The role of fusion in degenerative lumbar disease

Abstract

P S d a c t n p t s t t r n the United States, approximately 151,000 lumbar spine fusions are performed per year.1 he majority of these fusions are performed for a ariety of degenerative conditions ranging from pondylolisthesis to degenerative disk disease DDD). Lumbar degenerative disorders are typially divided between those that cause mechanial back pain (ie, DDD) and those that cause adiating leg pain (ie, disk herniation or spinal tenosis). Treatment decisions, particularly those egarding fusion, must recognize that each of hese conditions represents a point on a continum rather than a discrete pathophysiologic enity. This continuum spans from asymptomatic desccation of the lumbar disk, to painful disk deeneration associated with mechanical pain, to arious neurocompressive lesions, including heriation and spinal stenosis, to marked lumbar nstability with multiplanar spondylolisthesis or egenerative scoliosis. More importantly, similar adiographic changes may occur in asymptomatic atients and are nearly universal in the aging pine. Therefore, defining the point when a raiographic finding becomes a pathologic state emains controversial, particularly in patients ithout neurocompressive symptoms. The goals of fusion in this patient population nclude (1) stabilization of scoliosis and sponylolisthesis, (2) to decrease pain by limiting mehanical stimuli to free nerve endings within the uter annulus and posterior longitudinal ligaent (PLL), and (3) to decrease the occurrence f laminar regrowth or recurrent stenosis. Alhough the use of lumbar fusion is increasing, the