[Non-union after a vertical fracture of the sacral central zone with a conical dislocation of the pelvic ring].

Abstract A longitudinal (vertical) fracture of the sacrum passing through the central sacral canal is a very rare injury, reported in the literature mostly as case reports. Out of 24 reference found, non-union associated with this fracture has been reported only once. A longitudinal fracture of the sacrum is always associated with injury to the anterior pelvic ring. Conical instability of the pelvis, little known so far, occurs if only the anterior ring of the pelvis is stabilised and early weight-bearing is established. It is demonstrated by opening of the distal part of a sacral fracture and, in the case of symphyseolysis, also by opening of the distal part of the symphysis. Therefore, in this type of fracture, both the anterior and posterior pelvic arches should be stabilised at the same time. Iliosacral screws applied percutaneously are optimal for osteosynthesis of sacral longitudinal fractures; sacral bars could be used as well. By means of this procedure, painful instability of the posterior pelvic segment and non-union in this area can be prevented. This case report describes the successful treatment of a 46-year-old male patient injured in a motorbike accident. Despite stabilisation of the pubic symphysis using a plate and locking screws, the patient developed a pseudoarthrosis of the sacrum with implant failure within 6 months of surgery. For that reason, the sacrum was stabilised by two iliosacral screws in a combination with a sacral bar at the S1-S2 level. The implants were introduced percutaneously using CT guidance. Stabilisation of the anterior part of the pelvis was performed by using a supra-acetabular external pelvic fixator; the original implant was left in situ. Consequently, the sacral non-union healed within one year.