Longterm changes in creatinine clearance after laparoscopic renal surgery.

BACKGROUND: Controversy exists about the impact of ischemia on renal function. We evaluated the creatinine clearance of patients having undergone laparoscopic renal extirpative and ablative surgery. STUDY DESIGN: The records of patients undergoing laparoscopic procedures for renal masses from February 2000 to March 2004 were examined. Creatinine clearance (CrCl) for each patient was determined using the Cockcroft-Gault equation and ideal body weight. We compared CrCl changes of patients undergoing laparoscopic partial nephrectomy (without renal ischemia [LPN-none], with warm ischemia [LPN-warm], and with cold ischemia [LPN-cold]) with patients undergoing laparoscopic radical nephrectomy (LRN) and laparoscopic cryoablation. Patients predisposed to medical renal disease were substratified and evaluated. RESULTS: All patients who underwent LRN or LPN-warm sustained a significant drop in CrCl on the first postoperative day, compared with patients who had LPN without ischemia or cryoablation (p < 0.01). The CrCl decrease correlated directly with warm ischemia time. Six months postoperatively, CrCl changes were no longer significant. Patients with medical renal disease risk factors were more likely to sustain longterm (1 year postoperatively) renal damage if they had renal ischemia, trending toward statistical significance. CONCLUSIONS: Ischemia causes acute renal damage, which is apparently reversible in patients without evidence of medical renal disease. Patients with known medical renal disease have substantial longterm changes in renal function associated with unilateral renal ischemia. Considering the insensitivity of creatinine-based renal function metrics, only eliminating ischemic time will realize the goal of maximal nephron preservation, particularly in patients with preexisting medical renal disease.

Analysis of surgical smoke produced by various energy-based instruments and effect on laparoscopic visibility.

PURPOSE: We analyzed the smoke plume produced by various energy-based laparoscopic instruments and determined its effect on laparoscopic visibility. MATERIALS AND METHODS: The Bipolar Macroforceps, Harmonic Scalpel, Floating Ball, and Monopolar Shears were applied in vitro to porcine psoas muscle. An Aerodynamic Particle Sizer and Electrostatic Classifier provided a size distribution of the plume for particles >500 nm and <500 nm, and a geometric mean particle size was calculated. A Condensation Particle Counter provided the total particle-number concentration. Electron microscopy was used to characterize particle size and shape further. Visibility was calculated using the measured-size distribution data and the Rayleigh and Mie light-scattering theories. RESULTS: The real-time instruments were successful in measuring aerosolized particle size distributions in two size ranges. Electron microscopy revealed smaller, homogeneous, spherical particles and larger, irregular particles consistent with cellular components. The aerosol produced by the Bipolar Macroforceps obscured visibility the least (relative visibility 0.887) among the instruments tested. Particles from the Harmonic Scalpel resulted in a relative visibility of 0.801. Monopolar-based instruments produced plumes responsible for the poorest relative visibility (Floating Ball 0.252; Monopolar Shears 0.026). CONCLUSIONS: Surgical smoke is composed of two distinct particle populations caused by the nucleation of vapors as they cool (the small particles) and the entrainment of tissue secondary to mechanical aspects (the large particles). High concentrations of small particles are most responsible for the deterioration in laparoscopic vision. Bipolar and ultrasonic instruments generate a surgical plume that causes the least deterioration of visibility among the instruments tested.

Laparoscopic cryoablation for small renal masses: three-year follow-up.

OBJECTIVES: To report our experience with laparoscopic renal cryoablation for patients who have completed a minimum of 3 years of follow-up. METHODS: From July 2000 to March 2005, 81 patients underwent laparoscopic renal cryoablation for renal masses. Of these 81 patients, 31 (38%) underwent laparoscopic renal cryoablation for 36 tumors and have completed a minimal follow-up of 3 years (mean 45.7 months). The postoperative follow-up protocol consisted of serial contrast-enhanced computed tomography or magnetic resonance imaging at 1 day, 1, 3, 6, and 12 months, and yearly thereafter. RESULTS: Twenty-seven tumors were partially exophytic, five were totally endophytic, and four were hilar tumors. The mean operative time was 2.9 hours, with a mean estimated blood loss of 97 mL. The mean renal tumor size was 2.1 cm. In early follow-up, the ablation zone was larger than the tumor but subsequently diminished to the original tumor size 6 months postoperatively. Thereafter, the ablation zone size decreased. The biopsy results revealed that 22 tumors (61%) were malignant and 14 (39%) were benign. The renal tumor 3-year cancer-specific survival rate was 100%, and no patient developed metastatic disease. One patient demonstrated return of abnormal enhancement within the cryolesion during follow-up, suggesting tumor recurrence. One patient had a hemorrhage and urinary leak after cryoablation of an endophytic tumor and was treated conservatively. CONCLUSIONS: Renal cryoablation is safe and offers a minimally invasive nephron-sparing alternative. The oncologic adequacy of renal cryoablation requires long-term follow-up data, but the intermediate-term data seem equivalent to that achieved with extirpative therapy.

Correlation of ureteric length with anthropometric variables of surface body habitus.

OBJECTIVE: To evaluate the association of variables of body habitus with direct measurements of ureteric length, as the correct choice of ureteric stent length might help to prevent complications and improve stent tolerance, and to date there are limited data correlating height or other body variables with ureteric length. PATIENTS AND METHODS: We prospectively measured pelvi-ureteric junction to vesico-ureteric junction length in 100 patients by placing a ruled 5 F ureteric catheter. Ureteric length was then correlated with patient height, weight, body mass index, and distance from the shoulder (acromium process) to the wrist (head of the ulna; S-W), the elbow (olecranon process) to the wrist (head of the ulna), xyphoid process to umbilicus, xyphoid process to pubis (X-P), umbilicus to pubis, and anterior iliac spine to anterior iliac spine. Patients with pathology affecting the ureteric length were excluded. The results were analysed statistically using a multiple linear regression model with stepwise selection of variables, and a paired t-test. RESULTS: The mean right and left ureteric lengths were similar (P=0.61); height (P<0.01), weight (P=0.02), X-P (P=0.01), and S-W (P=0.02) distances all correlated with ureteric length. On multivariate regression analysis, weight, height and male gender were associated with mean ureteric length. From these data a formula was constructed to predict ureteric length. CONCLUSIONS: It is a challenge to predict ureteric length from body habitus, but height, X-P distance and S-W distance can be used to predict ureteric length.

Pharmacologic manipulation of the porcine ureter: Acute impact of topical drugs on ureteral diameter and peristaltic activity.

BACKGROUND AND PURPOSE: Intraluminal application of pharmacologic agents for acute ureteral dilation may facilitate difficult ureteroscopy. We characterized the in-vivo effects of intraluminal application of verapamil and theophylline on ureteral peristalsis and diameter in a porcine model. MATERIALS AND METHODS: Twenty-four female domestic pigs (35-40 kg) were incorporated into the study. We deployed a giant magneto resistive (GMR) sensor and electromagnetic (EMG) electrodes laparoscopically onto the ureteral surface for simultaneous measurement of the mechanical and electrical signals of ureteral peristalsis, respectively. The ureteral-luminal diameter was measured at three levels by digital retrograde pyelography and standardized to a 10-mm laparoscope. The results were calculated as change in peristalsis and ureteral diameter from baseline during the first hour after drug injection. We tested two smooth-muscle relaxants, verapamil (2 mg/kg) and theophylline (70 mg/kg), with saline and dimethylsulfoxide (DMSO; solvent) as controls. Six pigs were studied for each of the four groups. Hydration, anesthesia, and intra-abdominal pressure were standardized. The serum concentrations of the drugs were measured to determine systemic absorption. RESULTS: During the first 10 minutes after intraluminal drug injection, theophylline caused a significant decrease in ureteral peristalsis (6.75 waves/10 minutes) compared with the control group (1.00/10 minutes; P = 0.02). This trend persisted for the next hour. However, there were no changes from baseline in ureteral width. Ureteral peristalsis and dilation remained similar after the saline and DMSO injections. Verapamil increased the diameter of the proximal ureter compared with the controls throughout the hour after drug injection. Fifteen minutes after the drug injection, the change in the ureteral diameter with verapamil was 1.38 mm (4.14F), while the control group showed a change of 0.27 mm (P = 0.03). At 1 hour, the width of the proximal ureter in the verapamil group had increased by 1.72 mm (5.16F), while the control group had changed by 0.55 mm (P = 0.03). There were no statistically significant changes in the widths of the mid or distal ureter. No ureteral dilation was observed in the other groups. CONCLUSIONS: In the porcine model, intraluminal application of pharmacologic agents produced independent effects on ureteral dilation and peristalsis. Theophylline inhibited ureteral peristalsis, and verapamil produced acute proximal-ureteral dilation. The ability to alter ureteral diameter or peristaltic activity acutely may facilitate ureteroscopy.

Precise characterization of renal parenchymal response to single and multiple cryoablation probes.

PURPOSE: We characterized the size and shape of the ablated area, and the surrounding indeterminate zone associated with renal cryolesions produced by single and multiple cryoablation probe configurations in a porcine model. MATERIALS AND METHODS: Laparoscopic cryoablation, consisting of 2, 10-minute double freeze cycles followed by a 3-minute active thaw, was performed in 18 pigs. Three groups of 6 pigs each were studied, including a single IceRod, 3 rods arranged in a triangular configuration 2 cm apart from each other and 4 rods arranged in a quadratic configuration 2 cm from each other. Cryoablated kidneys were harvested after 14 days for histopathological evaluation. RESULTS: The mean diameter of the area of complete ablation produced by a 1, 3 and 4 rod configuration 1 cm from the tip of the rod was 2.0, 4.4 and 4.9 cm, respectively. Cryolesions were elliptical with 1 cryoablation probe and in the 3 and 4 rod configurations they conformed to triangular and quadratic cross-sectional shapes, respectively. In the zone, ablation a single small focus of peri-arteriolar renal cell viability was noted less than 1 mm from the edge of the cryolesion in 1 of the 18 cryolesions. Otherwise no viable renal cells were detected. CONCLUSIONS: Multirod configurations can be used with templates to space cryoablation probes 2 cm apart from each other with reliable and complete ablation overlap between the rods. However, around larger blood vessels the ice ball must be extended to a larger margin to ensure complete tissue ablation.

Evaluation of a novel knotless self-anchoring suture material for urinary tract reconstruction.

OBJECTIVES: To evaluate a novel prototype self-anchoring suture (SAS) material that incorporates unidirectional "barbs" designed to grip and approximate tissue without the need for suture ligation for urinary tract reconstructive procedures. METHODS: The in vitro failure strength of various porcine tissue approximations with SAS was compared with the strength of similar approximations with standard ligated suture. For in vivo analysis, 3 pigs underwent laparoscopic pyeloplasty with SAS on one side and 2-0 Vicryl suture on the contralateral side. Nine pigs underwent bladder neck anastomoses (BNA) performed with SAS (n = 3) and standard ligated interrupted suturing (n = 3) or standard ligated running suturing (n = 3). The operative times were compared. One week after surgery, the integrity of each anastomosis was evaluated radiographically and histopathologically. RESULTS: The in vitro analysis revealed no statistically different (P = 0.22) failure forces between the approximations performed with SAS (13.2 +/- 2.6 N) and standard suture (14.1 +/- 3.1 N). The in vitro analysis revealed no difference in operative times for the pyeloplasties (P = 0.72) or BNA (P = 0.31). None of the 1-week postoperative radiographic studies revealed extravasation. The histopathologic analysis revealed more fibrotic reaction associated with the SAS BNA procedures (P <0.01). CONCLUSIONS: Self-anchoring suture secures tissue approximations at loads equivalent to tissue approximations with standard tied suture. Self-anchoring suture obviates the need for knot tying and provides a watertight anastomosis. With laparoscopic knot tying experience, anastomotic time with SAS and standard suture do not differ. Self-anchoring suture might induce more fibrosis. Long-term follow-up evaluation will be required before clinical application.

Durability of flexible ureteroscopes: a randomized, prospective study.

PURPOSE: We performed a randomized, prospective, multi-institutional study evaluating the durability of commercially available flexible ureteroscopes. MATERIALS AND METHODS: A total of 192 patients were randomized to the use of 7 less than 9Fr flexible ureteroscopes, including the Storz 11274AA and Flex-X, the ACMI DUR-8 and DUR-8 Elite, Wolf models 7330.170 and 7325.172, and the Olympus URF-P3. Information about total and lower pole use time, the number and method of ureteroscope insertion, and they type and duration of accessory instrumentation was recorded. Surgeons were asked to rate the visibility and maneuverability of the instrument on a scale of 0-poor to 10-excellent. RESULTS: The indication for ureteroscopy was upper tract calculi in 87% of cases. Of ureteroscope insertions 97% were performed through an access sheath. The average of number of cases before repair ranged from 3.25 for the Wolf 7325 to 14.4 for the ACMI DUR-8 Elite. Average ureteroscope operative time was statistically longer for the DUR-8 Elite (494 minutes) than for the Flex-X (p = 0.047), and the Wolf 7325 and 7330 (p = 0.001 and 0.001, respectively). Duration of use before repair for the URF-P3 (373 minutes) was statistically longer than for the Wolf 7325 and 7330 (p = 0.016 and 0.017, respectively). Minutes of use with an instrument in the working channel were significantly more with the DUR-8 Elite and the URF-P3 than the Wolf 7330 (p = 0.017 and 0.008) and 7325 (p = 0.012 and 0.005, respectively). The ureteroscope that experienced the greatest average duration of lower pole use was the URF-P3, while the shortest was the Wolf 7325 (103 vs 20 minutes, p = 0.005). Average minutes of laser use before breakage was significantly longer for the DUR-8 Elite than for the Wolf 7325 (110 vs 21 minutes, p = 0.021) and 7330 (24 minutes, p = 0.025). CONCLUSIONS: Currently available less than 9Fr flexible ureteroscopes remain fragile instruments. The DUR-8 Elite and Olympus URF-P3 proved to be the most durable devices.

Laparoscopic partial nephrectomy for renal masses: effect of tumor location.

OBJECTIVES: To report our single institutional experience of laparoscopic partial nephrectomy (LPN) for enhancing renal masses and evaluate outcomes and histopathologic findings with respect to the location of the renal mass. METHODS: A retrospective review of LPN for 123 renal masses completed by 7 urologists was performed. Of these lesions, 49 (40%) were exophytic, 19 (15.5%) endophytic, 47 (38%) mesophytic, and 8 (6.5%) were hilar. We defined exophytic as more than 60%, mesophytic as 40% to 60%, and endophytic as less than 40% of the renal mass protruding off the surface of the kidney on radiologic imaging studies. Hilar lesions were those located within 5 mm of the renal hilar structures, regardless of the surface characteristics. RESULTS: The mean tumor size was 2.6 cm (range 1 to 9). Hilar vessel clamping was performed during 55 procedures (44.7%); the mean warm ischemia time was 27 minutes (range 12 to 52). On final histopathologic examination, 3 patients (2.5%) had positive tumor resection margins. Overall, 26 (20.6%) complications occurred. The complication rate was significantly less for patients who underwent LPN for an exophytic (10%) or a mesophytic (12.8%) mass than for those with an endophytic (47%) or a hilar (50%) mass. Histopathologic examination of the renal masses revealed malignant pathologic features in 86 (69%) and benign findings in 37 (31%). In our series, only 55% of exophytic tumors were malignant and, if malignant, were invariably low grade (96%). CONCLUSIONS: The complications of LPN and the malignancy rate of the renal lesions were related to the tumor location within the kidney.

Comparison of mechanical and in vivo performance of new and reprocessed harmonic scalpels.

OBJECTIVES: To compare the mechanical and clinical performance of new and reprocessed harmonic scalpels (HS). METHODS: A total of 89 reprocessed and 90 new HS (laparoscopic coagulating shears with a curved blade and 5-mm-diameter shaft) were subjected to visual inspection, destructive testing, and nondestructive mechanical testing. Subsequently, new HS, randomly selected reprocessed HS, and selected reprocessed HS with known abnormalities were graded on clinical performance by 14 surgeons in a porcine model. RESULTS: Visual inspection of the HS discriminated between the new and reprocessed instruments in 11 of the 12 visual criteria (P < or = 0.02). In vitro mechanical testing revealed greater clamp arm dislodge forces for the new HS (P < 0.01) and greater midshaft temperatures for reprocessed HS (P < 0.01). Overall, 65 (73%) of 89 reprocessed and 7 (7.8%) of 90 new HS had gross abnormalities noted on inspection and mechanical evaluation (P < 0.01). The surgeons' evaluation of the instruments during in vivo testing demonstrated that the new instruments manifested significantly greater hemostatic control compared with randomly selected reprocessed HS (P = 0.01) and were significantly better for tissue sticking (P = 0.01), tissue transection (P = 0.02), tissue dissection (P < 0.01), grasping (P < 0.01), and hemostatic control (P = 0.04) compared with reprocessed HS with obvious defects. CONCLUSIONS: In vitro and in vivo data demonstrated significantly greater performance for new HS compared with reprocessed HS. Mechanical testing of reprocessed HS could not adequately distinguish which HS would result in decreased performance. These findings raise important issues of clinical safety in the contemporary quest for cost-effectiveness.

Assessment of efficacy of transcutaneous electrical nerve stimulation for pain management during office-based flexible cystoscopy.

OBJECTIVES: To evaluate the efficacy of transcutaneous electrical nerve stimulation (TENS) for its effectiveness in eliminating or minimizing discomfort during office-based flexible cystoscopy. METHODS: A total of 148 patients were prospectively randomized into one of three groups: flexible cystoscopy with no analgesics, a placebo TENS, or an activated TENS. The patient data collected included patient parameters, number of previous flexible cystoscopies, visual analog pain scores during and after the procedure, surgeon's difficulty rating of procedure, and International Prostate Symptom Score before and 24 hours after the procedure. RESULTS: No statistically significant difference was found among the three groups regarding patient parameters. The visual analog pain scores were similar before and after the procedure. At 30 seconds, the mean visual analog scale score for the control group, placebo group, and TENS study group was 3.73, 3.65, and 3.52, respectively (control versus placebo, control versus active, and placebo versus active: P = 0.97, 0.29, and 0.53, respectively). At 1 and 5 minutes, the corresponding scores were 3.44, 4.37, and 3.50 (P = 0.88, P = 0.99, and P = 0.99) and 0.86, 1.23, and 0.88 (P = 0.97, P = 0.35, and P = 0.56), respectively. The surgeon's mean difficulty rating for the control procedures was 1.08 and for the placebo group was 2.30 (P = 0.02). CONCLUSIONS: All patients undergoing flexible cystoscopy in the office setting experienced discomfort. The TENS device provided no significant benefit for pain. The trend toward greater pain scores in the control group could be attributed to the greater degree of difficulty.

Evaluation of laparoscopic performance with alteration in angle of vision.

BACKGROUND AND PURPOSE: Optimal placement allows intuitive laparoscope positioning between two working trocars (0 degrees angle). However, this configuration may require the assistant to operate in an awkward position. We evaluated the effect of alteration of laparoscope position on surgeon performance and correlated this with surgical experience. SUBJECTS AND METHODS: Participants were stratified by laparoscopic experience. Group 1 (N = 10) was naïve (no surgical experience), group 2 (N = 7) had moderate laparoscopic experience (1-100 cases), and group 3 (N = 6) was laparoscopically experienced (>100 cases). Participants were timed performing a simple laparoscopic task three times in a trainer with camera angles randomized along the horizontal plane: 0 degrees , 45 degrees , 90 degrees , 135 degrees , and 180 degrees . RESULTS: All participants showed progressive deterioration in performance as the angle deviated from baseline. The mean time required to complete the tasks was significantly higher for group 1 v groups 2 and 3 at 135 degrees (158 v 77 and 73 seconds) and 180 degrees (153 v 89 and 86 seconds). Performance curves for each group revealed more pronounced deterioration of performance with alteration in the angle of vision in group 1 than in groups 2 and 3 (P < 0.01). There was no difference between groups 2 and 3 (P = 0.19). CONCLUSIONS: Even modest alteration in laparoscopic perspective results in deterioration of performance for all levels of surgical experience. Experienced laparoscopists adapt more quickly to complexities presented by alteration in camera angles. Novice surgeons should focus on trocar positioning to maintain intuitive surgical perspective and should refrain from working with alterations in camera angles until significant laparoscopic experience has been gained.

Alteration in irrigant flow and deflection of flexible ureteroscopes with nitinol baskets.

BACKGROUND AND PURPOSE: Introduction of an instrument into the working channel of ureteroscopes adversely affects flow and deflection. We evaluated the alterations in ureteroscope channel flow and deflection caused by available Nitinol(R) baskets. MATERIALS AND METHODS: We compared the effects of 11 Nitinol baskets on irrigation flow and deflection of three flexible ureteroscopes (Olympus P3, ACMI DUR8, and ACMI DUR8 Elite). ANOVA was used to compare the loss of flow and deflection for each basket, with P values adjusted for multiple comparisons by the Tukey method. RESULTS: Ureteroscope flow and deflection were progressively adversely affected by all baskets as their diameter increased. The average baseline irrigant flow (46.6 mL/min) was decreased significantly: by 78.5% (to 9.9 mL/min), with the smaller baskets (Microvasive 1.9F and Cook 2.2F) and by 99.1% (to 0.4 mL/min) with the larger baskets (ACMI 3.0F and Microvasive 3.0F). Similarly, the mean baseline upward deflection (162 degrees) decreased by 2 degrees (1.2%) for the Cook 2.4F N-Compass and by 20 degrees (12.3%) for the ACMI 3.0F. Loss of downward deflection from baseline (170 degrees) ranged from 6 degrees (3.5%) for the Microvasive 1.9F to 17 degrees (10%) for the Microvasive 2.6F grasping forceps. The least deterioration in flow and deflection occurred with the two smallest baskets (Microvasive 1.9F and Cook 2.2F). CONCLUSION: Ureteroscope irrigation flow and deflection deteriorate progressively with larger-caliber Nitinol baskets. The Microvasive 1.9F and Cook 2.2F baskets resulted in the least deterioration of irrigation and deflection metrics. However, basket size is not the only factor responsible for changes in flow and ureteroscope deflection.

Comparison of holding strength of suture anchors for hepatic and renal parenchyma.

BACKGROUND AND PURPOSE: Various laparoscopic devices have been described for suture anchoring during solidorgan parenchymal closure. Application of these devices expedites the closure of parenchymal defects and minimizes ischemia time. We compared different technologies as suture anchors for parenchymal closure. MATERIALS AND METHODS: A tensometer was used to determine the amount of tension necessary to dislodge each of five different clips from Vicryl suture alone or against two different substrates (fresh pig kidney and liver) with and without an intervening pledget. The clips investigated were the Lapra-Ty (Ethicon), Endoclip II (US Surgical), small Horizon Ligating Clips (Weck), Hem-o-lok Medium Polymer Clips (Week), and a novel Suture-clip (Applied Medical). ANOVA and two-sided Fisher's exact test provided statistical analysis. RESULTS: The force required to dislodge the Lapra-Ty clip from bare suture for both 0 and 1 Vicryl (7.0 N) was approximately fourfold the force required to dislodge the Endoclips or the 5-mm or 10-mm Hem-o-lok clips (p<0.01). When clips were applied to suture running through renal or liver parenchyma, the novel Suture-clip required the greatest tension to dislodge (P<0.01), followed by the Horizon and Lapra-Ty clips. There were no statistically significant differences in the tension required to dislodge a given clip from the two parenchymal substrates or in the presence or absence of a pledget. CONCLUSIONS: In our experimental model, the Suture-clip, Lapra-Ty, and Horizon clips required significantly greater tension to dislodge than the Hem-o-lok and Endoclip clips. The addition of a pledget did not improve tension resistance.

Comparison of running and interrupted vesicourethral anastomoses in a porcine model.

PURPOSE: To compare running and interrupted suturing techniques for porcine vesicourethral anastomosis with regard to procedure time, histopathologic effects, and leakage. MATERIALS AND METHODS: Twelve domestic pigs were randomized to a running (N = 6) or an interrupted (N = 6) vesicourethral anastomosis with polyglycolic acid sutures. In each case, the bladder was drained for 7 days. A cystogram was performed immediately after completion of each anastomosis and on postoperative days 7 and 30. Animals were sacrificed on postoperative day 30, and the area of the anastomosis was excised en bloc for histopathologic evaluation. RESULTS: All procedures were completed laparoscopically. The mean operative time for continuous and interrupted suturing were 27.5 and 36.8 minutes, respectively (P = 0.3324). A significant learning curve was noted for both anastomoses, with operative times decreasing with experience in both groups. There was no difference in anastomotic leakage. Histopathology examination revealed more muscle-layer fibrosis in the interrupted- suture group than in the continuous-suture group, with a mean score of 2.17 and 1.67, respectively (P = 0.0325). CONCLUSIONS: Both continuous and interrupted vesicourethral anastomoses are feasible. In this in-vivo porcine comparison, there was no difference with respect to procedure time or anastomotic leakage. However, histopathologic grading demonstrated greater muscle fibrosis in the interrupted-suture group.

Extrarenal vascular anatomy of kidney: assessment of variations and their relevance to partial nephrectomy.

OBJECTIVES: To evaluate the feasibility of selective segmental artery clamping during partial nephrectomy. METHODS: Precise extraparenchymal renal hilar dissection was performed on 73 fixed cadaveric kidneys. The surgical accessibility to clamping of each presegmental and segmental artery from the anterior and posterior approaches was determined on the basis of vessel length, position within the renal hilum, and degree of overlying collecting system or venous structures. RESULTS: The vascular anatomy consisted of zero, one, or two presegmental arteries (extrarenal main renal artery branches that split into two or more segmental arteries) in 49.3%, 31.5%, and 19.2% of the kidneys, respectively. From a posterior approach, the posterior segmental artery was accessible to isolated clamping in 81.8% of the kidneys (segmental accessibility rate) and was accessible to clamping at the presegmental level in 12.7% (presegmental accessibility rate) for a total accessibility rate of 90.9%. The total accessibility rate for the inferior segmental artery was 88.5% from an anterior and 66.7% from a posterior surgical approach. The apical artery total accessibility rate was 72.3% and 40.5% from an anterior and posterior approach, respectively. The corresponding middle and superior segmental artery total accessibility rates were 50.8% and 32.8%. CONCLUSIONS: In this cadaveric model, hilar dissection and clamping of the renal segmental arteries is anatomically feasible in most cases. Posterior and polar tumors will likely be more amenable to segmental vascular control. Selective segmental vascular control may offer the benefits of total hilar control while reducing overall renal ischemic injury.

Prospective evaluation of learning curve for laparoscopic radical prostatectomy: identification of factors improving operative times.

OBJECTIVES: To evaluate the time required for each component of laparoscopic radical prostatectomy (LRP) performed by a single surgeon to identify the factors that expedite the learning curve. LRP is a technically demanding procedure with a lengthy learning curve. METHODS: The LRP procedure was divided into 12 steps, and the time for each step was prospectively recorded during the first 50 consecutive patients undergoing LRP by a single surgeon. The operations were divided into five groups of 10, and the average times for each step were compared and correlated with surgeon observations and changes in surgical technique. RESULTS: Statistically significant progressive improvement was seen in the total time of the LRP procedure (269.4 minutes in period 1 versus 205.4 minutes in period 4, P < 0.05). Regarding the specific steps, improvement occurred in the time needed for dissection of the vas deferens and seminal vesicles (51.8 minutes for period 1 versus 25.3 minutes for period 4, P < 0.01 and 31.2 minutes for period 5, P < 0.03), apical incision (16.7 minutes for period 1 versus 6.3 minutes for period 4, P < 0.03 and 5.7 minutes for period 5, P < 0.02), and division of the rectourethralis (13.5 minutes for period 1 versus 3.4 minutes for period 5, P < 0.05). The time needed for vesicourethral anastomosis remained unchanged throughout the study (average 48.5 minutes). CONCLUSIONS: With experience, the operative times for defined components of LRP improve. Patient selection for a low body mass index and smaller prostate may expedite the procedure. Application of a fixed retractor system, early identification of the vas deferens beneath the peritoneum in a more lateral position, and slow meticulous dissection and ligation of the dorsal vein complex are factors that may expedite the learning curve for LRP.

Comparison of second-generation hand-assisted laparoscopic devices for surgeon pain and arm circulation.

OBJECTIVES: To compare two second-generation hand-assist devices (HADs) for surgeon pain and manual blood flow over time in an in vitro model. METHODS: Nineteen participants placed their nondominant hand through both the LapDisc and GelPort into a pneumoperitoneum chamber with an insufflation pressure of 15 mm Hg for a 2-hour test period. Pain, on a 10-point visual analog scale, and manual blood flow to the index finger using a laser Doppler skin probe were measured at 10 points during the 2 hours. Participants completed a questionnaire regarding hand comfort and the physical effects of the HAD. RESULTS: At 30, 45, and 60 minutes after hand insertion, the pain scores were significantly greater for the GelPort than for the LapDisc (P = 0.04, P = 0.01, and P = 0.03, respectively). The GelPort caused an immediate reduction in manual blood flow, and the LapDisc caused a small initial increase in manual blood flow (P = 0.03) and, thereafter, a decrease in blood flow. Three participants voluntarily removed their hand at 30, 45, and 60 minutes owing to the pain from GelPort use. No participant withdrew from the LapDisc because of pain. CONCLUSIONS: Both HADs resulted in surgeon discomfort in our in vitro model. The GelPort resulted in more subjective pain compared with the LapDisc. Both HADs caused a reduction in manual blood flow. However, compared with the LapDisc, the GelPort caused significantly more reduction in manual blood flow. Surgeon comfort is only one parameter to consider when choosing a HAD.

Comparison of optical resolution with digital and standard fiberoptic cystoscopes in an in vitro model.

OBJECTIVES: To compare two different distal sensor flexible endoscopes with standard fiberoptic cystoscopes for optical resolution. Distal video sensor flexible endoscopy may represent the cusp of a new endoscopic revolution. METHODS: Twenty-three participants evaluated the optical resolution capabilities of six flexible cystoscopes. The two presently available distal sensor flexible cystoscopes, ACMI DCN-2010 digital flexible cystoscope and Olympus CYF-V EndoEYE flexible video cystoscope, were compared with the four leading fiberoptic cystoscopes, ACMI ACN-2 fiberoptic cystoscope, Olympus CYF-4 Cystofiberscope, Karl Storz 11272CU1 Flexible Cystoscope, and Richard Wolf Flexible Fibre Urethro-Cystoscope, in an in vitro model. The participants recorded the numerical digits they were able to visualize through five solutions with progressively increasing concentrations of hematoxylin dye (C1 to C5). The cystoscopic images were viewed on a 13-in. medical grade Olympus monitor with an Olympus Visera camera system. RESULTS: No differences were detected among the cystoscopes at the lowest concentrations of hematoxylin dye (C1 and C2). At C3 to C5, the mean percentage of visualized numbers for the ACMI and Olympus distal sensor flexible cystoscopes was significantly greater than for all fiberoptic cystoscopes (P <0.01). At the highest concentration (C5), the ACMI distal sensor cystoscope performed significantly better than did the Olympus distal sensor flexible cystoscopes (P <0.01), although at all other concentrations, the two digital video cystoscopes performed equivalently. CONCLUSIONS: The results of this in vitro study suggest that cystoscopes with distal sensor technology improve visibility in a simulated challenging working environment compared with fiberoptic cystoscopes.

Evaluation of intra-abdominal pressures and gas embolism during laparoscopic partial nephrectomy in a porcine model.

PURPOSE: Gas embolization is a well documented complication of laparoscopic surgery. We evaluated the association of gas embolization with increased intra-abdominal pressure (IAP) in the porcine model during laparoscopic partial nephrectomy with real-time transesophageal echocardiography. MATERIALS AND METHODS: Eight domestic pigs weighing 143 to 162 pounds underwent unilateral transperitoneal laparoscopic heminephrectomy with renal artery clamping with varied IAPs. The renal vein was not clamped, allowing the exposure of venous tributaries to the pneumoperitoneum. IAP was increased in 5 mm Hg increments in 4 pigs each by 1) insufflation pressure adjustment to a maximum of 30 mm Hg and 2) intermittent application of an argon beam coagulator (ABC) to the cut kidney surface. Transesophageal echocardiography was used to monitor embolism. RESULTS: None of the 4 animals subjected to increased CO2 insufflation pressure (maximum 30 mm Hg) demonstrated gas embolization during partial nephrectomy. The ABC caused gas embolization during partial nephrectomy at an IAP of 30 to 50 mm Hg in 4 animals. The volume of embolized gas was 4 to 20 ml. None of the animals showed intraoperative hemodynamic compromise. CONCLUSIONS: Gas embolization was not seen during laparoscopic partial nephrectomy with typical insufflation pressures. The ABC can rapidly increase IAP and cause argon embolization at IAPs greater than 30 mm Hg. Prophylactic maneuvers to prevent gas embolization, such as intra-abdominal venting or renal vein clamping, should be considered when applying the ABC.