Evaluation of a Chitosan Hemostat in a Porcine Laparoscopic Partial Nephrectomy Model: A Pilot Study.

Background and Objective: The ideal hemostatic agent for laparoscopic partial nephrectomy (LPN) would provide complete hemostasis and sealing of the collecting system at a low cost. Chitosan (CS) is an established topical hemostatic agent, but standard sterilization techniques affect its functional and biologic properties, thereby preventing parenteral uses. This study sought to characterize the safety and efficacy of an implanted CS hemostat sterilized with either a standard technique, electron beam (e-beam) irradiation, or a novel technique, nonthermal nitrogen plasma, in a porcine LPN model. Methods: Laparoscopic partial nephrectomies were performed on six farm pigs and hemostasis achieved using only a CS hemostatic agent (Clo-Sur P.A.D.) that was e-beam (n = 3) or plasma sterilized (PS) (n = 3). Number of pads needed to achieve hemostasis, estimated blood loss, operative time, mass of kidney resection, and warm ischemia time were measured. Animals were monitored for 14 weeks and at harvest, retrograde ureteropyelography and histologic analysis were performed. Results: Complete hemostasis and collection system sealing were achieved in both groups. There was a trend toward less pads required for hemostasis (p = 0.056) and reduced blood loss (p = 0.096) with PS pads, although this did not achieve statistical significance. No complications were observed for 14 weeks and gross examination showed the implanted CS was encapsulated in a fibrous capsule. Histologic analysis revealed a healed nephrectomy site with residual CS and associated chronic inflammation, reactive fibrosis, and foreign body giant cell formation. Importantly, the adjacent renal tissue was intact and viable with no residual parenchymal inflammation or cytologic damage. Conclusion: CS pads alone provided safe and effective hemostasis in a porcine LPN model. PS may enhance hemostatic efficacy and resorption compared with e-beam.

Applying translabial ultrasound to detect synthetic slings-You can do it too! A comparison of urology trainees to an attending radiologist.

AIMS: Translabial ultrasound (TUS) is a useful tool for identifying and assessing synthetic slings. This study evaluates the ability of urology trainees to learn basic pelvic anatomy and sling assessment on TUS. METHODS: Eight urology trainees (six residents and two medical students) received a lecture reviewing basic anatomy and sling assessment on TUS followed by review of two training cases. Next, they underwent a 126-question examination assessing their ability to identify anatomic planes and structures in those planes, identify the presence of slings, and assess the location and intactness of a sling. The correct response rate was compared to that of an attending radiologist experienced in reading TUS. Non-parametric tests (Fisher's exact, chi-squared tests, and Yates correction) were used for statistical analysis, with P < 0.05 considered significant. RESULTS: 847/1008 (84.0%) of questions were answered correctly by eight trainees compared to 119/126 (94.4%) by the radiologist (P = 0.001). The trainees' correct response rates and Fisher's exact test P values associated with the difference in correct answers between radiologist and trainee were as follows: identification of anatomic plane (94.4%; P = 0.599), identification of structure in sagittal view (80.6%; P = 0.201), identification of structure in transverse view (88.2%; P = 0.696), presence of synthetic sling (95.8%; P = 1.000), location of sling along the urethra in (71.5%; P = 0.403), intactness of sling (82.6%; P = 0.311), and laterality of sling disruption (75.0%; P = 0.076). CONCLUSIONS: Urology trainees can quickly learn to identify anatomic landmarks and assess slings on TUS with reasonable proficiency compared to an experienced attending radiologist.

Percutaneous Externally Assembled Laparoscopic vs Laparoendoscopic Single-Site Nephrectomy in a Porcine Model: A Prospective, Randomized, Blinded, Study.

OBJECTIVE: To compare the outcomes between laparoendoscopic single-site (LESS) and a novel percutaneous externally assembled laparoscopic (PEAL) nephrectomy in an in vivo porcine model. MATERIALS AND METHODS: Ten female farm pigs were randomized to LESS nephrectomy (5) or PEAL nephrectomy (5). Operative times, estimated blood loss, and intraoperative and postoperative complications were compared. The surgeons used a Likert scale to grade difficulty of peritoneal access, port placement, tool assembly, hilar dissection, closure, and overall difficulty of surgery. Scar assessment was performed by a blinded plastic surgeon using the Vancouver Scar Scale. Descriptive statistics were reported as median and range. The Mann-Whitney U test was used for continuous and ordinal variables. A p value <0.05 was considered significant. RESULTS: Median operative time was significantly shorter in the PEAL group vs the LESS group (85 minutes vs 127 minutes, p = 0.03). Median Likert scores showed overall hilar dissection and nephrectomy to be significantly easier using PEAL compared with LESS (2 vs 9, p < 0.01 for both). The PEAL instruments left no visible scar at 5 feet in any animal, and only 1 out of 10 scars could be identified on physical examination. CONCLUSIONS: The PEAL surgical paradigm demonstrates nearly scarless outcomes while providing shorter operative times and easier performance than LESS nephrectomy in a porcine model.

The Impact of Operating Room Noise Upon Communication During Percutaneous Nephrostolithotomy.

OBJECTIVE: Equipment and personnel contribute to the overall noise level in the operating room (OR). This study aims to determine intraoperative noise levels during percutaneous nephrostolithotomy (PCNL) and the effects of this noise upon intraoperative communication. METHODS: A PCNL benchtop model was used to measure intraoperative noise and determine its effect upon communication in three progressively increasing sound environments (baseline ambient noise, ambient noise with PCNL equipment, and ambient noise with both PCNL equipment and music). Five trials with 20 different medical words/phrases were spoken by the surgeon and responses were recorded by the first assistant, anesthesiologist, and circulating nurse. In addition, noise levels during PCNL were compared to common environmental noise levels. RESULTS: In the bench top model, noise levels were 53.49 A-weighted decibels (dBA) with ambient noise, 78.79 dBA with equipment in use, and 81.78 dBA with equipment and music. At the ambient noise level, the first assistant, anesthesiologist, and circulator correctly recorded 100%, 100%, and 96% of the words, respectively. The correct response rate by the subjects decreased to 97% (p = 0.208), 81% (p = 0.012), and 56% (p < 0.001) upon addition of PCNL equipment, and 90% (p = 0.022), 48% (p = 0.002), and 13% (p < 0.001) upon addition of music and PCNL equipment in the first assistant, anesthesiologist, and circulator, respectively. In the simulated OR model, PCNL noise level (81.78 dBA) was comparable to a passing freight train at 30 feet (82.2 dBA, p = 0.44). CONCLUSION: Noise pollution decreases effective intraoperative communication during PCNL. It is important for surgeons to understand the effect noise can have on attempted communication to prevent errors due to miscommunication. In addition, methods to decrease intraoperative noise pollution and improve communication in the OR could improve patient safety and outcomes.

Direct Endoscopic Visualization Combined with Ultrasound Guided Access during Percutaneous Nephrolithotomy: A Feasibility Study and Comparison to a Conventional Cohort.

PURPOSE: Percutaneous nephrolithotomy access may be technically challenging and result in significant radiation exposure. In an attempt to reduce percutaneous nephrolithotomy radiation exposure, a novel technique combining ultrasound and direct ureteroscopic visualization was developed and reviewed. MATERIALS AND METHODS: Ureteroscopy without fluoroscopy was used to determine the optimal calyx for access, which was punctured with a Chiba needle under percutaneous ultrasound guidance. Next a wire was passed into the collecting system and ureteroscopically pulled into the ureter using a basket. Tract dilation and sheath and nephrostomy tube placement were performed under direct ureteroscopic visualization. Twenty consecutive patients undergoing this novel technique were reviewed and compared to 20 matched patients treated with conventional percutaneous nephrolithotomy. Mann-Whitney U and Pearson chi-square tests were used for comparisons with p <0.05 considered significant. RESULTS: Using this novel technique mean fluoroscopy access time was 3.5 seconds (range 0 to 27.9) and mean total fluoroscopic time was 8.8 seconds (range 0 to 47.1). Mean operative time was 232 minutes (range 87 to 533), estimated blood loss was 111 ml, the stone-free rate was 65% and the complication rate was 25%. Compared to 20 matched conventional percutaneous nephrolithotomy cases, there was no difference in operative time (p=0.76), estimated blood loss (p=0.64), stone-free rate (p=0.50) or complications (p=1.00). However, the novel technique resulted in a significant reduction in fluoroscopy access time (3.5 vs 915.5 seconds, p <0.001) and total fluoroscopy time (8.8 vs 1,028.7 seconds, p <0.001). CONCLUSIONS: This study demonstrates the feasibility of combined ultrasound and ureteroscopic assisted access for percutaneous nephrolithotomy. A greater than 99% reduction in fluoroscopy time was achieved using this technique.

The Effect of Laser Fiber Cleave Technique and Lithotripsy Time on Power Output.

PURPOSE: Various cleave techniques have recently been shown to significantly impact initial laser fiber power output during holmium laser lithotripsy. The impact of cleave technique on long-term power output has not been well characterized. The purpose of this study was to determine the effect of laser cleave technique on power output over time. MATERIALS AND METHODS: In this randomized single-blinded study, five cleave techniques were tested on two holmium laser fiber diameters (200, 365 µm) over 15 minutes of laser lithotripsy with calcium oxalate monohydrate stones. Comparisons between cleave techniques and fiber diameters were performed using independent samples Mann-Whitney U, Kruskal-Wallis, and homogeneity of variance tests with a significance of p < 0.05. RESULTS: The 365-µm fiber was more durable and less affected by burnback degradation than the 200-µm fiber (p < 0.05). While initial power output varied between cleave techniques, all significance disappeared by 3 minutes. Power output decreased rapidly by a mean of 0.62 W over 4 minutes (p < 0.05), following which there was no significant change. CONCLUSION: These findings confirm that initial laser fiber power output is significantly influenced by cleave technique, and the ceramic scissor is the optimal tool for cleaving between procedures. However, because of rapid fiber tip degradation and power loss, this study argues against routine cleaving to improve procedural efficiency in lengthy ureteroscopy cases.

Percutaneous Externally Assembled Laparoscopic Instruments: Creation of a New Surgical Paradigm.

OBJECTIVES: Laparoendoscopic single-site surgery (LESS) and natural orifice transluminal endoscopic surgery (NOTES) produce excellent cosmetic outcomes, but are technically challenging. The objective of this study was to test the functionality and feasibility of a novel minimally invasive surgical paradigm, which maintains triangulation but uses special externally assembled instruments to minimize the postoperative cosmetic impact. METHODS: Percutaneous Externally Assembled Laparoscopic (PEAL) instruments have specialized 2.96-mm shafts with interchangeable 5-mm working tips that are assembled externally. First, 5-mm laparoscopic, PEAL, and 2-mm needlescopic instruments were tested to determine piercing force on fresh human cadaver organs. In a bench-top study, 20 subjects assembled and used PEAL instruments in five different skills tests that were also compared with the same tasks using conventional laparoscopic instruments. Finally, PEAL instrument functionality was tested in a four-porcine nephrectomy feasibility study. RESULTS: PEAL (2.80 lbF) and 5-mm laparoscopic instruments (2.28 lbF) had a significantly higher mean organ piercing perforation force compared with needlescopic instruments (1.39 lbF, p < 0.05). Average assembly time of PEAL instruments was 31.08 seconds (range: 19.83-43.85). There were no significant differences in the amount of time needed for completion of the bench-top tasks between laparoscopic and PEAL instruments (p > 0.05 for all tasks). Four-porcine PEAL nephrectomies were completed with no complications and minimal blood loss (mean 7.5 mL). Mean operative time was 98.25 minutes (range 79-116). CONCLUSION: PEAL tools are easily assembled, have similar safety and efficacy compared with standard laparoscopic tools, and are less likely to injure organs compared with needlescopic instruments. They function well during laparoscopic nephrectomy and may decrease the invasiveness of conventional laparoscopic instrumentation.

Renal Vascular Clamp Placement: A Potential Cause of Incomplete Hilar Control during Partial Nephrectomy.

PURPOSE: Previous benchtop studies have shown that robotic bulldog clamps provide incomplete vascular control of a Penrose drain. We determined the efficacy of robotic and laparoscopic bulldog clamps to ensure hemostasis on the human renal artery. The effect of clamp position on vascular control was also examined. MATERIALS AND METHODS: Fresh human cadaveric renal arteries were used to determine the leak point pressure of 7 bulldog clamps from a total of 3 manufacturers. Five trials were performed per clamp at 4 locations, including the fulcrum, proximal, middle and distal positions. Comparison was done using the Kruskal-Wallis test with p <0.05 considered significant. RESULTS: None of the bulldog clamps leaked at a pressure less than 215 mm Hg when applied at the proximal, middle or distal position. In general leak point pressure decreased as the artery was positioned more distal along the clamp. The exception was when the vessel was placed at the fulcrum position. At that position 80% to 100% of trials with the Klein laparoscopic, 100% with the Klein robotic (Klein Robotic, San Antonio, Texas) and 60% to 80% with the Scanlan robotic (Scanlan International, Saint Paul, Minnesota) clamp leaked at pressure below 215 mm Hg. CONCLUSIONS: Each vascular clamp adequately occluded flow at physiological pressure when placed at the proximal, middle or distal position. Furthermore, these results demonstrate that there is leakage at physiological pressure when the artery is placed at the fulcrum of certain clamp types. These results suggest that applying a bulldog clamp at the fulcrum could potentially lead to inadequate vessel occlusion and intraoperative bleeding.