Is dangling of the lower leg after a free flap reconstruction necessary? Study protocol for a large multicenter randomized controlled study

Abstract

Background Within the field of plastic surgery, free tissue transfer is common practice for knee and lower leg defects. Usually, after such free flap reconstruction, patients undergo a dangling protocol in the postoperative phase. A dangling protocol is designed to gradually subject the free flap to increased venous pressure resulting from gravitational forces. Worldwide there are multiple variations of dangling protocols. However, there is no evidence available in the literature that supports the use of a dangling protocol. Methods This is a multicenter randomized controlled trial that includes patients with a free flap lower leg reconstruction. The primary outcome is to assess whether a no-dangling protocol is not inferior to a dangling protocol, in terms of proportion of partial flap loss, 6 months after surgery. Secondary objectives are to identify differences in major and minor complications, length of stay, and costs, and to objectify blood gaseous changes during dangling. Furthermore, at 2 years we will assess difference in physical function, infection rates, and osseous union rates. Discussion The primary outcome of this study will give a more decisive answer to the question of whether a dangling protocol is necessary after a free flap reconstruction of the lower leg. The secondary outcomes of this study will provide a better insight into the physical functions, infection rates, and union rates in these patients. Trial registration Central Committee on Research Involving Human Subjects (CCMO), NL63146.041.17. Registered on 11 July 2018. Netherlands Trial Register, NTR7545. Registered on 10 October 2018.

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

“…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] . Systematic reviews have shown that early dangling appears to be safe and may lead to reduced length of stay [1,7] .…”

“…Systematic reviews have shown that early dangling appears to be safe and may lead to reduced length of stay [1,7] . However, a wide variability in practice has been demonstrated in multiple countries, and there is no consensus over the best time to introduce dangling, with even less evidence for weight bearing [1,20,21] . A systematic review of dangling regimes published in 2017 stated that, traditionally, dangling begins on around day 5 but concludes that dangling may be safe from as early as day 3 [22] .…”

Tissue Oximetry Changes during Postoperative Dangling in Lower Extremity Free Flap Reconstruction: A Pilot Study

“…Life 2023, 13, 1158. https://doi.org/10.3390/life13051158 https://www.mdpi.com/journal/life Moreover, flap perfusion and viability are often determined by clinical observation, as well as results obtained by Doppler ultrasonography [6,8]. This is still the gold standard for assessing flap viability [5,9,10].…”