Biomedical subjects

Yukinari Kakizawa

Publications and source records attributed to Yukinari Kakizawa.

13 recordsLinked to original sources

PubMed2006

Transient cerebellar mutism caused by bilateral damage to the dentate nuclei after the second posterior fossa surgery. Case report.

The authors report on the case of a 6-year-old boy who underwent resection of a midline cerebellar tumor. The boy was able to speak fluently after the operation. Magnetic resonance (MR) imaging showed that the right dentate nucleus had been partially removed along with the tumor, but that the left dentate nucleus remained with the residual tumor. A second operation was performed to remove the residue, after which the child suffered mutism. Three weeks post-surgery, he could only communicate through gestures. He started speaking I week later and regained normal speech 2 months after the operation. Final MR imaging revealed gross-total removal of the tumor and dentate nucleus on the injured left side. The cerebellar mutism was considered to have been caused by bilateral damage to the dentate nuclei and not by unilateral damage.

Cerebellar Neoplasms↗

PubMed2005

Odontoid compression of the brainstem without basilar impression-- "odontoid invagination".

We report five patients with odontoid invagination, in which the odontoid process bulges upward into the foramen magnum and compresses the brainstem without deformity of the occipital bone. Two patients had a craniovertebral abnormality associated with Chiari malformation without instability of the craniovertebral junction (stable odontoid invagination). The other three patients had dislocation of the craniovertebral junction due to iatrogenic destruction of the occipital condyle, rheumatoid arthritis or an anomaly of C2 (unstable odontoid invagination). Patients with stable odontoid invagination underwent a transoral odontoidectomy followed by occipitocervical fixation. Those with unstable odontoid invagination underwent cervical traction followed by posterior fixation in reducible cases, while in irreducible cases odontoidectomy with subsequent occipitocervical fixation was performed. Decompression of the neuraxis together with symptomatic improvement was achieved in all patients and none became unstable or developed new symptoms during follow-up ranging from 3 to 15 years.

Adult↗

PubMed2003

Simple cervical spine traction using a halo vest apparatus: technical note.

BACKGROUND: A halo vest apparatus, commonly used for external immobilization and protection of the cervical spine, offers several advantages. We present here a simple, accurate, easy, and safe cervical traction technique using a halo vest apparatus. METHODS: The distinguishing feature of our technique is that, after application of a halo vest apparatus, the halo crown is distracted gradually and stepwise by turning the bilateral screw bolts that hold the halo crown over a period of one to several weeks. After each of these steps, care must be taken to check neurologic, radiologic, and skin conditions, as well as cranial pin tightening. CONCLUSIONS: This distance control technique can provide a strong and accurate traction force by simply turning the bolts without the risk of overdistraction or the need for bed rest, and can be used in conjunction with radiologic examination and transportation of patients, even those unable to walk. The Sugita head fixation system constitutes a safe and easy way to facilitate surgical management after correction of cervical dislocation.

Cervical Vertebrae↗

PubMed2003

Aneurysm at the posterior inferior cerebellar artery of extradural origin for preoperative evaluation of safe clipping: case report and review of the literature.

BACKGROUND: As far as we know, 6 cases of extracranial (including craniocervical junction) intradural aneurysms of the posterior inferior cerebellar artery have been previously reported. However, preoperative detailed evaluation of the origin site and a course of the posterior inferior cerebellar artery by means of angiography were not reported in previous papers. CASE DESCRIPTION: We report a rare case of aneurysm of the posterior inferior cerebellar artery, which originated extradurally from the right vertebral artery. A 69-year-old woman experienced a sudden headache 16 years ago and a computed tomography scan showed a subarachnoid hemorrhage around the midbrain. Four-vessel cerebral angiography, however, failed to disclose a source of the hemorrhage. Magnetic resonance angiography incidentally revealed an aneurysm at the craniocervical junction 16 years after the subarachnoid hemorrhage. The aneurysm was exposed and clipped via a suboccipital route. At surgery, it was of no use to apply a temporary clip on the intradural segment of the vertebral artery, because the posterior inferior cerebellar artery was found to enter the intradural space separately from the vertebral artery. The blood flow to such an aneurysm cannot be stopped with this procedure. CONCLUSIONS: Careful neuroimaging study is essential for the accurate diagnosis and successful treatment of such a rare aneurysm.

Aged↗

PubMed2003

Protective dural flap for bone drilling at the paraclinoid region and porus acusticus--technical note.

A new method was developed to avoid the risk of injury to the cranial nerves and vessels during intradural bone resection at the paraclinoid region and porus acusticus. The semicircular dural flap is pulled out with a thread over the anterior clinoid process or the porus acusticus. The flap is extended over the underlying structures with a tapered spatula to create adequate space for drilling the bone. The site for drilling was adequately exposed and bone was drilled away smoothly without damaging the underlying vessels and nerves in 10 patients with paraclinoid aneurysms and in seven patients with vestibular schwannomas. This "protective dural flap" method provides wide exposure for drilling, protects the underlying structures, and allows quick inspection during bone resection.

Brain Diseases↗

PubMed2003

Growth pattern and rate in residual nonfunctioning pituitary adenomas: correlations among tumor volume doubling time, patient age, and MIB-1 index.

OBJECT: Surgical cure can be achieved in pituitary adenomas when they are completely removed. It is controversial whether postoperative radiation therapy should be given to prevent recurrence, and whether an early reoperation should be performed for residual adenomas, because we have little information about the natural history of postoperative residual adenomas. METHODS: The residual tumor volume was serially measured in 40 nonfunctioning pituitary adenomas (NFPAs) and the tumor volume doubling time (TVDT) was calculated. Correlations between the patients' age, tumor volume, log TVDT, and MIB-1 index were examined. Other factors including the patient's sex, cavernous sinus (CS) invasion by the tumor, or presence of an intratumoral cyst were analyzed to assess their influence on the TVDT. Values are expressed as the means +/- standard deviations. Thirty-eight adenomas increased in volume and two decreased during a follow-up period ranging from 4 to 141 months (mean 52.5 months). Exponentially linear tumor growth was observed in the 38 growing adenomas regardless of the residual tumor volume, with the TVDT ranging from 506 to 5378 days (mean 1836 days). The patients' age was 57.1 +/- 15.7 years (range 15-79 years), the tumor volume at the beginning of the magnetic resonance imaging observation period was 2.5 +/- 2.2 cm3 (range 0.07-14.5 cm3), and the MIB-1 index was 0.73 +/- 0.68% (range 0.1-2.9%). There was a correlation between the log TVDT and patient age (R = 0.73), an inverse correlation between the log TVDT and MIB-1 index (r = -0.49), and an inverse correlation between the MIB-1 index and patient age (r = -0.61). A significant difference (p = 0.0001) was noted between the TVDT (1,106 days) in the 19 patients younger than 61 years of age and the TVDT (2566 days) in the 19 patients who were 61 years of age or older. There was also a significant difference (p = 0.0002) between the age (50.8 +/- 15.3 years) of the patients with rapidly growing tumors (TVDT < 1,836 days, 24 patients) and the age (69.1 +/- 7.6 years) of the patients with slowly growing tumors (TVDT> 1836 days, 14 patients). Other factors including the patients' sex, CS invasion, and intratumoral cyst formation did not affect the TVDT of residual NFPAs. CONCLUSIONS: The tumor growth rate of residual NFPAs is strongly influenced by the patient's age. The TVDT in elderly patients is much longer than that previously reported. Treatment strategies that take into consideration the natural history of residual adenomas should be established especially in the elderly population.

Adenoma↗

PubMed2003

"Real" three-dimensional constructive interference in steady-state imaging to discern microneurosurgical anatomy. Technical note.

Three-dimensional (3D) neuroimages are generally considered useful for neurosurgical practice. Nevertheless, neuroimaging modalities such as 3D digital subtraction angiography and 3D computerized tomography angiography are still insufficient because the resulting images fail to delineate neural structures. Complex neurosurgical procedures are mostly performed in the cerebrospinal fluid (CSF) space of the basal cistern, where vessels and neural structures are present along with the lesion. The magnetic resonance (MR) imaging-derived 3D constructive interference in steady-state (CISS) imaging displays the margin between the CSF and neural structures, vessels, and dura mater in detail, in a two-dimensional fashion. The authors know that volume-rendered 3D CISS images would be more useful for surgery than conventional ones. Although the usefulness of "virtual MR image endoscopy" was reported previously, the endoscopic view is different from the operative field because of the perspective being emphasized. Therefore, to simulate surgical views, the authors made 3D neuroimages from a 3D CISS MR sequence by using an advanced computer workstation. After generating volume images, a cutting method was used in the desired plane to visualize the lesion with reference to a multiplanar reformatted image. The authors call these "real" 3D CISS images, and they are more comparable to the operative field. This newly developed method of producing a real 3D CISS image was used in 30 cases and contributed to the understanding of the relationship between a lesion and surrounding structures before attempting neurosurgical procedures, with minimal invasiveness to the patient.

Basilar Artery↗

PubMed2003

Clinical application of robotic telemanipulation system in neurosurgery. Case report.

The NeuRobot is a telecontrolled microscopic micromanipulator system designed for neurosurgical procedures. The unit houses a three-dimensional endoscope and three robot arms that the surgeon operates without direct contact with the patient. The authors have successfully performed robotics-assisted neurosurgical procedures by using the NeuRobot in a 54-year-old man who had a recurrent atypical meningioma. Following the usual preparation of craniotomy and opening of the dura mater, a portion of the tumor was removed using the NeuRobot with the aid of microscopic observation. No complication related to the use of the NeuRobot was encountered and the patient's postoperative course was uneventful. Although various kinds of robots have been developed for use in neurosurgery in recent years, a robotic telemanipulation system capable of performing several surgical tasks has not previously been introduced to clinical neurosurgery. This is the first case report in which neurosurgical manipulation by a robotics system is described.

Humans↗

PubMed2002

Chronic subdural hematoma after transsphenoidal surgery.

Chronic subdural haematoma has not been reported as a complication of transsphenoidal surgery. We present a case of pituitary adenoma which was gross-totally removed by transsphenoidal surgery with the enlarged sellar opening. Postoperative serial imaging showed massive air accumulation in both frontal subdural spaces followed by subdural fluid collection and subsequent chronic subdural haematomas 2 months later. We conclude that close follow up imaging study is required to avoid overlooking chronic subdural haematoma when massive air is introduced into the subdural space by the transsphenoidal surgery.

Adenoma↗

PubMed2002

NeuRobot: telecontrolled micromanipulator system for minimally invasive microneurosurgery-preliminary results.

OBJECTIVE: Microneurosurgery can be performed less invasively with the recent advances in neuronavigation and neuroendoscopy. For even less invasive microneurosurgery, we have developed a telecontrolled micromanipulator system. METHODS: The NeuRobot telecontrolled micromanipulator system was developed. With the use of this system, surgical simulations were performed with a human cadaveric head. RESULTS: The system consists of four main parts, i.e., a micromanipulator (slave manipulator), a manipulator-supporting device, an operation-input device (master manipulator), and a three-dimensional display monitor. Three 1-mm forceps and a three-dimensional endoscope, which could be remotely controlled with three degrees of freedom (rotation, neck swinging, and forward/backward motion), were installed in the slave manipulator. All surgical procedures were accurately performed with this system. CONCLUSION: The use of telecontrolled manipulator systems in neurosurgery is very promising, and we are convinced that this system will facilitate more accurate, less invasive microneurosurgery. The details of the NeuRobot system and preliminary results are presented.

Cadaver↗

PubMed2002

Three-dimensional contrast medium-enhanced computed tomographic cisternography for preoperative evaluation of surgical anatomy of intradural paraclinoid aneurysms of the internal carotid artery: technical note.

OBJECTIVE AND IMPORTANCE: Precise preoperative evaluation is especially important when internal carotid artery aneurysms in the paraclinoid region are clipped, because these vascular structures are located in close proximity to various important structures such as the optic nerve and anterior clinoid process. We report a new method for "simultaneously" describing the interrelationships among the aneurysm, internal carotid artery, optic nerve, and bony structures with three-dimensional contrast medium-enhanced computed tomographic (3-D CMECT) cisternography. METHODS: Informed consent was obtained from the patient. An 8-ml injection of iotrolan (Isovist; Schering, Berlin, Germany) (240 mg I/ml) was administered into the lumbar intrathecal space. A computed tomographic scan of the head was obtained 2 hours later with a multislice Asteion computed tomographic scanner (Toshiba, Inc., Tokyo, Japan). An Alatoview workstation (Silicon Graphics, Mountain View, CA) was used to reconstruct the three-dimensional images. RESULTS: These images, as generated by 3-D CMECT cisternography, were found to accurately demonstrate the interrelationships of the internal carotid artery, aneurysm, and surrounding structures preoperatively. The findings obtained from these images proved to be quite similar to the intraoperative findings. 3-D CMECT cisternography clarified whether the paraclinoid aneurysm was intradural or extradural. CONCLUSION: 3-D CMECT cisternography was found to provide a useful means for preoperative evaluation of lesions in the paraclinoid area.

Aged↗

PubMed2002

Endoscopic telerobotics for neurosurgery: preliminary study for optimal distance between an object lens and a target.

To overcome limited maneuverability and procedures in the endoscopic neurosurgery, and to utilize its maximum potential ability, the HUMAN (hyper-utility mechatronic assistant) system has been developed. The system has a rigid three-dimensional endoscope with built-in three guiding-manipulators completely controlled as a slave robot by a surgeon in a remote place. To use this system most efficiently, we investigated the suitable distance between an object lens of the endoscope and a target. Actual working territory (AWT) and actual working angle (AWA) of the forceps in the endoscopical operative field (EOF) were measured by changing the distance between the lens and the target. AWT ratio (AWT/EOF) and AWA ratio (AWA/360) decreased from 58% to 12% and increased from 39% to 85% respectively as the distance became longer. When the distance exceeds 13 mm, AWA did not increase more than 85%, and AWT kept decreasing. For the effective use of the system, the optimal distance between the lens and the target should be within 13 mm, and the system will demonstrate its ability to the maximum at the distance of 8mm.

Endoscopes↗

PubMed2002

Compartments in arteriovenous malformation nidi demonstrated with rotational three-dimensional digital subtraction angiography by using selective microcatheterization. Report of three cases.

Although in several histological studies of arteriovenous malformation (AVM) nidi the presence of compartments has been documented, no clinical study has been published. The present study was conducted to determine the presence of nidus compartments in clinical cases by using a new radiographic method. Two patients with unruptured and one with a ruptured AVM (all Spetzler-Martin Grade III) were studied. A microcatheter was superselectively introduced into each of two or three feeding arteries of the AVMs under three-dimensional (3D) angiographic guidance to obtain 3D images of the nidus by using rotational digital subtraction angiography. On 3D images the different feeding arteries were found to be independent from one another, which allowed the authors to confirm the presence of compartments. On the other hand, separate feeding arteries often had a common draining vessel. Compartments in AVM nidi were demonstrated by a novel rotational 3D angiographic procedure by using superselective microcatheterization, which should be useful for designing treatment strategies for large and complex AVMs.

Angiography, Digital Subtraction↗