Biomedical subjects

Ravi Munver

Publications and source records attributed to Ravi Munver.

28 records · Page 2Linked to original sources

PubMed2003

Practice patterns among urologic surgeons treating localized renal cell carcinoma in the laparoscopic age: technology versus oncology.

OBJECTIVES: To evaluate the effect of laparoscopy on practice patterns at a single institution in the treatment of renal cell carcinoma. Many now regard laparoscopic radical nephrectomy (LRN) as a standard of care in the management of localized renal cell carcinoma. As laparoscopy becomes more prevalent in the urologic community, practice patterns are changing. METHODS: We analyzed the renal cancer surgical database at the Weill Medical College of Cornell University from 1997 to 2002. We compared three groups, including open radical nephrectomy (ORN), open partial nephrectomy (OPN), and LRN. RESULTS: A total of 222 consecutive renal surgeries done for presumed malignancy were performed from 1997 to 2002. A total of 194 were assessable. Of these, 63 were OPNs, 51 were ORNs, and 80 were LRNs. When analyzed over time, during the latter half of 2000, 89% of all LRNs were performed on tumors less than 4 cm in size. More recently, in 2002, only 42% of LRNs were performed for tumors 4 cm or less in size. From 1997 to 2000, 30% of all OPNs were done on tumors greater than 4 cm compared with 28% from 2000 to 2002. Of 30 OPNs performed from 1997 to 2000, 21 (70%) were performed on small (4 cm or less) tumors compared with 24 (73%) of 33 from 2000 to 2002. CONCLUSIONS: From 2000 to 2002, the percentage of tumors less than 4 cm that were treated with LRN has increased with time. In the ORN cohort, the percentage of nephrectomies performed on small tumors (less than 4 cm) has decreased with time, and the trends in the OPN group have remained relatively stable. As an institution becomes more comfortable with laparoscopic techniques, technological concerns are likely to play less of a role in determining treatment algorithms among treating urologists.

Aged↗

PubMed2003

Shock wave lithotripsy causes ipsilateral renal injury remote from the focal point: the role of regional vasoconstriction.

PURPOSE: Shock wave lithotripsy induced renal damage can occur as a result of multiple mechanisms, including small vessel injury and free radical production. Previous studies have demonstrated that shock wave lithotripsy exerts a regional change in renal hemodynamics, resulting in a global reduction in the glomerular filtration rate and renal plasma blood flow. We determined if biochemical evidence of cellular damage could be identified in ipsilateral locations remote from the shock wave site or in the contralateral kidney, suggesting regional or systemic alterations in renal function. MATERIALS AND METHODS: Ten juvenile female swine underwent open insertion of microdialysis probes into the renal parenchyma at the right upper and lower poles, and left lower pole. The animals were divided evenly into a sham and a treatment group. Dialysate samples were collected from all 3 sites from the sham group at 10-minute intervals for 100 minutes and quantitatively assessed for conjugated dienes, a measure of lipid peroxidation and free-radical activity, signifying renal cellular damage. The animals in the treatment group underwent shock wave lithotripsy focused on the right lower pole. Dialysate samples were collected from all 3 sites at baseline and at 1,000 shock intervals for a total of 10,000 shocks and analyzed for conjugated dienes. The results from the sham and treatment groups as well as from the different locations within each group were compared using Student's t test. RESULTS: The mean conjugated diene ratio for the sham group was 3.59, 3.42 and 2.7 microM. for the right upper and lower poles, and left kidney (p >0.05). A dose related increase in conjugated diene ratio levels from the right lower pole (lithotripsy site) and to a lesser degree from the ipsilateral right upper pole were observed, which were significantly different from sham group measurements or the contralateral kidney of the treatment group (p <0.05). The elevation in conjugated diene levels at the lithotripsy site was also noted to be significantly greater than that of the upper pole of the ipsilateral kidney (p <0.05). CONCLUSIONS: The increase in free radical activity at a site remote from the treated region suggests detrimental global effects from shock wave lithotripsy therapy. These observations could be the result of vasoconstriction throughout the treated kidney with resultant ischemia-reperfusion injury. Although these global renal effects may subject patients with baseline renal dysfunction to irreversible renal damage, the clinical significance of our findings is unclear and warrants further investigation.

Animals↗

PubMed2003

Minimally invasive surgical management of ureteropelvic junction obstruction: laparoscopic and robot-assisted laparoscopic pyeloplasty.

Ureteropelvic junction (UPJ) obstruction is characterized by a functionally significant impairment of urinary transport caused by an intrinsic or extrinsic obstruction in the area where the ureter joins the renal pelvis. The majority of cases are congenital in origin; however, acquired conditions at the level of the ureteropelvic junction may also present with symptoms and signs of obstruction. Until recently, open pyeloplasty and endoscopic techniques have been the main surgical options, with the intent of complete excision or incision of the obstruction. The introduction of laparoscopy and robot-assisted applications has allowed for minimally invasive reconstructive surgery that mirrors open surgical techniques. These techniques offer substantial benefits to patients by reducing morbidity, hastening postoperative recovery, and improving cosmetic outcome. During the last decade, laparoscopic pyeloplasty has garnered much interest. However, because of the technically challenging nature of this procedure, it is performed only at select medical centers by surgeons with advanced laparoscopic training. The recent introduction of robotics to the field of minimally invasive surgery may facilitate this procedure and allow for more widespread implementation by surgeons of varying skill levels. This review is limited primarily to the treatment of congenital or acquired UPJ obstruction via laparoscopic and robot-assisted laparoscopic pyeloplasty. Herein, we report the early results, ongoing evolution, and potential future role for these novel surgical procedures.

Humans↗

PubMed2002

Hypertonic saline-augmented radiofrequency ablation of the VX-2 tumor implanted in the rabbit kidney: a short-term survival pilot study.

OBJECTIVES: The increased incidental detection of small (less than 4 cm) renal tumors has stimulated investigations of minimally invasive therapies. Radiofrequency energy is a relatively new and evolving technology that has been used for a variety of experimental and clinical applications. We evaluate the efficacy of hypertonic interstitial saline-augmented radiofrequency therapy to ablate a malignant VX-2 tumor implanted in a rabbit kidney, as measured by the completeness of tumor destruction and progression to metastasis. METHODS: The VX-2 tumor was surgically implanted into the left lower pole parenchyma of 18 New Zealand white rabbit kidneys. Ten days after implantation, hypertonic interstitial saline-augmented radiofrequency ablation was performed (n = 12) using a radiofrequency therapy system (RFT, United States Surgical Corp.). A sham operation was performed on a control group (n = 6). Animals were humanely killed at 5, 10, and 15-day intervals, and the clinical response and effect of radiofrequency energy on the malignant renal tissue was assessed. RESULTS: No postoperative complications were encountered. The mean size of the implanted VX-2 tumor was 1.87 cm2. Kidneys in the treated group exhibited marked destruction of tumor tissue. Histologic analysis revealed coagulative necrosis of both malignant and normal renal tissue in the treated group. Three rabbits (1 control, 2 treated) died of metastatic disease. CONCLUSIONS: Coagulative necrosis of renal parenchyma and tumor tissue was clearly demonstrated after radiofrequency ablation using the RFT system. The aggressive growth pattern of the VX-2 tumor often resulted in progression to metastatic disease while precluding complete tumor ablation. Hypertonic saline-augmented radiofrequency ablation is a promising new technology for the management of small, locally confined, renal tumors and has the potential for use with a minimally invasive approach.

Animals↗

PubMed2002

Endoscopic management of symptomatic caliceal diverticula: a retrospective comparison of percutaneous nephrolithotripsy and ureteroscopy.

BACKGROUND AND PURPOSE: A myriad of minimally invasive options exist for managing symptomatic caliceal diverticula, including shockwave lithotripsy, percutaneous surgery, retrograde ureteroscopy, and laparoscopy. Yet no direct comparisons have been made in the literature of the relative treatment efficacy of ureteroscopy (URS) and percutaneous nephrolithotripsy (PNL). A retrospective review of our patients was performed to determine the most appropriate endoscopic management option for patients with symptomatic caliceal diverticula. PATIENTS AND METHODS: Between November of 1994 and April 2001, 39 patients presented with symptomatic caliceal diverticula, 37 of which contained calculi. Twenty-two patients (56%) underwent PNL, and 17 patients (44%) were managed by URS. Of the PNL group, 82% required the creation of a neoinfundibulotomy. The stone burden in the PNL group averaged 11.4 x 12.0 mm and that in the URS group 12.7 x 13.0 mm (p > 0.05). Pain, recurrent urinary tract infections, and nausea and vomiting were the presenting complaints in both subgroups of patients, with pain being by far the most common symptom. The average hospital stay was 2.8 days for the PNL group. All the URS procedures were performed on a same-day-surgery basis. Results, including stone-free, symptom-free, and complication rates, were compared for the two groups. RESULTS: Thirty-five percent of the URS group were symptom free at 6 weeks' follow-up, with an additional 29% reporting an improvement in pain, whereas 86% of the PNL group was completely symptom free at 6 weeks' follow-up. Only 19% of the URS group were stone free on follow-up intravenous urography v 78% of those undergoing PNL (three patients failed to return for follow-up imaging). It was not possible to identify the ostium of the stenotic infundibulum in 4 patients (24%) undergoing URS, and 7 patients (41%) eventually went on to PNL with ultimate success. The PNL was statistically better than URS in producing stone-free results for diverticula located in the upper pole and for stones <11 mm (p < 0.05). No complications occurred in the URS group; however, complications were identified in four patients after PNL. One patient developed clot urinary retention necessitating Foley catheterization and manual bladder irrigation; one patient experienced significant bleeding necessitating early cessation of the procedure. Two patients sustained intrathoracic complications, one a pneumothorax and the other a pneumohemothorax after supra-11(th) rib access. Both were managed successfully with tube thoracostomy. CONCLUSIONS: Our review clearly suggests an advantage of percutaneous management over ureteroscopy for complex posterior symptomatic caliceal diverticula, although with a slightly increased risk of complications. Therefore, PNL should be considered the primary modality for managing these difficult processes. In cases where the stenotic infundibulum cannot be traversed with a guidewire, creation of a neoinfundibulotomy permitted secure access to the collecting system while providing effective results.

Adolescent↗

PubMed2002

Routine ureteral stenting is not necessary after ureteroscopy and ureteropyeloscopy: a randomized trial.

BACKGROUND AND PURPOSE: Retrospective studies have suggested that routine stenting can be avoided following ureteroscopy. We prospectively analyzed the need for routine ureteral stent placement in patients undergoing ureteroscopic procedures. PATIENTS AND METHODS: Fifty-five consecutive patients (60 renal units) were randomized into either a stent or a no-stent group following ureteroscopy with either a 7.5F semirigid or a 7.5F flexible ureteroscope for treatment of calculi (holmium laser or pneumatic lithotripsy) or transitional-cell carcinoma (holmium laser). Intraoperative variables assessed included total stone burden, the need for ureteral dilation, and overall operative times. All patients were evaluated by questionnaire on postoperative days 0, 1, and 6 with regard to pain, frequency, urgency, dysuria, and hematuria. RESULTS: Of the 60 renal units treated, 38 received ureteral stents (mean 5.2 days), and 22 were treated without a stent. All 10 patients requiring ureteral balloon dilation had stents placed and were removed from the analysis. There was no significant difference between the groups with regard to age, sex, or stone burden. Operative time was decreased in the no-stent group (43 minutes v 55 minutes; P = 0.013). Flank discomfort was significantly less common in the no-stent group on days 0, 1, and 6 (P = 0.004, P = 0.003, P < 0.001, respectively), as was the incidence of suprapubic pain on day 6 (P = 0.002). There was no difference in urinary frequency, urgency, or dysuria between the groups on postoperative day 1, but all these symptoms were significantly reduced in the no-stent group on day 6 (P < 0.001, P < 0.001, P = 0.002, respectively). There was no significant difference in patient-reported postoperative hematuria in either group. One patient in each group developed a urinary tract infection. One patient in the no-stent group developed ureteral obstruction in the postoperative period that necessitated stenting, and one patient in the stent group experienced stent migration necessitating removal. CONCLUSIONS: Routine ureteral stenting does not appear to be warranted in those patients who do not require ureteral dilation during ureteroscopic procedures. Ureteral stent placement following ureteroscopy may be avoided, thereby reducing operative time, surgical costs, and patient morbidity.

Adult↗

PubMed2002

In vivo assessment of free radical activity during shock wave lithotripsy using a microdialysis system: the renoprotective action of allopurinol.

PURPOSE: Shock wave lithotripsy is believed to cause renal damage directly through cellular injury from high energy shock waves and indirectly through vascular injury and resultant ischemia, which gives rise to oxygen free radical compounds. The transient and volatile nature of free radicals and derived products makes their detection difficult. Moreover, certain medications may provide a protective effect against shock wave lithotripsy induced renal parenchymal injury. We introduced an innovative microdialysis system for in vivo sampling of interstitial fluids that can be analyzed for free radical mediated lipid peroxidation products after shock wave lithotripsy treatment in the swine model. In addition, this system was used to test the antioxidant or renoprotective action of allopurinol. MATERIALS AND METHODS: Ten juvenile swine were assigned to a nonmedicated control group that underwent shock wave lithotripsy or to a group that was premedicated with allopurinol before shock wave lithotripsy. Each group of animals underwent shock wave lithotripsy to the lower pole of the right kidney and received a total of 10,000 shock waves. Dialysate fluid was collected at 1,000-shock wave increments via probes surgically implanted into the lower pole of the right and left kidneys before lithotripsy. Samples were immediately preserved in liquid nitrogen and subsequently analyzed for the presence and concentration of conjugated diene levels, a measure of lipid peroxidation. Five additional juvenile swine were assigned to a sham treated group that did not undergo shock wave lithotripsy. Dialysate fluid was collected from the lower pole of the right and left kidneys to establish baseline or pre-lithotripsy levels of conjugated dienes. RESULTS: After shock wave lithotripsy conjugated diene levels increased almost 100-fold over that in the right kidneys of the nonmedicated control group. The difference was statistically significant compared to levels in the contralateral untreated kidneys (p <0.01). Right kidneys in the group premedicated with allopurinol did not demonstrate an increase in conjugated diene levels during shock wave lithotripsy. CONCLUSIONS: The results of this study confirm shock wave lithotripsy induced free radical activity as well the antioxidant and protective nature of allopurinol. The newly described microdialysis system enables real-time sampling of interstitial fluids during shock wave lithotripsy. It represents a unique method for assessing free radical formation and evaluating the protective effects of additional antioxidant medications.

Allopurinol↗

PubMed2002

Neoinfundibulotomy for the management of symptomatic caliceal diverticula.

PURPOSE: Direct percutaneous access provides effective treatment for complex caliceal diverticula. Yet, access into the diverticulum alone is usually tenuous and passage of a guide wire across a stenotic infundibulum is often impossible. An alternative technique is described which creates a "neoinfundibulum" to assist in the management of symptomatic caliceal diverticula. MATERIALS AND METHODS: During a 6-year period 22 patients with symptomatic caliceal diverticula were treated via a percutaneous approach, of whom 21 had calculi within the diverticula. After accessing the diverticulum directly, it was impossible to pass a guide wire through the stenotic infundibulum in 18 (82%) patients, prompting advancement of the access needle through the diverticular wall into the renal pelvis. Once secure access was established, balloon dilation was performed to 30Fr to create the "neoinfundibulum." Percutaneous ultrasonic lithotripsy was performed in the usual fashion. A 22Fr Councill catheter was placed to keep the infundibular tract open for 5 to 7 days to allow complete epithelialization and drainage. Stone-free, symptom-free and complication rates were assessed. RESULTS: Pain, recurrent urinary tract infections and hematuria were the presenting complaints in the subgroup of patients undergoing "neoinfundibulotomy." Average stone burden was 11.7 x 12 mm. and average hospital stay was 2.8 days. Of the patients 94% were symptom-free at 6-week followup, and 80% were stone-free on followup excretory urography. The remaining patients had residual stone fragments less than 3 mm. in diameter. Complications related to access were identified in 2 patients who sustained a pneumothorax after a supra-11th rib access, which was successfully managed with tube thoracostomy. CONCLUSIONS: Percutaneous management of complex caliceal diverticula provides a safe and effective option for symptomatic patients. When the stenotic infundibulum cannot be traversed with a guide wire, creation of a new infundibulum offers a secure alternative for accessing the collecting system, while providing equally effective results.

Adolescent↗

PubMedDate not supplied

Robot-assisted laparoscopic dismembered pyeloplasty.

OBJECTIVE: Advanced laparoscopic skills limit the implementation of laparoscopic pyeloplasty to centers with extensive experience. The introduction of robotic technology into the field of minimally invasive surgery has facilitated complex surgical dissection and genitourinary reconstruction. We report our experience with robot-assisted laparoscopic pyeloplasty using the da Vinci Robotic Surgical System at 3 New York City medical centers. METHODS: A review of all robot-assisted laparoscopic Anderson-Hynes dismembered pyeloplasty cases in 38 patients (21 females, 17 males) between April 2001 and January 2004 was performed. All patients had symptoms or radiographic evidence of ureteropelvic junction obstruction. Robotic assistance with the da Vinci Robotic Surgical System was used after preparation of the ureteropelvic junction with a standard laparoscopic approach. RESULTS: The average patient age was 39.3 years (range, 15 to 69). The mean operative time and suturing time were 225.6+/-59.3 minutes and 64.2+/-14.6 minutes. The average estimated blood loss was minimal at 77.3+/-55.3 mL. The mean length of hospitalization was 69.6 hours (range, 28 to 310). The average use of intravenous morphine was 26.5 mg (range, 0 to 162). No intraoperative complications occurred, and open conversions were not necessary. A mean follow-up of 12.2 months revealed a success rate of 94.7% with 2/38 patients requiring further treatments. CONCLUSIONS: This combined multi-institutional series reveals that robot-assisted pyeloplasty with the da Vinci Surgical System is safe and reproducible. These intermediate results appear comparable to results with open and laparoscopic pyeloplasty repairs.

Adult↗

PubMedDate not supplied

Prospective study of quality of life of patients receiving treatment for prostate cancer.

BACKGROUND: No research was found that compared quality of life (QOL) outcomes of prostate cancer patients receiving intensity-modulated radiation therapies with prostate cancer patients receiving radical prostatectomy. OBJECTIVES: To (a) describe differences in QOL before and after three types of treatment for prostate cancer: radical prostatectomy, intensity-modulated radiation therapy + seed implantation (permanent brachytherapy), or intensity-modulated radiation therapy + high dose rate radiotherapy (temporary brachytherapy); and (b) investigate demographic, physical, and psychosocial variables that impact QOL of men with prostate cancer. METHODS: Data were collected on three occasions: baseline (prior to treatment), 1 month, and 3 months after beginning treatment. Measures included biographic data, physiological, and psychological measures. Analysis of variance and hierarchical regression were used to examine patterns, describe differences, and identify predictors of QOL in the three treatment groups. QOL was conceptualized as a multidimensional construct that included physical, psychological, social, and functional well-being and prostate cancer concerns. RESULTS: Groups differed significantly in bowel and urinary symptom scores and prostate cancer concerns at baseline, and in urinary and depressive symptoms at 3 months. There were no significant group differences at 1 month. DISCUSSION: Significant differences were found in QOL as measured with the Functional Assessment of Cancer Treatment-Prostate after treatment with radical prostatectomy, intensity-modulated radiation therapy + seed implantation, or intensity-modulated radiation therapy + high dose rate radiotherapy. Findings may provide healthcare providers with knowledge about treatment sequelae for prostate cancer, enable healthcare providers to educate patients about QOL outcomes of treatment for prostate cancer, and enable patients to make more informed treatment decisions.

Adult↗