DIAM device for low back pain in degenerative disc disease : 24 months follow-up.

Purpose: To evaluate the usefulness of the DIAM device in patients affected by low back pain due to degenerative disc disease.

Background: Recently a number of interspinous devices for dynamic interspinous distraction-stabilization have entered the clinical practice in Europe. All of these devices have a common property of acting on the posterior part of the functional spinal unit by distracting the spinous processes and avoiding extension of the treated segment. Consequently, these systems seem to improve the cross-sectional area of the thecal sac and enlarge the diameter of the intervertebral foramina. What was found as a collateral observation after implantation of these devices was that those patients affected by low back pain, improved significantly in their pain level.

Methods And Materials: Fifty-two consecutive patients were included in the study. There were 29 females and 23 males, aged between 29 and 77 years (mean 49.4 ± s.d. 12.4). The pre-operative symptom duration ranged from 6 to 84 months (mean 31.8 ± s.d. 20.2, median 24 months).The following diagnostic measures were performed in each patient: MRI, dynamic X-rays and provocative discography positive for pain reproduction.The patients were followed for pain by VAS and for functional status by self-reported Roland-Morris Disability Questionnaire. The minimum follow-up was 24 months (24-36). The intermediate follow-up at 6, 12 and 18 months was tested for, too.

Results: To determine the number of improved patients we have arbitrarily selected a cut-off criteria based on a ≥30% of improvement as calculated on the Roland Morris Disability Questionnaire scale comparing the 24 months values to the baseline values. Forty-six patients (88%) were considered as success and 2 (4%) were considered as failure. No long-term complications were observed.

Conclusions: This preliminary report indicates that the DIAM device could possibly be useful in the treatment of LBP due to DDD. Further research with RCT is necessary to confirm these preliminary results.