Osteonecrosis of the Lumbar Posterior End Plate

Objective:To study the pathogenesis and diagnosis and treatment of the osteonecrosis of the lumbar posterior end plate. Method:There were 21 cases with this disease whose chief symptoms were low back and leg pain. Some patients had intermitten claudication or cauda equina syndrome. The average time were four years and six months. X ray films showed a bony piece from the lumbar posterior vertebra protruding into the spinal canal. CT scanning found a round like or multicystic bony defect with a dense peripheral margin in the lumbar posterior end plate which protruding into the spinal canal and compressing the lumbar nerve root or dura mater. MRI showed that corresponding lumbar disc presented severe degeneration. All cases were operated on. Bony piece protruding into the spinal canal and herniated disc material were removed.Bone grafting and internal fixation were performed in the same segment in some cases. Result: Both of substance of bone protruding into the spinal canal together with peripheral anulus fibrosis and fibrous cartilage tissue with bony material filling in end plate defect area can be seen macroscopically. All 21 cases were followed up for six months to three years,average 18 months. Low back and leg pain disappeared in 18 cases and light low back pain remained in 3 cases. All 3 cases with cauda equina syndrome resumed normal basically. Conclusion:Abnormal stress or overload or other causes lead to lumbar end plate avascular degeneration and necrosis,which appeared shape osteochondral necrosis defect area in end plate. The proliferation and sclerosis appeared in the peripheral osteochondral tissue of the defect area. Proliferating posterior bony margin of the lumbar end plate protruded into the spinal canal to compress nerve root or cauda equina,lead to symptoms and signs of osteonecrosis of the lumbar posterior end plate. The name of the disease asosteonecrosis of the lumbar posterior end platecan reflect its pathologic essence comparatively precisely.