A modified induced membrane 2-stage technique using a thoracodorsal artery perforator free flap followed by vascularized or non-vascularized free fibular transfer for the treatment of complex bone infection with concomitant severe soft tissue lesion-A case series of 9 cases

Abstract

Treatment of post-traumatic complex bone infection is very challenging. The two principal bone reconstruction approaches are the single-stage vascularized bone graft technique and the two-stage induced membrane technique (IMT). Here we introduce a modified 2-stage induced membrane technique (MIMT) for complex long bone infection with a major bone defect and a concomitant severe soft tissue lesion. The 2-stage procedure consists of bone debridement, placement of a PMMA spacer and soft tissue reconstruction with a thoracodorsal artery perforator free flap ("Tdap") at stage 1. At stage 2, the thoracodorsal artery perforator flap is elevated and a fibular strut graft (either vascularized of non-vascularized) is placed for bone reconstruction. We retrospectively analyzed the extents of lower extremity, long bone, post-traumatic bone infection treated via MIMT from 2008 to 2020. There were nine such cases (eight males) of mean age 59.8 (range 31 to 79) years. The osteomyelitis durations ranged from 3 to 360 months (mean 53 months). The cortical bone defect sizes was ranged from 9 to 14 cm (mean10.7 cm). All skin resurfacing employed Tdap. Vascularized fibular grafts were placed in six patients and non-vascularized grafts were placed in three. The fibular graft size ranged from 12.5 to 19 cm (mean 16.2 cm). Non-vascularized iliac bone grafts served as the fibula docking sites. Unfortunately, all patients suffered complications before bone union was achieved. One case of plate stress fracture and one case of screw fracture required plate and screw change. In three cases of cellulitis, one resolved by use of intravenous antibiotics, others required plate and screw removal. Wound disruption required re-suture and distal skin flap partial necrosis was covered by perforator-based island flap. One case of fibular stress fracture needed cast for 4 weeks. A peroneal nerve palsy patient recovered spontaneously. Bone union was achieved after 6 months in five patients and after 8 months in three (mean 6.9 months). All patients were able to walk unaided. The follow-up period ranged from 2 to 14 years (mean 6.2 years). MIMT saves the limbs in cases with difficult post-traumatic bone infection. It is valid treatment option for complex bone infections with severe soft tissue lesions. However, even with this technique potential complication must be considered.

Keywords: Free tissue transfer; Induced membrane technique; Osteomyelitis; Reconstruction.