High intensity focused ultrasound renal tissue ablation: a laparoscopic porcine model.

PURPOSE: High intensity focused ultrasound for renal lesions is still experimental. In a porcine model we evaluated the safety and efficacy of a newly designed laparoscopic high intensity focused ultrasound probe and software that allows real-time ultrasound guidance during renal tissue ablation. MATERIALS AND METHODS: A Sonatherm 600 high intensity focused ultrasound system with a newly designed laparoscopic high intensity focused ultrasound probe was used through a standard Endopath 18 mm port. A total of 16 lesions were created in 15 kidneys in a total of 8 animals and randomized into 2 groups, including acute with sacrifice 4 days postoperatively and subacute with sacrifice 14 days postoperatively. Lesion size and location varied for each surgical procedure to simulate various treatment scenarios. RESULTS: Mean +/- SD planned ablation volume was 7.1 +/- 5.1 cc and mean treatment time was 7.2 +/- 06.88 minutes. For all lesions an injury volume was observed with a central zone of complete necrosis and no viable tissue. Mean total injury volume was 6.5 + 3.5 cc (range 1.1 to 13.7), comparable to preoperative mean planned ablation volume (p = 0.84). Mean necrosis volume was 4.89 +/- 2.9 cc (range 0.8 to 10.5), appreciably lower than preoperative mean planned ablation volume (p = 0.33). Presence of the collecting system interposed with the treatment region did not impact the injury volume-to-planned ablation volume ratio or the necrosis volume-to-planned ablation volume ratio. No animals died before study completion. Two intraoperative complications occurred, including a back wall musculature burn and a ureteral burn. CONCLUSIONS: Laparoscopic high intensity focused ultrasound for renal tissue using the newly developed probe was feasible and efficacious. The ability to perform renal high intensity focused ultrasound through an 18 mm laparoscopic port offers a new alternative for renal tumor ablation.

Case report: radiofrequency ablation-induced renal-pelvic obstruction resulting in nephrectomy.

Radiofrequency ablation (RFA) has emerged as a minimally invasive nephron-sparing treatment for small (<4-cm) renal tumors. Post-RFA complications have been reported. We describe a patient who developed complete renal-pelvic obstruction after RFA. To our knowledge, this is the first such case to be reported and the second reported renal-unit loss as the result of collecting-system obstruction after RFA.

Well-differentiated papillary mesothelioma occurring in the tunica vaginalis of the testis with contralateral atypical mesothelial hyperplasia.

Well-differentiated papillary mesothelioma (WDPM) occurs rarely in the paratesticular region, with only a handful of published case reports. Often presenting with recurrent hydrocele, WDPM is a multifocal mesothelial proliferation with a predominantly indolent clinical course. Accordingly, pathologic distinction of this lesion from true malignant mesothelioma is crucial, although it may be difficult because of the variability of associated histologic features. In addition, rare cases of WDPM have progressed to malignant mesothelioma, leading to its classification as a tumor of low malignant potential. Here, we report a case of multifocal WDPM occurring in the tunica vaginalis and tunica albuginea, with contralateral atypical mesothelial hyperplasia, a potentially premalignant lesion.

Case report: Urothelial hyperplasia causing recurrent obstruction after ureteral metal stent placement in treatment of ureteroenteric anastomotic stricture.

Initial experience utilizing metal stents in the treatment of ureteroenteric anastomotic strictures has yielded promising results. However, the long-term efficacy of metal stent placement remains unknown. Further, there is a paucity of literature to describe the technical considerations associated with the surgical management of obstruction after metal stent failure. We report the case of a 67-year-old man undergoing bilateral ureteral metal stent removal and ileal conduit creation following stent failure and recurrent obstruction.

Case report: laparoscopic resection of ureteral inverted papilloma.

Inverted papilloma of the ureter is a rare entity, often mistaken for malignancy during work-up. As such, many of these patients have been unnecessarily treated with nephroureterectomy. Herein, we describe a novel laparoscopic approach for the treatment of a ureteral inverted papilloma. To our knowledge, this approach is the first application of laparoscopy for the treatment of this lesion.

The core learning objectives education model: an approach to the teaching of core concepts in the clinical clerkship.

INTRODUCTION AND OBJECTIVE: The classical approach to the undergraduate medical clerkship has several limitations, including variability of clinical exposure and method of examination. As a result, the clerkship experience does not ensure exposure to and reinforcement of the fundamental concepts of a given specialty. MATERIALS AND METHODS: This article reviews the classic approach to clerkship education within the undergraduate medical education. Specific attention is placed on clinical exposure and clerkship examination. RESULTS: We describe the introduction of the Core Learning Objective (CLO) educational model at the University of Chicago Section of Urology. This model is designed to provide an efficient exposure to and evaluation of core clerkship learning objectives. CONCLUSIONS: The CLO model has been successfully initiated, focusing on both technical and clinical skill sets. The proposed model has been introduced with positive initial results and should allow for an efficient approach to the teaching and evaluation of core objectives in clerkship education.

Long-term follow-up of single versus double cuff artificial urinary sphincter insertion for the treatment of severe postprostatectomy stress urinary incontinence.

OBJECTIVES: To assess the long-term effectiveness and complications associated with single and double cuff artificial urinary sphincter (AUS) implantation for the treatment of severe postprostatectomy stress urinary incontinence (SUI). METHODS: We updated the outcomes of 56 men with postprostatectomy SUI who underwent single (28 patients) or double (28 patients) cuff AUS placement. Originally patients in each cohort were matched according to preoperative pad usage, risk factors for complications, and age. Continence, quality of life, and complications were assessed according to the Incontinence Impact Questionnaire Short Form (IIQ-7), postoperative pad usage, chart review, and patient/family interview. RESULTS: Updated data were available for 47 men (25 single cuff and 22 double cuff patients). Mean pre-AUS implant age was 67 years for each group. Average follow-up was 74.1 months and 58.0 months for single and double cuff patients, respectively. No statistically significant difference in continence improvement was noted between the two groups according to daily pad usage and overall dry rate. IIQ-7 scores improved from 14.8 to 4.1 after single cuff implants and from 16.3 to 6.4 after double cuff placement (P = 0.34). Men receiving a single cuff AUS reported seven complications requiring further operative intervention. Double cuff patients underwent 12 additional surgeries secondary to complications. CONCLUSIONS: Despite our earlier findings, no significant difference in dry rate, overall continence, or quality of life was seen with long-term follow-up of single versus double cuff AUS patients. Furthermore, men receiving double cuff implants may be at higher risk of complications requiring additional surgery.

Analysis of impact of body mass index on outcomes of laparoscopic renal surgery.

OBJECTIVES: As the prevalence of obesity increases in the United States, it has become more important to assess its impact on surgical outcomes. We evaluated the significance of obesity on laparoscopic radical nephrectomy (LRN) and laparoscopic partial nephrectomy (LPN). METHODS: This was a prospective database study evaluating patients who underwent either LRN or LPN from October 2002 to January 2006. Patients were divided into five groups as determined by the World Health Organization body mass index (BMI) classification: less than 25.0, 25.0 to 29.9, 30.0 to 34.9, 35.0 to 39.9, and 40.0 kg/m2 or more. Demographic (age, tumor size, American Society for Anesthesiologists score), operative (estimated blood loss, operative time, open conversion), and postoperative (complications, hospital stay, margin status) data were compared. RESULTS: Of 239 patients who had undergone LRN or LPN during the study period, 146 underwent LRN and 85 underwent LPN. Of the 239 patients, 42% were obese. No statistical significance was determined for estimated blood loss, operative time, hospital stay, number of open conversions, or complications. However, a trend toward increased operative time and intraoperative complications was determined using linear and logistic regression analyses. CONCLUSIONS: Laparoscopic renal surgery is safe in overweight and obese patients and may be the surgical management of choice in this subset of patients. However, obese patients should be warned that their degree of obesity may be associated with increased difficulty of surgery as reflected by a trend toward longer operative times and more intraoperative complications.

Recovery of renal function after complete renal hilar versus artery alone clamping during open and laparoscopic surgery.

PURPOSE: It is generally accepted that simultaneous occlusion of the renal artery and vein during warm ischemia is more damaging than occlusion of the artery alone. Pneumoperitoneum during laparoscopy may impair venous backflow, negating the benefits of clamping the artery alone. We evaluated the effect of laparoscopic vs open surgery on the recovery of renal function after clamping of the renal artery and vein, and the artery alone in a solitary kidney porcine model. MATERIALS AND METHODS: Right laparoscopic nephrectomy was performed in 36 pigs. After a 12-day recovery period the animals were randomized into 3 groups, including 1) 120-minute warm ischemia with renal artery and vein occlusion, 2) 120-minute warm ischemia with artery alone occlusion and 3) control sham surgery. The groups were further subdivided into an open and a laparoscopic arm. Serum creatinine was assessed preoperatively, and on postoperative days 1, 3, 8 and 15. RESULTS: Artery alone clamping resulted in a significantly lower serum creatinine increase on postoperative days 1 and 3 in the open arm compared to the laparoscopic arm. Compared to open renal artery and vein clamping the increase in serum creatinine for open artery alone clamping was also significantly lower on postoperative days 1 and 3. No significant difference in postoperative serum creatinine was found between the laparoscopic artery alone, and the renal artery and vein arms at any time point. No significant serum creatinine changes were observed in the control sham surgery group compared to preoperative values at all followup time points. CONCLUSIONS: In this porcine model clamping of the artery alone during open surgery better protected the kidney from warm ischemia compared to renal artery and vein occlusion. This benefit was not observed during laparoscopic surgery. We speculated that the presence of pneumoperitoneum causes at least partial occlusion of the renal vein, thus, negating the benefit of renal artery clamping only.

Effect of renal ischemia in laparoscopic acute versus chronic solitary kidney model.

OBJECTIVES: The effects of renal warm ischemia (WI) in an acute versus a chronic single kidney model have not been investigated. Previously, we reported full recovery of renal function after 90 minutes of WI in a single-kidney porcine model. Here, we sought to assess the effects of WI on renal function in an acute versus chronic solitary kidney in the porcine model. METHODS: A total of 32 pigs weighing 60 to 80 lb were randomized into four groups. Group 1 (acute model) underwent nephrectomy followed by 90-minute immediate WI clamping of the contralateral renal hilum. Group 2 (control for group 1) underwent nephrectomy followed by contralateral sham renal pedicle surgery. Group 3 (chronic model) underwent nephrectomy followed 12 days later by 90-minute WI clamping of the contralateral renal hilum. Group 4 (control for group 3) underwent nephrectomy followed 12 days later by contralateral sham renal pedicle surgery. Serum creatinine and the glomerular filtration rate were assessed preoperatively and on postoperative days 1, 3, 8, and 15. All procedures were performed laparoscopically. RESULTS: The acute model showed a significantly greater increase in serum creatinine and lower glomerular filtration rate nadir compared with the chronic model on postoperative days 1, 3, and 8. By postoperative day 15, the serum creatinine and glomerular filtration rate were comparable between the acute and chronic groups after WI. CONCLUSIONS: Renal dysfunction in the acute model was significantly more profound during the initial 8 days after WI compared with that in the chronic model. These results validate our acute single kidney porcine model as a practical and cost-effective model when performing renal ischemia research.

A pilot study of ice-slurry application for inducing laparoscopic renal hypothermia.

OBJECTIVE: To assess, in a pilot study, the feasibility of delivering a microparticulate ice slurry (MPS) to provide regional hypothermia, as renal cooling during laparoscopic procedures is cumbersome and inefficient. MATERIALS AND METHODS: An ex vivo preparation was used to simulate the boundary conditions of a kidney. Four pig kidneys were placed onto a thin membrane overlying a constant temperature bath (37 degrees C) with parenchymal thermocouples. Renal surfaces were coated with MPS and temperatures recorded. In an in vivo pig model we assessed laparoscopic delivery and cooling ability of the MPS under physiological conditions. Kidneys in two pigs were laparoscopically exposed; thermocouple probes were placed throughout the kidney and the hilum was clamped. MPS was delivered through a modified 5-mm laparoscopic suction/irrigation cannula. Cortical and core body temperatures were measured. RESULTS: In the ex vivo study, the mean (sd) initial temperature was 37.1 (0.4) degrees C; the mean time to reach 15 degrees C was 10.3 (2.6) min and the mean nadir temperature was 13.0 (1.5) degrees C. In vivo, the MPS was delivered with no technical difficulty; the mean renal unit starting temperature and core body temperature were 37.2 degrees C and 37.0 degrees C, respectively. The mean (range) time to reach 15 degrees C was 16.5 (5.5-28.6) min. The mean nadir core body temperature was 34.0 degrees C. CONCLUSION: This initial study showed efficient and rapid induction of renal hypothermia using MPS delivered through 5-mm laparoscopic ports, with no technical difficulty. These exploratory pilot findings support further, larger scale, histopathological and renal functional investigations of topical ice slurries as a means of providing renal hypothermia in laparoscopic procedures.

Assessment of the LapraTy clip for facilitating reconstructive laparoscopic surgery in a porcine model.

OBJECTIVES: To assess the efficacy, reliability, and performance of the LapraTy clip (LTc) as a substitute for knot tying during reconstructive surgery in a porcine model. METHODS: Twenty-four farm pigs were divided in two groups, each undergoing two surgical procedures: group A, transperitoneal laparoscopic cavotomy and small-bowel enterotomy with repair, and group B, laparoscopic partial nephrectomy and cystotomy with repair. In all animals LTc were used to replace knot tying. Tissue specimens were harvested and examined at 2, 4, and 8 weeks postoperatively to assess success of reconstruction and tissue reaction. RESULTS: There were no major complications. Animals in group A showed no clinical signs of caval obstruction. No intraperitoneal collections or significant narrowing were noted at the enterotomy sites. Animals in group B showed no evidence of fluid collections around the partially resected kidneys or the cystotomy sites, and all repairs were intact. Pathologic examination revealed that all LTc were encapsulated by fibroblasts and giant cells typical of a foreign body-type granulomatous reaction. No evidence of clip migration into the epithelium was noted in any of the tissues examined. CONCLUSIONS: In an animal model, the LTc is a safe and efficient alternative to knot tying during laparoscopic reconstructive surgery. We are currently evaluating the clinical applicability of the LTc in a variety of urologic conditions. We believe that other surgical specialties should evaluate this device as well.

Laparoscopic ice slurry coolant for renal hypothermia.

PURPOSE: We assessed the safety and efficacy of microparticulate ice slurry for laparoscopic hypothermia during renal ischemia in a single kidney porcine model. MATERIALS AND METHODS: A total of 18 farm pigs were randomized to 3 groups of 6 each. All groups underwent initial right laparoscopic nephrectomy, followed by 1 of 3 procedures on the left kidney. Group 1 underwent 90-minute hilar clamping under warm ischemia, group 2 underwent 90-minute hilar clamping under cold ischemia using laparoscopically delivered microparticulate ice slurry and control group 3 underwent hilar dissection, no clamping and no microparticulate ice slurry. Body and renal cortical temperatures were measured. Serum creatinine and the glomerular filtration rate were assessed preoperatively, and on postoperative days 1, 3, 8 and 15. RESULTS: Average time to achieve a renal temperature of 20C or less was 9.7 minutes and it remained constant during the 90-minute cold ischemia time. Mean serum creatinine was significantly higher in the warm ischemia group than in the cold ischemia and control groups on postoperative days 1 and 3. Additionally, mean serum creatinine in the cold ischemia and control groups was similar at all time points. The mean glomerular filtration rate was significantly lower in the warm ischemia group than in the cold ischemia and control groups on postoperative days 1, 3 and 8. The mean glomerular filtration rate in the cold ischemia group was lower than in the control group on postoperative day 1, while it was similar on postoperative days 3, 8 and 15. CONCLUSIONS: In the porcine model laparoscopic renal hypothermia achieved with microparticulate ice slurry was safe and efficient. It significantly decreased renal dysfunction secondary to an ischemic insult with no adverse effects or complications associated with microparticulate ice slurry use.

Early outcomes of mid-urethral slings for female stress urinary incontinence stratified by valsalva leak point pressure.

AIMS: To assess the early results of mid-urethral slings placed via the transobturator approach (TVT-O) for stress urinary incontinence (SUI) in women with high (>60 cm H(2)O) and low (60 cm H(2)O) or low (60. CONCLUSIONS: With limited follow up, TVT-O appears to be a safe and effective surgical treatment for female SUI producing excellent results in patients with VLPP >60 cm/H(2)0. Patients with low VLPP may consider conventional, retropubic mid-urethral slings or other procedures as treatment for SUI.

Laparoscopic radical nephrectomy: comparison of clinical Stage T1 and T2 renal tumors.

OBJECTIVES: To compare the outcomes after laparoscopic radical nephrectomy (LRN) at our institution to treat Stage T1 and T2 renal tumors. LRN for Stage T1 renal tumors (less than 7 cm) has become the standard of care at many institutions. The feasibility of performing more complex LRNs on higher stage tumors is continually evolving. METHODS: A retrospective review was performed of a prospective database of patients undergoing LRN at the University of Chicago from October 2002 to January 2006. The data on 141 unilateral LRNs, 98 for clinical Stage T1 tumors and 43 for clinical Stage T2 tumors, were analyzed. The demographic, operative, and postoperative data were compared between the two groups. RESULTS: The demographic data between the two groups was comparable. Operatively, patients with larger tumors had significantly greater blood loss, a longer operative time, and a longer surgical incision. Open conversions (1% versus 12%, P = 0.013) and intraoperative complications (5% versus 19%, P = 0.006) were more likely in patients with clinical Stage T2 tumors. Most intraoperative complications were hemorrhage requiring transfusion. However, the postoperative complication rates (25% versus 21%, P = 0.646) and hospital stay (2.0 versus 2.4 days, P = 0.134) were similar between the two groups. CONCLUSIONS: In experienced centers, clinical Stage T2 renal tumors can be managed efficiently with laparoscopy. LRN for larger tumors demonstrated equivalent perioperative safety compared with LRN for smaller tumors.

Post-operative changes mimicking the radiographic appearance of recurrent renal cell carcinoma.

Partial nephrectomy for small renal tumors is associated with excellent long-term outcomes. In the absence of positive surgical margins, local recurrence is uncommon. Although computed tomography is associated with good diagnostic accuracy, the radiographic evaluation of some renal lesions remains difficult. This difficulty can be greater in the period following surgery, when post-operative tissue changes can result in abnormal radiographic findings. We report a case of benign post-operative changes mimicking the radiographic appearance of recurrent renal cell carcinoma.

A role for the P2X receptor in urinary tract physiology and in the pathophysiology of urinary dysfunction.

OBJECTIVE: We provide a historical perspective of the P2X receptor class in bladder physiology and the pathophysiology of urinary dysfunction. METHODS: A literature search was performed using the MEDLINE database. RESULTS: Evidence suggests that P2X receptors serve a combined function in sensory and motor activity of human bladder. P2X receptors mediate excitation of sensory neurons and evoke muscle contraction in response to ATP release. Anatomical and functional defects in the P2X receptor signaling are associated with a variety of urologic diseases. CONCLUSION: Current research underscores the importance of P2X receptors in urologic physiology. Potential applications exist in relation to the diagnosis and treatment of urinary dysfunction. However, the detailed mechanism of P2X receptor function in bladder physiology and in urinary tract disease remains unknown and warrants further investigation.

Use of tissue expansion for scrotal sac reconstruction after scrotal skin loss.

We describe a two-stage technique for scrotal sac reconstruction using tissue expansion, best described as a tissue expanded V-Y scrotoplasty. This technique has been used after extensive scrotal skin loss, providing excellent functional and cosmetic outcomes.

Complications after cystectomy and urinary diversion in patients previously treated for localized prostate cancer.

OBJECTIVES: To assess the morbidity associated with radical cystectomy in patients who had previously undergone definitive treatment of prostate cancer. METHODS: A retrospective review was undertaken, identifying 35 patients undergoing radical cystectomy with a previous history of radical prostatectomy and/or radiotherapy for prostate cancer. The clinical and surgical information was analyzed to assess patient outcomes. Specific attention was given to the rate, severity, and time course of the postoperative complications. In addition, outcomes after orthotopic and continent cutaneous diversion in this patient cohort were examined. RESULTS: An overall complication rate of 76% was seen in this patient cohort, with 47% of patients experiencing a complication that presented later than postoperative day 30. Radiotherapy was associated with a slightly greater complication rate compared with radical prostatectomy monotherapy (77% versus 71%). Continent urinary diversion (n = 14) was associated with increased morbidity compared with ileal conduit diversion (n = 21). However, a greater percentage of the complications occurring in patients undergoing ileal conduit diversion were major (80% versus 67%). CONCLUSIONS: Our experience has suggested that radical cystectomy in patients previously treated for prostate cancer with radiotherapy and/or radical prostatectomy may be associated with a greater level of morbidity than previously reported. This finding may be, in part, because a significant portion of complications present in a delayed fashion and, as such, have not been seen in previous reports with limited follow-up. For this reason, careful consideration of these risks is necessary when counseling this patient cohort regarding the decision to undergo radical cystectomy.

Defining maximal renal tolerance to warm ischemia in porcine laparoscopic and open surgery model.

OBJECTIVES: To establish the upper limit for warm ischemia time (WIT) beyond which irreversible renal failure will occur in a single-kidney porcine model. The maximal renal tolerance during WIT is currently under revision. Traditionally, 30 minutes was defined as the safe limit for renal WIT. However, accumulating data have suggested that a WIT of up to 90 minutes may not result in permanent damage. METHODS: Twenty female pigs weighing 60 to 80 lb at arrival underwent initial right laparoscopic nephrectomy to create a single-kidney model. Twelve days later, the animals were randomized into four groups of 5 animals each: 120 minutes of open WIT, 120 minutes of laparoscopic WIT, 5 open controls, and 5 laparoscopic controls. Renal function was assessed with serial glomerular filtration rate and serum creatinine measurements, which were assessed preoperatively and on postoperative days (PODs) 1, 3, 8, and 15. RESULTS: No significant difference existed between the laparoscopic and open groups. The glomerular filtration rate reached the lowest value and the serum creatinine levels peaked on POD 3 and were significantly different from baseline at PODs 1, 3, 8, and 15. Renal function did not return to baseline by POD 15, and 66% of the animals showed significant renal insufficiency (more than 25% decline in glomerular filtration rate) in the study group. CONCLUSIONS: After 120 minutes of WIT, no difference in renal function recovery was observed between the laparoscopic and open techniques. A WIT of 120 minutes produced significant renal failure and mortality. Thus, 120 minutes of WIT in the single kidney porcine model exceeds the kidney's tolerance to ischemia.