The use of anterior cervical interbody spacer with integrated fixation screws for management of cervical disc disease

A retrospective comparative analysis of anterior cervical discectomy and fusion using stand-alone titanium cage versus cage and plate fixation in two-level cervical disc herniation

BACKGROUND

This study aims to compare the outcomes of two-level anterior cervical discectomy and fusion (ACDF) procedures using stand-alone cages versus cage and plate fixation in patients diagnosed with cervical disc herniation (CDH).

MATERIALS AND METHODS

This retrospective analysis included 60 patients who underwent two-level ACDF procedures. Patients were divided into two groups: one treated with stand-alone cages and the other with cage and plate fixation. Data on surgical duration, blood loss, fusion stability, and complication rates were collected. Clinical outcomes, including neck pain and functional status, were assessed using standard scoring systems.

RESULTS

Plate fixation provided superior fusion stability but was associated with longer surgery durations, higher intraoperative blood loss, and increased complication rates. Stand-alone cages reduced intraoperative trauma but demonstrated higher subsidence rates and prolonged fusion times. Both techniques resulted in significant improvements in neck pain and disability scores.

DISCUSSION

While both approaches are effective for managing cervical disc herniation, each has distinct advantages and limitations. Surgical technique selection should be individualized, considering patient-specific anatomical factors, functional demands, and the risk-benefit profile of each approach.

A systematic review of risk factors and adverse outcomes associated with anterior cervical discectomy and fusion surgery over the past decade

Background

Anterior cervical discectomy and fusion (ACDF) is one of the most frequently performed cervical surgeries in the world, yet there have been several reported complications.

Objective

To determine the actual incidence of complications related to ACDF as well as any risk variables that may have been identified in earlier research.

Methods

To evaluate the origin, presentation, natural history, and management of the risks and the complications, we conducted a thorough assessment of the pertinent literature. An evaluation of clinical trials and case studies of patients who experienced one or more complications following ACDF surgery was done using a PubMed, Cochrane Library, and Google Scholar search. Studies involving adult human subjects that were written in the English language and published between 2012 and 2022 were included in the search. The search yielded 79 studies meeting our criteria.

Results

The overall rates of complications were as follows: Dysphagia 7.9%, psudarthrosis 5.8%, adjacent segment disease (ASD) 8.8%, esophageal perforations (EPs) 0.5%, graft or hardware failure 2.2%, infection 0.3%, recurrent laryngeal nerve palsy 1.7%, cerebrospinal fluid leak 0.8%, Horner syndrome 0.5%, hematoma 0.8%, and C5 palsy 1.9%.

Conclusion

Results showed that dysphagia was a common postoperative sequelae with bone morphogenetic protein use and a higher number of surgical levels being the major risk factors. Pseudarthrosis rates varied depending on the factors such as asymptomatic radiographic graft sinking, neck pain, or radiculopathy necessitating revision surgery. The incidence of ASD indicated no data to support anterior cervical plating as more effective than standalone ACDF. EP was rare but frequently fatal, with no correlation found between patient age, sex, body mass index, operation time, or number of levels.

Trends of single-level anterior cervical discectomy and fusion documentation after the 2015 Centers for Medicare & Medicaid Services coding audit

OBJECTIVE

With the use of anterior cervical discectomy and fusion (ACDF) expected to rise by 13.3% from 2020 to 2040, the increased usage of interbody cages with integral anterior fixation prompted a Centers for Medicare & Medicaid Services (CMS) review, which resulted in coding changes affecting anterior instrumentation documentation. CMS determined that Current Procedural Terminology (CPT) code 22845 should not be used to report integrated instrumentation (plate) with an interbody device, and if additional anterior instrumentation (e.g., plates and screws) is placed with an integrated interbody device, then a 59 modifier should be used. There is sparse literature examining the trends of ACDF without and with additional anterior instrumentation after the 2015 CMS audit. Therefore, this study aimed to evaluate the trends of single-level subaxial ACDF utilization from 2011 to 2019 to determine whether the 2015 CMS audit influenced the documented usage of additional anterior instrumentation.

METHODS

A retrospective cohort study was performed using the commercially available database PearlDiver. Patient records were queried from 2011 to 2019 for single-level subaxial ACDF without (CPT code 22551) and with (CPT codes 22551 + 22845) instrumentation. Cochran-Armitage trend analyses were performed to evaluate the hypothesis that ACDF with additional anterior instrumentation decreased over the given time period.

RESULTS

Between 2011 and 2019, the total number of single-level ACDFs decreased from 6202 to 4402. From 2011 to 2015, an average of 6240 patients per year underwent single-level subaxial ACDF; of those, 950 patients (15.2%) had ACDF without instrumentation and 5290 patients (84.8%) had ACDF with instrumentation. In 2016, the total number of single-level subaxial ACDFs decreased to 5525, with 1006 patients (18.2%) receiving no instrumentation and 4519 patients (81.8%) receiving instrumentation. From 2017 to 2019, an average of 4283 patients per year underwent a single-level subaxial ACDF; of these, 1280 (29.9%) had no instrumentation and 3003 (70.1%) had instrumentation (all p < 0.0001).

CONCLUSIONS

From 2015 to 2019, single-level ACDF without instrumentation significantly increased by 91.5% and ACDF with anterior instrumentation significantly decreased by 18.1%. The 2015 CMS audit of interbody cages and anterior instrumentation coding (CPT code 22845) may account for the decreased documentation of anterior instrumentation in the 9-year period. Understanding CMS auditing could help surgeons perceive changes in practice patterns that may lead to a more thorough evaluation of patient outcomes, cost, and overall value.

Dysphagia as a Postoperative Complication of Anterior Cervical Discectomy and Fusion

Anterior cervical discectomy and fusion (ACDF), despite its possible complications, remains the gold standard for the surgical treatment of patients with radiculopathy and/or myelopathy caused by cervical intervertebral disc herniation or spondylosis. Despite its high rate of incidence, postoperative dysphagia following ACDF is still poorly understood; its pathogenesis remains relatively unknown, and its risk factors are still a subject of debate.

The aim of this study is to review the incidence, pathogenesis, diagnosis, and methods of prevention of dysphagia in ACDF patients. To this end, a literature review was conducted based on the PubMed internet database. Article titles were searched by using the following keywords: “dysphagia” and “anterior cervical discectomy and fusion” or “ACDF”. The search was limited to prospective clinical studies evaluating dysphagia after ACDF surgery. Studies published in non-English languages, retrospective studies, cadaveric studies, reviews, case reports, study protocols, and commentary studies were excluded.

Initially, 335 studies were identified after a primary search. After the application of the exclusion criteria, 73 studies remained for the final analysis. This literature review focused on identifying the rate of dysphagia and the various risk factors leading to this complication by comparing and evaluating the current literature with a wide spectrum of heterogeneity concerning patients, surgeons, and surgical techniques. A mean dysphagia rate of 19.4% (95% CI: 9.6%-29.1%) based on the findings of the included studies correlating dysphagia directly with ACDF procedures was calculated. Various established risk factors leading to dysphagia include the female sex, smoking, the surgical approach, rhBMP-2 use, and multilevel surgery, while zero-profile devices seem to reduce dysphagia risk. The diagnosis is based on clinical and radiological findings, especially prevertebral soft-tissue swelling. However, videofluoroscopic and endoscopic studies have been recently used for the evaluation of dysphagia. The role of local administration of steroids in the prevention of dysphagia has not yet been clarified. This review underscores the prevailing rudimentary understanding of the problem of dysphagia after ACDF procedures and highlights the need for more sensitive, factor-specific studies for understanding the impact of various risk factors on the incidence rate of dysphagia.

Biomechanical Study of Cervical Endplate Removal on Subsidence and Migration in Multilevel Anterior Cervical Discectomy and Fusion

Study Design

This study compares four cervical endplate removal procedures, validated by finite element models.

Purpose

To characterize the effect of biomechanical strength and increased contact area on the maximum von Mises stress, migration, and subsidence between the cancellous bone, endplate, and implanted cage.

Overview of Literature

Anterior cervical discectomy and fusion (ACDF) has been widely used for treating patients with degenerative spondylosis. However, no direct correlations have been drawn that incorporate the impact of the contact area between the cage and the vertebra/endplate.

Methods

Model 1 (M1) was an intact C2C6 model with a 0.5 mm endplate. In model 2 (M2), a cage was implanted after removal of the C4-C5 and C5-C6 discs with preservation of the osseous endplate. In model 3 (M3), 1 mm of the osseous endplate was removed at the upper endplate. Model 4 (M4) resembles M3, except that 3 mm of the osseous endplate was removed.

Results

The range of motion (ROM) at C2C6 in the M2-M4 models was reduced by at least 9º compared to the M1 model. The von Mises stress results in the C2C3 and C3C4 interbody discs were significantly smaller in the M1 model and slightly increased in the M2-M3 and M3-M4 models. Migration and subsidence decreased from the M2-M3 model, whereas further endplate removal increased the migration and subsidence as shown in the transition from M3 to M4.

Conclusions

The M3 model had the least subsidence and migration. The ROM was higher in the M3 model than the M2 and M4 models. Endplate preparation created small stress differences in the healthy intervertebral discs above the ACDF site. A 1 mm embedding depth created the best balance of mechanical strength and contact area, resulting in the most favorable stability of the construct.

Cage-screw and anterior plating combination reduces the risk of micromotion and subsidence in multilevel anterior cervical discectomy and fusion-a finite element study

BACKGROUND CONTEXT

Anterior cervical discectomy and fusion (ACDF) is widely used to treat patients with spinal disorders, where the cage is a critical component to achieve satisfactory fusion results. However, it is still not clear whether a cage with screws or without screws will be the best choice for long-term fusion as the micromotion (sliding distance) and subsidence (penetration) of the cage still take place repeatedly.

PURPOSE

This study aims to examine the effect of cage-screws on the biomechanical characteristics of the human spine, implanted cage, and associate hardware by comparing the micromotion and subsidence.

STUDY DESIGN

A finite element (FE) analysis study.

METHODS

A FE model of a C3-C5 cervical spine with ACDF was developed. The spinal segment was modeled with the removal of the anterior longitudinal ligament (ALL), posterior longitudinal ligament (PLL), and discectomy was then implanted with a cage-screw system. Three models were analyzed: the first was the original spine (S1 model), the second, S2, was implanted with cages and anterior plating, and the third, S3, was implanted with a cage-screw system in addition to the anterior plate. All investigations were under 1 N•m in flexion, extension, lateral bending, and axial rotation situations.

RESULTS

Finite element analysis (FEA) demonstrated that range of motion (ROM) at C3-C4 in the S2 model was significantly reduced more than that in the S3 model, while the ROM at both C4-C5 in the S3 model was reduced more than that in the S2 model in all simulations. The ROM at C3-C5 in the S1 model was reduced by over 5° in the S2 and S3 models in all loading conditions. The micromotion and subsidence at all contacts of C3-C5 in the S3 model were lower than that in the S2 model in all flexion, extension, bending, and axial simulations. The subsidence and micromotion could be seen in the barrier area of the S2 model, while they occurred near the edge of the screw in the S3 model.

CONCLUSIONS

These results showed that the cage-screw and anterior plating combination has promising potential to reduce the risk of micromotion and subsidence of implanted cages in two or more level ACDFs.

CLINICAL SIGNIFICANCE

The use of double segmental fixation with cage-screw anterior plating combination constructs may increase the stiffness of the construct and reduce the incidence of clinical and radiographic pseudarthrosis following multilevel ACDF, which in turn, could decrease the need for revision surgeries or supplemental posterior fixation.