Tekisha U. Lindler

Prospective Comparison of Four Laparoscopic Vessel Ligation Devices

PURPOSE The merits of laparoscopic sealing devices have been poorly characterized. The purpose of this study was to compare two bipolar sealing devices [LigaSure V (LS) and Gyrus PK (GP)], an ultrasonic device [Harmonic Scalpel ACE (HS)] and a novel device using nanotechnology [EnSeal PTC (ES)]. MATERIALS AND METHODS The ability of all four 5 mm devices to seal 5 mm bovine arteries was tested under controlled temperature and humidity in accordance with manufacturer specifications. Study endpoints included lateral thermal spread, time to seal, burst pressure, smoke production and subjective (blinded review of video clips) and objective (measured using an aerosol monitor) effect upon visibility. RESULTS The HS demonstrated the least thermal spread. The LS (10.0 secs) and GP (11.1 secs) had the fastest sealing times (p<0.001 for both) when compared to ES (19.2 sec) and HS (14.3 sec). Mean burst pressure values were: LS 385 mm Hg, GP 290 mm Hg, ES 255 mm Hg and HS 204 mm Hg. The HS had the best subjective visibility score and the lowest objective smoke production (2.88 ppm) compared to the GP (74.1 ppm), ES (21.6 ppm) and LS (12.5 ppm), (p<0.01 for all). CONCLUSIONS The LS has the highest burst pressure and fastest sealing time and was the highest rated overall. The HS produced the lowest thermal spread and smoke but had the lowest mean burst pressure. The GP had the highest smoke production, and variable burst pressures. Despite employing nanotechnology, the ES device was the slowest and had variable burst pressures.

Effect of Reduced Radiation CT Protocols on the Detection of Renal Calculi

PURPOSE To determine the effect of reduced radiation (tube charge, measured as milliamperes per second) protocols on the sensitivity and specificity of multidetector computed tomography (CT) in the detection of renal calculi. MATERIALS AND METHODS This Health Insurance Portability and Accountability Act-compliant human cadaveric study was approved by the Department of Anatomic Pathology with strict adherence to the university policy for handling donor specimens. Three to five renal stones (range, 2.0-4.0 mm) were randomly placed in 14 human cadaveric kidneys and scanned with a 16-detector CT scanner at 100, 60, and 30 mAs while maintaining other imaging parameters as constant. Following acquisition, images were reviewed independently by two radiologists who were blinded to the location and presence of renal calculi. Interobserver agreement was measured with kappa statistics. The McNemar test was used to compare the sensitivity and specificity between different radiation settings for each reader. RESULTS Specificity for both readers ranged from 105 (0.95; 95% confidence interval [CI]: 0.90, 0.99) to 109 (0.99; 95% CI: 0.95, 1.0) of 110 without significant differences between 30 and 60 mAs to the standard 100 mAs (P = .500 to >.999). Sensitivity ranged from 42 (0.74; 95% CI: 0.60, 0.84) to 48 (0.84; 95% CI: 0.72, 0.93) of 57, also without significant differences (P = .070 to >.999). When renal calculi detection rates were analyzed by size, 3.0-4.0-mm stones were detected well at all tube charge settings, ranging from 86%-90% (n = 21 for 3.0-mm stones) to 95%-100% (n = 19 for 4.0-mm stones). However, 2.0-mm stones were poorly detected at all tube charge settings (29%-59%; 5-10 of 17). Overall interobserver agreement for stone detection was excellent, with kappa = 0.862. CONCLUSION Decreasing the tube charge from 100 to 30 mAs resulted in similar detection of renal stones while reducing patient radiation exposure by as much as 70%. Multidetector CT scanning parameters should be tailored to minimize radiation exposure to the patients while helping detect clinically significant renal stones.

Laparoscopic Donor Nephrectomy: Effect of Perirenal Fat upon Donor Operative Time

PURPOSE Previous attempts to correlate preoperative patient characteristics with operative complexity and operative time prior to laparoscopic donor nephrectomy have found few consistent relationships. The purpose of this study is to determine the effect of abdominal and perirenal fat measured with preoperative computerized tomography (CT) upon subsequent operative time and complexity during hand-assisted laparoscopic donor nephrectomy. MATERIALS AND METHODS A retrospective chart, database, and CT angiogram review was conducted on 103 consecutive patients who underwent a hand-assisted laparoscopic donor nephrectomy. Perirenal fat and abdominal wall fat were correlated with a variety of parameters including operative time. Univariate and multivariate regression analysis was performed and p values<0.05 were considered significant. RESULTS There was no correlation between operative time and body mass index (BMI), abdominal fat measurements, or spleno-renal distance. There was a significant positive correlation between operative time and anterior perirenal fat (r=0.28, p=0.005), posterior perirenal fat (r=0.20, p=0.05), and donor CPK levels (r=0.53, p<0.001). Men had greater perirenal fat, while women had greater abdominal fat. A multivariate model including anterior perirenal fat measurement accounted for 20% of the variance in operative time. CONCLUSION This is the first study to demonstrate that increased perirenal fat increases operative complexity as measured by operative time. This information may potentially be used to help predict operative complexity based upon measurable preoperative variables and help improve operating room efficiency and donor and recipient outcomes.

Donor Smoking Negatively Affects Donor and Recipient Renal Function following Living Donor Nephrectomy.

Background. While tobacco use by a renal transplant recipient has been shown to negatively affect graft and patient survival, the effect of smoking on the part of the kidney donor remains unknown. Methods. 29 smoking donors (SD) and their recipients (SD-R) as well as 71 non-smoking donors (ND) and their recipients (ND-R) were retrospectively reviewed. Preoperative demographics and perioperative variables including serum creatinine (Cr) and glomerular filtration rate (GFR) were calculated and stratified by amount of tobacco exposure in pack-years. Clinical outcomes were analyzed with a Students t-test, chi-square, and multiple linear regression analysis (α = 0.05). Results. At most recent followup, SD-Rs had a significantly smaller percent decrease in postoperative Cr than ND-Rs (−57% versus −81%; P = 0.015) and lower calculated GFRs (37.0 versus 53.0 mL/min per 1.73 m2; P < 0.001). SDs had a larger percent increase in Cr than NDs at most recent followup (57% versus 40%; P < 0.001), with active smokers having a larger increase than those who quit, although this difference was not statistically significant (68% versus 52%; P = 0.055). Conclusions. Use of tobacco by kidney donors is associated with decreased posttransplant renal function, although smoking cessation can improve outcomes. Kidneys from donors who smoke should be used with caution.

Renal Stone Detection Using Unenhanced Multidetector Row Computerized Tomography—Does Section Width Matter?

PURPOSE We determined the effect of reconstructed section width on sensitivity and specificity for detecting renal calculi using multidetector row computerized tomography. MATERIALS AND METHODS Three to 5 renal stones 2 to 4 mm in size were randomly placed into 14 human cadaveric kidneys and scanned by 16-row detector computerized tomography at 1.25 mm collimation and identical scanning parameters. After acquisition images were reconstructed with a section width of 1.25, 2.5, 3.75 and 5.0 mm, and reviewed independently by 2 blinded radiologists. Comparisons of sensitivity and specificity between different section widths were assessed with the McNemar test and Cochrans Q statistics. RESULTS Specificity was not significantly affected by section width (94.6% to 97.7%). In contrast, sensitivity increased as stone size increased and as section width decreased. Sensitivity to detect all stones was 80.7%, 80.7%, 87.7% and 92.1% for 5.0, 3.75, 2.5 and 1.25 mm section widths, respectively. Interobserver agreement for stone detection was excellent (kappa 0.858). Although the 2.0 mm stone detection rate improved with thinner section widths (79.4% vs 52.9% for 1.25 vs 5.0 mm, p = 0.004), stones greater than 2.0 mm were similarly detected at different slice selections (p = 0.056 to 0.572). CONCLUSIONS Independent of other scanning parameters reconstruction section width influences the ability to detect small renal calculi. It must be considered when creating computerized tomography protocols.