When Partial Nephrectomy is Unsuccessful: Understanding the Reasons for Conversion from Robotic Partial to Radical Nephrectomy at a Tertiary Referral Center

Partial or radical nephrectomy for complex renal mass: a comparative analysis of oncological outcomes and complications from the ROSULA (Robotic Surgery for Large Renal Mass) Collaborative Group

PURPOSE

To compare outcomes of robotic-assisted partial nephrectomy (RAPN) and minimally invasive radical nephrectomy (MIS-RN) for complex renal masses (CRM).

METHODS

We conducted a retrospective multicenter analysis of CRM patients who underwent MIS-RN and RAPN. CRM was defined as RENAL score 10-12. Primary outcome was overall survival (OS). Secondary outcomes were cancer-specific survival (CSS), recurrence, and complications. Multivariable analysis (MVA) and Kaplan-Meier Analysis (KMA) were used to analyze functional and survival outcomes for RN vs. PN by pathological stage.

RESULTS

926 patients were analyzed (MIS-RN = 437/RAPN = 489; median follow-up 24.0 months). MVA demonstrated lack of transfusion (HR = 1.63, p = 0.005), low-grade (HR = 1.18, p = 0.018) and smaller tumor size (HR = 1.05, p < 0.001) were associated with OS. Younger age (HR = 1.01, p = 0.017), high-grade (HR = 1.18, p = 0.017), smaller tumor size (HR = 1.05, p < 0.001), and lack of transfusion (HR = 1.39, p = 0.038) were associated with CSS. Increasing tumor size (HR = 1.18, p < 0.001), high-grade (HR = 3.21, p < 0.001), and increasing age (HR = 1.02, p = 0.009) were independent risk factors for recurrence. Type of surgery was not associated with major complications (p = 0.094). For KMA of MIS-RN vs. RAPN for pT1, pT2 and pT3, 5-year OS was 85% vs. 88% (p = 0.078); 82% vs. 80% (p = 0.442) and 84% vs. 83% (p = 0.863), respectively. 5-year CSS was 98% for both procedures (p = 0.473); 94% vs. 92% (p = 0.735) and 91% vs. 90% (p = 0.581). 5-year non-CSS was 87% vs. 93% (p = 0.107); 87% for pT2 (p = 0.485) and 92% for pT3 for both procedures (p = 0.403).

CONCLUSION

RAPN in CRM is not associated with increased risk of complications or worsened oncological outcomes when compared to MIS-RN and may be preferred when clinically indicated.

3D renal model for surgical planning of partial nephrectomy: A way to improve surgical outcomes

OBJECTIVE

to evaluate the impact of 3D model for a comprehensive assessment of surgical planning and quality of partial nephrectomy (PN).

MATERIALS AND METHODS

195 patients with cT1-T2 renal mass scheduled for PN were enrolled in two groups: Study Group (n= 100), including patients referred to PN with revision of both 2D computed tomography (CT) imaging and 3D model; Control group (n= 95), including patients referred to PN with revision of 2D CT imaging. Overall, 20 individuals were switched to radical nephrectomy (RN). The primary outcome was the impact of 3D models-based surgical planning on Trifecta achievement (defined as the contemporary absence of positive surgical margin, major complications and ≤30% postoperative eGFR reduction). The secondary outcome was the impact of 3D models on surgical planning of PN. Multivariate logistic regressions were used to identify predictors of selective clamping and Trifecta's achievement in patients treated with PN (n=175).

RESULTS

Overall, 73 (80.2%) patients in Study group and 53 (63.1%) patients in Control group achieved the Trifecta (p=0.01). The preoperative plan of arterial clamping was recorded as clampless, main artery and selective in 22 (24.2%), 22 (24.2%) and 47 (51.6%) cases in Study group vs. 31 (36.9%), 46 (54.8%) and 7 (8.3%) cases in Control group, respectively (p<0.001). At multivariate logistic regressions, the use of 3D model was found to be independent predictor of both selective or super-selective clamping and Trifecta's achievement.

CONCLUSION

3D-guided approach to PN increase the adoption of selective clamping and better predict the achievement of Trifecta.

Factors Affecting Robotic Partial Nephrectomy Conversion to Radical Nephrectomy: A Retrospective Multi-Institutional Analysis in the Michigan Urologic Surgery Improvement Collaborative (MUSIC)

OBJECTIVE

To identify factors related to the conversion of robot-assisted partial nephrectomy (RPN) to robot-assisted radical nephrectomy (RRN) based on data collected by a statewide database in Michigan.

METHODS

Using the Michigan Urological Surgery Improvement Collaborative-Kidney mass: Identifying and Defining Necessary Evaluation and therapY (MUSIC-KIDNEY) database we identified 574 patients for whom RPN was planned. Patient and tumor characteristics were obtained including body mass index (BMI), Charlson comorbidity index (CCI), RENAL nephrometry score, tumor size, and pathologic staging. Treating centers were subdivided by annualized case volume and academic status. Bivariate and multivariate analyses were performed to assess the impact of these factors on the risk of conversion to RRN from RPN.

RESULTS

The conversion rate of RPN to RN was 5.75% (33/574). The difference in RENAL nephrometry score, tumor stage, and size reached statistical significance on bivariate analysis (p<0.001). The tumor stage also reached statistical significance on multivariate analysis [odds ratio (OR); 95%CI (8.97; 3.93-20.48) p<0.001]. The conversion rate was lower among high-volume versus low-volume practices; however, statistical significance was not reached [5.2% (27/520) vs.11% (6/54); p=0.11].

CONCLUSIONS

 Patient factors such as tumor size and renal nephrometry score are likely related to the conversion of RPN to RRN decisions. The data shows that Michigan urologists appear to appropriately assess intra-operative findings and convert to RRN in cases of more advanced kidney tumors. Lower volume centers appear to trend towards a higher conversion rate. Continued quality improvement tracking analysis may further clarify this relationship.

Partial Nephrectomy, a Comparison between Different Modalities: A Tertiary Care Center Experience

Kidney cancer, with 4% of all malignancies, is one of the most common malignancies occurring among in adults. In Saudi Arabia, kidney cancer comprises 2.3% of all cancers, and its incidence has increased by 33%. Partial nephrectomy (PN) is considered as the gold standard for T1 renal masses. In this retrospective study, we did a chart review for all patients who underwent PNs between April 2013 and February 2019. Data comprised presentation, tumor size, type of procedure (open vs. laparoscopic vs. robotic), and intra- and post-operative complications. Chi-square, ANOVA, and cross-tabulation were done using SPSS software. P > 0.05 was considered significant. Approval was obtained from the institutional review board of King Abdullah International Medical Research Center. In all, 69 patients were identified: 26 (37.7%) males and 43 (62.3%) females, with mean age = 54.53 ± 13.21 years; mean body mass index = 32.36 ± 7.03, and mean tumor size = 3.7 ± 1.72 cm. In terms of presentation, most patients (50, 72.4%) presented incidentally as opposed to symptomatic presentation. Of these patients, 18 (26.1%) underwent open partial nephrectomy (OPN), 29 (42%) laparoscopic partial nephrectomy (LPN), and 22 (31.9%) robotic partial nephrectomy (RPN). On comparing minimally invasive surgery (MIS) PN with OPN, we found that OPN had more blood loss and a longer hospital stay but a shorter operating room (OR) time. Results of PN irrespective of the procedure type, whether it was OPN, LPN, or RPN, were similar if performed by experienced surgeons. However, open procedures involved a higher blood loss, more operative time, and longer hospital stay when compared with minimally invasive techniques.

Application of IRIS Three-Dimensional Anatomical Models As Preoperative Surgical Planning Tools in the Management of Localized Renal Masses

Introduction: The use of volume-rendered images is gaining popularity in the surgical planning for complex procedures. IRIS™ is an interactive software that delivers three-dimensional (3D) virtual anatomical models. We aimed to evaluate the preoperative clinical utility of IRIS for patients with ≤T2 localized renal tumors who underwent either partial nephrectomy (PN) or radical nephrectomy (RN). Patients and Methods: Six urologists (four faculty and two trainees) reviewed CT scans of 40 cases over 2 study phases, using conventional two-dimensional (2D) CT alone (Phase-I), followed by the CT + IRIS 3D model (Phase-II). After each review, surgeons reported their decision on performing a PN or an RN and rated (Likert scale) their confidence in completing the procedure as well as how the imaging modality influenced specific procedural decisions. Modifications to the choice of procedure and confidence in decisions between both phases were compared for the same surgeon. Concordance between surgeons was also evaluated. Results: A total of 462 reviews were included in the analysis (231 in each phase). In 64% (95% CI: 58-70%) of reviews, surgeons reported that IRIS achieved a better spatial orientation, understanding of the anatomy, and offered additional information compared with 2D CT alone. IRIS impacted the planned procedure in 20% of the reviews (3.5% changed decision from PN to RN and 16.5% changed from RN to PN). In the remaining 80% of reviews, surgeons' confidence increased from 78% (95% CI: 72-84%) with 2D CT, to 87% (95% CI: 82-92%) with IRIS (p = 0.02); this confidence change was more pronounced in cases with a high RENAL score (p = 0.009). In 99% of the reviews, surgeons rated that the IRIS accurately represented the anatomical details of all kidney components. Conclusion: Application of IRIS 3D models could influence the surgical decision-making process and improve surgeons' confidence, especially for robot-assisted management of complex renal tumors.

The role of open radical nephrectomy in contemporary management of renal cell carcinoma

Radical nephrectomy (RN) remains a cornerstone of the management of localised renal cell carcinoma (RCC). RN involves the en bloc removal of the kidney along with perinephric fat enclosed within Gerota's fascia. Key principles of open RN include appropriate incision for adequate exposure, dissection and visualisation of the renal hilum, and early ligation of the renal artery and subsequently renal vein. Regional lymph node dissection (LND) facilitates local staging but its therapeutic role remains controversial. LND is recommended in patients with high risk clinically localised disease, but its benefit in low risk node-negative and clinically node-positive patients is unclear. Concomitant adrenalectomy should be reserved for patients with large tumours with radiographic evidence of adrenal involvement. Despite a recent downtrend in utilisation of open RN due to nephron-sparing and minimally invasive alternatives, there remains a vital role for open RN in the management of RCC in three domains. Firstly, open RN is important to the management of large, complex tumours which would be at high risk of complications if treated with partial nephrectomy (PN). Secondly, open RN plays a crucial role in cytoreductive nephrectomy (CN) for metastatic RCC, in which the laparoscopic approach achieves similar results but is associated with a high reoperation rate. Finally, open RN is the current standard of care in the management of inferior vena caval (IVC) tumour thrombus. Management of tumour thrombus requires a multidisciplinary approach and varies with cranial extent of thrombus. Higher level thrombus may require hepatic mobilisation and circulatory support, whilst the presence of bland thrombus may warrant post-operative filter insertion or ligation of the IVC.

Laparoscopic and Robotic-Assisted Partial Nephrectomy: An Overview of Hot Issues

Laparoscopic partial nephrectomy and robot-assisted partial nephrectomy are attracting increased attention from urologists. They can achieve the same effect of oncology control as radical nephrectomy; moreover, they can offer better preservation of renal function, thus obtaining long-term living benefits. The indications are also expanding, making it possible for larger and more difficult tumors. Laparoscopic partial nephrectomy and robot-assisted partial nephrectomy can be performed by transperitoneal and retroperitoneal approaches, with their individual advantages and limitations. In addition, the renal tumor scoring systems have been widely used and studied in laparoscopic partial nephrectomy and robot-assisted partial nephrectomy. In -order to better preserve renal function, the zero-ischemia technique is widely used. The application of intraoperative imaging technology provides convenience and greater benefits. Besides, whether minimal invasive partial nephrectomy can be performed without stop antiplatelet treatment is still disputed. Clinicians perform substantial exploration and practice to achieve the "trifecta" of surgery: complete resection of the tumor, maximum protection of renal function, and no complications.

Analyzing National Incidences and Predictors of Open Conversion During Minimally Invasive Partial Nephrectomy for cT1 Renal Masses

Objectives: To analyze predictors of open conversion during minimally invasive partial nephrectomy (MIPN) for cT1 renal masses. Methods: The National Cancer Database (NCDB) was investigated for kidney cancer patients who underwent partial nephrectomy (PN) between 2010 and 2015. Patients who underwent MIPN were stratified into converted and nonconverted groups. Sociodemographics, facility characteristics, and surgical outcomes were compared between the two groups, and multivariate logistic regression model was fitted to identify independent predictors of open conversion. Results: In total, 54,246 patients underwent PN for kidney cancer during the 6-year period. Of those, 18,994 (35%) were open partial nephrectomies (OPNs) and 35,252 (64%) were MIPN. Overall, 1010 (2.87%) of MIPNs were converted to OPN. There was an increasing utilization of MIPN from 50.35% in 2010 to 74.73% in 2015. Patients who had open conversion had more 30-day readmissions (5.95% vs 3.31%, p < 0.01). On multivariate analysis; high-volume facility (>30 MIPNs/year), year of surgery (2015 vs 2010), and robotic approach predicted a lower likelihood of conversion (odds ratio [OR] 0.52, confidence interval [CI] 0.44-0.62; OR 0.59, CI 0.47-0.73; and OR 0.31, CI 0.27-0.35; respectively, p < 0.001 for all). Conversely, Medicaid (vs private insurance; OR 1.75, CI 1.39-2.19, p < 0.001) and male sex (OR 1.26, CI 1.11-1.44, p < 0.001) were independent predictors of conversion. Conclusions: Open conversion in MIPN occurred in 2.87% of cases. There was an increasing utilization of MIPN associated with decreased conversion rates. Higher volume hospitals and progressing year of surgery were associated with less likelihood of conversion.

Predictive Value of Nephrometry Scores in Nephron-sparing Surgery: A Systematic Review and Meta-analysis

CONTEXT

Over the last decade, several nephrometry scores (NSs) have been introduced with the aim of facilitating preoperative decision making, planning, and counseling in the field of nephron-sparing surgery. However, their predictive role remains controversial.

OBJECTIVE

To describe currently available nephrometry scores and to determine their predictive role for different outcomes by performing a systematic review and meta-analysis of the literature.

EVIDENCE ACQUISITION

PubMed, Embase®, and Web of Science were screened to identify eligible studies. Identification and selection of the reports were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). A pooled analysis of NS predictive role of intraoperative, postoperative, oncological, and functional outcomes was performed. Odds ratio was considered the effect size. All the analyses were performed using Stata 15.0, and statistical significance was set at p≤ 0.05.

EVIDENCE SYNTHESIS

Overall, 51 studies meeting our inclusion criteria were identified and considered for the analysis. Except for one prospective randomized trial, all the studies were retrospective. All the studies were found to be of intermediate quality, except for one of high quality. Most studies assessed the predictive role of the Radius-Exophytic/Endophytic-Nearness-Anterior/Posterior-Location (RENAL) and Preoperative Aspects and Dimensions Used for an Anatomical (PADUA) scores, mostly regarding complications after nephron-sparing surgery. RENAL was an independent predictor of an on-clamp procedure (p< 0.001). Mayo Adhesive Probability score was related to adhesive perinephric fat (p= 0.005). Continuous and high-complexity RENAL scores were predictors of warm ischemia time (WIT; p= 0.006 and p< 0.001, respectively). Continuous (p< 0.001) and high-complexity (p< 0.001) PADUA scores were related to WIT. Continuous and high-complexity RENAL scores were predictors of overall complications (p= 0.002 and p< 0.001, respectively). PADUA score was related to complications both as continuous (p< 0.001) and as a categorical value (p< 0.002). The RENAL scores R=3 (p= 0.008), E=2 (p= 0.039), and hilar location (p= 0.006) were predictors of histological malignancy. Continuous and categorical RENAL scores were independent predictors of an estimated glomerular filtration rate (eGFR) increase (p= 0.006 and p< 0.001, respectively). The Diameter-Axial-Polar score (p= 0.018) and Peritumoral Artery Scoring System (PASS; p= 0.02) were also independent predictors.

CONCLUSIONS

The literature regarding nephrometry scoring systems is sparse, and mostly focused on RENAL and PADUA, which are easy to calculate and have a good correlation with most outcomes. Renal Pelvic Score is the best predictor of pelvicalyceal entry/repair and urine leak, whereas Surgical Approach Renal Ranking and PASS strongly predict surgical approach and renal function variation, respectively. Other nephrometry scores based on mathematical models are limited by their complexity, and they lack evidence supporting their predictive value.

PATIENT SUMMARY

We reviewed the medical literature regarding the use and value of so-called "nephrometry scores," which are scoring systems based on radiological imaging and made to grade the complexity of a renal tumor. We analyzed whether these scoring systems can predict some of the outcomes of patients undergoing surgical removal of renal tumors.

Are there limits of robotic partial nephrectomy? TRIFECTA outcomes of open and robotic partial nephrectomy for completely endophytic renal tumors

BACKGROUND

To compare the outcomes of robot-assisted (RAPN) and open partial nephrectomy (OPN) for completely endophytic renal tumors.

METHODS

Consecutive patients undergoing OPN or RAPN for entirely endophytic tumors in four high-volume centers between 2008 and 2016 were identified. Endophytic masses were identified based on sectional imaging. Patient characteristics and surgical outcome were compared using Mann-Whitney-U-test and chi-squared-tests. Uni- and multivariate analyses were performed to identify predictors of TRIFECTA achievement and excisional volume loss.

RESULTS

Out of 1128 patients, 10.9% (64) of RAPN and 13.9% (76) of OPN underwent surgery for entirely endophytic tumors. Operative time was longer for RAPN (169 vs 140 min, P = 0.03) while ischemia time was shorter (13 vs 18 min, P = 0.001). Complication rates were comparable (21% OPN vs 22% RAPN, P = 0.91) and TRIFECTA achievement was not different between the groups (68% OPN vs 75% RAPN, P = 0.39). In multivariate analyses type of surgery was not associated with TRIFECTA achievement or excisional volume loss. Here, only tumor complexity (OR 0.48, P = 0.001) and size (OR 1.01, P = 0.002) were independent predictors.

CONCLUSION

For entirely endophytic tumors, both RAPN and OPN offer good TRIFECTA achievement. This encourages the use of NSS even for these highly complex tumors using the surgeon's preferred approach.

Conversion of Robot-assisted Partial Nephrectomy to Radical Nephrectomy: A Prospective Multi-institutional Study

OBJECTIVE

To assess the incidence and factors affecting conversion from robot-assisted partial nephrectomy (RAPN) to radical nephrectomy.

METHODS

Between November 2014 and February 2017, 501 patients underwent attempted RAPN by 22 surgeons at 14 centers in 9 countries within the Vattikuti Collaborative Quality Initiative database. Patients were permanently logged for RAPN prior to surgery and were analyzed on an intention-to-treat basis. Multivariable logistic regression with backward stepwise selection of variables was done to assess the factors associated with conversion to radical nephrectomy.

RESULTS

Overall conversion rate was 25 of 501 (5%). Patients converted to radical nephrectomy were older (median age [interquartile range] 66.0 [61.0-74.0] vs 59.0 [50.0-68.0], P = .012), had higher body mass index (BMI) (median 32.8 [24.9-40.9] vs 27.8 [24.6-31.5] kg/m², P = .031), higher age-adjusted Charlson comorbidity score (median 6.0 [4.0-7.0] vs 4.0 [3.0-5.0], P <.001), higher American Society of Anesthesiologists score (score ≥3; 13/25 (52.0%) vs 130/476 (27.3%), P = .021), Preoperative estimated glomerular filtration rate (P = .141), clinical tumor stage (P = .145), tumor location (P = .140), multifocality (P = .483), and RENAL (radius, exophytic/endophytic properties, nearness of tumor to the collecting system or sinus in millimeters, and anterior/posterior location relative to polar lines) nephrometry score (P = .125) were not significantly different between the groups. On multivariable analysis, independent predictors for conversion were BMI (odds ratio [95% confidence interval]; 1.070 [1.018-1.124]; P = .007) and Charlson score (odds ratio [95% confidence interval]; 1.459 [1.179-1.806]; P = .001).

CONCLUSION

RAPN was associated with a low rate of conversion. Independent predictors of conversion were BMI and Charlson score. Tumor factors such as clinical stage, location, multifocality, or RENAL score were not associated with increased risk of conversion.

Association of Robotic-Assisted vs Laparoscopic Radical Nephrectomy With Perioperative Outcomes and Health Care Costs, 2003 to 2015

IMPORTANCE

Use of robotic surgery has increased in urological practice over the last decade. However, the use, outcomes, and costs of robotic nephrectomy are unknown.

OBJECTIVES

To examine the trend in use of robotic-assisted operations for radical nephrectomy in the United States and to compare the perioperative outcomes and costs with laparoscopic radical nephrectomy.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study used the Premier Healthcare database to evaluate outcomes of patients who had undergone robotic-assisted or laparoscopic radical nephrectomy for renal mass at 416 US hospitals between January 2003 and September 2015. Multivariable regression modeling was used to assess outcomes.

EXPOSURES

Robotic-assisted vs laparoscopic radical nephrectomy.

MAIN OUTCOMES AND MEASURES

The primary outcome of the study was the trend in use of robotic-assisted radical nephrectomy. The secondary outcomes were perioperative complications, based on the Clavien classification system, and defined as any complication (Clavien grades 1-5) or major complications (Clavien grades 3-5, for which grade 5 results in death); resource use (operating time, blood transfusion, length of hospital stay); and direct hospital cost.

RESULTS

Among 23 753 patients included in the study (mean age, 61.4 years; men, 13 792 [58.1%]), 18 573 underwent laparoscopic radical nephrectomy and 5180 underwent robotic-assisted radical nephrectomy. Use of robotic-assisted surgery increased from 1.5% (39 of 2676 radical nephrectomy procedures in 2003) to 27.0% (862 of 3194 radical nephrectomy procedures) in 2015 (P for trend <.001). In the weighted-adjusted analysis, there were no significant differences between robotic-assisted and laparoscopic radical nephrectomy in the incidence of any (Clavien grades 1-5) postoperative complications (adjusted rates, 22.2% vs 23.4%, difference, -1.2%; 95% CI, -5.4 to 3.0%) or major (Clavien grades 3-5) complications (adjusted rates, 3.5% vs 3.8%, difference, -0.3%; 95% CI, -1.0% to 0.5%). The rate of prolonged operating time (>4 hours) for patients undergoing the robotic-assisted procedure was higher than for patients receiving the laparoscopic procedure in the adjusted analysis (46.3% vs 25.8%; risk difference, 20.5%; 95% CI, 14.2% to 26.8%). Robotic-assisted radical nephrectomy was associated with higher mean 90-day direct hospital costs ($19 530 vs $16 851; difference, $2678; 95% CI, $838 to $4519), mainly accounted for operating room ($7217 vs $5378; difference, $1839; 95% CI, $1050 to $2628) and supply costs ($4876 vs $3891; difference, $985; 95% CI, $473 to $1498).

CONCLUSIONS AND RELEVANCE

Among patients undergoing radical nephrectomy for renal mass between 2003 and 2015, the use of robotic-assisted surgery increased substantially. The use of robotic-assistance was not associated with increased risk of any or major complications but was associated with prolonged operating time and higher hospital costs compared with laparoscopic surgery.

The incidence of unsuccessful partial nephrectomy within the United States: A nationwide population-based analysis from 2003 to 2015

PURPOSE

Partial nephrectomy (PN) remains underutilized within the United States and few reports have attempted to explain this trend. The aim of this study is to evaluate the nationwide incidence of unsuccessful PN and factors that predict its occurrence.

METHODS

Using the Premier Healthcare Database, we retrospectively analyzed a weighted sample of 66,432 patients undergoing curative surgery for renal mass between 2003 and 2015. PN intent was denoted by presence of insurance claims for the administration of mannitol. Unsuccessful PN was defined as an event in which patients were administered mannitol but received radical nephrectomy. A multivariate logistic regression model was generated to identify factors predicting unsuccessful PN.

RESULTS

Overall rates of unsuccessful PN declined from 33.5% to 14.5% since 2003. Conversion to radical nephrectomy occurred most frequently during laparoscopic (34.7%) and least frequently during robotic approach (13.6%). There was significant difference in the rate of unsuccessful PN between very high and very low volume surgeons (open: 39.4% vs. 13.3%, laparoscopic: 51.2% vs. 32.2%, and robot assisted: 27.1% vs. 9.4%, all P<0.001). After adjustment for patient- and hospital-related factors, surgical approach (laparoscopic vs. open, odds ratio = 1.74, 95% CI: 1.31-2.30, P<0.001) and annual surgeon volume (very high vs. very low, odds ratio = 0.27, 95% CI: 0.21-0.34 P<0.001) were associated with unsuccessful PN.

CONCLUSIONS

Although the rate of unsuccessful PN appears to be declining, it still remains common for low volume surgeons and with the laparoscopic surgical approach. Further evaluation of its effect on health care outcomes is necessary.