Monitored Extended Secondary Arterial Ischemia in a Free Muscle Transfer

Abstract

In reconstructive microsurgery, flap failure can be catastrophic to the patient. Different monitoring methods have been implemented in an attempt to recognize secondary ischemia during its early stages. However, the exact onset of secondary ischemia can be difficult to determine because there are no well-documented and reliable monitoring techniques that offer true continuous monitoring in a clinical setting. Because of the uncertain time in terms of the onset of secondary ischemia, the exact length of ischemia before revascularization, the secondary ischemia time, cannot be obtained. This is probably part of the reason why not much has been published regarding the effect of secondary ischemia time in reference to flap survival. We present a case of a free gracilis muscle flap that was salvaged despite more than 11 hours of arterial ischemia. The flap was monitored using microdialysis and at no time was the ischemia clearly demonstrated by clinical inspection. We conclude that clinical monitoring in some cases can be an unreliable method for monitoring free muscle transfers suffering from arterial ischemia and that further studies are needed for more specific guidelines regarding the critical secondary ischemia time in muscle flaps.

Current Evidence for Postoperative Monitoring of Microvascular Free Flaps

“…91,92 Similar to the implantable Doppler probes, it is potentially useful in buried flaps and cutaneous flaps that are difficult to examine. 93,94 Edsander-Nord et al 84 have illustrated the sensitivity of this technique by showing that microdialysis can detect a difference in metabolism between free and pedicled transverse rectus abdominis myocutaneous flaps, and between zones I and II of the same group of flaps. 85 Sorensen 95 successfully used microdialysis in buried free jejunal transfers to identify flap compromise early and salvage 2 such flaps.…”

Does an Early and Aggressive Combined Wrapping and Dangling Procedure Affect the Clinical Outcome of Lower Extremity Free Flaps?—A Randomized Controlled Prospective Study Using Microdialysis Monitoring

“…Critical concentrations < 2 mmol/L indicating ischemia as described in the literature were only seen in single measurements with no correlation to clinical signs of flap ischemia. 4,20,23,24,30,31 The ANCOVA model used to evaluate the primary end point results in an estimate for the change from baseline of 0.976, with corresponding 95% confidence interval (0.79; 1.76). Assuming a noninferiority boundary of 15% as specified in the protocol, this leads to a noninferiority range of (0.85; 1.76).…”

“…Critical concentrations of ischemia parameters have been described to be evident 1 to 5 hours before visible clinical signs therefore leading to early recognition and intervention. 4,20,30,31 In our study, we used MD in addition to clinical observation in both groups. Our results of MD measurements showed no disadvantage or metabolic signs of ischemia with an early onset of FT.…”

Faster Detection of Ischemia in Free Muscle Transfer When Using Microdialysis

“…ischemia, reperfusion within the first 4 hours is recommended if possible. 4,5 Recent reports have shown that an early reintervention of an FTT suffering from ischemia is essential to salvage the transfer. 6 Likewise, it has been shown that the salvage rate and the final success rate are higher in monitored transfers compared with buried transfers, which could not be monitored.…”