From its beginning almost 50 years ago, modern Japanese neurological surgery has made great advances. In the past 25 years this has taken place at ever increasing speed. Since I first visited Japan 23 years ago I have seen many changes, not only in neurosurgery but in many other ways. Initially Araki, Tanaka and Shimizu were the leaders. They have now been replaced by their students—Sano, Hajime Handa, and Ishii. The contributions of Japanese neurosurgery to knowledge have been numerous. These have been particularly striking in cerebral vascular diseases. Japan has achieved this success because it has taken advantage of the knowledge developed in other countries. Other changes have occurred. Among these are the remarkable mastery of the English language which has taken place in Japan. Another is the change from authoritarianism in Japan to an attitude of free discussion and exchange of ideas. Japan still has more to contribute. It must open its clinics to young neurosurgeons from the rest of the world. It must develop research designed to solve the problems of cerebral gliomas, cerebral vasospasm, traumatic injury to the brain and spinal cord, and the etiology and prevention of congenital defects of the central nervous system.
The authors obtained the following results in this experiment in which monkeys were subjected to frontal and occipital blows with their heads in an unrestrained condition. 1) With respect to the impact to the head and the occurrence of concussion, translational acceleration is more important than rotational acceleration. 2) The concussion threshold of monkeys was an equal speed curve of 16 m/s for occipital blows, while in the case of frontal blows, a hyperbolic curve which is somewhat higher than that for occipital blows was obtained. This concussion tolerance curve was converted into the concussion tolerance curve for humans by means of dimensional analysis. 3) A close correlation was suggested between changes in the EEG amplitude and the severity of the concussion. The more severe the concussion, the greater the decrease in the EEG amplitude. 4) The concussions could be classified into three types pathologically. The first type showed capillary dilatation and vascular permeability. The second type showed hemorrhages at sites far from the cerebral cortex and the third type showed hemorrhages in the cerebral cortex. The second and third types were in parallel with the severity of the concussion.
The pathophysiological response and morphological damage from concussion caused by rotational angular acceleration impact were studied. In all monkeys tested, concussion syndromes were induced by impact in the range of 26.5 ?? 136.4×103 rad/sec2 with a duration of 1.03 ?? 9.09 msec. The morphological findings revealed two types of brain damage. One was a sharply demarcated vital dye-stained lesion which represented an ischemic lesion with occlusion of small vessels at the base of the lesion in the frontal lobe on the side opposite the impact site. The other consisted of scattered cellular damage in the lower medulla and medullospinal junction without staining by vital dye, which was observed on the monkey suffered from concussion by linear acceleration impact.20) In the vital dye-stained lesions, the local cerebral blood flow was reduced and the partial oxygen pressure decreased until 2 hours after impact. Lactic acid increased, ATP content decreased and there was no increase in free radicals. In the border zone of the lesions, local cerebral blood flow decreased in the first 1 hour, but increased 1.5 hrs after impact. Also, free radicals increased in the border zone despite the lack of change in lactic acid and ATP contents compared with the vital dye-stained lesions themselves. There was no variation in amplitude or latency of the brain stem response to auditory stimulation, but the somatosensory response at the sensory cortex changed to a low amplitude of elongation of the latency in the concussion caused by the rotational acceleration impact. These findings clearly suggest that there are two types of brain damage in concussions caused by rotational acceleration impact.
The findings of repeated CT scans, clinical courses and pathological studies in 28 cases of delayed post-traumatic intracerebral hematoma were studied retrospectively to elucidate the mechanism of bleeding and to establish adequate treatment. Based on the results obtained, it became clear that there are two types of delayed hematoma. In 10 of the 28 cases, initial CT findings within 6 hours after head injury revealed cerebral contusion or hemorrhagic contusion, and spots of high density scattered in the low density zone gradually became confluent to form an irregularly shaped hematoma according to follow-up CT findings. This was termed “hematoma within a contusional area.” In 15 of the 28 cases, initial CT findings within 6 hours after head injury revealed no abnormal density within the brain and the hematoma appeared suddenly 3 ?? 6 days after the injury. In eight of the 15 cases, emergency surgery was performed for the removal of epidural or subdural hematoma. This type of hematoma is termed “contusional hematoma” and constitutes the second group. In three of the 28 cases, both types of hematoma were observed. Based on histological findings for the two types of delayed hematoma. The first group may be induced by an anoxic vasodilation mechanism (Evans et al.9)), while the second group may be derived from a different mechanism related to ishemic changes and the free radical reaction caused by the reflow phenomenon (Tsubokawa et al.14-16)) It is important to establish correct diagnoses 1 for delayed hematomas based on differences between follow-up findings of repeated CT and an initial CT performed within 6 hours after head injury since the operative indications and operative results for the two groups are different as indicated by our 28 cases.
Since CT scans make it possible to demonstrate precise morphological and anatomicopathological findings, small brain lesions are frequently found on CT scans, in spite of the short duration of unconsciousness after head trauma. Thirty six out of approximately 500 cases which received CT examinations within two weeks after head injury were selected and analyzed. In these cases, almost all high or low density lesions were detected in the tip and/or base of the frontal and/or temporal lobes adjacent to the skull. Causes of the injury were traffic accidents (33.3%), falls on the floor or road (33.3%), and falls down stairs, out of beds, etc. (25.5%). Clinical manifestations before CT examinations were heaviness in the head or headache (36.0%), and nausea and vomiting (33.3%), but thirteen out of 36 patients had no symptoms or complaints. None of the 36 patients showed any neurological dysfunctions suggesting focal damages. Fourteen of the above-mentioned 36 patients (38.9%) had skull fractures and the remaining 22 (61.1%) did not, and there was no significant difference between the two. On the contrary, the incidence of skull fractures in cases in which CT scans were normal was 12.4% which was significantly different from the figure of 38.9% in patients with fractures and CT abnormalities. It is inferred that the deformation of the skull at the time of impact is one of the important factors in the development of brain contusions. To clarify the correlation between the duration of the initial unconsciousness and abnormal CT findings, 219 consecutive cases of head injuries underwent CT scans without considering their severity. Out of 171 patients who were conscious or lost consciousness in less than 10 minutes, 13 (7.6%) had small lesions in CT scans. Of 12 cases with a state of unconsciousness from 10 to 60 minutes in duration, three (25.0%) had abnormal CT findings. In all cases which were unconscious for more than 6 hours, brain lesions were detected by CT scans.
Five hundred cases of acute head injury were analyzed on the basis of clinical severity, CT findings and outcome. Parenchymal lesions, which were the most important information in predicting the outcome, were classified into six categories: Isodensity WITHOUT Mass Effect, Isodensity WITH Mass Effect, High Density, High and Low Density Complex, Low Density, and Acute Diffuse Cerebral Swelling. Isodensity WITH Mass Effect was related to the worst outcome (59% mortality and 24% functional recovery). This finding was obtained 2 and a half hours following trauma and High and Low Density Complex eventually appeared in repeated CT. Epidural hematoma was associated with parenchymal lesions in only six (40%) out of 15 cases and acute subdural hematoma was accompanied by parenchymal lesions in 21 (84%) out of 25 cases. The remarkable differences in the outcome of those two extracerebral hematomas were entirely dependent on the associated parenchymal lesions. In the minor head injury group, parenchymal lesions were not rare (8.5%) in patients with a loss of consciousness even for a brief period. To follow the rapid dynamic changes in parenchymal lesions, the importance of repeated CT was emphasized.
A case of massive traumatic hematoma of the basal ganglia which simulated a spontaneous intracerebral hematoma and was successfully treated is reported. The possible mechanism of production of these lesions following head injury is also discussed.
A fast, easy anastomotic technique with a high patency rate would facilitate the development of microvascular surgery. This article describes a new nonsuture method of end-to-side microvascular anastomosis using a soluble polyvinyl alcohol (PVA) T—shaped tube as an internal stent and plastic adhesive. Two kinds of T—shaped tubes were used: Type I tube had a short straight tube connected to a long straight tube at the midpoint and the Type II tube was a long bent tube with a short straight tube connected to it. The walls of each tube consisted of three concentric layers made of two PVA's with different solubilities. Seventy end-to-side anastomoses were performed using both common carotid arteries of rats. These consisted of three groups, I, IIA, and IIB. I and II were the types of T-tubes employed, and A had less plastic adhesive than B. Evaluations were performed 2 weeks and 3 months after surgery. The anastomotic technique was easily accomplished, taking approximately 8 minutes to complete. On the first evaluation the patency rates were more than 90% in all groups, but anastomotic aneurysms developed in I(17%) and IIA (19%). No aneurysms were observed in IIB where the anastomotic sites were reinforced by adding plastic adhesive after the blood flow was reestablished. Moreover, a high patency rate (95%) was maintained even at the second evaluation in IIB.
To develop a new balloon catheter technique, three types of detachable balloon catheters, a catheter delivery system and a radiopaque solidifying liquid were prepared. In the first type of detachable balloon catheter, the balloon was detached from the catheter by rotation at the specially designed joint connecting the balloon and catheter. The joint was made of ethylene-vinylalcohol copolymer. In the second type of detachable balloon catheter, the balloon was detached from the catheter by dissolution of a specially designed joint. The joint was made from a polyvinylalcohol tube and had two electrodes. When high frequency electrical current was applied, the resulting heat dissolved the joint within one second. The third detachable balloon catheter was a modification of the second type of catheter. A pinhole was made at the tip of the balloon. Through this pinhole, solidifying liquid such as isobutyl 2-cyanoacrylate can be introduced into the artery. At present, twenty-three superselective catheterizations including nine embolizations have been performed. Eight embolizations were performed in patients with intradural cerebral aneurysms and arteriovenous malformations. Two complications occurred. In arteriovenous malformations, embolization using a detachable balloon catheter seemed to be an effective adjunctive treatment prior to operative removal. In aneurysms, permanent embolization of the neck of the aneurysm appeared to be most important. Posttraumatic carotidcavernous sinus fistulas and some spontaneous carotid-cavernous sinus fistulas could be completely embolized using a detachable balloon catheter while preserving the carotid blood flow.
Radiometric studies were conducted in 21 cases of posterior inferior cerebellar aneurysms and 52 normal subjects to determine the variability of location of the vertebral-posterior inferior cerebellar artery complex in the posterior fossa. Accessibility using a lateral suboccipital approach was evaluated in relation to the radiometric data. Lateral suboccipital openings offered a sufficient surgical field in all cases under minimal retraction of the cerebellum and the results were satisfactory. The range of accessibility of this lateral approach was between 0 to 17 mm from the midline, 1 to 23 mm from the foramen magnum, 6 to 16 mm from the clivus and 35 to 61 mm from the posterior clinoid process. Postoperative neurological deficits were seen in patients with an aneurysm within 10 mm of the midline and at more than 13 mm from the clivus. Advantages of the lateral suboccipital approach are discussed.
A series of 44 patients with hypertensive cerebellar hemorrhage and nine patients with cerebellar hemorrhage caused by small angiomas is described. Hypertensive hemorrhage occurred most frequently in the patients in their seventies, whereas the onset of angiomacaused hemorrhage was often seen below the age of 40. Clinical syndromes of cerebellar hemorrhages can be categorized into three basic types: the vertigo syndrome, cerebellar dysfunction syndrome and brain stem compression syndrome. Patients with small ( ≥2 cm in diameter in CT scans) and medium-sized (2 cm <3 cm in diameter) hematomas usually presented one of the former two syndromes with no or only mild impairment of consciousness. However, unless prompt surgical decompression was carried out, most patients with large ( ≥3 cm) hematomas deteriorated into unresponsive conditions and developed signs of brain stem compression. Surgical mortality was 32% in the hypertensive group, while it was 0% in the angioma group. Mortality as well as morbidity in both groups was strongly influenced by the preoperative status of consciousness. Our results suggest that substantial improvement could be obtained in the overall outcome of this disease by emergency craniectomy and removal of hematomas in all patients with large hematomas regardless of the levels of consciousness and regardless of the causes of bleeding. Furthermore, when clinical information and CT findings are suggestive of a “cryptic” angioma as the causative lesion, posterior fossa surgery may be indicated to extirpate the lesion, even if the hematoma is small.
A series of 18 patients with hypertensive cerebellar hemorrhages diagnosed with computed tomography (CT) is described. The clinical course appeared to fall into three groups. Group I (56%) did not exhibit consciousness disturbances and improved spontaneously. Group II (22%) developed gradual deterioration of consciousness. Group III (22%) became comatose within 12 hours and developed signs of brain stem dysfunction. The CT findings reflected the three clinical groups. The CT of Group I revealed a small hematoma ( ≥24 mm) with or without ventricular hemorrhage. The scans of Group II demonstrated hematomas of moderate volume (34 ?? 52 mm) with a partial defect of the perimesencephalic cisterns. The CT of Group III showed a large hematoma ( ≥43 mm) with massive ventricular hemorrhaging and obstructive hydrocephalus. Severe mass effects on the brain stem were also seen. The patients of Group I should be treated by conservative therapy and Group II by emergent suboccipital craniectomy and evacuation of the hematoma. Surgical indication for the patients in Group III could not be determined.
Seven patients with spontaneous carotid-cavernous fistulas are reported. Angiography showed a direct shunt between the internal carotid artery and the cavernous sinus in twc patients (Cases 2 and 6) and dural arteriovenous shunts in the cavernous sinus region in five patients (Cases 1, 3, 4, 5 and 7). They were treated by ligation of the external carotid artery (Cases 1 and 3), occlusion of the common carotid artery (Case 6), embolization of the fistula (Case 2), embolization and ligation of the external carotid artery and excision of the dural lesion (Case 5), embolization and ligation of the external carotid artery (Case 7), or irradiation (Case 4). Post-treatment angiography showed complete closure of the fistulas in four patients (Cases 1, 2, 4 and 7). In two patients (Cases 3 and 5), small angiomatous lesions were noted, one which regressed spontaneously one year postoperatively and one which improved clinically. We suggest that in surgically inaccessible shunts, irradiation may be a viable alternative treatment.
The angiogenic activity in the supernatants of cultured cells derived from human CNS tumors was examined by a bioassay method using chick chorioallantoic membrane (CAM). A quantitative assessment was designed to obtain a more accurate evaluation of angiogenesis on CAM. Three out of five glioma cell lines, three out of four primary cultures of meningiomas and one metastatic tumor cell line showed angiogenic activity in the culture supernatants. The angiogenic activity was destroyed by ribonuclease or heating at 80°C for 30 minutes but remained intact with exposure to trypsin, deoxyribonuclease or heating at 56°C for 30 minutes. TAF samples obtained from glioma cells which had been irradiated (2, 500 R) before TAF extraction, also showed angiogenic activity. TAF was present in the supernatants of long-term cultured human CNS tumor cell lines and primary cultures of meningiomas. Thus, the nature of TAF may related to RNA of the tumor cells and the TAF producing ability of these cells is apparently not inhibited by irradiation.
Chondromas rarely develop in the cranial fossa. Among 150 cases of intracranial chondromas reported, only ten arose within the sella turcica. A case of a 50-year-old man with intrasellar chondroma is presented. He had a chiasmal syndrome which lead us to the preoperative diagnosis of pituitary adenoma. It is very hard to differentiate an intrasellar chondroma from a pituitary adenoma or craniopharyngioma before histological examination. Computed tomography scan showed that the density of intrasellar chondroma is slightly lower than that of pituitary adenoma.
A case of an intradiploic leptomeningeal cyst of the posterior fossa in a 7-year-old boy is reported. Plain skull films demonstrated characteristic findings. The cause of the lesion was attributed to a head injury at 2 years of age. The pathogenesis and pathomechanism are discussed in contrast with supratentorial leptomeningeal cysts.