Trismus originating from rare fungal myositis in pterygoid muscles:A case report

BACKGROUND Trismus is a common problem with various causes.Any abnormal conditions of relevant anatomic structures that disturb the free movement of the jaw might provoke trismus.Trismus has a detrimental effect on the quality of life.The outcome of this abnormality is critically dependent on timely diagnosis and treatment,and it is difficult to identify the true origin in some cases.We present a rare case of trismus due to fungal myositis in the pterygoid muscle,excluding any other possible pathogenesis.CASE SUMMARY The patient presented with a 2-mo history of restricted mouth opening.Computed tomography showed obvious enlargement of the left pterygoid muscles.Furthermore,the patient had trismus without obvious predisposing causes.The primary diagnosis was pterygoid myosarcoma.Consequently,lesionectomy of the left pterygoid muscle was performed.Intraoperative frozen biopsy implied the possibility of an uncommon infection.Postoperative pathologic examination confirmed myositis and necrosis in the pterygoid muscle.Fungi were detected in both muscle tissue and surrounding necrotic tissue.The patient recovered well with antifungal therapy and mouth opening exercises.The rarity of fungal myositis may be responsible for the misdiagnosis.Although the origin of pathogenic fungi is still unknown,we believe that both hematogenous spread and local invasion could be the most likely sources.To the best of our knowledge,this is the
rst case in the literature that reported fungal myositis in pterygoid muscles as the only reason that results in trismus.CONCLUSION Surgeons should remain vigilant to the possibility of trismus originating from fungal myositis.

Experimental Study on Anatomic Reduction of Lateral Pterygoid Muscle(Simulated Manipulation Fracture Reduction)and Condylar Free Reduction for Condylar Fracture

[Objectives]To compare the fracture healing of keeping lateral pterygoid muscle anatomic reduction(simulated manipulation fracture reduction)with condylar free reduction in the treatment of condylar fractures.[Methods]Twenty-four New Zealand rabbits were randomly divided into two groups to mandibular condylar neck fracture model was established.one team keep the lateral pterygoid muscle,the other excise it.Cervical vascular perfusion was done with ink before animals executed after operation 2,4,6 and 8 weeks.Bilateral anteroposterior and mediolateral condylar diameters measured.Changes of operation side condylar proliferating layer,microvessel number and bone parameters were observed and analyzed after slices and HE staining.[Results]The mediolateral condylar diameters of operation side were significantly smaller than health side in condylar free reduction group at the 4,6,8 weeks(P<0.05),but there was no statistical difference in the anteroposterior condylar diameters at each time point(P>0.05).There were no significant differences in the anteroposterior and mediolateral condylar diameters of the anatomic reduction lateral pterygoid muscle group compared between the operation side and health side(P>0.05).The number of microvessel in condylar free reduction group were smaller than those in anatomic reduction lateral pterygoid muscle group(P<0.05).There were significant differences in BV/TV,Tb.Th,Tb.Sp between the condylar free reduction group and the anatomic reduction lateral pterygoid muscle group(all P<0.05),and the Tb.N were significantly differences between two groups at the 4,6,8 weeks(P<0.05).[Conclusions]When the condyle is fractured it should keep lateral pterygoid muscle(manipulation fracture reduction)as possible,which is important in the fracture healing and functional recovering of mandibular.

Medial Pterygoid Myositis Complicated by Numbness of the Tongue and Nonodontogenic Toothache: A Case Report

A 34-year-old woman visited our clinic with complaints of trismus, numbness in the left half of the tongue, and pain in tooth 34. At the patient’s initial visit to our clinic, the maximum assisted jaw opening movement was 20 mm, pointing to severe trismus. The patient complained of spontaneous pain in tooth 34 but did not evince percussion pain. Her pain remained unchanged even under local anesthesia. Radiography showed no pathological findings. A tenderness test of masticatory muscles failed to induce pain. The presence of severe trismus argued against temporomandibular disorders, resulting in suspicion of other inflammatory disease. In view of numbness of the tongue, other diseases such as inflammation or neoplastic disease in the head and neck region were considered. The patient was referred to the departments of neurosurgery and otolaryngology for examination. The results of MRI and CT diagnosis led to the identification of acute myositis of the left medial pterygoid muscle requiring the prescription of nonsteroidal anti-inflammatory drugs, and relaxation of mandibular muscles. With time, maximum unassisted jaw opening improved and pain in tooth 34 ceased, but tongue numbness persisted. The condition was attributed to compression of lingual nerve (LN) and mandibular nerve (MN) resulting from medial pterygoid muscle inflammation.

Lingual Nerve Entrapment in Muscular and Osseous Structures

Running through the infratemporal fossa is the lingual nerve （i.e. the third branch of the posterior trunk of the mandibular nerve）. Due to its location, there are various anatomic structures that might entrap and potentially compress the lingual nerve. These anatomical sites of entrapment are： （a） the partially or completely ossified pterygospinous or pterygoalar ligaments; （b） the large lamina of the lateral plate of the pterygoid process; and （c） the medial fibers of the anterior region of the lateral pterygoid muscle. Due to the connection between these nerve and anatomic structures, a contraction of the lateral pterygoid muscle, for example, might cause a compression of the lingual nerve. Any variations in the course of the lingual nerve can be of clinical significance to surgeons and neurologists because of the significant complications that might occur. To name a few of such complications, lingual nerve entrapment can lead to： （a） numbness, hypoesthesia or even anesthesia of the tongue’s mucous glands; （b） anesthesia and loss of taste in the anterior two-thirds of the tongue; （c） anesthesia of the lingual gums; and （d） pain related to speech articulation disorder. Dentists should, therefore, be alert to possible signs of neurovascular compression in regions where the lingual nerve is distributed.