Early initiation of dangle protocol in lower-extremity free-flap microsurgery

Authors: Su S, Menon A, Taillon C, Saad O, Merceron T, Ghareeb P

Affiliation: Emory University/Grady Memorial Hospital

Journal: Journal of Reconstructive Microsurgery, January 2025

PMID: 39750583

Key takeaways

• Initiating dangle by POD ≤5 was safe and associated with shortened postoperative length of stay (LOS 12.3 vs 18.8 days, p=0.0018); total hospital LOS also shorter (24.0 vs 35.3 days, p=0.0067).

• On multivariable analysis, each 1-day delay in starting dangle was linked to a 13% lower discharge probability (Cox model) and higher odds of flap loss (OR 1.31 per day; p=0.019).

Background

Lower-extremity flaps face high venous pressures in dependency; “dangling” conditions the flap but timing varies widely (POD <2 to >14).

Objective

Evaluate safety and LOS impact of earlier (≤POD5) versus later (>POD5) initiation of a dangle protocol after lower-extremity free-flap reconstruction.

Methods

• Design/setting: Retrospective cohort, single institution (2012–2022).

• Cohort: 83 patients included (Early dangle n=22; Late n=61; 99 screened). A priori power reported (0.95).

• Protocol: Start at 5 minutes dangling three times daily; escalate by 5 minutes per dangle for each subsequent day if flap exam stable.

• Outcomes: Postop LOS (primary), hospital LOS, wound complications, flap failure, amputation, time to ambulation.

Results

• Safety: No significant differences in wound complications, flap failure (9.1% early vs 9.8% late), or amputation between groups; time to ambulation similar.

• Length of stay: Postop LOS 12.3 vs 18.8 days (p=0.0018); hospital LOS 24.0 vs 35.3 days (p=0.0067) favoring early dangle.

• Multivariable findings:

  • Each day’s delay in dangle → lower discharge probability (~13% per day; model p=0.00016).

  • Flap loss: later dangle associated with higher odds (OR 1.31 per day delay, p=0.019). Smoking trended but NS.

• Operative details: Two-vein anastomoses more common in the late group; flap types mixed (ALT predominant).

Conclusion

Early dangle initiation (≤POD5) is safe and reduces LOS. Delaying dangle correlates with higher flap-loss odds and slower discharge. Adopt an earlier, monitored dangle protocol in standardized postoperative care.

Strengths & limitations

• Strengths: Explicit power analysis; multivariable modeling; effect estimates for discharge and flap loss.

• Limitations: Retrospective single-center study with significant concern for selection bias by surgeon preference determining early vs. late dangle, single vs. dual venous anastomosis, and heterogeneity in flap donor selection; small early cohort; imbalance in number of venous anastomoses between the early and late dangle groups; discharge influenced potentially by unmeasured variables, such as nonclinical factors.