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Biomedical subjects

C L Nash

Publications and source records attributed to C L Nash.

43 records · Page 3Linked to original sources
PubMedDate not supplied

Current status of spinal cord monitoring.

Spinal cord monitoring, as currently practiced, requires a source of sensory stimulus, transmitted through filters and amplifiers, to result in an enhanced signal, which is recorded and studied. Three techniques are under investigation. In one, the stimulation and responses are recorded directly from the dura. In another, the stimulus is applied to a peripheral nerve and the response is gathered from vertebral bone. The third utilizes responses in the form of cortical evoked potentials, with the stimulus applied to peripheral nerves.

Cerebral Cortex↗
PubMedDate not supplied

Transoral microsurgical odontoid resection and spinal cord monitoring.

Four patients underwent transoral resection of the odontoid with utilization of microsurgical technique and spinal cord monitoring of somatosensory cortical evoked responses. All patients improved following surgery, and no operative morbidity or mortality was encountered. Spinal cord monitoring enhances the safety of the procedure and, reapplied at a later date, detects information of prognostic value.

Cerebral Cortex↗
PubMedDate not supplied

In vivo effects of axial loading on double-curve scoliotic spines.

The in vivo three-dimensional orientation of the vertebral columns in five adolescent idiopathic scoliotic subjects with double curves were examined in standing, supine, and supine positions with Cotrel traction postures using a biplanar radiographic technique. This analysis was compared with that obtained from a previous study on five healthy adolescent subjects to assess the postural changes and mechanical factors relating to the development of double-curve scoliotic deformity. Statistical analysis of vertebral orientation, rotation, disc distraction, and wedging between the normal and scoliotic subjects indicated that central intervertebral disc height and anteroposterior wedging were most consistently altered in double-curve scoliotic deformity. Since these two parameters relate directly to the geometry of the disc, the etiology of double-curve scoliosis may be related to a primary defect affecting the geometry of the intervertebral disc that results in a vertebral column which then undergoes rotational deformity.

Adolescent↗
PubMedDate not supplied

In vivo effects of axial loading on healthy, adolescent spines.

Five healthy adolescents were studied using a three-dimensional radiographic technique to analyze the in vivo effects of standing, supine and supine Cotrel traction positioning on the orientation of spinal segments. In general the configuration of these spines was found to be relatively unaffected by changes in subject position and column loading. The major effects of supine positioning appeared to be lessening of standing lumbar lordosis while supine traction tended to diminish this effect. Measurement of rotation relative to a common reference body, L4, was influenced by the degree of AP and ML wedging throughout the column. The standing curve was found to be slightly rotated by a small but constant amount at each level and tended to derotate as a whole with supine and supine traction positioning. Measurement of successive intervertebral rotation showed effects independent of wedging with each vertebral body randomly rotated and unaffected by subject orientation. With the exception of central vertebral disk heights, all parameters measured possessed relatively wide limits of variability which appeared to be the result of true intersubject scatter as opposed to measurement error.

Adolescent↗
PubMedDate not supplied

Spinal cord monitoring during operative treatment of the spine.

Twenty-six orthopedic and 8 neurosurgical patients undergoing spine surgery had spinal cord monitoring before, during, and after operation using somatosensory, averaged cortical evoked responses. Although no inherent risks were apparent in the technical application of this form of spinal cord monitoring, there are limitations that have yet to be evaluated. Classically, somatosensory evoked responses have been considered a function of the posterior columns; however, the results of these studies indicate that more than the function of the dorsal columns alone can be evaluated with this technique. In addition, much remains to be learned regarding the changes in signals noted and the corresponding clinical conditions. Techniques more sophisticated than visual evaluation of response patterns must be established and more sophisticated methods of analysis must be developed. Despite the need for more knowledge of the nature of this system and the correlation between evoked responses and clinical conditions, the system has proved to be effective and to have great potential for improving spine and spinal cord surgery.

Adolescent↗