Reply: Matched Comparison of Microsurgical Anastomoses Performed with Loupe Magnification versus Operating Microscope in Traumatic Lower Extremity Reconstruction

Abstract

Background Although the surgical microscope remains the most common tool used for visual magnification for microsurgical anastomoses in free tissue transfer, loupe-only magnification for free flap breast reconstruction has been demonstrated to be safe and effective. To evaluate the loupe-only technique in lower extremity free flap reconstruction, the authors compared perioperative outcomes between microsurgical anastomoses performed with loupe magnification versus a surgical microscope. Methods The authors conducted a two-institution retrospective study of soft-tissue free flaps for traumatic below-knee reconstruction. Optimal subgroup matching was performed using patient age, defect location, flap type (muscle versus fasciocutaneous), and time from injury (acute, 30 days) for conditional logistic regression analysis of perioperative outcomes. Results A total of 373 flaps met inclusion criteria for direct matched comparison of anastomoses performed with loupe magnification (n = 150) versus a surgical microscope (n = 223). Overall major complication rates were 15.3 percent: take-back for vascular compromise, 7.8 percent; partial flap failure, 7.8 percent; and total flap loss, 5.4 percent. No differences were observed between the loupe and microscope groups regarding major complications (14.0 percent versus 16.1 percent; OR, 0.78; 95 percent CI, 0.38 to 1.59), take-back for vascular compromise (5.3 percent versus 9.4 percent; OR, 0.51; 95 percent CI, 0.19 to 1.39), any flap failure (13.3 percent versus 13.0 percent; OR, 1.21; 95 percent CI, 0.56 to 2.64), partial flap failure (7.3 percent versus 8.1 percent; OR, 1.04; 95 percent CI, 0.43 to 2.54), and total flap loss (6.0 percent versus 4.9 percent; OR, 1.63; 95 percent CI, 0.42 to 6.35). Conclusions Perioperative complication rates, take-backs for vascular compromise, partial flap losses, and total flap failure rates were not significantly different between the matched loupe and microscope groups. Overall microsurgical success rates in traumatic lower extremity free flap reconstruction appear to be independent of the microsurgical technique used for visual magnification. Clinical question/level of evidence Therapeutic, III.