Computerized Three-Dimensional Analysis: A Novel Method to Assess the Effect of Open-Door Laminoplasty

Introduction: The three-dimensional elaboration of morphological data derived from computed tomography (CT) and magnetic resonance imaging (MRI) scans generates virtual anatomical reconstructions. Here, we propose a novel protocol to analyze the postoperative results of open-door laminoplasty to evaluate differences in the volume of the spinal canal. The protocol uses geometric models in patients with cervical degenerative myelopathy before versus after cervical laminoplasty. Materials and methods: Mimics and 3-Matic software (Materialise, Leuven, BE) programs were used to segment anatomical structures and create polygon meshes of spines. Patients with cervical spondylotic myelopathy were enrolled. The models obtained before and after laminoplasty were superimposed by using a global registration function. The magnitude of divergence was quantified by using the root-mean-square error (RMSE). Results: Using this novel protocol, we were able to map the differences in the volume of the spinal canal before laminoplasty and after laminoplasty and to quantify its magnitude and calculate the volumes. Discussion and conclusions: The development of a procedure to measure the space within the cervical bone walls using geometric parameters represents a new, powerful method to verify the results obtained by cervical laminoplasty. Further research horizons may include the routine use of virtual models in surgical planning for this procedure.