|Year : 2020 | Volume
| Issue : 1 | Page : 23-26
Precision surgery using davinci robotic system for prostate cancer & its role in improving functional outcome
P Rajkumar, K Anil, Vishruth, C Tejus, N Srivatsa, SK Raghunath
Department of Urological Oncology and Robotic Surgery, HCG Cancer centre, Bengaluru, India
|Date of Web Publication||22-Oct-2020|
Dr. S K Raghunath
Department of Uro- Oncology and Robotic Surgery HCG Cancer Centre, Bengaluru
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Rajkumar P, Anil K, Vishruth, Tejus C, Srivatsa N, Raghunath S K. Precision surgery using davinci robotic system for prostate cancer & its role in improving functional outcome. J Precis Oncol 2020;1:23-6
|How to cite this URL:|
Rajkumar P, Anil K, Vishruth, Tejus C, Srivatsa N, Raghunath S K. Precision surgery using davinci robotic system for prostate cancer & its role in improving functional outcome. J Precis Oncol [serial online] 2020 [cited 2021 Mar 5];1:23-6. Available from: https://www.jprecisiononcology.com/text.asp?2020/1/1/23/298269
| Introduction|| |
The best way to cure cancer confined to prostate is total surgical removal. Radical prostatectomy (RP) is the only form of treatment for organ-confined disease that has been shown to reduce disease progression and disease specific mortality (1,2). The amount of research in last two decades of 20th century has made us better in understanding of surgical anatomy of prostate and its implication in radical surgery due to which open radical prostatectomy (ORP) had emerged as a gold standard treatment. Despite of all the knowledge, ORP is one of the most challenging surgeries in the field of urology. Early era of ORP witnessed higher mortality & post-operative morbidity, which gradually decreased with better understanding of anatomy and refinement of technique as described by Walsh et al(3). Introduction of daVinci robotic platform in early 21st century revolutionized the surgical technique and Robotic assisted radical prostatectomy (RARP) has become gold standard in the developed countries. We reviewed contemporary technical advancement & functional outcome measures of RARP in this article. The article mainly focuses on urinary continence & potency outcome after RARP.
| Outcome Goals of Rp|| |
Primary goal of any cancer surgery is a cancer control. However, it should be done in a manner that maximum function is preserved with best possible cancer control. Thus, three goals of RP in order of importance are cancer control, preservation of urinary control and preservation of sexual function so called “trifecta outcome” which has become the standard metrics (4). Since it's known that prostate cancer is relatively slow growing tumour, functional outcome is as equally important as oncological outcome from patient's perspective. In fact, functional outcome and not a primary treatment was associated with poor health related quality of life (HRQOL)(5) after prostate cancer treatment.
| Concept of “precision Surgery” & Davinci Robotic System|| |
The concept of precision surgery involves much more than a mastery of technical maneuvers. The definition of such precision is more sophisticated and involves a deeper understanding of the underlying biological foundation of disease that is then challenged with targeted, strategic interventions. Rather than treating many to benefit a few, precision surgery aims to apply surgical therapy to those most likely to benefit and to avoid surgery in those doomed to fail (6). After the advancement of “precision medicine” in prostate cancer, which included better diagnostic & prognostic approaches, contemporary prostate surgery has entered in the era of technologically driven “Precision surgery” tailored to combine maximal treatment efficacy with minimal impact on patient function and HRQOL (7).
To achieve the “trifecta outcome” with precision surgery, daVinci robotic system provides unique technical advantages. It provides excellent high definition, 3D vision with optical magnification up to 10x with options of 0 & 30 degree camera lens. This provides excellent view of precise anatomy in deep pelvis. The wrist like movement of instruments, truly described as “endowrist” results in easy maneuverability & precise steps without fatigue & tremors. The ease of intracorporeal suturing makes this technology far superior than open or laparoscopic technique. Along with a full control of instruments & camera, robotic surgeon has a distinct advantage of best possible ergonomics. Additional advantage of training console & interactive Video monitor provides a unique opportunity to train next generation as well. In a nutshell, this technology is supposed to help surgeon to preserve key anatomical structures for urinary continence and potency and thus improving peri-operative functional outcomes.
| Urinary Continence Recovery After Rarp|| |
The natural history of urinary function recovery after RP is such that most patients regain urinary continence within the first year; however, modest improvement in urinary continence can still be observed through the second year. Considering studies using no pad or safety pad as the continence definition, 12-month urinary incontinence rates ranged from 8% to 11%, with a mean value of 9% in a systemic review (8).
The continence recovery after RARP is multifactorial. Biological factors that negatively impact continence includes age, prior Lower urinary tract symptoms, prior TURP, functional bladder disorders, prostate size & body mass index, while only factor that positively impact continence is intra-abdominal membranous urethral length. About surgical factors, extensive apical dissection, damage to the neurovascular bundle (NVB), fibrosis, use of excessive thermal energy & traction of NVB can negatively impact continence while bladder neck sparing, anterior fixation & posterior reconstruction (Rocco stitch) can positively impact early recovery of continence (9).
Understanding of pathophysiology of post-prostatectomy incontinence (PPI) has ensured few modifications of surgical techniques with guarded benefits. Bladder neck sparing procedure preserves internal sphincter complex, which is responsible for passive continence. Study by Stolzenberg et al (10) reported that continence rate was improved at the time of catheter removal & at 3 months after bladder neck preservation versus without preservation. The supporting structures of the male urethra can be divided into the anterior and posterior support structures and the pelvic floor. A prospective randomized multicenter trial (11) supports the benefit of anterior retro pubic suspension and posterior reconstruction of urethral support for early recovery in continence. This technique also prevents urethral stump regression and relieves tension on anastomosis. Excessive fibrosis near urethro-vesical anastomosis can lead to poor continence rates due to compromise in function of external sphincter (12). Technical modification in form of precise & athermal apical dissection can be crucial to prevent fibrosis. Excellent 3D vision and magnification provided by robotic system makes it possible in majority of the cases. Strasser and Bartsch (13) found that the NVB directly innervates the membranous urethra. This would mean that damage to the NVB does affect the continence mechanism and preservation does lead to at least earlier recovery of continence after RP. This findings were supported by study conducted by Kaye et al (14). The study concluded that completely sparing at least 1 NVB (Unilateral preservation) along with its supportive tissues has a dramatic effect on the recovery of urinary continence and quality of life in preoperatively potent men.
| Erectile Function Recovery After Rarp|| |
Despite controversies regarding screening program for prostate cancer, it is an undisputed fact that increasing percentage of young men are being diagnosed with early prostate cancer. This, in turn, has led to an increase in the number of young candidates for RP with the expectation of curing cancer and minimizing the risk of urinary incontinence and erectile dysfunction.
The available literature shows fairly good recovery in erectile function after RARP. A systemic review(15) shows the mean values of the 3-, 6-, 12-, and 24-mo potency recovery rates are 50% (32–68%), 65% (50–86%), 70% (54–90%), and 79% (63–94%), respectively after RARP. As like continence, erectile function recovery is also multifactorial. These factors include patient characteristics (age, baseline erectile function, co-morbidities), surgical technique (non-versus uni- or bi-lateral nerve sparing; extrafascial versus inter- or intrafascial), and surgeon factors (surgical volume and skills) (16). Since the quality and quantity of nerve sparing (NS) during RARP determines potency outcomes, it is hypothesized that robotic technology positively impacts potency outcomes.
There is no doubt that unparalleled vision, magnification & maneuverability provided by robotic technology has provided us more precise anatomical details of NVBs. Continuous quest to improve potency rates has progressively developed better NS techniques. However it is to be understood that, NS & potency recovery rate should not cost poor oncological outcomes in form of higher positive surgical margins (PSM). As anatomical knowledge has increased, there has been a shift from the simplistic dichotomy “non-nerve sparing versus nerve sparing” or “intra-inter-extra-fascial” towards the concept of “incremental nerve sparing” or “incremental safety margin”(17). Tewari et al. proposed four grades of dissection by using the veins on the lateral aspect of the prostate as a vascular landmark(18). Pre-operative risk stratification was done to guide the NS grade. They concluded that Patients with greater degrees of NS had higher rates of intercourse and return to baseline sexual function without an increase in PSM rates. Patel and coworkers (19) proposed an inverse (grade 5 optimal NS, grade 1 no NS) five grade scale by using the arterial periprostatic vasculature as landmark and by identifying a “landmark” artery & concluded that the visual cues will help surgeons achieve more consistent NS during RARP. Kowalczyk et al. investigated the potential role of countertraction during the nerve-sparing dissection and concluded that reliance on countertraction to facilitate dissecting NVB away from the prostate leads to neuropraxia and delayed recovery of sexual function and potency. Subtle technical modification to dissect the prostate away from the NVB without countertraction enables earlier return of sexual function and potency (20). The concept that cautery-free dissection or pinpointed low-energy cauterization should be implemented when aiming at nerve preservation is well established. The role of thermal injury in NS & its negative impact for potency outcomes is also well established (15) & it should be aimed to use minimal or no thermal energy during dissection near apex, near seminal vesicle and so called lateral pedicles which will ensure better potency outcomes. Early result of Retzius sparing RARP has also showed promising result for better potency outcomes (21). The benefit of intraoperative neurovascular structure-adjacent frozen section examination (NeuroSAFE technique) of the prostate was demonstrated in open radical prostatectomy. Surgeons at Martini clinic, Germany described a safe and effective way of performing NeuroSAFE technique during RARP . In one of the study  by Patel et al. the placement of dehydrated human amnion/chorion membrane around the NVB can translate into earlier return of potency.
| Does Rarp Have Advantage of Better Functional Outcome over Open or Laparoscopic Approach?|| |
A systemic review and meta-analysis by Ficarra et al (19) showed a statistically significant advantage of RARP over open or laparoscopic approach in gaining better 12 month continence rates. Similarly, a systemic review and meta-analysis by same author group (15) showed first time, the significant advantage of 12 month potency rates of RARP over open surgery. One of the recent randomized control trial comparing RARP vs open surgery showed no difference in functional outcome at 12 weeks. However on closer look, The two surgeons involved in the trial had a very different surgical experience as one had performed about 200 robotic cases (in 2 years) and the other over 1500 open cases (in 15 years) at the start of the trial. Thus it can be argued that robotic surgery allowed less experience surgeon to achieve equal outcomes significantly faster. It has enlightened us with completely new aspect of robotic surgery.
| Conclusion|| |
Robotic surgery for prostate cancer by daVinci robotic surgery has clear advantage of achieving goal of functional outcome of RP by “Precision surgery” concept described earlier in the article. However, one must understand that technologically driven “Precision surgery” is only one important aspect of cancer care. The basic pillars of cancer care, understanding of biology and proper patient selection will always stand strong.
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