Prevalence Of Adjacent Segment Disease Research Articles

The Prevalence of Adjacent Segment Disease and Reoperation Following Transpedicular Screw Fixation of Lumbar Spine

The Prevalence of Adjacent Segment Disease and Reoperation Following Transpedicular Screw Fixation of Lumbar Spine

Effect of segmental lordosis on early-onset adjacent-segment disease after posterior lumbar interbody fusion.

Although several reports have described adjacent-segment disease (ASD) after posterior lumbar interbody fusion (PLIF), there have been only a few reports focusing on early-onset ASD occurring within 3 years after primary PLIF. The purpose of this study was to investigate the prevalence and postoperative pathologies of early-onset ASD and its relation with radiological parameters such as segmental lordosis (SL). The authors reviewed a total of 256 patients who underwent single-segment PLIF at L4-5 for degenerative lumbar spondylolisthesis (DLS) and were followed up for at least 5 years. The definition of ASD was a symptomatic condition requiring an additional operation at the adjacent fusion segment in patients who had undergone PLIF. ASD occurring within 3 years after primary PLIF was categorized as early-onset ASD. As a control group, 54 age- and sex-matched patients who had not suffered from ASD for more than 10 years were selected from this series. There were 42 patients with ASD at the final follow-up. ASD prevalence rates at 3, 5, and 10 years postoperatively and at the final follow-up were 5.0%, 8.2%, 14.1%, and 16.4%, respectively. With respect to ASD pathologies, lumbar disc herniation (LDH) was significantly more common in early-onset ASD, while lumbar spinal stenosis and DLS occurred more frequently in late-onset ASD. Significant differences were detected in the overall postoperative range of motion (ROM) and in the changes in ROM (ΔROM) at L3-4 (the cranial adjacent fusion segment) and changes in SL (ΔSL) at L4-5 (the fused segment), while there were no significant differences in other pre- and postoperative parameters. In stepwise logistic regression analysis, ΔSL was identified as an independent variable (p = 0.008) that demonstrated significant differences, especially in early-onset ASD (control 1.1° vs overall ASD -2.4°, p = 0.002; control 1.1° vs early-onset ASD -6.6°, p = 0.00004). The study results indicated that LDH was significantly more common as a pathology in early-onset ASD and that ΔSL was a major risk factor for ASD, especially early-onset ASD.

Dynamic Fixation Techniques for the Prevention of Adjacent Segment Disease: A Retrospective Controlled Study.

Study DesignRetrospective, controlled study.PurposeDynamic fixation (topping-off technique) adjacent to a transforaminal lumbar interbody fusion (TLIF) level was developed to reduce the risk of adjacent segment disease (ASDi). This study was designed to compare the clinical and radiological outcomes between patients who underwent circumferential lumbar fusion (CLF) without the topping-off technique, CLF with dynamic rod constructs (DRC), and CLF with interspinous device (ISD).Overview of LiteratureLumbar fusion can result in the re-distribution of stress, increased mobility, and increased intradiscal pressure at adjacent levels, ultimately leading to adjacent segment degeneration (ASDe) and ASDi. Dynamic fixation techniques (topping-off techniques) adjacent to vertebral fusion have been developed to reduce the risk of ASDe and ASDi because they provide a transitional zone between a caudal rigid fused segment and cephalad-mobile unfused levels.MethodsA single-center, retrospective, controlled study was designed, including all patients who underwent CLF due to degenerative lumbar spinal disease in Hospital Clinic of Barcelona between 2012 and 2018. Three groups of patients were evaluated as per the type of topping-off technique used: CLF alone group, DRC group, and ISD group. Clinical and radiological outcomes were evaluated.ResultsA total of 117 patients were enrolled in the study. Sixty patients (51.3%) underwent CLF without dynamic stabilization, 24 (20.5%) were treated with DRC as topping-off technique, and 33 (28.5%) were treated with an ISD. A total of 12 patients (20.0%) in the CLF alone group showed ASDi at the final follow-up, compared to 1 (4.2%) in the DRC group (p=0.097) and 2 (6.1%) in the ISD group (p=0.127). The Cox regression model identified a significantly decreased risk of ASDi when a topping-off technique (DRC or ISD) was used (hazard ratio, 0.154; 95% confidence interval, 0.31–0.77).ConclusionsDynamic fixation adjacent to CLF was a safe and efficient procedure associated with improved clinical outcomes in patients with lumbar spine degenerative disease.

The Efficacy of Lumbar Hybrid Fusion for the Prevention of Adjacent Segment Disease: Fact or Artifact? A Meta-analysis.

A systematic literature review and meta-analysis. The aim of this study is to compare hybrid constructs with traditional fusion-only constructs for the incidence of adjacent segment degeneration (ASDeg) and clinical outcomes in patients with degenerative lumbar diseases. Spinal fusion is a standard surgery for various pathologies of the lumbar spine, which results in changes to the biomechanics of the spine, potentially leading to ASDeg. Although ASDeg can occur slowly as a natural course, early-onset ASDeg is regarded to be related to fusion surgery. A systematic search was conducted to identify studies that match the purpose. Included studies were compared using the incidence of ASDeg, Oswestry Disability Index, Visual Analog Score, and perioperative outcomes. We calculated the Peto odds ratio and mean difference (MD) for the continuous variables, respectively. In the hybrid group, subgroup analysis was also performed among devices. Among 10 papers involving 767 patients, 372 patients underwent hybrid fusion and 395 patients underwent fusion-only. ASDeg occurred in 10.2% in the hybrid and 21.5% in the fusion-only group [Peto odds ratio, 0.39; 95% confidence interval (CI), 0.23-0.64]. The MD for Visual Analog Score were 0.45 (95% CI, 0.05-0.85) between 2 groups, which was statistically significant but was too small to have clinical significance. The MD for Oswestry Disability Index was 0.93 (95% CI, -1.016 to 2.872), which was not statistically different between 2 groups. The hybrid is superior for 18 minutes (95% CI, 5.78-30.72) shorter than typical surgery. Hybrid lumbar surgery decreased the incidence of early-onset ASDeg for about 2 years of follow-up. Among the hybrid constructs, the interspinous devices group accomplished favorable results with a lower risk. Adjacent segment disease was not as statistically significant as ASDeg, but adjacent segment disease may show a substantial difference for >2-year follow-up.

Adjacent-segment disease following two-level axial lumbar interbody fusion.

While long-term studies have evaluated adjacent-segment disease (ASD) following posterior lumbar spine arthrodesis, no such studies have assessed the incidence and prevalence of ASD following axial lumbar interbody fusion (AxiaLIF). The aim of this study was to estimate the incidence of ASD following AxiaLIF. The authors retrospectively reviewed the medical records of 149 patients who underwent two-level index AxiaLIF and had at least 2 years of radiographic and clinical follow-up. ASD and pre- and postoperative lumbar lordosis were evaluated in each patient. ASD was defined as both radiographic and clinically significant disease at a level adjacent to a previous fusion requiring surgical intervention. The mean duration of follow-up was 6.01 years. Twenty (13.4%) of the 149 patients developed ASD during the data collection period. Kaplan-Meier analysis predicted a disease-free ASD survival rate of 95.3% (95% CI 90.4%-97.7%) at 2 years and 89.1% (95% CI 82.8%-93.2%) at 5 years for two-level fusion. A laminectomy adjacent to a fusion site was associated with 5.1 times the relative risk of developing ASD. Furthermore, the ASD group had significantly greater loss of lordosis than the no-ASD group (p = 0.033). Following two-level AxiaLIF, the rate of symptomatic ASD warranting either decompression or arthrodesis was found to be 4.7% at 2 years and 10.9% at 5 years. Adjacent-segment decompression and postoperative loss of lumbar lordosis predicted future development of ASD. To the authors' knowledge, this is the largest reported cohort of patients to undergo two-level AxiaLIF in the United States.

Prevalence of adjacent segment disease following cervical spine surgery: A PRISMA-compliant systematic review and meta-analysis.

Prevalence estimates of adjacent segment degeneration (ASD) following cervical spine surgery varied greatly in current studies. We conducted a systematic review and meta-analysis to summarize the point prevalence of ASD after cervical spine surgery.MethodsComprehensive electronic searches of PubMed, Embase, Web of Knowledge, and Cochrane Library databases were conducted to identify any study published from initial state to January 2016. Those reporting the prevalence of ASD after cervical surgery were included. A random-effects model was used to estimate the prevalence of radiographic ASD, symptomatic ASD, and reoperation ASD. Univariate meta-regression analyses were conducted to explore the potential associations between prevalence and length of follow-up. All analyses were performed using R version 3.2.3 (R Foundation for Statistical Computing).ResultsA total of 83 studies were included in the meta-analysis. The prevalence of radiographic ASD, symptomatic ASD, and reoperation ASD after cervical surgery was 28.28% (95% confidence interval [CI], 20.96–36.96), 13.34% (95% CI, 11.06–16.00), and 5.78% (95% CI, 4.99–6.69), respectively, in a general analysis. It was found 2.79%, 1.43%, and 0.24% additions per year of follow-up in the incidence of radiographic ASD, symptomatic ASD, and reoperation ASD, respectively.ConclusionThis meta-analysis provides some details about the prevalence of radiographic ASD, symptomatic ASD, and reoperation ASD after cervical spine surgery. However, the results of this meta-analysis should be interpreted with caution because of the heterogeneity among the studies.

Posterior dynamic stabilization: The interspinous spacer from treatment to prevention.

Introduction:Managements of lumbar stenosis evoluted over the time from decompression to dynamic stabilization preserving the motion segment passing by the rigid fixation. After long years of rigid fusion, adjacent segment disease became more and more frequent and the concept of dynamic stabilization emerged.Materials and Methods:We report our experience with posterior dynamic stabilization using an interspinous distracter (ISD). One hundred and eight patients were operated between September 2008 and January 2012 with different lumbar spine pathologies. The ages of our patients were between 45 years and 70 years, with a mean age of 55 years. With our growing experience, indication of ISD became narrowed and the interspinous spacer became an absolute tool for adjacent segment disease as a treatment as well as prophylactic with rigid stabilization.Results and Discussion:Overall clinical improvement was noted in ISD-treated patients, with considerable satisfaction in 77% of patients on average. The patient at first reported an improvement of their radicular pain with a mean reduction of 3.6/10 on visual analog scale. Post-operative walking distance progressively increased during the next 3 months. Whereas, a radiological evaluation at 3 months showed a mean of 42% improvement of the disc height. On the other hand, all patients operated with posterior dynamic stabilization (PDS) at the time of rigid stabilization showed no adjacent segment disease compared to those operated with posterior arthrodesis (P < 0.05).Conclusion:Interspinous spacer after surgical decompression for spinal stenosis by excision of Ligamentum flavum demonstrates excellent short-term and long-term results for improvement in back pain, neurogenic claudication, and patient satisfaction. It provides restoration of disc height, reduction of vertebral slip and it's a necessary tool in the management and the prevention of adjacent segment disease.

The M6-C Cervical Disk Prosthesis

Retrospective study. To determine the short-term clinical succesrate of the M6-C cervical disk prosthesis in primary and secondary surgery. Cervical disk arthroplasty (CDA) provides an alternative to anterior cervical decompression and fusion for the treatment of spondylotic radiculopathy or myelopathy. The prevention of adjacent segment disease (ASD), a possible complication of anterior cervical decompression and fusion, is its most cited--although unproven--benefit. Unlike older arthroplasty devices that rely on a ball-and-socket-type design, the M6-C cervical disk prosthesis represents a new generation of unconstrained implants, developed to achieve better restoration of natural segmental biomechanics. This device should therefore optimize clinical performance of CDA and reduce ASD. All patients had preoperative computed tomography or magnetic resonance imaging and postoperative x-rays. Clinical outcome was assessed using the Neck Disability Index, a Visual Analog Scale, and the SF-36 questionnaire. Patients were asked about overall satisfaction and whether they would have the surgery again. Thirty-three patients were evaluated 17.1 months after surgery, on average. Nine patients had a history of cervical interventions. Results for Neck Disability Index, Visual Analog Scale, and SF-36 were significantly better among patients who had undergone primary surgery. In this group, 87.5% of patients reported a good or excellent result and 91.7% would have the procedure again. In contrast, all 4 device-related complications occurred in the small group of patients who had secondary surgery. The M6-C prosthesis appears to be a valuable addition to the CDA armatorium. It generates very good results in patients undergoing primary surgery, although its use in secondary surgery should be avoided. Longer follow-up is needed to determine to what measure this device can prevent ASD.

Analysis of Risk Factors of Adjacent Segment Disease with Lumbar and Lumbosacral Arthrodesis for the Degenerative Lumbar Spinal Disorders

Purpose: The objective of this study is to confirm the effects of risk factors on Adjacent Segment Disease (ASD). Materials and Methods: The subjects of this study were 793 patients who had degenerative lumbar spine disease and were followed-up for an average period of 7.2 years from January of 1999 to September of 2010 after undergoing spinal fusion. To confirm the risk factors, a study on patient factors, surgical factors and radiologic factors was performed. Results: Of 793 patients, 69 patients (group A, 8.7%) underwent a secondary surgical treatment due to ASD. Age of patient, sex, bone mineral density, history of smoking and occupation were not statistically significant. Preoperative body mass index (BMI) (≥25 kg/m 2 ) and postoperative increase of BMI were the patient’s factor in ASD (p=0.02, p＜0.001). Regarding surgical factors, multilevel fusion (more than 3 levels) was higher risk in prevalence of ASD than short level fusion (p=0.01). Degeneration of intervertebral disc (p=0.01) and facet joints (p=0.02), and segmental instability (p=0.001) were also associated with the prevalence of ASD in radiologic factors. Conclusion: To prevent the occurrence of ASD after lumbosacral fusion, selection of the proper level of fusion preoperatively and modifying the life style with body weight control and reduction of hypermobility after fusion surgery are essential.

Combined Dynamic and Rigid Multilevel Posterolateral Lumbar Fixation Systems in Prevention of Adjacent Segment Disease

Introduction: The gold standard in the treatment of lumbar degenerative spinal diseases is the posterolateral fusion with rod and screws. Semi-rigid systems were first designed to stabilize the abnormal segment and to unload degenerated discs and facet joints. One commonly observed consequence of fusing spinal motion levels has been adjacent segment disease (ASD). Due to prevention of ASD is a complicated and controversial topic, the aim of this study was to assess the role of combined dynamic and rigid posterolateral fixation systems in prevention of ASD. Patients and Methods: A total of 76 adult patients with various lumbar spine pathologies, treated with posterior fusion and pedicle screw fixation between T12 and sacrum were included in this study. The prevalence of radiological and clinical ASD was measured and the functional outcome of the patients was evaluated using the Oswestry questionnaire. Results: Evidence of radiographic ASD was noted in 6 of the 76 patients (7.9%), of whom one patient was symptomatic (16.67%). The mean preoperative Oswestry score was 27.2 ± 20.7 and the mean postoperative Oswestry score was 15.4 ± 20.3. There was a significant difference between the 2 scores (p=0.027). The mean postoperative lumbar lordosis was -53° ± 2.08 and the pelvic incidence 61° ± 3.12. Related to the complications, 6 patients with superficial wound infections, one patient with deep venous thrombosis (DVT), and one patient with ASD were reported. Discussion: In our study, the very low incidence of ASD is achieved by the mean of preservation of the top facet joint, correction and preservation of coronal and sagittal balance, preservation of motion in the lumbar spine with the use of semi-rigid devices, and early rehabilitation accompanying by the training of the patient regarding to the body balance. Semi-rigid fixation significantly reduces the risk of screw fracture by the absorption of the stress on the interpedicular damper and enhances the bone fusion by maintaining constraints on the cages which remain under a compressive load.

Cervical Disc Arthroplasty: An Overview of Past, Present and Future

Purpose of review: The present article reviews the most recent research into the rationale, patient selection, clinical results and complication profile of cervical arthroplasty. Recent findings: Recent results of prospective randomized control trials comparing cervical disc replacement and anterior fusion have demonstrated safety as well as equal or superior clinical results. In vivo kinematic studies have suggested decreased rates of adjacent segment disease following disc replacement. Increasingly, more studies are examining the complication profile and emerging contra-indications for cervical disc replacement. Summary: Cervical arthroplasty is a promising technique in that is undergoing rapid refinement and development. Further long-term data is eagerly awaited before the role in prevention of adjacent segment disease can be proven.

Biomechanical evaluation of a low-profile, anchored cervical interbody spacer device at the index level or adjacent to plated fusion.

In vitro biomechanical study. To test the hypotheses: (1) an anchored spacer device would decrease motion similarly to a plate-spacer construct, and (2) the anchored spacer would achieve a similar reduction in motion when placed adjacent to a previously fused segment. An anchored spacer device has been shown to perform similar to the plate-spacer construct in previous biomechanical evaluation. The prevalence of adjacent segment disease after fusion is well established in the literature.There is currently no evidence supporting the use of an anchored interbody spacer device adjacent to a previous fusion. Eight human cervical spines (age: 45.1 ± 13.1 yr) were tested in moment control (±1.5 Nm) in flexion-extension, lateral bending, and axial rotation without preload. Flexion-extension was then retested under 150-N preload. Spines were tested intact and after anterior cervical discectomy and fusion (ACDF) at C4-C5 and C6-C7 with either a plate-spacer or anchored spacer construct (randomized). The specimens were tested finally with an ACDF at the floating C5-C6 segment using the anchored spacer device adjacent to the previous fusions. Both the plate-spacer and anchored spacer significantly reduced motion from the intact spine in flexion-extension, lateral bending, and axial rotation (P < 0.005). There was no statistically significant difference between the 2 fusion constructs in their abilities to reduce motions (P = 1.0). ACDF using the anchored spacer at the floating C5-C6 level (in between the plate-spacer and anchored spacer constructs) resulted in significant motion reductions in all modes of testing (P < 0.05). These motion reductions did not significantly differ from those of a single-level anchored-spacer construct or a single-level plated ACDF. The anchored spacer provided significant motion reductions, similar to a plated ACDF, when used as a single-level fusion construct or placed adjacent to a previously plated segment. N/A.

Cell therapy for intervertebral disc repair: advancing cell therapy from bench to clinics.

Intervertebral disc (IVD) degeneration is a major cause of pain and disability; yet therapeutic options are limited and treatment often remains unsatisfactory. In recent years, research activities have intensified in tissue engineering and regenerative medicine, and pre-clinical studies have demonstrated encouraging results. Nonetheless, the translation of new biological therapies into clinical practice faces substantial barriers. During the symposium "Where Science meets Clinics", sponsored by the AO Foundation and held in Davos, Switzerland, from September 5-7, 2013, hurdles for translation were outlined, and ways to overcome them were discussed. With respect to cell therapy for IVD repair, it is obvious that regenerative treatment is indicated at early stages of disc degeneration, before structural changes have occurred. It is envisaged that in the near future, screening techniques and non-invasive imaging methods will be available to detect early degenerative changes. The promises of cell therapy include a sustained effect on matrix synthesis, inflammation control, and prevention of angio- and neuro-genesis. Discogenic pain, originating from "black discs" or annular injury, prevention of adjacent segment disease, and prevention of post-discectomy syndrome were identified as prospective indications for cell therapy. Before such therapy can safely and effectively be introduced into clinics, the identification of the patient population and proper standardisation of diagnostic parameters and outcome measurements are indispensable. Furthermore, open questions regarding the optimal cell type and delivery method need to be resolved in order to overcome the safety concerns implied with certain procedures. Finally, appropriate large animal models and well-designed clinical studies will be required, particularly addressing safety aspects.

Preoperative Predictable Factors for the Occurrence of Adjacent Segment Degeneration Requiring Second Operation after Spinal Fusion at Isolated L4–L5 Level

Retrospective study. The purpose of this study was to clarify (1) the overall prevalence of radiologic and clinical adjacent segment disease (ASD), (2) the prevalence of radiologic ASD at cranial versus caudal adjacent segments, and (3) preoperative risk factors and preoperative radiologic features associated with radiologic disc degeneration of the cranial and caudal adjacent segments. A total of 154 patients who underwent posterior lumbar interbody fusion and screw-rod fixation at the L4-L5 level were retrospectively evaluated more than 2 years after surgery. We analyzed demographic factors and radiographic features. Special focus was preoperative radiographic features of patients who required additional surgery. These patients were studied to detect risk factors for clinical deterioration. Of 154 patients, 103 (66.8%) showed radiologic degeneration at an adjacent segment after surgery-92 (59.7%) at the cranial adjacent segment and 61 (39.6%) at the caudal adjacent segment-and 10 patients (6.4%) required second operation because of radicular pain as well as severe back pain or spinal instability with back pain and neurologic deficits. Age, body mass index (BMI), and preexisting stenosis at the cranial adjacent segment were identified as important risk factors for clinical ASD requiring second operation. Age, BMI, and preexisting stenosis at the cranial adjacent segment were the most important risk factors for clinical ASD requiring a second operation. Careful consideration is warranted when these risk factors are present.

Posterior Transpedicular Dynamic Systems in the Treatment of Chronic Lumbar Instability

Dynamic stabilization is a new concept and a new technology in spinal stabilization. There are a lot of debates on this topic and most of the criticisms may be true; however, it should be kept in mind that every technology develops from necessity. If fusion could solve all the problems, scientists would not try to develop other solutions. Posterior dynamic stabilization is a hopeful technology and we believe that tremendous innovative surgical techniques and surgical instruments will develop in near future. We expect that we will open new horizons in your minds when you are considering treatment plans about your patients which need lumbar stabilization procedures. In this special issue, you will find several examples of dynamic stabilization surgeries for different spinal diseases. Clinical results were also given with expanded review of the relevant literature. The papers in this journal also open a new window about treatment of lumbar disc herniations. Type 2 and type 4 disc herniations, according to the Carragee classification, treated with dynamic stabilization instead of subtotal discectomy were discussed by A. F. Ozer et al. You will find manuscripts in this special issue regarding recurrent disc herniations, painful black discs, degenerative spondylolisthesis, and painful Modic degenerations with degenerative disc disease treated with posterior dynamic stabilization surgery. We believe that dynamic systems will be discussed more intensely in the treatment of degenerative disc and bony pathologies in the lumbar spine. There are a lot of biomechanical and clinical studies about dynamic stabilization systems of the lumbar spine. Recently, finite element studies also have been published frequently concerning these systems. D. U. Erbulut et al. have performed an excellent review on biomechanics of posterior dynamic stabilization systems, and readers will learn too much from this paper in this special issue. We know that load sharing of the spinal column is an important biomechanical factor which may directly affect a patient's pain level, fusion success, and future disease progression, following spine surgery. In this journal, there is also a well-written research about load-sharing and regional load distribution of the interbody area investigating comparisons with between rigid rods, semirigid PEEK rods, and semirigid dynamic posterior instrumentation with flexion-extension dampening materials. There is a very important paper about adult's degenerative scoliosis which concluded that pedicle screw-based dynamic stabilization can be used in elderly patients with mild degenerative lumbar scoliosis because this is a less invasive surgery with short operative duration, moderate blood loss, and low adverse event rates. Moreover, they also reported scoliosis curve stabilization, at an average followup of more than 5 years. It was believed that fusion is a gold standard for low back pain treatment so far. However, there have been several complications reported clinically. These complications mainly are related to pseudoarthrosis and adjacent segment degeneration due to high stiffness at the stabilized segment. As an alternative treatment, nonfusion stabilization systems became more and more popular in order to preserve mobility of a motion segment and eliminate adjacent segment phenomena. You will see research studies emphasizing the benefits of dynamic stabilization system to prevent pseudoarthrosis and adjacent segment disease in this issue. The posterior transpedicular dynamic stabilization method is a very good surgical procedure in the patients with segmental instability. When we consider the biomechanical problems including widening of neutral zone and weakness of parts which stabilize the spine, one can easily understand the effectiveness of dynamic systems in treating patients who have lumbar segmental instability. There are also reports about the benefits of interspinous spacers and the results in terms of pain control, motion preservation, and prevention of adjacent segment degeneration. The authors in this journal recommend its use in treatment as well as in prevention of adjacent segment disease specifically in young patients where spinal fusion for early degenerative disease is needed. We know that dynamic stabilization of the lumbar spine not only stops the degeneration process but also starts the regeneration. L.-Y. Fay et al. reported the rehydration of intervertebral disc after dynamic system surgery using MRI evaluation. These papers prove radiological improvement of the disc tissue after this surgery. Ali Fahir Ozer Vijay K. Goel Ahmet Alanay Mehdi Sasani Tunc Oktenoglu Deniz Erbulut

The Interspinous Spacer: A New Posterior Dynamic Stabilization Concept for Prevention of Adjacent Segment Disease

Introduction. Posterior Dynamic stabilization using the interspinous spacer device is a known to be used as an alternative to rigid fusion in neurogenic claudication patients in the absence of macro instability. Actually, it plays an important in the management of adjacent segment disease in previously fused lumbar spine. Materials and Method. We report our experience with posterior dynamic stabilization using an interspinous spacer. 134 cases performed in our institution between September 2008 and August 2012 with different lumbar spine pathologies. The ages of our patients were between 40 and 72 years, with a mean age of 57 years. After almost 4 years of follow up in our patient and comparing their outcome to our previous serious we found that in some case the interspinous distracter has an important role not only in the treatment of adjacent segment disease but also in its prevention. Results and Discussion. Clinical improvement was noted in ISD-treated patients, with high satisfaction rate. At first, radicular pain improves with more than 3/10 reduction of the mean score on visual analog scale (VAS). In addition, disability score as well as disc height and lordotic angle showed major improvement at 3 to 6 months post operatively. And, no adjacent segment disease was reported in the patient operated with interspinous spacer. Conclusion. The interspinous spacer is safe and efficient modality to be used not only as a treatment of adjacent segment disease but also as a preventive measure in patients necessitating rigid fusion.

Cervical arthroplasty: the beginning, the middle, the end?

Cervical arthroplasty has developed as an alternative to spinal fusion for the treatment of cervical radiculopathy and myelopathy. The popularity of artificial discs has grown as the evidence of complications following arthrodesis has increased, making the theoretical advantages (motion preservation, altering the natural history of disease, prevention of adjacent segment disease) of disc replacement more attractive. However, as more discs are implanted and the length of follow-up increases, reported complications such as heterotopic ossification, device migration and spontaneous fusion of arthroplasty devices are growing. As a result, surgeons and patients face a challenge when deciding between motion-preserving or fusion surgery. Currently, there is inadequate evidence to promote extensive use of artificial discs for cervical spondylosis, despite promising short-term and intermediate clinical outcomes. However, there is also insufficient evidence to cease using them completely. The use of arthroplasty over fusion in the long term can only be justified if the incidence of adjacent segment disease decreases as a result. Despite the level of investment and research into arthroplasty outcomes, long-term follow-up has yet to be completed and has not convincingly demonstrated the effect of artificial discs on adjacent segment disease. Further long-term randomised trials are necessary to determine whether cervical arthroplasty is able to reduce the incidence of adjacent segment disease and, in doing so, replace arthrodesis as the gold standard treatment for cervical spondylosis.

Adjacent Segment Motion After Anterior Cervical Discectomy and Fusion Versus ProDisc-C Cervical Total Disk Arthroplasty

Post hoc analysis of data acquired in a prospective, randomized, controlled trial. To compare adjacent segment motion after anterior cervical discectomy and fusion (ACDF) versus cervical total disc arthroplasty (TDA). TDA has been designed to be a motion-preserving device, thus theoretically normalizing adjacent segment kinematics. Clinical studies with short-term follow-up have yet to demonstrate a consistent significant difference in the incidence of adjacent segment disease. Two hundred nine patients at 13 sites were treated in a prospective, randomized, controlled trial of ACDF versus TDA for single-level symptomatic cervical degenerative disc disease (SCDD). Flexion and extension radiographs were obtained at all follow-up visits. Changes in ROM were compared using the Wilcoxon signed-rank test and the Mann-Whitney U test. Predictors of postoperative ROM were determined by multivariate analysis using mixed effects linear regression. Data for 199 patients were available with 24-month follow-up. The groups were similar with respect to baseline demographics. A significant increase in motion at the cranial and caudal adjacent segments after surgery was observed in the ACDF group only (cranial: ACDF: +1.4° (0.4, 2.4), P = 0.01; TDA: +0.8°, (-0.1, +1.7), P = 0.166; caudal: ACDF: +2.6° (1.3, 3.9), P < 0.0001; TDA: +1.3, (-0.2, +2.8), P = 0.359). No significant difference in adjacent segment ROM was observed between ACDF and TDA. Only time was a significant predictor of postoperative ROM at both the cranial and caudal adjacent segments. Adjacent segment kinematics may be altered after ACDF and TDA. Multivariate analysis showed time to be a significant predictor of changes in adjacent segment ROM. No association between the treatment chosen (ACDF vs. TDA) and ROM was observed. Furthermore clinical follow-up is needed to determine whether possible differences in adjacent segment motion affect the prevalence of adjacent segment disease in the two groups.

Complications Specific to Motion-Sparing Devices in the Lumbar Spine

Motion-sparing technology has gained popularity in recent years. However, the benefits remain theoretic and unproven. Long-term, level I investigations are underway to explore the efficacy and usefulness of such procedures for the prevention of adjacent segment disease. As with any new treatment, appropriate attention must be given to strict surgical indications and proper patient selection. A clear understanding of the various implants and tools available and their associated complications is an essential component of sound spine surgical care.

Incidence and prevalence of surgery at segments adjacent to a previous posterior lumbar arthrodesis

Background context Adjacent segment disease (ASD) after lumbar spinal fusion has been an important reason behind the development of nonfusion stabilization technology. However, the incidence, prevalence, and factors contributing to adjacent segment degeneration in the lumbar spine remain unclear. A range of prevalence rates for ASD have been reported in the lumbar spinal literature, but the annual incidence has not been widely studied in this region. Conflicting reports exist regarding risk factors, especially fusion length. Purpose To determine the annual incidence and prevalence of further surgery for adjacent segment disease (SxASD) after posterior lumbar arthrodesis and examine possible risk factors. Study design Retrospective cohort study. Patient sample Nine hundred twelve patients who underwent 1,000 consecutive posterior lumbar interbody fusion procedures, with mean follow-up duration of 63 months (range, 5 months–16 years). Outcome measures Further surgery for ASD or surgery-free survival. Methods A postal and telephone survey. Follow-up rate: 91% of patients. The annual incidence and prevalence of ASD requiring further surgery were determined using Kaplan–Meier survivorship analysis. Cox proportional-hazards (Cox) regression was used for multivariate analysis of possible risk factors. Significance was set at p<.05. Results Further surgery for ASD occurred following 130 of 1,000 or 13% of procedures at a mean time of 43 months (range, 2.3–162 months). The mean annual incidence of SxASD over the first 10 years, in all patients, was 2.5% (95% confidence interval [95% CI], 1.9–3.1) with prevalences of 13.6% and 22.2% at 5 and 10 years, respectively. Cox regression modeling found that the number of levels fused (p≤.0003), age of the patient, fusing to L5, and performing an additional laminectomy adjacent to a fusion all independently affect the risk of SxASD. The mean annual incidence figures in the first 10 years after a lumbar fusion were 1.7% (95% CI, 1.3–2.2) after fusion at single levels, 3.6% (2.1–5.2) after two levels, and 5.0% (3.3–6.7) after three and four levels. The 5- and 10-year prevalences were 9% and 16%, 17% and 31%, and 29% and 40% after single-, two-, and three-/four-level fusions, respectively. The risk of SxASD in patients younger than 45 years was one-quarter (95% CI, 10–64) the risk of patients older than 60 years (p=.003). A laminectomy adjacent to a fusion increases the relative risk by 2.4 times (95% CI, 1.1–5.2; p=.03). Stopping a fusion at L5 is associated with a 1.7-fold increased risk (95% CI, 1.2–2.4; p=.007) of SxASD compared with a fusion to S1, for fusions of the same length. Conclusion The overall annual incidence and predicted 10-year prevalence of further surgery for ASD after lumbar arthrodesis were 2.5% and 22.2%, respectively. These rates varied widely depending on the identified risk factors. Although young patients who underwent single-level fusions were at low risk, patients who underwent fusion of three or four levels had a threefold increased risk of further surgery, compared with single-level fusions (p<.0001), and a predicted 10-year prevalence of 40%.