard practice due to uncertain accuracy and clinical value. In this study we developed and applied a novel anorectal high-density (HD) EMG probe in humans and pigs to acquire quantitative electrophysiological metrics of the anorectum. In the human trial we assessed somatic pathways and showed that EMG amplitude was greater for tight voluntary squeezes than light voluntary squeezes (0.03 ± 0.02 mV vs. 0.05 ± 0.03 mV). In a porcine model we applied trans-sacral magnetic stimulation to evoke extrinsically activated involuntary pathways and the resulting motor evoked potentials (MEP) were captured using the HD-EMG probe. The mean MEP amplitude at 50% magnetic stimulation intensity output (MSO) was significantly lower that the MEP amplitude at 85, 95 and 100% MSO (1.52 ± 0.50 mV vs. 3.10 ± 0.60 mV). In conclusion, the use of HD-EMG probe in conjunction with trans-sacral magnetic stimulation, for spatiotemporal mapping of anorectal EMG and MEP activity is anticipated to achieve new insights into FI and could offer improved diagnostic and prognostic biomarkers for anorectal dysfunction.

Pelvic mesh in colorectal pelvic floor surgery-implications of recent developments.

The use of mesh prostheses in pelvic surgery is under significant scrutiny. There are justifiable concerns around the transvaginal use of mesh products for POP surgery. The latter part of 2017 saw the announcement of wide-ranging regulatory actions relating to transvaginal mesh products, by the Therapeutic Goods Administration in Australia and subsequently Medsafe in New Zealand. In colorectal surgery, pelvic mesh is predominantly used in the treatment of rectal prolapse, with ventral mesh rectopexy (VMR) becoming popularised in recent years. The available evidence suggests that despite the current mesh controversy, VMR is an acceptable procedure, with functional advantages over other colorectal prolapse procedures. With only short-term outcome data available however, comparative studies and longer follow-up are required to answer the question of long-term mesh safety. In the meantime, there are areas where surgical practice can be optimised, in particular around reporting, training and patient education. The aims of this paper are to summarise the current status of pelvic floor mesh surgery and examine how this will impact colorectal pelvic floor surgery.

Early ileostomy closure: is there a downside?

BACKGROUND: A loop ileostomy is a common adjunct to formation of a low colorectal anastomosis. However, it is not without significant physical and psychological morbidity, and financial cost. Feasibility of early closure during the index admission has previously been reported. This pilot study examines the safety of early closure compared with traditional timing. METHODS: A retrospective audit of consecutive ileostomy closures performed in a tertiary colorectal unit from January 2008 to January 2010. Demographic data, treatment data and complications were collected by a single investigator from a prospective clinical audit database and hospital records. Patients undergoing early closure (within 10 days of the index operation) were compared with the traditional timing group. RESULTS: A total of 93 patients underwent closure of loop ileostomy during the study period (44 female; 49 male). Median patient age was 61 years. Nineteen patients (20%) underwent early closure. There were six wound infections in the early closure group (32%), and five in the traditional timing group (7%) (P = 0.01). There was no significant difference in other complications between the two groups. There was a significantly shorter overall hospital stay in the early closure group with a median stay of 14 days (range 10-26), and in the traditional timing group a median stay of 17 days (range 7-80) (P = 0.05). Seven patients (9%) in the traditional timing group had ileostomy-related complications. CONCLUSION: Early ileostomy closure appears to be associated with an increased wound infection rate but otherwise appears to be a safe alternative to traditional closure in selected patients and may reduce overall hospital stay.

'How I do it': TEM for tumors of the rectum.

INTRODUCTION: Transanal endoscopic microsurgery (TEM) has an established role in the management of benign rectal tumors. It also has an expanding role in the management of malignant tumors, which is more demanding for the clinician. It requires accurate histological and radiological assessment and draws on an expert understanding of the nature of local recurrence, metastasis, and the place of adjuvant therapies. DISCUSSION: A multidisciplinary approach is recommended. This paper discusses our institutional approach to TEM for benign and malignant tumors and covers some of the current management controversies.

Risk of dissemination with biopsy of colorectal liver metastases.

PURPOSE: Liver surgeons usually recommend against biopsy of colorectal liver metastases because of the risk of local dissemination. To date, only case reports describing this problem have been published. This study is an attempt to quantify the risk of biopsy-related dissemination. METHODS: A multicenter, retrospective review was undertaken of cases of colorectal liver metastases presenting for surgery that had undergone a preoperative biopsy. RESULTS: Two hundred thirty-one cases of colorectal liver metastases presenting for surgery were identified. Forty-three cases had undergone a preoperative biopsy (18.6 percent). Seven patients had evidence of dissemination related to the biopsy, giving a risk of dissemination of 16 percent (95 percent confidence interval, 7-30 percent). The risk of dissemination was not related to the type of biopsy. Within the follow-up period (median, 21 months), 3 of the 7 cases with evidence of dissemination and 11 of the 35 without dissemination were alive without disease. Twenty-five percent of the 36 cases without dissemination were resected, whereas 6 of the 7 cases with dissemination were resected. CONCLUSIONS: There is a significant risk of local dissemination with biopsy of colorectal liver metastases. In this series this was independent of the type of biopsy. There was no demonstrated effect on resectability or survival, but numbers were small, and the median follow-up was short.