Biomedical subjects

N Kiya

Publications and source records attributed to N Kiya.

9 recordsLinked to original sources

PubMed2001

Monitoring of facial evoked EMG for hemifacial spasm: a critical analysis of its prognostic value.

Microvascular decompression (MVD) has come to stay as an effective way of treating hemifacial spasm. But it remains to be seen how much each of the electrophysiological monitoring techniques (intra-operative) are contributing to its increased efficacy. Their role as indicators for re-exploration or recurrence is to be evaluated with more studies. We have used the lateral spread response in those patients who had distinctly abnormal recording on the ipsilateral side, studied the intra-operative changes during MVD and correlated with the outcome of surgery. 38 patients operated for HFS, were selected for intra-operative monitoring of abnormal muscle responses. In 17 patients, there was persistence of abnormal muscle responses in the immediate postoperative period and only 6 of them had mild HFS. Two of 21 patients who had disappearance of abnormal responses had persistent mild HFS; but in all cases, the HFS disappeared within 3 months. So we found that the intra-operative recording was really not reliable in predicting the immediate postoperative outcome. However the outcome at 3 months suggested that waiting for some time before re-exploration is a better option, especially if the HFS had become mild.

Adult↗

PubMed2000

Minimally invasive surgical exposure of the extreme high cervical internal carotid artery: anatomical study.

The purpose of this study is to investigate a minimally invasive access to a high cervical lesion involving the internal carotid artery. Using 13 fixed cadaveric preparations, we sought to design a surgical approach that would cause minimal involvement of the surrounding structures and maximal exposure to the extreme high cervical area. This technique preserves the function and integrity of the mandible, sternocleidomastoid, posterior belly of digastric and styloid process muscles. The method uses retraction and mobilisation of those muscles, as well as decompression of the facial from the stylomastoid foramen. The internal carotid artery is exposed up to the entry point into the carotid canal. The cranial nerves IX, X, XI and XII are kept in sight up to the jugular foramen. This approach creates a wide corridor into the deep high cervical and inferior cranial base area and can be utilised for high cervical carotid lesions and tumours related to the artery.

Aged↗

PubMed2000

Neuroendoscopy in microvascular decompression for trigeminal neuralgia and hemifacial spasm: technical note.

Miocrovascular decompression is an effective treatment for trigeminal neuralgia (TN) and hemifacial spasm (HFS). A complete cure cannot be obtained, and additional adjuncts for extended use of endoscopy are needed. The use of an endoscope combined with the operating microscope can enhance the surgeon's ability to view deep structures during operation. We study the application of combined microsurgical and endoscopic techniques in 21 cases of HFS and 12 cases of TN. With these techniques the surgeon can explore the ventral aspect of the brainstem and cranial nerves without further retraction, can see the groove caused by compression of the offending artery, and can confirm the proper position of the prosthesis after attachment to the dura by fibrin glue. In HFS the most common offending vessels in 75% of cases were the posterior inferior cerebellar artery (PICA) and anterior inferior cerebellar artery (AICA) and in 25% of cases the vertebral artery (VA). In trigeminal neuralgia the offending vessel in 60% of cases was the superior cerebellar artery (SCA), and in 40% of cases the AICA. The overall success rate was 97% with minimal morbidity 3% (facial palsy) and no mortality. The aim of this work is to study advantages and disadvantages of using endoscopy during microvascular decompression for TN and HFS.

Brain Stem↗

PubMed1997

Migration activity of microglia and macrophages into rat brain.

We examined the entry of intra-arterially injected microglia and macrophages into the brain using a rat muscle graft model to compare their respective abilities to invade the brain parenchyma. Isolated microglia without any activation treatment entered into the brain with or without the muscle graft, while macrophages activated by phorbol 12-myristate-13-acetate (PMA) entered the brain only in the presence of the muscle graft. These results suggest that microglia have a higher affinity for the brain than macrophages.

Animals↗

PubMed1997

Computer navigational microscope for minimally invasive neurosurgery.

Frameless navigational devices have recently undergone an evoluation to the point where they are being used more efficiently in the clinical setting. Most of the present-day systems utilize some form of mechanical arm to correlate registered points in space to the computer terminal. However, the articulated arm can be cumbersome and is an additional obstacle in the surgical field. To avoid this problem some groups have elected to transmit registered points and probe position using ultrasound or electromagnetic fields. However, in using magnetic fields, ferromagnetic metals can interfere with accuracy. On the other hand with ultrasonic digitizers accuracy is dependent on variable factors such as humidity, local temperature, and positioning of the emitters. In response to some of these difficulties inherent with frameless stereotaxy, the MKM system was developed. Essentially it is an optically based system in which the CT and/or MRI data are superimposed three-dimensionally onto the surgical field as seen through the microscope using head-up display technology. It requires no opto-kinetic link such as a headframe, mechanical arm, ultrasonic, and magnetic field. We have used the MKM microscope system to guide 18 neurosurgical procedures. This report illustrates the advantages of this system when combined with keyhole surgery to provide accurate excision of brain lesions while preserving normal tissue.

Adolescent↗

PubMed1996

Synthesized surface anatomy scanning (SSAS) for surgical planning of brain metastasis at the sensorimotor region: initial experience with 5 patients.

Surface anatomy scanning (SAS) is a powerful technique that uses T2-weighted magnetic resonance images (MRI) to visualize brain surface structures, and to precisely localize subcortical lesions. To overcome technical limitations of this method, synthesized SAS (SSAS) superimposes MR angiography (MRA) data on the SAS images. We describe our initial experience with surgical planning for the resection of metastases at the sensorimotor region in 5 patients using SSAS. Neurological deficits were assessed before and after surgical resection. Although 4 of 5 patients had mild to severe neurological deficits before surgery, three became symptom-free and no patient had an increased deficit after surgery. Our results undoubtedly provide palliative surgery for sensorimotor metastases. As SSAS is non-invasive and requires a short scanning time, this method could become a useful technique for the routine pre-operative simulation for surgery on brain surface lesions such as sensorimotor metastases.

Adenocarcinoma↗

PubMed1995

Usefulness of simulation of surgical approaches to cerebral aneurysms by helical scanning CT (HES-CT).

Using multiplanar reconstruction (MPR) CT imaging method, virtual views of various surgical approaches were compared preoperatively. With this technique, not only virtual surgical views of aneurysms and related vasculature, but also surgical views after virtual resection of skull base bone to a desirable extent are freely available. We operated four aneurysm cases after comparing various surgical approaches by this imaging method. It was found that these preoperative simulated images were very useful at surgery of complicated aneurysm cases.

Adult↗

PubMed1995

Tolosa-Hunt syndrome with unusual clinical courses--two case reports.

Two cases of Tolosa-Hunt syndrome with unusual clinical courses are described. The clinical onset of the first patient was typical, but was unresponsive to steroid hormone treatment. The symptoms resolved spontaneously after 1 year. Computed tomography (CT) and magnetic resonance (MR) imaging revealed enlargement of the affected cavernous sinus, which did not change after the symptoms resolved. The clinical presentation in the second patient included marked pupillary dilatation, a sign which is absent in the classical criteria. CT showed no abnormal findings, but MR imaging revealed a mass located in the medial side of the cavernous sinus extending to the lateral wall, which might have caused the pupillary dilatation. After steroid therapy the symptoms disappeared and MR imaging showed remarkable reduction of the mass in the cavernous sinus. Tolosa-Hunt syndrome usually responds promptly to steroid therapy and rarely manifests marked pupillary dilatation. Such variation in presentation adds to the difficulties in diagnosis and treatment of this disease of unknown etiology.

Adult↗

PubMed1995

Intracerebral infiltration by monoclonal plasmacytoid cells in Waldenstrom's macroglobulinemia--case report.

A 68-year-old female presented with Waldenstrom's macroglobulinemia with infiltration into the cerebral parenchyma manifesting as increased confusion, memory loss, and disorientation. She had a past history of Waldenstrom's macroglobulinemia treated 3 years before. Magnetic resonance imaging showed a high intensity area on T2-weighted images in the left frontal lobe extending to the corpus callosum which was well enhanced by gadolinium-diethylenetriaminepenta-acetic acid. Direct infiltration of neoplastic cells was confirmed by biopsy. Immunohistochemical examination showed that mature plasmacytoid cells in the cerebral parenchyma were immunoglobulin M and lambda light chain antigen positive, but immature lymphocytes in Virchow-Robin space were negative. Monoclonal proliferation was confirmed by southern blot analysis. She became symptom free and the size of the lesion was dramatically reduced after 40 Gy irradiation. She showed no evidence of recurrence 3 years after irradiation. As no effective chemotherapy regimen for Bing-Neel syndrome has been established, irradiation is worth considering when neuroimaging suggests intracranial infiltration of neoplastic cells.

Aged↗