Magnetic Resonance Imaging Observations of the Conus Medullaris in a Korean Population

STUDY DESIGN: Retrospective study (level of evidence: level 3). PURPOSE: To study the anatomy of the conus medullaris in Koreans. OVERVIEW OF LITERATURE: The anatomical position of the conus medullaris is well-documented in anatomy textbooks; however, the shape of the conus in the canal rarely described. Furthermore, to our knowledge, no study in Korea has not yet assessed the shape of the conus as well as its position in the canal via cadavaric dissection and/or magnetic resonance imaging (MRI). METHODS: MRI findings of 189 Korean patients aged 2–94 years (93 men and 94 women) were assessed. No subjects from other ethnicities were included. The method proposed by Arai and colleagues was used to assess the termination point and shape of the conus in the canal. The position of the intervertebral disc trisection of the vertebral body closest to the tip of the conus was recorded at the canal level. RESULTS: The tip of the conus medullaris was positioned from the upper T12 body to the L2–L3 disc, mostly in L1 bodies (52.4%), followed by the L2 bodies (22.5%), the L1–L2 disc, and the L2–L3 disc (1.1%). The shape of the conus was classified as type A in 74 (39.6%), type B in 58 (31%), and type C in 55 patients (29.4%). The conus did not terminate at the L3 body in any patient. In the first decade ones (five children) conus positioned rather lowly from L1 bodies to L2–L3 disc, and no type A conus shape, and mostly type B (80%). CONCLUSIONS: The conus medullaris was positioned mostly in the lower one-third of L1 and it in the first decades terminated lowly. No type A in the first decade one, and type B was mostly frequently formed which was followed by type C.

Factors Affecting Posterior Angulation in Retrograde Intramedullary Nailing for Distal Femoral Fractures

PURPOSE: To analyze the factors that cause a posterior angulatory deformity in the retrograde intramedullary nailing of distal femoral fractures. MATERIALS AND METHODS: Fifty-five patients with distal femur fractures who were treated with retrograde intramedullary nailing were enrolled in this study. They were followed-up for at least one year postoperatively. The posterior angulatory deformity was evaluated according to the fracture location, pattern, and insertion point and the insertion point was compared with the ideal point derived from the radiographs of 100 normal adults. The correlation between the posterior angulation and the entry point of the nail was analyzed. RESULTS: The posterior angulation was similar in terms of the fracture location; a meaningful difference was noted among the fracture patterns (p=0.047). The posterior angulation was significantly greater when the entry point was located more posteriorly, accepting a malreduced state (p=0.012). CONCLUSION: Posterior angulation was smaller in the transverse fracture and the posterior location of the entry point from the apex of the Blumensaat's line increased the posterior angulation.