Biomedical subjects

Jaime Landman

Publications and source records attributed to Jaime Landman.

At least 19 recordsLinked to original sources

PubMed2006

Comparison of laparoscopic partial nephrectomy and laparoscopic cryoablation for renal hilar tumors.

OBJECTIVES: To compare laparoscopic partial nephrectomy (LPN) and laparoscopic cryoablation (LC) for the management of small renal tumors located near the renal hilum. METHODS: A retrospective chart review was performed on all patients who underwent LPN and LC. A total of 23 patients (12 LPN and 11 LC) had tumors located within 5 mm of the renal hilar vasculature. Patient data were retrospectively analyzed for specific parameters, including operative time, efficacy, morbidity, and postoperative course. RESULTS: All 23 cases were successfully completed laparoscopically. The mean operative time for LPN and LC was 2.8 hours and 2.3 hours, respectively (P = 0.03). The mean estimated blood loss was 197 mL for LPN and 70 mL for LC (P < 0.01). The analgesic requirement for those undergoing LPN and LC was 29 mg morphine equivalent and 23 mg morphine equivalent, respectively (P = 0.41). The hospital stay for patients in the LPN and LC groups was 3.9 days and 3.2 days respectively (P = 0.55). No intraoperative complications occurred in either group. Six patients experienced nine complications in the LPN group. The complications included hemorrhage in 1, fever in 1, ileus in 1, urinary tract infection in 1, urine leak in 4, and transient postoperative neuropathy in 1. The LC group had no postoperative complications. In the LC cohort, no disease recurrence developed during the 11.3 months of follow-up. No positive margins were found in the LPN cohort, and with a mean follow-up of 12 months, none have developed recurrence. CONCLUSIONS: LPN for hilar tumors is a reasonable surgical option but carries an increased risk of urine leak. LC for hilar tumors has a shorter operative time and results in significantly fewer postoperative complications. Long-term follow-up data for both techniques remain unavailable.

Aged↗

PubMed2006

Evolution of surgical technique and patient outcomes for laparoscopic partial nephrectomy.

OBJECTIVES: To review the operative technique, complication rates, and short-term oncologic efficacy of the first 60 laparoscopic partial nephrectomies performed by a single surgeon and to report changes in our technique and the associated outcomes. METHODS: Between January 2002 and December 2004, data regarding patient characteristics, intraoperative technique, and outcome of 60 consecutive patients undergoing laparoscopic partial nephrectomy were prospectively collected. RESULTS: All 60 procedures were successfully completed laparoscopically without conversion to an open or hand-assisted approach. Histopathologic examination revealed renal cell carcinoma in 60% of patients with no positive margins or recurrences at a mean follow-up of 25.3 months. The overall complication rate was 30.0%, with 8 urologic (13.3%) and 10 nonurologic (16.7%) complications. CONCLUSIONS: With experience, laparoscopic partial nephrectomy is a viable alternative to open partial nephrectomy for small renal masses. At present, energy technologies and surgical pharmaceuticals are helpful adjuncts, but are not reliable for primary hemostasis and collecting system closure. Adaptation of traditional open techniques, including vascular control, excision of the tumor with cold scissors, and suture reconstruction of the collecting system and parenchyma, remain necessary to consistently perform laparoscopic partial nephrectomy successfully.

Adult↗

PubMed2006

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.

Clinical Competence↗

PubMed2006

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.

Alloys↗

PubMed2005

Complex laparoscopic partial nephrectomy for renal hilar tumors.

OBJECTIVES: To evaluate our experience with laparoscopic partial nephrectomy (LPN) for tumors located adjacent to the renal hilum. Continued advances in laparoscopic technology and technique have made LPN feasible for increasingly anatomically complex tumors. METHODS: A retrospective chart review was performed of all patients who underwent LPN at Washington University. We identified 8 patients who had undergone LPN between December 2001 and September 2004 for hilar tumors that were defined as those located within 5 mm of the renal hilar vessels. The data were retrospectively analyzed for parameters, including operative time, morbidity, and postoperative course. RESULTS: LPN was successfully completed in all 8 patients without conversion to an open or hand-assisted approach. The indication for nephron-sparing surgery was elective in 6 patients and imperative in 2. The mean operative time was 3.0 hours (range 2.5 to 3.5), and the mean estimated blood loss was 188 mL (range 30 to 700). All patients had negative margins on the final pathologic examination. No intraoperative complications occurred. Nine postoperative complications developed in 6 patients. They included hemorrhage in 1, fever in 1, ileus in 1, urinary tract infection in 1, urine leak in 4, and transient postoperative neuropathy in 1 patient. CONCLUSIONS: With adequate laparoscopic experience, LPN for hilar tumors is a reasonable surgical option. In our experience, the procedure was associated with an increased risk of urine leak. Preoperative placement of a ureteral catheter to help delineate collecting system violations and routine postoperative stenting may reduce the incidence of this complication.

Adult↗

PubMed2005

Single-setting bilateral laparoscopic renal surgery: assessment of single-stage procedure.

OBJECTIVES: To assess the safety and efficacy of single-setting bilateral laparoscopic renal procedures. The continued advancement of laparoscopic surgical technology and surgeon expertise has allowed increasingly technically challenging procedures to be completed laparoscopically. Little has been reported on patient outcome, morbidity, and mortality of bilateral laparoscopic single-stage procedures. METHODS: Between May 2000 and February 2004, 13 patients underwent synchronous bilateral renal surgery. Both retroperitoneal (n = 5) and transperitoneal (n = 8) approaches were used. The data were retrospectively analyzed for operative time, morbidity, mortality, and postoperative course. RESULTS: Bilateral laparoscopic procedures were successfully completed in 11 (85%) of 13 patients. One patient required conversion to an open procedure because of significant adhesions. Another patient with von Hippel-Lindau disease had unexpected extensive pathologic features in each kidney and was therefore treated in a staged fashion. The mean operative time was 5.5 hours (range 4.7 to 8.5). The mean estimated blood loss was 268 mL (range 50 to 950). Patients resumed oral intake and ambulated within 24 hours after surgery. The mean analgesic requirement was 40.5 mg MSO4 equivalents (range 2 to 178). The mean hospital stay was 3.1 days (range 1 to 6). Patients returned to partial activity within the first week and enjoyed full activity at 3 weeks. One intraoperative complication and five postoperative complications occurred in 5 patients. CONCLUSIONS: Our results have demonstrated that single-setting bilateral laparoscopic renal surgery is safe and can expedite resolution of urologic pathologic findings without increased morbidity. Bilateral single-setting laparoscopic surgery should only be performed if the primary procedure has been completed expeditiously and without complications.

Adolescent↗

PubMed2005

Development of exophytic tumor model for laparoscopic partial nephrectomy: technique and initial experience.

OBJECTIVES: To develop and test a porcine model to help teach the techniques needed to perform laparoscopic partial nephrectomy (LPN), which is a technically challenging procedure with necessary reconstructive skills that are difficult to transfer. METHODS: A tumor model was created by unilateral subcapsular percutaneous injection of liquid plastic (Smooth-Cast 320) in five pig kidneys. Five Washington University urologists performed LPN and assessed the efficacy of the tumor model. Subsequently, the tumor model was evaluated as a tool for teaching LPN during the Washington University Advanced Laparoscopic and Robotic Urologic Oncology Course. Twenty-eight participants performed unilateral porcine LPN with the tumor model. Questionnaires were used to assess the utility of this tumor model. RESULTS: Unilateral tumors were successfully created in five pigs and remained intact during all LPN procedures. Visually, the tumors appeared as white exophytic masses. Ultrasonography revealed a well-circumscribed, hypoechoic lesion and a mean diameter of 2.02 cm. The mean operative time was 32.4 minutes. In subsequent testing, 24 (86%) of the 28 participants returned the questionnaire, and 96% responded that the tumor model had enhanced their LPN learning experience. Seven course participants (29%) reported problems with hemostasis, ultrasonography, or laparoscopic instrumentation. Two tumor model-related complications occurred. During the initial evaluation, one pig experienced a fatal pulmonary embolism of the plastic. During the course, a second animal experienced extravasation of the solution into the renal collecting system. CONCLUSIONS: For surgical education purposes, the Smooth-Cast model is an effective surgical tool for LPN. Most of the surgeons in this evaluation believed the model enhanced their learning experience.

Animals↗

PubMed2005

Laparoscopic renal parenchymal hypothermia with novel ice-slush deployment mechanism.

OBJECTIVES: To report the development of a novel, simple-to-use method for laparoscopic deployment of fine-quality saline ice slush by way of a 10-mm end-effector for laparoscopic parenchymal hypothermia. METHODS: A mechanism for making fine ice slush was created, and a 10-mm laparoscopic end-effector was designed and constructed for deployment of the ice slush. The novel ice slush deployment system was tested in a porcine model and compared with that of standard open ice slush cooling. After atraumatic hilar clamping, the cortical and medullary temperatures in the upper, middle, and lower poles were measured with thermocouples. RESULTS: Six pigs were evaluated in each group. In all cases, the kidneys were successfully cooled to our goal temperature of 15 degrees to 25 degrees C within 10 minutes and were maintained at the target temperature for 1 hour. The core body temperature for the slush group was decreased by 3 degrees C but did not change in the open group. The renal temperatures quickly returned to normal on unclamping of the renal hilum. One pig in the open group died of acidosis and another in the same group experienced thrombosis of the renal artery. No complications occurred in the laparoscopic group. CONCLUSIONS: We describe a novel, simple-to-use mechanism for producing and delivering fine ice slush in a laparoscopic setting. The technique achieves optimal parenchymal hypothermia expeditiously.

Animals↗

PubMed2005

Evaluation of surgical models for renal collecting system closure during laparoscopic partial nephrectomy.

OBJECTIVES: To evaluate the utility of the porcine and canine models for collecting system closure after partial nephrectomy involving violation of the renal collecting system. Advanced surgical technologies and novel techniques for performing laparoscopic partial nephrectomy are frequently evaluated in an animal model. METHODS: After evaluation of the upper urinary tract with retrograde pyelography, laparoscopic partial nephrectomy, including violation of the renal collecting system, was performed in 8 domestic pigs (group 1) and 2 dogs (group 2) with documented normal upper urinary tract physiology. No collecting system closure was performed. Subsequently, in an attempt to generate an adequate model for renal collecting system closure, 6 pigs (group 3) underwent partial obstruction of the proximal ureter before laparoscopic partial nephrectomy without collecting system closure. After 3 weeks, the animals underwent evaluation, including retrograde pyelography, and were killed for histopathologic evaluation of the upper urinary tracts. RESULTS: Despite documented transection of major calices in all animals, none with physiologically normal upper urinary tracts developed urinomas. After partial occlusion of the proximal ureter, all pigs had hydronephrosis, but only one of six developed a urinoma. CONCLUSIONS: The porcine and canine models are inadequate for evaluating renal collecting system closure after partial nephrectomy. Our high-pressure partial occlusion model was similarly inadequate. The limitations of these animal models should be considered when reviewing published data regarding technologies for partial nephrectomy. Future data regarding novel technologies for partial nephrectomy should also be carefully considered before clinical application.

Animals↗

PubMed2005

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.

Cystoscopes↗

PubMed2005

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.

Clinical Competence↗

PubMed2005

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.

Cadaver↗

PubMed2005

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.

Arm↗

PubMed2005

Laparoscopic renal surgery and the risk of rhabdomyolysis: diagnosis and treatment.

Postoperative rhabdomyolysis is a rare but serious complication of laparoscopic renal urologic surgery. The early recognition and treatment of the condition are imperative to minimize the risk of acute renal failure (ARF) and to limit the associated physical debility. Between 1992 and 2003, > 700 laparoscopic renal procedures were performed at 2 institutions. Rhabdomyolysis occurred in 7 patients. Patient records were retrospectively analyzed for operative, postoperative, and convalescence data. Rhabdomyolysis presented in all patients as excessive, immediate postoperative muscular pain in the "downside" hip/flank. The average procedure time among these patients was 7.5 hours (range, 5.8 to 9.4 hours). In 6 of 7 cases, the kidney rest was elevated throughout the procedure. Two patients required emergency fasciotomy to treat a gluteal compartment syndrome. Four patients (57%) experienced ARF with an average peak creatinine of 533.8 micromol/L [7.0 mg/dL] (range, 160.1 to 739.6 micromol/L [2.1 to 9.7 mg/dL]). These patients had bicarbonate alkalinization and diuretic administration initiated at a mean of 24 hours (range, 4 to 48 hours). Two patients required hemodialysis for 1 month postoperatively but had stable serum creatinine (106.8 and 129.6 micromol/L [1.4 and 1.7 mg/dL]) within 2 months. The mean peak serum creatinine kinase (CK) for all patients was 33,912 U/L (range, 9350 to 99,193 U/L). All patients had extended recovery with difficulties including lower extremity weakness (n = 4), local pressure neuropathy (n = 1), long-term leg pain and numbness (n = 1), and disability requiring long-term wheelchair assistance (n = 1). Excessive, immediate postlaparoscopic gluteal muscular pain should prompt immediate evaluation of serum CK to assess for rhabdomyolysis. Aggressive hydration and diuresis are recommended to minimize renal injury. Minimizing operative times, attention to padding of the operative table, and eliminating or limiting the use of a kidney rest may help prevent this complication.

Humans↗

PubMed2005

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.

Anastomosis, Surgical↗

PubMed2005

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.

Animals↗

PubMed2005

Impact of a double-pigtail stent on ureteral peristalsis in the porcine model: initial studies using a novel implantable magnetic sensor.

BACKGROUND AND PURPOSE: The effect of stents on ureteral peristalsis in vivo is not entirely clear. We sought to develop a minimally invasive method for its study. MATERIALS AND METHODS: In female domestic pigs, electrical potentials from the ureter were measured by bipolar steel-wire electromyography electrodes delivered laparoscopically. Mechanical movement was measured by giant magneto resistive sensors mounted on custom-made aluminum strips. After baseline values were obtained, the animals were randomized to receive silicone or polyurethane stents, and ureteral peristalsis was measured for 8 hours acutely and for 4 hours 1 week later. RESULTS: Implantation of the devices took an average of 30 minutes. A consistent correlation was found between laparoscopically observed peristaltic waves and the peristalsis detected by the two measuring devices. The devices themselves did not affect peristalsis. Stent insertion increased peristaltic activity initially but later reduced or stopped it. There was no difference in the effects of the two types of stents. CONCLUSIONS: The new technique permits close monitoring of ureteral peristalsis in vivo. Smaller stents appear to have less immediate effect than larger ones, but all type of stents tested eventually caused aperistalsis.

Animals↗

PubMed2005

Comparison of a novel endoscope holder and traditional camera assistant for laparoscopic simple nephrectomy in a porcine model.

PURPOSE: To establish the feasibility of single-surgeon laparoscopy with application of a novel endoscope-holder device and to compare this technique with traditional assistant-driven laparoscopic camera control. MATERIALS AND METHODS: Bilateral simple nephrectomies were performed in six pigs. On one side, the operating surgeon employed the "scope holder" and performed the surgery without a laparoscopic assistant. On the contralateral side, an experienced camera operator was responsible for control of the laparoscopic field of vision in the traditional manner. The time required for hilar ligation and complete renal mobilization was documented. Pigs were sacrificed immediately after the procedure. RESULTS: The mean operative times for scope-holder and camera person-assisted nephrectomy were 20.7 minutes and 19.3 minutes, respectively. The time to hilar ligation in the scope-holder and camera-operator-assisted cohorts was 13 and 14.5 minutes, respectively. There were no significant differences in operative times or blood loss in the two groups. The operative surgeon perceived some increase in shoulder and neck pain with use of the scope holder. CONCLUSIONS: This novel device provides a means for the operative surgeon to safely perform a laparoscopic nephrectomy alone without significantly increasing operative time or morbidity.

Animals↗