SB Charité Disk Replacement. A Prospective Randomized Study of 60 Consecutive Patients

• (a - Waldemar Link)

Purpose of Study: The lumbar artificial disc is an alternative to arthrodesis. Its purpose is to restore the basic motion of the intervertebral segment and to protect the adjacent levels against unphysiologic loading.

Materials and Methods: Indications for the clinical application of the SB Charité artificial disc replacement in this study were one lumbar level of symptomatic degenerative disc disease (DDD), or lumbar spondylosis with objective evidence of DDD by CT or MRI. Some specific radiographic findings included vacuum disk sign, high intensity zone signal, Modic changes, degenerative cyst formation, and marginal vertebral body osteophyte formation.All patients were studied with a provocative discogram performed by an independent radiologist or anesthesiologist who was not part of the surgical team. Degenerative disc disease was defined as discogenic back pain with degeneration of the disc as confirmed by history and radiographic studies with one or more of the following factors-contained herniated nucleus pulposus; paucity of facet joint degeneration changes; decrease of intervertebral disc height of at least 4mm; or thickening of annulus fibrosis with osteophytes indicating osteoarthritis.

Results: Sixty patients with one level discogenic pain confirmed by plain radiography, MRI, and provocative diskography for degenerative disk disease were randomized 1/3 BAK anterior interbody fusion and 2/3 anterior SB Charité artificial disk replacement. The mean age was 40.3 years (range 21 to 56 years). Nineteen cases were at L4-L5 and 41 cases were L5-S1. Nineteeen cases had BAK anterior interbody fusion and forty -one cases were randomized as SB Charité disk replacement. The length of surgery was mean 88.4 minutes (range 54 to 137 minutes) for both groups. The estimated blood loss was mean 289.5 cc (range 50 to 1800cc). The length of hospital stay was a mean of 3.03 days (range 2 to 6 days). The mean follow up was 24 months (range 15 to 36 months). Oswestry Disability Index for the SB Charité disk were 50.0 +/- 14.3 preoperatively and 25.0 +/- 20.1 at follow up (p <0 .001). Visual Analog Scale functional outcome measurements showed similar improvement. The SB Charité group was 73.5 +/- 14.9 preoperatively and improved to 30.4 29.4 postoperatively (p< 0.001).

Overall Significance of Findings: This is the first study that shows improvement of functional outcome measures in a prospective randomized design treating primarily mechanical back pain and achieving comparable successful results to lumbar spinal stenosis decompression (Bridwell et al: Lumbar Spinal Stenosis. JBJS 84-A: 1954-1959, 2002).

• If noted, the author indicates something of value received. The codes are identified as: a-research or institutional support; b-miscellaneous funding; c-stock or stock options; d-royalties; e-other financial or material support.