Epidemiology of maxillofacial fractures in northwest China: an 11-year retrospective study of 2240 patients.

BACKGROUND: The aim of this study was to determine the epidemiological pattern of maxillofacial fractures in northwestern China by retrospectively analysing the demographics, aetiologies, concomitant injuries, fracture sites, and management. METHODS: A 10-year retrospective analysis of 2240 patients with maxillofacial fractures admitted to the General Hospital of Ningxia Medical University was conducted. The extracted data included sex, age, aetiology, fracture site, concomitant injuries, time of treatment, therapeutic approaches and complications. Statistical analyses were performed, including descriptive analysis and the chi-square test. Logistic regression was used to determine the impact factors of maxillofacial fractures and concomitant injuries. P values < 0.05 were considered statistically significant. RESULTS: The age of the included patients ranged from 1 to 85 years, and the mean age was 35.88 ± 15.69 years. The male-to-female ratio was 3.9:1. The most frequent aetiology of maxillofacial fractures was road traffic accidents (RTAs) (56.3%), and the most common fracture sites were the anterior wall of the maxillary sinus, arcus zygomaticus and mandibular body. A total of 1147 patients (51.2%) were affected by concomitant injuries, with craniocerebral injury being the most common. Logistic regression analyses revealed increased risks of mid-facial fractures in elderly individuals (odds ratio (OR) = 1.029, P < 0.001) and females (OR = 0.719, P = 0.005). Younger patients had a higher risk of mandibular fractures (OR = 0.973, P < 0.001). RTAs increased the risk for mid-facial fractures and high falls increased the risk for mandibular fractures. CONCLUSIONS: The maxillofacial fracture pattern is correlated with sex, age and aetiology. Patients were mainly young and middle-aged males, and the main cause of injury was RTAs, mostly causing compound fractures. Medical staff must be systematically educated to comprehensively examine patients with injuries resulting from RTAs. The management of patients with fractures requires thorough consideration of the patient's age, aetiology, fracture site, and concomitant injuries.

Hybrid system with stable structure of hard/soft tissue substitutes induces re-osseointegration in a rat model of biofilm-mediated peri-implantitis.

Re-osseointegration of an infected/contaminated dental implant poses major clinical challenges. We tested the hypothesis that the application of an antibiotic-releasing construct, combined with hard/soft tissue replacement, increases the efficacy of reconstructive therapy. We initially fabricated semi-flexible hybrid constructs of ß-TCP/PHBHHx, with tetracycline (TC) (TC amounts: 5%, 10%, and 15%). Thereafter, using in vitro assays, TC release profile, attachment to rat bone marrow-derived stem cells (rBMSCs) and their viability as well as anti-bacterial activity were determined. Thereafter, regenerative efficacies of the three hybrid constructs were assessed in a rat model of peri-implantitis induced by Aggregatibacter actinomycetemcomitans biofilm; control animals received ß-TCP/Bio-Gide and TC injection. Eight weeks later, maxillae were obtained for radiological, histological, and histomorphometric analyses of peri-implant tissues. Sulcus bleeding index was chronologically recorded. Serum cytokines levels of IL-6 and IL-1ß were also evaluated by enzyme-linked immunosorbent assay. Substantial amounts of tetracycline, from hybrid constructs, were released for 2 weeks. The medium containing the released tetracycline did not affect the adhesion or viability of rBMSCs; however, it inhibited the proliferation of A. actinomycetemcomitans. Osteogenesis and osseointegration were more marked for the 15% hybrid construct group than the other two groups. The height of attachment and infiltration of inflammatory cells within fibrous tissue was significantly reduced in the experimental groups than the control group. Our protocol resulted in re-osseointegration on a biofilm-contaminated implant. Thus, an antibiotic releasing inorganic/organic construct may offer a therapeutic option to suppress infection and promote guided tissue regeneration thereby serving as an integrated multi-layer substitute for both hard/soft tissues.

Optimizing carbon efficiency of jet fuel range alkanes from cellulose co-fed with polyethylene via catalytically combined processes.

Enhanced carbon yields of renewable alkanes for jet fuels were obtained through the catalytic microwave-induced co-pyrolysis and hydrogenation process. The well-promoted ZSM-5 catalyst had high selectivity toward C8-C16 aromatic hydrocarbons. The raw organics with improved carbon yield (∼44%) were more principally lumped in the jet fuel range at the catalytic temperature of 375°C with the LDPE to cellulose (representing waste plastics to lignocellulose) mass ratio of 0.75. It was also observed that the four species of raw organics from the catalytic microwave co-pyrolysis were almost completely converted into saturated hydrocarbons; the hydrogenation process was conducted in the n-heptane medium by using home-made Raney Ni catalyst under a low-severity condition. The overall carbon yield (with regards to co-reactants of cellulose and LDPE) of hydrogenated organics that mostly match jet fuels was sustainably enhanced to above 39%. Meanwhile, ∼90% selectivity toward jet fuel range alkanes was attained.

Expected treatment dose construction and adaptive inverse planning optimization: implementation for offline head and neck cancer adaptive radiotherapy.

PURPOSE: To construct expected treatment dose for adaptive inverse planning optimization, and evaluate it on head and neck (h&n) cancer adaptive treatment modification. METHODS: Adaptive inverse planning engine was developed and integrated in our in-house adaptive treatment control system. The adaptive inverse planning engine includes an expected treatment dose constructed using the daily cone beam (CB) CT images in its objective and constrains. Feasibility of the adaptive inverse planning optimization was evaluated retrospectively using daily CBCT images obtained from the image guided IMRT treatment of 19 h&n cancer patients. Adaptive treatment modification strategies with respect to the time and the number of adaptive inverse planning optimization during the treatment course were evaluated using the cumulative treatment dose in organs of interest constructed using all daily CBCT images. RESULTS: Expected treatment dose was constructed to include both the delivered dose, to date, and the estimated dose for the remaining treatment during the adaptive treatment course. It was used in treatment evaluation, as well as in constructing the objective and constraints for adaptive inverse planning optimization. The optimization engine is feasible to perform planning optimization based on preassigned treatment modification schedule. Compared to the conventional IMRT, the adaptive treatment for h&n cancer illustrated clear dose-volume improvement for all critical normal organs. The dose-volume reductions of right and left parotid glands, spine cord, brain stem and mandible were (17 ± 6)%, (14 ± 6)%, (11 ± 6)%, (12 ± 8)%, and (5 ± 3)% respectively with the single adaptive modification performed after the second treatment week; (24 ± 6)%, (22 ± 8)%, (21 ± 5)%, (19 ± 8)%, and (10 ± 6)% with three weekly modifications; and (28 ± 5)%, (25 ± 9)%, (26 ± 5)%, (24 ± 8)%, and (15 ± 9)% with five weekly modifications. CONCLUSIONS: Adaptive treatment modification can be implemented including the expected treatment dose in the adaptive inverse planning optimization. The retrospective evaluation results demonstrate that utilizing the weekly adaptive inverse planning optimization, the dose distribution of h&n cancer treatment can be largely improved.

Adaptive replanning strategies accounting for shrinkage in head and neck IMRT.

PURPOSE: Significant anatomic and volumetric changes occur in head and neck cancer patients during fractionated radiotherapy, and the actual dose can be considerably different from the original plan. The purposes of this study were (1) to evaluate the differences between planned and delivered dose, (2) to investigate margins required for anatomic changes, and (3) to find optimal replanning strategies. METHODS AND MATERIALS: Eleven patients, each with one planning and six weekly helical CTs, were included. Intensity-modulated radiotherapy plans were generated using the simultaneous integrated boost technique. Weekly CTs were rigidly registered to planning CT before deformable registration was performed. The following replanning strategies were investigated with different margins (0, 3, 5 mm): midcourse (one replan), every other week (two replans), and every week (six replans). Doses were accumulated on the planning CT for comparison of various dose indices for target and critical structures. RESULTS: The cumulative doses to targets were preserved even at the 0-mm margin. Doses to cord, brainstem, and mandible were unchanged. Significant increases in parotid doses were observed. Margin reduction from 5 to 0 mm led to a 22% improvement in parotid mean dose. Parotid sparing could be preserved with replanning. More frequent replanning led to better preservation; replanning more than once a week is unnecessary. CONCLUSION: Shrinkage does not result in significant dosimetric difference in targets and critical structures, except for the parotid gland, for which the mean dose increases by approximately 10%. The benefit of replanning is improved sparing of the parotid. The combination of replanning and reduced margins can provide up to a 30% difference in parotid dose.