INAPPROPRIATE MRI USE IN THE DIAGNOSIS OF ACUTE SCIATICA

Magnetic resonance imaging (MRI) is a resource that warrants judicious use in Canada. Sciatica is a painful and debilitating condition resulting from compression (often from a herniated disc) of lumbosacral nerve roots. For most patients, this condition is self-limiting and resolves within 6 to 12 weeks. Given the high sensitivity and specificity of the diagnosis based on patient history and physical exam (90% and 71%, respectively), many would argue that MRI is not necessary in the diagnosis of acute sciatica. The goal of this study was to identify the incidence of MRI use in patients from an acute sciatica clinic, and then to elucidate any cost and time savings that could be realized by more appropriate MRI allocation. Patients were referred primarily from the emergency department and from primary care, after meeting our set inclusion criteria. All patients were seen within 4 weeks of their first presentation of sciatica, and were seen and assessed by a spine surgeon in our acute sciatica clinic. Incidence of MRI use in surgical and non-surgical patients was calculated. Of 128 patients enrolled in our study, 15 (12%) required surgical intervention while 113 (88%) experienced spontaneous resolution of their sciatica. Of the 113 patients that experienced spontaneous resolution, 49 (43.5%) received an MRI. Further to this, 11 (9%) non-surgical patients received an additional MRI. Understandably, 15 (100%) of surgical patients received an MRI. However, within the surgical population 7 (47%) patients received an additional MRI prior to surgery. Given the cost-estimate of $750CDN per MRI, $50,250 was the total cost for these 67 MRIs. No patients became surgical as a result of MRI findings. It is apparent that a large proportion of our patients, both surgical and nonsurgical, may have received an unnecessary MRI. Specifically, there were up to 67 potentially unnecessary MRIs conducted within just 128 patients in this study. The patients in this study met the inclusion criteria with a high sensitivity and specificity for sciatica, and in the absence of other spinal conditions. While some MRI usage in this non-surgical population may have been warranted, it is unlikely that the significant number of scans are justifiable. In a conservative cost estimate (excluding time in scanner, tech time, and radiologist time), $50,250.00 could have been saved. It is unclear what leads to the overuse of MRI in the work up for acute sciatica. Perhaps diagnostic uncertainty in some referring doctors is contributing. This study suggests that a clinic dedicated to the treatment of acute sciatica could have immediate benefits in health care resource allocation.