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Incidence of Inguinal Hernia after Radical Prostatectomy: A Systematic Review and Meta-Analysis

2019; Lippincott Williams & Wilkins; Volume: 203; Issue: 2 Linguagem: Inglês

10.1097/ju.0000000000000313

1527-3792

Rasmus Alder, Dennis Zetner, Jacob Rosenberg,

Prostate Cancer Diagnosis and Treatment

You have accessJournal of UrologyReview Article1 Feb 2020Incidence of Inguinal Hernia after Radical Prostatectomy: A Systematic Review and Meta-Analysis Rasmus Alder, Dennis Zetner, and Jacob Rosenberg Rasmus AlderRasmus Alder *Correspondence: Center for Perioperative Optimization, Department of Surgery, Herlev and Gentofte Hospitals, University of Copenhagen, Herlev Ringvej 75, DK-2730Herlev, Denmark E-mail Address: [email protected] Center for Perioperative Optimization, Department of Surgery, Herlev and Gentofte Hospitals, University of Copenhagen, Herlev, Denmark , Dennis ZetnerDennis Zetner Center for Perioperative Optimization, Department of Surgery, Herlev and Gentofte Hospitals, University of Copenhagen, Herlev, Denmark , and Jacob RosenbergJacob Rosenberg Center for Perioperative Optimization, Department of Surgery, Herlev and Gentofte Hospitals, University of Copenhagen, Herlev, Denmark View All Author Informationhttps://doi.org/10.1097/JU.0000000000000313AboutAbstractPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail Abstract Purpose: To investigate the incidence of inguinal hernia following radical prostatectomy we compared the incidence after open retropubic radical prostatectomy with the incidence after the laparoscopic and robot-assisted radical prostatectomies, and using control groups. Materials and Methods: We included all original articles on studies providing data on inguinal hernia incidence in patients treated with radical prostatectomy for localized prostate cancer. PubMed® and EMBASE® were searched on February 28, 2018. A meta-analysis was done as a weighted and pooled estimate of the incidence of inguinal hernia. The bias risk was assessed using the Newcastle-Ottawa Scale for cohort studies and the Cochrane Collaboration tool for randomized clinical trials. Results: We included 54 studies with a total of 101,687 patients. The estimated incidence of inguinal hernia was 13.7% (95% CI 12.0–15.4) after open retropubic radical prostatectomy, 7.5% (95% CI 5.2–9.8) after laparoscopic radical prostatectomy and 7.9% (95% CI 5.0–10.9) after robot-assisted laparoscopic radical prostatectomy. In studies comparing the incidence of inguinal hernia after open prostatectomy vs no treatment the incidence was significantly higher in the radical prostatectomy group (11.7%, 95% CI 9.2–14.2 vs 3.3%, 95% CI 2.0–4.6). Two of 3 studies showed a significantly higher incidence after laparoscopic and robot-assisted radical prostatectomies compared with a control group. Most studies of intraoperative inguinal hernia prevention techniques demonstrated a significantly lower inguinal hernia incidence in the experimental group. Inguinal hernias that developed after radical prostatectomy were primarily indirect (81.9%, 95% CI 75.3–88.4). Conclusions: We found a high incidence of inguinal hernia following radical prostatectomy and hernias were primarily of the indirect type. The highest incidence of inguinal hernia was noted after open radical prostatectomy, followed by laparoscopic and robot-assisted radical prostatectomies. There was no significant difference between the laparoscopic and robot-assisted groups. The incidence of inguinal hernia was significantly higher after open radical prostatectomy than in control groups with some evidence to support the same finding for the laparoscopic and robot-assisted approaches. Promising results have been reported in studies of intraoperative prophylactic surgical techniques to reduce the postoperative incidence of inguinal hernia. Prostate cancer is the most common form of cancer in men.1 The localized form of prostate cancer can be treated with curative intent with radical prostatectomy.2 Historically radical prostatectomy has been performed as open retropubic radical prostatectomy, which has now almost entirely been replaced by minimally invasive procedures, including laparoscopic and robot-assisted laparoscopic radical prostatectomy.3 The most common complications after radical prostatectomy are urinary incontinence and impotence.2,4 However, inguinal hernia is another recognized complication of radical prostatectomy. Thus, in a study of 92 patients an inguinal hernia developed in 11 (12%) within 6 months after surgery.5 This was confirmed in several subsequent studies showing an incidence of 6.1% to 22.0%.6–8 In 2013 the first systematic review was done on the incidence of inguinal hernia after radical prostatectomy with a meta-analysis of the risk factors and prevention of inguinal hernia.9 Since then, numerous individual studies have been published on inguinal hernia after radical prostatectomy, especially robot-assisted laparoscopic radical prostatectomy. The aim of this systematic review was to investigate the incidence of inguinal hernia in men after radical prostatectomy of localized prostate cancer. We wanted to investigate whether there would be a difference in the inguinal hernia incidence after open retropubic radical prostatectomy compared with laparoscopic and robotic radical prostatectomies. We also sought to investigate the incidence of inguinal hernia after radical prostatectomy compared with control groups and explore the efficacy of potential intraoperative inguinal hernia prevention techniques. Furthermore, we wanted to investigate the time from radical prostatectomy to inguinal hernia diagnosis or repair, the anatomy of inguinal hernia, and whether reported inguinal hernia incidences would correlate with followup methods. Materials and Methods This systematic review and meta-analysis was reported according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses).10 A protocol was registered in PROSPERO (No. CRD42018095987). We used the PICOS (Patient, Problem of Population, Intervention, Comparison, Control or Comparator, Outcome[s], Study Type) criteria to select articles. Population included all men with localized prostate cancer who had undergone radical prostatectomy. Interventions included any type of radical prostatectomy (open retropubic, laparoscopic or robot-assisted laparoscopic). Comparison groups were not required. Outcome included the incidence of inguinal hernia after radical prostatectomy. Study design included all original articles except case reports. A systematic search was done in PubMed® and EMBASE® with PubMed covering articles from 1946 to the present and EMBASE covering 1974 to the present. A search string was formulated in collaboration with an information specialist at the Royal Danish University Library. The search was performed on February 28, 2018. The full search string in PubMed was (("prostatectomy"[MeSH Terms] OR "prostatectomy"[All Fields]) OR ((("prostate"[MeSH Terms] OR "prostate"[All Fields]) OR ("prostate"[MeSH Terms] OR "prostate"[All Fields] OR "prostatic"[All Fields])) AND (("neoplasms"[MeSH Terms] OR "neoplasms"[All Fields] OR "cancer"[All Fields]) OR ("neoplasms"[MeSH Terms] OR "neoplasms"[All Fields])))) AND ("hernia"[MeSH Terms] OR "hernia"[All Fields]). The search string was adapted to fit the search in EMBASE. Additional studies found in reference lists of included studies were screened for eligibility. Studies found in this search were uploaded to Covidence and duplicates were removed using the Covidence tool.11 Using Covidence 2 of us independently screened titles, abstracts and full texts. Discrepancies were resolved by discussion between the 2 authors. Data from the included articles were extracted and entered in a predefined table in a Microsoft® Office Excel® 2016 sheet by one of us (RA), who doublechecked all data entries for typing errors. The extracted data variables were study design, surgical technique, number of participants, followup type, followup period, inguinal hernia incidence, time from radical prostatectomy to inguinal hernia diagnosis or repair and inguinal hernia anatomy, ie an indirect or a direct type of inguinal hernia. Table. Studies with inguinal hernia prevention techniques as comparison Hernia prophylaxis method (reference) Conventional Hernia Prevention Followup (mos) No. Pts No. Hernia (%) No. Pts No. Hernia (%) Conventional Hernia Prevention Spermatic cord isolation: 24 156 30 (19.0) 67 2 (3.0) Median 36 (range 3–58) Median 36 (range 3–58) 26* 109 27 (24.8) 178 33 (18.5) Median 75.9 (range 24–107)† Median 52.2 (range 26–79)† 43 170 20 (11.8) 101 0 Median 23.9 (range 23–24)† Median 11.6 (range 2–22)† 60 171 42 (24.6) 150 22 (14.7) 63.5† 21.6† 62‡ 72 14 (19.4) 89 2 (2.2) Mean ± SD 23.5 ± 6.1† Mean ± SD 14.0 ± 3.9† 63 20 10 (50.0) 62 1 (1.6) Median 41 (range 1–73) Median 41 (range 25–59) Processus vaginalis transection: 25 228 41 (18.0) 196 4 (2.0) Median 74.4 (range 3–156) Median 74.4 (range 3–156) 26* 109 27 (24.8) 57 0 Median 75.9 (range 24–107) Median 36.7 (range 24–30) 58 115 18 (15.7) 115 1 (0.9) Mean ± SD 46.2 ± 17.6† Mean ± SD 26.0 ± 7.6† 59 433 109 (25.2) 435 4 (0.9) Mean ± SD 60.6 ± 33.7† Mean ± SD 40.6 ± 13.5† 62 107 25 (23.0) 73 3 (4.1) 88.0† 21.0† Figure-of-8 suture (64) 127 12 (9.1)§ 127 9 (3.5)§ Median 37.7 (range 27–56) Median 37.7 (range 27–56) Internal inguinal floor plugging (36)‡ 47‖ 16 (34)‖ 51 0 Mean ± SD 13.8 ± 8.5 Mean ± SD 11.8 ± 6.2 Conventional open retropubic radical prostatectomy vs spermatic cord isolation and processus vaginalis transection methods. Significantly different conventional vs inguinal hernia prevention group followups. Robot-assisted laparoscopic radical prostatectomy Kaplan-Meier 36-month estimate. Reported only as groins. The study primary outcome was the incidence of inguinal hernia after radical prostatectomy. Secondary outcomes were the incidence of inguinal hernia compared with control groups or with patients treated intraoperatively with inguinal hernia prevention techniques, time from radical prostatectomy to inguinal hernia diagnosis or treatment, anatomy of the inguinal hernia and the correlation between the reported inguinal hernia incidence and the followup method. If a study did not mention the incidence but only the number of patients in whom inguinal hernia developed, the incidence was calculated as the cumulative incidence proportion. If only the cumulative incidence proportion was reported for a population, the corresponding number of patients was calculated. Inguinal hernia diagnosis rates, inguinal hernia repair rates and Kaplan-Meier estimates reported as the estimated cumulative incidence or estimated inguinal hernia-free survival were converted to cumulative inguinal hernia incidence proportions to standardize data for use in meta-analyses. The risk of bias in nonrandomized observational studies was assessed using the NOS (Newcastle-Ottawa Scale).12 The studies received 0 to 9 stars with a low number of stars representing a high risk of bias. The risk of bias of each study was assessed in regard to our primary outcome and not in regard to the primary outcome in the assessed article. The risk of bias in randomized controlled trials was assessed using the Cochrane Collaboration tool.13 We performed a meta-analysis of the incidence of inguinal hernia after radical prostatectomy. The meta-analysis was a proportion analysis in which the reported incidence in each study had a 95% CI estimated and each study was weighted based on the number of participants. Thus, the result of the meta-analysis was a pooled and weighted estimate of the incidence with the 95% CI. In the meta-analyses we used the binary random effects model and the DerSimonian-Laird method. Forest plots were constructed to provide a graphic presentation. All statistical analyses were done with OpenMeta[Analyst], version 0.1504.14 A difference in the inguinal hernia incidence was considered statistically significant when the estimated 95% CIs did not overlap. Results Study Selection and Characteristics Figure 1 shows the number of articles screened, eligibility assessment and reasons for exclusion. A total of 54 studies were included in this systematic review.5–8,15–64 The supplementary table (https://www.jurology.com) presents the baseline characteristics of the included studies. There were 2 randomized controlled trials8,64 and 52 cohort studies.5–7,15–63 Of the 52 cohort studies 35 were retrospective5–7,15–46 and 17 were prospective.8,47–64 Ten studies had control groups for comparison7,8,28–34,55 and 13 investigated 4 types of intraoperative inguinal hernia prevention techniques.8,23–26,36,43,58–63 As a primary outcome 45 studies had inguinal hernia after radical prostatectomy5–8,20–48,53–64 and 9 had a different primary outcome.15–19,49–52 Figure 1. PRISMA flowchart of search, screening and selection process. The 54 studies included in qualitative analysis included a total of 101,687 patients who underwent radical prostatectomy.5–8,15–64 In studies comparing radical prostatectomy with control groups a total of 142,191 patients served as controls. In studies comparing radical prostatectomy with and without an inguinal hernia prevention technique 1,864 patients treated with conventional radical prostatectomy were compared with 1,701 who underwent an additional inguinal hernia prevention technique. Inguinal Hernia Incidence After Radical Prostatectomy We performed a meta-analysis to estimate the weighted pooled incidence of inguinal hernia after each surgical approach. After open retropubic radical prostatectomy the pooled incidence of inguinal hernia was 13.7% (5,445 of 56,620 cases, 95% CI 12.0–15.4) with an incidence range of 2.5% to 50% (supplementary figure, https://www.jurology.com). After laparoscopic radical prostatectomy the pooled incidence of inguinal hernia was 7.5% (99 of 1,332 cases, 95% CI 5.2–9.8) with an incidence range of 5.2% to 14.0% (fig. 2). After robot-assisted laparoscopic radical prostatectomy the pooled incidence was 7.9% (1,468 of 13,018 cases, 95% CI 5.0–10.9), with an incidence range of 3.0% to 19.4% (fig. 3). There was no significant difference between the laparoscopic and robot-assisted radical prostatectomy groups. Figure 2. Forest plot of each inguinal hernia incidence after laparoscopic radical prostatectomy. Study column shows reference numbers. Dashed red line indicates pooled and weighted estimated incidence from meta-analysis. Blue diamond represents 95% CI. Figure 3. Forest plot of each inguinal hernia incidence after robot-assisted laparoscopic radical prostatectomy. Dashed red line indicates pooled and weighted estimated incidence from meta-analysis. Blue diamond represents 95% CI. Some studies provided the incidence of inguinal hernia after retropubic, laparoscopic and/or robot-assisted laparoscopic radical prostatectomy. Thus, the supplementary table (https://www.jurology.com) lists these studies more than once, although they were done in different unique populations unless otherwise specified. Two studies investigated the incidence of inguinal hernia after all 3 types of surgical approach but they only reported an overall incidence in the entire population so that data from these studies were not used in the meta-analysis.27,54 Another study reported a combined incidence for incisional and inguinal hernia of 88 of 3,477 cases (2.5%).50 The corresponding author was contacted and replied that there were only a few incisional hernia cases and, therefore, we included these results in our analysis as inguinal hernias. Two studies reported a combined incidence of inguinal hernia after minimally invasive radical prostatectomy, which consisted of pure laparoscopic and robot-assisted laparoscopic radical prostatectomy approaches.15,31 The corresponding authors were contacted and 1 author replied that no data were available on the number of patients in each approach and, thus, we could not include these data sets in our meta-analysis. The 2 studies also reported open retropubic radical prostatectomy and were included in analysis. One study used a part of the same population of an earlier study by the same first author as comparison group with their inguinal hernia prevention technique.28,60 Therefore, we only used data on the same population once for inguinal hernia incidence estimates. Another 2 studies used the same inclusion period in the same database when reporting inguinal hernia repair rates. It was assumed that these populations were identical, although there was a slightly different number of patients.30,33 Therefore, we chose to discard the data from the study with the highest risk of bias from the meta-analysis.33 Two studies extracted data from the same national prostate cancer database, of which 1 included patients from 1998 to 201031 and the other included patients from 2004 to 2013.17 We assumed that a proportion of the included patients was identical. For the meta-analysis on the incidence of inguinal hernia after open radical prostatectomy we only used data from the study with the lowest risk of bias which also included the most patients.31 However, we used data from the first study in the meta-analysis on the incidence of inguinal hernia after robot-assisted laparoscopic radical prostatectomy since data were specified as robot-assisted and not only as minimally invasive.17 There were also 3 consecutive studies on robot-assisted laparoscopic radical prostatectomy with the same first author and the same inclusion period starting point.35–37 Thus, we assumed that the most recent of these studies had included all patients who were also in the first 2 studies and only data from the most recent study were included in statistical analysis.37 The first of these studies reported the anatomy of the inguinal hernia.35 Radical Prostatectomy vs Control Groups We found 10 studies with a control group for comparison. Nine studies reported the incidence of inguinal hernia after open retropubic radical prostatectomy,7,8,28,30–34,55 of which 28,31 and 129 included the incidence of inguinal hernia after laparoscopic and robot-assisted laparoscopic radical prostatectomy. We performed a meta-analysis of 8 open retropubic radical prostatectomy studies and included the control groups, which consisted of patients who did not receive surgical treatment but instead underwent external beam radiation therapy, radiotherapy, transurethral prostate resection, prostate biopsy or watchful waiting as well as age matched men in the background population. We excluded control groups in which patients underwent other lower midline surgical procedures because of the risk that these procedures would themselves cause inguinal hernias. One study was excluded from meta-analysis because it was done in the same population as in another of the included studies as described.33 The meta-analysis revealed a pooled and weighted estimate of the incidence of inguinal hernia after open retropubic radical prostatectomy of 11.7% (2,867 of 22,734 cases, 95% CI 9.2–14.2, fig. 4). In the control groups the incidence was 3.3% (5,212 of 121,408 cases, 95% CI 2.0–4.6, fig. 5). We performed sensitivity analysis to test for the effect of 1 study with a different control group than the other studies.31 That study was done in an age matched background population of men without prostate cancer as the control group, in contrast to control groups in the other studies, which consisted of patients with prostate cancer who received treatments other than surgery. Sensitivity analysis revealed that the control group with an age matched background population without prostate cancer did not change the outcome of the meta-analysis and when the study was not included in the analysis, the pooled incidence was 3.2% (996 of 15,986 cases, 95% CI 1.2–5.1).31 This study also reported the combined incidence of inguinal hernia after laparoscopic and robot-assisted radical prostatectomy. It showed a 10% incidence rate after 6 years compared to 4% in the control group, resulting in a HR of 3.37 (95% CI 2.92–3.83).31 Figure 4. Forest plot of inguinal hernia incidence after open retropubic radical prostatectomy in studies with control groups. Study column shows reference numbers. Dashed red line indicates pooled and weighted estimated incidence from meta-analysis. Blue diamond represents 95% CI. Figure 5. Forest plot of inguinal hernia incidence in control groups included in meta-analysis. Study column shows reference numbers. Dashed red line indicates pooled and weighted estimated incidence from meta-analysis. Blue diamond represents 95% CI. One study compared open radical and robot-assisted laparoscopic radical prostatectomy, and an age matched, background control group.8 On Kaplan-Meier analysis the 48-month incidence rate of inguinal hernia was 12.2% (95% CI 9.0–16.4) after open radical prostatectomy, 5.8% (95% CI 4.0–8.3) after robot-assisted radical prostatectomy and 4.4% (95% CI 1.8–10.7) in the control group. The log-rank (Mantel-Cox) test in the robot-assisted radical prostatectomy group vs the control group revealed no significant difference between the 2 groups (p=0.065). Another study compared laparoscopic and robot-assisted laparoscopic radical prostatectomy with a control group of patients who underwent transurethral resection of bladder tumor.29 The inguinal hernia incidence was 5.3% after laparoscopic radical prostatectomy, 4.2% after robot-assisted radical prostatectomy and 0.5% in the control group. The log rank test revealed a significant difference between the laparoscopic and robot-assisted laparoscopic radical prostatectomy groups, and the control group (p <0.001). However, there was no difference between the laparoscopic and robot-assisted groups. In studies with Kaplan-Meier estimates and control groups we noted that after the initial 2 to 3 years there was a tendency for the risk of inguinal hernia to return to baseline or to a level comparable to that in the control groups.7,8,28,30,32,55 However, no study provided any analysis to support this. Radical Prostatectomy with vs without Hernia Prevention Techniques We found 12 studies investigating 2 inguinal hernia prevention techniques, including the spermatic cord isolation method23,24,26,43,60,62,63 and the processus vaginalis transection method.25,26,36,58,59,61 The spermatic cord isolation method focused on the internal inguinal ring area with blunt dissection of the peritoneum and subsequent isolation of the spermatic cord from the surrounding peritoneum at the internal inguinal ring via a preperitoneal approach.63 The processus vaginalis transection method included the entire first method described with subsequent dissection of the vas deferens from the spermatic cord. When present, the processus vaginalis was identified and dissected free of other spermatic cord elements and then transected and ligated just distal to the peritoneum.47 Another study investigated the effect of a simple figure-of-8 suture at the internal inguinal ring64 and 1 investigated the effect of plugging the internal inguinal floor with hemostatic agents.36 The table lists individual study results. In patients treated with the spermatic cord isolation method the pooled and weighted estimate of incidence of inguinal hernia was 6.1% (60 of 647 cases, 95% CI 1.7–10.6). In patients treated with the processus vaginalis transection method the pooled and weighted estimate of the incidence of inguinal hernia was 1.1% (12 of 876, 95% CI 0.4–1.8). One study of the spermatic cord isolation and the processus vaginalis transection methods compared them in a cohort treated with conventional radical prostatectomy and found that the processus vaginalis transection method was superior to the spermatic cord isolation method.26 Inguinal hernia developed in 24.8% of patients in the no prophylaxis group, in 18.5% in the spermatic cord isolation method group and in none in the processus vaginalis transection method group. Overall 10 of the 13 studies revealed a significantly lower rate of inguinal hernia after an intraoperative inguinal hernia prevention technique was applied compared with the conventional radical prostatectomy group.23,24,26,36,43,58,59,61–63 Three studies showed no significantly lower incidence of inguinal hernia.25,28,64 Seven of the 13 studies reported significantly longer followup in the conventional prostatectomy groups than in the experimental groups (see table).26,43,58–62 Inguinal Hernia Secondary Outcomes Time from Radical Prostatectomy to Diagnosis or Repair The supplementary table (https://www.jurology.com) lists studies showing the time from radical prostatectomy to inguinal hernia diagnosis or repair. Due to the high degree of heterogeneity in reported data across the studies, it was unfeasible to combine them into 1 estimate. However, we found that most inguinal hernias developed within the first 2 to 3 years after radical prostatectomy. Postoperative Anatomy All studies reported that inguinal hernias were primarily indirect. The meta-analysis revealed that when pooled, the proportion of indirect inguinal hernias was 81.9% (2,208 of 2,913 cases, 95% CI 75.3–88.4, fig. 6). All surgical approach types were included in the meta-analysis. Figure 6. Forest plot of proportion of indirect inguinal hernias. Study column shows reference numbers. Dashed red line indicates pooled and weighted estimated incidence from meta-analysis. Blue diamond represents 95% CI. Incidence Difference Based on Followup Method The supplementary table (https://www.jurology.com) presents study followup methods. Across the studies there were numerous designs, followup methods and ways that inguinal hernias were diagnosed. In many studies this information was poorly reported or not reported at all. Because of these challenges, we chose not to perform this subgroup analysis. Because of differences in study design, followup method and the method of inguinal hernia detection across the studies, an analysis of the difference in the inguinal hernia incidence based on the followup method was not feasible. One study compared a patient file survey and a patient administered questionnaire based on the reported inguinal hernia incidence and found that the patient file survey was inferior to a validated questionnaire to report the inguinal hernia incidence.56 Bias Two randomized controlled trials were included in this systematic review.8,64 The risks of bias included random sequence generation high and unclear risk, allocation concealment high and low risk, low blinding of participants and personnel for both, low blinding of outcome assessment for both, low incomplete outcome data for both, selective reporting unclear for both and other sources of bias unclear and low, respectively, in the 2 randomized controlled trials. There were 52 cohort studies5–7,15–50,52–63 and they had a median risk of bias of 6 stars (range 2 to 8) according to the NOS. Discussion We found a higher incidence of inguinal hernia after open retropubic radical prostatectomy than after laparoscopic and after robot-assisted laparoscopic radical prostatectomy (13.6% vs 7.5% and 7.9%, respectively). There was no difference between laparoscopic and robot-assisted radical prostatectomies. The incidence of inguinal hernia was higher after open retropubic radical prostatectomy than in patients who did not undergo surgery. Evidence points to the same conclusion for the laparoscopic and robot-assisted approaches but only 2 of the 3 available studies support this. Numerous groups have reported the promising results of different intraoperative prophylactic surgical interventions to reduce or eliminate postoperative development of inguinal hernia. Inguinal hernias after radical prostatectomy were primarily indirect hernias. There are several strengths to our systematic review. The screening and selection process was systematic and done independently by 2 of us. We included all original articles with a reported inguinal hernia incidence after any type of radical prostatectomy. We included numerous studies in a total of more than 100,000 patients. Only 1 other systematic review on inguinal hernia after radical prostatectomy has been done with an emphasis on risk factors and prevention.9 Since then, numerous studies have been published on this subject, especially regarding the laparoscopic and robot-assisted surgical approaches. A limitation to our systematic review was overweighing of retrospective studies of the medical records of patients with varying followup periods. For these studies it was unknown whether the examining physician was aware of inguinal hernia as a postoperative complication or whether a check had been done for this condition. Most studies including intraoperative inguinal hernia prevention techniques showed a lower hernia rate than in the conventional surgical group. However, most of these studies had shorter followup in the experimental group than in the control group. To provide the best comparison and reduce the risk of bias, followup must be similar in the exposed and nonexposed cohorts.65 In some studies the prevention technique was implemented in all patients starting at 1 time point. Because the study design was retrospective, this resulted in a longer followup in patients in the conventional method group. Since an inguinal hernia can develop without prostatectomy as the underlying cause and patients are then followed for a longer period, this may result in a higher incidence in the comparison group. There is a high risk of bias in studies with a followup of less than 2 years or with a significantly shorter followup in the intervention or experimental group than in the control group. Future studies should report the incidence of inguinal hernia at specific points in time, eg at 1 year or 2, 3 and 5 years, whenever it is possible, to provide better data for comparisons and meta-analyses. A limitation to our meta-analysis is the heterogeneity across studies, which entailed uncertainty for the pooled estimates. Another possible limitation is the possibility of a higher incidence in earlier studies. However, when ordering the included studies chronologically, we observed no apparent correlations between earlier studies and a higher incidence. The wide followup range across studies also contributed to the uncertainty of the estimate. However, we chose to perform the meta-analysis because we believe that it provides the best estimate when including all currently available data. Conclusions Inguinal hernia is a postoperative complication specific to radical prostatectomy and our systematic review provides strong evidence to support this. We found a high incidence of inguinal hernia after open radical prostatectomy, followed by laparoscopic and robot-assisted radical prostatectomy. The incidence after open radical prostatectomy was statistically significantly higher than in the control groups. Some evidence supports the same conclusion for the laparoscopic and robot-assisted approaches but this needs to be further investigated. The inguinal hernias typically developed within the first 2 to 3 years and they were primarily indirect. It would be interesting to investigate whether the risk of inguinal hernia decreases after the first 2 years to a level comparable to that in the background population. Implementing intraoperative prevention techniques may be a way to reduce the incidence of inguinal hernia after radical prostatectomy. Based on the available data the best way seems to be preperitoneal transection of a patent processus vaginalis performed simultaneously with prostatectomy. 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Link, Google Scholar The corresponding author certifies that, when applicable, a statement(s) has been included in the manuscript documenting institutional review board, ethics committee or ethical review board study approval; principles of Helsinki Declaration were followed in lieu of formal ethics committee approval; institutional animal care and use committee approval; all human subjects provided written informed consent with guarantees of confidentiality; IRB approved protocol number; animal approved project number. Supplementary references 51 to 65 are available at https://www.jurology.com. No direct or indirect commercial, personal, academic, political, religious or ethical incentive is associated with publishing this article. © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue 2February 2020Page: 265-274Supplementary Materials Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.Keywordsrobotic surgical procedureslaparoscopyprostateprostatectomyherniainguinalAcknowledgmentTobias Wirenfeldt Klausen, Herlev Hospital, Denmark, assisted with the statistical analysis.MetricsAuthor Information Rasmus Alder Center for Perioperative Optimization, Department of Surgery, Herlev and Gentofte Hospitals, University of Copenhagen, Herlev, Denmark *Correspondence: Center for Perioperative Optimization, Department of Surgery, Herlev and Gentofte Hospitals, University of Copenhagen, Herlev Ringvej 75, DK-2730Herlev, Denmark E-mail Address: [email protected] More articles by this author Dennis Zetner Center for Perioperative Optimization, Department of Surgery, Herlev and Gentofte Hospitals, University of Copenhagen, Herlev, Denmark More articles by this author Jacob Rosenberg Center for Perioperative Optimization, Department of Surgery, Herlev and Gentofte Hospitals, University of Copenhagen, Herlev, Denmark More articles by this author Expand All The corresponding author certifies that, when applicable, a statement(s) has been included in the manuscript documenting institutional review board, ethics committee or ethical review board study approval; principles of Helsinki Declaration were followed in lieu of formal ethics committee approval; institutional animal care and use committee approval; all human subjects provided written informed consent with guarantees of confidentiality; IRB approved protocol number; animal approved project number. Supplementary references 51 to 65 are available at https://www.jurology.com. No direct or indirect commercial, personal, academic, political, religious or ethical incentive is associated with publishing this article. Advertisement Advertisement PDF downloadLoading ...