Does allowing for changes of mind influence initial responses?

Evidence accumulation models (EAMs) have become the dominant theoretical framework for rapid decision-making, and while many theoretically distinct variants exist, comparisons have proved challenging due to strong mimicry in their predictions about choice response time data. One solution to reduce mimicry is constraining these models with double responses, which are a second response that is made after the initial response. However, instructing participants that they are allowed to change their mind could influence their strategy for initial responding, meaning that explicit double responding paradigms may not generalise to standard paradigms. Here, we provide a validation of explicit double responding paradigms, by assessing whether participants' initial decisions - as measured by diffusion model parameters - differ based on whether or not they were instructed that they could change their response after their initial response. Across three experiments, our results consistently indicate that allowing for changes of mind does not influence initial responses, with Bayesian analyses providing at least moderate evidence in favour of the null in all cases. Our findings suggest that explicit double responding paradigms should generalise to standard paradigms, validating the use of explicit double responding in future rapid decision-making studies.

Evaluation of Feed Near-Infrared Reflectance Spectra as Predictors of Methane Emissions from Ruminants.

Feed chemical composition is associated with methane (CH4) formation in the rumen, and thus CH4 yields (Ym; CH4 emitted from per unit of dry matter intake) could be predicted using near-infrared reflectance spectroscopy (NIRS) of feeds fed to ruminants. Two databases of NIRS data were compiled from feeds used in experiments in which CH4 yields had been quantified in respiration chambers. Each record in the databases represented a batch of feed offered to a group of experimental animals and the mean CH4 yield for the group. A near-infrared reflectance spectrum was obtained from each feed, and these spectra were used to generate a predictive equation for Ym. The predictive model generated from brassica crops and pasture fed at a similar feeding level (n = 40 records) explained 53% of the variation in Ym and had a reasonably good agreement (concordance correlation coefficient of 0.77). The predictive ability of the NIRS calibration could be useful for screening purposes, particularly for predicting the potential Ym of multiple feeds or feed samples, rather than measuring Ym in animal experiments at high expenses. It is recommended that the databases for NIRS calibrations are expanded by collecting feed information from future experiments in which methane emissions are measured, using alternative algorithms and combining other techniques, such as terahertz time-domain spectroscopy.

Understanding Performance Decrements in a Letter-Canceling Task: Overcoming Habits or Inhibition of Reading.

The importance of self-regulation in human behavior is readily apparent and diverse theoretical accounts for explaining self-regulation failures have been proposed. Typically, these accounts are based on a sequential task methodology where an initial task is presented to deplete self-regulatory resources, and carryover effects are then examined on a second outcome task. In the aftermath of high profile replication failures using a popular letter-crossing task as a means of depleting self-regulatory resources and subsequent criticisms of that task, current research into self-control is currently at an impasse. This is largely due to the lack of empirical research that tests explicit assumptions regarding the initial task. One such untested assumption is that for resource depletion to occur, the initial task must first establish an habitual response and then this habitual response must be inhibited, with behavioral inhibition being the causal factor in inducing depletion. This study reports on four experiments exploring performance on a letter-canceling task, where the rules for target identification remained constant but the method of responding differed (Experiment 1) and the coherence of the text was manipulated (Experiments 1-4). Experiment 1 established that habit forming and behavioral inhibition did not produce any performance decrement when the targets were embedded in random letter strings. Experiments 2-4 established that target detection was sensitive to language characteristics and the coherence of the background text, suggesting that participants' automatic reading processes is a key driver of performance in the letter-e task.

Evaluation of wearable simulation interface for military training.

OBJECTIVE: This research evaluated the training effectiveness of a novel simulation interface, a wearable computer integrated into a soldier's load-bearing equipment. BACKGROUND: Military teams often use game-based simulators on desktop computers to train squad-level procedures. A wearable computer interface that mimics the soldier's equipment was expected to provide better training through increased realism and immersion. METHOD: A heuristic usability evaluation and two experiments were conducted. Eight evaluators interacted with both wearable and desktop interfaces and completed a usability survey. The first experiment compared the training retention of the wearable interface with a desktop simulator and interactive training video. The second experiment compared the training transfer of the wearable and desktop simulators with a live training environment. RESULTS: Results indicated the wearable interface was more difficult to use and elicited stronger symptoms of simulator sickness. There was no significant difference in training retention between the wearable, desktop, or interactive video training methods. The live training used in the second experiment provided superior training transfer than the simulator conditions, with no difference between the desktop and wearable. CONCLUSION: The wearable simulator interface did not provide better training than the desktop computer interface. It also had poorer usability and caused worse simulator sickness. Therefore, it was a less effective training tool. APPLICATION: This research illustrates the importance of conducting empirical evaluations of novel training technologies. New and innovative technologies are always coveted by users, but new does not always guarantee improvement.

Extending the Collection Duration of Breath Samples for Enteric Methane Emission Estimation Using the SF6 Tracer Technique.

The daily sample collection protocol of the sulphur hexafluoride (SF6) tracer technique for the estimation of methane (CH4) emissions from ruminants may not be practical under extensive grazing systems. Here, under controlled conditions, we evaluated extended periods of sampling as an alternative to daily sample collections. Eight rumen-fistulated cows were housed and fed lucerne silage to achieve common daily feed intakes of 6.4 kg dry matter per cow. Following SF6 permeation tube dosing, eight sampling lines were fitted to the breath collection harness, so that a common gas mix was available to each line. Half of the lines collected samples into PVC yokes using a modified capillary system as commonly used in New Zealand (NZL), and half collected samples into stainless steel cylinders using a ball-bearing flow restrictor as used in Argentina (ARG), all within a 10-day time frame, either daily, across two consecutive 5-day periods or across one 10-day period (in duplicate). The NZL system had greater sampling success (97.3 vs. 79.5%) and yielded more consistent CH4 emission estimates than the ARG system. Emission estimates from NZL daily, NZL 5-day and NZL 10-day samplings were 114, 110 and 111 g d(-1), respectively. Extended sample collection protocol may be feasible, but definitive evaluation of this alternative as well as sample collection systems is required under grazing situations before a decision on recommendation can be made.

Individual differences in response to automation: the five factor model of personality.

This study examined the relationship of operator personality (Five Factor Model) and characteristics of the task and of adaptive automation (reliability and adaptiveness-whether the automation was well-matched to changes in task demand) to operator performance, workload, stress, and coping. This represents the first investigation of how the Five Factors relate to human response to automation. One-hundred-sixty-one college students experienced either 75% or 95% reliable automation provided with task loads of either two or four displays to be monitored. The task required threat detection in a simulated uninhabited ground vehicle (UGV) task. Task demand exerted the strongest influence on outcome variables. Automation characteristics did not directly impact workload or stress, but effects did emerge in the context of trait-task interactions that varied as a function of the dimension of workload and stress. The pattern of relationships of traits to dependent variables was generally moderated by at least one task factor. Neuroticism was related to poorer performance in some conditions, and all five traits were associated with at least one measure of workload and stress. Neuroticism generally predicted increased workload and stress and the other traits predicted decreased levels of these states. However, in the case of the relation of Extraversion and Agreeableness to Worry, Frustration, and avoidant coping, the direction of effects varied across task conditions. The results support incorporation of individual differences into automation design by identifying the relevant person characteristics and using the information to determine what functions to automate and the form and level of automation.

Training for renal ablative technique using an agarose-based renal tumour-mimic model.

OBJECTIVE: To assess whether a recently developed porcine tumour-mimic model can serve as a training model for radiofrequency ablation (RFA) of renal masses, as the increased diagnosis of small occult renal masses has led to the development of nephron-sparing treatments, including RFA, and the techniques required for effective tumour ablation can be difficult to master. MATERIALS AND METHODS: Tumour mimics were created by injecting 0.7 mL of an agarose mixture into the parenchyma of a porcine kidney, producing 1-cm spherical lesions which were hyperechoic on ultrasonography (US). The ex vivo experiment included creating 40 tumour mimics followed by RFA using US-guided needle placement. The ablation diameter was set to 15 mm to produce a margin of grossly ablated tissue around the mimic lesions. The in vivo portion involved creating 20 tumour mimics and ablating them under direct laparoscopic vision with US-guided probe placement. In each case, the mimic lesion size by US and gross examination, ablation diameter, and completion (accuracy) of ablations were recorded. RESULTS: Accurate placing of the RFA needle by US guidance was difficult to learn, as all tumour-mimic lesions were either endophytic or completely intraparenchymal. The ex vivo model required approximately 15 ablations before the needle was placed consistently into the lesions. The in vivo model was equally difficult to learn, with five positive margins by gross examination in the first 10 ablations, while the subsequent 10 had no positive margins. CONCLUSION: The agarose-based tumour mimic is a useful target model for learning and improving US-guided ablative techniques in both the ex vivo and in vivo settings. The tumour-mimic allows the surgeon to assess targeting accuracy in an animal model. Further studies are needed to determine this model's utility as a clinical training aid.

Cytokine response to surgical stress: comparison of pure laparoscopic, hand-assisted laparoscopic, and open nephrectomy.

BACKGROUND AND PURPOSE: Laparoscopic surgery has been shown to induce less immune suppression than open surgery, presumably because there is less tissue trauma, a factor that may impact oncologic-disease control. The objective of this study was to compare the cytokine and stress response associated with pure laparoscopic, hand-assisted laparoscopic (HAL), and open nephrectomy. MATERIAL AND METHODS: Fifteen female farm pigs (45-50 kg) underwent transperitoneal laparoscopic, handassisted (HAL), or open nephrectomy (N = 5 in each group). At 1, 4, 24, and 48 hours post-nephrectomy, blood and peritoneal fluid samples were collected for measurement of tumor necrosis factor (TNF) alpha, interleukin (IL)-1beta, and IL-6 using enzyme-linked immunosorbent assay (ELISA) techniques. Body temperature and serum glucose and cortisol were also measured. RESULTS: No evidence of perioperative infection was detected in any animal through temperature and glucose monitoring. Operating time and blood loss were comparable among the three groups. Peak serum cortisol concentrations were significantly higher in the HAL group than in the pure laparoscopic group at 24 hours (P = 0.02). Serum TFNalpha concentrations were significantly lower in the pure laparoscopy group (40 +/- 6 pg/mL) than in the HAL and open-nephrectomy groups (81 +/- 6 pg/mL and 83 +/- 17 pg/mL, respectively; P < 0.05), although no differences between groups were found in the serum IL-1beta and IL-6 concentrations. Peritoneal IL-1beta was significantly higher in the HAL than in the open-nephrectomy group (2993 +/- 507 pg/mL and 733 +/- 185 pg/mL, respectively; P = 0.05). Peritoneal IL-6 was significantly lower in the pure laparoscopy group (694 +/- 234 pg/mL) than in the open-surgery group (1668 +/- 312 pg/mL) (P = 0.04). CONCLUSION: Pure laparoscopic surgery in pigs elicits a less-robust cytokine response than HAL or open nephrectomy with respect to serum TNFalpha and peritoneal IL-6 concentrations, perhaps reflecting less impairment of the immune system. Clinical confirmation is required, and the implications with regard to oncologic tumor surveillance in humans require further study.

Hand-assisted laparoscopic nephrectomy for renal masses >9.5 cm: series comparison with open radical nephrectomy.

OBJECTIVE: To assess the feasibility of hand-assisted laparoscopic nephrectomy (HALN) for large renal masses (stage T2, mean size 9.7 cm) and compare outcomes with a similar cohort undergoing open radical nephrectomy (ORN). METHODS: A nonrandomized comparison of 19 consecutive patients who underwent nephrectomy for renal masses >or=7 cm was performed. The HALN group was compared to the ORN group regarding demographic parameters and perioperative data, including blood loss, operating time, narcotic usage, hematocrit change, return to standard oral intake, length of hospital stay, and complications. Data collected prospectively and statistics used 2-tailed t-test analysis. RESULTS: Patients underwent either ORN (mean tumor size 12.3 cm) or HALN (mean tumor size 9.7cm). Tumors up to 14 cm (n = 2) and pT3b, with renal vein thrombosis (n = 2), could be safely excised with HALN. There were no differences between the HALN and ORN groups regarding any demographic parameter. Blood loss, operating time, length of stay, parenteral narcotic use, and time to tolerating regular diet were all less statistically significant in the HALN group as compared to the ORN group (P < 0.05). Tumors >15 cm necessitated ORN. CONCLUSIONS: HALN is technically feasible even for tumors with mean size >9.5 cm. There is a significant advantage to HALN over ORN regarding the intraoperative and postoperative morbidity. Tumors >or=15 cm should, in most cases, be performed with an open approach.

Effect of warmed, humidified insufflation gas and anti-inflammatory agents on cytokine response to laparoscopic nephrectomy: porcine model.

PURPOSE: We evaluated the effects of warmed, humidified CO2 and anti-inflammatory agents on the local and systemic cytokine response after laparoscopic nephrectomy. MATERIALS AND METHODS: A total of 15 pigs were randomized to undergo standard laparoscopic nephrectomy, laparoscopic nephrectomy with warmed, humidified CO2 gas or laparoscopic nephrectomy with perioperative administration of intravenous dexamethasone and oral rofecoxib. At baseline, and 1, 4, 24 and 48 hours after surgery duplicate blood and peritoneal samples were drawn to analyze cortisol, glucose, tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta and IL-6 via a microassay technique. Body temperature was determined at operation, intraoperatively and 1 hour postoperatively. Surgical parameters, including operative time, gas volume used and blood loss, were recorded. RESULTS: Pigs in the warmed, humidified CO2 and anti-inflammatory arms maintained higher intraoperative and postoperative core body temperatures than controls. Warmed, humidified CO2 did not affect peritoneal or systemic cytokine levels. Peak peritoneal TNF-alpha levels in the anti-inflammatory group were significantly higher than in controls at 4 hours. Considerably higher serum TNF-alpha levels in the anti-inflammatory group were observed at 48 hours. Peritoneal IL-1beta and IL-6 levels in the anti-inflammatory group remained similar to those in controls, while serum levels were noticeably lower. There was no observable difference in serum cortisol or the glucose response to laparoscopic nephrectomy among the groups. CONCLUSIONS: While preserving core body temperature, humidified, warmed CO2 did not affect local or systemic trends of pro-inflammatory mediators. The administration of perioperative anti-inflammatory agents produced conflicting local and systemic cytokine response of uncertain clinical significance.

Retrograde renal cooling during radio frequency ablation to protect from renal collecting system injury.

PURPOSE: We evaluated the protective effect of continuous retrograde irrigation of ice-cold saline on the renal collecting system during central parenchymal temperature based radio frequency ablation (RFA). MATERIALS AND METHODS: In 10 domestic pigs bilateral, centrally located renal parenchymal RFA lesions (intended 2 cm in diameter) were created that intentionally involved the collecting system. RFA probe placement was guided by fluoroscopy with retrograde collecting system opacification and simultaneous direct laparoscopic visualization. In 1 renal unit RFA was performed while infusing ice-cold saline through a previously placed ureteral access sheath and pigtail stent. RFA without renal cooling was performed in the contralateral renal unit. Kidneys were harvested at 7 days. The renal collecting system was inspected for injury by performing retrograde pyelograms and by histological examination of the collecting system adjacent to the ablation zone. The size of RFA lesions was measured. RESULTS: In retrograde cooling procedures the temperature of saline irrigant was -1.0C and the mean temperature of the effluent was 13C. One of 10 cooled renal units demonstrated contrast material extravasation from the collecting system involved by the ablation zone compared with 7 of 10 noncooled renal units (p = 0.025). Lesion size was comparable between cooled kidneys and controls (2.67 and 2.72 cm, respectively, p = 0.629). CONCLUSIONS: Retrograde renal cooling helps protect the renal collecting system from injury during RFA without a decrease in expected lesion size. Clinically retrograde renal cooling may decrease the risk of collecting system injury and subsequent complications during RFA.

Contrast-enhanced ultrasound evaluation of radiofrequency ablation of the kidney: reliable imaging of the thermolesion.

BACKGROUND AND PURPOSE: Radiofrequency ablation (RFA) is limited by the inability to monitor progression of the thermal lesion. Contrast-enhanced ultrasonography (CEUS) imaging has considerable potential as a monitoring modality for RFA. We report our experience using CEUS to evaluate the lesion produced by RFA in a porcine model. MATERIALS AND METHODS: Five pigs underwent laparoscopic RFA twice, spaced by a 1-week interval. Post- RFA ultrasound imaging was performed transcutaneously immediately after ablation. The kidneys were assessed for a contrast void corresponding to the ablated tissue. The kidneys were then harvested and the gross RFA lesions measured to compare lesion size with that measured using CEUS. RESULTS: A clear lesion was identified at the site of each RFA application. As measured by CEUS, the acute lesions averaged 1.8 +/- 0.4, 1.7 +/- 0.4, and 1.8 +/- 0.3 cm in length, height, and width, respectively, compared with 2.0 +/- 0.5, 1.8 +/- 0.4, and 1.9 +/- 0.3 cm, respectively, by measurement in the gross specimen (P = 0.33, 0.13, and 0.44, respectively). At 1 week, the CEUS-measured dimensions of the lesions were 2.7 +/- 0.5, 2.6 +/- 0.6, and 2.6 +/- 0.6 cm, and the gross measurements of the lesion were 2.7 +/- 0.4, 2.7 +/- 0.9, and 2.6 +/- 0.4 cm (P = 0.75, 0.92, and 0.40, respectively). CONCLUSIONS: Contrast-enhanced ultrasonography appears to be an accurate modality for immediate monitoring of RFA defects. Further study is necessary to assess the clinical utility of CEUS for monitoring RFA of small renal lesions.

Acute histologic effects of temperature-based radiofrequency ablation on renal tumor pathologic interpretation.

OBJECTIVES: To describe the histopathologic changes and evaluate the interpretability of human renal tumor specimens obtained after temperature-based radiofrequency ablation (RFA). METHODS: RFA of 119 solid kidney tumors was performed percutaneously under computed tomography guidance, laparoscopically or during open surgery, using a temperature-based system. Of the 119 tumors, 70 were biopsied (two or more samples) after RFA, 39 immediately before ablation, and 10 were not biopsied. All specimens were pathologically classified, and for those specimens obtained after RFA, analysis of the acute histologic changes secondary to RFA was performed by a single pathologist using standard hematoxylin-eosin staining. RESULTS: Ablated tumor specimens maintained their tissue architecture and had predictable changes (cytoplasmic eosinophilia, nuclear elongation, cytoplasmic dissolution) easily recognizable by our pathologists. The diagnostic rate of renal cell carcinoma after RFA (72%) was comparable to the diagnostic rate reported for tumors less than 4 cm in other non-RFA biopsy series. Only 2.6% of specimens obtained before and 5.7% obtained after RFA were nondiagnostic secondary to the paucity of tissue obtained. In 8.3% of all tumors (regardless of RFA treatment), the distinction between oncocytoma and low-grade oncocytic renal cell carcinoma could not be made because of insufficient tissue. CONCLUSIONS: Acutely, RFA of renal tumors causes predictable histologic changes and preserves the tissue architecture. Obtaining two or more incisional biopsies after RFA provided sufficient tissue for reliable pathologic diagnosis.

Hand assisted laparoscopic cystectomy with minilaparotomy ileal conduit: series report and comparison with open cystectomy.

PURPOSE: To achieve less patient morbidity our initial experience with hand assisted laparoscopic (HAL) cystectomy was compared with our results of open cystectomy with similar urinary diversion. MATERIALS AND METHODS: During 18 months 36 cystectomies were performed, including 20 with open continent diversion. A prospective, nonrandomized comparison of the remaining 16 consecutive cystectomies with ileal conduit diversion (hand assisted laparoscopic cystectomy and open cystectomy in 8 cases each) was performed. Of the 16 cystectomies 13 were performed for muscle invasive bladder cancer. Standard parameters were compared concerning patient operative and postoperative courses using statistical analysis with the 2-tailed t test. A novel surgical technique for completing these HAL procedures is described and compared to standard open cystectomy and ileal conduit diversion. RESULTS: A total of 16 patients successfully underwent open (8) and HAL (8) cystectomy with an ileal conduit. Mean estimated blood loss in the HAL and open groups was 637 and 957 cc, respectively (p = 0.23). The mean postoperative parenteral analgesia administered was 31 mg in the HAL group vs 149 mg in the open group (p = 0.01). The HAL and open groups had a mean length of stay of 6.4 vs 9.8 days (p = 0.06). Mean operative time did not differ significantly between the HAL and open groups (403 and 420 minutes, respectively). Regular diet was resumed at 4.5 days in the HAL group vs 7.9 days in the open group (p = 0.05). Hospital length of stay was 6.4 vs 9 days for HAL vs open cases (p = 0.06). CONCLUSIONS: To our knowledge this represents the first reported series of patients undergoing HAL cystectomy with urinary diversion. HAL cystectomy with an ileal conduit appears to have less estimated blood loss and postoperative analgesic requirements, shorter length of stay and earlier return of bowel function than open cystectomy. Oncological efficacy was preserved in the short term.

The radiographic evolution of radio frequency ablated renal tumors.

PURPOSE: Radio frequency ablation (RFA) of renal tumors is a relatively new technology. Few groups are familiar with the posttreatment appearance of these lesions and how they differ from cryoablated renal masses. We describe the evolution of the appearance of these lesions on followup contrast enhanced (CE) computerized tomography (CT). METHODS AND MATERIALS: A total of 64 consecutive renal tumors treated with RFA from April 2000 to September 2003 for which posttreatment CE-CT was done were included in this study. CE-CT was reviewed at 6 weeks, 3 months, 6 months and every 6 months thereafter to determine the characteristic features and evolution of these lesions. RESULTS: Renal tumors were treated with CT guided percutaneous (34), laparoscopic (28) or open (2) RFA. At a median followup of 13.7 months (range 6 weeks to 29 months) 62 RFA lesions demonstrated an absence of contrast enhancement on CE-CT. Treated endophytic tumors developed a low density, nonenhancing, wedge-shaped defect with fat infiltration seen between the ablated tissue and normal parenchyma. Treated exophytic tumors retained a configuration similar to that of the original with a lack of contrast enhancement and minimal shrinkage. Percutaneous treated lesions developed a peritumor scar or halo that demarcated ablated and nonablated tissue (perirenal fat). Persistent tumor was marked by contrast enhancement within the ablation borders of the original mass in 1 case, whereas tumor recurred after initial successful ablation with an enhancing nodule in 1. CONCLUSIONS: The radiographic features and evolution of radio frequency ablated renal tumors are unique. Successfully treated tumors demonstrated no contrast enhancement, minimal shrinkage and occasional retraction from normal parenchyma by fat infiltration.

Development of a renal tumor mimic model for learning minimally invasive nephron sparing surgical techniques.

PURPOSE: New laparoscopic partial nephrectomy and tumor ablation techniques are continuously being developed and evaluated in large animal models. However, to our knowledge no reliable renal tumor model exists to evaluate procedure efficacy. We developed and assessed the reliability of a tumor mimic model to serve as a training tool for minimally invasive kidney surgery. MATERIALS AND METHODS: An agarose based model was created using a mixture of 3% agarose, 3% cellulose, 7% glycerol and 0.05% methylene blue. It is liquid when heated, but solidifies after cooling to physiological temperatures. The agar was injected (0.7 cc) into porcine renal parenchyma to make endophytic or completely intraparenchymal lesions. Three-dimensional ultrasound images of the lesions were obtained during initial development to ensure spherical lesions. A group of 20 lesions was initially placed in an ex vivo setting to assess size consistency and define baseline impedance characteristics. An additional 20 tumor mimics each were established in a laparoscopic model in a laparoscopic box trainer and an in vivo laparoscopic model. They were ablated with a temperature based radio frequency generator to assess impedance characteristics but the efficacy of ablation was not assessed. The in vivo model consisted of placing the agar lesion percutaneously under direct laparoscopic vision. RESULTS: The agarose mixture was easily injected and readily visible on ultrasound as hyperechoic distinct lesions. Lesions had a mean size of 10.8 +/- SD 1.3 mm on ultrasound and 10.9 +/- 1.2 mm grossly. The impedance of normal renal parenchyma and unablated lesions was similar. Mean lesion size in the ex vivo model after radio frequency ablation was 9.8 +/- 2.0 mm on ultrasound, which was similar to the gross mean lesion size of 9.7 +/- 1.0 mm. Similar results were obtained for the in vivo model with a mean size of 10.1 +/- 2.1 and 10.4 +/- 1.5 mm, respectively. The lesions were easily identified grossly as blue solid lesions that replaced renal parenchyma. CONCLUSIONS: The described renal tumor mimic model reproducibly creates ex vivo and in vivo porcine kidney lesions. Lesion size and impedance do not change with the application of radio frequency energy. This model should be a valuable adjunct in the development, assessment and teaching of novel, nephron sparing, minimally invasive surgical techniques.

Applications of laparoscopic surgery in urology: impact on patient care.

From its first use as a diagnostic tool, urologic laparoscopy has developed into a complex therapy for both benign and malignant disease. Most procedures are still performed at large centers with experienced laparoscopists but nonacademic urologists are starting to gain the necessary training and skills. With the clear advantage that laparoscopy shows over open procedures in terms of decreased perioperative morbidity and quicker recovery times, patients are increasingly asking for this approach. The urologic community must meet this challenge and train future urologists to meet the expected demand.

The effects of radio frequency ablation on renal function and blood pressure.

PURPOSE: Radio frequency ablation (RFA) is evolving as a nephron sparing treatment alternative for select patents with small renal tumors. The impact of ablated tissue on the remaining kidney parenchyma is unknown. To assess this impact we evaluated pretreatment and posttreatment serum creatinine (sCr), and blood pressure of patients treated with RFA with at least 6 months of followup. MATERIALS AND METHODS: From our series of 69 tumors treated with RFA 25 patients with a total of 26 tumors and a minimum 6-month followup were identified. RFA was delivered percutaneously or laparoscopically depending on tumor location and patient preference. Blood pressure measurements and sCr levels were obtained at preoperative and postoperative office visits. Values for preoperative and postoperative systolic blood pressure, diastolic pressure and sCr were each compared. Estimated creatinine clearance was calculated for each patient before and after treatment, and compared. RESULTS: No patient experienced new onset hypertension or worsening of existing hypertension. Likewise no changes in mean sCr and estimated creatinine clearance were observed. CONCLUSIONS: Treatment with RFA does not appear to have an effect on renal function or blood pressure. RFA appears to be a medically safe therapy for patients with small renal tumors.