Cervical Fusion: DRG Charge Trends, Length of Stay, and Comorbidities
You are traveling to another dimension—a dimension not only of sight and sound but of spine. There’s a signpost up ahead. Your next stop—The Cervical Zone. Today we will travel to the cervical zone, to explore a world of codes, fusion, charges, and PearlDiver data.
The cervical spine is made up of seven vertebrae (C1 – C7). C1 is called the atlas, and C2 is called the axis. The cervical spine protects the cervical spinal cord. Nerves in this area of the spine are critical to the functioning of the upper body. For example, the nerves located at C4 control the upper body muscles, those at C7 control the triceps, and those at C8 control the hands. Injury to the cervical spine can easily become life threatening.
Cervical Disorders and Common Outpatient Treatments
In the PearlDiver database, diagnoses of conditions in the cervical region make up six of the 20 most common diagnoses, and include spondylosis, disc herniation, vertebral dislocations, disc degeneration, and cervical stenosis. Next to physical therapy and exercise regimes, epidural injections are the most common conservative treatment in the PearlDiver database for cervical disorders. The benefits of injections are twofold. First, they help the physician more accurately identify the exact area of the spine that is causing the pain. Second, they often reduce the pain, increasing their therapeutic value . Injections are often performed several times prior to surgery.
Consider patient data Table 1 below, produced from the PearlDiver Patient Cost and Utilization Database. The injection and accompanying fluoroscopic guidance records are included. The patient received the first injection on 4/15/2004, a second on 5/12/2004, and a third more than seven months later in December. At this point, eight months after the first injection, no inpatient surgery had yet been performed.
Table 1—Patient Records: Steroidal Injection
Surgery could be the next step in treatment, if pain persists after repeated steroidal injections. According to the PearlDiver data, over 90% of cervical fusions are performed anteriorly. This is in part due to safety issues, because the posterior approach requires that the nerves be retracted in the spinal cord to get to the disc. A discectomy is commonly performed with the fusion. Consider the patients diagnosed with cervical spondylosis below in Table 2. The ICD-9 procedure codes and definitions are highlighted in yellow in this table. Although new technology increasingly enables cervical fusion to be performed on an outpatient basis, we are going to be focusing on inpatient data.
Table 2—Patient Records: Anterior Cervical Fusion
Utilizing ICD-9 and DRG Codes
Inpatient cervical fusion procedures are identified by ICD-9 procedural and diagnosis related group (DRG) codes in the PearlDiver database. The associated DRG codes are the basis for this analysis, because they help us zero in on the type of patient that is treated in the hospital and the estimated resource usage of treatment. DRG coding is essential in order for hospitals to receive proper reimbursement. The ICD-9 code for anterior cervical fusion is 81.02; the DRG codes are 519 (cervical fusion with complications and comorbidities) and 520 (cervical fusion without complications and comorbidities). Our analysis will focus on age-specific data (i.e., for patients ages 35 – 64), based on the DRG code breakdown. In the PearlDiver database, over 80% of anterior cervical fusions are performed within that age group.
As healthcare inflation continues, care providers continue to make efforts toward decreasing the average length of stayassociated with surgery. Anterior cervical fusion surgery is no exception. An analysis of the PearlDiver data has revealed several interesting data points on the subject. Table 3 below shows the average length of stay for anterior cervical fusions with and without complications and comorbidities. While the statistical majority of cervical fusions in the database were performed in patients between the ages of 35 and 64, the average length of stay for patients less than 35 years of age is
above the average for the category. Lengths of stay for patients admitted with complications are also longer. In the PearlDiver database, about 15% of cervical fusion patients are admitted with complications.
Table 3—Average Length of Stay (Days)
Average Charges and Age Relationships
The Cervical Zone is also interested in correlations and age groups. Within the data, an analysis was done by year and by gender over the two DRG codes associated with cervical fusion. Average charges for patients 35 – 64 years of age were compiled. The purpose of the study was to examine relationships between average charges and age within the same DRG classification.
The first step was to examine average charges by age group, sorted by patients admitted with and without complications and comorbidities. The data can be seen in Table 4. Notice that in both males and females, patients with complications and comorbidities have the highest charges, which one would expect. However, the difference is more pronounced in males. In 2004, the average charge for anterior cervical spinal fusions without complications was 78.7% of its counterpart with complications and comorbidities. In 2005, the ratio rose slightly to 80.2%. In other words, there was roughly a 20% premium charged to male patients admitted with complications and comorbidities. In females, the differences in charges are less, as can be seen below in Table 5. Indeed, it would be interesting to see if these premiums were commensurate with actual resources used at the hospital.
Table 4—DRG Charges Comparison: Anterior Cervical Fusion
Chart 1—Average Charges: Males
Table 5—DRG Charges Comparison: Anterior Cervical Fusion
It is time to move on to yet another dimension. We have seen the average differences in charges between genders based on their being admitted with or without complications and comorbidities. However, in the Cervical Zone there is always another question! Could there be a demonstrable relationship between age group and average charge?
One approach is to take a base age group and compare subsequent charges in older age groups against it on a percentage and dollar basis. In Table 6 below, average charges have been tabulated by year and by gender and DRG code. The “base” is the charge in the lower age group (35 – 39). This is the age group against which the others are compared. As can be seen in the table, charges increase by 10 or more percentage points on average as patients grow older. The average change in dollars was calculated in comparison to the 35 – 39 age group as well. Aging costs in the Cervical Zone!