Bilateral Lumbar Artery Perforator (LAP) Flaps for Extensive Lumbosacral Defects: A Report of Two Cases.

Extensive lumbosacral defects remain a major reconstructive challenge because of limited regional tissue mobility, contamination risk, proximity to neural structures, and frequent association with prior surgery or spinal instrumentation. Although lumbar artery perforator (LAP) flaps are recognized as muscle-sparing options for posterior trunk reconstruction, their capacity to safely reconstruct very large midline lumbosacral defects and their applicability in rare adult presentations of lumbosacral myelomeningocele remain insufficiently defined. We report two adult female patients who underwent reconstruction of extensive midline lumbosacral defects using bilateral pedicled LAP flaps to illustrate the applicability of this approach in exceptionally large post-instrumentation and adult dysraphic defects. The first patient, a 19-year-old woman, presented with a 36 × 28 cm post-instrumentation defect with exposed L4-S1 hardware following multi-trauma and repeated soft-tissue necrosis. After serial debridements and prolonged culture-directed intravenous antibiotic therapy, bilateral LAP flaps measuring 22 × 12 cm were elevated based on bilateral L4 perforators identified by computed tomography angiography and Doppler ultrasonography. The second patient, a 28-year-old paraplegic woman with spina bifida, presented with recurrent cerebrospinal fluid leakage associated with a 22 × 16 cm lumbosacral myelomeningocele defect. Following neurosurgical dural repair, bilateral LAP flaps measuring 18 × 10 cm were harvested based on medially displaced L4 perforators. In both cases, the flaps were designed according to defect geometry and perforator location, then rotated approximately 90° medially to achieve tension-reduced midline closure while facilitating primary donor-site closure. Complete flap survival was achieved in both patients without venous congestion or total flap loss. In the first case, limited wound dehiscence related to hardware prominence was successfully revised with a local V-Y advancement flap, and a small donor-site tension area was managed with split-thickness skin grafting. In the second case, a limited lateral donor defect also required split-thickness skin graft coverage. At 13 months, spinal instrumentation was electively removed in the first patient after adequate osseous stabilization, while flap stability was preserved. At 15 and 9 months of follow-up, respectively, both patients demonstrated durable soft-tissue coverage without recurrent breakdown or cerebrospinal fluid leakage. These cases suggest that bilateral pedicled LAP flaps may facilitate stable, muscle-sparing reconstruction in selected extensive lumbosacral defects, including exceptionally large post-instrumentation wounds and rare adult presentations of lumbosacral myelomeningocele.