Effects of Neoadjuvant Radiation and Recipient Vessel Characteristics on Microvascular Complication Rates in Reconstruction of Lower Extremity Soft Tissue Sarcoma Defects.

Background:  The treatment approach for soft tissue sarcomas (STS) of the lower extremity has shifted toward the use of neoadjuvant radiation combined with limb-sparing surgery (LSS). The resulting defects often require reconstruction with free tissue transfer for adequate outcomes. Data have demonstrated a potentially increased risk of microvascular complications for free flaps performed using irradiated recipient vessels. Similarly, certain anatomic areas of the lower extremity have a high proportion of unnamed perforators that are available as recipient vessels, increasing the technical difficulty. We aimed to determine if the characteristics of recipient vessels that were used for the reconstruction of STS defects influenced rates of microvascular complications in our patients.

Methods:  A retrospective chart review of all patients who underwent reconstruction of lower extremity STS defects with free tissue transfer from 2009 to 2020 was conducted. Data regarding recipient vessel type (axial vessel vs. unnamed perforator), radiation status of the recipient vessels (irradiated vs. non-irradiated), and microvascular complications were compared across groups.

Results:  A total of 204 free flaps were included. The overall microvascular complication rate was 13.7% (28 cases). Most microvascular complications were detected postoperatively (82.1%) rather than intraoperatively, with the majority involving venous congestion/thrombosis (20 cases, 71.4%). While there was a trend toward increased microvascular complications with the use of irradiated recipient vessels (27 cases, 96.4%), this did not reach statistical significance (OR = 1.98, p = 0.52). The use of perforating branches as recipient vessels did not confer an increased risk of microvascular complications (OR = 0.87, p = 0.75).

Conclusion:  The reconstruction of irradiated lower-extremity STS defects represents a particularly challenging issue. This analysis demonstrates that free tissue transfer can be safely performed using irradiated vessels without a significantly increased risk of microvascular complications. Furthermore, unnamed perforating branches can be successfully used for reconstruction in anatomically challenging areas of the lower extremity.