Lumbar Fusion in Achondroplasia Does Fusion to the Sacrum Affect Function?

Background: Stenosis and kyphosis are common in achondroplasia, often requiring lumbar fusion, sometimes to the sacrum. The purpose of this study was to determine the functional effect of lumbar fusion to the sacrum in patients with achondroplasia. Methods: Functional and SF-36 questionnaires were sent to the 66 patients with achondroplasia who underwent instrumented lumbar fusion at our institution from 1991 to 2006. Of the 35 who returned questionnaires, 13 had fusions to the sacrum and 22 did not. Chi-square analysis and a t test were used to evaluate outcomes. Significance was set at P<0.05 or a 95% confidence interval that did not cross 1. Results: There were no statistical differences in SF-36 scores. There was a trend toward more pain in the group fused to the sacrum (P=0.1). There were no statistically significant differences in difficulty with activities, but there was a trend toward increased difficulty with hygiene after toileting in the group with fusion to the sacrum (odds ratio: 3.76, confidence interval: 0.53-26.87, P=0.19). Conclusions: Fusion to the sacrum did not significantly affect function in patients with achondroplasia, although there was a trend toward increased pain and greater difficulty with hygiene after toileting.