Every implant-based reconstruction is a bet on the mastectomy flaps. Mastectomy skin flap necrosis is the complication that turns good operations bad: it exposes devices, delays adjuvant therapy and undoes envelopes that can never be fully rebuilt. This professional overview covers the risk factors, the assessment tools including indocyanine green angiography, and the intraoperative decisions that flap quality should drive.

Why flaps fail

The mastectomy flap survives on the subdermal plexus. Necrosis follows when that plexus is too thin, too damaged or too stretched: overly aggressive dissection, flaps thinned past the oncologically necessary plane, excessive tension from an over-ambitious implant, and systemic factors that compromise microcirculation. The recurring patient-level risk factors across published series are smoking, high BMI, diabetes, prior irradiation and large breast size; the recurring surgical factors are flap thickness, incision choice and device volume.

Clinical assessment and its limits

Experienced surgeons read flaps continuously: colour, capillary refill, dermal bleeding from the cut edge, warmth. Clinical judgement, however, is documented to overestimate perfusion in a meaningful fraction of cases, particularly in the pale, adrenaline-infiltrated field of a fresh mastectomy. That gap between how a flap looks and how it is perfused is exactly where objective tools earn their place.

Indocyanine green angiography

Intraoperative ICG angiography injects a fluorescent dye and images its arrival in the flap in real time, mapping perfusion while decisions can still be changed. Studies and systematic reviews report that ICG-guided assessment identifies poorly perfused zones more reliably than clinical examination and is associated with reduced necrosis rates when its findings actually change management: trimming compromised edges, reducing implant volume, or converting a planned direct-to-implant into a staged expander reconstruction. The tool has costs and false positives, and protocols vary; its value is greatest exactly where the stakes are highest, in nipple-sparing mastectomy and single-stage reconstruction.

Decisions flap quality should drive

When necrosis happens anyway

Management is graded to depth and device exposure: superficial epidermolysis is dressed and watched; full-thickness necrosis over an implant is debrided early, because the race between granulation and device exposure is rarely won by waiting. Salvage rates are meaningfully better when intervention is early and the pocket remains uncontaminated. Every unit’s protocol differs in detail; the shared principle is that necrosis declared early and managed actively costs an edge, while necrosis denied costs the reconstruction.

The bottom line

Flap perfusion is the single variable that should shape every intraoperative reconstruction decision. Assess it honestly, augment judgement with objective imaging where available, and let the flaps choose the operation. The reconstructions that fail are rarely the ones where the team was too cautious.

Key published sources