Background & Objective: Determining the level of lesion in lumber disc disease might be difficult, especially when there is a transitional vertebrae. MRI is one the methods widely used in presurgery however, presence of sacralization or lumbarization may lead to a incorrect diagnosis. This study aimed at evaluating the agreement degree between the results of MRI and surgery with the post-operative radiographic findings in patients with lumber disc herniation.

 Methods: Thirty patients with lumber disc herniation were evaluated in a diagnostic value study during a 15-month period of time. Presurgery MRI results, as well as the findings during operation regarding the level of herniated lumbar disc were compared with the radiographic findings, numbering the vertebra below the C2 after surgery. The radiologic assessment of involved segment was considered as the gold standard method. Transitional vertebrae were determined on the basis of radiologic findings.

 Results: There were thirty patients with lumber disc herniation, 16 males and 14 females, with the mean age of 40.83±12.57 years in the study. There was a high and significant degree of compatibility agreement between the results of MRI and findings during surgery with the radiologic data (kappa=0.719, p<0.001 kappa=0.859, p<0.001). The results of MRI and surgery were incorrect in 4 and 2 cases, respectively. All these cases had a transitional vertebra in lumbosacral segment (totally 6 patients with transitional vertebra) i.e. MRI and surgery were able to detect the right level of herniation in 33.3% and 66.7% of patients with either sacralization or lumbarization, respectively. The sensitivity of MRI and surgery was 87% and 93%, respectively.

 Conclusion: Our results showed that MRI and surgery can reveal the right level of LDH in majority of patients however, when there is a transitional vertebra, this ability may significantly be decreased.