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[Mid-term effectiveness of Coflex interspinous dynamic internal fixation combined with spinal fusion for lumbar disc degeneration].

Objective
To evaluate the effectiveness of Coflex interspinous dynamic internal fixation combined with spinal fusion for lumbar disc degeneration.


Methods
The clinical data of 39 patients with two-level lumbar disc degeneration who met the selection criteria between June 2010 and December 2011 was retrospectively analyzed. They were divided into group A (20 cases, simple lumbar decompression and fusion) and group B (19 cases, Coflex interspinous dynamic internal fixation combined with spinal fusion) according to different surgical methods. There was no significant difference in age, gender, disease diagnosis, lesion segment, disease duration, Oswestry disability index (ODI), visual analogue scale (VAS) score, and the intervertebral height, foramen intervertebral height (FIH), and range of motion (ROM) of upper operative segment and adjacent segment between the two groups ( P>0.05). ODI and VAS score were used to evaluate the effectiveness before operation and at last follow-up, and the improvement rates were calculated. The intervertebral height [anterior disc height (ADH), middle disc height (MDH), and posterior disc height (PDH)], FIH, and ROM were measured and compared between the two groups.


Results
The operation time and intraoperative blood loss in group A were significantly more than those in group B ( P<0.05), and there was no significant difference in hospitalization time between the two groups ( t=0.992, P=0.328). All patients were followed up; the follow-up time was 33-50 months (mean, 40.5 months) in group A and 39-51 months (mean, 42.6 months) in group B. No complication such as displacement, loosening, or rupture of internal fixator was found in both groups. At last follow-up, ODI and VAS score of the two groups significantly improved when compared with preoperative scores ( P<0.05). At last follow-up, there was no significant difference in ODI, VAS score, and improvement rate of ODI between the two groups ( P>0.05); the improvement rate of VAS score in group B was significantly higher than that in group A ( t=2.245, P=0.031). There was no significant difference in the intervertebral height and FIH of the upper operative segment at last follow-up between the two groups and between preoperation and last follow-up in the two groups ( P>0.05). At last follow-up, the ADH of adjacent segment in group B was significantly higher than that in group A, and MDH, PDH, and FIH were significantly lower than those in group A ( P<0.05). Compared with preoperation, the ADH of adjacent segment in group A decreased and MDH, PDH, and FIH increased at last follow-up ( P<0.05), while all indexes in group B did not change significantly ( P>0.05). The ROM of adjacent segment in group A increased significantly at last follow-up ( t=2.318, P=0.026). There was significant difference in ROM of adjacent segment between the two groups ( P<0.05).


Conclusion
The mid-term effectiveness of Coflex interspinous dynamic internal fixation combined with spinal fusion is similar to that of simple decompression fusion. For those patients whose adjacent segments of the responsible segments have degeneration but have no symptoms or mild symptoms, this treatment can slow down the adjacent segment degeneration.