Recent Advances In Nucleus Pulposus Replacement Technology

Degenerative intervertebral disc disease is a common cause of back pain. Although back pain often resolves with physical therapy and anti-inflammatory medications, some patients fail conservative treatment and require surgical intervention. Nucleus pulposus (NP) replacement offers a less invasive alternative to discectomy with fusion, and avoids adjacent level degenerative disease. New NP replacement materials have been under active investigation for over a decade. In this article we review progress in NP replacement technology made over the past 2 years. Most types of implants are either inserted in a dehydrated form and then swell to fill the NP cavity, or are injected into the NP cavity as a liquid, which are then induced to gel. Recent biomechanical, in vitro, in vivo, and clinical studies continue to improve the safety and efficacy of NP replacement technology. The major complications of NP replacement are extrusion through the annulus and subsidence through the endplates. Although progress has been made toward making NP replacement a safe and effective clinical tool, NP replacement remains investigational, and more well-designed prospective randomized control trials are needed before NP replacement can become a routine therapeutic alternative.