Evolution of Reconstructive Microsurgery: 5,113 Free Flaps, One Surgeon, Four Decades

The evolution of reconstructive microsurgery is often described in terms of technical innovation and flap survival, yet external forces shaping reconstructive demand have rarely been formally quantified. Here we evaluate how surgical innovations (introduction of ALT and fibula flaps) and safety legislation impacted practice patterns across four decades. Methods: Time-trend analysis of 5,113 consecutive free flaps (1981-2023) from a single surgeon at Chang Gung Memorial Hospital, using segmented regression and joinpoint modelling. Results: 5,113 free flaps included 1,927 ALT, 946 fibula, 1,010 toe transfers, 469 radial, 232 latissimus dorsi and 67 gracilis. Innovations: ALT introduction was associated with explosive growth (+ 21 flaps/year; p=.003, 1996 to 1999) and rapid substitution of competing soft tissue flaps, with declines in LD, gracilis, and radial forearm. Fibula showed a much slower uptake, with joinpoint models showing moderate growth (+ 2.13 flaps/year; P<.001) until repurposing for mandible reconstruction in 1989. This subsequently correlated with increased site-specific use and tracking of oral cancer incidence (incidence rate ratio = 1.05, p <0.001). Legislation: Toe transfers declined after national Safety Legislation in 1991, with a 4-year lag (-33.7, P <.001). Conclusions: Microsurgical practice evolves through both technical advances and external forces such as health policy. The contrasting trajectories of the ALT and fibula flaps highlight how innovations reshape reconstructive practice differently. External drivers such as legislation can impact on microsurgical need such as toe transfers. Together these underscore the need for long-range horizons in surgical planning, and the need for intepreting time-trends alongside epidemiological shifts and health policy.