Number of Cervical Spine Surgeries Increased in the Last Decade

Peer Review by Ali A. Baaj, MD

Peer Reviewed

Comments by Kern Singh, MD and Majorie Wang, MD, MPH

cervical vertebrae, lateral viewThe number of cervical spine surgeries increased significantly in the last decade, irrespective of the 2008 U.S. Food and Drug Administration warning on use of bone morphogenetic protein (BMP) for these procedures, according to a retrospective database analysis published in Spine.

“This study is another example of the multifaceted nature of spine surgery with constantly evolving trends and patient demographics,” said coauthor Kern Singh, MD, Associate Professor of Orthopedic Surgery, Rush University Medical Center, Chicago. “This study provides an update for spine surgeons, hospitals, and payors to understand recent shifts in the practice of cervical spine surgery. It also demonstrates the magnitude of influence that governmental agencies have with regards to practice trends,” Dr. Singh said.

Dr. Singh emphasized that “despite significant demographic shifts within our patient population, outcomes have either remained stable or improved between 2002 and 2011. This should reinforce our efforts to improve the quality of spine surgery and implement methods to check the rising costs of spinal healthcare.”

“This study improves knowledge about trends in cervical spine surgery and, specifically, changes in practice patterns in response to the FDA public health warning about BMP,” commented Marjorie Wang, MD, MPH, Associate Professor of Neurosurgery at the Medical College of Wisconsin in Milwaukee. “It also provides an overall picture of the use of BMP among anterior and posterior cervical fusions in the US,” Dr. Wang said.

Data Derived From Large, Nationwide Database
The authors used the Nationwide Inpatient Sample database to identify 307,188 cervical spine procedures (ie, anterior cervical fusion, posterior cervical fusion, and posterior cervical decompression) performed from 2002 to 2011.

Overall, the number of procedures increased from 27,445 in 2002 to 36,441 in 2011 (P<0.001), with anterior cervical fusions being the most common type (84%). When the individual procedures were examined, the number of anterior cervical fusion and posterior cervical fusion procedures significantly increased significantly (r=+0.9 for both surgeries; P=0.001 and P<0.001, respectively). In contrast, the number of posterior cervical fusion procedures did not increase significantly; this surgery was linked to greater comorbidity, length of stay, costs, and mortality.

The age and comorbidity burden of the patient population increased significantly during this period (P<0.001 for both variables). In contrast, hospital length of stay and mortality did not significantly change.

Overall, use of BMP increased significantly over the study period (r=+0.7, P=0.02) and peaked in 2007, but its use declined thereafter. In 2008, the FDA issued a warning regarding reports of severe neck and throat swelling associated with BMP use.

Why Are Spinal Surgeries on the Rise?
“I think the overall trends regarding the number of cervical spine procedures is increasing due to a multitude of factors, chief of which is an aging population,” Dr. Singh said. “The FDA Public Health Notifications did influence trends with regards to BMP utilization in anterior cervical spine surgery, as we demonstrated a downtrend in the number anterior cervical fusion cases with BMP. However, I speculate that the overall trends in the number of cervical spine procedures is increasing due to an aging population and growing evidence regarding the cost-effectiveness and efficacy of cervical spine surgery in reducing the burden of degenerative cervical spine disease,” Dr. Singh said.

Interpreting the Findings
Strengths of the study include a large sample size, and that the study provides an opportunity to evaluated costs, Dr. Wang told SpineUniverse. “The authors highlight the limitations of the dataset, including lack of information about disease severity, indications for surgery, and diagnostic imaging. In addition, use of ICD9-CM codes limits our ability to determine the complexity of the surgical procedure, and procedures such as laminoplasty may be classified under posterior cervical decompression. Because of these limitations, we should be cautious about comparing the anterior and posterior surgical approach since there may be significant differences, for example in patient age, indications for surgery, diagnosis of myelopathy, and surgical complexity,” Dr. Wang said.

“In addition, the Nationwide Inpatient Sample only contains information about the hospital stay associated with the surgery, so patients cannot be followed over time and after discharge. Many of the complications associated with BMP use may not have been noted during the initial hospital stay,” Dr. Wang added.

“The authors comment that ‘the reduction of BMP utilization has not discouraged surgeons from performing ACFs’ and the FDA warning had ‘little to no impact in the overall number of cervical fusion surgical procedures that were performed in the last decade.’ This is consistent with the overall trend to increasing numbers of cervical spine surgeries performed in the US that was found in other prior studies (Patil et al, etc),” Dr. Wang said. “In addition, since BMP is an adjunct and not an essential part of these commonly performed surgeries, I would not necessarily have anticipated an overall impact on cervical spine surgery trends from the FDA warning. There was a distinct decrease in use of BMP after the FDA warning, but BMP was still used. It would be interesting to further study those patients who still underwent surgery with BMP (5.8% among anterior cervical fusions and 13.4% among posterior cervical fusions),” Dr. Wang concluded.

Peer Review by Ali A. Baaj, MD
Assistant Professor of Neurological Surgery
Weill Cornell Medical College, Cornell University
New York, NY

Increases in healthcare utilization coupled with a rise in costs have resulted in a seemingly unsustainable health care delivery model in the United States. Focusing on cost-effective treatment modalities that are based on the results of comparative effectiveness research and evidence-based medicine is paramount in all facets of medicine, and spine surgery is no exception.

The following work by Dr. Singh and colleagues from Rush University Orthopedics Department is therefore timely and pertinent. By querying the federal National Inpatient Sample (NIS) database, they have highlighted the following facts:

  1. The number of cervical spine surgeries over a 10-year period has increased
  2. The costs associated with these procedures have increased
  3. The utilization of bone morphogenetic protein (BMP) in cervical spine surgeries declined after 2007

None of these findings is surprising, and the authors provide a balanced discussion of these facts. It should be noted, however, that increase does not always mean overutilization. Advancements in technology and perioperative medical management have enabled us to more confidently choose the more effective, definitive, and predictable surgical option in some cases. When surgery is based on sound indications, it may very well be the more cost-effective option, and thus should arguably be utilized more frequently.

Despite the known shortcomings of population-based databases, like the NIS, they remain instrumental in helping us understand trends on a national level. Studies, like this one, should encourage us to ensure that the rise in utilization is substantiated by sound indications and proven outcomes.

Updated on: 08/25/16
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