A new ceramic interspinous process spacer for lumbar spinal canal stenosis.

OBJECTIVE

Because surgery in elderly patients should be minimally invasive, interspinous process distraction has been widely used in this group to treat lumbar canal stenosis. We developed a new interspinous process distraction spacer composed of hydroxyapatite ceramic. In this work, we demonstrate the usefulness of this novel device.

METHODS

Since 2003, we operated on 19 elderly patients with lumbar canal stenosis, including 14 men and five women. Their mean age was 70.1 years. We compared the intervertebral angle, posterior disc height, and interspinous process distance on midsagittal magnetic resonance images obtained before and after the surgery. We also assessed clinical outcomes by using the Visual Analog Scale and the Zurich Claudication Questionnaire.

RESULTS

The average operation time per level was 44.7 minutes. Postoperatively, there were significant changes in the angle (from 12.5 to 8.6 degrees, P < 0.0001), the posterior disc height (from 10.6 to 13.1 mm, P < 0.0001), and the interspinous process distance (from 9.7 to 14.1 mm, P < 0.0001). The clinical outcomes, which we assessed by using the Visual Analog Scale and the Zurich Claudication Questionnaire, were considered satisfactory. (Visual Analog Scale, from 6.88 to 3.00; Zurich Claudication Questionnaire, symptom severity domain from 2.94 to 1.92, physical function from 2.51 to 1.73.)

CONCLUSION

Our ceramic spacer is useful in the treatment of elderly patients with lumbar canal stenosis. Treatment comprises an easy surgical procedure and produces no metal artifact on radiological evaluations, such as magnetic resonance imaging and computed tomographic scans.