Increasing Rates of Imaging in Failed Back
Surgery Syndrome Patients: Implications for
Spinal Cord Stimulation
Publication
, Journal Article
Lad, SP
Published in: Pain Physician
Background: Failed back surgery syndrome (FBSS) has a high incidence following spinal surgery, is
notoriously refractory to treatment, and results in high health care utilization. Spinal cord stimulation
(SCS) is a well-accepted modality for pain relief in this population; however, until recently magnetic
resonance imaging (MRI) was prohibited due to risk of heat conduction through the device.
Objectives: We examined trends in imaging use over the past decade in patients with FBSS to
determine its impact on health care utilization and implications for patients receiving SCS.
Study Design: Retrospective.
Setting: Inpatient and outpatient sample.
Methods: We identified patients from 2000 to 2012 using the Truven MarketScan database. Annual
imaging rates (episodes per 1000 patient months) were determined for MRI, computed tomography
(CT) scan, x-ray, and ultrasound. A multivariate Poisson regression model was used to determine
imaging trends over time, and to compare imaging in SCS and non-SCS populations.
Results: A total of 311,730 patients with FBSS were identified, of which 5.17% underwent SCS
implantation (n = 16,118). The median (IQR) age was 58.0 (49.0 – 67.0) years. Significant increases in
imaging rate ratios were found in all years for each of the modalities. Increases were seen in the use
of CT scans (rate ratio [RR] = 3.03; 95% confidence interval [CI]: 2.79 – 3.29; P < 0.0001), MRI (RR
= 1.73; 95% CI: 1.61 – 1.85; P < 0.0001), ultrasound (RR = 2.00; 95% CI: 1.84 – 2.18; P < 0.0001),
and x-ray (RR = 1.10; 95% CI: 1.05 – 1.15; P < 0.0001). Despite rates of MRI in SCS patients being
half that in the non-SCS group, these patients underwent 19% more imaging procedures overall (P <
0.0001). SCS patients had increased rates of x-ray (RR = 1.27; 95% CI: 1.25 – 1.29), CT scans (RR =
1.32; 95% CI: 1.30 – 1.35), and ultrasound (RR = 1.10; 95% CI: 1.07 – 1.13) (all P < 0.0001).
Limitations: This study is limited by a lack of clinical and historical variables including the complexity
of prior surgeries and pain symptomatology. Miscoding cannot be precluded, as this sample is taken
from a large nationwide database.
Conclusions: We found a significant trend for increased use of advanced imaging modalities
between the years 2000 and 2012 in FBSS patients. Those patients treated with SCS were 50% less
likely to receive an MRI (as expected, given prior incompatibility of neuromodulation devices), yet 32%
and 27% more likely to receive CT and x-ray, respectively. Despite the decrease in the use of MRI in
those patients treated with SCS, their overall imaging rate increased by 19% compared to patients
without SCS. This underscores the utility of MR-conditional SCS systems. These findings demonstrate
that imaging plays a significant role in driving health care expenditures. This is the largest analysis
examining the role of imaging in the FBSS population and the impact of SCS procedures. Further
studies are needed to assess the impact of MRI-conditional SCS systems on future trends in imaging
in FBSS patients receiving neuromodulation therapies.
