Masticator Space Research Articles

Diagnostic value of computed tomography, magnetic resonance imaging, and scintigraphy in diagnosing actinomycosis of the mandible

Mandibular actinomycosis is an uncommon disease caused by Actinomyces israelii. Actinomycosis infection typically manifests as a chronic disease resulting in multiple abscesses, firm soft tissue mass, and presence of sulfur granules in exudates or tissues. A few reports have provided imaging findings of actinomycosis in the head and neck, but computed tomography (CT), magnetic resonance imaging (MRI), and scintigraphy of mandibular actinomycosis have not been fully described. Here, we report a case of mandibular actinomycosis with CT, MRI, and scintigraphy. The purpose of this article is to characterize the CT, MRI, and scintigraphy findings in cases of actinomycosis. Contrast-enhanced CT of the masticator space showed heterogeneous enhancement and a nonenhancing portion, suggestive of necrotic foci. Bone tissue algorithm CT showed an osteolytic lesion in the ramus of the left mandible only. On post-contrast T1-weighted images, the masticator space showed heterogeneous enhancement and nonenhancing portion, suggestive of necrotic foci. Bone scintigraphy revealed monostatic involvement of the mandible with a homogeneous intense uptake pattern. Gallium scintigraphy revealed significantly increased uptake in the left side of the face. These findings can be helpful for differentiating actinomycosis from other tumors of the mandible.

The diagnosis and treatment strategy for patients with severemultispace abscesses in neck

Objective:To analyze the clinical characteristics of patients with severe deep neck abscess,etiology,imaging,appropriate treatment selection in those patients,to improve the judgement and understanding of the disease.Method:Thirty cases of severe deep neck abscess treated from March 2010 to June 2015 were retrospectively reviewed,including the clinical characteristics,diagnosis and treatment strategy.Result:The sore throat,odynophagia,dysphagia,fever and difficulty breathing were the most common symptoms of severe deep neck abscess.The causes of deep neck abscess were tooth diseases(5 cases),foreign bodies in pharynx or esophagus(4 cases),the second branchial crack cyst with multiply abscess,uncertain cause(20 cases).Six of the above cases complicated with mediastinal abscess.Radiologic evaluation was performed on all of the patients to identify the most probable location of the abscess:parapharyngeal space,retropharyngeal space,masticator space,carotid space,etc.Twenty-five cases were treated by drainage via incising lateral neck and 4 patientsreceived abscess puncture aspiration.Life-threatening complications were developed in all cases,29 cases were cured but one case dead.Conclusion:The treatment of severe deep neck multispace abscesses should be mindful.Once deep neck abscesses are diagnosed,we should timely undertake surgical drainage via incising lateral neck.Emergency tracheostomy should be perform in some case like severe dyspnea,airway obstrucion.Antibiotics should be appropriately applied,and basic diseases and complications should be carefully controlled.

Airway management in patients with deep neck infections: A retrospective analysis.

Securing the airway in patients undergoing surgical intervention to control a deep neck infection (DNI) is challenging for anesthesiologists due to the distorted airway anatomy, limited mouth opening, tissue edema, and immobility. It is critical to assess the risk of a potential difficult airway and prepare the most appropriate airway management method.We reviewed our anesthetic experiences managing patients with DNIs, focusing on the need for video-laryngoscope or awake fiberoptic intubation beyond a standard intubation from the anesthesiologist's perspective.When patients had infections in the masticatory space, mouth of floor, oropharyngeal mucosal space, or laryngopharynx, their airways tended to be managed using methods requiring more effort by the anesthesiologists, and more extensive equipment preparation, compared with use of a standard laryngoscope. The degree to which the main lesion influenced the airway anatomy, especially at the level of epiglottis and aryepiglottic fold was related to the airway management method selected.When managing the airways of patients undergoing surgery for DNIs under general anesthesia, anesthesiologists should use imaging with computed tomography to evaluate the preoperative airway status and a comprehensive understanding of radiological findings, comorbidities, and patients’ symptoms is needed.

Fractures of the posterolateral maxillary sinus: a masticator space blowout injury?

Segmental, depressed fractures of the posterolateral maxillary sinus may occur as a result of trauma to the masticator space, previously described in association with mandibular fractures. The authors hypothesize that the fracture is due to a transient increase in pressure in the masticator space (blow out) and therefore should be seen in association with other regional fractures. Injuries of the masticator space were retrospectively identified by searching the imaging database from January 2014 to November 2014 for keywords that would identify regional trauma. The images were reviewed for segmental depressed fractures in the posterolateral aspect of the maxillary sinus accompanied by herniation of a variable amount of masticator space fat and/or muscle into the adjacent sinus. Three neuroradiologists reviewed the images and agreed by consensus on the presence or absence of a masticator space blowout fracture. Forty-three zygomaticomaxillary complex (ZMC) fractures, 89 mandibular fractures, and 49 isolated zygomatic arch fractures were identified. While all of the ZMC fractures had a maxillary component, 3 of 43 (7.0%) additional fractures met our fracture definition. Five of 89 (5.6%) of the mandibular fractures and 6 of 49 (12.2%) zygomatic arch fractures had an associated posterolateral maxillary fracture. Segmental depressed fracture of the posterolateral maxillary sinus is relatively common, occurring in conjunction with other regional injuries. The authors hypothesize that it is due to a transient increase in pressure in the masticator space and is a separate entity from other fractures of the region that may occur concurrently.

The pterygopalatine fossa: imaging anatomy, communications, and pathology revisited

The pterygopalatine fossa (PPF) is a small, clinically inaccessible, fat-filled space located in the deep face that serves as a major neurovascular crossroad between the oral cavity, nasal cavity, nasopharynx, orbit, masticator space, and the middle cranial fossa. Due to its inherent complex location and connections, it can potentially act as a natural conduit for the spread of inflammatory and neoplastic diseases across the various deep spaces in the head and neck. This review aims to acquaint the reader with the imaging anatomy of the PPF, its important communications, and to identify some major pathological conditions that can involve the PPF, especially in conditions where its involvement can have serious diagnostic and therapeutic implications, such as in perineural tumour spread.Teaching points• The PPF is a small neurovascular junction in the deep face with important to-and-fro connections.• Awareness of anatomy of the PPF and its communications helps to simplify imaging of its pathology.• Perineural tumour spread is clinically the most important pathology in this region.

Maxillary tuberosity fracture and ophthalmologic complications following removal of maxillary third molar

AbstractThird molar removal is one of the most common procedures performed by dentists and oral surgeons. Removal of maxillary third molar is associated with a lower rate of complication compared to the mandible, and maxillary tuberosity fracture or ophthalmologic complications after removal of maxillary third molar are very rare. We report maxillary tuberosity fracture and ophthalmologic complications following removal of maxillary third molar. A 35‐year‐old female underwent removal of left maxillary third molar at private dental clinic. Following the complete extraction, excessive haemorrhage occurred and maxillary tuberosity fracture was seen and the patient was brought by ambulance to our hospital. The bleeding was controlled by vacuum‐formed splint and nasal packing. Computed tomography revealed that lateral maxillary tuberosity and posterior wall of the maxillary sinus was defect and there was a slight intraorbital haematoma via the inferior orbital fissure as well as with extension in the maxillary sinus and adjacent spaces such as buccal, masticator, pterygomaxillary and infratemporal spaces. Because an ophthalmologist noted only slight diplopia in lateral gaze without abnormal signs in other examinations and nasal and oral bleeding were controlled, the surgical treatment was not required. The patient was immediately hospitalised for close observation. Intravenous antibiotics and steroids were administered. Because swelling of the cheek and buccal mucosa was gradually decreasing without further haemorrhage, the patient was discharged 4 days after the extraction. The diplopia was recovered completely 11 days after the extraction.

Proposal for the 8th edition of AJCC/UICC staging system for nasopharyngeal cancer in the era of intensity-modulated radiotherapy

Objective An accurate staging system is crucial for cancer management. With the development of cancer staging systems and therapeutic methods, the applicability and improvement of staging systems should be evaluated constantly. Methods The clinical data of 1609 nasopharyngeal carcinoma patients without metastasis at initial diagnosis, who were admitted to two tumor centers in Hong Kong and Mainland China and received intensity-modulated radiotherapy (IMRT), were analyzed retrospectively based on the 7th edition of the American Joint Committee on Cancer (AJCC) or International Union Against Cancer (UICC) staging system, and all the patients underwent magnetic resonance imaging (MRI) before treatment. Results Among the T3/T4 patients without involvement of other anatomic structures, overall survival (OS) showed no significant differences between the patients with masticator space (medial pterygoid muscle and/or lateral pterygoid muscle) involvement, prevertebral muscle involvement, and parapharyngeal space involvement. The OS was similar between the patients with extensive soft tissue (soft tissues other than the structures mentioned above) involvement and those with intracranial involvement or cranial nerve involvement. Only 2% of the patients had lymph node metastasis>6 cm above the supraclavicular fossa (SCF), with an OS similar to that of the patients with lower cervical lymph node metastasis. Replacing SCF with the lower neck (below the caudal border of the cricoid cartilage) did not affect the risk difference between different N stages. With the proposed T and N staging systems, the OS showed no significant differences between T4N0-2 and T1-4N3 patients. Conclusions After a review by AJCC/UICC staging system preparatory committees, the changes recommended for the 8th edition include changing medial pterygoid muscle or lateral pterygoid muscle involvement from T4 to T2, adding prevertebral muscle involvement to T2 stage, replacing SCF with the lower neck and combining this with a maximum lymph node diameter of>6 cm as N3 stage, and integrating T4 and N3 as stage ⅠVA. These changes result in a better risk difference between adjacent stages and achieve the optimal balance between clinical practicability and global applicability. Key words: Nasopharyngeal neoplasms/radiotherapy; Prognosis; TNM staging system

A mass lesion misdiagnosed as a malignant tumor in the masticator space: a case report

Temporomandibular disorder (TMD) is common, affecting up to 28 % of the population. Inflammatory conditions, developmental abnormalities, and neoplasms involving the masticator space can result in symptomatic TMD, which may present with signs such as pain and trismus. Because TMD treatments, including surgical management, differ according to the underlying cause, imaging plays an important role in identifying the precise category of TMD. Here, we report a case of an inflammatory lesion in the right cheek of a 47-year-old woman with symptoms of TMD from both clinical and radiographic perspectives. Computed tomography and magnetic resonance imaging in the present case showed atypical findings for TMD caused by an inflammatory lesion. This knowledge should be added to the list of possible imaging findings in cases exhibiting TMD.

下顎歯周囲感染症から波及した咀嚼筋隙膿瘍の2症例

The masticator space is located between the masseteric fascia and the pterygoid muscle fascia. Here we report two cases of masticator space abscesses spreading from infections of mandibular teeth. Case 1 is an 85-year-old lady who were referred to Yokohama City University Hospital with a left-cheek swelling and trismus. An enhanced CT scan revealed an abscess extending from the left infratemporal fossa to the temporal fossa. A purulent discharge was observed from her left lower gingiva. We performed surgical drainage under general anesthesia. After infection control, the affected teeth were extracted. Case 2 is an 82-year-old lady who was administered oral bisphosphonate for osteoporosis. She presented to another hospital with fever, trismus and swelling anterior to the right ear after right lower tooth extraction. Because MRI revealed persistent osteomyelitis of her mandible even after antibiotic treatment, she was referred to us. Enhanced CT showed an abscess in the right infratemporal fossa. After surgical drainage similar to Case 1, antibiotics were administered for approximately 4 months to control the osteomyelitis. It is important to recognize that infections of the mandibular teeth can cause an abscess in the masticator space through the pterygomandibular and infratemporal spaces.

頭蓋内から咀嚼筋間隙，下顎骨内にかけて広く進展した三叉神経鞘腫の1例

頭蓋内から咀嚼筋間隙，下顎骨内にかけて広く進展した三叉神経鞘腫の1例

咀嚼筋間隙膿瘍・細菌性髄膜炎から海綿静脈洞血栓症を呈した1例

症例は77歳の女性。左上顎犬歯の破折を契機に食事が摂れなくなり，7日後に37℃台の発熱及び歩行時のふらつきによる転倒を主訴に当院救急外来を受診。髄液細胞数の増加及び脳MRIでの咀嚼筋間隙の膿瘍形成の所見から，細菌性髄膜炎を合併した咀嚼筋間隙膿瘍と診断。抗生剤投与により炎症所見は改善したが，入院7日目に両眼球突出を伴った全方向性の眼球運動障害が出現。D-dimerの上昇，頭部造影CTでの上眼静脈の造影欠損から，海綿静脈洞血栓症と診断。抗生剤投与・膿瘍の穿刺排膿に加えて抗凝固療法を行なうことで，炎症所見及び海綿静脈洞血栓症による眼球運動障害は改善を認め，後遺症なく退院した。海綿静脈洞血栓症は，抗生剤の発達により現在では発生頻度は減少しているものの予後不良の疾患であり，早期診断・治療が重要である。

口腔外傷に起因した咀嚼筋間隙膿瘍の1例

口腔外傷に起因した咀嚼筋間隙膿瘍の1例

Muscular invasion by oral squamous cell carcinoma of the posterior mandibular alveolar ridge is associated with cervical lymph node metastasis.

ObjectivesTo assess the association between muscle invasion by oral squamous cell carcinoma of the posterior mandibular alveolar ridge and cervical lymph node metastasis on the basis of preoperative magnetic resonance imaging (MRI).Materials and MethodsTwenty-six patients with oral squamous cell carcinoma of the posterior mandibular alveolar ridge were evaluated by MRI. The associations between cervical lymph node metastasis and independent factors evaluated by MRI were analyzed. Overall survival was also analyzed in this manner. Representative biopsy specimens were stained with anti-podoplanin and anti-CD34 antibodies.ResultsMylohyoid muscle invasion was associated with cervical lymph node metastasis. A combinational factor of mylohyoid and/or buccinator muscle invasion was also associated with cervical lymph node metastasis. Cervical lymph node metastasis and masticator space invasion had a negative effect on overall survival. No lymphatic vessels were identified near the tumor invasion front within the mandible. In contrast, lymphatic vessels were identified near the front of tumor invasion in the muscles.ConclusionThis study demonstrates an association between muscular invasion by oral squamous cell carcinoma of the posterior mandibular alveolar ridge and cervical lymph node metastasis.

A case of masticator space abscess which caused trismus and bilateral posterior open bite with difficulty in distinguishing from temporomandibular joint diseases

A case of masticator space abscess which caused trismus and bilateral posterior open bite with difficulty in distinguishing from temporomandibular joint diseases

Magnetic Resonance Imaging Findings in Childhood Period Nasopharynx Cancer.

SummaryBackgroundNasopharyngeal carcinoma is a rarely seen tumor in childhood. It is mostly detected late as the clinical features are similar to other childhood tumors which affect the nasopharynx and adenoidal hypertrophy. Therefore, the radiological features of childhood tumors of the nasopharynx must be well known. The aim of this study was to investigate the contribution of MR imaging features of childhood nasopharynx cancer.Material/MethodsThe study included 10 nasopharyngeal carcinoma patients under the age of 18 years who presented at hospital between February 2008 and March 2014 and who had tissue diagnosis and MRI of the nasopharynx region. The MRI scans were evaluated by two radiologists. Loco-regional spread, asymmetry, signal intensity of the tumors, and lymph nodes were evaluated.ResultsIn all the patients there was a mass which narrowed the nasopharynx. In all cases, unilateral mastoid opacification was observed. In 9 cases (90%), parapharyngeal extension was found. In 8 cases (80%), the mass showed an extension into the nasal cavity or oropharynx. In 5 cases (50%), there was an involvement of the skull base. In 3 patients (30%), an extension to the masticator space and pterygopalatine fossa was found. There were enlarged cervical lymph nodes bilaterally in 10 cases (100%). In 4 cases (40%), a lateral retropharyngeal lymph node was detected.ConclusionsChildhood nasopharyngeal cancers are often diagnosed at an advanced stage. MR imaging can be helpful in diagnosis and differential diagnosis of childhood nasopharynx cancer from other diseases of the nasopharynx.

Recurrent pain and swelling associated with impacted maxillary third molar

A 57-year-old woman reporting intermittent severe pain and swelling for 5 years in the left maxillary jaw was evaluated at the oral and maxillofacial surgery clinic at the University of Detroit Mercy School of Dentistry. The pain intensity had increased markedly in the past 2 to 3months. She had difficulty swallowing and opening her mouth, and a bad odor associated with a bloody mucous discharge. Her medical and surgical history included chronic neck pain, arthritis, degenerative disk disease, choroid cyst, headaches associated with Arnold-Chiari malformation, sinus surgery due to recurrent sinusitis, and an eye surgery for strabismus. Her dental history included periodic pain and soreness associated with impacted tooth no. 16. Her health history included a 40 pack-year smoking history, and at the time of her examination she was smoking 1 pack per day. She denied alcohol or illicit drug use. Extraoral examination identified a nonerythematous, firm swelling on the left side of her face without evidence of lymphadenopathy. On the basis of the long-standing pain and swelling, the difficulty in opening, and the history of surgery in the left maxillary sinus, the decision was made to examine the patient with cone-beam computed tomography (CT). This technique permits a view of the anatomy in 3 planes of space. It also provides a larger field of view than panoramic radiographs, which was especially beneficial due to the unknown position of the left third molar. The cone-beam CT scan revealed diffuse opacification of the left maxillary sinus with destruction of the alveolar process and resorption of the walls of the maxillary sinus. The pathologic alterations extended beyond the field of view, and considering the likely involvement of extra-antral soft tissues it was decided that CT was necessary for complete radiographic visualization of the condition. A bone window axial view of the CT scan revealed the lesion in the left maxillary sinus associated with destruction of the anterior, posterior-lateral, and medial walls of the left maxillary sinus, with extension into the pterygopalatine fossa as well as the buccal and masticator spaces (Figure 1). Soft-tissue sections depicted infiltration of the lesion into the medial and lateral pterygoid muscles, and extension into the nasal fossa (Figure 2) and greater palatine foramen (Figure 3). Destruction of the palate and left maxillary alveolar ridge was also observed (Figure 4). Microscopic examination after an incisional biopsy revealed a proliferation of squamous epithelium. Cells exhibiting increased nuclear-cytoplasmic ratios, pleomorphism, individual cell keratinization, and increased mitotic activity were noted (Figure 5).

A comparison of radial forearm free-flap reconstruction and non-reconstruction after partial maxillectomy

ObjectiveThis study aimed to compare postoperative outcomes between free-flap reconstruction and prosthesis after secondary healing for moderate-sized maxillectomy defects. MethodsWe enrolled patients who underwent tumor ablation extending to the alveolus, antral walls, masticatory space, and surrounding soft tissue but not the orbital floor with either radial forearm free-flap reconstruction (RFFF) or no reconstruction (NR) and compared the extent of cheek concavity on the resected side, evaluated using axial computed tomography images, and time to prosthesis insertion between the RFFF and NR groups. ResultsThere was a significant difference between the RFFF and NR groups in operative duration (P=0.010) but not blood loss. The postoperative cheek concavity was significantly smaller in the RFFF group (P=0.037). Although the between group difference in time to prosthesis insertion was not significant, prostheses tended to be inserted earlier in the RFFF group; median time to prosthesis insertion was 49 days in the RFFF group and 67 days in the NR group. ConclusionsReconstruction of a moderate-sized maxillectomy defect with radial forearm free-flap transfer can improve postoperative outcome.

Prognostic value of MRI-derived masticator space involvement in IMRT-treated nasopharyngeal carcinoma patients

ObjectivesThis retrospective study reassessed nasopharyngeal carcinoma (NPC) patients treated with intensity-modulated radiation therapy (IMRT), to determine the significance how magnetic resonance imaging (MRI)-derived masticator space involvement (MSI) affected patients’ prognosis.MethodsOne thousand one hundred ninety seven NPC patients who had complete set of MRI and medical records were enrolled. Basing on their MRI findings, the T-categories of tumors were identified according to the seventh edition of American Joint Committee on Cancer staging system, which considers MSI a prognostic indicator for NPCs. Rates of overall survival (OS), local relapse-free survival (LRFS), regional relapse-free survival (RRFS) and distant metastasis-free survival (DMFS) were analyzed by the Kaplan-Meier method, and the Log-Rank test compared their differences. Cox regression analysis was employed to evaluate various prognostic factors systematically. Statistical analyses were conducted with SPSS 18.0 software, P value < 0.05 was considered statistically significant.ResultsMedial pterygoid muscle (MPM) was involved in 283 (23.64 %) cases, of which lateral pterygoid muscle (LPM) was concurrently affected in 181 (15.12 %) and infratemporal fossa (ITF) in 19 (1.59 %). Generally, MSI correlated with an OS, LRFS, and DMFS consistent with a T4-stage diagnosis (P > 0.05). Although different degrees of MSI presented a similar OS and DMFS (P > 0.1), tumors involving LPM had a relatively poorer LRFS than those affected the MPM only (P = 0.027), even for subgroup of patients composed of T3 and T4 classifications (P = 0.035). A tumor involving MPM brought an LRFS consistent with a T2 or T3-stage disease (P > 0.1). If the tumor affected LPM or ITF concurrently, the survival outcomes were more consistent with a T4-stage disease (P > 0.1). Nevertheless, compared to tumor infiltrating MPM, those invading LPM or ITF more frequently spread into other concurrent sites that earned higher T-staging categories. Moreover, multivariate analyses indicated the degree of MSI was a significant prognostic factor for the OS of NPCs (P = 0.036).ConclusionsDegree of MSI is a significant prognosticator for the OS of IMRT-treated NPCs, and the prognosis of patients with lateral MSI extension (LPM and ITF) were shown to be significantly worse than those affected only MPM or the T3-stage disease. Thus, it is highly recommended that lateral MSI extension be a higher T-staging category.

Correlation between degree of bone invasion and prognosis in carcinoma of the mandibular gingiva: Soft tissue classification based on UICC classification

ObjectiveThe criteria for T4 staging of carcinoma of the mandibular gingiva are controversial. Oral cancer staged as T4 implies “invasion to an adjacent organ” such as the skin, extrinsic muscles of the tongue, masticator space, or mandibular bone. In this study, we compared different T classifications and retrospectively investigated the correlation between each classification and the prognosis of patients with carcinoma of the mandibular gingiva. MethodsWe investigated 81 patients with squamous cell carcinoma of the mandibular gingiva treated at two institutions. ResultsThere was a significant correlation between soft tissue classification and local recurrence (P<0.05) and that the correlation with prognosis is borderline significant (P=0.05). ConclusionsSoft tissue classification, which does not consider bone invasion, was the most useful for diagnosis, selecting the appropriate surgical procedure, and assessing the correlation to prognosis. We recommended using this classification to define T4. Because this classification is not new but is based on International Union Against Cancer classification, it could be easily adopted. However, the current study is a retrospective analysis of a small number of patients. A multi-institutional, prospective study is necessary to determine the appropriate criteria for the TNM staging of carcinoma of the mandibular gingiva.

Pathology of advanced buccal mucosa cancer involving masticator space (T4b).

Buccal mucosa cancer involving masticator space is classified as very advanced local disease (T4b). The local recurrence rate is very high due to poor understanding of the extent of tumor spread in masticator space and technically difficult surgical clearance. The objective of this study is to understand the extent of tumor spread in masticator space to form basis for appropriate surgical resection. All consecutive patients with T4b-buccal cancer underwent compartment resection, with complete anatomical removal of involved soft-tissue structures. Specimens were systematically studied to understand the extent of invasion of various structures. The findings of clinical history, imaging and pathologic evaluation were compared and the results were evaluated. A total of 45 patients with advanced buccal cancer (T4b) were included in this study. The skin, mandible and lymph nodes were involved in 30, 24 and 17 cases respectively. The pterygoid muscles were involved in 34 cases (medial-pterygoid in 12 and both pterygoids in 22 cases) and masseter-muscle in 32 cases. Average distance for soft-tissue margins after compartment surgery was 2 cm and the margins were positive in 3 cases. The group with involvement of medial pterygoid muscle had safest margin with compartment surgery while it was also possible to achieve negative margins for group involving lateral pterygoid muscle and plates.The involvement of pterygomaxillary fissure was area of concern and margin was positive in 2 cases with one patient developing local recurrence with intracranial extension. At 21 months median follow-up (13-35 months), 38 patients were alive without disease while two developed local recurrence at the skull base. T4b buccal cancers have significant soft-tissue involvement in the masticator space. En bloc removal of all soft-tissues in masticator space is advocated to remove tumor contained within space. The compartment surgery provides an opportunity to achieve negative margins for cancers actually contained within masticator space.It is inappropriate to club all patients with masticator space involvement in one group.