Ghogawala Z, Benzel EC, Amin-Hanjani S, Barker FG, Harrington JF, Magge SN, Strugar J, Coumans JV, Borges LF. Prospective outcomes evaluation after decompression with or without instrumented fusion for lumbar stenosis and degenerative Grade I spondylolisthesis. J Neurosurg Spine. 2004 Oct; 1(3):267-72.