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Biomedical subjects

Chris M Gonzalez

Publications and source records attributed to Chris M Gonzalez.

18 recordsLinked to original sources
PubMed2006

Novel technique for management of distal ureter and en block resection of bladder cuff during hand-assisted laparoscopic nephroureterectomy.

OBJECTIVES: To report our experience with a novel flexible cystoscopic approach to excise the en block bladder cuff and juxtavesical ureter during hand-assisted laparoscopic nephroureterectomy. The optimal technique for excising the distal ureter and bladder cuff during nephroureterectomy continues to evolve. METHODS: Hand-assisted laparoscopic nephroureterectomy was performed in 6 patients. A hand-assist device and two 5 to 12-mm ports were placed in the mid and upper abdomen. Two 10-mm clips were placed on the proximal ureter to occlude it, and the kidney was resected in the usual fashion. An additional 5 to 12-mm port was placed in the midline between the umbilicus and symphysis pubis. The ureter was dissected down into the pelvis to the level of the bladder. Without repositioning the patient, a flexible cystoscope was inserted into the bladder and a 2-cm bladder cuff excised using a 5F electrode on cutting current, with coagulating current used as needed. The specimen was removed intact through the hand port. RESULTS: The mean time to resect the distal bladder cuff was 30 minutes (range 22 to 35). The mean estimated blood loss was 254 mL. The mean operating room time was 264 minutes, mean hospital stay 6.3 days, and mean time to a general diet 2.6 days. All patients underwent cystography at 7 to 10 days postoperatively, with no extravasation or diverticula. Cystoscopic and computed tomography follow-up demonstrated no evidence of recurrence. CONCLUSIONS: This technique allows for complete resection of the kidney, distal ureter, and a cuff of bladder, avoiding repositioning.

Carcinoma, Transitional Cell↗
PubMed2006

Rectourethral fistula associated with two short segment urethral strictures in the anterior and posterior urethra: single-stage reconstruction using buccal mucosa and a radial forearm fasciocutaneous free flap.

INTRODUCTION: We report a novel surgical technique used to repair a rectourethral fistula associated with two short-segment urethral strictures located in the anterior and posterior segments of the urethra in a patient with prior unsuccessful repairs. TECHNICAL CONSIDERATIONS: The anterior urethral stricture was reconstructed with a ventral onlay of buccal mucosa in the exaggerated lithotomy position. In a modified prone position, the rectourethral fistula was repaired using the transrectal transsphincteric (York-Mason) technique and the posterior urethral stricture with a radial forearm fasciocutaneous free flap which was anastomosed to the inferior gluteal artery and vein. The coexistence of a rectourethral fistula and distal urethral stricture requires simultaneous repair, because the urethral pressure from the distal obstruction may compromise fistula closure. Reconstructive efforts should be tailored to minimize disruption of the urethral blood supply in patients with previous pelvic trauma. Rectal and urethral repairs should be separated by well-vascularized tissue to prevent fistula recurrence. CONCLUSIONS: The radial fasciocutaneous flap may offer the reconstructive surgeon another surgical option for complex urethral stricture and rectourethral fistula reconstruction when the local blood supply is in question. Longer follow-up and more cases are needed to further evaluate the continued use of this technique.

Adult↗
PubMed2006

Pathological characteristics of prostate cancer detected through prostate specific antigen based screening.

PURPOSE: Since the introduction of PSA testing for CaP, there has been an increase in CaP detection. However, it is uncertain to what extent clinically insignificant tumors are being diagnosed and treated. In a large, community based population we determined the pathological characteristics of screening detected cancers. MATERIALS AND METHODS: From 1989 to 2001, 35,661 men were enrolled in a longitudinal prostate cancer screening study. Data were available on 3,492 of the 3,568 men (98%) diagnosed with CaP during this study period. Radical prostatectomy was performed in 2,254 men (63%). Clinical stage, Gleason score and pathological analysis were recorded and analyzed in the context of preoperative PSA, digital rectal examination findings, PSA velocity and the year of cancer detection. RESULTS: CaP was detected in 10% of men. Virtually all cases were clinically localized (99.8%) and approximately 70% treated with radical prostatectomy were pathologically organ confined disease. Fewer than 10% of tumors would be considered clinically insignificant based on 2 previously published pathological criteria. CONCLUSIONS: Compared to the high prevalence of CaP found in autopsy studies there is a lower detection rate using current screening protocols. Although the outcomes are unknown if these tumors had been left untreated, the majority met pathological criteria for significant cancer.

Adult↗
PubMed2006

A prospective study of laparoscopic radical nephrectomy for T1 tumors--is transperitoneal, retroperitoneal or hand assisted the best approach?

PURPOSE: We designed a prospective, randomized clinical trial to compare 3 common approaches to laparoscopic radical nephrectomy, namely transperitoneal, retroperitoneal and hand assisted. MATERIALS AND METHODS: A total of 33 patients with a solid renal mass of 7 cm or less were prospectively enrolled in alternating fashion to a hand assisted procedure, a transperitoneal procedure with morcellation and a retroperitoneal procedure with intact specimen extraction. A single surgeon performed all operations. Preoperative, intraoperative and postoperative criteria were compared among the 3 techniques. RESULTS: A total of 11 patients underwent each type of procedure. There was no significant difference in age, American Society of Anesthesiologists class, body mass index or tumor size among the groups. Mean operative time was significantly lower using the hand assisted approach, whereas estimated blood loss was similar in all 3 groups. Incision size, hospital stay and time to normal daily activity were less using the transperitoneal approach. While not significant, there was a trend toward less narcotic use in the transperitoneal group. Hernia formation was seen with increased frequency in the hand assisted group. CONCLUSIONS: In our series the hand assisted approach had significantly shorter operative time than the transperitoneal or retroperitoneal approach but it had the greatest risk of hernia formation. The transperitoneal approach was associated with a significantly shorter hospital stay and the earliest resumption of normal activity.

Adult↗
PubMed2006

Significant clinical practice cost savings through downsizing office supply inventory and just in time ordering.

PURPOSE: Cost containment in the office is becoming more important secondary to increasing overhead costs and lower reimbursement. In an attempt to limit these particular expenditures we analyzed and restructured our methods of ordering, storing and distributing office supply inventory. MATERIALS AND METHODS: In a large academic practice with 11 urologists and approximately 20,000 annual patient visits an attempt was made to decrease overhead costs using the principle of just in time inventory popularized by large manufacturing companies. We initially issued a return of excess and/or unused supplies from our office inventory stock room. Our main supply room was then centralized to contain office supplies for up to 4 weeks. The 12 individual clinic rooms were stocked with appropriate supplies to last 1 week. Limited access to the main supply room was established and a supply manager was established to log all input and output. RESULTS: The initial credit for the return of unused/overstocked supplies was $10,107 in January 2004. Annual office supply charges in calendar year 2004 were $87,444 compared to charges in calendar year 2003 of $175,340. No stock outs occurred during year 2004 and all standing delivery orders were terminated. The total number of patient visits in calendar year 2004 was 20,170 compared to 19,455 in calendar year 2003. CONCLUSIONS: Decreasing overall inventory through accurate demand forecasting, judicious accounting, office supply centralization and just in time ordering is a potential area for significant overhead cost savings in a clinical practice.

Cost Savings↗
PubMed2005

Comparison of donor site intraoral morbidity after mucosal graft harvesting for urethral reconstruction.

OBJECTIVES: To compare postoperative intraoral morbidity after mucosal graft harvesting from the lower lip and inner cheek in men undergoing substitution urethroplasty. METHODS: From 2000 to 2004, 40 patients underwent oral mucosal graft harvesting for urethral reconstruction. Of the 40 patients, 17 underwent harvest from the lower lip (group 1), 19 from the inner cheek (group 2), and 4 from both sites (group 3). We analyzed the postoperative differences in discomfort levels, neurosensory deficits, salivary flow, complications, and overall quality of life according to harvest site. Outcomes were assessed using analog scales and a questionnaire. RESULTS: At longer term follow-up, the proportion of men with persistent postoperative discomfort, neurosensory deficits, and changes in salivary flow was greater in men whose grafts were harvested from the lower lip than in those whose grafts were harvested from the cheek. Contractures were noted in 1 (5.9%) of 17 and 5 (26.3%) of 19 men in groups 1 and 2, respectively. At the last follow-up visit, overall quality of life (measured by an analog scale of 0 [delighted] to 6 [terrible]) was not significantly different in patients with lower lip versus inner cheek harvest (1.35 versus 0.66, respectively, P = 0.079). CONCLUSIONS: Persistent postoperative discomfort, neurosensory deficits, and salivary flow changes were more common in men whose grafts were harvested from the lower lip. However, the overall quality of life in this group was not significantly different compared with men whose grafts were harvested from the inner cheek. From a morbidity standpoint, the inner cheek appears to be the preferable site of graft harvest.

Adolescent↗
PubMed2004

Safety and efficacy of percutaneous nephrolithotomy in patients with neurogenic bladder dysfunction.

OBJECTIVES: To review our experience performing percutaneous nephrolithotomy (PNL) on patients with neurogenic bladder dysfunction with special attention paid to the risks of surgical complications and stone recurrence. Patients with neurogenic bladder dysfunction with or without urinary diversion are at increased risk of urolithiasis, surgical complications, and recurrent stone disease. METHODS: We retrospectively reviewed the 23 patients with neurogenic bladder dysfunction who underwent PNL at our institution. Neurologic lesions included spina bifida, traumatic spinal cord injury, exstrophy/epispadias, neonatal meningitis, stroke, and spine chondrosarcoma. Bladder management included ileal conduit (n = 8), intermittent catheterization (n = 7), indwelling catheter (n = 7), and ureterosigmoidostomy (n = 1). RESULTS: We performed 100 procedures on 47 renal units (17 bilateral, 7 with recurrent stones). Urinary tract infection/colonization was seen in 21 of 23 patients, most of whom had more than one organism. The stone-free rate was 96%. Six patients required three or more procedures, each had a complete staghorn calculus. In an average of 36 months of follow-up, 10 patients (46%) had recurrent stone disease requiring intervention, and 5 patients (23%) underwent repeat PNL. The stone composition analysis revealed mainly infection-related stones. CONCLUSIONS: PNL in patients with neurogenic voiding dysfunction is safe and effective, with outcomes comparable to that of patients without such lesions. The complication rate is small but statistically significant. It is important to obtain adequate urine cultures, because renal pelvis and bladder culture data may differ and affect the outcome. Risk factors for recurrent stone disease include a high spinal cord lesion, indwelling urinary catheter, and ureterosigmoidostomy.

Adolescent↗
PubMed2004

Repair of superior mesenteric artery ligation during left nephrectomy with a native renal vein patch.

Injury to the superior mesenteric artery (SMA) during nephrectomy is a rare but potentially catastrophic complication. SMA injury during nephrectomy most commonly occurs with large tumors or bulky lymphadenopathy, with inadvertent injury or mistaken ligation of the SMA instead of the renal artery. Failure to recognize and repair an SMA injury results in ischemic bowel and death for most patients. We report a case of SMA ligation during left nephrectomy for xanthogranulomatous pyelonephritis, review the intraoperative evaluation of suspected SMA injury, and describe our vascular repair using a vein patch from the native left renal vein.

Blood Vessel Prosthesis↗
PubMed2004

Preoperative PSA level significantly associated with interval to biochemical progression after radical retropubic prostatectomy.

OBJECTIVES: To evaluate the association between the preoperative prostate-specific antigen (PSA) level and the interval to biochemical progression after radical retropubic prostatectomy (RRP) for prostate cancer. METHODS: We studied 5534 men who underwent RRP for prostate cancer during a 15-year period and were enrolled in prospective follow-up studies. Of these men, 857 (15%) subsequently had biochemical evidence of cancer progression (PSA greater than 0.2 ng/mL). All men with biochemical progression after RRP were arbitrarily stratified into five groups according to their preoperative PSA level: less than 2.6 ng/mL, 2.6 to 4 ng/mL, 4.1 to 10 ng/mL, 10.1 to 20 ng/mL, and greater than 20 ng/mL. The time to biochemical progression after RRP was the primary endpoint of the analysis. Other prognostic factors were also evaluated in multivariable analysis. RESULTS: The median time to progression for men with a PSA level greater than 20 ng/mL was significantly shorter (16 months) than for men with a PSA level of 10.1 to 20 ng/mL (27 months) or those with lower PSA levels (P = 0.0005). Men with a PSA level of 4.1 to 10 ng/mL did not have a statistically significantly different median time to progression (31 months) from men with a PSA level of 10.1 to 20 ng/mL (27 months; P = 0.3), 2.6 to 4 ng/mL (32 months; P = 0.8), or less than 2.6 ng/mL (38 months; P = 0.3). Also, no statistically significant difference was found in the median time to progression between men with a PSA level of 2.6 to 4 ng/mL and less than 2.6 ng/mL (P = 0.4). In an analysis of covariance multivariate analysis, the preoperative PSA level was not an independent predictor of the time to biochemical progression (P = 0.12), after accounting for tumor stage and Gleason grade. CONCLUSIONS: The preoperative PSA level was significantly associated with the interval to biochemical cancer progression after RRP; however, this association appeared to be because the preoperative PSA level serves as a surrogate marker for other prognostic factors, such as the tumor volume, tumor stage, and Gleason grade.

Adenocarcinoma↗
PubMed2004

Performance and durability of leading flexible ureteroscopes.

PURPOSE: The role of ureteronephroscopy in the diagnosis and treatment of upper-tract disease has expanded dramatically in recent years with technological advances. In a study involving 14 urologists, we measured the practical performance and durability of the most common commercially available flexible ureteroscopes. PATIENTS AND METHODS: Six commercially available flexible ureteroscopes (Circon-ACMI DUR 8, ACMI DUR 8-Elite, Storz 11274AA, Wolf 7325.172-7.5Fr, Wolf 7330.072-9.0 Fr, Olympus URF-P3) were used consecutively 102 times over a 7-month period. Comparative data, including preoperative and postoperative maximal deflection angles and luminosity, were accumulated, as well as a survey of insertion methods, irrigation methods, instruments used in the working channel, visibility, maneuverability, and overall satisfaction. Maintenance records were analyzed to evaluate the need or reason for repair. RESULTS: Overall satisfaction, visibility, luminosity, and maneuverability were similar for all instruments. The ACMI DUR-8 Elite scored slightly higher than the others, but the difference was not statistically significant. Ureteroscopes were used an average of 10 to 34 times between breakages. The ACMI DUR-8 and DUR-8 Elite instruments had a higher durability score than the others, but with significantly more uses. Channel perforation by a laser fiber was the predominant cause of ureteroscope breakage. CONCLUSIONS: All ureteroscopes performed similarly by objective and subjective criteria. The largest and newest instruments were significantly more durable than the smaller ones, even in the hands of numerous endoscopists. This finding has significant implications for the cost-effectiveness of the various ureteroscopes.

Equipment Design↗
PubMed2003

Prone positioning for bulbar urethral reconstruction.

Exaggerated lithotomy is a surgical position associated with significant morbidity. We describe the use of the prone position for bulbar urethral reconstruction in a selected patient. We propose modified prone positioning as an alternative to exaggerated lithotomy for select patients undergoing reconstruction of the bulbar urethra.

Aged↗
PubMed2002

Pyeloureterostomy with interposition of the appendix.

PURPOSE: We describe the successful repair of a 6 cm. ureteral stricture involving the right ureteropelvic junction and proximal ureter using appendix as a ureteral substitute. MATERIALS AND METHODS: A 37-year-old man involved in a motorcycle accident presented with a retroperitoneal urinoma and a 6 cm. proximal ureteral stricture. At flank exploration we were unable to perform successfully primary pyeloureterostomy through renal descensus with ureteral mobilization. The appendix was selected to bridge the ureteral defect. The right colon and cecum were mobilized to the area of the diseased ureter and the appendix was transected across the base of the cecum. Ureteral scar tissue was resected and the appendix was interposed in an isoperistaltic orientation from renal pelvis to proximal ureter. RESULTS: Convalescence was unremarkable. Retrograde pyelography and flexible ureteroscopy 2 months postoperatively demonstrated a patent anastomosis and viable appendix. The ureteral stent was removed at that time. Excretory urography 3 months postoperatively revealed prompt enhancement of the 2 kidneys and visualization of the 2 ureters. Mercaptoacetyltriglycine-3 renal scan 5 months postoperatively confirmed no scintigraphic evidence of obstruction. The patient was asymptomatic 6 months postoperatively and renal function tests were normal. CONCLUSIONS: The appendix can be considered for proximal ureteral defects extending to the right renal pelvis.

Adult↗
PubMed2002

Irritative voiding symptoms and microscopic hematuria caused by intraperitoneal calcified fat necrosis.

A previously healthy 60-year-old man presented with urinary urgency and microhematuria. The workup revealed no urothelial lesions, but did suggest a calcified intraperitoneal mass causing extrinsic compression of the bladder. Laparoscopic exploration revealed a glistening, spherical mass attached by a stalk to the sigmoid colon. Removal and histologic examination of the mass revealed calcified fat necrosis, most likely due to the spontaneous torsion and calcification of an appendix epiploicae. The patient's symptoms and microhematuria resolved after removal. This case represents an unusual occurrence of irritative voiding symptoms probably due to the extrinsic compression of the bladder by a mass of membranous fat necrosis.

Biopsy↗
PubMed2002

Repair of a diaphragmatic injury during hand assisted laparoscopic nephrectomy using an onlay patch of polypropylene and polyglactin mesh.

PURPOSE: We describe a simple and time efficient technique for repairing a diaphragmatic injury occurring during right hand assisted laparoscopic radical nephrectomy. MATERIALS AND METHODS: A dual layer polypropylene and polyglactin mesh was created extracorporeally by sewing a 2 x 2 piece of polypropylene mesh to a 2 x 2 piece of polyglactin mesh with 4, 4-zero interrupted polyglactin sutures. This dual layer was then positioned manually over the diaphragmatic rent and secured with a laparoscopic stapling device. A 16Fr chest tube was placed at the conclusion of the procedure. RESULTS: Overall operative time was 3.5 hours with an estimated blood loss of 100 cc. Repair of the diaphragmatic injury extended operative time by 25 minutes. Extubation was done at the conclusion of the case and the chest tube was removed within 36 hours of the procedure. The patient was discharged home on postoperative day 3. At 14 months of followup the patient remained disease-free on radiography and without pulmonary or gastrointestinal sequelae. CONCLUSIONS: We describe a simple and time efficient technique for repairing diaphragmatic injury occurring during right hand assisted laparoscopy. This technique takes advantage of the manual and tactile sensation provided by the hand assistance device, provides a tension-free repair and avoids laparoscopic suturing.

Chest Tubes↗