A new study published in the leading subspecialty journal for the treatment of spinal disorders finds that pain medications are involved in more than 20 percent of injured worker deaths that occur in the years following spinal fusion surgery for low back pain, underscoring growing concerns about long-term risks associated with spinal fusion, especially deaths related to opioid painkillers.

The study, led by Dr. S.M. Juratli of Wayne State University School of Medicine in Detroit, was published in the April 1 issue of Spine. The researchers analyzed data on 2,378 injured workers who underwent spinal fusion surgeries in Washington state between January 1994 and December 2001, compiling data on the frequency, cause and timing of post-surgery deaths using the state’s workers’ compensation claims database and vital statistics records. After adjusting the data to control for age and gender, the results showed that the initial risk of death following a spinal fusion was low – 0.29 percent in the first three months after surgery, and in those cases was highest for patients who had undergone a second spinal fusion. The study, however, also found that 1.9 percent of all workers who had had a spinal fusion died within three years of the surgery, and by 2004, 103 of the 2,378 workers in the study sample (4.33 percent) had died.

If grouped together, diseases of all kinds -- including cancer and heart disease -- accounted for the most deaths, but 22 of the 103 deaths noted by the researchers involved pain medications, making this the single most common cause of death. A closer look at the data showed that among the 22 injured workers whose deaths were caused by painkillers, 19 were due to accidental overdose, while three were suicides. Thus, the study notes, nearly one percent of all workers who underwent spinal fusions died from analgesic poisoning. Furthermore, because the rate of pain medication-related deaths was highest among younger spinal fusion patients (while older patients who passed away were more likely to have died from other causes), the researchers noted that deaths linked to pain medications accounted for nearly one-third (31.4 percent) of the total potential life-years lost.

Several factors were associated with a higher risk of death from painkillers. For example, the rate was higher for workers who received instrumentation or intervertebral cage devices than for patients who received bone-only fusions, and was highest among workers whose back pain was primarily due to degenerative disc disease -- nearly three times higher than for those with other diagnoses. Among the degenerative disc disease patients, the highest death rate was noted among men in the 45 to 54 age bracket, whose risk of death from pain medications was more than seven times higher than that of workers in other age groups.

In recent years, declining claim volume and medical reforms (utilization review, the medical treatment utilization schedule, medical provider networks, inpatient hospital fee schedule revisions, second opinions for spinal surgeries, etc.) have led to a reduction in the total number of spinal fusions in California workers’ compensation. However, the latest inpatient hospital discharge data from the state’s Office of Statewide Health Planning and Development (OSHPD) shows more than 29,000 of these procedures were performed on injured workers from 2002 to 2006, with nearly 4,800 performed in 2006 alone. This is a concern because spinal fusions carry a higher risk of complications than other, less invasive procedures, and opioid medications, which are highly addictive, are often prescribed in the aftermath of these surgeries.

The new research is one of the few studies that has measured long-term mortality results for injured workers who undergo spinal fusions, especially deaths related to opioid medications. These drugs are increasingly used to treat chronic pain, not only in spinal fusions cases, but in other work injury cases as well. A CWCI study last June (http://www.cwci.org/press_release.html?id=76) based on more than 166,000 accident year 2002 – 2005 claims found opioids were prescribed in one out of four California workers’ compensation back injury cases without spinal cord involvement – typically sprains and strains. Furthermore, preliminary results from an upcoming CWCI report, previewed at the Institute’s annual meeting last month, showed that from calendar years 2005 through 2008, Class-II opioid prescriptions increased from 0.9 percent to 5.9 percent of all California workers’ compensation outpatient prescriptions and from 2 percent to 18 percent of all pharmaceutical payments, with increased use of these drugs noted in almost every injury category.

The Division of Workers’ Compensation is currently reviewing comments on proposed regulatory changes to the workers’ compensation medical treatment utilization schedule which would add a section on the management of chronic pain, including guidelines on the use of opioids. CWCI and others have voiced concerns that the proposed regulations set a vague definition of chronic pain (“any pain that persists beyond the anticipated time of healing”), and that the proposed guidelines lack clear recommendations and limitations on the use of opioids and are based on studies and other materials that fail to meet the required strength of evidence and rating methodology. The proposed guidelines conflict with existing guidelines and would supersede them, so if adopted, would permit a lower threshold for the use of many opioids, increasing the number of instances in which these drugs could be prescribed for injured workers in California .

The proposed regulations and CWCI’s comments are posted in the Regulation section at www.cwci.org. An abstract on the study “Mortality After Lumbar Fusion Surgery” is posted at http://journals.lww.com/spinejournal/Abstract/2009/04010/Mortality_After_Lumbar_Fusion_Surgery.18.aspx along with information on purchasing the article from the April 1, 2009 issue of Spine.