Do Regional Nerve Blocks During Bimaxillary Surgery Decrease Postoperative Pain and Vomiting Compared With Patient-Controlled Analgesia?

BACKGROUND: Postoperative pain after orthognathic surgery is commonly managed with opioids, which can cause nausea and vomiting. PURPOSE: The purpose of this study was to determine whether regional nerve blocks during bimaxillary surgery reduced postoperative pain and vomiting compared with patient-controlled analgesia (PCA). STUDY DESIGN, SETTING, AND SAMPLE: This retrospective cohort study recruited patients who underwent bimaxillary surgery between August 2018 and September 2020 at the Fourth Military Medical University Hospital. Participants whose procedures involved the cheekbone, temporomandibular joint, mandibular angle, or an autogenous iliac bone graft and those who were admitted to the intensive care unit after surgery were excluded. PREDICTOR VARIABLES: The primary predictor variables were postoperative analgesia management, regional maxillary and inferior alveolar nerve blocks, and PCA. OUTCOME VARIABLES: The primary outcome variables were moderate-to-severe postoperative pain and postoperative vomiting (POV) during the first 24 hours. Moderate-to-severe pain was defined as pain numerical rating scale ≥4, POV was defined as vomiting of gastrointestinal contents. COVARIATES: The study covariates included demographic, surgical, and anesthesia characteristics. ANALYSES: Statistical analyses were conducted using an unpaired t-test, χ2 test, or Fisher's exact test for the bivariate analysis. A multivariate logistic regression analysis was performed to assess the associations between the primary predictor variables and outcomes. Statistical significance was set at P < .05. RESULTS: 354 participants were included in the study (262 in the nerve block group, mean age 22.5 ± 4.0 years; 92 in the PCA group, mean age 22.6 ± 4.4 years; P = .81). There was no significant difference in sex between the groups (63.4 and 55.4% females in nerve block and PCA groups, respectively, P = .18). The multivariate regression analyses demonstrated that nerve blocks did not decrease moderate-to-severe postoperative pain (7.6 vs 10.9%, adjusted odds ratio = 0.67, 95% confidence interval: 0.22-2.01, P = .48), although they were associated with decreased POV (38.5 vs 65.2%, adjusted odds ratio = 0.34, 95% confidence interval: 0.18-0.65, P = .001). CONCLUSION AND RELEVANCE: For bimaxillary surgery, regional nerve blocks as opioid-free postoperative analgesia were not significantly associated with decreased postoperative pain but were associated with a lower POV risk.

Novel GNAI3 mutation in a Chinese family with auriculocondylar syndrome and treatment of severe dentofacial deformities: a 5-year follow-up case report.

BACKGROUND: Auriculocondylar syndrome (ARCND) is an extremely rare autosomal dominant or recessive condition that typically manifests as question mark ears (QMEs), mandibular condyle hypoplasia, and micrognathia. Severe dental and maxillofacial malformations present considerable challenges in patients' lives and clinical treatment. Currently, only a few ARCND cases have been reported worldwide, but most of them are related to genetic mutations, clinical symptoms, and ear correction; there are few reports concerning the treatment of dentofacial deformities. CASE PRESENTATION: Here, we report a rare case of ARCND in a Chinese family. A novel insertional mutation in the guanine nucleotide-binding protein alpha-inhibiting activity polypeptide 3 (GNAI3) was identified in the patient and their brother using whole-exome sequencing. After a multidisciplinary consultation and examination, sequential orthodontic treatment and craniofacial surgery, including distraction osteogenesis and orthognathic surgery, were performed using three-dimensional (3D) digital technology to treat the patient's dentofacial deformity. A good prognosis was achieved at the 5-year follow-up, and the patient returned to normal life. CONCLUSIONS: ARCND is a monogenic and rare condition that can be diagnosed based on its clinical triad of core features. Molecular diagnosis plays a crucial role in the diagnosis of patients with inconspicuous clinical features. We present a novel insertion variation in GNAI3, which was identified in exon 2 of chromosome 110116384 in a Chinese family. Sequential therapy with preoperative orthodontic treatment combined with distraction osteogenesis and orthognathic surgery guided by 3D digital technology may be a practical and effective method for treating ARCND.

A macrophage plasma membrane-coated and DNA structured nanomedicine targets to alleviate rheumatoid arthritis via dual inhibition to TNF-α and NF-κB.

High heterogenicity of rheumatoid arthritis (RA) leads to poor response in many patients. Combined therapies that simultaneously inhibit multiple proinflammatory targets may improve anti-RA efficacy. However, which monotherapies to combine and how to achieve the combination are critical issues. Here, we design a macrophage plasma membrane-coated and DNA structured nanomedicine to achieve a dual inhibitory therapy to Tumor necrosis factor alpha (TNF-α) and NF-κB. An anti-NF-κB decoy oligodeoxynucleotides (dODN) is first conjugated to a DNA cage with precise numbers and locations (Cage-dODN). Meanwhile, an anti-TNF-α siRNA is anchored to extracted macrophage plasma membrane (siRNA@M). Subsequently, siRNA@M is used to encapsulate Cage-dODN to fabricate siRNA@M(Cage-dODN) (siMCO). The size and zeta potential of siMCO are 63.1 ± 15.7 nm and -20.7 ± 3.8 mV respectively. siMCO shows increased intracellular uptake by inflamed macrophages and enhanced accumulation in inflamed mouse paws. siMCO also reduces pro-inflammatory factors at genetic and protein levels, alleviates arthritic symptoms, and shows no influence to major blood components. These results show that siMCO is a potential targeted, efficient, and safe dual inhibitory therapy for the treatment of inflammatory arthritis. The macrophage plasma membrane can be utilized to improve the targeting, stability, and efficacy of DNA structured nanomedicines.

Comparison of clinical effects of two surgical approaches in the treatment of acetabular fractures.

Objective: To determine the clinical effect of lateral rectus abdominis approach and modified Stoppa approach for the surgical treatment of acetabular fractures. Methods: A retrospective analysis was performed on the case data of 30 patients with acetabular fractures admitted to the Department of Orthopaedics of Hengshui City People's Hospital from June 2017 to June 2021. According to the surgical methods, the enrolled patients were divided into the lateral rectus abdominis approach group (observation group) and the modified Stoppa approach group (control group), with 15 patients in each group. Further comparison was made on the incision length, operation time, intraoperative blood loss, length of stay in the hospital, fracture reduction, hip joint function, neurological recovery, and postoperative complications between the two groups. Results: There was no significant difference between the two groups in the length of stay in the hospital, hip joint function score, fracture reduction quality, and excellent-to-good rate of hip joint function (p>0.05). There were significant differences in incision length, intraoperative blood loss, operation time, postoperative motor and touch function scores, and postoperative complication rate between the observation group and the control group (p<0.05). Conclusion: The clinical effect of the lateral rectus abdominis approach is close to that of the modified Stoppa approach for the surgical treatment of acetabular fracture patients. However, and importantly, surgery through the lateral rectus abdominis approach has less trauma, shorter operation time, lower surgical complications, and good postoperative functional recovery.

Facial changes in patients with skeletal class III deformity after bimaxillary surgery: an evaluation based on three-dimensional photographs registered with computed tomography.

The objective of this study was to evaluate facial soft and hard tissue changes, individually and relative to each other, in patients with skeletal class III deformity after bimaxillary surgery using three-dimensional (3D) photos obtained by white light scanning. Thirty patients with skeletal class III deformity who underwent bimaxillary surgery were selected. Each patient underwent white light scanning and spiral computed tomography (CT) within two weeks before (T0) and six months after surgery (T1). The 3D photos were registered with CT soft tissue models for T0 and T1, and the skeletal area unaffected by treatment (cranial base) was used to register T0 and T1. Then, the 3D colour-coded map was analysed to assess both skeletal and soft tissue changes between T0 and T1. Changes in the 3D coordinates of each anatomical landmark were analysed using the Student's t-test. Maxillary advancement by 2-3 mm and mandibular recession by 5-6 mm were observed; the mandible was shortened in the vertical direction. Compared with the preoperative values, the nasal columella was 0.51 mm shorter, the upper lip was 0.71 mm longer, the base of the alar cartilage was 1.38 mm wider, and the nasolabial angle became larger. The ratio of change in the position of soft tissue point Sn to hard tissue point A was 0.73:1, and that of soft tissue point Pg to hard tissue point Pog was 0.86:1. Images obtained by structured white light scanning registered with CT can be used as an alternative to study facial changes after orthognathic surgery.

Self-Assembling Anchorage of Hyaluronic Acid on the Nanoparticle Surface Confers Superiority of Triple Negative Breast Cancer Treatment.

Triple-negative breast cancer (TNBC) has been listed as one of the most fatal diseases, and no effective targeting treatment is clinically available. Although CD44-targeting hyaluronic acid (HA) has been utilized as targeting ligands in many studies, no facile ways have been developed through HA self-assembly at the nanoparticle surface. Herein, we reported N-isopropylacrylamide-grafted chitosan-based nanoparticles self-assembling with HA (HA-NPs) through electrostatic forces and loaded with curcumin (CUR). The HA-NPs displayed pH-responsive properties due to the chemical modification of chitosan, and the preparation process was optimized by central composite design-response surface methodology. HA anchorage confers the vehicle with tumor-targeting capability. HA-NPs displayed more robust effects of inhibiting TNBC primary tumor growth than free CUR and a plain counterpart but without increased systemic cytotoxicity. In addition, in vivo pharmacokinetic studies showed that HA-NPs significantly increased the in vivo residence time of free CUR and improved the bioavailability of CUR. These findings suggested that chitosan-based HA-NPs may provide a feasible and unique strategy to achieve CD44 targeting and enhance its efficacy in vivo for the treatment of advanced TNBC.

Effects of probiotics on nonalcoholic fatty liver disease: a systematic review and meta-analysis.

OBJECTIVES: Several studies have suggested that the gut-liver axis is closely related to nonalcoholic fatty liver disease (NAFLD). This study was designed to conduct a meta-analysis based on a randomized controlled trial (RCT) to systematically evaluate the efficacy of probiotics in the treatment of NAFLD. METHODS: This study carried out a literature search of published scientific data (up to April 2021) on probiotic therapies of NAFLD. The quality of the included literature was evaluated, and the corresponding data were extracted using the RevMan5.4 software. RESULTS: A total of 9 randomized clinical trials involving 352 patients with NAFLD were included in this study. Results of the meta-analysisstudy showed that probiotic therapy group have significant reduction in the levels of serum indices: alanine aminotransferase (ALT), aspartate transaminase (AST) and total cholesterol (TC) in comparison with the control group. Probiotic therapy was not associated with changes in body mass index (BMI) homeostasis model assessment of insulin resistance (HOMA-IR) and tumor necrosis factor (TNF) Subgroup analyses of BMI indicated that three or more composite probiotics or probiotic treatment for more than three months can significantly reduce the BMI level. CONCLUSION: This systematic review and meta-analysis demonstrated that modulating gut microbiota may be utilized as an effective method to improve liver function and reduce blood lipid levels in patients with NAFLD.

Experimental Study on the Bone Morphogenetic Protein 1-Modified Bone Marrow Mesenchymal Stem Cell Sheets to Promote Mandibular Distraction Osteogenesis.

OBJECTIVE: The present study aims to increase the concentration of genetically modified bone marrow mesenchymal stem cells (BMSCs) in the distraction osteogenesis (DO) interstitial space and induce the conversion of BMSCs to osteoblasts to improve the osteogenic efficiency in DO and shorten the treatment period. METHODS: Bone morphogenetic protein 1 (BMP-1) and green fluorescent protein (GFP) gene-modified cell sheets of BMSCs were constructed by tissue engineering. Thirty-six New Zealand white rabbits were randomly divided into three groups: group A (the blank control group), group B (the GFP group) with the injection of GFP gene-modified BMSC sheets into the DO gap, and group C (the BMP-1 group) with the injection of BMP-1 gene-modified BMSC sheets into the DO gap. Rabbits in all three groups were distracted for 5 days at a distraction rate of 2.0 mm/d, once/day. After distraction, the above-mentioned cell sheet suspension was injected into the distraction gap to observe osteogenesis, which was observed by gross specimen observation, micro-computed tomography (Micro-CT) scanning, and histomorphology. RESULTS: The gross specimen observation showed that all animals had smooth and continuous bone cortex in the distraction region with relatively high hardness. The osteogenesis quality or hardness was ranked from the highest to the lowest, as Group C > Group B > Group A. Micro-CT and histomorphological observation revealed that group C had better maturation and bone volume of the new bone in the DO region at weeks 3 and 6 than groups B and A. CONCLUSION: BMP-1 gene-modified BMSC sheets could effectively promote the formation of new bone during rapid DO in the mandible, compensating for the poor osteogenesis caused by rapid distraction and providing a new approach to shorten the DO treatment period in clinical practice.

Overexpression of Bone Morphogenetic Protein-1 Promotes Osteogenesis of Bone Marrow Mesenchymal Stem Cells In Vitro.

BACKGROUND Osteogenesis of bone marrow mesenchymal stem cells (BMSCs) is an important research topic in the application of bone tissue engineering. Bone morphogenetic protein-1 (BMP-1) is important in bone formation and stability, but its effects on the osteogenesis of BMSCs are unclear. This study aimed to investigate the association of BMP-1 with the osteogenic capacity of BMSCs. MATERIAL AND METHODS Primary rabbit BMSCs were cultured and divided into a BMP-1-overexpressing group, a Green Fluorescent Protein-expressing (GFP) group, and a Control group. The transfection efficiency of BMP-1 was tested by Western blotting. Cell viabilities, alkaline phosphatase (ALP) activities, Ca2+ concentrations, and gross examinations of BMSC sheets were examined at different times. The osteogenic marker collagen I was assessed by immunohistochemical analysis. RESULTS The cell viability, ALP activity, and Ca2+ content of the BMP1-overexpressed group were significantly enhanced compared with the GFP group and Control group. Immunohistochemistry staining results showed that BMP-1 promoted the expression of type I collagen in BMSCs sheets. CONCLUSIONS Our results suggest that the overexpression of BMP-1 can promote the osteogenesis of BMSCs and provides an improved method of cell-based tissue engineering.

Risk of Colorectal Cancer in Ulcerative Colitis Patients: A Systematic Review and Meta-Analysis.

BACKGROUND: Ulcerative colitis (UC) patients have an increased risk for the development of colorectal cancer (CRC). Our aim was to assess the risk of CRC in UC patients compared with disease extent, disease duration, and geographic variation. METHODS: In this systematic review and meta-analysis, we searched PubMed, scientific meetings, and the bibliographies of identified articles, with English language restrictions for studies published from 1988 to 2018, and assessed the risk of CRC in UC patients. Patients with Crohn's disease, family history of CRC, and colorectal adenomatous polyp (CAP) were excluded from this research. The study was registered with PROSPERO, number CRD42018102213. FINDINGS: We included 58 studies that included 267566 UC patients. Extensive UC and left-sided UC had a higher risk of CRC than proctitis UC. Geography also played a role in UC-associated CRC development. The time of malignant transformation in Asian UC patients started after 10-20 years of this disease duration. North American UC-associated CRC patients significantly increased in more than 30 years of this disease duration. CONCLUSION: In a systematic review of the literature, we found that disease extent, disease duration, and geography were strong, independent risk factors in UC-associated CRC development.

Exposure and risk assessment of volatile organic compounds and airborne phthalates in Singapore's Child Care Centers.

Infants and children under 6 years old spend most of daily time in Child Care Centers (CCCs), especially in the tropical regions like Singapore. Environmental exposure and associated risk during this early critical developmental stage is of great public concern. In this study, seven representative volatile organic compounds (VOCs) and five typical phthalates were analyzed in the indoor and outdoor air samples collected from 32 Singapore CCCs. The median of total VOC and phthalate concentration in indoor air was 19.03 and 5.41 µg m-3; respectively. For both indoors and outdoors environment, benzene, toluene and xylene were the dominant VOC contributors (more than 68%). For indoor air phthalates, di(2-ethylhexyl) phthalate and di-butyl phthalate (DBP) accounts for 60-76%. The level of both VOCs and phthalates in indoor environment was significantly higher than that in outdoor, with an average indoor/outdoor ratio of 1.24 and 1.45; respectively. A strong correlation (r > 0.50, p < 0.05) was observed between indoor and outdoor air compounds. VOC and phthalate levels have no significant difference between CCCs with split-unit and centrally ventilated air conditioners. Monte Carlo simulation was used to estimate exposure uncertainty and variability for the risk assessment. Overall, the concentrations of VOC were below the healthy reference values from either EPA Integrated Risk Information System (IRIS) or Singapore guideline. However, similar to other countries' report, benzene, DBP, ethylbenzene and naphthalene were at levels that could exceed the stringent standards such as Office of Environmental Health Hazard Assessment (OEHHA) cancer and reproductive health-based benchmarks.

[Three-dimensional study of facial soft tissue changes in patients with skeletal Class â ¢ malocclusion before and after orthognathic surgery].

Objective: To investigate the changes of facial soft tissue before and after orthognathic surgery in patients with skeletal Class Ⅲ malocclusion. Methods: Between August 2016 and April 2017, 30 patients with skeletal Class Ⅲ malocclusion who underwent maxillary LeFort Ⅰ osteotomy and sagittal split mandible osteotomy were selected as study subjects. Among them, 11 were male and 19 were female with an average age of 22.6 years (range, 18-35 years). Full head CT scan and facial soft tissue three-dimensional image scan were performed within 2 weeks before surgery and at 6 months after surgery. A three-dimensional facial image model was established using Artec Studio 11.0 and CMF Proplan 3.0 software to analyze the facial soft tissue changes before and after surgery. The soft tissue anatomical landmarks in each area of the face were measured and compared before and after surgery. Results: The area of facial soft tissue change after surgery was the maxillary nose and the lower jaw area, and the two sides did not exceed the vertical boundary of the outer canthus. After surgery, the horizontal points of bilateral alar bases and bilateral cheeks changed significantly ( P<0.05). The sagittal points of subnasale, pronasale, bilateral alar bases, upper lip margin significantly forwarded ( P<0.05); the sagittal points of the bilateral cheilions, lower lip margin, midpoint of chin-lip groove, pogonion, and menton significantly backwarded ( P<0.05). The vertical points of the upper lip margin, bilateral cheilions, lower lip margin, bilateral cheeks, and bilateral inner canthus points significantly descended ( P<0.05), and the vertical point of the menton significantly elevated ( P<0.05). After surgery, the nasal column was significantly shortened, the upper lip got longer and the alar base widened when compared with those before surgery ( P<0.05). Conclusion: The overall change of face after double jaw surgery is shorter and fuller, and the mandible of facial soft tissue change is larger than that of maxillary, which suggests that the postoperative facial changes should be taken into account in the surgical design.

Assessing the Quality of Life in Patients With Dentofacial Deformities Before and After Orthognathic Surgery.

PURPOSE: This study aimed to assess the effect of health-related quality of life (QoL) among patients with dentofacial deformities who underwent orthognathic surgery compared with a control group without dentofacial deformities by use of generic oral health and condition-specific approaches. PATIENTS AND METHODS: In this prospective study, 2 questionnaires were administered to 85 patients (31 male and 54 female patients) who were evaluated before undergoing orthognathic surgery. The Short Form Oral Health Impact Profile Questionnaire (OHIP-14) and the Orthognathic Quality of Life Questionnaire (OQLQ) were administered before and 5 to 7 months after orthognathic surgery. The control group comprised 96 young university student volunteers without dentofacial deformities. RESULTS: The questionnaires were collected 5 to 7 months after surgery. The preoperative scores of the patients and the control group were contrasted separately. The respondents' postoperative OHIP-14 and OQLQ scores were significantly lower (P < .001 for total scores). The preoperative OQLQ scores for all domains were significantly higher among the patients than among the controls (P < .001 for total scores), whereas the total scores and 3 subscale scores of the OHIP-14 in the functional and psychological domains were significantly higher among the patients than among the controls (P < .05 for total scores). The preoperative and postoperative OQLQ total scores were remarkably different between male and female patients (P < .05). The postoperative OQLQ total scores were considerably higher in older patients than in younger patients (P < .05). All patients in the Class III group who underwent double-jaw surgery showed remarkable changes after surgery (P < .001 for total scores). CONCLUSIONS: Patients with dentofacial deformities had a poorer QoL compared with the healthy population, especially in functional and psychological aspects. Orthognathic surgery had a significant positive impact on QoL. Patients with Class III malocclusion who underwent double-jaw surgery seemingly benefitted the most after surgery.

Biomechanical analysis of a curvilinear distractor device for correcting mandibular symphyseal defects.

PURPOSE: The local mechanical environment is a determinant of successful transport disc distraction osteogenesis. This study assessed the biomechanics of a curvilinear distractor device for correcting mandibular symphyseal defects. MATERIALS AND METHODS: The finite element method was used to analyze an intact mandible, mandibular distractor bodies with different rail thicknesses (4, 6, 8, and 10 mm), and mandibular distractor bodies with rails and auxiliary lingual brackets. RESULTS: Rail thickness was positively correlated with maximum von Mises stress in the distractor and negatively correlated with maximum displacement of the mandibular distractor bodies. The maximum von Mises stress occurred at the junction of the rails and fixed arms. It also exceeded the yield strength of the titanium material. Compared with the maximum displacement of the intact mandible, that of the mandibular distractor bodies was visibly increased. CONCLUSION: An auxiliary lingual bracket can effectively decrease stress in such devices and displacement of mandibular distractor bodies. Rail fixation alone cannot achieve stability for distraction osteogenesis. Using an auxiliary lingual bracket effectively prevents distractor breakage and exposure.

Assessment on the occupational exposure of manufacturing workers to Dechlorane Plus through blood and hair analysis.

Dechlorane Plus (DP), as a widely used flame retardant in different electrical and textile applications, has recently attracted great concern around the world. The present study investigated the DP levels and distribution in human samples from a DP manufacturing plant and a nearby area in east China. The DP concentrations ranged from 89.8 to 2958 ng/g lipid weight in whole blood and 4.08 to 2159 ng/g dry weight in hair. For the workers engaged in DP manufacturing process, their DP levels were significantly higher than those in most of the other two control groups from the nearby area. The values of anti-DP fractional abundance (fanti ratio) were commonly lower in the human samples from both the manufacturing plant and nearby area compared with those in the commercial products, and excretion as well as biotransformation are possible reasons for stereoselective accumulation of the syn-DP isomer in humans. Furthermore, a significantly positive relationship (p < 0.05) was obtained between (i) the concentrations (and fanti) in the paired blood and hair samples, indicating a similar distribution pattern of the two DP isomers in the paired samples; (ii) the DP levels in human body and the exposure time (p < 0.05), which suggests that further assessment could be needed to investigate potential long-term risks to the occupational population.

Treatment of malignant triton tumor in zygomatic region.

Malignant triton tumor (MTT) is extremely rare and supposed to be highly aggressive because of high propensity for local recurrence and metastasis. To date, only about 170 cases were reported in various body locations including trunks, maxillary sinus, neck, extremities, retroperitoneal, and so on. We present a case of MTT in the zygoma with good outcome. A 27-year-old male patient with progressive swelling and pain in the right zygoma was proved to have an MTT by biopsy. Radical resection accompanying postoperative radiotherapy was adopted, and then the soft and hard tissue defects were repaired by prosthesis. The patient recovered well and was satisfied with the facial contour. At 45-month follow-up, there was no recurrence or metastasis that occurred. According to literature review, one third of MTTs appeared in the head and neck regions and seem to have a better prognosis. Radical resection is the most important remedy, and adjuvant radiotherapy could be helpful. With early finding and effective treatments, satisfactory outcome could be achieved.

Myofibroblasts and their resistance to apoptosis: a possible mechanism of osteoradionecrosis.

Osteoradionecrosis (ORN) in the head and neck area is the most devastating long-term complication of radiotherapy, with slow progression and inability to heal spontaneously. ORN can lead to intolerable pain, fractures, and sequestration of devitalized bone and fistulae, making oral feeding impossible and causing facial deformation. In spite of its notorious reputation over at least 90 years, the precise pathogenesis of ORN has not been fully clarified, which has led to obstacles in the management of the disease. Several theories about its pathogenesis have been formulated, and radiation-induced fibrosis is the newest one. According to this theory, ORN is essentially a type of fibrosis induced by radiotherapy, and antifibrosis therapy has been shown to be effective in its treatment. We assumed that ORN, like fibrosis in other organs, is the result of a process of fibrogenesis in which myofibroblasts are the key effector cells. The uninterrupted accumulation of myofibroblasts and consequent persistent excess production of collagenous extracellular matrix and tensile force result in loss of normal function and ultimately radiation-induced fibrosis. During this process, myofibroblasts may be protected from apoptosis by acquiring an immune-privileged capacity, which allows continuous matrix synthesis. If this hypothesis proves to be correct, it would enable better understanding of the cellular and molecular mechanisms underlying the pathogenesis and progression of ORN, and would help improve our ability to prevent occurrence of ORN, give an earlier diagnosis, and treat it more effectively.

Modified internal mandibular distraction osteogenesis in the treatment of micrognathia secondary to temporomandibular joint ankylosis: 4-year follow-up of a case.

Micrognathia and obstructive sleep apnoea syndrome (OSAS) are problems subsequent to temporomandibular joint ankylosis (TMJa) in growing patients. For patients with micrognathia and OSAS secondary to TMJa, it is important to restore proper mandibular form and dimension, achieve occlusal stability and recover satisfactory joint movement. We report a 4-year follow-up of a patient with micrognathia and OSAS secondary to bilateral TMJa. The treatment of this patient involved (1) a modified internal mandibular distraction osteogenesis without altering the pre-existing occlusion; (2) TMJ arthroplasty in which the dislocated disc was found and repositioned and the shape of the glenoid fossa and articular head was formed without removing bone in vertical dimension; (3) passive mouth-opening exercise with an individualized occlusal pad postoperatively for one month; and (4) orthodontic treatment for the occlusal disturbance and active mouth-opening exercise for one year. After the treatment the micrognathia was corrected; the oropharyngeal airway was increased significantly; mouth-opening increased to 40mm intraoperatively was maintained at 36.66mm 4 years after surgery. Satisfactory occlusion was achieved after orthodontic treatment. Through the 4-year follow-up, no signs of reankylosis were found. In conclusion, this new clinical protocol is a safe, effective and quick way to treat micrognathia and OSAS secondary to TMJa.

Use of a new curvilinear distractor to repair mandibular defects in dogs.

We have investigated the feasibility of using a new curvilinear distractor to repair mandibular defects in 6 mature male dogs. A mandibular defect was created by an oblique osteotomy between the distal planes of the bilateral second premolars, and a transport disc 10mm wide was made. After a 7-day latency period, distraction was activated at 0.5mm/12h and consolidation lasted for 6 or 12 weeks. Three dogs were killed after 6 and 12 weeks' consolidation for gross, radiographic, and histological observations to be made. Curvilinear distraction osteogenesis was successful in 5/6 animals. At both time points smooth curved bone had been restored in the distracted areas, and radiographic and histological examination showed that the generated bone was similar to normal bone after 12 weeks' consolidation. These results suggest that the curvilinear distractor could complete curvilinear distraction osteogenesis in dogs' mandibles.