Tunable VUV frequency comb for 229mTh nuclear spectroscopy.

Laser spectroscopy of the 229mTh nuclear clock transition is necessary for the future construction of a nuclear-based optical clock. Precision laser sources with broad spectral coverage in the vacuum ultraviolet are needed for this task. Here, we present a tunable vacuum-ultraviolet frequency comb based on cavity-enhanced seventh-harmonic generation. Its tunable spectrum covers the current uncertainty range of the 229mTh nuclear clock transition.

Validation of Clinical Criteria for Obtaining Maxillofacial Computed Tomography in Patients With Trauma.

BACKGROUND: More than 180,000 patients present annually with facial trauma to emergency rooms in the United States. Maxillofacial computed tomography is the gold standard in identifying facial fractures. Providers must evaluate patients quickly; therefore, they use decision instruments to determine which patients need imaging. We previously developed a decision instrument that identified patients with trauma at low risk for facial fracture who could avoid imaging. The present study aims to perform an internal validation of that tool. METHODS: The decision instrument used 5 criteria: bony step-off or instability, periorbital swelling or contusion, Glasgow Coma Scale <14, malocclusion, and tooth absence. The presence of any 1 finding placed the patient at high risk for fracture. In the present study, a retrospective review was conducted on all of the patients with trauma evaluated at a Level I trauma center for >1 year. Inclusion criteria were maxillofacial physical examination, head and maxillofacial computed tomography at presentation. Physical examination findings were collected and imaging reviewed to determine whether the decision tool could accurately detect the presence of a facial fracture in a different patient population from which it was derived. RESULTS: One hundred seventy-nine patients met enrollment criteria. Facial fractures occurred in 81% of patients (n = 145). The decision instrument was 97.4% sensitive (95% confidence interval, 93.8-99.3) for the presence of facial fracture. The negative predictive value was 81.3% (95% confidence interval, 55.0-95.0). Application of the instrument resulted in a missed injury rate of 2.6% (n = 3). All of the missed fractures were nondisplaced and managed nonoperatively. CONCLUSIONS: The proposed decision tool identifies patients with trauma at low risk for facial fracture who can avoid maxillofacial imaging. Validation in a prospective study is warranted.

Patterns of Facial Fractures and Protective Device Use in Motor Vehicle Collisions From 2007 to 2012.

IMPORTANCE: Facial fractures after motor vehicle collisions are a significant source of facial trauma in patients seen at trauma centers. With recent changes in use of seat belts and advances in airbag technology, new patterns in the incidence of facial fractures after motor vehicle collisions have yet to be quantified. OBJECTIVES: To evaluate the incidence of facial fractures and assess the influence of protective device use in motor vehicle collisions in patients treated at trauma centers in the United States. DESIGN, SETTING, AND PARTICIPANTS: Using a data set from the National Trauma Data Bank, we retrospectively assessed facial fractures in motor vehicle collisions occurring from 2007 through 2012, reported by level I, II, III, and IV trauma centers. Data analysis was performed from March 13 to September 22, 2015. MAIN OUTCOMES AND MEASURES: We characterized the data set by subsite of facial injury using International Classification of Diseases, Ninth Revision codes including mandible, midface, and nasal fractures. We assessed the influence of variables such as age, sex, race/ethnicity, crash occupant (driver or passenger), use of protective device, and presence or suspicion of alcohol use. RESULTS: A total of 518 106 patients required assessment at a trauma center after a motor vehicle collision, with 56 422 (10.9%) experiencing at least 1 facial fracture. Nasal fracture was the most common facial fracture (5.6%), followed by midface (3.8%), other (3.2%), orbital (2.6%), mandible (2.2%), and panfacial fractures (0.8%). Of the subset sustaining at least 1 facial fracture, 5.8% had airbag protection only, 26.9% used a seat belt only, and 9.3% used both protective devices, while 57.6% used no protective device. Compared with no protective device, the use of an airbag alone significantly reduced the likelihood of facial fracture after a motor vehicle collision (odds ratio, 0.82; 95% CI, 0.79-0.86); use of a seat belt alone had a greater effect (odds ratio, 0.57; 95% CI, 0.56-0.58) and use of both devices provided the greatest odds reduction (odds ratio, 0.47; 95% CI, 0.45-0.48). Younger age, male sex, and alcohol use significantly increased the likelihood of facial fracture. CONCLUSIONS AND RELEVANCE: For patients who presented to US trauma centers after motor vehicle collisions between 2007 and 2012, airbags, seat belts, and the combination of the 2 devices incrementally reduced the likelihood of facial fractures. LEVEL OF EVIDENCE: 3.

Clinical criteria for obtaining maxillofacial computed tomographic scans in trauma patients.

BACKGROUND: Over 150,000 patients present with maxillofacial trauma annually to emergency rooms in the United States. Although maxillofacial computed tomography is a sensitive screening tool for identifying facial fractures, indiscriminate use leads to unnecessary radiation exposure and substantial costs. A decision instrument is needed to ensure computed tomographic evaluation of patients at high risk for facial fracture and limit computed tomography use in low-risk patients. METHODS: A retrospective review was conducted of all patients evaluated at a Level I trauma center over a 3-year period. Inclusion criteria were maxillofacial examination on presentation, maxillofacial computed tomography, and head computed tomography. A total of 525 patients met the enrollment criteria. RESULTS: Injury to the maxillofacial skeleton occurred in 332 patients (63.2 percent). The presence of any of the following five physical examination criteria identified patients at high risk for facial fracture: bony stepoff or instability, periorbital swelling or contusion, Glasgow Coma Scale score less than 14, malocclusion, or tooth absence. These criteria identified all but six of the 332 patients with a facial fracture (sensitivity, 98.2 percent; 95 percent confidence interval, 96.5 to 99.1 percent). The negative predictive value was 87.8 percent (95 percent confidence interval, 76.3 to 94.2 percent). No patient determined by these criteria to be at low risk for a facial fracture required surgical treatment. If these criteria had been applied to the study population, radiographic imaging could have been avoided in 9.3 percent of patients. CONCLUSIONS: A decision instrument based on clinical criteria can ensure appropriate screening of patients at high risk for facial fracture. Application of this instrument may reduce unnecessary maxillofacial imaging.

Safety device use affects the incidence patterns of facial trauma in motor vehicle collisions: an analysis of the National Trauma Database from 2000 to 2004.

BACKGROUND: Airbags and seat belts are designed to decrease injuries sustained in motor vehicle collisions. The authors hypothesize that the use of these devices has an effect on the patterns of facial fractures and facial lacerations. METHODS: The records of 15,293 facial fracture patients and 114,623 facial laceration patients from motor vehicle collisions were analyzed from the National Trauma Database. Five hundred sixty-five patients were identified as having panfacial fractures. Fisher's exact test and chi-square analysis were used to study associations between safety devices and facial trauma. RESULTS: Panfacial fractures occurred in 3.7 percent of all patients sustaining facial fractures. In motor vehicle collisions resulting in facial fractures, 31.2 percent of patients had a seat belt, 5.6 percent had a seat belt and an airbag, 3.9 percent had an airbag only, and 59.3 percent had no safety device. The lack of a safety device in motor vehicle collisions increased the incidence of facial fractures (odds ratio, 2.26), panfacial fractures (odds ratio, 2.98), and facial lacerations (odds ratio, 1.95). Passengers with facial fractures were more likely to have not used a safety device (odds ratio, 1.69). CONCLUSIONS: Based on the largest reported series on motor vehicle collision-associated facial fractures in the United States, the use of airbags and seat belts is associated with a significantly decreased incidence of facial fractures and lacerations. Given that fewer than half of these patients used a safety device and the high morbidity and costs associated with these injuries, plastic surgeons should advocate for the increased use of these safety devices.

Management of mandible fractures.

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Review the incidence and etiology of mandible fractures. 2. Discuss indications and techniques for closed and open treatment of mandible fractures. 3. Review complications of mandible fractures. BACKGROUND: Mandible fractures are among the most common types of facial fractures treated by plastic surgeons. They must be managed carefully to maintain the function of the mandible, reestablish proper occlusion, and minimize secondary complications. METHODS: Current methods of management include combinations of soft diet, intermaxillary fixation, open reduction with plate fixation, and, rarely, external fixation. RESULTS: Decision-making depends on the age of the patient, type of fracture identified, and concomitant medical conditions or injuries. CONCLUSION: The authors review the diagnosis and current trends in management of mandible fractures.