Pedicled Vascularized Bone Grafts for Posterior Lumbosacral Fusion: A Cadaveric Feasibility Study and Case Report

Abstract

Study design: Cadaveric feasibility study and case report.

Objective: To determine if it is feasible to rotate pedicled vascularized bone graft (VBG) from L1 to S1 via a posterior approach.

Summary of background data: VBG has been used to successfully augment fusion rates in various skeletal pathologies. Pedicled VBG has numerous advantages over free-transfer VBG, including the maintenance of a robust vascular supply to the graft without the need for vascular anastomoses. Pedicled VBG options have not been well described for posterior lumbosacral fusion.

Methods: A multidisciplinary team of plastic surgeons and neurosurgeons hypothesized that it is feasible to rotate pedicled VBG from L1 to S1 via a posterior approach. In six cadavers, two VBG donor sites were evaluated: posterior element (PE-VBG) and iliac crest (IC-VBG). A single case report of a patient with lumbar Charcot joint treated with IC-VBG is also presented.

Results: For the PE-VBG, the laminae and spinous processes were mobilized en bloc via Gill laminectomy on a unilateral sacrospinalis pedicle. Mean ± standard deviation (SD) length × width graft dimensions were 2.8±0.48 cm × 2.2±0.81 cm. The inter-transverse process (inter-TP) distance was less than the corresponding lamina length at all levels. For the IC-VBG, iliac crest was mobilized on a quadratus lumborum pedicle. Mean±SD length × width × thickness graft dimensions were 7.7±1.28 cm × 2.2±0.69 cm × 1.5±0.79 cm. The IC-VBGs reached from L1 (T12-S1) to S1 (S1-S3), and all IC-VBGs were able to cover three levels.

Conclusions: This feasibility cadaveric study and the case report are the first demonstrations that pedicled VBGs can be successfully applied to posterior lumbosacral spinal arthrodesis. Patients at high risk for nonunion may benefit from these strategies. Further clinical experience with these techniques is warranted.

Level of evidence: Level IV.

Keywords: Iliac crest graft; Pedicled bone graft; Posterior element graft; Posterior lumbosacral fusion; Vascularized bone graft.