Image evaluation of suprazygomatic masticator space lesions.

In order to understand lesions involving the suprazygomatic masticator space (SZMS) demonstrated on computered tomography (CT) or magnetic resonance (MR) images, we collected 45 cases of lesions in SZMS. There were hematomas in 26 cases, tumors in 16 cases, and abscesses in 3 cases. The location of these lesions in compartments of the SZMS and adjacent structures was analyzed. Most commonly hematoma was found in the deep loose connective tissue (80.8%), followed by the superficial dense connective tissue (61.5%). Only 2 SZMS hematoma involved the superficial fat pad. Five patients had air accumulation in the SZMS, and all were in the deep fat pad and with maxillary sinus fracture. Of the sixteen cases which were tumors, 12 were extended from adjacent structures, and four were primary tumor. In cases of tumor, compartments of SZMS involved most frequently were temporal muscles (15 of 16 cases), followed by deep fat pad (8 of 16 cases). The connective tissue layer of SZMS is a communication pathway for superficial spread of infection, hematoma, or tumor invasion to or from the scalp and face. Compartments of deep fat pad and temporal muscle are also pathways for the spread of disease to or from the face, intracranium and orbit. The primary tumors in infratemporal fossa and SZMS are rare. Malignant tumors in SZMS usually come from surrounding spaces.

[Observation in vivo histological response induced by imlplanted domestic poly-DL-lactic acid plates]

OBJECTIVE:To analyze the histological response and biocompatibility to implanted domestic PDLLA plates in vivo METHODS:Bilateral artificial fractures were created in mandibular bodies in dog and internal fixed with domestic PDLLA plate,TM plate respectively;meanwhile,a domestic PDLLA plate was imlplanted in femur.The interfacial soft tissue around the plates were collected and performed histological study RESULTS:All the skin wound healed well without abscess and fistula formation. From 2 to 4 weeks after the operation,the inflmmatory granulomatous response around the intenal fixation PDLLA plates was more serious than that of the control,in which more macrophages,plasmocytes and less lymphocytes,mononuclear cells infiltrated CONCLUSION:Domestic PDLLA plate is an inert internal fixation material with good biocompatibility, which induced a non-speciflc foreign reaction

Experimental study of radiation effect on the mandibular microvasculature of the guinea pig.

OBJECTIVE: This experimental study was performed to explore the intraosseous microvascular alterations in the irradiated mandible and to increase understanding of the pathogenesis of osteoradionecrosis. METHODS: One hundred twenty-eight guinea pigs were grouped according to different radiation sources and dosages. Fractioned radiation was delivered to the right mandibles. Dental extractions were conducted at 1, 3, and 5 months respectively, after radiation. One month later, the animals were examined by means of gross observation, histopathology, and microvascular corrosion castings. RESULTS: Histologic evaluation showed bone absorption within 2 months following radiation. Four months later, the number of osteocytes decreased and pyknosis and empty lacunae were commonly seen. The casting specimens revealed under scanning electron microscopy that capillary disconnection and obliteration with subsequent vein shrinkage aggravated over time. In the nonhealing dental extraction site, a large-scale vascular network defect presented with focal capillary proliferation around. CONCLUSIONS: The capillary is the part most vulnerable to the damage caused by radiation in the vascular system of the mandible. On the basis of "hypovascular, hypoxic, hypocellular" structure, local microcirculation failure induced by the trauma-repairing process leads to occurrence of osteoradionecrosis of jaws.

[A comparison of the effects of 180kv X-ray radiation and cobalt-60 radiation on the jaws of the guinea pigs]

OBJECTIVE: Study of the effects of 180kv x-ray and cobalt-60 radiation on jaws and enhance the understanding of pathology of osteroradionecrosis of jaws(ORNJ).METHODS: 128 guinea pigs were grouped according to different irradiation sources and doses.Fractioned radiation from both sources was delivered in right mandible.The teeth extractions were conducted one week prior to radiation and 1,3,5 months after radiation respectively.Following radiation,the guinea pigs were examined by gross observation, x-ray film and histopathological examination at regular interval. RESULTS: Bone resorption occured within 1 month after irradiation as result of osteoblast inhibition and osteoclast activation.From 2 to 4 month afterwards,the number of osteocytes reduced and pyknosis, empty lacunae as well as obliteration of small vessels in periodontal membrane were commonly seen.The teeth extractions conducted at 3 months,5 months after radiation lead to ORNJ in 7 amimals (14.6%).CONCLUSION: 180kv x-ray radiation was far more damaging to jaws than cobalt-60 radiation.The dental extraction is an important factor inducint the development of ORNJ.

[The advanced studies on surgical treatment about the patients of TMJ ankylosis and OSAS]

OBJECTIVE: Through the treatment on the 10 patients suffered TMJ ankylosis and OSAS,by means of the TMJ reconstruction combining orthognathic surgery,it is demonstrated that the treatment on the patients must include relieve the TMJ anklosis,correct the maxillofacial deformitis and specially enlarge upper airway space.

[The pre-and-postoperative cephalometric evaluation on the patients of TMJ ankylosis with OSAS]

After taken the comparative studies on the cephalometric analysis of the patients of TMJ ankyolsis with OSAS pre-and-post operation,the authors demonstrated the method combining TMJ reconstruction and orthognathic surgery is responsible to the patients.

[The pre-postoperative polysomnographic evaluation on the patients of TMJ ankylosis with OSAS]

Passing by the comparative studies on the polysomnogram of the patients of TMJ ankylosis with OSAS pre-and-postoperation,the result showed the patients' AI (Apnea Index;AI) has been decreasing,SaO(2) during sleep get to rise,and the method combining TMJ reconstruction and orthognathic surgery is effective to the patients.

[The treatment of unilateral true ankylosis of TMJ with maxillomandibular deformities]

The authors described a surgical procedure for the treatment of unilateral true ankylosis of TMJ with maxillomandibular deformities.The surgery included arthroplasty and Le Fort I maxillary osteotomy in one or two stages.It successfully not only restore the stomatognathic function with a maximum mouth opening in normal range,but also corrected malpositioned maxilla and mandible normal anatomic position.Postoperative orthodontic anatomic position.Postoperative orthodontic treatment was also performed for the improvement of masticatory function.The indications of the surgical procedure,and intraoperative precautions are discussed.

[Reconstruction of post-traumatic maxillofacial deformity: Analysis of 100 cases]

This paper collects 100 cases with post-traumatic maxillofacial deformity.The types of deformity may be involved by order to concave appearance restricted opening of jaw,disturbance of occlusion,mimetic paralysis,scar,etc.The author advocate the treatment must be paid attention both appearance and function.Recently,we have used the vascularized flap,coronary incision,orthognathic surgery and rigid internal fixation in these cases,and have gotten better result than past.This paper emphasizes that we should pay attention to emergency treatment to reduce the occur of post-traumatic deformity.

[Orthognathic surgery of dentofacial deformities post surgerical repairing of cleft palate and lip.].

10 cases with maxillary development limited post surgical repairing of cleft palate and lip were undergone modified Le Fort I segmental osteotomy,that is,put the maxilla forward without velopharyngeal function change and oro-nasal fistula.By Computer Aided Simulation System for orthognathic surgery(CASSOS),analysis of dental pulp,evaluation of velopharyngeal function,compacting profile pre-to-post operation, authors described that surgical procedure has the satisfactory effectiveness.

[The study of assessing methods for velopharyngeal function in patients with operated cleft palate]

This paper describes the study and quantitative analysis of velopharyngeal function in 103 patients with operated cleft palate using NPF,vedio-camera system and computer.The percentange of semi-circluar and circular closure patterns after surgery was distinct higher in VPI group than in VPC group,but coronary closure pattern was significant lower in VPI group than in VPC group(P<0.05).We compared the results of different operative age by VPI after surgery.The results showed that postoperative RVPI was in direct proportion to operated age.VPI in the group less than 3 years of age.VPI in the group less than 3 years of age was 28.57%,but in the group of over 7 years of age was 96.43%.Both showed significant difference(P<0.01).

Evaluation of free flaps transferred by microvascular anastomosis in oral and maxillofacial surgery.

The authors discuss indications for the use of microvascular free flaps transferred to the oral and maxillofacial region. A series of 139 cases, involving 145 free flaps, is reported over a three year period. The overall success rate for all types of flaps was 89.3%. Advantages and disadvantages of the use of various flaps are presented and suggestions are offered to avoid complications.