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Urological Surgery

US03 - Factors and Outcomes Associated with Unplanned Conversion to Open in Nephrectomy

Introduction/Purpose: The incidence of renal cancer has nearly doubled over the last decade.1 Minimally-invasive surgery has developed into the gold standard for surgical interventions for renal cancers. A minimally-invasive approach is often preferred due to its many benefits when compared to open surgery, including decreased length of stay, decreased narcotic intake, faster return to normal activity, and preservation of oncologic standards.2,3 While both laparoscopic and robotic surgery have become standard approaches to surgical intervention for renal cancers, studies have found unplanned conversions to open surgery at rates of 4.9% and 6.0%, respectively.4 Unplanned conversions from a minimally invasive approach to an open approach have been associated with adverse patient outcomes, such as an increased risk of hospital readmission, mortality, and median length of stay.4,5 Minimal research has outlined potential risk factors for unplanned conversion to an open approach in nephrectomy. Identifying risk factors associated with unplanned conversion to open nephrectomy has clinical implications in reducing the occurrence of adverse postoperative outcomes resulting from conversion. In this study, we use the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database to examine factors associated with the unplanned conversion to open nephrectomy. We also aim to identify post-operative outcomes associated with this conversion

Methods or Case Description: A total of 14,186 patients were evaluated and 4,862 patients met the inclusion criteria of nephrectomy performed for kidney cancer. The data were then subcategorized into two groups: a planned minimally invasive surgery (MIS) only group (including laparoscopic, endoscopic, robotic and other MIS) (n=4,756), and unplanned conversion to an open robotic, laparoscopic, or endoscopic (n=106). Preoperative, intraoperative, and postoperative outcomes were compared between the planned MIS group and the unplanned conversion to open group. For continuous variables, the Wilcoxon-signed rank test was employed whereas Fisher’s exact test and Chi-squared analysis were utilized for categorical variables. Multivariate logistic regression was performed for the statistically significant variables in the basic statistics to determine the independent factors associated with unplanned conversion to open. Statistical significance was accepted at p< 0.05.

Outcomes: The overall rate of unplanned conversion to an open nephrectomy in the cohort was 2.2%. The ages of the unplanned conversion group and MIS only group were 62.6 years and 61.3 years, respectively. In basic statistical analysis, preoperative ASA classification greater than 3, a greater than 10% decrease in body weight in 6 months, and stages T3 and T4 were all found to be statistically significant in terms of unplanned conversion to open nephrectomy. Preoperative laboratory values including elevated creatinine (14.2% vs. 6.8%), PTT (12.3% vs. 4.6%), and INR (11.3% vs. 5.5%). Additionally, readmission, transfusion requirements, total operating time, length of hospital stay, acute renal failure, PE, DVT, wound disruption, and unplanned reoperation were found to be significant between the two groups (Table 2). Univariate and multivariate analysis revealed T3b (p = 0.006), and T4 (p < 0.001) staging as well as patients currently on dialysis (0.002) were all significantly associated with the unplanned conversion to open nephrectomy (Table 3).

Conclusion: Unplanned open conversion for nephrectomy has been shown to have adverse events postoperatively. Our study has shown that pT3b stage, pT4 stage, and dialysis dependency were associated with the unplanned conversion to open nephrectomy. The open group had worse clinical outcomes including length of hospital stay, sepsis, pulmonary embolism, lymphocele and lymphatic leak, and unplanned reoperation. These findings may assist in identifying potential predictive factors for this unforeseen intraoperative conversion and increase surveillance to limit complications in this particular group.