Abstract
Study Design: A prospective evaluation of 40 consecutive patients with sciatica who had ‘Normal’ MRI scans, were further investigated with Nerve Root Injections (NRI), and subsequent surgery in those who had relief of symptoms.
Objectives: To evaluate the diagnostic value of NRI’s in the presence of normal MRI scans and to assess the aetiology of the sciatica.
Summary of Background Data: Since the advent of MRI scans the use of NRI’s has been in decline as a diagnostic tool. There has been no study in their usefulness when the MRI has been reported as showing no evidence of nerve root compression, and furthermore what the surgical findings were in the patients who went on to exploration.
Methods: 40 Patients with sciatica, of minimal duration of one year, in whom the MRI scan had been reported as showing no evidence of nerve root compression by an independent observer, had diagnostic NRI’s performed. Those patients that had reproduction of and subsequent temporary relief of their sciatica had surgery.
Outcome Measures: Walking distance, Analgesic Requirements, Sleep disturbance and VAS.
Results: Of the 40 patients, 25 had no benefit, 4 patients had permanent relief and 11 had temporary relief. These 11 patients underwent surgery. All patients undergoing surgery were L5 nerve root explorations. In 9 cases the compression was by the ligamentum flavum and in 2 at the foramen. Of the eleven cases operated on 9 had complete relief of symptoms and 2 were unchanged.
Conclusions: MRI scans do not show a cause for sciatica in all patients as it is not a dynamic test. In the presence of a normal MRI scan, NRI’s should be performed.
These abstracts were prepared by Mr. Brian J C Freeman FRCS (Tr & Orth). Correspondence should be addressed to him at The Centre for Spinal Studies and Surgery, University Hospital, Queens Medical Centre, Nottingham NG7 2UH.
