Diffuse-type tenosynovial giant cell tumor of the temporomandibular joint with skull base invasion: a report of 22 cases with literature review.

OBJECTIVES: The aim of this study was to retrospectively analyze the clinical characteristics, surgical treatment, and prognosis of patients with diffuse-type tenosynovial giant cell tumor (D-TGCT) involving the temporomandibular joint (TMJ) and the skull base. STUDY DESIGN: A retrospective study was performed in patients with D-TGCT involving the TMJ and the skull base at our institute from April 2009 to August 2018. Data on clinical characteristics, surgical treatment, and prognosis were collected and analyzed. A literature search on D-TGCT involving the TMJ was conducted and the data analyzed. RESULTS: The study included 22 patients (14 males and 8 females), with an average age of 44 years. The main symptoms were headache and hearing limitation, accompanied by a swelling in the TMJ area. Magnetic resonance imaging (MRI) showed low signals on T1- and T2-weighted images. All lesions were completely removed. Temporal bone flap, titanium mesh, and temporal muscle flap were used for reconstruction. The recurrence rate was 4.5%. In the literature, 115 cases were reported. Surgery alone was performed in 88 cases; postoperative radiotherapy was performed in 19 cases; the tumor recurrence rates were 9.1% and 15.8% for the 2 procedures, respectively. All patients were alive at the end of the follow-up period. CONCLUSIONS: D-TGCT involving the TMJ and the skull base is a locally aggressive but benign lesion necessitating complete resection and has a good prognosis.

Sensitivity and fidelity of a novel piezoelectric middle ear transducer.

OBJECTIVE: A novel implantable piezoelectric transducer has been developed in this laboratory. The transfer functions of the transducer were assessed in anesthetized acutely implanted cats, and were compared with the microphone of a cochlear implant's speech processor. METHODS: The piezoelectric transducer was fixed to the head of the malleus of the cat. Pure tone signals of 97 dB SPL ranging from 250 to 8,000 Hz delivered from a loudspeaker placed beside the auricle of the cat were used to vibrate the tympanic membrane. The frequency response of the transducer was measured by monitoring the output signal of the transducer with an oscilloscope. The transfer functions of the transducer were then compared with the standard external microphone receiving the same tonal stimulus. RESULTS: The average sensitivity of the implantable piezoelectric transducer was -38.7 dB re 1 V/Pa at 1,000 Hz. The frequency-response curve of the transducer mirrored that of the external microphone, even with high-frequency stimuli. CONCLUSION: The implantable piezoelectric transducer developed in this laboratory transmits tonal stimuli with high fidelity.

[Embolizing of high flow craniomaxillofacial arteriovenous malformations with superselected endovascular catheterization: report of 9 cases].

OBJECTIVE: Using endovascular embolization to cure and stop the enlargement of craniomaxillofacial AVMs. METHODS: Nine patients with craniomaxillofacial AVMs were treated with endovascular embolization. Among them four were males and five females. The average age was 21 years old. The diagnosis was made according to CT, MRI and DSA angiograpy. PVA particles was used via a microcatheter to embolize the AVMs. RESULTS: In this group,the lesions in six of nine patients were totally embolized by one procedure. The other three cases underwent two procedures. All the lesions were totally embolized. The follow up of eight in nine patients (except one lost) showed a good recovery of the swollen skin around the focus, the colour and the temperature became normal. No complications were observed. CONCLUSION: Endovascular embolization is an effective method to cure the lesions or to stop the enlargement of craniomaxillofacial AVMs with minimal invasion. It is important that this method can avoid damaging the face by surgical resection. We also find that the venous part or the venous pool of the fistulae is the most important part for the lesions to reoccur.