Intersphincteric resection (ISR) is the ultimate sphincter-preserving surgical technique for low rectal cancer. Accurate preoperative diagnosis and staging, appropriate selection of surgical approaches and technique, standardized perioperative management, and postoperative rehabilitation are the keys to ensuring the oncological effect and functional preservation of ISR. To date, there is still a lack of standardized guidance on the clinical implementation of ISR in China. Therefore, based on the latest evidence from literature, expert experience, and the intervention situation in China, the Chinese Society of Colorectal Surgery, Chinese Society of Surgery, Chinese Medical Association organized domestic experts in colorectal surgery to discuss and produce "Chinese expert consensus on intersphincteric resection for low rectal cancer (2023 edition)". This consensus focuses on definition, classification, related pelvic anatomy, operational techniques, postoperative complications, and long-term oncological and functional outcomes, and aims to guide the standardized clinical practice of ISR in the operation of low rectal cancer in China.
Humans ; Laparoscopy/methods* ; Consensus ; Anal Canal/surgery* ; Digestive System Surgical Procedures/methods* ; Rectal Neoplasms/surgery* ; Treatment Outcome

Intersphincteric resection (ISR) is the ultimate sphincter-preserving surgical technique for low rectal cancer. To promote the standardized implementation of ISR, this review discusses the important issues regarding the clinical application of ISR with reference to the latest Chinese expert consensus on ISR. In terms of ISR-related pelvic anatomy of the rectum/anal canal, hiatal ligament is not identical with the anococcygeal ligament. At the level where the rectourethralis muscle continuously extends to the posteroinferior area of the membranous urethra from the rectum, the neurovascular bundle is identified between the posterior edge of rectourethralis muscle and the anterior edge of the longitudinal muscle of the rectum. This knowledge is crucial to detect the anterior dissection plane during ISR at the levator hiatus level. The indication criteria for ISR included: (1) stage I early low rectal cancer; (2) stage II-III low rectal cancer undergoing neoadjuvant treatment, and supra-anal tumors and juxta-anal tumors of stage ycT3NxM0, or intra-anal tumors of stage ycT2NxM0. However, signet ring cell carcinoma, mucinous adenocarcinoma and undifferentiated carcinoma should be contraindicated to ISR. For locally advanced low rectal cancer (especially anteriorly located tumor), neoadjuvant treatment should be carried out in a standardized manner. However, it should be recognized that neoadjuvant chemoradiotherapy was a risk factor for poor anal function after ISR. For surgical approaches for ISR, including transanal, transabdominal, and transanal transabdominal approaches, the choice should be based on oncological safety and functional consequences. While ensuring the negative margin, maximal preservation of rectal walls and anal canal contributs to better postoperative anorectal function. Careful attention must be paid to complications regarding ISR, with special focus on the anastomotic complications. The incidence of low anterior resection syndrome (LARS) was higher than 40%. However, this issue is often neglected by clinicians. Thus, management and rehabilitation strategies for LARS with longer follow-ups were required.
Humans ; Rectal Neoplasms/pathology* ; Postoperative Complications ; Laparoscopy/methods* ; Anal Canal/pathology* ; Anus Neoplasms/pathology* ; Anus Diseases/surgery* ; Low Anterior Resection Syndrome ; Carcinoma, Signet Ring Cell/pathology* ; Treatment Outcome

ISR is the most widely used anal-preserving operation for ultra-low rectal cancer. It can be divided into total ISR, subtotal ISR and partial ISR according to the resection range of internal sphincter. The advantage of ISR is that it can preserve the sphincter while ensuring the safety of oncology for ultra-low rectal cancer, representing the state of the art. However, it still needs to face the problem that the quality of life will decline due to poor postoperative anal function. The conformal sphincter-preserving operation (CSPO) is a functional anal-preserving surgery improved on the basis of ISR. It is superior to ISR in the postoperative anal function and patients' quality of life. So it can be a new choice for ultra-low rectal cancer.
Humans ; Quality of Life ; Rectal Neoplasms/surgery* ; Anal Canal/surgery* ; Digestive System Surgical Procedures/methods* ; Anastomosis, Surgical ; Treatment Outcome

The anatomical studies of intersphincteric resection (ISR) have made remarkable progress in recent years. The anatomy of internal, external sphincter and hiatal ligament has been further understood. In this paper, the generation and functional mechanism of ISR related anatomy are described from the embryonic development process, and then the influence of hiatal ligament and internal sphincter on ISR surgery is analyzed respectively according to the anatomical characteristics. Finally, the correlation analysis of anatomical factors on the common problems of mucosal bleeding and instrument anastomosis in ISR is carried out. The objective of this paper is to improve the safety of ISR surgery by providing detailed anatomical explanations.
Humans ; Anal Canal/surgery* ; Rectal Neoplasms/surgery* ; Clinical Relevance ; Anastomosis, Surgical

Intersphincteric resection (ISR) surgery increases the rate of anal sphincter preservation in patients with ultra-low rectal cancers. However, the anastomotic site of ISR surgery is at risk for structural healing complications such as anastomotic leakage, anastomotic dehiscence, secondary anastomotic stenosis, chronic presacral sinus, rectovaginal fistula, and rectourethral fistula, which can lead to a persistent defunctioning ostomy or a secondary permanent colostomy. This article systematically describes the preoperative high-risk factors and characteristics of anastomotic site structural healing complications after ISR surgery, as well as the management of the anastomotic site during various stages including hospitalization, from discharge to one month after surgery, from one month after surgery to before stoma reversal, and after stoma reversal. This is to provide a clearer understanding of the risks associated with the anastomotic site at different stages of the healing process and to timely detect and actively manage related complications, thereby reducing the rate of permanent colostomy and truly achieving the dual goals of "survival benefit" and "quality of life improvement" in ISR surgery.
Female ; Humans ; Anal Canal/surgery* ; Quality of Life ; Anastomosis, Surgical/adverse effects* ; Anastomotic Leak/etiology* ; Rectal Neoplasms/complications* ; Retrospective Studies

Objective: To document the anatomical structure of the area anterior to the anorectum passing through the levator hiatus between the levator ani slings bilaterally. Methods: Three male hemipelvises were examined at the Laboratory of Clinical Applied Anatomy, Fujian Medical University. (1) The anatomical assessment was performed in three ways; namely, by abdominal followed by perineal dissection, by examining serial cross-sections, and by examining median sagittal sections. (2) The series was stained with hematoxylin and eosin to enable identification of nerves, vessels, and smooth and striated muscles. Results: (1) It was found that the rectourethralis muscle is closest to the deep transverse perineal muscle where the longitudinal muscle of the rectum extends into the posteroinferior area of the membranous urethra. The communicating branches of the neurovascular bundle (NVB) were identified at the posterior edge of the rectourethralis muscle on both sides. The rectum was found to be fixed to the membranous urethra through the rectourethral muscle, contributing to the anorectal angle of the anterior rectal wall. (2) Serial cross-sections from the anal to the oral side were examined. At the level of the external anal sphincter, the longitudinal muscle of the rectum was found to extend caudally and divide into two muscle bundles on the oral side of the external anal sphincter. One of these muscle bundles angled dorsally and caudally, forming the conjoined longitudinal muscle, which was found to insert into the intersphincteric space (between the internal and external anal sphincters). The other muscle bundle angled ventrally and caudally, filling the gap between the external anal sphincter and the bulbocavernosus muscle, forming the perineal body. At the level of the superficial transverse perineal muscle, this small muscle bundle headed laterally and intertwined with the longitudinal muscle in the region of the perineal body. At the level of the rectourethralis and deep transverse perineal muscle, the external urethral sphincter was found to occupy an almost completely circular space along the membranous part of the urethra. The dorsal part of the external urethral sphincter was found to be thin at the point of attachment of the rectourethralis muscle, the ventral part of the longitudinal muscle of the rectum. We identified a venous plexus from the NVB located close to the oral and ventral side of the deep transverse perineal muscle. Many vascular branches from the NVB were found to be penetrating the longitudinal muscle and the ventral part of rectourethralis muscle at the level of the apex of the prostate. The rectourethral muscle was wrapped ventrally around the membranous urethra and apex of the prostate. The boundary between the longitudinal muscle and prostate gradually became more distinct, being located at the anterior end of the transabdominal dissection plane. (3) Histological examination showed that the dorsal part of the external urethral sphincter (striated muscle) is thin adjacent to the striated muscle fibers from the deep transverse perineal muscle and the NVB dorsally and close by. The rectourethral muscle was found to fill the space created by the internal anal sphincter, deep transverse perineal muscle, and both levator ani muscles. Many tortuous vessels and tiny nerve fibers from the NVB were identified penetrating the muscle fibers of the deep transverse perineal and rectourethral muscles. The structure of the superficial transverse perineal muscle was typical of striated muscle. These findings were reconstructed three-dimensionally. Conclusions: In intersphincteric resection or abdominoperineal resection for very low rectal cancer, the anterior dissection plane behind Denonvilliers' fascia disappears at the level of the apex of the prostate. The prostate and both NVBs should be used as landmarks during transanal dissection of the non-surgical plane. The rectourethralis muscle should be divided near the rectum side unless tumor involvement is suspected. The superficial and deep transverse perineal muscles, as well as their supplied vessels and nerve fibers from the NVB. In addition, the cutting direction should be adjusted according to the anorectal angle to minimize urethral injury.
Humans ; Male ; Rectum/surgery* ; Anal Canal/anatomy & histology* ; Rectal Neoplasms/surgery* ; Proctectomy ; Urethra/surgery*

Objective: To compare the long-term outcomes of intersphincteric (trans-internal and external) sphincter resection (ISR) and abdominoperineal proctocolectomy (APR) for low-grade rectal cancer. Methods: We used a meta-analytic approach to compare these procedures . Published reports comparing ISR and APR for low rectal cancer in Pubmed, Medline, EMBASE and Cochrane, China Knowledge Network (CNKI), China Biomedical Literature Database, and Vipers databases between January 2005 and January 2023 were searched and those meeting the eligibility criteria were selected for extraction of data for analysis. Inclusion criteria were as follows: (1) all reports comparing ISR and APR for low rectal cancer before January 2023; and (2) prospective randomized controlled studies or well-designed cohort studies. Exclusion criteria were as follows: (1) full text not available; (2) duplicate publications, missing primary outcome indicators, and unknown data; and (3) invalid statistical analysis. Results: Sixteen studies with 2498 patients were included in this study. Compared with the APR group, patients in the ISR group were relatively younger (weighted mean difference [WMD]=-1.82, 95%CI=-2.94 to -0.70, P=0.01), had tumors farther from the anal verge (WMD=0.43, 95%CI=0.18 to 0.67, P<0.01), and lower pathological T-stage (T3-4 stage: OR=0.54, 95%CI=0.36 to 0.81, P<0.01). In contrast, there were no statistically significant differences between the two groups in gender (P=0.78), body mass index (P=0.77), or pathological N stage (P=0.09). Compared with the APR group, patients in the ISR group had a lower rate of postoperative complications (OR=0.77, 95%CI=0.60 to 0.99, P=0.04), shorter hospital stay (WMD=-4.30, 95%CI=-7.07 to -1.53, P<0.01), higher 5-year overall survival (HR=0.54, 95%CI=0.33 to 0.88, P=0.01), and higher 5-year disease-free survival (HR=0.65, 95%CI=0.47 to 0.90, P<0.01). Five-year locoregional failure (HR=0.66, 95%CI=0.40 to 1.10, P=0.11) and time to surgery (WMD=-9.71, 95%CI=-41.89 to 22.47, P=0.55) did not differ significantly between the two groups. Conclusion: ISR is a safe and effective alternative to APR for early-stage low-grade rectal cancer.
Humans ; Prospective Studies ; Rectal Neoplasms/pathology* ; Rectum/surgery* ; Proctectomy ; Anal Canal/pathology* ; Treatment Outcome

Intersphincteric resection (ISR) has been performed as an ultimate sphincter-sparing strategy in selected patients with low rectal cancer. Accumulating evidence suggests that ISR may be an interesting alternative to abdominoperineal resection to avoid a permanent stoma without compromising oncological outcomes. However, bowel dysfunction is a most common consequence of ISR not to be neglected. To date, limited clinical research has reported functional and quality of life outcomes according to patient-reported outcome measures. Also, data concerning management of low anterior resection syndrome are scarce due to lack of quality evidence. Therefore, this review provides an up-to-date summary of systematic assessment (including function, quality of life, manometry and morphology) and bowel rehabilitation for ISR patients. Postoperative anal function is often assessed by a combination of scales, including the Incontinence Assessment Scale, the Gastrointestinal Function Questionnaire, the Specific LARS Assessment Scale and the Faecal Diary. The condition-specific Quality of Life Scale is more appropriate for Quality-of-life measures in fecal incontinence after ISR. Patients' physiological function after ISR can be assessed using water- or high-resolution solid-state anorectal manometry. Anatomical and morphological changes can be assessed using defecography and 3D endorectal ultrasound. Electrical stimulation and biofeedback, pelvic floor exercises, rectal balloon training, transanal irrigation and sacral neuromodulation are all options for post-operative rehabilitation.
Humans ; Rectal Neoplasms/surgery* ; Postoperative Complications ; Anal Canal/surgery* ; Quality of Life ; Organ Sparing Treatments ; Fecal Incontinence

Objective: To report the perioperative management and robot-assisted minimally invasive surgery results of one case with malignant tumor of anal canal combined with severe abdominal distention. Methods: A 66-year-old male suffer from adenocarcinoma of anal canal (T3N0M0) with megacolon, megabladder and scoliosis. The extreme distention of the colon and bladder result in severe abdominal distention. The left diaphragm moved up markedly and the heart was moved to the right side of the thoracic cavity. Moreover, there was also anal stenosis with incomplete intestinal obstruction. Preoperative preparation: fluid diet, intravenous nutrition and repeated enema to void feces and gas in the large intestine 1 week before operation. Foley catheter was placed three days before surgery and irrigated with saline. After relief of abdominal distention, robotic-assisted abdominoperineal resection+ subtotal colectomy+colostomy was performed. Results: Water intake within 6 hours post-operatively; ambulance on Day 1; anal passage of gas on Day 2; semi-fluid diet on Day 3; safely discharged on Day 6. Conclusion: Robotic-assisted minimally invasive surgery is safe and feasible for patients with malignant tumor of anal canal combined with severe abdominal distention after appropriate and effective preoperative preparation to relieve abdominal distention.
Male ; Humans ; Aged ; Anal Canal/surgery* ; Colon/surgery* ; Colectomy ; Anus Diseases/surgery* ; Adenocarcinoma/surgery* ; Digestive System Abnormalities/surgery*

Objective: In this study, we aimed to investigate the prevalence of low anterior resection syndrome (LARS) in patients who had survived for more than 5 years after sphincter-preserving surgery for rectal cancer and to analyze its relationship with postoperative time. Methods: This was a single-center, retrospective, cross-sectional study. The study cohort comprised patients who had survived for at least 5 years (60 months) after undergoing sphincter- preserving radical resection of pathologically diagnosed rectal adenocarcinoma within 15 cm of the anal verge in the Department of Gastrointestinal Surgery, Peking University People's Hospital from January 2005 to May 2016. Patients who had undergone local resection, had permanent stomas, recurrent intestinal infection, local recurrence, history of previous anorectal surgery, or long- term preoperative defecation disorders were excluded. A LARS questionnaire was administered by telephone interview, points being allocated for incontinence for flatus (0-7 points), incontinence for liquid stools (0-3 points), frequency of bowel movements (0-5 points), clustering of stools (0-11 points), and urgency (0-16 points). The patients were allocated to three groups based on these scores: no LARS (0-20 points), minor LARS (21-29 points), and major LARS (30-42 points). The prevalence of LARS and major LARS in patients who had survived more than 5 years after surgery, correlation between postoperative time and LARS score, and whether postoperative time was a risk factor for major LARS and LARS symptoms were analyzed. Results: The median follow-up time of the 160 patients who completed the telephone interview was 97 (60-193) months; 81 (50.6%) of them had LARS, comprising 34 (21.3%) with minor LARS and 47 (29.4%) with major LARS. Spearman correlation analysis showed no significant correlation between LARS score and postoperative time (correlation coefficient α=-0.016, P=0.832). Multivariate analysis identified anastomotic height (RR=0.850, P=0.022) and radiotherapy (RR=5.760, P<0.001) as independent risk factors for major LARS; whereas the postoperative time was not a significant risk factor (RR=1.003, P=0.598). The postoperative time was also not associated with LARS score rank and frequency of bowel movements, clustering, or urgency (P>0.05). However, the rates of incontinence for flatus (3/31, P=0.003) and incontinence for liquid stools (8/31, P=0.005) were lower in patients who had survived more than 10 years after surgery. Conclusions: Patients with rectal cancer who have survived more than 5 years after sphincter-preserving surgery still have a high prevalence of LARS. We found no evidence of major LARS symptoms resolving over time.
Humans ; Rectal Neoplasms/pathology* ; Cross-Sectional Studies ; Low Anterior Resection Syndrome ; Postoperative Complications/etiology* ; Retrospective Studies ; Flatulence/complications* ; Anal Canal/pathology* ; Diarrhea ; Quality of Life