Karl A. Greene

Acute axis fractures. Analysis of management and outcome in 340 consecutive cases.

Study Design. Retrospective review of acute axis fractures treated at a tertiary referral center. Objective. To determine the optimal treatment of axis fractures based on 340 cases from a single institution. Summary of Background Data. Axis fractures account for almost 20% of acute cervical spine fractures. However, their management and the clinical criteria predictive of nonoperative failure remain unclear. Methods. Admission imaging studies and clinical variables were obtained for 340 consecutive axis fracture patients. Fractures were classified as odontoid Type I, II, or III with dens displacement on admission roentgenograms; hangmans fractures of Francis grade and Effendi type; and miscellaneous fractures. Treatment methods were documented, and outcomes were based on dynamic lateral roentgenograms, clinical examination, or telephone interviews at last follow‐up. Results. Follow‐up data were available in 92% of cases. Type II odontoid fractures comprised 35% of all axis fractures, were the most difficult to treat, and had the highest nonunion rate (28.4%). Odontoid displacement of 6 mm or more was associated with Type II nonunion (chi‐square = 33.74, P < 0.0001). Patients underwent surgical fusion if fracture alignment could not be maintained by an external orthosis, or if they had odontoid fractures with transverse ligament disruption, Type II odontoid fractures with dens displacement of at least 6 mm, or hangmans fractures of severe Francis grade or Effendi type. Conclusions. Type II odontoid fractures have the highest nonunion rate and were associated with dens displacement of 6 mm or greater. Early surgical fusion is recommended for acute fracture instability despite external immobilization, transverse ligament disruption, Type II odontoid fractures with dens displacement of at least 6 mm on admission, or severe Francis grade or Effendi‐type hangmans fractures. Otherwise, nonoperative management is sufficient.

Transverse atlantal ligament disruption associated with odontoid fractures.

Objectives. The authors evaluated transverse atlantal ligament integrity in patients with fractures of the odontoid process of the axis. Summary of Background Data. Injuries of the transverse atlantal ligament can result in atlantoaxial instability after fractures of the atlas or axis, even if osseous healing occurs. Methods. The clinical histories and follow‐up examinations and radiographic data of 30 patients with odontoid fractures were reviewed, using a combination of magnetic resonance (MR) imaging, thin‐cut computed tomography (CT), and plain radiographs to evaluate osseous and ligamentous injuries. Results and Conclusions. Osteoperiosteal ligamentous avulsion injuries were identified on MR imaging in three patients and were associated with acute and delayed instability and nonunion. The combination of MR imaging, CT, and plain radiographs is useful in evaluating unstable odontoid fractures to facilitate rational treatment planning. Odontoid fractures with transverse ligament injuries should be considered for early surgical stabilization because this combination of injuries is unlikely to heal nonoperatively. Anterior odontoid screw fixation should be avoided when the ligament is injured. [Key words: cervical spine injury, magnetic resonance imaging, odontoid fracture, transverse atlantal ligament] Spine 1994;19:2307‐2314

Impact of traumatic subarachnoid hemorrhage on outcome in nonpenetrating head injury. Part II: Relationship to clinical course and outcome variables during acute hospitalization.

Patients with a nonpenetrating head injury and traumatic subarachnoid hemorrhage (tSAH) on admission head computed tomography scan (n = 240) were compared with patients without tSAH matched in terms of admission postresuscitation Glasgow Coma Scale (GCS) values, age, sex, and the presence of one or more types of intracranial mass lesions. Admission Injury Severity Score was higher only in tSAH patients with admission GCS scores between 13 and 15; GCS values at 6, 24, and 48 hours were lower for tSAH patients. Patients with tSAH underwent fewer craniotomies, but more than twice as many tSAH patients had high intracranial pressure at the time of ventriculostomy placement and 6 hours after admission. tSAH patients underwent more chest procedures and their incidence of hypoxia and hypotension was greater. tSAH patients spent more days in intensive care unit, more total days hospitalized, and had worse Glasgow Outcome Scale scores at acute hospital discharge. Fewer tSAH patients were discharged home, and almost 1.5 times as many tSAH patients died during hospitalization. Given a similar overall degree of injury at admission, patients with tSAH associated with a nonpenetrating head injury had a worse outcome than similar patients without tSAH.

Physiology and pathophysiology of cortico-basal ganglia-thalamocortical loops: theoretical and practical aspects.

A new theoretical framework is used to analyze functions and pathophysiological processes of cortico-basal ganglia-thalamocortical loops and to demonstrate the hierarchical relationships between various loops. All hierarchical levels are built according to the same functional principle: Each loop is a neural optimal control system (NOCS) and includes a model of object behavior and an error distribution system. The latter includes dopaminergic neurons and is necessary to tune the model to a controlled object (CO). The regularities of pathophysiological processes in NOCSs are analyzed. Mechanisms of current functional neurosurgical procedures like lesioning and deep brain stimulation (DBS) of various basal ganglia structures and neurotransplantation are described based on proposed theoretical ideas. Parkinsons disease (PD) is used to exemplify clinical applications of the proposed theory. Within the proposed theoretical framework, PD must be considered as a disease of the error distribution system. The proposed theoretical views have broad fundamental and clinical applications.

Cardiopulmonary Bypass, Hypothermic Circulatory Arrest and Barbiturate Cerebral Protection for the Treatment of Giant Vertebrobasilar Aneurysms in Children

Intracranial aneurysms in the pediatric population are rare lesions with a significant proportion occurring as giant aneurysms involving the vertebrobasilar system. The complex anatomy of these lesions frequently creates an extremely difficult management dilemma. We present two patients, a 9-year-old and a 13-year-old, with giant fusiform vertebrobasilar aneurysms, to illustrate the utility of cardiopulmonary bypass, hypothermic circulatory arrest and barbiturate cerebral protection for successful surgical treatment of these complex intracranial vascular lesions in children.

Pharmacological management of spinal cord injury : Current status of drugs designed to augment functional recovery of the injured human spinal cord

Spinal cord injury often results in devastating physical, psychological, and economic disabilities. Research efforts are directed toward providing prognostic outcome data and animal models that parallel the human disorder, thereby elucidating the mechanisms responsible for its dismal clinical prognosis. Investigators continue to search for pharmacological agents that halt the cascade of events that lead to loss of function after cord injury. The scientific and federal regulatory processes by which new drugs are discovered and implemented clinically permit clinicians to evaluate the potential benefits of any new agent, and provide an estimate of the duration required for promising new agents to be made clinically available. Understanding these processes makes the task of classifying the availability status of new drugs much simpler, allowing rational dissemination of realistic information to patients and their families frequently made desperate for viable alternatives to the prospect of permanent paralysis. In this review, we describe the scientific and regulatory processes necessary for the clinical introduction of new drugs using spinal cord injury as an example. A classification scheme based on current Food and Drug Administration regulations is presented that provides drug availability status at a glance. It is hoped that such an organizational scheme will be of practical benefit to clinicians involved in the management of spinal cord-injured patients.

Mouse brain concentrations of 3-methoxytyramine and normetanephrine: a comparison of methods of sacrifice.

The identification of sacrifice methods that produce reliable measures of baseline central nervous system neurotransmitter concentrations poses a challenge to analytical neurochemical investigation. In the present study, microwave irradiation (MWVI) was compared with in situ freezing, cervical dislocation, and simple decapitation, in an effort to examine their effects on whole mouse brain concentrations of 3-methoxytyramine (3MT) and normetanephrine (NMN), the O-methylated catecholamine metabolites believed to be sensitive indicators of release of CNS dopamine and norepinephrine, respectively. Both high-energy (6 kW, 0.3 s) and low-energy (2.5 kW, 1.5 s) MWVI produced the lowest mouse brain concentrations of 3MT and NMN when compared with other methods of sacrifice within experiments. In situ freezing resulted in values of 3MT and NMN that were slightly, yet significantly, higher than MWVI within experiments. The concentrations of 3MT and NMN obtained following either cervicle dislocation or simple decapitation were up to 9-fold greater than those produced by either of the two previous methods.

Relationship Between Plasma and Cerebrospinal Fluid Norepinephrine and Dopamine Metabolites in a Nonhuman Primate

Abstract: Major and minor pathways of metabolism in the mammalian CNS result in the formation of 3‐methoxy‐4‐hydroxyphenylethylene glycol (MHPG) and normetane‐phrine (NMN) from norepinephrine (NE), and homovanillic acid (HVA) and 3‐methoxytyramine (3‐MT) from dopamine (DA), respectively. The correlational relationships between HVA and 3‐MT and between MHPG and NMN in primate CSF and plasma have not been described. These relationships may help to elucidate the usefulness of CSF and plasma metabolites as indices of CNS NE and DA activity. In addition, because NMN is unlikely to cross the blood‐brain barrier, CSF NMN concentrations would not be confounded by contributions from plasma, which is a major issue with CSF MHPG. We have obtained repeated samples of plasma and CSF from drug‐naive male squirrel monkeys and have measured the concentrations of MHPG, HVA, NMN, and 3‐MT to define their correlational relationships. For the NE me‐tabolites, significant correlations were obtained for CSF MHPG and NMN (r = 0.806, p < 0.001), plasma MHPG and CSF NMN (r= 0.753, p < 0.001), and plasma and CSF MHPG (r= 0.776, p< 0.001). These results suggest that CSF and plasma MHPG and CSF NMN may reflect gross changes in whole brain steady‐state noradrenergic metabolism. Only a single significant relationship was demonstrated for the DA metabolites, with CSF 3‐MT correlating with plasma HVA (r= 0.301, p < 0.025). The results for the DA metabolites probably reflect regional differences in steady‐state brain dopaminergic metabolism.

Glossopharyngeal neuralgia associated with vascular compression and choroid plexus papilloma

We report two cases of presumed idiopathic glossopharyngeal neuralgia that were discovered intraoperatively to be associated with compression by choroid plexus papillomas, and by a variable degree of vascular compression at the root entry zones of cranial nerves IX and X. The combination of the two entities in glossopharyngeal neuralgia has not previously been reported.

The effect of chronic alprazolam on sleep and bioamine metabolites in depression

Alprazolam administered for 43 days in doses of 6 to 10 mg/day had an antidepressant effect in four of nine depressed patients. Decreases in slow wave sleep, increases in rapid eye movement (REM) latency, and decreases in REM minutes and percent and REM sleep eye movements were found in the group as a whole. The drug had a general hypnotic effect with a trend toward increased total sleep time. Nonsignificant changes in the concentrations of 3-methyl-4-hydroxyphenylglycol and homovanillic acid in the cerebrospinal fluid (CSF) were qualitatively similar to those found after treatment with tricyclic antidepressant drugs; however, only the larger decreases in CSF 5-hydroxyindoleacetic acid achieved statistical significance. Baseline sleep and CSF metabolites and changes in these measures on drug did not predict the therapeutic effects of alprazolam.