Cochlear nerve injuries caused by surgical manipulation in the cerebellopontine (CP) angle were electrophysiologically and morphologically investigated in dogs. Operative procedures similar to those performed in the CP angle in humans were performed. Lateral-to-medial retraction of the cerebellar hemispheres applied traction force to the cochlear nerve. Brainstem auditory evoked potentials and compound action potentials from the intracranial portions of the cochlear nerves were recorded during the procedures. As a result of the traction force produced by manipulations in the CP angle, the Schwann-glial junctions of the cochlear nerve were separated in some dogs. The exit portions of the cochlear nerve fibers and the branches of the internal auditory artery from the osseous spinal lamina were most vulnerable to the traction force derived from such manipulations. The cochlear nerve fibers from the basal turn of the cochlea tended to be easily removed from the tractus spiralis foraminosus at the fundus of the internal auditory canal. This finding may explain occasional occurrence of postoperative high frequency hearing loss among patients who undergo surgical manipulation in the CP angle. In some cases, massive hemorrhage and exudation of plasma were observed in the deep portion of the modiolus, where they compressed the cochlear nerve trunk. This is apparently one of the causes of intraoperative failure of cochlear function. In this study, no correlations between electrophysiological and morphological findings were established.
It has been demonstrated that neoplastic cell surface constituents affect interactions between tumor cells and their host environments during metastasis. A recently discovered glycoprotein adhesive factor (AF) on the surfaces of brain tumor cells is apparently active in multicellular spheroid formation and is assumed to be involved in the adhesion of brain tumor cells. In addition, it has been documented that the peanut agglutinin (PNA) receptor is a factor in the metastatic potential of cancer cells and that fibronectin (FN) plays a role in the attachment of cancer cells to the basal lamina. The authors measured AF and PNA receptor on the surfaces of human brain tumor cells and FN in the stroma of the brain tumor tissue and found a significant relationship between the frequency of subarachnoid dissemination and the presence of these substances. Their results suggest that AF may be very important in the process of exfoliation or dissociation of brain tumor cells from the original tumor into the cerebrospinal fluid cavity and that stromal FN participates in the attachment of migrating tumor cells to new sites. PNA receptor did not appear to be involved in tumor cell dissemination into the cerebrospinal fluid cavity.
Pituitary cysts are fairly often found incidentally in anatomical studies, but symptomatic cysts are relatively uncommon. In this study, the histological characteristics of 42 asymptomatic and three symptomatic Rathke's cleft cysts were examined and compared. The 42 cysts found incidentally at autopsy were classified as small (less than 1 mm in diameter), medium (1 to 5 mm), or large (over 5 mm). There were 23 small (55%), 13 medium (31%), and six large (14%) cysts. The mean ages of the three patient groups were 66, 60, and 53 years, respectively. Flattened epithelial cells were the most common cells in small cysts, while cuboidal to columnar epithelial cells were more prevalent in medium and large cysts. The larger cysts tended to contain cilia. The three symptomatic cysts were histologically confirmed to be Rathke's cleft cysts by their characteristic ciliated columnar epithelial lining. No essential histological differences were observed between asymptomatic and symptomatic cysts, and the mechanism of change from asymptomatic to symptomatic Rathke's cleft cyst was not clarified. Small nests of epithelium at the junction of the pars tuberalis and pituitary stalk are considered to be remnants of Rathke's pouch and are thought to give rise to craniopharyngioma. In their most typical forms, Rathke's cleft cysts and craniopharyngiomas are histologically distinguishable, craniopharyngiomas being composed of stratified squamous epithelium and simple Rathke's cleft cysts of a layer of cuboidal or columnar epithelium on a basement membrane. It is believed that the most important difference is that Rathke's cleft cyst is a simple cystic enlargement and does not undergo the type of neoplastic transformation that occurs in craniopharyngioma. However, in the clinical situation these histological distinctions are not always clear; a mixed form may exist. Therefore, it is recommended that symptomatic intra or suprasellar cystic lesions be surgically explored, to ensure correct diagnosis and appropriate treatment.
Although it is well known that bromocriptine (BC) is effective in the treatment of functioning pituitary adenoma, this agent sometimes causes severe gastrointestinal side effects. In this study, dihydroergotoxine mesylate (EX), which is composed of ergot alkaloids and is similar to BC, was administered to 11 patients with functioning pituitary adenomas who could not tolerate the adverse effects of BC. Three patients (27%) showed clinical improvement with EX treatment alone (1 to 6 mg/day). In another patient, computed tomography demonstrated tumor shrinkage. The remaining seven patients became able to take BC with no adverse effects, after 2 to 16 weeks starting EX therapy. No patients experienced adverse effects while taking EX. These results indicate that EX is a useful alternative to BC in the treatment of functioning pituitary adenoma, particularly in patients who cannot tolerate the side effects of BC. Moreover, pretreatment with EX appears to reduce the incidence of side effects of BC.
Magnetic resonance images (MRI) of diseased cervical and lumbar intervertebral discs involving both intrinsic and extrinsic cord lesions were examined using either a 0.15 T resistive or a 0.5 T superconductive magnetic imaging system. High resolution images were obtained by means of a surface coil in most cases. The vertebrae, intervertebral discs, and spinal cord were delineated in greatest detail on spin-echo (SE) images with a long repetition time (TR) and a short echo time (proton density-weighted image), on which the spinal cord was appreciated without overshadowing by the cerebrospinal fluid-filled subarachnoid space. Protrusion of degenerated intervertebral discs into the spinal canal was clearly demonstrated not only on sagittal but also on parasagittal and transverse views. The location of protruded discs and compression of the spinal cord, caudal sac, and nerve roots were well visualized three-dimensionally. Pathological features of intervertebral discs were better appreciated on T2-weighted images with long TR and SE pulse sequences. Degeneration of intervertebral discs resulted in decreased signal intensity in cases involving lumbar disc lesions but not those involving cervical disc lesions. In a case of suspected myelomalacia, the in trinsic cord lesion resulting from traumatic disc protrusion appeared as focal low signal intensity on T1-weighted images and as somewhat high intensity on T2-weighted images. The inversion recovery sequence with median inversion time displayed an inferior image of low contrast and was judged uninformative in comparison to SE images. The authors' observations demonstrate that MRI is an essential diagnostic technique for spinal cord disorders. It very clearly delineates the anatomical structures of the spine and the features of disc degeneration. Both extrinsic and intrinsic cord abnormalities can be identified with MRI. However, it is very important to choose the proper pulse sequence so that the object of interest is plainly differentiated.
The hemodynamics of the anterior cerebral arteries (ACAs) were studied in 28 children with moyamoya disease. In 39% of 56 cerebral hemispheres, antegrade filling of the ACAs was not verified by preoperative angiography. On the other hand, adequate collateral pathways to the ACA territory were generally not achieved by encephalomyosynangiosis (EMS) or superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis. The authors have devised new surgical methods for the revascularization of the ACA territory, which they term “encephaloarteriosynangiosis” (EAS) and “encephalogaleosynangiosis” (EGS). In these procedures, one or several burr holes are made in the frontal skull, the dura mater is incised, and either the frontal branch of the STA or the pedicled galea aponeurotica stump is placed on the surface of the frontal cortex. In addition to EMS or STA-MCA anastomosis, these methods were applied to 23 cerebral hemispheres in 14 pediatric patients. In 14 cerebral hemispheres (61%) of 10 patients, postoperative external carotid angiograms showed some cortical branches in the ACA territory, and clinical improvement was achieved in patients with transient ischemic attacks affecting the lower extremities. The results of this study demonstrate that EAS and EGS are simple and useful techniques for revascularization of the ACA territory. In addition, EGS can be applied to the territory of the posterior cerebral artery.
The pathogenesis of chronic subdural hematoma is not fully understood. It is thought that fibrinolytic hyperactivity within the hematoma capsule plays an important role. However, since this hyperactivity has not been found in the systemic blood, accelerated fibrinolysis is thought to occur only locally. To evaluate coagulant and fibrinolytic activities in the peripheral blood, the authors measured fibrinopeptide A (FPA) and fibrinopeptide Bβ15-42 (FPBβ), which are relatively sensitive hematologic factors, in 14 patients with chronic subdural hematoma. Peripheral venous blood was collected within 24 hours before surgery and FPA and FPBβ levels were determined. In the eight cases followed for more than 1 month after surgery, pre and postoperative FPA and FPBβ values were compared. The possible relationship between preoperative FPBO and hematoma density as well as elevated intracranial pressure (judged by preoperative computed tomography) was also examined. The following results were obtained: 1) Preoperative FPA and FPBβ values were both statistically significantly elevated suggesting systemic acceleration of coagulant and fibrinolytic activities. FPBf levels exceeded those of FPA in almost all cases, indicating that fibrinolysis was more dramatically enhanced. 2) Many patients with high FPBβ values had high-density areas on computed tomography scans. 3) Patients with choked disc had high FPBP values, suggesting a correlation between chronic intracranial hypertension and FPBβ. 4) Postoperatively, there was a marked decrease in FPA values, whereas FPBβ values remained above normal, which may reflect persistence of ccelerated systemic fibrinolytic activity in patients with chronic subdural hematoma.
The surgical treatment of chronic subdural hematoma has evolved from membranectomy through craniotomy to burr hole irrigation. The latter approach is based on utilization of the natural absorptive process that is thought to be part of the life cycle of the hematoma. To test this theory, the authors treated fifty-nine patients with chronic subdural hematoma according to the following protocol. Local anesthesia was induced with a modified neuroleptanalgesic procedure. A single burr hole was drilled, usually in the posterior frontal region, and irrigation was carried out until the washing was clear. Subdural drainage was not employed. Patients were permitted to walk about on the following day. The outcome was better than that achieved with conventional treatment. Such complications as tension pneumocephalus and intracranial hematoma were not observed, and only one patient (1.7%) had a recurrence. The results of this study indicate that single burr hole irrigation without drainage is a very simple and effective treatment for chronic subdural hematoma. The absence of subdural drainage may be an important feature, since drainage may contribute to the development of certain postoperative complications. Also, the simplified procedure allows patients early mobility, which may be of particular benefit to the elderly.
Eight cases of intention tremor as a late complication of head injury were investigated. The patients ranged in age from 3 to 24 years. All received severe head injuries and lapsed into coma immediately afterward (Glasgow Coma Scale scores ≤8). Six patients exhibited decerebration or decortication. Hemiparesis was present in six cases and oculomotor nerve palsy in four. In the chronic stage, all patients displayed some degree of impairment of higher cortical function and five had dysarthria and/or ataxia. Initial computed tomography (CT) scans within 3 hours after the injury were obtained in five cases, of which four showed a hemorrhagic lesion in the midbrain or its surroundings. Other CT findings were diffuse cerebral swelling (four cases), intraventricular hemorrhage (three), and multiple hemorrhagic lesions (two). In the chronic stage, generalized cortical atrophy or ventricular enlargement was noted in five cases. These clinical features and CT findings indicate diffuse brain damage as well as midbrain damage and may reflect shearing injury.
A 76-year-old female developed depression and loss of appetite. On admission, in June of 1987, she was disoriented. Computed tomography (CT) revealed enhanced masses without perifocal edema in the cerebellar vermis and left occipital lobe. The cerebellar tumor was subtotally removed through a suboccipital craniectomy. Histological examination disclosed malignant lymphoma of the diffuse, large cell type. The patient underwent postoperative irradiation, and no other tumors were detected by whole-body CT or gallium scans. Her 51-year-old son had been admitted to another hospital in April of 1987, with complaints of depression and change in mental status. Neurological examination revealed right hemiparesis, and CT demonstrated an enhanced left frontal paraventricular mass and severe perifocal edema. The histological diagnosis was malignant lymphoma, and the patient received postoperative irradiation and chemotherapy. A few cases of familial extracranial malignant lymphoma have been described. However, to the authors' knowledge, this is the first reported occurrence of familial primary intracranial malignant lymphoma.
A 58-year-old male was admitted following an episode of unconsciousness. Nine years prior to this, he had undergone surgery and radiation therapy for a nasal tumor. Subsequently, he had undergone surgical excision of recurrent nasal tumors and metastases to the cervical lymph nodes. The final pathological diagnosis was paraganglioma. On admission, he had no neurological deficit other than anosmia. Laboratory studies showed no abnormalities in urinary concentrations of vanillylmandelic acid or catecholamines. Computed tomography (CT) demonstrated a calcified, heterogeneously enhanced mass in the anterior ethmoid sinus and bilateral frontal fossa. Cerebral angiography revealed a mesh-like tumor stain. Through a bifrontal craniotomy the intracranial tumor was totally removed. It was hypervascular and clearly demarcated from the surrounding cerebral tissue. The pathological diagnosis was paraganglioma without malignant features. Radiation therapy was administrated postoperatively at a total dose of 5060 rads, and follow-up CT showed regression of the ethmoid sinus tumor. As of 2 years postoperatively, the tumor has not recurred.
The authors report a case in which an enlarging skull fracture was surgically repaired on the fourth day after the initial injury. A 5-month-old boy fell from his father's arms and was hospitalized with a large, irregular protrusion in the left parieto-occipital region and right hemiparesis. Plain skull films showed a diastatic linear fracture with a maximum width of 8 mm, which expanded to 11 mm by the fourth day. Computed tomography (CT) scans revealed a cerebral contusion just beneath the fracture as well as a left subdural effusion. At operation, the contused brain tissue was found to have herniated over the bone defect. Craniotomy revealed a large dural defect, which was repaired with lyophilized dura. The patient was discharged with no neurological deficit. On the basis of a review of 58 recently reported cases of skull fracture, the authors conclude that the following conditions warrant consideration of early surgery: 1) a diastatic skull fracture with a width of at least 4 mm; 2) CT demonstration of a cerebral contusion beneath the fracture; 3) overlying scalp swelling; and 4) a neurological abnormality contralateral to the fracture. Performing surgery before the fracture gap becomes scalloped will result in more rapid neurological recovery and reduce the likelihood of enlargement of the fracture.
A 49-year-old male was hospitalized with a 1-month history of persistent headache and vomiting. Computed tomography (CT) revealed left middle fossa arachnoid cysts and a chronic subdural hygroma. The cysts were excised after evacuation of the subdural hygroma. Postoperatively, the patient did not regain consciousness and CT showed multiple intracerebral hemorrhages in both the supra and infratentorial spaces. Three months postoperatively, he was discharged with mental deficits and right hemiparesis. A review of the literature indicates that the possible pathogenic mechanism in this case was a sudden increase in cerebral blood flow due to faulty autoregulation. This devastating complication may have been avoided by simple drainage of the subdural hygroma, perhaps with the addition of cyst-peritoneal shunting.
A 57-year-old male was hospitalized with stroke on the day of onset. An initial computed tomography revealed a hemorrhage in the left caudate nucleus. Common carotid angiography demonstrated a carotid-vertebral anastomosis. Complete selective external carotid angiography disclosed the proatlantal intersegmental and occipital arteries arising from the external carotid artery at the level of the atlas. The proatlantal intersegmental artery, which is one type of persistent primitive carotid-vertebrobasilar anastomosis, is rarely associated with hypertensive intracerebral hemorrhage, according to the literature.
Two cases of subarachnoid hemorrhage caused by rupture of a basilar bifurcation aneurysm associated with occlusion of the internal carotid artey (ICA) at the neck are presented. Case 1, a 71year-old female, was hospitalized in a coma. Angiography demonstrated occlusion of the bilateral ICA, collateral blood supply through the branches of the foramen rotundum or vidian artery from the maxillary arteries and right posterior communicating artery, and a saccular aneurysm at the basilar bifurcation. The patient died 1 month later following rerupture of the aneurysm. Case 2, a 64-year-old male, was hospitalized for drowsiness. Angiography showed occlusion of the right ICA, collateral blood supply through a tortuous artery (a vidian artery), and a large aneurysm at the basilar bifurcation. Posterior circulation supplied anteriorly through the right posterior communicating artery. The patient died 1 month later because of rerupture of the aneurysm. Laminar thrombosis of the right ICA and an anastomotic vessel, seemingly a branch of the foramen rotundum or a vidian artery, were demonstrated by autopsy. The combination of cerebral aneurysm and collateral circulation is extremely rare in cases of occlusion of the ICA. The two cases described here suggest that hemodynamic stress is an important factor in the formation of cerebral aneurysms.