Since its initial report on a series of 190 patients by Kumar et al. , the adoption of RALP in India has been on the rise. With its small incision, RRP remains the procedure of choice for most centres in India due to its cost-effectiveness. We got access to the robotic surgery in the second half of 2011, and from then on majority of the RPs are done robotically; however, open RRPs are still performed by the author (JNK). In the last 25years (1996–2021), we performed RRPs till 2011 and RALPs after that. Further, we used two types of robots (SI and SHD). Therefore, we had the chance to compare two large cohorts and report our observations. We also believe our series has the most extensive comparison of RALP with RRP by a single surgeon in India.
Demographic and preoperative parameters (Table 1) did not show significant variation in the two patient cohorts despite the patient populations being diagnosed in different periods, except that the number of operations has increased over time. Surgical technique-wise (Table 2), RALP clearly showed a significant reduction in blood loss and transfusion rates. Reasons postulated are- enhanced visualisation of prostatic apex, exact visualisation of the dorsal venous complex for passage of ligature, and the effect of pneumoperiperitoneum. Reported blood loss in studies ranges from 50-2500ml.[14, 15] Our study concurs with literature that RALP is advantageous in blood loss and transfusion rates. mean surgical duration for RALP reported previously ranges from 105-540min [16, 17]. However, in our series, operative time was significantly longer in RALP than RRP, which could be accounted for the time required for docking and getting acquainted with the robotic platform, the learning curve and initial experience by the surgical team.
Early recovery, minimal ileus and improved pain control contributed to the statistically significant impact on mean hospital stay between the two groups, which is in keeping with the previous studies. [14, 18] This is due to rapid recuperation offered by improved pain control. However, our mean length of stay is longer (four days) than most series due to patient preference. Ward expenses in Indian patients undergoing RALP are covered by private health insurance in major cities, which partly contributes to the longer stay. Moreover, some patients prefer going home catheter-free. In the study by Strother et al. , 90% of the cases studied were discharged home within days 0–2. Nelson et al. reported no significant difference between LOS of RRP and RALP patients (1.09 vs 1.03 days).
The catheter duration between the RALP and RRP patients in our study was statistically significant, in favour of RALP patients. Rocco et al. reported that the clinical importance of the difference in catheter duration between robotic and open prostatectomy was limited.
We used Clavien Dindo classification (Tables 3 and 4) as a standardised tool to compare our complications. The difference in the complications between the two groups in our study was not statistically significant. In a prospective trial by Di Pierro et al.  significant complication rates for RRP and RALP were 28% and 7%, respectively; minor complication rates were 24% and 35%, respectively. Ryu et al. reported fewer Clavien III complications in RALP than RRP.The difference in the urine leak in the two cohorts was not significant in our study. However, we stopped doing a routine cystogram prior to catheter removal after 100 cases in RALP patients.
Pathological findings of the specimens (Table 5) showed a difference in the positive surgical margin rates between the groups (17% in RALP vs 23% in RRP). This can be attributed to the superior visualisation of the robotic system, resulting in minor trauma to the prostatic capsule. Di Pierro et al. described PSM rates of 16% with RALP group, and 32% with RRP group, Tewari et al. 9% in RALP vs 23% in RRP and Parsons et al. reported no significant difference in PSM rate between the two groups.
There was a significant difference in 12-month continence rates favouring the RALP group. This is consistent with the findings of numerous studies in the literature. [25, 26]We performed reconstruction of the posterior part of the rhadosphincter, described by Rocco et al., preservation of maximal urethral length by careful apical dissection  and water-tight urethrovesical anastomosis. .
Our study is similar to that published by Şimşir et al. who compared 204 RARPs and 755 RRPs from 2007 and 2019.  In their study, the operation time was shorter in the open group (117 vs 188 min), and estimated blood loss (328 vs 150 ml), blood transfusion rate (12 vs 2), and re-operation rate (6 vs 0) were in favour of the robotic group. Mean length of hospital stay, urine leak rate, complication rate and the 12th-month continence rate were better in the robotic group.
Chen et al. who reported 500 RALP cases by one surgeon and analyzed factors affecting functional and oncological outcomes. They reported BCR PSA, postoperative Gleason score and pathological T staging as independent risk factors for BCR . In another study by Asimakopoulos et al. , 1627 patients underwent RALP from 2005 to 2010. RFS at 12, 24, 48 and 60 months after RALP were 94.6%, 91.2%, 79.3% and 73.1%, respectively. PSA, pathologic Gleason score, pathological T staging and PSM were significant independent predictors of RFS. This is in concordance with our study.
Although the survival curves of two cohorts in our study were not comparable, the OS at 84 months is similar in both groups (87.3% in RALP vs 83.2% in RRP). This reflects on little or no change in overall survival of patients undergoing radical prostatectomy, despite difference in the time periods and type of surgery.
The study's primary limitation is that it is a prospective case comparison with retrospective cohorts. The cohort is from a different decade where the investigative modalities were not comparable. Although the surgeon is the same, the surgeon's abilities in robotic and open surgeries may be different. Lastly, we could not assess the erectile function of the RALP patients consistently, which could not be incorporated in our study.