Temporary targeted renal blood flow interruption using a reverse thermosensitive polymer to facilitate bloodless partial nephrectomy: a swine survival study

An optimized procedure for stained bloodless anatomic hepatectomy in canines

BACKGROUND

Poloxamer 407 (P407) is a thermosensitive polymer that can gelatinize at body temperature and dissolve below critical temperature. The aim of this study was to evaluate an optimized procedure for hepatectomy, in which the target liver section was stained with methylene blue, and the blood inflow was occluded with P407.

METHODS

Twelve dogs were randomized into two equal groups. The conventional group (CG) underwent unstained liver resection with the hemi-Pringle maneuver for blood control. After angiography, the optimized group (OG) was cannulated to the target lobar hepatic artery via the femoral artery and to the target segmental portal vein via a branch of the splenic vein. The artery was then occluded with P407, whereas the vein was administered methylene blue and P407 sequentially before excision along the stained border. Blood specimens and necropsy were acquired periodically.

RESULTS

The stained resection margins were clearly visualized and were accompanied by negligible blood loss. The occlusion duration was significantly reduced from 24.5 ± 2.3 min in the conventional group to 18.5 ± 4.9 min in the OG (P < 0.05). The aspartate aminotransferase and alanine aminotransferase levels were less elevated in the OG postoperatively. No significant evidence of pathology was detected in either group.

CONCLUSIONS

This optimized procedure represents an easy, time-saving and effective approach for stained anatomic hepatectomy with temporary intravascular blood occlusion.

Feasibility of quantitative diffuse reflectance spectroscopy for targeted measurement of renal ischemia during laparoscopic partial nephrectomy

Reduction of warm ischemia time during partial nephrectomy (PN) is critical to minimizing ischemic damage and improving postoperative kidney function, while maintaining tumor resection efficacy. Recently, methods for localizing the effects of warm ischemia to the region of the tumor via selective clamping of higher-order segmental artery branches have been shown to have superior outcomes compared with clamping the main renal artery. However, artery identification can prolong operative time and increase the blood loss and reduce the positive effects of selective ischemia. Quantitative diffuse reflectance spectroscopy (DRS) can provide a convenient, real-time means to aid in artery identification during laparoscopic PN. The feasibility of quantitative DRS for real-time longitudinal measurement of tissue perfusion and vascular oxygenation in laparoscopic nephrectomy was investigated in vivo in six Yorkshire swine kidneys (n=three animals ). DRS allowed for rapid identification of ischemic areas after selective vessel occlusion. In addition, the rates of ischemia induction and recovery were compared for main renal artery versus tertiary segmental artery occlusion, and it was found that the tertiary segmental artery occlusion trends toward faster recovery after ischemia, which suggests a potential benefit of selective ischemia. Quantitative DRS could provide a convenient and fast tool for artery identification and evaluation of the depth, spatial extent, and duration of selective tissue ischemia in laparoscopic PN.