Robotic vs laparoscopic abdominoperineal resection for rectal cancer:A propensity score matching cohort study and metaanalysis

BACKGROUND Robotic surgery(RS)is gaining popularity;however,evidence for abdominoperineal resection(APR)of rectal cancer(RC)is scarce.AIM To compare the efficacy of RS and laparoscopic surgery(LS)in APR for RC.METHODS We retrospectively identified patients with RC who underwent APR by RS or LS from April 2016 to June 2022.Data regarding short-term surgical outcomes were compared between the two groups.To reduce the effect of potential confounding factors,propensity score matching was used,with a 1:1 ratio between the RS and LS groups.A meta-analysis of seven trials was performed to compare the efficacy of robotic and laparoscopic APR for RC surgery.RESULTS Of 133 patients,after propensity score matching,there were 42 patients in each group.The postoperative complication rate was significantly lower in the RS group(17/42,40.5%)than in the LS group(27/42,64.3%)(P=0.029).There wasno significant difference in operative time(P=0.564),intraoperative transfusion(P=0.314),reoperation rate(P=0.314),lymph nodes harvested(P=0.309),or circumferential resection margin(CRM)positive rate(P=0.314)between the two groups.The meta-analysis showed patients in the RS group had fewer positive CRMs(P=0.04),lesser estimated blood loss(P<0.00001),shorter postoperative hospital stays(P=0.02),and fewer postoperative complications(P=0.002)than patients in the LS group.CONCLUSION Our study shows that RS is a safe and effective approach for APR in RC and offers better short-term outcomes than LS.

Extralevator abdominoperineal excision for advanced low rectal cancer:Where to go

Since its introduction,extralevator abdominoperineal excision(ELAPE)in the prone position has gained significant attention and recognition as an important surgical procedure for the treatment of advanced low rectal cancer.Most studies suggest that because of adequate resection and precise anatomy,ELAPE could decrease the rate of positive circumferential resection margins,intraoperative perforation,and may further decrease local recurrence rate and improve survival.Some studies show that extensive resection of pelvic floor tissue may increase the incidence of wound complications and urogenital dysfunction.Laparoscopic/robotic ELAPE and trans-perineal minimally invasive approach allow patients to be operated in the lithotomy position,which has advantages of excellent operative view,precise dissection and reduced postoperative complications.Pelvic floor reconstruction with biological mesh could significantly reduce wound complications and the duration of hospitalization.The proposal of individualized ELAPE could further reduce the occurrence of postoperative urogenital dysfunction and chronic perianal pain.The ELAPE procedure emphasizes precise anatomy and conforms to the principle of radical resection of tumors,which is a milestone operation for the treatment of advanced low rectal cancer.

Biological mesh reconstruction of the pelvic floor following abdominoperineal excision for cancer:A review

Extralevator abdominoperineal excision and pelvic exenteration are mutilating operations that leave wide perineal wounds.Such large wounds are prone to infection and perineal herniation,and their closure is a major concern to most surgeons.Different approaches to the perineal repair exist,varying from primary or mesh closure to myocutaneous flaps.Each technique has its own associated advantages and potential complications and the ideal approach is still debated.In the present study,we reviewed the current literature and our own local data regarding the use of biological mesh for perineal wound closure.Current evidence suggests that the use of biological mesh carries an acceptable risk of wound complications compared to primary closure and is similar to flap reconstruction.In addition,the rate of perineal hernia is lower in early follow-up,while long-term hernia occurrence appears to be similar between the different techniques.Finally,it is an easy and quick reconstruction method.Although more expensive than primary closure,the cost associated with the use of a biological mesh is at least equal,if not less,than flap reconstruction.

Laparoscopic vs open abdominoperineal resection in the multimodality management of low rectal cancers

AIM: To evaluate the safety and feasibility of laparoscopic abdominoperineal resection compared with the open procedure in multimodality management of rectal cancer.METHODS: A total of 106 rectal cancer patients who underwent open abdominoperineal resection(OAPR) were matched with 106 patients who underwent laparoscopic abdominoperineal resection(LAPR) in a 1 to 1 fashion, between 2009 and 2013 at Fudan University Shanghai Cancer Center. Propensity score matching was carried out based on age, gender, pathological staging of the disease and administration of neoadjuvant chemoradiation. Data regarding preoperative staging, surgical technique, pathologicalresults, postoperative recovery and complications were reviewed and compared between the LAPR and OAPR groups. Perineal closure around the stoma and pelvic floor reconstruction were performed only in OAPR, not in LAPR. Therefore, abdominoperineal resection procedure-specific surgical complications including parastomal hernia and perineal wound complications were compared between the open and laparoscopic procedure. Regular surveillance of the two cohorts was carried out to gather prognostic data. Diseasefree survival was analyzed using Kaplan-Meier estimate and log-rank test. Subgroup analysis was performed in patients with locally advanced disease treated with preoperative chemoradiation followed by surgical resection. RESULTS: No significant difference was found between the LAPR group and the OAPR group in terms of clinicopathological features. The operation time(180.8 ± 47.8 min vs 172.1 ± 49.2 min, P = 0.190), operative blood loss(93.9 ± 60.0 m L vs 88.4 ± 55.2 m L, P = 0.494), total number of retrieved lymph nodes(12.9 ± 6.9 vs 12.9 ± 5.4, P = 0.974), surgical complications(12.3% vs 15.1%, P = 0.549) and pathological characteristics were comparable between the LAPR and OAPR group, respectively. Compared with OAPR patients, LAPR patients showed significantly shorter postoperative analgesia(2.4 ± 0.7 d vs 2.7 ± 0.6 d, P < 0.001), earlier first flatus(57.3 ± 7.9 h vs 63.5 ± 9.2 h, P < 0.001), shorter urinary drainage time(6.5 ± 3.4 d vs 7.8 ± 1.3 d, P < 0.001), and shorter postoperative admission(11.2 ± 4.7 d vs 12.6 ± 4.0 d, P = 0.014). With regard to APR-specific complications(perineal wound complications and parastomal hernia), there were no significant differences between the two groups. Similar results were found in the 26 pairs of patients administered neoadjuvant chemoradiation in subgroup analysis. During the follow-up period, no port site recurrences were observed. CONCLUSION: Laparoscopic abdominoperineal resection for multidisciplinary management of rectal cancer is safe, and is associated with earlier recovery and shorter admission time in combination with neoadjuvant chemoradiation.

Abdominoperineal excision following preoperative radiotherapy for rectal cancer: Unfavorable prognosis even with negative circumferential resection margin

AIM: To evaluate whether an abdominoperineal excision(APE) is associated with increased local recurrence(LR) and shortened disease-free survival(DFS) in mid-low rectal cancer with a negative circumferential resection margin(CRM).METHODS: 283 consecutive cases of mid-low rectal cancer underwent preoperative 30 Gy/10 F radiotherapy and surgery in Peking University Cancer Hospital between August 2003 and August 2009. Patients with positive CRM and intraoperative distant metastasis were precluded according to exclusion criteria. Survival analyses were performed in patients with APE or non-APE procedures.RESULTS: 256 of the 283(90.5%) cases were enrolled in the analysis, including 78(30.5%) and 178(69.5%) cases who received APE and non-APE procedures. Fewer female patients(P = 0.016), lower level of tumor(P = 0.000) and higher body mass index(P = 0.006) were found in the APE group. On univariate analysis, the APE group had a higher LR rate(5.1% vs 1.1%, P = 0.036) and decreased DFS(73.1% vs 83.4%, P = 0.021). On multivariate analysis, APE procedure was also an independent risk factor for LR(HR = 5.960, 1.085-32.728, P = 0.040) and decreased DFS(HR = 2.304, 1.298-4.092, P = 0.004). In stratified analysis for lower rectal cancer, APE procedure was still an independent risk factor for higher LR rate(5.6% vs 0%, P = 0.024) and shortened DFS(91.5% vs 73.6%, P = 0.002).CONCLUSION: Following preoperative 30 Gy/10 F radiotherapy, APE procedure was still a predictor for LR and decreased DFS even with negative CRM. More intensive preoperative treatment should be planned for the candidates who are scheduled to receive APE with optimal imaging assessment.

Perineal Hernia after Laparoscopic Abdominoperineal Resection for Rectal Cancer: A Case Report and Review of the Literature

Perineal hernias are uncommon complications following laparoscopic abdominoperineal operations. There is still very little known about perineal hernia. There are only few case reports to describe the repair of postoperative hernias after laparoscopic abdominoperineal resection (APR) in the literature. Here we present one patient with a perineal hernia after laparoscopic abdominoperineal resection for rectal cancer. The surgical management with manual purse-string suture is described and discussed in this case report.

Abdominoperineal Resection in Rectal Cancer in General Surgery Department at Gabriel Toure University Hospital

The objectives: Were to determine the hospital frequency of abdominoperineal resection (APR);to determine mortality and morbidity rates and to assess oncologic outcomes. Method and patients: We performed a retrospective study between 2008 and 2013 in general surgery department at Gabriel Toure University Hospital (UH) which included all patients admitted for rectal cancer confirmed by pathological examination, and having undergone an APR. Results: We have collected 17 cases which accounted for 65.38% of curative resections of rectal cancer. The sex-ratio was 0.89 and the averageage was 49.53 years. The average tumor distance from the anal verge was 4.59 ± 1.7 cm. All patients had adenocarcinoma of the rectum. The histopathologic grade was well in 7 cases, moderate and poor in 5 cases each. According to the pathologic TNM classification, 13 patients were classified T4, 14 patients N+. APR was associated with hysterectomy and partial colpectomy in 4 cases. The average duration of interventions was 202.06 ± 25.68 minutes. The average duration of hospitalization was 18.24 ± 04.89 days. The postoperative mortality and morbidity rates were 5.88% and 29.42%, respectively. Local recurrence was observed in 6 patients and liver metastasis in 2 patients. The overall survival rate was 37.5% at 2 years and 18.75% at 5 years. Conclusion: APR still occupies an important place in our practice. Our results could be improved by the recent introduction of neoadjuvant radio chemotherapy in Mali.

Application of Laparoscopic Extralevator Abdominoperineal Excision in Locally Advanced Low Rectal Cancer

Background：When compared with conventional abdominoperineal resection （APR）,extralevator abdominoperineal excision （ELAPE） has been demonstrated to reduce the risk of local recurrence for the treatment of locally advanced low rectal cancer.Combined with the laparoscopic technique,laparoscopic ELAPE （LELAPE） has the potential to reduce invasion and hasten postoperative recovery.In this study,we aim to investigate the advantages of LELAPE in comparison with conventional APR.Methods：From October 2010 to February 2013,23 patients with low rectal cancer （T3-4N0-2M0） underwent LELAPE;while during the same period,25 patients were treated with conventional APR.The patient characteristics,intraoperative data,postoperative complications,and follow-up results were retrospectively compared and analyzed.Results：The basic patient characteristics were similar;but the total operative time for the LELAPE was longer than that of the conventional APR group （P =0.014）.However,the operative time for the perineal portion was comparable between the two groups （P =0.328）.The LELAPE group had less intraoperative blood loss （P =0.022）,a lower bowel perforation rate （P =0.023）,and a positive circumferential margin （P =0.028）.Moreover,the patients,who received the LELAPE,had a lower postoperative Visual Analog Scale,quicker recovery of bowel function （P =0.001）,and a shorter hospital stay （P =0.047）.However,patients in the LELAPE group suffered more chronic perineal pain （P =0.002）,which may be related to the coccygectomy （P =0.033）.Although the metastasis rate and mortality rate were similar between the two groups,the local recurrence rate of the LELAPE group was statistically improved （P =0.047）.Conclusions：When compared with conventional APR,LELAPE has the potential to reduce the risk of local recurrence,and decreases operative invasion for the treatment of locally advanced low rectal cancer.

Extralevator abdominoperineal excision versus abdominoperineal excision for low rectal cancer: a meta-analysis

Background:Extralevator abdominoperineal excision (ELAPE) has become a popular procedure for low rectal cancer as compared with abdominoperineal excision (APE). No definitive answer has been achieved whether one is superior to the other. This study aimed to evaluate the safety and efficacy of ELAPE for low rectal cancer with meta-analysis.Methods:The Web of Science, Cochrane Library, Embase, and PubMed databases before September 2019 were comprehensively searched to retrieve comparative trials of ELAPE and APE for low rectal cancer. Pooled analyses of the perioperative variables, surgical complications, and oncological variables were performed. Odds ratio (OR) and mean differences (MD) from each trial were pooled using random or fixed effects model depending on the heterogeneity of the included studies. A subgroup analysis or a sensitivity analysis was conducted to explore the potential source of heterogeneity when necessary.Results:This meta-analysis included 17 studies with 4049 patients, of whom 2248 (55.5%) underwent ELAPE and 1801 (44.5%) underwent APE. There were no statistical differences regarding the circumferential resection margin positivity (13.0% vs. 16.2%, OR = 0.69, 95% CI = 0.42-1.14, P = 0.15) and post-operative perineal wound complication rate (28.9% vs. 24.1%, OR = 1.21, 95% CI = 0.75-1.94, P= 0.43). The ELAPE was associated with lower rate of intraoperative perforation (6.6% vs. 11.3%, OR = 0.50, 95% CI = 0.39-0.64, P < 0.001) and local recurrence (8.8% vs. 20.5%, OR = 0.29, 95% CI = 0.21-0.41, P < 0.001) when compared with APE.Conclusions:The ELAPE was associated with a reduction in the rate of intra-operative perforation and local recurrence, without any increase in the circumferential resection margin positivity and post-operative perineal wound complication rate when compared with APE in the surgical treatment of low rectal cancer.

Preliminary Outcome of Individualized Abdominoperineal Excision for Locally Advanced Low Rectal Cancer

Background： The introduction of individualized abdominoperineal excision （APE） may minimize operative trauma and reduce the rate of complications. The purpose of this study was to evaluate the safety and efficacy of individualized APE for low rectal cancer. Methods： Fifty-six patients who underwent individualized APE from June 2011 to June 2015 were evaluated retrospectively in Beijing Chaoyang Hospital, Capital Medical University. The main outcome measures were circumferential resection margin （CRM） involvement, intraoperative perforation, postoperative complications, and local recurrence. Statistical analysis was performed using SPSS version 16.0. Results： Fifty （89%） patients received preoperative chemoradiotherapy： 51 （91%） patients were treated with the sacrococcyx preserved; 27 （48%） patients with the levator ani muscle partially preserved bilaterally; 20 （36%） patients with the levator ani muscle partially preserved unilaterally and the muscle on the opposite side totally preserved; 7 （13%） patients with intact levator ani muscle and part of the ischioanal fat bilaterally dissected; and 2 （4%） patients with part of the ischioanal fat and intact lavator ani muscle dissected unilaterally and the muscle on the opposite side partially preserved. The most common complications included sexual dysfunction （12%）, perineal wound complications （13%）, urinary retention （7%）, and chronic perineal pain （5%）. A positive CRM was demonstrated in 3 （5%） patients, and intraoperative perforations occurred in 2 （4%） patients. On multiple logistic regression analysis, longer operative time （P = 0.032） and more intraoperative blood loss （P = 0.006） were significantly associated with perineal procedure-related complications. The local recurrence was 4% at a median follow-up of 53 months （range： 30–74 months）. Conclusion： With preoperative chemoradiotherapy, individualized APE may be a relatively safe and feasible approach for low rectal cancer with acceptable oncological outcomes.

Prospective study of reconstructing pelvic floor with GORE-TEX Dual Mesh in abdominoperineal resection

Background Mesh reconstruction has been proved to be an effective method in incisional hernia repairment. This study was designed to evaluate the effect of reconstructing the pelvic floor with the high-inlay expanded polytetrafluoroethylene （ePTFE） GORE-TEX Dual Mesh （WLGore And Associates, Flagstuff, USA） in abdominoperineal resection. Methods Sixty patients who underwent abdominopedneal resection for rectal cancer were assigned to 2 groups. The pelvic peritoneum was closed by routine sutures in group 1 and reconstructed with ePTFE in group 2. Postoperative complications and related items were evaluated and the patients were followed up. Results Time of confining to bed, bowel function recovery, fasting, and detaining drainage were significantly different between two groups （P 〈0.05）. In group 1, three patients developed bowel obstruction （10%）, while no bowel obstruction was observed in group 2. Conclusion Reconstruction of the pelvic floor using ePTFE results in quicker postoperative recovery and could decrease the risk of postoperative intestinal obstruction.

Transanal total mesorectal excision combined with intersphincteric resection has similar long-term oncological outcomes to laparoscopic abdominoperineal resection in low rectal cancer:a propensity score-matched cohort study

Background Transanal total mesorectal excision(taTME)or intersphincteric resection(ISR)has recently proven to be a valid and safe surgical procedure for low rectal cancer.However,studies focusing on the combination of these two technologies are limited.This study aimed to evaluate perioperative results,long-termoncologic outcomes,and anorectal functions of patients with low rectal cancer undergoing taTME combined with ISR,by comparing with those of patients undergoing laparoscopic abdominoperineal resection(laAPR).Methods After 1:1 propensity score matching,200 patients with low rectal cancer who underwent laAPR(n=100)or taTME combined with ISR(n=100)between September 2013 and November 2019 were included.Patient demographics,clinicopathological characteristics,oncological outcomes,and anal functional results were analysed.Results Patients in the taTME-combined-with-ISR group had less intraoperative blood loss(79.6672.6 vs 107.3665.1 mL,P=0.005)and a lower rate of post-operative complications(22.0%vs 44.0%,P<0.001)than those in the laAPR group.The overall local recurrence rates were 7.0%in both groups within 3 years after surgery.The 3-year disease-free survival rates were 86.3%in the taTME-combined-with-ISR group and 75.1%in the laAPR group(P=0.056),while the 3-year overall survival rates were 96.7%and 94.2%,respectively(P=0.319).There were 39 patients(45.3%)in the taTME-combined-with-ISR group who developed major low anterior resection syndrome,whereas 61 patients(70.9%)had good post-operative anal function(Wexner incontinence score≤10).Conclusion We found similar long-term oncological outcomes for patients with low rectal cancer undergoing laAPR and those undergoing taTME combined with ISR.Patients receiving taTME combined with ISR had acceptable post-operative anorectal function.

Anatomy of the lateral ligaments of the rectum: A controversial point of view

The existence and composition of the lateral ligaments of the rectum (LLR) are still the subjects of anatomical confusion and surgical misconception up to now. Since Miles proposed abdominoperineal excision as radical surgery for rectal cancer, the identification by "hooking them on the finger" has been accepted by many surgeons with no doubt; clamping, dividing and ligating are considered to be essential procedures in mobilization of the rectum in many surgical textbooks. But in cadaveric studies, many anatomists could not find LLR described by the textbooks, and more and more surgeons also failed to find LLR during the proctectomy according to the principle of total mesorectal excision. The anatomy of LLR has diverse descriptions in literatures. According to our clinical observations, the traditional anatomical structures of LLR do exist; LLR are constant dense connective bundles which are located in either lateral side of the lower part of the rectum, run between rectal visceral fascia and pelvic parietal fascia above the levator ani, and covered by superior fascia of pelvic diaphragm. They are pathways of blood vessels and nerve fibers toward the rectum and lymphatic vessels from the lower rectum toward the iliac lymph nodes.

Application of modified primary closure of the pelvic floor in laparoscopic extralevator abdominal perineal excision for low rectal cancer

AIM To introduce a novel,modified primary closure technique of laparoscopic extralevator abdominal perineal excision(LELAPE) for low rectal cancer.METHODS We retrospectively analyzed data from 76 patients with rectal cancer who underwent LELAPE from March 2013 to May 2016.Patients were classified into the modified primary closure group(32 patients) and the biological mesh closure group(44 patients).The total operating time,reconstruction time,postoperative stay duration,total cost,postoperative complications and tumor recur-rence were compared.RESULTS All surgery was successfully performed.The pelvic reconstruction time was 14.6 ± 3.7 min for the modified primary closure group,which was significantly longer than that of the biological mesh closure group(7.2 ± 1.9 min,P < 0.001).The total operating time was not different between the two groups(236 ± 20 min vs 248 ± 43 min,P = 0.143).The postoperative hospital stay duration was 8.1 ± 1.9 d,and the total cost was 9297 ± 1260 USD for the modified primary closure group.Notably,both of these categories were significantly lower in this group than those of the biological mesh closure group(P = 0.001 and P = 0.003,respectively).There were no differences observed between groups when comparing other perioperative data,long-term complications or oncological outcomes.CONCLUSION The modified primary closure method for reconstruction of the pelvic floor in LELAPE for low rectal cancer is technically feasible,safe and cost-effective.

Systematic review of oncological outcomes following laparoscopic vs open total mesorectal excision

AIM: To systematically analyze the randomized trials comparing the oncological and clinical effectiveness of laparoscopic total mesorectal excision(LTME) vs open total mesorectal excision(OTME) in the management of rectal cancer.METHODS: Published randomized, controlled trials comparing the oncological and clinical effectiveness of LTME vs OTME in the management of rectal cancer were retrieved from the standard electronic medical databases. The data of included randomized, controlled trials was extracted and then analyzed according to the principles of meta-analysis using RevMan? statistical software. The combined outcome of the binary variables was expressed as odds ratio(OR) and the combined outcome of the continuous variables waspresented in the form of standardized mean difference(SMD). RESULTS: Data from eleven randomized, controlled trials on 2143 patients were retrieved from the electronic databases. There was a trend towards the higher risk of surgical site infection(OR = 0.66; 95%CI: 0.44-1.00; z = 1.94; P < 0.05), higher risk of incomplete total mesorectal resection(OR = 0.62; 95%CI: 0.43-0.91; z = 2.49; P < 0.01) and prolonged length of hospital stay(SMD,-1.59; 95%CI:-0.86--0.25; z = 4.22; P < 0.00001) following OTME. However, the oncological outcomes like number of harvested lymph nodes, tumour recurrence and risk of positive resection margins were statistically similar in both groups. In addition, the clinical outcomes such as operative complications, anastomotic leak and all-cause mortality were comparable between both approaches of mesorectal excision.CONCLUSION: LTME appears to have clinically and oncologically measurable advantages over OTME in patients with primary rectal cancer in both short term and long term follow ups.

Risk factors for adverse outcome in low rectal cancer

AIM: To demonstrate the oncologic outcomes of low rectal cancer and to clarify the risk factors for survival, focusing particularly on the type of surgery performed. METHODS: Data from patients with low rectal carcinomas who underwent surgery, either sphincter-preserving surgery (SPS) or abdominoperineal resection (APR), at The First Aff iliated Hospital of Sun Yat-sen University in China from August 1994 to December 2005 were retrospectively analyzed. RESULTS: Of 331 patients with low rectal cancer, 159 (48.0%) were treated with SPS. A higher incidence of positive resection margins and a higher 5-year cumulative local recurrence rate (14.7% vs 6.8%, P = 0.041) were observed in patients after APR compared to SPS.The five-year overall survival (OS) was 54.6% after APR and 66.8% after SPS (P = 0.018), and the 5-year disease-free survival (DFS) was 52.9% after APR and 65.5% after SPS (P = 0.013). In multivariate analysis, poor OS and DFS were signif icantly related to positive resection margins, pT3-4, and pTNM Ⅲ-Ⅳ but not to the type of surgery. CONCLUSION: Despite a higher rate of positive resection margins after APR, the type of surgery was not identif ied as an independent risk factor for survival.

Laparoscopic abdomino-perineal resection for patients with anorectal malignant melanoma:a report of 4 cases

Anorectal malignant melanoma is a very rare but lethal disease. Patients with anorectal malignant melanoma commonly complain for changes in bowel habits and rectal bleeding. Therefore, anorectal malignant melanoma is often misdiagnosed as hemorrhoids, polyp or rectal cancer. Surgery is the mainstay of treatment for patients with anorectal malignant melanoma. However, whether abdominoperineal resection or wide local excision is the most appropriate surgical approach is still a controversial issue. Recently, with the great development of laparoscopic techniques, more and more operations can be performed by laparoscopic techniques. However, laparoscopic abdominoperineal resection for management of anorectal malignant melanoma has been rarely reported. In this study, we reported 4 patients with anorectal malignant melanoma underwent laparoscopic abdominoperineal resection. The outcomes of these patients were relatively good during a long time follow-up. Meanwhile, we reviewed the relevant studies with particular focus surgical treatment.

Retrorectal tumors:A challenge for the surgeons

Retrorectal or presacral tumors are rare lesions located in the presacral area and considered as being derived from multiple embryological remnants.These tumors are classified as congenital,neurogenic,osseous,inflammatory,or miscellaneous.The most common among these are congenital benign lesions that present with non-specific symptoms,such as lower back pain and change in bowel habit.Although congenital and developmental tumors occur in younger patients,the median age of presentation is reported to be 45 years.Magnetic resonance imaging plays a crucial role in treatment management through accurate diagnosis of the lesion,the evaluation of invasion to adjacent structures,and the decision of appropriate surgical approach.The usefulness of preoperative biopsy is still debated;currently,it is only indicated for solid or heterogeneous tumors if it will alter the treatment management.Surgical resection with clear margins is considered the optimal treatment;described approaches are transabdominal,perineal,combined abdominoperineal,and minimally invasive.Benign retrorectal tumors have favorable long-term outcomes with a low incidence of recurrence,whereas malignant tumors have a potential for distant organ metastasis in addition to local recurrence.

肛提肌外腹会阴联合切除术的关键解剖和“两平面四边界”的手术原则

腹会阴联合切除术（APR）为目前治疗低位直肠癌的主要手术方式.最近研究发现,传统的APR存在较高的标本环周切缘（CRM）阳性率和术中穿孔率（IOP）,并被认为是导致APR术后局部复发和预后差的重要原因.肛提肌外腹会阴联合切除术（ELAPE）是由欧洲外科学家、影像学家和病理学家共同倡导的一种认为可降低环周切缘阳性率和术中穿孔率的新术式.明确的操作平面和解剖学边界是该术式的核心内容,也是确保手术安全及顺利实施的前提;而了解会阴区直肠周围的肌肉、筋膜和血管和神经解剖是开展该手术的基础.本文就ELAPE手术中所涉及的关键解剖进行了介绍,并将ELAPE手术操作要点归纳为“两平面、四边界”原则,以利于该术式的推广和应用。