Analysis of Risk Factors for Adjacent Segment Degeneration Occurring More than 5 Years after Fusion with Pedicle Screw Fixation for Degenerative Lumbar Spine

Abstract

Study DesignA retrospective study.PurposeWe investigated the risk factors in adjacent segment degeneration (ASD) after more than 5 years of follow-up of lumbar spinal fusion.Overview of LiteratureThere are many concerns regarding ASD followed by lumbar spinal fusion. However, there is a great deal of dispute about the risk factors.MethodsA total of 55 patients who were followed up for more than 5 years after lumbar fusion were observed. Gender, age, residence, fusion method, number of fusion segments and radiological measurements were analyzed. In the radiological measurement, disc height, lumbar lordotic angle (LLA), fusion segment lordotic angle and fusion segment lordotic angle per level (FSLA per level) were estimated. In preoperative MRI, Pfirrmann's classification was used. The clinical result was evaluated by the criteria of Kim and Kim. Statistical univariate analysis was performed with the chi-square test by using SPSS ver. 12.0. Multivariate logistic regression analysis was conducted with SAS ver. 9.ResultsThere were 21 patients with adjacent segment degeneration. Further, there was little relationship between ASD and gender, age, residence, fusion method, number of fusion segments, degree of preoperative adjacent disc degeneration in MRI, or preoperative and postoperative LLA. However, the frequency of ASD was significantly low in cases where FSLA per level was >15° (p=0.009). There was no significant relationship between ASD and the clinical result.ConclusionsIn patients followed up for more than 5 years after lumbar spinal fusion, the most important factor in the prevention of ASD was the restoration of FSLA per level to >15°.

3D point cloud in the evaluation of processes that generate instability of the lumbar spine

“…These findings are confirmed by those of Soh et al, 22 who found that the main disadvantages of surgical fusion in degenerative instability are the loss of mobility and curvature with deterioration of sagittal balance, instrumentation failure, and increased transfer of stress to the adjacent movable segments, referred to as "transition syndrome". They conducted a five-year follow-up with patients who had undergone posterior instrumentation surgery, and showed degenerative changes in adjacent segments due to loss of mobility and changes in mechanical load at the fusion site.…”

“…The degenerative changes in the adjacent segments included segmental instability, spinal stenosis, intervertebral disc injury, spondylolisthesis, and fractures. 22 A measurement is needed that is sensitive to the initial degenerative changes, therefore quantitative MRI analysis has been developed to capture early disc degeneration. The method introduced by Sobajima measures the surface area and intensity of the signal of the pulpy nucleus in patients with changes with symptoms of adjacent disc degeneration, and the results provide an index for T2-weighted magnetic resonance images, 23 from which a correlation can be drawn between the intensity of the signal in magnetic resonance images (MRI) and the composition and condition of the disc.…”

Unilaterally posterior lumbar interbody fusion with double expandable peek cages without pedicle screw support for lumbar disc herniation

“…Its reported incidence is 5.2-29% [29][30][31]. In our study, radicular symptoms were not observed in any of the patients who underwent PLIF thus MRI was not needed.…”

Does hybrid fixation prevent junctional disease after posterior fusion for degenerative lumbar disorders? A minimum 5-year follow-up study

“…Degenerative changes at the adjacent segments were considered to exist when there were at least two of the following criteria: (1) on standing X-rays, the height of the adjacent disc reduced more than 70 %; (2) displacement more than 3 mm on the X-ray of the sagittal plane of the closest upper or lower segment; (3) segmental instability of more than 15°on the lateral X-rays in flexion and extension [3,19]; (4) segmental stenosis and/ or disc degeneration (grade III according Pfirmann classification [20]) at adjacent level on the follow-up MRI. Overall lumbar measures from the radiographs included lumbar lordosis (L1-L5), pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS).…”