Intraoperative parasympathetic nerve stimulation with tumescence monitoring 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.

Genito-urinary sequelae after carcinological rectal resection: What to tell patients in 2017

Although we have seen revolutionary changes with multi-disciplinary management of patients with rectal cancer, the evaluation of genito-urinary sequelae remains of great concern. Precise pre-operative evaluation with validated scores allows detection of urinary disorders in 16 to 23% of patients, and sexual disorders in nearly 35% of men and 50% of women. Regardless of the surgical approach, it is fundamental to respect the autonomic innervation during total mesorectal excision in order to prevent these sequelae. Identification of these nerves can be facilitated by intra-operative neuro-stimulation. In spite of these precautions, de novo urinary sequelae are observed in nearly 33% of patients and bladder evacuation disorders in 25% of patients. Advanced age, pre-operative urinary disorders, female gender, and abdomino-perineal resection are independent risk factors for urinary sequelae. Early post-operative urodynamic abnormalities might be predictive of these sequelae and justify early physiotherapy. Likewise, sexual sequelae such as erectile and/or ejaculatory disorders, dyspareunia and lubrication deficits result in de novo cessation of sexual activity in 28% of men and 18% of women. Advanced age, neo-adjuvant radiation therapy, and abdomino-perineal resection are independent risk factors for sexual dysfunction. Pharmacotherapy with sildenafil has proven useful in the treatment of erectile disorders. Genito-urinary and ano-rectal sequelae occur concomitantly in more than one of ten patients, suggesting a potential common pathophysiology.

Intraoperative monitoring of bladder and internal anal sphincter innervation: a predictor of erectile function following low anterior rectal resection for rectal cancer? Results of a prospective clinical study

BACKGROUND

The objective was to investigate whether two-dimensional intraoperative neuromonitoring (IONM) of pelvic autonomic nerves has the potential to predict erectile function (EF) following surgery for rectal cancer.

METHODS

A consecutive series of 17 sexually active male rectal cancer patients undergoing IONM-based nerve-sparing low anterior rectal resection were evaluated prospectively. IONM was performed by electric stimulation of the pelvic splanchnic nerves with concomitant electromyography of the internal anal sphincter and cystomanometry. Sexual function was assessed using a validated questionnaire.

RESULTS

The degree of agreement between electromyography-based and cystomanometry-based IONM with postoperative EF was moderate and good (κ = 0.43 and κ = 0.66). Combined assessment yielded the best agreement (κ = 0.76) with sensitivity of 90%, specificity of 86%, positive predictive value of 90%, negative predictive value of 86%, and overall accuracy of 88%, respectively, in terms of prediction of postoperative EF.

CONCLUSION

The method may be suitable to predict male EF following rectal resection.

Is intraoperative neuromonitoring associated with better functional outcome in patients undergoing open TME? Results of a case-control study

AIMS

Intraoperative neuromonitoring (IONM) aims to control nerve-sparing total mesorectal excision (TME) for rectal cancer in order to improve patients' functional outcome. This study was designed to compare the urogenital and anorectal functional outcome of TME with and without IONM of innervation to the bladder and the internal anal sphincter.

METHODS

A consecutive series of 150 patients with primary rectal cancer were analysed. Fifteen match pairs with open TME and combined urogenital and anorectal functional assessment at follow up were established identical regarding gender, tumour site, tumour stage, neoadjuvant radiotherapy and type of surgery. Urogenital and anorectal function was evaluated prospectively on the basis of self-administered standardized questionnaires, measurement of residual urine volume and longterm-catheterization rate.

RESULTS

Newly developed urinary dysfunction after surgery was reported by 1 of 15 patients in the IONM group and by 6 of 15 in the control group (p = 0.031). Postoperative residual urine volume was significantly higher in the control group. At follow up impaired anorectal function was present in 1 of 15 patients undergoing TME with IONM and in 6 of 15 without IONM (p = 0.031). The IONM group showed a trend towards a lower rate of sexual dysfunction after surgery.

CONCLUSIONS

In this study TME with IONM was associated with significant lower rates of urinary and anorectal dysfunction. Prospective randomized trials are mandatory to evaluate the definite role of IONM in rectal cancer surgery.

Evaluation of two-dimensional intraoperative neuromonitoring for predicting urinary and anorectal function after rectal cancer surgery

PURPOSE

The aim of this study was to compare the results of two-dimensional intraoperative neuromonitoring (IONM) with the postoperative urinary and anorectal function of rectal cancer patients.

METHODS

A consecutive series of 35 patients undergoing low anterior resection were investigated prospectively. IONM was performed with electric stimulations of the pelvic splanchnic nerves under simultaneous manometry of the bladder and electromyography (EMG) of the internal anal sphincter (IAS). Urinary and anorectal function were evaluated preoperatively and at follow-up by standardized questionnaires, digital rectal examination scoring system, and long-term catheterization rate.

RESULTS

The rate of postoperative newly developed bladder dysfunction was 17 %. IONM with bladder manometry had a sensitivity of 100 %, specificity of 96 %, positive predictive value of 83 %, negative predictive value of 100 %, and overall accuracy of 97 %, respectively. The proportion of patients with severely impaired anorectal function at follow-up was 8 %. The sensitivity, specificity, and positive and negative predictive values for IONM with EMG of the IAS were, respectively, 100, 96, 67, and 100 % with an accuracy of 96 %. The degree of agreement for IONM with EMG of the IAS was good for anorectal function (к = 0.780) and poor for urinary function (к = 0.119). IONM with bladder manometry yielded a very good degree of agreement for urinary function (к = 0.891) and a fair agreement for anorectal function (к = 0.336).

CONCLUSIONS

The two-dimensional IONM method is suitable for verification of bladder and IAS innervation. Accurate prediction of urinary and anorectal function necessitates both bladder manometry and EMG of the IAS.

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.

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.

Surgical treatment for colorectal cancer

The rapid in development of surgical technology has had a major effect in surgical treatment of colorectal cancer. Laparoscopic colon cancer surgery has been proven to provide better short-term clinical and oncologic outcomes. However this quickly accepted surgical approach is still performed by a minority of colorectal surgeons. The more technically challenging procedure of laparoscopic rectal cancer surgery is also on its way to demonstrating perhaps similar short-term benefits. This article reviews current evidences of both short-term and long-term outcomes of laparoscopic colorectal cancer surgery, including the overall costs comparison between laparoscopic surgery and conventional open surgery. In addition, different surgical techniques for laparoscopic colon and rectal cancer are compared. Also the relevant future challenge of colorectal cancer robotic surgery is reviewed.

Urinary and sexual disorders after laparoscopic TME for rectal cancer in males

BACKGROUND

Urinary and sexual dysfunctions are frequent after surgery for rectal cancer. Total mesorectal excision (TME) improves local recurrence and survival rates, and does not hamper recognition and sparing of hypogastric and pelvic splanchnic nerves. It is not known how laparoscopic rectal resection could change functional complication rates.

MATERIALS AND METHODS

From a global series of 1,216 laparoscopic interventions for colorectal diseases, 35 cases of males less than 70 years old, undergoing rectal resection and TME for a T1-3M0 medium and low rectal cancer were selected. Urinary and sexual functions after the operations were retrospectively recorded by means of specific tools (International Prostate Symptom Score (IPSS) and IIEF questionnaires, respectively).

RESULTS

None of the patients necessitated permanent or intermittent catheterization. More than half the patients had no complaints about urinary functions; about one third had nocturia; 72% of the patients had an IPSS less that 10, and no case of IPSS worse that 31 was recorded. Sexual desire was reduced and spontaneous erectile function was impaired in almost half the cases, while induced erections were possible in about 90% of cases; about 70% of patients still had the possibility of penetration and a normal ejaculation and orgasm after the intervention.

DISCUSSION AND CONCLUSIONS

The present series confirms previous data and contribute to the creation of a benchmark specifically related to the laparoscopic approach to which surgeons should face when informing the patients before the operation. While severe urinary dysfunction is rare, sexual impairment remains a serious concern after rectal resection with TME.

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.

Ileal pouch-anal anastomosis

BACKGROUND

Since 1977, restorative proctocolectomy with ileoanal anastomosis (IAA) has evolved into the surgical treatment of choice for most patients with intractable ulcerative colitis. Construction of an ileal pouch reservoir is now standard, usually in the form of J pouch (IPAA). The aim of this report is to review selection criteria for, and functional outcomes, follow-up and management of complications of IPAA after 30 years of widespread clinical application.

METHODS AND RESULTS

Literature published in English on the clinical indications, surgical technique, morbidity, complications and outcome following IAA and IPAA was sourced by electronic search, performed independently by two reviewers who selected potentially relevant papers based on title and abstract. Additional articles were identified by cross-referencing from papers retrieved in the initial search.

CONCLUSION

The functional results of IPAA are good. Pouchitis, irritable pouch syndrome and cuffitis are specific long-term complications but rarely result in failure. Pouch salvage is possible in selected patients with poor functional outcomes. One-stage operations are increasingly performed.

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.

Effects of transanal pelvic plexus stimulation on penile erection: clinical implications

OBJECTIVE

To determine the ability of transanal pelvic plexus stimulation (TPPS) in inducing penile tumescence in patients with non-neurogenic erectile dysfunction (ED) and to compare the erection degree with papaverine-induced erection.

PATIENTS AND METHODS

The cavernous electrical activity (CEA) in 21 men with non-neurogenic erectile dysfunction was measured during TPPS by electromyography of corpus cavernosum and the erection degree of penis (flaccid, semi-rigid, rigid) was noted. The stimulation amplitude was increased from 20 to 100 mA. All patients also underwent intracavernous papaverine injection and further CEA recordings were obtained.

RESULTS

Twelve and nine patients were diagnosed with vasculogenic (VED) and non-vasculogenic ED (NVED), respectively. TPSS led to a penile erectile response in 12 patients (57%), whereas papaverine injection caused erection in 16 (76.2%) patients. The mean baseline CEA (16.9 +/- 9.1 mV) did not change with TPPS, but papaverine significantly decreased the mean CEA to 12.3 +/- 4.9 mV (P < 0.001). CEA recordings of 16 (76.2%) patients revealed a significant decrease after papaverine injection, however seven (33.3%) patients showed significant CEA decrease in response to TPPS. Both TPPS and papaverine were observed to have a higher effect in patients with NVED in terms of inducing penile erection and decreasing CEA compared to their effects in patients with VED.

CONCLUSION

TPPS induces penile erection and decreases CEA for some extent, but to a lesser degree compared to papaverine. As further improvements are achieved in the methodology of TPPS, it may be a valuable method in the evaluation patients with erectile dysfunction.

Reconstruction of cavernous nerves by nerve grafts to restore potency: contemporary review of technical principles and basic anatomy

PURPOSE OF REVIEW

The review discusses the efficacy of reconstructing the neurovascular bundle to regain sexual function if nerve-sparing prostatectomy is unfeasible.

RECENT FINDINGS

Eleven studies could be found describing the reconstruction of neurovascular bundles. All reconstructive procedures displayed technical inadequacies. The effectiveness of unilateral neurovascular bundle reconstruction remains statistically insignificant when compared with procedures without reconstruction. The efficacy of reconstructing both neurovascular bundles ranges between 0 and 43%. Concerning basic anatomy, the neurovascular bundle contains fibers innervating the cavernous nerves, prostate, rectum, and levator ani muscle. The terms cavernous nerve and neurovascular bundle have often been wrongly considered synonymous. The pelvic splanchnic nerves probably do not join the neurovascular bundle proximal to the bladder/prostate junction but rather at variable distances from 10 to 20 mm distal to it. Therefore, described proximal coaptation sites at the bladder/prostate junction possibly encompass only the hypogastric nerve.

SUMMARY

Modest clinical results are partly due to inadequate surgical techniques and are mainly due to the anatomical and topographical complexity of the cavernous nerves. Contemporary nerve grafting techniques probably do not allow for the regeneration of all cavernous nerves.

Preservation of the Marginal Mandibular Branch of the Facial Nerve Using a Plexus Block Nerve Stimulator

Preserving the marginal mandibular branch of the facial nerve is essential in submandibular neck dissection to avert disfiguring complications. Despite the high incidence of postoperative palsy, old-fashioned techniques of nerve identification remain widespread. The use of disposable plexus block nerve stimulators as a safe and accurate method to localize the nerve intraoperatively is suggested herein. Such devices are significantly more affordable and user-friendly than larger facial nerve monitoring devices, which are rather favored for those procedures more extensively jeopardizing the branches of the facial nerve. In this report, disposable stimulators led to successful identification of the nerve in 100% of 25 patients between 2003 and 2005, with no postoperative paralysis. In addition, stimulation devices are constantly gaining in reliability and safety, and the number of surgical fields supporting their use is expanding. Therefore, their routine use for surgery on the submandibular area is recommended by the authors.

Modern management of rectal cancer: A 2006 update

The goal of this review is to outline some of the important surgical issues surrounding the management of patients with early (T1/T2 and N0), as well as locally advanced (T3/T4 and/or N1) rectal cancer. Surgery for rectal cancer continues to develop towards the ultimate goals of improved local control and overall survival, maintaining quality of life, and preserving sphincter, genitourinary, and sexual function. Information concerning the depth of tumor penetration through the rectal wall, lymph node involvement, and presence of distant metastatic disease is of crucial importance when planning a curative rectal cancer resection. Preoperative staging is used to determine the indication for neoadjuvant therapy as well as the indication for local excision versus radical cancer resection. Local excision is likely to be curative in most patients with a primary tumor which is limited to the submucosa (T1N0M0), without high-risk features and in the absence of metastatic disease. In appropriate patients, minimally invasive procedures, such as local excision, TEM, and laparoscopic resection allow for improved patient comfort, shorter hospital stays, and earlier return to preoperative activity level. Once the tumor invades the muscularis propria (T2), radical rectal resection in acceptable operative candidates is recommended. In patients with transmural and/or node positive disease (T3/T4 and/or N1) with no distant metastases, preoperative chemoradiation followed by radical resection according to the principles of TME has become widely accepted. During the planning and conduct of a radical operation for a locally advanced rectal cancer, a number of surgical management issues are considered, including: (1) total mesorectal excision (TME); (2) autonomic nerve preservation (ANP); (3) circumferential resection margin (CRM); (4) distal resection margin; (5) sphincter preservation and options for restoration of bowel continuity; (6) laparoscopic approaches; and (7) postoperative quality of life.

© 2006 The WJG Press. All rights reserved.

Surgical treatment of rectal cancer: radical resection

Currently, surgery is the only potentially curative treatment modality for rectal cancer. The major goals of surgery for rectal cancer are to optimize oncologic outcome and maintain anorectal and genitourinary function. This article reviews the surgical management of primary rectal cancer and discusses major surgical considerations in the treatment of this disease.

Recent neuroanatomical studies on the neurovascular bundle of the prostate and cavernosal nerves: clinical reflections on radical prostatectomy

The neurovascular bundle of the prostate and cavernosal nerves have been used to describe the same structure ever since the publication of the first studies on the neuroanatomy of the lower urogenital tract of men, studies that were prompted by postoperative complications arising from radical prostatectomy. In urological surgery every effort is made to preserve or restore the neurovascular bundle of the prostate to avoid erectile dysfunction (ED). However, the postoperative potency rates are yet to be satisfactory despite all advancements in radical prostatectomy technique. As the technology associated with urological surgery develops and topographical studies on neuroanatomy are cultivated, new observations seriously challenge the classical teachings on the topography of the neurovascular bundle of the prostate and the cavernosal nerves. The present review revisits the classical and most recent data on the topographical anatomy of the neurovascular bundle of the prostate and cavernosal nerves and their implications on radical prostatectomy techniques.

The efficacy of a nerve stimulator (Cavermap) to enhance autonomic nerve identification and confirm nerve preservation during total mesorectal excision

PURPOSE

Sexual dysfunction after total mesorectal excision may be caused by injury to the autonomic nerves. During surgery, nerve identification is not always achieved, and, to date, there has been no method to objectively confirm nerve preservation. The aim of this study was to assess the efficacy of a nerve-stimulating device (CaverMap) to assist in the intraoperative identification of the autonomic nerves during total mesorectal excision, and objectively confirm nerve preservation after proctectomy is completed.

PATIENTS AND METHODS

Sexually active consecutive male patients undergoing total mesorectal excision were prospectively enrolled in this study. During pelvic dissection, the surgeon attempted to localize the hypogastric and cavernous nerves. CaverMap was used to confirm these findings and to facilitate the identification in cases of uncertainty. At the completion of proctectomy, the nerves were restimulated to ensure preservation. Factors that could affect the surgeon's ability to localize the nerves and CaverMap to confirm this were evaluated.

RESULTS

Twenty-nine male patients with a median age of 58 years were enrolled in this study. An attempt to visualize the hypogastric nerves during dissection was made in 26 patients; the surgeon was able to identify the nerves in 19 (73 percent) patients. CaverMap successfully identified the nerves in six of the seven remaining patients, and failed to identify them in only one case. An attempt to localize the cavernous nerves during dissection was made in 13 patients, of which localization was successful in 8 (61.5 percent) patients. CaverMap improved the identification rate in four of the remaining five patients. After proctectomy, CaverMap successfully confirmed the preservation of both hypogastric and cavernous nerves in 27 of 29 (93 percent) patients. A history of previous surgery statistically correlated with failure to identify the hypogastric nerves by the surgeon (P = 0.005). There were no adverse events related to use of the device.

CONCLUSION

CaverMap may be a useful tool to facilitate identification of the pelvic autonomic nerves during total mesorectal excision and to objectively confirm nerve preservation.

Sacral neuromodulation in treatment of fecal incontinence following anterior resection and chemoradiation for rectal cancer

PURPOSE

Fecal incontinence may occur in patients who have undergone anterior resection for rectal cancer without presenting sphincter lesions. Chemoradiation may contribute to disrupting continence mechanisms. Treatment is controversial. Assessment of fecal incontinence in patients who agreed to integrate treatment for rectal cancer and treatment with sacral neuromodulation are reported.

METHODS

Fecal incontinence following preoperative chemoradiation and anterior resection for rectal cancer was evaluated in four patients. A good response was observed during the percutaneous sacral nerve evaluation test, and so permanent implant of sacral neuromodulation system was performed. Reevaluation was performed at least two months after implant.

RESULTS

After device implantation, the mean fecal incontinence scores decreased, and the mean number of incontinence episodes dropped from 12.0 to 2.5 per week (P < 0.05). Permanent implant resulted in a significant improvement in fecal continence in three patients, and incontinence was slightly reduced in the fourth. Manometric parameters agreed with clinical results: maximum and mean resting tone and the squeeze pressure were normal in three patients and reduced in one. In these same three patients, neorectal sensation parameters increased when the preoperative value was normal or below normal and decreased when the preoperative value was higher than normal, whereas in one patient in whom extremely low values were recorded all of the parameters decreased significantly.

CONCLUSIONS

Fecal incontinence following anterior resection and neoadjuvant therapy should be carefully evaluated. If a suspected neurogenic pathogenesis is confirmed, sacral neuromodulation may be proposed. If the test results are positive, permanent implant is advisable. Failure of this approach does not exclude the use of other, more aggressive treatment.

Validity of pelvic autonomic nerve stimulation with intraoperative monitoring of bladder function following total mesorectal excision for rectal cancer

PURPOSE

This prospective study was designed to clarify whether the results of the intraoperative stimulation of parasympathetic pelvic nerves performed in 31 patients after mesorectal excision for rectal carcinoma allowed predictions in terms of the postoperative bladder function of the patients.

METHODS

After monopolar stimulation of the splanchnic pelvic nerves using a constant voltage stimulator (Screener 3625), intravesical pressure increase was measured manometrically. The results were related to the postoperative residual urine volume, requirement of recatheterization and long-term catheterization, just as to the results of the validated International Prostatic Symptom Scores and the Quality of Life Index caused by urinary symptoms. The median follow-up period was nine (range, 2-14) months.

RESULTS

Parasympathetic nerve stimulation was performed at 61 sites and results in intravesical pressure increase up to 6 cm water column in median. In 11 patients (33.3 percent), a negative test result was achieved: 5 with unilateral and 6 with bilateral pressure increases of < or = 2 cm water column. Recatheterization was necessary in four patients, and all of them showed negative neuromonitoring results. Two of these patients were discharged with an in situ urinary bladder catheter. Postoperative increased residual urine volumes (> or =100 ml) resulted more frequently in the group with negative test results (63.6 vs. 21.1 percent; P = 0.047), and the International Prostatic Symptom Score and Quality of Life Index showed the worst results (9.9 +/- 6.7 vs. 3 +/- 4.9, P = 0.021; 2.4 +/- 1.7 vs. 0.7 +/- 1.3, P = 0.021).

CONCLUSIONS

Intraoperative neurostimulation and manometric measurement of bladder pressure may contribute to the identification of parasympathetic pelvic nerves during total mesorectal excision. This method is suitable for intraoperative recording of nerve preservation and therefore associated with postoperative bladder function.

Urinary and sexual function after total mesorectal excision

The autonomous pelvic nerves are in close contact to the visceral pelvic fascia that surrounds the mesorectum. The concept of total mesorectal excsion (TME) in rectal cancer treatment has led to a substantial improvement of autonomous pelvic nerve preservation. Consecutively, this highly precise and sharp dissection technique under direct vision reduces the problem of accidental bladder denervation from 50-60% with conventional rectal cancer surgery to less than 20% with TME and the problem of postoperative impotence from 70-100% to less than 30%. The learning curve in this technically demanding procedure plays a major role with regard to a satisfying nerve preservation. The laparoscopic approach for TME allows to obtain similarly favorable results with regard to postoperative urogenital function, at least for tumors situated in the middle and upper third of the rectum, compared with open surgery. The present paper describes and depictures in detail the anatomy and the pathophysiology of autonomic pelvic nerves, the surgical technique for nerve preservation and gives a short overview of the results in the literature including own data.

The efficacy of a nerve stimulator (CaverMap) to enhance autonomic nerve identification and confirm nerve preservation during total mesorectal excision

PURPOSE

Sexual dysfunction after total mesorectal excision may be caused by injury to the autonomic nerves. During surgery, nerve identification is not always achieved, and, to date, there has been no method to objectively confirm nerve preservation. The aim of this study was to assess the efficacy of a nerve-stimulating device (CaverMap) to assist in the intraoperative identification of the autonomic nerves during total mesorectal excision, and objectively confirm nerve preservation after proctectomy is completed.

PATIENTS AND METHODS

Sexually active consecutive male patients undergoing total mesorectal excision were prospectively enrolled in this study. During pelvic dissection, the surgeon attempted to localize the hypogastric and cavernous nerves. CaverMap was used to confirm these findings and to facilitate the identification in cases of uncertainty. At the completion of proctectomy, the nerves were restimulated to ensure preservation. Factors that could affect the surgeon's ability to localize the nerves and CaverMap to confirm this were evaluated.

RESULTS

Twenty-nine male patients with a median age of 58 years were enrolled in this study. An attempt to visualize the hypogastric nerves during dissection was made in 26 patients; the surgeon was able to identify the nerves in 19 (73 percent) patients. CaverMap successfully identified the nerves in six of the seven remaining patients, and failed to identify them in only one case. An attempt to localize the cavernous nerves during dissection was made in 13 patients, of which localization was successful in 8 (61.5 percent) patients. CaverMap improved the identification rate in four of the remaining five patients. After proctectomy, CaverMap successfully confirmed the preservation of both hypogastric and cavernous nerves in 27 of 29 (93 percent) patients. A history of previous surgery statistically correlated with failure to identify the hypogastric nerves by the surgeon (P = 0.005). There were no adverse events related to use of the device.

CONCLUSION

CaverMap may be a useful tool to facilitate identification of the pelvic autonomic nerves during total mesorectal excision and to objectively confirm nerve preservation.

Surgical Issues in Rectal Cancer: A 2004 Update

Rectal cancer is a major health concern in the United States, with an estimated 40,570 new cases diagnosed in 2004. There are 4 major goals in the treatment of a patient with rectal cancer: local control; long-term survival; preservation of anal sphincter, bladder, and sexual function; and maintenance or improvement in quality of life. Recent advances have been made in preoperative staging, local and radical surgical therapy, the importance of distal and circumferential resection margins, postoperative preservation of the anal sphincter mechanism and genitourinary function, and the role of laparoscopy in the treatment of these patients. Our aim is to outline some of the important surgical issues surrounding the management of patients with early-stage (T1/T2 N0) or locally advanced (T3/T4 and/or N1) rectal cancer.

Cavernosal nerve mapping: current data and applications

Although nerve-sparing prostatectomy is widely practised, the results with respect to preserving potency often do not meet expectations. The concept of intraoperative cavernosal nerve stimulation is reasonable. Data that link the response to sildenafil after prostatectomy with bilateral nerve sparing has increased the importance of optimizing nerve sparing. The cavernosal nerves are often difficult to visualize and may have a variable course. A tumescent response to nerve stimulation can be shown consistently; the response may be subtle, and characterized by a minimal increase in penile circumference and blood flow. Immediately after prostatectomy, proximal nerve stimulation identifies whether neural continuity has been maintained, and is predictive of recovery of erectile function. The Cavermap system (Uromed Corporation, Boston, MA, USA) was developed to permit intraoperative nerve stimulation with tumescence monitoring. An initial phase 2 and subsequent phase 3 single-blinded, randomized, multicentre study that compared Cavermap-assisted prostatectomy with conventional nerve sparing showed a significant benefit in terms of the duration of nocturnal tumescence at 1 year. Other approaches are being explored, including incorporating the device into sural or genito-femoral nerve grafting, use of nerve stimulation during cystectomy or abdominal-perineal resection, and direct corpus cavernosal pressure monitoring during nerve stimulation. These approaches warrant further evaluation.

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

BACKGROUND

Preservation of parasympathetic and sympathetic nerves is required to avoid urogenital function disturbances after total mesorectal excision (TME) for rectal carcinoma. This study sought to determine whether intraoperative stimulation of parasympathetic nerves with monitoring of bladder contraction is useful in meeting this demand.

STUDY DESIGN

In a prospective pilot study, 17 patients, 11 men and 6 women, underwent TME with pelvic autonomic nerve preservation performed by an experienced surgeon. The parasympathetic nerves were stimulated by an electrostimulation device (Screener 3625, Medronic), and the resulting bladder contraction was measured manometrically in all patients. Variations in pulse rate and voltage were measured to determine optimal stimulation parameters. A standardized questionnaire was used to record urogenital function disturbances. Residual urine volume was measured by ultrasound pre- and postoperatively. Shortterm outcomes data were evaluated to establish a possible association between intraoperative test results and postoperative bladder function.

RESULTS

In 15 of 17 patients undergoing TME with pelvic autonomic nerve preservation for rectal carcinoma, the parasympathetic nerves were identified based on nerve stimulation-induced bladder contraction. Two patients with negative results on intraoperative nerve stimulation had persisting bladder dysfunction requiring an indwelling catheter after discharge from hospital. In spite of a short median followup of 2 months (range 1 to 4 months), in 7 of 10 men with intact erectile function prior to surgery, postoperative erectile dysfunction could be excluded. The study showed a pulse rate of 35 Hz and an electric potential of 12 V to be optimal stimulation parameters, associated with a mean intravesical pressure rise of 12.7 cm H(2)O (range 2.8 to 18.0 cm H(2)O).

CONCLUSIONS

Intraoperative nerve stimulation with monitoring of intravesical pressure represents a technically simple procedure for the identification and verification of function of pelvic parasympathetic nerves during TME for rectal carcinoma.