Neurosurg Focus
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Comparative Study Clinical Trial
Efficacy of anterior odontoid screw fixation in elderly patients with Type II odontoid fractures.
Type II odontoid fractures are the most common trauma-related dens fracture. Although Type III odontoid fractures have a high union rate when external immobilization is applied, Type II fractures are associated with high rates of nonunion, particularly in elderly patients and those with posteriorly displaced fractures or fractures displaced by more than 6 mm. Because elderly patients may not also tolerate external immobilization in a halo vest, alternative techniques should be explored to identify a method for managing these higher-risk patients. In this study the authors examine the efficacy of anterior odontoid screw fixation in a high-risk group of 10 elderly patients (> 65 years of age) treated for Type II odontoid fractures. ⋯ Odontoid screw fixation can be safely performed in elderly patients, and frequent bone union is demonstrated. However, osteopenia may preclude adequate screw fixation in some patients.
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Disturbed ionic and neurotransmitter homeostasis are now recognized to be probably the most important mechanisms contributing to the development of secondary brain swelling after traumatic brian injury (TBI). Evidence obtained from animal models indicates that posttraumatic neuronal excitation via excitatory amino acids leads to an increase in extracellular potassium, probably due to ion channel activation. The purpose of this study was therefore to measure dialysate potassium in severely head injured patients and to correlate these results with intracranial pressure (ICP), outcome, and also with the levels of dialysate glutamate, lactate, and cerebral blood flow (CBF) so as to determine the role of ischemia in this posttraumatic ionic dysfunction. ⋯ The simultaneous increase of potassium, together with dialysate glutamate and lactate, supports the hypothesis that glutamate induces ionic flux and consequently increases ICP due to astrocytic swelling. Reduced CBF was also significantly correlated with increased levels of dialysate potassium. This may be due to either cell swelling or altered potassium reactivity in cerebral blood vessels after trauma.
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The author describes a technique of thoracic discectomy that has evolved from the posterolateral transfacet and the transpedicular approaches but that spares the pedicle and most of the facet joint. ⋯ This technique appears safe and effective. It can be adapted to the conventional laminectomy known to spine surgeons and requires no specialized instruments. Further trials appear warranted.
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Comparative Study Clinical Trial
Changes in cerebral blood flow and oxygen metabolism during moderate hypothermia in patients with severe middle cerebral artery infarction.
Moderate hypothermia has been reported to be effective in the treatment of postischemic brain edema. The effect of hypothermia on cerebral hemodynamics is a matter of controversial discussion in literature. Clinical studies have yet to be performed in patients with ischemic stroke after induction of hypothermia. ⋯ Preliminary oberservations indicate that moderate hypothermia seems to reduce CMRO2. Immediately after induction of hypothermia, CBF may decrease in all patients. During late hypothermia CBF seems to recover in patients with good outcome but remains diminished in patients who die. Serial bedside CBF measurements with the new double-indicator dilution technique may be useful to describe cerebral hemodynamic characteristics in patients with severe ischemic stroke during hypothermia.
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In an attempt to assess admission Glasgow Coma Scale (GCS) scores and other radiographic variables after penetrating craniocerebral injury in relationship to outcome, the author evaluated a series of 294 patients with penetrating injuries who presented with a GCS score of 6 to 15 over a 6-year period. Entrance criteria required a replicable neurological examination that was not altered by the presence of hypotension, drugs/toxins, or systemic injury. All patients underwent surgical intervention and aggressive perioperative management, including resuscitative protocols, in the neurosurgical intensive care unit. ⋯ No significant relationships between operative intervention and survival were found in patients with admission GCS scores of 9 to 12 and 13 to 15. A significant relationship between operative intervention and morbidity (p < or = 0.01) was also demonstrated in patients with an admission GCS score of 12 to 15. No significant relationships between operative intervention and morbidity were found in patients with an admission GCS score of 6 to 8 and 9 to 12.