Why Lumbar Artificial Disk Replacements (LADRs) Fail

Management Considerations for Total Intervertebral Disc Replacement

The burden of disease regarding lumbar and cervical spine pain is a long-standing, pervasive problem within medicine that has yet to be resolved. Specifically, neck and back pain are associated with chronic pain, disability, and exorbitant health care use worldwide, which have only been exacerbated by the increase in overall life years and chronic disease. Traditionally, patients with significant pain and disability secondary to disease of either the cervical or lumbar spine are treated via fusion or discectomy. Although these interventions have proved curative in the short-term, numerous longitudinal studies evaluating the efficacy of traditional management have reported severe impairment of normal spinal range of motion, as well as postoperative complications, including neurologic injury, radiculopathy, osteolysis, subsidence, and infection, paired with less than desirable reoperation rates. Consequently, there is a call for innovation and improvement in the treatment of lumbar and cervical spine pain, which may be answered by a modern technique known as intervertebral disc arthroplasty, or total disc replacement (TDR). Thus, this review aims to describe the management strategy of TDR and to explore updated considerations for its use in practice, both to help guide clinical decision making.

Barriers to and Budget Impact of Lumbar Total Disc Replacement Utilization

: Evidence on the favorable efficacy, safety, and cost effectiveness of lumbar total disc replacement (TDR) compared with fusion for lumbar degenerative disc disease is mounting; however, a key barrier identified for TDR utilization is lack of coverage by US health insurers. Although economic considerations in a fee-for-service model should not be a determining factor in patient access, concerns regarding the budget impact of lumbar TDR surgery may unfortunately underlie coverage decisions. On the basis of the data available and economic modeling, the panel agreed that there is no indication that there would be a dramatic increase in patients seeking lumbar TDR. Considering several possible scenarios on potential growth in TDR utilization with coverage, as well as growth in the overall surgical pool of patients, economic modeling demonstrated that adoption of lumbar TDR would result in minimal or no budget impact for commercial insurance plans. Considering these model results and the economic literature, the panel concluded that adopting lumbar TDR within a coverage policy is expected to remain cost neutral for the insurer.

Defining the Ideal Lumbar Total Disc Replacement Patient and Standard of Care

: Lumbar total disc replacement, now in use since 2004, was determined by the panel to be a standard of care for the treatment of symptomatic single-level lumbar degenerative disc disease in the active patient subpopulation as outlined by the investigational device exemption study criteria. The large body of evidence supporting this statement, including surgeons' experiences, was presented and discussed. Consensus statements focusing on decision-making criteria reflected that efficacy, long-term safety, clinical outcomes with validated measures, and cost-effectiveness should form the basis of decision-making by payers. Diagnostic challenges with lumbar degenerative disc disease patients were discussed among the panel, and it was concluded that although variably used among surgeons, reliable tools exist to appropriately diagnose discogenic back pain.

Challenges and Solutions for Lumbar Total Disc Replacement Implantation

: Long-term data are now available to support the safety and efficacy of lumbar total disc replacement (TDR). Five-year randomized and controlled trials, meta-analyses, and observational studies support a similar or lower risk of complications with lumbar TDR compared with fusion. The panel concluded that published data on commercially available lumbar TDR devices demonstrate minimal concerns with late-onset complications, and that the risk of adjacent segment degeneration and reoperations can be reduced with lumbar TDR versus fusion. Survey results of surgeon practice experiences supported the evidence, revealing a low rate of complications with TDR. Panelists acknowledged the importance of adhering to selection criteria to help minimize patient complications.

Anterior Longitudinal Ligament Reconstruction to Reduce Hypermobility of Cervical and Lumbar Disc Arthroplasty

Study Design

Retrospective case series

Purpose

This study aims to present the early clinical and radiological outcomes of anterior longitudinal ligament (ALL) reconstruction following disc arthroplasty.

Overview of Literature

Although cervical and lumbar disc arthroplasty have entered the clinical setting, there are still concerns regarding the short and long term complications arising from hypermobility of current prosthesis designs. Reconstruction of the ALL is a potential solution to disc arthroplasty hypermobility.

Methods

ALL reconstruction following disc arthroplasty have been performed by the senior author over a 24 month period. Ligament replacements used include allograft and synthetic, ligament advanced reinforcement system (LARS) ligaments. Methods of fixation used include titanium staples, bone anchors and suture fixation. Radiological follow-up pre- and postoperative Oswestry disability index, Neck Disability Index, Patient Satisfaction index scores were recorded on all patients.

Results

A total of 18 ALL reconstructions were performed. There have been no cases of early complications, revision surgery for recurrent symptoms or implant failure. Of the 6 patients receiving a minimum of 15 months follow-up, 4 patients received an allograft, 2 patients received the LARS ligament. Favourable, postoperative clinical and radiographic outcomes have been demonstrated.

Conclusions

ALL reconstruction following cervical and lumbar disc arthroplasty is a promising solution to addressing non-physiological kinematics of current disc arthroplasty devices. Randomized, controlled studies with larger study samples and long-term follow-up are required to establish these conclusions.

Operative Management of Lumbar Degenerative Disc Disease

Lumbar degenerative disc disease is extremely common. Current evidence supports surgery in carefully selected patients who have failed non-operative treatment and do not exhibit any substantial psychosocial overlay. Fusion surgery employing the correct grafting and stabilization techniques has long-term results demonstrating successful clinical outcomes. However, the best approach for fusion remains debatable. There is some evidence supporting the more complex, technically demanding and higher risk interbody fusion techniques for the younger, active patients or patients with a higher risk of non-union. Lumbar disc arthroplasty and hybrid techniques are still relatively novel procedures despite promising short-term and mid-term outcomes. Long-term studies demonstrating superiority over fusion are required before these techniques may be recommended to replace fusion as the gold standard. Novel stem cell approaches combined with tissue engineering therapies continue to be developed in expectation of improving clinical outcomes. Results with appropriate follow-up are not yet available to indicate if such techniques are safe, cost-effective and reliable in the long-term.