Retrospective Study Of Adjacent Segment Degeneration Of The Upper Level To A Lumbar Fusion With And Without Instrumentation

As the development of spinal fusion and instrumentation, the rates of fusion are remarkable highly.However, ASD has become a serious problem after fusion.Disc degeneration grading on MRI was based on a modified Pfirrmann grade by observing the T2-weighted image at the midsagittal plane; degenerated disc was defined as intervertebral disc that showed significantly low signal intensity and a loose border between the nucleus pulposus and anulus fibrosus.Some authors use plain radiograph for diagnotic accuracy of ASD,but made lots of contradictory results.We collect 56cases of in patients which have been treated and follow-up 3years during 2008.1-2011.2.At follow-up,2 patients could not be located,1 were deceased,4 patients unfusion,3 patients without MRI,and 2 lived in remote areas.Of the remaining 44 patients,Groupl instrumentation 24 cases, group2 non-instrumentation 20 cases.Neither of them have preexisting degeneration changes in adjacent segment.Disc degeneration grading on MRI was based on a modified Pfirrmann grade after postoperation.Results:the mean age,BMI have no significant difference between2 groups.Preoperative VAS and ODI score showed no significant difference between 2 groups, and postoperative VAS and ODI score also had no statistically significant difference.The rates of ASD in group 1 (41.7%) are significant higher than group2(10%). Conclusion:1.In single lumbar patients, the use of instrumentation will be obviously improve the rates of upper level degeneration.But there are high rates of pseudoarthrosis without instrumentation.So the condition of the adjacent segments must be considered before surgery.2.Maintaining postoperative segmental lordotic angle after operation and the protection of adjacent segment compounds are important to prevention of clinical ASD.3.In retrospective study, lots of patients have radiograph ASD but a few of them have clinical symptoms.4.Previously reported risk factor, like older age and female gender, is not a risk factor for ASD compared surgery risk factor, if there was no apparent degenerative change at adjacent segments before surgery.5.Magnetic resonance imaging (MRI) is a noninvasive and accurate method for evaluating ASD.