RALP has become a commonplace surgical approach for local prostate cancer over the last decade [12]. Recent evidence demonstrated that RALP was associated with better intraoperative outcomes compared to laparoscopic radical prostatectomy (LRP) [13], although high volume center became a requirement for better outcomes [14]. However, RP including RALP sometimes leads to PIH, which is painful and affects the patient’s quality of life. The reported incidence rate of PIH was 3.4%–7.3% after RALP and 8.4% after open RP [15,16]. PIH occurs within the first three years after RP [17]. A large nationwide population-based study also demonstrated that no significant difference was found regarding the risk of PIH between RP and RALP in 11,212 patients [18]. Generally, patients who previously underwent robot-assisted surgery tend to desire robot-assisted surgery for another surgery. The present study therefore aimed to evaluate whether R-TAPP was available for PIH.
Well-known risk factors for developing PIH include older age, previous inguinal hernia repair, and low BMI [19,20]. Moreover, Otaki et al. showed that psoas muscle volume (PMV) < 350 cm3 was an independent risk factor for PIH [21]. Additionally, Iwamoto et al. showed that dilatation of the internal inguinal ring represents an important risk factor for PIH [22]. The precise mechanism of developing PIH is still unknown, but it is definitive that a surgical procedure is a crucial factor in the development of PIH. A presently accepted theory is that a potentially existing vaginal process of the peritoneum becomes clinically evident because of peritoneal dissection around the internal inguinal ring [23]. Therefore, indirect inguinal hernia is the most frequent hernia type of PIH [24,25]. There is present data to support the relevance of this hypothesis.
Regarding prophylactic methods, Kadono et al. reported that dissection of the peritoneum from the internal inguinal ring, and separating the spermatic cord and vessels from the peritoneum, could reduce the incidence of PIH following RALP; however, they did not acquire statistical significance [26]. In contrast, Iwamoto et al. described creating an incisional line of peritoneum as an important prophylactic method. They proposed that incising the peritoneum sufficiently close to the internal inguinal ring could prevent PIH [22].
Regarding treatment in patients with histories of pelvic or abdominal surgeries including RP inguinal hernia repair, such as transabdominal preperitoneal (TAPP) and totally extra peritoneal (TEP) repair, may be difficult because of the need to dissect peritoneal adhesions, unlike in patients without surgical histories. Izadipani et al. showed that L-TAPP for PIH has good results and is effective [27]. In addition, Dulucq et al. reported that L-TEPP for PIH can be performed efficiently and safely in patients after RP by skilled and experienced laparoscopic surgeons [28]. Moreover, Sakon et al. showed that L-TAPP inguinal hernia repair after RALP was comparably safer and more effective than open surgery. They concluded that L-TAPP repair may be a valuable alternative to open hernioplasty [29]. In contrast, Angus et al. showed that R-TAPP might be an alternative to open repair in patients with a history of prior urologic pelvic operation [30]. Additionally, Bitnner and Leblanc et al. reported that operation times were longer for robotic hernia repair patients than laparoscopic patients, but there was no difference in the safety [31,32]. Under such conditions, the safety of R-TAPP for PIH has not been established. To our knowledge, there is no evidence that R-TAPP is a useful and safe procedure for PIH. Thus, in this study, we reviewed 16 cases of R-TAPP for PIH and evaluated their surgical outcomes in comparison with 54 cases of R-TAPP for non-PIH. R-TAPP was first introduced in our department in September 2016 under the mentorship of professor Kudsi [33]. Thus, we perform R-TAPP according to his instructions. The point to ponder is that R‐TAPP is still not covered by Japanese health insurance. Therefore, surgical cost will become an obstacle to patients with inguinal hernias and thereby make patient recruitment for R‐TAPP difficult in Japan. However, several institutions have gradually shown evidence of spread of R-TAPP in Japan [34].
The fact that R-TAPP is a more suitable surgical technique for PIH may lead to its increased demand and popularity. On the other hand, Prabhu et al. exhibited no clinical benefit to the robotic approach for straightforward inguinal hernia repair compared with the laparoscopic approach. They concluded that the robotic approach incurred higher costs and longer operation time compared with the laparoscopic approach [35]. Additionally, Kohraki et al. revealed that the outcomes of L-TAPP were significantly superior to the R-TAPP and at lower hospital costs [36]. In contrast, Forrester et al. reported that short-term quality of life after R-TEPP was improved compared to open and laparoscopic repairs. Thus, although the relative merit by approach for inguinal hernia repair is still controversial, we believe that the clinical benefit of robotic surgery is the multiarticular function of ease of performing peritoneal suturing compared to L-TAPP. However, our study has several noteworthy limitations. First, the relatively small number of PIH cases may cause a lack of statistical power. Next, our data were from a retrospective cohort study and collected at a single hospital. Thereafter, a more comprehensive prospective study should be conducted to confirm our findings in the near future.