Introduction
Back pain is a leading cause for physician visits, with approximately 6080% of the US population experiencing episodes of acute low back pain at least once in their lives. While the majority of these patients improve with conservative care, a significant number become chronically debilitated and require surgical intervention. Historically, these patients are treated with fusion in lumbar spine or discectomy in cervical spine. Total disc replacement provides spine surgeons a proven alternative. Just like knee and hip arthroplasty, motion preservation of the spine is expected to make a significant impact on the surgical treatment of degenerative disc disease (DDD).

ProDisc
ProDisc was developed using the ball and socket concept successfully used in joint replacement implants for over 40 years. The ProDisc ball and socket implant design has been used clinically since 1990 and continues to demonstrate excellent long-term clinical results.
The ProDisc surgical technique, instrumentation, and implant function as a unified system. It provides a safe and reproducible implantation through a midline, mini open anterior approach. The implant is comprised of three implant componentstwo cobalt chrome alloy (CoCrMo) endplates, and an ultra-high molecular-weight polyethylene (UHMWPE) inlay. These materials have a long-term history of safe and effective use in joint replacement, which in the case of hips and knees is a much more demanding mechanical application.

ProDisc-L
Patients with degenerative disc disease (DDD) in lumbar spine are often treated with spinal fusion. While some patients do well after fusion, there are a significant number that do not find pain relief or go on to experience long-term degenerative changes from the rigid immobilization of their spine.

The ProDisc-L total disc replacement is indicated for spinal arthroplasty in skeletally mature patients with DDD at one level from L3-S1. DDD is defined as discogenic back pain with degeneration of the disc confirmed by patient history and radiographic studies. These DDD patients should have no more than grade 1 degenerative spondylolisthesis at the involved level. Patients receiving the ProDisc-L total disc replacement should have failed at least 6 months of conservative treatment prior to implantation of the ProDisc-L total disc replacement.

An FDA Investigation Device Exemption (IDE) clinical study with Pro-Disc-L was started in 2001 in the USA. The IDE study for single-level indications involved nearly 300 patients at 17 centers across the USA, comparing ProDisc-L to circumferential fusion. The study showed that ProDisc-L is a safe and reproducible procedure with a minimal learning curve. The patients were more satisfied with the ProDisc-L total disc replacement than fusion (81% satisfaction vs 69% for fusion). 94% of ProDisc-L patients had a normal range of motion at 24 months. ProDisc-L patients have significantly greater improvement in ODI scores than fusion patients (46% improvement over baseline vs 38% for fusion).