The intervertebral disc prosthesis meets primary coverage criteria for effectiveness and is covered when implanted at one level, L4-5 or L5-S1 when all of the following criteria are met:

 

Insertion of the artificial lumbar disc at more than one lumbar level is not covered because the safety and effectiveness of the artificial lumbar disc for treatment of more than one level of lumbar disc disease has not been determined, and therefore does not meet member benefit certificated Primary Coverage Criteria.

 

The FDA issued an approval of the Charite Artificial Disc on 10/26/04 (P040660).   

 

Several case series have been published describing the international experience with the SB Charlie device. LeMaitre summarized the results of the largest case series that included 105 patients with a mean follow-up of 51 months.  A total of 79% of patients reported an excellent result, with 87% returning to work. The intended segmental mobility was noted radiologically. Hoohsehtiler and colleagues summarized their experience with the SB Charite III device at the Texas Back Institute.  The series included 56 patients; 22 had 12 months of follow-up. There was significant improvement in pain and function, as measured by a visual analog scale and Oswestry Low Back Pain Disability questionnaire score, respectively.

 

The first report of Class I data comparing the lumbar artificial disc (n=205) to lumbar fusion (n=99) stated neurological status was equivalent  between the two groups at 6, 12, and 24 months.  The number of patients with major, minor, or other neurological complications was equivalent.

 

 

 

  

 

The pivotal study for the Kineflex artificial disc was a randomized controlled trial that compared the Kineflex-L with an artificial disc (Charite) that was already approved for sale (Guyer, 2014). There were 261 patients in the Kineflex group and 196 patients in the Charite group. The primary outcome measure for the published study was a composite success measure at 24 months of at least 15-point improvement in ODI score, no subsequent operative intervention related to the device and no major adverse events. Twenty-four month follow-up was obtained in 94.8% of the Kineflex-L group and 91.3% of the Charite group. There were no significant differences between the Kineflex-L and Charite groups for overall success (76.5% vs 74.7%, respectively) or in the individual components of success. Reoperations were performed in 10.3% of the Kineflex-L group and 8.4% of the Charite group. In the Kineflex group, the 11 reoperations were due to lymphocytic reaction (n=2), device migration (n=2), and supplemental fixation implantations (n=5). In 2011, the authors of this study had published a report of early failure of metal-on-metal disc prostheses in 4 patients due to a lymphocytic reaction, similar to that observed in metal-on-metal hip implants.  A FDA advisory committee meeting on the Kineflex lumbar disc was scheduled for July 2013, but was cancelled without explanation.

 

Siepe et al reported minimum 5-year follow-up 181 patients implanted with the ProDisc II at their institution (Siepe, 2014). This represented 90.0% of the initial cohort of 201 patients from this prospective clinic-funded quality review study. Disc replacement was performed for the treatment of predominant (≥80%) axial low back pain. Radiculopathy was a contraindication, and all patients underwent fluoroscopically guided infiltrations of the facet and and sacroiliac joints to rule out nondiscogenic pain sources. Baseline ODI and VAS pain scores, assessed by investigators who were not involved in pre- or postoperative decision making, were approximately 42 and 7.1, respectively. After a mean of 7.4 years (range 5.0-10.8 years), VAS pain scores remained significantly improved over baseline (mean of 3.3, p<0.0001), although a slight deterioration (0.66 on a scale of 10) was observed between 48 and 120 months (p<.05). ODI scores remained stable throughout follow-up, with a final score of approximately 22 (p<0.001). The complication rate for single level disc replacement was 11.9% compared with 27.6% for bi-segmental disc replacement (p=0.031). The overall satisfaction rate was 89.1% for single level and 69.0% for two-level disc replacement.

 

Five-year results of lumbar disc arthroplasty from the Swiss Spine Registry were published in 2014 (Aghayev, 2014). Five devices were used during the period of study (Activ L, Charite, Dynardi, Maverick, and ProDisc-L). Out of 248 patients who were eligible for the 5-year study, follow-up was obtained from 77% of patients at 1 year, 44% at 2 years, and 51.2% at 5 years. In the 127 patients with follow-up through 5 years, there was a significant reduction of VAS back pain (from 73 to 29) and leg pain (from 55 to 22). Note that the presence of radiculopathy does not appear to have been an exclusion for disc arthroplasty at these institutions. The overall complication rate at 5 years was 23.4% which included a new radiculopathy in 10.5% of patients, the rate of adjacent segment degeneration was 10.7%, and 43.9% of patients had osteophytes that could potentially affect the range of motion. The cumulative probability of survivorship at 5 years was calculated to be 90.4%.

 

 

 

Two-year outcomes from the multicenter IDE trial of the activL artificial intervertebral disc were reported by Garcia and colleagues (Garcia, 2015). In this patient-blinded noninferiority trial, patients with DDD at L4-L5 or L5-S1 were randomized to treatment with activL (n=218) or an FDA-approved disc (n=106; ProDisc-L or Charité). Based on the primary composite end point (a ≥15 point improvement on ODI score, maintenance or improvement in neurologic status, maintenance or improvement in range of motion at the index level, freedom from additional surgery at the index level, freedom from serious device-related adverse events), activL was both noninferior (p<0.001) and superior (p=0.02) to the control group. Intention-to-treat analysis of secondary outcome measures showed similar improvements between activL and controls in back pain (74% vs 68%), ODI scores (75.2% vs 66.0%), device success (84.4% vs 84.9%), surgical reintervention (2.3% vs 1.9%), and patient satisfaction scores for the 2 groups (94.1% vs 93.1%), all respectively. Radiographic success, defined as maintenance or improvement in range of motion at the index level as measured by an independent core radiographic laboratory, was higher in the activL group than in the ProDisc-L and Charité controls (59% vs 43%, p<0.01).

 

 

In 2015, Lu and colleagues reported minimum 11-year follow-up on 32 of 35 patients implanted with the Charité III (Lu, 2015). Of the 3 patients not included in this prospective study, 1 chose not to participate, 1 was lost to follow-up, and 1 died of unrelated causes. Prior to surgery, VAS score for back pain was 8.5 and ODI score was 41.4; the mean duration of symptoms was 5.4 years. At an average of 11.8 years after device implantation (range, 11.3-13.8 years), VAS score improved to 1.5 (p=0.0015), ODI score improved to 13.2 (p=0.0047), and 87.5% had a successful outcome based on FDA criteria. There were no device failures or major complications (1 patient developed severe leg pain associated with adjacent segment degeneration and had spinal decompression). Heterotopic ossification was observed in 71.4% of segments, but was associated with a decrease in range of motion in only 25.7% of segments. The authors proposed several reasons for the high success rate in this group, including strict selection criteria and the lighter body weight of most Chinese compared to Western patients (eg, less load on the prosthesis).

 

In 2015, Hoff and colleageus published an RCT with 62 patients that compared a hybrid procedure (anterior lumbar interbody fusion at 1 level and a Maverick disc at another level) to 2-level circumferential fusion (Hoff, 2015). VAS score for pain was significantly lower by about 1 point on a 10-cm scale in the hybrid group compared to the 2-level fusion group both postoperatively and at 3-year follow-up. There was no significant difference between groups in ODI scores. ASD did not differ significantly between groups.

 

 

 

 

 

review was determined to be a 2012 Cochrane review with an AMSTAR rating of 9.5 Cochrane reviewers concluded that, although there were statistically significant improvements in clinical outcomes of disability, pain relief, and quality of life with TDR for DDD in the short term, the differences were not  clinically significant. In addition, prevention of adjacent segment and facet joint degeneration had not been adequately evaluated. Given the uncertainty of risks and benefits in the long-term, caution was advised. A limitation of the 2012 Cochrane review is that many of the selected studies used a Charité disc, which is no longer marketed in the United States.