H. Tonami et al., PERCUTANEOUS LASER DISKECTOMY - MR FINDINGS WITHIN THE FIRST 24 HOURSAFTER TREATMENT AND THEIR RELATIONSHIP TO CLINICAL OUTCOME, Clinical Radiology, 52(12), 1997, pp. 938-944
Objective: The purpose of this study was to evaluate the early MR appe
arances of the intervertebral disc obtained within 24 h after percutan
eous laser discectomy and to determine if a correlation exists between
the MR images and the clinical outcome. Subjects and Methods: Twenty-
nine discs in 26 patients with contained lumbar disc herniation treate
d by laser were included, Laser intervention was performed using Ho:YA
G laser system, The results were quantitatively analysed by measuring
areal changes of the herniated mass on axial T1-weighted images and si
gnal changes within the disc on sagittal T2-weighted images, Clinical
outcomes were evaluated according to Japanese Orthopaedic Association
score (JOA score), and recovery rates based on JOA score immediately a
nd 1 year after treatment were calculated. Results: The recovery rate
immediately after treatment was 53.1%, and increasing to 64.6% 1 year
later, The size of the disc herniation ranged from 7% to 55% of the ax
ial cross-section of the spinal canal pre-operatively and no significa
nt changes were noted postoperatively. Also no correlation was found b
etween the pre-operative herniation size and the recovery rate, The si
gnal changes within the disc increased significantly after treatment,
but no correlation was present between the signal changes and the reco
very rate, In five patients, soft-tissue changes along the laser tract
were well demonstrated on MR imaging. Conclusion: Although immediate
postoperative MR imaging shows early tissue changes induced by laser,
our study has not proven that immediate postoperative MR imaging could
predict the clinical outcome after percutaneous laser discectomy.