Fusion Versus Disc Replacement for Discogenic Pain
Degenerative disease of the disc is one of the most frequently treated spinal conditions. Symptoms created by a degenerative cascade of the disc are related to the residual segmental mobility and the elimination of motion often resulting in pain relief, but at the cost of impaired function. The demand from both the clinicians and society for a better solution in the treatment of symptomatic degenerative disc disease beyond arthrodesis is universally increasing.
Spinal fusion became, very early, the gold standard of treatment for severe intervertebral disc pathologies. Although arthrodesis cages, implants, prepared allograft tissue/spacers, and other advances in spinal fixation and fusion biology have resulted in increased fusion rates, this technology fails to address the predictable pitfalls of segmental fusion itself. Interbody arthrodesis alters the normal disc structure, function, and can result in long term complications related to the biomechanical changes.
Spinal arthroplasty is quickly becoming a logical step in the treatment of severe degenerative disc disease [Figure 1]. The clear advantage of spine arthroplasty is its ability to restore and maintain the motion segmental anatomy and function, while successfully treating the patient's axial symptoms. The disc structure has multiple functional components, and therefore, the artificial disc must completely replace the original diseased tissue [Figure 2]. This will permit the technology to be applied to any stage of disc degeneration if the adjacent tissues are not involved. It can be assumed that the indications for usage of disc arthroplasty will be similar to current interbody arthrodesis techniques. If spine arthroplasty produces clear benefits, similar clinical outcomes, and acceptable risks, it will be an ideal adjunctive device to replace segmental arthrodesis in the management of symptomatic degenerative disc disease.
Figure 1. The advantages of arthroplasty compared to arthrodesis include:
•Immediate pain relief
•Frequency of failed fusion
•Adjacent level degeneration