Advancing pure skin perforator flaps: Microscope-free harvesting, versatile donor sites, and outcomes

Authors: Bae J, Lee J-K, Lee K-T.

Affiliation: Dept. of Plastic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.

Journal: Plastic and Reconstructive Surgery, December 2025.

PMID: 40403284.

Key takeaways

• Pure skin perforator (PSP) flaps were harvested with loupes only (3.5×) using a distal-to-proximal technique and ultra high frequency ultrasound.

• In 71 flaps (55 SCIP, 10 ALT, 6 TDAP): mean thickness ~3.5 mm, harvest time ~37 minutes, and pedicle length ~4.8 cm; TDAP were thickest/longest, SCIP thinnest/shortest.

• Overall complications 25.4%; flap loss 8.5% (total 2.8%, partial 5.6%). Delayed healing (19.7%) predominated.

• Complication risk rose when flap size exceeded 25.4 cm² (40.5% vs 8.7%; ROC AUC 70.5%). Older age, active smoking, and larger flaps independently increased risk.

• Donor-site choice by indication: SCIP for digits/thin skin with nearby vessels; ALT/TDAP for thicker dermis or when a longer pedicle is needed.

Background

Thin, durable vascularized coverage is challenging for shallow but complex defects over bone or tendon, where conventional perforator flaps may be too bulky. PSP flaps leverage minute perforators and the subdermal plexus to deliver ultrathin skin paddles.

Objective

Evaluate PSP flaps’ harvesting feasibility without a microscope, optimal donor-site selection, and clinical outcomes across indications.

Methods

• Design and setting: Single-center retrospective series of consecutive PSP free flaps (April 2021–January 2024).

• Population: 71 patients; mean BMI ~24 kg/m². Donor sites: SCIP (n=55), ALT (n=10), TDAP (n=6).

• Indications and wound beds: Oncologic resections 90.1%; chronic wounds 8.5%. Wound beds: cartilage/bone 59.2%, tendon 12.7%, subcutaneous 28.2%.

• Technique: High-frequency ultrasound (22 MHz) used for perforator mapping; distal-to-proximal dissection under loupes (3.5×). A thin fat lobule was retained when contour was needed.

• Endpoints: Harvest metrics (time, thickness, pedicle length), flap and donor complications, multivariable regression for risk factors; ROC-derived size cutoff; learning-curve (CUSUM) analysis.

Results

• Harvest performance: Mean harvest time 37 minutes. Median thickness 3.5 mm; most flaps based on a single PSP.

• Pedicle and geometry: TDAP pedicles longest, SCIP shortest; TDAP thickest, SCIP thinnest.

• Operative time (overall case): Mean 244 minutes (range 165–365).

• Complications (n=71): Any flap-related 25.4%; flap loss 8.5% (total 2.8% [venous thromboses], partial 5.6%). Delayed healing 19.7%, infection 5.6%, hematoma 2.8%; flap-related reoperations 12.7%. Donor-site complications 11.3%. Rates did not differ by flap type.

• Risk factors: On multivariable analysis, age (adjusted OR 1.08 per year; P=0.041), active smoking (adjusted OR 11.32; P=0.012), and larger flap size independently predicted flap-site complications.

• Size threshold: ROC AUC 70.5%; a 25.4 cm² cutoff yielded 40.5% complications above vs 8.7% below (P=0.003).

• Indication-based donor choice: SCIP favored for digits/dorsal hand/toes; ALT/TDAP for plantar foot/lower leg or when longer pedicles are required.

• Learning curve: Elevation time decreased from ~54 → 31 → 29 minutes across learning → proficiency → competency phases, with declining complications after ~15–31 cases.

Conclusion

PSP flaps provide ultrathin, reliable coverage for shallow but complex defects and can be safely harvested from multiple donor sites when surgeons apply indication-based selection and avoid oversized skin paddles.

Strengths and limitations

• Strengths: Largest PSP series to date (n=71); standardized loupes-only technique; identification of a practical size cutoff and independent risk factors; pragmatic donor-site algorithm.

• Limitations: Single surgeon, retrospective design; relatively low BMI, predominantly Asian cohort; limited assessment of perforator caliber and preoperative imaging sensitivity for PSPs.

Clinical relevance

• Consider PSP flaps when skin grafts are inadequate but flap bulk would impair function or aesthetics (digits, ankle, joints).

  • Must be willing to accept higher flap failure and delayed wound healing rates

• Choose donor site by need: SCIP for thin skin and short reach; ALT/TDAP for thicker skin or longer reach.

• Keep paddles at or below ~25 cm² when feasible; if larger area is essential, consider multiple PSPs, staged coverage, or alternative flaps—especially in smokers or older patients.

Critiques and questions

• Perfusion biology: Failures likely relate to the PSP’s reliance on the subdermal/deep dermal plexus after superthin elevation, making outcomes sensitive to skin paddle size. Future work should quantify PSP flow (e.g., ICG angiography, speckle flowmetry) and correlate with outcomes.

• Generalizability: Results come from one high-volume team with a learning curve flattening by roughly 30 cases. Centers new to PSP should anticipate higher early risk and adopt a proctored pathway with conservative case selection (SCIP for small digital defects first).

• Imaging: High-frequency ultrasound aided perforator selection; current CTA protocols an pencil doppler are likely inadequate.