Article Figures & Data
Figures
- Fig. 1
Viscoelastic total disc replacement.
- Fig. 2
Mean ODI and VAS low back pain scores.
- Fig. 3
Median ODI and VAS low back pain scores.
- Fig. 4
Exemplar radiographs of a study patient.
Tables
Assessment Preoperatively Discharge 6 wk 3 mo 6 mo 1 y 2 y Range −6 mo ± 2 wk ± 2 wk ± 2 wk ± 1 mo ± 2 mo ± 2 mo Inclusion criteria Exclusion criteria Symptomatic degenerative disc unresponsive to nonoperative management for a minimum of 6 mo with imaging studies (eg, radiography, CT, and MRI) verifying L4-L5 or L5-S1 structural abnormalities (eg, disc space collapse, grade 1 degenerative spondylolisthesis, desiccated disc, annular tears, or endplate morphologic changes) Abnormal pain profile as suggested by 1 or more of the following: nonanatomic pain diagram, ODI >80, and surgeon assessment Aged 20–60 y (inclusive) ODI <30 Mentally, emotionally, and physically able to understand the procedure; to comply with postoperative care instructions; and to adhere to 2-y follow-up schedule Provocative discography with non-concordant pain at the operative level Sagittal translation >5 mm at the operative level or above Symptoms associated with >1 lumbar level Evidence of grade 2 degenerative spondylolisthesis or greater, any isthmic spondylolisthesis, or arachnoiditis Radiographic findings of end-stage disc resorption and collapse, prior fracture of lower lumbar spine (eg, endplate sclerosis, endplate irregularities, bone-on-bone collapse, or peripheral rim osteophytes), or degenerative collapse of >3 levels, which—in the opinion of the investigator—prevents the patient from participating in the study Congenital or acquired structural defect (eg, scoliosis) at the operative level or above Acute disc herniation with radiculopathy Clinically significant facet arthrosis or other posterior element lysis or loss at the operative level Significant leg pain of a radicular or neurogenic claudication nature Spinal stenosis Symptoms associated with any neurologic signs Prior fusion at any lumbar level or laminectomy or discectomy at the operative level History of any invasive malignancy (except nonmelanoma skin cancer) unless treated with curative intent and there had been no clinical signs or symptoms or malignancy for at least 5 y Prior radiation to the spine Systemic disease affecting the spine, including rheumatoid arthritis, autoimmune disease, AIDS, HIV, and hepatitis Acute or chronic infection (local or systemic) Using medications or drugs known to potentially interfere with bone or soft-tissue healing (eg, steroids) Primary osteoporosis or osteopenia (DEXA T score <1.0) or metabolic bone disease Overweight as indicated by a body mass index ≥30 Pregnant or interested in becoming pregnant in the next 3 y Known or suspected allergy to titanium, polyethylene, cobalt, chromium, or molybdenum Evidence of drug or alcohol abuse Participation in another clinical trial within 8 wk of the baseline visit and for the duration of this trial Diabetic patients and patients with a history of implant rejection Abbreviations: CT, computed tomography; DEXA, dual-energy x-ray absorptiometry; HIV, human immunodeficiency virus; MRI, magnetic resonance imaging.
Variable Result (N = 50) Mean age (y) 39.7 ± 8.3 Gender Female 22 (44.0%) Male 28 (56.0%) Weight (kg) 75.0 ± 12.3 Height (m) 1.7 ± 0.09 Mean body mass index (kg/m2) 25.3 ± 3.0 Race Asian 1 (2%) White 49 (98%) Significant systemic/concurrent disease 10 (20%) Prior lumbar procedures 1 (2%) Smoking history None or none in past 10 y 27 (54%) In past 10 y but none currently 7 (14%) Currently <1 pack/day 12 (24%) Currently >1 pack/day 4 (8%) Work status Not working 22 (44%) Working full time 21 (42%) Working part time 4 (8%) Not applicable* 3 (6%) Currently receiving disability benefits No 30 (60%) Yes, back only 20 (40%) Yes, other than back 0 (0.0%) Yes, back and other reasons 0 (0.0%) Workers’ compensation in past year† Yes 6 (12%) No 44 (88%) Duration of back pain history Mean (mo) 85.8 ± 61.0 Median (mo) 60 Variable Result (N = 50) Index level implanted L4-L5 13 (26%) L5-S1 37 (74%) Operative time: skin to skin (min) Mean 127.6 ± 33.0 Median 120 Mean estimated blood loss (mL) Mean 206.4 ± 259.0 Median 150 Mean hospital length of stay (d) Mean 5.1 ± 1.7 Median 5 Interval 6 mo 12 mo 24 mo Question 1: Would you choose to have the same treatment for your back condition? Definitely yes 68% 71.4% 66.7% Probably yes 20% 14.3% 12.8% Not sure 12% 10.2% 15.4% Probably not or definitely not 0% 4.1% 5.1% Question 2: Would you recommend this procedure to a family member or friend with the same back condition? Definitely yes 63% 69.4% 71.8% Probably yes 29% 16.3% 7.7% Not sure 8% 12.2% 12.8% Probably not or definitely not 0% 2% 7.7% 6 mo 12 mo 24 mo Worse from baseline (95% confidence interval) 2.1% (0.1%–11.3%) 4.4% (0.5%–15.2%) 7.1% (1.5%–19.5%) No change or improved from baseline (95% confidence interval) 97.9% (88.7%–100.0%) 95.6% (84.9%–99.5%) 92.9% (80.5%–98.5%) Osteophyte rating Mean ROM Preoperatively 6 mo 12 mo 24 mo None 8.6° 5.3° 4.2° 4.7° Mild 7.9° 5.3° 4.5° 4.8° Moderate 5.9° 3.9° 3.6° 4.1° Severe 12.2° 5.4° 2.9° 3.9°
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