Demirdover bilaminar gluteal flap (DF) — layered repair for large sacral defects

Demirdover et al. Plast Reconstr Surg Glob Open, 2025; retrospective case series (Level IV evidence); PMID 40469547.

Concept & indications - The DF is a two‑layer advancement flap that recruits both gluteus maximus muscle and an overlying fasciocutaneous flap on each side of the midline. It obliterates deep dead‑space and resurfaces post‑sacrectomy wounds with exposed bone and rectum while sparing gait function. Suitable for large midline defects (i.e. post chordoma resection).

Key anatomic points

Gluteus maximus	Medial third released from underlying piriformis & gluteus medius to allow midline approximation; insertions usually left intact to preserve hip extension.
Superior & inferior gluteal arteries	Main pedicles; perforators concentrated in predictable zones that must be protected.

Operative steps (prone position)

1. Perforator mapping – Hand‑held Doppler marks SGA and IGA perforators before incision. 

   1. Superior gluteal perforators: Draw a line from the posterior superior iliac spine (PSIS) to the greater trochanter; superior gluteal artery (SGA) perforators cluster along the medial one‑third of this line.

   2. Inferior gluteal perforators: Draw a horizontal line parallel to the gluteal fold ~5 cm above it; inferior gluteal artery (IGA) perforators are concentrated in the middle third of the buttock on this line.

2. Muscle layer – Medial gluteus maximus edges (already detached by sacrectomy) are dissected laterally; nerves & pedicles preserved. Tension‑free midline apposition is achieved; partial lateral release if needed.

3. Fasciocutaneous layer – Skin flap elevated (superficial to deep fascia), saving as many perforators (min. 3 per side) as able.

4. Relaxing incisions - If needed, crescent‑shaped cuts in the lateral gluteal border (perforator‑sparse zone) enhance mobility and reduce tension. Wounds closed primarily or skin grafted.

5. Layered closure -

   1. Deep : bilateral gluteus maximus muscles advanced and sutured together in the midline

   2. Superficial: bipedicled fasciocutaneous flaps advanced across the midline

6. Drains & positioning – Closed‑suction drains; patient prone with 45° rolling for one week, then gradual mobilization avoiding hip flexion.

Pearls & pitfalls

• Preserve most perforators; ligating too many risks ischemia.

• Avoid full detachment of gluteus maximus insertion in ambulatory patients.

• Place relaxing incisions lateral to main perforator zones.

• Layered design restores buttock contour and tolerates adjuvant radiotherapy.

Post‑operative outcomes (12‑patient series)

No flap failures; one superficial abscess managed with drainage/debridement. Mean follow‑up ≈ 21 months.

Note on nomenclature

While the authors label this the “Demirdover flap,” the operation is essentially a bilaminar gluteal advancement (muscle plus overlying fasciocutaneous) — a concept previously described in various forms. Eponymous names can obscure the underlying anatomy and make cross‑study comparisons harder; a descriptive term such as “bilaminar gluteal advancement flap” may serve the field better.

Clinical Relevance

The bilateral gluteal advancement flap provides reconstructive surgeons with another option in their toolkit to reconstruct large sacral defects. It would be interesting to compare this technique with V-Y advancement flaps as well as evaluating strength/ambulation outcomes further.