Biomedical subjects
Publications and source records attributed to David S Finley.
In this pilot trial in piglets, the authors demonstrated the feasibility of applying robot technology to vascular microsurgery. This preliminary work suggests certain advantages of the robot, which should encourage more rigorous study for its full exploitation.
BACKGROUND AND PURPOSE: An objective evaluation of innate ability and its ability to predict potential success as a surgical trainee is an appealing concept for the selection process of residency applications. The objective of this study was to evaluate whether basic elements of performance (BEP) could discriminate among resident applicants and urologists with various extents of surgical experience. SUBJECTS AND METHODS: One hundred forty-five participants were divided into four study groups: group A, 57 urology residency applicants to the 2002 and 2003 interview process; group B, 8 post-internship urology residents; group C, 19 urologists tested with BEP within 10 years of graduation from their residency training program; and group D, 61 urologists who had graduated from their residency training program more than 10 years prior to testing. The BEP measures consisted of 13 basic performance resources (BPR) including visual-information processing speed, visual-spatial immediate-recall capacity, and neuromotor channel capacity. RESULTS: The four study groups differed significantly in their mean age: group A=27.6 years, group B=29.1 years, group C=37.1 years, and group D=48.9 years (P<0.0005). There was essentially no significant difference between the groups with regard to immediate-recall memory, reaction time simple, or reaction time complicated. The younger participants (groups A and B) were faster than the older surgeons (groups C and D) (P<0.02). However, the older surgeons (groups C and D) were significantly more accurate than the younger groups (A and B) (P<0.0005). The only sex differences noted were in hand-grip strength and shoulder-strength scores, which were all higher in the men. CONCLUSIONS: There generally appears to be a lack of direct correlation between innate abilities and surgical experience. Urology resident applicants with no surgical experience and urology residents with limited surgical experience are faster but less accurate in innate skills testing than experienced practicing urologists.
PURPOSE: To analyze seven cases of hepatic artery pseudoaneurysm (HAP) encountered at our hospital and review the relevant literature. METHODS: We searched the computerized medical record database from January 1, 1996, to September 1, 2003, to identify all cases of HAP, which we then reviewed in detail, examining etiology, findings, laboratory data, therapeutic intervention, complications, and outcome. We then compared these findings with those reported in the literature. RESULTS: There were five cases of HAP among 18,015 trauma and surgical admissions to the University of California Irvine Medical Center, representing an incidence of 0.03%. There were an additional two cases of HAP among 200 orthotopic liver transplants (OLT). The five HAPs not associated with OLT were preceded by blunt abdominal trauma, liver biopsy, pancreatic pseudocyst, and polyarteritis nodosa, in one patient each, and there was no apparent cause in one patient. Two patients were treated by ligation, and the patients with post-OLT HAP underwent resection and replacement with saphenous bypass grafts. Successful embolization was performed in the other three patients. CONCLUSION: Hepatic artery pseudoaneurysm is a rare but dangerous complication of both acute surgical and chronic injury to the hepatic artery. However, early diagnosis and intervention can result in an excellent long-term outcome.
BACKGROUND AND PURPOSE: The effect of laser pulse width on calculus retropulsion during ureteroscopic lithotripsy is poorly defined because of the limited availability of variable pulse-width lasers. We used an adjustable pulse-width Ho:YAG laser to test the effect of pulse width on in vitro phantom-stone retropulsion and fragmentation efficiency. METHODS AND MATERIALS: An Odyssey 30 Ho:YAG laser (Convergent Laser Technologies, Oakland, CA) with adjustable pulse width (350 or 700 microsec) was used to treat spherical 10-mm plaster calculi in a model ureter (N = 40) and calix (N = 16) utilizing 200- and 400-microm fibers (10 Hz, 1.0 J). Calculi were placed in a waterfilled clear polymer tube, and laser energy was applied continuously in near contact until the stone had moved 8 cm. The time (seconds) and energy (joules) needed to cause the stone to traverse this distance was recorded. Stones were also placed in a stainless-steel mesh calix model in which retropulsion was limited. Laser energy was applied for 5 minutes at each pulse width. A laser-energy meter (Molectron Detector Inc, Portland OR) was used to quantify fiber transmission efficiency after 1 minute of continuous lithotripsy for each fiber at each pulse width. RESULTS: Retropulsion was greater for stones treated at 350 microsec, indicated by a shorter time to traverse the model ureter. For the 200-microrm fiber at 350 microrsec, the average time was 11.5 seconds v 20.3 seconds at 700 microsec (P < 0.001). The average total energy delivered was 114.9 J at 350 microsec v 199.8 J at 700 microsec (P < 0.001). For the 400-microm fiber at 350 microsec, the average time was 5.8 seconds v 11.9 seconds at 700 microsec (P < 0.001). The average total energy was 57.1 J at 350 microsec v 127.3 J at 700 microsec (P < 0.001). In the caliceal model, at 350 and 700 microsec with the 200- and 400-microm fibers, mass loss was 34.9% and 33.4% (P = 0.8) and 14.6% and 21.6% (P = 0.04), respectively. The reduction in energy transmission at 350 microsec and 700 microsec with the 200- microm fiber after 60 seconds of continuous lasing was 8.82% v 9%, respectively (P = 0.95). For the 400-microm fiber, the transmission loss was 18.4% at 350 microsec v 4.4% at 700 microsec (P = 0.0002). CONCLUSION: When treating ureteral calculi, retropulsion can be reduced by using a longer pulse width without compromising fragmentation efficiency. For caliceal calculi, the longer pulse width in combination with a 400-microm fiber provides more effective stone fragmentation.
PURPOSE: To determine the effect of urine specific gravity (SG) and radiographic contrast medium on the efficiency of extracorporeal shockwave lithotripsy (SWL) fragmentation using a previously published in vitro model. MATERIALS AND METHODS: Artificial kidney stones (BegoStone [BEGO USA, Smithfield, RI]) of a standard size (10 x 10 mm) and weight (mean 1.90 g; range 1.89-1.91 g) were randomly allotted to one of four test media with differing SG: group 1: synthetic urine, SG 1.003; group 2: synthetic urine, SG 1.040; group 3: 50% radiographic contrast (Cysto-Conray II, Mallinckrodt Inc., Hazelwood, MO), 50% synthetic urine, SG 1.069; and group 4: 100% contrast, SG 1.121. The stones were placed in cups made of 2.2-mm screen mesh and exposed to 500 shockwaves at 20 KV from a spark-gap lithotripter (Econolith 2000; Medispec, Germantown, MD). The stone fragmentation rate (i.e., percent fragmentation) was determined by dividing the dry residual stone weight by the prelithotripsy dry weight (X 100). RESULTS: The mean fragmentation rate for the four groups was 31.7%, 37.6%, 31.8%, and 27.2%, respectively. Statistical significance was not achieved (P = 0.1). CONCLUSION: Stone breakage tends to be more effective when urine SG is about 1.040 than at higher or lower values. Hence, the recommendation for an overnight fast prior to SWL is well founded. Introduction of contrast medium may inhibit stone breakage because it increases the specific gravity.
BACKGROUND AND PURPOSE: As the indications for topical hemostatic agents increase in urology, the question arises: what happens to these agents when they enter the urinary collecting system? To answer this question, we performed a series of in-vitro experiments mixing three hemostatic agents with normal and sanguineous urine. MATERIALS AND METHODS: Four commercially available topical hemostatic products: oxidized regenerated cellulose (Surgicel; Ethicon, Somerville, NJ), fibrin sealant (Tisseel VH Kit; Baxter Health Care Corporation, Irvine, CA), gelatin matrix hemostatic sealant (FloSeal; Baxter Health Care), and polyethylene glycol (CoSeal; Cohesion Technologies, Palo Alto, CA) were studied. Human urine (10 mL) was added to samples of each substance; this was done in triplicate. The 12 sample tubes were then capped and placed on a tube shaker at slow speed and 37 degrees C. Observations regarding consistency of the material were made at 6, 12, 24, 48, 72, 96, and 120 hours (5 days). Gelatin matrix hemostatic sealant was further tested in urine with various amounts of blood or blood clot; observations were again recorded out to 5 days. RESULTS: Surgicel maintained its solid form when it initially came in contact with urine, but over a period of 5 days, it transformed into a mucoid substance with visible free-floating fibers. It did not dissolve completely in urine within 5 days. Gelatin matrix was immediately transformed by urine into a fine colloidal suspension that did not change over the 5 days of the study. Fibrin glue, after mixing of the two components (fibrinogen and thrombin) directly in the urine, and polyethylene glycol immediately formed a solid clot at the bottom of the test tube on contact with the urine. When the mixture of fibrin sealant was allowed to form for 15 minutes and then added to urine, it again maintained a solid form. After 72 hours, the fibrin glue became a semisolid gelatinous plug. On analysis at 5 days, the fibrin sealant clot had transformed into a cohesive mucoid gel, and the polyethylene glycol clot had not changed. The gelatin matrix hemostatic sealant, when in contact with blood or blood clot, appeared to either become part of a clot or to remain in a colloidal suspension. At 5 days, all clots had dissolved to fine particulate suspensions, and the gelatin matrix appeared as a fine suspension. CONCLUSION: Fibrin glue and oxidized regenerated cellulose maintain a solid form when initially placed in direct contact with urine and then assume a semisolid gelatinous state, which is still present at 5 days. Polyethylene glycol forms a solid clot initially and does not change after 5 days. Only hemostatic gelatin matrix remained as a fine particulate suspension in both normal and sanguineous urine. The implications of these findings with regard to sealing the renal parenchyma or small violations of the collecting system after percutaneous or laparoscopic surgery await in-vivo testing.
PURPOSE: We present our experience with standard laparoscopic wedge resection of small renal tumors using a fibrin glue-oxidized cellulose sandwich for hemostasis. MATERIALS AND METHODS: From May 2002 to December 2003, 15 patients underwent laparoscopic wedge resection for a total of 15 nonhilar renal masses. Renal hilar clamping was performed in 1 patient and no sutures were placed. We used ultrasonic shears and an argon beam coagulator to resect and then coagulate the tumor bed. Tisseel (Baxter Corp., Deerfield, Illinois) was applied to the resection bed, followed by a layer of oxidized, regenerated cellulose (Surgicel, Ethicon, Somerville, New Jersey) and a final layer of Tisseel. RESULTS: Mean preoperative tumor size was 2.2 x 2.2 x 2.1 cm. Lesions were subdivided based on the percent of the lesion that extended beyond the renal parenchymal border on computerized tomography as exophytic-greater than 60% in 6 cases, endophytic-less than 40% in 4 and mesophytic-40% to 60% in 5. Mean operative time was 3.8 hours (range 3 to 5). Mean blood loss was 108 ml (range 20 to 300). No patient required blood transfusion. There was no significant difference in blood loss or change in creatinine among the endophytic, exophytic and mesophytic groups (150, 121 and 93 ml, and 0.03, 0.07 and 0.04 mg/dl, respectively). Margin status was negative in all cases (mean thickness 3.2 mm). Average hospital stay and time to the resumption of oral intake were 2.7 and 1.4 days, respectively. CONCLUSIONS: Small exophytic or mesophytic renal lesions can be safely excised laparoscopically without vessel clamping. Excellent hemostasis was achieved in each case with the newer hemostatic agents.
Our experience with 22 renal allograft ruptures (AR) in 4418 transplant recipients over a 20-yr period was reviewed. Fourteen of the 22 ruptured allografts were repaired and eight underwent nephrectomy. All of the repaired AR functioned for 1 yr and 64% functioned at 5 yr. Human leukocyte antigens (HLA) matched and living donor cohorts were predictive factors of salvage. In this large group, renal AR was frequently rescued by primary repair with excellent long-term outcome.
Sildenafil may increase the risk of variceal bleeding in portal hyptertension by increasing splanchnic blood flow. We report herein the second case of variceal rupture after sildenafil use.
A 48 year-old woman with pyelonephritis was found to have bilateral ureteropelvic junction (UPJ) obstruction and a nonfunctioning right kidney. She initially underwent a laparoscopic left nondismembered pyeloplasty using absorbable polydioxanone Lapra-Ty suture clips (Ethicon Endosurgery, Cincinnati, OH) to secure the anastomosis. An antegrade endopyelotomy was later necessitated. Both procedures were complicated by postoperative bacteruria and funguria. She then underwent a laparoscopic dismembered pyeloplasty, again utilizing Lapra-Ty suture clips to secure the anastomosis. Postoperatively, her course was complicated by anastomotic extravasation, bacteriuria, and funguria. Subsequently, an antegrade nephrostogram revealed a 2.5-cm diverticulum just distal to the UPJ, which contained numerous 2- to 4-mm filling defects. Nephroscopic exploration of the pseudodiverticulum revealed numerous Lapra-Ty clips, which were basket extracted. The pseudodiverticulum was fulgurated with a holmium laser. She eventually had restricturing with recurrence of the pseudodiverticulum and was treated successfully by open ureterocalicostomy.