Shinya Yura

Can arthrocentesis release intracapsular adhesions? Arthroscopic findings before and after irrigation under sufficient hydraulic pressure

PURPOSE To investigate the effect of release of intra-articular adhesions of arthrocentesis, we examined patients with closed lock of the temporomandibular joint by arthroscopy before and after irrigation. PATIENTS AND METHODS In 6 closed lock cases in which adhesions in the upper joint space were observed by arthroscopy before arthrocentesis, arthroscopic examination was performed again to confirm whether the adhesion was released after the procedure. Range of mouth opening and joint pain were examined to determine the clinical efficiency of the procedure. RESULTS Adhesion was not released by irrigation under low pressure but could be released by irrigation under high pressure. After irrigation under low and high pressure, the maximum mouth opening of the patients improved from 0 to 1 mm (average, 0.3 mm) and 2 to 6 mm (average, 3.7 mm), respectively. CONCLUSIONS The results indicate that arthrocentesis with sufficient pressure could be effective for closed lock cases with adhesions in the upper joint compartment.

Magnetic resonance imaging of the temporomandibular joint in patients with skeletal open bite and subjects with no dentofacial abnormalities

We aimed to record the prevalence of disc displacement and bony changes in the temporomandibular joints (TMJs) of patients with skeletal open bite. We studied 25 patients (50 joints) with skeletal open bite, 25 volunteers with no dentofacial abnormalities (50 joints), and 44 patients with closed lock and no dentofacial abnormalities (60 joints) using magnetic resonance imaging (MRI) of the TMJ. We found anterior disc displacement without reduction in 6 of the volunteers and in 24 of the patients with skeletal open bite (p=0.01). Among the 24 affected joints, 16 showed signs of bony change (67%) as did 24 of those with closed lock (40%). The fact that we found a significant difference in the incidence of anterior disc displacement without reduction and bony change between patients with skeletal open bite and control groups without deformities of the jaw indicates that these changes may be caused by skeletal open bite.

Natural course of acute closed lock of the temporomandibular joint.

To clarify the features of acute closed lock of the temporomandibular joint we compared the clinical condition of patients with acute and chronic closed lock, and investigated the natural history of acute closed lock. Forty patients with unilateral acute closed lock who were given no treatment and 40 patients with unilateral chronic closed lock were enrolled in the study. The duration of locking in those with acute closed lock ranged from 1 to 7 days, and that of those with chronic closed lock from 3 to 4 months. Differences between the groups in sex, age, maximum mouth opening, and joint pain were analysed. In those with acute closed lock who had had no treatment, maximum mouth opening and joint pain were measured at the initial visit and after 2, 4, 8, and 12 weeks. The number of dysfunctional joints was counted during each period and the natural course of the acute closed lock investigated. There were more women and older patients among those with chronic, than among those with acute, closed lock. We found no significant differences in the symptoms in the two groups. After 2 weeks of allowing the acute closed lock to take its natural course only 15 of the 40 had not resolved successfully, and after 12 weeks of taking its natural course only 2 had been unsuccessful. The number of joints that did not resolve successfully decreased progressively over time. Any treatment for acute closed lock should be easier and more effective than that of following its natural course.

Diagnostic accuracy of fat-saturated T2-weighted magnetic resonance imaging in the diagnosis of perforation of the articular disc of the temporomandibular joint

The accuracy of diagnosing a perforation of the articular disc of the temporomandibular joint (TMJ) is poor with conventional magnetic resonance imaging (MRI). We recently reported that a high signal-intensity area is usually found on fat-saturated T2-weighted MRI in the joint space between the articular disc and cartilage surface in joints in which the disc is displaced. A discrete image with an area of high signal-intensity in the middle of the articular disc may indicate perforation or rupture. The purpose of this study was to compare the accuracy of diagnosis of a perforated articular disc by fat-saturated T2-weighted MRI with that of arthroscopy. We studied 50 joints in 50 patients with closed lock of the TMJ who were examined with MRI and then by arthroscopy using an ultra-thin arthroscope. The agreement between the two methods of diagnosis was assessed using the κ coefficient. Evidence of perforation of the disc on MRI and arthroscopically was found in the same 7 joints; there was complete concordance (κ=1.00, p<0.001). The accuracy of diagnosis of perforation of a disc by fat-saturated MRI was therefore the same as that by arthroscopy using an ultra-thin arthroscope.

Access to the maxillary sinus using a bone flap with sinus mucosal and mucoperiosteal pedicles

We describe a procedure for removing lesions in the maxillary sinus using bone flaps with the sinus mucosa and mucoperiosteum. The surgical design is to construct a rectangular trapdoor using 3 consecutive bur-cuts, fracture the upper margin, and lift the bone lid upward. The osteotomy site on the inferior, medial, and lateral sides of the bone lid was exposed subperiosteally, but the mucoperiosteal and sinus mucosal attachments on the superior and central areas of the lid were maintained. Then, following fracture of the upper bone margin, the lid was lifted upward. In this way, the integrity of the mucoperiosteum and sinus mucosa was maintained. Advantages of the bone flap with soft tissue pedicles technique may be quick recovery and restored integrity of the sinus wall, with a low probability of infection because of vascularization of the bone lid. To realize this, a bone flap with both sinus mucosal and mucoperiosteal pedicles is more suitable.

Oral tumor resection and salivary duct relocation with an ultrasonic surgical aspirator.

We describe a procedure of oral tumor resection and salivary duct relocation with an ultrasonic surgical aspirator. After mucosal incision, resection of the underlying musculature was performed using an ultrasonic surgical aspirator. Using the apparatus, the salivary duct was easily exposed without damaging or cutting the duct. After identification of the salivary duct, salivary duct relocation was performed. After resection of the tumor, the artificial dermis was trimmed and sutured to the mucosal edges of the surgical defect. This method is a reliable and simple procedure that can be used to avoid postoperative complications such as salivary fistula or swelling of the gland.

Mandibular Coronoid Hyperplasia: A Case Report

Abstract A case of unilateral coronoid hyperplasia successfully treated by coronoidotomy with prolonged postoperative physiotherapy and reveal the postoperative radiographic changes between the sectioned part of the coronoid process and the mandibular ascending ramus is described. The patient was a 28-year-old man whose maximum mouth opening was 30 mm. A coronoidotomy of the left coronoid process was performed. Nine days after surgery, the patient started physiotherapy with a HU-OSr appliance. After coronoidotomy and physiotherapy, the maximum mouth opening had increased to 43 mm. Radiographic follow-up showed that the coronoid process apparently united with the mandibular ascending ramus, with moderate dislocation and inclination posteriorly. In the case presented, an intraoral coronoidotomy with postoperative physiotherapy for treatment of coronoid process hyperplasia allowed satisfactory and stable results in the correction of coronoid-malar interference.

Electromyographic Activity of the Jaw-closing Muscles Before and After Unilateral Coronoidectomy Performed on a Patient with Coronoid Hyperplasia: A Case Study

There have been few reports analyzing the activity of the jaw-closing muscles after coronoidectomy performed on a patient with coronoid hyperplasia. This paper presents a case study using electromyograms (EMGs) to evaluate the effects of unilateral coronoidectomy on the activity of masseter and temporal muscles. The patient was a 25-year-old male whose maximal range of jaw opening was 24 mm. After coronoidectomy of the left region, the range improved to 43 mm. EMGs were recorded in the center of the masseter muscles and the anterior part of the temporal muscles during gum chewing. Preoperatively, no abnormal EMG activity was observed. Eight months after surgery, increase in the ratio of the bilateral temporal muscle activity and a decrease in the ratio of the right masseter muscle activity were observed, and the proportion of activity of jaw closing muscles was out of the normal range. Eighteen months after surgery, there was slight return to the preoperative EMG activity. It was concluded that unilateral coronoidectomy could result in EMG changes of masseter and temporal muscles with a gradual return.

Factors related to the incidence of anterior disc displacement without reduction and bony changes of the temporomandibular joint in patients with anterior open bite

PurposeWe aimed to investigate factors related to the prevalence of anterior disc displacement without reduction (ADDwoR) and bony changes of the condylar head (bony changes) in the temporomandibular joints (TMJs) of patients with anterior open bite.MethodsSubjects are comprised of 36 preoperative patients (72 joints) with skeletal anterior open bite without facial asymmetry who had undergone orthognathic surgery at the Hokkaido University Hospital; magnetic resonance imaging of the TMJ and cephalometric analysis were performed before treatment. Logistic regression analysis was performed to clarify relationships among age, overbite, overjet, ANB angle, sella to nasion (SN) to mandibular plane angle (SN–MP angle), SN to ramus plane angle (GZN angle), gonial angle, and incidence of ADDwoR or bony changes in patients with anterior open bite.ResultsFifteen patients had bilateral ADDwoR, and five patients had unilateral ADDwoR; 17 patients had bilateral bony changes, and five patients had unilateral bony changes. SN–MP angle was greater in 20 patients with ADDwoR than that in 16 patients without ADDwoR (p < 0.05). GZN angle was greater in the 20 patients showing bony changes than that in the 16 patients without bony changes (p < 0.05).ConclusionIn terms of dentofacial morphology, SN–MP angle appears to be associated with the incidence of ADDwoR, and GZN angle appears to be associated with bony changes in the TMJ.

Repair of oral mucosal defects using artificial dermis: factors related to postoperative scar contracture

OBJECTIVE To clarify wound-healing situations with artificial dermis used for the repair of oral mucosal defects, we investigated the incidence of postoperative scar contracture and studied factors related to cicatrization. STUDY DESIGN Forty patients who underwent repair of oral mucosal defects using artificial dermis participated in this study. The degree of scar contracture was recorded 1 month after surgery. To study the factors related to cicatrization, patient characteristics of sex, age, excision region, fixation used, size of the graft, and number of days for silicon seat removal were examined. Logistic regression analysis was used for analysis of the relationship between cicatrization and patient characteristics. RESULTS One month after surgery, 70% of patients had no contracture, 22.5% of patients had moderate contracture, and 7.5% of patients had severe contracture. A significant correlation was found between cicatrization and the minimum diameter of the artificial dermis (P < .001). CONCLUSIONS Reducing the minimum diameter of the artificial dermis may contribute to a decrease in scar contracture.