Dangle Protocols in Lower Extremity Reconstruction

J Surg Res. 2021 Oct;266:77-87. doi: 10.1016/j.jss.2021.03.028. Epub 2021 May 11.


Introduction: Dangling protocols are known to vary by surgeon and center, and their specific regimen is often largely based on single surgeon or institutional experience. A systematic review was conducted to derive evidence-based recommendations for dangling protocols according to patient-specific and flap-specific considerations.

Methods: A systematic review was performed using PubMed, Embase-OVID and Cochrane-CENTRAL. Study design, patient and flap characteristics, protocol details, dangling-related complications, and flap success rate were recorded. Studies were graded using the Oxford Center for Evidence-Based Medicine Levels of Evidence Scale. Data heterogeneity precluded quantitative analysis.

Results: Eleven articles were included (level of evidence (range):IIb-IV; N (range):8-150; age (range):6-89). Dangling initiation, time, and frequency varied considerably. Flap success rate ranged from 94 to 100%. Active smoking, diabetes, and hypertension are associated with characteristic physiologic changes that require vigilance and potential protocol modification. Early dangling appears to be safe across a variety of free flap locations, sizes, and indications. Axial fasciocutaneous flaps may tolerate more aggressive protocols than muscular flaps. While flaps with single venous anastomosis tolerate dangling, double venous or flow-through anastomoses may provide additional benefit. Major limitations included small sample sizes, uncontrolled study designs, and heterogeneous patient selection, dangling practices, monitoring methods, and outcome measures.

Conclusions: Significant heterogeneity persists in postoperative dangling protocols after lower extremity microvascular reconstruction. Patient comorbidities and flap characteristics appear to affect tolerance to dangling. We propose two different standardized pathways based on risk factors. Clinical vigilance should be exercised in tailoring lower extremity protocols to patients' individual characteristics and postoperative course.

Keywords: dangle protocol; lower extremity free flap; lower extremity reconstruction.

Publication types

  • Systematic Review

MeSH terms

  • Clinical Protocols
  • Free Tissue Flaps / blood supply
  • Free Tissue Flaps / surgery*
  • Humans
  • Lower Extremity / surgery*
  • Microsurgery / methods*
  • Outcome Assessment, Health Care
  • Reconstructive Surgical Procedures / methods*
  • Vascular Surgical Procedures / methods*