Robotic Transanal Minimally Invasive Surgery for Rectal Polyps.

Transanal minimally invasive surgery (TAMIS) can be utilized to manage a wide variety of rectal lesions but can be technically demanding with traditional laparoscopic equipment. Robotic platforms such as the da Vinci Single Port system can reduce the technical barriers of TAMIS and allow more complicated lesions to be addressed. Robotic TAMIS with the SP system follows similar indications for local excision of benign and malignant lesions as conventional TAMIS or even transanal endoscopic microsurgery. We describe our initial experience using the SP system and provide technical suggestions for how to incorporate this technology. We also address innovations in flexible endoscopic robotic surgery that we anticipate will allow for increased use of organ preservation of the colon and rectum, as well as possibly expand the use of natural orifice surgery.

Trans­anal minimally invasive surgery (TAMIS) versus rigid platforms for local excision of early rectal cancer: a systematic review and meta-analysis of the literature.

BACKGROUND: Available platforms for local excision (LE) of early rectal cancer are rigid or flexible [trans­anal minimally invasive surgery (TAMIS)]. We systematically searched the literature to compare outcomes between platforms. METHODS: PRISMA-compliant search of PubMed and Scopus databases until September 2022 was undertaken in this random-effect meta-analysis. Statistical heterogeneity was assessed using I2 statistic. Studies comparing TAMIS versus rigid platforms for LE for early rectal cancer were included. Main outcome measures were intraoperative and short-term postoperative outcomes and specimen quality. RESULTS: 7 studies were published between 2015 and 2022, including 931 patients (423 females); 402 underwent TAMIS and 529 underwent LE with rigid platforms. Techniques were similar for operative time (WMD 11.1, 95%CI - 2.6 to 25, p = 0.11), percentage of defect closure (OR 0.7, 95%CI 0.06-8.22, p = 0.78), and peritoneal violation (OR 0.41, 95%CI 0.12-1.43, p = 0.16). Rigid platforms had higher rates of short-term complications (19.1% vs 14.2, OR 1.6, 95%CI 1.07-2.4, p = 0.02), although no significant differences were seen for major complications (OR 1.41, 95%CI 0.61-3.23, p = 0.41). Patients in the rigid platforms group were 3-times more likely to be re-admitted within 30 days compared to the TAMIS group (OR 3.1, 95%CI 1.07-9.4, p = 0.03). Rates of positive resection margins (rigid platforms: 7.6% vs TAMIS: 9.34%, OR 0.81, 95%CI 0.42-1.55, p = 0.53) and specimen fragmentation (rigid platforms: 3.3% vs TAMIS: 4.4%, OR 0.74, 95%CI 0.33-1.64, p = 0.46) were similar between the groups. Salvage surgery was required in 5.5% of rigid platform patients and 6.2% of TAMIS patients (OR 0.8, 95%CI 0.4-1.8, p = 0.7). CONCLUSION: TAMIS or rigid platforms for LE seem to have similar operative outcomes and specimen quality. The TAMIS group demonstrated lower readmission and overall complication rates but did not significantly differ for major complications. The choice of platform should be based on availability, cost, and surgeon's preference.

Artificial intelligence-assisted decision making: Prediction of optimal level of distal mesorectal margin during transanal total mesorectal excision (taTME) using deep neural network modeling.

BACKGROUND: With steep posterior anorectal angulation, transanal total mesorectal excision (taTME) may have a risk of dissection in the wrong plane or starting higher up, resulting in leaving distal mesorectum behind. Although the distal mesorectal margin can be assessed by preoperative MRI, it needs skilled radiologist and high-definition image for accurate evaluation. This study developed a deep neural network (DNN) to predict the optimal level of distal mesorectal margin. METHODS: A total of 182 pelvic MRI images extracted from the cancer image archive (TCIA) database were included. A DNN was developed using gender, the degree of anterior and posterior anorectal angles as input variables while the difference between anterior and posterior mesorectal distances from anal verge was selected as a target. The predictability power was assessed by regression values (R) which is the correlation between the predicted outputs and actual targets. RESULTS: The anterior angle was an obtuse angle while the posterior angle varied from acute to obtuse with mean angle difference 35.5°±14.6. The mean difference between the anterior and posterior mesorectal end distances was 18.6±6.6mm. The developed DNN had a very close correlation with the target during training, validation, and testing (R=0.99, 0.81, and 0.89, P<0.001). The predicted level of distal mesorectal margin was closely correlated with the actual optimal level (R=0.91, P<0.001). CONCLUSIONS: Artificial intelligence can assist in either making or confirming the preoperative decisions. Furthermore, the developed model can alert the surgeons for this potential risk and the necessity of re-positioning the proctectomy incision.

Solitary fibrous tumor within the mesorectum: literature review based on a case report of resection by transanal minimally invasive surgery (TAMIS).

PURPOSE: Solitary fibrous tumors (SFT) are a rare entity of in majority benign neoplasms. Nevertheless, up to 20% of cases show a malignant tendency with local infiltration or metastasis. Commonly arising in the thoracic cavity, only few cases of SFT of the mesorectal tissue have been reported in the literature. Complete surgical resection, classically by posterior approach, is the treatment of choice. The purpose of this review is to demonstrate the safety and suitability of transanal minimally invasive surgery (TAMIS) as a surgical approach for the resection of benign pararectal solid tumors. METHODS: We report the case of a 52-year-old man who was diagnosed incidentally with SFT of the distal mesorectum. Resection by TAMIS was performed. Based on this case, we describe the steps and potential benefits of this procedure and provide a comprehensive review of the literature. RESULTS: Histopathology confirms the completely resected SFT. After uneventful postoperative course and discharge on day four, follow-up was recommended by a multidisciplinary board by clinical examination and MRI, which showed a well-healed scar and no recurrence up to 3 years after resection. CONCLUSION: SFT of the mesorectum is a very rare entity. To our knowledge, this is the first report on a TAMIS resection for SFT, demonstrated as a safe approach for complete resection of benign pararectal solid tumors.

Minimally invasive approach for retrorectal tumors above and below S3: a multicentric tertiary center retrospective study (MiaRT study).

BACKGROUND: Retrorectal tumors are uncommon lesions developed in the retrorectal space. Data on their minimally invasive resection are scarce and the optimal surgical approach for tumors below S3 remains debated. METHODS: We performed a retrospective review of consecutive patients who underwent minimally invasive resection of retrorectal tumors between 2005 and 2022 at two tertiary university hospital centers, by comparing the results obtained for lesions located above or below S3. RESULTS: Of over 41 patients identified with retrorectal tumors, surgical approach was minimally invasive for 23 patients, with laparoscopy alone in 19, with transanal excision in 2, and with combined approach in 2. Retrorectal tumor was above S3 in 11 patients (> S3 group) and below S3 in 12 patients (< S3 group). Patient characteristics and median tumor size were not significantly different between the two groups (60 vs 67 mm; p = 0.975). Overall median operative time was 131.5 min and conversion rate was 13% without significant difference between the two groups (126 vs 197 min and 18% vs 8%, respectively; p > 0.05). Final pathology was tailgut cyst (48%), schwannoma (22%), neural origin tumor (17%), gastrointestinal stromal tumor (4%), and other (19%). The 90-day complication rates were 27% and 58% in the > S3 and < S3 groups, respectively, without severe morbidity or mortality. After a median follow-up of 3.3 years, no recurrence was observed in both groups. Three patients presented chronic pain, three anal dysfunction, and three urinary dysfunction. All were successfully managed without reintervention. CONCLUSIONS: Minimally invasive surgery for retrorectal tumors can be performed safely and effectively with low morbidity and no mortality. Laparoscopic and transanal techniques alone or in combination may be recommended as the treatment of choice of benign retrorectal tumors, even for lesions below S3, in centers experienced with minimally invasive surgery.

Surgeon assessment of significant rectal polyps using white light endoscopy alone and in comparison to fluorescence-augmented AI lesion classification.

PURPOSE: Perioperative decision making for large (> 2 cm) rectal polyps with ambiguous features is complex. The most common intraprocedural assessment is clinician judgement alone while radiological and endoscopic biopsy can provide periprocedural detail. Fluorescence-augmented machine learning (FA-ML) methods may optimise local treatment strategy. METHODS: Surgeons of varying grades, all performing colonoscopies independently, were asked to visually judge endoscopic videos of large benign and early-stage malignant (potentially suitable for local excision) rectal lesions on an interactive video platform (Mindstamp) with results compared with and between final pathology, radiology and a novel FA-ML classifier. Statistical analyses of data used Fleiss Multi-rater Kappa scoring, Spearman Coefficient and Frequency tables. RESULTS: Thirty-two surgeons judged 14 ambiguous polyp videos (7 benign, 7 malignant). In all cancers, initial endoscopic biopsy had yielded false-negative results. Five of each lesion type had had a pre-excision MRI with a 60% false-positive malignancy prediction in benign lesions and a 60% over-staging and 40% equivocal rate in cancers. Average clinical visual cancer judgement accuracy was 49% (with only 'fair' inter-rater agreement), many reporting uncertainty and higher reported decision confidence did not correspond to higher accuracy. This compared to 86% ML accuracy. Size was misjudged visually by a mean of 20% with polyp size underestimated in 4/6 and overestimated in 2/6. Subjective narratives regarding decision-making requested for 7/14 lesions revealed wide rationale variation between participants. CONCLUSION: Current available clinical means of ambiguous rectal lesion assessment is suboptimal with wide inter-observer variation. Fluorescence based AI augmentation may advance this field via objective, explainable ML methods.

Robotic transanal minimally invasive surgery (R-TAMIS): current evidence in the treatment of early rectal neoplasia.

INTRODUCTION: Robotic transanal minimally invasive surgery (R-TAMIS) was introduced in 2012 for the excision of benign rectal polyps and low grade rectal cancer. Ergonomic improvements over traditional laparoscopic TAMIS (L-TAMIS) include increased dexterity within a small operative field, with possibility of better surgical precision. We aim to collate the existing data surrounding the use of R-TAMIS to treat rectal neoplasms from cohort studies and larger case series, providing a foundation for future, large-scale, comparative studies. METHODS: Medline, EMBASE and Web of Science were searched as part of our review. Randomised controlled trials (RCTs), cohort studies or large case series (≥ 5 patients) investigating the use of R-TAMIS to resect rectal neoplasia (benign or malignant) were eligible for inclusion in our analysis. Quality assessment of included studies was performed via the Newcastle Ottawa Scale (NOS) risk of bias tool. Outcomes extracted included basic participant characteristics, operative details and histopathological/oncological outcomes. RESULTS: Eighteen studies on 317 participants were included in our analysis. The quality of studies was generally satisfactory. Overall complication rate from R-TAMIS was 9.7%. Clear margins (R0) were reported in 96.2% of patients. Local recurrence (benign or malignant) occurred in 2.2% of patients during the specified follow-up periods. CONCLUSION: Our review highlights the current evidence for R-TAMIS in the local excision of rectal lesions. While R-TAMIS appears to have complication, margin negativity and recurrence rates superior to those of published L-TAMIS series, comparative studies are needed.

Robotic transanal minimally invasive surgery (r-TAMIS): perioperative and short-term outcomes for local excision of rectal cancers.

BACKGROUND: Transanal minimally invasive surgery (TAMIS) is an advanced technique for excision of early rectal cancers. Robotic TAMIS (r-TAMIS) has been introduced as technical improvement and potential alternative to total mesorectal excision (TME) in early rectal cancers and in frail patients. This study reports the perioperative and short-term oncological outcomes of r-TAMIS for local excision of early-stage rectal cancers. METHODS: Retrospective analysis of a prospectively collected r-TAMIS database (July 2021-July 2023). Demographics, clinicopathological features, short-term outcomes, recurrences, and survival were investigated. RESULTS: Twenty patients were included. Median age and body mass index were 69.5 (62.0-77.7) years and 31.0 (21.0-36.5) kg/m2. Male sex was prevalent (n = 12, 60.0%). ASA III accounted for 66.7%. Median distance from anal verge was 7.5 (5.0-11.7) cm. Median operation time was 90.0 (60.0-112.5) minutes. Blood loss was minimal. There were no conversions. Median postoperative stay was 2.0 (1.0-3.0) days. Minor and major complication rates were 25.0% and 0%, respectively. Seventeen (85.0%) patients had an adenocarcinoma whilst three patients had an adenoma. R0 rate was 90.0%. Most tumours were pT1 (55.0%), followed by pT2 (25.0%). One patient (5.0%) had a pT3 tumour. Specimen and tumour maximal median diameter were 51.0 (41.0-62.0) mm and 21.5 (17.2-42.0) mm, respectively. Median specimen area was 193.1 (134.3-323.3) cm2. Median follow-up was 15.5 (10.0-24.0) months. One patient developed local recurrence (5.0%). CONCLUSIONS: r-TAMIS, with strict postoperative surveillance, is a safe and feasible approach for local excision of early rectal cancer and may have a role in surgically unfit and elderly patients who refuse or cannot undergo TME surgery. Future prospective multicentre large-scale studies are needed to report the long-term oncological outcomes.

Transanal minimally invasive surgery (TAMIS) for local excision of benign and malignant rectal neoplasia: a 7-year experience.

PURPOSE: Transanal minimally invasive surgery (TAMIS) is an advanced transanal platform that can be utilised to perform high-quality local excision (LE) of rectal neoplasia. This study describes clinical and midterm oncological outcomes from a single unit's 7-year experience with TAMIS. METHODS: Consecutive patients who underwent TAMIS LE at our institution between January 1st, 2016, and December 31st, 2022, were identified from a prospectively maintained database. Indication for TAMIS LE was benign lesions not amenable to endoscopic excision or histologically favourable early rectal cancers. The primary endpoints were resection quality, disease recurrence and peri-operative outcomes. The Kaplan-Meier survival analyses were used to describe disease-free survival (DFS) for patients with rectal adenocarcinoma that did not receive immediate salvage proctectomy. RESULTS: There were 168 elective TAMIS LE procedures performed for 102 benign and 66 malignant lesions. Overall, a 95.2% negative margin rate was observed, and 96.4% of lesions were submitted without fragmentation. Post-operative morbidity was recorded in 8.3% of patients, with post-operative haemorrhage, being the most common complication encountered. The mean follow-up was 17 months (SD 15). Local recurrence occurred in 1.6%, and distant organ metastasis was noted in 1.6% of patients. CONCLUSIONS: For carefully selected patients, TAMIS for local excision of early rectal neoplasia is a valid option with low morbidity that maintains the advantages of organ preservation.

Dilemmas in the Clinical Management of pT1 Colorectal Cancer.

Implementation of population-based colorectal cancer screening programs has led to increases in the incidence of pT1 colorectal cancer. These incipient invasive cancers have a very good prognosis and can be treated locally, but more than half of these cases are treated with surgery due to the presence of histological high-risk criteria. These high-risk criteria are suboptimal, with no consensus among clinical guidelines, heterogeneity in definitions and assessment, and poor concordance in evaluation, and recent evidence suggests that some of these criteria considered high risk might not necessarily affect individual prognosis. Current criteria classify most patients as high risk with an indication for additional surgery, but only 2-10.5% have lymph node metastasis, and the residual tumor is present in less than 20%, leading to overtreatment. Patients with pT1 colorectal cancer have excellent disease-free survival, and recent evidence indicates that the type of treatment, whether endoscopic or surgical, does not significantly impact prognosis. As a result, the protective role of surgery is questionable. Moreover, surgery is a more aggressive treatment option, with the potential for higher morbidity and mortality rates. This article presents a comprehensive review of recent evidence on the clinical management of pT1 colorectal cancer. The review analyzes the limitations of histological evaluation, the prognostic implications of histological risk status and the treatment performed, the adverse effects associated with both endoscopic and surgical treatments, and new advances in endoscopic treatment.

[Surgery of the colorectal polyps and early stage cancer - Expected standards]. / Colorectalis polypok és korai rákok sebészete ­ Elvárható standardok.

Benign polyps and early-stage cancer of the colon and rectum traditionally belong to the territory of endoscopic removal. Even though the quality of endoscopic imaging systems and additional diagnostic methods have undergone a substantial evolution over the past decade, large, sessile and lateral-spreading lesions of the large bowel still represent a significant risk of malignancy. This doubt may be undispellable until the removal of the lesion. Therefore endoscopists need to be highly cautious, and keep a very low threshold to involve an expert surgeon even at the phase of diagnostics, as well as treatment. We summarise state-of-the-art treatment principles of benign polyps and early malignant colorectal cancer. Finally, we propose national quality measures of surgical interventions for colorectal polyps.

Transanal Minimally Invasive Surgery for Marsupialization of Chronic Abscess Cavity After Colorectal Anastomosis.

Anastomotic leaks are one of the most feared and morbid complications after colorectal anastomosis. Management of leaks depends on the severity of the leak and focuses on controlling sepsis and saving the anastomosis. The lower the anastomosis, the more amenable it is to transanal approaches for salvage. However, when a complication exists higher up in the rectum, the surgeon is more limited in the ability to visualize and intervene. With the advent of transanal minimally invasive surgery (TAMIS) and the advancement of endoscopic procedures, there are now more options for surgeons to visualize and intervene in anastomotic colorectal leaks. Prior reports have described the use of TAMIS for the management of anastomotic leaks in the acute phase. However, this same approach can be useful in the management of chronic leaks. This report highlights the benefit of TAMIS to allow visualization and marsupialization of a chronic abscess cavity following an anastomotic leak.

Mucosectomy of the anal canal via transanal minimally invasive surgery combined with transanal total mesorectal excision for familial adenomatous polyposis: A technical note.

AIM: Total proctocolectomy with ileal pouch-anal anastomosis (IPAA) is the standard surgical treatment modality for familial adenomatous polyposis (FAP). It is challenging to perform proctectomy and preserve anal sphincter function. In this video, precise mucosectomy of the anal canal via transanal minimally invasive surgery (MAC-TAMIS) is reported. METHODS: An asymptomatic 35-year-old man was found to have a positive faecal occult blood test in routine screening examination and was diagnosed with FAP on colonoscopic examination. The patient was scheduled for total proctocolectomy with IPAA using the TAMIS approach combined with transanal total mesorectal excision. MAC-TAMIS was performed to preserve the internal anal sphincter during laparoscopy. RESULTS: The total duration of surgery was 543 min, blood loss was minimal, and the postoperative course was uneventful. The postoperative hospital stay was 12 days. The pathological findings demonstrated no evidence of malignancy. Gastrographic imaging from the ileostomy showed sufficient size of the J pouch and good tonus of the anus at 6 months after surgery. The Wexner scores at 1, 3 and 6 months after ileostomy closure were 5, 3 and 0, respectively. CONCLUSION: The MAC-TAMIS technique is safe and feasible during total proctocolectomy with IPAA in patients with FAP. This technique allows us to precisely preserve the internal anal sphincter using a laparoscopic approach.

A prospective evaluation of the effect of transanal minimally invasive surgery (TAMIS) on low anterior resection syndrome.

PURPOSE: Transanal minimally invasive surgery (TAMIS) is a surgical alternative to transanal endoscopic microsurgery (TEM), transanal excision and proctectomy in the management of benign rectal polyps and early rectal cancers. Low anterior resection syndrome (LARS) describes the constellation of symptoms which result from and are common after distal colorectal resection. Symptoms include incontinence, frequency, urgency and evacuatory dysfunction. The aim of the current study was to prospectively evaluate pre- and post-operative LARS in patients who undergo TAMIS. METHODS: We conducted a prospective analysis of a consecutive series of patients who underwent TAMIS at our institution between January 2021 and February 2022. A LARS questionnaire was undertaken preoperatively, at 1 month and at 6 months post-operatively. RESULTS: Twenty patients were recruited to this pilot study. The mean age was 63 ± 12 years, 11 of the patients were male, mean pre-operative BMI was 29 ± 6 kg/m2, and 30% (n = 6) of patients underwent TAMIS for an invasive rectal cancer, with all patients receiving an R0 resection. Mean distance from the anal verge was 5.7 ± 3.2 cm, and mean lesion diameter was 46 ± 20.5 mm. A statistically significant interval reduction was observed between preoperative (20.3 ± 12.9) and 6-month post-operative (12.6 ± 9.7) LARS scores (p = 0.02) and also between 1-month (18.2 ± 10.6) and 6-month post-operative scores (p = 0.01). CONCLUSIONS: We noted a high prevalence of LARS across our cohort preoperatively, and this had improved significantly at 6-month review post-TAMIS. This study reaffirms the safety and efficacy of TAMIS for the treatment of early rectal neoplasia.

Robotic Transanal Minimally Invasive Surgery (rTAMIS): Large Tubulovillous Adenoma.

Many transanal platforms have recently evolved to manage rectal pathologies. Transanal endoscopic microsurgery (TEM) and transanal laparoscopic minimally invasive surgery (TAMIS) have been developed to address the limitations of conventional transanal surgery. More recently, the addition of the robotic platform to the surgeon's armamentarium has made it possible to combine the dexterity of the robotic surgical system with the standard TAMIS single-port platform to treat complex rectal lesions. In this article, we present the case of a patient who underwent rTAMIS for the management of a large endoscopically unresectable rectal mass.

Robot-assisted TAMIS: a systematic review of feasibility and outcomes.

BACKGROUND: In the advancement of transanal local excision, robot-assisted transanal minimal invasive surgery is the newest development. In the confined area of the rectum, robot-assisted surgery should, theoretically, be superior due to articulated utensils, video enhancement, and tremor reduction, however, this has not yet been investigated. The aim of this study was to review the evidence reported to-date on experience of using robot-assisted transanal minimal invasive surgery for treatment of rectal neoplasms. METHODS: A comprehensive literature search of Embase and PubMed from May to August 2021were performed. Studies including patients diagnosed with rectal neoplasia or benign polyps who underwent robot-assisted transanal minimal invasive surgery were included. All studies were assessed for risk of bias through assessment tools. Main outcome measures were feasibility, excision quality, and complications. RESULTS: Twenty-five studies with a total of 322 local excisions were included. The studies included were all retrospective, primarily case-reports, -series, and cohort studies. The median distance from the anal verge ranged from 3.5 to 10 cm and the median size was between 2.5 and 5.3 cm. Overall, 4.6% of the resections had a positive resection margin. The overall complication rate was at 9.5% with severe complications (Clavien-Dindo score III) at 0.9%. CONCLUSION: Based on limited, retrospective data, with a high risk of bias, robot-assisted transanal minimal invasive surgery seems feasible and safe for local excisions in the rectum.

Multicenter clinical trial for the resection of rectal polyps using a new laparoendoscopic hybrid transanal access device.

INTRODUCTION: Complex polyps require the use of advanced endoscopic techniques or minimally invasive surgery for their approach. In rectal polyps it is of special relevance to reach a consensus on the best approach to avoid under- or overtreatment that increases unnecessary morbidity and mortality. METHODS: We describe a prospective, multicenter, pilot clinical trial with a first-in-human medical device. It is hypothesized that UNI-VEC® facilitates transanal laparoendoscopic surgery for the removal of early rectal tumors. The primary objective is to evaluate that it is safe and meets the established functional requirements. Secondary objectives are to evaluate results, complications and level of satisfaction. RESULTS: 16 patients were recruited in 12 months with a minimum follow-up of 2 months. The mean size was 3.4 cm with the largest polyp being 6 cm. Regarding location, the mean was 6.6 cm from the anal margin. Endoscopic Mucosal Resection (EMR) (6.3%), Endoscopic Submucosal Dissection ESD (43.8%), REC (6.3%) and TAMIS (43.8%) were performed. The mean time was 73.25 min. The 56.3% used a 30° camera and 43.8% used the flexible endoscope as a viewing instrument. The 56.3% were benign lesions and 43.8% malignant. Complete resection is achieved in 87.5%. Regarding complications, mild bleeding (Clavien I) occurred in 25%, 6.3% and 21.4% at 24 h, 48 h and 7 days respectively. Continence was assessed according to the Wexner scale. At 7 days, 60% showed perfect continence, 26.7% mild FI and 13.3% moderate FI. At 30 days, 66.7% had perfect continence, 20% mild FI and 13.3% moderate FI. At 2 months, 4 patients were reviewed who at 30 days had a Wexner's degree higher than preoperative and perfect continence was demonstrated in 25% of the patients, 50% mild and 25% moderate. In no case did rectal perforation or major complications requiring urgent reintervention occur. As for the level of reproducibility, safety, level of satisfaction with the device and evaluation of the blister, the evaluation on a scale of 0-10 (9.43, 9.71, 9.29 and 9.50 respectively). All the investigators have previous experience with transanal devices. CONCLUSIONS: The study demonstrates the efficacy and safety of UNI-VEC® for the treatment of rectal lesions. It will facilitate the implementation of hybrid procedures that seek to solve the limitations of pure endoscopic techniques by allowing the concomitant use of conventional laparoscopic and robotic instrumentation with the flexible endoscope.

Classification of surgical causes of and approaches to the chronically failing ileoanal pouch.

BACKGROUND: Although there are various surgical causes of and therapeutic approaches to the chronically failing ileoanal pouch (PF), cases are often detailed without distinguishing the exact cause and corresponding treatment. The aim of our study was to classify causes of PF and corresponding surgical treatment options, and to establish efficacy of surgical approach per cause. METHODS: This retrospective study included all consecutive adult patients with chronic PF surgically treated at our tertiary hospital between July 2014 and March 2021. Patients were classified according to a proposed sub-classification for surgical related chronic PF. Results were reported accordingly. RESULTS: A total of 59 procedures were completed in 50 patients (64% male, median age 45 years [IQR 34.5-54.3]) for chronic PF. Most patients had refractory ulcerative colitis as indication for their restorative proctocolectomy (68%). All patients could be categorized according to the sub-classification. Reasons for chronic PF were septic complications (n = 25), pouch body complications (n = 12), outlet problems (n = 11), cuff problems (n = 8), retained rectum (n = 2), and inlet problems (n = 1). For these indications, 17 pouches were excised, 10 pouch reconstructions were performed, and 32 pouch revision procedures were performed. The various procedures had different complication rates. Technical success rates of redo surgery for the different causes varied from 0 to 100%, with a 75% success rate for septic causes. CONCLUSIONS: Our sub-classification for chronic PF and corresponding treatments is suitable for all included patients. Outcomes varied between causes and subsequent management. Chronic PF was predominantly caused by septic complications with redo surgery achieving a 75% technical success rate.

The endorectal incision level of transanal total mesorectal excision (taTME): An emphasis on the distance from the anterior vs. posterior mesorectal ends to the anal verge.

BACKGROUND: There is no intraluminal guidance to ensure complete inclusion of the mesorectum in transanal total mesorectal excision (taTME). This study aimed to assess the distance difference between the anterior and posterior mesorectal terminal ends and the anal verge as a potential risk for residual mesorectum after resection. METHODS: Forty-four surgical specimens of extra-levator abdominoperineal excision (ELAPE) and 28 mid-sagittal cadaveric specimens were included to this study. The distance between the mesorectum terminal end (T) and the endoluminal landmarks (dentate line (D)/anal verge (A)) was measured and compared between men and women. Furthermore, 66 MRI images from The Cancer Imaging Archive (TCIA) were used to validate the same concept in a non-Asian population. RESULTS: The mesorectal terminal end was found to be aligned along with the levator hiatus. From the midsagittal view, the ELAPE specimens showed that the distance between T and A anteriorly was significantly longer than the same distance posteriorly (34.74±7.79mm vs 23.74±4.24mm, P<0.001). Similarly, the distance measured in the cadaveric specimens was significantly longer anteriorly than posteriorly (P<0.001). The validation cohort of non-Asian MRI image has confirmed the same (56.68±14.17mm vs. 38.18 ±10.42mm, P<0.001(. There was no significant difference between men and women. CONCLUSIONS: Because of the remarkable distance difference between the anterior and posterior mesorectal terminal ends away from the anal verge, the taTME proctectomy level may not meet the required mesorectal end. Thus, if TME is planned, aligning the proctectomy level around the levator hiatus would be the best place that can ensure complete TME.