How can osteosynthesis material used for fracture fixation undergo intrathoracic migration?-a systematic literature review.

Background: Kirschner wires or pins were widely used for osteosynthesis in trauma surgery. Breakage of osteosynthesis material and intra-thoracic migration is a complication that has occasionally been described. We reviewed the literature to study the frequency and pathophysiology of such migrations. Methods: PubMed and Embase databases were searched for reports of intrathoracic osteosynthesis material migration. Cases were divided according to specific anatomic regions. We studied the time interval between initial operation, types of osteosynthesis material, intactness and trajectory of the material. Operative techniques and the outcome of material retrieval were analyzed. Results: Of 3,592 potential articles, 102 manuscripts met all inclusion criteria describing 112 individual cases for a total of 124 different migrations. Risk of reporting bias was high. Osteosynthesis material predominately migrated into lung (29.0%), mediastinum (24.2%), major vessels/heart (18.5%), pleural space (9.7%) or spinal canal (13.7%). Migration occurred from four anatomical regions but predominantly the shoulder girdle (73.2%). The migration trajectory was not always predicable. We found that migration was linear in 83.8% (odds ratio 4.8, P=0.002) of reported cases if the origin was the clavicle compared to other regions. Intrapulmonary migrations were associated with a linear trajectory of intact material, while intrapleural migration were associated with non-linear migration of broken material. More than half of all reported migrations (51.8%) occurred later than one year after osteosynthesis, ranging from three days to 360 months. Major open surgery was performed for extraction in 66.9% of cases, video-assisted thoracoscopic surgery (VATS) 14.4% and local shoulder/neck incisions in 12.7%. Intra-thoracic migration was fatal in 4.5%. For osteosynthesis material retrieval from pulmonary parenchyma, VATS was used in only 25% and resulted in shorter hospital stays (T=-1.542, P=0.07), 3.2 days (W=0.890, P=0.47) compared to 6.2 days (W=0.879, P=0.056) for open surgery. Conclusions: Intrathoracic migration of intact or broken Kirschner wires is not rare and potentially fatal. Migration trajectories and destination are difficult to predict. Systematic long-term radiological follow-up of such osteosynthesis material seems warranted. This review suggests that all intrathoracically migrated osteosynthesis material should be surgically removed. Minimally invasive approaches (VATS) should be considered whenever anatomy and clinical presentation allow this.