INTRODUCTION Bladder cancer (BCa) is the 10th most common malignancy according to the latest global cancer statistics, with an estimated 549,000 new cases and 199,000 deaths occurring per year(1). Approximately 25% of patients with primary BCa have been diagnosed with muscle invasive bladder cancer (MIBC), and ap- proximately 10-30% of non-muscle invasive bladder cancer (NMIBC) can progress to MIBC(2,3). Accord- ingly, the treatment of BCa is of great importance for urologists. Radical cystectomy (RC) with extended pelvic lym- phadenectomy is the guideline-recommended treatment for high-risk NMIBC and MIBC(4,5). Open RC (ORC) is considered one of the most invasive surgeries in urol- ogy and has serious perioperative complications(6,7). Following rapid technical advances, laparoscopic rad- ical cystectomy (LRC) has been widely accepted be- cause of its minimal invasiveness, lower blood loss, and shorter hospital stay, while yielding equivalent or better outcomes for patients relative to ORC(8-10). Fur- thermore, one of the most important advantages of LRC is the lower incidence of postoperative ileus, which is the most frequent complication after cystectomy and a common reason for longer hospital stays(11). LRC also achieves better hemostasis due to pneumoperitoneum and precise visibility when performing the technique. However, the technical procedure for LRC is compli- cated, and the surgeon should have an excellent under- standing of the pelvic anatomy. LRC is still a challenge due to the longer operation time and the need to estab- lish pneumoperitoneum, especially for elderly or higher BMI patients(12). It is difficult to perform surgical ma- nipulations in the insufficient operative space. Thus, it is important to understand the pelvic anatomy precisely and improve the surgical procedure to decrease the in- cidence of complications and operating time in LRC. LAPAROSCOPIC AND ROBOTIC UROLOGY “Two-zone and Three-segment” Laparoscopic Radical Cystectomy vs Conventional Laparoscopic Radical Cystectomy for Male Patients With Bladder Urothelial Carcinoma: A Retrospective Analysis Shouzhen Chen1,2#, Jianfeng Cui1,2#, Haoyu Sun1,2, Wenfu Wang1,2, Xigao Liu1,2, Dongqing Zhang1,2, Xianzhou Jiang1,2, Hu Guo1,2, Nianzeng Xing3,4, Yaofeng Zhu1,2**, Benkang Shi1,2* Purpose: The aim of this study was to introduce an advanced surgical technique for laparoscopic radical cystecto- my (LRC), evaluate the perioperative outcome and compare it to that of conventional LRC (CLRC). Materials and Methods: Between March 2018 and March 2020, sixty patients were divided into the “two-zone and three-segment” laparoscopic radical cystectomy (TTLRC) group or the CLRC group. Patient baseline charac- teristics, preoperative characteristics and postoperative complications were collected. Results: The TTLRC technique was developed based on the pelvic anatomy of six formalin fixed male cadavers. None of the patient baseline characteristics, including ECOG-PS score, comorbidity, ASA score and Hb, were sig- nificantly different between the two groups (p > 0.05). There were significant differences in the operating time and estimated blood loss (total time: 3±0.2 vs 3.8 ± 0.4, p < 0.001; time to cystectomy and lymph node dissection: 1.7 ± 0.2 vs 2.2 ± 0.3, p < 0.001; estimated blood loss 182. 1± 18.8 vs 264.3 ± 27.4, p < 0.001). Although there were no differences in late complications, early complications were significantly different between the two groups (p = 0.033). No statistically significant differences were found between the two groups in other outcomes (p > 0.05). Conclusion: The TTLRC technique achieves a clearer surgical field, has a shorter operating time and produces less blood loss than CLRC. It is safe and feasible for urologists to perform this improved LRC procedure. Keywords: laparoscopic radical cystectomy; bladder cancer; outcome; complication; surgical technique 1Department of Urology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China. 2Key Laboratory of Urinary Precision Diagnosis and Treatment in Universities of Shandong, Jinan, 250012, China. 3Department of Urology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 17, Panjiayuan South Li, Chaoyang District, Bei- jing, 100021, China. 4Department of Urology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100020, China. *Correspondence: Department of Urology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shan- dong, 250012, China. E-mail: bkang68@sdu.edu.cn. ** Department of Urology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, China. E-mail: feng2209@163.com. #Shouzhen Chen and Jianfeng Cui are equal to this article. Received July 2021 & Accepted December 2021 Urology Journal/Vol 19 No. 1/ January-February 2022/ pp. 34-40. [DOI: 10.22037/uj.v19i.6919] Vol 19 No 1 January-February 2022 138 Herein, we performed an advanced surgery technique for LRC based on our pelvic anatomy research, named “two-zone and three-segment” laparoscopic radical cystectomy (TTLRC). We conducted a retrospective analysis to evaluate the efficiency and safety of TTLRC and compare it to conventional LRC (CLRC). MATERIALS AND METHODS Patients Patients who met the following conditions were exclud- ed from this study: (1) any distant metastases; (2) auto- Figure 1. Schematic model of “two-zone and three-segment” laparoscopic radical cystectomy. (A) Lateral view. (B) Anterior view. Variables Total (n=60) TTLRC (n=29) CLRC (n=31) P-value Age, year (mean ± SD) a 64.7 ± 10.9 65.3 ± 11.9 64.1 ± 10.0 0.668 History of smoking, n (%) 20 (33.3) 10 (34.5) 10 (32.3) 0.536 BMI (kg/m2) (mean ± SD) b 24.1 ± 3.3 24.0 ± 3.3 24.1 ± 3.3 0.777 ECOG-PS score, n (%) 0.281 0 56 (93.3) 26 (89.7) 30 (96.8) ≥1 4 (6.7) 3 (10.3) 1 (3.2) Comorbidity, n (%) 0.881 Hypertension 19 (31.7) 8 (27.6) 11 (35.5) Diabetes mellitus 14 (23.3) 7 (24.1) 7 (22.6) Coronary artery disease 10 (16.7) 6 (20.7) 4 (12.9) Chronic obstructive pulmonary disease 7 (11.7) 3 (10.3) 4 (12.9) Others 3 (5.0) 1 (3.4) 2 (6.5) ASA score, n (%) 0.538 1-2 53 (88.3) 26 (89.7) 27 (87.1) 3 7 (11.7) 3 (10.3) 4 (12.9) Hb (g/L) b 122 ± 7.1 122.3 ± 7.0 121.6 ± 7.2 0.880 Clinical stage, n (%) 0.538 NMIBC 16 (26.7) 8 (27.6) 8 (25.8) MIBC 44 (73.3) 21 (72.4) 23 (74.2) Clinical tumor grade, n (%) 0.586 Low 8 (13.3) 4 (13.8) 4 (12.9) High 48 (80.0) 24 (82.6) 24 (77.4) Squamous cell carcinoma 2 (3.3) 0 (0) 2 (6.5) Adenocarcinoma 2 (3.3) 1 (3.4) 1 (3.2) Table 1. Patient Demographics and Tumor Characteristics Abbreviations: TTLRC, “Two-zone and Three-segment” Laparoscopic Radical Cystectomy; CLRC, Conventional Laparoscopic Radical Cystectomy; SD, Standard Deviation; BMI, Body Mass Index; ECOG-PS, Eastern Cooperative Oncology Group performance Status; Hb, Hemoglobin; NMIBC, Non-Muscle Invasive Bladder Cancer; MIBC, Muscle Invasive Bladder Cancer a These variables were compared by independent samples t-test b These variables were compared by Mann-Whitney test TTLRC vs CLRC in bladder cancer-Chen et al. Vol 19 No 1 January-February 2022 35 Laparoscopic and Robotic Urology 36 immune disease; (3) cancer in other systems; (4) Amer- ican Society of Anesthesiology (ASA) grade > 3; (5) clinical stage T4; (6) previous pelvic radiotherapy; and (7) severe cardiopulmonary dysfunction preventing sur- gical tolerance. This retrospective analysis included the clinicopathologic and follow-up data of 60 patients with high-risk NMIBC, MIBC or other types of BCa in Qilu Hospital of Shandong University from March 2018 to March 2020. All patients were divided into 2 groups; 29 patients in the TTLRC group and 31 in the CLRC group. None of the patients had neoadjuvant chemo- therapy or radiotherapy. Patients with lymph node-pos- itive disease or locally advanced disease were treated with adjuvant chemotherapy. This study was approved by the Institutional Ethics Committee of the Qilu Hos- pital of Shandong University. Written informed consent was obtained from all the patients in this study. All patients underwent routine laboratory tests, echo- cardiography, lung function tests, chest radiographs, computerized tomography (CT), magnetic resonance imaging (MRI), urinary cytology and / or cystoscopy with tissue biopsy. All operations and perioperative management were performed by the same laparoscop- ic surgical team. All three surgeons (BK, XZ and DQ) in this study are well-experienced in performing LRC. BK performed 18 and 16, XZ performed 7 and 9, and DQ performed 4 and 6 TTLRC and CLRC procedures, respectively. Conventional laparoscopic radical cystectomy The basic procedures were performed as reported by Campbell-Walsh Urology(13). The patient was placed in a dorsal supine position with a 15 - 25° Trende- lenburg position after general anesthesia. A five-port fan-shaped approach was used. The camera port was placed just above the umbilicus after establishment of pneumoperitoneum and the remaining four ports were placed in a fan shape. Standard lymphadenectomy was first conducted after releasing the ureter. Then, the pos- terior wall of the bladder was separated. The lateral lig- aments of the bladder were dissected (Figure 1A). The anterior plane was then established distally toward the prostate (Figure 1B). The attachments of the prostatic apex to the pelvic floor were released, and the urethral catheter was removed. After dissection of the Santorini venous plexus, the urethra was dissected. After lapa- roscopic cystectomy, urinary diversion, was performed with procedures such as the Bricker operation of uret- erocutaneostomy according to the patient’s preference. “Two-zone and three-segment” laparoscopic radical TTLRC vs CLRC in bladder cancer-Chen et al. Variables Total (n=60) TTLRC (n=29) CLRC (n=31) P-value Operating time, hours (mean±SD) Total timea 3.4 ± 0.5 3.0 ± 0.2 3.8 ± 0.4 < 0.001 Time to cystectomy and lymph node dissectiona 1.9 ± 0.4 1.7 ± 0.2 2.2 ± 0.3 < 0.001 EBL, ml (mean±SD) a 224.6 ± 47.6 182.1 ± 18.8 264.3 ± 27.4 < 0.001 Pelvic lymph node dissection, n (%) 0.538 Standard 53 (88.3) 26 (89.7) 27 (87.1) Extended 7 (11.7) 3 (10.3) 4 (22.9) Urinary diversion type, n (%) 0.424 Ureterocutaneostomy 4 8 (80.0) 24 (82.8) 24 (77.4) Ileal conduit 12 (20.0) 5 (17.2) 7 (22.6) Transfusion, n (%) 8 (13.3) 2 (6.9) 6 (19.4) 0.15 Time to ambulation, day, median (range) 2 (2-4) 2 (2-4) 2 (2-4) 0.764 Time to oral intake, day, median (range) 3 (2-5) 2 (2-4) 3 (2-5) 0.409 Time to flatus, day, median (range) 2 (2-4) 2 (2-4) 2 (2-4) 0.803 Hospital stay after surgery, day, median (range) 5 (4-9) 5 (4-6) 7 (4-9) < 0.001 Table 2. Perioperative characteristics. Abbreviations: TTLRC, “Two-zone and Three-segment” Laparoscopic Radical Cystectomy; CLRC, Conventional Laparoscopic Radical Cystectomy; SD, Standard Deviation; EBL, Estimated Blood Loss; min, Minute a These variables were compared by Mann-Whitney test Variables Total (n=60) TTLRC (n=29) CLRC (n=31) P-value pT stage, n (%) 0.631 Cis 2 (3.3) 1 (3.4) 1 (3.2) Ta/T1 7 (11.7) 3 (10.3) 4 (12.9) T2 26 (43.3) 10 (34.5) 16 (51.6) T3 16 (26.7) 10 (34.5) 6 (19.4) T4 9 (15.0) 5 (17.2) 4 (12.9) Pathological tumor grade, n (%) 0.327 Low 11 (18.3) 4 (13.9) 7 (22.6) High 44 (73.3) 24 (82.8) 20 (64.5) Squamous cell carcinoma 2 (3.3) 0 (0) 2 (6.5) Adenocarcinoma 3 (5.0) 1 (3.4) 2 (6.5) Concomitant Cis, n (%) 5 (8.3) 3 (10.3) 2 (6.5) 0.666 pN stage, n (%) 0.608 pN0 52 (86.7) 25 (86.2) 27 (87.1) pN+ 8 (13.3) 4 (13.8) 4 (12.9) Table 3. Pathological characteristics. Abbreviations: TTLRC, “Two-zone and Three-segment” Laparoscopic Radical Cystectomy; CLRC, Conventional Laparoscopic Radi- cal Cystectomy; CIS, Carcinoma in Situ Vol 19 No 1 January-February 2022 138 cystectomy The “two-zone and three-segment” laparoscopic radical cystectomy technique was developed based on the pel- vic anatomy. Six formalin-fixed male cadavers, which were provided by the Institute of Anatomy, Shandong University, were used to conduct anatomical studies. According to the anatomical characteristics of the lat- eral vascular pedicles of the bladder, we defined 3 seg- ments: the superior bladder artery segment, the bladder vein segment, and the inferior bladder artery segment (Figure 2A). The inferior bladder artery segment is also called the prostatic vascular pedicle segment. “Two-zone and three-segment” laparoscopic radical cystectomy was performed as follows. The umbilical artery was first identified after releasing the ureter. The umbilical artery lateral plane was established distally toward the pelvic floor, an important procedure of this technique. On the interior side of the plane was the “lat- eral vascular pedicles of bladder” zone, while on the opposite side of the plane was the “lymph node dis- section” zone (Figure 2B). Standard pelvic lymphad- enectomy was performed in the areas of the common, external and internal iliac arteries and the obturator. The superior bladder artery segment and the bladder vein segment were dissected (Figure 2C-D). Mobilization of the posterior wall of the bladder was performed. Then, the inferior bladder artery segment was dissect- ed. The next steps were the same as in the conventional methods. Demographic parameters and follow-up The following demographic parameters were recorded and analyzed by clinical researchers with no association with the operations (JF and SZ): preoperative baseline clinicopathological and laboratory data, such as age, gender, history of smoking, BMI, clinical tumor stage, and hemoglobin, were obtained from the electronic medical records. Perioperative data, including operation time, estimated blood loss (EBL), blood transfusion, urinary diversion method, time to ambulation, time to bowel recovery, time to oral intake and hospital stay, and oncologic data, including pathologic tumor stage, grade and lymph node metastasis status, were also as- sessed. Operation time was defined as the duration of anesthesia from the beginning to the end. Pathological T stages were uniformly adjusted according to the 2009 TNM classification as approved by the Union Interna- tionale Contre le Cancer (7th edition), and tumor grade was assessed based on the 2004 World Health Organi- zation (WHO) classification guidelines(2,4). Laparoscopic and Robotic Urology 506 Figure 2. The “two-zone and three-segment” laparoscopic radical cystectomy techinique. (A) Anatomical picture of the lateral vascular pedicles of the bladder, which consists of three segments: I, the superior bladder artery segment; II, the bladder vein segment; and III, the inferior bladder artery segment. (B) Laparoscopic image showing the two zones: I, the lateral vascular bladder pedicle zone; and II, the lymph node dissection zone. III represents the umbilical artery, and IV represents the umbilical artery lateral plane, which was the bound- ary between the two zones. (C) Dissecting the superior bladder artery segment. (D) Dissecting the bladder vein segment. (E) Dissecting the inferior bladder artery segment. TTLRC vs CLRC in bladder cancer-Chen et al. Vol 19 No 1 January-February 2022 37 Postoperative complications were recorded and catego- rized using the modified Clavien-Dindo classification complications system introduced by Dindo D et al.(14), which includs five groups and two subgroups. Compli- cations were classified as early complications (within 30 days) and late complications (31-90 days). Common comorbidities were also recorded in detail, including hypertension, diabetes mellitus, coronary ar- tery disease, chronic obstructive pulmonary disease and other chronic diseases. Patients were followed postoperatively at least every 3–4 months for the first 2 years, biannually for the next three years, and annually thereafter. Postoperative com- plication data were obtained by either chart review or telephone contact follow-up. This research complied with the guidelines for human studies and the research was conducted ethically in ac- cordance with the World Medical Association’s Decla- ration of Helsinki. The research was approved by Ethics Committee of Shandong University Qilu Hospital. Ap- proved number: KYLL-2020-264 Statistical analysis Statistical analysis was conducted using the Statistical Package for Social Science (SPSS for Windows, ver- sion 23.0, SPSS Inc., Chicago, IL) software. Quantita- tive data are shown as the mean ± SD, and categorical data are presented as the frequency (%). Pearson’s chi square test or Fisher’s exact test was used to evaluate the differences between categorical variables, student’s t test (meet the normality of distribution and homoge- neity) and Mann-Whitney test (meet the nonparametric test) were used for continuous variables in this study. Two-sided P values of less than 0.05 were considered statistically significant. RESULTS Patient characteristics The baseline characteristics are shown in Table 1. Of the 63 patients who underwent LRC at our institution from March 2018 to March 2020, 3 patients were ex- cluded because of exclusion criteria. The mean (SD) age of the total patients was 64.7 (10.9), and among the 60 patients, 20 (33.3%) had a history of smoking. The mean (SD) body mass index (BMI) was 24.1 (3.3). Sixteen patients (26.7%) were clinically diagnosed with NMIBC, and 44 (73.3%) were clinically diag- nosed with MIBC. A low tumor grade was found in 8 patients (13.3%), and a high tumor grade was found in 48 (80.0%). The median (lower quartile, upper quartile) duration of follow-up was 26 (19.75, 31.25). None of the patient clinical characteristics, including ECOG-PS score, comorbidity, ASA score and Hb, were signifi- cantly different between the TTLRC and CLRC groups (P > .05). Perioperative characteristics The perioperative characteristics of the two groups are shown in Table 2. The operating time of the TTLRC group was significantly shorter than that of the CLRC group (total time: 3.0 ± 0.2 vs 3.8 ± 0.4, P < .001; time to cystectomy and lymph node dissection: 1.7 ± 0.2 vs 2.2 ± 0.3, P < .001). Additionally, the EBL of the TTLRC group was significantly lower than that of the CLRC group (182.1 ± 18.8 vs 264.3 ± 27.4). Fifty-three patients (88.3%) underwent standard pelvic lymph node dissection, and 7 (11.7%) underwent extend- ed pelvic lymph node dissection. Forty-eight patients (80.0%) underwent LRC with ureterocutaneostomy and 12 (20.0%) underwent LRC with ileal conduits. More- over, except for hospital stay after surgery, there were no significant differences between the two groups in the transfusion rate, time to ambulation, time to oral intake or time to flatus. The pathological characteristics of the patients are shown in Table 3. Both the TTLRC and CLRC groups included one patient with CIS each, and 5 patients were found to have concomitant CIS, 3 and 2 in the TTLRC and CLRC groups, respectively. No significant differ- ences were found in pathological T stage, tumor grade or N stage (P > .05). Postoperative complications The early and late postoperative complications of the two groups are shown in Table 4. During the follow-up period, only one death occurred in both groups. Accord- ing to the Clavien-Dindo classification of postoperative Laparoscopic and Robotic Urology 38 Table 4. Complications characteristics by Clavien-Dindo classification. Variables Total (n = 60) TTLRC (n = 29) CLRC (n = 31) Clavien-Dindo classification P-value Early complications (≤ 30 day), n (%) 0.033 Paralytic ileus 8 (13.3) 2 (6.9) 6 (19.4) I Anemia 7 (11.7) 2 (6.9) 5 (16.1) II Hypokalemia 4 (6.7) 2 (6.9) 2 (6.5) II Urinary tract infection 3 (5.0) 1 (3.4) 2 (6.5) II Blood transfusions 2 (3.3) 1 (3.4) 1 (3.2) II Entorrhagia 4 (6.7) 2 (6.9) 2 (6.5) III Rectal injury 4 (6.7) 1 (3.4) 3 (9.7) III Acute coronary syndrome 3 (5.0) 1 (3.4) 2 (6.5) IV Heart failure 2 (3.3) 1 (3.4) 1 (3.2) IV Late complications (31-90 day), n (%) 0.729 Hydronephrosis 4 (6.7) 2 (6.9) 2 (6.5) I Pyelonephritis 3 (5.0) 1 (3.4) 2 (6.5) II Urinary tract infection 5 (8.3) 2 (6.9) 3 (9.7) II Pneumonia 5 (8.3) 2 (6.9) 3 (9.7) II Deep venous thrombosis 1 (1.7) 1 (3.4) 0 (0.0) II Ureteral stricture 2 (3.3) 1 (3.4) 1 (3.2) III Urolithiasis 3 (5.0) 2 (6.9) 1 (3.2) III Renal failure 2 (3.3) 1 (3.4) 1 (3.2) III Death 1 (1.7) 0 (0.0) 1 (3.2) V TTLRC vs CLRC in bladder cancer-Chen et al. Vol 19 No 1 January-February 2022 39 complications, thirty-seven patients (61.7%) experi- enced early complications. Eight and 16 minor (I-II) complications and 5 and 8 major (III-IV) complications were observed in the TTLRC and CLRC groups, re- spectively. The common complications were paralytic ileus and anemia. There was a significant significance between the two groups in early complications (I-II vs III-IV, P = .033), not in late complications (I-II vs III- IV, P = .729). DISCUSSION Radical cystectomy is one of the most difficult urologi- cal surgeries, and the LRC procedure is difficult to mas- ter and technically challenging. Most patients with BCa are elderly males whose pelvis is narrow, which could increase the difficulties of surgery. The present study is the first paper comparing TTLRC and CLRC in male patients. These operations were performed by the same laparoscopic surgical team, including three surgeons, in a single center. We used 6 male cadavers to conduct pelvic anatomi- cal research and developed the improved TTLRC tech- nique. There were variations in the superior vesical artery segment among the cadavers. Most superior ves- ical arteries are derived from the umbilical artery, and a few are derived from the internal iliac artery directly. Therefore, it is important to expose bladder-associated vessels, such as the superior vesical artery, umbilical artery, and obturator artery. It is also important for ex- perienced surgeons to learn the anatomy from cadavers. A more detailed evaluation of anatomy has allowed a better understanding of the variability of vessels, pre- vents disruption of vessels, and helps guide the opera- tional procedure. In the TTLRC group, the bladder vein segment, including the many branches derived from the bladder vein and part of the large veins, was the most common bleeding site in LRC surgery. A LigaSure or endovascular gastrointestinal anastomosis (Endo-GIA) stapler was used to rapidly dissect this segment to short- en the operating time. Moreover, for male patients who desire retention of erectile function, we should avoid thermal damage to preserve the neurovascular bundles (NVBs), which is another important step for the pa- tients. Tong et al. reported the anterior approach LRC could modify the laparoscopic visualization and enlarge the working space. This procedure also reduces the oper- ation time and EBL without causing substantial differ- ences in perioperative complications(15). Additionally, compared with CLRC, the extraperitoneal LRC tech- nique resulted in a shorter time to flatus and time to liquid intake but had no benefit on operation time(16). In the present study, the TTLRC group showed benefits in early complications and perioperative outcome, includ- ing operating time, time to cystectomy and lymph node dissection and EBL. From our study, there were several surgical benefits for the TTLRC group. First, we divid- ed the surgical location into two zones to dissect the vessels and lymph nodes separately, which improved visualization of the anatomical hierarchies. Moreover, for patients of older age or moderate comorbidity sta- tus, a modified surgery in which only the bladder was dissected while the lymph nodes were left intact was conducted to shorten the operating time and further re- duce the risk of surgery. Last, we defined the male blad- der-associated region, and systematically introduced a TTLRC vs CLRC in bladder cancer-Chen et al. surgical procedure that could be useful for laparoscop- ic-naive urologists. Urinary diversion approaches can be divided into uret- erocutaneostomy, ileal conduit and orthotopic neoblad- der. In addition, most of the complications are related to the use of the bowel. Ureterocutaneostomy is the simplest form of diversion and has a lower complica- tion rate(17). Here, the incidence of ileus was lower in patients who underwent ureterocutaneostomy than in those described in other studies(18). Ureterocutaneos- tomy was performed in more patients in the TTLRC group, which might be a potential factor influencing the shorter operation time. Furthermore, extended lymph node dissection and ileal conduit diversion were per- formed more often in the CLRC group, which also might have affected the operation time. There are a few limitations in this study. First, patients were recruited from a single center in this study, which could have caused selection bias. Second, the sample size was small, and future studies should include an en- larged sample size. Third, this is a retrospective study, not a randomized controlled trial, which is needed to improve the power in drawing a definitive conclusion in a future study. Last, a comparison of the long-term clinical outcomes between TTLRC and CLRC should be collected and analyzed in future studies. CONCLUSIONS In conclusion, we studied the pelvic anatomy based on cadavers, and defined the zones and segments used for surgery to develop the “two-zone and three-segment” LRC procedure, whose outcomes were compared with conventional LRC. Compared with CLRC, TTLRC has several advantages, including a clearer surgical field, a shorter operating time and less blood loss. It is safe and feasible for urologists to perform this improved LRC procedure. ACKNOWLEDGMENTS This study was supported by the National Natural Sci- ence Foundation of China (Grant No. 81900637 to BK.Shi, Grant No. 81800672 to SZ Chen), the Tai Shan Scholar Foundation (ts201511092 to BK Shi) and Pri- mary Research & Development Plan of Shandong Prov- ince (2019GSF108123 to SZ Chen). CONFLICTS OF INTEREST The authors have declared that no conflicts of interest exist. REFERENCES 1. Bray F, Ferlay J, Soerjomataram I, Siegel RL, Torre LA, Jemal A. Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin. 2018;68:394- 424. 2. Soukup V, Čapoun O, Cohen D, et al. Prognostic Performance and Reproducibility of the 1973 and 2004/2016 World Health Organization Grading Classification Systems in Non-muscle-invasive Bladder Cancer: A European Association of Urology Non-muscle Invasive Bladder Cancer Guidelines Panel Systematic Review. Eur Urol. 2017;72:801- 13. 3. Abufaraj M, Dalbagni G, Daneshmand S, et al. The Role of Surgery in Metastatic Bladder Cancer: A Systematic Review. Eur Urol. 2018;73:543-57. 4. Alfred Witjes J, Lebret T, Compérat EM, et al. Updated 2016 EAU Guidelines on Muscle- invasive and Metastatic Bladder Cancer. Eur Urol. 2017;71:462-75. 5. Williams SB, Shan Y, Jazzar U, et al. Comparing Survival Outcomes and Costs Associated With Radical Cystectomy and Trimodal Therapy for Older Adults With Muscle-Invasive Bladder Cancer. JAMA Surg. 2018;153:881-9. 6. Tang K, Xia D, Li H, et al. Robotic vs. open radical cystectomy in bladder cancer: A systematic review and meta-analysis. Eur J Surg Oncol. 2014;40:1399-411. 7. Cao Q, Li P, Yang X, et al. Laparoscopic radical cystectomy with pelvic re-peritonealization: the technique and initial clinical outcomes. BMC Urol. 2018;18:113. 8. Novara G, Catto JW, Wilson T, et al. Systematic review and cumulative analysis of perioperative outcomes and complications after robot-assisted radical cystectomy. Eur Urol. 2015;67:376-401. 9. Sathianathen NJ, Kalapara A, Frydenberg M, et al. Robotic Assisted Radical Cystectomy vs Open Radical Cystectomy: Systematic Review and Meta-Analysis. J Urol. 2019;201:715-20. 10. Bochner BH, Dalbagni G, Sjoberg DD, et al. Comparing Open Radical Cystectomy and Robot-assisted Laparoscopic Radical Cystectomy: A Randomized Clinical Trial. Eur Urol. 2015;67:1042-50. 11. Novotny V, Hakenberg OW, Wiessner D, et al. Perioperative complications of radical cystectomy in a contemporary series. Eur Urol. 2007;51:397-401; discussion -2. 12. Zeng S, Zhang Z, Yu X, et al. Laparoscopic versus open radical cystectomy for elderly patients over 75-year-old: a single center comparative analysis. PLoS One. 2014;9:e98950. 13. Mann U, Ramjiawan R, Nayak JG, Patel P. Heterogeneity in urology teaching curricula among Canadian urology residency programs. Can Urol Assoc J. 2021;15:E41-e7. 14. Dindo D, Demartines N, Clavien PA. Classification of surgical complications: a new proposal with evaluation in a cohort of 6336 patients and results of a survey. Ann Surg. 2004;240:205-13. 15. Tong S, Yang Z, Zu X, et al. Anterior versus posterior approach laparoscopic radical cystectomy: a retrospective analysis. World J Surg Oncol. 2019;17:9. 16. Feng L, Song J, Wu M, Tian Y, Zhang D. Extraperitoneal versus transperitoneal laparoscopic radical cystectomy for selected elderly bladder cancer patients: a single center experience. Int Braz J Urol. 2016;42:655-62. 17. Longo N, Imbimbo C, Fusco F, et al. Complications and quality of life in elderly patients with several comorbidities undergoing cutaneous ureterostomy with single stoma or ileal conduit after radical cystectomy. BJU Int. 2016;118:521-6. 18. Li J, Yang F, He Q, Wang M, Xing N. Laparoscopic radical cystectomy with intracorporeal ileal conduit: one center experience and clinical outcomes. Int Braz J Urol. 2019;45:560-71. TTLRC vs CLRC in bladder cancer-Chen et al. Laparoscopic and Robotic Urology 40