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Biomedical subjects

W M Mueller

Publications and source records attributed to W M Mueller.

27 records · Page 2Linked to original sources
PubMed1995

Surgical management of lumbar neuropathic spinal arthropathy (Charcot joint) after traumatic thoracic paraplegia: report of two cases.

Two cases of successful surgical treatment of neuropathic spinal arthropathy (Charcot joint) are reported. Each patient was first seen several years after traumatic paraplegia. One patient had progressive kyphosis and the other had severe pain. Symptoms were relieved in both patients after interbody fusion and posterior fixation by using the lateral extracavitary approach to the spine. Both patients remain symptom free several years after the surgery. Fusion should be performed in symptomatic patients with neuropathic spinal arthropathy: this can be combined with posterior fixation in a single stage by using the lateral extra-cavitary approach.

Adult↗
PubMed1994

Functional magnetic resonance imaging of somatosensory stimulation.

Functional magnetic resonance imaging (FMRI) has detected changes in regional cerebral blood flow and volume in response to motor movements, visual stimuli, and auditory stimuli in each of their respective primary cortices. This experiment was conducted to determine whether signal changes in the somatosensory cortex secondary to tactile stimulation could be demonstrated. The palm of the right hand was periodically stimulated while the subject was undergoing echo-planar imaging with a 1.5-T magnetic resonance scanner equipped with local gradient and radio frequency coils. Sagittal and coronal images of 10- to 15-mm slice thickness were selected to include the postcentral gyrus and surrounding regions. Temporally correlated signal changes of 1% to 5% occurred in the peri-rolandic region in each of six subjects. The time course of signal changes was comparable to that found in other primary sensory and motor cortices. The results provide preliminary evidence of the sensitivity of FMRI to activation of the somatosensory cortex with tactile stimulation and support FMRI as a promising noninvasive technique for study of the functional organization and integrity of the cerebrum.

Adult↗
PubMed1993

Intrathecal baclofen for severe spasticity secondary to spinal cord injury.

OBJECTIVE: To evaluate the use of intrathecal baclofen for the treatment of muscle spasticity in patients with spinal cord injury. DATA SOURCES: A MEDLINE search was used to identify relevant and pertinent literature. Information was obtained from open-label clinical trials, abstracts, conference proceedings, and review articles. Index terms in the search included baclofen, spasticity, intrathecal drug infusion, spinal cord disease, and neurosurgery. DATA EXTRACTION: Studies were selected for review if they evaluated intrathecal baclofen in patients with spinal cord injury. Emphasis was placed on human studies published in the English language. Trials were reviewed by dosage regimen, therapeutic response, adverse effects, and complications. DATA SYNTHESIS: Thus far, intrathecal baclofen administration shows promise in the treatment of spasticity resulting from spinal cord trauma. Few complications and adverse effects have been reported. CONCLUSIONS: Muscle spasms and spasticity constitute a significant problem in spinal cord injuries, interfering with rehabilitation and leading to inconveniences and complications in these patients. Oral baclofen is the drug of choice for spasticity due to spinal cord trauma. It often is ineffective, however, because of the large dosages required to cross the blood-brain barrier and the subsequent appearance of central nervous system adverse effects. These adverse effects are not tolerated by many patients. Intrathecally administered baclofen has been approved by the Food and Drug Administration (FDA) for the treatment of spasticity in patients with spinal cord injury who are refractory to or cannot tolerate oral baclofen. It is intended for use only in implantable pumps approved by the FDA for the administration of baclofen into the intrathecal space. Intrathecal administration achieves high concentrations in the spinal cord with small dosages, thus reducing the incidence of central nervous system adverse effects. To date, approximately 350 patients with spinal cord injury have been treated with intrathecal baclofen. Reductions in spasticity have been demonstrated in both open-label and placebo-controlled trials. Patients also often make substantial gains in activities of daily living. Few adverse effects and complications have been reported. However, tolerance to the clinical effects of intrathecal baclofen has been reported. Further studies are needed to determine specific patient populations that may benefit most from intrathecal baclofen administration. Individual dosage ranges and follow-up care also need to be defined more completely. In addition, the question of whether tolerance detracts from long-term clinical benefits with intrathecal baclofen needs to be addressed.

Baclofen↗
PubMed1993

Functional magnetic resonance imaging of complex human movements.

Functional magnetic resonance imaging (FMRI) is a new, noninvasive imaging tool thought to measure changes related to regional cerebral blood flow (rCBF). Previous FMRI studies have demonstrated functional changes within the primary cerebral cortex in response to simple activation tasks, but it is unknown whether FMRI can also detect changes within the nonprimary cortex in response to complex mental activities. We therefore scanned six right-handed healthy subjects while they performed self-paced simple and complex finger movements with the right and left hands. Some subjects also performed the tasks at a fixed rate (2 Hz) or imagined performing the complex task. Functional changes occurred (1) in the contralateral primary motor cortex during simple, self-paced movements; (2) in the contralateral (and occasionally ipsilateral) primary motor cortex, the supplementary motor area (SMA), the premotor cortex of both hemispheres, and the contralateral somatosensory cortex during complex, self-paced movements; (3) with less intensity during paced movements, presumably due to the slower movement rates associated with the paced (relative to self-paced) condition; and (4) in the SMA and, to a lesser degree, the premotor cortex during imagined complex movements. These preliminary results are consistent with hierarchical models of voluntary motor control.

Adult↗
PubMed1988

Dysphagia associated with cervical spine disorders: pathologic relationship?

Three cases of dysphagia in patients with large anterior cervical osteophytes are discussed. Although all three showed mechanical obstruction thought to be secondary to the bone growth, only one patient reported significant relief of the dysphagia after resection of the growths. The spinal etiologies of dysphagia and the operative results are discussed.

Aged↗
PubMedDate not supplied

Functional magnetic resonance imaging in partial epilepsy.

Functional magnetic resonance imaging (FMRI) detects signal changes in brain that accompany regional changes in neuronal activity. In normal human brain, FMRI shows changes in signal in the postcentral gyrus or superior temporal gyrus that correlate with voluntary motor activity or language processing, respectively. The model used to explain the changes in signal linked temporally with cerebral activity is a reduction in cerebral capillary deoxyhemoglobin concentration due to the increased blood flow that accompanies neuronal activity in the cerebrum. FMRI has been used in normal subjects but not extensively in patients. To determine the feasibility of using FMRI to map cerebral functions in patients with partial epilepsy syndromes, we performed a pilot study, using FMRI to identify signal changes in motor and language areas in response to tasks that activate those areas. Signal changes in epilepsy patients approximated those observed in volunteers. We conclude that FMRI can be developed as a method for functional cerebral mapping in partial epilepsies.

Adult↗
PubMedDate not supplied

Location of the sensorimotor cortex: functional and conventional MR compared.

PURPOSE: To determine the value of functional MR imaging to supplement conventional MR imaging for locating the rolandic cortex. METHODS: Parasagittal MR images acquired in conjunction with functional MR images were reviewed. The central sulcus was identified on the MR images by conventional parcellation methods. In the functional MR images, the sensorimotor cortex (rolandic cortex) was identified by the activation secondary to finger and thumb movement or tactile stimulation of the palm. The location of the central sulcus and rolandic cortex was compared. RESULTS: In 18 of 23 studies, the central sulcus selected by anatomic criteria coincided exactly or approximately with the cortex activated by the motor or sensory tasks. In two cases of tumor, the rolandic cortex could be located by means of the activation, but the central sulcus was not identified because of severe distortion of anatomic landmarks. In two volunteers, the central sulcus identified by anatomic landmarks did not coincide with the activated cortex. CONCLUSION: This study demonstrates that functional imaging supplements anatomic imaging in locating the sensorimotor cortex. Functional MR imaging may be a useful adjunct to conventional MR imaging to determine noninvasively the proximity of eloquent brain to focal brain lesions.

Adult↗