Residual urine volume after total mesorectal excision: an indicator of pelvic autonomic nerve preservation? Results of a case-control study

Prediction of urinary retention after surgery for rectal cancer using voiding efficiency in the 24 h following Foley catheter removal

PURPOSE

Postoperative urinary retention is a common adverse effect after rectal surgery. Current methods for assessing postoperative urinary retention (residual urine volume) are inaccurate and unable to predict long-term retention. Voiding efficiency is an effective indicator of postoperative urinary retention in urological and gynaecological fields, but not in colorectal surgery. We aimed to determine whether voiding efficiency in the initial 24 h after urinary catheter removal was more effective in predicting the incidence of postoperative urinary retention than residual urine volume.

METHODS

In this retrospective, observational study using prospectively collected data from patients who visited the colorectal department of a single institution, 549 patients who underwent rectal cancer surgery between April 2012 and May 2016 were initially enrolled, of which 46 were excluded and 503 finally included.

RESULTS

The incidence of postoperative urinary retention was 18.5% (93/503). Multivariable logistic regression analyses revealed that the association of postoperative urinary retention with voiding efficiency < 50% was stronger than that with residual urine volume > 100 mL (odds ratio, 38.30 (residual urine volume) and 138.0 (voiding efficiency)). Voiding efficiency was significantly lower in patients with long-term than in those with short-term postoperative urinary retention (adjusted p value = 0.02), whereas residual urine volume was not different between the two groups. Multivariable logistic regression analysis for long-term postoperative urinary retention showed the strongest association with voiding efficiency < 20% (odds ratio, 25.70).

CONCLUSIONS

Voiding efficiency is a more effective predictor of postoperative urinary retention than residual urine volume in rectal cancer patients.

Study protocol for a multicenter prospective controlled and randomized trial of transanal total mesorectal excision versus laparoscopic low anterior resection in rectal cancer

PURPOSE

Compared with the open approach, laparoscopic total mesorectal excision (TME) achieves faster patient recovery, reduces morbidity rates, and shortens hospital stay. However, in laparoscopic low anterior resection (L-LAR), conversion to open surgery is required in almost 20% of cases. Transanal TME (Ta-TME) combined with laparoscopy, also called hybrid natural orifice transluminal endoscopic surgery (NOTES), is a less invasive procedure that can overcome some of the limitations of laparoscopic rectal surgery. In this study, we aim to determine whether Ta-TME has a lower rate of conversion to open surgery than L-LAR, and thus achieves faster patient recovery without altering the pathological, functional, or oncological results. The main objective is to compare the results for conversion to open surgery between Ta-TME and L-LAR.

METHODS

Multicenter, prospective randomized controlled study of patients diagnosed with rectal adenocarcinoma who will be randomly allocated to Ta-TME or L-LAR groups after the application of inclusion and exclusion criteria. The main endpoint is conversion to open surgery and the secondary endpoints are general morbidity and mortality and hospital stay. Demographic, surgical, and pathological variables will also be studied, along with quality of life and survival. A sample size of 53 patients per group is calculated. With an estimated loss of 10%, the final sample required will be 116 patients.

CONCLUSIONS

Ta-TME achieves a lower conversion rate to open surgery than L-LAR, thus improving patient recovery and reducing overall morbidity.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02550769. Registration no. Ethical and Clinical Research Committee, Parc Taulí University Hospital: ID 2014/064.

Non-inferiority multicenter prospective randomized controlled study of rectal cancer T2-T3s (superficial) N0, M0 undergoing neoadjuvant treatment and local excision (TEM) vs total mesorectal excision (TME)

PURPOSE

The standard treatment of rectal adenocarcinoma is total mesorectal excision (TME), in many cases requires a temporary or permanent stoma. TME is associated with high morbidity and genitourinary alterations. Transanal endoscopic microsurgery (TEM) allows access to tumors up to 20 cm from the anal verge, achieves minimal postoperative morbidity and mortality rates, and does not require an ostomy. The treatment of T2, N0, and M0 cancers remains controversial. Preoperative chemoradiotherapy (CRT) in association with TEM reduces local recurrence and increases survival. The TAU-TEM study aims to demonstrate the non-inferiority of the oncological outcomes and the improvement in morbidity and quality of life achieved with TEM compared with TME.

METHODS

Prospective, multicenter, randomized controlled non-inferiority trial includes patients with rectal adenocarcinoma less than 10 cm from the anal verge and up to 4 cm in size, staged as T2 or T3-superficial N0-M0. Patients will be randomized to two areas: CRT plus TEM or radical surgery (TME). Postoperative morbidity and mortality will be recorded and patients will complete the quality of life questionnaires before the start of treatment, after CRT in the CRT/TEM arm, and 6 months after surgery in both arms. The estimated sample size for the study is 173 patients. Patients will attend follow-up controls for local and systemic relapse.

CONCLUSIONS

This study aims to demonstrate the preservation of the rectum after preoperative CRT and TEM in rectal cancer stages T2-3s, N0, M0 and to determine the ability of this strategy to avoid the need for radical surgery (TME).

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01308190. Número de registro del Comité de Etica e Investigación Clínica (CEIC) del Hospital universitario Parc Taulí: TAU-TEM-2009-01.

Urogenital dysfunctions after treatment of rectal cancer

A significant part of rectal cancer survivors will experience urogenital dysfunction induced by the treatment. Significant progress has been made in order to improve the total mesorectal technique through different approaches (open, laparoscopic, robotic, transanal). Rectal cancer surgery is technically difficult notably deep in the pelvis, and therefore the most frequent cause of the postoperative dysfunction is the surgical nerve damage of the autonomic nerves at this level. The main objectives of these efforts were to obtain maximal oncological results and to achieve better functional outcomes including less postoperative urogenital dysfunctions. Our purpose was to build a comprehensive review of the existing literature data regarding this issue from past to present.

Laparoscopic neuromapping in pelvic surgery: scopes of application

BACKGROUND

New developments in intraoperative electrophysiological neuromonitoring for conventional surgery are providing further insights into functional neuroanatomy and nerve-sparing in the minor pelvis. The aim of this study was to open up potential scopes of application in laparoscopy.

METHODS

Ten patients with different indications for surgery (presacral tumor excision, n = 2; resection rectopexy. n = 2; low anterior rectal resection, n = 2; proctocolectomy. n = 2; abdomino-perineal excision of the rectum, n = 2) were investigated prospectively. The pelvic autonomic nerves were bilaterally mapped by laparoscopic electric stimulation under simultaneous electromyography of the internal anal sphincter and manometry of the bladder. Stimulation results were compared to patients' anorectal and urogenital functional outcome.

RESULTS

In all the operations laparoscopic neuromapping (LNM) was technically feasible. Laparoscopy enabled excellent visibility of pelvic neural structures for simple and differentiated electric stimulation. In all cases LNM resulted in significantly evoked electromyographic potentials and intravesical pressure rises. The technique facilitated electrophysiological determination of functional neuroanatomical topography in the minor pelvis. The stimulation results were suitable to confirm laparoscopic nerve-sparing and compatible with patients' anorectal and urogenital functional outcome.

CONCLUSIONS

LNM is technically feasible and opens up a new dimension for verification of functional nerve integrity. Further developments and investigations are mandatory to evaluate its role for laparoscopic nerve-sparing procedures.

Predictors of postoperative urinary retention after colorectal surgery

BACKGROUND

National quality initiatives have mandated the earlier removal of urinary catheters after surgery to decrease urinary tract infection rates. A potential unintended consequence is an increased postoperative urinary retention rate.

OBJECTIVE

The aim of this study was to determine the incidence and risk factors for postoperative urinary retention after colorectal surgery.

DESIGN

This was a prospective observational study.

SETTINGS

A colorectal unit within a single institution was the setting for this study.

PATIENTS

Adults undergoing elective colorectal operations were included.

INTERVENTIONS

Urinary catheters were removed on postoperative day 1 for patients undergoing abdominal operations, and on day 3 for patients undergoing pelvic operations. Postvoid residual and retention volumes were measured.

MAIN OUTCOME MEASURES

The primary outcomes measured were urinary retention and urinary tract infection.

RESULTS

The overall urinary retention rate was 22.4% (22.8% in the abdominal group, 21.9% in the pelvic group) and was associated with longer operative time and increased perioperative fluid administration. Mean operative time for those with retention was 2.8 hours and, for those without retention, the mean operative time 2.2 hours (abdominal group 2 hours vs 1.4 hours, pelvic group 3.9 hours vs 3.1 hours, p ≤ 0.02). Patients with retention received a mean of 2.7L during the operation, whereas patients without retention received 1.8L (abdominal group 1.9L vs 1.4L, pelvic group 3.6L vs 2.2L, p < 0.01). In the abdominal group, patients with and without retention also received different fluid volumes on postoperative days 1 (2.2L vs 1.7L, p = 0.004) and 2 (1.6L vs 1L, p = 0.05). Laparoscopic abdominal group had a 40% retention rate in comparison with 12% in the open abdominal group (p = 0.004). Age, sex, preoperative radiation therapy, preoperative prostatism, preoperative diagnosis, and level of anastomosis were not associated with retention. The urinary tract infection rate was 4.9%.

LIMITATION

The lack of documentation of preoperative urinary function was a limitation of this study.

CONCLUSIONS

The practice of earlier urinary catheter removal must be balanced with operative time and fluid volume to avoid high urinary retention rates. Also important is increased vigilance for the early detection of retention.

Online signal processing of internal anal sphincter activity during pelvic autonomic nerve stimulation: a new method to improve the reliability of intra-operative neuromonitoring signals

AIM

Intra-operative neuromonitoring is increasingly applied in several surgical disciplines and has been introduced to facilitate pelvic autonomic nerve preservation. Nevertheless, it has been considered a questionable tool for the minimization of risk, as the results are variable and might be misleading. The aim of the present experimental study was to develop an intra-operative neuromonitoring system with improved reliability for monitoring pelvic autonomic nerve function.

METHOD

Fifteen pigs underwent low anterior rectal resection with pelvic autonomic nerve preservation. Intra-operative neuromonitoring was performed under autonomic nerve stimulation with observation of electromyographic signals of the internal anal sphincter and bladder manometry. As the internal anal sphincter frequency spectrum during stimulation was found to be mainly in the range of 5-20 Hz, intra-operative neuromonitoring signals were postoperatively processed by implementation of matching band pass filters.

RESULTS

In 10 preliminary experiments, signal processing was performed offline in the postoperative analysis. Of 163 stimulations intra-operatively assessed by the surgeon as positive responses, 135 (83%) were confirmed after signal processing. In the following five consecutive experiments intra-operative online signal processing was realized and demonstrated reliable intra-operative neuromonitoring signals of internal anal sphincter activity with significant increase during pelvic autonomic nerve stimulation [0.5 μV (interquartile range = 0.3-0.7) vs 4.8 μV (interquartile range = 2.5-7.5); P < 0.001].

CONCLUSION

Online signal processing of internal anal sphincter activity aids reliable identification of pelvic autonomic nerves with potential for improvement of intra-operative neuromonitoring in pelvic surgery.

Transanal endoscopic microsurgery for rectal cancer. Long-term oncologic results

PURPOSE

Local excision of malignant rectal tumors remains controversial due to the lack of prospective studies. The principal aim of this paper is to analyze survival and recurrence of patients with rectal cancer who were operated by transanal endoscopic microsurgery with curative intention.

METHODS

In 1997, we started a prospective protocol for patients who had T1/T2 rectal tumors: transanal local full-thickness excision was considered curative in T1 low risk (group A); patients with T1 high-risk and T2 low-risk tumors received postoperative radiotherapy (group B). From 1997 to 2006, 88 patients were enrolled. Sixty eight entered the study after the preoperative workup and 20 patients with an initial diagnosis of adenoma after postoperative definitive pathological assessment.

RESULTS

After definitive histological findings, 54 patients were to group A, 28 to group B, and 6 had immediate radical surgery. One patient was lost for follow-up. At a mean follow-up of 71 months, 7 (4 from group A and 3 from group B) out of 81 patients recurred. Five-year overall survival was of 94% and cancer-specific survival of 96%.

CONCLUSIONS

Our data support that transanal endoscopic microsurgery is an adequate treatment for T1 low-risk tumor, and no additional measures are required. For T2 low-risk lesions, our study showed a higher local recurrence rate than that reported after radical surgery but a similar survival outcome.

[Site of local surgery in adenocarcinoma of the rectum T2N0M0]

INTRODUCTION

The local exeresis adenocarcinoma of the rectum T(2)N(0)M(0) (ADC-T2), using transanal endoscopic microsurgery (TEM), has the benefit of achieving lower morbidity with a better quality of life. However, local occurrence of the local exeresis is greater than 20%, which is unacceptable these days.

PATIENTS AND METHODS

Prospective, observational follow up study. The tumours committee agreed that those ADC-T2 patients could have the following treatments: total mesorectal excision (TME), simple TEM, TEM with postoperative chemo- and radiotherapy (Ct-Rt), preoperative Ct-Rt with subsequent TEM and radical surgical rescue (TME) within at least 4 weeks.

RESULTS

Of the 146 patients operated on using TEM, 75 had adenocarcinomas, 59 adenomas, 6 scarring wounds, 5 carcinoids and 1 GIST. Of the adenocarcinomas 22 were ADC-T2. Follow up: median of 16 months (range, 3-32 months). The overall local recurrence was 18% (4/22). According to the treatment strategy the local occurrence was: TEM as the only procedure, 20% (2/10). Radical surgical rescue was performed on 3 patients after TEM, with no local or systemic recurrences. TEM with Qt-Rt after surgery was performed on 6 patients, with a local recurrence of 33% (2/6). Ct-Rt and subsequent TEM in 3 patients, with no local or systemic recurrences.

CONCLUSIONS

Treatment of ADC-T2 using simple TEM is not effective. The combination of Ct-Rt after TEM, does not improve the results of TME. It is possible to rescue those patients without changing the overall survival. Preoperative Ct-Rt and TEM appears to be the approach that obtains a clinical and histological response, although a response is needed by clinical trials.

Long-term follow-up of local rectal cancer surgery by transanal endoscopic microsurgery

BACKGROUND

In 1997 we launched a prospective program of transanal endoscopic microsurgery (TEM) for the treatment of rectal cancer.

METHODS

Suitability for TEM was based on endorectal ultrasound results, classified as follows: (I) benign tumors; (II) adenocarcinomas uT0 and uT1 with uN0; (III) adenocarcinomas uT2- uN0, low histological grade with intention to cure; and (IV) advanced stage adenocarcinomas with palliative care

RESULTS

Transanal endoscopic microsurgery was performed in 218 patients: 122 adenomas, and 96 adenocarcinomas: group II-72, group III-19, and group IV-5. Follow-up was >24 months (median 59 months) in 61 patients. Nine were lost to follow-up, and so 52 patients were studied: group II-38, group III-11, and group IV-3. The Kaplan-Meier probability of nonrecurrence of adenocarcinoma by group was 93% in tumors in situ (Tis) and T1; and 77.8% in T2. The Kaplan-Meier probability of survival by group was 100% in Tis and T1 and 82% in T2.

CONCLUSIONS

Rates of recurrence and long-term survival in Tis and T1 adenocarcinomas treated with TEM are similar to those in previously published reports using conventional surgery. Further studies are required in T2 adenocarcinomas to determine a definitive strategy.

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.

Successful voiding after trial without catheter is not synonymous with recovery of bladder function after colorectal surgery

PURPOSE

The need for monitoring postoperative urine output and the possibility of lower urinary tract dysfunction following colorectal surgery necessitates temporary urinary drainage. Current practice assumes recovery of lower urinary tract function to coincide with successful micturition after removal of urethral catheter. The aim of this study was to analyze the recovery of bladder function following colorectal surgery.

METHODS

Patients undergoing colorectal operations underwent preoperative and postoperative uroflowmetry and residual urine estimation. All patients were catheterized suprapubically at surgery. Uroflowmetry and postvoid residual volumes were recorded postoperatively until recovery of bladder function was complete.

RESULTS

Thirty consecutive patients underwent suprapubic catheterization, 25 of whom completed the study. Seventeen (68 percent) patients were able to pass urine within 72 hours of surgery. Recovery of lower urinary tract function was delayed in patients undergoing rectal vs. colonic resections (median, 6 vs. 3 days, P = 0.0015). Postvoid residual volumes greater than 200 ml were noted in three (20 percent) patients following rectal resections beyond the tenth postoperative day, with complete emptying achieved by six weeks.

CONCLUSIONS

Apparent successful micturition following rectal resections does not always indicate recovery of bladder function. The use of suprapubic catheters, in addition to being safe and effective, allows assessment of residual volumes postoperatively and smoothes the path to full recovery of lower urinary tract function.