Preoperative Magnetic Resonance Imaging Modifies Percutaneous Spinal Cord Stimulator Trial Progression and Planning

Spinal cord stimulator (SCS) percutaneous lead placement has been effective in treating chronic limb, neck, and back pain. However, SCS lead placement poses a risk of neurologic injury, which may be attenuated with preprocedural magnetic resonance imaging (MRI) to identify potential spinal anatomical abnormalities (eg, central canal stenosis) that would either modify or prevent lead placement. However, a large-scale study of the clinical value of preoperative MRIs in percutaneous SCS lead placement is lacking.

A retrospective chart review of a single center identified patients who considered SCS percutaneous lead trials and had preprocedural MRIs. Patients' preprocedural MRIs were reviewed for spinal pathology and locations and severity of stenoses (mild, moderate, and severe) based on qualitative analysis that may affect lead placement. In addition, trial-related information and several demographic factors were analyzed with proportional analyses, logistic regressions, and relative risks (RR) to determine their association with stenosis.

Retrospective review identified 340 patients who considered an SCS trial with preprocedural MRIs. Preprocedural MRIs influenced SCS treatment for 7% of total patients (n = 25). Of these 25 patients, 60% (n = 15) had the trial technique altered, and 40% (n = 10) did not progress to trial owing to an MRI finding. Preprocedural MRIs were more likely to influence SCS trials for cervical cases than for thoracic/lumbar cases (RR = 4.6, 95% CI 2.2-9.5, p < 0.001). Clinical and demographic characteristics were associated with limited predictive capabilities for spinal stenosis. Specifically, logistic regression analyses revealed age group to be significantly (p ≤ 0.02) associated with moderate/severe cervical spinal stenosis and lumbar spinal stenosis, whereas only age was significantly (p ≤ 0.04) associated with moderate/severe thoracic spinal stenosis.

Preprocedural MRIs did influence SCS trial progression. Given limited patient characteristics were significantly associated with a greater risk of stenosis at lead placement or entry zones, all patient populations should be considered for preprocedural MRIs examining lead entry and placement zones.