Bone Tissue Engineering (BTE) of the Craniofacial Skeleton, Part II: Translational Potential of 3D-Printed Scaffolds for Defect Repair.

Computer-aided design/computer-aided manufacturing and 3-dimensional (3D) printing techniques have revolutionized the approach to bone tissue engineering for the repair of craniomaxillofacial skeletal defects. Ample research has been performed to gain a fundamental understanding of the optimal 3D-printed scaffold design and composition to facilitate appropriate bone formation and healing. Benchtop and preclinical, small animal model testing of 3D-printed bioactive ceramic scaffolds augmented with pharmacological/biological agents have yielded promising results given their potential combined osteogenic and osteoinductive capacity. However, other factors must be evaluated before newly developed constructs may be considered analogous alternatives to the "gold standard" autologous graft for defect repair. More specifically, the 3D-printed bioactive ceramic scaffold's long-term safety profile, biocompatibility, and resorption kinetics must be studied. The ultimate goal is to successfully regenerate bone that is comparable in volume, density, histologic composition, and mechanical strength to that of native bone. In vivo studies of these newly developed bone tissue engineering in translational animal models continue to make strides toward addressing regulatory and clinically relevant topics. These include the use of skeletally immature animal models to address the challenges posed by craniomaxillofacial defect repair in pediatric patients. This manuscript reviews the most recent preclinical animal studies seeking to assess 3D-printed ceramic scaffolds for improved repair of critical-sized craniofacial bony defects.

The Revolving Door of Residency: Predictors of Residency Attrition for Urology Matriculants Between 2001 and 2016.

OBJECTIVE: To add to the literature which has reported higher attrition rates amongst General Surgery residents who identify as female or underrepresented in medicine (URM), we aimed to determine how these factors contribute to attrition within Urology. We hypothesized that women and URM Urology residents will similarly have higher attrition rates. METHODS: The Association of American Medical Colleges surveyed residents to obtain matriculation and attrition status from 2001 to 2016. Data included demographics, medical school type, and specialty. A multivariable logistic regression model was performed to identify predictors of attrition amongst Urology residents. RESULTS: In our sample of 4321 Urology residents, 22.5% were female, 9.9% were URM, 25.8% were older than 30 years, 2.5% were Doctor of Osteopathic Medicine graduates and 4.7% were International Medical Graduates. On multivariable analysis, being female (Odds ratio [OR] = 2.3, P < .001) was associated with increased residency attrition when compared to male residents. Additionally, residents who matriculated between 30 and 39 years old (OR = 1.9, P < .001) or ≥40 years old (OR = 10.7, P < .001) had an increased risk of residency attrition when compared to residents who matriculated between 26 and 29 years old. Attrition rates for URM trainees have recently increased. CONCLUSION: Women, older, and URM Urology residents experience higher rates of attrition compared to their peers. It is essential to identify trainees with a higher likelihood of attrition to determine system-level changes to combat departures from training programs. Our study highlights the need to foster more inclusive training environments and change institutional cultures to diversify the surgical workforce.

Engineering 3D Printed Bioceramic Scaffolds to Reconstruct Critical-Sized Calvaria Defects in a Skeletally Immature Pig Model.

BACKGROUND: Three-dimensional printed bioceramic scaffolds composed of 100% ß-tricalcium phosphate augmented with dipyridamole (3DPBC-DIPY) can regenerate bone across critically sized defects in skeletally mature and immature animal models. Before human application, safe and effective bone formation should be demonstrated in a large translational animal model. This study evaluated the ability of 3DPBC-DIPY scaffolds to restore critically sized calvarial defects in a skeletally immature, growing minipig. METHODS: Unilateral calvarial defects (~1.4 cm) were created in 6-week-old Göttingen minipigs ( n = 12). Four defects were filled with a 1000 µm 3DPBC-DIPY scaffold with a cap (a solid barrier on the ectocortical side of the scaffold to prevent soft-tissue infiltration), four defects were filled with a 1000 µm 3DPBC-DIPY scaffold without a cap, and four defects served as negative controls (no scaffold). Animals were euthanized 12 weeks postoperatively. Calvariae were subjected to micro-computed tomography, 3D reconstruction with volumetric analysis, qualitative histologic analysis, and nanoindentation. RESULTS: Scaffold-induced bone growth was statistically greater than in negative controls ( P ≤ 0.001), and the scaffolds with caps produced significantly more bone generation compared with the scaffolds without caps ( P ≤ 0.001). Histologic analysis revealed woven and lamellar bone with haversian canals throughout the regenerated bone. Cranial sutures were observed to be patent, and there was no evidence of ectopic bone formation or excess inflammatory response. Reduced elastic modulus and hardness of scaffold-regenerated bone were found to be statistically equivalent to native bone ( P = 0.148 for reduced elastic modulus of scaffolds with and without caps and P = 0.228 and P = 0.902 for hardness of scaffolds with and without caps, respectively). CONCLUSION: 3DPBC-DIPY scaffolds have the capacity to regenerate bone across critically sized calvarial defects in a skeletally immature translational pig model. CLINICAL RELEVANCE STATEMENT: This study assessed the bone generative capacity of 3D-printed bioceramic scaffolds composed of 100% ß-tricalcium phosphate and augmented with dipyridamole placed within critical-sized calvarial defects in a growing porcine model.

The Nasoalveolar Molding Cleft Protocol: Long-Term Treatment Outcomes from Birth to Facial Maturity.

BACKGROUND: The authors present outcomes analysis of the nasoalveolar molding treatment protocol in patients with a cleft followed from birth to facial maturity. METHODS: A single-institution retrospective review was conducted of cleft patients who underwent nasoalveolar molding between 1990 and 2000. Collected data included surgical and orthodontic outcomes and incidence of gingivoperiosteoplasty, alveolar bone grafting, surgery for velopharyngeal insufficiency, palatal fistula repair, orthognathic surgery, nose and/or lip revision, and facial growth. RESULTS: One hundred seven patients met inclusion criteria (69 with unilateral and 38 with bilateral cleft lip and palate). Eighty-five percent (91 of 107) underwent gingivoperiosteoplasty (unilateral: 78 percent, 54 of 69; bilateral: 97 percent, 37 of 38). Of those patients, 57 percent (52 of 91) did not require alveolar bone grafting (unilateral: 59 percent, 32 of 54; bilateral: 54 percent, 20 of 37). Twelve percent (13 of 107) of all study patients underwent revision surgery to the lip and/or nose before facial maturity (unilateral: 9 percent, six of 69; bilateral: 18 percent, seven of 38). Nineteen percent (20 of 107) did not require a revision surgery, alveolar bone grafting, or orthognathic surgery (unilateral: 20 percent, 14 of 69; bilateral: 16 percent, six of 38). Cephalometric analysis was performed on all patients with unilateral cleft lip and palate. No significant statistical difference was found in maxillary position or facial proportion. Average age at last follow-up was 20 years (range, 15 years 4 months to 26 years 10 months). CONCLUSIONS: Nasoalveolar molding demonstrates a low rate of soft-tissue revision and alveolar bone grafting, and a low number of total operations per patient from birth to facial maturity. Facial growth analysis at facial maturity in patients who underwent gingivoperiosteoplasty and nasoalveolar molding suggests that this proposal may not hinder midface growth. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Plastic Surgery Innovation with 3D Printing for Craniomaxillofacial Operations.

Plastic Surgery restores unique human qualities such as appearance, speech (palate), hands, to improve interaction with others and quality of life. Three-dimensional printing technology can be applied to Plastic Surgery craniomaxillofacial operations to change the bony skeleton of the skull, face, and jaws. Three-dimensional printing for patient-specific applications have four types: Type I contour models, Type II guides, Type III splints, Type IV implants. Plastic Surgery innovation in 3D printing clinical applications are described here and https://www.slucare.edu/newsroom/kmov-science-of-healing-faces-of-childhood.php.

Pilot and Passenger Injuries Associated with Powered Parachutes.

BACKGROUND: Powered parachutes are becoming a popular form of sport flying. No previous study has reviewed injuries in this sport. The purpose of this study was to describe the injuries associated with powered parachute flying, the flight factors involved in an incident, and the impact an incident has on current sport involvement. METHODS: National Transportation Safety Board incident reports involving powered parachutes between 2004 and 2015 were reviewed. Internet searches were performed to contact involved pilots to find further information. RESULTS: There were 71 incidents reported involving 117 people. Of these, 10 incidents involved 14 fatalities (12.0%). Of the 14 fatalities, 11 (78.5%) occurred in midflight. Pilot error was the most common finding for an incident and accounted for 53/71 incidents (74.6%). The main error was misjudging the distance required for takeoff and landing. This accounted for 37/71 incidents (52.1%). Orthopedic extremity injuries were the most common severe injuries reported. Surgical intervention was needed in 43.8% of injuries and 48.0% of those involved fractures. The median return to work was 14 d (range 0-180 d). Only 4/53 (7.5%) of the pilots contacted continued to fly powered parachutes. DISCUSSION: Powered parachute participants are at risk for unique injuries compared to other forms of flight. A powered parachute injury can have a significant impact on future pilot involvement in the sport. This study provides evidence for design changes in the aircraft and helps direct pilot training. This information can improve the safety and well-being of participants so they can continue to fly powered parachutes. Skelley NW, Yarholar LM, Richardson LC. Pilot and passenger injuries associated with powered parachutes. Aerosp Med Hum Perform. 2016; 87(11):947-953.