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Biomedical subjects

P P Sun

Publications and source records attributed to P P Sun.

8 recordsLinked to original sources

Cervical spinal stenosis and sports-related cervical cord neurapraxia in children.

STUDY DESIGN: Congenital spinal stenosis has been demonstrated to contribute to cervical cord neurapraxia after cervical spinal cord injury in adult athletes. A sagittal canal diameter <14 mm and/or a Torg ratio (sagittal diameter of the spinal canal: midcervical sagittal vertebral body diameter) of <0.8 are indicative of significant cervical spinal stenosis. Although sports-related cervical spine injuries are common in children, the role of congenital cervical stenosis in the etiology of these injuries remains unclear. OBJECTIVES: The authors measured the sagittal canal diameter and the Torg ratio in children presenting with cervical cord neurapraxia resulting from sports-related cervical spinal cord injuries to determine the presence of congenital spinal stenosis. METHODS: A total of 13 children (9 male, 4 female) presented with cervical cord neurapraxia after a sports-related cervical spinal cord injury. Age ranged from 7 to 15 years (mean +/- SD, 11.5 +/- 2.7 years). The sports involved were football (n = 4), wrestling (n = 2), hockey (n = 2), and soccer, gymnastics, baseball, kickball, and pogosticking (n = 1 each). Lateral cervical spine radiographs were used to determine the sagittal canal diameter and the Torg ratio at C4. RESULTS: The sagittal canal diameter (mean +/- SD, 17.58 +/- 1.63 mm) and the Torg ratio (mean +/- SD, 1.20 +/- 0.24) were normal in all of these children. CONCLUSION: Using the sagittal canal diameter and the Torg ratio as a measurement of congenital spinal stenosis, the authors did not find evidence of congenital cervical spinal stenosis in a group of children with sports-related cervical spinal cord neurapraxia. The occurrence of cervical cord neurapraxia in pediatric patients can be attributed to the mobility of the pediatric spine rather than to congenital cervical spinal stenosis.

Adolescent↗

Complete spontaneous resolution of childhood Chiari I malformation and associated syringomyelia.

The diagnosis of Chiari I malformation and associated syringomyelia is often made in childhood. Since the advent of magnetic resonance imaging, these abnormalities are increasingly detected incidentally. Despite incomplete understanding of the natural history of asymptomatic Chiari I malformations, the current recommendation is to consider prophylactic surgical intervention in those with an associated syringomyelia. This case report presents a complete spontaneous resolution of a Chiari I malformation and syringomyelia in a child. It illustrates the possibility that asymptomatic children with Chiari I malformations and syringomyelia may be followed conservatively.

Adolescent↗

Surgically treated lumbar disc disease in the pediatric population: an outcome study.

OBJECT: This outcome study was undertaken to investigate the long-term results obtained in surgically treated pediatric patients with lumbar disc disease by using standardized medical outcome scales and clinical follow-up examination. METHODS: Twenty nine patients 17 years of age or younger underwent surgery between 1968 and 1998 for lumbar disc disease. The follow-up period ranged from 4 months to 30.5 years (mean 8.5 years). Outcome scores (health profiles) were generated using a standardized medical outcome scale, the Short Form health survey questionnaire (SF-36), and a condition-specific back pain outcome scale. Clinical follow-up data were obtained by telephone interview. The health profile of the study population closely paralleled that of the normal population and was distinctly different from the health profile of adults with low-back pain. Only physical functioning, as measured by a scale of the SF-36, was found to be impaired in a subset of the study population. The rate of reoperation was 24% over the course of the follow-up period. In contrast to similar studies in adults, there were no identifiable predictive factors for either reoperation or poor outcome. CONCLUSIONS: Lumbar disc disease in the pediatric population does not appear to lead to chronic complaints of back pain, and it does not appear to have a negative impact on overall health. This finding suggests that pediatric lumbar disc disease may be a separate entity distinct from adult lumbar disc disease, and therefore, the same conclusions regarding long-term outcome cannot be applied to the pediatric population.

Adolescent↗

Spectrum of occipitoatlantoaxial injury in young children.

OBJECT: Injuries of the occipitoatlantoaxial (Oc-C2) region are the predominant form of cervical injury in children younger than 10 years of age. Magnetic resonance (MR) imaging can be used to visualize directly the traumatic ligamentous and soft-tissue abnormalities of the Oc-C2 region. A retrospective review was undertaken to examine the spectrum of pediatric Oc-C2 injuries seen on MR imaging, their correlation with plain x-ray film and computerized tomography findings, and their clinical course. METHODS: Seventy-one consecutive children younger than 10 years of age underwent cervical MR imaging for evaluation of traumatic injury. Magnetic resonance imaging was used to document abnormalities in 23 children; 20 of these injuries involved the Oc-C2 region. Abnormalities in the Oc-C2 region included disruptions of the musculature, apical ligament, atlantooccipital joint(s), tectorial membrane, and spinal cord. A spectrum of injury with progressive involvement of these structures was seen, ranging from isolated muscular injury to the multiple soft-tissue and ligamentous disruptions with craniocervical dislocation. Involvement of the tectorial membrane was the critical threshold in the transition from stable to unstable injury. Analysis of plain x-ray films revealed that a novel interspinous C1-2:C2-3 ratio criteria of greater than or equal to 2.5 was predictive of tectorial membrane abnormalities on MR imaging, with 87% sensitivity and 100% specificity. In patients with tectorial membrane abnormalities who underwent immobilization alone, interim platybasia was demonstrated on follow-up MR images. Conclusions. A progressive spectrum of distinct Oc-C2 injuries can occur in young children; the tectorial membrane is a critical stabilizing ligamentous structure in the Oc-C2 complex; and tectorial membrane abnormalities may be identified by a C1-2:C2-3 ratio of greater than or equal to 2.5.

Atlanto-Axial Joint↗

Transient hypothermia reduces focal ischemic brain injury in the rat.

The effect of transient hypothermia on focal cerebral ischemia was evaluated using a rat model of permanent middle cerebral artery (MCA) occlusion. MCA occlusion was performed on 10 rats at a temporalis muscle temperature of 24 degrees C (hypothermic group) and on 10 rats at 36 degrees C (normothermic group). Rats in the hypothermic group were maintained at 24 degrees C for 1 hour after MCA occlusion and then allowed to rewarm to 36 degrees C over the next 2 hours. Animals in both groups were killed 24 hours after MCA occlusion. Cerebral infarcts were visualized by staining of coronal brain sections with 2,3,5-triphenyltetrazolium chloride. Normothermic rats displayed an average infarct volume of 233.1 +/- 13.2 mm3 (standard error of the mean), whereas hypothermic rats had an average infarct volume of 166.2 +/- 22.8 mm3 (P less than 0.01). Expressed as a percentage of the volume of the right hemisphere, the normothermic group had an infarct volume of 22.1 +/- 1.5% and the hypothermic group an infarct volume of 16.0 +/- 2.2% (P less than 0.05). These results demonstrate that transient hypothermia to a temporalis muscle temperature of 24 degrees C significantly reduces subsequent infarct size in an experimental model of permanent arterial occlusion.

Animals↗