Biomedical subjects

Hiroya Yamaguchi

Publications and source records attributed to Hiroya Yamaguchi.

9 recordsLinked to original sources

PubMed2006

Three-dimensional laryngeal model for planning of laryngeal framework surgery.

CONCLUSION: The three-dimensional prototype model was useful for planning of laryngeal framework surgery. OBJECTIVE: To discuss the usefulness of a three-dimensional laryngeal model for laryngeal framework surgery. MATERIALS AND METHODS: A three-dimensional laryngeal model was created based on the postoperative helical computed tomography (CT) data of the larynx (case 1) which underwent lateral cricoarytenoid muscle (LCA) pull surgery. LCA pull surgery is a kind of arytenoid adduction for unilateral vocal cord paralysis. A three-dimensional model of case 1 larynx was prototyped using a selective laser sintering method. In case 1, the patient's voice did not improve after LCA pull surgery. The three-dimensional model revealed that the original surgical procedure was not appropriate to obtain optimal arytenoid adduction. According to the analysis of this three-dimensional model, we changed the surgical approach and performed this new refined LCA pull surgery on another patient with unilateral vocal cord paralysis (case 2). RESULTS: We were able to pull LCA precisely in case 2. Three-dimensional CT of case 2 after refined LCA pull surgery allowed the correct pulling of LCA and complete adduction of arytenoid. The postoperative voice improved remarkably.

Aged↗

PubMed2005

The relationship between esophagoscopic findings and total acid reflux time below pH 4 and pH 5 in the upper esophagus in patients with laryngopharyngeal reflux disease (LPRD).

OBJECTIVE: : To investigate the relationship between esophagoscopic findings and total acid reflux time in the upper esophagus in the patients of laryngopharyngeal reflux disease (LPRD), and to evaluate whether pH<5 holding time is appropriate for diagnosing LPRD. METHOD: : Esophagoscopy and 24-h pH monitoring in the upper esophagus were performed in 29 patients suspected of LPRD and 19 healthy volunteers participated as controls. The total acid reflux times below pH 4 and 5 in the upper esophagus were compared between the LPRD group and the controls. The LPRD group was divided into LPRD with reflux esophagitis (RE) and LPRD without RE, and the total acid reflux times below pH 4 and 5 of these two groups were compared. RESULTS: : Eight of the 29 (27.6%) LPRD patients had reflux esophagitis. The LPRD group showed a significantly longer acid reflux time than the control group at pH below 5 (P=0.009) but not at pH below 4 (P=0.48). The LPRD with RE had significantly longer acid reflux times below both pH 4 and 5 in the upper esophagus compared to those of the LPRD without RE. The P values using a cut-off value of pH 5 were smaller than that of pH 4 in all statistical results. CONCLUSION: : The LPRD patients showed significantly longer acid reflux time in the upper esophagus than the control group. In the LPRD group, the LPRD with RE patients had more frequent acid exposure in the upper esophagus than the LPRD without RE. A pH level of 5 could be appropriate as a cutoff level for the diagnosis of LPRD in upper esophagus pH monitoring.

Case-Control Studies↗

PubMed2005

Direct pull of lateral cricoarytenoid muscle for unilateral vocal cord paralysis.

CONCLUSION: Lateral cricoarytenoid muscle-pull surgery (LCA pull) is a safe and effective method for the treatment of unilateral vocal cord paralysis. OBJECTIVE: To evaluate the results of an improved method of LCA pull for unilateral vocal cord paralysis. MATERIAL AND METHODS: Thirteen patients with unilateral vocal cord paralysis underwent LCA pull between April 2003 and January 2004. A small window was made in the posterior lower part of the thyroid cartilage and 2-3 mm in a cranial direction to the lower edge of the thyroid cartilage. The inner perichondrium was carefully removed to expose the LCA muscle. A 4-0 nylon suture placed through the LCA muscle was pulled to adduct the arytenoid and was tied to the anterior lower part of the thyroid cartilage. All cases were treated by LCA pull alone. In all cases, the maximum phonation time was measured and an auditory evaluation was performed using the grade, roughness, breathiness, asthenia and strain scale. The airflow rate was measured in five cases. RESULTS: Vocal improvement was obtained in 11/13 cases (85%). One of the unimproved cases had cricoarytenoid joint ankylosis. No complications were observed.

Adult↗

PubMed2004

Rapid prototyping of temporal bone for surgical training and medical education.

OBJECTIVE: The skills of ear surgery are best developed by dissecting a temporal bone. However, only a limited number of trainees can be afforded this opportunity because of the scarcity of available bones. The aim of this study was to investigate the validity of a prototype temporal bone model for surgical training and education. MATERIAL AND METHODS: A simulated 3D model of a human temporal bone was made using a selective laser sintering method. The powder layers were laser-fused based on detailed CT data and accumulated to create a 3D structure. Conventional surgical instruments were used to dissect the model under a microscope. RESULTS: The model was as hard as real bone and surface structures were accurately reproduced. The model could be shaved using a surgical drill, burr and suction irrigator in the same way as a real bone. The malleus and incus were reproduced. The semicircular canals and the oval and round window niches were identified. Cavity structures, such as the semicircular canal, vestibule, antrum and air cells, were filled with powder which had to be removed using a pick and suction irrigator during dissection. A magnified model was useful for educating medical students. CONCLUSION: This prototype 3D model made using selective laser sintering serves as a good educational tool for middle ear surgery.

Humans↗

PubMed2004

Rapidly prototyped temporal bone model for otological education.

The anatomy of the temporal bone is extremely complicated. If a three-dimensional model could be simulated, it would greatly contribute to the stereoscopic understanding of anatomy and surgery. A simulated three-dimensional model of a human temporal bone was prototyped using the selective laser sintering method. The model could be shaved using a surgical drill in the same way as in real surgery. A magnified model was particularly useful for the instruction of anatomy and surgery. When a translucent area was selected, a bony labyrinth could be created together with an internal auditory meatus and facial nerve, which also contributed to the easy understanding of the inner ear structure. The three-dimensional prototyped model using selective laser sintering serves as a good educational material for middle ear anatomy and surgery.

Humans↗

PubMed2004

[Rapid prototyping of the larynx for laryngeal frame work surgery].

A detailed understanding of the three-dimensional (3D) structure of the larynx is important for determining appropriate methods and approaches for laryngeal frame work surgery. In this study, a 3D laryngeal model was constructed based on postoperative helical CT data obtained after lateral cricoarytenoid muscle (LCA) pull surgery (Iwamura) for the treatment of unilateral vocal fold paralysis. The anatomical configurations of the arytenoid cartilages and the optimal approaches for laryngeal frame work surgery were then examined. A 3D model of the human larynx was prototyped using a selective laser sintering method. A compound powder of plastic nylon and an inorganic substance (glass beads) was used as the raw material. The cricoid cartilage and the arytenoid cartilages were prototyped, and the configurations of the arytenoid cartilages were evaluated. The results were similar to those of previous reports. The arytenoid cartilage of the unaffected side moved downward while adducting, and the vocal process moved inwards and downwards. On the other hand, the paralyzed arytenoid cartilage moved neither inward nor downward, and the vocal process was fixed at an outer and upper position. Next, the thyroid cartilage was added to the model to determine the optimal location of the window in the thyroid cartilage for the LCA pull surgery. The window after the first surgery was largened using a surgical drill. The 3D prototype model was useful for understanding the complex configurations of the laryngeal anatomy, and to determine the optimal approaches for laryngeal frame work surgery, etc.

Arytenoid Cartilage↗

PubMed2003

[Multi-center trial of gemcitabine for 49 patients with advanced pancreatic cancer].

Forty-nine patients with unresectable pancreatic cancer (stage IV disease) received gemcitabine in a multi-center trial in the Fukuoka pancreatic cancer chemotherapy group, Japan. No complete remissions, 5 partial remissions (10%) and 25 no changes (51%) were obtained. Gemcitabine could maintain QOL. Main toxicities were hematologic, especially neutropenia. Neutropenia tended to appear in early administration. Non-hematologic toxicities were anorexia, nausea/vomiting, and skin rash. The mean overall survival period was 7.5 months. Carcinomatous ascites and/or pleural effusion resulted in a poor prognosis (average survival 3.1 months). Gemcitabine could be given without severe toxicities in outpatient clinics. These results suggested that gemcitabine is currently a first-line therapeutic agent for advanced pancreatic cancer.

Adult↗

PubMed2002

Globus sensation caused by gastroesophageal reflux disease.

OBJECTIVES: This study was designed to examine whether or not gastro esophageal reflux disease (GERD) is implicated in globus sensation. METHODS: The subjects were 25 patients (16 men/9 women; mean age: 51, range 25-69 years) complaining of globus sensation with one or more of four laryngeal findings suspected of having GERD, such as pooling of saliva, erythema of posterior one-third of larynx, inter-arytenoids edema, and granuloma. All 25 patients were administrated a proton pump inhibitor (PPI) for a period of 8 weeks. All were given esophageal endoscopies, laryngoscopes, and questionnaire before and after PPI dosing. The questionnaire survey was conducted to investigate changes in globus sensation and three symptoms specific to GERD including heartburn, regurgitation, and belching. Subjective symptoms were totalled by the over all scores of the three subjective symptoms which served as an index of severity of GERD. RESULTS: Fifty-two percent (13/25) of patients had reflux esophagitis. The esophagitis were improved after PPI administration except one case. The incidences of GERD symptoms were high (heart burn 68% (17/25), belching 49% (10/25) and regurgitation 76% (19/25)), and most of these symptoms ameliorated by PPI administration. The laryngeal findings were improved in all patients. Subjective symptoms were improved in 68% (17/25) of globus patients. The improvement rate of total score (before PPI dosing/after PPI dosing) was compared between the two groups: one with improved globus sensation (17 patients) and the other without (8 patients). The improvement rate was significantly higher in the group with improved globus sensation (P<0.05). This means that globus sensation improved because of the improvement in GERD. CONCLUSION: GERD is therefore concluded to be an inducing factor of globus sensation.

Adult↗

PubMedDate not supplied

A comparison of voice quality ratings made by Japanese and American listeners using the GRBAS scale.

The GRBAS scale is a widely used method for perceptual evaluation of voice quality. Two linguistically diverse groups of listeners (Japanese and American) rated 35 voice samples using the GRBAS scale. The ratings obtained from the two groups were compared to determine if the different linguistic background affected the use of the GRBAS scale. Results show that there are no significant differences between the Japanese and American listeners in the use of the Grade, Roughness and Breathiness scales. Ratings on the Asthenia and Strain scales, however, were different between the two groups of listeners. Despite these discrepancies, the GRBAS scale may be an excellent tool for perceptual evaluation of voice quality by linguistically diverse groups.

Adolescent↗