Donor Site Preservation and Long-Term Management in Follicular Unit Extraction (FUE): A Structured Clinical Framework for Surgical Planning and Complication Prevention

Background: Follicular unit extraction (FUE) has become the dominant donor site harvesting technique in modern hair transplantation due to its ability to avoid linear scar formation and its procedural flexibility. However, the donor site is a limited non-regenerative source. Excessive or poorly planned extraction can lead to visible thinning, hypopigmented scarring, and reduced reserve for future procedures. Objective: This study aimed to synthesize current evidence on donor biology, preoperative assessment, extraction strategy, and complication prevention in FUE, and to propose a reproducible clinical framework for donor preservation. Methods: A structured narrative review was conducted using PubMed/MEDLINE, Scopus, and Google Scholar to identify English-language publications related to donor site biology, donor evaluation, extraction density thresholds, complication prevention, repeat session planning, and emerging FUE technologies. Priority was given to recent reviews, clinical trials, consensus statements, and practice-oriented surgical literature. Articles were selected not for formal meta-analytic pooling, but because of their relevance to donor conservation and long-term donor management. Results: The literature reviewed consistently identifies excessive local extraction density, harvesting beyond conservative limits, donor miniaturization, and inadequate reassessment before repeated procedures as the primary drivers of donor morbidity. Evidence from reviews, clinical trials, and expert guidelines supports conservative extraction thresholds, widespread spatial distribution, individualized donor mapping, and phased long-term planning as key strategies for preserving donor aesthetics and reserve. Conclusions: Donor preservation is central to ethical and sustainable FUE surgery. Integration of biologically informed assessment, disciplined extraction control, and mandatory reassessment protocols can reduce morbidity while preserving long-term graft flexibility in patients with progressive androgenetic alopecia.