Incidence and risk factors of inguinal hernia after robot-assisted radical prostatectomy: a retrospective multicenter cohort study in Japan (the MSUG94 group)

Incidence and risk factors of inguinal hernia after robot-assisted radical prostatectomy: a retrospective multicenter cohort study in Japan (the MSUG94 group) | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Incidence and risk factors of inguinal hernia after robot-assisted radical prostatectomy: a retrospective multicenter cohort study in Japan (the MSUG94 group) Masahiro Toide, Shin Ebara, Tomoyuki Tatenuma, Yoshinori Ikehata, and 13 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3153830/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 17 Jan, 2024 Read the published version in Journal of Robotic Surgery → Version 1 posted 7 You are reading this latest preprint version Abstract Purpose: To investigate the incidence and risk factors of inguinal hernia (IH) after robot-assisted radical prostatectomy (RARP) using a multicentric database. Methods: The present study used a multicentric database (the MSUG94) containing data on 3,195 Japanese patients undergoing RARP between 2012 and 2021. Surgical procedures utilized for IH prevention were as follows: isolation of the vas deferens, transection the vas deferens, isolation of the spermatic vessels, and separation of the peritoneum from the internal inguinal ring. The primary and secondary endpoints were IH-free survival and any association between post-RARP IH and clinical covariates. The prophylactic effect of the above procedures were also assessed. Results: IH prevention was attempted in 1,465 (46.4%) patients at five of the nine hospitals. During follow-up (median 24 months), post-RARP IH developed in 243 patients. The post-RARP IH-free survival rate at year 1, 2, and 3 was 94.3%, 91.7%, and 90.5%, respectively. Old age (hazard ratio [HR]: 1.037; 95% confidence interval [CI]: 1.014-1.061; p = 0.001), low BMI (HR: 0.904; 95% CI: 0.863-0.946: p <0.001), and low hospital volume (HR: 1.385; 95% CI: 1.003-1.902; p = 0.048) were independently associated with IH development. None of the procedures for IH prevention were associated with IH development. Conclusion: Our findings may represent the current, real-world status of post-RARP IH in Japan. The prophylactic effects of the surgical procedures for IH prevention should be further investigated in well-designed, prospective studies to optimize the surgical technique. Inguinal hernia Multicenter study Prostate cancer Radical prostatectomy Robot-assisted radical prostatectomy Figures Figure 1 Introduction Prostate cancer is one of the most common types of cancer in men worldwide, and the radical prostatectomy is the standard of care for localized prostate cancer [ 1 , 2 ]. Surgical approaches have changed from open to laparoscopic surgery and then to robot-assisted laparoscopic surgery. The robot-assisted radical prostatectomy (RARP) is now widely used and more commonly performed in the United States than the open retropubic radical prostatectomy (ORP) or laparoscopic radical prostatectomy [ 3 ]. Although radical prostatectomy has been established as a safe and effective surgical procedure, any of several, postoperative complications may occur. Inguinal hernia (IH) is one such complication; it is common in elderly males and has a higher incidence in patients undergoing ORP. Regan et al. were the first to describe IH as a complication of ORP and reported an incidence of 12% at postoperative month 6 [ 4 ]. Later studies reported a post-ORP incidence of 10–24% [ 5 – 11 ]. Several other studies reporting the incidence of postoperative IH after RARP suggested that the IH incidence ranged from 2–22%, which is higher than the spontaneous incidence [ 12 – 20 ]. It has also been suggested that various factors, including low body mass index (BMI), old age, and history of IH, are associated with IH after RARP [ 12 , 16 ]. Other factors in the incidence of IH after RARP include smoking history, poor surgical experience, and sarcopenia [ 12 , 18 , 20 ]. All these studies were conducted at a single center and enrolled a relatively small number of cases. To the best of our knowledge, there is as of yet no multicentric study of this topic enrolling a large cohort. Various surgical procedures have been proposed as means of preventing IH after RARP, including separating the processus vaginalis from the perineum and/or the vas deferens [ 21 – 24 ], plugging hemostatic agents into the inguinal canal and suture closing the internal inguinal ring (IIR) [ 25 ], sufficiently incising the peritoneum around the IIR, separating the spermatic vessels, and dissecting and cutting the vas deferens [ 19 , 26 ]. However, none of these methods have been established or standardized for RARP. The present study retrospectively investigated the incidence and risk factors of post-RARP IH development using a multicentric database containing data on more than 3,000 Japanese patients with prostate cancer. The study also evaluated the efficacy of surgical procedures for IH prevention. Methods Patients The institutional review board of Tokyo Metropolitan Cancer and Infectious Diseases Center at Komagome Hospital (approval number: 2783) and the other participating institutions reviewed and approved this study. All procedures were conducted in accordance with the relevant local guidelines and regulations. The requirement for the patients’ informed consent was waived because of the retrospective design. Based on the provisions of the ethics committee and ethics guidelines of Japan, written consent was not required; the results of retrospective and observational studies using existing documentation have already been made public. The present study retrospectively reviewed a multicentric cohort (the MSUG94 group) of 3,195 patients with prostate cancer who underwent RARP at nine hopitals in Japan between September 2012 and August 202. The participating hospitals were Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, Hiroshima City Hiroshima Citizens Hospital, Yokohama City University, University of Toyama, Dokkyo Medical University Saitama Medical Center, Gifu University Graduate School of Medicine, Mie University Graduate School of Medicine, Seirei Hamamatsu General Hospital, and Toranomon Hospital. Preoperative patient characteristics included age, height, weight, serum prostate-specific antigen (PSA) level, biopsy grade group (GG), clinical T stage, National Comprehensive Cancer Network (NCCN) risk classification, Eastern Cooperative Oncology Group performance status, and history of neoadjuvant androgen deprivation therapy (ADT). The tumors were staged according to the 8th edition of the TNM staging system of the American Joint Committee on Cancer. High-volume hospital was defined as a hospital performing more than 100 RARPs annually. Surgical procedure and medical follow-up schedule All the patients received RARP using the da Vinci Robot Surgical System (Intuitive Surgical G.K., Japan). RARP was conducted via the transperitoneal anterior approach in most cases. Whether or not pelvic lymph node dissection (PLND), nerve-sparing procedures or IH prevention procedures were performed was decided at the surgeon’s discretion or the policy of the treating hospital. Since surgical procedures for IH prevention varied among the hospitals, the following procedures were used as exploratory variables: isolation of the vas deferens, transection of the vas deferens, isolation of the spermatic vessels, separation of the peritoneum from the IIR, and suture closure of the peritoneum. All the patients were followed at three-month intervals after surgery. IH was diagnosed on the basis of clinical symptoms and physical examination findings. Endpoints and statistical analysis The primary and secondary endpoints were IH-free survival and any association between IH development after RARP and clinical covariates. JMP 14 (SAS Institute Inc., Cary, NC, USA) was used for data analyses. Pearson’s chi-square and the Mann-Whitney U test were used to evaluate intergroup differences in categorical and continuous values, respectively. IH-free survival after RARP was estimated using the Kaplan-Meier method. Intergroup differences in IH-free survival were assessed using the log-rank test. Univariate and multivariate Cox proportional hazard regression models were used to assess for risk factors of IH development. Two-sided p < 0.05 was considered to indicate statistical significance. Results Table 1 summarizes the patient characteristics. Of the 3,195 patients enrolled, 34 (1.0%) were excluded owing to incomplete data. Six (0.2%) patients undergoing RARP via the retroperitoneal approach were also excluded, leaving 3,155 patients for analysis. The median follow-up period was 24 months. The median (interquartile range [IQR]) age, initial PSA level, and BMI was 69 (64–72) years, 7.9 (5.7–12) ng/mL, and 23.6 (21.8–25.6) kg/m 2 , respectively. According to the NCCN risk classification, 341 (10.8%), 1,584 (50.2%), 1,173 (37.2%), and 57 (1.8%) patients were classified as having a low, intermediate, high, and very high risk for prostate cancer, respectively. In total, 433 (13.7%) patients received neoadjuvant ADT. Two hospitals were classified as high-volume hospitals, and 1665 (52.8%) patients underwent RARP at these hospitals. The median console time was 162 minutes. Extended lymph node dissection (ePLND) and nerve-sparing procedures were performed in 396 (12.6%) and 874 (27.7%) patients, respectively. IH prevention was attempted at five of the nine hospitals, with 1,465 (46.4%) men receiving a procedure for IH prevention. In the latter, one or more of the procedures listed in Table 1 were performed solely or in combination. Table 1 Patient characteristics Variable N (%) Total 3155 Age, median, years † 69 (64–72) BMI, median, kg/m 2† 23.6 (21.8–25.6) Initial PSA, median, ng/ml † 7.9 (5.7–12) Biopsy GG 1 611 (19.4) 2 905 (28.7) 3 625 (19.8) 4 709 (22.5) 5 305 (9.7) Clinical T stage 1 575 (18.2) 2 2223 (70.5) 3 354 (11.2) 4 3 (0.1) NCCN risk classification Low 341 (10.8) Intermediate 1584 (50.2) High 1173 (37.2) Ver high 57 (1.8) D'Amico risk classification Low 359 (11.4) Intermediate 1266 (40.1) High 1530 (48.5) ECOG PS 0 3067 (97.2) 1 84 (2.7) 2 4 (0.1) Neoadjuvant therapy None 2722 (86.3) Performed 433 (13.7) PLND None 983 (31.2) Performed 2172 (68.8) ePLND None 2759 (87.4) Performed 396 (12.6) NS None 2281 (72.3) Performed 874 (27.7) Procedures for IH prevention Transecting the vas deferens None 1535 (48.7) Performed 1411 (44.7) Unknown 209 (6.6) Isolating the spermatic vessels None 1690 (53.6) Performed 1465 (46.4) Separating the peritoneum from IIR None 2086 (66.1) Performed 1069 (33.9) Closing the peritoneum None 3137 (99.4) Performed 18 (0.6) Hospital volume Low 1490 (47.2) High 1665 (52.8) Console time, minutes † 162 (121–211) † Variables are presented as the median (IQR). BMI, body mass index; ECOG PS, Eastern Cooperative Oncology Group Performance Status; ePLND, extended pelvic lymph node dissection; GG, grade group; IH, inguinal hernia; IIR, internal inguinal ring; IQR, interquartile range; NCCN, the National Comprehensive Cancer Network; NS, nerve sparing; PLND, pelvic lymph node dissection; PSA, prostate-specific antigen; RARP, Robot-assisted radical prostatectomy. The Mann–Whitney U test and Pearson’s chi-square test were used to compare continuous and categorical variables, respectively. IH developed in 243 patients. The IH-free survival rate at year 1, 2, and 3 after RARP was 94.3%, 91.7%, and 90.5%, respectively (Fig. 1 A). Table 2 shows results of univariate and multivariate analyses for risk factors of IH development. On univariate analysis, old age ( p = 0.001), low BMI ( p < 0.001), low hospital volume ( p = 0.007), transecting the vas deferens ( p = 0.001), isolating the spermatic vessels ( p = 0.005), and separating the peritoneum from the IIR ( p = 0.015) were significantly associated with IH development. Multivariate analysis revealed that old age (HR: 1.037; 95% CI: 1.014–1.061; p = 0.001), low BMI (HR: 0.904; 95% CI: 0.863–0.946; p < 0.001), and low hospital volume (HR: 1.385; 95% CI: 1.003–1.902; p = 0.048) were independently associated with IH development. None of the procedures for IH prevention were associated with IH development. When the patients were dichotomized by the median age and BMI, the two-year IH-free survival rate was 93.9% and 89.4% in patients aged ≤ 68 years and patients aged ≥ 69 years, respectively ( p 23.6 and ≤ 23.6, respectively ( p < 0.001; Fig. 1 C). In terms of hospital volume, the two-year IH-free survival rate was 92.4% and 90.8% at high volume hospitals and other hospitals, respectively ( p = 0.007; Fig. 1 D). Table 2 Cox regression analysis of risk factors of IH Variable Univariate Multivariate HR (95% CI) P value HR (95% CI) P value Age (continuous) 1.037 (1.014–1.060) 0.001 1.037 (1.014–1.061) 0.001 BMI (continuous) 0.894 (0.854–0.935) < 0.001 0.904 (0.863–0.946) < 0.001 Initial PSA (continuous) 0.999 (0.987–1.008) 0.905 1.002 (0.989–1.011) 0.756 Biopsy GG ≥ 3 (vs. ≤2) 0.881 (0.684–1.133) 0.324 0.900 (0.690–1.173) 0.438 Clinical T stage ≥ 3 (vs. ≤2) 1.019 (0.673–1.483) 0.926 1.191 (0.761–1.798) 0.431 Neoadjuvant therapy (vs. none) 0.701 (0.434–1.070) 0.103 0.642 (0.382–1.025) 0.064 Console time (continuous) 1.001 (0.999–1.003) 0.152 0.999 (0.998–1.002) 0.937 Low hospital volume (vs. high) 1.426 (1.102–1.846) 0.007 1.385 (1.003–1.902) 0.048 Transecting the vas deferens (performed vs. none) 1.551 (1.187–2.029) 0.001 1.238 (0.693–2.154) 0.462 Transecting the vas deferens (unknown vs. none) 1.569 (0.954–2.456) 0.074 1.268 (0.732–2.121) 0.387 Transecting the vas deferens (unknown vs. performed) 1.011 (0.617–1.576) 0.962 1.024 (0.504–2.107) 0.947 Isolating the spermatic vessels (vs. none) 1.443 (1.118–1.863) 0.005 1.201 (0.696–2.065) 0.508 Separating the peritoneum from IIR (vs. none) 1.390 (1.067-1.800) 0.015 1.062 (0.627–1.872) 0.829 BMI, body mass index; CI, confidence interval; GG, grade group; HR, hazard ratio; IIR, internal inguinal ring; PSA, prostate-specific antigen. Discussion Although IH is a common complication of RARP, most previous studies enrolled a monocentric cohort comprising a relatively small number of patients (800 at most) [ 12 – 20 ]. Since the surgical factors associated with RARP procedures can influence the risk of IH development, a multicentric study enrolling a large number of patients may be more ideal for assessing the real-world incidence of IH development. Previous studies reported that the incidence of post-RARP IH ranged from 2–22% [ 12 – 20 ]. The present, multicentric study enrolling more than 3,000 Japanese patients demonstrated that the cumulative incidence of post-RARP IH was 8.3% at postoperative year 2 and 9.5% at postoperative year 3, which is within the incidence range for post-RARP IH reported previously and may represent its current, real-world incidence in Japan. In the general population, the risk factors of IH include male sex, old age, patent processus vaginalis, low BMI, smoking, sports activity, and surgery involving lower abdominal incisions [ 12 , 15 , 20 ]. Thus, IH development appears attributable, at least partly, to a frail body and vulnerability of the abdominal wall. In the post-RARP setting, previous studies reported old age [ 16 ] and low BMI [ 12 ] as risk factors of IH. The present study collaborates these findings using a multicentric large cohort. Some studies reported that surgeons with limited experience were a risk factor of post-RARP IH [ 12 , 20 ]. In the present study, the association of the latter with IH was unable to be assessed because the surgeons’ experience was unavailable in the database. However, our study demonstrated a higher incidence of IH in low volume hospitals than high volume hospitals. This finding can be made only on the basis of multicentric studies and suggests the importance of surgeons’ experience with RARP as a factor in post-RARP IH development. The present study provided some insights into the real-world practice related to IH prevention in Japan. Some procedure for IH prevention was performed in up to half the cohort at about half the hospitals. Thus far, several surgical procedures have been proposed for post-RARP IH prevention. Some researchers have proposed separating the processus vaginalis from the perineum and/or vas deferens [ 21 – 24 ]. Lee et al. reported a simple method in cases of patent processus vaginalis (PPV) which consists of transecting the PPV, plugging a hemostatic agent into the detached canal end, and suture closing the internal inguinal floor [ 25 ]. Their study found IH in 16 (34%) of 47 groins of patients who did not receive IH prevention while none of those who received IH prevention had IH during the 12-month follow-up period. Shimbo et al. reported a technique involving dissecting the vas deferens from the peritoneum, incising the peritoneum around the IIR, and separating the spermatic vessels [ 19 , 26 ]. They demonstrated that the IH incidence was 20.8% in the non-prevention group and 8.5% in the prevention group during a median follow-up of 99.5 months and 89.9 months, respectively. These studies have emphasized two important technical points in reducing traction on the IIR to prevent IH: complete punchout of the peritoneum around the IIR to separate its connection with the processus vaginalis and transecting the vas deferens to reduce traction on the IIR resulting from vesicourethral anastomosis [ 26 ]. Peritoneal closure in cases of a transabdominal approach has also been reported as a method of preventing IH [ 27 , 28 ]. Currently, despite the various methods proposed, surgical procedures for IH prevention have not yet been established or standardized. In fact, whether and how IH prevention was performed has depended on institutional protocols; thus, in the present study the methods varied across hospitals and were heterogeneous throughout the cohort. Therefore, IH prevention procedures were factorized into four categories: transecting the vas deferens, separating the spermatic vessels, separating the peritoneum and IIR, and closing the peritoneum. In the present study, none of the first three procedures were associated with a reduction in IH incidence. Peritoneal closure was not included in the multivariable analysis because of the small number of cases (n = 18) in which this procedure was utilized. Fujii et al. reported a preventive effect of peritoneal closure against IH after RARP [ 27 , 28 ]. Our results would not negate the preventive efficacy of each of the factorized procedures. Further, it may be important to perform these procedures in combination while keeping in mind the uniform concepts advocated by Shimbo et al [ 26 ]. Prospective, multicentric studies are needed to verify the efficacy of IH prevention techniques and to standardize the procedures. This study has several limitations. First, because of its retrospective nature, some biases might have been introduced during data collection and analysis. Indications for IH prevention depended on institutional protocols, which could have led to a selection bias. Second, because IH prevention techniques had not been standardized in this study, we could not assess their efficacy as a set of procedures. Therefore, their association after factorization with post-RARP IH development was assessed. Third, Retzius-sparing RARP, which is reportedly effective in preventing IH [ 13 ], was excluded from the analysis because of the small number of cases (n = 6). In the present cohort, none of the patients receiving Retzius-sparing RARP or closure of the peritoneum had IH development. These procedures should be included and assessed in future studies. Last, the follow-up period may have been too short to assess the incidence of post-RARP IH or to identify the risk factors precisely. Despite these potential limiations, our findings demonstrate the incidence and risk factors of post-RARP IH in real-world clinical practice in Japan. In conclusion, the present study, using a multicentric database of more than 3,000 RARP cases, demonstrated the incidence of IH and found that old age, low BMI, and low hospital volume were its chief risk factors. These findings may represent the current, real-world status of post-RARP IH in Japan. The efficacy of surgical procedures for IH prevention should be further investigated in well-designed, prospective studies to establish and standardize the surgical techniques. Declarations Fundings: This study did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector. Co mpeting Interest: The authors of this paper have no financial or nonfinancial interests that are directly or indirectly related to the work submitted for publication. Acknowledgments: None. Author Contributions: Masahiro Toide: Project development, Data collection, Data analysis, and Manuscript writing Shin Ebara: Project development, Data collection, and Manuscript writing Tomoyuki Tatenuma: Data collection and Manuscript writing Yoshinori Ikehata: Data collection and Manuscript writing Akinori Nakayama: Data collection and Manuscript writing Daiki Kato: Data collection and Manuscript writing Takeshi Sasaki: Data collection and Manuscript writing Tatsuaki Yoneda: Project development, Data collection, and Manuscript writing Kazushige Sakaguchi: Data collection and Manuscript writing Jun Teishima: Project development, Data collection, and Manuscript writing Kazuhide Makiyama: Project development, Data collection, and Manuscript writing Hiroshi Kitamura: Project development, Data collection, and Manuscript writing Kazutaka Saito: Project development, Data collection, and Manuscript writing Takuya Koie: Project development, Data collection, and Manuscript writing Takahiro Inoue: Project development, Data collection, and Manuscript writing Shinji Urakami: Project development, Data collection, and Manuscript writing Fumitaka Koga: Project development, Data collection, Data analysis, and Manuscript writing Ethical approval: Received from the Japanese Ethics Committee and Ethics Guidelines. Institutional review board approval was obtained (#2783). Informed Consent Statement: For this type of study, formal consent is not required. Pursuant to the provisions of the ethics committee and the ethic guideline in Japan, written consent was not required in exchange for public disclosure of study information in the case of retrospective and/or observational study using a material such as the existing documentation. Consent to participate: Retrospective study, no consent required. Consent to publication: Taken from the Institute. Data Availability Statement: The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy and ethical reasons. References Daniyal M, Siddiqui ZA, Akram M, Asif HM, Sultana S, Khan A (2014) Epidemiology, etiology, diagnosis and treatment of prostate cancer. 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J Urol 191:468-472. https://doi.org/10.1016/j.juro.2013.09.035 Shimbo M, Endo F, Matsubara T, Shimada G, Hattori K (2022) Long-term results after robot-assisted radical prostatectomy of a simplified inguinal hernia prevention technique without artificial substance use. Int J Urol 29:1315-1321. https://doi.org/10.1111/iju.14989 Fujii Y (2020) [Prevention of inguinal hernia after radical prostatectomy; overview] Zenritsusen zentekijojyutsu go no sokei hernia no yobou overview (in Japanese). Nihon Minimamu Sou Hinyouki Naishikyou Geka Gakkai zasshi 12:19-24 Soma T, Fukuda S, Matsuyama Y et al. (2023) Peritoneal closure and the processus vaginalis transection method to prevent inguinal hernia after robot-assisted radical prostatectomy. Int J Urol. https://doi.org/10.1111/iju.15170 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 17 Jan, 2024 Read the published version in Journal of Robotic Surgery → Version 1 posted Editorial decision: Major revision 01 Sep, 2023 Reviews received at journal 28 Aug, 2023 Reviewers agreed at journal 23 Aug, 2023 Reviewers invited by journal 19 Aug, 2023 Editor assigned by journal 16 Jul, 2023 Submission checks completed at journal 10 Jul, 2023 First submitted to journal 09 Jul, 2023 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About In Review Editorial Policies Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3153830","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":217316171,"identity":"83483176-6453-426b-8e37-c2fb580f788b","order_by":0,"name":"Masahiro Toide","email":"","orcid":"","institution":"Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Masahiro","middleName":"","lastName":"Toide","suffix":""},{"id":217316175,"identity":"293cc584-4ef8-4cba-a6f6-578c50c83007","order_by":1,"name":"Shin Ebara","email":"","orcid":"","institution":"Hiroshima City Hiroshima Citizens Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Shin","middleName":"","lastName":"Ebara","suffix":""},{"id":217316178,"identity":"54ead096-d870-4b8e-87c6-767a19885655","order_by":2,"name":"Tomoyuki Tatenuma","email":"","orcid":"","institution":"Yokohama City University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Tomoyuki","middleName":"","lastName":"Tatenuma","suffix":""},{"id":217316180,"identity":"ddaea9d3-58e6-4f23-b7b0-2030ff5cc7d8","order_by":3,"name":"Yoshinori Ikehata","email":"","orcid":"","institution":"University of Toyama","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Yoshinori","middleName":"","lastName":"Ikehata","suffix":""},{"id":217316184,"identity":"df52c7b4-1023-4e37-94fb-21e7542691ad","order_by":4,"name":"Akinori Nakayama","email":"","orcid":"","institution":"Dokkyo Medical University Saitama Medical 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University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Kazuhide","middleName":"","lastName":"Makiyama","suffix":""},{"id":217316202,"identity":"ccc453e2-aa6d-458e-8aa1-bef9482dddd3","order_by":11,"name":"Hiroshi Kitamura","email":"","orcid":"","institution":"University of Toyama","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Hiroshi","middleName":"","lastName":"Kitamura","suffix":""},{"id":217316204,"identity":"c3843908-1e79-4cc8-8135-bbc25881e1a9","order_by":12,"name":"Kazutaka Saito","email":"","orcid":"","institution":"Dokkyo Medical University Saitama Medical Center","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Kazutaka","middleName":"","lastName":"Saito","suffix":""},{"id":217316206,"identity":"04e0b888-e412-4cb0-a9b0-d7fc399ab95a","order_by":13,"name":"Takuya Koie","email":"","orcid":"","institution":"Gifu University Graduate School of Medicine","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Takuya","middleName":"","lastName":"Koie","suffix":""},{"id":217316208,"identity":"fd79b2ed-351c-4467-b185-12dae2e72a53","order_by":14,"name":"Takahiro Inoue","email":"","orcid":"","institution":"Mie University Graduate School of Medicine","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Takahiro","middleName":"","lastName":"Inoue","suffix":""},{"id":217316210,"identity":"d45c7281-26b7-4438-8795-5e8fd8991dd5","order_by":15,"name":"Shinji Urakami","email":"","orcid":"","institution":"Toranomon Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Shinji","middleName":"","lastName":"Urakami","suffix":""},{"id":217316212,"identity":"080d7d61-a862-4d5c-87a7-d137aea44ecc","order_by":16,"name":"Fumitaka Koga","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA80lEQVRIiWNgGAWjYBAC9gYGhgMMDAkMDDwgbgUDgwEDBOMEPED1Bw7AtZwxIE4LA1wLY5sBfuVgLRLZiYc/1KTJM/AcPvzi57w/0ebSDQzFBXi15G44cOBYjmEDb1uaZe82g9ydcw4wGM/Ao8UerIWtgrGBn8fMgBeoZcONBAZjHoK2/KuwB2kx/DuHWC0H23ISG3h7jB/zNhCjhefthgNn+9KSG3iOpTHLHDPO3XDnYANev/Cw527+UPEt2baBJ/nwxzc1crkbbjcfM8YXYnBgf4CBTQLMkmBsMyZGBwgwf4BoYWB+TKyWUTAKRsEoGBEAAMtzVccg3LM1AAAAAElFTkSuQmCC","orcid":"","institution":"Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Fumitaka","middleName":"","lastName":"Koga","suffix":""}],"badges":[],"createdAt":"2023-07-09 13:14:22","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3153830/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3153830/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s11701-023-01761-1","type":"published","date":"2024-01-17T15:01:47+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":40038640,"identity":"005d7c00-4f3e-419a-9148-95f79b270438","added_by":"auto","created_at":"2023-07-14 14:49:18","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":157754,"visible":true,"origin":"","legend":"\u003cp\u003eKaplan-Meier curve of the IH-free survival rate in 3,155 patients undergoing robot-assisted radical prostatectomy (RARP) in a multicentric cohort (A); Kaplan–Meier curves of the IH-free survival rate after stratification by age (cutoff: 69 years) (B), body mass index (BMI) stratified by a cutoff of 23.6 kg/m2 (C), and hospital volume (D)\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-3153830/v1/8c6c44d8b95ec4861b1ba632.jpeg"},{"id":49978911,"identity":"54c9b39e-4922-49a3-929d-c79ad1152dd3","added_by":"auto","created_at":"2024-01-22 15:10:04","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":429192,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3153830/v1/3c6875f5-8081-4931-8e5f-f5bb25939600.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Incidence and risk factors of inguinal hernia after robot-assisted radical prostatectomy: a retrospective multicenter cohort study in Japan (the MSUG94 group)","fulltext":[{"header":"Introduction","content":"\u003cp\u003eProstate cancer is one of the most common types of cancer in men worldwide, and the radical prostatectomy is the standard of care for localized prostate cancer [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Surgical approaches have changed from open to laparoscopic surgery and then to robot-assisted laparoscopic surgery. The robot-assisted radical prostatectomy (RARP) is now widely used and more commonly performed in the United States than the open retropubic radical prostatectomy (ORP) or laparoscopic radical prostatectomy [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Although radical prostatectomy has been established as a safe and effective surgical procedure, any of several, postoperative complications may occur. Inguinal hernia (IH) is one such complication; it is common in elderly males and has a higher incidence in patients undergoing ORP. Regan et al. were the first to describe IH as a complication of ORP and reported an incidence of 12% at postoperative month 6 [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Later studies reported a post-ORP incidence of 10\u0026ndash;24% [\u003cspan additionalcitationids=\"CR6 CR7 CR8 CR9 CR10\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Several other studies reporting the incidence of postoperative IH after RARP suggested that the IH incidence ranged from 2\u0026ndash;22%, which is higher than the spontaneous incidence [\u003cspan additionalcitationids=\"CR13 CR14 CR15 CR16 CR17 CR18 CR19\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. It has also been suggested that various factors, including low body mass index (BMI), old age, and history of IH, are associated with IH after RARP [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Other factors in the incidence of IH after RARP include smoking history, poor surgical experience, and sarcopenia [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. All these studies were conducted at a single center and enrolled a relatively small number of cases. To the best of our knowledge, there is as of yet no multicentric study of this topic enrolling a large cohort.\u003c/p\u003e \u003cp\u003eVarious surgical procedures have been proposed as means of preventing IH after RARP, including separating the processus vaginalis from the perineum and/or the vas deferens [\u003cspan additionalcitationids=\"CR22 CR23\" citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e], plugging hemostatic agents into the inguinal canal and suture closing the internal inguinal ring (IIR) [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], sufficiently incising the peritoneum around the IIR, separating the spermatic vessels, and dissecting and cutting the vas deferens [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. However, none of these methods have been established or standardized for RARP.\u003c/p\u003e \u003cp\u003eThe present study retrospectively investigated the incidence and risk factors of post-RARP IH development using a multicentric database containing data on more than 3,000 Japanese patients with prostate cancer. The study also evaluated the efficacy of surgical procedures for IH prevention.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePatients\u003c/h2\u003e \u003cp\u003e The institutional review board of Tokyo Metropolitan Cancer and Infectious Diseases Center at Komagome Hospital (approval number: 2783) and the other participating institutions reviewed and approved this study. All procedures were conducted in accordance with the relevant local guidelines and regulations. The requirement for the patients\u0026rsquo; informed consent was waived because of the retrospective design. Based on the provisions of the ethics committee and ethics guidelines of Japan, written consent was not required; the results of retrospective and observational studies using existing documentation have already been made public.\u003c/p\u003e \u003cp\u003e The present study retrospectively reviewed a multicentric cohort (the MSUG94 group) of 3,195 patients with prostate cancer who underwent RARP at nine hopitals in Japan between September 2012 and August 202. The participating hospitals were Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, Hiroshima City Hiroshima Citizens Hospital, Yokohama City University, University of Toyama, Dokkyo Medical University Saitama Medical Center, Gifu University Graduate School of Medicine, Mie University Graduate School of Medicine, Seirei Hamamatsu General Hospital, and Toranomon Hospital. Preoperative patient characteristics included age, height, weight, serum prostate-specific antigen (PSA) level, biopsy grade group (GG), clinical T stage, National Comprehensive Cancer Network (NCCN) risk classification, Eastern Cooperative Oncology Group performance status, and history of neoadjuvant androgen deprivation therapy (ADT). The tumors were staged according to the 8th edition of the TNM staging system of the American Joint Committee on Cancer. High-volume hospital was defined as a hospital performing more than 100 RARPs annually.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eSurgical procedure and medical follow-up schedule\u003c/h2\u003e \u003cp\u003eAll the patients received RARP using the da Vinci Robot Surgical System (Intuitive Surgical G.K., Japan). RARP was conducted via the transperitoneal anterior approach in most cases. Whether or not pelvic lymph node dissection (PLND), nerve-sparing procedures or IH prevention procedures were performed was decided at the surgeon\u0026rsquo;s discretion or the policy of the treating hospital. Since surgical procedures for IH prevention varied among the hospitals, the following procedures were used as exploratory variables: isolation of the vas deferens, transection of the vas deferens, isolation of the spermatic vessels, separation of the peritoneum from the IIR, and suture closure of the peritoneum. All the patients were followed at three-month intervals after surgery. IH was diagnosed on the basis of clinical symptoms and physical examination findings.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eEndpoints and statistical analysis\u003c/h2\u003e \u003cp\u003eThe primary and secondary endpoints were IH-free survival and any association between IH development after RARP and clinical covariates. JMP 14 (SAS Institute Inc., Cary, NC, USA) was used for data analyses. Pearson\u0026rsquo;s chi-square and the Mann-Whitney U test were used to evaluate intergroup differences in categorical and continuous values, respectively. IH-free survival after RARP was estimated using the Kaplan-Meier method. Intergroup differences in IH-free survival were assessed using the log-rank test. Univariate and multivariate Cox proportional hazard regression models were used to assess for risk factors of IH development. Two-sided \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered to indicate statistical significance.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e summarizes the patient characteristics. Of the 3,195 patients enrolled, 34 (1.0%) were excluded owing to incomplete data. Six (0.2%) patients undergoing RARP via the retroperitoneal approach were also excluded, leaving 3,155 patients for analysis. The median follow-up period was 24 months. The median (interquartile range [IQR]) age, initial PSA level, and BMI was 69 (64\u0026ndash;72) years, 7.9 (5.7\u0026ndash;12) ng/mL, and 23.6 (21.8\u0026ndash;25.6) kg/m\u003csup\u003e2\u003c/sup\u003e, respectively. According to the NCCN risk classification, 341 (10.8%), 1,584 (50.2%), 1,173 (37.2%), and 57 (1.8%) patients were classified as having a low, intermediate, high, and very high risk for prostate cancer, respectively. In total, 433 (13.7%) patients received neoadjuvant ADT. Two hospitals were classified as high-volume hospitals, and 1665 (52.8%) patients underwent RARP at these hospitals. The median console time was 162 minutes. Extended lymph node dissection (ePLND) and nerve-sparing procedures were performed in 396 (12.6%) and 874 (27.7%) patients, respectively. IH prevention was attempted at five of the nine hospitals, with 1,465 (46.4%) men receiving a procedure for IH prevention. In the latter, one or more of the procedures listed in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e were performed solely or in combination.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePatient characteristics\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eN (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3155\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge, median, years\u003csup\u003e\u0026dagger;\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e69 (64\u0026ndash;72)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI, median, kg/m\u003csup\u003e2\u0026dagger;\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e23.6 (21.8\u0026ndash;25.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInitial PSA, median, ng/ml\u003csup\u003e\u0026dagger;\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.9 (5.7\u0026ndash;12)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBiopsy GG\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e611 (19.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e905 (28.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e625 (19.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e709 (22.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e305 (9.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eClinical T stage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e575 (18.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2223 (70.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e354 (11.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 (0.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNCCN risk classification\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e341 (10.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIntermediate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1584 (50.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1173 (37.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eVer high\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e57 (1.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eD'Amico risk classification\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e359 (11.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIntermediate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1266 (40.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1530 (48.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eECOG PS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3067 (97.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e84 (2.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (0.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNeoadjuvant therapy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2722 (86.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePerformed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e433 (13.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePLND\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e983 (31.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePerformed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2172 (68.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eePLND\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2759 (87.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePerformed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e396 (12.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2281 (72.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePerformed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e874 (27.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProcedures for IH prevention\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTransecting the vas deferens\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1535 (48.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePerformed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1411 (44.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUnknown\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e209 (6.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIsolating the spermatic vessels\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1690 (53.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePerformed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1465 (46.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSeparating the peritoneum from IIR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2086 (66.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePerformed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1069 (33.9)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eClosing the peritoneum\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3137 (99.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePerformed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18 (0.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHospital volume\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1490 (47.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1665 (52.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eConsole time, minutes\u003csup\u003e\u0026dagger;\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e162 (121\u0026ndash;211)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"3\"\u003e\u0026dagger; Variables are presented as the median (IQR).\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"3\"\u003eBMI, body mass index; ECOG PS, Eastern Cooperative Oncology Group Performance Status; ePLND, extended pelvic lymph node dissection; GG, grade group; IH, inguinal hernia; IIR, internal inguinal ring; IQR, interquartile range; NCCN, the National Comprehensive Cancer Network; NS, nerve sparing; PLND, pelvic lymph node dissection; PSA, prostate-specific antigen; RARP, Robot-assisted radical prostatectomy.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"3\"\u003eThe Mann\u0026ndash;Whitney U test and Pearson\u0026rsquo;s chi-square test were used to compare continuous and categorical variables, respectively.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eIH developed in 243 patients. The IH-free survival rate at year 1, 2, and 3 after RARP was 94.3%, 91.7%, and 90.5%, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA).\u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows results of univariate and multivariate analyses for risk factors of IH development. On univariate analysis, old age (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001), low BMI (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), low hospital volume (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.007), transecting the vas deferens (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001), isolating the spermatic vessels (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.005), and separating the peritoneum from the IIR (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.015) were significantly associated with IH development. Multivariate analysis revealed that old age (HR: 1.037; 95% CI: 1.014\u0026ndash;1.061; \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001), low BMI (HR: 0.904; 95% CI: 0.863\u0026ndash;0.946; \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and low hospital volume (HR: 1.385; 95% CI: 1.003\u0026ndash;1.902; \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.048) were independently associated with IH development. None of the procedures for IH prevention were associated with IH development. When the patients were dichotomized by the median age and BMI, the two-year IH-free survival rate was 93.9% and 89.4% in patients aged\u0026thinsp;\u0026le;\u0026thinsp;68 years and patients aged\u0026thinsp;\u0026ge;\u0026thinsp;69 years, respectively (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001; Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB); and 94.5% and 88.9% in patients with BMI\u0026thinsp;\u0026gt;\u0026thinsp;23.6 and \u0026le;\u0026thinsp;23.6, respectively (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001; Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eC). In terms of hospital volume, the two-year IH-free survival rate was 92.4% and 90.8% at high volume hospitals and other hospitals, respectively (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.007; Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eD).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCox regression analysis of risk factors of IH\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eUnivariate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eMultivariate\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHR (95% CI)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eP value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHR (95% CI)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (continuous)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.037 (1.014\u0026ndash;1.060)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.037 (1.014\u0026ndash;1.061)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI (continuous)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.894 (0.854\u0026ndash;0.935)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.904 (0.863\u0026ndash;0.946)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInitial PSA (continuous)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.999 (0.987\u0026ndash;1.008)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.905\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.002 (0.989\u0026ndash;1.011)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.756\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBiopsy GG\u0026thinsp;\u0026ge;\u0026thinsp;3 (vs. \u0026le;2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.881 (0.684\u0026ndash;1.133)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.324\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.900 (0.690\u0026ndash;1.173)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.438\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eClinical T stage\u0026thinsp;\u0026ge;\u0026thinsp;3 (vs. \u0026le;2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.019 (0.673\u0026ndash;1.483)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.926\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.191 (0.761\u0026ndash;1.798)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.431\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNeoadjuvant therapy (vs. none)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.701 (0.434\u0026ndash;1.070)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.103\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.642 (0.382\u0026ndash;1.025)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.064\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eConsole time (continuous)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.001 (0.999\u0026ndash;1.003)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.152\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.999 (0.998\u0026ndash;1.002)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.937\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLow hospital volume (vs. high)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.426 (1.102\u0026ndash;1.846)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.385 (1.003\u0026ndash;1.902)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.048\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTransecting the vas deferens (performed vs. none)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.551 (1.187\u0026ndash;2.029)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.238 (0.693\u0026ndash;2.154)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.462\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTransecting the vas deferens (unknown vs. none)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.569 (0.954\u0026ndash;2.456)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.074\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.268 (0.732\u0026ndash;2.121)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.387\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTransecting the vas deferens (unknown vs. performed)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.011 (0.617\u0026ndash;1.576)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.962\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.024 (0.504\u0026ndash;2.107)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.947\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIsolating the spermatic vessels (vs. none)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.443 (1.118\u0026ndash;1.863)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.005\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.201 (0.696\u0026ndash;2.065)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.508\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSeparating the peritoneum from IIR (vs. none)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.390 (1.067-1.800)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.015\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.062 (0.627\u0026ndash;1.872)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.829\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eBMI, body mass index; CI, confidence interval; GG, grade group; HR, hazard ratio; IIR, internal inguinal ring; PSA, prostate-specific antigen.\u003c/td\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eAlthough IH is a common complication of RARP, most previous studies enrolled a monocentric cohort comprising a relatively small number of patients (800 at most) [\u003cspan additionalcitationids=\"CR13 CR14 CR15 CR16 CR17 CR18 CR19\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Since the surgical factors associated with RARP procedures can influence the risk of IH development, a multicentric study enrolling a large number of patients may be more ideal for assessing the real-world incidence of IH development. Previous studies reported that the incidence of post-RARP IH ranged from 2\u0026ndash;22% [\u003cspan additionalcitationids=\"CR13 CR14 CR15 CR16 CR17 CR18 CR19\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. The present, multicentric study enrolling more than 3,000 Japanese patients demonstrated that the cumulative incidence of post-RARP IH was 8.3% at postoperative year 2 and 9.5% at postoperative year 3, which is within the incidence range for post-RARP IH reported previously and may represent its current, real-world incidence in Japan.\u003c/p\u003e \u003cp\u003eIn the general population, the risk factors of IH include male sex, old age, patent processus vaginalis, low BMI, smoking, sports activity, and surgery involving lower abdominal incisions [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Thus, IH development appears attributable, at least partly, to a frail body and vulnerability of the abdominal wall. In the post-RARP setting, previous studies reported old age [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] and low BMI [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] as risk factors of IH. The present study collaborates these findings using a multicentric large cohort. Some studies reported that surgeons with limited experience were a risk factor of post-RARP IH [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. In the present study, the association of the latter with IH was unable to be assessed because the surgeons\u0026rsquo; experience was unavailable in the database. However, our study demonstrated a higher incidence of IH in low volume hospitals than high volume hospitals. This finding can be made only on the basis of multicentric studies and suggests the importance of surgeons\u0026rsquo; experience with RARP as a factor in post-RARP IH development.\u003c/p\u003e \u003cp\u003eThe present study provided some insights into the real-world practice related to IH prevention in Japan. Some procedure for IH prevention was performed in up to half the cohort at about half the hospitals. Thus far, several surgical procedures have been proposed for post-RARP IH prevention. Some researchers have proposed separating the processus vaginalis from the perineum and/or vas deferens [\u003cspan additionalcitationids=\"CR22 CR23\" citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Lee et al. reported a simple method in cases of patent processus vaginalis (PPV) which consists of transecting the PPV, plugging a hemostatic agent into the detached canal end, and suture closing the internal inguinal floor [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Their study found IH in 16 (34%) of 47 groins of patients who did not receive IH prevention while none of those who received IH prevention had IH during the 12-month follow-up period. Shimbo et al. reported a technique involving dissecting the vas deferens from the peritoneum, incising the peritoneum around the IIR, and separating the spermatic vessels [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. They demonstrated that the IH incidence was 20.8% in the non-prevention group and 8.5% in the prevention group during a median follow-up of 99.5 months and 89.9 months, respectively. These studies have emphasized two important technical points in reducing traction on the IIR to prevent IH: complete punchout of the peritoneum around the IIR to separate its connection with the processus vaginalis and transecting the vas deferens to reduce traction on the IIR resulting from vesicourethral anastomosis [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Peritoneal closure in cases of a transabdominal approach has also been reported as a method of preventing IH [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Currently, despite the various methods proposed, surgical procedures for IH prevention have not yet been established or standardized. In fact, whether and how IH prevention was performed has depended on institutional protocols; thus, in the present study the methods varied across hospitals and were heterogeneous throughout the cohort. Therefore, IH prevention procedures were factorized into four categories: transecting the vas deferens, separating the spermatic vessels, separating the peritoneum and IIR, and closing the peritoneum. In the present study, none of the first three procedures were associated with a reduction in IH incidence. Peritoneal closure was not included in the multivariable analysis because of the small number of cases (n\u0026thinsp;=\u0026thinsp;18) in which this procedure was utilized. Fujii et al. reported a preventive effect of peritoneal closure against IH after RARP [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Our results would not negate the preventive efficacy of each of the factorized procedures. Further, it may be important to perform these procedures in combination while keeping in mind the uniform concepts advocated by Shimbo et al [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Prospective, multicentric studies are needed to verify the efficacy of IH prevention techniques and to standardize the procedures.\u003c/p\u003e \u003cp\u003eThis study has several limitations. First, because of its retrospective nature, some biases might have been introduced during data collection and analysis. Indications for IH prevention depended on institutional protocols, which could have led to a selection bias. Second, because IH prevention techniques had not been standardized in this study, we could not assess their efficacy as a set of procedures. Therefore, their association after factorization with post-RARP IH development was assessed. Third, Retzius-sparing RARP, which is reportedly effective in preventing IH [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], was excluded from the analysis because of the small number of cases (n\u0026thinsp;=\u0026thinsp;6). In the present cohort, none of the patients receiving Retzius-sparing RARP or closure of the peritoneum had IH development. These procedures should be included and assessed in future studies. Last, the follow-up period may have been too short to assess the incidence of post-RARP IH or to identify the risk factors precisely. Despite these potential limiations, our findings demonstrate the incidence and risk factors of post-RARP IH in real-world clinical practice in Japan.\u003c/p\u003e \u003cp\u003eIn conclusion, the present study, using a multicentric database of more than 3,000 RARP cases, demonstrated the incidence of IH and found that old age, low BMI, and low hospital volume were its chief risk factors. These findings may represent the current, real-world status of post-RARP IH in Japan. The efficacy of surgical procedures for IH prevention should be further investigated in well-designed, prospective studies to establish and standardize the surgical techniques.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFundings:\u0026nbsp;\u003c/strong\u003eThis study did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCo\u003c/strong\u003e\u003cstrong\u003empeting\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;Interest:\u003c/strong\u003e The authors of this paper have no financial or nonfinancial interests that are directly or indirectly related to the work submitted for publication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments:\u0026nbsp;\u003c/strong\u003eNone.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMasahiro Toide: Project development, Data collection, Data analysis, and Manuscript writing\u003c/p\u003e\n\u003cp\u003eShin Ebara: Project development, Data collection, and Manuscript writing\u003c/p\u003e\n\u003cp\u003eTomoyuki Tatenuma: Data collection and Manuscript writing\u003c/p\u003e\n\u003cp\u003eYoshinori Ikehata: Data collection and Manuscript writing\u003c/p\u003e\n\u003cp\u003eAkinori Nakayama: Data collection and Manuscript writing\u003c/p\u003e\n\u003cp\u003eDaiki Kato: Data collection and Manuscript writing\u003c/p\u003e\n\u003cp\u003eTakeshi Sasaki: Data collection and Manuscript writing\u003c/p\u003e\n\u003cp\u003eTatsuaki Yoneda: Project development, Data collection, and Manuscript writing\u003c/p\u003e\n\u003cp\u003eKazushige Sakaguchi: Data collection and Manuscript writing\u003c/p\u003e\n\u003cp\u003eJun Teishima: Project development, Data collection, and Manuscript writing\u003c/p\u003e\n\u003cp\u003eKazuhide Makiyama: Project development, Data collection, and Manuscript writing\u003c/p\u003e\n\u003cp\u003eHiroshi Kitamura: Project development, Data collection, and Manuscript writing\u003c/p\u003e\n\u003cp\u003eKazutaka Saito: Project development, Data collection, and Manuscript writing\u003c/p\u003e\n\u003cp\u003eTakuya Koie: Project development, Data collection, and Manuscript writing\u003c/p\u003e\n\u003cp\u003eTakahiro Inoue: Project development, Data collection, and Manuscript writing\u003c/p\u003e\n\u003cp\u003eShinji Urakami: Project development, Data collection, and Manuscript writing\u003c/p\u003e\n\u003cp\u003eFumitaka Koga: Project development, Data collection, Data analysis, and Manuscript writing\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical approval:\u003c/strong\u003e Received from the Japanese Ethics Committee and Ethics Guidelines. Institutional review board approval was obtained (#2783).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInformed Consent Statement:\u0026nbsp;\u003c/strong\u003eFor this type of study, formal consent is not required. Pursuant to the provisions of the ethics committee and the ethic guideline in Japan, written consent was not required in exchange for public disclosure of study information in the case of retrospective and/or observational study using a material such as the existing documentation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to participate:\u0026nbsp;\u003c/strong\u003eRetrospective study, no consent required.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to publication:\u0026nbsp;\u003c/strong\u003eTaken from the Institute.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability Statement:\u003c/strong\u003e The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy and ethical reasons.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eDaniyal M, Siddiqui ZA, Akram M, Asif HM, Sultana S, Khan A (2014) Epidemiology, etiology, diagnosis and treatment of prostate cancer. Asian Pac J Cancer Prev 15:9575-9578. https://doi.org/10.7314/apjcp.2014.15.22.9575\u003c/li\u003e\n \u003cli\u003eLitwin MS, Tan HJ (2017) The Diagnosis and Treatment of Prostate Cancer: A Review. JAMA 317:2532-2542. https://doi.org/10.1001/jama.2017.7248\u003c/li\u003e\n \u003cli\u003eIlic D, Evans SM, Allan CA, Jung JH, Murphy D, Frydenberg M (2017) Laparoscopic and robotic-assisted versus open radical prostatectomy for the treatment of localised prostate cancer. Cochrane Database Syst Rev 9:CD009625. https://doi.org/10.1002/14651858.CD009625.pub2\u003c/li\u003e\n \u003cli\u003eRegan TC, Mordkin RM, Constantinople NL, Spence IJ, Dejter SW, Jr. (1996) Incidence of inguinal hernias following radical retropubic prostatectomy. Urology 47:536-537. https://doi.org/10.1016/s0090-4295(99)80491-9\u003c/li\u003e\n \u003cli\u003eAbe T, Shinohara N, Harabayashi T et al. (2007) Postoperative inguinal hernia after radical prostatectomy for prostate cancer. Urology 69:326-329. https://doi.org/10.1016/j.urology.2006.09.043\u003c/li\u003e\n \u003cli\u003eIchioka K, Yoshimura K, Utsunomiya N et al. (2004) High incidence of inguinal hernia after radical retropubic prostatectomy. Urology 63:278-281. https://doi.org/10.1016/j.urology.2003.09.038\u003c/li\u003e\n \u003cli\u003eLepor H, Robbins D (2007) Inguinal hernias in men undergoing open radical retropubic prostatectomy. Urology 70:961-964. https://doi.org/10.1016/j.urology.2007.08.038\u003c/li\u003e\n \u003cli\u003eLodding P, Bergdahl C, Nyberg M, Pileblad E, Stranne J, Hugosson J (2001) Inguinal hernia after radical retropubic prostatectomy for prostate cancer: a study of incidence and risk factors in comparison to no operation and lymphadenectomy. J Urol 166:964-967. https://doi.org/10.1016/s0022-5347(05)65874-0\u003c/li\u003e\n \u003cli\u003eSekita N, Suzuki H, Kamijima S et al. (2009) Incidence of inguinal hernia after prostate surgery: open radical retropubic prostatectomy versus open simple prostatectomy versus transurethral resection of the prostate. Int J Urol 16:110-113. https://doi.org/10.1111/j.1442-2042.2008.02190.x\u003c/li\u003e\n \u003cli\u003eStranne J, Johansson E, Nilsson A et al. (2010) Inguinal hernia after radical prostatectomy for prostate cancer: results from a randomized setting and a nonrandomized setting. Eur Urol 58:719-726. https://doi.org/10.1016/j.eururo.2010.08.006\u003c/li\u003e\n \u003cli\u003eTwu CM, Ou YC, Yang CR, Cheng CL, Ho HC (2005) Predicting risk factors for inguinal hernia after radical retropubic prostatectomy. Urology 66:814-818. https://doi.org/10.1016/j.urology.2005.04.034\u003c/li\u003e\n \u003cli\u003eChen HR, Ting HK, Kao CC et al. (2018) Robot-assisted radical prostatectomy may induce inguinal hernia within the first 2 years: An 11-year single-surgeon experience of \u0026gt;400 cases. Medicine (Baltimore) 97:e12208. https://doi.org/10.1097/MD.0000000000012208\u003c/li\u003e\n \u003cli\u003eKowalczyk KJ, Davis M, O\u0026apos;Neill J et al. (2020) Impact of Retzius-sparing Versus Standard Robotic-assisted Radical Prostatectomy on Penile Shortening, Peyronie\u0026apos;s Disease, and Inguinal Hernia Sequelae. Eur Urol Open Sci 22:17-22. https://doi.org/10.1016/j.euros.2020.09.004\u003c/li\u003e\n \u003cli\u003eKu JY, Lee CH, Park WY, Lee NK, Baek SH, Ha HK (2018) The cumulative incidence and risk factors of postoperative inguinal hernia in patients undergoing radical prostatectomy. Int J Clin Oncol 23:742-748. https://doi.org/10.1007/s10147-018-1244-0\u003c/li\u003e\n \u003cli\u003eLee DH, Jung HB, Chung MS, Lee SH, Chung BH (2013) Patent processus vaginalis in adults who underwent robot-assisted laparoscopic radical prostatectomy: predictive signs of postoperative inguinal hernia in the internal inguinal floor. Int J Urol 20:177-182. https://doi.org/10.1111/j.1442-2042.2012.03118.x\u003c/li\u003e\n \u003cli\u003eLiu L, Xu H, Qi F et al. (2020) Incidence and risk factors of inguinal hernia occurred after radical prostatectomy-comparisons of different approaches. BMC Surg 20:218. https://doi.org/10.1186/s12893-020-00883-9\u003c/li\u003e\n \u003cli\u003eMajima T, Yoshino Y, Matsukawa Y et al. (2018) Causative factors for de novo inguinal hernia after robot-assisted radical prostatectomy. J Robot Surg 12:277-282. https://doi.org/10.1007/s11701-017-0729-6\u003c/li\u003e\n \u003cli\u003eOtaki T, Hasegawa M, Yuzuriha S et al. (2021) Clinical impact of psoas muscle volume on the development of inguinal hernia after robot-assisted radical prostatectomy. Surg Endosc 35:3320-3328. https://doi.org/10.1007/s00464-020-07770-7\u003c/li\u003e\n \u003cli\u003eShimbo M, Endo F, Matsushita K et al. (2017) Incidence, Risk Factors and a Novel Prevention Technique for Inguinal Hernia after Robot-Assisted Radical Prostatectomy. Urol Int 98:54-60. https://doi.org/10.1159/000448339\u003c/li\u003e\n \u003cli\u003eYamada Y, Fujimura T, Fukuhara H et al. (2017) Incidence and risk factors of inguinal hernia after robot-assisted radical prostatectomy. World J Surg Oncol 15:61. https://doi.org/10.1186/s12957-017-1126-3\u003c/li\u003e\n \u003cli\u003eFujii Y, Yamamoto S, Yonese J et al. (2010) A novel technique to prevent postradical retropubic prostatectomy inguinal hernia: the processus vaginalis transection method. Urology 75:713-717. https://doi.org/10.1016/j.urology.2009.05.051\u003c/li\u003e\n \u003cli\u003eKoike H, Matsui H, Morikawa Y, Shibata Y, Ito K, Suzuki K (2013) Simple method for preventing inguinal hernias after radical retropubic prostatectomy. Prostate Int 1:76-80. https://doi.org/10.12954/PI.12009\u003c/li\u003e\n \u003cli\u003eSakai Y, Okuno T, Kijima T et al. (2009) Simple prophylactic procedure of inguinal hernia after radical retropubic prostatectomy: isolation of the spermatic cord. Int J Urol 16:848-851. https://doi.org/10.1111/j.1442-2042.2009.02370.x\u003c/li\u003e\n \u003cli\u003eTaguchi K, Yasui T, Kubota H et al. (2010) Simple method of preventing postoperative inguinal hernia after radical retropubic prostatectomy. Urology 76:1083-1087. https://doi.org/10.1016/j.urology.2010.05.002\u003c/li\u003e\n \u003cli\u003eLee DH, Koo KC, Lee SH, Chung BH (2014) A simple procedure to prevent postoperative inguinal hernia after robot-assisted laparoscopic radical prostatectomy: a plugging method of the internal inguinal floor for patients with patent processus vaginalis. J Urol 191:468-472. https://doi.org/10.1016/j.juro.2013.09.035\u003c/li\u003e\n \u003cli\u003eShimbo M, Endo F, Matsubara T, Shimada G, Hattori K (2022) Long-term results after robot-assisted radical prostatectomy of a simplified inguinal hernia prevention technique without artificial substance use. Int J Urol 29:1315-1321. https://doi.org/10.1111/iju.14989\u003c/li\u003e\n \u003cli\u003eFujii Y (2020) [Prevention of inguinal hernia after radical prostatectomy; overview] Zenritsusen zentekijojyutsu go no sokei hernia no yobou overview (in Japanese). Nihon Minimamu Sou Hinyouki Naishikyou Geka Gakkai zasshi 12:19-24\u003c/li\u003e\n \u003cli\u003eSoma T, Fukuda S, Matsuyama Y et al. (2023) Peritoneal closure and the processus vaginalis transection method to prevent inguinal hernia after robot-assisted radical prostatectomy. Int J Urol. https://doi.org/10.1111/iju.15170\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-robotic-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jors","sideBox":"Learn more about [Journal of Robotic Surgery](http://link.springer.com/journal/11701)","snPcode":"11701","submissionUrl":"https://submission.nature.com/new-submission/11701/3","title":"Journal of Robotic Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Inguinal hernia, Multicenter study, Prostate cancer, Radical prostatectomy, Robot-assisted radical prostatectomy","lastPublishedDoi":"10.21203/rs.3.rs-3153830/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3153830/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose: \u003c/strong\u003eTo investigate the incidence and risk factors of inguinal hernia (IH) after robot-assisted radical prostatectomy (RARP) using a multicentric database.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003eThe present study used a multicentric database (the MSUG94) containing data on 3,195 Japanese patients undergoing RARP between 2012 and 2021. Surgical procedures utilized for IH prevention were as follows: isolation of the vas deferens, transection the vas deferens, isolation of the spermatic vessels, and separation of the peritoneum from the internal inguinal ring. The primary and secondary endpoints were IH-free survival and any association between post-RARP IH and clinical covariates. The prophylactic effect of the above procedures were also assessed.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults: \u003c/strong\u003eIH prevention was attempted in 1,465 (46.4%) patients at five of the nine hospitals. During follow-up (median 24 months), post-RARP IH developed in 243 patients. The post-RARP IH-free survival rate at year 1, 2, and 3 was 94.3%, 91.7%, and 90.5%, respectively. Old age (hazard ratio [HR]: 1.037; 95% confidence interval [CI]: 1.014-1.061; \u003cem\u003ep\u003c/em\u003e = 0.001), low BMI (HR: 0.904; 95% CI: 0.863-0.946: \u003cem\u003ep\u003c/em\u003e \u0026lt;0.001), and low hospital volume (HR: 1.385; 95% CI: 1.003-1.902; \u003cem\u003ep\u003c/em\u003e = 0.048) were independently associated with IH development. None of the procedures for IH prevention were associated with IH development.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion: \u003c/strong\u003eOur findings may represent the current, real-world status of post-RARP IH in Japan. The prophylactic effects of the surgical procedures for IH prevention should be further investigated in well-designed, prospective studies to optimize the surgical technique.\u003c/p\u003e","manuscriptTitle":"Incidence and risk factors of inguinal hernia after robot-assisted radical prostatectomy: a retrospective multicenter cohort study in Japan (the MSUG94 group)","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2023-07-14 14:49:14","doi":"10.21203/rs.3.rs-3153830/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2023-09-01T14:36:51+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2023-08-28T16:00:29+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"0e64a4d2-b575-46e7-b3b6-e5a3a63a9611_SNPRID","date":"2023-08-23T06:50:22+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2023-08-19T14:45:13+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2023-07-16T18:52:57+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2023-07-10T13:37:24+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Robotic Surgery","date":"2023-07-09T13:07:18+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-robotic-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jors","sideBox":"Learn more about [Journal of Robotic Surgery](http://link.springer.com/journal/11701)","snPcode":"11701","submissionUrl":"https://submission.nature.com/new-submission/11701/3","title":"Journal of Robotic Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"0e1ba8ba-11a5-4064-a3b2-05a0e00cb07a","owner":[],"postedDate":"July 14th, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-01-22T15:07:07+00:00","versionOfRecord":{"articleIdentity":"rs-3153830","link":"https://doi.org/10.1007/s11701-023-01761-1","journal":{"identity":"journal-of-robotic-surgery","isVorOnly":false,"title":"Journal of Robotic Surgery"},"publishedOn":"2024-01-17 15:01:47","publishedOnDateReadable":"January 17th, 2024"},"versionCreatedAt":"2023-07-14 14:49:14","video":"","vorDoi":"10.1007/s11701-023-01761-1","vorDoiUrl":"https://doi.org/10.1007/s11701-023-01761-1","workflowStages":[]},"version":"v1","identity":"rs-3153830","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3153830","identity":"rs-3153830","version":["v1"]},"buildId":"pf3fE39SIOqb-0xH_OWvX","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}