Brian R. Matlaga

Trends in Renal Surgery: Robotic Technology is Associated with Increased Use of Partial Nephrectomy

PURPOSE Underuse of partial vs radical nephrectomy for renal tumors was noted in recent population based analyses. An explanation is the learning curve associated with laparoscopic partial nephrectomy. We analyzed state trends in renal surgery and their relationship to the introduction of robotic technology. MATERIALS AND METHODS We used the Maryland HSCRC (Health Services Cost Review Commission) database to identify patients who underwent radical or partial nephrectomy, or renal ablation from 2000 to 2011. Utilization trends, and associated patient and hospital factors were analyzed using multivariate logistic regression. ICD-9 robotic modifier codes were established in October 2008. RESULTS Of the 14,260 patients included in analysis 11,271 (79.0%), 2,622 (18.4%) and 367 (2.6%) underwent radical and partial nephrectomy, and renal ablation, respectively. Partial nephrectomy increased from 8.6% in 2000 to 27% in 2011. Open radical nephrectomy decreased by 33%, while minimally invasive radical nephrectomy increased by 15%. Robot-assisted laparoscopic partial nephrectomy increased from 2008 to 2011, attaining a 14% rate at university and 10% at nonuniversity hospitals (p = 0.03). It was associated with increased partial nephrectomy (OR 9.67, p <0.001). Younger age, male gender and low patient complexity predicted partial nephrectomy on overall analysis, while higher hospital volume and university status were predictors only in earlier years. CONCLUSIONS Partial nephrectomy use increased in Maryland from 2001 to 2011, which was facilitated by robotic technology. Associations with hospital factors decreased with time. These data suggest that robotic technology may enable surgeons across practice settings to more frequently perform nephron sparing surgery.

PROSTATE BIOPSY: INDICATIONS AND TECHNIQUE

PURPOSE The last decade has seen numerous modifications in the way prostate cancer is diagnosed. We review the current indications for and methods of prostate biopsy. MATERIALS AND METHODS The English language literature was reviewed regarding major indications for and methods of prostate biopsy. Pertinent peer reviewed articles were collated and analyzed. RESULTS The most widely accepted indication for prostate biopsy is a prostate specific antigen (PSA) value of greater than 4.0 ng./ml. However, some investigators advocate prostate biopsy for men with a PSA value in the 2.5 to 4.0 ng./ml. range, believing that use of this parameter results in detection of a greater number of cases of curable disease. Age specific PSA range, percent free PSA and presence of prostatic intraepithelial neoplasia or atypia are all considered to be relative indications for prostate biopsy. The current literature describes a trend toward increasing the number of cores obtained and the sites biopsied beyond those of the standard sextant technique. The additional cores in many series are obtained from more lateral regions of the gland. CONCLUSIONS Although several criteria are used as indications for initial prostate biopsy, all are based on PSA level and/or abnormal digital rectal examination. Future improvements in currently used prostate cancer markers may result in better selection of cases to biopsy. There is no universally accepted technique of prostate gland biopsy. The current literature supports use of more extensive biopsy techniques to increase the likelihood of prostate cancer detection.

Phase II Trial of Radio Frequency Ablation of Renal Cancer: Evaluation of the Kill Zone

PURPOSE We report on the pathological evaluation of renal tumors after intraoperative radio frequency ablation performed immediately before surgical nephrectomy. MATERIALS AND METHODS Ten patients with renal tumors were enrolled in a prospective, Institutional Review Board approved phase II trial of radio frequency ablation. Following surgical exposure of the kidney a single 12-minute radio frequency ablation of the tumor was performed using the Radionics Cool-tip RF Radio Frequency Ablation System (Radionics, Burlington, Massachusetts). The tumor was then excised via radical or partial nephrectomy. Gross and histological evaluations of the tumor were performed, including evaluation with nicotinamide adenine dinucleotide vital staining. RESULTS All 10 tumors were confirmed histologically to be renal cell carcinoma. Mean tumor size was 3.2 cm. (range 1.4 to 8.0). Of the 10 tumors 8 were completely ablated with a mean treatment margin of 6.75 mm. (range 2 to 13). Of the 2 tumors that were incompletely treated 1 never attained a temperature sufficient for tissue destruction and the other measured 8 cm., far exceeding the expected ablation volume of treatment protocol. CONCLUSIONS This study represents the initial report of the histological outcome of saline cooled radio frequency ablation of renal tumors. Our data indicate that it can completely destroy renal cancers while transmitting minimal collateral damage to surrounding renal parenchyma. Further investigation is required to determine long-term oncological outcome.

Effect of gastric bypass surgery on kidney stone disease.

PURPOSE Recent studies have demonstrated that mineral and electrolyte abnormalities develop in patients who undergo bariatric surgery. While it is known that these abnormalities are a risk factor for urolithiasis, the prevalence of stone disease after bariatric surgery is unknown. We evaluated the likelihood of being diagnosed with or treated for an upper urinary tract calculus following Roux-en-Y gastric bypass surgery. MATERIALS AND METHODS We identified 4,639 patients who underwent Roux-en-Y gastric bypass surgery and a control group of 4,639 obese patients who did not have surgery in a national private insurance claims database in a 5-year period (2002 to 2006). All patients had at least 3 years of continuous claims data. Our 2 primary outcomes were the diagnosis and the surgical treatment of a urinary calculus. RESULTS After Roux-en-Y gastric bypass surgery 7.65% (355 of 4,639) of patients were diagnosed with urolithiasis compared to 4.63% (215 of 4,639) of obese patients in the control group (p <0.0001). Subjects in the treatment cohort more commonly underwent shock wave lithotripsy (81 [1.75%] vs 19 [0.41%], p <0.0001) and ureteroscopy (98 [2.11%] vs 27 [0.58%], p <0.0001). Logistic regression demonstrated that Roux-en-Y gastric bypass surgery was a significant predictor of being diagnosed with a urinary calculus (OR 1.71, CI 1.44-2.04) as well as undergoing a surgical procedure (OR 3.65, CI 2.60-5.14). CONCLUSIONS Roux-en-Y gastric bypass surgery is associated with an increased risk of kidney stone disease and kidney stone surgery in the postoperative period. Clinicians should be aware of this hazard and inform patients of this potential complication. Future studies are needed to evaluate preventive measures in the high risk population.

Dual Source Computed Tomography: A Novel Technique to Determine Stone Composition

INTRODUCTION Dual source computed tomography (CT), a novel technology that employs two different x-ray sources, may provide an image resolution that has not been possible with conventional single source CT. We tested the ability of dual source CT imaging to distinguish calcium oxalate (CaOx) stones from calcium phosphate (CaP) stones, and both types of calciferous stones from uric acid (UA) stones. METHODS CaOx, CaP, and UA stones were placed in a tissue phantom and imaged with dual source multidetector CT at both 80kV and 140 kV. Hounsfield units (HU) of each stone were recorded for the 140 kV and the 80 kV datasets by drawing regions of interest by circle, hand-drawing, and using a volume calculation method. The differences between, and the ratios of, the HU obtained by the two energy sources were compared among the stone groups. RESULTS Between CaOx and CaP stones, HU differences (80kV-140kV difference, hand-drawing technique: CaOx = 270.7; CaP = 369.5; UA = 11.45; P = 0.020 for CaOx vs. CaP; P < 0.001 for CaOx and CaP vs. UA) as well as ratios (140kV:80kV ratio, hand-drawing technique: CaOx = 1.44; CaP = 1.51; UA = 1.04; P = 0.001 for CaOx vs. CaP; P < 0.001 for CaOx and CaP vs. UA) were significantly different. There were no significant differences in stone size among the groups. CONCLUSIONS Dual source CT has the ability to distinguish not only between calciferous stones and uric acid stones, but also among stones composed of different calcium salts. Further studies are warranted to confirm these findings in a clinical setting.

Changing indications of open stone surgery

OBJECTIVES To compare the current role of open stone surgery at our institution to previously reported data. In 1989, the indications for open surgical treatment of urinary calculi at our institution were reviewed. In the intervening years, tremendous advances have been made in minimally invasive treatment of urinary calculi. METHODS A retrospective evaluation of all patients undergoing procedures for the purpose of stone removal or fragmentation at Wake Forest University Baptist Medical Center between January 1, 1998 and May 31, 2001 was conducted. This was compared with data reported from our institution describing similar procedures in the first 19 months after introduction of the Dornier HM3 lithotriptor. RESULTS Of 986 procedures performed for the purpose of stone removal or fragmentation between January 1, 1998 and May 31, 2001, 0.7% were open surgical procedures. Of these procedures, 85.8% were performed for anatomic indications. Patients referred from other institutions for evaluation after endoscopic treatment failure comprised the remaining 14.2% of this group. In the previously reported data, 893 procedures were performed for the treatment of urinary calculi, of which 4.1% were open operations. Of these patients, 48.6% underwent an open surgical procedure after unsuccessful endoscopic treatment of urinary calculi, and 48.7% of these patients underwent open surgery for anatomic indications. CONCLUSIONS Open surgical stone removal remains a viable treatment option for select patients. Technologic advances and improved surgical skills have greatly reduced the number of patients requiring open surgery. This approach is mainly used for patients with complex calculous disease associated with anatomic abnormalities.

The Safety of Ureteroscopy During Pregnancy: A Systematic Review and Meta-Analysis

PURPOSE We performed a literature review and analysis to compare the safety of ureteroscopic stone removal during pregnancy with findings from a set of contemporary studies of that procedure in nonpregnant patients. MATERIALS AND METHODS A systematic review of MEDLINE(R) and EMBASE(R) was done to identify all reports of ureteroscopic stone removal in pregnant women. Complications were stratified according to modified Clavien criteria. We then reviewed a contemporary, multi-national meta-analysis of ureteroscopic stone removal (American Urological Association/European Association of Urology 2007 Guideline for the Management of Ureteral Calculi) to define the complication rate in a series of nonpregnant patients. Complication rates in the 2 reviews were compared using Fishers exact test. RESULTS A total of 14 reports of ureteroscopic stone removal in pregnant women were identified, representing 108 patients. Nine complications were noted. By Clavien criteria 2 complications were level 1, 6 were level 2 and 1 was level 3. When compared to the multinational meta-analysis of ureteroscopy in nonpregnant women, there was no significant difference in the ureteral injury and urinary tract infection complication rates (p = 0.191 and 0.597, respectively). CONCLUSIONS Our analysis shows that the safety of ureteroscopic stone removal in pregnant patients is not significantly different from the safety of that procedure in nonpregnant patients and in each cohort the complication rate is low. Therefore, ureteroscopic stone removal may reasonably be considered appropriate first line therapy in pregnant patients with stone disease.

Results of the 5 region prostate biopsy method : The repeat biopsy population

PURPOSE The decision to repeat prostate biopsy in a patient in whom the first biopsy did not detect prostate cancer poses a challenge to urologists. Many published series show a low yield on repeat biopsy using standard techniques. We reviewed our data on the 5 region prostate biopsy method to evaluate its yield in the repeat biopsy population. MATERIALS AND METHODS A total of 125 repeat transrectal ultrasound guided prostate needle biopsy sessions were done in 110 patients for standard indications using the 5 region method. Pathological findings were reviewed and the yield of the additional regions was analyzed. RESULTS Patients were categorized with respect to the initial biopsy technique. In those who underwent 1 and more than 1 previous sextant biopsy the relative increase in yield of the 5 region technique over the standard sextant technique was 31% and 33%, respectively. In the cohort that underwent previous 5 region biopsy the relative increase in yield of the 5 region technique over the standard sextant technique was 38%. CONCLUSIONS In the setting of repeat biopsy the 5 region method results in an increased yield over the sextant method. It is true in patients who have previously undergone biopsies with the sextant or 5 region technique.

Holmium laser enucleation of the prostate for prostates of >125 mL

To examine a group of patients treated with holmium laser enucleation of the prostate (HoLEP) and with the bladder outlet obstructed by an exceptionally large (>125 mL) prostate, as such men are often not considered candidates for endoscopic treatments and historically have required open surgery.

The association of increasing body mass index and kidney stone disease.

PURPOSE Previous epidemiological works have reported that obesity is a risk factor for kidney stone disease. However, the effect of increasing degrees of obesity on stone formation has yet to be defined. To address this question we examined how an increasing body mass index affects the risk of kidney stone disease. MATERIALS AND METHODS We evaluated claims from a 5-year period (2002 to 2006) in a national private insurance database to identify subjects diagnosed with or treated for kidney stones. From a data set of 95,598 patients, subjects were identified by ICD-9 or CPT codes specific to kidney stone disease. Descriptive analyses were performed and odds ratios were calculated. RESULTS Gender distribution of the 3,257 stone formers was 42.9% male and 57.1% female. Obesity (body mass index greater than 30 kg/m(2)) was associated with a significantly greater likelihood of being diagnosed with a kidney stone. However, when obese patients were stratified by body mass index there were no significant differences in the likelihood of a kidney stone diagnosis, suggesting a stabilization of risk once body mass index increased above 30 kg/m(2). The association of body mass index and a stone removal procedure was significant only for men and women with a body mass index between 30 and 45 kg/m(2) relative to a body mass index less than 25 kg/m(2) (p <0.001). CONCLUSIONS An obese body mass index is associated with an increased risk of kidney stone disease. However, the magnitude of this risk appears to be stable in the morbidly obese population. Once body mass index is greater than 30 kg/m(2), further increases do not appear to significantly increase the risk of stone disease.