A Scanning Electron Microscopic Study about Crush Injured Vasospasm after Freezing Therapy

ABSTRACT

The histologically confirmed endothelial damage (HCED) may lead to vasospasm, which increases the failure rate of microvascular anastomosis. Recently, vascular freezing has been reported to be the most effective and lasting method of alleviating or preventing vessel constriction in virgin microvessels. We question whether the application of freezing designed to relieve vasospasm is possible in microvessels accompanying with underlying acute endothelial damages without any harmful effects. We produced an experimental model with histologically confirmed endothelial damage and vasospasm in Sprague-Dawley rat. In crush injury group(group I, n = 15), the determined crushing load (0.07 J) was applied to femoral artery. In crush injury-freezing group(group II, n = 15), crushed arteries was frozen with ethyl chloride at 30 minutes after applying the crush injury. Gross and scanning electron microscopic appearances were inspected in both experimental groups on the 2nd, 14th and 30th day after the operation. In group I, vasospasm around the crushed segments were continued but in group II, the vasospasm disappeared immediately after vascular freezing, maintained its expansion even at postoperative 2, 14 and 30 days. On scanning electron microscopic examination, endothelium in group II showed slightly slower regeneration velocity but near complete regeneration was achieved at postoperative day 30. Regenerated endothelial cell in group II was more atypically shaped but arranged longitudinally at postoperative day 30. In conclusion, freezing with ethyl chloride could be a useful tool to reliably revert vasospasm without inducing thrombus even in acute endothelial damaged vessels after crush injury.