Os odontoideum is a common cause of atlantoaxial instability in the pediatric population. The authors present the cases of 2 patients whose initial clinical presentation and MR imaging findings were suggestive of an intramedullary neoplasm, but whose ultimate diagnosis was determined to be cervical spine instability and cord injury due to os odontoideum.
Paul R. Gigante, Neil A. Feldstein and Richard C. E. Anderson
Abstract (Jea et al.)
The authors describe the novel use of C-1 lateral mass screws in four children 8 years of age or younger, in whom occipitocervical or atlantoaxial fusion was performed for trauma or os odontoideum. The authors retrospectively reviewed the demographics and procedural data of four children, ranging in age from 2 to 8 years, who required and underwent surgical fixation. Although C1–2 screw/rod constructs involving individual C-1 lateral mass screws and C-2 pars interarticularis or pedicle screws have been widely applied in adults, only C1–2 transarticular screw fixation has been reported in children less than 8 years of age. This report demonstrates the successful results of rigid occipitocervical and atlantoaxial fusion in four children in whom C-1 lateral mass screws were placed as part of a screw/rod construct. There was one instance of a vertebral artery injury, and the lessons learned from this complication are discussed.
Richard H. Moiel, George Ehni and M. Sidney Anderson
Part 3: The Effect of Increased Intracranial Pressure on the Cardiovascular Hemodynamics of Chimpanzees
Thomas B. Ducker, Richard L. Simmons and Robert W. Anderson
Report of two cases and review of the literature
Ganesh Rao, Richard C. E. Anderson, Neil A. Feldstein and Douglas L. Brockmeyer
✓Arachnoid cysts are intracranial, space-occupying lesions that typically remain stable in size on serial imaging. The authors describe two cases of rapidly enlarging arachnoid cysts, including one located in the anterior fossa.
In the first case a 7-month-old boy presented with increasing head circumference and a rapidly enlarging arachnoid cyst in the left middle fossa, which had been documented by serial imaging over the preceding 6 months. In the second case a 4-year-old girl presented with an arachnoid cyst compressing the right frontal lobe. The cyst had not been present on imaging studies performed during the perinatal period. In both cases, a craniotomy for open fenestration of the cyst was performed with successful resolution of the mass effect.
Rare cases of expansion of arachnoid cysts have been reported in the literature. In this article the authors report the dramatic enlargement of two arachnoid cysts, including the first description of enlargement of an arachnoid cyst located in the anterior fossa.
Richard C. E. Anderson, Peter Kan, Kris W. Hansen and Douglas L. Brockmeyer
Currently, no diagnostic or procedural standards exist for clearing the cervical spine in children after trauma. The purpose of this study was to determine if reeducation of nonneurosurgical personnel and initiation of a new protocol based on the National Emergency X-Radiography Utilization Study criteria could safely increase the number of pediatric cervical spines cleared of suspected injury without a neurosurgical consultation.
Data regarding cervical spine clearance in children (ages 0–18 years) after trauma protocol activation at Primary Children's Medical Center between 2001 and 2005 were collected and reviewed. Radiographic and clinical methods of clearing the cervical spine as well as the type and management of injuries were determined for two time frames: Period I (January 2001–December 2003) and Period II (January 2004–July 2005).
Between 2001 and 2003, 95% of 936 cervical spines were cleared of suspected injury by the neurosurgical service. Twenty-one ligamentous injuries (2.2%) and 12 fracture–dislocations (1.3%) were detected, with five patients requiring surgical stabilization (0.5%). Between January 2004 and July 2005, 507 (68%) of 746 cervical spines were cleared by nonneurosurgical personnel. Six ligamentous injuries (0.8%) and 10 fracture–dislocations (1.3%) were identified, with three patients (0.4%) requiring surgical stabilization. No late injuries were detected in either period.
The protocol used has been effective in enabling detection of cervical spine injuries in children after trauma, with the new protocol increasing by more than 60% the number of cervical spines cleared by nonneurosurgical personnel. Reeducation with establishment of the new protocols can safely facilitate clearance of the cervical spine by nonneurosurgical personnel after trauma.
Hannah E. Goldstein, Neil A. Feldstein and Richard C. E. Anderson
W. Richard Marsh, Robert E. Anderson and Thoralf M. Sundt Jr.
✓ The adverse effect of a minimal cerebral blood flow (CBF) in models of global ischemia has been noted by many investigators. One factor believed important in this situation is the level of blood glucose, since a continued supply of this metabolite results in increased tissue lactate, decreased brain pH, and increased cell damage. The authors have extended these observations to a model of focal incomplete ischemia. Brain pH was measured in fasted squirrel monkeys in regions of focal incomplete ischemia after transorbital occlusion of the middle cerebral artery (MCA). In both control and hyperglycemic animals, CBF was reduced to less than 30% of baseline. At 3 hours after MCA occlusion, brain pH in the control group was 6.66 ± 0.68 as compared to 6.27 ± 0.26 in the glucose-treated group. This difference was statistically significant by Student's unpaired t-test (p < 0.05). Thus, hyperglycemia results in decreased tissue pH in regions of focal incomplete cerebral ischemia in monkeys.
Lloyd S. Anderson, Richard G. Black, Jacob Abraham and Arthur A. Ward Jr.
✓ Postoperative facial paresthesias frequently occur in patients following retrogasserian rhizotomy. To investigate the etiology of these paresthesias, microelectrode recordings of neuronal activity were made from the brain stem of the cat at variable times after trigeminal root section. Spontaneous neuronal hyperactivity was recorded from the deafferented spinal trigeminal nucleus in animals studied 8 to 10 days following rhizotomy. After this time the hyperactivity was found to progressively increase and was greatest in animals 1 month after rhizotomy, which was the longest time interval between rhizotomy and microelectrode recordings studied. The neuronal hyperactivity was similar to single cell recordings from cerebral epileptic foci both in monkey and man. This supports earlier experimental information that neuronal deafferentation is a factor in the development of epileptic activity. The authors postulate that brain-stem neuronal hyperactivity similar to epileptic activity is the physiological correlate of paresthesias that occur after sectioning the root of the trigeminal nerve. Further, if retrogasserian rhizotomy causes neuronal seizure activity in the spinal trigeminal nucleus, it may also be possible for trigeminal deafferentation produced by certain pathological processes involving the trigeminal nerve or ganglion to be the basis for other sensory disorders involving the face, i.e., trigeminal neuralgia.