Innovative workflow combining desktop 3D printing and surgical navigation in acral tumors

Surgical navigation techniques have shown potential benefits in orthopedic oncology surgery. However, acral tumor resections do not benefit from image guided surgery (IGS). Our study proposed the use of a desktop 3D printer to produce patientspecific molds for resembling the distal extremity position depicted in preoperative images and during IGS, and to produce specific attachments for tracking certain surgical tools. The navigation system is compounded of a multi-camera optical tracking system and an open-source navigation software (3D Slicer). A new specific module “PatientNavigation” was  added to 3D Slicer platform for acral tumor navigation. The feasibility of the workflow proposed was evaluated with two clinical cases (soft-tissue sarcomas in a hand and a foot). A commercial pointer and an electric scalpel were used to point out a tissue in the patient’s anatomy. The 3D printing and the  sterilization processes do not lead to important deformations of the mold (mean error of 1.5 mm). The IGS testing over the 3D printed models achieved a mean result of 1.8 mm. None problem occurred during the IGS with the real patients that led to abort navigation and the surgeons were satisfied with the  navigation results. Therefore, the workflow proposed is feasible to be used in real patients for acral tumors resection and it could be adapted to other surgical scenarios.