The Impact of the Placement of the L5 Vertebra in Relation to the Intercrest Line on the Level of Disc Herniation.

Abstract

To determine whether there is a correlation between a deeply seated L5 vertebra in relation to the intercrest line (ICL) and the level of degeneration of lumbar discs. The study included 152 patients who underwent surgery for lumbar disc herniation. After analyzing the radiographs, the patients were separated into two groups. Group 1 patients had an ICL that passed through the L4 corpus, and Group 2 patients had an ICL that passed through the L4-5 disc distance or the L5 vertebra. Group 1 patients were classified as having a deeply seated L5 vertebra, while Group 2 patients were classified as not having a deeply seated L5 vertebra. The study found that male patients had a significantly higher incidence of a deeply seated L5 vertebra compared to female patients (p=0.003). Patients who underwent surgery at the L4?5 level exhibited disc heights that were notably higher than those who underwent surgery at the L5-S1 level. In Group 1, 68% of the patients had surgery at the L4-5 level, compared to only 41.7% in Group 2 (p=0.009). When investigating the effects of the position of the L5 vertebra in relation to the ICL at the L4-5 and L5-S1 disc levels, the study found that having a deeply seated L5 vertebra protected against L5-S1 disc herniation and that L4-5 disc herniation was more common in these patients. This is believed to be due to the L5?S1 segment being less mobile when the L5 vertebra is deeply seated.