Radiation-induced schwannomas.

The histopathology and clinical course of three patients with schwannomas of the brain and high cervical cord after therapeutic irradiation for intracranial malignancy and for ringworm of the scalp are described. Earlier reports in the literature indicated that radiation of the scalp may induce tumors in the head and neck. It is therefore suggested that therapeutic irradiation in these instances was a causative factor in the genesis of these tumors.

Hormone receptors in initially excised versus recurrent intracranial meningiomas.

Intracranial meningiomas from 51 surgical patients consecutively treated during an 18-month period were evaluated for the presence of receptors to progesterone and estrogen. Thirty-eight patients underwent initial resection during this time and 13 underwent reoperation for recurrent disease. With positivity defined as receptor levels greater than 10 fmol/mg of cytosol protein, 84% of all the meningiomas were positive for progesterone receptors, whereas only 33% were positive for estrogen receptors. Among the recurrent meningiomas, 92% showed evidence of progesterone receptors and 54% of estrogen receptors; these figures were not significantly different from the corresponding incidence of 82% and 26%, respectively, among the initially excised tumors. However, the mean concentration of progesterone receptors in the recurrent tumor group was significantly higher when compared to the concentration in the initially excised group (p < 0.02). Twenty meningiomas (39%) were considered to be radiation-induced, since they were removed from patients who had received scalp irradiation during childhood. The incidence and concentration of receptors in the radiation-induced tumors were generally comparable to those in the spontaneous meningiomas. This study confirms previous reports of a high incidence of hormone receptors, mainly for progesterone, in meningiomas. In addition, it shows that in recurrent meningiomas these receptors persist and even increase. The results therefore support hormone treatment for nonresectable meningiomas, especially at recurrence.

Brain edema and neurological status with rapid infusion of lactated Ringer's or 5% dextrose solution following head trauma.

Rapid infusion of 0.25 ml/g of 0.9% saline over 30 minutes has been shown to have no effect on electrolyte balance, neurological severity score (NSS), or brain edema, following closed head trauma (CHT). Rapid infusion of the same volume of 5% dextrose solution decreased blood sodium concentration, increased edema, and decreased NSS following CHT. In the present study the authors examined the effect of rapid infusion (30 minutes) of smaller volumes of 5% dextrose (0.08 ml/g and 0.16 ml/g) and of 0.25 ml/g lactated Ringer's solution on blood electrolyte concentrations, plasma osmolality, brain edema, and NSS. The purposes of this study were to determine whether rapid infusion of a large volume of lactated Ringer's solution could be given after CHT without increasing mortality or brain edema or producing electrolyte disturbances, and whether small volumes of 5% dextrose could be infused with few or none of the deleterious effects expected from large volumes of 5% dextrose. One hundred eighteen rats, which survived halothane anesthesia and CHT, were randomly assigned to one of 15 experimental groups. Fluids were administered beginning 1 hour after scalp incision or CHT. The NSS, extent of edema, blood electrolyte concentrations, and plasma osmolality in the groups treated with lactated Ringer's solution were not significantly different from those values in the nontreated groups. In addition, the mortality rate after CHT was not increased by administration of lactated Ringer's solution. The groups treated with 5% dextrose solution showed a significantly higher mortality rate, but the NSSs of the surviving rats were not different from controls. None of the groups treated with 0.16 ml/g 5% dextrose solution survived 24 hours. Although blood glucose concentration increased to 1126 +/- 102 g% (mean +/- standard deviation) and 1568 +/- 283 g% and blood sodium concentration decreased to 110.4 +/- 4.6 mEq/L and 92.0 +/- 5.2 mEq/L in the groups treated with 0.08 ml/g and 0.16 ml/g of 5% dextrose solution, respectively, plasma osmolality was normal and no significant difference could be found between the brain tissue specific gravity of animals in the nontreated and 5% dextrose treatment groups. It is concluded that in the CHT model used in this study, the large volume of lactated Ringer's solution did not affect blood electrolyte concentration, neurological outcome, or formation of brain edema, whereas smaller volumes of 5% dextrose solution increased blood glucose and decreased blood sodium concentrations, did not affect plasma osmolality, and had a deleterious effect on neurological outcome.

Effect of magnesium given 1 hour after head trauma on brain edema and neurological outcome.

Excitatory amino acids (EAA), mainly glutamate and aspartate, are released in excessive amounts from terminals of ischemic or traumatically injured neurons. These excessive levels of EAAs initiate a cascade of events believed to lead to secondary delayed damage to the surrounding brain. The N-methyl-D-aspartate receptor antagonists MK-801 and ketamine are reported to suppress excessive EAA release and to attenuate the development of focal brain edema following neuronal injury. Magnesium is also reported to work at the postsynaptic receptor to reduce the neurotoxic effect of glutamate. The present study was undertaken to examine the effect of postinjury treatment with Mg++ on brain edema and neurological outcome after traumatic brain injury. Sixty-nine rats that survived halothane anesthesia and closed head trauma (CHT) were randomly assigned to one of seven experimental groups: sham, CHT, and CHT with administration of Mg++ 1 hour postinjury. At 48 hours, brain tissue Mg++ concentration (calculated from optical density using a standard curve) was significantly increased compared to baseline levels (10.06 +/- 2.44 mg/g vs. 6.83 +/- 0.81 mg/g, p < 0.01 calculated by one-way analysis of variance). Also at 48 hours postinjury, brain tissue specific gravity in the contused hemisphere of Mg(++)-treated rats was significantly greater than that in the contused hemisphere of untreated rats, indicating attenuation of brain edema formation by Mg++. The neurological severity score (NSS) of rats treated with Mg++ improved significantly at both 18 and 48 hours, compared to baseline values obtained 1 hour after CHT but prior to administration of Mg++ (11.2 +/- 2.5 vs. 15.2 +/- 4.1, p = 0.03; and 12.3 +/- 6.1 vs. 17.3 +/- 3.6, p = 0.004, respectively). In the untreated groups, the NSS at 18 and 48 hours was not significantly different from baseline values (that is, no neurological improvement). The present study indicates that postinjury treatment with Mg++ attenuates brain edema formation and improves neurological outcome after experimental CHT.

Radiation-induced cerebral meningioma: a recognizable entity.

The authors retrospectively analyzed the clinical and histopathological findings in 201 patients with intracranial meningiomas operated on in the period 1978 to 1982. Forty-three of the patients (21.4%) had at some previous time received radiation treatment to their scalp, the majority for tinea capitis. The findings in these 43 irradiated patients were compared with those in the 158 non-irradiated patients. Several distinctive clinical and histological features were identified in the irradiated group, which suggest that radiation-induced meningiomas can be defined as a separate nosological subgroup. The use of irradiation in large numbers of children with tinea capitis in the era prior to the availability of griseofulvin may be responsible for a significantly increased incidence of intracranial meningiomas.

Early outcome and complications of the extended subcranial approach to the anterior skull base.

OBJECTIVES: To present the technique of the extended subcranial approach to the anterior skull base and to review the results in 55 patients who underwent the procedure. STUDY DESIGN: Retrospective review of the records of 55 patients who underwent the extended subcranial approach to the anterior skull base between 1994 and 1998 for the treatment of various neoplasms originating in the nasal cavity, nasopharynx, paranasal sinuses, orbit, or meninges, as well as for the repair of complex craniofacial trauma and/or cerebrospinal fluid (CSF) leak. Preoperative patient evaluation and the surgical technique are also reviewed. METHODS: Patient records were retrospectively reviewed and tabulated for age, sex, and indications for procedure, with special focus on early outcome and complications. RESULTS: Twenty-six patients underwent oncologic resections, 22 patients had reduction of complex fronto-naso-orbital and skull base fractures, and seven patients had repair of CSF leak. Significant complications in the oncologic group consisted of one hematoma requiring needle aspiration and two cases of temporary nontension pneumocephalus. In the fracture group, one patient died because of extensive intracerebral damage and multiorgan failure, and one patient had nontension pneumocephalus coupled with CSF leakage and one patient had temporary nontension pneumocephalus. The most common late complication in all three groups was anosmia. CONCLUSIONS: Based on their review, the authors conclude that the extended subcranial approach to the anterior skull base is a safe, versatile, and effective procedure for the surgical treatment of various pathological conditions involving the anterior skull base.

Infratentorial intratumoral hemorrhage.

Infratentorial intratumoral hemorrhage is infrequently reported. Owing to crowding of the vital structures in the posterior fossa, a high percentage of bleeding tumors in this region are fatal. Only six such cases of bleeding ependymomas in the posterior fossa have been documented; four of the patients died. We report a seventh case of intratumoral hemorrhage in a 4th-ventricle ependymoma. This patient survived. Reported cases of infratentorially bleeding tumors of various histologic types are reviewed. Their pathogenesis, clinical presentation, and management are discussed.

Supraorbital burr hole via a glabellar incision: a simple approach to anterior skull base.

A left subfrontopolar lesion with marked edema was totally resected utilizing a minimally invasive approach. It was possible to expose and resect the lesion, which turned out to be a tuberculoma, through a burr hole placed supraorbitally through a glabellar incision. The development and significance of minimalization techniques for surgery in the skull base region are discussed.

Induction of semichronic epileptic foci using cobalt oxide.

This paper describes a new method for production of semichronic epileptic foci in the cerebral cortex of cats. Cortical lesions that turned into epileptic foci were induced by extradural application of cobalt oxide powder. These lesions extended through the entire depth of the gray matter, but did not cause gross macroscopic damage. The cobalt oxide powder was removed from the dura mater 7 days after its application, at which time the lesion already showed epileptic activity; this activity did not diminish 7, 14, or 21 days later. Testing of epilepsy was done with a special procedure that allowed work with anesthetized animals. Before treatment with cobalt oxide began, the maximal dose of convulsant drug that would not cause an epileptic electrocorticogram response was determined for each animal (the "trigger dose"). Subsequent testing of potential epileptic foci consisted of monitoring the electrocorticographic responses to rapid intravenous injections of the trigger convulsant dose. The success of the present method in production of epileptic foci is evaluated by several criteria and is compared with other methods.

Surgical control of semichronic epileptic foci in the cat's sensorimotor cortex.

The present work was undertaken in order to find out whether delicate subpial incisions can be used to stop the epileptic activity of cortical lesions induced by cobalt oxide. Epileptic foci were produced in cats by epidural application of cobalt oxide powder. The presence of epilepsy was demonstrated a week later in anesthetized cats by injections of a "trigger dose" of pentamethylenetetrazole. Performance of subpial incisions through the focus area immediately abolished all ongoing epileptic activity. Such activity could not be evoked again by subsequent injection of pentamethylenetetrazole trigger doses throughout a 2-week period. The practical implications of this result are discussed. Some theoretical consequences of the similarity between the response of penicillin foci and that of cobalt oxide foci to the application of subpial incisions were evaluated. Finally, an attempt is made to explain the differences between our results and those produced by other investigators who also attempted to inactivate cobalt lesions in the cortex.

The surgical control of acute epileptic foci in the cat's cerebral cortex.

Topectomy is the treatment of choice for patients suffering from intractable focal epilepsy not responding to pharmacological treatment. A disadvantage of this method is the neurological deficit produced by excision of functional neurons. For this reason the excision of epileptic foci in vital cortical regions is avoided. Thus patients suffering from intractable focal epilepsy in the motor area do not, as yet, have a satisfactory medical or surgical solution to their problem. The purpose of this work is to suggest a different surgical approach on the basis of new data regarding vertical neural connections in the cortex that are vital to the maintenance of the epileptic foci. This possibility has been investigated so far only in acute animal experiments with the intention of applying this method next in chronic animal experiments and then, if successful, in human beings.

Neurosurgical management of the elderly patient.

The records of 59 patients above the age of 65 operated on for diverse neurosurgical problems between January 1975 and September 1976 were reviewed. It was found that in only about half of the cases was the referral diagnosis correct. Most of the referred patients diagnosed as cerebrovascular accident or senile dementia were found to be suffering from intracranial space-occupying lesions or normal pressure hydrocephalus. Post-operatively there was a significant improvement in 48% of this group of geriatric patients, with no change in 23% and a poor result in 29%. when the data on patients with benign lesions were considered separately, it was found that in this group there was a significant improvement in 60%, with no change in 23% and a poor result in only 17%.

Anomalous anterior inferior cerebellar artery simulating intracanalicular acoustic nerve tumor.

A case is described of tinnitus and hearing loss associated with widening of the left internal meatal canal. Surgical exploration revealed a vascular loop adherent to the VIIIth nerve. Release of the adhesions was followed by cessation of the tinnitus and improvement in hearing.

Extraosseous extradural tuberculous granuloma of the cervical spine: a case report and review of intraspinal granulomatous infections.

A 70-year-old woman presented with a 5-month history of tetraparesis. Her cerebrospinal fluid and roentgenographic examination of the cervical spine were both normal. Myelography showed an extradural type of spinal cord compression at the C7 level. At operation, an extraosseous extradural mass of granulation tissue was removed, which proved on histological and bacteriological examination to be a tuberculous granuloma.

Neurosurgical management of single brain metastasis.

A series of 74 consecutive cases undergoing craniotomy for single brain metastasis in the Beilinson Medical Center between October 1975 and October 1981 were reviewed. All patients underwent radiation therapy after craniotomy. The most common metastasis was that of unknown origin (35%), followed by lung (24%) and breast (16%). Overall median survival after craniotomy was 6.6 months. Overall 1- and 2-year survival rates were 30 and 15%, respectively. Operative mortality (30 days) was 15%. For the patients with metastases to the lung, median survival was 7.5 months and 1-year survival rate was 33%. It appears from this report that two dominant factors affect the prognosis of these patients. The first is the long latent interval (time between diagnosis of primary tumor and detection of metastasis). The second is the location of the metastasis; those with lesions in the cerebral hemispheres had a far better outcome than those with cerebellar lesions (p less than 0.0001).

[Outcome of immediate management of severe head injuries].

Immediate management of severe head injuries still poses a serious challenge. 50 patients with severe head injuries (Glasgow Coma Scale, 8 or less) were treated from February 1, 1989 to April 30, 1990. The effects of age, Glasgow Coma Score at admission, CT findings, pupillary reactivity to light and intracranial pressure on outcome, were evaluated. The results of the present series match those of other studies and in some aspects the results are even superior. We attribute the high incidence of good outcome to the direct referral of the severe head injury patients, thus excluding delays at peripheral hospitals. In addition, aggressive management in the intensive care units and a broader range of indications for operation were also correlated with favorable outcome.