Abstract
Introduction
Extreme lateral interbody fusion (XLIF) has been popular as a safe and reproducible method to obtain minimally invasive anterior spinal fusion. Autogenous bone, commonly from the iliac crest, constitutes ideal grafting. However, the amount of iliac crest bone available is limited and its harvesting is associated with significant donor site morbidity. Recently a porous hydroxyapatite/collagen (HAp /Col) composite has been developed as a substitute for conventional corticocancellous autografts. The aim of this study is to investigate the efficacy of a porous HAp /Col composite for XLIF.
Material and Methods
From November 2011, 15 consecutive patients (21 levels) underwent XLIF for lumbar degenerative diseases. In all cases, titanium cages filled with hybrid grafts using bone marrow aspirate (BMA) combined with a porous HAp/Co composite were inserted as intervertebral spacers and supplementary stabilization with posterior instrumentation were performed. In 4 cases (4 levels) pedicle screws (PS) were inserted unilaterally, and in 11 cases (17 levels) PS were inserted bilaterally. Fusion status was assessed using computed tomographic (CT) scans. A solid fusion was defined by the presence of bony bridging on 2 consecutive sections in at least 2 plains on CT imaging.
Results
At a follow up of 15.4months (minimum: 6 months), 66.7% of all patients (10 of 15) and 76.2% of all levels (16 of 21) were evaluated as solid fusion. In cases with bilateral PS, fusion rates were 81.8% of patients (9 of 11) and 88.2% of levels (15 of 17) respectively. Only one case with unilateral PS was evaluated nonunion due to PS loosening. No revision surgery for nonunion were requested.
Conclusion
Hybrid grafts using BMA combined with a porous HAp /Col composite were efficacious for XLIF as substitutes for conventional autografts. Rigid supplementary stabilization was considered necessary to obtain high fusion rates.