当院における外側型腰椎椎間板ヘルニアの検討

抄録

Between June, 1994 and July, 2003, a total of 370 patients underwent lumbar discectomy for herniated nucleus pulposus. Twenty-two patients (5.9%) were diagnosed as having extraforaminal lumbar disc herniation (ELDH). The average age at the time of surgery was 55.4 years. The level was L2/3 in one case, L3/4 in five cases, L4/5 in nine cases, and L5/S1 in seven cases. Myelography was normal in 14 cases and abnormal in eight cases. However, ELDH was not diagnosed. In only one out of 17 cases, ELDH could not be detected on magnetic resonance imaging (MRI). Selective nerve root block was performed in 16 cases. Pain was reproduced and clinical symptoms improved transiently by nerve root block in all cases. Accurate diagnosis of ELDH was achieved with CT-discography (CTD) in 12 out of 12 cases (100%). Myelography is basically of no value as a diagnostic technique for ELDH. MRI more or less clearly demonstrates the pathology, but present certain cases as false normal. Selective nerve root block is useful for diagnosis at the pathological level. CTD is an excellent diagnostic technique for ELDH, but in order to identify ELDH, it has to be performed whenever myelography is normal or equivocal. In all cases, we performed resection of herniated discs following lateral fenestration. Clinical symptoms improved in all cases after surgery.
Accurate preoperative diagnosis estimated by CTD is crucial in order to obtain satisfactory operative results.