The Cervical Fusion Market and Complication Rates

“If you want something done, give it to the busy man.” Spine surgeons are busy, and perform over 230,000 cervical fusions each year. Sounds like a lot of pains in the neck to me! Today we dive into all things “cervical fusion,” and it’s a busy schedule.

The procedure volumes forecast by age group is first. What goes wrong during this procedure? Using the PearlDiver Patient Records database, we present a comprehensive complication rates study of over 23,000 patients who underwent an inpatient anterior cervical fusion.Instrumentation and graft trends in the procedure?—You bet!   

Cervical Fusion Procedure Volumes Forecast

Let’s begin with the numbers. In 2006, there were over 230,000 cervical fusions, with the anterior approach being employed in over 90% of these. Table 1 displays our annual forecast by age group. The majority of cervical fusions are performed on patients aged 45 to 64. However, we caution against ignoring the demographic shift toward the elderly spine patient, as we believe patients 65 and over will present a sizable market as well. We conservatively estimate growth rates in cervical fusion to be between 2% and 3% annually through 2010.

Currently, there is much discussion regarding the impact cervical total disc replacement (TDR) will have on fusion. Through 2010, our forecast assumes little cannibalization by cervical discs from fusion. However, the outlook for cervical TDRs seems bright. In a prior report we forecast that annual revenues from cervical TDRs could exceed $1 billion by 2015, dependent on reimbursement and successful outcomes. Should cervical TDRs be adopted as the standard of care, then, moving into the next decade, cervical fusion procedures volumes could decline.  

Table 1: Anterior Cervical Fusion Procedure Volumes

Due to good outcomes data and high fusion rates, Anterior Cervical Discectomy and Fusion (ACDF) has become the gold standard for treating chronic neck pain and radiculopathy. Based on the PearlDiver database, the most common primary indications for anterior cervical fusion are as follows:

Cervical disc herniation                           48.6%
Cervical spondylosis w/ myelopathy         16.9%
Cervical intervertebral disc disorder        12.0%
Cervical spondylosis w/o myelopathy       10.0%
All others                                                  12.5%

PearlDiver Complications Analysis

The literature suggests that complication rates are relatively low in anterior cervical arthrodesis. We developed an analysis that focused on complications associated with inpatient anterior cervical fusion when performed as a primary procedure. The results of our study are displayed in Table 2.

Study Design

Using the PearlDiver Patient Records Database, we queried 23,485 patients who underwent anterior cervical fusion as defined by ICD-9 procedure code 81.02. All procedures were performed on an inpatient basis and were coded as the primary procedure. There were 10,912 males (46.5%) and 12,573 females (53.5%) included in our study. The PearlDiver database is based on private payer data, and it should be noted that patients in the study were under 65 years of age. The patients underwent anterior cervical fusion between January 2004 and June 2007.

Complications in the study were defined by ICD-9 diagnosis groupings. The far left column in Table 2 defines the type of complication and the applicable codes used in the category. Complications are presented overall and by gender. We found an overall complication rate of 5.91%. The overall complication rate for male patients was 6.11% while females registered 5.74%. Dysphasia, hematoma, and respiratory complications were most common.

Respiratory complications were also common, but coding anomalies must be taken into account when studying the results. ICD-9 code 997.3 is coded for respiratory complications and appears in the ICD-9 “997” coding set, which is specifically for complications. We also include the code for pulmonary embolism, which is ICD-9 diagnosis code 415.1. Pulmonary embolism occurs when an artery in the lung becomes blocked. The third code set used to derive respiratory complications were ICD-9 codes 518.0 to 518.89, which represent various respiratory conditions. Respiratory complication rates presented in Table 2 include patients coded with any of the codes above. Due to the fact that codes 518.0-518.89 are not always coded as complications, we also present the overall complication rate excluding these codes at the bottom of the table.

A commonly studied complication that occurs during cervical fusion is post-operative dysphasia, which is characterized by difficulty eating due to disruption in the swallowing process. We found that 1.37% of patients were coded as having dysphasia as defined by ICD-9 diagnosis code 787.2.

Table 2: Complication Rates for Anterior Cervical Fusion and Related ICD-9 Coding

PearlDiver Study of Graft Usage by Code in Anterior Cervical Fusion

Due to complications and graft-site morbidity, alternatives to autograft are increasingly being employed. Overall, we found that more than 75% of patients coded as having an anterior cervical interbody fusion (CPT-22554) had a graft coded on the same day. The breakdown of the usage of these codes is seen in Table 3. It can also be seen that that allograft is employed over 65% of the time, reflecting less usage of autograft.

Table 3: Graft Usage in Anterior Cervical Fusion (CPT-22554)

PearlDiver Study of Instrumentation Usage by Code in Anterior Cervical Fusion

Are you ready for more numbers? In order to analyze the prevalence of instrumentation usage and other procedures that accompany anterior cervical fusion, we analyzed how often the appropriate codes were billed with the procedure using CPT codes. The results are displayed in Table 4.

CPT code 63075 is often coded by surgeons seeking reimbursement for the discectomy and decompression procedure performed with the cervical fusion. We found this code was used more than 85% of the time on the day of the surgery.

CPT code 22585 is coded on the day of the surgery for each additional level fused. By analyzing how often this code appears with the primary fusion code, we can ascertain how often a multilevel anterior cervical fusion was performed. We found that the multilevel code appeared in 47.6% of the surgeries.

According to Orthopedic Network News (Volume 18, Number 4, October 2007), the usage of bone as an interbody device in cervical fusion has declined from 98% in 2001 to 69% in 2007. Based on PearlDiver data, CPT code 22582, or implantation of an interbody device such as a synthetic cage or PEEK spacer, was coded on the day of the procedure 32.5% of the time.

Regarding instrumentation usage, anterior instrumentation (2-3 level) was coded 82.6% of the time on the day. Given continued improvements in plating such as low-profile and dynamic plates, this trend should continue.

Table 4: Same Day Procedures Coded With Anterior Cervical Fusion (CPT-22554)

INFUSE® and Anterior Cervical Fusion (NASS 2008 Paper)

In October, we attended NASS 2008 (the North American Spine Society’s annualconference) in Toronto, Canada. Recently, there has been controversy over the off-label use of INFUSE® in the cervical spine and complications have been reported in these patients. INFUSE is approved for use in anterior lumbar fusion and is to be used with the appropriate threaded fusion device. We highlight a paper presented at NASS 2008 regarding the issue. The study was retrospective and was comprised of 58 patients.

Complications of BMP Use in Cervical Spine Surgery
Paper No. 47

Dr. Todd S. Jarosz, Dr. Samuel Chewning,  Jane Keiger, PhD, Piedmont Spine Associates

According to the abstract, the purpose of the study was to “report the complications associated with the application of rh-BMP2 to cervical fusion procedures at a single institution over a two year period.”

Regarding the results, the authors noted that “considerably increased complications (20) were documented in the patients in whom the rh-BMP2 was utilized. Especially, in those patients where it was placed in an uncontained fashion anteriorly. There was a trend toward increased complications with utilization of higher rh-BMP2 doses.”

In conclusion the authors stated that “Gold standard bone grafting techniques seem to be safely utilized in fusion procedures in the spine. The cervical spine has proven much less forgiving with the institution of rhBMP-2 use. Complications induced by the presumed “enhanced inflammatory response” caused by rh-BMP2 were clearly evident in our review.”

Spine Surgeons Will Continue To Be Busy

The gold standard in cervical fusion has been in instrumented ACDF. Literature suggests the surgery is associated with relatively low complication rates, although dysphasia continues to be a noted problem. The usage of instrumentation in the form of cervical plates continues. The implantation of non-bone intervertebral spacers is on the rise, as autograft usage declines. Also, controversial off-label use of rh-BMP2 has caused increased scrutiny regarding complications in growth factors used in ACDF. In the meantime, bullish sentiment regarding cervical disc arthroplasty is the consensus. This could impact cervical fusion volumes moving forward. However, this depends on the devices receiving coverage in an increasingly challenging reimbursement environment.

Bottom line: Spine surgeons will continue to be busy as the industry evolves at a “breakneck” pace.