PubMed Health⌕ Search

Biomedical subjects

K G Davies

Publications and source records attributed to K G Davies.

At least 19 recordsLinked to original sources
PubMed1996

Relationship of hippocampal sclerosis to duration and age of onset of epilepsy, and childhood febrile seizures in temporal lobectomy patients.

Controversy exists as to whether hippocampal sclerosis (HS) is a preexisting cause or a consequence of seizures. We investigated 122 consecutive patients who underwent anterior temporal lobectomy for intractable epilepsy between 1989 and 1992. MRI scans were normal apart from evidence of HS in 5 cases. The degree of HS was graded from 0 to 4. There was a significant inverse correlation between age of seizure onset and grade of HS (P < 0.0001), and a positive correlation between duration of epilepsy and grade of HS (P < 0.001). Using a dichotomous grouping of HS (HPSC - for grades 0 and 1 [no/mild HS], and HPSC + for grades 3 and 4 [moderate/marked HS]), there was a positive correlation between HPSC + and a history of childhood febrile seizures (CFS) (P = 0.003), earlier age of onset of epilepsy (P < 0.001) and longer duration of epilepsy (P < 0.001). There was no correlation with history of particularly prolonged individual seizures. Partial correlations after controlling for age at onset of epilepsy showed that there was no longer a significant relationship between HPSC + and duration of epilepsy. After controlling for duration of epilepsy, the relationship between HPSC + and age of onset remained significant (P < 0.001). The correlation between HPSC + and CFS, controlling for age at onset, was not significant. A series of logistic regression analyses showed age at onset to be the only predictor of HPSC +. It is concluded that this is supportive evidence for preexisting HS being a cause of temporal lobe epilepsy and not a consequence of seizures.

Adult↗
PubMed1996

MRI confirmation of accuracy of freehand placement of mesial temporal lobe depth electrodes in the investigation of intractable epilepsy.

Stereotactic techniques are commonly used to place intracerebral depth electrodes. We placed 15 depth electrodes (9R, 6L) freehand, orthogonally into temporal lobes in 12 patients undergoing monitoring with subdural strip electrodes in the evaluation of their intractable epilepsy. Coronal MRI was performed with the electrodes in place. The mean distance from the closest depth electrode contact to the hippocampus was 0.8 mm (range 0-5 mm). In 11 instances the closest contact was either within or making contact with the hippocampus, and in another three it was within 3 mm. For 13 electrodes, the most distal contact was the closest to the hippocampus, for two the penultimate contact was closest. There were no complications from electrode placement. Ictal onset was mesial temporal in 11 patients and frontal in one. Temporal onset was detectable in the depth electrode in each case, usually simultaneously with the onset in the subdural electrode although often the discharge was better developed in the depth electrode. We conclude that freehand placement of depth electrodes orthogonally into the temporal lobe can achieve a degree of accuracy sufficient to localize seizure onset in the mesial temporal lobe.

Adolescent↗
PubMed1996

Relation between intracarotid amobarbital memory asymmetry scores and hippocampal sclerosis in patients undergoing anterior temporal lobe resections.

The intracarotid amobarbital procedure (IAP) is used to evaluate memory function preoperatively in candidates for anterior temporal lobe resections (ATL). We examined IAP memory asymmetry scores in 30 patients undergoing ATL (17 R, 13 L), as a function of the presence (HS+) or absence (HS-) of hippocampal sclerosis. Ictal onset zones were determined by extraoperative recording with subdural strip electrodes in all but 3 patients in whom magnetic resonance imaging (MRI) scan showed HS. MRI scans were otherwise normal. All patients were left hemisphere dominant for language except 1, in whom language was represented bilaterally. IAP memory testing involved presentation of eight subjects during anesthesia of each hemisphere, followed by recognition testing after patients recovered from amobarbital effects. A score of 1 was given for each correctly recognized object, and 0.5 was deducted for each false-positive identification. There were 16 foils. A total asymmetry score was calculated, which was positive if there was agreement between the direction of the symmetry and side of operation and negative if reversed. The mean asymmetry score for HS- (n = 8) was 0.9; that for HS+ (n = 22) was 4.1 (p < 0.01). IAP memory performance provided lateralizing information (asymmetry score > or = + or -2) in 73% of cases; among these, the lateralization was correct in 91%. Our data indicate that IAP memory asymmetry predicts both laterality of ictal onset and the presence of HS.

Adolescent↗
PubMed1995

Surgery for intractable epilepsy secondary to viral encephalitis.

In a series of 668 craniotomy cases for intractable epilepsy, in 11 patients (1.6%) the presumed aetiology was a previous episode of viral encephalitis, a widespread cerebral inflammation, which may therefore produce multifocal epilepsy. Seven patients had chronic ictal electrocorticography (ECoG). Two of these had a generalized onset, one bilateral temporal independent onset, and four unilateral mesial temporal onset. Three patients underwent corpus callosotomy. Eight had resections (seven anterior temporal lobectomy (ATL), and one ATL and frontal resection). Pathology was hippocampal sclerosis in four, neocortical gliosis in three and one specimen was normal. Of the resection patients, three (37%) were seizure-free at a mean of 3 years postoperatively and three (37%) unchanged. It is concluded that where the aetiology of intractable epilepsy is viral encephalitis the possibility of multifocal epilepsy should be considered. Chronic ECoG is recommended. Nevertheless, unilateral hippocampal sclerosis can also be produced and the results of ATL in these cases can be rewarding.

Adult↗
PubMed1995

Type I Chiari deformity presenting with profound sinus bradycardia: case report and literature review.

Type I Chiari deformity presents with diverse symptoms and signs which can be attributed to compression of structures at the foramen magnum. Bradycardia as a result of medullary compression has not been reported previously. A patient is described with type I Chiari deformity who presented with episodic profound sinus bradycardia for which a pacemaker was inserted before the diagnosis of cerebellar ectopia was finally made. Surgical decompression proved curative.

Arnold-Chiari Malformation↗
PubMed1995

Language function after temporal lobectomy without stimulation mapping of cortical function.

We studied 95 patients who underwent standard anterior temporal lobectomy (ATL) without stimulation mapping of language areas, using neuropsychological parameters of language function preoperatively and 1 year postoperatively [Boston Naming Test and Verbal Fluency, and the Information, Comprehension, Arithmetic, Similarities, Digit Span, and Vocabulary subtests of the Wechsler Adult Intelligence Scale (WAIS)]. Verbal IQ (VIQ), Performance IQ (PIQ), Full-Scale IQ (FSIQ), and Verbal Deviation Quotient were also evaluated, as were parameters of memory function. All patients had hemisphere dominance for language assessed by an intracarotid amytal test. Fifty-three patients had a left dominant (LHDL) ATL with a mean extent of lateral resection of 4.8 cm, and 10 had a left ATL with right or mixed hemisphere dominance (RHDL, MDL). Thirty-two patients had a right nondominant ATL. Seizure outcome was 57 and 59% seizure-free for LHDH and right nondominant group, respectively, 1 year after operation. Comparison of preoperative scores showed the LHDL group to have significantly lower scores than the right nondominant group for several parameters of language function and memory. The group undergoing left dominant ATL showed no significant loss of language function postoperatively and actually showed gains in many parameters. Standard ATL without stimulation mapping of language areas and with conservative lateral resection is safe for long-term language function. In addition, evidence shows preexisting language dysfunction in patients undergoing left dominant ATL.

Adolescent↗
PubMed1995

Results of cortical resection for intractable epilepsy using intra-operative corticography without chronic intracranial recording.

Twenty-four patients with intractable partial epilepsy underwent surgery between 1969 and 1988. Localization was by non-invasive means using scalp EEG and CT. In 12 cases the focus was temporal and in eight frontal. Craniotomy was undertaken with intraoperative electrocorticography (ECoG). Ten cases had a standard temporal lobectomy, seven a topectomy, four topectomy with tumour excision and one tumour excision alone. Two cases did not have a resection. Pathology revealed a mass lesion in 12 cases, hippocampal sclerosis in two and gliosis in six. Mean length of follow-up was 7.4 was. Fourteen patients (64%) were seizure free, two (9%) almost seizure free, four (18%) had worthwhile improvement and two (9%) no improvement. Of the temporal resections, 9 out of 12 (75%) were seizure free and of the extratemporal resections 5 out of 10 (50%) were seizure free. Removal of a mass lesion carried the most favourable prognosis for seizure outcome: 10 our of 12 (83%) of the cases with mass lesions, but 3 out of 6 (50%) of the cases with gliosis were seizure free. In two of the frontal resections removal of tumour resulted in disappearance of contralateral frontal independent spikes. It is concluded that where sufficient information exists to localize seizure activity by non-invasive means, invasive recording is unnecessary. The utility of intraoperative ECoG is discussed. It may be of limited use in cases of standard resection of when a mass lesion is present, but ECoG can prove useful to delineate the epileptogenic area in cases where there is o mass lesion and the results can still be rewarding.

Adolescent↗
PubMed1995

Intracerebral haemorrhage due to amphetamine abuse: report of two cases with underlying arteriovenous malformations.

Amphetamine abuse may be complicated by intracerebral, subdural or subarachnoid haemorrhage. The causative mechanism is probably a combination of vasculitis and induced hypertension. Most cases of intracerebral haemorrhage are subcortical. Only one case of amphetamine-induced intracerebral haematoma where there was also an underlying arteriovenous malformation has been previously reported. We report two cases of intracerebral haematoma due to amphetamine abuse whether an underlying AVM was found at the time of surgery. This possibility should be considered in cases of amphetamine-induced intracerebral haemorrhage.

Adult↗
PubMed1994

Language function following subdural grid-directed temporal lobectomy.

The purpose of the study was to determine the extent to which a temporal resection may be undertaken without producing risk to temporal language areas. Patients undergoing craniotomy and placement of a subdural electrode array (SEA) for evaluation of intractable epilepsy were studied to determine the variability of distance of temporal language cortex from the temporal pole. Hemisphere dominance was determined by intracarotid sodium amytal injection. Temporal lobe speech arrest (SA) was mapped with a 64 contact point SEA. Thirty-one patients had left dominant hemisphere SEAs. Thirty had SA 5 cm to 9 cm from the temporal pole (median 7 cm). One had SA at 3 cm. Twenty-one patients subsequently had temporal lobectomy (TL). Mean extent of resection was 5.7 cm (range 3 to 9 cm). In 18 TL patients who had neuropsychometric evaluation of language function pre- and post-surgery, there was no significant deterioration. Thirty-nine patients had right non-dominant SEAs placed. Eighteen had TL. Thirteen of these had pre- and post-surgery language evaluation and there was no significant change. Comparison of preoperative scores showed significant superiority of the right non-dominant group over the left dominant group for naming. TL up to 5 cm without stimulation mapping of language areas would be safe in the majority of cases, but one subject (3%) had SA mapped anterior to this and a small number of cases may therefore be at risk to language function following a 5 cm TL. Extensive lateral resections up to 9 cm are possible with preservation of language function with stimulation cortical mapping.

Adolescent↗
PubMed1994

Twenty-year survival following excision of primary CNS lymphoma without radiation therapy: case report.

The prognosis of primary central nervous system lymphoma (PCL) is very poor with a mean survival of 3-6 months without treatment and 15-45 months following radiation therapy. PCL is very sensitive to radiation therapy, but recurrence is frequent. A response of the tumour to steroids has also been documented. This report describes a patient who had surgery for a solitary PCL without subsequent radiation therapy or steroid medication and who had no evidence of tumour recurrence 16 years later. He remains well 20 years after surgery. No case of long-term survival following surgery alone for PCL has been reported previously. Surgical excision may have a place in the management of solitary PCL.

Aged↗
PubMed1994

Idiopathic spinal extradural lipomatosis in a non-obese otherwise healthy man.

Spinal extradural lipomatosis is rare and is usually associated with long-term steroid administration or obesity. It is most commonly thoracic in situation. We present a unique case of spinal extradural lipomatosis in a 20-year-old non-obese, clinically normal man. The role of MRI in investigation and the management options are discussed.

Adult↗
PubMed1994

Pleomorphic xanthoastrocytoma--report of four cases, with MRI scan appearances and literature review.

Pleomorphic xanthoastrocytoma (PXA) is a rare glial tumour typically occurring in young patients in the first three decades, having a superficial cortical location and with a relatively good prognosis for long-term survival. Four cases are reviewed. The magnetic resonance imaging (MRI) appearances, which in PXA have been reported only once before, are described in three cases. The fourth case was studied by computed tomography and angiography. One patient developed seizures at age 2 days and was aged 2 1/2 years at presentation. This is the youngest patient with PXA yet reported. Three of the four patients had seizures, but in one case the tumour was not the cause of the seizures. Review of the literature has revealed 47 reported cases. Mean age at presentation was 14.3 years. Epilepsy occurred in 78%. Seventeen patients were alive without recurrence at a mean of 7.9 years after diagnosis and 10 patients died at a mean of 7.4 years after diagnosis. Thirteen cases had recurrence at a mean of 6 years after surgery and in five instances the recurrence was in the form of a glioblastoma. Resections which were grossly total were less likely to develop recurrence than those which were subtotal. Complete gross resection of tumour offers the best therapeutic option in PXA.

Adolescent↗
PubMed1993

Temporal lobectomy for intractable epilepsy: experience with 58 cases over 21 years.

Sixty patients with intractable complex partial seizures underwent surgery between 1969 and 1990, and 58 of these underwent a temporal resection. Of 39 patients who had chronic subdural electrocorticography (ECoG) 37 subsequently underwent an anterior temporal lobectomy (ATL) and two had the electrodes removed without resection. Two patients had bilateral depth electrodes placed and then had an ATL. Fourteen patients with evidence of temporal structural lesions had temporal resections with intraoperative ECoG and five had resection without ECoG. Mean length of follow-up for all patients was 6 years. Fifty-five per cent of cases were seizure-free postoperatively, 7% almost seizure-free, 21% had worthwhile improvement and 17% no improvement. The outcome for patients with structural lesions was particularly good. Nine patients complained of mild memory impairment postoperatively and one had a severe amnestic problem. One patient with an unsuspected tumour developed a hemiparesis and dysphasia. One other patient had persistent dysphasia. No mortality was attributable to the surgery. It is concluded that ATL is an excellent operation for the treatment of intractable epilepsy arising from the temporal lobe and chronic subdural ECoG is a safe and reliable method for localizing the seizure origin.

Adolescent↗
PubMed1993

Cortical resections for intractable epilepsy of extratemporal origin: experience with seventeen cases over eleven years.

Seventeen patients underwent surgery between 1981 and 1990 for intractable partial epilepsy arising outside the temporal lobe. Twelve had frontal seizure onset, two parietal, two occipital and one diffusely in the hemisphere. Localization was achieved using extraoperative electrocorticography (ECoG) in five cases and intraoperative ECoG was employed in 12. Fifteen patients underwent cortical resections, but two did not subsequently have a resection. Both of these had porencephalic cysts. Of the 15 who had resections six (40%) were seizure free after a mean of 7.3 years. One (7%) was almost seizure free, six (40%) had worthwhile improvement. Pathological examination revealed oligodendroglioma in three, recurrent meningioma in one, vascular malformations in two, glial hamartoma in one and gliosis in six. One case with gliosis initially was shown to have an underlying malignant astrocytoma 2 years later. All these patients had CT abnormalities prior to surgery. Two patients (13%) had no worthwhile improvement. Pathology in these two was ischaemic neurons and arachnoid thickening. Both had normal CT findings preoperatively. One patient had an increased hemiparesis postoperatively. There were three cases of postoperative infection. It is concluded that extratemporal resection can achieve good results for seizure control and intraoperative ECoG is an effective technique for localizing the epileptogenic area. The presence of a structural lesion carries a particularly favourable prognosis for seizure outcome and surgery should, therefore, be strongly considered in patients with intractable partial epilepsy who have evidence of underlying structural pathology.

Adolescent↗
PubMed1993

Hemispherectomy for intractable seizures: long-term results in 17 patients followed for up to 38 years.

Seventeen patients who underwent hemispherectomy for intractable epilepsy between 1950 and 1971 were reviewed to evaluate outcome for seizure control and the development of late complications. Sixteen had complete resection and in one the frontal pole was preserved. The follow-up period was 19 to 38 years (mean 28 years). One patient was lost to follow-up review 10 years after surgery. Three patients had died but none of the deaths were related to the surgery or to epilepsy. Ten patients had no postoperative complications, and three developed late complications: two had elevated intracranial pressure with enlargement of the remaining lateral ventricle after 13 and 16 years, and one had recurrent bleeding into the cerebrospinal fluid after 6 years. All were treated surgically and have since remained well. Eight patients (47%) had no seizures after surgery and eight (47%) were almost seizure-free. It is concluded that classical hemispherectomy is an effective operation for control of some types of epilepsy. The late complications, which occurred in 17% of the cases in this series, can be successfully treated. This series presents the longest follow-up results after hemispherectomy reported to date.

Adolescent↗
PubMed1992

Acute spontaneous spinal epidural haematoma with temporary resolution.

A case of acute spontaneous spinal epidural haematoma is presented which underwent resolution of symptoms and signs before relapsing again hours later. Cases of spontaneous remission of this condition have been reported but not subsequent relapse. Conservative management of apparently resolving cases may therefore be inappropriate.

Acute Disease↗
PubMed1990

Childhood extradural haematomas, not always obvious.

Extradural haematomas in children are rare, but they may occur following a trivial head injury. We report a case where, following an unrecognised head injury to a three-year-old child, the insidious non-specific presentation of the extradural haematoma led to delay in the diagnosis and treatment.

Child, Preschool↗