Cervical Degenerative Disc Disease Research Articles

Hybrid Solutions for the Surgical Treatment of Multilevel Degenerative Cervical Disk Disease.

Background In different stages of cervical degenerative disk disease, the combination of dynamic and nondynamic implants may be considered. The aim of this study was to investigate the applicability of criteria to assist decision making in these cases. Methods Thirty patients with spondylotic cervical radiculopathy and a coincidence of soft disk and hard disk herniation were surgically treated with a hybrid solution (combination of total disk replacement and cage fusion). The control group included 32 patients who underwent two-level cage fusion. Pre- and postoperative Japanese Orthopaedic Association (JOA) scores and range of motion (ROM) were compared. Results Twenty-three patients underwent two-level hybrid solution and 7 underwent three-level treatment. The most frequent solution (n = 13) was a combination of a dynamic implant at C5-C6 and a nondynamic implant at C6-C7. The mean JOA score improved from 13.9 to 15.6 points after surgery (mean deviation [MD] 1.6, 95% confidence interval [CI] 2.1 to 1.2, p < 0.001). ROM showed a slight trend to increase (MD 0.8, 95% CI -0.9 to 2.6, p = 0.193). In the control group, the mean JOA score improved from 13.3 to 15.1 points after surgery (MD 1.4, 95% CI 2.1 to 1.2, p < 0.001). The comparison of the postoperative JOA scores and recovery rates between the hybrid treatment group and the control group did not show significant differences. Conclusions In cases of coincident soft and hard degenerative cervical disk disease at adjacent levels, the combination of a disk prosthesis and a nondynamic implant is a safe and effective treatment option and an alternative to multilevel fusion.

Application of a stand-alone anchored spacer in noncontiguous anterior cervical arthrodesis with radiologic analysis of the intermediate segment

The purpose of this study was to describe the clinical features of noncontiguous cervical degenerative disc disease (cDDD), investigate the efficacy and complications of a stand-alone anchored spacer (SAAS) for patients with noncontiguous cDDD, and present radiologic analysis of the intermediate segment (IS) after skip-level fusion. Nineteen consecutive patients with noncontiguous cDDD who underwent skip-level anterior cervical discectomy and fusion (ACDF) with SAAS from January 2010 to December 2012 were enrolled in this study. Clinical outcomes were assessed preoperatively and at 24months postoperatively using the Japanese Orthopaedic Association score, Neck Disability Index, and Visual Analog Scale. Overall cervical alignment (OCA) of the cervical spine, and the range of motion (ROM), intervertebral disc height (IDH), disc signal intensity and disc protrusion of IS were measured and compared before and after surgery. Clinical outcomes significantly improved compared to preoperative scores. The OCA was corrected and maintained at 24months postoperatively compared with preoperative values (p<0.05). There were no significant differences in the ROM and IDH of the IS at each follow-up (p>0.05). However, decreased signal intensity on T2-weighted MRI was evidenced in three mobile IS at final follow-up (20.0%). Skip-level ACDF with SAAS may be an efficacious option for the treatment of noncontiguous cDDD.

Cervical Disc Arthroplasty for Degenerative Disc Disease: Two-Year Follow-Up from an International Prospective, Multicenter, Observational Study

The traditional treatment for degenerative cervical disc disease (DCDD) is neural decompression and fusion. An alternative treatment is cervical disc arthroplasty (CDA) which brings the same benefits of DCDD in addition to maintaining segmental motion, keeping the kinematics of the spine and protecting adjacent levels.

Three-level cervical disc herniation

Abstract Multilevel cervical degenerative disc disease is well known in the cervical spine pathology, with radicular syndromes or cervical myelopathy. One or two level cervical herniated disc is common in adult and multilevel cervical degenerative disc herniation is common in the elderly, with spinal stenosis, and have the same cause: the gradual degeneration of the disc. We report the case of a patient with two level cervical disc herniation (C4 – C5 and C5 – C6) treated by anterior cervical microdiscectomy both levels and fusion at C5 – C6; after five years the patient returned with left C7 radiculopathy and MRI provided the image of a left C6 – C7 disc herniation, he underwent an anterior microsurgical discectomy with rapid relief of symptoms. Three-level cervical herniated disc are rare in adults, and the anterior microdiscectomy with or without fusion solve this pathology.

WITHDRAWN: Arthroplasty versus fusion in single-level cervical degenerative disc disease.

Background There is ongoing debate about whether fusion or arthroplasty is superior in the treatment of single level cervical degenerative disc disease. Mainly because the intended advantage of arthroplasty over fusion, that is, the prevention of symptoms due to adjacent segment degeneration in the long term, is not confirmed yet. Until sufficient long‐term results become available, it is important to know whether results of one of the two treatments are superior to the other in the first one to two years. Objectives To assess the effects of arthroplasty versus fusion for radiculopathy or myelopathy, or both due to single level cervical degenerative disc disease. Search methods We searched the following databases for randomised controlled trials (RCTs): CENTRAL (The Cochrane Library 2011, Issue 2), MEDLINE, EMBASE, and EBMR. Additionally, we searched the System for Information on Grey Literature (SIGLE), subheading Biological and Medical Sciences, the US Food and Drug Administration (FDA) database on medical devices, and Clinicaltrials.gov to identify trials in progress. We also screened the reference list of all selected papers. Date of search: 25 May 2011. Selection criteria We included RCTs that directly compared any type of cervical fusion with any type of arthroplasty, with at least one year of follow‐up. Primary outcomes were arm pain, neck pain, neck‐related functional status, patient satisfaction, neurological outcome, and global health status. Secondary outcomes were the presence of (radiological) fusion, revision surgery at the treated level, secondary surgery on adjacent levels, segmental mobility of treated and adjacent levels, and work status. Data collection and analysis Study selection was performed independently by three review authors, and 'Risk of bias' assessment and data extraction were performed by two review authors. In case of missing data or insufficient information for a judgement about risk of bias, we tried to contact the study authors or the study sponsor. The data were entered into RevMan by one review author and subsequently checked by a second review author. We assessed the quality of evidence using GRADE. We analysed heterogeneity and performed sensitivity analyses for the pooled analyses. Main results We included nine studies (2400 participants), five of which had a low risk of bias. Eight of these studies were industry sponsored. The most important results showed low‐quality evidence for a small but significant difference in alleviation of arm pain at one to two years in favour of arthroplasty (mean difference (MD) ‐1.54; 95% confidence interval (CI) ‐2.86 to ‐0.22; 100‐point scale). A small study effect could not be ruled out for this outcome in the sensitivity analyses. This means that smaller studies (or small published subsets of larger studies) showed larger differences for this outcome, which may indicate publication bias. Also, moderate‐quality evidence showed a small difference in neck‐related functional status at one to two years in favour of arthroplasty (MD ‐2.79; 95% CI ‐4.73 to ‐0.85; 100‐point scale) and a small difference in neurological outcome in favour of arthroplasty (risk ratio (RR) 1.05; 95% CI 1.01 to 1.09). These two outcomes were robust to sensitivity analyses. For none of the primary outcomes, was a clinically relevant difference shown. Additionally, there was high‐quality evidence for a large, statistically significant difference in segmental mobility at one to two years (measured as degrees segmental range of motion) at the treated level (MD 6.90; 95% CI 5.45 to 8.35). There was low‐quality evidence that there was no statistically significant difference in secondary surgery at the adjacent levels at one to two years (RR 0.60; 95% CI 0.35 to 1.02). The latter was not robust to sensitivity analyses. Authors' conclusions There was a tendency for clinical results to be in favour of arthroplasty; often these were statistically significant. However, differences in effect size were invariably small and not clinically relevant for all primary outcomes. Significance was often gained or lost in the varying sensitivity analyses, probably owing to the relatively small number of studies, in combination with the small differences that were found. Given the fact that all of the included studies were not blinded, this could be due to patient or carer expectations. However, at this time both treatments can be seen as valid options with respect to results at a maximum of one to two years. Given the current absence of truly long‐term results, use of these mobile disc prostheses should still be limited to clinical trials. There was high‐quality evidence that the goal of preservation of segmental mobility in arthroplasty was met. A statistically significant effect on the incidence of secondary symptoms at adjacent levels, the primary goal of arthroplasty over fusion, was not found at one to two years. If there was a protective effect, this should become clearer over time. A future update, when studies with 'truly long‐term' results (five years or more) become available, should focus on this issue.

Multilevel Anterior Cervical Discectomies and Cage-Augmented Fusion without Plate Fixation

Objective The number of surgical techniques of decompression and solid interbody fusion as a treatment for cervical degenerative disc disease (DDD) has increased rapidly. Cage-assisted anterior cervical discectomy and fusion (ACDF) has proven to be a safe and effective procedure for one and two-level DDD. Multilevel cervical discectomy usually requires plate and screw fixation for maintaining the spinal curvature and increasing the graft fusion rate. Clinical results after three or four-level interbody cage-augmented ACDF have been reported in very few literatures. We investigated the safety and effectiveness of cages used in such procedures without plate fixation and evaluated the results. Methods Forty-five patients suffering from three or four-level cervical DDD underwent cage (PEEK or titanium)-assisted ACDF without plate fixation. The cervical DDD was confirmed by radiography and magnetic resonance imaging. The patients underwent radiographic evaluation to assess cervical lordosis, segmental height of cervical spine, foraminal height, cross-sectional area of foramina, the angle between the two adjacent endplates, and spinal stability. Neurological outcomes were assessed using the Prolo scale. Neck pain was assessed using the visual analogue scale (VAS). The follow-up period ranged from 27 to 53 months (mean, 35 months). Results A significant improvement ( p &lt; 0.001) in the Prolo scale scores (preoperatively 7.9 ± 1.7 and postoperatively 8.7 ± 1.1) and VAS pain scores (preoperatively 8.8 ± 1 and postoperatively 3 ± 1.5) was demonstrated. A significant increase in cervical lordosis, segmental height, foraminal height, cross-sectional area of foramina, and angle between the two adjacent endplates was noted. Good stability was obtained in all patients 12 months postoperatively and the complication rate was 0%. Conclusion Multilevel (3 or 4) anterior cervical discectomies and cage (PEEK or titanium)-augmented interbody fusion without plating is a good method for management of multilevel cervical DDD. It provides long-term stabilization, increases lordosis, segmental and foraminal height, and cross-sectional area of foramina. Satisfactory neurological outcomes can be obtained and donor site complication can be avoided.

Multilevel Cervical Arthroplasty versus Multilevel Fusion in Three-Level Cervical Disc Disease (Clinical and Radiological Outcomes)

Introduction The surgical treatment for cervical disc disease increased in the last decade using different surgical techniques. The percentage of the patients being surgically treated for three-level cervical disc disease remains small therefore the optimal surgical approach for these patients remains the subject of discussion. Multiple cervical disc arthroplasty, multilevel fusion, and hybrid procedures are among the options using the anterior approach. The aim of the study was to compare the multilevel cervical disc arthroplasty and multilevel fusion and compare clinical as well as the radiographic results in patients treated for three-level symptomatic cervical degenerative disc disease 2 years after the surgery. Methods Overall, 23 patients with three-level symptomatic cervical degenerative disc disease were treated with complete anterior cervical discectomy and either with ProDisc-C disc arthroplasty or with fusion using Cervios chronoOS prostheses (ACDF) or standalone cervical cages. Overall 8 multilevel arthroplasty and 14 ACDF's procedures were performed. Clinical outcomes were assessed before and 12 and 24 months after the procedure using neurological examination, the neck disability index (NDI) and visual analogue scale (VAS) for neck and arm pain, with 15% improvement in NDI and 20% in VAS defined as clinically significant. Comparison between both groups (arthroplasty and fusion group) was based on clinical outcomes using neurological examination, VAS, NDI, and patient's satisfaction. Preoperative and postoperative ROMs (range of motion) were evaluated by measuring the lateral and flexion–extension radiographs. Results Both groups had a statistically significant improvement in NDI and VAS for neck and arm pain ( p &lt; 0.05), 2 years after the surgery and the arthroplasty group had a slightly better improvement according to NDI (71.4% of patients in the arthroplasty group achieved ≥ 15% improvement in NDI and 67.5 of patients in ACDF group). The arthroplasty group showed faster recovery of C2 to C7 range of motion. There was a statistically significant difference in the C2 to C7 ROM between the two groups at 12 and 24 months postoperatively ( p &lt; 0.05). The ROM of the arthroplasty group approached the preoperative value at 12 months however it decreased again at 24 months. Conclusions Disc arthroplasty can be an effective alternative in the surgical treatment for the multilevel cervical disc disease, preserving segmental motion after surgery and providing improvement in pain and functional outcome for the patients. The right surgical treatment for the three-level disc disease remains the subject of discussion and more long-term follow-up studies will be needed to determine the definitive treatment.

A Retrospective Clinical and Fusion Analysis of the STALIF-C Device with Stem Cell Derivative Bone Graft Material

Introduction Perform a retrospective review of a single site experience with the STALIF-C (Centinel Spine) integrated cervical fusion device and OsteoCel + stem cell–derived allograft material (NuVasive, Inc.). Material and Methods We reviewed all charts of patients undergoing an anterior cervical discectomy and fusion (ACDF one, two, and three levels), utilizing the STALIF-C device and Osteocel + bone graft material. Data comprised patients from January 2012 to April 2014, with an average final imaging follow-up of 5 months. All patients underwent the ACDF by the same surgeon at the same institution. Fusion criteria were assessed primarily by thin cut CT scans with multimodal reconstructions, but also with dynamic X-rays if CT imaging was unavailable. We implemented a standardized CT fusion criteria, for which all images were read by an independent Board Certified Neuroradiologist. Criteria for fusion was based on a grade 1 to 5 scale (CT imaging), and/or no movement on dynamic X-rays of greater than 2 degrees. Results A total of 101 patients were included in the study, with imaging and clinical follow-up obtained in 101 patients (100%). There were 39 males and 62 females, with an average age of 54. The break down in the number of levels treated was as follows: One level (49%), two levels (36%), and three levels (15%). Overall, 14% of the patients were active smokers, 11% had a history of former nicotine abuse, and 74% were nonsmokers. All the follow-up fusion assessments were done with thin cut CT scans with sagittal and coronal reconstructions, and dynamic X-rays. The fusion rates for the levels treated were as follows: one level (98%), two levels (94%), and three levels (87%). The integrated fusion rate was 95% without separating the procedures by levels. There were no incidents of hardware failure or break, with only one patient requiring a posterior cervical fusion for symptomatic pseudoarthrosis (multilevel fusion patient). Conclusion The STALIF-C integrated cervical fusion device, in conjunction with Osteocel + stem cell–derived bone graft material is a safe, effective, and reproducible fusion construct in the treatment of cervical degenerative disc disease. The rates of fusion, as compared with systematic meta-analyses in the literature, are comparable and in some cases superior to reported rates using standard cervical plating and cage constructs. To the best of our knowledge, this is the largest review analysis of any integrated cervical fusion device.

Combination of Fusion and Motion Preservation in the Surgical Treatment of Degenerative Cervical Disc Disease

Introduction Our clinical study design was prospective, concurrently enrolled, and single-center trial of the combination of fusion (intervertebral cage with or without ventrofixation) and cervical disc prosthesis implantation in the treatment of patients with multiple level degenerative disc disease. The cervical disc arthroplasty become more and more popular in the surgical treatment of the degenerative cervical disc disease. The goals of the cervical disc arthroplasty are to maintain or restore intervertebral height, spinal balance and mobility, and to avoid adjacent segment degeneration. However, in most of the patients with multisegmental degenerative disc disease, the certain segments show different stage of degeneration and instability. The study was designed to investigate the clinical effects of the combination of cervical fusion and arthroplasty and to observe the stability, range of motion, and the cervical spine sagittal balance in the follow-up period. Patients and Methods Since December 2007 to September 2012, 36 patients with symptomatic cervical radiculopathy and/or myelopathy underwent surgery with this combined method. In 14 cases, the surgery involved two level, in 16 cases was three level, and 6 cases was four level. At the follow-up period, the patients' pain, neurologic function, and the radiographic parameters (range of motion at the level of prosthesis and the adjacent segments, the intervertebral disc height of the adjacent segments, lordosis of the whole cervical spine, and heterotopic ossification) were evaluated. Results Early clinical experiences are promising. The segment of the prosthesis ultimately showed preservation of motion when compared with preoperative levels. The pre-op average ROM was 8.2 degrees (flexion/extension), the post-op average ROM 7.6 degrees. The whole cervical spine lordosis was pre-op 1.7 degrees the post-op 16.2 degrees. We have no implant-related failure. Conclusion The most important potential advantages of this method is that we can treat the multisegmental degeneration in each segment with the proper method including motion preservation and fusion, and restore the sagittal balance of the cervical spine. Although early results are promising, long-term follow-up studies required to prove its efficacy in the surgical treatment of the multisegmental degenerative cases.

Evaluation of Subsidence in Stand-Alone Cervical Cage: Incidence, Risk Factors and Effects on Clinical and Radiological Picture

Background Data: Anterior Cervical Discectomy and Fusion is the gold standard for treating cervical degenerative disc disease associated with radiculopathy and/or myelopathy. When indicated, surgery can achieve neural tissuedecompression and biomechanical stabilization through bony fusion. One of the known complications of stand-alone anterior cervical cage is cage subsidence. Published literature however, contains mixed results in terms of rate of cagesubsidence, loss of lordosis and its clinical effects. Purpose: We report our experience in stand-alone anterior cervical cage, our subsidence rate and its effect on loss of lordosis and clinical picture Study Design: Retrospective clinical case study. Patients and Methods: we inserted seventy-two cervical cages (in fifty patients), who had Anterior Cervical Discectomy and Fusion using a stand-alone polyetheretherketone (PEEK) cage under our care. We recorded the self-reported Visual Analogue Score for arm and neck pain and measured the total intervertebral height/disc space or cage ratio, segmental Cobb angle, the distance between the anterior rim of the cage and the anterior vertebral body line, superior or inferior end plate violation and anterior or posterior cage migration on lateral X ray film preoperatively and on each follow up visit (day 1, 7-21 days, 3, and 6 months). Results: Our cage subsidence rate in the studied sample was 23.6% in 6 months (17 out of 62 cages subsided). We found a statistically significant correlation between immediate postoperative disc height and subsidence (the more distraction we applied to the disc space the more likely subsidence would happen). Cage subsidence did not increase the incidence of recurrence of radicular, myelopathic symptoms or neck pain although it resulted in significant loss of the segmental Cobb angle. Conclusions: Disc space over-distraction in stand-alone anterior cervical cage significantly increases the risk of subsidence. Subsidence significantly affects thesegmental Cobb angle but not the clinical outcome. (2015ESJ077)

Early clinical and radiographical results of keel-less and shallow keel cervical disc replacement.

Background:Cervical disc replacements has been shown to be as effective as fusions in the treatment of radiculopathy or myelopathy due to disc prolapse. Newer implants were designed to reduce the difficulty of end-plate preparation. Since 2010, the authors have started using Discocerv (Alphatec Spine, Carlsbad, USA) a keel-less implant and Activ-C (B. Braun, Sheffield, UK), a shallow keel implant.Aim:The aim of this study was to compare the duration of surgery between cervical disc replacement and anterior cervical discectomy and fusion, and also to evaluate the functional outcome, complications, and radiographic outcome of cervical disc replacement.Results:Fifty patients were included (20 disc replacement and 30 fusion). This was a single surgeon retrospective study, with all surgery performed by the senior author (RT). The mean operation duration for single-level disc replacement was 2.6 h, and for single-level fusion was 2.4 h (P = 0.4684). For 2-levels surgery, the result was 3.5 h for 2-level hybrid surgery (one level disc replacement and one level fusion) and 3.4 h for fusion (P = 0.4489). Disc replacement resulted in preservation of an average of 67% of the angle of motion at the sagittal plane (FFflexion-extension). The average range of motion after disc replacement was 6.1°. The median clinical follow-up duration was 2 years (average 1.8 years). There was no incidence of major complications or significant neurovascular injury in this series of patients. A significant improvement in short form-36 scores was seen as early as 3 months postoperative (from 58 preoperative to 92 at 3 months). The improvement was sustained up to the fourth year of follow-up.Conclusion:Cervical arthroplasty with keel-less and shallow keel implants are safe and relatively easy to perform. The surgical time for disc replacement is not significantly longer than standard fusion surgery. There is reasonably good preservation of motion. The short-term functional improvement is good, and we await further long-term outcome results. The authors felt that cervical disc replacement will have an important role in the treatment of cervical degenerative disc disease in the future.

Cervical spine kinematics after anterior cervical discectomy with or without implantation of a mobile cervical disc prosthesis; an RCT.

BackgroundWhen surgically treating cervical degenerative disc disease, the most commonly performed procedure is anterior cervical discectomy. This procedure is performed with, or without fusion promoting methods. For both options the rate of fusion is high and there is much debate whether fusion of the treated segment is a contributing factor to accelerated degeneration of adjacent motion segments. In an effort to prevent degeneration of adjacent segments (ASDeg) due to loss of mobility at the operated level, cervical disc arthroplasty (CDA) was introduced. To evaluate the effectiveness of CDA in preventing ASDeg long term studies are necessary. However, prevention of ASDeg is based on the premise that mobile disc prostheses preserve cervical spine motion in a physiological way. In this article the authors describe a short term protocol for a study that aims to investigate whether CDA reaches the intended goal: restoration or preservation of physiological cervical spine motion. To this end, a technique is used to establish the sequence of contributions of cervical motion segments to flexion/extension of the spine.Methods24 subjects between 18 and 55 years old, with radicular symptoms due to a herniated disc between C5 and C7, refractory to conservative therapy are randomized to simple discectomy, or CDA. These groups are preceded by a pilot group of three subjects receiving CDA. Fluoroscopic flexion-extension recordings are acquired preoperatively, and at three and 12 months postoperative. At these same time points, patient reported outcomes are collected, and a neurological examination is performed by and independent physician.DiscussionStudies investigating arthroplasty determine mobility by measuring segmental range of motion (sROM), which gives no information other than presence, and quantity, of mobility. SROM suffer from high variability. The authors therefore chose to use a method previously used in healthy controls, to describe the dynamic process of cervical spine motion in more detail. Determining cervical spine motion patterns has been reported to be more consistent than sROM. If a physiological motion pattern is absent after surgery in the CDA group, prevention of future ASDeg is less likely. Radiological outcomes will be correlated to clinical outcomes.Trial RegistrationNCT00868335Electronic supplementary materialThe online version of this article (doi:10.1186/s12891-015-0479-4) contains supplementary material, which is available to authorized users.

Assessment of Magnetic Resonance Imaging Artifact Following Cervical Total Disc Arthroplasty.

Cervical disc arthroplasty has become a technique for the treatment of cervical degenerative disc disease. Clinically, the need to accurately assess the neural elements at the operative and adjacent levels is critical postoperatively. The purpose of this study was to quantitatively and qualitatively measure the amount of MRI artifact produced by various cervical total disc replacements. T1 and T2-weighted turbo spin-echo MRI sequences were collected on the cervical spine (C2-T1) of a 68 year-old unembalmed male cadaver. A discectomy was performed at C5-6, followed by successive implantation of six different total disc replacements. The scans were quantitatively evaluated by three of the authors. The volume of artifact was measured using image analysis software. Qualitative analysis of the adjacent and index neural elements was performed. The artifact in the T2 weighted images was noted to be 58.6±7.3 cm3 for Prestige ST, 14.2±1.3 cm3 for ProDisc-C, 7.5±0.8 cm3 for Discover, 8.0±0.3 cm3 for Prestige LP, 6.6±0.7 cm3 for Bryan, and 7.3±0.6 cm3 for ProDisc-C titanium prototype. Acceptable intraobserver and excellent interobsever correlation was demonstrated using Pearson Correlation and Concordance Correlation Coefficient analysis. The adjacent and implanted level neural elements (spinal cord and neuroforamina) were easily visualized on the T2 weighted images after the implantation of titanium devices (ProDisc-C titanium prototype, Discover, Prestige LP and Bryan). After implantation of a cobalt chrome implant (ProDisc-C), the adjacent level neural elements were easily visualized but the implanted level could not be fully visualized due to distortion of the images. The quality of the distortion was least favorable after the implantation of the stainless steel implant (Prestige ST), where neither the adjacent nor the index level could be fully visualized. The volume of the artifact seen following cervical total disc arthroplasty is highly dependent upon the material property of the implant. Quantitative analysis described in this study demonstrated sufficiently low intraobserver and interobserver variability to be considered a reliable technique.

Optimal screw orientation for the fixation of cervical degenerative disc disease using nonlinear C3-T2 multi-level spinal models and neuro-genetic algorithms.

Anterior cervical discectomy and fusion is a common surgical procedure performed to remove a degenerative or herniated disc in cervical spine. Unfortunately, clinical complications of anterior cervical plate (ACP) systems still occur, such as weak fixation stability and implant loosening. Previous researchers have attempted to ameliorate these complications by varying screw orientations, but the screw orientations are mainly determined according to the investigator's experiences. Thus, the aim of this study was to discover the optimal screw orientations of ACP systems to achieve acceptable fixation stability using finite element simulations and engineering algorithms. Three-dimensional finite element models of C3-T2 multi-level segments with an ACP system were first developed to analyze the fixation stability using ANSYS Workbench 14.5. Then, artificial neural networks were applied to create one objective function, and the optimal screw orientations of an ACP system were discovered by genetic algorithms. Finally, the numerical models and the optimization study were validated using biomechanical tests. The results showed that the optimal design of the ACP system had highest fixation stability compared with other ACP designs. The neuro-genetic algorithm has effectively reduced the time and effort required for discovering for the optimal screw orientations of an ACP system. The optimum screw orientation of the ACP system could be successfully discovered, and it revealed excellent fixation stability for the treatment of cervical degenerative disc disease. This study could directly provide the biomechanical rationale and surgical suggestion to orthopedic surgeons.

Adjacent segment degeneration after single-level anterior cervical decompression and fusion: Disc space distraction and its impact on clinical outcomes

The purpose of this study was to find whether excessive distraction of the disc space for cage insertion was a risk factor for adjacent segment degeneration (ASD) after anterior cervical decompression and fusion (ACDF). One hundred and sixteen consecutive patients who underwent ACDF for single-level cervical disc herniation between June 2006 and November 2008 were retrospectively reviewed. Preoperative, postoperative and final follow-up disc height (DH), sagittal segmental alignment (SSA), and sagittal alignment of the cervical spine (SACS) were measured and compared between the ASD group and non-ASD group. In 116 patients, ASD was radiographically proven in 28 (24.1%) patients. The clinical outcomes were significantly improved compared to the preoperative scores in both groups. However, the postoperative and final follow-up DH of the ASD group were significantly higher than in the non-ASD group (p<0.05). In addition, the postoperative DH was significantly correlated with the postoperative or final follow-up SSA (p<0.05). However, postoperative DH was not found to significantly correlate with postoperative or final follow-up SACS (p=0.072 and p=0.096, respectively). Multivariate analysis showed that postoperative DH was the most significant risk factor for ASD. The clinical outcomes of ACDF for single-level degenerative cervical disc disease were satisfactory. Postoperative DH (the distracted distance) had the greatest impact on the incidence of ASD. Excessive disc space distraction is a considerable risk factor for the development of radiographic ASD.

Incidence of adjacent segment degeneration in cervical disc arthroplasty versus anterior cervical decompression and fusion meta-analysis of prospective studies.

PurposeTo evaluate the incidence of adjacent segment disease (ASD) requiring surgical intervention between anterior cervical decompression and fusion (ACDF) and total disc replacement (TDR).BackgroundThe concern for ASD has led to the development of motion-preserving technologies such as TDR. However, whether replacement arthroplasty in the spine achieves its primary patient-centered objective of lowering the frequency of adjacent segment degeneration is not verified yet.MethodsA comprehensive literature search was performed using PubMed, Cochrane Central Register of Controlled Trials and Embase. These databases were thoroughly searched for prospective randomized studies comparing ACDF and TDR. Eight studies met the inclusion criteria for a meta-analysis and were used to report an overall rate of ASD for both ACDF and TDR.ResultsPooling data from 8 prospective studies, the overall sample size at baseline was 1,726 patients (889 in the TDR group and 837 in the ACDF group). The ACDF group had significantly more ASDs compared with the TDR group at 24 months postoperatively [odds ratios (OR), 1.31; 95 % confidence interval (CI), 1.04–1.64; p = 0.02]. The TDR group had significantly fewer adjacent segment reoperations compared with the ACDF group at 24 months postoperatively (OR, 0.49; 95 % CI, 0.25–0.96; p = 0.04).ConclusionsFor patients with one-level cervical degenerative disc disease (CDDD), total disc replacement was found to have significantly fewer ASDs and reoperations compared with the ACDF. Cervical replacement arthroplasty may be superior to ACDF in ASD. Therefore, cervical arthroplasty is a safe and effective surgical procedure for treating CDDD. We suggest adopting TDR on a large scale.

The Mobi-C cervical disc for one-level and two-level cervical disc replacement: a review of the literature.

BackgroundCervical disc arthroplasty (CDA) is a novel motion-preserving procedure that is an alternative to fusion. The Mobi-C disc prosthesis, one of many Food and Drug Administration (FDA)-approved devices for CDA, is the only FDA-approved prosthesis for two-level CDA. Hence, it may allow for improved outcomes compared with multilevel fusion procedures.PurposeTo critically assess the available literature on CDA with the Mobi-C prosthesis, with a focus on two-level CDA.MethodsAll clinical articles involving the Mobi-C disc prosthesis for CDA through September 1, 2014 were identified on Medline. Any paper that presented Mobi-C CDA clinical results was included. Study design, sample size, length of follow-up, use of statistical analysis, quality of life outcome scores, conflict of interest, and complications were recorded.ResultsFifteen studies were included that investigated Mobi-C CDA, only one of which was a level Ib randomized control trial. All studies included showed non-inferiority of one-level Mobi-C CDA to one-level anterior cervical discectomy and fusion (ACDF). Only one study analyzed outcomes of one-level versus two-level Mobi-C CDA, and only one study analyzed two-level Mobi-C CDA versus two-level ACDF. In comparison with other cervical disc prostheses, the Mobi-C prosthesis is associated with higher rates of heterotopic ossification (HO). Studies with conflicts of interest reported lower rates of HO. Adjacent segment degeneration or disease, along with other complications, were not assessed in most studies.ConclusionOne-level Mobi-C CDA is non-inferior, but not superior, to one-level ACDF for patients with cervical degenerative disc disease. The Mobi-C CDA procedure is associated with high rates of HO. Two-level Mobi-C CDA may be superior to two-level ACDF. However, insufficient evidence exists, thereby mandating a need for unbiased, well-designed prospective studies with well-defined outcomes in the future.

The application of zero-profile anchored spacer in anterior cervical discectomy and fusion

We aimed to analyze the clinical efficacy of the zero-profile anchored spacers in the treatment of one-level or two-level cervical degenerative disc disease. From April 2011 to April 2013, a total of 63 consecutive patients with cervical degenerative disc disease who underwent one- or two-level ACDF using either the zero-profile anchored spacer or the stand-alone cages and a titanium plate fixation were reviewed for the radiological and clinical outcomes and complications. The zero-profile anchored spacers were used in 30 patients (anchored group) and stand-alone cages with an anterior cervical plate were implanted in 33 cases (non-anchored group). Operative time, intraoperative blood loss, clinical and radiological results were compared between the anchored group and the non-anchored group. All patients were followed up for at least 12 months. There were not bolt loosening or rupture of anchoring clips, screws or titanium plates observed in two groups during follow-up period. There were no significant difference in neck disability index scores, Japanese Orthopedic Association scores, fusion rate, and cervical lordosis during follow-up between two groups (P > 0.05), but significant difference in the operation time, blood loss and the presence of dysphagia were found (P < 0.05). There were no adjacent disc degeneration and instability observed in two groups. The zero-profile anchored spacer achieved similar clinical outcomes compared to ACDF with anterior plating for the treatment of the cervical degenerative disc disease. However, zero-profile anchored spacer was associated with a lower risk of postoperative dysphagia, shorter operation time, less blood loss, and relatively greater simplicity than the stand-alone cage with a titanium plate.

Cervical degenerative disease: systematic review of economic analyses.

Systematic review. To perform an evidence-based synthesis of the literature assessing the cost-effectiveness of surgery for patients with symptomatic cervical degenerative disc disease (DDD). Cervical DDD is a common cause of clinical syndromes such as neck pain, cervical radiculopathy, and myelopathy. The appropriate surgical intervention(s) for a given problem is controversial, especially with regard to quality-of-life outcomes, complications, and costs. Although there have been many studies comparing outcomes and complications, relatively few have compared costs and, more importantly, cost-effectiveness of the interventions. We conducted a systematic search in PubMed/MEDLINE, EMBASE, the Cochrane Collaboration Library, the Cost-Effectiveness Analysis registry database, and the National Health Service Economic Evaluation Database for full economic evaluations published through January 16, 2014. Identification of full economic evaluations that were explicitly designed to evaluate and synthesize the costs and consequences of surgical procedures or surgical intervention with nonsurgical management in patients with cervical DDD were considered for inclusion, based on 4 key questions. Five studies were included, each specific to 1 or more of our focus questions. Two studies suggested that cervical disc replacement may be more cost-effective compared with anterior cervical discectomy and fusion. Two studies comparing anterior with posterior surgical procedures for cervical spondylotic myelopathy suggested that anterior surgery was more cost-effective than posterior surgery. One study suggested that posterior cervical foraminotomy had a greater net economic benefit than anterior cervical discectomy and fusion in a military population with unilateral cervical radiculopathy. No studies assessed the cost-effectiveness of surgical intervention compared with nonoperative treatment of cervical myelopathy or radiculopathy, although it is acknowledged that existing studies demonstrate the cost-effectiveness of surgical intervention for these 2 clinical entities. A paucity of high-quality economic literature exists regarding cost-effectiveness of surgical intervention for cervical DDD. Future research is necessary to validate the findings of the few studies that do exist to guide decisions for surgery by the physician and patient with respect to cost-effectiveness. 2.

Result of the arc of movement of lower cervical spine after seven years of arthroplasty

OBJECTIVE: To quantify the mobility of the lower cervical spine after seven years of total cervical disc replacement at two levels. METHOD: This clinical study was designed randomly and prospectively at the spine surgery center at the Hospital Nossa Senhora das Graças, in Canoas, RS-Brazil and at the Hospital Don João Becker, in Gravataí, RS-Brazil. Seventeen patients were included in the study that was designed to compare the data obtained from annual and sequential manner until the end of seven years. A comparison was made with the prior range of motion (ROM) of each patient. All patients were diagnosed with not tractable symptomatic cervical degenerative disc disease with two adjacent levels between C-3 and C-7. RESULTS: A total of patients underwent TDR in two levels and at the end of seven years, only one patient was lost to follow-up. The pre and postoperative ROM was the same in the first three years however after the fourth year there was a gradual decline with a loss of 12% of preoperative ROM in flexion, 21% in extension and 23% in the right and left lateral bending at the end of seven years. CONCLUSIONS: The clinical outcome of this study is evidence level IV in evaluating the ROM for Moby-C(r) for TDR in two adjacent levels at the lower cervical spine. These results show that the ROM is maintained during the first three years, gradually declining after that.