Canadian Postoperative Dependency Protocols Following Lower Limb Microvascular Reconstruction: A National Survey and Literature Review

Abstract

Introduction: Microsurgical free tissue transfer for lower limb reconstruction presents unique challenges in the postoperative period where dependency promotes interstitial fluid diffusion and reduced tissue perfusion. Management of flap edema, venous congestion, and ischaemic conditioning is critical for flap survival. Little evidence exists to guide postoperative protocols in the initiation and progression of lower extremity dangle, monitoring, and anticoagulation. We aim to describe current trends for postoperative dependency protocols by surveying Canadian microsurgeons. Methods: Plastic surgeons performing lower limb microvascular reconstruction at Fellow of The Royal College of Surgeons of Canada approved teaching institutions were administered a 17-question anonymous electronic survey. A literature review was conducted to identify protocols and consensus opinions in other jurisdictions. Results: All respondents (n = 16) monitored flaps clinically, with conventional Doppler used by 13 respondents. Anticoagulation was employed by 15 of 16 respondents, and 9 of 16 used 2 or more agents. The most common agents were aspirin, followed by low-molecular-weight heparin. Significant variability existed in dangling protocols. Dependency was initiated at postoperative day (POD) 3 to 10 (mean POD: 6 ± 1.64 standard deviation), with intervals ranging from 5 to 20 minutes and frequencies ranging from 1 to 6 times per day. Nearly half allowed both increasing duration and frequency of dependency. Flap success rates were above 90%, and the median length of stay was 10 to 12 days. Conclusion: While flap success rates across the country are similar, no consensus exists for postoperative dependency protocols amongst Canadian microsurgeons. Prospective randomised controlled trials are warranted to evaluate early aggressive dependency protocols to reduce length of stay and cost.

Comparison of outcomes between early and delayed weight bearing following lower limb free flaps: an 18-month single-center study

“…Free flaps applied to the lower limbs may be especially prone to venous congestion due to their dependent position, leading to increased oedema, reduced perfusion pressure, compression of the vascular pedicle, and, ultimately, loss of the flap [16][17][18] . It has also been reported that lower limb free flaps may be at increased risk of venous congestion compared to free flaps applied elsewhere in the body, even when the limb is kept elevated [19] . In light of concerns around venous congestion, the best time from which to permit weight bearing is uncertain, and many centres have introduced "dangling protocols", the aim of which is to introduce gravitational dependency gradually to allow adaptive physiological responses to take place and reduce the risk of flap loss [20] .…”

Evidence-Based Approaches to Anticoagulation in Reconstructive Microsurgery—A Systematic Literature Review

“…Seven of these studies reported comparable outcomes with regard to flap survival, complication rates and adverse effects, regardless of the used vasoactive agent. No benefit was found for any particular antithrombotic drug and no consensus was found for a certain anticoagulation regime [1,[13][14][15][16][17][18].…”

“…Likewise, seven systematic reviews reported similar outcomes with regard to flap survival, complication rates and adverse effects. No advantage was found for any particular anticoagulation regime or specific drug [1,[13][14][15][16][17][18]. Two studies found higher odds for complications either with the combination of heparin and aspirin or intravenous heparin in terms of postoperative hematoma.…”