Monica S.C. Morgan

Minimally Invasive Percutaneous Treatment of Small Renal Tumors with Irreversible Electroporation: A Single-Center Experience

PURPOSE To evaluate whether irreversible electroporation (IRE) can be used as an ablation technique for small renal tumors (T1a cancers or small benign tumors) and to describe features after ablation on computed tomography (CT) or magnetic resonance (MR) imaging. MATERIALS AND METHODS In this retrospective study, 20 patients (mean age, 65 y ± 12.8 y) underwent CT-guided IRE of T1a renal carcinoma (n = 13) or small benign or indeterminate renal masses < 4 cm in size (n = 7). Mean tumor size was 2.2 cm ± 0.7. The ablation area was verified with contrast-enhanced imaging performed immediately after the procedure to determine technical success. Imaging was performed 6 weeks (20 of 20 patients), 6 months (15 of 20), and 12 months (6 of 20) after ablation. Medical records and CT/MR imaging features of all patients were reviewed for recurrence, symptoms, and complications after treatment. RESULTS Technical success was achieved in all patients (100%); there were no major procedure-related complications. Minor complications occurred in 7 patients, including self-limiting perinephric hematomas, pain difficult to control, and urinary retention. Mean procedure time was 2.0 hours ± 0.7. At 6 weeks, 2 patients required salvage therapy because of incomplete ablation. At 6 months, all 15 patients with imaging studies available had no evidence of recurrence. At 1 year, 1 patient (1 of 6) was noted to have experienced recurrence. CT/MR imaging after IRE ablation demonstrated an area of nonenhancement in the treatment zone that involuted over ~6 months. CONCLUSIONS Renal IRE appears to be a safe treatment for small renal tumors. Tumors treated with IRE demonstrated nonenhancement in the treatment zone with involution on follow-up CT/MR imaging.

Medical management of renal stones

The prevalence of kidney stones is increasing in industrialized nations, resulting in a corresponding rise in economic burden. Nephrolithiasis is now recognized as both a chronic and systemic condition, which further underscores the impact of the disease. Diet and environment play an important role in stone disease, presumably by modulating urine composition. Dietary modification as a preventive treatment to decrease lithogenic risk factors and prevent stone recurrence has gained interest because of its potential to be safer and more economical than drug treatment. However, not all abnormalities are likely to be amenable to dietary therapy, and in some cases drugs are necessary to reduce the risk of stone formation. Unfortunately, no new drugs have been developed for stone prevention since the 1980s when potassium citrate was introduced, perhaps because the long observation period needed to demonstrate efficacy discourages investigators from embarking on clinical trials. Nonetheless, effective established treatment regimens are currently available for stone prevention.

Oncologic Efficacy of Radio Frequency Ablation for Small Renal Masses: Clear Cell vs Papillary Subtype

PURPOSE Current radio frequency ablation series do not distinguish renal cell carcinoma subtypes when reporting oncologic efficacy. Papillary neoplasms may be more amenable to radio frequency ablation than clear cell carcinoma because they are less vascular, which may limit heat energy loss. We report the long-term outcomes of patients treated with radio frequency ablation for small renal masses by renal cell carcinoma subtype. MATERIALS AND METHODS The records of patients undergoing radio frequency ablation for small renal masses (cT1a) at 2 institutions from March 2007 to July 2012 were retrospectively reviewed. Patients were included in analysis if they had biopsy confirmed clear cell or papillary renal cell carcinoma histology. Patients had at least 1 contrast enhanced cross-sectional image following radio frequency ablation. Demographic data between tumor subtypes were compared using the paired t-test. Oncologic outcomes were determined by Kaplan-Meier survival analysis and survivor curves were compared with the log rank test. RESULTS A total of 229 patients met study inclusion criteria. There were 181 clear cell tumors and 48 papillary tumors. Median followup was 33.2 months. There was no difference between tumor groups based on patient age, tumor size or grade, or months of followup. Five-year disease-free survival was 89.7% for clear cell tumors and 100% for papillary tumors (p = 0.041). There was no significant difference in overall survival (88.4% vs 89.6%, p = 0.764). CONCLUSIONS Radio frequency ablation outcomes seem to be determined in part by renal cell carcinoma subtype with clear cell renal tumors having less favorable outcomes. We hypothesize that this is due to differences in tumor vascularity. Our experience suggests that future tumor ablation studies should consider reporting outcomes based on tumor cell types.

LESS and NOTES instrumentation: future.

Purpose of review Laparoendoscopic single-site surgery (LESS) and natural orifice transluminal endoscopic surgery (NOTES) are novel techniques with potential to minimize the morbidity of surgery. Challenging ergonomics, instrument clashing, and the lack of true triangluation still remain great concerns. Recent findings New technological developments in instrument design have been created to enhance clinical applicability of these techniques. Further technological advancements including the incorporation of novel robotic surgical platforms (R-LESS) exploit the ergonomic benefits in an attempt to further advance LESS surgery. Promising devices include magnetic anchoring and guidance systems that have the potential to allow external manoeuvring of intracorporeal instruments while facilitating triangulation and reducing clashing. As well, the benefit of miniature in-vivo robots that can be placed endoscopically intra-abdominally and controlled wirelessly will allow internal manipulation of tissue from internal repositionable platforms. Summary It remains to be seen whether LESS or NOTES will prove their clinical benefit over standard laparoscopic or robotic procedures. In this chapter, we review the current LESS and NOTES technology, and focus on new innovations and research in the field.

Equivocal Ureteropelvic Junction Obstruction on Diuretic Renogram—Should Minimally Invasive Pyeloplasty be Offered to Symptomatic Patients?

PURPOSE Equivocal ureteropelvic junction obstruction refers to clinical symptoms and/or other radiological suggestions of possible ureteropelvic junction obstruction but with inconclusive results of obstruction on diuretic renogram. We evaluated long-term outcomes in patients with equivocal ureteropelvic junction obstruction treated with minimally invasive pyeloplasty. MATERIALS AND METHODS We retrospectively analyzed the records of 125 consecutive patients who underwent minimally invasive pyeloplasty as performed by a single surgeon from May 2004 to July 2013. Of 98 patients with followup those with more than 6-month followup were included in analysis. Equivocal ureteropelvic junction obstruction, defined as half-life less than 20 minutes on diuretic renogram, was identified in 23 patients. All patients underwent transperitoneal minimally invasive pyeloplasty. We evaluated patient demographics, preoperative and postoperative symptoms and renal function. RESULTS The 16 female and 7 male patients with equivocal ureteropelvic junction obstruction had flank pain and associated hydronephrosis on imaging. At a median followup of 20.2 months (range 7 to 75) 95.7% of patients with equivocal obstruction achieved complete symptom resolution. Mean ± SD preoperative and postoperative half-life was 14.1 ± 3.7 and 7.4 ± 4.2 minutes, respectively, for an improvement of 6.7 minutes (p < 0.001). In 1 patient (4.3%) with equivocal obstruction of a complicated iatrogenic etiology treatment ultimately failed postoperatively and endopyelotomy was required. There was no statistically significant difference in clinical or radiological success between the equivocal obstruction group and the 75 patients treated with minimally invasive pyeloplasty for definitive ureteropelvic junction obstruction (p = 0.44 and 0.07, respectively). CONCLUSIONS In patients with radiographic equivocal ureteropelvic junction obstruction and flank pain minimally invasive pyeloplasty efficaciously provides symptomatic relief and functional preservation. Results are comparable to those in patients with high grade obstruction.

Comparative Effects of Irreversible Electroporation, Radiofrequency Ablation, and Partial Nephrectomy on Renal Function Preservation in a Porcine Solitary Kidney Model

OBJECTIVE To evaluate kidney function preservation or regeneration and pathological changes post-irreversible electroporation (IRE) in comparison with partial nephrectomy and radiofrequency ablation (RFA) in a solitary kidney porcine model. Tissue ablation using IRE has been reported to spare critical anatomic structures within or near the ablation zone with associated regeneration of adjacent parenchyma, possibly offering functional preservation. METHODS Fifteen pigs initially underwent laparoscopic nephrectomy. The lower third of the remaining kidney was then ablated or removed with either IRE, RFA, or partial nephrectomy. Serum creatinine (SCr) was measured at baseline, 24 hours, 3, 7, 14, and 28 days postoperatively. The impact of the type of procedure on SCr over time was evaluated. Acute and chronic histological changes were analyzed and cellular viability was assessed using nicotinamide adenine dinucleotide staining in the IRE ablations. RESULTS Ten ablations (5 IRE, 5 RFA) and 5 partial nephrectomies of the entire lower third of a solitary kidney were performed. The type of procedure did not affect SCr significantly at baseline (P = .14) or change in SCr over time (P = .48). Histologically, IRE and RFA lesions showed similar findings including coagulative necrosis that progressively was replaced by reparative stromal changes and fibrous tissue. Nicotinamide adenine dinucleotide staining of the IRE lesions at 14 and 28 days showed no viability in the necrotic areas with viable tissue at the margins demonstrating reparative changes. CONCLUSION Large volume IRE ablation of normal renal parenchyma in the porcine model does not provide a functional advantage as compared with conventional renal tumor treatments.

Use of an Electronic Medical Record to Assess Patient-Reported Morbidity Following Ureteroscopy.

BACKGROUND AND PURPOSE With the extensive documentation afforded by our electronic medical record (EMR), we observed an unusually high number of patient-initiated encounters following ureteroscopy (URS). We sought to quantify and categorize patient encounters following URS to determine if we could identify avoidable common problems. MATERIALS AND METHODS Following IRB approval, we reviewed the records of 298 consecutive patients with stones who underwent 314 URS procedures between July 2013 and November 2014. Patient demographics, stone characteristics and operative details, as well as telephone encounters, secure online patient-initiated (MyChart) messages, and emergency department (ED) visits following URS were extracted from our EMR (Epic, Verona, WI). We performed univariate (UVA) and multivariate (MVA) analysis to identify factors predictive of postoperative patient encounters and compared URS patients to a group of 56 patients undergoing transurethral resection of bladder tumor (TURBT) for number and type of encounters. RESULTS We identified 443 encounters generated by 201 URS patients, including 334 telephone calls, 71 MyChart messages, and 38 ED visits. Among these encounters, 352 (79%) were medically related (pain comprised 45%) and the remainder involved scheduling issues. By UVA age, bilateral versus unilateral URS, stone location (both kidney and ureter), ureteral access sheath size, and total number of stones predicted a postoperative encounter. By MVA, only younger age and larger UAS size were independent predictors. When compared with TURBT patients, URS patients had a 2.5-fold higher risk of having a pain-related postoperative encounter (OR 2.54, 95% CI 1.08-7.04, P=0.03). CONCLUSIONS Among patients undergoing URS for stones, two-thirds made unprompted contact with a healthcare provider and 80% of contacts involved postoperative pain, a finding that is distinct from another endoscopic procedure that does not involve upper tract manipulation. Patients do not perceive URS as the benign procedure doctors do.

Do Urinary Cystine Parameters Predict Clinical Stone Activity

Purpose: An accurate urinary predictor of stone recurrence would be clinically advantageous for patients with cystinuria. A proprietary assay (Litholink, Chicago, Illinois) measures cystine capacity as a potentially more reliable estimate of stone forming propensity. The recommended capacity level to prevent stone formation, which is greater than 150 mg/l, has not been directly correlated with clinical stone activity. We investigated the relationship between urinary cystine parameters and clinical stone activity. Materials and Methods: We prospectively followed 48 patients with cystinuria using 24‐hour urine collections and serial imaging, and recorded stone activity. We compared cystine urinary parameters at times of stone activity with those obtained during periods of stone quiescence. We then performed correlation and ROC analysis to evaluate the performance of cystine parameters to predict stone activity. Results: During a median followup of 70.6 months (range 2.2 to 274.6) 85 stone events occurred which could be linked to a recent urine collection. Cystine capacity was significantly greater for quiescent urine than for stone event urine (mean ± SD 48 ± 107 vs –38 ± 163 mg/l, p <0.001). Cystine capacity significantly correlated inversely with stone activity (r = –0.29, p <0.001). Capacity also correlated highly negatively with supersaturation (r = –0.88, p <0.001) and concentration (r = –0.87, p <0.001). Using the suggested cutoff of greater than 150 mg/l had only 8.0% sensitivity to predict stone quiescence. Decreasing the cutoff to 90 mg/l or greater improved sensitivity to 25.2% while maintaining specificity at 90.9%. Conclusions: Our results suggest that the target for capacity should be lower than previously advised.

Detecting positive surgical margins: utilisation of light‐reflectance spectroscopy on ex vivo prostate specimens

To assess the efficacy of light‐reflectance spectroscopy (LRS) to detect positive surgical margins (PSMs) on ex vivo radical prostatectomy (RP) specimens.

Prompt Management of Anastomotic Leak or Acute Obstruction after Minimally Invasive Pyeloplasty with Percutaneous Nephrostomy Preserves Outcomes

PURPOSE Urine leak or obstruction in the early postoperative period is a worrisome complication of pyeloplasty. Suboptimal management may risk long-term success. We evaluated percutaneous nephrostomy to manage complications of minimally invasive pyeloplasty. MATERIALS AND METHODS We retrospectively analyzed the records of 125 patients who underwent minimally invasive pyeloplasty performed by a single surgeon from May 2004 to May 2013. All complications were catalogued and patients with anastomotic urine leakage or postoperative obstruction were identified. Less than 7 days postoperatively percutaneous nephrostomy was done in each case. Surgical success was defined as resolution of flank pain and/or improved half-time (less than 20 minutes) on diuretic renogram. RESULTS Early percutaneous nephrostomy placement was required in 12 patients (9.6%) for symptomatic obstruction (6) or anastomotic urine leakage (6) a median of 4.5 days (range 2 to 7) postoperatively. Percutaneous nephrostomies remained in place a median of 9.5 days (range 5 to 42). Median followup was 15 months (range 2 to 80). Mean half-time was 36.4 minutes preoperatively and 11.1 minutes postoperatively. Continued postoperative obstruction (half-time greater than 20 minutes) was documented in 1 (8%) and 13 patients (11.5%) who did and did not require percutaneous nephrostomy placement, respectively. There was no statistical difference in radiological and clinical success rates between the percutaneous nephrostomy group and the 113 patients in whom minimally invasive pyeloplasty was uncomplicated (p = 0.74 and 0.28, respectively). CONCLUSIONS In patients treated with minimally invasive pyeloplasty aggressive management of acute urinary complications with percutaneous nephrostomy placement preserved radiographic and symptomatic outcomes that were comparable to those in patients without complications.