ObjectiveTo study the application of threedimensional (3D) printing technique in the surgical resection of sinonasal malignancies and postoperative defect repair.MethodsClinicopathological data of 10 patients suffering from sinonasal malignant tumors surgically treated in our department from Jan. 2015 to June 2017 were analyzed retrospectively. The sinonasal malignant tumors included squamous carcinoma (n=4), osteosarcoma (n=1), olfactory neuroblastoma (n=2), adenoid cystic carcinoma (n=2), and mucoepidermoid carcinoma (n=1). Before operation, all patients received computerized tomography (CT) scan of nasosinus. 3D images of the affected sinuses were reconstructed, and their 3D models were established and printed. On the 3D models, preoperative design and simulated operation were performed to confirm the resection range as well as the area needs to be repaired. Proper surgical approaches were adopted to implement tumor resection with simultaneous defect repair. All patients were given postoperative radiotherapy and followed up closely. The surgical accuracy and function recovery were evaluated with postoperative CT scan and functional examinations.ResultsOn the basis of 3D preoperative design, tumor resection was successfully achieved in all 10 cases. Of them, simultaneous defect repair was performed in 8 patients, including defect repair of maxilla and/orbital wall with preformed titanium mesh in 6 and repair of skull base bone defect with nasal septal mucoperiosteal flap in 2. All patients got cured without serious complications. During operation, the position relationships among the tumor and surrounding anatomical structures were defined, complete tumor resection and accurate localization as well as repair of defect were accomplished. Postoperative CT scan showed consistencies of resection range, defect site and reconstructed configuration with those in the preoperative design. All the patients had been followed up for 12 to 30 months, and recurrence occurred in none.ConclusionWith advantages of being able to implement preoperative design, simulated operation and postoperative prediction, 3D printing technique is feasible and reliable for the surgical treatment of sinonasal malignancies, which may facilitate confirmation of resection range and defect repair, and therefor improve the surgical accuracy and therapeutic effect.