In this study, SRP showed comparable peri-operative and short-term results compared to DRP in surgical complications, continence rate, positive margin rate, and 3-month postoperative undetectable PSA level rate. The sRP even outperformed the idRP in terms of BL and OT. Our preliminary results showed that robotic assisted prostatectomy using the Senhance robotic system is safe and feasible.
The Senhance robotic system is a laparoscopy-based platform with tactile feedback. For a laparoscopic surgeon, it is straightforward, easy to adopt, and has a short learning curve [12]. In addition, the three-dimensional view with 5x image magnification and the stability of the robotic arms help the surgeon to perform RP efficiently [13]. Hence, the peri-operative outcomes, including OT, BL, early complication rate, and 3-month postoperative incontinence rate, were comparable to those of DRP. However, the da Vinci robotic system has seven degrees of freedom for its robotic arms. This feature is highly useful for the reconstructive steps, such as vesicourethral anastomosis. The vesicoureteral anastomosis time was much longer for SRP than for DRP. Nonetheless, the shorter docking time (5 minutes) offset the longer anastomosis time. Furthermore, only 7 patients needed Foley catheter indwelling for more than 6 days, which suggests that the anastomoses performed with the Senhance robotic system are secure. Compared to the iDRP, the sRP had shorter OT, less BL, and lower postoperative 3-month incontinence rate. A greater understanding of the prostate anatomy and improvements in surgical technique improvement during the recent 10 years may account for the better outcomes.
The other merit of the Sehance robotic system is its tactile feedback. The da Vinci robotic system has been shown to have superior visualization that could compensate for its lack of tactile feedback, especially for experienced surgeons [14]. Tactile feedback has been shown to result in less tissue injury in in vivo animal model experiments [15]. In our limited experience, the tactile feedback may help with bladder neck identification and dissection and may also prevent overstretching of the neurovascular bundle during dissection. However, the surgical flow of the operation may be disrupted due to a built-in pause of the arm movements whenever the tactile system issues a warning for “exceeding the force limit”.
Regarding the oncological outcomes, there was no difference in the positive surgical margin rate or 3-month postoperative undetectable PSA level rate between SRP and DRP. Whether they had similar biochemical recurrence rates needs a longer follow-up time. When doing never-sparing procedures, surgeons may use scissors to peel off the neurovascular bundle from the prostate using the da Vinci robotic system. With the Senhance robotic system, due to a lack of 7-degree endo wrists and limitations from the tactile feedback, we use scissors to instead cut off the neurovascular bundle from the prostate. This maneuver increases the iatrogenic damage during manipulation of the prostate and may lead to incomplete preservation of the neurovascular bundle. Whether it would affect potency and biochemical recurrence rates need further research.
There have been two studies that reported on Senhance robotic prostatectomy results and peri-operative outcomes. [8, 11] Compared to those two studies, our cohorts reported similar rates of major complications, defined as Clavian-Dindo classification ≥ 3, which ranged from 0–3%. The positive surgical margin rate was also comparable; Kastelan et al. reported 27.5% and Venckus et al. reported 33.9%. Lymphadenectomy was also performed laparoscopically in these two series without robotic assistance similar to our cohort. This may be due to the limitations that Senhance robotic arms have in reaching the more lateral parts of the lower abdomen and the pelvis. Our median OT (231 mins) was longer than the median OT of the previously reported cohorts (Venckus et al. 180 minutes and Kastelan et al. 200 minutes), which may be attributed to the difference in surgeon experiences and the rate of lymphadenectomy. The surgeon in their series were all experienced LRP surgeons and rate of lymphadenectomy was only 10–20% in their series as opposed to routine lymphadenectomy in our series.
The OT curves for the LRP experienced surgeon (more than 100 cases of LRP and DRP experience) and the LRP naive surgeons both showed downward trends, but the slope was steeper for the LRP experienced surgeon. This result indicates that the SRP is easily learned for laparoscopic experienced surgeons. The LRP experienced surgeon only needed several cases to familiarize themselves with the system and could benefit from its merits quickly. The disadvantage of this system is that the robotics arms occupy more space, such that only three robotic arms can be use in the limited space of our operation room.
The major advantage of Senhance robotic system is its lower cost. The re-sterilizable instruments reduce the high medical expenses of robotic surgery. The higher cost of robotic surgery is a major barrier to its widespread adoption. In our study, the total cost of SRP was almost half the cost of DRP. This is especially important for patients visiting community hospitals or impoverished patients. A recent study comparing the cost of da Vinci hysterectomy and Senhance hysterectomy reported a total cost of Senhance hysterectomy at $559, which was much lower than the cost of da Vinci hysterectomy at $1,393 [16]. SRP provides an affordable choice for RP.
There were several limitations to our study. First, our results may be biased by the small sample size and the heterogeneity in the preoperative and oncologic characteristics of our patients. Preoperative stage and prostatectomy pathologic reports showed that the sRP had a higher Gleason score and more T3b and T4 stages. This may reflect the poor health awareness and lower social economic status of the patients visiting the NTUH Yunlin Branch, a community hospital, as opposed to the patients visiting a tertiary medical center. Second, the data collection in these three cohort did not follow the same protocol; however we only collected the objective data which were not easily biased by the collection process. Third, the cost analysis may not be applicable to other countries with different medical insurance systems. Fourth, the analysis of the oncologic outcomes, such as biochemical recurrence, needs a longer follow-up period. In addition, long-term functional outcomes, such as urinary incontinence and erectile dysfunction, need to be obtained. Still, this is the first study to compare SRP with DRP. We showed comparable outcome in safety and feasibility of the Senhance robotic system to the da Vinci system in RP.