Transanal endoscopic proctectomy and nerve injury risk: bottom to top surgical anatomy, key points

Short- and long-term impact of the TaTME learning process: a single institutional study

BACKGROUND

Transanal total mesorectal excision (TaTME) is a promising and innovative approach for lower rectal cancer but requires high technical skill and learning process that can affect patient outcomes. We aimed to determine the learning curve of TaTME and then to assess its impact on 5-year oncologic outcomes.

METHODS

Over a 54-month period, 94 patients underwent TaTME by experienced laparoscopic colorectal surgeons at our department. To provide a comprehensive overview of success, we used a composite criterion including the most relevant parameters related to the learning process: the conversion rate to an open procedure, TaTME procedure completion, severe postoperative morbidity, mesorectal integrity on macroscopic evaluation, and microscopic margins. Moving average method and cumulative sum analyses were performed.

RESULTS

The operative time continuously decreased over the entire study period. The success rate stabilised after 14 patients in a parallel and balanced analysis of the two surgeons' experiences. Mesorectal completeness was the most sensitive marker for the TaTME learning process (42.9% vs 71.25%; p = 0.06). The learning process did not significantly affect the postoperative morbidity, conversion rate, or R0 resection. Five-year oncological outcomes were similar between the groups.

CONCLUSION

Even among laparoscopically experienced surgeons, the TaTME learning process influences the oncological quality of the resection but not the postoperative morbidity. Gaining an early command of the surgical anatomy and technical skills and understanding the challenges through specific educational sessions are necessary. The results of this study could help generate a comprehensive training program and define necessary prerequisites for prospective trials.

TRIAL REGISTRATION

This study is registered in our Clinical Research Unit (2016_LELONG_01). Our database is registered in the clinicalTrials.gov registry: Institut Paoli Calmettes Colorectal Cancer Database (NCT02869503).

Initial experience with transanal proctectomy in children

BACKGROUND

The use of transanal proctectomy may have particular advantages for pediatric patients with small pelvic working space. We report short-term outcomes of transanal completion proctectomy (taCP) during surgery for inflammatory bowel disease.

METHODS

All patients (age≤19) underwent taCP from January 1, 2018 to December 31, 2019. Prior total abdominal colectomy (TAC) was performed using a single-incision technique. At operation, patients underwent single-incision laparoscopy with taCP. Patient demographics, pre and perioperative details, and postoperative complications were abstracted.

RESULTS

Seven patients (n = 6) with a median age of 18 years [Range: 13-19] were included in this initial series. All patients had a prior TAC with end-ileostomy with taCP occurring a median of 6 [Range: 3-89] months after TAC. Six of 7 had a diagnosis of ulcerative colitis (UC) while 1 patient had Crohn's colitis. For patients with UC, taCP was part of an ileal pouch-anal anastomosis with the majority (n = 4) proceeding as a modified-two stage and the remaining (n = 2) a three-stage approach. Single-incision laparoscopy through the prior ileostomy site was used in all IPAA patients. Median operative time was 226 [Range: 150-264] minutes with no conversions to more invasive technique. Median hospital length of stay (LOS) was 5 [Range: 2-8] days. In-hospital complications occurred in two patients who had watery diarrhea that prolonged LOS but resolved postdischarge. One patient was readmitted for bowel obstruction that resolved with placement of red rubber catheter at the ileostomy site. Of the 4 patients with a functioning ileal pouch, 1 patient reported 6-10 bowel movements per day, while 3 others reported ≤5 bowel movements per day. Half (n = 2) reported 1-2 nocturnal bowel movements at their first postoperative visit. No patients reported soiling or leakage, though one patient had a single episode of incontinence.

CONCLUSION

In this pilot series, transanal proctectomy was effective and safe. Future work should compare traditional MIS completion proctectomy to taCP for applications in pediatric inflammatory bowel disease.

TYPE OF STUDY

Case series.

LEVEL OF EVIDENCE

IV.

Re-exploring the pelvic neuroanatomy from a new perspective and a potential guidance for TaTME: a "bottom-up" approach

Neuro-anatomy of the perineum has gained renewed attention due to its significance in the transanal procedures for rectal cancer (eg TaTME). Surgeons embarking on this technique must have sophisticated knowledge and a precise anatomical understanding of the perineum before proceeding with this reversed rectal approach. We report anatomical observations deriving from a relevant experience in the colorectal surgery field. The collective multicenter experience of the present study is clinically relevant and based on the rectal and transanal resections performed in colorectal centers of excellence from Greece, UK, and Italy over the last 10 years (2011-2020). From the original anatomical and intraoperative observations derived from collective cases operated by this multicenter group of colorectal surgical centers in three European countries, data were retrieved and analyzed in collaboration with specialist researchers of human anatomy and interpreted for their clinical significance and potential use for preoperative planning and intraoperative guidance during TaTME. This descriptive article demonstrates in detail the neurogenic pathways encountered in the perineum and pelvic cavity during transanal procedures. Specific anatomical and topographic implications are also included serving as a guide for colorectal surgeons to perform a nerve-sparing procedure. transanal approach for rectal excision offers new insights into the complex pelvic and perineal neuroanatomy while the procedure itself remains a challenge for surgeons. Preoperative anatomical planning and 3D reconstruction may help in anticipating technical difficulties, resulting in more precise surgical dissections and decreased postoperative complications.

Evaluation of anatomical landmarks for transanal total mesorectal excision based on MRI

BACKGROUND

Transanal total mesorectal excision (taTME) is a novel sphincter-preserving procedure for low rectal cancer. This "bottom to up" approach is unfamiliar to colorectal surgeons and the crucial anatomical landmarks also remain unclear.

METHODS

Two hundred and five cases of pelvic magnetic resonance imaging (MRI) from 2015 to 2016 were reviewed. Curvature of posterior mesorectal fascia, distal mesorectal angle, length of posterior mesorectal fascia, main structures around the mesorectum were measured and analyzed. The landmarks identified on MRI were verified in taTME procedures of five rectal cancer patients.

RESULTS

The most of acute angles of posterior mesorectal fascia located at the joint of anococcygeal ligament-coccyx. Degree of distal mesorectal angle was independently correlated with gender and degree of angle of anococcygeal ligament-coccyx. Candidate landmarks evaluated by MRI with verification during taTME procedures included: anterior: seminal vesicle for male while cervix for female. And peritoneal reflection was a substitute landmark when cervix was hardly confirmed in operation; posterior: the joint of anococcygeal ligament-coccyx. The area between the joint of anococcygeal ligament-coccyx and S3S4 was a "transitional zone", the level of S3S4 could be the as the terminal landmark of transanal posterior dissection during taTME.

CONCLUSIONS

Preoperative MRI geometrical measurement of mesorectum might play an important role in evaluating the difficulty of taTME procedure before operation, as well as standardizing landmarks during taTME procedure.

MRI-based score to predict surgical difficulty in patients with rectal cancer

BACKGROUND

Rectal cancer surgery is technically challenging and depends on many factors. This study evaluated the ability of clinical and anatomical factors to predict surgical difficulty in total mesorectal excision.

METHODS

Consecutive patients who underwent total mesorectal excision for locally advanced rectal cancer in a laparoscopic, robotic or open procedure after neoadjuvant treatment, between 2005 and 2014, were included in this retrospective study. Preoperative clinical and MRI data were studied to develop a surgical difficulty grade.

RESULTS

In total, 164 patients with a median age of 61 (range 26-86) years were considered to be at low risk (143, 87·2 per cent) or high risk (21, 12·8 per cent) of surgical difficulty. In multivariable analysis, BMI at least 30 kg/m² (P = 0·021), coloanal anastomosis (versus colorectal) (P = 0·034), intertuberous distance less than 10·1 cm (P = 0·041) and mesorectal fat area exceeding 20·7 cm² (P = 0·051) were associated with greater surgical difficulty. A four-item score (ranging from 0 to 4), with each item (BMI, type of surgery, intertuberous distance and mesorectal fat area) scored 0 (absence) or 1 (presence), is proposed. Patients can be considered at high risk of a difficult or challenging operation if they have a score of 3 or more.

CONCLUSION

This simple morphometric score may assist surgical decision-making and comparative study by defining operative difficulty before surgery.

A multicentre randomised controlled trial to evaluate the efficacy, morbidity and functional outcome of endoscopic transanal proctectomy versus laparoscopic proctectomy for low-lying rectal cancer (ETAP-GRECCAR 11 TRIAL): rationale and design

BACKGROUND

Total mesorectal excision is the standard surgical treatment for mid- and low-rectal cancer. Laparoscopy represents a clear leap forward in the management of rectal cancer patients, offering significant improvements in post-operative measures such as pain, first bowel movement, and hospital length of stay. However, there are still some limits to its applications, especially in difficult cases. Such cases may entail either conversion to an open procedure or positive resection margins. Transanal endoscopic proctectomy (ETAP) was recently described and could address the difficulties of approaching the lower third of the rectum. Early series and case-control studies have shown favourable short-term results, such as a low conversion rate, reduced hospital length of stay and oncological outcomes comparable to laparoscopic surgery. The aim of the proposed study is to compare the rate of positive resection margins (R1 resection) with ETAP versus laparoscopic proctectomy (LAP), with patients randomly assigned to each arm.

METHODS/DESIGN

The proposed study is a multicentre randomised trial using two parallel groups to compare ETAP and LAP. Patients with T3 lower-third rectal adenocarcinomas for whom conservative surgery with manual coloanal anastomosis is planned will be recruited. Randomisation will be performed immediately prior to surgery after ensuring that the patient meets the inclusion criteria and completing the baseline functional and quality of life tests. The study is designed as a non-inferiority trial with a main criterion of R0/R1 resection. Secondary endpoints will include the conversion rate, the minimal invasiveness of the abdominal approach, postoperative morbidity, the length of hospital stay, mesorectal macroscopic assessment, functional urologic and sexual results, faecal continence, global quality of life, stoma-free survival, and disease-free survival at 3 years. The inclusion period will be 3 years, and every patient will be followed for 3 years. The number of patients needed is 226.

DISCUSSION

There is a strong need for optimal evaluation of the ETAP because of substancial changes in the operative technique. Assessment of oncological safety and septic risk, as well as digestive and urological functional results, is particularily mandatory. Moreover, benefits of the ETAP technique could be demonstrated  in post-operative outcome.

TRIAL REGISTRATION

ClinicalTrial.gov: NCT02584985 . Date and version identifier: Version n°2 - 2015 July 6.

Surgeons' assessment of internal anal sphincter nerve supply during TaTME - inbetween expectations and reality

Background: Intraoperative identification of nerve fibers heading from the inferior rectal plexus (IRP) to the internal anal sphincter (IAS) is challenging. The transanal total mesorectal excision (TaTME) is said to better preserve pelvic autonomic nerves. The aim of this study was to investigate the nerve identification rates during TaTME by transanal visual and electrophysiological assessment.

Material and methods: A total of 52 patients underwent TaTME for malignant conditions. The IRP with its posterior branches to the IAS and the pelvic splanchnic nerves (PSN) were visually assessed in 20 patients (v-TaTME). Electrophysiological nerve identification was performed in 32 patients using electric stimulation under processed electromyography of IAS (e-TaTME).

Results: The indication profile for TaTME was comparable between the v-TaTME and the e-TaTME group. The identification of IRP was more meaningful under electrophysiological assessment than under visual assessment for the left pelvic side (81% vs. 45%, p = 0.008) as well as the right pelvic side (78% vs. 45%, p = 0.016). The identification rates for PSN did not significantly differ between both groups, respectively (81% vs. 75%, p = 0.420 and 84% vs. 70%, p = 0.187).

Conclusions: The transanal approach facilitated visual identification of IAS nerve supply. In combination with electrophysiological nerve assessment the identification rate almost doubled. For further insights functional data are needed.

A systematic review of transanal total mesorectal excision: is this the future of rectal cancer surgery?

AIM

The surgical technique used for transanal total mesorectal excision (TaTME) was reviewed including the oncological quality of resection and the peri-operative outcome.

METHOD

A literature search of MEDLINE, Embase, Science Citation Index Expanded and Cochrane was performed in order to identify studies reporting on TaTME.

RESULTS

Thirty-six studies (eight case reports, 24 case series and four comparative studies) were identified, reporting 510 patients who underwent TaTME. The mean age ranged from 43 to 80 years and the mean body mass index from 21.7 to 31.8 kg/m(2) . The mean distance of the tumour from the anal verge ranged from 4 to 9.7 cm. The mean operation time ranged from 143 to 450 min and mean operative blood loss from 22 to 225 ml. The ratio of hand-sewn coloanal to stapled anastomoses performed was 2:1. One death was reported and the peri-operative morbidity rate was 35%. The anastomotic leakage rate was 6.1% and the reoperation rate was 3.7%. The mean hospital stay ranged from 4.3 to 16.6 days. The mesorectal excision was described as complete in 88% cases, nearly complete in 6% and incomplete in 6%. The circumferential resection margin was negative in 95% of cases and the distal resection margin was negative in 99.7%.

CONCLUSION

TaTME is a feasible and reproducible technique, with good quality of oncological resection. Standardization of the technique is required with formal training. Clear indications for this procedure need to be defined and its safety further assessed in future trials.

The quest for precision in transanal total mesorectal excision

Transanal total mesorectal excision (TME) is an emerging minimally invasive approach to rectal cancer, with encouraging preliminary results. However, the new surgical anatomy of the bottom-up approach complicates surgical understanding and increases the risks of inadvertent injuries to crucial anatomical structures, including nerves. Key elements to improve the safety and stimulate interest in such a complex technique might be robotics and image guidance, to enhance the level of precision. In this editorial, some of the technologies that could be used for precision TME are outlined, in light of the experience of our Institute for Image-Guided Surgery.

Transanal total mesorectal excision: Towards standardization of technique

AIM: To describe the role of Transanal total mesorectal excision (TaTME) in minimally invasive rectal cancer surgery, to examine the differences in patient selection and in reported surgical techniques and their impacts on postoperative outcomes and to discuss the future of TaTME.

METHODS: MEDLINE (PubMed), EMBASE, and The Cochrane Library were systematically searched through the 1^st of March 2015 using a predefined search strategy.

RESULTS: A total of 20 studies with 323 patients were included. Most studies were single-arm prospective studies with fewer than 100 patients. Multiple transanal access platforms were used, and the laparoscopic approach was either multi- or single port. The procedure was initiated transanally or transabdominally. If a simultaneous approach with 2 operating surgeons was chosen, the operative time was significantly reduced.

CONCLUSION: TaTME was also associated with better TME specimens and a longer distal resection margin. TaTME is thus feasible in expert hands, but the learning curve and safety profile are not well defined. Long-term follow-up regarding anal function and oncological outcomes should be performed in the future.

Transanal total mesorectal excision for rectal cancer: a preliminary report

BACKGROUND

Currently, the majority cases of the novel down-to-up transanal total mesorectal excision (TaTME) were performed in a hybrid approach with conventional laparoscopic assistance because of less operative difficulty. However, although cases are limited, the successes of TaTME in a pure approach (without laparoscopic assistance) indicate that the costly and less mini-invasive hybrid TaTME could be potentially avoided.

METHODS

In the present single institutional, prospective study, we attempted to demonstrate the safety and feasibility of this approach in rectal cancer by evaluating the short-term results of our first 20 TaTME cases. For the majority of cases, we adopted a strategy that laparoscopic assistance was not introduced unless it was required during the planned pure TaTME procedure.

RESULTS

A total of 20 patients (12 males and 8 females) were analyzed in this study, including 11 cases (55 %) of pure TaTME and 9 cases (45 %) of hybrid TaTME. Overall, the median operative time was 200 min (range 70-420), along with a median estimated blood loss of 50 ml (range 20-800). Morbidity rate was 20 % (one urethral injury, two urinary retentions, one anastomotic hemorrhage and one mild anastomotic leak). The median number of harvested lymph nodes was 12 (range 1-20). All specimens were intact in mesorectum without positive distal and circumferential resection margins. Among the 15 patients who were preoperatively scheduled to undertake pure TaTME, four patients (26.7 %) required converting to laparoscopic assistance. Moreover, among these 15 patients, the results of the comparative analysis between female and male subgroups favor the former, suggesting easier operation in them.

CONCLUSION

This preliminary study demonstrates that TaTME in rectal cancer is safe and feasible. The strategy of not introducing laparoscopic assistance unless it is required while performing the planned pTaTME should be cautiously explored. Further studies with larger sample size and longer follow-up are warranted.

The male bulbospongiosus muscle and its relation to the external anal sphincter

PURPOSE

The bulbospongiosus muscle is part of the superficial muscular layer of the perineum and pelvic floor. Its morphology remains controversial in the literature. Therefore, we reinvestigated the fascial arrangement and fiber courses of the bulbospongiosus muscle and its topographical relation to the external anal sphincter.

MATERIALS AND METHODS

The perineum was dissected in 9 male cadavers (mean ± SD age 78.3 ± 10.7 years). Select samples were obtained for histology and immunohistochemistry. In 43 patients (mean age 60.7 ± 12 years) the topographical relation between the bulbospongiosus muscle and the external anal sphincter was determined by magnetic resonance imaging.

RESULTS

The perineum contains several fascial layers consisting of elastic and collagen fibers as well as bundles of smooth muscle cells. The bulbospongiosus muscle was subdivided into a ventral and dorsal portion, which developed in 4 variants. The ventral insertion formed a morphological unity with the ischiocavernous muscle while the dorsal origin had a variable relation to the external anal sphincter (5 variants). A muscle-like or connective tissue-like connection was frequently present between the muscles. However, in some cases the muscles were completely separated.

CONCLUSIONS

We suggest a concept of variations of bulbospongiosus muscle morphology that unifies the conflicting literature. Its ventral fiber group and the ischiocavernosus muscle form a functional and morphological unity. While the bulbospongiosus muscle and the external anal sphincter remain independent muscles, their frequent connection might have clinical implications for perineal surgery and anogenital disorders.