{'fraction_non_alphanumeric': 0.022908366533864542, 'fraction_numerical': 0.006474103585657371, 'mean_word_length': 5.439102564102564, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 1, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Effect of Hydrostatic Dilation on Flap Viability of the Transverse Rectus Abdominis Musculocutaneous Flap Model in Rats

Background: The technique of intraoperative vessel hydrostatic dilation is sometimes used to facilitate microvascular anastomosis and prevent vasospasm. Currently, delay procedures remain a reliable method of maximizing flap survival. The authors aimed to increase rat transverse rectus abdominis musculocutaneous (TRAM) flap viability by imitating the physical effect of a surgical delay procedure with hydrostatic dilation. Methods: Forty-five male Sprague-Dawley rats were randomly assigned to one of three TRAM flap groups (15 rats in each group): the control group, the delay group, and the hydrostatic dilation group. The surgical delay procedure was performed by division of right-sided cranial epigastric vessels and contralateral superficial inferior epigastric vessels. While elevating the flap, hydrostatic dilation was performed to the cranial epigastric artery and vein with a mean pressure of 250 mm Hg. The groups were compared by means of microangiography and survival ratio of TRAM flaps and mean artery lumen area, mean vein lumen area, and mean artery wall area of the flap pedicle 48 hours after elevation. Results: There was a significant difference between the control and hydrostatic dilation groups in favor of surface area viability and angiographic assessment (p < 0.01). Surgical delay has traditionally been accepted as the most reliable method of enhancing flap viability. No significant difference was revealed between the surgical delay and hydrostatic dilation groups (p > 0.05). In the hydrostatic dilation group, compared with the control group, an increase in vein diameter, a thinning of the artery wall, and an increase in lumen diameter were observed. Conclusions: The physical effect of blood flow is achieved acutely with hydrostatic dilation. This simple, dependable, one-stage hydrostatic dilation procedure can be used in clinical applications.