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Biomedical subjects

David E Rapp

Publications and source records attributed to David E Rapp.

At least 19 recordsLinked to original sources
PubMed2007

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.

Animals↗
PubMed2006

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.

Animals↗
PubMed2006

Urethral polyp in asymptomatic male infant with prenatal hydronephrosis.

Congenital posterior urethral polyps are rare, benign lesions of the posterior urethra. We report a 1-day-old newborn boy with a solitary fibroepithelial posterior urethral polyp who presented with a history of prenatal mild hydronephrosis, subsequently associated with bladder wall thickening on ultrasonography.

Cystoscopy↗
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↗
PubMed2006

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.

Humans↗
PubMed2006

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.

Aged↗
PubMed2006

Integrating cultural competency into the undergraduate medical curriculum.

CONTEXT: A significant movement is underway to develop standardised curricula that provide medical students with a fundamental knowledge of cultural sensitivity. METHODS: This paper reviews the recent initiative to integrate cultural competency training into the curricula of American undergraduate medical institutions. RESULTS: Despite these initiatives, few medical institutions have achieved a comprehensive curriculum providing for continued cultural experiences and assessment of related skill sets. The article proposes a framework for the introduction of continued instruction in and assessment of cultural competency within the undergraduate medical education. CONCLUSIONS: The described components of cultural competency education in the undergraduate medical curricula provide a framework to facilitate early and continued exposure to experiences designed to promote cultural sensitivity.

Clinical Competence↗
PubMed2006

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.

Aged↗
PubMed2006

Intravesical botulinum type A toxin injection in patients with overactive bladder: Trigone versus trigone-sparing injection.

OBJECTIVE: Botulinum toxin type A (BTX-A) has been successfully used in the treatment of patients with overactive bladder (OAB) symptoms refractory to anticholinergic therapy, with most studies performing trigone-sparing detrusor injections. Increasing evidence suggest that sensory nerve dysfunction contributes to the pathophysiology of OAB and, for this reason, targeting the afferent innervation of the bladder trigone during injection may provide clinical benefit. MATERIALS AND METHODS: We conducted a pilot study to assess the benefit of trigonal-inclusion during BTX-A injection. A total of 40 patients with OAB refractory to anticholinergic treatment received trigone or trigone-sparing injection of BTX-A. Patients were evaluated using UDI-6 and IIQ-7 questionnaires prior to the BTX-A applications, at 3 weeks and 6 months after treatment. RESULTS: At 3-week follow-up, 15/24 (63%) and 10/16 (63%) patients showed improvement of symptoms in the trigone versus trigone-sparing groups, respectively. Combined 3-week UDI-6 and IIQ-7 scores improved from 37.3 prior to treatment to 27.4 (p < 0.05) and 35.5 to 27.2 (p < 0.05) in the trigone and trigone-sparing groups, respectively. Six-month follow-up demonstrated continued but diminished levels of symptom improvement when compared to pre-treatment and 3-week symptom scores. Improvement in symptom scores between the trigone and trigone-sparing groups was not significant. CONCLUSION: No significant difference in symptom score or treatment response was noted between the trigone and trigone-sparing groups. Further study using pre- and post-operative urodynamic study is needed to evaluate possible benefit to trigonal injection in a select sensory urgency cohort, and to assess for urodynamic improvement following trigonal injection.

Administration, Intravesical↗
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↗