Date of Award
School of Engineering
Partial nephrectomy has become the preferred method of treatment in certain renal diseases, including small, peripheral tumors. However, re-establishment of hemostasis in the remaining tissue remains a challenging procedure. To better understand the forces involved in re-approximation of the renal remnant, this study measures the suture tensions reached in sliding clip renorrhaphy, as well as the ability of the tissue to support those tensions, and reviews how long suture material might be expected to survive those forces.
Three separate groups of experiments were conducted on fresh, porcine kidney tissue. Treatment groups were compared using commercially available software to compute appropriate descriptive statistics and generate regression lines.
Suture tension was measured at 2.8 ± 0.7 Newtons (N) (mean ± standard deviation) in ischemic organs, 3.2 ± 0.7 N in kidneys at normal perfusion and 3.4 ± 0.7 N at perfusion levels over 200 mm Hg (107 inches H2O).
Other experiments measured the tension required to cause tissue in both complete sutures (terminated on both ends with surgical clips) and half sutures (placed in a hemisphere of tissue and terminated with a clip only on the trailing end) to be torn from the organ. Positive relationships were shown between the amount of enclosed tissue (margin size) and the tension at failure for both complete and partial sutures. Margins below 1 cm in size failed at levels which could affect their usefulness in closing the parenchyma. Also, a positive correlation between failure tension and angle of applied force relative to the capsule surface was observed for angles in the range of 0º to 90º. In a related experiment, different diameter sutures were tested on standard sized specimens. Differences in the force required to cause the suture to cut through the samples were not shown in the small sample.
The tensile strengths of suture material at eight different durations of exposure to select environmental conditions were tabulated so that materials appropriate for renorrhaphy can be identified. Tensile strength before and after exposure, size, and environmental conditions were listed. Data indicates that appropriate materials can be selected from available suture.
Endres, Donald M. II, "Investigation of the Closing Forces Involved in Re-Approximation of the Renal Remnant Following Partial Nephrectomy" (2013). Masters Theses. 52.