Point of Care Virtual Surgical Planning and Three-Dimensional Printing for Feminizing Foreheadplasty.

Abstract

Facial feminization surgery provides significant and tangible benefits for improved quality of life and psychosocial health for transgender women.1,2 One of the most significant determinants of gender is the frontonasal-orbital complex, as elucidated from anatomic studies of skulls by Douglas Ousterhout in 1987.3,4 Subsequently, he published a classification scheme relating the thickness of the anterior table and size of the frontal sinus with surgical techniques designed to feminize foreheads. The male forehead has increased supraorbital bossing, an enlarged frontal sinus, flat lower-set brows, deeper orbits, an M-shaped hairline, and a flattened forehead compared to the average female forehead.5 Depending on the thickness of the anterior table of the frontal sinus, contouring can be achieved with minimal bony reduction with a burr for type I forehead. For type II forehead, bony reduction and augmentation of the recessed area above the sinus with alloplastic materials are needed (historically, methylmethacrylate was used,6 but newer materials have been reported). Type III forehead is the most common and often requires a frontal sinus osteotomy, recontouring of the bone, and bony setback to achieve an optimal result. Surgeons using these techniques have reported minimal complications and high satisfaction rates.7–11 Preoperative computed tomography scanning and three-dimensional reconstruction before facial feminization delineate skeletal and sinus anatomy and can also be useful tools in patient consultation. Virtual surgical planning has become an invaluable tool in craniomaxillofacial surgery applications to improve outcomes and to reduce operative time.12 Three-dimensional reconstructions are then performed using computer-aided design or computer-aided modeling software environments. [See Figure, Supplemental Digital Content 1, which shows the three-dimensional computed tomographic scan of the patient’s bony forehead and cutting guide (manufactured at point of care) for anterior table setback, https://links.lww.com/PRS/E720.] During preoperative planning, reformatted images from the computed tomography scan can be used to generate a three-dimensionally printed skeletal model. (See Figure, Supplemental Digital Content 2, which demonstrates that the three-dimensionally printed model of the patient’s bony forehead with the cutting guide can be manufactured at the point of care with inexpensive resins. This allows for mock surgery to be performed ahead of the scheduled surgery if needed, https://links.lww.com/PRS/E721.) Point-of-care virtual planning and three-dimensional printing allow the surgeon to work closely with the bioengineers to finalize the virtual plan. Point-of-care prefabrication of cutting guides and three-dimensionally printed models improve the efficiency of this process. Point-of-care three-dimensionally printed guides and models may be used for “mock surgery” if needed before the scheduled surgery, as in orthognathic surgical planning. [See Video (online), which demonstrates a mock surgery of the three-dimensionally printed model using the cutting guide.] Virtual surgical planning–generated colored maps allow for safe and precise burring or osteotomy of the frontal bone and allow less intraoperative contouring before repositioning and fixation of the anterior table. (See Figure, Supplemental Digital Content 3, which shows the three-dimensional computed tomographic scan of the bony forehead showing bony thickness in a colored map. The cutting guides and the color map allow the surgeon to plan areas of osteotomy and additional contouring safely, https://links.lww.com/PRS/E722.) {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Video.","caption":"This video shows mock surgery of the three-dimensionally printed model using the cutting guide. (Used with permission of Mayo Foundation for Medical Education and Research, all rights reserved.)","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_4y9d7p0g"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]} Most frequently, an anterior hairline incision is made with extension toward the temporal hairline, with limited subperiosteal dissection into the superior orbit. The flap is elevated in a subperiosteal plane to the frontonasal suture line and to the zygomaticofrontal suture lines bilaterally. Care is taken to preserve the supraorbital neurovascular bundle. Burring of the supraorbital rims and forehead is performed according to the virtual plan to achieve the desired forehead contour. The prefabricated cutting guide is positioned over the frontal sinus. (See Figure, Supplemental Digital Content 4, which shows intraoperative use of the point-of-care manufactured cutting guide for forehead feminizing surgery, https://links.lww.com/PRS/E723.) Next, a precise frontal sinus osteotomy is performed around the cutting guide borders using a drill with a stop, and the osteotomy is completed using an osteotome. The anterior table can be contoured with a burr until it recesses into the preplanned osteotomy created in the frontal sinus and then fixated with low-profile titanium plates and screws or wires. The supraorbital bar is further contoured to achieve feminizing features according to the virtual plan. The soft-tissue response to bony reduction must be taken into account for the final aesthetic result. It is important to note that the upper third of the face is also an area with ethnic variation. The forehead flap is advanced according to the plan if a brow lift is needed and the anterior hairline can be lowered. Before any approach to forehead contouring is undertaken, assessment of the frontal sinus dimensions and bony thickness is essential. Preoperative computed tomographic imaging is necessary to assess frontal sinus anatomy, septa, and anterior table thickness. Risks of forehead contouring should be discussed with the patient and can include bone resorption, malunion or nonunion of bones, alopecia, asymmetry, infection, mucocele formation, and potential need for reoperation. Finally, other facial feminization procedures can be achieved during this surgery, including blepharoplasties, fat grafting, rhinoplasty midface, and mandibular contouring if needed. Point-of-care virtual surgical planning permits the surgeon to attempt multiple approaches in a virtual environment, thereby optimizing surgical planning and allowing revision of the plan before the operation.13 These three-dimensionally printed models are invaluable during consultation to educate patients and review the surgical plans. We found these three-dimensionally printed models to provide an enhanced medium for patient consultation and informed consent discussion. Furthermore, these models help in surgical education of trainees, who can participate in the mock surgery before the planned procedure. At our institution, we use point-of-care virtual surgical planning to generate patient-specific cutting guides, templates, and, soon, patient-specific implants. Figure, Supplemental Digital Content 4: Intra-operative use of point of care manufactured cutting guide for forehead feminizing surgery. DISCLOSURE None of the authors has financial disclosures to report.