A Clinical Study of Degenerative Spondylolisthesis.

Ra, Young Shin; Kim, Young Soo

Original Article

Journal of Korean Neurosurgical Society 1987;16(2): 425-438.

Department of Neurosurgery, College of Medicine, Yonsei University, Seoul, Korea.

ABSTRACT

The author has studied 125 patients of degenerative spondylolisthesis at the department of Neurosurgery YUMC Severance and Yongdong Severance hospitals from 1975 to Sept. 1986, and also analized the outcome of 72 operated patients. The results were summarized as followings : 1) Male to female ratio was 1 : 3 mean age was 55.5 years old. 2) On L-spine X-ray study, the "Pedicle-Facet angle" between pedicle and inferior articular facet at the slipping level was significantly widened, compared to the angle at the above and below level. It was 113.8 degrees in average at L4-5 level. "Pedicle-Facet angle" and the degree of slipping were in directly proportional relationship(Y=0.51X+107.2, r=0.35). The wider the angle is, the more slipping develops. 3) As the results from the above, etiologic factor of pathogenesis in degenerative spondylolisthesis is considered as that the widening of "Pedicle-Facet angle" had been congenital, is more increased when the severe degenerative change of posterior articulation develops as aging process. 4) The most characteristic symptom was neurogenic intermittent claudication(91.2%). There were few neurological abnormal findings. Common abnormal signs were loss or decrease of ankle reflex(81.6%) and limited backward bending(73.6%). The SLR test, characteristic sign of soft disc herniation, was not significant in this degenerative spondylolisthesis. 5) The degenerative spondylolisthesis developed most frequently at L4-5 level(84%), next at L5-S1(6.4%) and L3-4(4.8%). 6) On L-spine X-ray study, the average extent of displacement was about 7mm, ranging from 5 to 9mm in most cases. The average degree of slipping against the A-P diameter of the vertebral body was about 16%, mostly in the range of 11 to 20%. Almost all the cases(96.8%) fell into Grade I category by Meyerding classification. 7) On myelogram, the finding of complete or incomplete block was present in 71%, and simple indentation of contrast dye column in 29%. Among the patients with incomplete block, the cases in which contrast media passed with lumbar flexion and completely obstructed with extension, compared 53.3%. 8) Spine CT myelography was most important in the diagnosis of the stenosis of spinal canal, the degree of disc herniation, and the cauda equina compression. 9) The commonest findings on spine CT scan were pseudoherniation of disc and lumbar spinal stenosis. And vacuum facet phenomenon(57.3), hypertrophy of facet joint(50.8%), and osteophyte formation(49.1%) were also found. 10) The prefered method of operation was wide decompressive laminectomy of the adjacent vertebrae at slipping level, medial facetectomy and foraminotomy. And in most cases, vertebral interbody fusion was not needed(90.3%). 11) There were 4 cases(5.6%) of further slipping following laminectomy, and anterior interbody fusion were performed in two of them. 12) The results of surgery were Good to Excellent in 88.9% and Fair to poor in 11.1%.