Developing a new electromyography-based algorithm to diagnose the etiology of fecal incontinence

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.

Investigating Risk Factors for Complications after Ileostomy Reversal in Low Anterior Rectal Resection Patients: An Observational Study

Introduction: Defunctioning ileostomy has been widely used in patients undergoing low anterior rectal resection to reduce the rate of postoperative leakage. It is still not clear whether interval between primary procedure and ileostomy reversal has an impact on treatment outcomes. Methods: In our prospective observational study we reviewed 164 consecutive cases of patients who underwent total mesorectal excision with primary anastomosis. Univariate and multivariate regression models were used to search for risk factors for prolonged length of stay and complications after defunctioning ileostomy reversal. Receiver operating characteristic curves were utilized to set cut-off points for prolonged length of stay and perioperative morbidity. Results: In total, 132 patients were included in the statistical analysis. The median interval between primary procedure and defunctioning ileostomy reversal was 134 (range: 17-754) days, while median length of stay was 5 days (4-6 interquartile range (IQR)). Prolonged length of stay cut-off was established at 6 days. Regression models revealed that interval between primary surgery and stoma closure as well as complications after primary procedure are risk factors for complications after defunctioning ileostomy reversal. Prolonged length of stay has been found to be related primarily to interval between primary surgery and stoma closure. Conclusions: In our study interval between primary surgery and stoma closure along with complication occurrence after primary procedure are risk factors for perioperative morbidity and prolonged length of stay (LOS) after ileostomy reversal. The effort should be made to minimize the interval to ileostomy reversal. However, randomized studies are necessary to avoid the bias which appears in this observational study and confirm our findings.

Functional outcomes after resections for low rectal tumors: comparison of Transanal with laparoscopic Total Mesorectal excision

Background

Aim of this study was to evaluate functional outcomes of transanal total mesorectal excision (TaTME) in comparison to conventional laparoscopic approach (LaTME) in terms of low anterior resection syndrome (LARS).

Methods

Forty-six patients who underwent total mesorectal excision for low rectal cancer between 2013 and 2017 were enrolled. Primary outcome was the severity of faecal incontinence, assessed both before the treatment and 6 months after ileostomy reversal. LARS score and Jorge-Wexner scale were utilized to analyze its severity.

Results

Twenty (87%) from TaTME and 21 (91%) from LaTME group developed LARS postoperatively. There were no significant differences between groups in terms of LARS occurrence (p = 0.63) and severity. The median Wexner score was comparable in both groups (8 [IQR: 4–12] vs 7 [3–11], p = 0.83). Univariate analysis revealed that postoperative complications were a risk factor for LARS development (p = 0.02). Perioperative outcomes, including operative time, blood loss and intraoperative adverse events did not differ significantly between groups either. Five TaTME patients developed postoperative complications, while there were morbidity 6 cases in LaTME group. Quality of mesorectal excision was comparable with 20 and 19 complete cases in TaTME and LaTME groups, respectively.

Conclusions

TaTME provided comparable outcomes in terms of functional outcomes in comparison to LaTME for total mesorectal excision in low rectal cancers. Having said that, LARS prevalence is still high and requires further evaluation of the technique.

A quest for sphincter-saving surgery in ultralow rectal tumours-a single-centre cohort study

INTRODUCTION

Despite the progress in the treatment of colorectal cancer, there is still no optimal strategy for tumours located adjacent to the anal sphincter. This study aims to evaluate oncological and functional results of surgery for rectal cancer in unfavourable locations in proximity to anal sphincters.

MATERIALS AND METHODS

Patients with rectal cancer, which was either initially infiltrating the anal sphincter or located in the close proximity of the sphincter, were included in the study. Patients were submitted to extralevator abdominoperineal resection (APR), intersphincteric resection, or transanal total mesorectal excision (TaTME). Primary outcomes were perioperative data: operative time, blood loss, complications, length of stay (LOS), and 30-day mortality. Secondary outcomes were pathological quality of the specimens and functional outcome 6 months after defunctioning ileostomy closure.

RESULTS

Among patients with cancer adjacent to the anal sphincter, 13 (25%) underwent APR, 14 (27%) patients were submitted to intersphincteric resection, and 25 (48%) patients were treated with the TaTME approach. Operative time was 240 (210-270 IQR) for APR, 212.5 (170-260 IQR) for intersphincteric resection, and 270 (240-330 IQR) for TaTME (p = 0.018). Perioperative morbidity was 31% for APR, 36% for intersphincteric resections, and 12% for the TaTME group (p = 0.181). Complete mesorectal excision was achieved in 92% of specimens in the TaTME group, 93% in intersphincteric resections, and 78% in the APR group (p = 0.72). Median circumferential resection margin in APR was 6 mm (4-7 IQR), in intersphincteric resections 7.5 mm (2.5-10 IQR), and in the TaTME group 4 mm (2.8-8 IQR). All patients after intersphincteric resections developed major low anterior resection syndrome (LARS). Four patients in the TaTME group developed minor LARS, and 21 had major LARS.

CONCLUSION

Sphincter-saving rectal resections are a feasible alternative to APR with good clinical, pathological, and oncological outcomes. Intersphincteric resections and TaTME seem to be equal in terms of clinicopathological results. The functional outcome is yet to be investigated.

TRIAL REGISTRATION

The study was retrospectively registered in Thai Clinical Trials Registry (23-07-2018, ID TCTR20180724001 ).

Defunctioning ileostomy and mechanical bowel preparation may contribute to development of low anterior resection syndrome

INTRODUCTION

Laparoscopic surgery is an approved technique in colorectal cancer treatment. Functional and quality-of-life studies have revealed significant changes in faecal continence.

AIM

To assess the incidence and risk factors of low anterior resection syndrome (LARS) in patients undergoing rectal resections for cancer.

MATERIAL AND METHODS

We enrolled patients undergoing rectal resections in a general surgery department of a university hospital. The primary outcomes were the Jorge-Wexner scale and the LARS score 6 months after the end of treatment. The secondary outcomes were the risk factors for LARS development.

RESULTS

Fifty-six patients were included; 15 (26%) developed major LARS and 10 (18%) had minor LARS at 6 months. In univariate analysis the risk factors were: preoperative radiotherapy (p < 0.001, OR = 11.9, 95% CI: 2.98-47.48); shorter distance of the tumour from the anal verge (p = 0.001, OR = 0.69, 95% CI: 0.55-0.86); bowel preparation (p = 0.01, OR = 6.27, 95% CI: 1.51-26.07); low anterior rectal resection (p = 0.01, OR = 17.07, 95% CI: 1.86-156.83); and protective ileostomy (p = 0.001, OR = 15.97, 95% CI: 4.07-61.92). The risk factors for a higher Jorge-Wexner score in univariate analysis were greater diameter of tumour (p = 0.035), radiotherapy (p = 0.001), shorter distance from the anal verge (p = 0.002), bowel preparation (p = 0.042), low anterior rectal (LAR) (p = 0.01), ileostomy (p = 0.001), perioperative complications (p = 0.032), and readmission within 30 days (p = 0.034). In the multivariate analysis, readmissions and perioperative complications were significant.

CONCLUSIONS

In addition to typically described risk factors, two new ones have been identified. Mechanical bowel preparation and defunctioning ileostomy may also contribute to LARS development. However, due to the limitations of this study our observations require further confirmation in future trials.

Implantation of autologous muscle-derived stem cells in treatment of fecal incontinence: results of an experimental pilot study

Background

The aim of this study is to present results of the implantation of autologous myoblasts into the external anal sphincter (EAS) in ten patients with fecal incontinence.

Methods

After anatomical and functional assessment of the patients’ EAS, a vastus lateralis muscle open biopsy was performed. Stem cells were extracted from the biopsy specimens and cultured in vitro. Cell suspensions were then administered to the EAS. Patients were scheduled for follow-up visits in 6-week intervals. Total follow-up was 12 months.

Results

All biopsy and cell implantation procedures were performed without complications. Nine of the patients completed a full 12-month follow-up. There was subjective improvement in six patients (66.7 %). In manometric examinations 18 weeks after implantation, squeeze anal pressures and high-pressure zone length increased in all patients, with particularly significant sphincter function recovery in five patients (55.6 %). Electromyographic (EMG) examination showed an increase in signal amplitude in all patients, detecting elevated numbers of propagating action potentials. Twelve months after implantation two patients experienced deterioration of continence, which was also reflected in the deterioration of manometric and EMG parameters. The remaining four patients (44.4 %) still described their continence as better than before implantation and retained satisfactory functional examination parameters.

Conclusions

Implantation of autologous myoblasts gives good short-term results not only in a subjective assessment, but also in objective functional tests. It seems that this promising technology can improve the quality of life of patients with fecal incontinence, but further study is required to achieve better and more persistent results.

Magnetic resonance imaging and endorectal ultrasound for diagnosis of rectal lesions

Endorectal ultrasonography (ERUS) and magnetic resonance imaging (MRI) allow exploring the morphology of the rectum in detail. Use of such data, especially assessment of the rectal wall, is an important tool for ascertaining the perianal fistula localization as well as stage of the cancer and planning it appropriate treatment, as stage T3 tumors are usually treated with neoadjuvant therapy, whereas T2 tumors are initially managed surgically. The only advantage of ERUS over MRI is the possibility of assessing T1 tumors that could be treated by transanal endoscopic microsurgery. However, MRI is better for visualizing most radiological prognostic features in rectal or anal cancer such as a circumferential resection margin less than 1 mm, T stage at T1-T2 or T3 tumors with extramural extension less than 5 mm, absence of extramural vascular invasion, N stage at N0/N1, and tumors located in the middle or upper third of the rectum. It can also evaluate the intersphincteric space or levator ani muscle involvement. Increased signal on diffusion weighted imaging (DWI) and low apparent diffusion coefficient (ADC) values as well as an irregular contour and heterogeneous internal signal intensity seem to predict the involvement of pelvic lymphatic nodes better than their size alone. Computed tomography as well as other examination techniques, including digital rectal examination, contrast edema, recto- and colonoscopy, are less useful in staging of rectal cancer but still are very important screening tools.