Magnetic resonance–guided percutaneous laser disk decompression for lumbar disk herniation—relationship between clinical results and location of needle tip

Abstract

Background Magnetic resonance–guided PLDD has been performed for patients with single-level contained focal disk herniation. We investigated the clinical results of our PLDD practice in reference to the site of the needle tip. Methods Thirty-two patients (24 male patients and 8 female patients; mean age, 35 years) who presented with low back pain and signs of monoradiculopathy underwent MR-guided PLDD. The final location of the needle tip was plotted on a T 1-weighted axial plane of the targeted disk. An axial image of the targeted disk was divided into 4 quadrants in a cruciform fashion and into 3 zones in a concentric circle. The clinical results as evaluated by MacNab's criteria 6 months after PLDD were investigated in each subdivided area where the needle tip was located. Results The overall success rate of our PLDD practice was 68.8%. The success rate in the 27 patients who had the needle tip in the DL quadrant of the targeted disk was 70.4%. Among them, 14 patients who had the needle tip in the middle zone showed a favorable outcome (77.8%). Conclusions The final location of the needle tip was demonstrated in all cases. Although our MR imaging study was not sufficient to determine the exact position of the needle tip because of MR image distortion, such error seems to be acceptable in the results of our study obtained from the relative positioning of the needle tip in the disk space. This study suggests that the middle zone in the DL quadrant of the targeted disk space seems to be a favorable target to obtain better clinical outcomes.