Jensen M C, Brant-Zawadzki M N, Obuchowski N, Modic M T, Malkasian D, Ross J S
Hoag Memorial Hospital, Newport Beach, Calif. 92663.
N Engl J Med. 1994 Jul 14;331(2):69-73. doi: 10.1056/NEJM199407143310201.
The relation between abnormalities in the lumbar spine and low back pain is controversial. We examined the prevalence of abnormal findings on magnetic resonance imaging (MRI) scans of the lumbar spine in people without back pain.
We performed MRI examinations on 98 asymptomatic people. The scans were read independently by two neuroradiologists who did not know the clinical status of the subjects. To reduce the possibility of bias in interpreting the studies, abnormal MRI scans from 27 people with back pain were mixed randomly with the scans from the asymptomatic people. We used the following standardized terms to classify the five intervertebral disks in the lumbosacral spine: normal, bulge (circumferential symmetric extension of the disk beyond the interspace), protrusion (focal or asymmetric extension of the disk beyond the interspace), and extrusion (more extreme extension of the disk beyond the interspace). Nonintervertebral disk abnormalities, such as facet arthropathy, were also documented.
Thirty-six percent of the 98 asymptomatic subjects had normal disks at all levels. With the results of the two readings averaged, 52 percent of the subjects had a bulge at at least one level, 27 percent had a protrusion, and 1 percent had an extrusion. Thirty-eight percent had an abnormality of more than one intervertebral disk. The prevalence of bulges, but not of protrusions, increased with age. The most common nonintervertebral disk abnormalities were Schmorl's nodes (herniation of the disk into the vertebral-body end plate), found in 19 percent of the subjects; annular defects (disruption of the outer fibrous ring of the disk), in 14 percent; and facet arthropathy (degenerative disease of the posterior articular processes of the vertebrae), in 8 percent. The findings were similar in men and women.
On MRI examination of the lumbar spine, many people without back pain have disk bulges or protrusions but not extrusions. Given the high prevalence of these findings and of back pain, the discovery by MRI of bulges or protrusions in people with low back pain may frequently be coincidental.
腰椎异常与腰痛之间的关系存在争议。我们对无背痛人群的腰椎磁共振成像（MRI）扫描结果中异常发现的患病率进行了研究。
我们对98名无症状者进行了MRI检查。扫描结果由两名不了解受试者临床状况的神经放射科医生独立解读。为减少解读研究时的偏倚可能性，将27名背痛患者的异常MRI扫描结果与无症状者的扫描结果随机混合。我们使用以下标准化术语对腰骶部的五个椎间盘进行分类：正常、膨出（椎间盘超出椎间隙的周向对称延伸）、突出（椎间盘超出椎间隙的局灶性或不对称延伸）和脱出（椎间盘超出椎间隙的更极端延伸）。还记录了非椎间盘异常，如小关节病。
98名无症状受试者中，36%的人所有节段椎间盘均正常。将两次解读结果平均后，52%的受试者至少有一个节段膨出，27%有突出，1%有脱出。38%的人有一个以上椎间盘异常。膨出的患病率随年龄增加而升高，但突出的患病率并非如此。最常见的非椎间盘异常是许莫氏结节（椎间盘疝入椎体终板），见于19%的受试者；环状缺损（椎间盘外层纤维环破裂），见于14%；小关节病（椎体后关节突的退行性疾病），见于8%。男女的检查结果相似。
在腰椎MRI检查中，许多无背痛的人有椎间盘膨出或突出，但无脱出。鉴于这些发现以及背痛的高患病率，MRI在腰痛患者中发现膨出或突出可能常常是巧合。
