Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P27. The phenomenon of temporary increase of herniated disc on dynamic MRI control

Abstract

BACKGROUND CONTEXT MRI is an objective and basic method of diagnosing a herniated disc. In terms of hernia size, most specialists decide on the tactics of further treatment (try conservative therapy or surgery). And certainly all specialists seeing in the dynamics of an increase in hernia size interpret this as an indication for the surgical intervention. In our study, we show that an increase in the size of a hernia and a simultaneous change in its signal characteristics may precede its further decrease. PURPOSE To break the paradigm that increase of herniated disc on MRI is always an indication for surgical intervention. STUDY DESIGN/SETTING Prospective observational study. OUTCOME MEASURES Dynamics of changes in the size of herniated disc and its signal chatacteristics in MRI images. METHODS The study included 135 patients with an intervertebral extrusion present in the L4-5, L5-S1 segments aged 35–55years, 73 of them men and 62 women. In all patients, the intervertebral hernia was diagnosed within 3 months preceding the start of the study. The average extrusion size was 8.8 mm. All patients received gabapentin as an analgetic. An MRI was performed 3times with a 30-day interval. Assessment of the dynamic of patient improvement was performed using short programs: MRI: – T2 sagittal – TR=4,490 ms, TE=121 ms, dist. factor (slice gap) 0%, FOV=300 mm, slice thickness=3 mm; - T2 transversal - TR=7,530 ms, TE=124 ms, dist. factor (slice gap) 0%, FOV=180 mm, slice thickness=3 mm. RESULTS Patients were divided into two groups based on the character of the dynamic changes seen in the signal characteristics of disc hernias: (1) increase in signal (diffuse or focal) from the disc, with significant increase in the size of the hernia (2–5 mm), which can be caused by inflammatory edema and neovascularization. The increase in size could be regarded as a negative dynamic, but further observation within 90days after the first MRI showed a decrease in the size of the hernia (3-7 mm) and an improvement of the clinical symptoms in 89 patients; and (2) in 46 patients, the disc signal did not change, neither did the size of the hernia, which resulted in surgical intervention being indicated for herniated disc removal. CONCLUSIONS The active change in the structure and especially the size of the hernia in a relatively short time interval (1–2 months) should not serve as an absolute indication for surgical intervention, as our study has shown, in the majority of patients the hernia regresses over the next few months. This phenomenon requires further immunobiological studies. It is also necessary to systematize the enormous information obtained in MRI diagnostics (not only in size, but also in structure) into a single classification unified for all specialists dealing with the problem of low back pain, which will reduce the number of unreasonable surgical interventions.