Radiological and clinical outcomes of cervical disc arthroplasty for the elderly: a comparison with young patients.

BACKGROUND: This study aimed to investigate whether cervical disc arthroplasty (CDA) would be equally effective in elderly patients as in the young. The inclusion criteria of published clinical trials for CDA-enrolled patients covered the ages from 18 to 78 years. However, there was a paucity of data addressing the differences of outcomes between older and the younger patients. METHODS: A series of consecutive patients who underwent one- or two-level CDA were retrospectively reviewed. Patients at the two extreme ends of the age distribution (≥65 and ≤ 40 years) were selected for comparison. Clinical outcome parameters included visual analog scale (VAS) of neck and arm pain, neck disability index (NDI), and Japanese Orthopaedic Association (JOA) scores. Radiographic outcomes included range of motion (ROM) at the indexed level and evaluation of heterotopic ossification (HO) by computed tomography (CT). Complication profiles were also investigated. RESULTS: There were 24 patients in the elderly group (≥65 years old) and 47 patients in the young group (≤40 years old) with an overall mean follow-up of 28.0 ± 21.97 months. The elderly group had more two-level CDA, and thus the mean operative time was longer (239 vs. 179 min, p < 0.05) than the young group. Both groups had similarly significant improvement in clinical outcomes at the final follow-up. All the replaced disc segments remained mobile on post-operative lateral flexion and extension radiographs. However, the elderly group had a slight decrease in mean ROM (- 0.32° ± 3.93°) at the index level after CDA when compared to that of pre-operation. In contrast, the young group had an increase in mean ROM (+ 0.68° ± 3.60°). The complication profiles were not different, though a trend toward dysphagia was noted in the elderly group (p = 0.073). The incidence or severity (grading) of HO was similar between the two groups. CONCLUSIONS: During the follow-up of two years, CDA was equally effective for patients over 65 years old and those under 40 years in clinical improvement. Although the elderly group demonstrated a small reduction of mean ROM after CDA, in contrast to the young group which had a small increase, the segmental mobility was well preserved at every indexed level for each group.

Cervical Disc Arthroplasty (CDA) versus Anterior Cervical Discectomy and Fusion (ACDF) for Two-Level Cervical Disc Degenerative Disease: An Updated Systematic Review and Meta-Analysis.

Background: Anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA) are both considered to be efficacious surgical procedures for treating cervical spondylosis in patients with or without compression myelopathy. This updated systematic review and meta-analysis aimed to compare the outcomes of these procedures for the treatment of cervical degenerative disc disease (DDD) at two contiguous levels. Methods: The PubMed, EMBASE, and Cochrane CENTRAL databases were searched up to 1 May 2023. Studies comparing the outcomes between CDA and ACDF in patients with two-level cervical DDD were eligible for inclusion. Primary outcomes were surgical success rates and secondary surgery rates. Secondary outcomes were scores on the Neck Disability Index (NDI) and Visual Analogue Scale (VAS) for neck and arm pain, as well as the Japanese Orthopaedic Association (JOA) score for the severity of cervical compression myelopathy and complication rates. Results: In total, eight studies (two RCTs, four retrospective studies, and two prospective studies) with a total of 1155 patients (CDA: 598; ACDF: 557) were included. Pooled results revealed that CDA was associated with a significantly higher overall success rate (OR, 2.710, 95% CI: 1.949-3.770) and lower secondary surgery rate (OR, 0.254, 95% CI: 0.169-0.382) compared to ACDF. In addition, complication rates were significantly lower in the CDA group than in the ACDF group (OR, 0.548, 95% CI: 0.326 to 0.919). CDA was also associated with significantly greater improvements in neck pain VAS than ACDF. No significant differences were found in improvements in the arm VAS, NDI, and JOA scores between the two procedures. Conclusions: CDA may provide better postoperative outcomes for surgical success, secondary surgery, pain reduction, and postoperative complications than ACDF for treating patients with two-level cervical DDD.

Four-Level Cervical Disc Arthroplasty.

BACKGROUND: Multilevel anterior cervical discectomy and fusion inevitably yields a higher chance of pseudarthrosis or require more reoperations than single-level procedures. Therefore, multilevel cervical disc arthroplasty (CDA) could be an alternative surgery for cervical spondylosis, as it (particularly 3- and 4-level CDA) could preserve more functional motility than single-level disc diseases. This study aimed to investigate the clinical and radiological outcomes of 4-level CDA, a relatively infrequently indicated surgery. METHODS: The medical records of consecutive patients who underwent 4-level CDA were retrospectively reviewed. These highly selected patients typically had multilevel disc herniations with mild spondylosis. The inclusion criteria were symptomatic cervical spondylotic myelopathy, radiculopathy, or both, that were medically refractory. The clinical outcomes were assessed. The radiographic outcomes, including global and individual segmental range of motion (ROM) at C3-7, and any complications were also analyzed. RESULTS: Data from a total of 20 patients (mean age: 56 ± 8 years) with an average follow-up of 34 ± 20 months were analyzed. All patients reported improved clinical outcomes compared with that of preoperation, and the ROMs at C3-7 were not only preserved but also trended toward an increase (35 ± 8 vs 37 ± 10 degrees, pre- vs postoperation, P = 0.271) after the 4-level CDA. However, global cervical alignment remained unchanged. There was one permanent C5 radiculopathy, but no other neurological deteriorations or any reoperations occurred. CONCLUSION: For these rare but unique indications, 4-level CDA yielded clinical improvement and preserved segmental motility with low rates of complications. Four-level CDA is a safe and effective surgery, maintaining the ROM in patients with primarily disc herniations and mild spondylosis. CLINICAL RELEVANCE: For patients with mild spondylosis, whose degeneration at the cervical spine is not so severe, CDA is more suitable.

Prosthesis design and likelihood of achieving physiological range of motion after cervical disc arthroplasty: analysis of range of motion data from 1,173 patients from 7 IDE clinical trials.

BACKGROUND CONTEXT: The functional goals of cervical disc arthroplasty (CDA) are to restore enough range of motion (ROM) to reduce the risk of accelerated adjacent segment degeneration but limit excessive motion to maintain a biomechanically stable index segment. This motion-range is termed the "Physiological mobility range." Clinical studies report postoperative ROM averaged over all study subjects but they do not report what proportion of reconstructed segments yield ROM in the Physiological mobility range following CDA surgery. PURPOSE: To calculate the proportion of reconstructed segments that yield flexion-extension ROM (FE-ROM) in the Physiological mobility range (defined as 5°-16°) by analyzing the 24-month postoperative data reported by clinical trials of various cervical disc prostheses. STUDY DESIGN/SETTING: Analysis of 24-month postoperative FE-ROM data from clinical trials. PATIENT SAMPLE: Data from 1,173 patients from single-level disc replacement clinical trials of 7 cervical disc prostheses. OUTCOME MEASURES: 24-month postoperative index-level FE-ROM. METHODS: The FE-ROM histograms reported in Food and Drug Administration-Investigational Device Exemption (FDA-IDE) submissions and available for this analysis were used to calculate the frequencies of implanted levels with postoperative FE-ROM in the following motion-ranges: Hypomobile (0°-4°), Physiological (5°-16°), and Hypermobile (≥17°). The ROM histograms also allowed calculation of the average ROM of implanted segments in each of the 3 motion-ranges. RESULTS: Only 762 of 1,173 patients (implanted levels) yielded 24-month postCDA FE-ROM in the physiological mobility range (5°-16°). The proportions ranged from 60% to 79% across the 7 disc-prostheses, with an average of 65.0%±6.2%. Three-hundred and two (302) of 1,173 implanted levels yielded ROM in the 0°-4° range. The proportions ranged from 15% to 38% with an average of 25.7%±8.9%. One-hundred and nine (109) of 1,173 implanted levels yielded ROM of ≥17° with a range of 2%-21% and an average proportion of 9.3%±7.9%. The prosthesis with built-in stiffness due to its nucleus-annulus design yielded the highest proportion (103/131, 79%) of implanted segments in the physiological mobility range, compared to the cohort average of 65% (p<.01). Sixty-five of the 350 (18.6%) discs implanted with the 2 mobile-core designs in this cohort yielded ROM≥17° as compared to the cohort average of 9.3% (109/1,173) (p<.05). At 2-year postCDA, the "hypomobile" segments moved on average 2.4±1.2°, those in the "physiological-mobility" group moved 9.4±3.2°, and the hypermobile segments moved 19.6±2.6°. CONCLUSIONS: Prosthesis design significantly influenced the likelihood of achieving FE-ROM in the physiological mobility range, while avoiding hypomobility or hypermobility (p<.01). Postoperative ROM averaged over all study subjects provides incomplete information about the prosthesis performance - it does not tell us how many implanted segments achieve physiological mobility and how many end up with hypomobility or hypermobility. We conclude that the proportion of index levels achieving postCDA motions in the physiological mobility range (5°-16°) is a more useful outcome measure for future clinical trials.

Restoration of Range of Motion in the Cervical Spine through Single-Segment Artificial Disc Replacement Using the Baguera®C Prosthesis.

Background: Anterior cervical discectomy and fusion (ACDF) is a standard procedure for degenerative diseases of the cervical spine, providing nerve decompression and spinal stabilization. However, it limits cervical spine motility, restricts fused segment activity, and may lead to adjacent degeneration. Cervical disc arthroplasty (CDA) is an accepted alternative that preserves the structure and flexibility of the cervical spine. This study aimed to explore the dynamic changes in the range of motion (ROM) of the cervical spine after CDA using a viscoelastic artificial disc, as well as the factors affecting mobility restoration. Methods: A retrospective analysis was conducted on 132 patients who underwent single-level anterior cervical discectomy and CDA from January 2015 to June 2022. Result: Analysis of data from 132 patients revealed a significant improvement in clinical outcomes. The mean ROM of C2-C7 and functional spinal unit (FSU) segments significantly increased from 2 to 36 months post-operatively. Cervical spine flexibility was preserved and enhanced after prosthesis implantation. However, it took six months for the cervical spine motility to stabilize. In addition, sex and age were found to impact motility restoration, with female and younger patients exhibiting larger ROMs post-surgery. Additionally, CDA at the C5-C6 level resulted in the greatest increase in ROM, potentially improving overall kinematic ability. Conclusions: Single-segment artificial disc arthroplasty effectively restores the ROM in degenerative cervical spine conditions.

Perioperative outcomes of cervical disc arthroplasty: no difference between orthopaedic and neurologic surgeons.

Background: Given differences in residency training background, there has been increasing interest in characterizing differential outcomes between orthopaedic surgeons (OS) and neurosurgeons (NS) with regards to outcomes after cervical disc arthroplasty (CDA). This study aimed to assess if there were differences in perioperative outcomes of CDA between OS and NS. Methods: Patients who underwent a single-level CDA between 2012 and 2019 were identified from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database using current procedural terminology codes. The patients were subsequently stratified into those who underwent CDA with OS versus NS, and propensity score-matched to adjust for differences in patient characteristics. Differences were assessed in medical and surgical complications, as well as operative time and healthcare utilization parameters [reoperations, readmissions, and lengths-of-stay (LOS)]. Results: A total of 2,148 patients were identified (NS: n=1,395; OS: n=753). After 1:1 propensity score matching (n=741 each), there were no differences in characteristics between patients who underwent CDA by OS versus NS (P>0.05). There were no significant differences in any of the medical or surgical complications between the two groups (P>0.05 for each). There was a significant difference in the operative time between NS and OS (103.7±36.18 vs. 98.75±36.69 minutes; P=0.009). There were no significant differences in readmissions, reoperations, or LOS between the two groups (P>0.05 for each). Conclusions: There were no differences in medical or surgical complications, as well as in reoperations, readmissions, and LOS in patients who underwent a single-level CDA between OS and NS. There was a statistically significant shorter operative time of four minutes for OS as compared to NS, which is unlikely to have clinical relevance.

Single-level posterior cervical foraminotomy associated with increased incidence of early postoperative wound infection rates relative to anterior cervical discectomy with fusion and cervical disc arthroplasty.

Background: To date, there are no studies comparing perioperative outcomes of cervical radiculopathy patients managed by anterior cervical discectomy with fusion (ACDF), cervical disc arthroplasty (CDA), or posterior cervical foraminotomy (PCF). To assess if there were differences in perioperative outcomes between cervical radiculopathy patients who can be appropriately treated with ACDF, CDA, or PCF. Methods: Patients diagnosed with cervical radiculopathy who underwent a single-level ACDF, CDA, or PCF between 2012 and 2019 were retrospectively identified from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database using current procedural terminology (CPT) codes. Patients were subsequently stratified into those who underwent ACDF, CDA, or PCF, and propensity score-matched to adjust for differences in patient demographics/characteristics. Differences were assessed in terms of operative time, healthcare utilization metrics (reoperations, readmissions, lengths-of-stay), as well as medical and surgical complications. Results: A total of 18,614 cervical radiculopathy patients undergoing surgery were identified (ACDF: n=15,862; CDA: n=1,731; PCF: n=1,021). After 1:1 propensity score matching (n=535 each), there were no differences in characteristics in patients undergoing ACDF, CDA, or PCF (P>0.05). PCF patients had statistically higher rates of reoperation (2.1%) than ACDF (0.4%), CDA (0.6%) patients (P=0.010). PCF patients also experienced higher rates of superficial infection (P=0.001), and deep infection (P=0.007), relative to ACDF and CDA patients. There were no other significant differences in medical/surgical complications between the ACDF, CDA, or PCF patients. Conclusions: Cervical radiculopathy patients undergoing PCF are associated with higher rates of perioperative infection and overall reoperation than ACDF or CDA. Further research is required to elucidate the mechanism behind this association.

Short Review/Perspective on Adjacent Segment Disease (ASD) Following Cervical Fusion Versus Arthroplasty.

Background: Although the incidence of radiographic Adjacent Segment Disease (ASD) following anterior cervical diskectomy/fusion (ACDF) or cervical disc arthroplasty (CDA) typically ranges from 2-4%/year, reportedly fewer patients are symptomatic, and even fewer require secondary surgery. Methods: Multiple studies have documented a 2-4% incidence of radiographic ASD following either ACDF or CDA per year. However, fewer are symptomatic from ASD, and even fewer require additional surgery/reoperations. Results: In a meta-analysis (2016) involving 83 papers, the incidence of radiographic ASD per year was 2.79%, but symptomatic disease was present in just 1.43% of patients with only 0.24% requiring secondary surgery. In another study (2019) involving 38,149 patients undergoing ACDF, 2.9% (1092 patients; 0.62% per year) had radiographic ASD within an average of 4.66 postoperative years; the younger the patient at the index surgery, the higher the reoperation rate (i.e. < 40 years of age 4.56 X reoperations vs. <70 at 2.1 X reoperations). In a meta-analysis of 32 articles focusing on ASD 12-24 months following CDA, adjacent segment degeneration (ASDeg) occurred in 5.15% of patients, but adjacent segment disease (AS Dis) was noted in just 0.2%/ year. Further, AS degeneration occurred in 7.4% of patients after 1-level vs. 15.6% following 2 level fusions, confirming that CDA's "motion-sparing" design did not produce the "anticipated" beneficial results. Conclusion: The incidence of radiographic ASD ranges from 2-4% per year for ACDF and CDA. Additionally, both demonstrate lesser frequencies of symptomatic ASD, and the need for secondary surgery. Further, doubling the frequency of ASD following 2 vs. 1-level CDA, should prompt surgeons to limit surgery to only essential levels.

Cervical disc arthroplasty (CDA)/total disc replacement (TDR) vs. anterior cervical diskectomy/fusion (ACDF): A review.

Background: We performed a focused review to determine the "non-inferiority", potential superiority, and relative safety/efficacy for performing cervical disc arthroplasty (CDA)/total disc replacement (TDR) in carefully selected patients vs. anterior cervical diskectomy/fusion (ACDF). Notably, CDA/TDR were devised to preserve adjacent level range of motion (ROM), reduce the incidence of adjacent segment degeneration (ASD), and the need for secondary ASD surgery. Methods: We compared the incidence of ASD, reoperations for ASD, safety/efficacy, and outcomes for cervical CDA/TDR vs. ACDF. Indications, based upon the North American Spine Society (NASS) Coverage Policy Recommendations (Cervical Artificial Disc Replacement Revised 11/2015 and other studies) included the presence of radiculopathy or myelopathy/myeloradiculopathy at 1-2 levels between C3-C7 with/without neck pain. Contraindications for CDA/TDR procedures as quoted from the NASS Recommendations (i.e. cited above) included the presence of; "Infection…", "Osteoporosis and Osteopenia", "Instability…", "Sensitivity or Allergy to Implant Materials", "Severe Spondylosis…", "Severe Facet Joint Arthropathy…", "Ankylosing Spondylitis" (AS), "Rheumatoid Arthritis (RA), Previous Fracture…", "Ossification of the Posterior Longitudinal Ligament (OPLL)", and "Malignancy…". Other sources also included spinal stenosis and scoliosis. Results: Cervical CDA/TDR studies in the appropriately selected patient population showed no inferiority/ occasionally superiority, reduced the incidence of ASD/need for secondary ASD surgery, and demonstrated comparable safety/efficacy vs. ACDF. Conclusion: Cervical CDA/TDR studies performed in appropriately selected patients showed a "lack of inferiority", occasional superiority, a reduction in the incidence of ASD, and ASD reoperation rates, plus comparable safety/efficacy vs. ACDF.

Comparison of adverse events between cervical disc arthroplasty and anterior cervical discectomy and fusion: a 10-year follow-up.

BACKGROUND CONTEXT: Cervical disc arthroplasty (CDA) has been advocated as an alternative to anterior cervical discectomy and fusion (ACDF) with the added potential to reduce the risk of adjacent level disc degeneration and segmental instability. However, the long-term adverse events of arthroplasty have yet to be fully reported. PURPOSE: To investigate the 10-year follow-up adverse events rates between CDA and ACDF. STUDY DESIGN/SETTING: The study was a randomized, prospective, multicenter Investigational Device Exemption (IDE) trial and its continued follow-up as a postapproval study (PAS). Single level surgeries were performed for cervical disc pathologies between May 2002 and October 2004. PATIENT SAMPLE: n=463 patients. OUTCOME MEASURES: Adverse events comparison of CDA and ACDF from self-reported and physiologic measures. METHODS: At each evaluation time point, subjects were queried for adverse events since their last visit; and all adverse events were documented, regardless of whether or not they appeared related to the surgery or device. Adverse events were recorded, categorized, and assessed for severity and relationship to the study device and/or surgical procedure. The 10-year cumulative rates for each type of adverse events were summarized using a life-table method for the time-to-event analysis. A log-rank test was used to compare the two treatment groups. RESULTS: A total of 242 patients received CDA and 221 patients received ACDF. At 10-year follow-up, 54% (130/242) of CDA patients and 47% (104/221) of the ACDF subjects were evaluated. At up to 10-year follow-up, 231 patients in the CDA group (cumulative rate 98.4%) and 199 patients in the ACDF group (cumulative rate 98.7%) had at least one adverse event. Overall, the difference in the cumulative rate of all adverse events over 10 years was not statistically different (p=0.166). The cumulative rates of the following adverse events were not different between the two groups for cancer, cardiovascular, death, dysphonia/dysphagia, gastrointestinal, infection, urogenital, respiratory, implant displacement/loosening, implant malposition, neck and arm pain, neurological, other pain, spinal events, and intraoperative vascular injury. However, there were more adverse events in the CDA group resulting from trauma (p=.012) and more spinal events at the index level (p=.006). The ACDF group had significantly more nonunion events (p=.019), and nonunion outcome pending (p=.034), adjacent level spinal events (p=.033), and events that fell into the "other" category (p=.015). CONCLUSIONS: The cumulative rates of patients who had any adverse events were not different between the artificial cervical disc and the anterior cervical arthrodesis groups. In addition, the cumulative rates were not different between the two groups for the majority of categories as well.

Cervical disc arthroplasty versus anterior cervical discectomy and fusion: a meta-analysis of rates of adjacent-level surgery to 7-year follow-up.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) is an effective treatment for cervical spondylosis. A limitation of ACDF is the risk of adjacent-segment degeneration (ASD), owing to arthrodesis of a motion segment. Cervical disc arthroplasty (CDA) has hence garnered significant attention; yet, compelling evidence of reduction in ASD requiring surgery is lacking. This systematic review and meta-analysis sought to compare long-term longitudinal adjacent-level operation rates with CDA versus ACDF. METHODS: An electronic literature search was conducted. Eligible studies were multi-center randomized controlled trials (RCTs) comparing CDA with ACDF for one- or two-level symptomatic cervical spondylosis. The primary outcome was adjacent-level operation. Index-level reoperation was a secondary outcome. Outcomes were evaluated at 1-year intervals from the index operation to last reported follow-up by random-effects meta-analyses. RESULTS: Eleven RCTs met criteria. For one-level spondylosis, there was no difference in the rate of adjacent-level operation between CDA (2.3%) and ACDF (3.6%) at 2 years. However, a large difference favoring CDA became evident at 5 years and persisted at 7 years (4.3% vs. 10.8%, P<0.001). Significantly fewer patients who underwent CDA required index-level reoperation at all time points out to 7 years (5.2% vs. 12.7%, P<0.001). Similar to one-level operations, there was no significant difference in adjacent-level operations with two-level CDA (1.7%) versus two-level ACDF (3.4%) at 2 years. At 7 years, a significant difference favoring CDA became apparent (5.1% vs. 10.0%, P=0.014). Two-level CDA resulted in fewer index-level reoperations out to 7 years (4.2% vs. 13.5%, P<0.001). CONCLUSIONS: In this meta-analysis, the short-term rate of adjacent-level operation was similar with CDA or ACDF. However, around 5 years, a statistically significant divergence emerged, where the rate of adjacent-level surgery rose steeply for ACDF. Index-level reoperations were less frequent with CDA in both the short- and long-term. These data indicate CDA may have a superior longevity to ACDF with regard to need for subsequent adjacent-level operation.

One-Level Versus 2-Level Treatment With Cervical Disc Arthroplasty or Fusion: Outcomes Up to 7 Years.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA) have been used to treat degenerative disc disease at single as well as multiple cervical levels. This study compares the safety and efficacy of 1-level versus 2-level CDA and ACDF. METHODS: In total, 545 and 397 patients with degenerative disc disease were studied in 1-level and 2-level Food and Drug Administration (FDA)-approved clinical trials, respectively: CDA (n = 280 and 209), ACDF (n = 265 and 188). Data from these studies were used to compare 1- versus 2-level procedures: the propensity score method was used to adjust for potential confounding effects, and adjusted mean outcome safety and efficacy scores at 2 and 7 years postsurgery were compared between 1-level and 2-level procedures within treatment type. RESULTS: One-level and 2-level procedures had similar rates of improvement in overall success and patient-reported outcomes scores for both CDA and ACDF. There were no statistical differences in rates of implant-related adverse events (AEs) or serious implant-related AEs between 1-level and 2-level CDA. The 7-year rate of implant-related AEs was higher for 2-level than 1-level ACDF (27.7% vs 18.9%, P ≤ .036), though the rates of serious implant-related AEs between ACDF groups did not differ significantly. Secondary surgery rates were not statistically different between 1-level and 2-level procedures (CDA or ACDF) at the index or adjacent levels at 2 or 7 years. Grade IV heterotopic ossification at 7 years was reported in 4.6% of 1-level CDA patients and 8.6%/7.3% at the superior/inferior levels, respectively, of 2-level CDA patients. CONCLUSIONS: One- and 2-level CDA appear equally safe and effective in the treatment of cervical degenerative disc disease. Two-level ACDF appears to be as effective as 1-level ACDF but with a higher rate of some AEs at long-term follow-up. LEVEL OF EVIDENCE: 2. CLINICAL TRIALS: clinicaltrials.gov: NCT00667459, NCT00642876, and NCT00637156.

The Mobi-C® cervical disc and other devices for two-level disc replacement: overview of its safety and efficacy.

INTRODUCTION: Cervical disc arthroplasty (CDA) has become an acceptable alternative for anterior cervical discectomy and fusion (ACDF) for a significant patient population with cervical radiculopathy and/or myelopathy secondary to degenerative changes in the cervical spine. There are sufficient mid- and long-term data supporting performance and safety of one-level CDA. With the success of single-level cervical CDA, considerable interest exists about CDA use for multilevel cervical degenerative disc disease (DDD). This review analyzes the safety and efficacy of two-level CDA for treatment of symptomatic cervical DDD with focus on the Mobi-C® Cervical Disc. AREAS COVERED: This review summarizes previously published articles in a literature search using keywords: 'two-level-anterior cervical arthrodesis; two-level anterior cervical decompression and fusion (ACDF); two-level cervical disc arthroplasty (CDA); two-level cervical total disc replacement; two-level symptomatic degenerative disc disease (DDD); Mobi-C® disc'. EXPERT OPINION: Two-level CDA with the Mobi-C® device demonstrated equivalent, and in certain aspects, favorable outcomes compared to ACDF for treatment of symptomatic cervical 2-level degenerative disc disease (DDD) indicating a satisfactory safety and efficacy profile.

Trends in cervical disc arthroplasty and revisions in the Medicare database.

BACKGROUND: Due to increased postoperative complications with anterior cervical discectomy and fusion (ACDF), there has been an increasing interest in the use of cervical disc arthroplasty (CDA). Advancements in prosthetic designs and techniques have improved patient reported outcome measurements and minimized revision rates. There is a paucity in the literature regarding recent trends in CDA utilization and revision rates. The purpose of this study was to determine annual primary and revision CDA trends with the use of an administrative database. METHODS: A retrospective review from 2005-2014 was performed using the Medicare Standard Analytical Files from the PearlDiver supercomputer (PearlDiver Technologies, Fort Wayne, IN, USA). Patients who underwent primary CDA were queried using International Classification of Disease, ninth revision (ICD-9) and current procedural terminology (CPT) code 84.62 and 22856, respectively. Revision CDAs were queried using ICD-9 procedure code 84.66. Primary outcomes of this study included annual primary procedures, annual revision incidence (RI), and additional demographic data such as age, gender, geographic location, Charlson-Comorbidity Index (CCI); in addition to length of stay (LOS), cost, and reimbursement. RESULTS: The query returned 2,016 and 517 primary CDA and revision CDA procedures were performed in the Medicare database, respectively. The data showed that the CAGR of primary and revision CDA procedures to be 20.54% and 5.84% (P<0.001), respectively. RI and RB demonstrated a CAGR of -12.22% and -9.61%, respectively. Patients younger than the age of 65 represented the majority of the patients undergoing this procedure. Demographically, primary and revision CDAs were found highest in the South. CONCLUSIONS: The data demonstrates a high rate of annual growth in CDA utilization (20.54%) and revision CDA (5.84%), indicating there is an increase demand for CDA in the United States. Compared to ACDF, patients who undergo CDA have improved patient reported outcome measurements and lower rates of postoperative complications.

Review of long-term outcomes of disc arthroplasty for symptomatic single level cervical degenerative disc disease.

INTRODUCTION: Cervical disc arthroplasty (CDA) was developed as an alternative for anterior cervical discectomy and fusion (ACDF) for nerve root decompression. The rationale behind CDA was to help prevent adjacent segment degeneration which potentially may lead to additional surgery. Multiple randomized controlled trials have evaluated a myriad of disc arthroplasty devices over the past 10 years and provided data regarding clinical benefits and safety. Their long-term data, reporting results at 5-10 years, presents the opportunity to comment on the overall efficacy, safety and reported complications of these devices. This report reviews results of the Prestige, proDisc-C, Mobi-C Disc and various other arthroplasty devices and provides an overall report of the longest term available data and comparisons between devices. AREAS COVERED: This review summarizes previously published articles in a literature search using keywords: 'cervical disc arthroplasty', 'cervical total disc replacement', 'anterior cervical decompression and fusion', 'anterior cervical arthrodesis', 'symptomatic degenerative disc disease' and commercial names of devices. EXPERT COMMENTARY: CDA, with the devices reviewed, resulted in favorable outcomes in comparison to ACDF for the treatment of symptomatic cervical degenerative disc disease (DDD) taking in to account the long-term functional recovery, adverse events, development of adjacent segment degeneration and subsequent surgical interventions.

Long Term Societal Costs of Anterior Discectomy and Fusion (ACDF) versus Cervical Disc Arthroplasty (CDA) for Treatment of Cervical Radiculopathy.

BACKGROUND: Current literature suggests that anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA) have comparable clinical outcomes for the treatment of cervical radiculopathy. Given similar outcomes, an understanding of differences in long-term societal costs can help guide resource utilization. The purpose of this study was to compare the relative long-term societal costs of anterior cervical discectomy and fusion (ACDF) to cervical disc arthroplasty (CDA) for the treatment of single level cervical disc disease by considering upfront surgical costs, lost productivity, and risk of subsequent revision surgery. METHODS: We completed an economic and decision analysis using a Markov model to evaluate the long-term societal costs of ACDF and CDA in a theoretical cohort of 45-65 year old patients with single level cervical disc disease who have failed nonoperative treatment. RESULTS: The long-term societal costs for a 45-year old patient undergoing ACDF are $31,178 while long-term costs for CDA are $24,119. Long-term costs for CDA remain less expensive throughout the modeled age range of 45 to 65 years old. Sensitivity analysis demonstrated that CDA remains less expensive than ACDF as long as annual reoperation rate remains below 10.5% annually. CONCLUSIONS: Based on current data, CDA has lower long-term societal costs than ACDF for patients 45-65 years old by a substantial margin. Given reported reoperation rates of 2.5% for CDA, it is the preferred treatment for cervical radiculopathy from an economic perspective.

Should Cervical Disc Arthroplasty Be Done on Patients with Increased Intramedullary Signal Intensity on Magnetic Resonance Imaging?

OBJECTIVE: Several trials from the U.S. Food and Drug Administration have demonstrated the success of cervical disc arthroplasty (CDA) in patients with degenerative disc disease causing radiculopathy, myelopathy, or both. For patients who had increased intramedullary signal intensity (IISI) on magnetic resonance image (MRI), however, the effectiveness and safety of CDA was unclear. This study aimed to evaluate the outcomes of CDA for patients with IISI on preoperative MRI. METHODS: Consecutive patients who received 1-level CDA for symptomatic degenerative disc disease were reviewed retrospectively. Patients with IISI on preoperative T2-weighted MRI were compared to those without IISI (non-IISI). Clinical outcome parameters including visual analog scale, Neck Disability Index, Japanese Orthopedic Association (JOA), and Nurick scores were analyzed. Radiographic studies included dynamic lateral radiography and MRI. RESULTS: A total of 91 patients were analyzed (22 in the IISI group and 69 in the non-IISI group). The mean follow-up was 30.0 months. The demographic data were mostly similar between the 2 groups. All clinical outcomes, including visual analog scale, Neck Disability Index, JOA, and Nurick scores in the IISI group demonstrated significant improvement after operation. The IISI group had similar clinical outcomes to the non-IISI group, except that the JOA scores were generally worse. Follow-up MRI demonstrated significant regression of the length of IISI (P = 0.009). Both groups had preserved motion after CDA. CONCLUSIONS: Both clinical and radiological outcomes improved (the average length of IISI in the cervical spinal cord became shorter) after CDA. Therefore, CDA is a safe and effective option for patients even when there is IISI on the preoperative T2-weighted MRI.

Cervical disc arthroplasty (CDA) versus anterior cervical discectomy and fusion (ACDF) in symptomatic cervical degenerative disc diseases (CDDDs): an updated meta-analysis of prospective randomized controlled trials (RCTs).

PURPOSE: This meta-analysis of randomized controlled trials (RCTs) aims to evaluate the efficacy and safety in cervical disc arthroplasty (CDA) and anterior cervical discectomy and fusion (ACDF) for treating cervical degenerative disc diseases (CDDDs). METHODS: The authors searched RCTs in the electronic databases (Cochrane Central Register of Controlled Trials, PubMed, EMBASE, Medline, Embase, Springer Link, Web of Knowledge, OVID and Google Scholar) from their establishment to march 2016 without language restrictions. We also manually searched the reference lists of articles and reviews for possible relevant studies. Researches on CDA versus ACDF in CDDDs were selected in this meta-analysis. The quality of all studies was assessed and effective data was pooled for this meta-analysis. Outcome measurements were surgical parameters (operative time, blood loss, and length of hospital stay), clinical indexes [neck disability index (NDI), neurological success, range of motion (ROM), Visual Analogue Score (VAS)], complications [the number of adverse events, adjacent segment disease (ASD), and reoperation]. Subgroup analysis, sensitivity analysis, and publication bias assessment were also performed, respectively. The meta-analysis was performed with software revman 5.3. RESULTS: 37 articles (20 RCTs) with a total 4004 patients (2212 in the CDA and 1792 in the ACDF) met inclusion criteria. Eight types of disc prostheses were used in the included studies. Patients were followed up for at least 2 years in all the studies. No statistically significant differences were found between CDA and ACDF for blood loss [SMD -0.02; 95 % CI (-0.20, 0.17)], length of hospital stay [MD -0.06; 95 % CI (-0.19, 0.06)]. Statistical differences were found between operative time [MD 14.22; 95 % CI (6.73, 21.71)], NDI [SMD -0.27; 95 % CI (-0.43, -0.10)], neurological success [RR 1.13; 95 % CI (1.08, 1.18)], ROM [MD 6.72; 95 % CI (5.72, 7.71)], VAS of neck [SMD -0.40; 95 % CI (-0.75, -0.04)], VAS of arm [SMD -0.55; 95 % CI (-1.04, -0.06)], the rate of adverse events [RR 0.72 95 % CI (0.53, 0.96)], the rate of ASD [RR 0.62; 95 % CI (0.43, 0.88)], and reoperation [RR 0.50; 95 % CI (0.39, 0.63)]. Subgroup analysis stratified by different types of disc prostheses was also performed. CONCLUSIONS: CDA is associated with higher clinical indexes and fewer complications than ACDF, indicating that it is a safe and effective treatment for CDDDs. However, the operative time of CDA is longer than ACDF. Because of some limitations, these findings should be interpreted with caution. Additional studies are needed. Large, definitive RCTs are needed.