|Year : 2022 | Volume
| Issue : 3 | Page : 331-338
What is a better value for your time? Anterior cervical discectomy and fusion versus cervical disc arthroplasty
Austen David Katz, Junho Song, Daniel Bowles, Terence Ng, Eric Neufeld, Sayyida Hasan, Dean Perfetti, Nipun Sodhi, David Essig, Jeff Silber, Sohrab Virk
Department of Orthopedic Surgery, North Shore University Hospital and Long Island Jewish Medical Center, Zucker School of Medicine, Hofstra University, New York, USA
|Date of Submission||17-May-2022|
|Date of Acceptance||19-Jul-2022|
|Date of Web Publication||14-Sep-2022|
Austen David Katz
Department of Orthopedic Surgery, Long Island Jewish Medical Center, 270-05 76th Avenue, Queens, New York 11040
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Introduction: Compared to anterior cervical discectomy and fusion (ACDF), the motion preservation of cervical disc arthroplasty (CDA) provides an attractive alternative with similar short-term results. However, there is a paucity of the economics of performing CDA over ACDF.
Study Design: This was retrospective study.
Objective: The objective of this study is to evaluate relative-value-units (RVUs), operative time, and RVUs-per-minute between single-level ACDF and CDA. Secondary outcomes included 30-day readmission, reoperation, and morbidity.
Methods: Adults who underwent ACDF or CDA in 2011–2019 National Surgical Quality Improvement Program database datasets. Multivariate quantile regression was utilized.
Results: There were 26,595 patients (2024 CDA). ACDF patients were older, more likely to be female, discharged to inpatient rehabilitation, and have a history of obesity, smoking, diabetes, steroid use, and the American Society of Anesthesiologists-class ≥≥3. ACDF had greater median RVUs-per-case (41.2 vs. 24.1) and RVUs-per-minute (0.36 vs. 0.27), despite greater operative-time (109 min vs. 92 min) (P < 0.001). ACDF predicted a 16.9 unit increase in median RVUs per case (P < 0.001, confidence interval [CI]95: 16.3–17.5), an 8.81 min increase in median operative time per case (P < 0.001, CI95: 5.69–11.9), and 0.119 unit increase in median RVUs-per-minute (P < 0.001, CI95: 0.108–0.130). ACDF was associated with greater unadjusted rates of readmission (3.2% vs. 1.4%) morbidity (2.3% vs. 1.1%) (P < 0.001), but similar rates of reoperation (1.3% vs. 0.8%, P = 0.080). After adjusting for significant patient-related and procedural factors, readmission (odds ratio [OR] = 0.695, P = 0.130, CI95: 0.434–1.113) and morbidity (OR = 1.102, P = 0.688, CI95: 0.685–1.773) was similar between ACDF and CDA.
Conclusions: Median RVUs-per-minute increased by 0.119 points for ACDF over CDA, or $257.7/h for each additional-hour of surgery. Adjusted 30-day outcomes were similar between procedures. Reimbursement for CDA does not appear to be in line with ACDF and may be a barrier to widespread usage.
Keywords: Anterior, arthroplasty, cervical, comparative, fusion, morbidity, national surgical Quality Improvement Program Database, relative-value-units
|How to cite this article:|
Katz AD, Song J, Bowles D, Ng T, Neufeld E, Hasan S, Perfetti D, Sodhi N, Essig D, Silber J, Virk S. What is a better value for your time? Anterior cervical discectomy and fusion versus cervical disc arthroplasty. J Craniovert Jun Spine 2022;13:331-8
|How to cite this URL:|
Katz AD, Song J, Bowles D, Ng T, Neufeld E, Hasan S, Perfetti D, Sodhi N, Essig D, Silber J, Virk S. What is a better value for your time? Anterior cervical discectomy and fusion versus cervical disc arthroplasty. J Craniovert Jun Spine [serial online] 2022 [cited 2023 Mar 23];13:331-8. Available from: https://www.jcvjs.com/text.asp?2022/13/3/331/355995
| Introduction|| |
Cervical disc arthroplasty (CDA) is a relatively novel technique used to manage the cervical degenerative disease. Conventionally, anterior cervical discectomy and fusion (ACDF) has been the treatment of choice for anterior cervical surgery, but CDA has become increasingly utilized. The unique aspect of disc replacement is its motion-preserving ability, contrasting it with fusion. Initial arthroplasty designs utilized a ball-and-socket prosthesis to replicate physiologic motion in all rotational planes, but have evolved to include at least seven Food and Drug Administration-approved devices for single-level arthroplasty. The touted benefit of maintaining motion is that it may reduce the risk of adjacent segment disease, although whether this holds true in practice remains unclear.,,,, In addition, CDA is not without its own set of complications, including instability and heterotopic ossification.
ACDF has persisted as one of the tried-and-true surgical solutions for treating degenerative cervical disease. Although the number of ACDFs performed annually continues to far outpace the number of CDAs, there has been an increasingly greater demand for CDA., Niedzielak et al. performed a trend analysis of CDA in the Medicare database which revealed a high annual growth rate of CDA utilization of 20.54%. A greater expansion of CDA however has been inpart limited by surgical indications. Although there are no strict criteria for the degree of facet degeneration as a contraindication to CDA, it is generally avoided in patients with facet arthritis or a kyphotic deformity >15°. But with indications equal, are there value-related benefits to performing one over the other? As health-care systems shift toward value-based care and alternative payment models, it is crucial to understand the economic implications of treatments in spine surgery.
Although the usage of CDA has been increasing, there is a paucity of literature on the economics of performing CDA over ACDF. This is particularly relevant considering the similar short-term outcomes observed between the two procedures in recent studies.,, Although prior studies have evaluated the cost-effectiveness of CDA, there is no study comparing the reimbursement rate between ACDF and CDA., Therefore, the purpose of this study was to compare relative-value-units (RVUs)-per-minute between single-level ACDF and CDA. We also compared 30-day readmission, reoperation, and morbidity rates.
| Methods|| |
Study design and population
This retrospective cohort study utilizes data obtained from the American College of Surgeons National Surgical Quality Improvement Program database (NSQIP). NSQIP has been shown to have excellent validity, reliability, and a low rate of reporting error., Patients ≥18 years old who underwent ACDF or CDA between 2011 and 2019 were identified and included based on Current Procedural Terminology (CPT) codes 22856 and 22551, respectively. Patients were excluded if they underwent >1 level of surgery; had nonelective/emergency, deformity, tumor, or revision surgery; or had CPT codes for laminectomy/laminotomy, thoracic, lumbar, pelvic, or posterior procedures, or corpectomy. Patients with missing outcome data were also excluded to prevent biases in the results.
Outcomes and variables
Primary outcomes included RVUs per case, RVUs per minute, and operative time. Secondary outcomes included 30-day readmission, reoperation, morbidity, and specific complications. Readmission was defined as any inpatient stay in the same or another hospital related to the surgical procedure. Reoperation was defined as all major surgical procedures requiring return to the operating room for the intervention of any kind. Morbidity was defined as the occurrence of one or more complications reported in the NSQIP dataset, including infectious, cardiopulmonary, renal, neurological, hematologic, and thromboembolic complications.
All statistical analyses were performed using SPSS software (version 28, IBM, Armonk, New York, USA). Demographic, comorbidity, laboratory, and procedural factors were individually analyzed for baseline differences between ACDF and CDA using Student's t-test, Kruskal–Wallis H-test, Chi-squared, or Fisher's exact test as appropriate. The above factors were also individually analyzed for any associations with the primary outcomes using univariate logistic regression. Baseline variables that significantly (P < 0.05) differed between ACDF and CDA were included and controlled for in multivariate analysis. Multivariate analysis of readmission, reoperation, and morbidity was performed using logistic regression. The assumption of normality for RVUs per case, RVUs per minute, and operative time was assessed using the Kolmogorov–Smirnov test and was not met. Therefore, regression coefficients for RVUs-per-case, RVUs-per-minute, and ORT were estimated through quantile (median) regression.
| Results|| |
A total of 26,595 patients (24,571 ACDF; 2,024 CDA) were included in the study. ACDF patients were older (55 years vs. 45 years), more likely to be female (50% vs. 46%), more likely to be discharged to an inpatient rehabilitation facility (3% vs. 0.6%), and had greater rates of medical comorbidities including obesity, smoking history, diabetes, steroid use, and the American Society of Anesthesiologists-class ≥3 [Table 1].
|Table 1: Baseline differences in patient demographic, comorbidity, laboratory, and procedural factors by procedure|
Click here to view
In univariate analysis, ACDF had greater median RVUs per case (41.2 vs. 24.1) and RVUs-per-minute of OR time (0.36 vs. 0.27), despite having greater odds ratio (OR) time per case (109 min vs. 92 min) (P < 0.001). ACDF was associated with longer mean hospital stay (1.5 days vs. 1.0 days) and fewer outpatient procedures (34% vs. 52%) (P < 0.001). ACDF was also associated with greater unadjusted rates of readmission (3.2% vs. 1.4%) and morbidity (2.3% vs. 1.1%) (P < 0.001), but similar rates of reoperation (1.3% vs. 0.8%, P = 0.080) [Table 2].
|Table 2: Univariate and multivariate analyses of primary outcomes and specific complications by procedure|
Click here to view
After adjusting for significant patient-related and procedural factors in multivariate logistic regression analysis, readmission (OR = 0.695, P = 0.130, confidence interval [CI]95: 0.434–1.113) and morbidity (OR = 1.102, P = 0.688, CI95: 0.685–1.773) no longer statistically differed between ACDF and CDA [Table 3],[Table 4],[Table 5]. Variables that independently predicted readmission, reoperation, and morbidity are provided in [Table 3],[Table 4],[Table 5], respectively.
|Table 3: Univariate and multivariate analysis of predictors of readmission|
Click here to view
|Table 4: Univariate and multivariate analysis of predictors of reoperation|
Click here to view
|Table 5: Univariate and multivariate analysis of predictors of morbidity|
Click here to view
Multivariate quantile regression analysis revealed that ACDF predicted a 16.9 unit increase in median RVUs per case (P < 0.001, CI95: 16.3–17.5), an 8.81 min increase in median operative time per case (P < 0.001, CI95: 5.69–11.9), and a 0.119 unit increase in median RVUs per minute (P < 0.001, CI95: 0.108–0.130).
| Discussion|| |
As the United States healthcare shifts toward value-based systems, RVUs are increasingly utilized to determine physician reimbursements nationally. This reimbursement system has been designed to better correlate compensation with the amount of physician work involved in providing the service. In general, higher RVUs are assigned to more complex procedures because the RVU payment model considers the physician's work, practice expenses, and professional liability insurance. Despite these considerations, several studies have found inappropriate RVU assignments to certain procedures, characterized by failures to accurately capture the degree of complexity involved.,,, Therefore, a thorough assessment of RVUs for cervical spine surgical procedures is necessary.
The aim of the current study was to compare the mean RVUs, operative time, and RVUs per minute between single-level ACDF and CDA. Our findings showed that single-level ACDF was associated with greater operative time than CDA. However, ACDF also had greater median RVUs per case, yielding greater RVUs per minute of operative time. Our analysis also revealed no statistical difference in readmission, reoperation, and morbidity between the two procedures after adjusting for patient-related factors.
Some cost analyses comparing ACDF and CDA have been performed. McAnany et al. evaluated the 5-year cost-effectiveness of ACDF and CDA using a Markov analysis, which revealed that although both procedures are cost-effective strategies at 5 years, CDA was the dominant treatment strategy at higher utility values. A database analysis by Radcliff et al. also favored CDA due to significant monthly cost reductions compared to ACDF. However, no study has previously compared the physician reimbursement rates of the two procedures. Our model showed that after adjusting for patient-related and procedural factors, the median RVU/minute increased by 0.119 points for ACDF compared to CDA. This equates to $257.7/h for each additional hour of operative time using the 2020 Medicare conversion factor ($36.09)., While this value is general and does not apply to all surgeon reimbursement structures, this is a significant finding given that physician reimbursement for a procedure may affect the rate at which CDA is performed and therefore its utilization, advancement, and technological perfection.
The present study also compared 30-day outcomes between ACDF and CDA. After adjusting for baseline patient and procedural characteristics in multivariate analysis, there was no statistically significant difference in readmission, reoperation, and morbidity rates between the two procedures. Similar findings regarding clinical outcomes of ACDF and CDA have been previously reported. Kumar et al. examined ACDF and CDA outcomes with a 5-year follow-up period and found no difference in reoperation, readmission, or health-care utilization between the procedures during the study.
Interestingly, current literature comparing ACDF to CDA is conflicted, and several studies have reported contrasting results demonstrating significant differences in outcomes, often favoring CDA over ACDF. Xie et al. performed a meta-analysis on CDA and ACDF including 37 articles with 20 randomized-controlled trials. The authors reported that ACDF was associated with higher complication and reoperation rates compared to CDA. Shillingford et al. performed a propensity score-matched comparison of CDA and ACDF and found that ACDF was associated with significantly higher readmission rate and length of stay. Bhashyam et al. also reported a higher readmission rate for single-level CDA compared to single-level ACDF but this difference was limited to the 41–60-year age group. These conflicting findings may be related to learning curves and surgeon experience, considering the significantly lower number of CDAs performed. Given the differing findings in the literature, further investigations comparing the outcomes of ACDF and CDA are warranted.
Several limitations must be considered when interpreting the current study. The NSQIP database is largely comprised of academic medical centers, which may introduce generalizability bias. There was also a disproportionately small number of patients who underwent CDA compared to ACDF. Nevertheless, the NSQIP database allowed for a large sample size and an adequately powered study with a large breadth of surgeons performing an overall less common procedure, CDA. Operative time may not be a perfect indicator of physician work and likely varied significantly depending on several nonprocedural factors, such as the presence of trainees and the frequency of ACDF and CDA procedures performed by the surgeon. This study is also limited by the differences in indications inherent to ACDF and CDA. While the NSQIP database does not provide a way to control for radiographic-based indications, our rigorous CPT-based exclusion criteria and multivariate analyses controlling for procedural and patient-related factors provide reassurance that both groups are comparable.
| Conclusions|| |
The current study determined that ACDF offers a significantly greater value per minute of operative time than CDA despite requiring longer operative times on a national scale. Specifically, ACDF predicted a median RVU per minute increased by 0.119 points compared to CDA, equating to $257.7/h for each additional hour of operative time. In addition, while CDA appears to have a more favorable 30-day outcome safety profile, adjusting for patient-related and procedural factors revealed statistically similar outcomes in readmission, reoperation, and morbidity. The significance of this study is underscored by advancements in modern disc arthroplasty technology as well as by changes in the health system, ultimately necessitating greater efficiency. The results of this study can help guide surgical solution to treating cervical disease that may be amenable to either fusion or arthroplasty by a surgeon with similar skill and comfort level in either procedure.
Financial support and sponsorship
Dr. Silber receives teaching fees for Stryker.
Dr. Essig receives consulting fees for Stryker and DePuy.
For all remaining authors, none were declared. No funding was received in connection with this study.
Conflicts of interest
There are no conflicts of interest.
| References|| |
Steinberger J, Qureshi S. Cervical disc replacement. Neurosurg Clin N Am 2020;31:73-9.
Puttlitz CM, Rousseau MA, Xu Z, Hu S, Tay BK, Lotz JC. Intervertebral disc replacement maintains cervical spine kinetics. Spine (Phila Pa 1976) 2004;29:2809-14.
Wang F, Shen Y, Du W, Tong T, Miao DC, Hua ZJ, et al.
Long-term outcomes of Bryan artificial cervical disc replacement for degenerative cervical spondylosis. Zhonghua Yi Xue Za Zhi 2020;100:3602-8.
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;5:1188.
Zhong ZM, Li M, Han ZM, Zeng JH, Zhu SY, Wu Q, et al.
Does cervical disc arthroplasty have lower incidence of dysphagia than anterior cervical discectomy and fusion? A meta-analysis. Clin Neurol Neurosurg 2016;146:45-51.
DiAngelo DJ, Roberston JT, Metcalf NH, McVay BJ, Davis RC. Biomechanical testing of an artificial cervical joint and an anterior cervical plate. J Spinal Disord Tech 2003;16:314-23.
Zhu Y, Zhang B, Liu H, Wu Y, Zhu Q. Cervical disc arthroplasty versus anterior cervical discectomy and fusion for incidence of symptomatic adjacent segment disease: A meta-analysis of prospective randomized controlled trials. Spine (Phila Pa 1976) 2016;41:1493-502.
Zechmeister I, Winkler R, Mad P. Artificial total disc replacement versus fusion for the cervical spine: A systematic review. Eur Spine J 2011;20:177-84.
Saifi C, Fein AW, Cazzulino A, Lehman RA, Phillips FM, An HS, 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;18:1022-9.
Lu Y, McAnany SJ, Hecht AC, Cho SK, Qureshi SA. Utilization trends of cervical artificial disc replacement after FDA approval compared with anterior cervical fusion: Adoption of new technology. Spine (Phila Pa 1976) 2014;39:249-55.
Niedzielak TR, Ameri BJ, Emerson B, Vakharia RM, Roche MW, Malloy JP 4th
. Trends in cervical disc arthroplasty and revisions in the Medicare database. J Spine Surg 2018;4:522-8.
Lu VM, Mobbs RJ, Phan K. Clinical outcomes of treating cervical adjacent segment disease by anterior cervical discectomy and fusion versus total disc replacement: A systematic review and meta-analysis. Global Spine J 2019;9:559-67.
MacDowall A, Canto Moreira N, Marques C, Skeppholm M, Lindhagen L, Robinson Y, et al.
Artificial disc replacement versus fusion in patients with cervical degenerative disc disease and radiculopathy: A randomized controlled trial with 5-year outcomes. J Neurosurg Spine 2019;30:323-31.
Findlay C, Ayis S, Demetriades AK. Total disc replacement versus anterior cervical discectomy and fusion: A systematic review with meta-analysis of data from a total of 3160 patients across 14 randomized controlled trials with both short- and medium- to long-term outcomes. Bone Joint J 2018;100-B: 991-1001.
Kim JS, Dowdell J, Cheung ZB, Arvind V, Sun L, Jandhyala C, et al.
The seven-year cost-effectiveness of anterior cervical discectomy and fusion versus cervical disc arthroplasty: A Markov analysis. Spine (Phila Pa 1976) 2018;43:1543-51.
Ament JD, Yang Z, Nunley P, Stone MB, Kim KD. Cost-effectiveness of cervical total disc replacement vs. fusion for the treatment of 2-level symptomatic degenerative disc disease. JAMA Surg 2014;149:1231-9.
Shiloach M, Frencher SK Jr., Steeger JE, Rowell KS, Bartzokis K, Tomeh MG, et al.
Toward robust information: Data quality and inter-rater reliability in the American College of Surgeons National Surgical Quality Improvement Program. J Am Coll Surg 2010;210:6-16.
Sellers MM, Merkow RP, Halverson A, Hinami K, Kelz RR, Bentrem DJ, et al.
Validation of new readmission data in the American College of Surgeons National Surgical Quality Improvement Program. J Am Coll Surg 2013;216:420-7.
Nurok M, Gewertz B. Relative value units and the measurement of physician performance. JAMA 2019;322:1139-40.
Ramirez JL, Gasper WJ, Seib CD, Finlayson E, Conte MS, Sosa JA, et al.
Patient complexity by surgical specialty does not correlate with work relative value units. Surgery 2020;168:371-8.
Gan ZS, Wood CM, Hayon S, Deal A, Smith AB, Tan HJ, et al.
Correlation of relative value units with surgical complexity and physician workload in urology. Urology 2020;139:71-7.
Jiang DD, Chakiryan NH, Gillis KA, Acevedo AM, Chen Y, Austin JC, et al.
Relative value units do not adequately account for operative time in pediatric urology. J Pediatr Surg 2021;56:883-7.
Shah DR, Bold RJ, Yang AD, Khatri VP, Martinez SR, Canter RJ. Relative value units poorly correlate with measures of surgical effort and complexity. J Surg Res 2014;190:465-70.
Peterson J, Sodhi N, Khlopas A, Piuzzi NS, Newman JM, Sultan AA, et al.
A comparison of relative value units in primary versus revision total knee arthroplasty. J Arthroplasty 2018;33:S39-42.
McAnany SJ, Overley S, Baird EO, Cho SK, Hecht AC, Zigler JE, et al.
The 5-year cost-effectiveness of anterior cervical discectomy and fusion and cervical disc replacement: A Markov analysis. Spine (Phila Pa 1976) 2014;39:1924-33.
Radcliff K, Zigler J, Zigler J. Costs of cervical disc replacement versus anterior cervical discectomy and fusion for treatment of single-level cervical disc disease: An analysis of the Blue Health Intelligence database for acute and long-term costs and complications. Spine (Phila Pa 1976) 2015;40:521-9.
Simcox T, Becker J, Kreinces J, Islam S, Grossman M, Gould J. Are orthopaedic trauma surgeons adequately compensated for longer procedures? An analysis of relative value units and operative times from the American College of Surgeons National Surgical Quality Improvement Program Database. J Orthop Trauma 2021;35:e458-62.
Malik AT, Quatman CE, Phieffer LS, Khan SN, Ly TV. Are orthopaedic trauma surgeons being adequately compensated for treating nonunions of the femoral shaft?: An analysis of relative value units. J Am Acad Orthop Surg Glob Res Rev 2020;4:e20.00163.
Doan MK, Chung AS, Makovicka JL, Hassebrock JD, Polveroni TM, Patel KA. Comparison of two-level cervical disc replacement versus two-level anterior cervical discectomy and fusion in the outpatient setting. Spine (Phila Pa 1976) 2021;46:658-64.
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:e855-65.
Shillingford J, Laratta J, Hardy N, Saifi C, Lombardi J, Pugely AJ, et al.
National outcomes following single-level cervical disc arthroplasty versus anterior cervical discectomy and fusion. J Spine Surg 2017;3:641-9.
Bhashyam N, De la Garza Ramos R, Nakhla J, Nasser R, Jada A, Purvis TE, et al.
Thirty-day readmission and reoperation rates after single-level anterior cervical discectomy and fusion versus those after cervical disc replacement. Neurosurg Focus 2017;42:E6.
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]