Daily Ecological Momentary Assessments of Pain and Ability to Work After Ureteroscopy and Stenting.

Introduction: Ureteral stents can cause significant patient discomfort, yet the temporal dynamics and impact on activities remain poorly characterized. We employed an automated tool to collect daily ecological momentary assessments (EMAs) regarding pain and the ability to work following ureteroscopy with stenting. Our aims were to assess feasibility and better characterize the postoperative patient experience. Materials and Methods: As an exploratory endpoint within an ongoing clinical trial, patients undergoing ureteroscopy with stenting were asked to complete daily EMAs for 10 days postoperatively or until the stent was removed. Questionnaires were distributed through text messages and included a pain scale (0-10) and a single item from the validated Patient-Reported Outcomes Measurement Information System Ability to Participate in Social Roles and Activities instrument, as well as days missed from work or school. Results: Among the first 65 trial participants, 59 completed at least 1 EMA (overall response rate 91%). Response rates were >85% for each time point through postoperative day (POD)10. Median respondent age was 58 years (interquartile range [IQR] 50-67), and 56% were female. Stones were 54% renal and 46% ureteral, with a median diameter of 9 mm (IQR 7-10). Median stent dwell time was 7 days (IQR 6-8). Pain scores were highest on POD1 (median score 4) and declined on each subsequent day, reaching a median score of 2 on POD5. Sixty-three percent of patients on POD1 reported that they had trouble performing their usual work at least sometimes, but by POD5, this was <50% of patients. Patients who work or attend school reported a median of 1 day missed (IQR 0-2). Conclusions: An automated daily EMA system for capturing patient-reported outcomes was demonstrated to be feasible with sustained excellent engagement. Patients with stents reported the worst pain and interference with work on POD1, with steady improvements thereafter, and by POD5, the majority of patients had minimal pain or trouble performing their usual work. This work is associated with a registered clinical trial [NCT05026710].

Prevalence of ATTR-CA and high-risk features to guide testing in patients referred for TAVR.

PURPOSE: Transthyretin cardiac amyloidosis (ATTR-CA) is thought to be prevalent in patients with severe aortic stenosis (AS) who are referred for transcatheter aortic valve replacement (TAVR). However, prior studies were published when TAVR was only offered to elderly, inoperable, and high-risk patients. The aim of this study was to reevaluate the prevalence of ATTR-CA in a contemporary TAVR population and identify high-risk features to guide referral for technetium-99 pyrophosphate scan (99mTc-PyP scan) screening. METHODS: Patients seen in a multidisciplinary TAVR clinic for severe AS 70 years and older were referred for a 99mTc-PyP scan to evaluate for ATTR-CA. The primary outcome was the percent with a positive scan. The discriminatory ability of high-risk features was assessed to develop a more judicious screening system. RESULTS: Over the study period, 380 patients underwent screening, and 20 patients (5.3%) had a positive scan, with 17 patients having confirmed ATTR-CA, 1 patient deferring confirmatory testing (combined 4.7%), 1 having light chain amyloidosis, and 1 negative on biopsy. Compared to other patient and echocardiographic measures, elevated NT-pro BNP (> 1000 ng/L) was the best discriminator on who should be referred for 99mTc-PyP scan screening, with a sensitivity of 90% and a negative predictive value of 99%. CONCLUSION: The prevalence of ATTR-CA may be lower in a contemporary TAVR population due to its expanded indication for low-risk patients. NT-pro BNP is a simple test that can improve screening yield and more judiciously guide screening for ATTR-CA in this at-risk population. Comparison of the original versus the proposed algorithm.

How I Do It: Ureteroscopy and high-power holmium laser lithotripsy to treat renal stones.

In North America, ureteroscopy has become the most popular treatment modality for upper urinary tract urinary calculi. Herein we describe our technique for the treatment of renal stones with flexible ureteroscopy and high-power holmium laser lithotripsy. We discuss preoperative planning, intraoperative strategies, and laser settings for a high-frequency dusting technique with the goal to provide optimal patient outcomes.

Improving the Quality of Upper Urinary Tract Stone Surgery: External Validation of a Statewide Collaborative's Efforts to Reduce Emergency Department Visits After Ureteroscopy.

PURPOSE: The ROCKS (Reducing Operative Complications from Kidney Stones) program in MUSIC (Michigan Urological Surgery Improvement Collaborative) was created to optimize ureteroscopy outcomes. Through data collection, distribution of reports, patient education, and standardization of medication, post-ureteroscopy emergency department visits in Michigan have declined. It is unclear whether this is because of statewide quality efforts or due to national trends. We therefore sought to understand emergency department visit rates in Michigan compared to a national data set. MATERIALS AND METHODS: We compared the MUSIC ROCKS clinical registry in Michigan against a national cohort, Optum's de-identified Clinformatics Data Mart, from 2016-2021 (excluding Michigan). We identified patients who underwent ureteroscopy and the proportion who had a postoperative emergency department visit within 30 days. Emergency department rates were modeled over time, adjusting for age, gender, comorbidity, and ureteral stenting. RESULTS: We identified 24,688 patients in MUSIC ROCKS and 99,340 in the Clinformatics Data Mart database who underwent ureteroscopy. The risk-adjusted emergency department visit rate in MUSIC ROCKS significantly declined over the study period (10.5% in 2016 to 6.9% in 2021, P < 0.001) while the mean emergency department visit rate in the Clinformatics Data Mart cohort was 9.9% and did not change over time (9.6% in 2016 to 10% in 2021). Comparing emergency department visits between the cohorts, the MUSIC ROCKS rate significantly declined relative to the Clinformatics Data Mart (P < 0.001) over the study period. CONCLUSIONS: Postoperative emergency department visit rates in Michigan have declined significantly after ureteroscopy since the establishment of MUSIC ROCKS. This decline outpaced national rates, providing evidence that systematic quality initiatives can improve urological care.

Non-invasive hemoglobin estimation for preoperative anemia screening.

BACKGROUND: Preoperative anemia is common and associated with adverse postoperative outcomes. Assessment of hemoglobin concentrations may facilitate optimization prior to surgery. However, phlebotomy-based hemoglobin measurement may contribute to patient discomfort and iatrogenic blood loss, which makes non-invasive hemoglobin estimation attractive in this setting. STUDY DESIGN AND METHODS: This is a prospective study of adult patients presenting for preoperative evaluation before elective surgery at a tertiary care medical center. The Masimo Pronto Pulse CO-Oximeter was utilized to estimate blood hemoglobin concentrations (SpHb), which were then compared with hemoglobin concentrations obtained via complete blood count. Receiver operating curves were used to identify SpHb values maximizing specificity for anemia detection while meeting a minimum sensitivity of 80%. RESULTS: A total of 122 patients were recruited with a median (interquartile range) age of 66 (58, 72) years. SpHb measurements were obtained in 112 patients (92%). SpHb generally overestimated hemoglobin with a mean (± 1.96 × standard deviation) difference of 0.8 (-2.2, 3.9) g/dL. Preoperative anemia, defined by hemoglobin <12.0 g/dL in accordance with institutional protocol, was present in 22 patients (20%). The optimal SpHb cut-point to identify anemia was 13.5 g/dL: sensitivity 86%, specificity 81%, negative predictive value 96%, and positive predictive value 53%. Utilizing this cut-point, 60% (73/122) of patients could have avoided phlebotomy-based hemoglobin assessment, while an anemia diagnosis would have been missed in <3% (3/122). CONCLUSION: The use of SpHb devices for anemia screening in surgical patients is feasible with the potential to reliably rule-out anemia despite limited accuracy.

Profound facial bleeding after buccal mucosa graft harvest - A rare case of facial artery pseudoaneurysm.

Facial artery pseudoaneurysms are exceedingly rare events that can occur as a complication of oral maxillofacial surgery or facial trauma. The management of such pseudoaneurysms following buccal mucosa graft harvest for urinary reconstructive indications has not previously been described. Here, we describe a facial artery pseudoaneurysm that presented as repeated, episodic facial bleeding episodes following buccal mucosal harvest for a patient undergoing urethroplasty.

Initial Experience Performing "Cautery-Free Waterjet Ablation of the Prostate".

Introduction: Herein, we describe our initial experience performing waterjet ablation of the prostate without electrocautery. Materials and Methods: A retrospective review of patients undergoing Aquablation for benign prostatic hyperplasia between February and September 2019 was performed. A standardized perioperative protocol for optimizing hemostasis was implemented. The primary endpoint was to define bleeding complications perioperatively and up to 30 days postoperatively after Aquablation. Bleeding complications included hematuria requiring prolonged continuous bladder irrigation, drop in hemoglobin requiring transfusion, or take back to operating room for evacuation of bladder clots and bladder fulguration. Bivariable analysis using Fisher's exact test and unpaired t-tests were used to identify factors associated with bleeding complications. Results: Thirty-two patients underwent Aquablation over the study period. Average preoperative international prostate symptom score was 20 (range: 13-34) and Qmax was 7 mL/s (range: 0-11). Mean prostate volume was 65 cc (range: 30-200 cc). Average perioperative change in hemoglobin was 1.3 g/dL (range: -0.3 to 4.2 g/dL). Eight patients (25%) experienced bleeding complications. Three (9.4%) required blood transfusions. On Fisher's exact test, prostate volume (91 cc vs 55 cc; p = 0.0361) and preoperative prostate-specific antigen (6.6 vs 2.9; p = 0.0218) were associated with postoperative bleeding. Conclusions: Performing waterjet ablation of the prostate without the use of electrocautery after waterjet treatment to control bleeding resulted in significant bleeding complications (25% of our cohort) during our initial experience. A combination of traction and focal bladder neck electrocautery is the best strategy to minimize bleeding complications after Aquablation.

How I do it: Aquablation in very large prostates (> 150 mL).

Aquablation has been well-studied in prostates sizes up to 150 mL. Recently, American Urological Association guidelines distinguish surgical interventions for men with large prostates (80 mL-150 mL) and now very large prostates (> 150 mL). Readers will gain an understanding of how to use Aquablation in the very large prostate size category.

Effective Penetration of a Liposomal Formulation of Bleomycin through Ex-Vivo Skin Explants from Two Different Species.

Bleomycin is a chemotherapy agent that, when administered systemically, can cause severe pulmonary toxicity. Bleosome is a novel formulation of bleomycin encapsulated in ultra-deformable (UD) liposomes that may be applicable as a topical chemotherapy for diseases such as non-melanoma skin cancer. To date, the ability of Bleosome to effectively penetrate through the skin has not been evaluated. In this study, we investigated the ability of Bleosome to penetrate through ex vivo skin explants from dogs and horses. We visualized the penetration of UD liposomes through the skin by transmission electron microscopy. However, to effectively image the drug itself we fluorescently labeled bleomycin prior to encapsulation within liposomes and utilized multiphoton microscopy. We showed that UD liposomes do not penetrate beyond the stratum corneum, whereas bleomycin is released from UD liposomes and can penetrate to the deeper layers of the epidermis. This is the first study to show that Bleosome can effectively penetrate through the skin. We speculate that UD liposomes are penetration enhancers in that UD liposomes carry bleomycin through the outer skin to the stratum corneum and then release the drug, allowing diffusion into the deeper layers. Our results are comparative in dogs and horses and warrant further studies on the efficacy of Bleosome as topical treatment.

Men with lower urinary tract symptoms secondary to BPH undergoing Aquablation with very large prostates (> 150 mL).

INTRODUCTION: The AUA guidelines for benign prostatic hyperplasia distinguish treatments based upon prostate volume (PV), particularly for very large prostates (> 150 mL). While the clinical outcomes and benefits of Aquablation have been studied for men with average and large prostates, it is unknown whether this technology can be used for very large prostates. MATERIALS AND METHODS: Men with PV > 150 mL undergoing Aquablation were identified retrospectively from four North American hospitals. The surgical times and clinical outcomes of men with very large prostates (> 150 mL) were compared to data from men with average PV ≤ 80 mL (WATER study) and large PV 80 mL-150 mL (WATER II study). RESULTS: The average PV of men who underwent Aquablation with very large prostates was 209 mL ± 56 (n = 34, range 151-362 mL), large PV 107 mL ± 20 (n = 101, range 80-150 mL) and average PV 54 mL ± 16 (n = 116, range 30-80 mL). For men with PV > 150 mL, baseline IPSS was 19 ± 6. With a mean follow up of 7 ± 9 months, the IPSS improved to 7 ± 5 (p < 0.001). Peak urinary flow rate, Qmax, improved from 7 ± 4 mL/s to 19 ± 5 mL/s (p<0.001). Compared to the two other PV groups, there were no differences in terms of improvements in IPSS, quality of life, or uroflowmetry. There were no reports of transfusions (0%) in the cohort of men with very large prostates. CONCLUSIONS: In the present study, we demonstrate that Aquablation is effective and safe in prostates greater than 150 mL while showing consistent outcomes compared to average and large prostates sizes.

Implementation of a Comprehensive Patient Blood Management Program for Hospitalized Patients at a Large United States Medical Center.

OBJECTIVE: To assess changes in inpatient transfusion utilization and patient outcomes with implementation of a comprehensive patient blood management (PBM) program at a large US medical center. PATIENTS AND METHODS: This is an observational study of graduated PBM implementation for hospitalized adults (age ≥18 years) from January 1, 2010, through December 31, 2017, at two integrated hospital campuses at a major academic US medical center. Allogeneic transfusion utilization and clinical outcomes were assessed over time through segmented regression with multivariable adjustment comparing observed outcomes against projected outcomes in the absence of PBM activities. RESULTS: In total, 400,998 admissions were included. Total allogeneic transfusions per 1000 admissions decreased from 607 to 405 over the study time frame, corresponding to an absolute risk reduction for transfusion of 6.0% (95% confidence interval [CI]: 3.6%, 8.3%; P<.001) and a 22% (95% CI: 6%, 37%; P=.006) decrease in the rate of transfusions over projected. The risk of transfusion decreased for all blood components except cryoprecipitate. Transfusion reductions were experienced for all major surgery types except liver transplantation, which remained stable over time. Hospital length of stay (multiplicative increase in geometric mean 0.85 [95% CI: 0.81, 0.89]; P<.001) and incident in-hospital adverse events (absolute risk reduction: 1.5% [95% CI: 0.1%, 3.0%]; P=.04) were lower than projected at the end of the study time frame. CONCLUSION: Patient blood management implementation for hospitalized patients in a large academic center was associated with substantial reductions in transfusion utilization and improved clinical outcomes. Broad-scale implementation of PBM in US hospitals is feasible without signal for patient harm.

Pain management strategies in penile implantation.

The opioid epidemic continues to be a serious public health concern. Many have pointed to prescription drug misuse as a nidus for patients to become addicted to opioids and as such, urologists and other surgical subspecialists must critically define optimal pain management for the various procedures performed within their respective disciplines. Controlling pain following penile prosthesis implantation remains a unique challenge for urologists, given the increased pain patients commonly experience in the postoperative setting. Although most of the existing urological literature focuses on interventions performed in the operating room, there are many studies that examine the role of preoperative adjunctive pain medicine in diminishing postoperative narcotic requirements. There are relatively few studies looking at postoperative strategies for managing pain in prosthetic surgery with follow-up past the immediate hospitalization. This review assess the various strategies employed for managing pain following penile implantation through the lens of the current state of the opioid crisis, thus examining how urologists can responsibly treat pain without contributing to the growing threat of opioid addiction.

A study protocol for a randomised controlled trial evaluating the effects of intraoperative computed tomography on the outcomes of zygomatic fractures.

BACKGROUND: Zygomaticomaxillary complex (ZMC) and zygomatic arch (ZA) fractures are common injuries resulting from facial trauma and frequently require surgical management (Huang et al., Craniomaxillofac Trauma Reconstr 8(4):271-6, 2015). A substantial number of post-operative functional and cosmetic complications can arise from the surgical management of these fractures. These include scarring, inadequate facial profile restoration, facial asymmetries and diplopia (Ellis et al. J Oral Maxillofac Surg 54(4):386-400, 1996; Yang et al. Oral Maxillofac Surg Clin North Am 23(1):31-45, 2011; Kloss et al. Int J Oral Maxillofac Surg 40(1):33-7, 2011). Intuitively, most of these aforementioned complications arise as a result of inadequate fracture reduction; however, current standard practice is to assess reduction post-operatively through plain radiographs or computed tomography (CT) scans. The role of intra-operative CT scanning to assess the reduction of ZMC/ZA fractures and the potential impact on complications, has thus far not been established. METHODS: This is a prospective randomised controlled trial currently being undertaken at the Royal Brisbane and Women's Hospital. All patients who require operative management of their ZMC or ZA fractures are offered enrollment in the trial. The patients are randomised into two groups: interventional (intra-operative CT) and control (no intra-operative CT). All patients in each group will have post-operative radiographs taken. From these radiographs, the reduction of the ZMC and/or ZA fracture is graded by a blinded assessor. Patients will be reviewed in clinic at 1 week and 6 weeks post-surgery. During these consultations, all patients will be assessed for scarring, diplopia, facial profile restoration and need for revision surgery. DISCUSSION: Many complications associated with surgical management of ZMC and ZA fractures involve poor aesthetic results as a direct consequence of inadequate fracture reduction. Inadequate fracture reduction is predictable given that small incisions are used and only limited visualisation of the fractures is possible during the procedure. This is due to a desire to limit scarring and reduce the risk of damage to vital structures in an aesthetically sensitive region of the body. It follows that an intraoperative adjunctive tool such as a CT scan, which can assist in visualisation of the fractures and the subsequent reduction, could potentially improve reduction and reduce complications. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry, ACTRN12616000693426 . Registered on 26 May 2016.

Implementation of a patient blood management program in hematopoietic stem cell transplantation (Editorial, p. 2763).

BACKGROUND: Recipients of hematopoietic stem cell transplantation (HSCT) are among the highest consumers of allogeneic red blood cell (RBC) and platelet (PLT) components. The impact of patient blood management (PBM) efforts on HSCT recipients is poorly understood. STUDY DESIGN AND METHODS: This observational study assessed changes in blood product use and patient-centered outcomes before and after implementing a multidisciplinary PBM program for patients undergoing HSCT at a large academic medical center. The pre-PBM cohort was treated from January 1 through September 31, 2013; the post-PBM cohort was treated from January 1 through September 31, 2015. RESULTS: We identified 708 patients; 284 of 352 (80.7%) in the pre-PBM group and 225 of 356 (63.2%) in the post-PBM group received allogeneic RBCs (p < 0.001). Median (interquartile range [IQR]) RBC volumes were higher before PBM than after PBM (3 [2-4] units vs. 2 [1-4] units; p = 0.004). A total of 259 of 284 pre-PBM patients (91.2%) and 57 of 225 (25.3%) post-PBM patients received RBC transfusions when hemoglobin levels were more than 7 g/dL (p < 0.001). The median (IQR) PLT transfusion quantities was 3 (2-5) units for pre-PBM patients and 2 (1-4) units for post-PBM patients (p < 0.001). For patients with PLT counts of more than 10 × 109 /L, a total of 1219 PLT units (73.4%) were transfused before PBM and 691 units (48.8%) were transfused after PBM (p < 0.001). Estimated transfusion expenditures were reduced by $617,152 (18.3%). We noted no differences in clinical outcomes or transfusion-related adverse events. CONCLUSION: Patient blood management implementation for HSCT recipients was associated with marked reductions in allogeneic RBC and PLT transfusions and decreased transfusion-related costs with no detrimental impact on clinical outcomes.

Risk Factors for Postoperative Fever and Systemic Inflammatory Response Syndrome After Ureteroscopy for Stone Disease.

Introduction: Infectious complications after ureteroscopy (URS) for stone disease lead to emergency department visits, hospitalizations, and other costly health care utilization. The objective of our study was to identify risk factors for postoperative fever (POF) and systemic inflammatory response syndrome (SIRS) after URS for stone disease. Materials and Methods: We performed a retrospective cohort study on 2746 patients who underwent 3298 URS for stone disease at Geisinger from 2008 to 2016. A univariate analysis tested the associations between candidate demographic, preoperative, and intraoperative predictors and the primary outcome of POF (temperature >100.4°F) or SIRS. Variables with a p-value of <0.05 on univariate comparisons were entered into a random-effects logistic regression model. The final model used backward elimination random-effects logistic regression to identify predictors most predictive of POF/SIRS. Results: Overall, 229 (6.9%) of 3298 URS had POF/SIRS. On univariate analysis, individuals with POF/SIRS were older, had higher mean body mass index, higher Charlson Comorbidity Index (CCI), bilateral and larger stones, stone location in the kidney, positive preoperative urine culture, pre-stented, and longer surgical times. In the final model, female gender (adjusted odds ratio [OR] 1.6, 95% confidence interval [CI] 1.19-2.15), surgical time (adjusted OR 1.01, 95% CI 1.0-1.01), CCI ≥2 (adjusted OR 1.86, 95% CI 1.29-2.67), and positive preoperative urine culture (adjusted OR 1.53, 95% CI 1.06-2.22) were the most significant predictors of POF/SIRS. Conclusions: Female gender, longer surgical time, medical complexity, and positive preoperative urine culture are associated with POF/SIRS after URS. These data may be used to identify and counsel high-risk individuals.

Optimizing Blood Transfusion Practices Through Bundled Intervention Implementation in Patients With Gynecologic Cancer Undergoing Laparotomy.

OBJECTIVE: To examine blood transfusion practices and develop a standardized bundle of interventions to address the high rate of perioperative red blood cell transfusion among patients with ovarian and endometrial cancer. METHODS: This was a retrospective cohort study. Our primary aim was to determine whether an implemented bundled intervention was associated with a reduction in perioperative red blood cell transfusions among cases of laparotomy for cancer. Secondary aims included comparing perioperative demographic, surgical, complication, and cost data. Interventions included blood transfusion practice standardization using American Society of Anesthesiologists guidelines, an intraoperative hemostasis checklist, standardized intraoperative fluid status communication, and evidence-based use of tranexamic acid. Prospective data from women undergoing laparotomy for ovarian or endometrial cancer from September 28, 2015, to May 31, 2016, defined the study cohort and were compared with historical controls (September 1, 2014, to September 25, 2015). Outcomes were compared in the full unadjusted cohorts and in propensity-matched cohorts. RESULTS: In the intervention and historical cohorts, respectively, 89 and 184 women underwent laparotomy for ovarian cancer (n=74 and 152) or advanced endometrial cancer (n=15 and 32). Tranexamic acid was administered in 54 (60.7%) patients. The perioperative transfusion rate was lower for the intervention group compared with historical controls (18.0% [16/89] vs 41.3% [76/184], P<.001), a 56.4% reduction. This improvement in the intervention group remained significant after propensity matching (16.2% [13/80] vs 36.2% [29/80], P=.004). The hospital readmission rate was also lower for the intervention group compared with historical controls (1.1% [1/89] vs 12.5% [23/184], P=.002); however, this improvement did not attain statistical significance after propensity matching (1.2% [1/80] vs 7.5% [6/80], P=.12). Cost analysis demonstrated that this intervention was cost-neutral during index hospitalization plus 30-day follow-up. CONCLUSION: Application of a standardized bundle of evidence-based interventions was associated with reduced blood use in our gynecologic oncology practice.

Changes in International Normalized Ratios After Plasma Transfusion of Varying Doses in Unique Clinical Environments.

BACKGROUND: Plasma transfusion is commonly performed for the correction of abnormal coagulation screening tests. The goal of this investigation was to assess the relationship between the dose of plasma administered and changes in coagulation test results in a large and diverse cohort of patients with varying levels of coagulation abnormalities and comorbid disease and in a variety of clinical settings. METHODS: In this single-center historical cohort study, all plasma transfusion episodes in adult patients with abnormal coagulation screening tests were extracted between 2011 and 2015. The primary outcome was the proportion of patients attaining normal posttransfusion international normalized ratio (INR ≤ 1.1) with secondary outcomes including the proportion of patients attaining partial normalization of INR (INR ≤ 1.5) or at least 50% normalization in pretransfusion values with respect to an INR of 1.1. RESULTS: In total, 6779 unique patients received plasma with a median (quartiles) pretransfusion INR of 1.9 (1.6-2.5) and a median transfusion volume of 2 (2-3) units. The majority (85%) of transfusions occurred perioperatively, with 20% of transfusions administered prophylactically before a procedure. The median decrease in INR was 0.4 (0.2-0.8). Complete INR normalization was obtained in 12%. Reductions in INR were modest with pretransfusion INR values <3. Patients receiving ≥3 units of plasma were more likely to achieve at least 50% normalization in INR than those receiving ≤2 units (68% vs 60%; P < .001). CONCLUSIONS: Changes in INR after plasma transfusion were modest at typically used clinical doses, particularly in those with less severely deranged baseline coagulation screening tests. Further studies are necessary to assess the relationships between plasma-mediated changes in INR and clinical outcomes.

External Validation of Contact Surface Area as a Predictor of Postoperative Renal Function in Patients Undergoing Partial Nephrectomy.

PURPOSE: We sought to externally validate a mathematical formula for tumor contact surface area as a predictor of postoperative renal function in patients undergoing partial nephrectomy for renal cell carcinoma. MATERIALS AND METHODS: We queried a prospectively maintained kidney cancer database for patients who underwent partial nephrectomy between 2014 and 2016. Contact surface area was calculated using data obtained from preoperative cross-sectional imaging. The correlation between contact surface area and perioperative variables was examined. The correlation between postoperative renal functional outcomes, contact surface area and the R.E.N.A.L. (radius, exophytic/endophytic properties, nearness of tumor to collecting system or sinus, anterior/posterior, location relative to polar lines and tumor touches main renal artery or vein) nephrometry score was also assessed. RESULTS: A total of 257 patients who underwent partial nephrectomy had sufficient data to enter the study. Median contact surface area was 14.5 cm2 (IQR 6.2-36) and the median nephrometry score was 9 (IQR 7-10). Spearman correlation analysis showed that contact surface area correlated with estimated blood loss (rs = 0.42, p <0.001), length of stay (rs = 0.18, p = 0.005), and percent and absolute change in the estimated glomerular filtration rate (rs = -0.77 and -0.78, respectively, each p <0.001). On multivariable analysis contact surface area and nephrometry score were independent predictors of the absolute change in the estimated glomerular filtration rate (each p <0.001). ROC curve analysis revealed that contact surface area was a better predictor of a greater than 20% postoperative decline in the estimated glomerular filtration rate compared with the nephrometry score (AUC 0.94 vs 0.80). CONCLUSIONS: Contact surface area correlated with the change in postoperative renal function after partial nephrectomy. It can be used in conjunction with the nephrometry score to counsel patients about the risk of renal functional decline after partial nephrectomy.