Article

Prospective, randomized, multicenter Food and Drug Administration investigational device exemption study of lumbar total disc replacement with the CHARITE artificial disc versus lumbar fusion: five-year follow-up. Spine J 9:374-386

Texas Back Institute, 6020 West Parker Road, Suite 200, Plano, TX 75093, USA.
The spine journal: official journal of the North American Spine Society (Impact Factor: 2.43). 09/2009; 9(5):374-86. DOI: 10.1016/j.spinee.2008.08.007
Source: PubMed

ABSTRACT

The CHARITE artificial disc, a lumbar spinal arthroplasty device, was approved by the United States Food and Drug Administration in 2004 based on two-year safety and effectiveness data from a multicenter, prospective, randomized investigational device exemption (IDE) study. No long-term, randomized, prospective study on the CHARITE disc or any other artificial disc has been published to date.
The purpose of this study was to compare the safety and effectiveness at the five-year follow-up time point of lumbar total disc replacement using the CHARITE artificial disc (DePuy Spine, Raynham, MA) with that of anterior lumbar interbody fusion (ALIF) with BAK cages and iliac crest autograft, for the treatment of single-level degenerative disc disease from L4 to S1, unresponsive to nonoperative treatment.
Randomized controlled trial-five-year follow-up.
Ninety CHARITE patients and 43 BAK patients.
Self-reported measures: visual analog scale (VAS); validated Oswestry disability index (ODI version 1.0); Short-Form 36 Questionnaire, and patient satisfaction. Physiologic measures: radiographic range of motion, disc height, and segmental translation. Functional measures: work status.
Of the 375 subjects enrolled in the CHARITE IDE trial, 277 were eligible for the five-year study and 160 patients thereof completed the five-year follow-up. The completers included 133 randomized patients. Overall success was defined as improvement> or =15 pts in ODI vs. baseline, no device failure, absence of major complications, and maintenance or improvement of neurological status. Additional clinical outcomes included an ODI questionnaire as well as VAS, SF-36, and patient satisfaction surveys. Work status was tracked for all patients. Safety assessments included occurrence and severity of adverse events and device failures. Radiographic analyses such as index- and adjacent-level range of motion, segmental translation, disc height, and longitudinal ossification were also carried out.
Overall success was 57.8% in the CHARITE group vs. 51.2% in the BAK group (Blackwelder's test: p=0.0359, Delta=0.10). In addition, mean changes from baseline for ODI (CHARITE: -24.0 pts vs. BAK: -27.5 pts), VAS pain scores (CHARITE: -38.7 vs. BAK: -40.0), and SF-36 questionnaires (SF-36 Physical Component Scores [PCS]: CHARITE: 12.6 pts vs. BAK: 12.3 pts) were similar across groups. In patient satisfaction surveys, 78% of CHARITE patients were satisfied vs. 72% of BAK patients. A total of 65.6% patients in the CHARITE group vs. 46.5% patients in the BAK group were employed full-time. This difference was statistically significant (p=0.0403). Long-term disability was recorded for 8.0% of CHARITE patients and 20.9% of BAK patients, a difference that was also statistically significant (p=0.0441). Additional index-level surgery was performed in 7.7% of CHARITE patients and 16.3% of BAK patients. Radiographic findings included operative and adjacent-level range of motion (ROM), intervertebral disc height and segmental translation. At the five-year follow-up, the mean ROM at the index level was 6.0 degrees for CHARITE patients and 1.0 degrees for BAK patients. Changes in disc height were also similar for both CHARITE and BAK patients (0.7 mm for both groups, p=0.9827). Segmental translation was 0.4 and 0.8mm in patients implanted with CHARITE at L4-L5 vs. L5-S1, respectively, and 0.1mm in BAK patients.
The results of this five-year, prospective, randomized multicenter study are consistent with the two-year reports of noninferiority of CHARITE artificial disc vs. ALIF with BAK and iliac crest autograft. No statistical differences were found in clinical outcomes between groups. In addition, CHARITE patients reached a statistically greater rate of part- and full-time employment and a statistically lower rate of long-term disability, compared with BAK patients. Radiographically, the ROMs at index- and adjacent levels were not statistically different from those observed at two-years postsurgery.

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    • "To avoid these negative side effects, motion-preserving technologies, such as lumbar total disc replacement (TDR), have been introduced as alternatives to spinal fusion. Several clinical studies have demonstrated satisfactory clinical results for monosegmental TDR, but these results were demonstrated only in carefully selected patients (Freeman and Davenport, 2006;Guyer et al., 2009;Siepe et al., 2014). Various contraindications have been identified for TDR (Chin, 2007;Huang et al., 2004;McAfee, 2004;Wong et al., 2007), and the success of TDR in the clinic has fallen short of its initial high expectations. "
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    ABSTRACT: Total disc replacement has been introduced to overcome negative side effects of spinal fusion. The amount of iatrogenic distraction, preoperative disc height and implant positioning have been considered important for surgical success. However, their effect on the postoperative range of motion (RoM) and loading of the facets merits further discussion. A validated osteoligamentous finite element model of the lumbosacral spine was employed and extended with four additional models to account for different disc heights. An artificial disc with a fixed center of rotation (CoR) was implemented in L5-S1. In 4,000 simulations, the influence of distraction and the CoR’s location on the RoM, facet joint forces (FJFs) and facet capsule ligament forces (FCLFs) was investigated. Distraction substantially altered segmental kinematics in the sagittal plane by decreasing range of flexion (0.5° per 1mm of distraction), increasing range of extension (0.7°/mm) and slightly affecting complete sagittal RoM (0.2°/mm). The distraction already strongly increased the FCLFs during surgery (up to 230N) and in flexion (~12N/mm), with higher values in models with larger preoperative disc heights, and increased FJFs in extension. A more anterior implant location decreased the RoM in all planes. In most loading cases, a more posterior location of the implant’s CoR increased the FJFs and FCLFs, whereas a more caudal location increased the FCLFs but decreased the FJFs. The results of this study may explain the worse clinical results in patients with overdistraction after TDR. The complete RoM in the sagittal plane appears to be insensitive to detecting surgery-related biomechanical changes.
    No preview · Article · Jul 2015 · Journal of Biomechanics
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    • "The current literature reported only long-term follow-up of TDR. Both medium-term follow-up (from five to ten years) [27–30] and long-term follow-up (>10 years) [31, 32] showed significant improvement postoperatively in clinical, and in radiological the motion preserved in surgical segment, lower rate of adjacent segment degeneration. No special complications were noted. "
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    ABSTRACT: Purpose To compare the efficacy and safety of TDR to that of the fusion for the treatment of lumbar degenerative disc disease (LDDD). Methods Randomized controlled trials comparing TDR with any other intervention for LDDD were acquired by a comprehensive search in PubMedCentral, MEDLINE, EMBASE, BIOSIS, ClinicalTrials.gov, and the FDA trials register. Methodologic quality was assessed and relevant data were retrieved, and appropriate meta-analysis was performed. Two review authors independently selected studies, extracted data, and assessed risk of bias. Results and upper bounds of confidence intervals were compared with predefined clinically relevant differences. Results Six relevant randomized controlled trials (RCTs) involving 1,603 patients were identified and reported two year follow-up results. Patients in TDR group compared with lumbar fusion group demonstrated significant improvements in ODI, VAS scores and complication rates at the two year follow-up. Meanwhile, except for operating time in anterior group, intra-operative blood loss, operating time in posterior group, and reoperation rate were without clinical significance between the two groups. In addition, the range of motion (ROM) was maintained within normal ranges after TDR. Conclusions The results showed the TDR has significant safety and efficacy comparable to lumbar fusion at two year follow-up. Although superiority compared to fusion could not be proved, by comparing clinical symptoms relieved, motion preserved, and the low reoperation rate during long-term follow-up on TDR, TDR was considered safe and effective. Therefore, the authors suggest adopting TDR on a large scale; with failure of TDR, interbody fusion would be performed.
    Full-text · Article · May 2013 · International Orthopaedics
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    • "At this point, the effects of the bending stiffness of motion preserving devices on affected and adjacent segments are not completely understood. The long-term clinical effects of motion preserving spine surgery on adjacent levels are being investigated although long-term data is not yet available[29], [30], [31]. "
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    ABSTRACT: Biomechanical investigations of spinal motion preserving implants help in the understanding of their behavior. In this study, we hypothesized that the lumbar spine with implanted total spinal segment replacement (TSSR) would exhibit decreased dynamic stiffness and more rapid energy absorption compared to native functional spinal units under simulated physiologic motion when tested with the pendulum system. Five unembalmed, frozen human lumbar functional spinal units were tested on the pendulum system with axial compressive loads of 181 N, 282 N, 385 N, and 488 N before and after Flexuspine total spinal segment replacement implantation. Testing in flexion, extension, and lateral bending began by rotating the pendulum to 5°; resulting in unconstrained oscillatory motion. The number of rotations to equilibrium was recorded and bending stiffness (N-m/°) was calculated and compared for each testing mode. The total spinal segment replacement reached equilibrium with significantly fewer cycles to equilibrium compared to the intact functional spinal unit at all loads in flexion (p<0.011), and at loads of 385 N and 488 N in lateral bending (p<0.020). Mean bending stiffness in flexion, extension, and lateral bending increased with increasing load for both the intact functional spinal unit and total spinal segment replacement constructs (p<0.001), with no significant differences in stiffness between the intact functional spinal unit and total spinal segment replacement in any of the test modes (p>0.18). Lumbar functional spinal units with implanted total spinal segment replacement were found to have similar dynamic bending stiffness, but absorbed energy at a more rapid rate than intact functional spinal units during cyclic loading with an unconstrained pendulum system. Although the effects on clinical performance of motion preserving devices is not fully known, these results provide further insight into the biomechanical behavior of this device under approximated physiologic loading conditions.
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