Biomedical subjects

Gyan Pareek

Publications and source records attributed to Gyan Pareek.

13 recordsLinked to original sources

PubMed2006

Examination of laparoscopic retrieval bag washings for malignant cells after hand-assisted laparoscopic radical nephrectomy and intact specimen removal.

OBJECTIVES: Port site metastases after hand-assisted laparoscopic radical nephrectomy have been described in the literature. There is no uniform agreement among urologists regarding the use of a retrieval bag before intact specimen removal. The aim of this study was to determine whether LapSac renal extraction bag washings contain malignant cells. METHODS: We prospectively obtained washings from the LapSac retrieval bag after hand-assisted laparoscopic radical nephrectomy and intact specimen removal for renal cell carcinoma. In 30 consecutive cases, after removal of the kidney specimen from the LapSac, the LapSac was irrigated with 50 mL sterile Hank's balanced salt solution. These washings were sent for cytologic examination. Cytologic evaluation was performed with a Thin Prep and the Papanicolaou method. RESULTS: We performed 30 hand-assisted laparoscopic radical nephrectomies for suspected renal cell carcinoma with the above protocol. One specimen was benign and one showed transitional cell carcinoma; these were excluded from the study. Six specimens were stage T1a, 17 were T1b, 1 was T2, 2 were T3a, and 2 were T3b. Histopathology revealed 27 specimens with clear cell renal cell carcinomas with Fuhrman grades from 1 to 4; 1 specimen showed chromophobe renal cell carcinoma. Margins were negative in all cases, and there were no gross or microscopic tumor violations. The cytologic results from 27 cases were negative and in 1 case with T3b renal cell carcinoma the LapSac washings were positive for malignant cells. CONCLUSIONS: The preliminary findings from our study show that low-stage, low-grade tumors removed laparoscopically with minimal manipulation do not exfoliate cells into their LapSac retrieval bags.

Carcinoma, Renal Cell↗

PubMed2006

Meta-analysis of the complications of laparoscopic renal surgery: comparison of procedures and techniques.

PURPOSE: We performed a meta-analysis of the literature to define the current expectations of complications during laparoscopic renal surgery. MATERIALS AND METHODS: References were searched in the MEDLINE database from 1995 to 2004 using the terms complications and laparoscopic nephrectomy. Inclusion criteria were any series with greater than 20 cases, patient age older than 16 years and any complications listed for certain procedures, including laparoscopic radical nephrectomy, HA laparoscopic radical nephrectomy, LPN, HALPN, laparoscopic donor nephrectomy, HA laparoscopic donor nephrectomy, laparoscopic simple nephrectomy, laparoscopic nephroureterectomy and retroperitoneal laparoscopic nephrectomy. A data extraction form was created to categorize major or minor complications. A 5 member panel adhered to the strict criteria and extracted data from articles that met inclusion criteria. Data were entered into a spreadsheet and a meta-analysis was performed. RESULTS: Initial review identified 73 of 405 references that were acceptable for retrieval and data extraction, of which 56 met inclusion criteria. The overall major and minor complication rates of laparoscopic renal surgery were 9.5% and 1.9%, respectively. There was a significant difference between the major complication rates of LPN and HALPN (21.0% vs 3.3%, p <0.05). CONCLUSIONS: Our results show that patients who undergo laparoscopic renal surgery may have an overall major complication rate of 9.5%. The highest major complication rate is associated with technically challenging LPN (21%). There appears to be a significantly higher wound complication rate associated with HA surgery in comparison to that of standard laparoscopy (1.9% vs 0.2%, p <0.05).

Humans↗

PubMed2006

Elastographic measurements of in-vivo radiofrequency ablation lesions of the kidney.

BACKGROUND AND PURPOSE: Elastography may prove useful for monitoring radiofrequency ablative (RFA) therapy because heat-ablated tissues are more elastic than untreated tissues. Herein, we report our initial evaluations of the reliability of elastography for delineating thermal-lesion boundaries at the time of RFA of porcine kidneys. MATERIALS AND METHODS: In-vivo RFA was performed on 20 kidneys from 10 40-kg female pigs. Elastography was performed at the time of surgery and after 48 hours. The imaging plane was perpendicular to the axis of the RF electrode so that the ablated region was around the center of the plane. Measurements of the sections representing the same image plane used for elastography were taken at pathologic examination and compared with the measurements obtained from the elastograms. RESULTS: We found a statistically significant correlation between elastography and pathology measurements with respect to the area and volume estimates (r = 0.9302 and r = 0.953, respectively). Overall, elastography slightly underestimated the lesion size, as judged by the digitalized pathologic images, a finding consistent with previous reports. CONCLUSION: We found a correlation between the area and volume estimates of thermal lesions that were based on elastographic images and the measurements from gross pathologic dimensions. A significant limitation of renal RFA is the inaccuracy of current imaging modalities to provide real-time monitoring, and elastography may prove to be reliable for delineating the resulting thermal lesions.

Animals↗

PubMed2005

Extracorporeal shock wave lithotripsy success based on body mass index and Hounsfield units.

OBJECTIVES: To determine whether body mass index (BMI) and Hounsfield units (HUs) could be used as independent predictors of stone-free status after extracorporeal shock wave lithotripsy (ESWL). No detailed studies have assessed BMI as an independent predictor of ESWL outcome. Some studies have suggested that HUs of urinary calculi on noncontrast computed tomography may predict the stone-free rate after ESWL. METHODS: We evaluated 100 patients who had undergone ESWL for 5-mm to 10-mm upper urinary tract stones. The BMI was calculated for each patient. HU determination and chemical analysis was performed for each stone. Radiographic assessment at 6 weeks categorized patients into a stone-free (SF) or residual-stone (RS) group. Statistical analysis, using BMI and HUs as predictors, was performed to assess the stone-free rate after ESWL. RESULTS: Of 100 patients, 72 were in the SF and 28 in the RS group. The mean BMI for the SF group was 26.9 +/- 0.5 versus 30.8 +/- 0.9 in the RS group (P <0.05). The difference in the mean HU values for the SF and RS groups was statistically significant (577.8 +/- 182.5 versus 910.4 +/- 190.2, respectively; P <0.05). A successful outcome was significantly related to BMI (odds ratio 1.34, 95% confidence interval 1.09 to 1.65, P <0.01) and HUs (odds ratio 1.01, 95% confidence interval 1.007 to 1.019, P <0.01). The following equation was formulated to compute the probability of treatment failure: 1/1 + 2.7(-z), where z = 0.294 BMI + 0.13 HU - 18.98. CONCLUSIONS: BMI and HUs were statistically significant independent predictors of stone-free rates after ESWL. We believe a predictive model of ESWL outcome may be formulated on the basis of these findings and may be used to select the preferred treatment option for patients with urinary calculi.

Adult↗

PubMed2005

Survey from skills-based hands on learning courses demonstrates increased laparoscopic caseload and clinical laparoscopic suturing.

OBJECTIVES: To evaluate the impact of the American Urological Association Hands on Laparoscopy course on the participants' practices. Many urologists without fellowship training perform laparoscopy, but do not advance beyond hand-assisted, extirpative laparoscopy. The American Urological Association Hands on Laparoscopy course was designed to help these practitioners advance their skills. METHODS: A total of 68 urologists, aged 31 to 61 years (mean 46.6), participated in one of the four courses given between August 2002 and March 2004. The 2-day course included performing standardized tasks under videotape analysis and participating in porcine and pelvic trainer laboratory sessions. Surveys were sent by regular and electronic mail in September 2004 to assess the courses' impact. The mean follow-up was 15.2 months (range 7 to 25). RESULTS: Of the 68 surveys mailed, 54 were returned (79%). Most respondents were in private practice and had had prior experience with extirpative laparoscopy. Of the respondents, 41 (76%) reported that their laparoscopic practice had expanded after taking the course, with 34% performing at least 2 cases per month. Also, 33 respondents (61%) reported performing laparoscopic suturing after taking the course, with 35% having sutured a bleeding vessel. Of the respondents, 85% reported that the video mentoring during the course was helpful. Of those who purchased a pelvic trainer, 90% reported practicing on it regularly. CONCLUSIONS: The Hands on Laparoscopy course appeared to contribute to expansion of laparoscopic practices. Experience gained from skills-based lectures, videotape analysis of pelvic trainer performance, and a mentored porcine laboratory resulted in most (61%) participants expanding their practice to include clinical laparoscopic suturing.

Adult↗

PubMed2005

Shock wave lithotripsy success determined by skin-to-stone distance on computed tomography.

OBJECTIVES: To evaluate whether the skin-to-stone distance (SSD), body mass index (BMI), and Hounsfield unit (HU) density can be used as independent predictors of stone-free (SF) status after shock wave lithotripsy (SWL) of lower pole kidney stones. No studies have evaluated the SSD by non-contrast-enhanced computed tomography (NCCT) as a predictor of SWL success. Studies have suggested that the BMI and HU density of urinary calculi on NCCT may predict the SF rate after SWL. METHODS: The radiographs of 64 patients treated with SWL (DoliS lithotripter) from March 2000 to April 2004 with lower pole kidney stones measuring 0.5 to 1.5 cm on NCCT were reviewed. The average SSD was calculated by measuring three distances from the center of the stone to the skin (0 degrees, 45 degrees, and 90 degrees angles) on NCCT. The BMI and HU density were determined, and chemical analysis was performed on all stones. Radiographic assessment of the kidneys, ureter, and bladder at 6 weeks categorized patients into the SF or residual stone group. Logistic regression was fit, using SSD, BMI, and HU density as predictors, to assess the SF rates after SWL. RESULTS: Of 64 patients, 30 were SF and 34 had residual stones. The mean SSD was 8.12 +/- 1.74 cm for the SF group versus 11.53 +/- 1.89 cm for the residual stone group (P <0.01). Logistic regression analysis revealed only SSD to be a significant predictor of outcome (odds ratio 0.32, 95% confidence interval 0.29 to 0.35, P <0.01). An SSD greater than 10 cm predicted treatment failure. CONCLUSIONS: The SSD may predict the outcome after SWL of lower pole kidney stones. SWL in patients with an SSD greater than 10 cm is likely to fail. The use of the SSD may be transferable to the treatment of all urinary stones, regardless of location.

Female↗

PubMed2005

Urological intervention in patients with cystinuria is decreased with medical compliance.

PURPOSE: Theoretically patients with cystinuria compliant with medical treatment should undergo fewer surgical procedures than those noncompliant with treatment. We describe a single urologist's experience (SYN) with the effects of medical management on the number of surgical interventions required in patients with cystinuria treated at our metabolic stone clinic (MSC). MATERIALS AND METHODS: The records of 20 patients with cystine stones seen at our MSC (mean followup of 42.5 months) were evaluated. The number of surgical interventions (endourology or open surgery) during followup were recorded as surgical events. Patients were placed into a compliant or noncompliant category based on their attendance record at scheduled appointments at our MSC and whether they adhered to the prescribed medical regimen by report. Patients were classified in an active disease category if recent imaging revealed a clinically significant stone burden greater than 3 mm. Statistical analysis of the number of surgical events for stone-free patients compliant with treatment versus noncompliant was conducted (Student's t test). RESULTS: Of the 20 patients 11 were categorized as compliant and 9 as noncompliant. Of the compliant patients the average number of surgical events was 1.0 per patient versus 4.0 in the noncompliant group (p <0.05). Of the 11 compliant patients 8 (73%) were stone-free compared to 3 (33%) in the noncompliant group. CONCLUSIONS: The majority of our patients with cystinuria compliant with treatment underwent a significantly fewer number of surgical procedures per year than those noncompliant with treatment. Active medical management in patients with cystinuria compliant with treatment decreases the incidence of surgical interventions.

Adolescent↗

PubMed2005

Haemostatic partial nephrectomy using bipolar radiofrequency ablation.

OBJECTIVE: To determine whether an electrode array with a bipolar radiofrequency ablation (RFA) energy source can be used to perform a haemostatic partial nephrectomy by simultaneously ablating and coagulating renal tissue. MATERIALS AND METHODS: Lower-pole partial nephrectomy was performed in 12 porcine kidneys using a bipolar RFA system. Intraoperative ultrasonography was used to identify and avoid the collecting system. Tissues were positioned between opposing electrodes and tissue impedance monitored using a proprietary feedback and control algorithm. Ablation time and power, lesion width and length, and tissue thickness were recorded. The kidneys were assessed in vivo to show haemostasis of the remaining renal unit. Collecting system integrity was assessed with methylene blue injection, and the resected tissue analysed histologically. RESULTS: Partial nephrectomies were successful in all 12 porcine kidneys; the mean nephrectomy specimen was 3.2 x 2.6 cm. The total ablation time (sem) per lesion was 211 (15) s and the mean power was 23 W. Methylene blue injection showed an intact collecting system in 11 of the 12 kidneys, and haematoxylin and eosin staining showed a mean zone of necrosis of 9 mm at the resection margin. Ultrasonography revealed flow to the remaining kidneys after RFA and the in vivo assessment of haemostasis revealed no abnormal bleeding or haemorrhage from the kidneys. CONCLUSIONS: Applying bipolar RF energy to an electrode array can enable transmural excision of renal parenchyma in vivo in a bloodless fashion without collecting system injury.

Animals↗

PubMed2004

Iatrogenic bladder perforations: longterm followup of 65 patients.

BACKGROUND: We reviewed our experience with bladder perforations to better understand the causes of these injuries and to describe their management and its effect on longterm outcomes. STUDY DESIGN: Our bladder trauma database yielded 65 patients during a 12-year period, followed for a mean of 36 months, who had sustained iatrogenic bladder perforations. Endourologic procedures were excluded. Demographic data, surgical details, mechanism of injury, anatomic location, grading, diagnosis, management, and outcomes were assessed. RESULTS: Gynecologic procedures accounted for 40 perforations (61.5%), general surgical procedures for 17 (26.2%), and urologic procedures for 8 (12.3%). The type of gynecologic surgery included abdominal hysterectomy in 16 (40%), resection of a pelvic mass in 12 (30%), cesarean section in 10 (25%), and diagnostic laparoscopy in 2 (5%). Of the general surgical procedures, eight were for colon cancer (47.1%), six for diverticulitis (35.3%), and three for inflammatory bowel disease (17.6%); of the urologic injuries, six occurred during vaginal surgery and two during laparoscopy. Predisposing factors were identified in 52 patients (80%). Intraoperative urologic consultation was obtained in 63 of 65 patients, with prompt identification and repair. In two cases a concurrent left ureteral injury was identified and managed by reimplantation. The sole complication was a vesicovaginal fistula 2 months postoperatively, so the success rate for repair was 98.4%. CONCLUSIONS: Although infrequent, iatrogenic bladder perforations can occur during any pelvic, abdominal, or vaginal procedure. Prompt intraoperative recognition is paramount to ensure satisfactory outcomes. Adequate repair usually can be achieved simply by vesicorrhaphy, limiting unnecessary extravesical dissection. With this approach, morbidity can be minimized.

Colon↗

PubMed2003

The effect of finasteride on the expression of vascular endothelial growth factor and microvessel density: a possible mechanism for decreased prostatic bleeding in treated patients.

PURPOSE: Several studies have confirmed the benefit of finasteride in limiting hematuria from benign prostatic hyperplasia. Vascular endothelial growth factor (VEGF), a potent stimulator of angiogenesis, and microvessel density have been independently evaluated in the mechanism of decreased bleeding observed in patients treated with finasteride. We evaluated the expression of VEGF and suburethral prostatic microvessel density in patients with benign prostatic hyperplasia treated with finasteride. MATERIALS AND METHODS: The study included 24 patients undergoing prostatic surgery for benign disease, of whom 12 were given finasteride for a minimum of 6 weeks before surgery and the remaining 12 served as controls. Sections from the prostatic urothelium and hyperplastic prostate were individually stained for CD34 specific for nascent blood vessels and VEGF. Analysis of each specimen was performed in a blinded fashion. Microvessel density was calculated by counting the number of positively stained blood vessels on 10 consecutive, nonoverlapping, high power fields within the suburethral and hyperplastic prostate compartments. VEGF expression was examined by immunohistochemistry. Statistical analysis of the results was performed using Student's t test. RESULTS: Prostatic suburethral VEGF expression and microvessel density were significantly lower in the finasteride group compared to controls (p <0.05). Differences in VEGF expression and microvessel density at the level of the hyperplastic prostate were not found to be significantly different between the 2 groups. CONCLUSIONS Decreased expression of VEGF by finasteride inhibits angiogenesis and significantly decreases microvessel density in prostatic suburethral tissue. This sequential relationship provides histochemical insight into the mechanism by which finasteride reduces prostatic urethral bleeding.

Aged↗

PubMed2003

Hounsfield units on computerized tomography predict stone-free rates after extracorporeal shock wave lithotripsy.

PURPOSE: Studies suggest that HU values on non-contrast computerized tomography may predict the ability to fragment urinary calculi. We determined whether the HUs of in vivo urinary stones could be used to predict the stone-free rates after extracorporeal shock wave lithotripsy. MATERIALS AND METHODS: We evaluated 50 patients who underwent extracorporeal shock wave lithotripsy for 5 to 10 mm. upper urinary tract stones. Chemical analyses and HU calculations were performed for each stone and posttreatment radiographic assessment categorized patients into a stone-free or a residual stone group. Statistical analysis was performed using the Student t test to compare mean HU values in the 2 groups. RESULTS: Of the patients 32 (64%) were stone-free and 18 (36%) had residual stones. Mean values +/- SEM for the stone-free and residual stone groups were significantly different (551.20 +/- 46.66 versus 926.20 +/- 51.42 HU, p <0.0001). A total of 30 calculi (60%) were located in the ureter, including 21 in the stone-free group and 9 in the residual stone group with a mean value of 505.10 +/- 46.66 and 888.70 +/- 102.00 HU, respectively, which was significantly different (p = 0.0005). A total of 20 calculi (40%) were located in the kidney, including 11 in the stone-free group and 9 in the residual stone group with a mean value of 558.40 +/- 62.38 and 905.10 +/- 61.49 HU, respectively, which was significantly different (p = 0.001). CONCLUSIONS: These findings suggest that HU measurement of urinary calculi on pretreatment non-contrast computerized tomography may predict the stone-free rate. This information may be beneficial for selecting the preferred treatment option for patients with urinary calculi.

Female↗

PubMed2002

Decreased suburethral prostatic microvessel density in finasteride treated prostates: a possible mechanism for reduced bleeding in benign prostatic hyperplasia.

PURPOSE: We evaluated the influence of finasteride on prostatic microvessel density to elucidate a mechanism of decreased bleeding in finasteride treated patients with hematuria secondary to benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: A total of 22 patients with clinical BPH and gross hematuria who underwent prostate reductive surgery between 1998 and 2000 were prospectively evaluated. The prostate from 10 finasteride treated and 12 untreated patients was immunohistochemically stained for CD-34. Microvessel density analysis was performed by quantifying positive stained blood vessels located within the stroma of hyperplastic nodules as well as in the suburethral portion of the prostate. RESULTS: Mean microvessel density plus or minus standard deviation in finasteride treated patients was significantly lower in the suburethral portion of the prostate versus untreated controls (14.0 +/- 2.8 versus 20.2 +/- 5.3 vessels per high power field, p <0.05). In the nodular hyperplasia there was no statistically significant difference in the treatment and control groups (mean 17.5 +/- 2.8 and 16.7 +/- 4.6 vessels per high power field, respectively). CONCLUSIONS: Finasteride significantly decreases suburethral prostatic microvessel density in patients with BPH, which may explain its efficacy for decreasing BPH associated bleeding.

Aged↗

PubMedDate not supplied

The current role of cryotherapy for renal and prostate tumors.

Minimally invasive treatments continue to evolve as an alternative method for the treatment of kidney and prostatic tumors. Of the mainstream ablative procedures reported in the literature, the cryotherapy data appear to be the most durable. Currently, select kidney and prostatic lesions are treated using cryotherapy. Although limited long-term survival data using cryotherapy are available, recent series have provided compelling results, promoting interest in renal and prostatic cryoablation. This article assesses the current status of cryotherapy in urology, specifically the indications, techniques, and clinical results in treating kidney and prostate tumors.

Adult↗