Spinal blastomycosis--case report.
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Blastomycosis↗
Biomedical subjects
L Symon
Publications and source records attributed to L Symon.
An experimental study of acute subarachnoid haemorrhage in baboons: changes in cerebral blood volume, blood flow, electrical activity and water content.
Subarachnoid haemorrhage following transection of the posterior artery was produced in 10 baboons. Cerebral blood volume (CBV) decreased transiently after subarachnoid haemorrhage. Two basic patterns of intracranial pressure (ICP) were observed; in one ICP returned to normal but in the other it remained elevated. In this latter group four out of five animals showed an increase in CBV above the original level. There were delays in sensory conduction (measured using somatosensory evoked potentials) bilaterally; those on the contralateral side to the bleed were correlated with ICP whereas other factors are implicated on the ipsilateral side. Initial flow reduction and restoration of cerebral blood flow were both correlated with water content.
Animals↗
Clinical use of a portable bedside cerebral blood flow machine in the management of aneurysmal subarachnoid hemorrhage.
Recent advances in electronics and microprocessors have enabled the development of a compact portable cerebral blood flow (CBF) machine capable of being transported to the patient's bedside. We have used such a device, the Novo Cerebrograph 2a, during the past 7 months on a regular basis in the day to day management of our patients with intracranial aneurysms. One hundred three studies were performed in 23 cases of suspected intracranial aneurysm. Twenty-two cases presented with acute subarachnoid hemorrhage. Patients were studied on admission, preoperatively, in the recovery room, on postoperative Days 1, 5, and 14, and whenever the clinical condition of the patient warranted. The preoperative admission grade was found to correlate well with the mean CBFisi (ISI: initial slope index). Grade III and IV patients had flows significantly lower than those of Grade I and II patients. Serial CBF measurements proved useful in the management of 18 of 22 cases admitted with acute subarachnoid hemorrhage. Delayed ischemic deficits secondary to vasospasm occurred in 6 cases, with a concomitant average fail in mean flow in the symptomatic hemispheres of 27.9%. After volume expansion, an average increase in flow of 29.7% was noted. Low preoperative flows influenced management decision-making in 8 cases. In a further 4 cases, serial CBF measurements were helpful in the differential diagnosis of new neurological signs.
Adult↗
Dural arteriovenous malformations of the spine. Clinical features and surgical results in 55 cases.
The clinical and angiographic findings of 55 patients with a spinal dural arteriovenous malformation (AVM) are reviewed, and the results of surgery assessed. The symptoms of dural AVM are usually gradual in onset, and hemorrhage from this type of AVM is less common than in true spinal cord angiomas. Other clinical features and the myelographic findings are similar to those of spinal cord angiomas. On angiography, the nidus of dural AVM's usually projected lateral to the spinal cord. Clipping of communicating vessels between the AVM and the coronal plexus was carried out in 50 patients, and decompressive laminectomy only in five cases. Surgery led to improvement of disturbed gait or arrest of a previously progressive course in 85% of those managed by clipping communicating vessels. The pathophysiology and surgical treatment of dural AVM's are discussed.
Adult↗
Somatosensory evoked potential monitoring during the management of aneurysmal SAH.
Somatosensory evoked responses to median nerve stimulation have been recorded during the management of subarachnoid hemorrhage from intracranial aneurysms. The type of measurement was central conduction time (CCT), the time interval between the N14 peak (at C-2) and the N20 peak (at the cortex). Significant differences were found between patients with aneurysms in clinical Grade 4 and normal individuals, although there was no significant difference between most aneurysm patients in Grades 1 through 3. The prolongation of CCT was found of prognostic value. Significant prolongation (mean plus two standard deviations) from the normal period of 5.4 +/- 0.4 msec was found significantly useful to predict a less than satisfactory outcome (a patient with neurological signs or disabled) at 2 months, and these differences were detectable as early as 48 hours postoperatively. Differences between conduction time in the two hemispheres could also be used prognostically, although the significance of the differences did not appear until 48 to 72 hours after surgery, and was in any event less than that of CCT.
Adult↗
Perioperative use of somatosensory evoked responses in aneurysm surgery.
Somatosensory evoked potentials have been recorded during 34 operations for intracranial aneurysm. The central conduction time (CCT), the time between the N14 peak (recorded at C-2) and the N20 peak (recorded at the cortex) in response to median nerve stimulation, has been found to be increased by administration of halothane, by brain retraction, and by temporary vascular occlusion in some instances. Increase of CCT to more than 10 msec, or disappearance of the response was associated in two cases with postoperative neurological deficit, neither permanent. In a further case, prolongation of CCT was used as a guide to the repositioning of an imperfectly placed clip on a middle cerebral artery aneurysm. The value of the technique as a perioperative monitoring system is discussed.
Adolescent↗
Cavernous hemangioma of the optic canal. Report of two cases.
Cavernous hemangioma is the most frequent orbital tumor in adults. It has so far not been described in an intracanalicular situation. Two such cases recently encountered are presented, and the literature is reviewed. The clinical, radiological, neurophysiological, surgical, and pathological findings from the two cases are described.
Adult↗
Surgical management of suprasellar meningioma. Part 1: The influence of tumor size, duration of symptoms, and microsurgery on surgical outcome in 101 consecutive cases.
A consecutive series of 101 cases of suprasellar meningioma has been reviewed. Most of the patients were between 40 and 60 years of age, and women predominated in all age groups. Visual impairment was the most common admitting complaint and visual field defect the most common finding. Symmetrical visual field defects were noted in 22 cases, while the remaining 79 cases had either asymmetrical binocular involvement or only monocular defects. All patients underwent craniotomy with the operating microscope being used in 33 cases. Mortality and partial resection rates were lower and overall outcome was better in patients with tumors 3 cm or less in size and a duration of symptoms of 2 years or less. Use of the operating microscope also appeared to lower the mortality rate and improve the overall outcome; however, no effect on postoperative visual improvement was noted.
Adult↗
Surgical management of suprasellar meningioma. Part 2: Prognosis for visual function following craniotomy.
Visual outcome in 101 consecutive cases of suprasellar meningioma treated over a 35-year period has been examined. Preoperative visual loss was evaluated using a scoring system that takes both visual acuity and visual fields into account. In this way a percentage visual loss was calculated for each patient before and after surgery. The effects on visual outcome of age, preoperative visual loss, duration of visual symptoms, tumor size, status of the optic disc, and binocular versus monocular involvement was examined. For the group as a whole, vision improved in 63 patients, was unchanged in 12 patients, and was worse in 24 patients. Prognosis was favorably affected by a mean duration of symptoms of less than 2 years, a tumor size of less than 3 cm, a preoperative visual loss of less than 50%, and the presence of normal optic discs on funduscopic examination. Age had some effect on prognosis, but the presence of binocular or monocular involvement had no effect.
Adult↗
Surgical experiences with giant intracranial aneurysms.
A series of 35 patients with 36 giant aneurysms is presented. Thirteen patients presented following subarachnoid hemorrhage (SAH) and 22 with evidence of a space-occupying lesion without recent SAH. The preferred technique of temporary trapping of the aneurysm, evacuation of the contained thrombus, and occlusion of the neck by a suitable clip is described. The danger of attempted ligation in atheromatous vessels is stressed. Intraoperatively, blood pressure was adjusted to keep the general brain circulation within autoregulatory limits. Direct occlusion of the aneurysm was possible in over 80% of the cases. The mortality rate was 8% in 36 operations. Six percent of patients had a poor result. Considerable improvement in visual loss was evident in six of seven patients in whom this was a presenting feature, and in four of seven with disturbed eye movements.
Adolescent↗
The results of anterior cervical fusion in cervical spondylosis. Review of 125 cases.
A retrospective study of 125 patients with cervical spondylosis with, in the main, myelographic features, and treated by the anterior cervical route (Cloward's operation) is presented. Patients were selected for this type of surgery as opposed to the posterior approach, on clinical and radiological grounds which are described. Results of this treatment have generally been good and this is particularly so in very elderly patients with a single lesion at C 3/4. There is a group of patients in whom the disease process seems to progress despite surgery.
Adult↗
Microsurgery of the hypothalamus with special reference to craniopharyngioma.
After a short survey of microanatomy, microtopography, neurophysiology and neuropathophysiology of the hypothalamus the surgical approaches to the hypothalamus with special reference to the craniopharyngiomas are described in detail. Based on 100 personal cases (1954-1979) the special procedure, depending on the site and extent of the tumour and its involvement of the hypothalamus, is discussed. Primary radical excision (19 cases) with a mortality rate of 10.5% seems to be the method of choice, as late mortality recurrences and secondary operations are frequent after non-radical procedures. Modern microsurgical technique promises to achieve primary radical excision more frequently and with less risk.
Cerebral Angiography↗
Post-traumatic syringomyelia: the results of surgery.
Between 1973 and 1982 twenty-seven patients with post-traumatic syringomyelia had operations performed to drain the cyst. Three types of operation were performed, cord transection, tube syringostomy to the sub-arachnoid space and tube syringostomy to the peritoneal cavity. Five patients developed proven blockage of their catheters. The results are presented. Pain was dramatically and gratifyingly improved in 14 patients. Motor power showed the most consistent improvement in 14 patients. Only eight patients showed the most consistent improvement in 14 patients. Only eight patients showed sensory improvement; this was the least likely to improve. The progress of the condition could be arrested in the majority of cases, but a small number continued to deteriorate and required further operations.
Adult↗
An experimental study of the acute stage of subarachnoid hemorrhage.
A baboon model of subarachnoid hemorrhage (SAH) has been developed to study the changes in cerebral blood flow (CBF), intracranial pressure (ICP), and cerebral edema associated with the acute stage of SAH. In this model, hemorrhage was caused by avulsion of the posterior communicating artery via a periorbital approach, with the orbit sealed and ICP restored to normal before SAH was produced. Local CBF was measured in six sites in the two hemispheres, and ICP monitored by an implanted extradural transducer. Following sacrifice of the animal, the effect of the induced SAH on ICP, CBF, autoregulation, and CO2 reactivity in the two hemispheres was assessed. Brain water measurements were also made in areas of gray and white matter corresponding to areas of blood flow measurements, and also in the deep nuclei. Two principal patterns of ICP change were found following SAH; one group of animals showed a return to baseline ICP quite quickly and the other maintained high ICP for over an hour. The CBF was reduced after SAH to nearly 20% of control values in all areas, and all areas showed impaired autoregulation. Variable changes in CO2 reactivity were evident, but on the side of the hemorrhage CO2 reactivity was predominantly reduced. Differential increase in pressure lasting for over 7 minutes was evident soon after SAH on the side of the ruptured vessel. There was a significant increase of water in all areas, and in cortex and deep nuclei as compared to control animals.
Acute Disease↗
Haemorrhage in pituitary tumours.
Evidence of haemorrhage was found in 58 of 320 verified pituitary adenomas (18.1%). Haemorrhage occurred as acute or subacute apoplexy and recent or old silent haemorrhages. The differentiation was based on the predominant clinical features, the operative findings and the length of the history. There was a relatively high incidence of giant or large recurrent adenomas, invasiveness, malignant change, increased vascularity and sinusoidal characteristics on histology among the haemorrhagic tumours. The majority (53.4%) were hypopituitary but 39.6% had no obvious endocrine defect. CT scan has helped in the early preoperative diagnosis of haemorrhage in pituitary adenoma. Transcranial surgery appeared a most effective mode of treatment in the current series.
Adenoma↗
Perspectives in aneurysm surgery.
The natural history of aneurysm surgery is briefly reviewed and an assessment made of the place of surgical, radiological and physical advances in the management of aneurysms over the past twenty years. Over this time, there has been a steady reduction in management mortality, particularly associated with the introduction of the operating microscope, and with an increased understanding of the pathophysiology of ischaemic brain.
Humans↗
Calcium ions and calcium antagonists in ischaemia.
The effects of a calcium antagonist, nimodipine, were tested on the response of the cerebral circulation to arterial pCO2 and blood pressure changes. The effects of reduced blood flow upon oedema formation and extracellular ion homeostasis under nimodipine preloading were studied. Both open and closed skull primate models were used, with alpha-chloralose anaesthesia. Nimodipine infusion increased basal blood flow in the open skull, but not the closed skull animals. Autoregulation to increased blood pressure was little affected. Responses to arterial pCO2 changes and autoregulation to reduced blood pressure were severely impaired. Residual blood flow after middle cerebral artery occlusion was significantly higher with nimodipine than in controls. The threshold levels of blood flow for the development of cortical oedema and for disturbance of ion homeostasis were, however, increased, suggesting that nimodipine interferes with cellular energy metabolism and increases the susceptibility of tissue to ischaemic damage.
Animals↗
Kinetics of resolution of transient increases in extracellular potassium activity: relationships to regional blood flow in primate cerebral cortex.
Previous studies have established that in cerebral cortex subjected to progressive reduction in blood flow, two distinct thresholds of flow may be identified below which cellular function is impaired: the cortical evoked response loses amplitude when local flow falls below 18ml/100gm/min, and below 11ml/100gm/min a major increase in extracellular K+ activity (Ke) occurs. However, further evidence suggests that even at higher flows the capacity of the tissue to handle induced ionic changes may be impaired. To investigate this point, we studied the kinetics of resolution of Ke following a transient increase produced by local electrical stimulation, in relation to the local pre-stimulus flow (reduced by acute middle cerebral artery occlusion) in baboons. Flow was measured by the hydrogen clearance method and Ke by ion-exchanger micro-electrodes, in the same cortical regions. In primary induced transients (those increases in Ke elicited by cortical stimulation, and reported previously,) Ke attained a maximum value of 8-10 mM and then decayed towards the 4-mM baseline. The half-time of this decay was significantly increased from normal in the flow range 20-40 ml/100 gm/min, and increased further at lower flows until, below 11ml/100gm/min, Ke clearance was undetectable. Thus, cortical ion homeostasis appeared impaired at flows substantially closer to normal than those thresholds mentioned above, a result discussed in terms of impairment of active Ke clearance mechanisms. Secondary induced transients arose during a primary induced transient, reaching considerably higher peak values (8-30 mM) of Ke (indicating temporary clearance loss) and with slower decay rate than the primary. Spontaneous transients, not associated with any stimulus, were also observed; like secondary transients, they occurred only at flows below 20ml/100gm/min and showed a reduction in clearance rate with progressive ischemia. They resemble spreading depression and their generation is discussed in terms of the ionic and metabolic conditions at their time of origin.
Animals↗