- Discussion:
- involves a congenital insufficiency of facet joints (of S1 or L5) & disk complex, resulting
in displacement w/o a defect or elongation of pars interarticularis;
- there is gradual attenuation of the pars interarticularis, but no gap or defect in pars interarticularis;
- fifth lumbar facets appear to subluxate ventrally on the sacral facets;
- pedicles may appear elongated as well, & they may further contribute to the forward subluxation;
- when slip is severe, however, a defect may appear in the center;
- these pts are more prone to recurrent symptoms and clinical deformity if forward slipping is allowed to progress;
- Clinical Findings:
- neurologic injury:
- there is a high occurance of nerve root pressure due to intact lamina of
L5 being pulled against dural sac;
- significant neurologic impairment may occur in presence of only minor degrees of slip;
- pts are at risk for cauda equina dysfunction because neural arch is intact;
- gait: pt's abnormal gait is secondary to hamstring tightness;
- Radiographs:
- lateral x-rays may show that the entire posterior neural arch of L5 appears to slide ventrally;
- if lamina and posterior elements remain intact, spondylolisthesis is limited to 25 per cent of the width
of the first sacral vertebra;
- myelography is indicated in pts w/ bladder or bowel dysfunction or w/ neurologic deficit
Surgical treatment of dysplastic spondylolisthesis. Results after in situ fusion.