Decompression Versus Decompression and Fusion

Patients will undergo decompression alone of the supradjacent level. The surgical technique will be surgeon dependent. All surgeons will be encouraged to avoid damaging facet joints above the fusion mass, retaining 50% of the pars of the decompressed level and performing as minimal of a medial facetectomy as necessary.

Patients will undergo decompression and extension of posterior instrumentation and fusion. This may or may not include exchange of pre-existing instrumentation. The use of interbody cages will be left to the discretion of the treating surgeon. The purpose of introducing this heterogeneity is to increase the generalizability of the trial results. The fusion cohort will not utilize bone morphogenetic protein products.