Arthroplasty versus fusion in single-level cervical degenerative disc disease: a Cochrane review

A randomized controlled trial with extended long-term follow-up: Quality of cervical spine motion after anterior cervical discectomy (ACD) or anterior cervical discectomy with arthroplasty (ACDA)

Introduction

In previous research, a consistent sequence of segmental contributions during dynamic extension X-rays of the cervical spine was observed in 80-90% of healthy participants.

Research question

To investigate whether this previously defined 'normal' sequence of segmental contributions was present in patients who underwent anterior cervical discectomy with arthroplasty (ACDA) or anterior cervical discectomy (ACD).

Materials & methods

A randomized controlled trial with extended follow-up was conducted. Patients with single level cervical degenerative radiculopathy with a surgical indication were included and randomized. Dynamic X-ray recordings were made before surgery, one-year post-operative, and at long term follow-up.

Results

A total of 27 patients were included, three in an ACDA pilot group and 24 were randomized to receive ACDA (N = 12) or ACD (N = 12). A total of 20 patients were available for follow-up. Preoperatively, 16.7% of patients in the ACDA group and 58.3% of patients in the ACD group showed a normal sequence. One-year post-operative, 66.7% showed a normal sequence in the ACDA group versus 30.0% in the ACD group (p = 0.036). After an average of 11-years follow-up, a normal sequence was observed in 9.1% of patients in the ACDA group and in none of the patients in the ACD group (p = 0.588).

Discussion & conclusion

These findings suggest that while ACDA can restore and preserve a normal sequence of segmental contributions in the short term, this effect is not maintained in the long term. Throughout the process of ageing, not only the quantity, but also the quality of motion changes.

Biomechanical evaluation of a novel biomimetic artificial intervertebral disc in canine cervical cadaveric spines

Background Context

Cervical disc replacement (CDR) aims to restore motion of the treated level to reduce the risk of adjacent segment disease (ASD) compared with spinal fusion. However, first-generation articulating devices are unable to mimic the complex deformation kinematics of a natural disc. Thus, a biomimetic artificial intervertebral CDR (bioAID), containing a hydroxyethylmethacrylate (HEMA)-sodium methacrylate (NaMA) hydrogel core representing the nucleus pulposus, an ultra-high-molecular-weight-polyethylene fiber jacket as annulus fibrosus, and titanium endplates with pins for primary mechanical fixation, was developed.

Purpose

To assess the initial biomechanical effect of the bioAID on the kinematic behavior of the canine spine, an ex vivo biomechanical study in 6-degrees-of-freedom was performed.

Study Design

A canine cadaveric biomechanical study.

Methods

Six cadaveric canine specimens (C3-C6) were tested in flexion-extension (FE), lateral bending (LB) axial rotation (AR) using a spine tester in three conditions: intact, after C4-C5 disc replacement with bioAID, and after C4-C5 interbody fusion. A hybrid protocol was used where first the intact spines were subjected to a pure moment of ±1 Nm, whereafter the treated spines were subjected to the full range of motion (ROM) of the intact condition. 3D segmental motions at all levels were measured while recording the reaction torsion. Biomechanical parameters studied included ROM, neutral zone (NZ), and intradiscal pressure (IDP) at the adjacent cranial level (C3-C4).

Results

The bioAID retained the sigmoid shape of the moment-rotation curves with a NZ similar to the intact condition in LB and FE. Additionally, the normalized ROMs at the bioAID-treated level were statistically equivalent to intact during FE and AR while slightly decreased in LB. At the two adjacent levels, ROMs showed similar values for the intact compared to the bioAID for FE and AR and an increase in LB. In contrast, levels adjacent to the fused segment showed an increased motion in FE and LB as compensation for the loss of motion at the treated level. The IDP at the adjacent C3-C4 level after implantation of bioAID was close to intact values. After fusion, increased IDP was found compared with intact but did not reach statistical significance.

Conclusion

This study indicates that the bioAID can mimic the kinematic behavior of the replaced intervertebral disc and preserves that for the adjacent levels better than fusion. As a result, CDR using the novel bioAID is a promising alternative treatment for replacing severely degenerated intervertebral discs.

Comparison of anterior cervical discectomy and fusion versus artificial disc replacement for cervical spondylotic myelopathy: a meta-analysis

OBJECTIVE

Anterior cervical discectomy and fusion (ACDF) has long been regarded as a gold standard in the treatment of cervical myelopathy. Subsequently, cervical artificial disc replacement (c-ADR) was developed and provides the advantage of motion preservation at the level of the intervertebral disc surgical site, which may also reduce stress at adjacent levels. The goal of this study was to compare clinical and functional outcomes in patients undergoing ACDF with those in patients undergoing c-ADR for cervical spondylotic myelopathy (CSM).

METHODS

A systematic literature review and meta-analysis were performed using the Embase, PubMed, and Cochrane Central Register of Controlled Trials databases from database inception to November 21, 2021. The authors compared Neck Disability Index (NDI), SF-36, and Japanese Orthopaedic Association (JOA) scores; complication rates; and reoperation rates for these two surgical procedures in CSM patients. The Mantel-Haenszel method and variance-weighted means were used to analyze outcomes after identifying articles that met study inclusion criteria.

RESULTS

More surgical time was consumed in the c-ADR surgery (p = 0.04). Shorter hospital stays were noted in patients who had undergone c-ADR (p = 0.04). Patients who had undergone c-ADR tended to have better NDI scores (p = 0.02) and SF-36 scores (p = 0.001). Comparable outcomes in terms of JOA scores (p = 0.24) and neurological success rate (p = 0.12) were noted after the surgery. There was no significant between-group difference in the overall complication rates (c-ADR: 18% vs ACDF: 25%, p = 0.17). However, patients in the ACDF group had a higher reoperation rate than patients in the c-ADR group (4.6% vs 1.5%, p = 0.02).

CONCLUSIONS

At the midterm follow-up after treatment of CSM, better functional outcomes as reflected by NDI and SF-36 scores were noted in the c-ADR group than those in the ACDF group. c-ADR had the advantage of retaining range of motion at the level of the intervertebral disc surgical site without causing more complications. A large sample size with long-term follow-up studies may be required to confirm these findings in the future.

Research protocol: Cervical Arthroplasty Cost Effectiveness Study (CACES): economic evaluation of anterior cervical discectomy with arthroplasty (ACDA) versus anterior cervical discectomy with fusion (ACDF) in the surgical treatment of cervical degenerative disc disease - a randomized controlled trial

Introduction

To date, there is no consensus on which anterior surgical technique is more cost-effective in treating cervical degenerative disc disease (CDDD). The most commonly used surgical treatment for patients with single- or multi-level symptomatic CDDD is anterior cervical discectomy with fusion (ACDF). However, new complaints of radiculopathy and/or myelopathy commonly develop at adjacent levels, also known as clinical adjacent segment pathology (CASP). The extent to which kinematics, surgery-induced fusion, natural history, and progression of disease play a role in the development of CASP remains unclear. Anterior cervical discectomy with arthroplasty (ACDA) is another treatment option that is thought to reduce the incidence of CASP by preserving motion in the operated segment. While ACDA is often discouraged, as the implant costs are higher while the clinical outcomes are similar to ACDF, preventing CASP might be a reason for ACDA to be a more cost-effective technique in the long term.

Methods and analysis

In this randomized controlled trial, patients will be randomized to receive ACDF or ACDA in a 1:1 ratio. Adult patients with single- or multi-level CDDD and symptoms of radiculopathy and/or myelopathy will be included. The primary outcome is cost-effectiveness and cost-utility of both techniques from a healthcare and societal perspective. Secondary objectives are the differences in clinical and radiological outcomes between the two techniques, as well as the qualitative process surrounding anterior decompression surgery. All outcomes will be measured at baseline and every 6 months until 4 years post-surgery.

Discussion

High-quality evidence regarding the cost-effectiveness of both ACDA and ACDF is lacking; to date, there are no prospective trials from a societal perspective. Considering the aging of the population and the rising healthcare costs, there is an urgent need for a solid clinical cost-effectiveness trial addressing this question.

Trial registration

ClinicalTrials.gov NCT04623593. Registered on 29 September 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06574-5.

Cost-effectiveness of anterior surgical decompression surgery for cervical degenerative disk disease: a systematic review of economic evaluations

PURPOSE

No clear consensus exists on which anterior surgical technique is most cost-effective for treating cervical degenerative disk disease (CDDD). One of the most common treatment options is anterior cervical discectomy with fusion (ACDF). Anterior cervical discectomy with arthroplasty (ACDA) was developed in an effort to reduce the incidence of clinical adjacent segment pathology and associated additional surgeries by preserving motion. This systematic review aims to evaluate the evidence regarding the cost-effectiveness of anterior surgical decompression techniques used to treat radiculopathy and/or myelopathy caused by CDDD.

METHODS

The search was conducted in PubMed, EMBASE, Web of Science, CINAHL, EconLit, NHS-EED and the Cochrane Library. Studies were included if healthcare costs and utility or effectivity measurements were mentioned.

RESULTS

A total of 23 studies were included out of the 1327 identified studies. In 9 of the 13 studies directly comparing ACDA and ACDF, ACDA was the most cost-effective technique, with an incremental cost effectiveness ratio ranging from $2.900/QALY to $98.475/QALY. There was great heterogeneity between the costs of due to different in- and exclusion criteria of costs and charges, cost perspective, baseline characteristics, and calculation methods. The methodological quality of the included studies was moderate.

CONCLUSION

The majority of studies report ACDA to be a more cost-effective technique in comparison with ACDF. The lack of uniform literature impedes any solid conclusions to be drawn. There is a need for high-quality cost-effectiveness research and uniformity in the conduct, design and reporting of economic evaluations concerning the treatment of CDDD.

TRIAL REGISTRATION

PROSPERO Registration: CRD42020207553 (04.10.2020).

Degenerative Cervical Myelopathy: Pathophysiology and Current Treatment Strategies

Chronic compression or ischemia of the spinal cord in the cervical spine causes a clinical syndrome known as cervical myelopathy. Recently, a new term “degenerative cervical myelopathy (DCM)” was introduced. DCM encompasses spondylosis, intervertebral disk herniation, facet arthrosis, ligamentous hypertrophy, calcification, and ossification. The pathophysiology of DCM includes structural and functional abnormalities of the spinal cord caused by static and dynamic factors. In nonoperative patients, cervical myelopathy has a poor prognosis. Surgical treatments, such as anterior or posterior decompression accompanying arthrodesis, arthroplasty, or laminoplasty, should be considered for patients with chronic progressive cervical myelopathy. Surgical decompression can prevent the progression of myelopathy and improve the neurologic status, functional outcomes, and quality of life, irrespective of differences in medical systems and sociocultural determinants of health. The anterior surgical approach to the cervical spine has the advantage of removing or floating the intervertebral disk, osteophytes, and ossification of the posterior longitudinal ligament that compress the spinal cord directly. The posterior surgical approach to the cervical spine is mainly used for multisegment spinal cord compression in patients with cervical lordosis. In this review article, we addressed the pathophysiology, clinical manifestations, differential diagnosis, and treatment options for DCM.

A Comparative in vivo Study of Semi-constrained and Unconstrained Cervical Artificial Disc Prostheses

PURPOSE

The objective of this study is to directly compare different types of cervical artificial disc implants using an in vivo model capable of simulating the axial load on a neck that is similar to the human neck.

METHODS

Cervical arthroplasty was performed at C3-4 in 14 healthy female adult Alpine goats. The goats were divided into three groups. Group A received Bryan (unconstrained one-piece design); Group B received ProDisc-C (semi-constrained two-piece design); and Group C received Mobi-C (unconstrained three-piece design) artificial discs. The goats were monitored in a veterinary unit for 6 months with radiography at regular intervals.

RESULTS

Each goat tolerated cervical arthroplasty well and had satisfactory placement of their implant per intra-operative radiography. Implants monitored in Group A demonstrated no migration. One out of five implants in Group B experienced anterior migration at 3 months. In Group C, anterior migration and disintegration occurred in all four implants, with migration occurring during the first postoperative week in three implants and after 5 weeks in the fourth.

CONCLUSIONS

Unconstrained multi-piece artificial cervical discs may be prone to anterior migration and extrusion out of the disc space. This outcome deserves attention in individuals with a hypermobile neck and/or an occupation involving the use of a head-supported mass, such as helmets.

Safety and efficacy of cervical disc arthroplasty in preventing the adjacent segment disease: a meta-analysis of mid- to long-term outcomes in prospective, randomized, controlled multicenter studies

Objectives

Cervical disc arthroplasty (CDA) has become an alternative treatment for cervical radiculopathy and myelopathy. This technique preserves appropriate motion at both the index and adjacent disc levels and consequently may prevent adjacent segment degeneration (ASD). The authors performed a meta-analysis to compare the safety and efficacy of CDA to those of the gold standard, anterior cervical discectomy and fusion (ACDF). Both surgical and clinical parameters were employed to verify the hypothesis that CDA can reduce the risk of ASD.

Methods

The meta-analysis comprised high-quality randomized controlled trials that compared CDA and ACDF treatments of cervical degenerative disc disease. Included papers reported data for at least one of the following outcomes: 1) surgical parameters, 2) questionnaire clinical indices (pre- and postoperative values), and 3) complication rates at 24 months; in addition, for ASD we analyzed 60 month or longer follow-ups. We used mean differences (MDs) or ORs to compare treatment effects between CDA and ACDF.

Results

Twenty studies with 3,656 patients (2,140 with CDA and 1,516 with ACDF) met the inclusion criteria. CDA surgery, with mean duration longer than that of ACDF, was associated with higher blood loss. Visual analog scale neck pain score was significantly smaller for CDA (mean difference =−2.30, 95% CI [−3.72; −0.87], P=0.002). The frequency of dysphagia/dysphonia (OR =0.69, 95% CI [0.49; 0.98], P=0.04) as well as the long-term ASD rate for CDA was significantly smaller (OR =0.33, 95% CI [0.21; 0.50], P<0.0001).

Conclusion

A significantly lower probability of ASD reoperations in the CDA cohort after a 60-month or longer follow-up was the most important finding of this study. Despite the moderate quality of this evidence, the pooled data corroborated for the very first time that CDA was efficacious in preventing ASD.

Cervical Disc Arthroplasty: A Comprehensive Review of Single-Level, Multilevel, and Hybrid Procedures

STUDY DESIGN

Systematic review.

OBJECTIVES

Degenerative disc disease and spondylosis resulting in radiculopathy and retrodiscal myelopathy are among the most frequently encountered cervical spinal disorders. Traditionally, anterior cervical discectomy and fusion (ACDF) has successfully achieved neural decompression and restored intradiscal height in these conditions. Unfortunately, nonunion and iatrogenic adjacent segment pathology associated with fusion procedures in the cervical spine has led to an interest in motion-preserving procedures. Cervical disc arthroplasty (CDA) was developed in hopes of preserving cervical biomechanics while mitigating the complications associated with ACDF. Through a systematic review of both published and ongoing studies on single- and multilevel CDA, and hybrid surgeries, we aim to provide evidence for their safety and efficacy in the treatment of various cervical pathologies.

METHODS

A systematic search of several large databases, including Cochrane Central, PubMed, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry was conducted to identify published studies and ongoing clinical trials on CDA and hybrid surgery.

RESULTS

Among the relevant studies reviewed, 3 were randomized controlled trials, 2 systematic reviews, as well as multiple prospective case series, biomechanical studies, and meta-analyses.

CONCLUSION

Over the past decade, multiple high-quality studies have shown that single-level CDA can offer equivalent clinical outcomes with a reduction in secondary procedures and total cost when compared to ACDF. However, more recently there has been an increasing prevalence of 2-level CDA and hybrid surgery. Although the data regarding these multilevel procedures is less robust, it appears that they may be as effective as their single-level counterparts.

Cervical Total Disk Arthroplasty

In the United States, cervical total disk arthroplasty (TDA) is US Federal Drug Administration (FDA) approved for use in both 1 and 2-level constructions for cervical disk disease resulting in myelopathy and/or radiculopathy. TDA designs vary in form, function, material composition, and even performance in?vivo. However, the therapeutic goals are the same: to remove the painful degenerative/damaged elements of the intervertebral discoligamenous joint complex, to preserve or restore the natural range of spinal motion, and to mitigate stresses on adjacent spinal segments, thereby theoretically limiting adjacent segment disease (ASDis). Cervical vertebrae exhibit complex, coupled motions that can be difficult to artificially replicate. Commonly available TDA designs include ball-and-socket rotation-only prostheses, ball-and-trough rotation and anterior-posterior translational prostheses, as well as unconstrained elastomeric disks that can rotate and translate freely in all directions. Each design has its respective advantages and disadvantages. At this time, available clinical evidence does not favor 1 design philosophy over another. The superiority of cervical TDA over the gold-standard anterior cervical discectomy and fusion is a subject of great controversy. Although most studies agree that cervical TDA is at least as effective as anterior cervical discectomy and fusion at reducing or eliminating preoperative pain and neurological symptoms, the clinical benefits of motion preservation- that is, reduced incidence of ASDis-are far less clear. Several short-to-mid-term studies suggest that disk arthroplasty reduces the radiographic incidence of adjacent segment degeneration; however, the degree to which this is clinically significant is disputed. At this time, TDA has not been clearly demonstrated to reduce symptomatic?ASDis.

Symptomatic Adjacent Segment Disease After Anterior Cervical Discectomy for Single-level Degenerative Disk Disease

STUDY DESIGN

A prospective cohort of 142 patients underwent either anterior cervical discectomy alone, anterior cervical discectomy with fusion by cage stand-alone, or anterior cervical discectomy with arthroplasty. We then followed up on their condition for a mean of 9.1±1.9 years (5.6-12.2 y) later.

OBJECTIVE

We aimed to evaluate the annual rate of clinically symptomatic adjacent segment disease (ASD) and to analyze predictive factors.

SUMMARY OF BACKGROUND DATA

Until recent, ASD has been predominantly evaluated radiologically. It is not known whether all patients had complaints. A frequent cited annual rate of ASD is 2.9%, but a growing number of studies report a lower annual rate. Furthermore, maintaining motion to prevent ASD is one reason for implanting a cervical disk prosthesis. However, the results of studies contradict one another.

METHODS

Participants took part in a randomized controlled trial that ended prematurely because of the publication of evidence that did not justify continuation of the trial. The patients were randomly allocated to 3 groups, each of which received one of the abovementioned treatments. We defined symptomatic ASD as signs and symptoms caused by degeneration of an intervertebral disk adjacent to a level of previous anterior cervical disk surgery. At the last follow-up, we were able to ascertain whether clinically symptomatic ASD was present in any of the participants.

RESULTS

The overall annual rate of symptomatic ASD was 0.7%. We found no statistically significant correlations between any of the investigated factors and symptomatic ASD except for the surgical method used. Symptomatic ASD was seen less often in anterior cervical discectomy solely or anterior cervical discectomy with arthroplasty than in anterior cervical discectomy with fusion by plate fixation.

CONCLUSIONS

The annual rate of symptomatic ASD after an anterior cervical discectomy procedure was estimated to be 0.7%. This seems to be related to the procedure, although firm conclusions cannot be drawn.

LEVEL OF EVIDENCE

Level 2-prospective cohort.

The 5-year cost-effectiveness of two-level anterior cervical discectomy and fusion or cervical disc replacement: a Markov analysis

BACKGROUND CONTEXT

Anterior cervical discectomy and fusion (ACDF) and cervical disc replacement (CDR) are both acceptable surgical options for the treatment of cervical myelopathy and radiculopathy. To date, there are limited economic analyses assessing the relative cost-effectiveness of two-level ACDF versus CDR.

PURPOSE

The purpose of this study was to determine the 5-year cost-effectiveness of two-level ACDF versus CDR.

STUDY DESIGN

The study design is a secondary analysis of prospectively collected data.

PATIENT SAMPLE

Patients in the Prestige cervical disc investigational device exemption (IDE) study who underwent either a two-level CDR or a two-level ACDF were included in the study.

OUTCOME MEASURES

The outcome measures were cost and quality-adjusted life years (QALYs).

MATERIALS AND METHODS

A Markov state-transition model was used to evaluate data from the two-level Prestige cervical disc IDE study. Data from the 36-item Short Form Health Survey were converted into utilities using the short form (SF)-6D algorithm. Costs were calculated from the payer perspective. QALYs were used to represent effectiveness. A probabilistic sensitivity analysis (PSA) was performed using a Monte Carlo simulation.

RESULTS

The base-case analysis, assuming a 40-year-old person who failed appropriate conservative care, generated a 5-year cost of $130,417 for CDR and $116,717 for ACDF. Cervical disc replacement and ACDF generated 3.45 and 3.23 QALYs, respectively. The incremental cost-effectiveness ratio (ICER) was calculated to be $62,337/QALY for CDR. The Monte Carlo simulation validated the base-case scenario. Cervical disc replacement had an average cost of $130,445 (confidence interval [CI]: $108,395-$152,761) with an average effectiveness of 3.46 (CI: 3.05-3.83). Anterior cervical discectomy and fusion had an average cost of $116,595 (CI: $95,439-$137,937) and an average effectiveness of 3.23 (CI: 2.84-3.59). The ICER was calculated at $62,133/QALY with respect to CDR. Using a $100,000/QALY willingness to pay (WTP), CDR is the more cost-effective strategy and would be selected 61.5% of the time by the simulation.

CONCLUSIONS

Two-level CDR and ACDF are both cost-effective strategies at 5 years. Neither strategy was found to be more cost-effective with an ICER greater than the $50,000/QALY WTP threshold. The assumptions used in the analysis were strongly validated with the results of the PSA.

National outcomes following single-level cervical disc arthroplasty versus anterior cervical discectomy and fusion

Background

To compare the differences in the thirty-day postoperative outcomes between cervical disc arthroplasty (CDA) and anterior cervical discectomy and fusion (ACDF).

Methods

Patients undergoing primary single-level ACDF and CDA from 2010-2014 were identified by unique Current Procedural Terminology (CPT) codes within the American College of Surgeon's National Surgical Quality Improvement Program (NSQIP) database. Primary outcomes included surgical and medical complications, length of hospital stay (LOS), unplanned readmission, return to operating room, and mortality all occurring within 30 days of the initial procedure. Patients were propensity score-matched to reduce selection bias and differences in preoperative characteristics. Multivariate logistic regression models were utilized to determine associations between covariates and primary outcomes of interest.

Results

Propensity score-matching produced a cohort of 1,305 patients with 652 (50.0%) ACDF and 653 (50.0%) CDA patients. There were no statistically significant differences in the development of major surgical or medical complications between the groups. ACDF patients experienced a significantly longer LOS (2.3±14.8 vs. 1.1±1.0 days, P=0.034) and unplanned hospital readmission (1.8% vs. 0.2%, P=0.002). For ACDF patients, increased LOS [odds ratios (OR), 4.21; 95% confidence interval (CI), 1.29-13.73; P=0.017] and increased readmission (OR, 12.17; 95% CI, 1.16-127.23; P=0.037) persisted in the multivariate model. Elevated ASA classification, preoperative anemia and elevated white blood cell count (WBC) were also associated with a significantly increased LOS.

Conclusions

Although ACDF and CDA can be indicated for similar cervical pathologies, the latter can be performed safely and effectively with comparable perioperative risk of major complications. The increased readmission rate and LOS for patients undergoing ACDF may have significant impact on patient cost and outcomes.

Indirect meta-analysis comparing clinical outcomes of total cervical disc replacements with fusions for cervical degenerative disc disease

Anterior cervical discectomy and fusion (ACDF) and total cervical disc replacement (TDR) are considered effective treatments for patients with cervical degenerative disc disease (CDDD). An indirect meta-analysis including 19 randomized controlled trials (5343 patients) was conducted to compare the clinical outcomes of ACDF with TDR. Primary outcomes including functional indicators (NDI [neck disability index] score, neurological success and patient satisfaction), secondary outcomes including surgical outcomes (operation time, blood loss and length of stay) and secondary surgical procedures (secondary surgery at an adjacent level, secondary surgery at the index level, secondary surgery at both levels, removal, reoperation, revision and supplemental fixation) were included in the study. TDR using the Bryan disc was associated with a greater improvement in NDI score than ACDF (MD = -5.574, 95% CrIs [credible intervals] -11.73--0.219). For neurological success, the Bryan (odds ratio [OR] = 0.559, 95% CrIs 0.323-0.955) and Prestige (OR = 0.474, 95% CrIs 0.319-0.700) discs were superior to ACDF. However, no differences in the patient satisfaction rate were shown between TDR and ACDF. For patients with CDDD, ACDF using allograft and a plate is most effective for determining the surgical parameters. Moreover, TDR using the ProDisc-C, Mobi-C, Prestige and Bryan discs are good choices for improving functional outcomes and reducing secondary surgeries.

Cervical disc replacement surgery: biomechanical properties, postoperative motion, and postoperative activity levels

PURPOSE OF REVIEW

Cervical disc arthroplasty (CDA) is an evolving technique used in the treatment of cervical disc disease. To remain up to date on studies regarding its efficacy, we sought to answer three questions: What do biomechanical studies demonstrate in regard to the kinematics of CDA? How does CDA affect cervical motion? What are the postoperative activity levels of patients after cervical disc arthroplasty?

RECENT FINDINGS

1) In regard to biomechanics, recent data suggests that CDA maintains motion while possibly altering facet biomechanics. 2) Radiographic data indicates a reliable maintenance of motion in the short and medium term. 3) Postoperative activity levels are assessed with clinical outcome data which demonstrate reliable improvement in pain and function. The data reviewed here establishes CDA as an efficacious treatment in the relief of symptoms from CDD. It is important to note however that an evaluation of CDA would benefit from more robust data, specifically in regards to long-term clinical outcomes.

Management of Symptomatic Cervical Disk Herniation: A Survey Among Dutch Neurosurgeons

STUDY DESIGN

A questionnaire survey.

OBJECTIVE

To assess the preferred surgical technique, the optimal timing of surgery, and the expectations of different surgical techniques of neurosurgeons in the Netherlands, regarding patients with cervical disc herniation (CDH).

SUMMARY OF BACKGROUND DATA

To treat CDH, multiple surgical techniques are performed. Due to the lack of consensus, the daily routine management may vary.

METHODS

All 134 neurosurgeons of the Dutch Association of Neurosurgery were sent a survey, evaluating the operative management as well as the attitude towards different surgical treatments for CDH.

RESULTS

Ninety-six (74.4%) of the neurosurgeons treating CDH completed the survey. Anterior cervical discectomy with fusion (ACDF) was the standard procedure for the majority of neurosurgeons (76.3%). ACDF was expected to have the highest effectiveness on arm pain, yet also a higher risk for complications as compared with anterior cervical discectomy (ACD). Approximately, 47.9% of the surgeons regarded a minimal duration of 8 to 12 weeks of radicular arm pain before deciding to perform surgery. Regarding the risk of recurrent CDH, DCF was expected to give the highest risk, whereas ACDF the lowest.

CONCLUSION

Despite the lack of solid evidence in favor for ACDF this survey showed that ACDF is the preferred technique to treat cervical radiculopathy. A minimum duration of 8 to 12 weeks of radicular arm pain was considered the optimal timing to perform surgery for CDH by the majority of the neurosurgeons. Whether to fuse or not remains a controversial subject in degenerative spinal surgery. This study emphasizes the need of high-quality evidence on the optimal surgical management of CDH.

LEVEL OF EVIDENCE

N/A.

Cost Utility Analysis of Cervical Therapeutic Medial Branch Blocks in Managing Chronic Neck Pain

Background: Controlled diagnostic studies have established the prevalence of cervical facet joint pain to range from 36% to 67% based on the criterion standard of ≥ 80% pain relief. Treatment of cervical facet joint pain has been described with Level II evidence of effectiveness for therapeutic facet joint nerve blocks and radiofrequency neurotomy and with no significant evidence for intraarticular injections. However, there have not been any cost effectiveness or cost utility analysis studies performed in managing chronic neck pain with or without headaches with cervical facet joint interventions. Study Design: Cost utility analysis based on the results of a double-blind, randomized, controlled trial of cervical therapeutic medial branch blocks in managing chronic neck pain. Objectives: To assess cost utility of therapeutic cervical medial branch blocks in managing chronic neck pain. Methods: A randomized trial was conducted in a specialty referral private practice interventional pain management center in the United States. This trial assessed the clinical effectiveness of therapeutic cervical medial branch blocks with or without steroids for an established diagnosis of cervical facet joint pain by means of controlled diagnostic blocks. Cost utility analysis was performed with direct payment data for the procedures for a total of 120 patients over a period of 2 years from this trial based on reimbursement rates of 2016. The payment data provided direct procedural costs without inclusion of drug treatments. An additional 40% was added to procedural costs with multiplication of a factor of 1.67 to provide estimated total costs including direct and indirect costs, based on highly regarded surgical literature. Outcome measures included significant improvement defined as at least a 50% improvement with reduction in pain and disability status with a combined 50% or more reduction in pain in Neck Disability Index (NDI) scores. Results: The results showed direct procedural costs per one-year improvement in quality adjusted life year (QALY) of United States Dollar (USD) of $2,552, and overall costs of USD $4,261. Overall, each patient on average received 5.7 ± 2.2 procedures over a period of 2 years. Average significant improvement per procedure was 15.6 ± 12.3 weeks and average significant improvement in 2 years per patient was 86.0 ± 24.6 weeks. Limitations: The limitations of this cost utility analysis are that data are based on a single center evaluation. Only costs of therapeutic interventional procedures and physician visits were included, with extrapolation of indirect costs. Conclusion: The cost utility analysis of therapeutic cervical medial branch blocks in the treatment of chronic neck pain non-responsive to conservative management demonstrated clinical effectiveness and cost utility at USD $4,261 per one year of QALY.

Cervical Disk Arthroplasty Versus Anterior Cervical Decompression and Fusion for the Treatment of 2-Level Cervical Spondylopathy: A Systematic Review and Meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To assess the safety and efficacy of cervical disk arthroplasty (CDA) compared with anterior cervical decompression and fusion (ACDF) for the treatment of 2-level cervical spondylopathy.

SUMMARY OF BACKGROUND DATA

CDA has emerged as a potential alternative to ACDF in patients with cervical disk degeneration. But there are no published systematic reviews and meta-analyses comparing CDA with ACDF for the treatment of 2-level cervical spondylopathy.

METHODS

The Pubmed, Embase, Web of science, Scopus, and Cochrane library databases were searched comparing CDA to ACDF in patients with 2-level cervical spondylopathy. Outcome measures were neck disability index, visual analog scale (VAS) of arm and neck pain, range of movement (ROM) at C2-C7, functional segment unit ROM, ROM at the operated level, and incidence of radiologic changes at adjacent levels approximately 2 years after surgery, as well as operating time and incidence of surgery-related complications. Mean difference (MD), odds ratios (OR), and their corresponding 95% confidence intervals (95% CIs) were calculated.

RESULTS

Six studies involving 646 patients were included. There were no significant differences in neck disability index (MD, -1.53; 95% CI -3.80 to 0.73), VAS neck pain (MD, -0.19; 95% CI -0.71 to 0.33), and VAS arm pain (MD, -0.23; 95% CI -0.61 to 0.16) between 2-level CDA and 2-level ACDF cases. ROM at C2-C7 (MD, 15.82; 95% CI, 10.66-20.99), functional segment unit ROM (MD, 8.58; 95% CI, 7.93-9.23), and ROM at the operated level (MD, 9.54; 95% CI, 7.73-11.35) were greater, but the incidence of radiologic changes at adjacent levels (OR, 0.29; 95% CI, 0.13-0.67) were lower, in 2-level CDA cases. In 2-level CDA cases, the operating time was longer (MD, 57.41; 95% CI, 24.67-90.14), but surgery-related complications rates (OR, 0.47; 95% CI, 0.30-0.74) was lower.

CONCLUSIONS

CDA may be a safe and effective alternative to ACDF for the treatment of 2-level cervical degenerative disease.

LEVEL OF EVIDENCE

Level II.

Anterior cervical disc arthroplasty (ACDA) versus anterior cervical discectomy and fusion (ACDF): a systematic review and meta-analysis

BACKGROUND

Surgical approaches are usually required in cases of severe cervical disc disease. The traditional method of anterior cervical disc fusion (ACDF) has been associated with reduced local mobility and increased occurrence of adjacent segment disease. The newer method of anterior cervical disc arthroplasty (ACDA) relies upon artificial discs of various products. Current literature is inconsistent in the comparative performance of these methods with regards to clinical, radiological and patient outcomes.

METHODS

Electronic databases, including OVID Medline, PubMed, Scopus, Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews, were comprehensively searched to retrieve studies comparing the treatment outcomes of ACDF and ACDA. Baseline characteristics and outcome data were extracted from eligible articles.

RESULTS

Two hundred and fifty five articles were identified through the database searches, and after screening 28 studies were included in the systematic review and meta-analysis. A total of 4,070 patients were included (2156 ACDA, 1914 ACDF). There was no significant difference between the two groups in operation time, blood loss during operation, long-term all-complication rate and reoperation rate at the level of injury. The ACDA group had significantly better neurological outcomes, as well as a significantly lower rate of adjacent segment diseases.

CONCLUSIONS

Compared with ACDF, the ACDA procedure is associated with improved reoperation rate and reduction in neurological deficits amongst previously demonstrated benefits. There is heterogeneity in ACDA devices; future studies are required to investigate the impact of this technique on treatment outcomes.

Degenerative cervical myelopathy

Cervical myelopathy is the most common cause of acquired spinal cord compromise. The concept of degenerative cervical myelopathy (DCM), defined as symptomatic myelopathy associated with degenerative arthropathic changes in the spine axis, is being introduced. Given its progressive nature, treatment options have to be chosen in a timely manner. Surgical options include anterior discectomy and fusion (ACDF), anterior corpectomy and fusion (ACCF), arthroplasty (in highly select cases), posterior laminectomy with/without fusion, and laminoplasty. Indications for each should be carefully considered in individual patients. Riluzole, a sodium-glutamate antagonist, is a promising option to optimize neurologic outcomes post-surgery and is being examined in the CSM-Protect Randomized Controlled Trial. Preoperative risk assessment is mandatory for prognostication. Sagittal alignment is known to play an important role to optimize surgical outcome. Guidelines for optimal management of DCM are in process. In principle, all but the mildest cases of DCM should be offered surgery for optimal outcome.

Four-year results of a prospective single-arm study on 200 semi-constrained total cervical disc prostheses: clinical and radiographic outcome

OBJECTIVE Recent studies have described encouraging outcomes after cervical total disc replacement (cTDR), but there are also critical debates regarding the long-term effects of heterotopic ossification (HO) and the prevalence of adjacent-level degeneration. The aim in this paper was to provide 4-year clinical and radiographic outcome results on the activ C disc prosthesis. METHODS A total of 200 subjects underwent single-level activ C (Aesculap AG) implantation between C-3 and C-7 for the treatment of symptomatic degenerative disc disease. Clinical and radiographic assessments were performed preoperatively, intraoperatively, at discharge, and again at 6 weeks, 6 months, 1 year, 2 years, and 4 years. Radiographic evaluations were done by an independent core laboratory using a specific software for quantitative motion analysis. RESULTS Neck Disability Index (NDI) and visual analog scale (VAS) score for neck and arm pain decreased significantly from baseline to the 4-year follow-up. The mean improvement for NDI was 20, for VAS severity and frequency of neck pain 26.4 and 28, and for VAS severity and frequency of arm pain 30.7 and 35.1, respectively. The neurological situation improved for the majority of patients (86.4%); 76.1% of cases were asymptomatic. Subsequent surgical interventions were reported in 7% of the cases, including device removals in 3%. In 2.5% a subsidence greater than 3 mm was recorded; 1 of these cases also had a migration greater than 3 mm. No device displacement, expulsion, disassembly, loose or fractured device, osteolysis, or facet joint degeneration at the index level was observed. Segmental lordotic alignment changed from -2.4° preoperatively to -6.2° at 4 years, and postoperative height was maintained during the follow-up. Advanced HO (Grade III and IV) was present in 27.1% of the cases; 82.4% showed segmental mobility. A progression of radiographic adjacent-segment degeneration occurred in 28.2%, but only 4.5% required surgical treatment. CONCLUSIONS The activ C is a safe and effective device for cervical disc replacement confirming the encouraging results after cTDR. Clinical trial registration no.: NCT02492724 ( clinicaltrials.gov ).

Long term follow-up of cervical intervertebral disc herniation inpatients treated with integrated complementary and alternative medicine: a prospective case series observational study

Background

Symptomatic cervical intervertebral disc herniation (IDH) presenting as neck pain accompanied by arm pain is a common affliction whose prevalence continues to rise, and is a frequent reason for integrative inpatient care using complementary and alternative medicine (CAM) in Korea. However, studies on its long term effects are scarce.

Methods

A total 165 patients with cervical IDH admitted between January 2011 and September 2014 to a hospital that provides conventional and Korean medicine integrative treatment with CAM as the main modality were observed in a prospective observational study. Patients underwent CAM treatment administered by Korean medicine doctors (KMDs) in accordance with a predetermined protocol for the length of hospital stay, and additional conventional treatment by medical doctors (MDs) as referred by KMDs. Short term outcomes were assessed at discharge and long term follow-ups were conducted through phone interviews after discharge. Numeric rating scale (NRS) of neck and radiating arm pain, neck disability index (NDI), 5-point patient global impression of change (PGIC), and factors influencing long term satisfaction rates in PGIC were assessed.

Results

Of 165 patients who received inpatient treatment 20.8 ± 11.2 days, 117 completed the long term follow-up up at 625.36 ± 196.7 days post-admission. Difference in NRS between admission and discharge in the long term follow-up group (n = 117) was 2.71 (95 % CI, 2.33, 3.09) for neck pain, 2.33 (95 % CI, 1.9, 2.77) for arm pain, and that of NDI 14.6 (95 % CI, 11.89, 17.32), and corresponding scores in the non-long term follow-up group (n = 48) were 2.83 (95 % CI, 2.22, 3.45) for neck pain, 2.48 (95 % CI, 1.84, 3.12) for arm pain, and that of NDI was 14.86 (95 % CI, 10.41, 19.3). Difference in long term NRS of neck pain and arm pain from baseline was 3.15 (95 % CI, 2.67, 3.64), and 2.64 (95 % CI, 1.99, 3.29), respectively. PGIC was reported to be “satisfactory” or higher in 79.5 % of patients at long term follow-up.

Conclusions

Though the observational nature of this study limits us from drawing a more decisive conclusion, these results suggest that integrative treatment focused on CAM in cervical IDH inpatients may achieve favorable results in pain and functional improvement.

Trial registration

ClinicalTrials.gov Identifier: NCT02257723. Registered October 2, 2014.

Cervical arthroplasty with ROTAIO® cervical disc prosthesis: first clinical and radiographic outcome analysis in a multicenter prospective trial

Background

Cervical Disc Arthroplasty (CDA) seems to be an alternative to Anterior Cervical Decompression and Fusion (ACDF) and was developed to minimize the risk of Adjacent Segment Disease (ASD). The ROTAIO Cervical Disc Prosthesis represents a new unconstrained implant with a variable centre of rotation which should enable physiological facet-guided movement. The aim of this current study was to evaluate the clinical outcomes after arthroplasty using ROTAIO Cervical Disc Prosthesis.

Method

Twenty-seven female and 18 male patients (n = 45) with a mean age of 43.7 ± 7.8 years were prospectively followed up for a maximum of 24 month. Clinical outcomes were assessed by Neck Disability Index (NDI), visual analogue scale (VAS) scores for neck and arm pain, patients´ overall satisfaction and the usage of analgesics. Additionally, radiographic information including ROM of the functional spinal unit (FSU) and signs of adjacent segment disease were recorded.

Results

NDI and VAS scores showed significant improvement 6 months after surgery and at last follow-up (p < 0.001). Concerning overall satisfaction 95.7 % of the patients showed good to excellent results at the last visit and a significant reduction of analgesic usage was observed (p < 0.001). Radiographic measurements showed a mean increase of ROM up to 8.40° in the treated FSU at last follow-up (p < 0.001). No signs of anterior migration or dislocation of the prosthesis and no subsidence was recorded radiographically. There were no major complications and a low rate of secondary procedures (2.2 %).

Conclusion

In the 24-months follow-up the ROTAIO Cervical Disc Prosthesis provided excellent clinical and radiographical results and seems to be safe and effective for the treatment of symptomatic single-level degenerative disc disease.

Cervical disc arthroplasty with PRESTIGE LP disc versus anterior cervical discectomy and fusion: a prospective, multicenter investigational device exemption study

OBJECT This study compared the safety and efficacy of treatment with the PRESTIGE LP cervical disc versus a historical control anterior cervical discectomy and fusion (ACDF). METHODS Prospectively collected PRESTIGE LP data from 20 investigational sites were compared with data from 265 historical control ACDF patients in the initial PRESTIGE Cervical Disc IDE study. The 280 investigational patients with single-level cervical disc disease with radiculopathy and/or myelopathy underwent arthroplasty with a low-profile artificial disc. Key safety/efficacy outcomes included Neck Disability Index (NDI), Neck and Arm Pain Numerical Rating Scale scores, 36-Item Short Form Health Survey (SF-36) score, work status, disc height, range of motion, adverse events (AEs), additional surgeries, and neurological status. Clinical and radiographic evaluations were completed preoperatively, intraoperatively, and at 1.5, 3, 6, 12, and 24 months postoperatively. Predefined Bayesian statistical methods with noninformative priors were used, along with the propensity score technique for controlling confounding factors. Analysis by independent statisticians confirmed initial statistical findings. RESULTS The investigational and control groups were mostly similar demographically. There was no significant difference in blood loss (51.0 ml [investigational] vs 57.1 ml [control]) or hospital stay (0.98 days [investigational] vs 0.95 days [control]). The investigational group had a significantly longer operative time (1.49 hours vs 1.38 hours); 95% Bayesian credible interval of the difference was 0.01-0.21 hours. Significant improvements versus preoperative in NDI, neck/arm pain, SF-36, and neurological status were achieved by 1.5 months in both groups and were sustained at 24 months. Patient follow-up at 24 months was 97.1% for the investigational group and 84.0% for the control group. The mean NDI score improvements versus preoperative exceeded 30 points in both groups at 12 and 24 months. SF-36 Mental Component Summary superiority was established (Bayesian probability 0.993). The mean SF-36 PCS scores improved by 14.3 points in the investigational group and by 11.9 points in the control group from baseline to 24 months postoperatively. Neurological success at 24 months was 93.5% in the investigational group and 83.5% in the control group (probability of superiority ~ 1.00). At 24 months, 12.1% of investigational and 15.5% of control patients had an AE classified as device or device/surgical procedure related; 14 (5.0%) investigational and 21 (7.9%) control patients had a second surgery at the index level. The median return-to-work time for the investigational group was 40 days compared with 60 days for the control group (p = 0.020 after adjusting for preoperative work status and propensity score). Following implantation of the PRESTIGE LP device, the mean angular motion was maintained at 12 months (7.9°) and 24 months (7.5°). At 24 months, 90.0% of investigational and 87.7% of control patients were satisfied with the results of surgery. PRESTIGE LP superiority on overall success (without disc height success), a composite safety/efficacy end point, was strongly supported with 0.994 Bayesian probability. CONCLUSIONS This device maintains mean postoperative segmental motion while providing the potential for biomechanical stability. Investigational patients reported significantly improved clinical outcomes compared with baseline, at least noninferior to ACDF, up to 24 months after surgery.

Correlation between cervical lordosis and adjacent segment pathology after anterior cervical spinal surgery

PURPOSE

To evaluate the incidence and risk factors for adjacent segment pathology (ASP) after anterior cervical spinal surgery.

METHODS

Fourteen patients (12 male, mean age 47.1 years) who underwent single-level cervical disk arthroplasty (CDA group) and 28 case-matched patients (24 male, mean age 53.6 years) who underwent single-level anterior cervical discectomy and fusion (ACDF group) were included. Presence of radiologic ASP (RASP) was based on observed changes in anterior osteophytes, disks, and calcification of the anterior longitudinal ligament on lateral radiographs.

RESULTS

The mean follow-up period was 43.4 months in the CDA group and 44.6 months in the ACDF group. At final follow-up, ASP was observed in 5 (35.7%) CDA patients and 16 (57.1%) ACDF patients (p = 0.272). The interval between surgery and ASP development was 33.8 months in the CDA group and 16.3 months in the ACDF group (p = 0.046). The ASP risk factor analysis indicated postoperative cervical angle at C3-7 being more lordotic in non-ASP patients in both groups. Restoration of lordosis occurred in the CDA group regardless of the presence of ASP, but heterotopic ossification development was associated with the presence of ASP in the CDA group. And the CDA group had significantly greater clinical improvements than those in the ACDF group when ASP was present.

CONCLUSION

In both CDA and ACDF patients, RASP developed, but CDA was associated with a delay in ASP development. A good clinical outcome was expected in CDA group, even when ASP developed. Restoration of cervical lordosis was an important factor in anterior cervical spine surgery.

Postoperative segmental hypermobility after cervical arthroplasty: A possible pathomechanism for outcome failure

We present a 41-year-old man who underwent a cervical discarthroplasty (CDA) C5-6 procedure with an increase of the segmental range of motion from 2.8° to 6.9° and an increase in disc height from 5.8mm preoperatively to 10.4mm postoperatively with an unfavorable long-term clinical outcome. Both anterior cervical discectomy with fusion (ACDF), as well as CDA have been proven to be successful procedures in the management of cervical radiculopathy with good to excellent outcomes and low complication rates. The rationale for CDA over ACDF highlights the preservation of segmental motion and reduction of the incidence of adjacent segment disease. This case report suggests that a hypermobility syndrome and also an overcorrection of the cervical range of motion may be responsible for an unfavorable outcome after CDA.

Lumbar total disc replacement by less invasive lateral approach: a report of results from two centers in the US IDE clinical trial of the XL TDR® device

PURPOSE

To evaluate the clinical and radiographic outcomes following total disc arthroplasty using the XL TDR(®) Lumbar Disc in the treatment of patients with symptomatic degenerative disc disease at one level between L1-2 and L4-5.

METHODS

Data were compiled from two centers participating in a prospective, multi-center Food and Drug Administration-approved investigational device exemption clinical trial enrolling patients with single-level lumbar degenerative disc disease unresponsive to non-operative treatment. Longitudinal outcomes were evaluated through 3-year follow-up and included patient-reported pain, function, and general health, as well as radiographic measures such as maintenance of disc height and range of motion.

RESULTS

The two-center cohort included 64 treated patients, 42 % female, averaging 45.3 years of age (range 26-67). The majority of procedures were performed at the L4-5 level (75 %), uncomplicated, with minimal blood loss (88 % 0-50 cc), and in an outpatient setting (93.8 %). Postoperative events included 10 patients (15.6 %) with new hip flexion weakness, 7 (10.9 %) with new lower extremity weakness, and 10 (15.6 %) with new lower extremity sensory deficits, all resolved by 3 months in all but two patients whose deficits were prolonged but eventually resolved. Average disc height increased postoperatively from 7.2 to 12.1 mm (69 %), and was 10.7 mm (49 % increase from preoperative) at 3 years. Flexion/extension range of motion averaged 5.9° (SD 4.8°) at 3 years, and was not statistically different from preoperative (p = 0.471). Heterotopic ossification interfering with segmental motion was noted in 3 patients (10.3 %) at 3 years, none ankylosed (Grade IV). Postoperative improvement in patient-reported outcomes was significant (p < 0.01 for all measures) and maintained through 3-year follow-up. Satisfaction with results was reported by 85 % (51/60) of patients at 2 years and 93 % (28/30) at 3 years. There were no revisions through 3 years postoperative.

CONCLUSIONS

The results following XL TDR show good clinical and radiographic outcomes out to 3 years postoperative, with clinically significant improvements in pain, function, and general health, few complications, and high patient satisfaction.

Comparison of revision surgeries for one- to two-level cervical TDR and ACDF from 2002 to 2011

BACKGROUND CONTEXT

Cervical total disc replacement (TDR) and anterior cervical discectomy and fusion (ACDF) provide comparable outcomes for degenerative cervical pathology. However, revisions of these procedures are not well characterized.

PURPOSE

The purpose of this study is to examine the rates, epidemiology, perioperative complications, and costs between the revision procedures and to compare these outcomes with those of primary cases.

STUDY DESIGN

This study is a retrospective database analysis.

PATIENT SAMPLE

A total of 3,792 revision and 183,430 primary cases from the Nationwide Inpatient Sample (NIS) database from 2002 to 2011 were included.

OUTCOME MEASURES

Incidence of revision cases, patient demographics, length of stay (LOS), in-hospital costs, mortality, and perioperative complications.

METHODS

Patients who underwent revision for either one- to two-level cervical TDR or ACDF were identified. SPSS v.20 was used for statistical analysis with χ(2) test for categorical data and independent sample t test for continuous data. The relative risk for perioperative complications with revisions was calculated in comparison with primary cases using a 95% confidence interval. An alpha level of less than 0.05 denoted statistical significance.

RESULTS

There were 3,536 revision one- to two-level ACDFs and 256 revision cervical TDRs recorded in the NIS database from 2002 to 2011. The revision cervical TDR cohort demonstrated a significantly greater LOS (3.18 vs. 2.25, p<.001), cost ($16,998 vs. $15,222, p=.03), and incidence of perioperative wound infections (13.6 vs. 5.3 per 1,000, p<.001) compared with the ACDF revision cohort (p<.001). There were no differences in mortality between the revision surgical cohorts. Compared with primary cases, both revision cohorts demonstrated a significantly greater LOS and cost. Furthermore, patients who underwent revision demonstrated a greater incidence and risk for perioperative wound infections, hematomas, dysphagia, and neurologic complications relative to the primary procedures.

CONCLUSIONS

This study demonstrated a significantly greater incidence of perioperative wound infection, LOS, and costs associated with a TDR revision compared with a revision ACDF. We propose that these differences are by virtue of the inherently more invasive nature of revising TDRs. In addition, compared with primary cases, revision procedures are associated with greater costs, LOS, and complications including wound infections, dysphagia, hematomas, and neurologic events. These additional risks must be considered before opting for a revision procedure.

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

BACKGROUND

Cervical 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.

PURPOSE

To critically assess the available literature on CDA with the Mobi-C prosthesis, with a focus on two-level CDA.

METHODS

All 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.

RESULTS

Fifteen 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.

CONCLUSION

One-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 5-year cost-effectiveness of anterior cervical discectomy and fusion and cervical disc replacement: a Markov analysis

STUDY DESIGN

A Markov state-transition model was developed to evaluate the cost-effectiveness of anterior cervical discectomy and fusion (ACDF) and cervical disc replacement (CDR) at 5 years.

OBJECTIVE

To determine the cost-effectiveness of ACDF and CDR at 5 years.

SUMMARY OF BACKGROUND DATA

ACDF and CDR are surgical options for the treatment of an acute cervical disc herniation with associated myelopathy/radiculopathy. Cost-effectiveness analysis provides valuable information regarding which intervention will lead to a more efficient utilization of health care resources.

METHODS

Outcome and complication probabilities were obtained from existing literature. Physician costs were based on a fixed percentage of 140% of 2010 Medicare reimbursement. Hospital costs were determined from the Nationwide Inpatient Sample. Utilities were derived from responses to health state surveys (Short Form 36) at baseline and at 5 years from the treatment arms of the ProDisc-C trial. Incremental cost-effectiveness ratios were used to compare treatments. One-way sensitivity analyses were performed on all parameters within the model.

RESULTS

CDR generated a total 5-year cost of $102,274, whereas ACDF resulted in a 5-year cost of $119,814. CDR resulted in a generation of 2.84 quality-adjusted life years, whereas ACDF resulted in 2.81. The incremental cost-effectiveness ratio was -$557,849 per quality-adjusted life year gained. CDR remained the dominant strategy below a cost of $20,486. ACDF was found to be a cost-effective strategy below a cost of $18,607. CDR was the dominant strategy when the utility value was above 0.713. CDR remained the dominant strategy assuming an annual complication rate less than 4.37%.

CONCLUSION

ACDF and CDR were both shown to be cost-effective strategies at 5 years. CDR was found to be the dominant treatment strategy in our model. Further long-term studies evaluating the clinical and quality-of-life outcomes of these 2 treatments are needed to further validate the model.

LEVEL OF EVIDENCE

5.

Cervical arthroplasty: a critical review of the literature

BACKGROUND CONTEXT

Cervical disc arthroplasty (CDA) is a motion-preserving procedure that is an alternative to fusion. Proponents of arthroplasty assert that it will maintain cervical motion and prevent or reduce adjacent segment degeneration. Accordingly, CDA, compared with fusion, would have the potential to improve clinical outcomes. Published studies have varying conclusions on whether CDA reduces complications and/or improves outcomes. As many of these previous studies have been funded by CDA manufacturers, we wanted to ascertain whether there was a greater likelihood for these studies to report positive results.

PURPOSE

To critically assess the available literature on cervical arthroplasty with a focus on the time of publication and conflict of interest (COI).

STUDY DESIGN/SETTING

Review of the literature.

METHODS

All clinical articles about CDA published in English through August 1, 2013 were identified on Medline. Any article that presented CDA clinical results was included. Study design, sample size, type of disc, length of follow-up, use of statistical analysis, quality-of-life (QOL) outcome scores, COI, and complications were recorded. A meta-analysis was conducted stratifying studies by COI and publication date to identify differences in complication rates reported.

RESULTS

Seventy-four studies were included that investigated 8 types of disc prosthesis and 22 met the criteria for a randomized controlled trial (RCT). All Level Ib RCTs reported superior quality-of-life outcomes for CDA versus anterior cervical discectomy and fusion (ACDF) at 24 months. Fifty of the 74 articles (68%) had a disclosure section, including all Level Ib RCTs, which had significant COIs related to the respective studies. Those studies without a COI reported mean weighted average adjacent segment disease rates of 6.3% with CDA and 6.2% with ACDF. In contrast, the reverse was reported by studies with a COI, for which the averages were 2.5% with CDA and 6.3% with ACDF. Those studies with a COI (n=31) had an overall weighted average heterotopic ossification rate of 22%, whereas those studies with no COI (n=43) had a rate of 46%.

CONCLUSIONS

Associated COIs did not influence QOL outcomes. Conflicts of interest were more likely to be present in studies published after 2008, and those with a COI reported greater adjacent segment disease rates for ACDF than CDA. In addition, heterotopic ossification rates were much lower in studies with COI versus those without COI. Thus, COIs did not affect QOL outcomes but were associated with lower complication rates.

Cervical radicular pain: the role of interlaminar and transforaminal epidural injections

Chronic neck pain and cervical radicular pain are relatively common in the adult population. Treatment for chronic radicular pain recalcitrant to conservative management includes surgical management as well as interventional techniques with epidural injections utilizing either an interlaminar approach or transforaminal approach. Although there have been multiple systematic reviews and randomized clinical trials of cervical interlaminar epidural injections, the literature is sparse in reference to cervical transforaminal epidural injections. Overall, there is good evidence for the effectiveness of cervical interlaminar epidural injections in managing cervical disc herniation and fair evidence in managing central spinal stenosis and postsurgery syndrome. The evidence is poor, however, for cervical transforaminal epidural injections. Complications with cervical interlaminar epidural injections are rare, but more commonly occur with transforaminal epidural injections and can be fatal. Emerging concepts in pain include further randomized trials; proper placebo design; focus on control design (either active control or placebo control); and appropriate methodologic quality assessment and evidence synthesis.

Two-year follow-up results of fluoroscopic cervical epidural injections in chronic axial or discogenic neck pain: a randomized, double-blind, controlled trial

STUDY DESIGN

A randomized, double-blind, active-controlled trial.

OBJECTIVE

To assess the effectiveness of cervical interlaminar epidural injections of local anesthetic with or without steroids for the management of axial or discogenic pain in patients without disc herniation, radiculitis, or facet joint pain.

SUMMARY OF BACKGROUND DATA

Cervical discogenic pain without disc herniation is a common cause of suffering and disability in the adult population. Once conservative management has failed and facet joint pain has been excluded, cervical epidural injections may be considered as a management tool. Despite a paucity of evidence, cervical epidural injections are one of the most commonly performed nonsurgical interventions in the management of chronic axial or disc-related neck pain.

METHODS

One hundred and twenty patients without disc herniation or radiculitis and negative for facet joint pain as determined by means of controlled diagnostic medial branch blocks were randomly assigned to one of the 2 treatment groups. Group I patients received cervical interlaminar epidural injections of local anesthetic (lidocaine 0.5%, 5 mL), whereas Group II patients received 0.5% lidocaine, 4 mL, mixed with 1 mL or 6 mg of nonparticulate betamethasone. The primary outcome measure was ≥ 50% improvement in pain and function. Outcome assessments included numeric rating scale (NRS), Neck Disability Index (NDI), opioid intake, employment, and changes in weight.

RESULTS

Significant pain relief and functional improvement (≥ 50%) was present at the end of 2 years in 73% of patients receiving local anesthetic only and 70% receiving local anesthetic with steroids. In the successful group of patients, however, defined as consistent relief with 2 initial injections of at least 3 weeks, significant improvement was illustrated in 78% in the local anesthetic group and 75% in the local anesthetic with steroid group at the end of 2 years. The results reported at the one-year follow-up were sustained at the 2-year follow-up.

CONCLUSIONS

Cervical interlaminar epidural injections with or without steroids may provide significant improvement in pain and functioning in patients with chronic discogenic or axial pain that is function-limiting and not related to facet joint pain.