Posterolateral lumbar fusion: Relationship between computed tomography Hounsfield units and symptomatic XXXX .

@entity1 @entity158 @entity1516
BACKGROUND: Assessment of bone quality can guide spinal surgery. However, surgeons infrequently evaluate bone quality in a quantitative manner. Recent literature suggests a role for computed tomography (CT) Hounsfield units (HUs) as a marker for bone quality. Limited data exist regarding its utility with respect to posterolateral lumbar fusion (PLF). METHODS: From fall 2010 to winter 2012, 10 @entity1 underwent revision surgery for symptomatic @entity1516 (defined as intractable @entity158 associated with either radiographic evidence of nonunion or intraoperative evidence of nonunion) after a prior L4-S1 PLF. These @entity1 were age-matched (  5 years) to 10 @entity1 who underwent L4-S1 PLF with no clinical signs of @entity1516 at 1-year follow-up. Available CT imaging (with or without instrumentation) was evaluated from L1 to L5 for the averaged HU. Data were pooled among L1-L3 values and between L4 and L5 values. RESULTS: Within the @entity1516 group, the pooled L1-L3 HU value was similar to the pooled L4-L5 HU value (168.39    22.84 HU vs. 166.98    23.20 HU respectively, P = 0.89). The same pattern was observed for the control group (190.24    37.13 HU vs. 201.89    36.59 HU respectively, P = 0.44). On the other hand, the pooled L1-L3 and L4-L5 HU values were larger for the control group compared to the @entity1516 group, with the pooled L4-L5 HU demonstrating statistical significance, P = 0.01. CONCLUSION: Currently, CT imaging is typically not obtained prior to lumbar fusion. Results demonstrated that CT HU values were significantly larger for @entity1 who did not exhibit symptomatic @entity1516 at 1-year follow-up compared to those who required revision surgery. As such, CT HU values may serve as a predictor for bony fusion to guide surgical management of @entity1 under consideration for PLF.
