Takeki Ogawa

Age-Associated Increases in Poor Outcomes after Traumatic Brain Injury: A Report from the Japan Neurotrauma Data Bank

Age is an important factor influencing outcome after severe traumatic brain injury (TBI). In general, the older the victim, the higher the probability of a poor outcome. To investigate the mechanism underlying the link between age and outcome, the data for 797 patients enrolled in the Japan Neurotrauma Data Bank (JNTDB), aged 6 years or older, with Glasgow Coma Scale (GCS) scores of 8 or less on admission or deterioration to that level within 48 h of impact were analyzed. Thirty-eight percent of the patients were between the ages of 40 and 69 years, and 24% of the patients were older than 69 years. Older patients had higher rates of mortality and lower rates of favorable outcome. The frequency of mass lesions which were associated with poorer outcomes significantly increased with age, but regardless of the intracranial lesion type, older patients had poorer outcomes. The GCS score and the occurrence of systemic complications did not differ significantly according to age. Multiple systemic injury was less frequent in older patients. The varied occurrence of intracranial lesion types according to age is likely caused by the disparity between the young and aged brain in the progression of secondary brain injury. Alteration in the pathophysiological response, which is related to the development of secondary brain injury in the aging brain, probably contributes to more severe and irreversible brain damage in older patients, and is thus associated with poor outcomes.

Protective effect of mild hypothermia on symptomatic vasospasm: a preliminary report.

Mild hypothermia (32-34 degrees C of brain temperature) was used for brain protection in patients with progressive ischemic neurological deficits associated with severe cerebral vasospasm and who did not respond to medical treatment or intravascular angioplasty. Results showed that 2 of 3 patients in Hunt & Kosnik grade I to III and 2 patients who underwent delayed operation on day 5 and 9 each and had ischemic neurological deficits made good recovery with this treatment. Favourable outcome was obtained in 4 of 9 patients in grade IV and V. Mild hypothermia is thought to provide brain protection in critical ischemia due to severe cerebral vasospasm and can lengthen therapeutic time to employ angioplasty and intraarterial Papaverin infusion.

Combined surgical and endovascular treatment of complex cerebrovascular diseases in the hybrid operating room

Background Although most neurovascular diseases can be treated either by microsurgical or endovascular means, a subset of patients may require a combined approach. Patient transfer from the operating room (OR) to the angiosuite has been a fundamental drawback of this type of approach. Objective The purpose of this study is to report our clinical experience performing combined surgical and endovascular procedures for neurovascular diseases in the hybrid OR. Methods 29 patients with neurovascular diseases underwent combined endovascular and surgical procedures in a single session: 16 were scheduled combined treatment and 13 were emergency combined procedures. Of the emergency cases, three were rescue surgeries after endovascular complications. Three patients had ruptured intracranial aneurysms, eight had unruptured intracranial aneurysms, eight had arteriovenous malformations and eight had arteriovenous fistulae; two patients had either a spinal tumor or dural arteriovenous fistulae. Results All combined procedures were performed in a single session without changing the patients surgical position. In cases of ruptured arteriovenous malformations or aneurysms with hematoma, an emergency embolization was performed to assist the surgical procedure. Combined superficial temporal artery–middle cerebral artery (STA–MCA) bypass followed by endovascular parent artery trapping were successfully performed for complex large or giant aneurysms. There were two periprocedural ischemic complications. Of the three patients who underwent surgical rescue after endovascular complications, two remained intact and one died despite immediate surgical procedures. Conclusion A combined endovascular and surgical approach conducted in a hybrid OR provides a new strategy for the treatment of complex neurovascular diseases.

Infected subdural hematoma

A case is presented in which Escherichia coli seeded a pre-existing chronic subdural hematoma. A 77-year-old woman was admitted to our hospital because of lethargy, left hemiparesis and fever. Drainage through a burr hole was performed with the diagnosis of bilateral chronic subdural hematoma. Operative findings revealed the infected subdural hematoma on the right side and non-infected subdural hematoma on the left side. Cultures of the subdural hematoma grew Escherichia coli. In view of the pyuria, the etiology of the infected subdural hematoma was postulated to be a urinary tract infection. In the majority of 14 reported cases, the causative organisms were Escherichia coli, Salmonella, and the systemic sources of infection included the urinary tract, gastrointestinal disease, or were unknown. The possibility of infected subdural hematoma should be considered when computed tomography findings suggestive of chronic subdural hematoma exist in a patient with signs of infection.

Treatment of vasogenic brain edema with arginine vasopressin receptor antagonist--an experimental study.

We determined the effect of a centrally administered V1 receptor antagonist of arginine vasopressin on the brain water content in an animal model of vasogenic brain edema. Using adult rats, a cold injury was induced in the left hemisphere of the brain by applying a frozen copper rod. 50 ng of V1 receptor antagonist was administered into the left lateral ventricle 10 minutes prior to and/or 1 hour after injury. Twenty four hours after the cold injury, the brain water and sodium contents and plasma osmolality were measured. The V1 receptor antagonist significantly suppressed the increase of the brain water and sodium contents in the cortical structure adjacent to the lesion without any changes in plasma osmolality. Our results demonstrate the effectiveness of a V1 receptor antagonist of vasopressin on vasogenic brain edema.

Treatment of arteriovenous malformation of the brain--preliminary experience.

With the availability of new techniques, such as intravascular embolisation and radiosurgery, the therapeutic approach to arteriovenous malformations (AVMs) of the brain has recently been modified. The present study reports the authors, experiences in treating AVMs over the past 13 years. Spetzler-Martin grading of AVMs was I and II in 19 cases, III in 12, IV in 5 and V in 1 case. Four therapeutic regimens were utilised: surgical resection alone, embolisation and resection, and radiosurgery alone or after surgical resection. Generally, for low-grade AVMs (Spetzler-Martin grades I, II and III), the therapeutic choice was surgical resection in 27 cases, in combination with pre-operative embolisation in two of these patients. Two cases received radiotherapy only and one case received radiosurgery after embolisation, while one case was treated conservatively. Of the five cases of grade IV, four required surgical treatment, whereas the fifth case was treated conservatively. Favourable results (good recovery and moderate disability) were obtained in 96% of the low-grade AVMs as compared with the high-grade AVMs (66%) that had a poor outcome (due to primary brain damage resulting from haemorrhage at the onset in three cases and due to postoperative re-bleeding in one case). This report summarises preliminary experience in treating intracranial AVMs by surgical resection, intravascular embolisation and radiotherapy. Good therapeutic results can be expected by combining these therapeutic modalities.

Substantial fluctuation of acoustic intensity transmittance through a bone-phantom plate and its equalization by modulation of ultrasound frequency.

For safe and efficient sonothrombolysis therapies, accurate estimation of ultrasound transmittance through the human skull is essential. The present study clarifies uncertainty surrounding this transmittance and experimentally verifies the equalization of transmittance through the modulation of ultrasound frequency. By changing three factors (ultrasound frequency, the thickness of a bone-phantom plate, and the distance between a transducer and a bone-phantom plate), we measured the intensity of ultrasound passing through the plate. Two activating methods, sinusoidal waves at 500 kHz and modulated waves, were compared. When we changed (1) the distance between a transducer and a bone-phantom plate and (2) the thickness of the bone-phantom plate, ultrasound transmittance through the plates substantially fluctuated. The substantial fluctuation in transmittance was observed also for a cut piece of human temporal skull bone. This fluctuation significantly declined for the modulated wave. In conclusion, modulation of ultrasound frequency can equalize the transmittance with an approximately 30-65% fluctuation drop and an approximately 40% fluctuation drop for a bone-phantom plate and for a cut piece of skull bone, respectively. By using modulated waves, we can develop safer and more effective sonothrombolysis therapies.

An uncovered risk factor of sonothrombolysis: Substantial fluctuation of ultrasound transmittance through the human skull

&NA; Sonothrombolysis is one of the most feasible methods for enhancing clot lysis with a recombinant tissue plasminogen activator (rt‐PA) in cases of acute ischemic strokes. For safe and efficient clinical practices of sonothrombolysis, accurate estimation of ultrasound transmittance through the human skull is critical. Previously, we reported substantial and periodic fluctuation of ultrasound transmittance through a bone‐phantom plate following changes to ultrasound frequency, the thickness of the bone‐phantom plate, and the distance between a transducer and the bone‐phantom plate. In the present study, we clarify the transmittance behavior of medium‐frequency ultrasound (from 400 kHz to 600 kHz) through the human skull, and examine reduction of the transmittance fluctuation. For the study, we measured transmittance of sinusoidal ultrasound waves at 400 kHz, 500 kHz, and 600 kHz at 13 temple spots on 3 human skulls by changing the distance between a transducer and the skull bone, and found substantial and periodic fluctuation in the transmittance behaviors for these sinusoidal voltage excitations. Degrees of the fluctuation varied depending on the measurement spots. A fluctuation ratio between the maximum transmittance and the minimum transmittance reached 3 in some spots. This large transmittance fluctuation is considered to be a risk factor for sonothrombolysis therapies. We examined a modulated ultrasound wave to reduce the fluctuation, and succeeded in obtaining considerable reduction. The average fluctuation ratios for 400‐kHz, 500‐kHz, and 600‐kHz waves were 2.38, 2.38, and 2.07, respectively. We successfully reduced the ratio to 1.72 by using a periodic selection of random frequency (PSRF)‐type of modulation wave. The thus obtained results indicate that attention to the fluctuation in ultrasound transmittance through the skull is necessary for safe and effective sonothrombolysis therapies, and that modulated ultrasound waves constitute a powerful method for reducing the risk of fluctuation. HighlightsWe measured ultrasound transmittance through the human skull for several frequencies around 500 kHz.We found substantial and periodic fluctuation in the ultrasound transmittance.This fluctuation significantly declined with the use of modulated ultrasound.

An In Vitro Assay for Sonothrombolysis Based on the Spectrophotometric Measurement of Clot Thickness: A New In Vitro Thrombolysis Assay Method

For improved thrombolysis therapy based on ultrasound irradiation, researchers and practitioners would strongly benefit from an easy and efficient in vitro assay system of thrombolysis activity involving irradiated ultrasound. For the present study, we designed a new in vitro sonothrombolysis assay system using a sheet‐type clot.

Early initiation of steroid pulse therapy for neuromyelitis optica in an emergency room setting

A 40‐year‐old man presented to the emergency room with visual impairment, dysesthesia of lower legs, and urinary retention. Two days before admission, he was consulted to the neurology department due to bilateral optic neuritis and scheduled the magnetic resonance imaging of spine. However, the urinary retention deteriorated acutely and he came to the emergency room. On arrival, the plain magnetic resonance image of his spine showed diffuse hyperintensity signals of the spinal cord in T2‐weighted images. He was diagnosed with neuromyelitis optica and steroid pulse therapy was initiated.