Clinical and Radiological Outcome of a New Total Cervical Disc Replacement Design

Reasons for Revision Surgery After Cervical Disk Arthroplasty Based on Medical Device Reports Maintained by the US Food and Drug Administration

STUDY DESIGN

Retrospective database review.

OBJECTIVE

The aim of this study was to analyze revisions of CDAs reported to the MAUDE database.

SUMMARY OF BACKGROUND DATA

Cervical disk arthroplasty (CDA) has emerged as a motion-preserving alternative to anterior cervical discectomy and fusion (ACDF) for degenerative cervical disease, demonstrating comparable outcomes. Despite the availability of variable CDA designs, there is limited data on the specific complications of individual CDAs. The Drug Administration's Manufacturer and User Facility Device Experience (MAUDE) database has been used to systematically report complications associated with CDAs. However, data on specific reasons for CDA revision remains scarce. The purpose of this study is to compare common complications associated with revision for different CDAs.

METHODS

The MAUDE database was queried from January 2005 to September 2023, including all nine FDA-approved CDAs. The full-text reports of each complication were categorized based on whether revision surgery was performed, the complications and the type of CDA collected and compared.

RESULTS

A total of 678 revisions for nine CDAs were reported: Mobi-C (239), M6 (167), Prodisc-C (88), Prestige (60), PCM (44), Bryan (35), Secure (23), Simplify (21), and Discover (1). The top three complications associated with revision were migration (23.5%), neck pain (15.5%), and heterotopic ossification (6.6%). The most common complications per device were migration for Mobi-C (26.4%), Prodisc-C (21.3%), Prestige (24.6%), PCM (84.1%), Bryan (48.6%), Secure (30.4%), and Discover (100%). For M6, the most common complications associated with revision surgery were osteolysis (18.6%) and neck pain (18.6%), while neck pain (23.8%) was the most common for the Simplify.

CONCLUSIONS

The MAUDE database highlights complications related to CDA revision in which the primary complications consistently include implant migration, neck pain, and heterotopic ossification, varying in their rerelvance depending on the CDA.

LEVEL OF EVIDENCE

Level II.

Clinical management of bone loss in cervical total disc arthroplasty: literature review and treatment recommendations

PURPOSE

Cervical total disc replacement (cTDR) has been established as an alternative treatment for degenerative cervical radiculopathy and myelopathy. While the rate of complications for cTDR is reasonably low, recent studies have focused on bone loss after cTDR. The purpose of this work is to develop a clinical management plan for cTDR patients with evidence of bone loss. To guide our recommendations, we undertook a review of the literature and aimed to determine: (1) how bone loss was identified/imaged, (2) whether pre- or intraoperative assessments of infection or histology were performed, and (3) what decision-making and revision strategies were employed.

METHODS

We performed a search of the literature according to PRISMA guidelines. Included studies reported the clinical performance of cTDR and identified instances of cervical bone loss.

RESULTS

Eleven case studies and 20 cohort studies were reviewed, representing 2073 patients with 821 reported cases of bone loss. Bone loss was typically identified on radiographs during routine follow-up or by computed tomography (CT) for patients presenting with symptoms. Assessments of infection as well as histological and/or explant assessment were sporadically reported. Across all reviewed studies, multiple mechanisms of bone loss were suspected, and severity and progression varied greatly. Many patients were reportedly asymptomatic, but others experienced symptoms like progressive pain and paresthesia.

CONCLUSION

Our findings demonstrate a critical gap in the literature regarding the optimal management of patients with bone loss following cTDR, and treatment recommendations based on our review are impractical given the limited amount and quality evidence available. However, based on the authors' extensive clinical experience, close follow-up of specific radiographic observations and serial radiographs to assess the progression/severity of bone loss and implant changes are recommended. CT findings can be used for clinical decision-making and further follow-up care. The pattern and rate of progression of bone loss, in concert with patient symptomatology, should determine whether non-operative or surgical intervention is indicated. Future studies involving implant retrieval, histopathological, and microbiological analysis for patients undergoing cTDR revision for bone loss are needed.

Could the different surgical goals of fusion and non-fusion also be achieved in combination within the same patient? Clinical and radiological outcome of hybrid cervical spine surgery

PURPOSE

Hybrid cervical spine surgery (HS) is a novel surgical strategy wherein an artificial disc replacement is done with a cervical fusion nearby with a stand-alone titanium cage to combine the advantages in both procedures. The aim of this study was to evaluate interactions of these devices within the same patient, and to analyze, if the different goal of each implant is accomplished.

METHODS

Thirty-six patients were treated surgically within a non-randomized retrospective study framework with HS. Patients were examined preoperatively followed by clinical and radiological examination at least one year postoperative. Clinical outcome was detected with NDI, VAS arm/neck, pain self-assessment questionnaires and subjective patient satisfaction. Radiological assessments included RoM, segmental lordosis, cervical lordosis of C2-C7, subsidence, ap-migration and heterotopic ossifications (HO) at the cTDR levels.

RESULTS

Statistically significant improvement of all clinical scores was observed (NDI 37.5 to 5.76; VASarm 6.41 to 0.69; VASneck 6.78 to 1.48). Adequate RoM was achieved at cTDR levels. RoM in the ACDF levels was reduced statistically significant (p < 0.001), and solid fusion (> 2°) was achieved in all evaluated fusion level. Global lordosis (C2-C7) increased statistically significant (2.4° to 8.1°). Subsidence and HO at the cTDR levels did not occur.

CONCLUSIONS

HS results in preservation of the segmental motion in the cTDR and fast and solid fusion in the cage cohort simultaneously. Patient safety was proven. In carefully selected cases, HS is a safe and viable treatment option by choosing the right "philosophy" level per level.

Short-term and Long-term Complications of Cervical Disc Arthroplasty

STUDY DESIGN

A narrative review.

OBJECTIVE

This review discusses the short and long-term complications associated with cervical disc arthroplasty (CDA).

SUMMARY OF BACKGROUND DATA

CDA is a safe and effective motion-sparing alternative to fusion for the treatment of cervical disc pathology in patients with cervical radiculopathy or myelopathy. Although CDA offers advantages over fusion within a narrower set of indications, it introduces new technical challenges and potential complications.

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 from January 2005 to August 2023 to identify published studies and clinical trials evaluating cervical disc replacement complications and outcomes.

RESULTS

Short-term complications are primarily related to surgical approach and include dysphagia reported as high as ~70%, laryngeal nerve injury ~0%-1.25%, Horner syndrome ~0.06%, hematoma ~0.01%, gross device extrusion ~0.3%, whereas long-term complications include adjacent segment disease reported at ~3.8%, osteolysis ~44%-64%, heterotopic ossification ~7.3%-69.2%, implant failure ~3.3%-3.7%, and implant wear, which varies depending on design.

CONCLUSIONS

Approaches for mitigating complications broadly include meticulous dissection, intraoperative techniques, and diligent postoperative follow-up. This review emphasizes the need for a comprehensive understanding and management of complications to enhance the safety, reproducibility, and success of CDA. As CDA continues to evolve, there remains a critical need for ongoing research to delve deeper into evaluating risk for complications and long-term patient outcomes.

[Comparison of short-term effectiveness of Prodisc-C Vivo artificial disc replacement and Zero-P fusion for treatment of single-segment cervical spondylosis]

Objective

To compare the short-term effectiveness and the impact on cervical segmental range of motion using Prodisc-C Vivo artificial disc replacement and Zero-P fusion for the treatment of single-segment cervical spondylosis.

Methods

The clinical data of 56 patients with single-segment cervical spondylosis who met the selection criteria between January 2015 and December 2018 were retrospectively analyzed, and they were divided into study group (27 cases, using Prodisc-C Vivo artificial disc replacement) and control group (29 cases, using Zero-P fusion) according to different surgical methods. There was no significant difference between the two groups in terms of gender, age, type of cervical spondylosis, disease duration, involved segments and preoperative pain visual analogue scale (VAS) score, Japanese Orthopaedic Association (JOA) score, neck disability index (NDI), surgical segments range of motion, upper and lower adjacent segments range of motion, overall cervical spine range of motion, and cervical curvature (P>0.05). The operation time, intraoperative blood loss, postoperative hospitalization stay, time of returning to work, clinical effectiveness indicators (VAS score, JOA score, NDI, and improvement rate of each score), and imaging indicators (surgical segments range of motion, upper and lower adjacent segments range of motion, overall cervical spine range of motion, and cervical curvature, prosthesis position, bone absorption, heterotopic ossification, etc.) were recorded and compared between the two groups.

Results

There was no significant difference in operation time and intraoperative blood loss between the two groups (P>0.05); the postoperative hospitalization stay and time of returning to work in the study group were significantly shorter than those in the control group (P<0.05). Both groups were followed up 12-64 months, with an average of 26 months. There was no complication such as limb or organ damage, implant failure, and severe degeneration of adjacent segments requiring reoperation. The VAS score, JOA score, and NDI of the two groups at each time point after operation significantly improved when compared with those before operation (P<0.05); there was no significant difference in the above scores at each time point after operation between the two groups (P>0.05); there was no significant difference in the improvement rate of each score between the two groups at last follow-up (P>0.05). The surgical segments range of motion in the study group maintained to varying degrees after operation, while it in the control group basically disappeared after operation, showing significant differences between the two groups (P<0.05). At last follow-up, there was no significant difference in the upper and lower adjacent segments range of motion in the study group when compared with preoperative ones (P>0.05), while the upper adjacent segments range of motion in the control group increased significantly (P<0.05). The overall cervical spine range of motion and cervical curvature of the two groups decreased at 3 months after operation, and increased to varying degrees at last follow-up, but there was no significant difference between groups and within groups (P>0.05). At last follow-up, X-ray films and CT examinations showed that no prosthesis loosening, subsidence, or displacement was found in all patients; there were 2 cases (7.4%) of periprosthetic bone resorption and 3 cases (11.1%) of heterotopic ossification which did not affect the surgical segments range of motion.

Conclusion

Both the Prodisc-C Vivo artificial disc replacement and Zero-P fusion have satisfactory short-term effectiveness in treatment of single-segment cervical spondylosis. Prodisc-C Vivo artificial disc replacement can also maintain the cervical spine range of motion to a certain extent, while reducing the occurrence of excessive motion of adjacent segments after fusion.

Failure in cervical total disc arthroplasty: single institution experience, systematic review of the literature, and proposal of the RUSH TDA failure classification system

BACKGROUND CONTEXT

Cervical total disc arthroplasty (TDA) is an alternative procedure to anterior cervical discectomy and fusion that facilitates neural decompression while both preserving motion of the spinal unit and decreasing the risk for degenerative changes at adjacent segments. However, due to its more recent introduction in clinical practice and low complication rates, the modes by which TDA may fail remain to be described.

PURPOSE

This study sought to identify the modes and frequencies of cervical TDA failure in order to propose a novel classification system.

STUDY DESIGN

Retrospective cohort and systematic review.

PATIENT SAMPLE

Patients who underwent single or two-level TDA for cervical radiculopathy or myelopathy at a single institution and in the literature of medium and large prospective studies.

OUTCOME MEASURES

Cervical TDA failure, defined as subsequent surgical intervention at the index segment.

METHODS

This study retrospectively reviewed patients who underwent single or two-level TDA for cervical radiculopathy or myelopathy at a single institution to identify the potential implant failure modes. A systematic review and meta-analysis of prospective data in the literature was then performed to further supplement failure mode identification and to describe the rates at which the various failure types occurred. Statistical analysis included between-group comparisons of Non-Failed and Failed patients and frequencies of each failure type among Failed patients.

RESULTS

A retrospective review at our institution of 169 patients (201 levels) identified eight failures, for a failure rate of 4.7%. Additionally, seven patients were revised who had the primary surgery at an outside institution. The systematic review of 3976 patients (4525 levels) identified 165 (4.1%) additional failures. Using this data, six primary failure types were classified, with several subtypes. These include recurrent or persistent index-level stenosis (Type I); migration (Type II) presenting as gross extrusion (A) or endplate failure with subsidence/acute fracture (B); instability (Type III) due to mechanical loosening (A), septic loosening (B), or device fracture (C); device motion loss (Type IV) such as "locking" of the device in kyphosis; implantation error (Type V) due to malposition (A) or improper sizing (B); and wear (Type VI) either without osteolysis (A) or with wear-particle-induced osteolysis (B). Stenosis (Type I) was the most common mode of failure found both through retrospective review and in the literature.

CONCLUSIONS

Cervical TDA fails through six primary mechanisms. While rates of certain failures requiring subsequent surgical intervention are low, it is possible that these complications may become more prevalent upon further longitudinal observation. Thus, future application and validation of this classification system is warranted to evaluate how failure frequencies change over time and with larger patient samples.

Single-level Cervical Arthroplasty with Prodisc-C Vivo Artificial Disc: Five-year Follow-up Results From One Center

STUDY DESIGN

Retrospective study.

OBJECTIVE

The aim of this study was to evaluate the long-term clinical and radiographic outcomes of cervical arthroplasty using the ProDisc-C Vivo prosthesis.

SUMMARY OF BACKGROUND DATA

Previous reports have shown that cervical arthroplasty with ProDisc-C artificial disc has acceptable clinical outcomes at 5-year and 10-year follow-ups.

METHODS

Clinical and radiographic evaluations, including dynamic flexion-extension lateral images, were performed at baseline and at the 5-year follow-up.

RESULTS

Twenty-eight patients who underwent single-level ProDisc-C Vivo arthroplasty were followed-up for a mean period of 65 months. The range of motion at the operated level was 8.9° ± 2.3° at baseline and 8.3° ± 4.8° at the final follow-up (P  = 0.494). Fourteen of 28 levels (50%) developed heterotopic ossification (HO). According to McAfee's classification, one level was classified as grade I, nine levels as grade II, two levels as grade III, and two levels as grade IV. Only four of 28 levels (14.3%) had severe HO. Among patients with cervical spondylotic myelopathy, mJOA score was 13.9 ± 2.5° at baseline and 15.9° ± 1.0° at the final follow-up (P  = 0.001 < 0.05). Among patients with cervical spondylotic radiculopathy, Visual Analog Scale (VAS) neck and shoulder was 5.4 ± 1.4° at baseline and 0.7° ± 1.2° at the final follow-up (p = 0.000 < 0.05), VAS arm was 5.1 ± 2.8° at baseline and 0.5° ± 1.2° at the final follow-up (P  = 0.000 < 0.05). A total of 49 adjacent segments were observed and 13 (26.5%) had adjacent segment degeneration. No patient developed recurrent cervical radiculopathy or myelopathy due to adjacent segment disease. No patient underwent re-operation.

CONCLUSION

ProDisc-C Vivo arthroplasty had satisfactory clinical and radiographic outcomes at 5-year follow-up.Level of Evidence: 4.

Cervical Disc Arthroplasty Migration Following Mechanical Intubation: A Case Presentation and Review of the Literature

BACKGROUND

Cervical arthroplasty has established itself as a safe and efficacious alternative to fusion in management of symptomatic cervical degenerative disease. Recent literature has indicated a trend toward decreased risk of reoperation with cervical arthroplasty, and reoperation in this subset commonly occurs secondary to recurrent pain and device-related complications. The instance of cervical arthroplasty migration, particularly in the setting of trauma, is particularly rare. Here, we report the first case of implant migration secondary to iatrogenic trauma following neck manipulation during direct laryngoscopy for mechanical intubation.

CASE DESCRIPTION

A 53-year-old smoker with cervical spondylosis underwent a cervical 3/4 arthroplasty with a ProDisc-C implant. About a month postoperatively, he was intubated via direct laryngoscopy for community acquired pneumonia and began experiencing new dysphonia and dysphagia after extubation. Delayed imaging revealed anterior migration of the implant. The patient immediately underwent removal of the implant and conversion to anterior cervical discectomy and fusion.

CONCLUSIONS

Supraphysiologic forces exerted through neck manipulation in mechanical intubation mimicked low-energy trauma, and in the setting of ligamentous resection necessary for cervical arthroplasty and inadequate osseous integration, led to migration of the implant. We recommend the integration of fiberoptic technique or video laryngoscopy with manual in line stabilization for intubation of post cervical arthroplasty patients when airway management is necessary within 10 months after cervical arthroplasty. Clinicians and anesthesiologists should have a high clinical suspicion for prompt and early workup with spine imaging in the setting of persistent postintubation symptoms such as dysphonia and/or dysphagia.

Implant Design and the Anchoring Mechanism Influence the Incidence of Heterotopic Ossification in Cervical Total Disc Replacement at 2-year Follow-up

STUDY DESIGN

A nonrandomized, prospective, and single-center clinical trial.

OBJECTIVE

The aim of this study was to determine whether the prosthesis design, and especially changes in the primary anchoring mechanism between the keel-based ProDisc C and the spike-based ProDisc Vivo, affects the frequency of heterotopic ossification (HO) formation over time.

SUMMARY OF BACKGROUND DATA

The occurrence of motion-restricting HO as well as underlying risk factors has so far been a widely discussed, but not well understand phenomenon. The anchoring mechanism and the opening of the anterior cortex may be possible causes of this unwanted complication.

METHODS

Forty consecutive patients treated with the ProDisc C and 42 consecutive patients treated with the ProDisc Vivo were compared with respect to radiological and clinical outcome, with 2 years of follow-up. Clinical outcome scores included the Neck Disability Index (NDI), Visual Analogue Scale (VAS), and arm and neck pain self-assessment questionnaires. Radiological outcomes included the segmental lordosis and range of motion (ROM) of the index-segment as well as the occurrence of HO.

RESULTS

The clinical outcome parameters improved in both groups significantly. [ProDisc C: VAS arm and neck pain from 6.3 and 6.2 preoperatively to 0.7 and 1.3; NDI from 23.0 to 3.7; ProDisc Vivo: VAS arm and neck pain from 6.3 and 4.9 to 1.4 and 1.6, NDI from 34.1 to 8.7; 2-year follow-up (FU)]. The ProDisc Vivo cohort demonstrated a significantly lower incidence of HO than the ProDisc C group at 1-year FU (P = 0.0005) and 2-year FU (P = 0.005). Specifically, high-grade HO occurred in 9% versus 31%.

CONCLUSION

These findings demonstrate that prosthesis designs that allow primary anchoring without violation of the cortical surface help to reduce the incidence of severe ossification, possibly affecting the functionality and mobility of the artificial disc device over of time.

LEVEL OF EVIDENCE

3.

Normal intervertebral segment rotation of the subaxial cervical spine: An in vivo study of dynamic neck motions

Background

Accurate knowledge of the intervertebral center of rotation (COR) and its corresponding range of motion (ROM) can help understand development of cervical pathology and guide surgical treatment.

Methods

Ten asymptomatic subjects were imaged using MRI and dual fluoroscopic imaging techniques during dynamic extension-flexion-extension (EFE) and axial left-right-left (LRL) rotation. The intervertebral segment CORs and ROMs were measured from C34 to C67, as the correlations between two variables were analyzed as well.

Results

During the EFE motion, the CORs were located at 32.4 ± 20.6%, -2.4 ± 11.7%, 21.8 ± 12.5% and 32.3 ± 25.5% posteriorly, and the corresponding ROMs were 13.8 ± 4.3°, 15.1 ± 5.1°, 14.4 ± 7.0° and 9.2 ± 4.3° from C34 to C67. The ROM of C67 was significantly smaller than other segments. The ROMs were not shown to significantly correlate to COR locations (r = −0.243, p = 0.132). During the LRL rotation cycle, the average CORs were at 85.6 ± 18.2%, 32.3 ± 25.3%, 15.7 ± 12.3% and 82.4 ± 31.3% posteriorly, and the corresponding ROMs were 3.5 ± 1.7°, 6.9 ± 3.8°, 9.6 ± 4.1° and 2.6 ± 2.5° from C34 to C67. The ROMs of C34 and C67 was significantly smaller than those of C45 and C56. A more posterior COR was associated with a less ROM during the neck rotation (r = −0.583, p < 0.001). The ROMs during EFE were significantly larger than those during LRL in each intervertebral level.

Conclusion

The CORs and ROMs of the subaxial cervical intervertebral segments were segment level- and neck motion-dependent during the in-vivo neck motions.

The translational potential of this article

Our study indicates that the subaxial cervical intervertebral CORs and ROMs were segment level- and neck motion-dependent. This may help to improve the artificial disc design as well as surgical technique by which the neck functional motion is restored following the cervical arthroplasty.