Category: TDA

Posted on

Cervical disc arthroplasty versus fusion: measuring the burden of recovery

Neurosurgery. 2026;99(3):643-653

The outcome of cervical surgery encompasses not only the patient’s condition at one year, but also the disability experienced while recovering. Asada and colleagues examine this distinction by comparing cervical disc replacement with anterior cervical discectomy and fusion using a cumulative, model-based outcome measure. Their findings associate arthroplasty with a lower burden of neck-related disability during the first postoperative year, without a corresponding advantage in cumulative arm pain. This approach adds a useful dimension to preoperative counseling, although its observational design and the limited validation of the new measure require a cautious interpretation.

Objective

To develop and internally evaluate a modified integrated health state (mIHS) measure and compare cumulative postoperative disability after one- or two-level cervical disc replacement (CDR) and anterior cervical discectomy and fusion (ACDF) for degenerative cervical radiculopathy.

Methods

The authors retrospectively analyzed a prospectively collected, multisurgeon institutional registry covering February 2016 to September 2024. Of 1,273 screened patients, 327 were included: 159 underwent ACDF and 168 underwent CDR. Hybrid constructs, procedures involving three or more levels, missing baseline Neck Disability Index (NDI) scores and baseline NDI below 20 were excluded. The cohort flowchart also excluded myelopathy and trauma.

NDI and neck and arm pain scores were collected before surgery and at intervals through 12 months. Postoperative scores were normalized to baseline, and nonlinear mixed-effects models estimated recovery trajectories. The mIHS summarized the area under these modeled trajectories; it is not a conventional NDI point score. Propensity-score overlap weighting balanced measured baseline characteristics. Patients with shorter follow-up remained eligible, with missing postoperative observations handled under a missing-at-random assumption.

Main results

The one-year NDI-based mIHS was lower after CDR than ACDF (2.68 versus 3.71; difference 1.03, 95% CI 0.80-1.25; p < 0.001), corresponding to a 27.7% relative reduction in this modeled measure. Cumulative neck pain also favored CDR; cumulative arm pain did not differ significantly. Two-level CDR had a similar mIHS to one-level CDR, whereas two-level ACDF carried greater cumulative disability than one-level ACDF. These results describe recovery burden, not a 27.7% reduction in the conventional NDI score.

Interpretation – operative relevance

For patients in whom both procedures are appropriate, the findings support discussing the course of recovery alongside the expected endpoint. Preserved segmental motion after CDR offers a plausible explanation, but this study does not establish it as the cause of better recovery. Nor does it justify extending arthroplasty indications, choosing a particular prosthesis or altering decompression technique. The practical contribution is to procedure selection and counseling rather than a new operative maneuver or proof of long-term superiority.

Limitations

Treatment was not randomized. Before weighting, CDR patients were younger and differed in comorbidity, pathology and number of treated levels. Statistical adjustment cannot remove unmeasured confounding, including the reasons a surgeon selected one procedure over another. Postoperative analgesic consumption was not reliably captured.

Excluding low baseline NDI scores limits applicability to patients with milder disability. Model-based estimates depend on assumptions about recovery trajectories and missing data. The mIHS underwent internal validation only, and its minimum clinically important difference remains undefined; statistical separation therefore cannot be equated with an established patient-perceived benefit threshold.

Follow-up was limited to one year. Imaging was incomplete and nonstandardized, making fusion, motion and heterotopic ossification analyses vulnerable to selection bias. The study does not establish comparative long-term revision rates or device-specific safety.

Clinical takeaway

When counseling suitable candidates for cervical arthroplasty or ACDF, discuss how recovery may unfold, not simply the expected one-year result. This study associates CDR with less cumulative neck-related disability, but its novel outcome measure and observational design do not support a universal preference for arthroplasty.

Posted on

Outcomes after cervical disc replacement compared with anterior cervical discectomy and fusion at medium- to long-term follow-up

Neurosurg Focus 61(1):E5, 2026

This retrospective propensity score–matched analysis of 18,916 adults compares long-term functional and surgical outcomes after cervical disc replacement (CDR) versus anterior cervical discectomy and fusion (ACDF) using a large federated EHR network. Results across 6 months to 5 years show consistently lower risks after CDR for anterior reoperation, posterior revision, adjacent segment disease, new-onset cervical pain, ADL dependence, and surgical site infections.

The study emphasizes durable biomechanical advantages of motion-preserving CDR, with sustained reductions in opioid use and functional impairment at 5 years, while acknowledging limitations of EHR-based retrospective study design, potential selection bias, and absence of granular radiographic and patient-reported outcome data.

Objective Compare long-term functional and clinical outcomes of cervical disc replacement (CDR) versus anterior cervical discectomy and fusion (ACDF) for degenerative cervical disc disease, focusing on whether motion preservation reduces adjacent segment disease and reoperation.

Methods Queried TriNetX EHR network for adults (≥18) undergoing CDR or ACDF for degenerative indications; performed 1:1 propensity score matching and assessed outcomes from 6 months to 5 years, including Kaplan–Meier analyses for reoperation/adjacent segment disease.

Cohort After matching, 9458 patients were included in each group (mean age 48 years).

Reoperation & pain Across follow-up time points, CDR was associated with lower risk of anterior reoperation (RR 0.62, 95% CI 0.52–0.74) and new-onset cervical pain (RR 0.64, 95% CI 0.55–0.73) versus ACDF.

Infection At 1-, 2-, and 5-year follow-ups, CDR showed lower surgical site infection risk (RR 0.62, 95% CI 0.48–0.78).

Sagittal alignment No difference between groups in coding for acquired cervical kyphosis/lordosis after 2 years (p > 0.05).

Opioids (5-year) At 5 years, CDR was associated with lower opioid use (RR 0.66, 95% CI 0.54–0.82).

Conclusion & caution Results suggest superior long-term outcomes with CDR versus ACDF, but interpretation should be cautious due to limitations of retrospective EHR-based analyses; CDR is presented as a viable alternative for degenerative cervical pathologies.

Posted on

Multiple-level (≥ 3) cervical artificial disc replacement: illustrative case and systematic review of the literature

Neurosurg Focus 61(1):E8, 2026

This systematic review and illustrative case evaluate outcomes of multilevel (≥3 levels) cervical artificial disc replacement (C-ADR), synthesizing data from five studies and one clinical example to assess pain relief, functional recovery, range-of-motion preservation, complications, and reoperation rates. The review reports consistent, durable improvements in VAS and NDI scores, preserved segmental and global cervical motion, low revision rates, and primarily transient complications across 3- and 4-level cohorts.

The article compares multilevel C-ADR with anterior cervical discectomy and fusion (ACDF), emphasizing motion-preserving biomechanical advantages that may reduce adjacent segment degeneration. Limitations include sparse, mostly retrospective data, heterogeneous reporting, and limited long-term follow-up, prompting a call for larger prospective trials and extended surveillance for implant longevity and ASD risk.

Objective Characterize outcomes and complications after multilevel (≥ 3 levels) cervical artificial disc replacement (C-ADR), including an illustrative 3-level case for technical discussion.

Methods Systematic review conducted per PRISMA guidelines, querying PubMed and MEDLINE (August 2025) for primary peer-reviewed studies reporting ≥ 3-level C-ADR outcomes, including range of motion (ROM) preservation and complications.

Clinical outcomes Across 5 studies of 3- and 4-level C-ADR, patients had substantial, durable improvements in pain, disability, and quality of life (e.g., neck/arm VAS decreases > 50%) with benefits reported up to 7 years.

Motion preservation Multilevel C-ADR preserved segmental and global cervical ROM, contrasting with near-complete loss of motion reported after multilevel fusion comparators.

Adjacent segment disease No cases of symptomatic adjacent segment degeneration requiring reoperation were reported in the reviewed multilevel C-ADR studies.

Complications/reoperation Complication rates were low and mostly transient; reoperation was required in only 0%–2% of cases across included studies.

Illustrative case A 50-year-old man with progressive cervical myeloradiculopathy underwent 3-level C-ADR (C4–5, C5–6, C6–7) with uncomplicated recovery, immediate symptom relief, and return to unrestricted activity by 6 weeks with preserved motion at 6 months.

Conclusions/limitations 3- and 4-level C-ADR appears safe and effective for appropriately selected patients with durable pain relief and low revision rates, but evidence remains limited (only five stratified studies; largely retrospective) and devices are not FDA-approved for ≥ 3 levels.

Posted on

Randomized controlled trials comparing cervical disc arthroplasty and anterior cervical discectomy and fusion outcomes in degenerative spine disease: a systematic review and meta-analysis

J Neurosurg Spine 43:703–716, 2025

This systematic review and meta-analysis synthesizes randomized controlled trials comparing cervical disc arthroplasty (CDA) with anterior cervical discectomy and fusion (ACDF) for degenerative cervical disc disease. Across 25 RCTs (4530 patients), CDA demonstrated higher overall and neurological success, reduced adjacent-segment disease and fewer reoperations, but increased heterotopic ossification and longer operative times.

The authors performed multilevel meta-analysis and meta-regression to explore heterogeneity, finding myelopathy inclusion and follow-up completeness influenced results; sensitivity analyses excluding industry-funded trials showed consistent findings. Conclusions emphasize CDA’s potential benefits for selected patients while recommending longer-term and subgroup-specific trials.

Cervical Disc Arthroplasty (CDA) vs. Anterior Cervical Discectomy and Fusion (ACDF): CDA shows comparable or potentially greater overall and neurological success rates compared to ACDF for degenerative cervical spine disease.

Motion Preservation: CDA preserves cervical spine range of motion at the operated level, while ACDF is associated with loss of motion and potentially increased risk of adjacent segment degeneration (ASD).

Adjacent Segment Disease (ASD): CDA is associated with a significantly lower rate of ASD compared to ACDF, suggesting a protective effect against degeneration of adjacent spinal segments.

Reoperation Rates: CDA results in lower total reoperation rates compared to ACDF, indicating fewer subsequent surgical interventions.

Heterotopic Ossification (HO): CDA has a significantly higher rate of HO, a complication where bone forms in soft tissue, which can potentially reduce the motion-preserving benefit of the procedure.

Operative Time: CDA procedures are associated with significantly longer operative times than ACDF, with no significant difference in blood loss or hospital length of stay between the two techniques.

Pain and Disability Outcomes: No significant differences were found between CDA and ACDF in terms of improvement in arm pain, neck pain, or disability scores (Neck Disability Index) as measured by patient-reported outcomes.

Patient Selection: The benefits of CDA over ACDF are most applicable to patients with 1-2 level degenerative disease, preserved cervical alignment, and no significant instability or deformity; findings may not generalize to more complex cases.

Posted on

Subtemporal Approach for the Treatment of Ruptured and Unruptured Distal Basilar Artery Aneurysms: Is There a Contemporary Use?

Operative Neurosurgery 27:581–596, 2024

Distal basilar artery aneurysms (DBAs) are high-risk lesions for which endovascular treatment is preferred because of their deep location, yet indications for open clipping nonetheless remain. The subtemporal approach allows for early proximal control and direct visualization of critical posterior perforating arteries, especially for posterior-projecting aneurysms. Our objective was to describe our clinical experience with the subtemporal approach for clipping DBAs in the evolving endovascular era.

METHODS: This was a retrospective, single-institution case series of patients with DBAs treated with microsurgery over a 21-year period (2002-2023). Demographic, clinical, and surgical data were collected for analysis.

RESULTS: Twenty-seven patients underwent clipping of 11 ruptured and 16 unruptured DBAs with a subtemporal approach (24 female; mean age 53 years). Ten patients had expanded craniotomies for treatment of additional aneurysms. The aneurysm occlusion rate was 100%. Good neurological outcomes as defined by the modified Rankin Scale score ≤2 and Glasgow Outcome Scale score ≥4 were achieved in 21/27 patients (78%). Two patients died before hospital discharge, one from vasospasm-induced strokes and another from an intraoperative myocardial infarction.

CONCLUSION: These results demonstrate that microsurgical clip ligation of DBAs using the subtemporal approach remains a viable option for complex lesions not amenable to endovascular management.

Posted on

Optimal Implant Sizing Using Machine Learning Is Associated With Increased Range of Motion After Cervical Disk Arthroplasty

Neurosurgery 95:627–633, 2024

Cervical disk arthroplasty (CDA) offers the advantage of motion preservation in the treatment of focal cervical pathology. At present, implant sizing is performed using subjective tactile feedback and imaging of trial cages. This study aims to construct interpretable machine learning (IML) models to accurately predict postoperative range of motion (ROM) and identify the optimal implant sizes that maximize ROM in patients undergoing CDA.

METHODS: Adult patients who underwent CDA for single-level disease from 2012 to 2020 were identified. Patient demographics, comorbidities, and outcomes were collected, including symptoms, examination findings, subsidence, and reoperation. Affected disk height, healthy rostral disk height, and implant height were collected at sequential time points. Linear regression and IML models, including bagged regression tree, bagged multivariate adaptive regression spline, and k-nearest neighbors, were used to predict ROM change. Model performance was assessed by calculating the root mean square error (RMSE) between predicted and actual changes in ROM in the validation cohort. Variable importance was assessed using RMSE loss. Area under the curve analyses were performed to identify the ideal implant size cutoffs in predicting improved ROM.

RESULTS: Forty-seven patients were included. The average RMSE between predicted and actual ROM was 7.6°(range: 5.8-10.1) in the k-nearest neighbors model, 7.8°(range: 6.5-10.0) in the bagged regression tree model, 7.8°(range: 6.210.0) in the bagged multivariate adaptive regression spline model, and 15.8°(range: 14.3-17.5°) in a linear regression model. In the highest-performing IML model, graft size was the most important predictor with RMSE loss of 6.2, followed by age (RMSE loss = 5.9) and preoperative caudal disk height (RMSE loss = 5.8). Implant size at 110% of the normal adjacent disk height was the optimal cutoff associated with improved ROM.

CONCLUSION: IML models can reliably predict change in ROM after CDA within an average of 7.6 degrees of error. Implants sized comparably with the healthy adjacent disk may maximize ROM.

Posted on

Health Care Costs Following Anterior Cervical Discectomy and Fusion or Cervical Disc Arthroplasty

Spine 2024;49:530–535

Study Design. Observational cohort study.

Objective. To describe the postoperative costs associated with both anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA) in the two-year period following surgery.

Summary of Background Data. CDA has become an increasingly common alternative to ACDF for the treatment of cervical disc disorders. Although a number of studies have compared clinical outcomes between both procedures, much less is known about the postoperative economic burden of each procedure.

Materials and Methods. By analyzing a commercial insurance claims database (Marketscan, Merative), patients who underwent one-level or two-level ACDF and CDA procedures between January 1, 2017 and December 31, 2017 were identified and included in the study. The primary outcome was the cost of payments for postoperative management in the two-year period following ACDF or CDA. Identified postoperative interventions included in the study were: (i) physical therapy, (ii) pain medication, (iii) injections, (iv) psychological treatment, and (iv) subsequent spine surgeries.

Results. Totally, 2304 patients (age: 49.0 ± 9.4 yr; male, 50.1%) were included in the study. In all, 1723 (74.8%) patients underwent ACDF, while 581 (25.2%) underwent CDA. The cost of surgery was similar between both groups (ACDF: $26,819 ± 23,449; CDA: $25,954 ± 20,620; P = 0.429). Thirty-day, 90-day, and two-year global costs were all lower for patients who underwent CDA compared with ACDF ($31,024 vs. $34,411, $33,064 vs. $37,517, and $55,723 vs. $68,113, respectively).

Conclusion. Lower two-year health care costs were found for patients undergoing CDA compared with ACDF. Further work is necessary to determine the drivers of these findings and the associated longer-term outcomes.

Posted on

Incidence and Risk Factor of Implant Dislocation After Cervical Disk Arthroplasty: A Retrospective Cohort Analysis of 756 Patients

Neurosurgery 93:330–338, 2023

Implant dislocation after cervical disk arthroplasty (CDA) is obviously a critical complication, but no information about the incidence and associated risk factor has been reported.

OBJECTIVE: To investigate the incidence and risk factor of implant dislocation after CDA by a retrospective cohort analysis.

METHODS: A retrospective review of a consecutive series of CDA performed between January 2009 and March 2021 at a single institution was conducted. Analyses of chart records and radiological data established the incidence and associated risk factor of implant dislocation after CDA. A Kaplan-Meier survival estimation of implant survival was performed.

RESULTS: A total of 756 consecutive patients were included in this analysis. Five patients (0.7%) had a migration and even dropout of the artificial disk. The overall cumulative survival rate of the implant reached approximately 99.3% of the 756 patients. Preoperative kyphosis was significantly related to implant dislocation (P = .016), with an odds ratio of 15.013.

CONCLUSION: The incidence of implant dislocation after CDA is as low as 0.7% or 5/756 patients. Preoperative kyphosis significantly increases the risk of postoperative implant dislocation by a factor of 15. The migrating implants could be revealed on radiographs as early as 0.9 to 1.4 months postoperatively and were revised to anterior cervical diskectomy and fusion within half a year. No new event of implant dislocation occurred half a year postoperatively. The overall cumulative survival rate of the implant reached 99.3% of the 756 patients. In conclusion, CDA remains a safe and reliable procedure.

Posted on

Comparison of clinical outcomes between cervical disc arthroplasty and anterior cervical discectomy and fusion for the treatment of single-level cervical spondylosis: a 10-year follow-up study

The Spine Journal 23 (2023) 361−368

The theoretical advantage of cervical disc arthroplasty includes preserved motion at the cervical level, which may reduce degeneration of the adjacent segments. The long-term follow-up results are still controversial.

PURPOSE: The present study aimed to retrospectively study the long-term efficacy and complications of cervical disc arthroplasty using a single commercially-available device in a single center.

STUDY DESIGN: This was a propensity-score matched cohort study.

PATIENT SAMPLE: This study enrolled 148 single-level cervical degenerative disease patients from January 2009 to March 2012. After 1:1 propensity score matching, 39 patients remained in the ACDF or ACDR groups.

OUTCOME MEASURES: The outcome measures were neurological functions (Neck Disability Index (NDI) and Japan Orthopedic Association (JOA) scores), radiographic evaluations (cervical curvature, operative segment range of motion, degenerative condition of adjacent segments, heterotopic ossification (HO) of the surgical segment), and complications.

METHODS: NDI and JOA scores were used to evaluate patient neurological functions. Cervical curvature (C2-C7 Cobb angle) and operative segment range of motion (ROM) were compared between the two groups. Grading criteria for osteophyte formation were used to evaluate the degenerative condition of adjacent segments. HO after ACDR was graded according to the McAfee grading method.

RESULTS: The average follow-up time was 119.3 §17.2 months. Satisfactory improvements in neurological function were obtained for both the ACDR and ACDF groups. There were no significant differences in VAS or NDI scores between the two groups. In the ACDR group, the ROM of the operative segment increased from 6.7 §4.3˚ before the operation to 8.9 §3.5˚ on the second day after the operation (p<.001). The ROM of the operative segment was 8.1 §4.0˚ at the 1-year follow-up, 7.2 §3.6˚ at the 2-year follow-up, 5.7 §4.5˚ at the 5-year follow-up and 4.3 §3.9˚ at the last follow-up. ASD was more likely to develop in the caudal adjacent segments and progressed with the follow-up time. At the last follow-up, HO was present in 27 patients (69.23%), while high-grade HO (McAfee scores III and IV) was detected in 6 patients (15.38%).

CONCLUSIONS: Through nearly 10 years of follow-up, ACDR was as effective as ACDF for treating single-level degenerative cervical disc disease. However, HO and the role of ACDR in the protection of ASD remains to be further observed and followed up.

Posted on

Long-term results of the NECK trial—implanting a disc prosthesis after cervical anterior discectomy cannot prevent adjacent segment disease

The Spine Journal 23 (2023) 350−360

Motion preserving anterior cervical disc arthroplasty (ACDA) in patients with cervical radiculopathy was introduced to prevent symptomatic adjacent segment disease as compared to anterior cervical discectomy and fusion (ACDF).

PURPOSE: To evaluate the long-term outcome in patients with cervical radiculopathy due to a herniated disc undergoing ACDA, ACDF or ACD (no cage, no plate) in terms of clinical outcome measured by the Neck Disability Index (NDI). Likewise, clinically relevant adjacent segment disease is assessed as a long-term result.

STUDY DESIGN: Double-blinded randomized controlled trial.

PATIENT SAMPLE: A total of 109 patients with one level herniated disc were randomized to one of the following treatments: ACDA, ACDF with intervertebral cage, ACD without cage.

OUTCOME MEASURES: Clinical outcome was measured by patients’ self-reported NDI, Visual Analogue Scale (VAS) neck pain, VAS arm pain, SF36, EQ-5D, perceived recovery and reoperation rate. Radiological outcome was assessed by radiographic cervical curvature and adjacent segment degeneration (ASD) parameters at baseline and up until five years after surgery.

METHODS: To account for the correlation between repeated measurements of the same individual Generalized Estimated Equations (GEE) were used to calculate treatment effects, expressed in difference in marginal mean values for NDI per treatment group.

RESULTS: Clinical outcome parameters were comparable in the ACDA and ACDF group, but significantly worse in the ACD group, though not reaching clinical relevance. Annual reoperation rate was 3.6% in the first two years after surgery, declined to 1.9% in the years thereafter. The number of reoperations for ASD was not lower in the ACDA group, while the number of reoperations at the index level was higher after ACD, when compared to ACDF and ACDA.

CONCLUSIONS: A persisting absence of clinical superiority was demonstrated for the cervical disc prosthesis five years after surgery. Specifically, clinically relevant adjacent level disease was not prevented by implanting a prosthesis. Single level ACD without implanting an intervertebral device provided worse clinical outcome, which was hypothesized to be caused by delayed fusion. This stresses the need for focusing on timely fusion in future research.

Posted on

Longitudinal assessment of segmental motion of the cervical spine following total disc arthroplasty: a comparative analysis of devices

J Neurosurg Spine 37:556–562, 2022

Total disc arthroplasty (TDA) has been shown to be an effective and safe treatment for cervical degenerative disc disease at short- and midterm follow-up. However, there remains a paucity of literature reporting the differences between individual prosthesis designs with regard to device performance. In this study, the authors evaluated the longterm maintenance of segmental range of motion (ROM) at the operative cervical level across a diverse range of TDA devices.

METHODS In this study, the authors retrospectively evaluated all consecutive patients who underwent 1- or 2-level cervical TDA between 2005 and 2020 at a single institution. Patients with a minimum of 6 months of follow-up and lateral flexion/extension radiographs preoperatively, 2 months postoperatively, and at final follow-up were included. Radiographic measurements included static segmental lordosis, segmental range of motion (ROM) on flexion/extension, global cervical (C2–7) ROM on flexion/extension, and disc space height. The paired t-test was used to evaluate improvement in radiographic parameters. Subanalysis between devices was performed using one-way ANCOVA. Significance was determined at p < 0.05.

RESULTS A total of 85 patients (100 discs) were included, with a mean patient age of 46.01 ± 8.82 years and followup of 43.56 ± 39.36 months. Implantations included 22 (22.00%) M6-C, 51 (51.00%) Mobi-C, 14 (14.00%) PCM, and 13 (13.00%) ProDisc-C devices. There were no differences in baseline radiographic parameters between groups. At 2 months postoperatively, PCM provided significantly less segmental lordosis (p = 0.037) and segmental ROM (p = 0.039). At final follow-up, segmental ROM with both the PCM and ProDisc-C devices was significantly less than that with the M6-C and Mobi-C devices (p = 0.015). From preoperatively to 2 months postoperatively, PCM implantation led to a significant loss of lordosis (p < 0.001) and segmental ROM (p = 0.005) relative to the other devices. Moreover, a significantly greater decline in segmental ROM from 2 months postoperatively to final follow-up was seen with ProDiscC, while segmental ROM increased significantly over time with Mobi-C (p = 0.049).

CONCLUSIONS Analysis by TDA device brand demonstrated that motion preservation differs depending on disc design. Certain devices, including M6-C and Mobi-C, improve ROM on flexion/extension from preoperatively to postoperatively and continue to increase slightly at final follow-up. On the other hand, devices such as PCM and ProDisc-C contributed to greater segmental stiffness, with a gradual decline in ROM seen with ProDisc-C. Further studies are needed to understand how much segmental ROM is ideal after TDA for preservation of physiological cervical kinematics.

 

Proudly powered by WordPress