Labyrinth and neck reflex modification of the tonic vibration reflex in the decerebrate cat.

The interaction between tonic labyrinth or neck reflexes and the tonic vibration reflex acting on the medial head of triceps in the decerebrate cat is described. Medial triceps was isotonically loaded and reflex actions were measured as changes in muscle length. Natural stimulation of the receptors giving rise to tonic labyrinth or neck reflexes can either enhance or diminish the size of a pre-existing tonic vibration reflex. It is also shown that descending activity from either the labyrinth or neck reflex systems can completely suppress the tonic vibration reflex, whereas the tonic vibration reflex was never observed to suppress an established labyrinth or neck reflex.

Antifibrinolytic agents in subarachnoid haemorrhage.

For many years clinicians have used antifibrinolytic agents to try to reduce rebleeding after subarachnoid haemorrhage. Early studies of their effectiveness produced conflicting results. This paper re-evaluates the available trials and considers benefits in the light of potential complications. Present evidence conclusively demonstrates that epsilon-aminocaproic acid and tranexamic acid administered in standard dosage, reduce the risk of rebleeding but, as a result of an increased incidence of ischaemic complications, do not benefit patients' outcome.

Observer variability in assessing the clinical features of subarachnoid hemorrhage.

Clinical assessment of patients with subarachnoid hemorrhage (SAH) is important both in determining management and in predicting outcome. A previous report showed considerable observer inconsistency when patients were graded with either the Hunt and Hess or the Nishioka system. This study evaluates observer variability in assessment of the individual clinical features from which these grading systems are derived. Assessment of the presence or absence of neck stiffness caused least inter-observer variability. Headache caused most variability, due to difficulty in grading its severity. Determination of the severity of a neurological deficit proved more reliable than deciding whether or not a deficit was present. The terms used to describe the level of consciousness in the Hunt and Hess and Nishioka systems were found to be significantly less consistent than the Glasgow Coma Scale. The authors suggest that when patients with SAH are assessed it is necessary to take into account the consistency with which observers can record a clinical feature, as well as its prognostic importance.

Observer variability in grading patients with subarachnoid hemorrhage.

The management of individual patients with subarachnoid hemorrhage depends greatly on assessment of the patient's clinical condition. Difficulty in applying current grading systems prompted the authors to conduct studies of observer variability and to attempt to identify sources of inconsistency. Observers graded 15 patients by both the Hunt and Hess and Nishioka systems. Considerable observer variability was found, with up to four different grades being selected for the same patient. Kappa statistics were used to evaluate the data. This method determines observer agreement occurring in excess of chance. Kappa values for each grading system showed observer agreement to be significantly better than chance, yet revealed marked observer variation. Most variation occurred when Grade 3 was selected, irrespective of the system used. In a further study where observers graded clinical summaries, similar variation occurred; therefore, inconsistency was due mainly to difficulty in matching patients with levels described in the grading system, rather than to fluctuation in the patient's clinical condition or difference in the observers' examination technique. Variability was high when patients with systemic disease or vasospasm on angiography were graded with the Hunt and Hess system. The studies show that a simpler and more reliable grading system is required, and emphasize and need for caution when interpreting the results from different published series.

Source of fibrin/fibrinogen degradation products in the CSF after subarachnoid hemorrhage.

In 48 patients with a subarachnoid hemorrhage, levels of fibrin/fibrinogen degradation products (FDP's), total protein, and plasminogen were measured in the cerebrospinal fluid (CSF) between Days 9 and 15 after the bleed. Of these 48 patients, 22 received tranexamic acid. Despite a significant reduction in the incidence of rebleeding in patients taking tranexamic acid, no difference in FDP levels was found between patients receiving tranexamic acid and a control group of patients who were not; nor was any relationship evident between FDP levels and rebleeding. In patients with detectable levels of FDP's, CSF protein and plasminogen values were also increased, and FDP's were found more frequently in the CSF of patients with an impaired level of consciousness or with a neurological deficit. These findings suggest that in the 2nd week after subarachnoid hemorrhage, the presence of FDP's in the CSF reflects a damaged blood-CSF barrier rather than ongoing local fibrinolysis in the subarachnoid space. A finding of FDP's in the CSF is, therefore, an unreliable monitor of antifibrinolytic treatment in subarachnoid hemorrhage and cannot be used for selecting patients at high risk of rebleeding.

Outcome of aneurysmal subarachnoid hemorrhage in patients 66 years of age and older.

The outcome at three months after aneurysmal SAH in a group of older patients and a group of younger patients is compared. The patients were admitted within 72 hours of their SAH. Of 61 patients 66 years of age and older, comprising 13% of the whole patient group, 52% died, 12% remained dependent and 36% became independent. In the younger group, 55% had an independent outcome (p less than 0.01). In contrast to what we expected in the older patient group, not extracranial, but intracranial events (re-bleeds, infarcts, hydrocephalus) were by far the most frequent cause of deterioration.

Electrophysiological identification of nerve roots during operations for spinal dysraphism.

A method for identifying conducting nervous tissue within the spinal canal during operations for spinal dysraphism is described. This technique allows safe division of tethering fibrous bands and the filum terminale.

Continuing education: the British experience.

The methods used to assess proficiency in neurosurgical trainees and consultant staff are reviewed. Under the auspice of the Surgical Royal Colleges trainees undergo a formal assessment 6 monthly by their trainer, annually by a local training committee and in their 3rd year of training by the Specialist Advisory Committee (SAC) in Neurosurgery. This committee supervises all neurosurgical training in the UK and Ireland and recommends trainees for the Certificate of Completion of Training if their training assessments and operative experience are satisfactory and if they have passed the Intercollegiate Specialty Examination in Neurosurgery. Assessing proficiency of consultant staff in the UK poses greater difficulty. For several years neurosurgeons have registered Continuing Medical Education (CME) credits on a voluntary basis. Such action is insufficient to reassure the public of professional competence. The General Medical Council (GMC) have submitted proposals for revalidation based on- (i) the maintenance of a 'folder' including details of performance, CME and complaints, (ii) annual appraisals carried out internally, (iii) a 5 yearly external assessment which if satisfactory would lead to revalidation by the GMC. Team working will be encouraged and consultants made responsible for the quality of service of their professional colleagues. A national comparative audit of subarachnoid haemorrhage should permit comparison of outcomes between neurosurgical units.

Spontaneous resolution of a colloid cyst of the third ventricle.

We report a case of an asymptomatic colloid cyst of the third ventricle in a 35-year-old male, which on follow-up MRI at 15 months appears to have spontaneously resolved. To our knowledge, this is the first such case reported and supports the role of conservative management of small asymptomatic colloid cysts.

Findings of the International Subarachnoid Aneurysm Trial and the National Study of Subarachnoid Haemorrhage in context.

Concern has been expressed about the applicability of the findings of the International Subarachnoid Aneurysm Trial (ISAT) with respect to the relative effects on outcome of coiling and clipping. It has been suggested that the findings of the National Study of Subarachnoid Haemorrhage may have greater relevance for neurosurgical practice. The objective of this paper was to interpret the findings of these two studies in the context of differences in their study populations, design, execution and analysis. Because of differences in design and analysis, the findings of the two studies are not directly comparable. The ISAT analysed all randomized patients by intention-to-treat, including some who did not undergo a repair, and obtained the primary outcome for 99% of participants. The National Study only analysed participants who underwent clipping or coiling, according to the method of repair, and obtained the primary outcome for 91% of participants. Time to repair was also considered differently in the two studies. The comparison between coiling and clipping was susceptible to confounding in the National Study, but not in the ISAT. The two study populations differed to some extent, but inspection of these differences does not support the view that coiling was applied inappropriately in the National Study. Therefore, there are many reasons why the two studies estimated different sizes of effect. The possibility that there were real, systematic differences in practice between the ISAT and the National Study cannot be ruled out, but such explanations must be seen in the context of other explanations relating to chance, differences in design or analysis, or confounding.

Distant extradural haematoma complicating removal of frontal tumours.

The authors report two patients who developed occipito-parietal extradural haematomas following removal of large frontal meningiomas. In both, CT scanning aided diagnosis and subsequent management. Although rare, this complication should be considered when patients deteriorate or fail to improve after removal of frontally situated tumours or inexplicable brain swelling is encountered at the time of original surgery.

Treatment of acute hydrocephalus after subarachnoid hemorrhage with serial lumbar puncture.

Computed tomography demonstrated acute hydrocephalus less than or equal to 72 hours after subarachnoid hemorrhage in 24 (23%) of 104 patients. Of these 24 patients, six (25%) had no impairment of consciousness. In nine (11%) of the remaining 80 patients, acute hydrocephalus developed within 1 week after subarachnoid hemorrhage. With the exception of three patients, all 104 patients received antifibrinolytic treatment. Delayed clinical deterioration from acute hydrocephalus occurred in seven (29%) of the 24 patients with acute hydrocephalus on admission and in six (8%) of the remaining 80 patients. Serial lumbar puncture was performed in 17 patients. Twelve (71%) of the 17 patients treated with serial lumbar puncture, including 10 (77%) of the 13 patients with delayed deterioration from acute hydrocephalus after admission, achieved improvement in the level of consciousness. Four of these 17 patients (4% of all 104 patients) required an internal shunt. No patient deteriorated from coning following serial lumbar puncture. The rebleeding rate within 12 days after subarachnoid hemorrhage in hydrocephalic patients with serial lumbar puncture was not higher than the rate in those without hydrocephalus (two [12%] of 17 versus nine [13%] of 71). Neither meningitis nor ventriculitis was observed. We conclude that if neither a hematoma with a mass effect nor an obstructive element exists, cerebrospinal fluid drainage with serial lumbar puncture is a good alternative to ventricular drainage in patients with acute hydrocephalus after subarachnoid hemorrhage.

Differences in the management of ruptured intracranial aneurysms: a survey of practice amongst British neurosurgeons.

British consultant neurosurgeons in post for at least one year were sent a postal questionnaire about the way in which they managed patients with ruptured aneurysms; 87% replied. Wide differences were evident in almost all aspects of treatment, before, during and after surgery. A consensus of opinion appeared in only a few areas: the employment of magnification during surgery, the use of clipping as the preferred method of surgical treatment, and a general reluctance to operate on patients with a depressed conscious level within a week of haemorrhage.