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David E Rapp

Publications and source records attributed to David E Rapp.

At least 19 recordsLinked to original sources
PubMed2006

Botulinum toxin type a inhibits calcitonin gene-related peptide release from isolated rat bladder.

PURPOSE: Increasing evidence suggests that sensory nerve dysfunction may underlie several urological disorders, including interstitial cystitis and sensory urgency. We determined the effect of botulinum toxin type A (Allergan, Irvine, California) on baseline and chemically evoked release of the sensory neuropeptide, calcitonin gene-related peptide in an isolated bladder preparation. MATERIALS AND METHODS: Whole rat bladders were incubated in a series of tissue baths containing physiological salt solution. Following bladder equilibration in PSS sequential incubation was performed and this sample was used to measure baseline CGRP release. To evoke CGRP release tissue was subsequently incubated in PSS containing capsaicin (30 nM) and adenosine triphosphate (10 microM). To measure the effect of BTX-A on baseline and evoked CGRP release bladders were incubated for 6 hours in an organ bath containing BTX-A (50 microM) or vehicle prior to bladder equilibration. CGRP release was determined by radioimmunoassay. RESULTS: Mean baseline release of CGRP +/- SEM was 346 +/- 44 pg/gm. Adenosine triphosphate/capsaicin application increased CGRP release by 75% over baseline (606 +/- 98 pg/gm, p < 0.005). BTX-A application resulted in a 19% decrease in baseline release of CGRP, although this difference did not achieve statistical significance. BTX-A application significantly decreased evoked CGRP by 62% vs control (606 +/- 98 vs 229 +/- 21 pg/gm, p < 0.005). CONCLUSIONS: BTX-A application inhibits the evoked release of CGRP from afferent nerve terminals in isolated rat bladder. This finding suggests a potential clinical benefit of BTX-A for the treatment of interstitial cystitis or sensory urgency.

Animals↗
PubMed2006

Case report: robot-assisted laparoscopic pyeloureterostomy in a transplanted kidney with ureteral stricture.

Ureteral obstruction secondary to ischemia is the most common urologic complication of kidney transplantation. Although endoscopic management has shown satisfactory short-term success rates, surgical repair is considered the definitive therapy. To our knowledge, this procedure has been performed only through open surgery. We present a minimally invasive approach for reconstruction of a ureteral stricture in a renal transplant patient using the Da Vinci robotic system.

Adult↗
PubMed2005

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.

Animals↗
PubMed2005

Primary malignant melanoma of the urethra.

Primary malignant melanoma of the urethra is an aggressive neoplasm associated with a poor prognosis. The outcome is dependent on early diagnosis and surgical intervention. However, the diagnosis is often delayed as a result of difficulties related to differentiating this lesion from other disorders. Such difficulties result from the variety of clinical and pathologic presentations that are common to melanoma. We report a case of primary malignant melanoma of the urethra with subsequent retrograde seeding of the bladder initially diagnosed and managed as invasive urothelial carcinoma.

Aged↗
PubMed2005

Salvage of end-stage erectile dysfunction using vascularized fibula as autologous implant.

INTRODUCTION: Patients in whom medical and surgical options for the treatment of erectile dysfunction have failed pose a unique challenge to reconstructive genitourinary surgeons. We report a novel reconstructive option for the treatment of end-stage erectile dysfunction using a microsurgically transferred vascularized fibula as an autologous implant in a patient in whom multiple inflatable prostheses had failed. TECHNICAL CONSIDERATIONS: A reconstructive team, consisting of urologic and plastic reconstructive surgeons, transferred a vascularized fibula into the corporeal body in 1 patient to restore sexual function. Using this technique, successful intercourse was achieved by 6 months of follow-up. We describe the surgical technique of autologous implant of a vascularized fibula in the salvage treatment of end-stage erectile dysfunction. CONCLUSIONS: Patients with multiple failed inflatable penile implants can present a formidable challenge to reconstructive surgeons with regard to restoring adequate sexual function. The standard approach to the patient after repeated episodes of unsuccessful salvage of penile prosthesis due to infection and/or extrusion is to remove the prosthesis, leaving the patient impotent. Vascularized autologous tissue transfer provides an option to salvage end-stage erectile dysfunction.

Erectile Dysfunction↗
PubMed2005

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.

Aged↗
PubMed2005

Simplifying laparoscopic partial nephrectomy: technical considerations for reproducible outcomes.

OBJECTIVES: To present our technique, modifications, and experience of laparoscopic partial nephrectomy (LPN). Nephron-sparing surgery is an increasingly accepted treatment for selected T1a kidney tumors. Because of the more complex surgical technique involved, LPN is evolving more slowly than laparoscopic radical nephrectomy. METHODS: The data of 41 consecutive patients with T1a tumors who had undergone LPN from October 2002 to March 2004 were retrospectively reviewed. Four main considerations in our surgical technique were consistently used: (a) LPN was performed in the transperitoneal approach, (b) a suture traction system was placed on the kidney when tumor visualization was challenging, (c) sutures and bolsters were preloaded on the abdominal wall, and (d) hemostasis and closure of the renal defect was performed using Lapra-Ty clips, eliminating knot-tying. RESULTS: The mean patient age was 63.1 years. The mean warm ischemia time was 29.7 minutes, and the mean surgical time was 226.5 minutes. In 26 of 41 patients, the collecting system was entered and repaired. The median estimated blood loss was 150 mL, with a mean tumor size of 2.2 cm. Three cases were converted to open surgery. Five complications (13.2%) occurred. The median hospital stay was 2 days. Of the 41 specimens, 11 were benign. All surgical margins were negative. The mean follow-up was 7.5 months. CONCLUSIONS: Although technically challenging, LPN is emerging as an alternative to open partial nephrectomy. With several easily applied technical considerations, we have simplified LPN, making the procedure more efficient. We believe that the technical considerations we describe can increase the feasibility and ease of LPN for Stage T1a exophytic renal tumors.

Adult↗
PubMed2005

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.

Animals↗
PubMed2005

Intra-operative prostate examination: predictive value and effect on margin status.

OBJECTIVE: To evaluate the ability of intra-operative prostate examination (IOPE) to predict extraprostatic extension (EPE) and its effect on margin status in the region of the neurovascular bundle (NVB) when combined with wide excision. PATIENTS AND METHODS: We retrospectively reviewed 403 patients with clinical stage T1c prostate adenocarcinoma undergoing radical retropubic prostatectomy (RRP). All patients had IOPE during RRP, and those with palpable abnormalities in the region of the NVB underwent wide excision. Pathological outcomes were analysed. RESULTS: Of 403 patients, 49 (12%) had a palpable abnormality in the region of the NVB. After wide excision, 18 (37%) of these 49 patients were found to have EPE at the site of the palpable abnormality; with wide excision of the NVB, only one of these 18 patients (6%) had a corresponding positive surgical margin (PSM). In 354 patients with a normal IOPE and who underwent bilateral NVB preservation, 30 were found to have EPE in the region of the NVB. The PSM rate in this subset was 23% (seven of 30). The positive predictive value of IOPE for detecting EPE was 37%. CONCLUSION: IOPE detects abnormalities in 12% of patients with preoperative stage T1c prostate cancer. Although the predictive value of this test is limited, IOPE may decrease PSMs in a subset of patients with EPE in the region of the NVB. The present study reaffirms the value of IOPE for assessing the risk of extraprostatic disease, and for guiding surgical management.

Adenocarcinoma↗
PubMed2005

Necrotic pancreatic graft causing acute urinary retention.

Urologic complications are frequently encountered after pancreas transplantation with a graft duodenocystostomy. Urinary infections, hematuria, and irritative voiding symptoms are some of the most frequent complications with a bladder-drained pancreas allograft. While voiding dysfunction is common in these patients due to underlying neuropathy, to our knowledge, we report the first case of obstructive uropathy in a female due to retained necrotic graft material.

Adult↗
PubMed2005

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.

Clinical Clerkship↗
PubMed2004

Use of botulinum-A toxin for the treatment of refractory overactive bladder symptoms: an initial experience.

OBJECTIVES: To define the role of botulinum toxin type A (botulinum-A) intradetrusor injections in the treatment of patients with symptoms of bladder overactivity in whom previous anticholinergic therapy has failed. METHODS: Thirty-five patients (29 women and 6 men) with frequency, urgency, and/or urge incontinence received 300 U of botulinum-A toxin injected transurethrally at 30 sites within the bladder. Patients were evaluated at 3 weeks and 6 months after treatment by completion of the short forms of the Incontinence Impact Questionnaire (IIQ-7) and the Urogenital Distress Inventory (UDI-6), as well as questions assessing global response to the treatment. RESULTS: After 3 weeks, the mean IIQ-7 score decreased from 19.4 to 13.9 (P = 0.0006) and the mean UDI-6 score decreased from 16.8 to 12.8 (P = 0.0003). Overall, 21 (60%) of 35 patients reported slight to complete improvement of voiding symptoms after 3 weeks. Among the initial responders followed up for 6 months, the mean IIQ-7 score improved from 20.6 to 15.1 (P = 0.008) and the mean UDI-6 score improved from 16.9 to 13.5 (P = 0.008). Mild hematuria, pelvic pain, and dysuria were seen in 7 patients, lasting for 3 days or less after the procedure. CONCLUSIONS: Botulinum-A toxin injections may provide improvement in symptoms associated with bladder overactivity in a subset of patients. Improvement may be seen for at least 6 months after treatment. The procedure was well tolerated with minimal side effects. Additional study to define the role of injections in a broad group of patients with irritative voiding symptoms is warranted.

Adult↗
PubMed2004

Malignant B-cell lymphoma in renal cyst wall.

Renal cysts are frequently found in adults older than 50 years of age. Bosniak type III and IV cysts are commonly associated with malignancy, but most Bosniak I and II lesions are benign, and the optimal management has not been clearly defined. Although computed tomography and ultrasound examinations have improved diagnostic accuracy, some masses will remain indeterminate and require more invasive evaluation. We report a patient with a Bosniak type II renal cyst associated with malignant B-cell lymphoma in the cyst wall diagnosed after laparoscopic renal exploration.

Humans↗
PubMed2004

En bloc stapling of renal hilum during laparoscopic nephrectomy and nephroureterectomy.

OBJECTIVES: To evaluate the safety and advisability of en bloc mass stapling of the renal pedicle during difficult laparoscopic nephrectomy to avoid conversion to an open procedure. METHODS: A retrospective chart review was performed of 433 consecutive patients undergoing laparoscopic simple or radical nephrectomy or laparoscopic nephroureterectomy between August 1998 and July 2003 by two surgeons. In all cases of en bloc hilar ligation, a stapler was deployed across the renal hilum without individual dissection of the renal artery and vein. RESULTS: The overall incidence of en bloc ligation was 6.0% (26 of 433 patients). The reasons for en bloc ligation were a difficult hilar dissection and/or the appearance of the renal hilum in 21 cases and urgent ligation secondary to bleeding in 5 cases. No correlation was found between surgeon experience and the frequency of en bloc ligation. No immediate or short-term complications related to this method of hilar division were observed with a mean follow-up of 26 months. CONCLUSIONS: In this study, no cases of arteriovenous fistula development occurred after en bloc stapling of the renal pedicle. Long-term follow-up is needed, because arteriovenous fistula development may be a late complication of nephrectomy. Although we do not advocate the generalized use of en bloc division of the renal pedicle, early data suggest that en bloc stapling can be performed to avoid conversion to an open procedure with no related short-term complications.

Arteriovenous Fistula↗
PubMed2004

Use of biopsy sheath to improve standardization of renal mass biopsy in tissue-ablative procedures.

PURPOSE: We used a biopsy sheath to standardize and improve biopsy specimens obtained during laparoscopic cryoablation. MATERIALS AND METHOD: Tru-Cut biopsy was performed using a resized sheath in three patients undergoing laparoscopic cryoablation of renal masses. RESULTS: All three biopsy specimens were sufficient for pathologic evaluation and representative of the tissue mass. CONCLUSIONS: The application of a biopsy sheath to standardize the depth of needle penetration during Tru-Cut biopsy provides better results and minimizes false-negative studies.

Biopsy, Needle↗
PubMed2004

Percutaneous placement of permanent metal stents for treatment of ureteroenteric anastomotic strictures.

PURPOSE: To evaluate the efficacy of permanent metal stent placement in the treatment of ureteroenteric anastomotic strictures following failed balloon dilation or laser endoureterotomy. PATIENTS AND METHODS: Metal stents were placed in six ureteroenteric anastomotic strictures in four patients presenting with recurrent obstruction after balloon dilation or laser endoureteromy. Patients were evaluated at 1 week postoperatively with antegrade ureterography and at 3 to 6 months with renal ultrasound or CT scans. Serum creatinine assays and physical examination were performed at serial postoperative clinic visits. RESULTS: At 1-week follow-up, antegrade studies demonstrated a patent anastomosis in all six strictures. With a mean follow-up of 10 months (range 7-12 months), no stricture recurrence has been seen. All patients have been clinically stable, without episodes of pyelonephritis, flank pain, or need for indwelling stents or nephrostomy tube placement. Serum creatinine concentrations have been stable in all patients. CONCLUSIONS: Metal stents offer a useful treatment option in patients who develop ureteroenteric anastomotic strictures after urinary diversion. Further, such stents may be used in patients failing balloon dilation or laser endoureterotomy. Further study to assess the long-term durability of metal stent placement is needed.

Anastomosis, Surgical↗
PubMed2004

Management of caliceal diverticula.

Although most caliceal diverticula are asymptomatic, they can be associated with pain, and concomitant calculi are common. When treatment is indicated, a variety of surgical options are available, although the management is often a challenge even to the most experienced surgeon. We review the indications, surgical options, and outcomes for the treatment of caliceal diverticula.

Diverticulum↗