Eight adults who had back pain and sciatica that was caused by Grade-III
or IV isthmic spondylolisthesis of the fifth lumbar vertebra on the sacrum
were treated consecutively by in situ arthrodesis without decompression.
The anterior displacement of the fifth lumbar vertebra averaged 82 per cent
(range, 66 to 118 per cent). The length of follow-up averaged 5.5 years
(range, two to fourteen years). All of the arthrodeses resulted in a solid
fusion and excellent relief of both the back pain and the sciatica. All of
the preoperative neurological deficits resolved, with the exception of a
decreased or absent Achilles-tendon reflex in two patients. There were no
complications, and all of the patients returned to their preoperative
occupations.