CORR Insights®: Does Operative Management of Epidural Abscesses Increase Healthcare Expenditures up to 1 Year After Treatment?

Where Are We Now?

Epidural abscesses are a treatment complication that can result in permanent neurologic deficit, including paralysis. Abscesses may also lead to more complicated, challenging, and potentially life-threatening situations such as septic discitis, osteomyelitis, and septic shock.

Although the ways we manage epidural abscesses have dramatically changed over my practice lifetime, our treatment options are still somewhat in a state of flux. Epidural abscess treatment has evolved from being an absolute indication for surgery during approximately the last 40 years of the 20^th century, to limited numbers of patients being treated nonsurgically in the early 2000s, and ultimately, progressing along the path to our present approach where approximately half of all abscesses are treated without an operation. For example, we now know that patients with epidural abscesses but without a neurologic deficit, systemic sepsis, or intractable pain may be treated successfully without surgery [2].

Traditionally, immune compromise has been recognized as a major risk factor, both for infections in general as well as for epidural abscesses. In our present-day society, however, intravenous (IV) drug use has emerged as another risk factor for developing epidural abscesses [1].

In the current study, Xiong et al. [4] retrospectively reviewed the treatment of 90 patients with epidural abscesses from both a clinical and cost perspective. Surgical intervention was performed in 52% of patients and nonoperative treatment conducted in 48%. The cohorts had similar demographics. Patients having surgery were found to have incurred higher costs but both groups had similar readmission rates and mortality.

An interesting subanalysis was performed between the patients with a history of IV drug use (29% of all patients) versus the non-IV group. In fact, patients who use IV drugs had higher costs on the initial hospitalization, but at a 1-year review, the costs incurred by both cohorts were similar.

The study also confirms the viability of our present treatment direction for epidural abscesses, with essentially an even split between surgical and nonsurgical options in their cohorts without a considerable difference in cost or clinical outcome. In addition, IV drug use is corroborated as a risk factor for the development of epidural abscess.

Where Do We Need To Go?

Further refinement of the indications for the choice of surgical versus nonsurgical care is a high priority. Research questions that could help define the best treatment option include: (1) Are there timeframe, physical exam (neurologic status), laboratory (WBC, erythrocyte sedimentation rate, C-reactive protein), or imaging criteria or trends that constitute more definite indications for initial surgical care (for example, liquid rather than granulation appearance of abscesses on MRI, obstruction of a percentage of the spinal canal, myelomalacia of the cord even without neurologic deficit)? (2) If a patient initially undergoes nonsurgical treatment, are there timeframe, physical exam, laboratory, or imaging criteria or trends that show that a change to surgical intervention would produce the best outcome? (3) Does IV drug use predispose the patient to epidural abscesses in the cervical and thoracic spine (where the cord is more sensitive to pressure) rather than the lumbar spine (in the less sensitive cauda equina)?

Additionally, cost remains a factor in our treatment decisions. Therefore, clinicians need to become familiar with and perform cost-effectiveness analyses on alternative treatment options for epidural abscesses similar to studies like the Spine Patient Outcomes Research Trial (SPORT) [3].

How Do We Get There?

The research questions above are good examples of issues that can be investigated through registries. Epidural abscess is not a commonly occurring pathology. Thus, being able to pool larger numbers of patients’ data from registries may produce answers to many of the lingering treatment questions without the need for more expensive, tedious, and largely impractical randomized clinical trials.

In terms of determining the cost effectiveness of the various treatment options, our traditional research data points and outcomes instruments must be modified. Direct cost expenditures for treatment must be collected as well as indirect costs such as the value associated with time off work.

Finally, outcomes instruments for these studies need to include the measures (EQ-5D, SF-6D, and Health Utility Index) whose tallies can be converted to utility scores. This allows the calculation of Quality Adjusted Life Years (QALYs), which are ultimately used to answer the cost effectiveness equation: Value = Outcomes (determined by improvement in QALYs)/Cost (direct/indirect).