Accelerated L5-S1 Segment Degeneration after Spinal Fusion on and above L4-5 : Minimum 4-Year Follow-Up Results

OBJECTIVE: Many biomechanical and clinical studies on adjacent segment degeneration (ASD) have addressed cranial segment. No study has been conducted on caudal segment degeneration after upper segment multiple lumbar fusions. This is a retrospective investigation of the L5-S1 segment after spinal fusion at and above L4-5, which was undertaken to analyze the rate of caudal ASD at L5-S1 after spinal fusion on and above L4-5 and to determine that factors that might have influenced it. METHODS: The authors included 67 patients with L4-5, L3-5, or L2-5 posterior fusions. Among these patients, 28 underwent L4-5 fusion, 23 L3-5, and 16 L2-5 fusions. Pre- and postoperative radiographs were analyzed to assess degenerative changes at L5-S1. Also, clinical results after fusion surgery were analyzed. RESULTS: Among the 67 patients, 3 had pseudoarthrosis, and 35 had no evidence of ASD, cranially and caudally. Thirteen patients (19.4%) showed caudal ASD, 23 (34.3%) cranial ASD, and 4 (6.0%) both cranial and caudal ASD. Correlation analysis for caudal ASD at L5-S1 showed that pre-existing L5-S1 degeneration was most strongly correlated. In addition, numbers of fusion segments and age were also found to be correlated. Clinical outcome was not correlated with caudal ASD at L5-S1. CONCLUSION: If caudal and cranial ASD are considered, the overall occurrence rate of ASD increases to 50%. The incidence rate of caudal ASD at L5-S1 was significantly lower than that of cranial ASD. Furthermore, the occurrence of caudal ASD was found to be significantly correlated with pre-existing disc degeneration.

Posterior single segment fusion or non-fusion in treatment of lumbar spinal disease:a comparative study / 中国矫形外科杂志

[Objective]To compare the treatment effects between posterior single segment fusion or non-fusion in lumbar spinal disease,and to evaluate their influence on adjacent segments.[Method]Thirty-two cases of degenerative lumbar spinal disorders were treated with Coflex(group non-fusion) and PLIF(group fusion),and followed up for over 2 years.The clinical effect was evaluated by visual analogue scale(VAS) and Oswestry disability index(ODI).Range of motion(ROM) of lumbar segments was measured by X-ray film.[Result]In group non-fusion,VAS decreased from 7.8?1.2 pre-operatively to 2.1?0.6 at final follow-up,ODI from 30.8?3.2 to 4.6?1.2,ROM improved significantly.In group fusion,VAS decreased from 7.2?1.1 to 2.0?0.6,ODI from 29.9?3.0 to 4.5?0.9,and ROM of L3、4 improved significantly.No significant difference of clinical effect was found between 2 groups.[Conclusion]Both fusion and non-fusion fixation have satisfying effects in treatment of degenerative lumbar spinal disorder.Non-fusion fixation has less influence on ROM of lumbar segments and could reduce adjacent segment degeneration.

Relationship between adjacent segment degeneration and clinical outcome after lumbar spine fusion / 中国矫形外科杂志

[Objective] To determine the relationship between the adjacent segment degeneration(ASD)and the clinical outcome after lumbar spine fusion.[Methods]Totally 436 patients undergoing posterolateral lumbar fusion were followed up for 58.13 months(26~114 months).The patients were divided into 3 groups according to the number of the fusion segments:1 segment,2 segments and 3 or more segments.UCLA grading scale was used to evaluate the degeneration of the adjacent segments.Cinical outcome was evaluated according to the criteria established by Hou SH.[Results]Adjacent segment degeneration(ASD)occurred in 58 patients,including 14 in group A,27 in group B and 17 in group C.Forty-nine patients had their ASD above the fusion level and 9 below the fusion level.For all the 14 patients in group A,the degenerative grade increased by 1 grade.Of the 27 patients in group B,16 increased by 1 grade,7 by 2 grades,and 4 by 3 grades.Of the 17 patients in group C,4 increased by 1 grade,8 by 2 grades and 5 by 3 grades.For the clinical outcome,7 patients in group A increased by 1 grade.In group B,13 patients increased by 2 grade and 5 patients increased by 3 grades.For the clinical effect degrees,7 cases decreased by 1 degree in group A.In group B,13 cases decreased by 1 degree and 6 decreased by 2 degrees.[Conclusion]No significant relationship was found between the adjacent segment degeneration and the clinical outcome.Careful attention is needed for avoidance of multi-segmental fusion.

Clinical Comparison of Posterolateral Fusion with Posterior Lumbar Interbody Fusion

OBJECTIVE: The purpose of this study is to compare the outcomes of two methods for stabilization and fusion: Postero-Lateral Fusion (PLF, pedicle screw fixation with bone graft) and Posterior Lumbar Interbody Fusion (PLIF, cage insertion) for spinal stenosis and recurred disc herniation except degenerative spondylolisthesis. METHODS: Seventy one patients who underwent PLF (n=36) or PLIF (n=35) between 1997 and 2001 were evaluated prospectively. These two groups were compared for the change of interbody space, the range of segmental angle, the angle of lumbar motion, and clinical outcomes by Prolo scale. RESULTS: The mean follow-up period was 32.6 months. The PLIF group showed statistically significant increase of the interbody space after surgery. However, the difference in the change of interbody space between two groups was insignificant (P value= 0.05). The range of segmental angle was better in the PLIF group, but the difference in the change of segmental angle was not statistically significant (P value=0.017). Angle of lumbar motion was similar in the two groups. Changes of Prolo economic scale were not statistically significant (P value=0.193). The PLIF group showed statistically significant improvement in Prolo functional scale (P value=0.003). In Prolo economic and functional scale, there were statistically significant relationships between follow-up duration (P value<0.001), change of interbody space (P value<0.001), and range of segmental angle (P value<0.001). CONCLUSION: Results of this study indicate that PLIF is superior to PLF in interbody space augmentation and clinical outcomes by Prolo functional scale. Analysis of clinical outcomes showed significant relationships among various factors (fusion type, follow-up duration, change of interbody space, and range of segmental angle). Therefore, the authors recommend instrumented PLIF to offer better clinical outcomes in patients who needed instrumented lumbar fusion for spinal stenosis and recurred disc herniation.

Adjacent Segment failure after Lumbar Spine Fusion: Controlled Study for Risk Factors / 대한정형외과학회잡지

PURPOSE: To verify the risk factors associated with adjacent segment failure after lumbar spine fusion using pedicle screws. MATERIALS AND METHODS: The study group consisted of 35 patients who underwent lumbar spine fusion using pedicle screws and required revision surgery due to adjacent segment failure. These were compared with 73 control patients who were stratified according to the aspect of the surgical method and period. Gender, age, surgical procedures, the number of fusion segments, the fixation of the sacrum, initial instability and degeneration of the adjacent segments, lumbar lordosis, whole lumbar spondylosis, placement of most proximal screws, habitat, the demand of physical work, physical exercise, smoking, life style and BMI were reviewed retrospectively. RESULTS: Multivariate logistic regression showed that insufficient lumbar lordosis (odds ratio=3.041), instability of the distal adjacent segment (odds ratio=17.196), physically demanding jobs (odds ratio=2.462), delinquent exercise (odds ratio=2.534) and rural habitat (odds ratio=46.729) were associated with an increased incidence of adjacent segment failure. CONCLUSION: Insufficient lordosis, instability of the distal adjacent segment, physically demanding jobs, delinquent exercise and rural habitat were found to be risk factors. The postoperative life style has a large impact on adjacent segment failure. The extension of fusion to an unstable distal segment should be deliberated even though it is not attributable to the current symptoms. A reconstruction of the proper lordosis far outweights the other methodological factors.