Development and early outcomes of the national training initiative for transanal total mesorectal excision in the UK

IG-Net: An Instrument-guided real-time semantic segmentation framework for prostate dissection during surgery for low rectal cancer

BACKGROUND AND OBJECTIVE

Accurate prostate dissection is crucial in transanal surgery for patients with low rectal cancer. Improper dissection can lead to adverse events such as urethral injury, severely affecting the patient's postoperative recovery. However, unclear boundaries, irregular shape of the prostate, and obstructive factors such as smoke present significant challenges for surgeons.

METHODS

Our innovative contribution lies in the introduction of a novel video semantic segmentation framework, IG-Net, which incorporates prior surgical instrument features for real-time and precise prostate segmentation. Specifically, we designed an instrument-guided module that calculates the surgeon's region of attention based on instrument features, performs local segmentation, and integrates it with global segmentation to enhance performance. Additionally, we proposed a keyframe selection module that calculates the temporal correlations between consecutive frames based on instrument features. This module adaptively selects non-keyframe for feature fusion segmentation, reducing noise and optimizing speed.

RESULTS

To evaluate the performance of IG-Net, we constructed the most extensive dataset known to date, comprising 106 video clips and 6153 images. The experimental results reveal that this method achieves favorable performance, with 72.70% IoU, 82.02% Dice, and 35 FPS.

CONCLUSIONS

For the task of prostate segmentation based on surgical videos, our proposed IG-Net surpasses all previous methods across multiple metrics. IG-Net balances segmentation accuracy and speed, demonstrating strong robustness against adverse factors.

A novel step-by-step training program for transanal endoscopic surgery

BACKGROUND

The objective of our study is to develop an effective training platform for transanal endoscopic surgery and to validate a step-by-step training program for learning the basic skills necessary for this approach.

METHODS

We have designed a two-part study: an experimental study (with the aim to design the training platform and the training exercises - on synthetic and biological material) and a prospective analytical study, in order to validate the training program by enrolling as participants general surgery residents and specialists, without previous experience in transanal endoscopic interventions. The performance of the participants was assessed based on the time of completion, as well as the quality of the execution.

RESULTS

We have developed three different diameter platforms (5 cm, 7.5 and 10 cm), that can be used with both the TEO and TAMIS platforms; specific exercises were developed to train different surgical skills like manipulation of tissue, cutting, dissection and suturing. Forty participants were enrolled for the validation of the proposed training program (12 young residents, 16 senior residents and 12 specialist surgeons). A statistically significant improvement of the performance time, from round to round, was observed for all participants in all exercises. The time of completion for the exercises, considering the correct technical execution, was the shortest for more experienced surgeons: specialist surgeons, followed by senior residents and young residents. The biological material exercises, that closely recreate intraoperative conditions and had more strict technical requirements, were difficult to be performed by young residents; better completion rates were seen in senior residents, while all the participants in the specialist surgeons group have completed these exercises.

CONCLUSIONS

Our training program is an effective simulation based educational model for recreating intraoperative conditions particular to transanal endoscopic surgery. The proposed step-by-step training program has demonstrated to be useful in developing the important basic skills needed for transanal endoscopic surgery and assured the progress of all the participants, regardless of their surgical experience.

Surgical Outcomes, Long-Term Recurrence Rate, and Resource Utilization in a Prospective Cohort of 165 Patients Treated by Transanal Total Mesorectal Excision for Distal Rectal Cancer

A transanal total mesorectal excision (taTME) is a smart alternative to a conventional TME. However, worrisome reports of a high recurrence and complications triggered a moratorium in a few countries. This study assessed the outcomes and resource utilization of a taTME. Consecutive patients with distal rectal cancer treated by a taTME were prospectively included. Outcomes were reported as the median and interquartile range (IQR). One hundred sixty-five patients (67% male and 33% female) with a tumor 7 cm (IQR 5-10) from the anal verge were followed for 50 months (IQR 32-79). The resection margins were threatened in 25% of the patients, while 75% of the patients received neoadjuvant radiochemotherapy. A good mesorectal dissection and clear margins were achieved in 96% of the specimens, and 27 lymph nodes (IQR 20-38) were harvested. Ninety-day major morbidity affected 36 patients (21.8%), including 12 with anastomotic leakages (7.2%). A recurrence occurred locally in 9 patients (5.4%), and 44 patients had a distant metastasis (26.7%). The five-year disease-free survival and overall survival were 67% and 90%, respectively. A multivariate analysis found a long operation and frailty predicted an anastomotic leak, while a positive distal margin and lymph nodes predicted a local recurrence and distant metastasis. A two-team taTME saved 102 min of operative time and EUR 1385 when compared to a one-team approach. Transanal total mesorectal excision produced sound surgical quality and excellent oncologic outcomes.

Standardization of ileoanal J-pouch surgery technique: Quality assessment of minimally invasive ileoanal J-pouch surgery videos

BACKGROUND

Ileal pouch anal anastomosis is a complex procedure associated with significant morbidity, with several complications after ileal pouch anal anastomosis surgery leading to pouch failure. The aim of the study is to evaluate the heterogeneity surrounding the technique of ileoanal J-pouch surgery by assessing the safety and quality of published online peer-reviewed surgical videos.

METHODS

Ileal pouch anal anastomosis videos published on peer-reviewed surgical journals and video channels were edited and anonymized to demonstrate specific steps of the surgical procedure: mobilization and division of the rectum, formation of the ileoanal J-pouch reservoir, anastomosis, and lengthening techniques. The anonymized videos were presented to a group of reviewers with expertise in ileal pouch anal anastomosis blinded to the names and affiliations of the surgeons performing the procedure. Primary outcome was the rate of interobserver variability in the assessment of specific technical steps of the ileal pouch anal anastomosis surgery procedure. Secondary outcome was the appropriateness of the use of surgical videos review as an assessment tool for ileal pouch anal anastomosis surgery, measured as rate of reviewers being unable to answer for poor video quality.

RESULTS

In total, 29 video fragments were distributed, and 13 assessors completed a 60-item survey, organized in 7 major domains. The survey completion rate was 93.4%. Out of a total 729 answers, in 23 (3.2%) the reviewers indicated they were unable to comment due to poor video image, and in 48 (6.5%) were unable to comment due to the particular step not being shown in the procedure. The proportion of assessors rating rectal mobilization technically appropriate ranged from 30.7% to 92.3% and from 7.7% to 69.2% for safety. The level of rectal division was considered appropriate in 0 to 53.8% of the videos, whereas the stapling technique used for rectal division was appropriate in 0 to 70% of the videos.

CONCLUSION

Our study assessed published peer-reviewed videos on ileal pouch anal anastomosis surgery and reported heterogeneity in the safety of the demonstrated techniques. Blind assessment of published peer-reviewed ileal pouch anal anastomosis videos reported a high rate of unsafe or inappropriate technique for rectal mobilization and transection in the reviewed videos, with fair interobserver agreement among reviewers. There is a need for consensus on what is considered safe and appropriate in ileal pouch anal anastomosis surgery. Peer review of ileal pouch anal anastomosis surgery videos could facilitate training and accreditation in this complex procedure.

Defining the learning curve of transanal total mesorectal excision: a systematic review and meta-analysis

BACKGROUND

Transanal total mesorectal excision (taTME) represents a novel approach to rectal dissection. Although many structured training programs have been developed worldwide to assist surgeons in implementing this new technique, the learning curve (LC) of taTME has yet to be conclusively defined. This is particularly important given the concerns regarding the complication profile and oncological safety of taTME. The aim of this review was to provide an up-to-date systematic review and meta-analysis of the LC for taTME, comparing the difference of outcomes between the LC and after learning curve (ALC) groups.

METHODS

An up-to-date systematic review was performed on the available literature between 2010-2020 on PubMed, EMBASE, Medline and Cochrane Library databases. All studies comparing taTME procedures before and after LC were analysed.

RESULTS

Seven retrospective studies of prospectively collected databases were included, comparing 333 (51.0%) patients in the LC group and 320 (49.0%) patients in the ALC group. There was a significantly reduced number of adverse intra-operative events, anastomotic leaks and improved quality of mesorectal excision in the ALC group.

CONCLUSION

This review shows that there is a significant improvement in clinical outcomes between the LC and ALC groups which supports the need for careful mastery and ongoing technical refinement during the LC in taTME. This procedure should be performed on a subset of carefully selected patients in the hands of experienced and well-trained teams dedicated to ongoing audit.

Systematic review of transanal total mesorectal excision literature according to the ideal framework: The evolution never ends

BACKGROUND

Designing studies to assess critically novel procedures can be challenging; thus, the process to achieve robust evidence is frequently problematic. The aim of this systematic review was to evaluate if literature on transanal total mesorectal excision is evolving according to the Idea, Development, Exploration, Assessment, and Long-term results framework.

METHODS

Literature on transanal total mesorectal excision was searched according to the preferred reporting items for systematic reviews and meta-analyses statement, and these variables were recorded: bibliometric data, design, corresponding author's nationality, number of patients enrolled, and Idea, Development, Exploration, Assessment, and Long-term results stages (stage 0, stage 1, stage 2, stage 3, and stage 4).

RESULTS

Out of 447 articles retrieved, 247 were selected (76.5% single center and 23.5% multicenter collaborations), including 35 reviews, 15 meta-analyses, 24 other publications, and 173 articles classified according to Idea, Development, Exploration, Assessment, and Long-term results stages (19 stage 0, 27 stage 1, 111 stage 2, 7 stage 3, and 9 stage 4). Overall, impact factor produced was 634.10. Reviewing corresponding authors' nationalities, 32 countries were identified, with the United States, China, and the United Kingdom the most reported; nearly all were from the Northern Hemisphere. Publication of stage 3 and 4 articles started in 2014, whereas stage 0 and 1 articles were stably published over time. The number of patients increased in correspondence with the Idea, Development, Exploration, Assessment, and Long-term results stages (case series with >51 patients, respectively, 100.0% stage 3, 77.8% stage 4, and 33.3% stage 2, P = .005).

CONCLUSION

The number of stage 3 and 4 articles is still low; however, the technical innovation of transanal total mesorectal excision is a non-stop process with preclinical studies stably published over time.

The learning curve of transanal total mesorectal excision for rectal cancer is associated with local recurrence: results from a multicentre external audit

AIM

Transanal total mesorectal excision (TaTME) has been suggested as a potential solution for the resection of challenging mid and low rectal cancer. This relatively complex procedure has been implemented in many centres over the last years, despite the absence of long-term safety data. Recently, concern has arisen because of an increase in local recurrence in the implementation phase. The aim of this study was to assess the correlation between accumulated experience and local recurrences.

METHOD

An independent clinical researcher performed an external audit of consecutive series of all TaTME procedures in six centres in the Netherlands. Kaplan-Meier estimated local recurrence rates were calculated and multivariate Cox proportional hazards regression analysis performed to assess risk factors for local recurrence. Primary outcome was the local recurrence rate in the initial implementation (cases 1-10), continued adoption (cases 11-40) and prolonged experience (case 41 onward).

RESULTS

Six hundred and twenty-four consecutive patients underwent TaTME for rectal cancer with a median follow-up of 27 months (range 1-82 months). The estimated 2- and 3-year local recurrence rates were 4.6% and 6.6%, respectively. Cox proportional hazards regression revealed procedural experience to be an independent factor in multivariate analysis next to advanced stage (ycMRF+, pT3-4, pN+) and pelvic sepsis. Corrected analysis projected the 3-year local recurrence rates to be 9.7%, 3.3% and 3.5% for the implementation, continued adoption and prolonged experience cohorts, respectively.

CONCLUSION

This multicentre study shows a high local recurrence rate (12.5%) after implementation of TaTME which lowers to an acceptable rate (3.4%) when experience increases. Therefore, intensified proctoring and further precautions must be implemented to reduce the unacceptably high risk of local recurrence at units starting this technique.

Short-term outcomes after transanal total mesorectal excision for rectal cancer in Denmark - a prospective multicentre study

AIM

The aim of this study was to evaluate the short-term surgical and oncological outcomes after transanal total mesorectal excision (TaTME) for rectal cancer during the implementation phase of this procedure in Denmark.

METHOD

This is a retrospective review of prospectively recorded data. Registration was initiated by the Scientific Council of the Danish Colorectal Cancer Group (DCCG.dk) in order to assess the quality of care during the implementation of TaTME. Pre-, intra- and postoperative data including early recurrences were recorded at the operating centres.

RESULTS

From August 2016 to April 2019, 115 TaTME procedures were registered. Patients were predominantly male (74%) with mid-rectal (88%) tumours. The level of surgical complications was comparable to previous nationwide results. Anastomotic leakage occurred in 6/109 (5.5%). One urethral injury occurred. The plane of dissection was mesorectal in 60% of cases, intramesorectal in 28% and muscularis in 12%. Nonmicroradicality was seen in 8% (R1, 6%; R2, 2%). Four local recurrences occurred after a median of 23 months of follow-up. One of these was multifocal.

CONCLUSION

In an implementation phase where patient selection is expected, surgical and oncological results after TaTME were comparable to those of other approaches reported in the literature.

Surgical approach for rectal cancer: A network meta-analysis comparing open, laparoscopic, robotic and transanal TME approaches

BACKGROUND

The optimal approach for total mesorectal excision (TME) of rectal cancer remains controversial.

AIM

To compare short- and long-term outcomes after open (OpTME), laparoscopic (LapTME), robotic (RoTME) and transanal TME (TaTME).

METHODS

A systematic search of electronic databases was performed up to January 1, 2020 for randomized controlled trials (RCTs) comparing at least 2 TME strategies. A Bayesian arm-based random effect network meta-analysis (NMA) was performed, specifically, a mixed treatment comparison (MTC).

RESULTS

30 RCTs (and six updates) of 5586 patients with rectal cancer were included. No significant differences were identified in recurrence rates or survival rates. Operating time was shorter with OpTME (surface under the cumulative ranking curve [SUCRA] 0.96) compared to LapTME, RoTME and TaTME. Although OpTME was associated with the most blood loss (SUCRA 0.90) and had a slower recovery with increased length of stay (SUCRA 0.90) compared to the minimally invasive techniques, there was no difference in postoperative morbidity. OpTME was associated with a more complete TME specimen compared to LapTME (Risk Ratio [RR] 1.05, 95% Credible Interval [CrI] 1.01, 1.11), and TaTME had less involved CRMs (RR 0.173, 95% CrI 0.02, 0.76) versus LapTME. There were no differences between the modalities in terms of deep TME defects, DRM distance, or lymph node yield.

CONCLUSIONS

While OpTME was the most effective TME modality for short term histopathological resection quality, there was no difference in long-term oncologic outcomes. Minimally invasive approaches enhance postoperative recovery, at the cost of longer operating times. Technique selection should be based on individual tumour characteristics and patient expectations, as well as surgeon and institutional expertise.