The Spine Journal. Volume 9, Issue 5, May 2009, Pages 374-386

Clinical Study

Prospective, randomized, multicenter Food and Drug Administration investigational device exemption study of lumbar total disc replacement with the CHARITÉ artificial disc versus lumbar fusion: Five-year follow-up

Richard D. Guyer MDa, Paul C. McAfee MDb, Robert J. Banco MDc, Fabian D. Bitan MDd, Andrew Cappuccino MDe, Fred H. Geisler MD PhDf, Stephen H. Hochschuler MDa, Richard T. Holt MDg, Louis G. Jenis MDc, Mohamed E. Majd MDg, John J. Regan MDh, Scott G. Tromanhauser MDc, Douglas C. Wong MDi and Scott L. Blumenthal MDa

aTexas Back Institute, 6020 West Parker Road, Suite 200, Plano, TX 75093, USA. bSpine and Scoliosis Center, 7505 Osler Drive, Suite 104, Towson, MD 21204, USA. cBoston Spine Group, 125 Parker Hill Avenue, Boston, MA 02120, USA. dLennox Hill Hospital, 130 East 77th Street, 7th Floor, New York, NY 10003, USA. eBuffalo Spine Surgery, 46 Davison Street, Lockport, NY 14094, USA. fIllinois Neuro-Spine Center, 2020 Ogden Avenue, Suite 335, Aurora, IL 60504, USA. gSpine Surgery, PSC, 210 East Gray Street, Suite 601, Louisville, KY 40202, USA. hG&P Orthopedic Associates, 120 South Spalding Drive, Suite 400, Beverly Hills, CA 90212, USA. iPanorama Orthopedics, 660 Golden Ridge Road, Suite 250, Golden, CO 80401, USA. Received 9 April 2008; accepted 5 August 2008. Available online 19 September 2008.


Background context

The CHARITÉ 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 CHARITÉ disc or any other artificial disc has been published to date.

Purpose

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 CHARITÉ 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.

Study design/setting

Randomized controlled trial—five-year follow-up.

Patient sample

Ninety CHARITÉ patients and 43 BAK patients.

Outcome measures

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.

Methods

Of the 375 subjects enrolled in the CHARITÉ 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≥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.

Results

Overall success was 57.8% in the CHARITÉ group vs. 51.2% in the BAK group (Blackwelder's test: p=0.0359, Δ=0.10). In addition, mean changes from baseline for ODI (CHARITÉ: −24.0 pts vs. BAK: −27.5 pts), VAS pain scores (CHARITÉ: −38.7 vs. BAK: −40.0), and SF-36 questionnaires (SF-36 Physical Component Scores [PCS]: CHARITÉ: 12.6 pts vs. BAK: 12.3 pts) were similar across groups. In patient satisfaction surveys, 78% of CHARITÉ patients were satisfied vs. 72% of BAK patients. A total of 65.6% patients in the CHARITÉ 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 CHARITÉ 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 CHARITÉ 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° for CHARITÉ patients and 1.0° for BAK patients. Changes in disc height were also similar for both CHARITÉ and BAK patients (0.7 mm for both groups, p=0.9827). Segmental translation was 0.4 and 0.8 mm in patients implanted with CHARITÉ at L4–L5 vs. L5–S1, respectively, and 0.1 mm in BAK patients.

Conclusions

The results of this five-year, prospective, randomized multicenter study are consistent with the two-year reports of noninferiority of CHARITÉ artificial disc vs. ALIF with BAK and iliac crest autograft. No statistical differences were found in clinical outcomes between groups. In addition, CHARITÉ 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.

Copyright © 2009 Elsevier Inc. All rights reserved