Cervical and lumbar spinal arthroplasty: clinical review

Abstract

In contrast to cervical and lumbar fusion procedures, the principal aim of disk arthroplasty is to recapitulate the normal kinematics and biomechanics of the spinal segment affected. Following decompression of the neural elements, disk arthroplasty allows restoration of disk height and maintenance of spinal alignment. Based on clinical observations and biomechanical testing, the anticipated advantage of arthroplasty over standard arthrodesis techniques has been a proposed reduction in the development of symptomatic ALD. In this review of cervical and lumbar disk arthroplasty, we highlight the clinical results and experience with standard fusion techniques, incidence of ALD in the population of patients with surgical fusion, and indications for arthroplasty, as well as the biomechanical and clinical outcomes following arthroplasty. In addition, we introduce the devices currently available and provide a critical appraisal of the clinical evidence regarding arthroplasty procedures.

Fig 1.

Ideal candidate for cervical arthroplasty. A, Lateral radiograph depicting minimal facet arthropathy and degenerative disease. B and C, Extension (B) and flexion (C) radiographs depicting normal segmental motion at the index level and throughout the cervical spine. D, Sagittal T2-weighted MR image depicting single-level degenerative disk disease, endplate changes, relative preservation of disk height, and posterior disk bulge without marked osteophyte formation.

Fig 2.

Case illustrating the importance of patient positioning for optimized biomechanics. A, A 36-year-old man with radicular symptoms referable to this C6–7 paramedian disk herniation seen on a sagittal T2-weighted MR image. The patient was positioned in mild cervical lordosis during ProDisc-C placement. B and C, As a result, postoperative extension (B) and flexion (C) radiographs obtained at 6 months revealed no movement at the instrumented level. D, Segmental motion was evident only with maximal extension beyond the typical physiologic range of motion.

Fig 3.

Dynamic flexion (A) and extension (B) postoperative lateral cervical radiographs following Prestige-ST arthroplasty in a 56-year-old woman. Segmental range of motion is preserved by the Prestige-ST device. Despite motion preservation, this particular patient ultimately required CT myelography, removal of the arthroplasty device, and 2-level anterior cervical fusion for symptomatic adjacent-level disease 1 year after arthroplasty.

Fig 4.

Case illustrating the importance of device positioning. A 37-year-old man with prior history of noninstrumented L5-S1 microdiskectomy, now presenting with axial back pain. A, Sagittal T2-weighted MR image depicting degenerative disk disease at the previously operated level. Normal segmental motion without radiographically detectable instability was identified on preoperative flexion/extension dynamic radiographs. B and C, Postoperative lateral (B) and anteroposterior (C) views depicting the off-midline position of the ProDisc-L device. At the time of device placement, visualization of the L5-S1 level was limited due to immobile vascular structures. D, The patient awoke with right S1 radicular pain attributable to foraminal encroachment from the device as seen on this axial CT scan. The patient failed a short course of conservative management and ultimately required a right-sided L5-S1 hemilaminotomy, foraminotomy, and partial facetectomy for relief of symptoms.