Arthroplasty versus fusion in single-level cervical degenerative disc disease

One-Year Follow-Up Study on Assessing the Range of Segmental Motion and Clinical Outcomes Following Cervical Disc Arthroplasty for Treatment of Severe Cervical Disc Degeneration

BACKGROUND

Though previous studies have documented various clinical outcomes after cervical arthroplasty for degenerative cervical disc disease, none of them reported the impact of cervical arthroplasty on severe cervical disc degeneration (CDD).

METHODS

This retrospective cohort study included severe 40 CDD (C3-C7) patients who underwent single-level cervical arthroplasty using ProDisc-C between January 2017 and December 2019. After surgical intervention, the range of motion (ROM) was determined, whereas clinical outcomes were measured in terms of the Visual Analogue Scale (VAS) and Neck Disability Index (NDI) to evaluate neck pain and disability, respectively.

RESULTS

Compared to the mean preoperative ROM (6.57 ± 4.85°), the cervical dynamic ROM was increased 3 months after cervical arthroplasty, and the increment was maintained for at least 1 year. The increased ROM is attributed to the extension and not flexion components. The mean preoperative ROM of 6.57 ± 4.85° significantly increased to 11.67 ± 4.98° (P = 0.0005), 10.05 ± 5.18° (P = 0.0426) and 10.46 ± 4.73° (P = 0.0247) after 3 months, 6 months and 1 year, respectively. The extension ROM also revealed a similar trend. VAS for neck and arm decreased from 7.4 and 6.6 to 1.4 and 1.2, respectively. Consistently, the preoperative mean Neck Disability Index (NDI) score of 27.6 decreased to 14.6. We recorded a case of device subsidence, but without extrusion.

CONCLUSIONS

Cervical arthroplasty can improve clinical outcomes and restore ROM in severe CDD patients.

Quality assessment of systematic reviews of surgical treatment of cervical spine degenerative diseases: an overview

OBJECTIVE

To gather all systematic reviews of surgical treatment of degenerative cervical diseases and assess their quality, conclusions and outcomes.

METHODS

A literature search for systematic reviews of surgical treatment of degenerative cervical diseases was conducted. Studies should have at least one surgical procedure as an intervention. Included studies were assessed for quality through Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) and Assessment of Multiple Systematic Reviews (AMSTAR) questionnaires. Quality of studies was rated accordingly to their final score as very poor (<30%), poor (30%-50%), fair (50%-70%), good (70%-90%), and excellent (>90%). If an article reported a conclusion addressing its primary objective with supportive statistical evidence for it, they were deemed to have an evidence-based conclusion.

RESULTS

A total of 65 systematic reviews were included. According to AMSTAR and PRISMA, 1.5% to 6.2% of studies were rated as excellent, while good studies counted for 21.5% to 47.7%. According to AMSTAR, most studies were of fair quality (46.2%), and 6.2% of very poor quality. Mean PRISMA score was 70.2%, meaning studies of good quality. For both tools, performing a meta-analysis significantly increased studies scores and quality. Cervical spondylosis studies reached highest scores among diseases analyzed. Authors stated conclusions for interventions compared in 70.7% of studies, and only two of them were not supported by statistical evidence.

CONCLUSION

Systematic reviews of surgical treatment of cervical degenerative diseases present "fair" to "good" quality in their majority, and most of the reported conclusions are supported by statistical evidence. Including a meta-analysis significantly increases the quality of a systematic review.

A Randomized Control Trial Comparing Local Autografts and Allografts in Single Level Anterior Cervical Discectomy and Fusion Using a StandAlone Cage

Study Design

Randomized controlled trial.

Purpose

To compare the functional and radiological outcomes of anterior cervical discectomy and fusion (ACDF) using local graft and allograft

Overview of Literature

The choice of bone grafts for ACDF varies among different types: iliac crest, allograft, and substitutes. Availability, cost, and donor site morbidity are potential disadvantages. Local osteophyte grafts are then advantageous and shows to have good fusion.

Methods

We randomly sampled participants requiring a single level ACDF for degenerative conditions (n=27) between allograft (n=13) and local graft (n=14) groups. Follow-up of patients occurred at 6 weeks, 3 months, 6 months, and 1 year using Numerical Pain Rating Scale (NPRS) scores for arm and neck pain, Neck Disability Index (NDI), 2-item Short Form Health Survey (SF-12), and lateral disk height. We then assessed radiological fusion using computed tomography (CT) scan at 12 months, and graded as F− (no fusion), F (fusion seen through the cage), F+ (fusion seen through the cage, with bridging bone at one lateral edge), and F++ (fusion seen through cage with bridging bone bilaterally).

Results

There were no significant differences in the age, sex, duration of intervention, blood loss, and hospital stay between the two groups (p>0.05). Both groups showed significant improvements in all functional outcome scores including NPRS for arm and neck pain, NDI, and SF-12 at each visit (p<0.01). We observed a marked improvement in disk height in both groups (p<0.05), but at 1 year of follow-up, there was a significant though slight subsidence (p=0.47). CT at 1 year showed no non-unions. We recorded F, F+, and F++ grades of fusion in 23.2%, 38.4%, and 38.4% in allograft group and 28.6%, 42.8%, and 28.6% in local graft group, respectively, though no significant differences observed (p=0.73).

Conclusions

Marginal osteophytes are effective as graft inside cages for ACDF, since they provide similar radiological outcomes, and equivalent improvements in functional outcomes, as compared to allografts.

Surgical techniques for degenerative cervical spine in Finland from 1999 to 2015

Purpose

The purpose of this study is to assess the trends and regional variations in the operative techniques used for degenerative or rheumatoid cervical spine disease in Finland between 1999 and 2015.

Methods

The Finnish Hospital Discharge Register (FHDR) was searched for the data on all the primary operations for degenerative cervical spine disease (DCSD) or rheumatoid atlanto-axial subluxation (rAAS). Operative codes were used to identify the patients from the FHDR and combined with diagnosis codes to verify patient inclusion. The patients were classified into three groups: anterior cervical decompression and fusion (ACDF), posterior decompression and fusion (PDF) and decompression.

Results

A total of 19,701 primary operations were included. The adjusted incidence of ACDF rose from 6.5 to 27.3 operations/100,000 adults. ACDF became the favoured technique in all the diagnostic groups except AAS, and by 2015, ACDF comprised 84.5% of the operations. The incidence of PDF for DCSD increased from 0.2 to 0.7/100,000 people. Solely decompressive operations declined from 13.7 to 4.0 operations/100,000 people. The regional differences in the incidence of operations were most marked in the incidence of ACDF, with overall incidences ranging from 11.2 to 37.0 operations/100,000. The distribution of the operative techniques used varied as well.

Conclusions

Between 1999 and 2015, the operative techniques used for DCSD changed from prevalently decompressive to utilising ACDF in 68.8 to 91.0% of the operations, depending on the treating hospital. ACDF became the most commonly applied technique for all degenerative diagnoses except AAS.

Electronic supplementary material

The online version of this article (10.1007/s00701-019-04026-9) contains supplementary material, which is available to authorized users.

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.

Cervical disc replacement - emerging equivalency to anterior cervical discectomy and fusion

PURPOSE

Cervical disc replacement has become an acceptable alternative to anterior cervical fusion for the surgical treatment of cervical spine spondylosis resulting in radiculopathy or myelopathy following anterior discectomy and decompression. This concise overview considers the current state of knowledge regarding the continued debate of the role of cervical disc replacement with an update in light of the latest clinical trial results.

METHODS

A literature review was performed identifying clinical trials pertaining to the use of cervical disc replacement compared to cervical discectomy and fusion. Single level disease and two level disease were considered. Outcome data from the major clinical trials was reviewed and salient points identified.

RESULTS

With lengthier follow-up data becoming available, the equivalence of CDR in appropriately selected cases is becoming clear. This is chiefly manifested by reduced re-operation rates and reduced incidence of adjacent level disease in those treated with arthroplasty.

CONCLUSION

Cervical disc replacement shows emerging equivalence in outcomes compared to the gold standard anterior cervical discectomy and fusion. Further longer term results are anticipated to confirm this trend.

Total disc arthroplasty versus anterior cervical interbody fusion: use of the Spine Tango registry to supplement the evidence from randomized control trials

BACKGROUND CONTEXT

Several randomized controlled trials (RCTs) have compared patient outcomes of anterior (cervical) interbody fusion (AIF) with those of total disc arthroplasty (TDA). Because RCTs have known limitations with regard to their external validity, the comparative effectiveness of the two therapies in daily practice remains unknown.

PURPOSE

This study aimed to compare patient-reported outcomes after TDA versus AIF based on data from an international spine registry.

STUDY DESIGN AND SETTING

A retrospective analysis of registry data was carried out.

PATIENT SAMPLE

Inclusion criteria were degenerative disc or disc herniation of the cervical spine treated by single-level TDA or AIF, no previous surgery, and a Core Outcome Measures Index (COMI) completed at baseline and at least 3 months' follow-up. Overall, 987 patients were identified.

OUTCOME MEASURES

Neck and arm pain relief and COMI score improvement were the outcome measures.

METHODS

Three separate analyses were performed to compare TDA and AIF surgical outcomes: (1) mimicking an RCT setting, with admission criteria typical of those in published RCTs, a 1:1 matched analysis was carried out in 739 patients; (2) an analysis was performed on 248 patients outside the classic RCT spectrum, that is, with one or more typical RCT exclusion criteria; (3) a subgroup analysis of all patients with additional follow-up longer than 2 years (n=149).

RESULTS

Matching resulted in 190 pairs with an average follow-up of 17 months that had no residual significant differences for any patient characteristics. Small but statistically significant differences in outcome were observed in favor of TDA, which are potentially clinically relevant. Subgroup analyses of atypical patients and of patients with longer-term follow-up showed no significant differences in outcome between the treatments.

CONCLUSIONS

The results of this observational study were in accordance with those of the published RCTs, suggesting substantial pain reduction both after AIF and TDA, with slightly greater benefit after arthroplasty. The analysis of atypical patients suggested that, in patients outside the spectrum of clinical trials, both surgical interventions appeared to work to a similar extent to that shown for the cohort in the matched study. Also, in the longer-term perspective, both therapies resulted in similar benefits to the patients.

ProDisc-C Total Disc Replacement Versus Anterior Cervical Discectomy and Fusion for Single-Level Symptomatic Cervical Disc Disease: Seven-Year Follow-up of the Prospective Randomized U.S. Food and Drug Administration Investigational Device Exemption Study

BACKGROUND

In patients with single-level cervical degenerative disc disease, total disc arthroplasty can relieve radicular pain and preserve functional motion between two vertebrae. We compared the efficacy and safety of cervical total disc arthroplasty with that of anterior cervical discectomy and fusion (ACDF) for the treatment of single-level cervical degenerative disc disease between C3-C4 and C6-C7.

METHODS

Two hundred and nine patients at thirteen sites were randomly treated with either total disc arthroplasty with ProDisc-C (n = 103) or with ACDF (n = 106). Patients were assessed preoperatively; at six weeks and three, six, twelve, eighteen, and twenty-four months postoperatively; and then annually until seven years postoperatively. Outcome measures included the Neck Disability Index (NDI), the Short Form-36 (SF-36), postoperative neurologic parameters, secondary surgical procedures, adverse events, neck and arm pain, and satisfaction scores.

RESULTS

At seven years, the overall follow-up rate was 92% (152 of 165). There were no significant differences in demographic factors, follow-up rate, or patient-reported outcomes between groups. Both procedures were effective in reducing neck and arm pain and improving and maintaining function and health-related quality of life. Neurologic status was improved or maintained in 88% and 89% of the patients in the ProDisc-C and ACDF groups, respectively. After seven years of follow-up, thirty secondary surgical procedures had been performed in nineteen (18%) of 106 patients in the ACDF group compared with seven secondary surgical procedures in seven (7%) of 103 patients in the ProDisc-C group (p = 0.0099). There were no significant differences in the rates of any device-related adverse events between the groups.

CONCLUSIONS

Total disc arthroplasty with ProDisc-C is a safe and effective surgical treatment of single-level symptomatic cervical degenerative disc disease. Clinical outcomes after total disc arthroplasty with ProDisc-C were similar to those after ACDF. Patients treated with ProDisc-C had a lower probability of subsequent surgery, suggesting that total disc arthroplasty provides durable results and has the potential to slow the rate of adjacent-level disease.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Quality of systematic reviews: an example of studies comparing artificial disc replacement with fusion in the cervical spine

Cervical artificial disc replacement (C-ADR) is now an alternative to anterior cervical discectomy and fusion (ACDF). Many studies have evaluated the efficacy of C-ADR compared with ACDF. This led to a series of systematic reviews and meta-analyses to evaluate the evidence of the superiority of one intervention against the other. The aim of the study presented here was to evaluate the quality of these reviews and meta-analyses. Medline via Ovid, Embase, and Cochrane Library were searched using the keywords: (total disk replacement, prosthesis, implantation, discectomy, and arthroplasty) AND (cervical vertebrae, cervical spine, and spine) AND (systematic reviews, reviews, and meta-analysis). Screening and data extraction were conducted by two reviewers independently. Two reviewers then assessed the quality of the selected reviews and meta-analysis using 11-item AMSTAR score which is a validated measurement tool to assess the methodological quality of systematic reviews. Screening of full reports of 46 relevant abstracts resulted in the selection of 15 systematic reviews and/or meta-analyses as eligible for this study. The two reviewers' inter-rater agreement level was high as indicated by kappa of >0.72. The AMSTAR score of the reviews ranged from 3 to 11. Only one study (a Cochrane review) scored 100% (AMSTAR 11). Five studies scored below (AMSTAR 5) indicating low-quality reviews. The most significant drawbacks of reviews of a score below 5 were not using an extensive search strategy, failure to use the scientific quality of the included studies appropriately in formulating a conclusion, not assessing publication bias, and not reporting the excluded studies. With a significant exception of a Cochrane review, the methodological quality of systematic reviews evaluating the evidence of C-ADR versus ACDF has to be improved.

Anterior Cervical Spine Surgery for Degenerative Disease: A Review

Anterior cervical spine surgery is an established surgical intervention for cervical degenerative disease and high success rate with excellent long-term outcomes have been reported. However, indications of surgical procedures for certain conditions are still controversial and severe complications to cause neurological dysfunction or deaths may occur. This review is focused mainly on five widely performed procedures by anterior approach for cervical degenerative disease; anterior cervical discectomy, anterior cervical discectomy and fusion, anterior cervical corpectomy and fusion, anterior cervical foraminotomy, and arthroplasty. Indications, procedures, outcomes, and complications of these surgeries are discussed.

Minimum 4-year outcomes of cervical total disc arthroplasty versus fusion: a meta-analysis based on prospective randomized controlled trials

The prevalence of cervical disc disease is high, and the traditional surgical method of anterior cervical discectomy and fusion (ACDF) carries with it the disadvantages of motion loss at the operated level, and accelerated adjacent level disc degeneration. Preliminary results of the efficacy and reoperative rate comparing TDA versus ACDF have been reported; however, the long-term outcomes of TDA versus ACDF still remain a topic of debate. This review was prepared following the standard procedures set forth by the Cochrane Collaboration organization, and preferred reporting items for systematic reviews and meta-analyses (PRISMA). The only studies included were randomized controlled trials with a minimum of 4 years of follow-up data. The meta-analysis included the neck disability index (NDI), visual analog scale (VAS) of neck and arm pain, SF-36 physical component scores (SF-36 PCS), over success, neurological success, work status, implant-related complications, and secondary surgery events. Four randomized controlled trials meet the inclusion criteria. The long-term improvement of NDI, VAS of neck and arm pain, SF-36 PCS, over success, and neurological success favored the TDA group. The TDA group also had a lower incidence of secondary surgery for both the index level (RR: 0.45 [0.28, 0.72]) and adjacent level (RR: 0.53 [0.33, 0.88]). In this meta-analysis of 4 included RCTs with a minimum 4 years of follow-ups, total disc arthroplasty showed improvements over ACDF as measured by the NDI, VAS of neck and arm pain, and SF-36 PCS.

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

Background

When surgically treating cervical degenerative disc disease, the most commonly performed procedure is anterior cervical discectomy. This procedure is performed with, or without fusion promoting methods. For both options the rate of fusion is high and there is much debate whether fusion of the treated segment is a contributing factor to accelerated degeneration of adjacent motion segments. In an effort to prevent degeneration of adjacent segments (ASDeg) due to loss of mobility at the operated level, cervical disc arthroplasty (CDA) was introduced. To evaluate the effectiveness of CDA in preventing ASDeg long term studies are necessary. However, prevention of ASDeg is based on the premise that mobile disc prostheses preserve cervical spine motion in a physiological way. In this article the authors describe a short term protocol for a study that aims to investigate whether CDA reaches the intended goal: restoration or preservation of physiological cervical spine motion. To this end, a technique is used to establish the sequence of contributions of cervical motion segments to flexion/extension of the spine.

Methods

24 subjects between 18 and 55 years old, with radicular symptoms due to a herniated disc between C5 and C7, refractory to conservative therapy are randomized to simple discectomy, or CDA. These groups are preceded by a pilot group of three subjects receiving CDA. Fluoroscopic flexion-extension recordings are acquired preoperatively, and at three and 12 months postoperative. At these same time points, patient reported outcomes are collected, and a neurological examination is performed by and independent physician.

Discussion

Studies investigating arthroplasty determine mobility by measuring segmental range of motion (sROM), which gives no information other than presence, and quantity, of mobility. SROM suffer from high variability. The authors therefore chose to use a method previously used in healthy controls, to describe the dynamic process of cervical spine motion in more detail. Determining cervical spine motion patterns has been reported to be more consistent than sROM. If a physiological motion pattern is absent after surgery in the CDA group, prevention of future ASDeg is less likely. Radiological outcomes will be correlated to clinical outcomes.

Trial Registration

NCT00868335

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-015-0479-4) contains supplementary material, which is available to authorized users.

Minimally invasive versus open surgery for cervical and lumbar discectomy: a systematic review and meta-analysis

INTRODUCTION

Minimally invasive surgery for discectomy may accelerate recovery and reduce pain, but it also requires technical expertise and is associated with increased risks. We performed a meta-analysis to determine the effects of minimally invasive versus open surgery on functional outcomes, pain, complications and reoperations among patients undergoing cervical or lumbar discectomy.

METHODS

We searched MEDLINE, Embase and the Cochrane Library for reports of relevant randomized controlled trials published to Jan. 12, 2014. Two reviewers assessed the eligibility of potential reports and the risk of bias of included trials. We analyzed functional outcomes and pain using standardized mean differences (SMDs) that were weighted and pooled using a random-effects model.

RESULTS

We included 4 trials in the cervical discectomy group (n = 431) and 10 in the lumbar discectomy group (n = 1159). Evidence overall was of low to moderate quality. We found that minimally invasive surgery did not improve long-term function (cervical: SMD 0.11, 95% confidence interval [CI] -0.09 to 0.31; lumbar: SMD 0.04, 95% CI -0.11 to 0.20) or reduce long-term extremity pain (cervical: SMD -0.21, 95% CI -0.52 to 0.10; lumbar: SMD 0.08, 95% CI -0.16 to 0.32) compared with open surgery. The evidence suggested overall higher rates of nerve-root injury (risk ratio [RR] 1.62, 95% CI 0.45 to 5.84), incidental durotomy (RR 1.56, 95% CI 0.80 to 3.05) and reoperation (RR 1.48, 95% CI 0.97 to 2.26) with minimally invasive surgery than with open surgery. Infections were more common with open surgery than with minimally invasive surgery (RR 0.24, 95% CI 0.04 to 1.38), although the difference was not statistically significant.

INTERPRETATION

Current evidence does not support the routine use of minimally invasive surgery for cervical or lumbar discectomy. Well-designed trials are needed given the lack of high-quality evidence.

Measurement of intervertebral cervical motion by means of dynamic x-ray image processing and data interpolation

Accurate measurement of intervertebral kinematics of the cervical spine can support the diagnosis of widespread diseases related to neck pain, such as chronic whiplash dysfunction, arthritis, and segmental degeneration. The natural inaccessibility of the spine, its complex anatomy, and the small range of motion only permit concise measurement in vivo. Low dose X-ray fluoroscopy allows time-continuous screening of cervical spine during patient's spontaneous motion. To obtain accurate motion measurements, each vertebra was tracked by means of image processing along a sequence of radiographic images. To obtain a time-continuous representation of motion and to reduce noise in the experimental data, smoothing spline interpolation was used. Estimation of intervertebral motion for cervical segments was obtained by processing patient's fluoroscopic sequence; intervertebral angle and displacement and the instantaneous centre of rotation were computed. The RMS value of fitting errors resulted in about 0.2 degree for rotation and 0.2 mm for displacements.