Risk factors for supplementary posterior instrumentation after anterolateral decompression and instrumentation in thoracolumbar burst fractures

• Anterolateral decompression and instrumentation (ALDI) for thoracolumbar burst fractures (TLBF) can be accomplished safely with a favorable neurological outcome.
• Stand-alone ALDI for TLBF is sufficient in 90% of such patients.
• Age was the only significant risk factor predicating supplemental posterior instrumentation after ALDI.

BackgroundIn spite of the established benefits of anterolateral decompression and instrumentation (ALDI) for thoracolumbar burst fractures (TLBF), the indications for supplementary posterior instrumentation remain unclear.MethodsA retrospective review of clinical and radiographic data of a prospective cohort of 73 patients who underwent ALDI for TLBF from T12 to L4.ResultsThe mean age of the cohort was 42 ± 15 years, with 49 males and 24 females. Forty-six patients had neurological deficit, and 27 were intact. Owing to symptomatic settling, supplemental posterior instrumentation was performed in 7 out of 73 patients. The age of patients requiring supplemental posterior instrumentation (59 ± 14 years) exceeded that of patients who did not (41 ± 16, p = 0.004). Otherwise, the patients who required posterior instrumentation were comparable to those treated with ALDI in terms of body mass index (BMI), American Spinal Injury Association (ASIA) scores on admission and follow-up, residual spinal canal, and local kyphosis on admission and follow-up.The posterior ligamentous complex (PLC) integrity was assessed in 38 patients in whom the MRI scans were retrievable, 31 successfully treated with ALDI, and all 7 undergoing supplementary posterior instrumentation. Subgroup analysis demonstrated that there was no difference in the incidence of PLC disruption between the 2 groups (p = 0.257).ConclusionsSecondary supplemental posterior instrumentation was deemed necessary in 10% of cases following ALDI. Age was the only significant risk factor predicating supplemental posterior instrumentation.