Animal models in lymph node transfer surgery: A systematic review.

BACKGROUND AND AIM

Lymph node transfer surgery (LNTS) is indicated in secondary lymphedema (LE) patients who do not respond to conservative therapy. Animal models are the spearhead of LE research and were used to pioneer most of the surgical interventions currently in practice. We conducted a systematic review of the literature to explore animal models dedicated to LNTS to compare different species, techniques, and outcomes.

METHODS

Four databases were searched: PubMed, Cumulative Index of Nursing and Allied Health Literature, Scopus, and Web of Science. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analysis as our basis of organization.

RESULTS

Avascular lymph node graft (ALNG) and vascularized lymph node transfer (VLNT) effectively treated LE and lead to better outcomes than controls. Whole ALNGs are superior to fragmented ALNGs. Larger fragments are more likely to be reintegrated into the lymphatic system than small fragments. VLNT was superior to whole and fragmented ALNG. Increasing the number of VLNT resulted in better outcomes. Adipose-derived stem cells improved outcomes of VLNT; vascular endothelial growth factor C and D and platelet-rich plasma improved outcomes for ALNG. Cryopreservation of lymph nodes (LNs) did not affect outcomes for ALNG. The critical ischemia and venous occlusion time for LN flaps were 4-5 and 4 h, respectively. The critical time for reperfusion injury was 2 h. Some of the novel models included venous LNT, and cervical adipocutaneous flap to groin.

CONCLUSION

Current evidence from animals favors VLNT over other surgical interventions. Several pharmacological therapies significantly improved outcomes of ALNG and VLNT.

RELEVANCE TO PATIENTS

LE is a chronic condition affecting millions of patients worldwide. LNTS is becoming more popular as a LE treatment. Animal models have led the LE research for decades and developing new models for LE are essential for LE research. This systematic review aims to summarize the existing animal models dedicated to LNTS. We believe that this review is critical to guide researchers in the selection of the model that is best fit for their hypothesis-driven experiments.