Pig muscle flap vascular resistance

• Main Author: Chao, Hubert YM
• Language: English
• Published: 2009
• Online Access: http://hdl.handle.net/2429/7674

Free muscle transfer is a surgical procedure used for treating wounds that may result from trauma, cancer excision, radiation necrosis, or defects due to congenital anomaly. It is often a salvage procedure and failure results in significant morbidity. Choke vessels may have a role in such failures. These vessels interconnect vascular territories which each have associated vascular pedicles. Choke vessels are believed to have high vascular resistance and are implicated in thrombosis leading to flap failure. The vascular resistance of choke vessels has not previously been studied. The objective of this study was to determine the relationship between muscle flap vascular resistance and the presence or absence of choke vessels in the intraoperative period following muscle flap elevation in quantifiable terms. The alternative hypothesis is that the surgical resection of the zone of choke vessels from a muscle flap results in a statistically significant decrease in muscle flap vascular resistance per unit weight. Under isoflurane anaesthesia, 8 pig rectus abdominis flaps were elevated on the superior epigastric pedicle. The pedicles were sympathectomized. The flaps were serially resected towards the pedicle, resecting the zone of choke vessels in the process, with vascular resistance and flap weight determined concurrently. As the choke vessels were resected, no decrease in vascular resistance per unit weight was observed. Control flaps were included in the study, as well gracilis flaps were studied for comparison. The power of this study was 0.98. The role of choke vessels in failure of muscle flaps remains unclear. Vascular resistance per unit weight was seen to increase as muscle flaps were serially resected. A possible mechanism for this is the myogenic response. The myogenic response although well described has not previously been associated with muscle flaps.