Guided Frontal Sinus Osteotomy: A Pilot Study of a Digital Protocol for “In-House” Manufacturing Surgical Cutting Guides

<b>Objective:</b> Frontal sinus surgery is still challenging for surgeons; the frontal osteotomy with the preparation of a frontal bone flap to access the sinus is usually hand-crafted by experienced surgeons. The objective of our study is to present a fully digital protocol for the manufacturing of "in-house" surgical cutting guides, customized to the patient's anatomy, to perform precise frontal sinus osteotomy, showing the costs, times, and intraoperative complications reduction. <b>Materials and Methods:</b> A prospective study was conducted on 12 patients with complex pathologies involving the frontal sinus who underwent frontal sinus osteotomy in the Maxillofacial Surgery Unit of the Federico II University of Naples, from January 2021 to April 2025, considering the last surgery in November 2023. The same digital protocol to manufacture the surgical cutting guide was used for all the 12 patients. The first step was to upload the preoperative CT images in DICOM format to the software Mimics Medical to perform a rapid segmentation of the skull region of interest to create a 3D object and to identify the frontal sinus margins and the osteotomy lines. The second step was to realize the surgical cutting guide, incorporating the design of titanium plates to fix onto the skull in order to make a precise osteotomy. The final digital step was to export the cutting guide 3D object in the software "Formlab-Form 3B" to print the model with a specific resin. The model was then used during the surgery to perform the precise frontal osteotomy by piezo surgery. The clinical outcomes, in terms of complications and recurrences, were then recorded. <b>Results:</b> In all the patients, no intraoperative complications occurred; the median follow-up was 31.7 months and at one year of follow-up only one patient experienced a recurrence. The mean operative time was about 4 h, with a frontal osteotomy time of about 23 min. Digital protocol time was about 4 h while printing times were between 2 and 4 h. <b>Conclusions:</b> This "in-house" protocol seems to demonstrate that the use of intraoperative templates for the realization of the frontal sinus osteotomy reduces preoperative and intraoperative costs and times, reducing the risk of intraoperative complications, and also allows less experienced surgeons to perform the procedure safely. Obviously, this study is to be considered a "pilot study", and other studies with large cohorts of patients will have to confirm these promising results.