Intraoperative identification and neurophysiologic parameters to verify pelvic autonomic nerve function during total mesorectal excision for rectal cancer

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.

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.

Intraoperative neuromonitoring of hypogastric plexus branches during surgery for rectal cancer - preliminary report

AIM

The aim of this study was to present our preliminary experience with intraoperative neuromonitoring during rectal resection.

MATERIALS AND METHODS

We qualified 4 patients (2 women, 2 men; age 42 - 53 years) with rectal cancer for surgery with intraoperative neuromonitoring. In all patients, functional tests of the anorectal area were performed before surgery. Action potentials from the sphincter complex in response to nerve fiber stimulation were recorded with electrodes implanted before surgery. Moreover, we inserted a standard, 18FR Foley's urinary catheter to which a T-tube was connected to allow urine outflow and measurement of pressure changes in the bladder induced by detrusor contractions during stimulation.

RESULTS

Setting up neuromonitoring prolonged surgery time by 30 to 40 minutes, or even by 60 to 80 minutes in the case of the first two patients. Neuromonitoring itself took additional 20 to 30 minutes during surgery. In all patients, we stimulated branches of the inferior hypogastric plexus in their anatomical position during dissection. In three patients, we evoked responses both from the bladder and the sphincter in all planes of stimulation. In one patient, there was no response from the left side of the bladder, and in the same patient, we observed symptoms of neurogenic bladder.

CONCLUSIONS

Based on the available literature and our own experience, we state that monitoring of bladder pressure and electromyographic signals from rectal sphincters enables visualization and preservation of autonomic nervous system structures, both sympathetic and parasympathetic. Intraoperative signals seem to be correlated with clinical presentation and functional examinations after surgery. In order to objectify our results, it is necessary to perform functional examinations before and after surgery in a larger group of patients.

Pelvic autonomic nerve preservation in radical rectal cancer surgery: changes in the past 3 decades

The advent of total mesorectal excision (TME) together with minimally invasive techniques such as laparoscopic colorectal surgery and robotic surgery has improved surgical results. However, the incidence of bladder and sexual dysfunction remains high. This may be particularly distressing for the patient and troublesome to manage for the surgeon when it does occur. The increased use of neoadjuvant and adjuvant radiotherapy is also associated with poorer functional outcomes. In this review, we evaluate current understanding of the anatomy of pelvic nerves which are divided into the areas of the inferior mesenteric artery pedicle, the lateral pelvic wall and dissection around the urogenital organs. Surgical techniques in these areas are discussed. We also discuss the results in functional outcomes of the various techniques including open, laparoscopic and robotic over the last 30 years.

Preliminary results of the first quality assurance project in rectal cancer in Poland

When compared with other EU countries, Poland is in the last place in terms of efficacy of rectal cancer treatment. In order to remedy this situation, in 2008 Polish centres were given the opportunity to participate in an international programme for evaluating the treatment efficacy.The aim of the study was to present the results obtained during the first two years of research.

MATERIAL AND METHODS

The study protocol covered 71 questions concerning demographic data, diagnostics, risk factors, peri- and post-operative complications, histopathology, and treatment plan at discharge. The patient and unit data were kept confidential.

RESULTS

From 1 January 2008 to 30 December 2009, there were 709 patients recorded, of which 55.9% were males. At least one risk factor was found in approx. 3/4 of patients, while approx. 1/3 of patients were classified to group 3 and 4 according to ASA. The mean distance of the tumour from the anal margin was 8.5 cm; approx. 70% of patients were in the clinical stages cT3 and cT4; metastases were observed in 18.8%. Transrectal endoscopic ultrasonography (TREUS) was performed in 23.7% of patients, magnetic resonance imaging (MRI) in 2.5% and computed tomography (CT) scan - in 48.1%. In close to half of the patients, anterior or low anterior resection of the rectum was performed, and abdominoperineal resection in 1/4 of the patients. Anastomotic leakage was seen in 3.8% of patients, while 1.8% died during hospitalisation.

CONCLUSIONS

It should be strived after that all the centres undertaking the treatment of rectal cancer should participate in the quality assurance programme. This should enable the achievement of good therapeutic results in patients with rectal cancer treated in Polish centres.

Continuous intraoperative monitoring of autonomic nerves during low anterior rectal resection: an innovative approach for observation of functional nerve integrity in pelvic surgery

PURPOSE

The aim of this study was to develop a methodological setup for continuous intraoperative neuromonitoring with intent to improve nerve-sparing pelvic surgery.

METHODS

Fourteen pigs underwent low anterior rectal resection. Continuous stimulation of pelvic autonomic nerves was carried out with a newly developed tripolar surface electrode during lateral, anterolateral, and anterior mesorectal dissection. Neuromonitoring was performed under electromyography of the autonomic innervated internal anal sphincter.

RESULTS

Continuous neuromonitoring resulted in significantly increased electromyographic amplitudes of the internal anal sphincter, confirming intact innervation throughout the whole dissection in each animal (median 0.9 μV, interquartile range 0.5; 1.5 vs. median 3.4 μV, interquartile range 2.1; 4.7) (p < 0.001). The median dissection time in each animal was 10 min within a median number of ten (range 8-13) tripolar electric stimulations.

CONCLUSION

The present study is the first to demonstrate that continuous intraoperative monitoring of pelvic autonomic nerves during low anterior rectal resection is feasible.

Sexual and urinary dysfunction after proctectomy for rectal cancer

Sexual and urinary dysfunction occur frequently after rectal surgery. Total mesorectal excision (TME) is currently the optimal technique for resection of rectal cancer, providing superior carcinological and functional outcomes. Age, pre-operative radiation therapy, abdominoperineal resection, and surgery which fails to respect the "sacred planes" of TME are the four major risk factors for post-operative sexual and urinary sequelae. In the era of TME, postoperative sexual dysfunction ranges from 10-35%, depending on the scores used to assess it, while urinary sequelae have decreased to less than 5%. The place of laparoscopic surgery remains to be defined, particularly with respect to these complications. It is essential to inform the patient pre-operatively about the possibility of such disorders not only for patient informed consent but also to help with correct post-operative management of the problem. Management is multifaceted, and includes psychological, pharmacological, and sometimes surgical therapy.

Intraoperative electrostimulation objectifies the assessment of functional nerve preservation after mesorectal excision

BACKGROUND

To improve nerve-sparing surgery, intraoperative electrical stimulation of pelvic autonomic nerves (INS) has been proposed in urology, gynecology, and visceral surgery. The aim of this study was to assess the impact of INS while monitoring intravesical pressure on the accurate evaluation of pelvic autonomic nerve preservation (PANP) after mesorectal excision. It was sought to determine whether this confirmation is useful in the prediction of postoperative urinary function.

METHODS

Sixty-two patients with mesorectal exzision for rectal cancer were examined prospectively. PANP was assessed visually by the surgeon and with INS. Bladder function was evaluated by post voiding residual volume measurement, rate of recatheterization, rate of long-term urinary catheterisation, and the international prostatic symptom score with quality of life index.

RESULTS

INS confirmed bilateral preservation of parasympathetic nerves in 46 patients (74%), and in 10 patients (16%) in at least one side. In six patients (10%), INS failed to confirm PANP. Eleven patients (18%) developed urinary symptoms postoperatively. INS results had a higher sensitivity than visual assessment by the surgeon (82 vs 46%). Values for specificity ranged at 90 and 92%, respectively. Accuracy of INS in predicting PANP was higher (88 vs 83%). The correlation between urinary function and the findings on INS was good (kappa-value: 0.65), correlation between urinary function and visual assessment by the surgeon was fair (kappa-value: 0.40).

CONCLUSION

INS, while monitoring intravesical pressure, accurately predicts bladder function after mesorectal excision. It may provide further insight into pelvic autonomic nerve sparing techniques.

An audit of outcomes in colorectal cancer in China

AIM

This study was designed to analyses the correlation between the extent of lymph node excision and the prognosis of colorectal cancer and to discuss the clinical significance of excision of lymph nodes adjacent to mesenteric artery pedicle.

METHODS

A total of 1409 patients with colorectal cancer who had the primary radical operation in our hospital during 1985 to 2000 was analyzed in this study. They were divided into two groups according to whether undergone an excision of lymph nodes adjacent to mesenteric artery pedicle. There were 857 patients in the excision group and 552 patients in the non-excision group. Comparison of prognoses was based on the follow-up results.

RESULTS

The 1-year, 3-year and 5-year overall survival rates of the excision group were 90%, 81% and 77%, while those of the non-excision group were 91%, 84% and 79%, respectively. The 1-year, 3-year and 5-year tumor-free survival rates of excision group were 90%, 79% and 75%, while those of the non-excision group were 90%, 83% and 76%. Kaplan-Meier analysis did not show any difference in overall survival rate or tumor-free survival rate between these two groups (P>0.05). After follow-up of 12 to 289 months there were 42 cases of local recurrence and 79 cases of metastases in the excision group. In the non-excision group local recurrence occurred in 30 cases and 60 patients had metastases. There was no difference in the rates of local recurrence and metastasis between these two groups. Multivariate correlation analyses showed that the excision of lymph nodes adjacent to mesenteric artery pedicle was not statistically correlated to recurrence, metastasis and survival time after radical operation of colorectal cancer.

CONCLUSION

In radical operation of colorectal cancer it is not necessary to perform excision of lymph nodes adjacent to mesenteric artery pedicle which is not correlated to prognosis.

The LANN Technique to Reduce Postoperative Functional Morbidity in Laparoscopic Radical Pelvic Surgery

BACKGROUND

We investigated the feasibility and advantages of introducing Laparoscopic Neuro-Navigation (LANN) into the field of laparoscopic gynecologic radical pelvic surgery.

STUDY DESIGN

In a prospective pilot study, 261 consecutive patients underwent laparoscopic radical pelvic surgery for cervical cancer or deep infiltrating endometriosis of the parametria. During the procedure, dissection and electrostimulation, and consequently, sparing of the pelvic parasympathetic nerves by transection of the parametria, were performed. Postoperative bladder dysfunction was documented.

RESULTS

Laparoscopic dissection and electrostimulation of the pelvic splanchnic nerves were feasible in all patients without any complications, and the rate of postoperative bladder dysfunction was considerably reduced, to less than 1% of the patients.

CONCLUSIONS

The parasympathetic nerve-sparing method using the Laparoscopic Neuro-Navigation technique in laparoscopic radical pelvic gynecologic surgery is a feasible and reproducible technique that preserves postoperative bladder function.

Intraoperative electrical stimulation of the pelvic splanchnic nerves during nerve-sparing radical hysterectomy

OBJECTIVES

This study sought to determine whether intraoperative electrical stimulation (IES) of pelvic splanchnic nerves (PSNs) while monitoring bladder contraction was useful to predict postoperative bladder function during conventional nerve-sparing radical hysterectomy.

METHODS

Seventeen patients with stage Ib or IIa cervical cancer underwent conventional radical hysterectomy. IES was performed in all cases, stimulating the roots of PSN, the posterior sheath of the vesicouterine ligament (PVL) and the dorsal area of the ligament. After resection of the uterus, the PSN roots were stimulated again. Bladder function was evaluated by urodynamic study (UDS) preoperatively and 3 months after surgery.

RESULTS

The results of IES were consistent with bladder function evaluated by postoperative UDS. In 13 of 17 cases, an increased intravesical pressure was observed with IES of the PSN roots after uterus resection. Nine of 13 cases showed marked detrusor contraction with UDS 3 months after surgery and were able to void without using abdominal pressure except in one case. In the remaining 4 of 17 cases, no response could be detected to IES on either side. Three cases voided using abdominal pressure and one used clean intermittent self-catheterization without spontaneous voiding.

CONCLUSIONS

IES while monitoring intravesical pressure during radical hysterectomy represents a technically simple and useful procedure for the prediction of postoperative bladder function.

Major urinary dysfunction after mesorectal excision for rectal carcinoma

Background

Urinary dysfunction may occur after mesorectal excision and pelvic autonomic nerve preservation (PANP) in patients with rectal carcinoma. The aim of this prospective study was to identify factors predictive of long-term urinary catheterization.

Methods

Two hundred and ten patients without significant urological problems underwent resection of rectal cancer with mesorectal excision. The number of patients with complete, partial or no identification of the nerves was documented and correlated with possible predictive factors for postoperative major urinary dysfunction.

Results

Eight patients (3·8 per cent) required long-term urinary catheterization: two after complete PANP (two of 168) and six in whom PANP was incomplete (six of 42) (P = 0·001). Multiple regression analysis identified incomplete PANP (odds ratio 13·8 (95 per cent confidence interval 2·7 to 71·3); P = 0·002) as a predictive factor for major urinary dysfunction.

Conclusion

Major urinary dysfunction after mesorectal excision for rectal cancer is associated with an incomplete nerve-sparing technique.

Anatomic pathology of tumor cell spread through lymph nodes in the mesorectum of rectal cancer

AIM: To investigate the size, distribution, and pattern of metastases and micrometastases of lymph nodes (LNs) within the mesorectum of rectal cancer.

METHODS: All rectal cancer specimens obtained by total mesorectal excision were treated with lymph node revealing solution to retrieve all LNs, which were detected with a combination use of haematoxylin and eosin staining and immunohistochemical (IHC) staining with an antibody against cytokeratin 20.

RESULTS: A total of 548 LNs in 31 specimens were harvested, with 17.7 nodes per case. 153 nodes (27.9%) in 27 patients (87.1%) were found positive by routine pathological examination and IHC staining. Of all the nodes retrieved, nodes <0.5 cm numbered 366 (66.8%) with 91 (59.5%) positive. Among the 27 metastasized cases, there were 15 cases whose tumors were located in the back wall of the rectum, in which 78 nodes were detected positive with 75 nodes along the superior rectal artery. In the other 12 cases with tumors positioned in the lateral wall, 75 nodes were diagnosed positive, with 37 nodes, 8 nodes around the branch of superior rectal artery and middle rectal artery on tumor side, and 9 nodes, 0 nodes on the opposite side, respectively.

CONCLUSION: The majority of tumor positive LNs in the mesorectum are <0.5 cm in diameter. LNs within the mesorectum are distributed mainly along major supplying vessels with around the superior rectal artery most. The pattern of lymphatic spread of rectal cancer has close relationships with tumor location in the rectal wall. Tumors in the posterior wall may spread in both sides of the mesorectum simultaneously, while tumors localized in one lateral wall tend to metastasize preferably to LNs in the mesorectum of tumor side.