Abstract
Lumbar tumors of the ligamentum flavum have traditionally been considered a rare cause of nerve root or spinal canal compression, but in recent years, with the advent of MR imaging, more tumors have been discovered. This study reports on the clinical features of recognizable symptomatic lumbar tumors of the ligamentum flavum in 19 patients, as determined by MR imaging. Patients were studied from January 1997 to October 2000. Clinical Sample: Our sample population 19 patients was composed of 11 men and 8 women (average age of 65.3 years, ranging from 39-82 years). Two tumors were located at L2/3, 4 tumors at L3/4, 9 tumors at L4/5, 1 tumor at L5/6, and 3 tumors at L5/S1. Seventeen patients underwent surgery, with the average period for surgery from symptom onset being 12 months (ranging from 1-78 months). We examined symptoms, imaging studies, surgical procedures, results and pathological findings. Nine patients presented with radiculopathy and 10 patients presented with cauda equinopathy; six patients complained of low back pain. Standard X-rays of the lumbar spine revealed some instability in 12 patients (63.1%). Five of 9 myelograms revealed the interruption of the root sleeve in those patients suffering from radiculopathy, while the others exhibited central stenosis. All myelograms revealed central stenosis in those patients suffering from cauda equinopathy. Twelve of 13 facetgrams revealed masses, and in combination with CT scan, the location and size of the tumors could be determined. On MR imaging, iso intensity on T1-weighted images, high intensity on T2-weighted images, and ling enhancement on Gd-enhanced T1-weighted images are the most common views for tumors. Surgical Procedures: A wide fenestration was performed on 6 patients, a hemi laminectomy was performed on one patient, and a hemi wide fenestration was performed on those two patients suffering from radiculopathy. A wide fenestration was performed on 7 patients, and a laminectomy was performed on one patient who suffered from cauda equinopathy. Outcomes: None of these patients experienced a worsening of symptoms following operation. Histological findings revealed 11 ganglions, 3 granulation tissues, 2 hematomas and 1 synovial cyst. Clinical features of the ligamentum flavum tumors are based on its anatomical features, which is dorsal to the dural sac and forms the anterior and medial capsule of the facet joint -- and the degeneration of the ligamentum flavum under segmental instability is the promotional factor of forming tumors.
