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Biomedical subjects

Hidenori Mito

Publications and source records attributed to Hidenori Mito.

14 recordsLinked to original sources
PubMed2005

Primary squamous cell carcinoma of the lacrimal gland.

A 55-year-old Japanese woman presented with proptosis of the left eye that showed rapid progression with profound lid oedema and chemosis with pain. Magnetic resonance imaging and helical computed tomography demonstrated a large mass of the upper temporal orbit and extended bony destruction of the frontal and zygomatic bones. She was successfully treated with orbital exenteration. A diagnosis of primary squamous cell carcinoma of the lacrimal gland was made, which was confirmed by characteristic findings seen on histopathological examination.

Carcinoma, Squamous Cell↗
PubMed2004

Causes of undercorrection of medial palpebral fissures in blepharoptosis surgery.

PURPOSE: To ascertain the cause of undercorrection of the medial palpebral fissure in blepharoptosis surgery. METHODS: Twelve upper eyelids of 6 Asian cadavers, 4 male and 2 female (average age at death, 77.5 years), were studied. After exposing the levator muscle by removing bone of the superior orbital rim, the levator muscle and medial and lateral horns of aponeurosis were observed. RESULTS: The levator muscle was located in the anterolateral direction. Bifurcation angles of the medial horn were steeper than those of the lateral horn, but the lateral horn was wider than the medial horn (Student's t test; P < 0.0001). The inferior edge of the superior expansion of the aponeurosis extensively covered the lateral horn but only slightly covered the medial horn. Accordingly, most of the medial horn was constituted by only the thin structure of the middle and inferior expansion of the aponeurosis. CONCLUSIONS: Because the medial horn is structurally weaker and less dynamic than the lateral horn, the lateral side of the aponeurosis is pulled more strongly than the medial, often resulting in medial undercorrection in blepharoptosis surgery. To prevent this, the medial part should be fixed more widely than the lateral.

Aged↗
PubMedDate not supplied

Magnetic resonance imaging of pre- and postoperative lower eyelid states in involutional entropion.

PURPOSE: To disclose pre- and postoperative lower eyelid gradients in involutional entropion using sagittal magnetic resonance imaging (MRI). METHODS: Three female patients, average age 82 (two right eyes and one left), were operated on for involutional entropion by the Jones procedure. Before and after the surgery, the lower eyelid gradient was evaluated by MRI and photography. RESULTS: Preoperatively, each lower eyelid presented anterior protrusion, and the retractor was apart from the globe. Postoperatively, no anterior protrusion was observed, and the retractor was pulled posteroinferiorly and located parallel to the globe. CONCLUSIONS: The MRI visualization of pre- and postoperative changes of gradient in the lower involutional entropion supports surgical reconstruction.

Aged↗
PubMedDate not supplied

The medial canthal tendon is composed of anterior and posterior lobes in Japanese eyes and fixes the eyelid complementarily with Horner's muscle.

PURPOSE: To report that the medial canthal tendon (MCT) is not simply the aggregate of the orbicularis oculi muscle (OOM) and its tendon. METHODS: Twenty eyelids of 10 cadavers were used. The cadavers, seven male and three female, were all Japanese, with an average age of death of 76.2 years. The relationship between the MCT and the OOM, and between the tarsus and Horner's muscle were investigated. Histological findings were obtained with hematoxylin and eosin staining. RESULTS: The MCT was structured with an anterior lobe, the tendon from the tarsal area of the OOM, and a posterior lobe, the muscle-tendon transition area in the orbital area of the OOM. The nasal aspect of the tarsus was fixed by Horner's muscle. CONCLUSIONS: The MCT and Horner's muscle are located in an important area of the eyelid; therefore, it is essential to understand their precise anatomy.

Aged↗
PubMedDate not supplied

Incarceration of the inferior oblique muscle branch of the oculomotor nerve in two cases of orbital floor trapdoor fracture.

BACKGROUND: Incarceration of the inferior oblique muscle (IO) branch of the oculomotor nerve may occur in cases of orbital floor trapdoor fracture. CASES: Two orbital floor trapdoor fracture cases, with lesions located just outside of the inferior rectus muscle but without its incarceration, were examined pre- and postoperatively for visual acuity, intraocular details, the nine diagnostic ocular positions of gaze, binocular single vision field with the Hess chart, and by computed tomography (CT). One case was also examined by magnetic resonance imaging (MRI; T1-weighted images). A forced duction test was conducted intraoperatively. OBSERVATIONS: Each case presented good visual acuity and neither globe showed any injury. Motility disturbance of the IO was shown in each case by binocular single vision field testing and the Hess chart. The possibility of the incarceration of the IO branch of the oculomotor nerve, which runs from the incarcerated lesion to the superior belly of the IO, in an orbital floor trapdoor fracture was shown on CT and MRI. Intraoperative forced duction testing revealed a restriction due to the incarceration of the connective tissue septa. CONCLUSIONS: As inferred from the CT and MRI analyses conducted in this study, IO palsy may be one of the causes of ocular motility disturbance of the IO in an orbital floor trapdoor fracture, in addition to the ocular motility disturbance due to the connective tissue septa.

Adult↗
PubMedDate not supplied

Intraoperative quantification using finger force for involutional blepharoptosis without postoperative lagophthalmos.

PURPOSE: To report intraoperative quantification using finger force for involutional blepharoptosis, which helps in the prevention of postoperative lagophthalmos. METHODS: We carried out levator resection on 20 involutional blepharoptic eyelids. Fissure height was examined intraoperatively to evaluate the extent of resection. If a patient presented more than 3 mm of lagophthalmos in voluntary eyelid closure but could fully open the eye, we forcibly closed the eyelid, using a finger, after voluntary eyelid closure. If more than 3 mm of lagophthalmos was still observed after forced eyelid closure, we corrected eyelid tension until lagophthalmos became less than 2 mm. RESULTS: Six of the ten patients (20 eyelids) presented with full eyelid opening but more than 3 mm of lagophthalmos in voluntary eyelid closure. After the upper eyelids were forcibly lowered, all six eyelids showed less than 2 mm of lagophthalmos. There were no cases of lagophthalmos 1 month postoperatively. CONCLUSIONS: Additional finger force makes precise quantification of blepharoptosis surgery possible and prevents postoperative lagophthalmos.

Aged↗