"Some patients and their physicians look to ESIs to avoid or delay invasive spine surgery," said Jayme Koltsov, Ph.D., one of the study's authors. "A better understanding of the typical time fram within which patients are likely to have surgery after ESI and who is most likely to have surgery will better inform the shared surgical decision-making process between surgeons and patients."
The study, "Lumbar Epidural Steroid Injections: Incidence and Determinants of Subsequent Surgery," is a retrospective review of the nationally-representative administrative claims data from 2007-2014.
Interestingly, the researchers found that patients with the diagnosis of disc herniation went on to surgery at a 2.4 higher rate than those with spinal stenosis. The team identified other factors associated with increased rates of lumbar surgery after ESI, including:
- concomitant spine diagnoses (other than herniation and/or stenosis)
- younger age
- male sex
- ESI without fluoroscopic guidance
- residence in the Northeastern or rural United States
- previous treatment for tobacco use
Conversely, female gender and certain medical comorbidities—including cardiopulmonary and neurologic comorbidities, obesity, chronic pain, anxiety, and previous treatment for drug use—were associated with lower rates of subsequent surgery.
Survival analyses were performed using the Marketscan databases 2007-2014 (representing 15 million unique patients from over 100 payers). Inclusion criteria were a diagnosis of stenosis or herniation and active enrollment for one year prior to the ESI to screen for exclusions. Patients were followed longitudinally until they either progressed to surgery or had a lapse in health plan enrollment, at which time they were censored. Differences in survival with patient demographics and treatment details were assessed with multivariable Cox proportional hazard models (SAS 9.4, two-sided α = 0.001).
A total of 203,001 patients meeting the inclusion and exclusion criteria were identified (age 53±15 years, 48 percent female). Within six months, 17.6 (99 percent CI: 17.3, 17.9) percent of ESI patients underwent lumbar surgery. By one year, this increased to 23.7 (99 percent CI: 23.3, 24) percent and by five years, this reached 36.2 (99 percent CI: 35.7, 36.7) percent. Patients with disc herniation progressed to surgery at 2.38 (99 percent CI: 2.27, 2.49) times the rate of those with steroids (p<0.001). A concomitant diagnosis of neuritis, radiculitis, or radiculopathy was associated with an over five-fold increase in the rate of surgery [hazard ratio: 5.34 [(99 percent CI: 5.14, 5.53), p<0.001]. The increase in surgery rates with other concomitant spine diagnoses ranged from a 22 percent increase with spondylosis to an 87 percent increase with instability (p<0.001 for each). Conversely, female sex was associated with a 15 percent lower rate of surgery [hazard ratio: 0.85 (99 percent CI: 0.83, 0.88), p<0.001] and fluoroscopic guidance was associated with a 12 percent lower rate of surgery [hazard ratio: 0.88 (99 percent CI: 0.85, 0.92), p<0.001]. A number of medical comorbidities were associated with decreased surgery rates. This was most pronounced for patients with CHF [hazard ratio: 0.84 (99 percent CI: 0.76, 0.92)], followed by previous treatment for drug use, and then chronic pain, obesity, anxiety, other cardiac complications, hypercholesterolemia, and chronic obstructive pulmonary disease (p<0.001 for each).
Additional study, including symptom severity and the extent of neural compression, will shed further light on the effectiveness of ESI for delaying or preventing surgery.
The study authors are Koltsov; Alicia Zagel, Ph.D.; Matthew Smuck, M.D.; and Serena Hu, M.D., of Stanford University School of Medicine in Palo Alto, Calif.
More than 3,000 spine professionals are meeting at the NASS 2017 Annual Meeting to share the latest information, innovative techniques and procedures, best practices, and new technologies in the spine field. NASS is a multidisciplinary medical organization that fosters high-quality, evidence-based, ethical spine care by promoting education, research, and advocacy. NASS is comprised of more than 8,000 members from several disciplines, including orthopedic surgery, neurosurgery, physiatry, neurology, radiology anesthesiology, research, and physical therapy.