DISC HERNIATIONS AND CAUDA EQUINA COMPRESSION IN BILATERAL OSSEUS AND COMBINED FUSION LUMBOSACRAL TRANSITIONAL ANATOMY TYPES

Abstract

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Background. The relationship between different lumbosacral transitional vertebra (LSTV) types, disc herniations and neural structures compromise has been sporadically reported. Aim. To analyze disc herniations prevalence and distribution and to grade cauda equina compression in the LSTV types with osseus fusion of the last lumbar vertebra. Material and Methods. A total of 75 patients (mean age 55.54±9 years) with lumbosacral radicular syndrome who underwent MRI examination of the lumbar spine were included in the study. These patients were separated in two groups. Study group comprised 29 patients who presented with osseus fusion LSTV; 14 patients with bilateral osseus and 15 of them with combined fusion LSTV type. Forty six patients without LSTV were added randomly and referred to as the control group. Results and Discussion. There were significantly more disc herniations (86%, 87% vs 59.4%, p=0.05) and more severe cauda equine compression (14%, 20% vs 3%, p=0.009, p=0.01) at the level that assumes the role of lumbosacral junction in bilateral osseus and combined fusion group each compared to the control group. At the adjacent proximal level less disc herniations (50%, 53% vs 55.7%) but more severe cauda equina compression (36%, 27% vs 21%) was observed in both LSTV groups, each compared to the control group. Conclusions. In conclusion, altered morphology and biomechanics in osseus fusion LSTV types provoke disc herniations and severe cauda equina compression to occur more frequently proximal to the level of transition.