Suchyta, Marissa A

AbstractAdvances in computer-aided design and computer-aided manufacturing software have improved translational applications of virtual surgical planning (VSP) in craniomaxillofacial surgery, allowing for precise and accurate fabrication of cutting guides, stereolithographic models, and custom implants. High-resolution computed tomography (CT) imaging has traditionally been the gold standard imaging modality for VSP in craniomaxillofacial surgery but delivers ionizing radiation. Black bone magnetic resonance imaging (MRI) reduces the risks related to radiation exposure and has comparable functionality when compared with CT for VSP. Our group has studied the accuracy of utilizing black bone MRI in planning and executing several types of craniofacial surgeries, including cranial vault remodeling, maxillary advancement, and mandibular reconstruction using fibular bone. Here, we review clinical applications of black bone MRI pertaining to VSP and three-dimensional (3D)-printed guide creation for craniomaxillofacial surgery. Herein, we review the existing literature and our institutional experience comparing black bone MRI and CT in VSP-generated 3D model creation in cadaveric craniofacial surgeries including cranial vault reconstruction, maxillary advancement, and mandibular reconstruction with fibular free flap. Cadaver studies have demonstrated the ability to perform VSP and execute the procedure based on black bone MRI data and achieve outcomes similar to CT when performed for cranial vault reshaping, maxillary advancement, and mandibular reconstruction with free fibula. Limitations of the technology include increased time and costs of the MRI compared with CT and the possible need for general anesthesia or sedation in the pediatric population. VSP and 3D surgical guide creation can be performed using black bone MRI with comparable accuracy to high-resolution CT scans in a wide variety of craniofacial reconstructions. Successful segmentation, VSP, and 3D printing of accurate guides from black bone MRI demonstrate potential to change the preoperative planning standard of care. Black bone MRI also reduces exposure to ionizing radiation, which is of particular concern for the pediatric population or patients undergoing multiple scans.

Summary: Advances in virtual surgical planning and three-dimensionally–printed guides have enabled increased precision in vascularized free fibula flap reconstruction of the mandible and valuable preoperative planning. However, virtual surgical planning currently requires high-resolution computed tomographic scans, exposing patients to ionizing radiation. The aim of this study was to determine whether black bone magnetic resonance imaging can be used for accurate surgical planning and three-dimensionally–printed guide creation, thus reducing patient radiation exposure. This study included 10 cadaver heads and 10 cadaver lower extremities. A mock fibula free flap for mandible reconstruction was performed. Five operations were planned with guides created using black bone magnetic resonance imaging, whereas the other five were planned and performed using guides created with computed tomographic scan data. All specimens underwent a postoperative computed tomographic scan, and three-dimensional reconstruction of scans was performed and surgical accuracy to the planned surgery was assessed. Guides created from black bone magnetic resonance imaging demonstrated high accuracy to the surgical plan. There was no statistically significant difference in postoperative deviation from the plan when black bone magnetic resonance imaging versus computed tomographic scanning was used for virtual surgical planning and guide creation. Both modalities led to a postoperative positive or negative deviation from the virtual plan within 0.8 mm. This study demonstrates that virtual surgical planning and three-dimensionally–printed guide creation for free fibula flaps for mandible reconstruction can be performed using black bone magnetic resonance imaging with comparable accuracy to computed tomographic scanning. This could reduce radiation exposure for patients and enable a more streamlined imaging process for head and neck cancer patients.

Background: Face transplantation can offer functional and aesthetic restoration to patients who have exhausted their reconstructive options, improving quality of life and psychosocial integration. Ethical issues in face transplantation abound, including questions of patient selection and evaluation before transplantation. To date, there has been no study of ethicists’ opinions regarding face transplantation. Methods: An online survey of attendees of the 2015 International Conference on Clinical Ethics Consultation (n = 401) assessed ethicists’ opinions about face transplantation. Questions examined the risk-to-benefit ratio of immunosuppression; permissibility of face transplantation in subpopulations (including children and blind patients); donor-recipient age, sex, and ethnicity mismatches; and ethical oversight. Results: Most ethicists (84 percent) agreed that it is permissible to perform a face transplantation on an adult in the absence of clear medical contraindications. Most respondents also agreed that it is permissible to perform a face transplantation on a child (62 percent) or a blind patient (61 percent), yet demonstrated less consensus regarding the permissibility of performing a face transplantation on patients with an increased risk of immune rejection. Respondents were generally supportive of age, sex, and ethnicity mismatches, with 43 percent indicating that it is permissible to have a sex mismatch. The majority answered that face transplantation should be covered by federal insurance (74 percent). Conclusions: This study provides insight into clinical ethicists’ views regarding face transplantation. Most ethicists support the ethical permissibility of face transplantation, and did not have concerns about age, sex, and ethnicity mismatches. These findings highlight emerging areas of consensus regarding the ethical permissibility of face transplantation.

Background: Various vascular pedicles have been used to supply the proximal fibula for vascularized epiphyseal transfer. The optimal pedicle has, however, not been agreed on. This study aimed to describe the detailed vascular anatomy of the proximal fibula to assist the surgeon in choosing the optimal pedicle. Methods: Twenty-eight lower extremities were injected with latex or a mixture of latex and barium sulfate. Vessels supplying the proximal fibula were identified and dissected, and the course, diameter, anatomical relations, length, and branches were documented. In the barium group, high-resolution computed tomographic scanning was conducted before dissection. In seven specimens, branches of the deep peroneal nerve to the tibialis anterior muscle were carefully preserved, and their relation to the proximal fibular vascularity was noted. Results: An anastomotic vascular network supplied the proximal fibula. This was formed superiorly by branches of the inferior lateral genicular artery, and inferiorly by branches of the anterior tibial artery, the most important of which were the first and second recurrent epiphyseal arteries. One or more deep peroneal nerve branches passed deep to the first recurrent epiphyseal artery in all specimens examined. In five specimens, all of the branches were superficial to the second recurrent epiphyseal artery, whereas two had branches deep to it. Conclusions: The proximal fibula can be transferred using the inferior lateral genicular or anterior tibial artery because of the existing anastomosis. Factors including length of pedicle, potential for nerve injury, and diaphyseal portion to be harvested should be considered in the pedicle choice.

The purpose of this study was to evaluate the time to diagnosis and management of hook of hamate fractures in an era of advanced imaging. We performed a retrospective study of 51 patients treated for hook of hamate fractures. Patients were sent a quickDASH questionnaire regarding the outcomes of their treatment. Hook of hamate fractures were diagnosed with advanced imaging at a median of 27 days. Clinical findings of hook of hamate tenderness had better sensitivity than carpal tunnel-view radiographs. Nonunion occurred in 24% of patients with non-operative treatment and did not occur in the operative group. Both treatment groups achieved good clinical results, with a grip strength of 80% compared with the non-injured hand and a median quickDASH score of 2. Advanced imaging improved the time to diagnosis and treatment compared to historical case series. Nonunion is common in patients treated non-operatively. Level of evidence: IV