Usefulness of anterior cervical fusion using titanium interbody cage for treatment of cervical degenerative disease with preoperative segmental kyphosis

Titanium versus polyetheretherketone versus structural allograft in anterior cervical discectomy and fusion: A systematic review

Introduction

Anterior cervical discectomy and fusion (ACDF) is a common procedure to address cervical spine pathology. The most common grafts used are titanium, polyetheretherketone (PEEK), or structural allograft. Comparison of fusion rate is difficult due to non-standardized methods of assessment. We stratified studies by method of fusion assessment and performed a systematic review of fusion rates for titanium, PEEK, and allograft.

Research question

Which of the common implants used in ACDF has the highest reported rate of fusion?

Materials and methods

An experienced librarian performed a five-database systematic search for published articles between 01/01/1990 and 08/07/2021. Studies performed in adults with at least 1 year of radiographic follow up were included. The primary outcome was the rate of fusion. Fusion criteria were stratified into 6 classes based upon best practices.

Results

34 studies met inclusion criteria. 10 studies involving 924 patients with 1094 cervical levels, used tier 1 fusion criteria and 6 studies (309 patients and 367 levels) used tier 2 fusion criteria. Forty seven percent of the studies used class 3–6 fusion criteria and were not included in the analysis. Fusion rates did differ between titanium (avg. 87.3%, range 84%–100%), PEEK (avg. 92.8%, range 62%–100%), and structural allograft (avg. 94.67%, range 82%–100%).

Discussion and conclusion

After stratifying studies by fusion criteria, significant heterogeneity in study design and fusion assessment prohibited the performance of a meta-analysis. Fusion rate did not differ by graft type. Important surgical goals aside from fusion rate, such as degree of deformity correction, could not be assessed. Future studies with standardized high-quality methods of assessing fusion, are required.

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Anterior cervical discectomy and fusion (ACDF) is a common procedure to address cervical spine pathology.

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The optimal graft type of promote fusion is unknown. The methods for assessing fusion are not standardized.

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This is a systematic review comparing fusion rates for ACDF grafts after first stratified by method of fusion assessment.

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Significant heterogeneity in study design and fusion assessment prohibited the performance of a meta-analysis; Fusion rate did not differ by graft type.

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Future studies with standardized high-quality methods of assessing fusion, are required.

Comparison of Outcomes Between Cage Materials Used for Patients Undergoing Anterior Cervical Discectomy and Fusion with Standalone Cages: A Systematic Review and Meta-Analysis

INTRODUCTION

Interbody cages are currently being used to address diseases of the vertebra requiring surgical stabilization. Titanium cages were first introduced in 1988. Polyetheretherketone (PEEK) cages are used frequently as one of the alternatives to titanium cages in current practice. This study aimed to compare available cage materials by reviewing the surgical and radiographic outcomes following anterior cervical discectomy and fusion.

METHODS

A comprehensive search of several electronic databases was conducted following the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. Baseline characteristics, operative outcomes, arthrodesis rates, subsidence rates, and complications were collected from included studies. Collected outcomes were further stratified according to the procedure type, the number of levels operated, and graft used to compare cage materials.

RESULTS

Following the screening for inclusion criteria, a total of 37 studies with 2363 patients were included. The median age was 49.5 years and the median follow-up was 26 months. Overall, no significant differences were found between PEEK and titanium cages regarding fusion, neurologic deficit, subsidence rates, or "good and excellent" outcome according to Odom criteria. However, the standalone comparison between PEEK, titanium, and poly-methyl-methacrylate (PMMA) cages showed a significantly lower fusion rate for PMMA (PEEK: 94%, PMMA: 56%, titanium: 95%, P < 0.01).

CONCLUSIONS

In the present systematic review and meta-analysis, a comparison of the long-term patient-reported and the radiographic outcomes associated with the use of titanium and PEEK, intervertebral body cages showed similar findings. However, there were significantly lower fusion rates for PMMA cages when using a standalone cage without graft material.

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.

Structural Allograft Versus PEEK Implants in Anterior Cervical Discectomy and Fusion: A Systematic Review

STUDY DESIGN

Systematic literature review.

OBJECTIVE

Our primary objective was to compare reported fusion rates after anterior cervical discectomy and fusion (ACDF) using structural allograft versus polyetheretherketone (PEEK) interbody devices in patients with cervical spine degeneration. Our secondary objectives were to compare differences in rates of subsidence and reoperation and in patient-reported outcomes between the 2 groups.

METHODS

Through a systematic review of the English-language literature using various databases, we identified 4702 articles. After we applied inclusion and exclusion criteria, 14 articles (7 randomized controlled trials, 4 prospective studies, and 3 retrospective studies) reporting fusion rates of structural allograft or PEEK interbody devices were eligible for our analysis. No randomized controlled trials compared outcomes of structural allograft versus PEEK interbody devices. Extracted data included authors, study years, study designs, sample sizes, patient ages, duration of follow-up, types of interbody devices used, fusion rates, definition of fusion, reoperation rates, subsidence rates, and patient-reported outcomes.

RESULTS

Fusion rates were 82% to 100% for allograft and 88% to 98% for PEEK interbody devices. The reported data were insufficient to perform meta-analysis. Structural allograft had the highest reported rate of reoperation (14%), and PEEK interbody devices had the highest reported subsidence rate (18%). Patient-reported outcomes improved in both groups. There was insufficient high-quality evidence to compare the associations of various PEEK modifications with fusion rates.

CONCLUSION

Fusion rates were similar between structural allograft and PEEK interbody devices when used for ACDF for cervical spine degeneration. Currently, there is insufficient high-quality evidence to assess associations of PEEK modifications with fusion rates.

LEVEL OF EVIDENCE

II.

[Comparison of the long-term outcomes of total arthroplasty and anterior spinal fusion in the treatment of cervical degenerative disc disease: a metaanalysis]

AIM

The study aim was to perform a meta-analysis based on the results of randomized clinical trials comparing long-term outcomes of total intervertebral disc arthroplasty (TA) and anterior cervical spinal fusion (ACSF) in the surgical treatment of cervical degenerative disc disease.

MATERIAL AND METHODS

We searched Pubmed, EMBASE, ELibrary, and Cochrane Library databases for randomized clinical trials reported between 2008 and August 2018. The relative risk and 95% confidence interval were calculated for dichotomous variables; for continuous variables, we used the standardized mean difference and their 95% CI with application of a random effects model.

RESULTS

The metaanalysis involved 9 randomized controlled clinical trials including the long-term outcomes of surgical treatment in 2,439 patients. A pooled analysis of the data showed that regression of neurological symptoms (p<0.00001), improvement in the quality of life of patients (Neck Disability Index), and lower pain severity (visual analogue scale for upper extremities) were significantly more often observed (p=0.02) in the group of TA patients. In addition, the TA technique was characterized by a statistically significantly lower rate of re-surgery (p<0.0005) and degeneration of the superjacent segment (p<0.0001), with the rate of adverse events being slightly increased (p=0.04).

CONCLUSION

Compared to anterior cervical spinal fusion, TA of cervical intervertebral discs is characterized by significantly better clinical efficacy in patients with cervical degenerative disc disease in the long-term postoperative follow-up.