[Ventral or dorsal spondylodesis in dens basal fracture--a new classification for choice of surgical approach].

The conservative treatment of the fracture of the densbasis (type 2 according to Anderson and D'Alonzo) bears the risk of developing a pseudarthrosis in about 30%. Therefore the anterior screw fixation according to Magerl/Böhler is general accepted. When the fracture line runs from top back to front base in this method the risk of developing a pseudarthrosis increases. With an own classification in accordance to the run of fracture line type A, B and C is differentiated. In Type A and B the anterior screw fixation is recommended. In case of type C the posterior fusion of the arches C1 and C2 is biomechanically more advisable--it results an axial compression on the fracture fissure. The usefulness of the classification is demonstrated with clinical cases.