Clinical Adjacent Segment Degeneration Research Articles

Incidence and Characteristics of Clinical L5-S1 Adjacent Segment Degeneration after L5 Floating Lumbar Fusion: A Multicenter Study.

Retrospective study. This study aimed to evaluate the incidence, characteristics, and risk factors for clinical L5-S1 adjacent segment degeneration (ASD) after L5 floating lumbar fusion. ASD is known to occur after lumbar spine fusion at a certain frequency. Several studies on radiological L5- S1 ASD have been reported. However, there are only a few studies on L5-S1 ASD with clinical symptoms, including back pain and/or radiculopathy. In total, 306 patients who received L5 floating lumbar fusion were included in this study. Clinical L5-S1 ASD was defined as newly developed radiculopathy in relation to the L5-S1 segment. Patients' medical records and imaging data were retrospectively analyzed. The risk factors for clinical ASD were assessed by an inverse probability of treatment weighting-adjusted logistic regression analysis. Clinical L5-S1 ASD occurred in 17 patients (5.6%). The mean onset time of L5-S1 ASD was 12.9±7.5 months after the primary surgery. Among these patients, 10 (58.8%) presented with clinical L5-S1 ASD within 12 months. Reoperation was performed in three patients (1.0%). The severity of L5-S1 disk degeneration did not affect the occurrence of L5-S1 ASD. Logistic regression analysis showed that the number of fusion levels was a significant risk factor for clinical L5-S1 ASD. The incidence and characteristics of clinical L5-S1 ASD after L5 floating lumbar fusion were retrospectively investigated. This study established that the number of fusion levels was a significant candidate factor for clinical L5-S1 ASD. Careful clinical follow-up is deemed necessary after L5 floating lumbar fusion surgery, especially for patients who received multiple-level fusions.

A descriptive study on the adjacent segment degeneration related signs following a lumbar fusion procedure.

Adjacent segment degeneration (ASD) is a frequent complication following vertebral fusion procedures and is defined as the condition where patients recover after the initial procedure but develop compatible symptoms with radiological injuries in the segments adjacent to the fused ones at a later stage. The objective of the study was to describe the frequency and analysis of ASD related signs following a lumbar fusion procedure. Observational descriptive retrospective study on patients with degenerative or instability conditions, operated on by posterolateral or circumferential lumbar fusion procedure. Pedicle screws, interbody peek cages (polyether-ether-ketone) and autologous bone graft were used. Clinical (pain and disability) and radiological (instability, rotation, disc height loss, radiological degeneration evaluated by X-ray and MR) variables were analysed. Postoperative disc height loss was observed in 159 free discs among 112 patients (42.6%) (95% CI: 36.4-48.8%). Anterior or posterior slippage (anterolisthesis or retrolisthesis) at the end of the follow-up period was observed in 33 patients (12.5%). Upper segment rotation increased in the postoperative period in 36 patients (13.6%). Radiological disc degeneration was observed in 107 discs among 72 patients, being more frequent in the immediate upper disc with grade 2 and 3 changes at the end of follow-up in 48 discs from 35 patients (13.6%) (95% CI: 13.4-23.1%). Radiological ASD signs were observed in 151 patients (57.4%; 95% CI: 51.2-63.6%) and 53 of them (20.2%; 95% CI: 15.1-25.2%) who also showed clinical ASD symptoms (clinical and radiological ASD). Degeneration changes with degrees IV and V shown by a preoperative and magnetic resonance (MR) study at end of the follow-up period performed in 73 patients (27.7%), were observed in 46 discs among 32 patients (43.8%) (95% CI: 31.8-55.9%). Radiological ASD signs evaluated in every free disc following a lumbar fusion procedure are observed with a variable frequency. All free discs after fusion were assessed as they could indicate mechanisms of compensation of lordosis loss and should be taken into consideration in a prospective revision surgery.

Subsidence of anchored cage after anterior cervical discectomy.

Cage subsidence (CS) represents arisk factor for adjacent segment degeneration (ASD) and unfavorable results of anterior cervical discectomy (ACD). Sixty-one patients after level 1 or 2 of ACD with implantation of Zero Profile VA cage were included in the study. CS was assessed witha follow-up period of 12 months after ACD. The impacts of factors such assex, age, number of operated segments, osteoporosis and extent of peroperative distraction were assessed in relation to the incidence of CS. The influences of CS on clinical results (VAS, NDI, Odom's criteria) and ASD incidence were evaluated. In 74 % of cases there was the presence of CS into both adjacent vertebral bodies. CS into the ventral part of motion segment was dominant during the entire follow-up period. CS had no influence on clinical results of ACD. Parallel CS into both ventral and dorsal parts of motion segments significantly increased the incidence of proximal ASD (p = 0.0163). Osteoporosis and extent of peroperative distraction were linked to higher incidence of CS into the dorsal part of motion segment (p ˂ 0.05). Osteoporosis and the extent of peroperative distraction are risk factors for the subsidence of anchored cage and while increasing the incidence of proximal adjacent segment degeneration it has no significant influence on clinical results of surgery (Tab. 3, Fig. 5, Ref. 32).

A comparative study of adjacent segment degeneration following discectomy and instrumented fusion in lumbar Spine

Adjacent segment degeneration following lumbar spine fusion and lumbar discectomy remains a widely known problem, but due to insufficient knowledge regarding the factors that contribute to its occurrence it is difficult to diagnose considering the fact that it has variable presentation in terms of the symptoms it produces, the time frame for its occurance and radiological changes. Our study shows that both in single level discectomy and post instrumented fusion and is marginally more in post single level discectomy without fusion. In both groups cephalic segment is more affected as compared to the caudad segment. There is a significant relationship between radiological degeneration and the clinical adjacent segment degeneration. It has been seen that there is a significant relation between degeneration and chronic smokers both radiologically and clinically. Since there is only marginally difference, we hold on to our hypothesis that the role of natural degeneration is more compared to the role of instrumented fusion causing adjacent segment degeneration. Thus we have to rule out natural and post surgical causes of adjacent segment degeneration leading to different clinical complaints of the patient and manage it accordingly.

Adjacent segment degeneration after posterior lumbar fusion: An analysis of possible risk factors

ObjectiveMany surveys have been distributed about the risk factors for adjacent segment degeneration (ASD) after lumbar fusion. Despite myriad of risk factors recognized for ASD evolution, study results have been inconsistent and there is not an agreement regarding which are the most important. Our study was done to identify factors which may be important in the development of symptomatic ASD after lumbar fusion. Patients and methodsThis retrospective study evaluated 1250 consecutive patients who underwent posterior lumbar fusion and pedicular fixation between February 2006 and February 2009. A total of 13 patients with symptomatic ASD (clinical ASD) who underwent secondary surgery were identified. Another group of 22 patients without symptomatic ASD (subclinical ASD) after spinal fusion were marked as the control group. These two groups were compared for demographic data and clinical and radiographic features to investigate the possible predictive factors of symptomatic ASD. ResultsThe overall incidence rate of symptomatic ASD was 1.04%. Radiographic risk factors for the development of a symptomatic ASD were increased sagittal balance, loss of lordosis, and adjacent disc space collapse. In the clinical ASD group, by multivariate logistic regression analysis, demonstrated that BMI, preoperative ADD on MRI and disc bulge maintained their significance in predicting likelihood of clinical ASD. ConclusionPatients with increased BMI, preoperative ADD and disc bulge on MRI have a statistically significant increased risk of developing symptomatic ASD.

Reduction in adjacent-segment degeneration after multilevel posterior lumbar interbody fusion with proximal DIAM implantation.

OBJECT Multilevel long-segment lumbar fusion poses a high risk for future development of adjacent-segment degeneration (ASD). Creating a dynamic transition zone with an interspinous process device (IPD) proximal to the fusion has recently been applied as a method to reduce the occurrence of ASD. The authors report their experience with the Device for Intervertebral Assisted Motion (DIAM) implanted proximal to multilevel posterior lumbar interbody fusion (PLIF) in reducing the development of proximal ASD. METHODS This retrospective study reviewed 91 cases involving patients who underwent 2-level (L4-S1), 3-level (L3-S1), or 4-level (L2-S1) PLIF. In Group A (42 cases), the patients received PLIF only, while in Group B (49 cases), an interspinous process device, a DIAM implant, was put at the adjacent level proximal to the PLIF construct. Bone resection at the uppermost segment of the PLIF was equally limited in the 2 groups, with preservation of the upper portion of the spinous process/lamina and the attached supraspinous ligament. Outcome measures included a visual analog scale (VAS) for low-back pain and leg pain and the Oswestry Disability Index (ODI) for functional impairment. Anteroposterior and lateral flexion/extension radiographs were used to evaluate the fusion status, presence and patterns of ASD, and mobility of the DIAM-implanted segment. RESULTS Solid interbody fusion without implant failure was observed in all cases. Radiographic ASD occurred in 20 (48%) of Group A cases and 3 (6%) of Group B cases (p < 0.001). Among the patients in whom ASD was identified, 9 in Group A and 3 in Group B were symptomatic; of these patients, 3 in Group A and 1 in Group B underwent a second surgery for severe symptomatic ASD. At 24 months after surgery, Group A patients fared worse than Group B, showing higher mean VAS and ODI scores due to symptoms related to ASD. At the final follow-up evaluations, as reoperations had been performed to treat symptomatic ASD in some patients, significant differences no longer existed between the 2 groups. In Group B, flexion/extension mobility at the DIAM-implanted segment was maintained in 35 patients and restricted or lost in 14 patients, 5 of whom had already lost segmental flexion/extension mobility before surgery. No patient in Group B developed ASD at the segment proximal to the DIAM implant. CONCLUSIONS Providing a dynamic transition zone with a DIAM implant placed immediately proximal to a multilevel PLIF construct was associated with a significant reduction in the occurrence of radiographic ASD, compared with PLIF alone. Given the relatively old age and more advanced degeneration in patients undergoing multilevel PLIF, this strategy appears to be effective in lowering the risk of clinical ASD and a second surgery subsequent to PLIF.

Survival rates and risk factors for cephalad and L5-s1 adjacent segment degeneration after L5 floating lumbar fusion : a minimum 2-year follow-up.

ObjectiveAlthough the L5-S1 has distinct structural features in comparison with other lumbar spine segments, not much is known about adjacent segment degeneration (ASD) at the L5-S1 segment. The aim of study was to compare the incidence and character of ASD of the cephalad and L5-S1 segments after L5 floating lumbar fusion.MethodsFrom 2005 to 2010, 115 patients who underwent L5 floating lumber fusion were investigated. The mean follow-up period was 46.1 months. The incidence of radiological and clinical ASD of the cephalad and the L5-S1 segments was compared using survival analysis. Risk factors affecting ASD were analyzed using a log rank test and the Cox proportional hazard model.ResultsRadiological ASD of the L5-S1 segment had a statistically significant higher survival rate than that of the cephalad segment (p=0.001). However, clinical ASD of the L5-S1 segment was significantly lower survival rates than that of the cephalad segment (p=0.038). Risk factor analysis showed that disc degeneration of the cephalad segment and preoperative spinal stenosis of the L5-S1 segment were risk factors.ConclusionIn L5 floating fusion, radiological ASD was more common in the cephalad segment and clinical ASD was more common in the L5-S1 segment. At the L5-S1 segment, the degree of spinal stenosis appears to be the most influential risk factor in ASD incidences, unlike the cephalad segment.

Disc Space Excessive Distraction is a Potent Risk Factor for Adjacent Segment Degeneration after Anterior Cervical Discectomy and Fusion

Introduction We reported that excessive disc space distraction caused by insertion of large cages during anterior cervical discectomy and fusion (ACDF) induces adjacent segment degeneration (ASD). Previous reports indicated that over distraction of disc space was an independent risk factor for ASD after posterior lumbar interbody fusion. We therefore hypothesize that the incidence of ASD after ACDF with larger size of cages should be higher than that ACDF with normal cages due to this loss of disc space distraction. Materials and Methods Radiographic ASD is defined as development of spondylolisthesis &gt;3 mm, decrease in disc height &gt;3 mm, or intervertebral angle at flexion lesser than −5 degrees. Symptomatic ASD is defined by a decrease of ≥ 4 points in Japanese Orthopedic Association score. A 130 patients with cervical spondylotic radiculopathy were treated with either ACDF with larger size of cages ( n = 45) or ACDF with normal cages ( n = 85) and followed up for a minimum of 2 years (mean, 39.2 months). Results Disc space distraction in the normal cage group was significantly smaller (0.4 mm) as compared with the larger size group (1.8 mm). The incidence of clinical ASD in the normal cage group (2%, 1/45) was also significantly less than that in the larger size group (15%, 13/85). Multivariate analysis showed that disc space distraction was the most significant risk factor. Conclusion Among various risk factors for ASD after ACDF, the excessive distraction of disc space proved to be a potent risk factor for ASD. Disclosure of Interest None declared

Anterior bone cement augmentation in anterior lumbar interbody fusion and percutaneous pedicle screw fixation in patients with osteoporosis

The purpose of the present study was to evaluate the efficacy of anterior polymethylmethacrylate (PMMA) cement augmentation in instrumented anterior lumbar interbody fusion (ALIF) for patients with osteoporosis. Sixty-two patients with osteoporosis who had undergone single-level instrumented ALIF for spondylolisthesis and were followed for more than 2 years were included in the study. The patients were divided into 2 groups: instrumented ALIF alone (Group I) and instrumented ALIF with anterior PMMA augmentation (Group II). Sixty-one patients were interviewed to evaluate the clinical results, and plain radiographs and 3D CT scans were obtained at the last follow-up in 46 patients. The mean degree of cage subsidence was significantly higher in Group I (19.6%) than in Group II (5.2%) (p = 0.001). The mean decrease of vertebral body height at the index level was also significantly higher in Group I (10.7%) than in Group II (3.9%) (p = 0.001). No significant intergroup differences were observed in the incidence of radiographic adjacent-segment degeneration (ASD) or in terms of pain and functional improvement. The incidences of clinical ASD (23% in Group I and 10% in Group II) were not significantly different. There was 1 case of nonunion and 3 cases of screw migration in Group I, but none resulted in implant failure. Anterior PMMA augmentation during instrumented ALIF in patients with osteoporosis was useful to prevent cage subsidence and vertebral body collapse. In addition, PMMA augmentation did not increase the nonunion rate and incidence of ASD.

Risk Factors and Surgical Treatment for Symptomatic Adjacent Segment Degeneration after Lumbar Spine Fusion

The present study analyzed the risk factors, prevalence and clinical results following revision surgery for adjacent segment degeneration (ASD) in patients who had undergone lumbar fusion. Over an 8-year period, we performed posterior lumbar fusion in 81 patients. Patients were followed a minimum of 2 years (mean 5.5 years). During that time, 9 patients required revision surgery due to ASD development. Four patients underwent autogenous posterolateral arthrodesis and extended transpedicle screw fixation, 4 patients underwent decompressive laminectomy and interspinous device implantation, and 1 patient underwent simple decompression. Of the 9 of patients with clinical ASD, 33.3% (3 of 9) of patients did not have radiographic ASD on plain radiographs. Following revision surgery, the clinical results were excellent or good in 8 patients (88.9%). Age > 50 years at primary surgery was a significant risk factor for ASD development, while number of fusion levels, initial diagnosis and type of fusion were not. The incidence of ASD development after lumbar surgery was 11.1% (9 of 81) in this study. Age greater than 50 was the statistically significant risk factor for ASD development. Similar successful clinical outcomes were observed after extended fusion with wide decompression or after interspinous device implantation. Given the latter procedure is less invasive, the findings suggest it may be considered a treatment alternative in selected cases but it needs further study.

The Impact of Adjacent Segment Degeneration on the Clinical Outcome After Lumbar Spinal Fusion

A retrospective study. To determine the impact of the adjacent segment degeneration (ASD) on the clinical outcome after lumbar fusion. Few studies have analyzed correlation between clinical outcomes and ASD. From January 2000 to December 2004, 217 patients who underwent lumbar fusion and have more than 2 years of follow-up were evaluated. The patients were divided into 3 groups: fusion was carried out on 1 (A), 2 (B), and more than 3 segments (C). UCLA grading scale was used to evaluate the ASD on radiograph preoperative, postoperative, and last follow-up. The clinical outcome was evaluated and the association between clinical outcome and ASD was evaluated by the Spearman correlation. ASD occurred 11.6% (13/112 cases) in group A, 14.5% (9/62 cases) in group B, and 16.3% (7/43 cases) in group C. Among them, the cases which had progressed more than 2 level of degenerative grade were 0 in group A, 7 cases (77.8%) in group B, and 6 cases (85.7%) in group C. In group A, 5 cases with ASD had down graded 1 level in clinical outcome. In group B, all 9 cases with ASD had down graded more than 1 level in clinical outcome; 1 level aggravation in 1, 2 level in 5, and 3 level in 1 case. In group C, all 7 cases with ASD also had down graded more than 1 level in clinical outcome; 1 level aggravation in 2, 2 level in 5 cases. Finally, the more the change of the degenerative grade is severe, the more the clinical outcome is worse (P < 0.05). The impact of ASD on clinical outcome after fusion showed a significant correlation, especially with the ASD after multiple-segments fusion. Careful attention is needed in multiple-segments fusion such as degenerative lumbar deformity.

Correlation Between Clinical Result and Adjacent Segment Degeneration After Lumbar Spinal Fusion

Study Design: Retrospective study Objectives: To determine the relationship between clinical outcome and adjacent segment degeneration (ASD) after lumbar fusion. Summary of Literature Review: Few studies have analyzed the correlation between clinical outcomes and ASD. Materials and Methods: Between January 2000 and December 2004, 217 patients who underwent lumbar spinal fusion (�2 years of follow-up) were evaluated. The patients were divided into 2 groups: one-segment (A) and two-segment (B). The UCLA grading scale was used to evaluate the prevalence of ASD on radiography. The association between clinical outcome and ASD was evaluated by Spearman’s correlation. Results: ASD occurred in 11.6% (13/112) of patients in group A and 15.2% (16/105) of patients in group B. The number of cases which progressed to more than 2 levels of the degenerative grade were 0 cases in group A and 13 cases (81.3%) in group B. In A, 5 out of 13 ASD cases downgraded one level in their clinical outcomes. In B, all 16 ASD cases downgraded more than one level in their clinical outcomes. Worsening in degenerative grade, was correlated with worse clinical outcome (Spearman’s rho = 0.829, P �0.05). Conclusions: The association of clinical outcomes with ASD after fusion showed a significant correlation, especially association with ASD after multiple segment fusion.