Shahab Hillyer

Functional Recovery After Partial Nephrectomy: Effects of Volume Loss and Ischemic Injury

PURPOSE We used what is to our knowledge a new method to estimate volume loss after partial nephrectomy to assess the relative contributions of ischemic injury and volume loss on functional outcomes. MATERIALS AND METHODS We analyzed the records of 301 consecutive patients who underwent conventional partial nephrectomy between 2007 and 2010 with available data to meet inclusion criteria. Percent functional volume preservation was measured at a median of 1.4 years after surgery. Modification of diet in renal disease-2 estimated glomerular filtration rate was measured preoperatively and perioperatively, and a median of 1.2 years postoperatively. Statistical analysis was done to study associations. RESULTS Hypothermia or warm ischemia 25 minutes or less was applied in 75% of cases. Median percent functional volume preservation was 91% (range 38%-107%). Percent glomerular filtration rate preservation at nadir and late time points was 77% and 90% of preoperative glomerular filtration rate, respectively. On multivariate analysis percent functional volume preservation and warm ischemia time were associated with nadir glomerular filtration rate while only percent functional volume preservation was associated with late glomerular filtration rate (each p <0.001). Late percent glomerular filtration rate preservation and percent functional volume preservation were directly associated (p <0.001). Recovery of function to 90% or greater of percent functional volume preservation predicted levels was observed in 86% of patients. In patients with de novo postoperative stage 3 or greater chronic kidney disease, percent functional volume preservation and Charlson score were associated with late percent glomerular filtration rate preservation. Warm ischemia time was not associated with late functional glomerular filtration rate decreases in patients considered high risk for ischemic injury. CONCLUSIONS In this cohort volume loss and not ischemia time was the primary determinant of ultimate renal function after partial nephrectomy. Technical modifications aimed at minimizing volume loss during partial nephrectomy while still achieving negative margins may result in improved functional outcomes.

Comparative Outcomes and Assessment of Trifecta in 500 Robotic and Laparoscopic Partial Nephrectomy Cases: A Single Surgeon Experience

PURPOSE We report a comparative analysis of a large series of laparoscopic and robotic partial nephrectomies performed by a high volume single surgeon at a tertiary care institution. MATERIALS AND METHODS We retrospectively reviewed the medical charts of 500 patients treated with minimally invasive partial nephrectomy by a single surgeon between March 2002 and February 2012. Demographic and perioperative data were collected and statistically analyzed. R.E.N.A.L. (radius, exophytic/endophytic properties, nearness of tumor to the collecting system or sinus in mm, anterior/posterior and location relative to polar lines) nephrometry score was used to score tumors. Those scored as moderate and high complexity were designated as complex. Trifecta was defined as a combination of warm ischemia time less than 25 minutes, negative surgical margins and no perioperative complications. RESULTS Two groups were identified, including 261 patients with robotic and 231 with laparoscopic partial nephrectomy. Demographics were similar in the groups. The robotic group was significantly more morbid (Charlson comorbidity index 3.75 vs 1.26), included more complex tumors (R.E.N.A.L. score 5.98 vs 7.2), and had lower operative (169.9 vs 191.7 minutes) and warm ischemia (17.9 vs 25.2 minutes) time, intraoperative (2.6% vs 5.6%, each p <0.001) and postoperative (24.53% vs 32.03%, p = 0.004) complications, and positive margin rate (2.9% vs 5.6%, p <0.001). Thus, a higher overall trifecta rate was observed for robotic partial nephrectomy (58.7% vs 31.6%, p <0.001). The laparoscopic group had longer followup (3.43 vs 1.51 years, p <0.001) and no significant difference in postoperative changes in renal function. Main study limitations were the retrospective nature, arbitrary definition of trifecta and shorter followup in the RPN group. CONCLUSIONS Our large comparative analysis shows that robotic partial nephrectomy offers a wider range of indications, better operative outcomes and lower perioperative morbidity than laparoscopic partial nephrectomy. Overall, the quest for trifecta seems to be better accomplished by robotic partial nephrectomy, which is likely to become the new standard for minimally invasive partial nephrectomy.

Perioperative Complications of Robot-assisted Partial Nephrectomy: Analysis of 886 Patients at 5 United States Centers

OBJECTIVE To review complications of robot-assisted partial nephrectomy (RAPN) at 5 centers, as classified by the Clavien system. MATERIALS AND METHODS A multi-institutional analysis of prospectively maintained databases assessed RAPN complications. From June 2007 to November 2011, 886 patients at 5 United States centers underwent RAPN. Patient demographics, perioperative outcomes, and complications data were collected. Complication severity was classified by Clavien grade. RESULTS Mean (standard deviation) data were patient age, 59.4 (11.4) years; age-adjusted Charlson Comorbidity Index, 3.0 (1.9); radiographic tumor size, 3.0 (1.6) cm; nephrometry score, 6.9 (2.0); and warm ischemia time, 18.8 (9.0) minutes. Median blood loss was 100 mL (interquartile range, 100-250 mL). Of the 886 patients, intraoperative complications occurred in 23 patients (2.6%) and 139 postoperative complications occurred in 115 patients (13.0%) for a total complication rate of 15.6%. Among the 139 postoperative complications, 43 (30.9%) were classified as Clavien 1, 64 (46.0%) were Clavien 2, 21 (15.1%) were Clavien 3, and 11 (7.9%) were Clavien 4. No complication-related deaths occurred. Intraoperative hemorrhage occurred in 9 patients (1.0%) and postoperative hemorrhage in 51 (5.8%). Forty-one patients (4.6%) required a perioperative blood transfusion, 10 (1.1%) required angioembolization, and 2 (0.2%) required surgical reexploration for postoperative hemorrhage. Urine leaks developed in 10 patients (1.1%): 3 (0.3%) required ureteral stenting, and 2 (0.2%) required percutaneous drainage. Acute postoperative renal insufficiency or renal failure developed in 7 patients (0.8%), 2 of whom required hemodialysis. The RENAL (radius, exophytic/endophytic properties of the tumor, nearness of tumor deepest portion to the collecting system or sinus, anterior/posterior descriptor and the location relative to polar lines) nephrometry scoring system accurately predicted RAPN complication rates. CONCLUSION Complication rates in this large multicenter series of RAPN appear to be acceptable and comparable with other nephron-sparing modalities. Most complications (77.0%) are Clavien 1 and 2 and can be managed conservatively.

Robotic Laparoendoscopic Single-Site Radical Nephrectomy: Surgical Technique and Comparative Outcomes

BACKGROUND Recent reports have suggested that robotic laparoendoscopic single-site surgery (R-LESS) is feasible, yet comparative studies to conventional laparoscopy are lacking. OBJECTIVE To report our early experience with R-LESS radical nephrectomy (RN). DESIGN, SETTING, AND PARTICIPANTS A retrospective review of R-LESS RN data was performed between May 2008 and November 2010. A total of 10 procedures were performed and subsequently matched to 10 conventional laparoscopic RN procedures (controls). The control group was matched with respect to patient age, body mass index (BMI), American Society of Anesthesiologists score, surgical indication, and tumor size. SURGICAL PROCEDURE R-LESS RN was performed using methods outlined in the manuscript and supplemental video material. All patients underwent R-LESS RN by a single surgeon. Single-port access was achieved via two commercially available multichannel ports, and robotic trocars were inserted either through separate fascial stabs or through the port, depending on the type used. The da Vinci S and da Vinci-Si Surgical Systems (Intuitive Surgical, Sunnyvale, CA, USA) with pediatric and standard instruments were used. MEASUREMENTS Preoperative, perioperative, pathologic, and functional outcomes data were analyzed. RESULTS AND LIMITATIONS The mean patient age was 64.0 yr of age for both groups, and BMI was 29.2 kg/m(2). There was no difference between R-LESS and conventional laparoscopy cases in median operative time, estimated blood loss, visual analogue scale, or complication rate. The R-LESS group had a lower median narcotic requirement during hospital admission (25.3 morphine equivalents vs 37.5 morphine equivalents; p=0.049) and a shorter length of stay (2.5 d vs 3.0 d; p=0.03). Study limitations include the small sample size, short follow-up period, and all the inherent biases introduced by a retrospective study design. CONCLUSIONS R-LESS RN offers comparable perioperative outcomes to conventional laparoscopic RN. Prospective comparison is needed to definitively establish the position of R-LESS in minimally invasive urologic surgery.

252 Robotic Partial Nephrectomies: Evolving Renorrhaphy Technique and Surgical Outcomes at a Single Institution

OBJECTIVE To describe the evolution of robotic partial nephrectomy (PN) technique and to analyze the surgical outcomes in a large single institution experience. MATERIALS AND METHODS Retrospective review of our institutional review board-approved, prospectively maintained, minimally invasive PN database yielded 252 robotic partial nephrectomy (RPN) procedures from June 2007 to October 2010. Our initial experience, adopted from our laparoscopic PN approach included a standard interrupted bolstered renorrhaphy, whereas our contemporary experience included a nonbolstered continuous horizontal mattress stitch for the capsular closure. Perioperative results were evaluated depending on renorrhaphy technique, length of warm ischemia time, and nephrometry scores. RESULTS Overall, mean tumor size was 3.1 ± 1.6 cm, operative time 190 ± 56 minutes, warm ischemia time 18.2 ± 9.4 minutes, and estimated blood loss 267 ± 275 mL. Significantly better outcomes were noted in the contemporary experience in terms of transfusion rate (8.2% vs 21.9%, P <.001), operative time (181 vs 219 minutes, P <.001), hospital stay (3.6 vs 4.3 days, P = .02), and complication rate (14.4% vs 33.8%, P <.01). Increasing tumor complexity based on RENAL score predicted longer operative time (P <.0001), warm ischemia time (P <.0001), and hospital stay (P <.04), and a greater risk of postoperative complications (P = .003). Of the series, only 2 patients had hemorrhagic complications (0.8%) requiring angioembolization, 4 patients developed urine leaks (1.5%), and 2 positive margins (0.8%) were noted. CONCLUSION We report the largest single-institution study with RPN to date. Despite it being a relatively nascent procedure, initial results suggest that RPN is an effective approach for minimally invasive nephron-sparing surgery. As experience is gained and the technique for RPN evolves, further improvement in outcomes will be noted.

Robotic Partial Nephrectomy Versus Laparoscopic Cryoablation for the Small Renal Mass

BACKGROUND Open partial nephrectomy (OPN) remains the gold standard for treatment of small renal masses (SRMs). Laparoscopic cryoablation (LCA) has provided encouraging outcomes. Robotic partial nephrectomy (RPN) represents a new promising option but is still under evaluation. OBJECTIVE Compare the outcomes of RPN and LCA in the treatment of patients with SRMs. DESIGN, SETTING, AND PARTICIPANTS We retrospectively analyzed the medical charts of patients with SRMs (≤4cm) who underwent minimally invasive nephron-sparing surgery (RPN or LCA) in our institution from January 1998 to December 2010. INTERVENTION RPN and LCA. MEASUREMENTS Perioperative complications and functional and oncologic outcomes were analyzed. RESULTS AND LIMITATIONS A total of 446 SRMs were identified in 436 patients (RPN, n=210; LCA, n=226). Patients undergoing RPN were younger (p<0.0001), had a lower American Society of Anesthesiologists score (p<0.001), and higher baseline preoperative estimated glomerular filtration rate (eGFR) (p<0.0001). Mean tumor size was smaller in the LCA group (2.2 vs 2.4cm; p=0.004). RPN was associated with longer operative time (180 vs 165min; p=0.01), increased estimated blood loss (200 vs 75ml; p<0.0001), longer hospital stay (72 vs 48h; p<0.0001), and higher morbidity rate (20% vs 12%, p=0.015). Mean follow-ups for RPN and LCA were 4.8 mo and 44.5 mo, respectively (p<0.0001). Local recurrence rates for RPN and LCA were 0% and 11%, respectively (p<0.0001). Mean eGFR decrease after RPN and LCA was insignificant at 1 mo, at 6 mo after surgery, and during last follow-up. Limitations include retrospective study design, length of follow-up, and selection bias. CONCLUSIONS Both techniques remain viable treatment options in the management of SRMs. A higher incidence of perioperative complications was found in patients undergoing RPN. However, the technique was not predictive of the occurrence of postoperative complications. Early oncologic outcomes are promising for RPN, which also seems to be associated with better preservation of renal function. Long-term follow-up and well-designed prospective comparative studies are awaited to corroborate these findings.

Diameter-Axial-Polar Nephrometry: Integration and Optimization of R.E.N.A.L. and Centrality Index Scoring Systems

PURPOSE The R.E.N.A.L. (radius, exophytic/endophytic properties, nearness of tumor to collecting system or sinus, anterior/posterior) and centrality index nephrometry scores enable systematic, objective assessment of anatomical tumor features. We systematically compared these systems using item analysis test theory to optimize scoring methodology. MATERIALS AND METHODS Analysis was based on 299 patients who underwent partial nephrectomy from 2007 to 2011 and met study inclusion criteria. Percent functional volume preservation, and R.E.N.A.L. and centrality index scores were measured. Late percent glomerular filtration rate preservation was calculated as the ratio of the late to the preoperative rate. Interobserver variability analysis was done to assess measurement error. All data were statistically analyzed. RESULTS A novel scoring method termed DAP (diameter-axial-polar) nephrometry was devised using a data based approach. Mean R.E.N.A.L., centrality index and DAP scores for the cohort were 7.3, 2.5 and 6 with 84%, 90% and 95% interobserver agreement, respectively. The DAP sum score and all individual DAP scoring components were associated with the clinical outcome, including percent functional volume preservation, warm ischemia time and operative blood loss. DAP scoring criteria allowed for the normalization of score distributions and increased discriminatory power. DAP scores showed strong linear associations with percent functional volume preservation (r(2) = 0.97) and late percent glomerular filtration rate preservation (r(2) = 0.81). Each 1 unit change in DAP score equated to an average 4% change in kidney volume. CONCLUSIONS DAP nephrometry integrates the optimized attributes of the R.E.N.A.L. and centrality index scoring systems. DAP scoring was associated with simplified methodology, decreased measurement error, improved performance characteristics, improved interpretability and a clear association with volume loss and late function after partial nephrectomy.

Nephrometry Score is Associated with Volume Loss and Functional Recovery After Partial Nephrectomy

PURPOSE Functional volume preservation after partial nephrectomy is a primary determinant of kidney function. We identified tumor features, including R.E.N.A.L. (radius for tumor size as maximal diameter, exophytic/endophytic tumor properties, nearness of deepest portion of tumor to collecting system or sinus, anterior/posterior descriptor and location relative to polar line) and centrality index nephrometry scores, associated with volume loss after partial nephrectomy. MATERIALS AND METHODS A chart and imaging review was done for 237 patients who underwent partial nephrectomy from 2007 to 2010 and met study inclusion criteria. R.E.N.A.L. and centrality index nephrometry scores were measured in all patients. Percent functional volume preservation was estimated a median of 1.4 years after surgery using the cylindrical volume ratio method. Statistical analysis was done to study associations. RESULTS Independent tumor features associated with percent functional volume preservation included tumor diameter (p < 0.001) and the distance from tumor periphery to kidney center (p = 0.02). R.E.N.A.L. and centrality index scores were associated with percent functional volume preservation (each p < 0.001). Nephrometry scores were also associated with nadir and late percent glomerular filtration rate preservation. Tumors classified as highly complex, with a centrality index score of 1.5 or less and a R.E.N.A.L. score of 10 or greater, were associated with an average 28% to 30% functional parenchymal volume loss of operated kidneys. A mean 8% difference in percent functional volume preservation was observed among low, intermediate and high tumor complexity categories for R.E.N.A.L. and centrality index scores. CONCLUSIONS R.E.N.A.L. and centrality index nephrometry scores were associated with changes in the percent functional volume preservation and the perioperative functional decrease. Nephrometry scores performed better than diameter alone on statistical analysis. Nephrometry scores may be useful to estimate the likelihood of operative volume loss and by proxy the functional outcome.

SPIDER Surgical System for Urologic Procedures With Laparoendoscopic Single-Site Surgery: From Initial Laboratory Experience to First Clinical Application

This case study describes our initial laboratory experience using the SPIDER surgical system (TransEnterix, Morrisville, NC, USA) for laparoendoscopic single-site surgery (LESS) urologic procedures and reports its first clinical application. The SPIDER system was tested in a laboratory setting and used for a clinical case of renal cyst decortication. Three tasks were performed during the dry lab session, and different urologic procedures were conducted in a porcine model. The time to complete the tasks and penalties were registered during the dry lab session. Perioperative outcomes and subjective assessment by the surgeons were registered. The surgeons had a positive experience with the SPIDER system, with a mean overall score of 3.6 (on a scale of 1-5). The surgeons were able to gain proficiency in performing tasks regardless of their level of expertise. The highest scores recorded were for ease of device insertion, instrument insertion and exchange, and triangulation. The lowest scores were for retraction. During the clinical case, the platform provided good triangulation without instrument clashing. However, retraction was challenging because of the lack of strength and precise maneuverability with the tip of the instruments fully deployed. The SPIDER system offers intuitive instrument maneuverability and restored triangulation without external instrument clashing. Further refinements are awaited to define its role in the urologic LESS armamentarium.

Robotic Laparoendoscopic Single Site Urological Surgery: Analysis of 50 Consecutive Cases

PURPOSE We present our cumulative experience with robotic laparoendoscopic single site urological surgery at a single institution. MATERIALS AND METHODS Medical records of patients undergoing robotic laparoendoscopic single site procedures between May 2008 and December 2010 were analyzed. The da Vinci® S or Si systems and 3 different multichannel single port devices were used. Demographic, intraoperative and postoperative data were assessed. RESULTS Overall, 50 patients were scheduled to undergo robotic laparoendoscopic single site urological surgery during the study period, representing 36% of the total patients undergoing laparoendoscopic single site surgery at our institution. Mean ± SD patient age was 60.2 ± 13.6 years. Mean body mass index was 27.0 ± 4.5 kg/m(2). Specifically, 24 patients underwent robotic laparoendoscopic single site renal surgery and the same method was used in 26 patients undergoing pelvic surgery. Mean operative time was 207 ± 74 minutes and mean estimated blood loss was 140 ± 111 ml. Four cases were converted to laparoscopy (2 standard, 2 robotic assisted) and 6 cases required at least 1 additional trocar outside of the single site incision. A rectal injury occurred during radical cystectomy, which was recognized intraoperatively and closed primarily without sequelae. Postoperative complications occurred in 8 cases and 1 was Clavien grade IV. Mean length of hospital stay was 2.9 ± 1.7 days. CONCLUSIONS Our preliminary experience with robotic laparoendoscopic single site surgery has demonstrated feasibility and safety in the realm of urological surgery. Widespread adoption of this new approach will likely require redesign of the robotic system or development of a task specific robotic platform, and should be limited to centers with significant robotic, laparoscopic and laparoendoscopic single site surgery experience.