Striking problems with imbalance concerning basic prognostic variables were observed in spite of the large population studied. These imbalances concerned pretreatment hypotension, pretreatment hypoxia, and the incidence of epidural hematomas. In future trials of pharmacological therapy for severe head injury, serious consideration must be given to alternative randomization strategies. Given the heterogeneous nature of head injury and the identification of populations that do relatively well with standard therapy, target populations with a higher risk for mortality and morbidity may be more suitable for clinical trials of such agents.

We performed a retrospective study of 2484 consecutive patients with mild head injury (Glasgow Coma Scale score 13-15) who were seen during a period of 18 months. Of these, 2351 (94.6%) patients scored 15 points, 88 (3.5%) scored 14 points and 45 (1.3%) 13 points. A multivariate analysis showed that advanced age, a lower GCS (13-14) and the presence of skull fracture, and focal signs, significantly increased the incidence of abnormal computed tomography (CT) findings. By contrast, the gender, the mechanism of injury, the occurrence of initial loss of consciousness, posttraumatic amnesia and coagulation disorders did not significantly increase the incidence of abnormal CT findings. Patients with 13-14 GCS had a significantly higher incidence of initial loss of consciousness, of skull fracture, abnormal CT findings, need for hospital admission, delayed neurological deterioration and need for operation than patients with a GCS of 15. Thus, we suggest separating patients with a GCS of 13-14 into a different category and recommend performing CT in all those not improving within 4-6 h of injury. Such a policy makes skull radiography unnecessary in this subgroup. By contrast, skull radiographs may be useful for the triage of patients with a GCS of 15 that represent most of the mild head injury cases; radiographs should be obtained in patients presenting with initial loss of consciousness or posttraumatic amnesia (27.9% of the total cases) as these two findings were associated with a significantly higher incidence of fracture. Patients without these two findings (72.1% of the cases) showed a very low incidence of skull fracture (0.9% in this study) and may be discharged home with a warning sheet.

The authors undertook a follow-up study of 286 patients who underwent surgical treatment for intracranial meningioma between 1973 and 1994, in order to analyse clinical, radiological, topographic, histopathological and therapeutic factors significantly influencing tumour recurrence. All patients were followed by using either computed tomography (CT) or magnetic resonance from 3 months to 17 years since first surgery (mean follow-up: 4.1 years). Forty-four (15.4%) recurrences were detected during this time period. Overall recurrence rates were 14%, 37% and 61% at 5, 10 and 15 years, respectively. Factors significantly associated with tumour relapse in bivariate analysis were: tumour location at petroclival and parasagittal (middle third) regions, incomplete surgical resection (assessed by Simpson's classification), atypical and malignant histological types (WHO classification), presence of nucleolar prominence, presence of more than 2 mitosis per 10 high-power fields, and heterogeneous tumour contrast enhancement on the CT scan. The multivariate analysis using the Cox's proportional hazards model identified the following risk factors for recurrence: incomplete surgical resection (Relative risk: 2.2; 95% Confidence interval: 1.33-3.64), non conventional histological type (RR: 2.13; 95%CI: 1-4.53), heterogeneous contrast enhancement on the CT scan (RR: 2.25; 95%CI: 1.1-4.72) and presence of more than 2 mitosis per 10 high-power fields (RR: 2.28; 95%CI: 0.99-5.27). Patients without any of these features showed low recurrence rates (4% and 18% at 5 and 10 years), and thus, they need less clinical and radiological controls through the follow-up than patients with some of these risk factors.

The clinical, radiological, and histopathological features of 21 cases of angiographically occult intracranial vascular malformations (AOIVM's) are analyzed, and a review of 241 additional appropriately documented, histologically verified cases collected from the literature is presented. In all, there were 115 (43.8%) arteriovenous malformations, 82 (31.2%) cavernous angiomas, 26 (9.9%) venous angiomas, 10 (3.8%) cases of capillary telangiectasis, and 29 (11%) mixed or unclassified angiomas. The result of the analysis shows that there are no essential differences in the patterns of clinical presentation, the computerized tomography (CT) appearance, or the surgical prognosis among these pathological types of vascular malformations. Certain histological features common to all AOIVM's (such as the small caliber, the more or less complete thrombosis of the malformed vessels, and the changes induced in the surrounding brain tissue by repeated microhemorrhages) seem to determine the biological behavior of the anomaly rather than the predominant type of vessel involved. Thus, subdivision of AOIVM's into the four classical pathological types has little practical value. Most AOIVM's are visualized by the CT scan and show a rather typical appearance. Surgical removal, which prevents rebleeding and ameliorates or suppresses seizure activity, is usually easy to perform and represents the treatment of choice for patients with clinically symptomatic AOIVM's.

Most hemangiopericytomas (HPCs) are located in the musculoskeletal system and the skin, while the intracranial location is rare. They represent 2 to 4% in large series of meningeal tumours, thus accounting for less than 1% of all intracranial tumours. Many authors have argued about the true origin of this tumour. The current World Health Organization classification of Central Nervous System tumours distinguishes HPC as an entity of its own, and classified it into the group of "mesenchymal, non-meningothelial tumours". Radical surgery is the treatment of choice, but must be completed with postoperative radiotherapy, which has proved to be the therapy most strongly related to the final prognosis. HPCs have a relentless tendency for local recurrence and metastases outside the central nervous system which can appear even many years after diagnosis and adequate treatment of the primary tumour. Twelve patients with intracranial HPC were treated at our Unit between 1978 and 1999. There were 10 women and 2 men. Ten tumours were supratentorial and most located at frontoparietal parasagittal level. The most common manner of presentation was a focal motor deficit. All tumours were hyperdense in the basal Computed Tomography scans and most enhanced homogeneously following intravenous contrast injection. In 50% of cases, tumour margins were irregular or lobulated. Seven tumours were studied with Magnetic Resonance Imaging, being six of them iso-intense with the cortical gray matter on T1-weighted and T2-weighted images. Twenty operations were performed in the 12 patients. In 10 cases radical excision could be achieved with no operative mortality. Total recurrence rate was 33.3%. Eight patients were treated with external radiotherapy at some time through the course of their disease. Eight out of the 12 patients in this series are disease-free (Glasgow Outcome Scale categories 1 and 2) after a mean follow up of 52 months.

The authors report 144 cases of trigeminal neuralgia treated by percutaneous microcompression of the trigeminal ganglion (PMTG). The operation was performed under short-lasting barbiturate anesthesia without endotracheal intubation. Meckel's cave was cannulated with a No. 4 Fogarty catheter and the balloon was inflated for 1 minute. The average intraluminal pressure required for adequate compression of the ganglion was about 1200 mm Hg. All patients were initially relieved of their neuralgia. In a follow-up period ranging from 6 months to 4 1/2 years, 14 patients (9.7%) developed recurrence of pain between 10 and 35 months after surgery. Eleven patients underwent a second PMTG. All nine early failures and 10 of the 11 late recurrences occurred in cases with technical deficiencies. Most of the minor surgical complications observed were also related to avoidable technical errors. There were no anesthetic complications and no deaths. All patients developed mild to moderate postoperative hemifacial numbness with or without objective hypesthesia. Both subjective and objective deficits gradually diminished with time and were well tolerated. One year after the operation nearly 40% of the patients still had patches of slightly decreased sensation in one or more trigeminal divisions and 16% had mild dysesthesia. Anesthesia dolorosa or keratitis was not reported. The PMTG procedure is easy to perform and requires a short operative time and a brief period of hospitalization. It is well tolerated by patients, who describe it as a totally pain-free experience. Morbidity is minimal and recurrence of neuralgia does not seem to be higher than with alternative procedures.

The clinical and computed tomographic (CT) findings in a series of 161 consecutive patients operated upon for postraumatic extradural hematoma are analyzed. Thirteen (8%) patients had delayed epidural hematoma formation. The overall mortality for the series was 12%, significantly lower than that observed during the prior "angiographic" period at the same unit (30%). Because all but 1 of the deaths occurred among the 66 patients unconscious at the time of operation (27% mortality in this subgroup), the authors sought differential factors between comatose and noncomatose patients at operation. There were no significant differences between these groups in age, sex, mechanism of injury, preoperative course of consciousness (lucid interval or not), or epidural hematoma location and shape. In contrast, significant differences were seen between the two subgroups in trauma-to-operation interval, hematoma volume, CT hematoma density (mixed low-high CT density vs. homogeneous hyperdensity), midline displacement, severity of associated intracranial lesions, and postoperative intracranial pressure (ICP). Patients comatose at operation usually evidenced a more rapid clinical deterioration (a shorter trauma-to-operation interval) and tended to have a large hematoma volume, a higher incidence of mixed CT density clot (hyperacute bleeding), more marked shift of midline structures, more severe associated lesions, and higher postoperative ICP levels.

Age and clinical grade on admission are the most important factors influencing the final outcome of patients suffering aneurysmal SAH. A reappraisal of the WFNS grading scale should be considered as no significant differences in outcome were found between some of its grades.