Maintaining the “U” Pattern in the Donor Area During Follicular Unit Extraction in Hair Transplant Surgery - A Prospective Study

Abstract

Background

Follicular Unit Extraction (FUE) is a widely adopted technique for treating androgenetic alopecia (AGA), but donor area depletion and suboptimal outcomes remain concerns. The “U-pattern” donor zone has been proposed as a more anatomically stable harvesting area, though high-level evidence is lacking.

Aim

To maintain the U pattern in hair transplant surgeries. To evaluate the aesthetic and clinical outcomes of FUE restricted to the U-pattern donor zone compared to conventional extended harvesting.

methods

Study with reference number – IHEC/SDC/PhD/OMFS-2343/23/TH-092. Prospective, randomized controlled trial was conducted on 60 male patients with Norwood–Hamilton grade III–V AGA. Patients were randomized into two groups: Group A (control) underwent FUE from an extended donor area; Group B (test) had extraction limited to the U-pattern zone. Primary outcomes included aesthetic score and graft survival. Secondary outcomes comprised patient satisfaction, donor density loss, and visible scarring.

Results

Group B demonstrated superior results in all primary and secondary endpoints. The mean aesthetic score was significantly higher in Group B (7.90 ± 0.80) versus Group A (6.31 ± 1.00; p < 0.000001). Graft survival was 84.92% in Group B compared to 75.06% in Group A (p < 0.000001). Donor density loss was lower in Group B (10.61 FU/cm²) than Group A (13.82 FU/cm²; p = 0.000003). Patient satisfaction and visible scarring rates also favoured the U-pattern group.

Conclusion

restricting follicular unit extraction to the U-pattern donor zone resulted in significantly better graft survival, higher aesthetic scores, and improved patient satisfaction.

This approach also minimized donor density loss and visible scarring compared to conventional extended harvesting.

The findings validate the anatomical stability of the U-pattern as a reliable donor zone for long-term outcomes.
Thus, U-pattern–limited harvesting should be considered a preferred strategy in modern hair transplantation.