Suk Hong MD, PRESENTER: Nothing to Disclose

Abstract: HTML Purpose: To determinate the MR findings of extraforaminal stenosis (EFS) in lumbosacral junction (LSJ) in patients whom underwent foraminal or extraforaminal decompressive surgery. Methods and Materials: Between November 1996 and Mrach 2003, there were 50 patients whom underwent decompressive surgery for foraminal (n=18) or EF (n=32) stenosis in LSJ by 1 experienced neurosurgeon. Forty six patients excluding 4 patients who had unavailable preoperative MR scans were retrospectively analyzed to determine the diagnostic MR findings of the EFS in LSJ. The following MR criteria was used for the diagnosis of the EFS in LSJ: 1) EF site: lateral to the lateral edge of ligamentum flavum or lateral border of pedicle in axial and sagittal MR scans, 2) Stenosis: perineural fat plane obliteration, additionally nerve root swelling. The following imaging findings were evaluated as the causes of the EFS in LSJ: lumbar scoliosis, large L5 transverse process or sacral ala, intervertebral osteochondrosis in L5-S1 level, LS assimilation joint with/without osteoarthritis. The last 10 patients were evaluated with additional oblique coronal T1WI MR scan. The MR findings were correlated with the operative results. Results: The sensitivity, specificity, positive and negative predictive values of the MR findings of the EFS in LSJ were 93.5%, 33.3%, 74.4%, and 71.4%. The sensitivity and positive predictive value were 100%, 90% respectively, when we evaluated with the additional oblique coronal T1WI. The EF nerve root was compressed by osteophyte of L5 lower endplate and L5 transverse process or sacral ala in all cases. The ipsilateral concave scoliosis in LSJ was 53.3%, 80.1%, ipsilateral large L5 transverse process was 60%, 83.9%, ipsilateral large sacral ala was 53.3%, 25.8%, ipsilateral LS assimilation joint was 26.7%, 54.8%, osteoarthritis in LS assimilation joint was 26.7%, 41.9%, and ipsilateral severe asymmetric intervertebral osteochondrosis was 60%, 70.1%, in foraminal, EF stenosis, respectively. Conclusion: The EFS in LSJ can be correctively diagnosed with the analysis of the MR findings. The causes of EFS in LSJ were osteophyte of L5 lower endplate, L5 transverse process, and sacal ala. The associated imaging findings were ipsilateral concave lumbar scoliosis in LSJ, large L5 transverse process, and LS assimilation joint.      

Hong MD, S, Extraforaminal Stenosis in Lumbosacral Junction: New MRI Findings Correlated with Surgical Findings.  Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL. http://archive.rsna.org/2003/3108489.html