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Biomedical subjects

R E Maxwell

Publications and source records attributed to R E Maxwell.

At least 19 recordsLinked to original sources
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

Cyclosporine A toxicity presenting with acute cerebellar edema and brainstem compression. Case report.

A 38-year-old man receiving cyclosporine A after bilateral lung transplantation for cystic fibrosis presented with cortical blindness, generalized seizures, and cerebellar edema. Progressive brainstem compression necessitated emergency posterior fossa decompression. Replacement of cyclosporine A with an alternative immunosuppressive agent, FK506, was followed by rapid neurological recovery and dramatic resolution of radiographic abnormalities. The etiology, clinical features, and radiographic findings of cyclosporine A neurotoxicity are discussed. The pertinent literature is reviewed.

Acute Disease↗
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

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↗
PubMed1991

The prognostic value of residual spikes in the postexcision electrocorticogram after temporal lobectomy.

We correlated the postresection electrocorticograms (ECoGs) of 80 patients who underwent temporal lobectomy under general anesthesia for treatment of intractable complex partial seizures with surgical results in three groups: seizure/aura free (32 patients), auras only (16 patients), and one or more postoperative seizures (32 patients) at mean follow-up times of 34, 31, and 38 months, respectively. Spontaneous "residual spikes," ie, present after all resections, were present in 47% of patients who had no postoperative seizures or auras. However, they occurred in 72% of patients with any postoperative seizures (p less than 0.05). The location (convexity, mesial, or edge of resections) or the distribution (unifocal versus multifocal) of the residual spikes was not of prognostic value. Quantitative studies in 5-minute epochs of the postexcision ECoGs did not reveal a significant difference in the morphology of the residual spikes, ie, the amplitude or firing pattern (single versus polyspike), in the three groups. The group with postoperative seizures showed a higher number of spikes per epoch (greater than or equal to 50), but it was not significant. Although the study shows that patients with residual spikes may have good prognosis, they are at significantly higher risk for postoperative seizures as compared with those without residual spikes. The possibility that intensity of firing of residual spikes may be an additional predictor of outcome warrants further study.

Cerebral Cortex↗
PubMed1987

Magnetic resonance imaging in the assessment and surgical management of epilepsy and functional neurological disorders.

Magnetic resonance imaging (MRI) offers significant advantages over computerized tomography (CT) and teleradiographic techniques when used for the evaluation and management of epilepsy and functional neurological disorders. Depth recording and radiofrequency electrodes can be more accurately positioned within structures such as the amygdala and hippocampus. The extent of corpus callosum section, lobectomy, topectomy, and radiofrequency stereotactic lesions can now be readily confirmed and related with seizure, neurological, and behavioral outcome. Occult, usually low grade, intraparenchymal neoplasms not visualized on CT scans can be located by MRI and biopsied or excised by MRI stereotactic techniques.

Corpus Callosum↗
PubMed1987

Neuroschisis of the cervical spinal cord in a patient with Klippel-Feil syndrome.

During the neurological work-up of a young patient with Klippel-Feil syndrome, the presence of a neuroschisis of the cervical spinal cord was detected. The patient presented with a transient and acute hemisensory loss and a Horner's syndrome of the opposite side. The unusual presentation and radiological findings in a patient with Klippel-Feil syndrome prompted this report.

Adult↗
PubMed1986

Intrathecal morphine during lumbar spine operation for postoperative pain control.

The analgesic requirements and bladder function of 5 patients who received 1 mg of intrathecal morphine during lumbar spine operation are compared to those of 10 control patients. No analgesics were used by the treatment group for the first 24 hours postoperatively. The test group subsequently required twice the amount of analgesics during the 2nd through 5th days after operation compared to controls. All 5 patients who received intrathecal morphine developed urinary retention for 24 to 36 hours. The brief duration of analgesia, the increased narcotic use after the effects of the morphine dissipated, and urinary retention after a single intraoperative dose of intrathecal morphine suggest caution in using this technique.

Adult↗
PubMed1985

Klippel-Feil syndrome in children: clinical features and management.

A retrospective analysis of 11 children with the diagnosis of Klippel-Feil syndrome treated at the University of Minnesota Hospital over a period of 20 years is presented. The salient features of the syndrome and its associated anomalies are reviewed. Emphasis is placed on its neurological aspects, particularly the potential risks of injury to the craniocervical junction and cervical spine. Guidelines for the management of these patients are suggested.

Adolescent↗
PubMed1985

Stereotactic removal of a migrating ventricular catheter.

Retained ventricular catheters are usually well tolerated but, when infection is present, their removal becomes imperative because such catheters serve as a nidus for persistent infection. Minimally invasive methods for the removal of retained catheters are desirable. The removal of an infected, retained, subcortical ventricular catheter using stereotactic techniques is described. The authors think that this method is a safe and effective first step in dealing with this difficult problem.

Catheters, Indwelling↗
PubMed1984

Surgical management of torticollis.

Torticollis is a clinical sign of either CNS or musculoskeletal dysfunction. Thorough clinical and neuroradiographic evaluation is indicated for determination of the source, course, and exact nature of the deformity before a considered approach to surgical management is undertaken. Torticollis of neurogenic origin is managed by surgical decompression of the brainstem or cervical spinal cord when indicated, as in the presence of hydrocephalus, the Arnold-Chiari malformation, syringobulbia , syringomyelia, colloid cyst of the third ventricle, or neoplasms in the third ventricle, posterior fossa, or cervicomedullary junction. In progressive and medically refractory cases of spasmodic torticollis, neuroablative procedures, neuroaugmentive procedures, selective muscle excisions, and radical cervical muscle excisions have been used to control the dystonia. Torticollis of musculoskeletal origin is often secondary to or associated with trauma, although congenital craniocervical anomalies may be a predisposing factor. The primary goals of surgery for craniovertebral or upper cervical spine deformity are reduction of the malalignment; decompression of the brainstem, cervical spinal cord, and/or nerve roots if necessary; and stabilization of the upper cervical spine.

Arnold-Chiari Malformation↗
PubMed1984

Identification and management of high-risk patients with Klippel-Feil syndrome.

Patients with Klippel-Feil syndrome are often at high risk for neurological injury. The cervicomedullary junction and cervical spinal cord are especially vulnerable. Twenty-one patients examined and treated over a 20-year period are reviewed. The salient features of the syndrome are identified, and an approach to management is proposed.

Adolescent↗
PubMed1983

Some comparative effects of gemfibrozil, clofibrate, bezafibrate, cholestyramine and compactin on sterol metabolism in rats.

Liver cholesterogenesis in rats was measured by giving [l-14C]octanoate i.p.; 1 h later digitonin-precipitable sterols were isolated and counted. In rats fed normal chow and given 7 daily p.o. doses of compounds and then fasted, at 20 h after the last dose, clofibrate or bezafibrate had no effect at lower doses or inhibited incorporation at higher doses, while compactin or gemfibrozil caused increases; cholestyramine added to the diet also caused marked increases. When rats were fed chow containing 0.1% cholesterol and 5.5% peanut oil, again at 20 h following the last of 7 daily doses, gemfibrozil caused increases of incorporation which diminished at higher levels of dosage, while clofibrate caused only inhibition. A single dose of gemfibrozil caused inhibition at 3 h postdose followed by increases over control at 36 and 48 h; a single dose of compactin caused inhibition at 3 h but not subsequent increase, and a single dose of clofibrate had no effect over the entire period. In rats fed chow containing 1.5% cholesterol and 5.5% peanut oil, gemfibrozil given orally or cholestyramine in the diet prevented the diet-induced decreases of plasma HDL cholesterol and increases of liver cholesterol content, while bezafibrate treatment did not have those effects. The effects of cholestyramine rapidly disappeared when it was withdrawn from the diet, while the effects of gemfibrozil persisted after dosage was stopped. These results suggest that some of the actions of gemfibrozil on rat sterol metabolism are quantitatively different from those of the other agents tested.

Animals↗
PubMed1983

Phenylenebis(oxy)bis[2,2-dimethylpentanoic acid]s: agents that elevate high-density lipoproteins.

A series of phenylenebis(oxy)bis[2,2-dimethylpentanoic acid]s have been synthesized and evaluated as potential hypolipidemic agents. Compound 18 (CI-924) was found to be the most potent compound in this series. In rats, compound 18 not only reduced low-density lipoprotein cholesterol but also increased high-density lipoprotein (HDL) cholesterol. Comparative studies in rats indicated 18 produced an equal elevation of HDL cholesterol at one-third of the dose required of gemfibrozil. Structure-activity relationships are discussed.

Animals↗
PubMed1983

Clinical evaluation of a depth electroencephalography electrode.

Stereo depth electroencephalography (EEG) is of proven benefit in lateralizing and localizing seizure origin in select cases of epilepsy. There are potential hazards and technical considerations inherent with depth EEG, however, that have limited the general applicability of this technique. A new depth EEG electrode with materials and design features that facilitate safe insertion and artifact-free recording has been developed. The design features and technique for inserting the electrode are described. The electrode was evaluated during 2600 hours of implantation and recording in seven patients. With the use of stereotactic techniques, the electrode could be positioned accurately within precise anatomical landmarks such as the amygdaloid nucleus and the hippocampus. After insertion, no hemorrhage or edema was detected along the electrode tracts by third generation computed tomographic scanning. There was no evidence of pyrogenicity or infection. Electrode migration was not observed. A large electrical field could be sampled because of the relatively large surface of the cylindrical depth electrode contacts.

Electrodes, Implanted↗
PubMed1983

Concussion incidences and severity in secondary school varsity football players.

The head coaches and players of 103 secondary school football teams in Minnesota were asked to respond to mail questionnaires. Information about injury incidence and concomitant health care provision was elicited. Responses from 3,063 players (81 per cent) yielded a total injury rate of 78 injuries/100 players; 19/100 players reported a concussion experience characterized by loss of consciousness and/or loss of awareness. Of the players who experienced a loss of consciousness, 69 per cent were returned to play the same day. Persistent concussion symptoms were reported as long as six to nine months following the end of the season; six cases involved permanent disabilities. Continued use of illegal techniques of butt-blocking and face-tackling by as many as 40 per cent of the players was associated with apparent increased risks of concussions and concussion symptoms. Players with a prior history of loss of consciousness had a risk of loss of consciousness four times that of the player without a prior history.

Athletic Injuries↗