Continuous intraoperative monitoring of pelvic autonomic nerves during TME to prevent urogenital and anorectal dysfunction in rectal cancer patients (NEUROS): a randomized controlled trial

Pelvic Intraoperative Neuromonitoring Prevents Dysfunction in Patients With Rectal Cancer: Results From a Multicenter, Randomized, Controlled Clinical Trial of a NEUROmonitoring System (NEUROS)

OBJECTIVE

This NEUROmonitoring System (NEUROS) trial assessed whether pelvic intraoperative neuromonitoring (pIONM) could improve urogenital and ano-(neo-)rectal functional outcomes in patients who underwent total mesorectal excisions (TMEs) for rectal cancer.

BACKGROUND

High-level evidence from clinical trials is required to clarify the benefits of pIONM.

METHODS

NEUROS was a 2-arm, randomized, controlled, multicenter clinical trial that included 189 patients with rectal cancer who underwent TMEs at 8 centers, from February 2013 to January 2017. TMEs were performed with pIONM (n=90) or without it (control, n=99). The groups were stratified according to neoadjuvant chemoradiotherapy and sex, with blocks of variable length. Data were analyzed according to a modified intention-to-treat protocol. The primary endpoint was a urinary function at 12 months after surgery, assessed with the International Prostate Symptom Score, a patient-reported outcome measure. Deterioration was defined as an increase of at least 5 points from the preoperative score. Secondary endpoints were sexual and anorectal functional outcomes, safety, and TME quality.

RESULTS

The intention-to-treat analysis included 171 patients. Marked urinary deterioration occurred in 22/171 (13%) patients, with significantly different incidence between groups (pIONM: n=6/82, 8%; control: n=16/89, 19%; 95% confidence interval, 12.4-94.4; P =0.0382). pIONM was associated with better sexual and ano-(neo)rectal function. At least 1 serious adverse event occurred in 36/88 (41%) in the pIONM group and 53/99 (54%) in the control group, none associated with the study treatment. The groups had similar TME quality, surgery times, intraoperative complication incidence, and postoperative mortality.

CONCLUSION

pIONM is safe and has the potential to improve functional outcomes in rectal cancer patients undergoing TME.

Three-dimensional versus two-dimensional laparoscopic surgery for rectal cancer: better promote postoperative sexual and urinary function of a propensity-matched study

Laparoscopic total mesorectal excision (TME) with autonomic nerve preservation (ANP) is a common procedure for rectal cancer (RC), associated with a high prevalence of postoperative urogenital and anorectal dysfunctions. Compared to 2D laparoscopy, 3D laparoscopy provides better depth perception of the surgical field and hand-eye coordination to achieve better outcomes. We compared the performance of 2D and 3D laparoscopy on preserving urogenital and anorectal function in TME+ANP surgery for rectal cancer using propensity-score matching. Data were collected from consecutive male patients who underwent 3D or 2D laparoscopic TME+ANP for primary RC at our institution between March 2012 and December 2020. The primary outcome was sexual and urinary function 1 year after surgery. A total of 450 male patients were eligible. After 1:1 matching, 146 cases were included in each group for analysis. One year after surgery, the prevalence of sexual dysfunction (International Index of Erectile Function score <26) was 8.22% in the 3D laparoscopic group and 44.52% in the 2D laparoscopic group, respectively (P=0.000) and a significant difference in the incidence of urinary retention was observed (n=3 and 24, respectively (P=0.000)). Moreover, blood loss, operative time, duration of hospital stay, and the time to first flatus in the 3D laparoscopic group were significantly less than in the 2D laparoscopic group. In conclusion, 3D laparoscopic TME is associated with lower incidences of postoperative sexual and urinary dysfunction than 2D laparoscopic TME for rectal cancer in male patients.

Development and evaluation of a Japanese prediction model for low anterior resection syndrome after rectal cancer surgery

Background

Low anterior resection syndrome (LARS) is the most common complication after rectal cancer resection. We aimed to identify LARS' predictive factors and construct and evaluate a predictive model for LARS.

Methods

This retrospective study included patients with rectal cancer more than 1 year after laparoscopic or robotic-assisted surgery. We administered a questionnaire to evaluate the degree of LARS. In addition, we examined clinical characteristics with univariate and multivariate analysis to identify predictive factors for major LARS. Finally, we divided the obtained data into a learning set and a validation set. We constructed a predictive model for major LARS using the learning set and assessed the predictive accuracy of the validation set.

Results

We reviewed 160 patients with rectal cancer and divided them into a learning set (n = 115) and a validation set (n = 45). Univariate and multivariate analyses in the learning set showed that male (odds ratio [OR]: 2.88, 95% confidence interval [95%CI] 1.11–8.09, p = 0.03), age < 75 years (OR: 5.87, 95%CI 1.14–47.25, p = 0.03) and tumors located < 8.5 cm from the AV (OR: 7.20, 95%CI 2.86–19.49, p < 0.01) were significantly related to major LARS. A prediction model based on the patients in the learning set was well-calibrated.

Conclusions

We found that sex, age, and tumor location were independent predictors of major LARS in Japanese patients that underwent rectal cancer surgery. Our predictive model for major LARS could aid medical staff in educating and treating patients with rectal cancer before and after surgery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02295-w.

How to dissect the pelvic nerves: from microanatomy to surgical rules. An evidence-based clinical review

Background: Advanced gynaecological procedures often include extensive pelvic dissections, with the nervous structures involved in the disease. Nerve-sparing and preservation is a key factor in reducing postoperative morbidity. Objectives: The goal of this review is to describe in detail the structure of the pelvic nerves and to gather information from other surgical specialties to give recommendations for safe nerve dissection applied in different gynaecological subspecialties. Materials and methods: An extensive literature review was carried out in PubMed and Google Scholar. The search included articles concerning peripheral nerve anatomy, mechanisms of injury and different dissection techniques, with the most exhaustive being analysed for the review. Articles from different fields of medicine like orthopaedics, plastic surgery, maxillofacial surgery dealing with peripheral nerve injuries and repair have been reviewed. Results: The following review demonstrates the in-depth anatomy and mechanism of injury of the peripheral nerves, describes the different techniques for neurolysis and proposes some directions for safe nerve dissection. Conclusion: When performing complex gynaecological surgeries, the surgeon should avoid unnecessary nerve handling, apply nerve-sparing techniques whenever possible and use the new devices to preserve the nervous structures. Advanced gynaecological surgeries should be performed in specialised centres by expert surgeons with comprehensive knowledge in neuropelveology. What is new? To our knowledge, this is the first article focused on peripheral nerves that collects data from such a wide range of specialties in order to propose the most comprehensive recommendations that could be applied in pelvic surgery.

A new method of intraoperative pelvic neuromonitoring: a preclinical feasibility study in a porcine model

Low anterior resections (LAR) are frequently associated with complications such as urinary and fecal incontinence as well as sexual disorders. Typical risk factors are rectal cancer with low tumor location, preoperative radiotherapy, and surgery-related damage of pelvic autonomic nerves. As preserving the pelvic autonomic nerves without any technical assistance is challenging, the objective of this preclinical study was to investigate the technical feasibility of a new method for intraoperative pelvic neuromonitoring. Twelve female pigs undergoing low anterior resections were involved in a prospective preclinical study. Intraoperative pelvic neuromonitoring included direct pelvic nerve stimulation and tissue impedance measurement on the urinary bladder and the rectum for the identification of efferent pelvic nerves in the surgical area. Immunohistochemistry was used to verify the results. Smooth muscle contraction of the urinary bladder and/or the rectum in response to direct stimulation of the innervating nerves was detectable with impedance measurement. The macroscopic contraction of both the urinary bladder and the rectum correlated with a change in tissue impedance compared to the status before contraction. Thus, it was possible to identify pelvic nerves in the surgical area, which allows the nerves to be preserved. The results indicate a reliable identification of pelvic autonomic nerves, which allows nerve damage to be prevented in the future.

Systematic review and meta-analysis of randomized controlled trials evaluating the effect of the level of ligation of inferior mesenteric artery on functional outcomes in rectal cancer surgery

BACKGROUND

This systematic review and meta-analysis studied the role of high (HL) versus low (LL) inferior mesenteric artery (IMA) ligation on genitourinary and defecatory dysfunction in patients who had undergone resection for rectal cancer (RC).

METHODS

A systematic literature search of four major databases was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Randomized controlled trials (RCTs) comparing HL and LL of IMA in RC surgery were identified. Those studies that looked at genitourinary or defecatory dysfunction were included. Random-effects modeling to summarize statistics was performed. The risk of bias was assessed using Cochrane's Risk-of-Bias tool 2.

RESULTS

Three RCTs were included. There was clinical heterogeneity with regard to cancer stage and location as well as operative techniques and adjuvant treatments. Functional outcomes (FO) that were reported by at least two studies were International Consultation on Incontinence Questionnaire (ICIQ), International Index for Erectile Function (IIEF), Jorge-Wexner incontinence score (J-W). Difference was observed in ICIQ at 9 months after surgery favoring LL (standard mean difference: - 0.66; 95% confidence intervals (CI): - 0.92, - 0.40; P = 0.37; I 2 = 0%). Difference was also observed in IIEF at 9 months favoring LL (mean difference: 7.43; CI: 1.86, 13.00; P = 0.16; I 2 = 50%).

CONCLUSIONS

Although our study has demonstrated the superiority of LL in genitourinary function preservation, these results should be taken with consciousness due to significant heterogeneity between included studies, small sample size, and potential bias. More high-quality studies are needed.

PROSPERO

CRD4202121099  https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021210998.

Low anterior resection syndrome: can it be prevented?

Surgery remains the cardinal treatment in colorectal cancers but changes in bowel habits after rectal cancer surgery are common and disabling conditions that affect patients' quality of life. Low anterior resection syndrome is a disorder of bowel function after rectal resection resulting in a lowering of the QoL and recently has been defined by an international working group not only by specified symptoms but also by their consequences. This review aims to explore an extensive bibliographic research on preventive strategies for LARS. All "modifiable variables," quantified by the LARS Score, such as type of anastomosis, neoadjuvant therapy, surgical strategy, and diverting stoma, were evaluated, while "non-modifiable variables" such as age, sex, BMI, ASA, preoperative TMN, tumor height, and type of mesorectal excision were excluded from the comparative analysis. The role of defunctioning stoma, local excision, neoadjuvant radiotherapy, and non operative management seems to significantly affect risk of LARS, while type of anastomosis and surgical TME approach do not impact on LARS incidence or gravity in the long term period. Although it is established that some variables are associated with a greater onset of LARS, in clinical practice, technical difficulties and oncological limits often make difficult the application of some prevention plans. Transtomal irrigations, intraoperative neuromonitoring, pelvic floor rehabilitation before stoma closure, and early transanal irrigation represent new arguments of study in preventive strategies which could, if not eliminate the symptoms, at least mitigate them.

Intraoperative neuromonitoring in rectal cancer surgery: a systematic review and meta-analysis

PURPOSE

The aim of this study is to evaluate the role of pelvic intraoperative neuromonitoring (pIONM) in rectal cancer surgery.

METHODS

A systematic review of the literature and a meta-analysis were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and the Cochrane Handbook for Systematic Reviews of Interventions.

RESULTS

Overall, nine studies were identified. Quantitative analysis was performed only in three trials. Bilateral pIONM improved postoperative anorectal and urogenital functional outcomes. However, unilateral pIONM displayed a significant effect only on erectile function (p = 0.001).

CONCLUSIONS

Our findings suggest a positive effect of pIONM on postoperative functional outcomes and quality of life after rectal cancer surgery. Due to several limitations, further trials are required in order to elucidate the exact role of pIONM.

Male erectile function after treatment for colorectal cancer: a population-based cross-sectional study

AIM

The aim of this work was to determine the knowledge gap in the field of erectile function (EF) after colorectal cancer surgery and investigate and compare long-term male EF in colon and rectal cancer survivors in a national population.

METHOD

Danish male patients alive without evidence of recurrence who were treated for colon or rectal cancer between May 2001 and December 2014 were invited to participate. Using the International Index of Erectile Function (IIEF) score the derived dichotomized erectile dysfunction (ED) was defined as moderate/severe or no/mild. Patients were grouped based on type of surgery [colon resection, rectal resection (RR) or local resection] and stratified for stoma, preoperative radiotherapy (RT), age and American Society of Anesthesiologists (ASA) score.

RESULTS

Of 10 037 eligible patients, 4334 responded (43.18%). The EF score was significantly lower for RR (mean 12.14) compared with both colon resection (mean 15.82) and local resection (mean 14.81) (p < 0.0001). No significant difference between colon resection and local resection was found (p = 0.29). Both a stoma and the use of RT were independent risk factors for ED. After excluding patients with stoma and RT and adjusting for age and ASA score, RR still had a higher risk of ED (OR 1.42, CI 1.20-1.67) compared with colon resection.

CONCLUSION

RR has a negative affect on EF. No difference between patients who underwent colon resection and local resection was found. RT and stoma were independent risk factors for ED.

Tools for fecal incontinence assessment: lessons for inflammatory bowel disease trials based on a systematic review

BACKGROUND

Fecal incontinence is a disabling condition affecting up to 20% of women.

OBJECTIVE

We investigated fecal incontinence assessment in both inflammatory bowel disease and non-inflammatory bowel disease patients to propose a diagnostic approach for inflammatory bowel disease trials.

METHODS

We searched on Pubmed, Embase and Cochrane Library for all studies on adult inflammatory bowel disease and non-inflammatory bowel disease patients reporting data on fecal incontinence assessment from January 2009 to December 2019.

RESULTS

In total, 328 studies were included; 306 studies enrolled non-inflammatory bowel disease patients and 22 studies enrolled inflammatory bowel disease patients. In non-inflammatory bowel disease trials the most used tools were the Wexner score, fecal incontinence quality of life questionnaire, Vaizey score and fecal incontinence severity index (in 187, 91, 62 and 33 studies). Anal manometry was adopted in 41.2% and endoanal ultrasonography in 34.0% of the studies. In 142 studies (46.4%) fecal incontinence evaluation was performed with a single instrument, while in 64 (20.9%) and 100 (32.7%) studies two or more instruments were used. In inflammatory bowel disease studies the Wexner score, Vaizey score and inflammatory bowel disease quality of life questionnaire were the most commonly adopted tools (in five (22.7%), five (22.7%) and four (18.2%) studies). Anal manometry and endoanal ultrasonography were performed in 45.4% and 18.2% of the studies.

CONCLUSION

Based on prior validation and experience, we propose to use the Wexner score as the first step for fecal incontinence assessment in inflammatory bowel disease trials. Anal manometry and/or endoanal ultrasonography should be taken into account in the case of positive questionnaires.

Optimising functional outcomes in rectal cancer surgery

Background

By improved surgical technique such as total mesorectal excision (TME), multimodal treatment and advances in imaging survival and an increased rate of sphincter preservation have been achieved in rectal cancer surgery. Minimal-invasive approaches such as laparoscopic, robotic and transanal-TME (ta-TME) enhance recovery after surgery. Nevertheless, disorders of bowel, anorectal and urogenital function are still common and need attention.

Purpose

This review aims at exploring the causes of dysfunction after anterior resection (AR) and the accordingly preventive strategies. Furthermore, the indication for low AR in the light of functional outcome is discussed. The last therapeutic strategies to deal with bowel, anorectal, and urogenital disorders are depicted.

Conclusion

Functional disorders after rectal cancer surgery are frequent and underestimated. More evidence is needed to define an indication for non-operative management or local excision as alternatives to AR. The decision for restorative resection should be made in consideration of the relevant risk factors for dysfunction. In the case of restoration, a side-to-end anastomosis should be the preferred anastomotic technique. Further high-evidence clinical studies are required to clarify the benefit of intraoperative neuromonitoring. While the function of ta-TME seems not to be superior to laparoscopy, case-control studies suggest the benefits of robotic TME mainly in terms of preservation of the urogenital function. Low AR syndrome is treated by stool regulation, pelvic floor therapy, and transanal irrigation. There is good evidence for sacral nerve modulation for incontinence after low AR.

Fecal incontinence after total mesorectal excision for rectal cancer-impact of potential risk factors and pelvic intraoperative neuromonitoring

BACKGROUND

Fecal incontinence frequently occurs after total mesorectal excision for rectal cancer. This prospective study analyzed predictive factors and the impact of pelvic intraoperative neuromonitoring at different follow-up intervals.

METHODS

Fifty-two patients were included undergoing total mesorectal excision for rectal cancer, and 29 under control of pelvic intraoperative neuromonitoring. Fecal incontinence was assessed using the Wexner Score at 3 and 6 months after stoma closure (follow-ups 1 and 2) as well as 1 and 2 years after surgery (follow-ups 3 and 4). Risk factors were identified by means of logistic regression.

RESULTS

New onset of fecal incontinence was significantly lower in the neuromonitoring group at each follow-up (follow-up 1: 2 of 29 patients (7%) vs. 8 of 23 (35%), (p = 0.014); follow-up 2: 3 of 29 (10%) vs. 9 of 23 (39%), (p = 0.017); follow-up 3: 5 of 29 (17%) vs. 11 of 23 (48%), p = 0.019; follow-up 4: 6 of 28 (21%) vs. 11 of 22 (50%), p = 0.035). Non-performance of neuromonitoring was found to be an independent predictor for fecal incontinence throughout the survey. Neoadjuvant chemoradiotherapy was an independent predictor in the further course 1 and 2 years after surgery.

CONCLUSIONS

Performance of pelvic intraoperative neuromonitoring is associated with significantly lower rates of fecal incontinence. Neoadjuvant chemoradiotherapy was found to have negative late effects. This became evident 1 year after surgery.

Intuitive Visualization of Innervation Zones Based on Surface-EMG Signals

The purpose of this study was to develop a user-friendly presentation of surface-EMG data in near-time for intraoperative nerve-monitoring. We have built a novel surface-EMG probe as a diagnostic device to investigate innervation patterns of sphincter muscles in further clinical diagnostic studies. S-EMG data were recorded from 20 healthy volunteers from the orbicularis oris muscles. We developed an automated analysis based on correlation in order to find phase inversions and thus innervation zones automatically. We compared our automated analysis with manual, visual analysis. Both techniques were reviewed for variance and showed reproducible results. Data from automated analysis were compared to visually analyzed data showing high consistency. Based on our automated analysis, we created an intuitive visualization of all measurements per person. We displayed the quality and quantity of the phase inversions found in a subject thus allowing for simple identification of innervation zones. We conclude that our set-up showed sufficient reliability for detection of motoric endplate activity and can be used for further clinical neurophysiological studies.