Case 19 2026: Split Perforator Flaps for bilateral ankle defects: A modern microsurgical approach to preserve function and reduce secondary thinning operations

Luisa Lotter¹; Marta Jezierska¹; Ilja W. Käch¹; Volker J. Schmidt¹

Journal of Plastic, Breast & Reconstructive Surgery·Peer-reviewed, open-access surgical case reportsPeer-reviewed · Open access

Case 19 2026: Split Perforator Flaps for bilateral ankle defects: A modern microsurgical approach to preserve function and reduce secondary thinning operations · JPBRS

Case report

Case 19 2026: Split Perforator Flaps for bilateral ankle defects: A modern microsurgical approach to preserve function and reduce secondary thinning operations

Luisa Lotter¹¹, Marta Jezierska¹¹, Ilja W. Käch¹¹, Volker J. Schmidt¹¹

¹Hospital St.Gallen, St.Gallen, Switzerland

Published May 28, 2026954 views7 min read

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Abstract

46-year-old man presented with two full-thickness soft-tissue defects of the distal right lower leg (medial 7 × 4 cm, lateral 10 × 5 cm) with exposed tendons, osteosynthesis material, and bone after a Gustilo grade IIIb open tibial and fibular fracture. During initial orthopedic stabilization, interdisciplinary orthoplastic assessment and planning were performed. Because of exposed functional structures and two spatially separated defects with healthy anterior skin between them, microsurgical free-tissue reconstruction was chosen to provide stable coverage while preserving the anterior skin and preventing flap-related functional impairment. Reconstruction was achieved using a split anterolateral thigh (ALT) flap based on two independent perforators, enabling simultaneous coverage of both defects with a single vascular pedicle. Patient medical history The patient’s medical history was significant for type 2 diabetes mellitus, two-vessel coronary artery disease, and obesity. Before and After Patient examination Clinical assessment revealed two full-thickness defects at the distal lower leg: • medial defect: 7 × 4 cm with exposed tendons • lateral defect: 10 × 5 cm with exposed bone and osteosynthesis material Both wounds showed non-viable soft-tissue components requiring radical surgical debridement prior to reconstruction. An CT-angiography was performed, revealing a regular three-vessel supply to the affected lower right leg. Preoperative color-duplex-ultrasound was routinely performed to identify the ALT perforator pattern and to verify, if a two-perforator split ALT-fashion is possible. Due to our tertiary orthoplastic program final interdisciplinary reconstruction was schedule

Key learning points

Pearls

• A perforator-based split ALT flap enables simultaneous subunit reconstruction of multiple adjacent lower-leg defects using a single vascular pedicle.
• Split ALT flaps can preserve healthy and functional relevant skin territories that were in former times often covered with larger and bulky muscle flaps
• Split flaps for multiple and distant lower extremity defect reconstructions with an end-to-site arterial anastomosis pattern enable optimal preservation of the distal extremity vessel axis
• A careful colour duplex examination for perforator localization is ideally performed by the surgeon one day before the operation the final flap design should locate each perforator after division of the flaps at the transition from the proximal to the middle third of the flap
• Intraoperative ICG-perfusion mapping should be used to minimize the risk of distal flap necrosis
• Documentation of the flap rotation ankle and direction (clockwise or anticlockwise) for each pedicle within the operation report is crucial, if revision surgery is required.
• Embedding the pedicels into fibrin glue minimizes the risk for pedicle torniquet and tension.

Pitfalls

• A lack of sufficient independent perforators during the colour duplex examination demands an alternative reconstructive plan (e.g. two separate flaps of split latissimus dorsi flap in this case)
• Distal lower-leg reconstruction requires meticulous preparation of recipient vessels, as vessel quality may be compromised after severe trauma. In older patients (>50y) and in younger patients with a risk profile for atherosclerosis an adequate recipient vessel assessment should be performed (e.g. CT- or MR-angiography).
• Lower extremity traumas are associated with a significant rate of clinically occult deep vein thrombosis. The vascular examination should be generously supplemented with an assessment of the deep venous system in case of suspicion.
• Excessive tension or pedicle twisting during rotation of split skin islands can lead to vascular compromise.
• Progressive tunnelling of the pedicle/s should be avoided if secondary edema or swelling is likely.

Donor site in anterolateral thigh (ALT) free flaps: A systematic review of closure techniques and introduction of a management algorithm Chang, Chad et al. Journal of Plastic, Reconstructive & Aesthetic Surgery, Volume 105, 243 - 259Split anterolateral thigh free flaps for bilateral open fracture ankle defects: A one donor, two flap solution, Wilson, Elizabeth et al. JPRAS Open, Volume 46, 2025, Pages 61-64

Patient history

The patient’s medical history was significant for type 2 diabetes mellitus, two-vessel coronary artery disease, and obesity.

Examination

Clinical assessment revealed two full-thickness defects at the distal lower leg:
• medial defect: 7 × 4 cm with exposed tendons
• lateral defect: 10 × 5 cm with exposed bone and osteosynthesis material
Both wounds showed non-viable soft-tissue components requiring radical surgical debridement prior to reconstruction.
An CT-angiography was performed, revealing a regular three-vessel supply to the affected lower right leg. Preoperative color-duplex-ultrasound was routinely performed to identify the ALT perforator pattern and to verify, if a two-perforator split ALT-fashion is possible. Due to our tertiary orthoplastic program final interdisciplinary reconstruction was scheduled within 7 days after the initial trauma to reduce the risk for secondary complications (e.g. osteomyelitis).

Pre-operative considerations

Reconstruction of distal lower-leg defects with exposed hardware and tendons requires durable vascularized soft-tissue coverage to prevent infection and ensure limb salvage.
The following considerations guided reconstructive planning:
1.tTwo separate defects in close proximity and including the two ankle subunits are associated with functional loss if larger one-flap solutions (e.g., latissimus dorsi) are applied.
2.tPreservation of the intact and functional relevant anterior soft tissue bridge should be taken into consideration
3.tEither two independent flaps (e.g., SCIP or ALT) or a single flap capable of division into multiple components are suitable options.
4.tMuscle flaps are not optimal if further orthopedic interventions are required in the future (lower vascular randomization compared to fasciocutaneous flaps)
5.tThe ALT flap offers a long vascular pedicle, reliable perforators, and sufficient tissue volume while permitting intraflap splitting when multiple perforators are present.
6.tA perforator-based split ALT flap allows simultaneous coverage of spatially separated defects while avoiding multiple donor sites.
7.tRecipient vessel preparation focused on the anterior tibial artery and venae comitantes to ensure reliable inflow and venous drainage.

References

Donor site in anterolateral thigh (ALT) free flaps: A systematic review of closure techniques and introduction of a management algorithm Chang, Chad et al. Journal of Plastic, Reconstructive & Aesthetic Surgery, Volume 105, 243 – 259
Split anterolateral thigh free flaps for bilateral open fracture ankle defects: A one donor, two flap solution, Wilson, Elizabeth et al. JPRAS Open, Volume 46, 2025, Pages 61-64

Post-operative plan

• Strict limb elevation and bed rest were maintained for five postoperative days. Flap perfusion was monitored hourly for the first 24 hours and at regular intervals thereafter.
• A structured dangling protocol was initiated from postoperative day 5 to gradually condition venous outflow.
• The patient was immobilized in a custom splint with protected partial weight-bearing of 15 kg for six weeks due to the underlying osteosynthesis. A pressure-relieving recess was incorporated over the flap to avoid compression and prevent equinus deformity.

• Low-molecular-weight heparin anticoagulation and intravenous antibiotics were administered according to institutional microsurgical protocol and adjusted to microbiological results.
• Compression therapy was continued for six months, with scheduled outpatient follow-up at regular intervals.

How to cite this article

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Step 1 — Radical wound bed preparation and hardware assessment

Step 2 — Preparation of the recipient site

Step 3 — Flap dissection

Step 4 — Microsurgical anastomoses and flap splitting

Step 5 — Flap inset

Post-operative plan

Pearls

Pitfalls