Pathogenetic phenotypes of bone cement implantation syndrome in pediatric oncology patients: Case reports

Bone cement implantation syndrome in pediatric oncology patients remains poorly understood. A multimodal pathogenetic model determines the existence of two distinct clinical and pathophysiological phenotypes of this condition: the anaphylactic phenotype (distributive shock) and the embolic phenotype (obstructive shock). Both phenotypes are associated with coagulopathy, with thrombotic catastrophes representing their most severe manifestation. The pathways of thrombotic complications depend on the clinical and pathophysiological phenotype of this critical condition: in anaphylactic bone cement implantation syndrome, they are primarily driven by microthrombogenesis, whereas in embolic bone cement implantation syndrome, both microthrombogenesis and fibrinogenesis contribute to thrombosis. In the first clinical case, bone cement implantation syndrome developed through an anaphylactic mechanism. A boy with femoral osteosarcoma underwent bone cement spacer implantation following tumor resection. We assume that sensitization occurred during this period. This is supported by the presence of a periosteal reaction in the upper third of the right femur, as revealed by computed tomography (CT). During knee endoprosthesis implantation, the patient developed severe hemodynamic instability, cardiac rhythm disturbances, and oxygenation impairment. Despite the characteristic microthrombogenesis mechanism of this pathophysiological phenotype, multiorgan failure and life-threatening thrombotic complications were successfully averted due to effective anti-shock measures and early initiation of heparin therapy. Second clinical case illustrates the embolic phenotype of bone cement implantation syndrome. A boy with tibial osteosarcoma experienced hypotension, tachyarrhythmia, desaturation, and hypocapnia following bone cement application during endoprosthetic surgery. Postoperatively, desaturation persisted. CT revealed a mural defect in the left pulmonary artery and segmental obstructions in multiple branches of both lungs, along with elevated D-dimer levels and echocardiographic evidence of increased right heart pressure. By postoperative day 20, oxygen saturation normalized (the patient was breathing ambient air). CT imaging showed resolution of the filling defect in the left pulmonary artery; however, signs of segmental pulmonary artery obstruction remained in the upper and middle lobes of the right lung and the lower lobe of the left lung. Thus, the hemodynamic catastrophe in the embolic phenotype of bone cement implantation syndrome represents a classic presentation of obstructive shock with subsequent thrombotic complications, driven by the combined mechanisms of microthrombogenesis and fibrinogenesis. The proposed pathogenetic phenotyping of bone cement implantation syndrome allows for a targeted approach to the prevention and treatment of hemodynamic and thrombotic complications in affected patients. This approach appears to be relevant and has the potential to reduce the incidence of adverse outcomes and complications.