The number of cases required to overcome the “learning curve” and to reach “expert” status for RALP remains unclear. Related to this, a consensus definition of “expert” status is difficult given the complex nature of an operation that relies not only on surgical safety and oncologic cure, but also on long-term functional outcomes, including continence and potency. Previous investigators have reported that the number of cases required to overcome the “learning curve” for radical prostatectomy lies anywhere from 20 cases to 250 cases.14
The majority of these investigators have focused primarily on a decrease in operative times and positive surgical margins as evidence that the learning curve has been overcome. Furthermore, most of the data pertaining to safety, surgical margins, and long-term functional outcomes of RALP are from early adopters of the technology. The surgeons in these studies generally have extensive open, laparoscopic, or robotic experience.1–5
This underscores the current lack of baseline/benchmark data for RALP in the setting of new surgeons entering practice directly out of training.
Rosser et al6
reviewed records of 66 men who underwent RRP performed by 2 fellowship-trained surgeons in their first year of practice. Their reported positive margin rate was 14%, and one intraoperative rectal injury occurred. Three patients developed pulmonary embolism postoperatively, and 6 patients developed postoperative bladder neck contractures. They concluded that RRP positive margin rates of fellowship trained surgeons compared favorably with those in large series reported by more experienced surgeons. This study focused on positive margin rates at the expense of long-term oncologic and functional follow-up; our study aims to provide the same data with regard to RALP, while including 1-year oncologic and functional outcomes.
The safety profile in this series is comparable to those in the literature of experienced robotic surgeons. The overall complication rate was 16% in our series with a majority of those being Clavien grade 1 and 2 (minor). No reoperations, bladder neck contractures, or peri-operative deaths occurred. No rectal injuries or enterotomies occurred. One patient (1%) received a blood transfusion secondary to a postoperative epigastric bleed that resolved with conservative measures. One Clavien grade 4a complication (an intraoperative MI) occurred and was successfully treated with angioplasty and stent placement followed by anti-coagulation. This was the only patient who required ICU care. There was one Clavien grade 3 complication (pelvic hematoma causing pain) that required percutaneous drain placement. No wound complications (infections, hernias, or dehiscence) or symptomatic lymphoceles were noted. Two recent publications evaluated the complications of mature RALP series (2500 and 3317 patients).3,4
The most common peri-operative complication in each series was urine leakage. In our series, 82% of the patients were discharged home within 2 days of surgery and had no complications, with their catheter being removed within 14 days of surgery. Of patients in the series of 3317 patients, 90.2% noted the same.4
Surgeons learning RALP note the vesicourethral anastomosis to be one of the most difficult portions of the operation to master.7,15
Vesicourethral anastomosis takes longer for residents and fellows to gain proficiency with than any other portion of RALP.7
Experienced open surgeons incorporating RALP into practice have a higher rate of prolonged catheterization compared to fellowship-trained robotic surgeons.16
Twelve patients in this series (12%) had a catheter in place more than 14 days for various reasons including hematuria and anastomotic leak. In 4 patients, anastomotic leakage led to prolonged hospitalization (>2 days) and discharge to home with a drain in place. Of interest, 3 of the leaks requiring patients to go home with a drain in place occurred in the first 35 cases.
The overall positive margin rate in our experience was 21% with a 19% positive margin rate in those with pathologic T2 disease. RRP series have reported positive margins varying between 16% to 46%.17
RALP positive margin rates reported in the literature range anywhere from 3% to 35%.1,3,5,16
The common theme in most studies pertaining to prostate cancer margin positivity is that margins decrease with experience. Eight patients in our series had a detectable PSA within the 1-year follow-up period. Seven of these patients were ≥Gleason 7 on pathologic examination and 5 had positive surgical margins. Long-term follow-up is required to ensure a durable absence of PSA recurrence.
On direct questioning, 83.5% of patients required no pads at the 1-year follow-up period; 6.2% required one pad or more per day. These findings correlated with data of patients who answered EPIC question 27 at baseline and at the 1-year follow-up period. Pad-free continence of the highest volume robotic surgeon in the world is 96.3% at 12 months5
with mean age of patients in that series being younger (57.8 years vs 61.6 years) with a lower mean BMI (28.3 vs 31.4). These factors have previously been associated with improved continence following prostatectomy.18
At 1-year follow-up, 41% of patients who completed the HRQOL questionnaire reported sexual activity; 65% of patients failed to reach their preoperative erection status. Variability in the literature on assessing sexual function and the varying definitions of potency make analysis of erectile function following prostate cancer surgery difficult. Interestingly, 31% of patients in the series reported no sexual function before surgery. It remains to be seen if increasing surgical experience or the addition of more advanced surgical systems (Si surgical system, 4th robotic arm) will improve postoperative erection status. Regardless, we believe it is essential to provide patients with a clear understanding of the potential sexual side-effects following RALP.
A cofounding variable in this study is the incorporation of residents into the RALP of a fellowship-trained surgeon. Trainees were involved in 80% of the first 100 RALP. A chief resident assisted on 45 of the cases and performed various portions of the operation. For the first 100 cases, the chief resident did not perform any portion of the apical dissection or nerve sparing. The chief resident performed bladder neck dissection in 31 patients. None of these 31 operations accounted for the 2 patients with positive bladder neck margins on final pathology. Schroeck et al19
demonstrated that trainee involvement in RALP under the guidance of an experienced mentor does not affect margin positivity or EBL. It has been demonstrated that trainees also improve with experience with the most difficult portions of the operation to master being the anastomosis and the bladder neck dissection.7,19,20
Robotic surgical simulators may play a role in the near future in eliminating the initial awkwardness of trainees at the console, which can only improve trainee and patient safety during the operation.14
This study has several limitations. The outcomes of only 1 surgeon are reported. No assessment is provided of a control group of residents who completed training and entered practice without doing a subspecialty fellowship. Moreover, only 31% of patients had baseline and 1-year follow-up EPIC questionnaires completed leading to a possible response bias in the data. Since analysis of these data, we have altered our systems to improve acquisition of baseline and follow-up QOL data. Our definition of potency utilizing question 63 of EPIC also leaves open the possibility that a person who attempts intercourse 10 times in 1 month and is only successful once would be defined as “sexually active.” The first 100 cases were performed with the standard 3-arm da Vinci surgical robot. We now perform the procedure with a 4-arm Si surgical system. It is unknown whether the addition of the fourth arm to the surgery or the use of the more advanced Si system will alter surgical safety and outcomes. A future avenue of study would be pooled data from fellowship-trained robotic surgeons and those who only complete residency to assess for surgical safety, oncologic control, and long-term functional outcomes.
There remains no standardized credentialing system to evaluate surgeon competency and safety with regards to robotic surgery.21
Most medical malpractice claims surrounding robotic surgeries are secondary to systems malfunctions, and 75% of those arise intraoperatively.22
The most common cause of these intraoperative systems malfunctions are due to inexperience or lack of technical competence with the instrumentation/surgical device.21,22
The peri-operative safety profile provided in this study may suggest that fellowship training can advance the practice by cutting down on technical errors that may lead to costly malpractice claims for the physician and hospital.