Construction of a three-dimensional skull model using spiral computer tomography data / 中国组织工程研究

BACKGROUND: A three-dimensional spiral computer tomography can display stereoscopic pictures with multi angles on films or computer screens. However, it is hard to display complex three-dimensional anatomical morphology on two-dimensional films or computer screens. Thus, three-dimensional models are needed in craniomaxillofacial surgery simulation or conceptual design.OBJECTIVE: To establish a three-dimensional skull model using spiral computer tomography data and to explore its application in craniofacial surgery.METHODS: Skull of the patient was scanned with Picker 6000 spiral computer tomography with 2.0 slice thickness and 1.0 pitch,and the obtained data were treated in Voxel Q image workstation for three-dimensional reconstruction with volume rendering technique. After having been downloaded to personal computer at 0.1 mm interval, the transaxial two-dimensional image data were converted into two-dimensional digitized contour data by using image processing software developed by the experimental team. The wire frame and solid images of craniofacial triangular facets could be reconstructed when the digitized data were inputted into image processing software of Surfacer 9.0.RESULTS AND CONCLUSION: The three-dimensional wire frame and solid image of skull was reconstructed and computer aided design for plastic operation was accomplished on it. Then the simulacrum of underlay was obtained by rapid prototyping technology. A three-dimensional skull model could be established using spiral computer tomography data. It might play an important role in the diagnosis and treatment of tumors, injuries and abnormality in craniofacial surgery.

Computer-assisted design and rapid prototyping technology for the underlay of hemifacial atrophy / 中国组织工程研究

BACKGROUND: There are many methods for repairing the hemifacial atrophy, the most common is preparing plaster facial mold of the patient, with wax piled on the surface to restore the patient's facial shape, and wax pattern serves as a reference of surgical pad. However, the therapeutic effect for the correction and treatment is not satisfactory due to varied abnormality and difficult plans.OBJECTIVE: To discuss the feasibility of manufacturing underlay for the treatment of hemifacial atrophy using computer-assisted design and rapid prototyping technology. METHODS: Skull of the hemifacial atrophy patient was scanned with Picker 6000 SCT, and the data obtained were processed in Voxel Q image workstation for 3-D reconstruction with volume rendering technique. After the interval lamination, the images were downloaded at 0.4-mm interval in a BMP format using CuteFTP 4.0 software. Then the transaxial 2-D image data were converted into digitized 2-D contour data by using image processing software developed by experimental team through a series of processes, including filtering, screening, noise reduction, and distortion correction. The edges and contour of the images was extracted to obtain a vector diagram of facial cranial cortical bone contour line. The digitized data were inputted into image processing software of Surfacer 9.0 for vector superposing, thus the 3-D wire frame and solid images of skull could be reconstructed. According to mirror-image symmetry relation, the point-cloud data of facial bone on the normal side was duplicated to the atrophied side. Thus a 3-D model of the underlay was produced between the atrophied bone and the mirror image of normal side. In order to compensate the atrophy of soft tissues, the model was designed 1.5 mm thicker. After the three-dimensional Surfacer data on the CAD were re-stratified, the contour editing of the underlay and the supporting set of prototype were completed in RpDataRepare, forming RP files and creating underlay template through rapidly output of the processing file for rapid prototyping required, as a reference of surgical procedures.RESULTS AND CONCLUSION: The 3-D solid model of the patient skull bone surface contour was obtained and simulacrum of the underlay was prepared with computer assistance and rapid prototyping. According to the simulacrum, the operation was carried out and got a satisfactory result. The manufacture of underlay for the treatment of hemifacial atrophy could be accomplished by computer assisted design and rapid prototyping in a highly precise and rapid manner. It is a promising technique in the field of individualized underlay making in craniofacial surgery.

Establishment of an animal model of blast-fragment combine injury on facial nerve / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study was to establish an animal model to imitate facial nerves injury by explosion.</p><p><b>METHODS</b>The impact was simulated by detonator blast in the distance of 5 cm, 10 cm and 15 cm over the face of dogs under anesthesia and the edge injury of masseters were made by rifle-shot steel ball to imitate segment injury in real explosion. The dogs were killed after different time of injury and the heart, lung, brain and facial nerve were taken to observe the pathological changes in order to evaluating the wound effect in different distances.</p><p><b>RESULTS</b>The animal was injured severely in the distance of 5 cm and could not survive for a long time because of severe damage to brain, heart and lung. The dogs injured at 10 cm could survive after emergency treatment, and there was diffusing hemorrhage in edematous nerve trunk. In the distance of 15 cm, the dogs were injured slightly and, as the distance to the explosive source increased, the local wound became slighter. Under light microscope, the breakage and necrosis of facial nerve fibers could be widely observed, degenerative and necrotic neurons with infiltrating inflammatory cells could be found in the facial nerve nuclei as well.</p><p><b>CONCLUSION</b>The dog's traumatic model established by impact wave and segment in this experiment is an appropriate animal model for the research of explosive effect on facial nerves because of its controllable and repeatable injuring conditions.</p>

Clinical characteristic and treatment of maxillofacial trauma in the elderly / 中华老年医学杂志

Objective To analyze the clinical characteristic and provide therapeutic techniques of maxillofacial trauma in the elderly. Methods Geriatric maxillaofacial trauma patients admitted to our hospital from January 1992 to December 2002 was retrospectively reviewed. Data were collected according to etiology, location, comorbidities, associated injuries, therapeutic methods and the outcome. The patients were compared with a control group consisting of 200 young and adult patients admitted at the same period. Results For the 126 geriatric trauma patients, the major causes were traffic accidents(61.1%) and violence assault(25.4%). A large proportion of facial injuries occurred on the lower part of the face. 69.1% of the patients presented with preexisting diseases. Most of the fractures were not treated(35.7%). The length of hospitalization and ICU stay were relatively longer when compared with the control group(P

The character of glial line-cell derived neurotrophic factor mRNA expression in a facial nerve-striking model / 华西口腔医学杂志

<p><b>OBJECTIVE</b>It has been known that glial line-cell derived neurotrophic factor (GDNF) has the nutritional and protective effect in motor neurons. In this experiment, we investigated the character of GDNF mRNA expression in a facial nerve-striking model; combined with other scholars' experimental results; and analyzed what role GDNF plays in the regeneration process of injured motor nerves.</p><p><b>METHODS</b>We established a striking model in rabbit facial nerves with a striking gun with the striking velocity of 10 m/s and the total striking energy of 7.5 J. Then we detected the GDNF mRNA expression in facial neurons and axons with in situ hybridization on days 3, 7, 14 and 21 after striking. We counted the expression numbers of facial neurons and, compared with normal facial neurons and peripheral facial nerves.</p><p><b>RESULTS</b>We detected GDNF mRNA expression in the facial neurons from day 3 to day 21 after the facial nerve injured by striking. The peak of GDNF mRNA expression appeared on the 7th day, and then the expression number of facial neurons decreased gradually. A high level expression was also detected on day 21. GDNF mRNA expression was not detected neither in Schwann cells nor in normal facial neurons from the 3rd day to the 21st day.</p><p><b>CONCLUSION</b>GDNF is a kind of neurotrophic growing factor (NGF) that could be activated by injury. The character of GDNF mRNA expression was accordant to the process of nerve regeneration. These results showed that GDNF plays a very important role in the regeneration of injured motor nerves.</p>

Expression of vascular endothelial growth factor during the early stage of maxillofacial blast injury / 重庆医学

Objective　To determine the expression and the change of vascular endothelial growth factor(VEGF) and it's acceptor Flt-1 during maxillofacial blast injury at early stage,and to evaluate the effect of VEGF on traumatic wound healing.Methods　The rabbit model of maxillofacial blast injury was made by KTY-04 blasting cap. The expression of VEGF and Flt-1 in wound tissue was determined by ABC immunohistochemistry after injury 6h,1d,2d,3d,5d,and 7d. Also,the results were compared with preinjury groups.Results　In the wound tissue of maxillofacial blast injury, the expression of VEGF was rising steadily at the first week after injury. Comparing with normal tissue,it showed different from the first day after injury, and showed very different from the third day(P<0.01).It reached the peak at the seventh day after injury.The expression of Flt-1 showed no difference within 3 days after injury comparing with normal tissue.After injury 5d-7d,the protein expressed strengthly.Conclusion　The stage of the VEGF expression at maxillofacial blast injury is similar to the angiogenic stage during wound healing, and the Flt-1 expression is also occurring at that period.It illustrates that VEGF take part in angiogenic cascades of traumatic wound healing and product auxo-action to the regeneration of blood vessel.

Prolonging of mandible after loss of periosteum and inferior alveolar vessels in rabbits / 实用口腔医学杂志

Objectives: To study the prolonging of mandible by distr ac tion osteogenesis (DO) after severe trauma in rabbits. Methods:O steotomy was conducted in 16 adult rabbits. To simulate severe trauma,periosteum was removed and inferior alveolar vessels were destroyed on left side. The rabb its were randomly divided into 4 groups with 4 in each group and internal distra ctor was applied in each rabbit. In group A1 and A2 the latency time was 1 day,i n group B1 and B2 that was 7 days.In group A1 and B1 the distraction velocity wa s 0.5 mm/d,in group A2 and B2 that was 1.0 mm/d.The distraction length was 10 mm and retention period was 4 weeks. Results:4 weeks after operati on on right side complete new bone formation was found in the distraction area. On left side that was observed in group B1 and B2,but not in A1 and A2.Nonunion was found in 1,4,0 and 0 cases in group A1,A2,B1 and B2 respectively.The bending strength (10 4 N/m 2) of normal bone was 95,that in group A1,B1,B2 was 25,85 and 60 respectively. Conclusion:DO method can be used even after the blood supply of the mandibles has been destroyed, but the latency period sh ould be longer.

Evaluation of compression and non-compression internal fixation for mandibular fractures / 实用口腔医学杂志

Objective: To observe effects of treatment of mandibular fractures with compression or non compression internal fixation. Methods: In the in vivo study mandibular fractures were fixed by compression internal fixation on one side and non compression on other side in 15 dogs and observed radiologically and histologically. In clinical practice 42 patients with 58 mandibular fractures were treated with compression internal fixation, and 56 patients with 78 madibular fractures were treated with non compression internal fixation. Their clinical effects were evaluated by masticatory efficiency test, radiological and clinical observation after operation. Results: Primary bone healing was found histologically in group of compression fixation and bone healing through callus in group of non compression in the dogs. In the patients treated with compression internal fixation bone fracture line disappeared 1 week earlier and masticatory efficiency was heigher than in those with non comprission fixation. Conclusion: Both methods are all effective in the treatment of mandibular fractures. The miniplate is convenient in use and the indication is wide ranging. The compression plate can speed healing of mandibular fractures, but the operation is more strict technically.

THE PATHOLOGY OF DOGS′ FACIAL NERVE AFTER SIMULATED EXPLOSIVE WOUND OF MAXILLOFACIAL REGION / 解放军医学杂志

To observe the injury process and pathological changes of the facial nerve,a primer was detonated at a distance of 10 cm from the face of each of 36 anesthelized dogs to simulate blast injury of the maxillofacial region. At the same time, a tangential wound of masseter was produced by a steel pellet fired with a musket to simulate a shrapnel injury. At different time points after injury, the action potential of the facial nerves was checke d and the pathological changes in axons and neurons of facial nerves were observed after HE and Nissle′s staining,respectively.One day after the injury,the facial nerve axons were found to be disrupted extensively,although the epineurium was still in continuity. There were degeneration and necrosis of neurons with infiltration of inflammatory cells in the facial nerve.One week later, the inflammation began to become milder, and the necrotic neurons were gradually absorbed. Four weeks later, the survived neurons appeared normal, and axons began to regenerate. Meanwhile, electromyography (EMG) showed that the action potential of facial nerve recovered. All the observations suggested that severe indirect injury to the facial nerve trunks in an explosive injury was the main pathological changes which involved an extensive area with severe damage in neurons.

Biomechanical characters of human mandible under compression load / 实用口腔医学杂志

Objective:To study the biomechanical characters of human mandible under compression load and to deduce the constitutive equation.Methods: Specimens taken from five mandible of fresh human cadavers were examined on INSTRON by a group of tensile tests at different strain rates (0.000　5,0.005,0.05 and 0.5 s-1).Bone mineral density of every individual mandible was measured.The effects of strain rate(**),bone mineral density (ρ) on Young'Modulus (E),strength(σu)and ultimate strain(εu) were studied and the constitutive equations were deduced using the following model:Y=aρb**c.Results:(1)σu=216.27ρ1.23**0.055（P<0.01），(2)E(Pa)=5　604.024**0.083（P<0.01）,(3)εu =0.045**-0.045（P<0.01）,(4)σu=1　798.87ρ-1.17**0.083ε0.82（P<0.01).Conclusions:Strain rate and bone mineral density are important factors for the biomechanical characters of human mandible under compression load.Based on the constitutive equations,the stress level,the possibility and degree of mandible injury may be estimated.

EXPRESSION OF IL-2 GENE IN INJURED TISSUE OF MAXILLOFACIAL FIREARM TRAUMA / 解放军医学杂志

To investigate the temporal variation of cell-mediated immunity in injured tissue of maxillofacial firearm trauma. Cells expressing messenger RNA(mRNA) for IL-2 were demonstrated by dot blotting and in situ hybrization in injured tissue of maxillofacial trauma inflicted by bullet, in conjunction with immunohistochemistry for IL-2 in normal and postinjury conditions. It was found that, apart from a transient eleratim in level within 24h post injury, both IL-2 production and IL-2 mRNA expression were consistently suppressed in cells at the site of the wound compared with the normal. The changes in the tissues of indirect injury by the projectile were significant. These results indicate that the cell-mediated immunity was suppressed in maxillofacial firearm trauma and the principal cellular abnormalities that resulted in altered T cell activation and IL-2 production postinjury was downregulation of mRNA before IL-2 gene transcription. It also suggested that the indirect injury by projectile contribute mainly to the depression of cell-mediated immunity.

Characteristics and management of 301 cases of civilian firearm injuries in maxillofacial region / 实用口腔医学杂志

Objective: To view the characteristics and the primary treatment of civilian firearm wound in the maxillofacial region.Methods: 301 cases of the casualties admitted to our hospital were retrospectively investigated,the epidemic, etiology, wound characteristics, and treatments of the patients were viewed respectively. Results: Of all the cases, the ratio of male to female was 5.1∶1.0. 57% of the injuries were caused by gunshot, 66% were with multiple injuries.16% combination wound were craniocerebral injuries. In this group of patients, more than 900 wound tracks were found, 72% of the tracks were nonpenetrating and 67% of those were with foreign bodies lodged in. Burns with blast injuries were the main complex wounds, which mostly occurred in explosion. The treatments mainly included life maintaining, earlier debridement and infection control. Conclusions: The maxillofacial firearm injuries are complex and have their own characteristics depending on the firearms, the wound styles and the regional anatomy. All the factors must be considered when treatment is given.

Early expression of tumor necrosis factor alpha in blood after gunshot wounds in dogs / 第二军医大学学报

Objective: To study the pathophysiological role of tumor necrosis factor ? (TNF ?) and interleukin6 (IL 6) in trauma by assaying concentration of TNF ? in blood after maxillofacial gunshot wounds in dogs. Methods: Before and after gunshot wounds, concentration of TNF ? and IL 6 in the plasma of dogs were assessed by ELISA method at different times. Results: Although the systemic injuries in our gunshot wound model were no very severe and the dogs had no severe complications, the TNF ? concentration in plasma became significantly higher in the first 2 6 h after the gunshot wounds. They varied greatly with each dog and became normal after 10 h without treatment. IL 6 was not detected in blood. Conclusion: TNF ? expression in blood after gunshot wounds is the normal host immune response to the trauma, its circulating concentrations might be associated with the injury severity. But their transient expressions do not significantly increase the severity of the trauma. [

A new animal model for the study of explosive injury in maxillofacial region / 实用口腔医学杂志

Objective: To establish an efficient animal model for the study of explosive injury in maxillofacial region.Methods: The detonator, steel spheres as fragments simulants shot by smooth-bore barrel and a synchronizer were used to define the wound model in the maxillofacial region of 18 dogs. The whole system was triggered when shooting. Wounding parameters and the changes of targets after explosion were observed and recorded. Results: The overpressure of blast wave decreased exponentially according to the distance from explosive. After injury, the local damage of dogs was serious and extensive compounded with the damages in heart, lung and brain. The injury was aggravated with the increasing of over pressure and energy absorption. Conclusion: The new wound model can be used for the study of explosive injury in maxillofacial region that is characterized by serious tissue damage and multi-etiology.

Effect of recombinant human basic fibroblast growth factor on cell proliferation during mandible fracture healing in rabbit / 实用口腔医学杂志

objective: To investigate the effect of recombinant human basic fibroblast growth factor (rhbFGF) on cell proliferation during mandible fracture healing. Methods 8 ?g of rhbFGF in 0.3 ml of H 2O was mixed with 1.6 ml of bovine type 1 collagen and then the mixture was vacuumed to be a membrane. The membrane was implanted around the mandibular fracture following the fracture was made in 25 rabbits. 5 animals were sacrificed 1,2,4,8 and 12 weeks respectively after operation. Proliferating cell nuclear antigen (PCNA) in callus was examined with immunohistochemical staining. Type 1 collagen membrane was used as the control in another 25 rabbits. Results:1 week after operation, PCNA positive cell(%) in callus in rhbFGF treated and control group were 65.2?6.1 and 32.0?5.5 respectively ( P

The effect of glial cell line derived neurotrophic factor on facial nerve regeneration following injury / 实用口腔医学杂志

?Objective: To study the effect of glial cell line derived neurotrophic factor (GDNF) on facial nerve regeneration after injury.Methods:Defect of 5 mm was made in each facial nerve on both sides in 32 rabbits.Silicon tubes were used to bridge the defects.Pure GDNF (15 ?g in 30 ?l silane) was injected into silicon tube on one side and saline (30 ?l) on the other side as the control.Nerve regeneration was studied by morphological observation with HE and Bielschowsky stainning,counting of nerve neurons and axon and measuring of motor nerve conduction velocity.The rest 3 rabbits was as blank contol. Results:7 d and 17 d after operation ,the neuron number in GDNF treated and control groups were 39.2?2.3 and 28.4?1.9,and 33.6?2.1 and 27.1?1.4,respectively ( P

Immunohistochemical study on the expression of IL-6, IL-8 and TNF-? in gunshot wounds in soft tissues / 第二军医大学学报

Objective: To study the relationship between interleukin(IL) 6, IL 8, tumor necrosis factor alpha (TNF ?) and wound healing. Methods: In lower jaw gunshot wound, the expression of IL 6, IL 8, TNF ? in local soft tissues was assayed by using immunohistochemistry methods. The current levels of IL 6, IL 8, TNF ? in wound tissues was analysed by using image assay. Results: High expressions of these cytokines were observed in local soft tissues of wounds during the first 3 d after the gunshot. The cytokines expressions were different between the area near the bullet path and that far from the path. There was only one peak of the cytokines concentration in the area far from the bullet path, while there were 2 peaks of the cytokines concentration in the area near the bullet path.Conclusion: These results suggest that IL 6, IL 8, TNF ? play an important role in regulating inflammatory reactions of local injured tissues. They may improve the functions of fibroblasts, mononuclear phagocytes and endothelial cells and stimulate wound cells to produce and release other cytokines.

Effects of extraneous rh-TNF-? on wound healing / 第二军医大学学报

Objective: To study the effects of TNF ? on wound healing. Methods: The skin lesion and incisions were made on mice and rh TNF ? was applied in both skin lesion and incision. Tissue strips were evaluated for tensiometry and histologic features after healing. Results: It was found that rh TNF ? markedly improved wound healing both in skin lesion and incision wound model, it also markedly enhanced the breaking strength of treated incision and increased wound cellularity in rh TNF ? treated groups. Conclusion: The results suggest that TNF ? play an important role in regulating inflammatory reactions of local injured tissues and it may improve the functions of fibroblasts, mononuclear phagocytes and endothelial cells. rh TNF ? of suitable doses can promote wound healing. This shows that TNF ?, as a wound healing promoter, has the potentials for clinical application.

Effects of L-arginine on the expression of nitric oxide synthase in facial nerve in traumatic facial paralysis rats / 实用口腔医学杂志

Objective :To study the effects of NO precursor, L-arginine(L-Arg) and constitutive nitric oxide synthase(cNOS) inhibitor, L-nitroarginine(L-NNA)) on the expression of cNOS in facial nerve and surrounding tissues in traumatic facial paralysis rats. Methods:Facial paralysis was surgicaly created by impact in 57 SD rats. The rats were divided into 3 groups with 18 in each group, another 3 rats were used for morphological study. L-Arg at 40 mg/kg or L-NNA at 50 mg/kg were intraperitoneally injected into rats 2 times a day, from 4 days before untill 14 days after surgery(group L-Arg and group L-NNA). In control group(NS) same volume of normal saline was given to the rats after creation of facial paralysis. The facial nerve and surrounding tissue samples were obtained at different time. Immunohistochemical ABC method was used to examine cNOS and inducible NOS (iNOS) expression in facial nerve and surrounding tissues. Results:cNOS immunoreactivity was observed in traumatic facial nerve in L-Arg group 7 days after trauma and in the adjacent muscle in the 3 groups from 6 h to 3 d after trauma. iNOS was found in the paralyzed nerves from 1 d to 7 d after trauma in the 3 groups, and in the adjacent tissues from 6 h to 3 d after trauma in the 3 groups. Conclusions:L-Arg may stimulate constitutive NOS expression in facial nerve and probably promote the nerve regeneration.

Comparative study between the characteristics of facial nerve jnjury resulted from gun-shot and that from blast / 实用口腔医学杂志

Objective: To study the difference between the facial nerve injury by gun-shot and that by blast. Methods: 40 adult dogs were divided into 2 groups, with 20 dogs in each. In the blast group, the impact wave was simulated by detonator blast in the distance of 10 cm over the dog's masseter. At the same time,a steel ball was projected to the dog's face by a rifle to imitate segments in blast. In the gun-shot group, only the steel ball was used. Then the facial nerve was taken at the time of immediateness, 6 hours, 1 day, 3 days and 7 days following the injury for HE or immunocytochemical staining. And the facial nerve conduction velocity was examined 6 hours, 3 days and 7 days after injury.Results: The facial nerve edema was found in both groups just after injury. There was scattering hemorrhage and little hematoma below the spineurium in the gun-shot wound, as well as the diffusing bleeding and larger hematoma in blast wound. In the blast group, the severe edema could be found by light microscope in the whole extracranial facial nerve. Axonal fragments, infiltrating imflammatory cells and few neurofilament protein NF positive axons were observed. In the gun-shot group, only scattering damage was found within 2 cm from the wound track.Conclusion: The facial nerve injury by gun-shot bacomes less severe with the increase of distance from the wound track, but the blast injury is wider and more severe.