Automated 3D Analysis of Zygomaticomaxillary Fracture Rotation and Displacement.

BACKGROUND: The zygomaticomaxillary complex (ZMC) can experience a multitude of deforming forces. There is limited understanding on which deformities alter patient outcomes. This study utilized an automated, three-dimensional analysis to elucidate which fracture patterns and rotational deformities are most prevalent and associated with postoperative complications. METHODS: This study was a 7-year retrospective review of patients with unilateral ZMC fractures who underwent surgical intervention. Patient demographics, injury mechanisms, presenting symptoms, and postoperative outcomes were collected. Segmentation was completed using Mimics software. The lateral-medial, superior-inferior, and anterior-posterior axes were manually identified on the zygoma and then displacement, rotational direction, and rotational degrees were automatically calculated using Geomagic software. Total displacement score was generated by summation of individual displacement scores at each of the five sutures. RESULTS: Eighty-one patients satisfied inclusion criteria. The most prevalent rotational pattern of the zygoma was medially-superiorly-posteriorly (P < 0.001). When comparing rotation along the three axes, the zygoma had the greatest rotation along the lateral-medial axis compared with the superior-inferior (P = 0.003) and anterior-posterior (P < 0.001) axes. Within each axis, the zygoma was more likely to rotate medially than laterally (P = 0.003) and posteriorly than anteriorly (P = 0.01). Multivariate analysis identified total displacement scores and degrees rotated along the lateral-medial axis as significant predictors of facial complications and reoperation. CONCLUSIONS: This study suggests that patients with unilateral ZMC fractures who undergo surgical intervention are at an increased risk for adverse outcomes with greater rotation along the lateral-medial axis and higher total displacement scores. Additionally, the automated analysis method described can provide objective data to better characterize ZMC fractures.

Utilizing 3D-Printed Orbital Floor Stamps to Create Patient-Specific Implants for Orbital Floor Reconstruction.

PURPOSE: This study seeks to test a novel technique of custom-printed midface contour models with orbital floor "stamps" to guide reconstruction of orbital floor blowout fractures, with or without concomitant zygomaticomaxillary complex injury. METHODS: A series of 4 consecutive patients with orbital floor blowout fractures (including 3 with zygomatic maxillary complex fractures) were retrospectively examined for outcomes associated with orbital floor reconstruction using 3-dimensional-printed stamps and midface models. Data collected included demographics, pre- and postoperative visual globe malposition, motility, and visual field disturbances. Three-dimensional printing methodology is reported, as well as associated costs and time required to generate the models and stamps. RESULTS: The cost of producing a midface-contour model and orbital floor stamps was $131, inclusive of labor and materials. Cases averaged 170 minutes to segment, design, and print. Patients with preoperative diplopia and motility restrictions had resolution of their symptoms. Two patients had resolution of their enophthalmos, while one patient with a concomitant zygomaticomaxillary fracture had persistent mild enophthalmos. CONCLUSIONS: Midface contour models and orbital floor stamps may be produced in a timely and cost-effective manner. Use of these "homemade" stamps allows for patient-specific custom-contoured orbital floor reconstruction. Further studies are warranted to examine long-term visual and esthetic outcomes for these patients.

Cost Analysis for In-house versus Industry-printed Skull Models for Acute Midfacial Fractures.

Industry-printed (IP) 3-dimensional (3D) models are commonly used for secondary midfacial reconstructive cases but not for acute cases due to their high cost and long turnaround time. We have begun using in-house (IH) printed models for complex unilateral midface trauma. We hypothesized that IH models would decrease cost and turnaround time, compared with IP models. METHODS: We retrospectively examined cost and turnaround time data from midface trauma cases performed in 2017-2019 using 3D models (total, n = 15; IH, n = 10; IP, n = 5). Data for IH models were obtained through itemized cost reports from our Biomedical Engineering Department, where the models were printed. Data associated with IP models were obtained through itemized cost reports from our industry vendor. Perioperative data were collected from electronic medical records. RESULTS: The average cost for IH models ($236.38 ± 26.17) was significantly less (P < 0.001) than that for IP models ($1677.82 ± 488.43). Minimal possible time from planning to model delivery was determined. IH models could be produced in as little as 4.65 hours, whereas the IP models required a minimum of 5 days (120 hours) from order placement. There were no significant differences in average operating room time (P = 0.34), surgical complications, or subjective outcomes, but there was a significant difference in estimated blood loss (P = 0.04). CONCLUSION: Utilization of IH 3D skull models is a creative and practical adjunct to complex unilateral midfacial trauma that also reduces cost and turnaround time compared with IP 3D models.

Simple and Rapid Creation of Customized 3-dimensional Printed Bolus Using iPhone X True Depth Camera.

PURPOSE: Three-dimensional printing has produced customized bolus during radiation therapy for superficial tumors along irregular skin surfaces. In comparison, traditional bolus materials are often difficult to manipulate for a proper fit. Current 3-dimensional printed boluses are made from either preexisting computed tomography scans or complex surface scanning methods. Herein, we introduce an inexpensive, convenient approach to generate a 3-dimensional printed bolus from surface scanning technology available in common smartphones. METHODS AND MATERIALS: A three-dimensional printed bolus was designed using surface scans from iPhone X true depth cameras and a low-cost 3-dimensional printer. The percentage density infill was adjusted to achieve tissue equivalence. To evaluate the clinical feasibility, fit against the skin surface and radiation dose distribution were compared with those of the traditional bolus. RESULTS: We fabricated a customized 3-dimensional printed bolus for different areas of the face using an iPhone X camera and inexpensive commercially available 3-dimensional printer. When printed at 100% density, the bolus material approximated soft tissue/water and provided an equivalent dose distribution to that found with standard bolus materials on direct comparison. The bolus material is inexpensive and produces an ideal fit with the scanned anatomy. CONCLUSIONS: We present a simplified method of highly customized bolus production that requires minimal experience with computer modeling programs and can be accomplished with an iPhone true depth camera.