Is single-level cervical disc arthroplasty associated with a lower reoperation rate than anterior cervical discectomy and fusion?

Presented at the 2023 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves

Alexander Tuchman Departments of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, California

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Ida Chen Departments of Orthopedic Surgery, Cedars-Sinai Medical Center, Los Angeles, California

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Corey T. Walker Departments of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, California

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Linda E. Kanim Departments of Orthopedic Surgery, Cedars-Sinai Medical Center, Los Angeles, California

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Hyun W. Bae Departments of Orthopedic Surgery, Cedars-Sinai Medical Center, Los Angeles, California

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David L. Skaggs Departments of Orthopedic Surgery, Cedars-Sinai Medical Center, Los Angeles, California

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OBJECTIVE

Long-term meta-analysis of cervical disc arthroplasty (CDA) trials report lower rates of subsequent cervical spine surgical procedures with CDA compared with anterior cervical discectomy and fusion (ACDF). The objective of this study was to compare the rate of subsequent cervical spine surgery in single-level CDA–treated patients to that of a matched cohort of single-level ACDF–treated patients by using records from 2010 to 2021 included in a large national administrative claims database (PearlDiver).

METHODS

This retrospective matched-cohort study used a large national insurance claims database; 525,510 patients who had undergone a single-level ACDF or CDA between 2010 and 2021 were identified. Patients with other same-day spine procedures, as well as those for trauma, infection, or tumor, were excluded, yielding 148,531 patients. ACDF patients were matched 2:1 to CDA patients on the basis of clinical and demographic characteristics. The primary outcome was the overall incidence of all-cause cervical reoperation after index surgery. Secondary outcomes included readmission, any adverse event within 90 days, and overall reintervention after index surgery. Multivariable logistic regression analyses were adjusted for covariates and were employed to estimate the effect of the index ACDF or CDA procedure on patient outcomes. Survival was assessed using Kaplan-Meier estimation, and differences between ACDF- and CDA-treated patients were compared using log-rank tests.

RESULTS

After the patients were matched, 28,795 ACDF patients to 14,504 CDA patients were included. ACDF patients had higher rates of 90-day adverse events (18.4% vs 14.6%, adjusted odds ratio [aOR] 0.77, 95% CI 0.73–0.82, p < 0.001) and readmission (11.5% vs 9.7%, aOR 0.87, 95% CI 0.81–0.93, p < 0.001). Over a mean 4.3 years of follow-up, 5.0% of ACDF patients and 5.4% of CDA patients underwent reoperation (aOR 1.09, 95% CI 1.00–1.19, p = 0.059). The rate of aggregate reintervention was higher in CDA patients than in ACDF patients (11.7% vs 10.7%, aOR 1.10, p = 0.002). The Kaplan-Meier 10-year reoperation-free survival rate was worse for CDA than ACDF (91.0% vs 92.0%, p = 0.05), as was the rate of reintervention-free survival (81.2% vs 82.0%, p = 0.003).

CONCLUSIONS

Single-level CDA was associated with a similar rate of reoperation and higher rate of subsequent injections when compared with a matched cohort that underwent single-level ACDF. CDA was associated with lower rates of 90-day adverse events and readmissions.

ABBREVIATIONS

ACDF = anterior cervical discectomy and fusion; aOR = adjusted odds ratio; CDA = cervical disc arthroplasty; CPT = Current Procedural Terminology; ECI = Elixhauser Comorbidity Index; ICD = International Classification of Diseases ; IDE = investigational device exemption; RCT = randomized controlled trial.

OBJECTIVE

Long-term meta-analysis of cervical disc arthroplasty (CDA) trials report lower rates of subsequent cervical spine surgical procedures with CDA compared with anterior cervical discectomy and fusion (ACDF). The objective of this study was to compare the rate of subsequent cervical spine surgery in single-level CDA–treated patients to that of a matched cohort of single-level ACDF–treated patients by using records from 2010 to 2021 included in a large national administrative claims database (PearlDiver).

METHODS

This retrospective matched-cohort study used a large national insurance claims database; 525,510 patients who had undergone a single-level ACDF or CDA between 2010 and 2021 were identified. Patients with other same-day spine procedures, as well as those for trauma, infection, or tumor, were excluded, yielding 148,531 patients. ACDF patients were matched 2:1 to CDA patients on the basis of clinical and demographic characteristics. The primary outcome was the overall incidence of all-cause cervical reoperation after index surgery. Secondary outcomes included readmission, any adverse event within 90 days, and overall reintervention after index surgery. Multivariable logistic regression analyses were adjusted for covariates and were employed to estimate the effect of the index ACDF or CDA procedure on patient outcomes. Survival was assessed using Kaplan-Meier estimation, and differences between ACDF- and CDA-treated patients were compared using log-rank tests.

RESULTS

After the patients were matched, 28,795 ACDF patients to 14,504 CDA patients were included. ACDF patients had higher rates of 90-day adverse events (18.4% vs 14.6%, adjusted odds ratio [aOR] 0.77, 95% CI 0.73–0.82, p < 0.001) and readmission (11.5% vs 9.7%, aOR 0.87, 95% CI 0.81–0.93, p < 0.001). Over a mean 4.3 years of follow-up, 5.0% of ACDF patients and 5.4% of CDA patients underwent reoperation (aOR 1.09, 95% CI 1.00–1.19, p = 0.059). The rate of aggregate reintervention was higher in CDA patients than in ACDF patients (11.7% vs 10.7%, aOR 1.10, p = 0.002). The Kaplan-Meier 10-year reoperation-free survival rate was worse for CDA than ACDF (91.0% vs 92.0%, p = 0.05), as was the rate of reintervention-free survival (81.2% vs 82.0%, p = 0.003).

CONCLUSIONS

Single-level CDA was associated with a similar rate of reoperation and higher rate of subsequent injections when compared with a matched cohort that underwent single-level ACDF. CDA was associated with lower rates of 90-day adverse events and readmissions.

In Brief

Researchers used a large administrative database to follow patients longitudinally after single-level cervical disc arthroplasty and anterior cervical discectomy and fusion. In contradiction to the available data from cervical disc replacement randomized control trials, no difference out to 10 years was found in the cervical reoperation rates between the two procedures. This is the largest long-term outcome data study to compare the two procedures as they are actually used in clinical practice.

Anterior cervical discectomy and fusion (ACDF) is a well-established treatment for degenerative cervical myelopathy and radiculopathy with demonstrated safety and efficacy.1,2 Despite good clinical results, it is associated with adjacent-segment pathology and symptomatic pseudarthrosis that often require revision surgery.3,4 Cervical disc arthroplasty (CDA) was developed to preserve motion at the treated level with the intention that this would slow down the development of adjacent-segment pathology and eliminate the risk for pseudarthrosis.5 Multiple prospective randomized controlled trials (RCTs) have demonstrated the noninferiority of CDA when compared with ACDF.611 With long-term follow-up, patients from these RCTs have been found to have lower rates of subsequent cervical spine surgical procedures.1,1214 These results seem to confirm the biomechanical benefits of CDA over fusion.15,16

Between 2010 and 2022, utilization of CDA has increased by greater than 400%.17 As the utilization and indications for CDA continue to expand, the question becomes whether the results from the RCTs can be generalized to less controlled clinical scenarios, as are found in general spine practice throughout the United States.

PearlDiver Patient Records Database (PearlDiver, Inc.) is a nationwide commercial claims database that includes data from over 90 million patients in the United States covered with private insurance and Medicare. Its advantage over other popular administrative databases used in research, such as the National Inpatient Sample and the Medicare claims databases, is that its data span across the continuum of care (inpatient, outpatient, etc.) and across diverse insurance payer types, allowing for tracking of individual patients across all healthcare-associated billing encounters over the lifetime of enrollment in the associated healthcare plan, wherein the unit of observation is the patient. With the PearlDiver database, patients undergoing index single-level CDA or ACDF can be followed longitudinally for the incidence rates of the diagnostic and procedural codes associated with perioperative complications and further interventions. In line with the available long-term RCT data, we hypothesized that the patients queried in the PearlDiver database having undergone single-level CDA versus ACDF would also have lower rates of perioperative complications and subsequent cervical spine surgery.

Methods

Data Source and Study Design

This matched cohort study was a retrospective analysis of insurance claims submitted from 2010 through the first quarter of 2021 inclusive and included in the MOrtho dataset of the PearlDiver database. PearlDiver is a fee-for-service national insurance claims database with patients across private, commercial, and public health networks that uses records from inpatient and outpatient facilities. This study was a secondary analysis of de-identified observational data and was deemed exempt from review by the Cedars-Sinai Medical Center institutional review board. Final analyses were conducted in 2023.

Patient Selection

To identify eligible study subjects, we queried the database using the International Classification of Diseases (ICD) and Current Procedural Terminology (CPT) codes associated with cervical spine surgical procedures. The ICD and CPT codes used for patient identification are provided in Supplemental Table 1. We identified the base population of patients using CPT codes for ACDF (22551 and 22554) and CDA (22856). To isolate single-level ACDF and CDA, patients were excluded if they had a code for a multilevel or other posterior or anterior spine procedure on the same day as their surgery, or if they had undergone any other spine procedure in the 6 months before their surgery. Patients were also excluded if they had a diagnosis code associated with trauma, fracture, spinal cord injury, or infection within 6 months before the index surgery; if they had a diagnosis code associated with an inflammatory condition, tumor, or spinal deformity at any time before the index surgery; or if they did not have continuous enrollment for 90 days after their index surgery. The follow-up duration for each patient was calculated from the day of their index surgery to the last encounter recorded in the database.

Outcomes Assessed

Primary Outcome

The primary outcome was the incidence of reoperation at any point after the index surgery. Reoperation was defined as the occurrence of any subaxial cervical spine procedure after the day of the index surgery. This included a range of surgical interventions that served as indicators of need for additional surgical management.

Secondary Outcomes

The secondary outcomes were the occurrence of readmission and any adverse event within 90 days after surgery. Adverse events included surgical and medical complications, as well as other unanticipated events requiring medical attention or hospitalization.

Cervical injection after index surgery was included in this analysis as a proxy measure of residual or recurrent cervical symptoms that were not severe enough to require surgery, and additionally, to evaluate the use of nonsurgical interventions as part of postoperative care. The final secondary outcome measure was reintervention, a combined variable that included any subaxial cervical procedure consisting of both reoperations and other cervical interventions such as injection. Examining reintervention served to provide a comprehensive view of the need for additional intervention-level treatment after initial surgery.

Covariates

Patient-level demographic data including age, sex, geographic region, insurance plan type, Elixhauser Comorbidity Index (ECI) score, and year of surgery are available from the PearlDiver database and were extracted as covariates of interest. We additionally abstracted myelopathy, comorbid diabetes, comorbid osteoporosis (including osteopenia), and lifetime smoking status from the data using the associated ICD-9/ICD-10 and CPT codes, utilizing methods that have been validated in previous studies.1820 These covariates of interest have been associated with greater rates of perioperative complications, pseudarthrosis, instrumentation failure, and need for reoperation in spinal patients and were thus included in the analyses as potential confounders that could influence surgical outcomes beyond ACDF versus CDA treatment approach.2125

Matching

In addition to ACDF cases outnumbering CDA cases, the ACDF patient population comprises a broader range of patients who may have more variable health status and comorbidities. To account for imbalances in these patient populations, we created one group of ACDF patients and one group of CDA patients that were matched 2:1 in terms of the covariates of age, sex, ECI score, prior osteoporosis diagnosis, and year of surgery. Exact matching was used to create comparable groups by minimizing the variability in these factors that may influence health and treatment outcomes among spinal surgery patients.

Statistical Analysis

Patient demographic and clinical characteristics were described with frequency distributions and summary statistics. Differences in the incidence rates of individual complications and aggregated outcomes were first assessed between the ACDF and CDA groups using univariate analyses. The Student t-test was used to detect differences in continuous variables, whereas the chi-squared or Fisher exact test was used to detect differences in categorical variables. For the primary and secondary outcomes, we conducted multivariable logistic regression analyses and controlled for potential confounding factors. The adjusted multivariable regression model included the following: all matching variables, clinically relevant variables determined a priori to be associated with outcomes, and any unbalanced variables with a standardized difference > 0.10.26 These regression analyses aimed to identify the independent effect of the treatment approach (ACDF vs CDA) on the primary and secondary outcomes. The Kaplan-Meier method was utilized to estimate survival with reoperation and reintervention as endpoints, allowing for the calculation of survival probabilities over time and the assessment of differences in survival between the ACDF and CDA groups by using the log-rank test. All tests were 2-sided, and statistical significance was determined at p < 0.05. Analyses were conducted with R statistical software through the PearlDiver interface and Microsoft Excel version 16.73.

Results

We identified 148,531 eligible patients, of whom 133,472 (89.9%) underwent ACDF and 15,059 (10.1%) underwent CDA between 2010 and of inclusive the first quarter of 2021 (Fig. 1). The unmatched single-level ACDF cohort was significantly older, had a higher proportion of male patients, had a higher mean ECI score, and had higher rates of preoperative smoking, osteoporosis, and diabetes. After 2:1 matching, 28,795 patients who underwent single-level ACDF and 14,504 patients who underwent single-level CDA were included in our analyses. Full baseline demographic and clinical characteristics are described in Table 1. The mean follow-up was longer in the ACDF cohort (5.34 years vs 4.34 years, p < 0.001), but the mean follow-up was equivalent (4.30 years vs 4.33 years, p = 0.255) after matching. Of note, the database interface does not display the frequencies of 10 or fewer patients in any given group to ensure patient privacy.

FIG. 1.
FIG. 1.

Study flow diagram of the included patients.

TABLE 1.

Patient demographic and clinical characteristics: total sample and matched groups

CharacteristicTotalMatched Groups*
ACDF (n = 133,472)CDA (n = 15,059)SMDACDF (n = 28,795)CDA (n = 14,504)SMD
Mean age, yrs53.0 (11.7)45.6 (9.7)−0.03246.1 (9.5)46.0 (9.5)−0.001
Sex
 Female70,186 (52.6)8,280 (55.0)5.6115,832 (55.0)7,970 (55.0)−0.1
 Male63,286 (47.4)6,779 (45.0)−5.6112,963 (45.0)6,534 (45.0)0.1
Geographical region
 Midwest34,988 (26.2)3,828 (25.4)−2.127,635 (26.5)3,711 (25.6)−2.1
 Northeast21,135 (15.8)2,323 (15.4)−1.324,758 (16.5)2,204 (15.2)−3.6
 South62,088 (46.5)5,802 (38.5)−19.0513,307 (46.2)5,580 (38.5)−15.5
 West14,706 (11.0)3,034 (20.1)27.022,940 (10.2)2,941 (20.3)26.6
 Unknown593 (0.4)73 (0.5)0.68165 (0.6)69 (0.5)−1.3
Insurance plan
 Cash256 (0.2)43 (0.3)2.0870 (0.2)40 (0.3)0.6
 Commercial105,573 (79.1)13,365 (88.8)34.4124,310 (84.4)12,881 (88.8)13.0
 Government3,721 (2.8)434 (2.9)0.66905 (3.1)415 (2.9)−1.6
 Medicaid8,543 (6.4)841 (5.6)−4.112,342 (8.1)799 (5.5)−10.6
 Medicare18,936 (14.2)675 (4.5)−50.081,770 (6.1)662 (4.6)−7.1
 Unknown1,174 (0.9)146 (1.0)1.07258 (0.9)138 (1.0)0.6
Year of operation
Comorbidities
 Mean ECI score3.38 (3.03)2.60 (2.49)−0.0582.58 (2.42)2.59 (2.44)0.001
 Smoking status40,129 (30.1)4,027 (26.7)−0.0909,220 (32.0)3,891 (26.8)−0.138
 Osteoporosis10,611 (7.9)688 (4.6)−0.3261,102 (3.8)592 (4.1)0.037
 Diabetes29,381 (22.0)1,844 (12.2)−0.3893,884 (13.5)1,793 (12.4)−0.055
 Myelopathy40,796 (30.6)3,164 (21.0)−0.2787,163 (24.9)3,031 (20.9)−0.125
Mean follow-up, yrs5.34 (3.01)4.34 (2.86)−0.3324.30 (2.80)4.33 (2.80)0.011

SMD = standardized mean difference.

Values are shown as number (%) or mean (SD) unless indicated otherwise.

Study groups were matched by age group, sex, ECI score, osteoporosis, and year of surgery.

Significant at p = 0.001.

Significant at p < 0.01.

Univariate analyses revealed that CDA patients had significantly lower rates of 90-day readmissions and most 90-day complications, including wound complications, surgical site infection, spinal cord injury, dural tear, dysphagia, limb paralysis, pneumonia, renal failure, urinary tract infection, incision, and drainage. The frequencies of perioperative complications in the ACDF and CDA groups are shown in Table 2. Multivariable analysis revealed fewer readmissions within 90 days in the CDA group compared to the ACDF group (adjusted odds ratio [aOR] 0.87, 95% CI 0.81–0.93, p < 0.001). Similarly, CDA patients had a lower rate of having any adverse event in the 90 days after index surgery (aOR 0.77, 95% CI 0.73–0.82 p < 0.001).

TABLE 2.

Comparison of 90-day complications: ACDF versus CDA

ComplicationACDF (n = 28,795)CDA (n = 14,504)p Value
Wound complications621 (2.2)169 (1.2)<0.001
Surgical site infection521 (1.8)117 (0.8)<0.001
Spinal cord injury246 (0.9)18 (0.1)<0.001
Cervical nerve root injury16 (0.1)<11 (<0.08)*0.047
Dural tear54 (0.2)11 (0.1)0.004
Dysphagia870 (3.0)346 (2.4)<0.001
Cervical kyphosis48 (0.2)17 (0.1)0.238
Limb paralysis315 (1.1)36 (0.2)<0.001
Mortality12 (0)<11 (<0.08)*0.809
DVT/pulmonary embolism186 (0.6)50 (0.3)<0.001
Myocardial infarction38 (0.1)15 (0.1)0.469
Respiratory failure222 (0.8)33 (0.2)<0.001
Pneumonia68 (0.2)16 (0.1)0.005
Renal failure118 (0.4)36 (0.2)0.008
Sepsis19 (0.1)<11 (<0.08)*0.839
Urinary tract infection528 (1.8)202 (1.4)<0.001
I&D, exploration, or evacuation437 (1.5)86 (0.6)<0.001
Readmission3,298 (11.5)1,412 (9.7)<0.001
Any adverse event5,287 (18.4)2,119 (14.6)<0.001

DVT = deep vein thrombosis; I&D = incision & drainage.

Values are shown as number (%) unless indicated otherwise.

Because the database interface does not display frequencies of 10 or fewer patients in any given group for patient privacy reasons, these instances are represented as "<11" in this table.

The overall reoperation rate after index surgery, with a mean overall follow-up of 4.3 years, was higher for CDA patients compared with ACDF patients in univariate analysis (5.4% vs 5.0%, p = 0.045). After multivariate analysis, the rates of reoperation were comparable between CDA and ACDF (aOR 1.09, 95% CI 1.00–1.19, p = 0.59). The rate of receipt of subsequent cervical injection, however, was significantly higher in the CDA group compared to the ACDF group (7.8% vs 6.8%, aOR 1.16, 95% CI 1.08–1.26, p < 0.001). The rate of aggregate reintervention was also higher in CDA patients (11.7% vs 10.7%, aOR 1.10, 95% CI 1.04–1.18, p = 0.002). The frequencies and aORs for the primary and secondary outcomes after single-level ACDF and single-level CDA are presented in Table 3. We have also included a complete list of the aORs for the covariates included in the logistic regression (Supplemental Tables 26). These tables detail the effect sizes of all included covariates on the primary and secondary outcomes.

TABLE 3.

aORs for primary and secondary outcomes: ACDF versus CDA (mean follow-up 4.3 years)

OutcomeACDF (n = 28,795)CDA (n = 15,504)Univariate p ValueaOR (95% CI)*Multivariate p Value
Any adverse event (90-day)5,287 (18.4)2,119 (14.6)<0.0010.77 (0.73–0.82)<0.001
Readmission (90-day)3,298 (11.5)1,412 (9.7)<0.0010.87 (0.81–0.93)<0.001
Reop (overall)1,435 (5.0)789 (5.4)0.0451.09 (1.00–1.19)0.059
Injection (overall)1,962 (6.8)1,136 (7.8)<0.0011.16 (1.08–1.26)<0.001
Reintervention (overall)3,088 (10.7)1,695 (11.7)0.0031.10 (1.04–1.18)0.002

Values are shown as number (%) unless indicated otherwise.

The covariates included in the multivariable analysis were age, sex, ECI score, myelopathy, osteoporosis, diabetes, smoking status, insurance plan, and year of surgery.

Kaplan-Meier analyses did not reveal differences between ACDF and CDA in terms of reoperation-free survival at 5 years from reoperation (94.2% vs 93.7%, p > 0.05) but did slightly favor ACDF at 10 years (92.0% vs 91.0%, p = 0.05) (Fig. 2). The ACDF group had better reintervention-free survival at 5 years (87.5% vs 86.4%, p = 0.003) and 10 years (82% vs 81.2%, p = 0.003) than the CDA group (Fig. 3).

FIG. 2.
FIG. 2.

Kaplan-Meier curves of reoperation-free survival in ACDF and CDA patients over 10 years. The rates were as follows: 5 years, 94.2% versus 93.7%, p > 0.05, log-rank test; 10 years, 92.0% versus 91.0%, p = 0.05, log-rank test. Figure is available in color online only.

FIG. 3.
FIG. 3.

Kaplan-Meier curve of reintervention-free survival in ACDF and CDA patients over 10 years. The rates were as follows: 5 years, 87.5% versus 86.4%, p = 0.003, log-rank test; 10 years, 82% versus 81.2%, p = 0.003, log-rank test. Figure is available in color online only.

Discussion

In a real-world billing database, single-level CDA was not associated with a lower all-cause cervical reoperation rate compared with ACDF. This finding persisted out to 10 years in the Kaplan-Meier reoperation-free survival analysis. This finding is in contradiction to the available data from the investigational device exemption (IDE) RCTs for CDA, which generally show lower cervical reoperation rates with CDA.1,1214 The single-level CDA cohort had a significantly higher rate of cervical injections and all-cause cervical reintervention (surgery or injection) after index surgery. Higher reintervention rates after CDA persisted out to 10 years in the Kaplan-Meier reintervention-free survival analysis. We included cervical injections in this analysis to represent a proxy measure of residual or recurrent cervical symptoms that were not severe enough to require surgery. CDA was associated with lower rates of 90-day adverse events and readmission.

There are several factors that could be contributing to the differences in the results between those of the RCTs and our real-world evaluation of CDA. The RCTs for single-level CDA represent some of the highest quality data in spine surgery, and multiple secondary analyses of long-term follow-up and associated meta-analyses have found consistent divergence in reoperation favoring CDA over ACDF between the 4- and 7-year time points.12 These IDE results, with very specific and narrow patient selection, tend to not be reproduced within larger databases that capture CDA as it is truly utilized in clinical practice. Skeppholm et al. reported higher overall cervical reoperation rates after CDA compared with ACDF in their series of 715 patients with at least 5 years of follow-up. They found that CDA was associated with a higher reoperation rate both overall (OR 1.7) and at the index level (OR 5.1).26 Similar to the current study, this study was not a controlled trial and may be more representative of how CDA and ACDF are used in clinical practice, with variability in technique and implants. Unfortunately, due to the constraints of the billing data within the PearlDiver database, we were unable to tell whether the reoperations in our study were related to a higher incidence of index-level surgical procedures versus those for adjacent-segment pathology.

The results from the National Swedish Spine Register also showed a higher reoperation rate for CDA (7.8%) compared with ACDF (3.4%).27 In the National Inpatient Sample, the revision burden, defined as the ratio of revision procedures to the sum of primary and revision procedures, was reported to be over two times higher for CDA (5.9%) compared to ACDF (2.3%).28 However, not all administrative database studies have shown a higher reoperation rate after CDA. Using the MarketScan database, Kumar et al. reported no difference in revision surgical procedures after CDA or ACDF at 5-year follow-up.29 Kelly et al. also found no difference in the reoperation rates at 1, 3, and 5 years postoperatively in a cohort of 1469 CDA patients included in the California Office of Statewide Planning and Development discharge database.30

The original IDE studies were powered to show the noninferiority of CDA compared to ACDF, as well as designed with the intention of obtaining FDA approval.611 Common inclusion and exclusion criteria for the IDE studies and subsequent FDA approval were strict, with inclusion criteria including the following: single- or 2-level disease between C3 and C7, radiculopathy or myelopathy, spondylosis or herniated disc, skeletal maturity, and failure of 6 weeks of conservative treatment. Common exclusion criteria included the following: axial neck pain only, prior cervical spine surgery, more than 2 levels requiring surgery, segmental instability, severe spondylosis, disc height < 3 mm, severe facet arthropathy, significant kyphotic deformity, osteoporosis, or metabolic bone disease.31 In real-world practice, adherence to the strict indications and exclusion criteria likely does not occur. For example, in our series, we found that 4.6% of patients who underwent CDA had a diagnosis of osteoporosis, indicating that at least a portion of the patients who underwent CDA in this study would not have been included in the IDE RCTs. Although the unmatched data found that patients undergoing single-level CDA compared to those undergoing ACDF tended to be younger and have fewer medical comorbidities, this study raises concerns that the real-world patient selection for CDA is contributing to inferior results compared with those published in the RCTs. In our opinion, this highlights the importance of proper patient selection when choosing to use CDA in clinical practice.

Different types of bias may be found in an administrative database study compared with data from prospective RCTs. Administrative databases are subject to limitations based on the accuracy and specificity of the billing codes utilized to define patient cohorts and outcomes. The retrospective design may lead to selection bias that could favor either the CDA or ACDF cohort in terms of the reoperation and reintervention rates. Meanwhile, the study design and goals of the industry-funded IDE studies present a well-defined clinical cohort and outcome measures, but it may not represent true clinical practice.3234 The original studies were designed for noninferiority analysis.611 To overcome the original study design, meta-analysis and long-term follow-up of the patients from the original studies have been used to report the decreased reoperation rate.1,1214 Furthermore, the patients and practitioners involved in most previous studies were not blinded to treatment, thus introducing expectation bias, which may have affected the reoperation rates.35

We found that CDA was associated with a lower rate of 90-day adverse events and readmissions. It is difficult to tell whether this result was related to single-level CDA being a less invasive technique than ACDF or if selection bias could have been involved. We attempted to overcome selection bias by excluding diagnosis codes that would be common exclusion criteria for CDA owing to higher risk for perioperative complications, such as metabolic bone disease, trauma, infection, or tumor, as well as by matching the cohorts. Unfortunately, billing codes are not inclusive of all factors involved with clinical decision-making regarding surgical approach. Although most RCTs report similar rates of adverse events after either procedure, the meta-analysis by Xie et al. found lower overall rates of adverse events favoring CDA, with a risk ratio of 0.72 (95% CI 0.53–0.96).36

There were several limitations to the study. This was a secondary analysis of a large billing database. Although we observed statistically significant differences in several outcomes, it is important to consider that these may have been due to the large sample size. The effect sizes of these differences were relatively small and may not translate to clinically meaningful differences. Furthermore, the database was not designed with the intent of clinical research, and as such there were limitations based on the accuracy and specificity of the billing data. The billing codes do not provide information on the spinal level where the surgery was performed. This limits analysis of index-level versus adjacent-segment pathology. Furthermore, the PearlDiver dataset is not inclusive of all major payers in the United States, so it may not be a perfectly representative cross-section of care within the United States over the study period. For example, the cohort geographically over-represents the South, with nearly 40% of the cases included in this study. It must be noted that statistical limitations of performing a matched analysis can occur; the variables decided for matching were chosen on the basis of our current understanding of potential confounding variables but may not have included all influential variables. PearlDiver limits matching of cohorts to 5 variables, which left some potentially significant differences between the matched ACDF and CDA cohorts. Even after matching, the ACDF cohort had statistically significant higher rates of diabetes, smoking, and noncommercial insurance. It should be noted that this would likely lead to a relatively healthier cohort for CDA, which would strengthen our finding that CDA is not protective for reoperation and increases odds for reintervention. Finally, there were limitations in long-term follow-up related to having only 10 years of continuous data and loss of follow-up when patients changed insurance carriers.

Conclusions

Single-level CDA was associated with a similar rate of reoperation and higher rate of subsequent injections when compared to a matched cohort that underwent single-level ACDF. CDA was associated with lower rates of 90-day adverse events and readmissions. The reoperation findings from this large national database of over 14,000 CDA patients and survival analysis out to 10 years contrasts with the results from the clinical trials of CDA. Further study is needed to evaluate whether the real-world utilization of CDA offers similar long-term results as those reported in the clinical trials. This study contributes to ongoing discourse regarding the complex and nuanced considerations that must be made when translating research findings into the broader clinical context.

Disclosures

Dr. Walker reported teaching consultant fees from Globus outside the submitted work. Dr. Skaggs reported grants from NuVasive as co-principal investigator paid to the Pediatric Spine Foundation; personal consulting and royalty fees from Zimvie and Globus Medical; personal consulting fees from Top Doctors; personal consulting fees from and fees as co-editor in chief of Orthobullets; personal royalty fees from Wolters Kluwer Health and Medtronic; investments from Green Sun Medical; non-financial support for board membership from the Pediatric Spine Foundation and Scoliosis Research Society; non-financial support for medical advisory board membership from Bikur Cholim and Gasol Foundation; and non-financial support for editorial board membership from Spine Deformity, Orthopedics Today, and Journal of Children’s Orthopaedics outside the submitted work; in addition, Dr. Skaggs had a patent for Medtronic issued and a patent for Zimvie issued.

Author Contributions

Conception and design: Tuchman, Bae, Skaggs. Acquisition of data: Tuchman, Chen. Analysis and interpretation of data: all authors. Drafting the article: Tuchman, Chen. Critically revising the article: Tuchman, Walker, Kanim, Bae, Skaggs. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Tuchman. Statistical analysis: Chen, Kanim. Administrative/technical/material support: Tuchman, Chen, Skaggs. Study supervision: Tuchman, Bae, Skaggs.

Supplemental Information

Online-Only Content

Supplemental material is available with the online version of the article.

Previous Presentations

This work was presented at the 2023 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves meeting, Miami, FL, March 16–19, 2023.

References

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    • PubMed
    • Search Google Scholar
    • Export Citation
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    Bohlman HH, Emery SE, Goodfellow DB, Jones PK. Robinson anterior cervical discectomy and arthrodesis for cervical radiculopathy. Long-term follow-up of one hundred and twenty-two patients. J Bone Joint Surg Am. 1993;75(9):12981307.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Hilibrand AS, Carlson GD, Palumbo MA, Jones PK, Bohlman HH. Radiculopathy and myelopathy at segments adjacent to the site of a previous anterior cervical arthrodesis. J Bone Joint Surg Am. 1999;81(4):519528.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Veeravagu A, Cole T, Jiang B, Ratliff JK. Revision rates and complication incidence in single- and multilevel anterior cervical discectomy and fusion procedures: an administrative database study. Spine J. 2014;14(7):11251131.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Shin JJ, Kim KR, Son DW, et al. Cervical disc arthroplasty: what we know in 2020 and a literature review. J Orthop Surg (Hong Kong). 2021;29(1_suppl):23094990211006934.

    • PubMed
    • Search Google Scholar
    • Export Citation
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    Skeppholm M, Lindgren L, Henriques T, Vavruch L, Löfgren H, Olerud C. The Discover artificial disc replacement versus fusion in cervical radiculopathy—a randomized controlled outcome trial with 2-year follow-up. Spine J. 2015;15(6):12841294.

    • PubMed
    • Search Google Scholar
    • Export Citation
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    Coric D, Nunley PD, Guyer RD, et al. Prospective, randomized, multicenter study of cervical arthroplasty: 269 patients from the Kineflex|C artificial disc investigational device exemption study with a minimum 2-year follow-up: clinical article. J Neurosurg Spine. 2011;15(4):348358.

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    • Search Google Scholar
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    Phillips FM, Lee JYB, Geisler FH, et al. A prospective, randomized, controlled clinical investigation comparing PCM cervical disc arthroplasty with anterior cervical discectomy and fusion. 2-year results from the US FDA IDE clinical trial. Spine (Phila Pa 1976). 2013;38(15):E907E918.

    • PubMed
    • Search Google Scholar
    • Export Citation
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    Murrey D, Janssen M, Delamarter R, et al. Results of the prospective, randomized, controlled multicenter Food and Drug Administration investigational device exemption study of the ProDisc-C total disc replacement versus anterior discectomy and fusion for the treatment of 1-level symptomatic cervical disc disease. Spine J. 2009;9(4):275286.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Heller JG, Sasso RC, Papadopoulos SM, et al. Comparison of BRYAN cervical disc arthroplasty with anterior cervical decompression and fusion: clinical and radiographic results of a randomized, controlled, clinical trial. Spine (Phila Pa 1976). 2009;34(2):101107.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11

    Gornet MF, Burkus JK, Shaffrey ME, Argires PJ, Nian H, Harrell FE Jr. Cervical disc arthroplasty with PRESTIGE LP disc versus anterior cervical discectomy and fusion: a prospective, multicenter investigational device exemption study. J Neurosurg Spine. 2015;23(5):558573.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 12

    Badhiwala JH, Platt A, Witiw CD, Traynelis VC. Cervical disc arthroplasty versus anterior cervical discectomy and fusion: a meta-analysis of rates of adjacent-level surgery to 7-year follow-up. J Spine Surg. 2020;6(1):217232.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Zhu RS, Kan SL, Cao ZG, Jiang ZH, Zhang XL, Hu W. Secondary surgery after cervical disc arthroplasty versus fusion for cervical degenerative disc disease: a meta-analysis with trial sequential analysis. Orthop Surg. 2018;10(3):181191.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 14

    Zhong ZM, Zhu SY, Zhuang JS, Wu Q, Chen JT. Reoperation after cervical disc arthroplasty versus anterior cervical discectomy and fusion: a meta-analysis. Clin Orthop Relat Res. 2016;474(5):13071316.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Park J, Shin JJ, Lim J. Biomechanical analysis of disc pressure and facet contact force after simulated two-level cervical surgeries (fusion and arthroplasty) and hybrid surgery. World Neurosurg. 2014;82(6):13881393.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Laxer EB, Darden BV, Murrey DB, et al. Adjacent segment disc pressures following two-level cervical disc replacement versus simulated anterior cervical fusion. Stud Health Technol Inform. 2006;123:488492.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 17

    Gordon AM, Golub IJ, Ng MK, Lam AW, Houten JK, Saleh A. Primary and revision cervical disc arthroplasty from 2010-2020: patient demographics, utilization trends, and healthcare reimbursements. World Neurosurg. 2022;168:e344e349.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 18

    Chen G, Khan N, Walker R, Quan H. Validating ICD coding algorithms for diabetes mellitus from administrative data. Diabetes Res Clin Pract. 2010;89(2):189195.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 19

    Casp AJ, Montgomery SR Jr, Cancienne JM, Brockmeier SF, Werner BC. Osteoporosis and implant-related complications after anatomic and reverse total shoulder arthroplasty. J Am Acad Orthop Surg. 2020;28(3):121127.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20

    Wiley LK, Shah A, Xu H, Bush WS. ICD-9 tobacco use codes are effective identifiers of smoking status. J Am Med Inform Assoc. 2013;20(4):652658.

  • 21

    Maron SZ, Neifert SN, Ranson WA, et al. Elixhauser comorbidity measure is superior to Charlson Comorbidity Index in-predicting hospital complications following elective posterior cervical decompression and fusion. World Neurosurg. 2020;138:e26e34.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 22

    Guzman JZ, Feldman ZM, McAnany S, Hecht AC, Qureshi SA, Cho SK. Osteoporosis in cervical spine surgery. Spine (Phila Pa 1976). 2016;41(8):662668.

  • 23

    Jain N, Labaran L, Phillips FM, et al. Prevalence of osteoporosis treatment and its effect on post-operative complications, revision surgery and costs after multi-level spinal fusion. Global Spine J. 2022;12(6):11191124.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24

    Seicean A, Seicean S, Alan N, et al. Effect of smoking on the perioperative outcomes of patients who undergo elective spine surgery. Spine (Phila Pa 1976). 2013;38(15):12941302.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 25

    Grønkjær M, Eliasen M, Skov-Ettrup LS, et al. Preoperative smoking status and postoperative complications: a systematic review and meta-analysis. Ann Surg. 2014;259(1):5271.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 26

    Skeppholm M, Henriques T, Tullberg T. Higher reoperation rate following cervical disc replacement in a retrospective, long-term comparative study of 715 patients. Eur Spine J. 2017;26(9):24342440.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 27

    MacDowall A, Skeppholm M, Lindhagen L, et al. Artificial disc replacement versus fusion in patients with cervical degenerative disc disease with radiculopathy: 5-year outcomes from the National Swedish Spine Register. J Neurosurg Spine. 2018;30(2):159167.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 28

    Saifi C, Fein AW, Cazzulino A, et al. Trends in resource utilization and rate of cervical disc arthroplasty and anterior cervical discectomy and fusion throughout the United States from 2006 to 2013. Spine J. 2018;18(6):10221029.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 29

    Kumar C, Dietz N, Sharma M, Wang D, Ugiliweneza B, Boakye M. Long-term comparison of health care utilization and reoperation rates in patients undergoing cervical disc arthroplasty and anterior cervical discectomy and fusion for cervical degenerative disc disease. World Neurosurg. 2020;134:e855e865.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 30

    Kelly MP, Eliasberg CD, Riley MS, Ajiboye RM, SooHoo NF. Reoperation and complications after anterior cervical discectomy and fusion and cervical disc arthroplasty: a study of 52,395 cases. Eur Spine J. 2018;27(6):14321439.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 31

    Nunley P, Frank K, Stone M. Patient selection in cervical disc arthroplasty. Int J Spine Surg. 2020;14(s2):S29S35.

  • 32

    Shah RV, Albert TJ, Bruegel-Sanchez V, Vaccaro AR, Hilibrand AS, Grauer JN. Industry support and correlation to study outcome for papers published in Spine. Spine (Phila Pa 1976). 2005;30(9):10991105.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 33

    Singh K, Phillips FM, Park DK, Pelton MA, An HS, Goldberg EJ. Factors affecting reoperations after anterior cervical discectomy and fusion within and outside of a Federal Drug Administration investigational device exemption cervical disc replacement trial. Spine J. 2012;12(5):372378.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 34

    Cher DJ, Capobianco RA. Spine device clinical trials: design and sponsorship. Spine J. 2015;15(5):11331140.

  • 35

    Sundseth J, Fredriksli OA, Kolstad F, et al. The Norwegian Cervical Arthroplasty Trial (NORCAT): 2-year clinical outcome after single-level cervical arthroplasty versus fusion—a prospective, single-blinded, randomized, controlled multicenter study. Eur Spine J. 2017;26(4):12251235.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 36

    Xie L, Liu M, Ding F, Li P, Ma D. Cervical disc arthroplasty (CDA) versus anterior cervical discectomy and fusion (ACDF) in symptomatic cervical degenerative disc diseases (CDDDs): an updated meta-analysis of prospective randomized controlled trials (RCTs). Springerplus. 2016;5(1):1188.

    • PubMed
    • Search Google Scholar
    • Export Citation

Supplementary Materials

  • Collapse
  • Expand
Images from Özer and Demirtaş (pp 351–358).
  • FIG. 1.

    Study flow diagram of the included patients.

  • FIG. 2.

    Kaplan-Meier curves of reoperation-free survival in ACDF and CDA patients over 10 years. The rates were as follows: 5 years, 94.2% versus 93.7%, p > 0.05, log-rank test; 10 years, 92.0% versus 91.0%, p = 0.05, log-rank test. Figure is available in color online only.

  • FIG. 3.

    Kaplan-Meier curve of reintervention-free survival in ACDF and CDA patients over 10 years. The rates were as follows: 5 years, 87.5% versus 86.4%, p = 0.003, log-rank test; 10 years, 82% versus 81.2%, p = 0.003, log-rank test. Figure is available in color online only.

  • 1

    Wang QL, Tu ZM, Hu P, et al. Long-term results comparing cervical disc arthroplasty to anterior cervical discectomy and fusion: a systematic review and meta-analysis of randomized controlled trials. Orthop Surg. 2020;12(1):1630.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2

    Bohlman HH, Emery SE, Goodfellow DB, Jones PK. Robinson anterior cervical discectomy and arthrodesis for cervical radiculopathy. Long-term follow-up of one hundred and twenty-two patients. J Bone Joint Surg Am. 1993;75(9):12981307.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Hilibrand AS, Carlson GD, Palumbo MA, Jones PK, Bohlman HH. Radiculopathy and myelopathy at segments adjacent to the site of a previous anterior cervical arthrodesis. J Bone Joint Surg Am. 1999;81(4):519528.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Veeravagu A, Cole T, Jiang B, Ratliff JK. Revision rates and complication incidence in single- and multilevel anterior cervical discectomy and fusion procedures: an administrative database study. Spine J. 2014;14(7):11251131.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Shin JJ, Kim KR, Son DW, et al. Cervical disc arthroplasty: what we know in 2020 and a literature review. J Orthop Surg (Hong Kong). 2021;29(1_suppl):23094990211006934.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 6

    Skeppholm M, Lindgren L, Henriques T, Vavruch L, Löfgren H, Olerud C. The Discover artificial disc replacement versus fusion in cervical radiculopathy—a randomized controlled outcome trial with 2-year follow-up. Spine J. 2015;15(6):12841294.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Coric D, Nunley PD, Guyer RD, et al. Prospective, randomized, multicenter study of cervical arthroplasty: 269 patients from the Kineflex|C artificial disc investigational device exemption study with a minimum 2-year follow-up: clinical article. J Neurosurg Spine. 2011;15(4):348358.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Phillips FM, Lee JYB, Geisler FH, et al. A prospective, randomized, controlled clinical investigation comparing PCM cervical disc arthroplasty with anterior cervical discectomy and fusion. 2-year results from the US FDA IDE clinical trial. Spine (Phila Pa 1976). 2013;38(15):E907E918.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9

    Murrey D, Janssen M, Delamarter R, et al. Results of the prospective, randomized, controlled multicenter Food and Drug Administration investigational device exemption study of the ProDisc-C total disc replacement versus anterior discectomy and fusion for the treatment of 1-level symptomatic cervical disc disease. Spine J. 2009;9(4):275286.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Heller JG, Sasso RC, Papadopoulos SM, et al. Comparison of BRYAN cervical disc arthroplasty with anterior cervical decompression and fusion: clinical and radiographic results of a randomized, controlled, clinical trial. Spine (Phila Pa 1976). 2009;34(2):101107.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11

    Gornet MF, Burkus JK, Shaffrey ME, Argires PJ, Nian H, Harrell FE Jr. Cervical disc arthroplasty with PRESTIGE LP disc versus anterior cervical discectomy and fusion: a prospective, multicenter investigational device exemption study. J Neurosurg Spine. 2015;23(5):558573.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 12

    Badhiwala JH, Platt A, Witiw CD, Traynelis VC. Cervical disc arthroplasty versus anterior cervical discectomy and fusion: a meta-analysis of rates of adjacent-level surgery to 7-year follow-up. J Spine Surg. 2020;6(1):217232.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Zhu RS, Kan SL, Cao ZG, Jiang ZH, Zhang XL, Hu W. Secondary surgery after cervical disc arthroplasty versus fusion for cervical degenerative disc disease: a meta-analysis with trial sequential analysis. Orthop Surg. 2018;10(3):181191.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 14

    Zhong ZM, Zhu SY, Zhuang JS, Wu Q, Chen JT. Reoperation after cervical disc arthroplasty versus anterior cervical discectomy and fusion: a meta-analysis. Clin Orthop Relat Res. 2016;474(5):13071316.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Park J, Shin JJ, Lim J. Biomechanical analysis of disc pressure and facet contact force after simulated two-level cervical surgeries (fusion and arthroplasty) and hybrid surgery. World Neurosurg. 2014;82(6):13881393.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Laxer EB, Darden BV, Murrey DB, et al. Adjacent segment disc pressures following two-level cervical disc replacement versus simulated anterior cervical fusion. Stud Health Technol Inform. 2006;123:488492.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 17

    Gordon AM, Golub IJ, Ng MK, Lam AW, Houten JK, Saleh A. Primary and revision cervical disc arthroplasty from 2010-2020: patient demographics, utilization trends, and healthcare reimbursements. World Neurosurg. 2022;168:e344e349.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 18

    Chen G, Khan N, Walker R, Quan H. Validating ICD coding algorithms for diabetes mellitus from administrative data. Diabetes Res Clin Pract. 2010;89(2):189195.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 19

    Casp AJ, Montgomery SR Jr, Cancienne JM, Brockmeier SF, Werner BC. Osteoporosis and implant-related complications after anatomic and reverse total shoulder arthroplasty. J Am Acad Orthop Surg. 2020;28(3):121127.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20

    Wiley LK, Shah A, Xu H, Bush WS. ICD-9 tobacco use codes are effective identifiers of smoking status. J Am Med Inform Assoc. 2013;20(4):652658.

  • 21

    Maron SZ, Neifert SN, Ranson WA, et al. Elixhauser comorbidity measure is superior to Charlson Comorbidity Index in-predicting hospital complications following elective posterior cervical decompression and fusion. World Neurosurg. 2020;138:e26e34.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 22

    Guzman JZ, Feldman ZM, McAnany S, Hecht AC, Qureshi SA, Cho SK. Osteoporosis in cervical spine surgery. Spine (Phila Pa 1976). 2016;41(8):662668.

  • 23

    Jain N, Labaran L, Phillips FM, et al. Prevalence of osteoporosis treatment and its effect on post-operative complications, revision surgery and costs after multi-level spinal fusion. Global Spine J. 2022;12(6):11191124.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24

    Seicean A, Seicean S, Alan N, et al. Effect of smoking on the perioperative outcomes of patients who undergo elective spine surgery. Spine (Phila Pa 1976). 2013;38(15):12941302.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 25

    Grønkjær M, Eliasen M, Skov-Ettrup LS, et al. Preoperative smoking status and postoperative complications: a systematic review and meta-analysis. Ann Surg. 2014;259(1):5271.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 26

    Skeppholm M, Henriques T, Tullberg T. Higher reoperation rate following cervical disc replacement in a retrospective, long-term comparative study of 715 patients. Eur Spine J. 2017;26(9):24342440.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 27

    MacDowall A, Skeppholm M, Lindhagen L, et al. Artificial disc replacement versus fusion in patients with cervical degenerative disc disease with radiculopathy: 5-year outcomes from the National Swedish Spine Register. J Neurosurg Spine. 2018;30(2):159167.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 28

    Saifi C, Fein AW, Cazzulino A, et al. Trends in resource utilization and rate of cervical disc arthroplasty and anterior cervical discectomy and fusion throughout the United States from 2006 to 2013. Spine J. 2018;18(6):10221029.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 29

    Kumar C, Dietz N, Sharma M, Wang D, Ugiliweneza B, Boakye M. Long-term comparison of health care utilization and reoperation rates in patients undergoing cervical disc arthroplasty and anterior cervical discectomy and fusion for cervical degenerative disc disease. World Neurosurg. 2020;134:e855e865.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 30

    Kelly MP, Eliasberg CD, Riley MS, Ajiboye RM, SooHoo NF. Reoperation and complications after anterior cervical discectomy and fusion and cervical disc arthroplasty: a study of 52,395 cases. Eur Spine J. 2018;27(6):14321439.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 31

    Nunley P, Frank K, Stone M. Patient selection in cervical disc arthroplasty. Int J Spine Surg. 2020;14(s2):S29S35.

  • 32

    Shah RV, Albert TJ, Bruegel-Sanchez V, Vaccaro AR, Hilibrand AS, Grauer JN. Industry support and correlation to study outcome for papers published in Spine. Spine (Phila Pa 1976). 2005;30(9):10991105.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 33

    Singh K, Phillips FM, Park DK, Pelton MA, An HS, Goldberg EJ. Factors affecting reoperations after anterior cervical discectomy and fusion within and outside of a Federal Drug Administration investigational device exemption cervical disc replacement trial. Spine J. 2012;12(5):372378.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 34

    Cher DJ, Capobianco RA. Spine device clinical trials: design and sponsorship. Spine J. 2015;15(5):11331140.

  • 35

    Sundseth J, Fredriksli OA, Kolstad F, et al. The Norwegian Cervical Arthroplasty Trial (NORCAT): 2-year clinical outcome after single-level cervical arthroplasty versus fusion—a prospective, single-blinded, randomized, controlled multicenter study. Eur Spine J. 2017;26(4):12251235.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 36

    Xie L, Liu M, Ding F, Li P, Ma D. Cervical disc arthroplasty (CDA) versus anterior cervical discectomy and fusion (ACDF) in symptomatic cervical degenerative disc diseases (CDDDs): an updated meta-analysis of prospective randomized controlled trials (RCTs). Springerplus. 2016;5(1):1188.

    • PubMed
    • Search Google Scholar
    • Export Citation

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