The Etiology of Spondylolisthesis

The history of the recognition of spondylolisthesis and of the illvestigation iIltO its cause makes interesting reading. Herbiniaux (1782), a Belgian obstetrician, was possibly the first to draw attention to this lesion, although in 1741 Andry had described the cause ofa hollow back as a warping of the spine inwards. Originally attention was attracted to it as a cause ofobstruction in labour. During the early part ofthe nineteenth century a few workers found specimens of gross displacement. From anatomical dissections they concluded that it was due either to a congenital deformity or to some disease in the lumbo-sacral disc. At that time it was described as a luxation of the lumbo-sacral joint. Kilian (1854) thought that this term was not correct. He pointed out that it was due to a slow displacement of the last lumbar vertebra and coined the term spondylolisthesis. Up to 1 855 those interested in the subject seemed to be satisfied to accept the condition as a slow slipping of the last lumbar vertebra due to superimposed body weight. But Robert (1855), by careful dissection and freeing the fifth lumbar vertebra of all soft tissues, showed that it was impossible for the vertebra to slip so long as the neural arch remained intact. He demonstrated that if the neural arch was cut the vertebra was free to slip. This is the first indication of the focusing ofattention on a lesion of the neural arch. Suspicion that there was such a lesion was confirmed in 1858 by Lambl, who demonstrated discontinuity in the pars interarticularis in a few cases. Hartmann (1865) noticed that although the body of the vertebra slipped forward the spinous process remained in the same place, thus indicating that there was a division in the neural arch. Neugebauer (1881) stated that the deformity consisted of an elongation and angulation of the sagittal axis of the vertebra mainly in the interarticular portion, but made no mention of a loss of continuity of the bone. This in the light of modern knowledge proves to be correct, for it is evident that the only cases ofspondylolisthesis which these early workers found at post-mortem examination were those of gross displacement-examples of a group exhibiting marked displacement without discontinuity of bone. Controversy then arose about the cause of this elongation in the pars interarticularis and confusion followed the discovery in some cases of a break in continuity, for it was not apparent at the time that two entirely different pathological conditions were under discussion. Neugebauer (1888), then becoming engrossed in this subject, travelled through Europe examining anatomical specimens of spinal columns. He discovered in some a lesion of continuity in the pars interarticularis, with or without forward displacement of the vertebral body. In ten specimens of gross displacement which he termed spondyloptosis he found fractures of the sacral facets or lesions of the interarticular portion of the neural arch. At first he thought that trauma was the most likely cause of the interarticular defect, but he later became persuaded that it was congenital, from an abnormality