Microvascular injury and regional perfusion vulnerability during recipient site creation in hair transplantation

Recipient site scalp necrosis (RSN) is a rare but potentially devastating complication of hair transplantation that can result in permanent tissue loss and graft failure. Although factors such as excessive graft density, deep implantation, infection, and pharmacologic vasoconstriction have been proposed, these explanations do not fully explain the observed regional predilection of ischemic complications in the frontal and mid-scalp. In this narrative review, we propose a unifying, anatomy-driven framework to explain RSN based on regional vascular vulnerability and cumulative microvascular injury. We focus on the distal course of the frontal branch of the superficial temporal artery, which often travels superficially with substantial interindividual variation, creating patient-specific high-risk vascular zones in the frontal scalp. We further explore how incision geometry, instrument-related injury patterns, and cumulative incision burden – particularly in the frontal tuft – may interact with regional perfusion reserve to precipitate ischemic breakdown. Rather than presenting definitive causal claims, this review synthesizes clinical observations, anatomical principles, and procedural mechanics to generate testable hypotheses. By reframing RSN through a perfusion-conscious perspective, this work aims to inform safer recipient site design while preserving aesthetic outcomes in modern hair transplantation.