Minimally invasive transforaminal posterolateral approach for lumbar fractures of AO type A3 compli-cated with neurological deficits

Abstract

Objective To investigate the clinical efficacy of minimally invasive transforaminal pos-terolateral approach (MI-TPLA) for lumbar fractures of AO type A3 complicated with neurological deficits. Methods From January 2010 to January 2013, 17 patients with lumbar fracture of AO type A3 complicated with neurological deficits were treated with neural tissue decompression through MI-TPLA, bone grafting within the injured vertebra and percutaneous pedicle screw fixation. They were 11 males and 6 females, 21 to 63 years of age (average, 45.7 years). Fracture occurred at L1 in 7 cases, at L2 in 6, at L3 in 3, and at L4 in one. According to Frankel grading system, the neurological status was evaluated as grade A in one case, as grade B in 2 cases, as grade C in 9, and as grade D in 5. Intraoperative blood loss, operation time and complications were recorded. Lumbar cobb angle and anterior height of injured vertebra were observed on lateral X-ray films. The ratio of canal median sagittal diameter occupied and the ratio of cross-section area occupied were measured and calculated at the maximally stenosed level on axial CT. Results All oper-ations were successfully completed. The operation time was 156.7 min (from 120 to 200 min), and the intra-operative blood loss was 280.9 mL (from 100 to 450 mL). All the patients were followed up for 24 months. The cobb angle reduced significantly from preoperative 26.8°±3.6° to postoperative 2.6°±1.7° (P<0.05). The anterior height ratio of injured vertebra restored significantly from preoperative 56.3% ±14.6% to postoper-ative 93.7% ±6.0% (P<0.05). The ratio of canal median sagittal diameter occupied and the ratio of cross-section area occupied significantly improved from preoperative 52.8% ±4.4% and 52.3% ±7.6% to postoperative 96.3% ±2.3% and 82.9% ±12.1% , respectively (P<0.05). At the final follow-up, im-provement in Frankel grade was observed in all the patients, with grade B in one case, grade C in one, grade D in 7 cases and grade E in 8. Conclusion MI-TPLA is less invasive, safe and effective for lumbar fractures of AO type A3 complicated with neurological deficits. Key words: Lumber vertebrae; Fractures, bone; Surgical procedures, minimally invasive; Neurological deficits