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Biomedical subjects

R C Dauser

Publications and source records attributed to R C Dauser.

27 records · Page 2Linked to original sources

Symptomatic Chiari I malformation in childhood: a report of 7 cases.

The Chiari I malformation, once thought to be a disorder of clinical importance only in the teen years and beyond, is now recognized as being significant in the pediatric population as well. We have reviewed 7 cases of Chiari I malformation in children less than 12 years of age. Hydrosyringomyelia was often, but not invariably, an accompanying feature, and this in turn was associated with scoliosis and motor weakness. All patients had posterior fossa and cervical decompression with dural grafting procedures, as well as various types of syringosubarachnoid shunts placed. Intraoperative ultrasound was found to be a valuable surgical adjunct. Symptoms and signs were improved or stabilized in all patients. We feel that this disorder is now more commonly reported in young children because of the increased availability of noninvasive neuroimaging techniques, especially magnetic resonance imaging. Questions are raised as to the actual incidence of undiscovered cases of this disorder in children with commonly seen conditions such as scoliosis.

Arnold-Chiari Malformation↗

Management of post-traumatic cervical spine instability: operative fusion versus halo vest immobilization. Analysis of 49 cases.

A 5-year retrospective analysis was conducted for all cervical spine fractures associated with neurologic deficit initially treated at the University of Michigan Hospitals. Forty-nine cases of lower cervical spine fracture (C3-C7) were reviewed. Twenty-eight patients underwent early operative fusion followed by immobilization with either halo vests, or hard cervical collars, and 20 patients were initially immobilized in halo vests only. One patient refused treatment and was kept in a hard cervical collar. The average period of immobilization was 3 months. Eight patients in the halo vest group demonstrated radiographic evidence of spinal instability following immobilization (40%). Five of these eight patients subsequently required operative stabilization. Two of these five suffered progression of neurologic deficit secondary to loss of reduction while immobilized. Spinal instability occurred in two of the 28 patients initially fused (7%) (p less than 0.01), and in the patient treated in a collar. The findings indicate: 1) the halo vest does not protect patients with cervical instability from neurological injury, nor does it absolutely immobilize the cervical spine; 2) surgery may be required to provide spinal stability, even after a 3-month orthotic treatment period; and 3) there appears to be an increased rate of spinal stability with fusion and immobilization versus immobilization alone.

Adolescent↗

Evaluation of hydrocephalus shunts in the emergency room.

The workup of suspected shunt malfunction requires consideration of several factors, including history, physical and neurologic examinations, and appropriate laboratory and radiologic tests. Hydrocephalus is a benign condition, often compatible with normal neurologic function if properly controlled. It is therefore vital that patients with hydrocephalus have their shunts carefully maintained to avoid serious complications due to shunt obstruction and infection. By following the guidelines listed above, most shunt problems can be detected and appropriate consultation arranged.

Cerebrospinal Fluid Shunts↗

The orthograde flow of tritiated proline in corticospinal neurons at various ages and after spinal cord injury.

The amount of radioactive proline which reaches the cervical cord by axoplasmic flow after intracortical injection of label is higher in rapidly growing 3 to 6 week old rats but becomes relatively constant in unoperated control rats beyond age 10 weeks. In adult rats with spinal cord transection at T-8, however, the amount of tritiated proline detected in the cervical cord above the site of transection is markedly increased five weeks after surgery, falls to more normal levels by 14 weeks after surgery, and is significantly below normal at 25 weeks after surgery. These findings are consistent with abortive attempts to regenerate axons at five weeks after injury. Twenty-five weeks after injury neuronal death and loss of both cells and axons which would normally project to the caudal cord through the site of spinal cord transection result in a decrease in the axon label found in the cervical region. Recognition of this variability in the amount of radioactivity that reaches the cervical region after spinal cord injury forced a reconsideration of previously reported evidence for regeneration in spinal cord transected animals receiving no specific postoperative therapy. There is no evidence for regeneration in such untreated transected rats.

Animals↗

Symptomatic congenital spinal stenosis in a child.

A case of congenital lumbar stenosis producing lower extremity spasticity and bladder dysfunction in a young child is presented. Myelography demonstrated a marked stenosis of the spinal canal at L-2, L-3, and decompressive laminectomy resulted in a marked improvement in symptoms. A discussion of lumbar stenosis in general illustrates that is is extremely rare for this condition to become symptomatic during childhood. The literature on congenital lumbar stenosis is reviewed.

Adolescent↗

Spinal cord regeneration in rats made immunologically unresponsive to CNS antigens.

Seventy days after complete spinal cord transection, both treated and untreated rats showed evidence that some corticospinal axons had regenerated. Rats made immunologically unresponsive to CNS tissue showed no increase in corticospinal regeneration as measured by orthograde axoplasmic flow of tritated proline or retrograde axoplasmic labelling with horeseradish peroxidase. However, treated rats did demonstrate electrophysiological evidence of regeneration of long ascending sensory pathways. Tolerant animals additionally treated with cyclophosphamide showed corticospinal axonal regeneration by tritated proline transport and electrophysiological techniques and also showed electrophysiological evidence of ascending sensory tract regeneration.

Afferent Pathways↗

Analysis of 153 patients with myelomeningocele or spinal lipoma reoperated upon for a tethered cord. Presentation, management and outcome.

After primary repair of myelomeningoceles or lipomyelomeningoceles, late progressive neurologic deterioration commonly occurs due to a treatable cause. In our experience many of these patients have a tethered cord. With early untethering, most patients are stabilized and a significant percent of the patients show improvement in their clinical status. Of 341 tethered cord releases done from 1981 to 1988, we report on 153 patients reoperated upon following primary repair. One hundred were performed after primary closure of a myelomeningocele and 53 after repair of a lipomyelomeningocele. The average age of the patients with a myelomeningocele was 6 years old, and for the spinal lipoma patients, 8 years old. The presenting symptoms were similar; weakness, deterioration in gait, scoliosis, orthopedic deformities, and urinary incontinence represented the most common complaints. All 153 patients were noted to have a tethered cord at operation. Additional pathology (dermoid tumors, hydromyelia, tight filum and diastematomyelia) was present in 30% of the cases. With the use of the CO2 laser for dissection, all but 10 patients could be untethered. Follow-up over an average of 4 years revealed 93% of the patients with a myelomeningocele had stabilization or improvement of their presenting complaints, and 7% had progression of their presenting complaints. All of the lipomyelomeningocele patients had either stabilization or improvement of their presenting complaints. There were no mortalities. Close follow-up and early treatment of this patient population is indicated. With release of the cord a significant portion of the population will have relief or improvement of their presenting complaints.

Adolescent↗