Temporal Trends in Selecting Patients for Partial Nephrectomy for Small Renal Cell Carcinomas in Alberta, Canada.

BACKGROUND: When technically feasible, partial nephrectomy (pN) is preferred over radical nephrectomy (rN) due to similar oncological control with preservation of renal function. Here, we evaluate the incorporation of pN into practice for small renal masses and examine the associated outcomes. METHODS: We included patients who had undergone either a partial or radical nephrectomy in Alberta, Canada for renal cell carcinomas with pathology tumor stage T1a between 2002 and 2014 (N=1449). Patients were excluded if they had multiple tumors or if they were on dialysis prior to nephrectomy. RESULTS: pN use increased over the duration of the study period. Patients treated after the introduction of guidelines (2007) recommending the use of pN were significantly more likely to receive a pN (OR: 2.709, 95% CI: 1.944-3.775; p<0.001) after adjusting for baseline estimated glomerular filtration rate (GFR), age, and sex. Patients who received rN were at significantly increased risk of death (HR: 1.528, 95% CI: 1.029-2.270; p=0.036) after controlling for baseline GFR, age, and sex. Baseline GFR significantly affected odds of receiving pN (p<0.050) in the entire cohort, but subgroup analysis of more recently diagnosed patients (2011-2014) showed that only patients with kidney failure (GFR <15) were less likely to have received pN. DISCUSSION: The utilization of pN for patients with pT1a renal cell carcinoma has increased significantly over time and has been accelerated by the introduction of guideline recommendations. Patients treated with pN over the study period had superior overall survival.

A Force-Sensing Insole to Quantify Impact Loading to the Foot.

Lower leg injuries commonly occur in frontal automobile collisions, and are associated with high disability rates. Accurate methods to predict these injuries must be developed to facilitate the testing and improvement of vehicle safety systems. Anthropomorphic test devices (ATDs) are often used to assess injury risk by mimicking the behavior of the human body in a crash while recording data from sensors at discrete locations, which are then compared to established safety limits developed by cadaveric testing. Due to the difference in compliance of cadaveric and ATD legs, the force dissipating characteristics of footwear, and the lack of direct measurement of injury risk to the foot and ankle, a novel instrumented insole was developed that could be applied equally to all specimens both during injury limit generation and during safety evaluation tests. An array of piezoresistive sensors were calibrated over a range of speeds using a pneumatic impacting apparatus, and then applied to the insole of a boot. The boot was subsequently tested and compared to loads measured using ankle and toe load cells in an ATD, and found to have an average error of 10%. The sensors also provided useful information regarding the force distribution across the sole of the foot during an impact, which may be used to develop regional injury criteria. This work has furthered the understanding of lower leg injury prediction and developed a tool that may be useful in developing accurate injury criteria in the future for the foot and lower leg.

Effect of posture on forces and moments measured in a Hybrid III ATD lower leg.

OBJECTIVE: Anthropomorphic test devices (ATDs) are used to assess real injury risk to occupants of vehicles during injurious events. In the lower leg, values from load cells are compared to injury criteria developed in cadaveric studies. These criteria are typically developed with the leg in a neutral posture, whereas the ATD may assume a wide range of postures during safety evaluation tests. The degree to which the initial posture of an ATD has an effect on the measured forces and moments in the lower leg is unknown. METHODS: A Hybrid III ATD lower leg was impacted in a range of postures under conditions representing a crash test, and peak axial force and adjusted tibia index injury measures were evaluated. Ankle posture was varied in 5° increments using a custom-made footplate, and dorsi/plantarflexion (20° DF to 20° PF) and in/eversion (20° IV to 5° EV) were evaluated. Tibia angle was also varied (representing knee flexion/extension) by ±10° from neutral. RESULTS: Peak axial force was not affected by ankle flexion or tibia angulation. Adjusted tibia index was lowest for plantarflexion, as well as for tibia angles representative of knee extension. Both peak axial force and adjusted tibia index were lowest for postures of great inversion and were highest in neutral or near-neutral postures. CONCLUSIONS: The range of postures tested herein spanned published injury criteria and thus would have made the difference between pass and fail in a safety evaluation. In/eversion had the largest influence on injury metrics, likely due to the change in axial stiffness and altered impact durations in these postures. Results suggest increased injury risk at neutral or near-neutral postures, whereas previous cadaveric studies have suggested that in/eversion does not influence injury risk. It is unclear whether the ATD appropriately represents the natural lower leg for impacts in out-of-position testing. Great care must be taken when initially positioning ATDs for safety evaluations, because small perturbations in posture were shown herein to have large effects on the measured injury risk using this tool.