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We describe a previously healthy 29 year-old man who developed Lhermitte's sign, a shock-like or electric sensation, transmitted down the spine, which occurred during neck flexion or rotation. Evaluation demonstrated an intrinsic, fusiform mass extending from c5 to c7. At operation, the mass was completely removed and found to be a low-grade ependymoma. The sensory phenomena of Lhermitte's sign were most likely caused by tumor-induced distortion and demyelination of cervical dorsal column sensory axons. Lhermitte's sign is most prevalent in patients with multiple sclerosis, cervical spondylotic myelopathy, cisplatin neurotoxicity, cervical radiation injury, and neck trauma. Rarely, Lhermitte's sign occurs with spinal cord compression from epidural or subdural tumor. This patients is the first reported case of an intrinsic spinal cord tumor to present with Lhermitte's sign.

Current epidemiologic evidence indicates that infectious diseases, specifically blood-borne pathogens such as hepatitis B, hepatitis C and HIV, are not transmitted from patient to patient via dental instruments. However, ongoing laboratory investigations suggest that potential pathogens may be retained within dental handpieces, creating a theoretical risk of cross infection. Controversy regarding certain laboratory study results and the clinical implications of these studies continues. Guidelines and regulations for infection control should be rational, and based on a realistic response to a documented risk. Dental professionals should be aware of continuing research focusing on these issues.

Between 1986 and 1990, 37 of 72 patients undergoing decompressive lumbar laminectomy with medial facetectomy for lumbar stenosis at The Ohio State University were seen in follow-up at a mean of 31 months (range, 14-63 months) after their laminectomy and were evaluated by questionnaire, detailed neurologic examination, and static and dynamic lumbar radiographs. Thirteen patients who had undergone fusion or who had extenuating medical circumstances were excluded, leaving 24 patients for whom laminectomy was the sole treatment for lumbar stenosis. Postoperatively, normal walking improved from 4 to 45% of patients, sensory deficits decreased from 63 to 25%, and ability to perform most or all desired activities increased from 25 to 70%. Urinary function was unchanged. Thirteen patients (54%) showed radiographic signs of instability. All patients who were declared radiographically stable could walk without a prosthetic aid or normally; 62% of the unstable patients required aid for walking. All of the patients with a poor ambulatory outcome were radiographically unstable. Compared with stable patients, unstable patients had a significant (p < 0.01) decrease in their ambulatory ability. There was a clear correlation between the degree of listhesis and postoperative ambulatory status (p < 0.01). The unstable patients with a poor ambulatory outcome followed one of three clinical courses: improvement with later deterioration, improvement with a plateau at a poor functional level, or failure to improve from a poor functional level. In conclusion, (a) although instability did not necessarily preclude a good outcome, a poor ambulatory outcome was always associated with instability; (b) laminectomy can effectively ameliorate the symptoms of lumbar stenosis; however, there is a subset of patients in whom laminectomy is associated with instability and a poor clinical course.

Although much has been written regarding treatment of thoracolumbar fractures, questions remain concerning even the most basic issues. This article reviews classification systems, bony stability, the need for neural decompression in thoracolumbar spine fractures, and the literature comparing conservative treatment versus surgical treatment and evaluating various surgical approaches and fixation devices. Finally, data in the available literature and the results of the neurologic examination, radiographic studies, and the magnetic resonance imaging scan are used as the basis for a proposed classification system and a treatment algorithm.

The authors of this article used a laboratory model of herpes simplex virus infection to assess the potential for contamination of dental handpieces by a human viral pathogen. They found that although all the handpieces in the study were fitted with anti-retraction valves, it was not until the units were flushed internally and disinfected externally that the pathogens were eliminated.

A laboratory model of herpes simplex virus infection was used to assess the potential contamination of dental handpieces. When contaminated instruments were treated with surface disinfection and internal chemical disinfection, viable virus was eliminated in all instruments.

We present an unusual patient with a medical history of a fibrosing pseudotumor of the left orbit that had been stable for 8 years who presented with acute anterior hypophyseal failure. During the next 10-month period, sequential magnetic resonance scans showed a rapid growth of a plaque-like sellar and parasellar mass extending into the right cavernous sinus, right Meckel's cave, along the dural surfaces of the clivus, dens, and body of the second cervical vertebra. A transsphenoidal biopsy revealed sphenoid and intrasellar pseudotumor that invaded the adenohypophysis and had microscopic features identical to those of the previously excised orbital pseudotumor. Rapid growth of the pseudotumor continued despite a course of radiotherapy. Palsies of cranial nerves V and VI and of the sensory root of the cranial nerve VII developed on the right side. Steroid therapy was associated with improvement of the cranial nerve palsies. This is the first report of the sellar fibrosing pseudotumor producing not only anterior hypophyseal failure, but also cranial nerve dysfunction secondary to plaque-like extension into the cavernous sinus, Meckel's cave, and cranial base dura. This intracranial plaque-like extension of a fibrous pseudotumor corresponds to a hypertrophic intracranial pachymeningitis, which is a rare, previously described phenomenon associated to the syndrome of multifocal fibrosclerosis.

Panoramic radiographs were completed for patients with leukemia before the start of medical management. The radiographs were taken as part of the patient admission evaluation. Patients were examined and followed throughout the course of their medical management. Panoramic radiographs did not identify pathologic conditions that were not identified clinically or that required management during medical therapy. The radiograph evaluation was of value in correlation with clinical findings and was required before dental treatment. It is concluded that panoramic radiograph evaluation of patients with leukemia is not indicated as part of their routine evaluation and should not be used to screen patients for occult pathosis. The use of these radiographs should be based on history and examination findings.

Dural tears with leakage of cerebral spinal fluid into surrounding soft tissues can occur after traumatic spinal cord injury. An unusual case presented in a patient with traumatic paraplegia where the onset was delayed and clinical features were suggestive of autonomic dysfunction. The clinical features, pathophysiology and treatment of this interesting complication following traumatic spinal cord injury are discussed.

Seven cases of spontaneous epidural abscess are reviewed. Three patients had posterior abscesses and no evidence of vertebral body osteomyelitis. These patients had excellent outcomes with laminectomies and antibiotics. Because of significant vertebral destruction, two patients with vertebral osteomyelitis required posterior fixation after laminectomy. Two other patients with vertebral osteomyelitis had complete destruction of the vertebral body and required anterior decompression and fusion in addition to posterior fixation. In the four patients with vertebral osteomyelitis, morbidity was high, reflecting their age and significant medical problems. This review supports the contention that medically stable patients with posterior epidural abscesses can be treated with laminectomy and antibiotics with little risk of progressive instability. The proper surgical treatment of anterior epidural abscesses secondary to osteomyelitis requires knowledge about the amount of destruction of the supporting columns, the amount of neural compression secondary to the purulence, and the patient's general medical condition.

The effect of basal ganglia stereotactic lesions on motor tone in 3 primates was quantitated. The elastic and neurogenic forces generated with a controlled stretch of each animal's upper extremities were measured pre- and postlesion, and compared to previous studies. The techniques were sensitive to subtle changes in motor tone that were not clinically apparent. The results suggest that the basal ganglia, through the outflow path of the globus pallidus, is important in controlling the sensitivity of both flexors and extensors to stretch. These quantification techniques also have promise in evaluating treatment regimens for spasticity, rigidity, and other conditions with abnormal motor tone.

Ectrodactyly (lobster claw deformity), ectodermal dysplasia and clefting of the lip or palate, the EEC syndrome, is a rare genetic disorder involving both mesodermal and ectodermal derivatives. Cerebral arterial dolichoectasia, a pathological dilatation and elongation of intracranial vessels, was found in a patient with the EEC syndrome. Her hypertensive cardiovascular disease, mild dementia and trigeminal neuralgia were all related to her dolichoectasia. Although the association of dolichoectasia has not been previously observed with the EEC syndrome, it may be more frequent than currently recognized. Cerebral arterial dolichoectasia and its attendant sequelae could account for some of the unexplained abnormalities described in other case reports of patients with the EEC syndrome.

Subependymomas are extremely rare tumors in the pediatric population and, when they occur, they are usually of a mixed type with elements of subependymoma and ependymoma. This report is of a 2 1/2-year-old male infant with a pure subependymoma of the fourth ventricle.

Serum levels of creatine kinase (CK) and its myocardial isoenzyme (CK-MB) were measured and serial ECG recorded in 24 male and 6 female patients with severe head trauma. All patients were comatose, but no patient sustained a spinal or chest injury. Total CK activity was elevated in at least one sample in each patient. Elevated CK-MB activity was found in 28 patients. The serial CK-MB data did not follow the same pattern as that of patients suffering from myocardial infarctions. The mean CK-MB remained elevated for at least 3 days after injury, although individual patterns were variable. ECG abnormalities included prolonged corrected QT interval (QTc) in 90% and a variety of nonspecific ST segment and T wave changes in 53%. These ECG findings are consistent with other clinical studies of severe neurological disorders, particularly cerebrovascular accidents. The elevated CK-MB activity indicates that ongoing myocardial damage occurs in patients with severe head injury. Although the underlying mechanism is not entirely clear, an excessive release of catecholamines is the most likely mechanism accounting for diffuse myocardial damage, prolonged elevated CK-MB values and the observed ECG abnormalities.

The kinematics of a visually guided, multi-joint arm movement were examined before and after combined bilateral premotor and supplementary motor cortex lesions. Two rhesus monkeys were trained to move a manipulandum from a start zone to one of three equally spaced target zones and then return to the initial start zone. Various features of the movement trajectory including space error, time error, peak velocity and turnaround time were quantified and analyzed before and after the premotor and supplementary motor cortex ablations. Statistical analysis showed no major differences in the trajectories toward or away from the target between the pre- and postlesion state. The major difference following the ablation was an increase in the time spent in the target zone, reflecting an increase in time spent in redirecting the trajectory. Normalization of the movement duration revealed a slight delay in the initial part of the movement. These results suggest the premotor and supplementary motor cortex are involved in redirecting the trajectory and/or obtaining the target zone during the execution of a complex movement.

Comparison was made of the effectiveness of cerebellar cortical and nuclear stimulation in reducing paroxysmal activity induced in cats by parenteral penicillin administration. Vermal cortical and fastigial nuclear stimulation at high frequencies (100 Hz) were both effective in reducing the number and duration of paroxysmal events while the effects of dentate nucleus stimulation were found to be more variable. It was suggested that effective seizure inhibition appeared to be associated with increased fastigial output and resultant reticular excitation.

This study deals with the use of microcomputer graphic analysis of preoperative magnetic resonance imaging (MRI) scans in functional neurosurgical procedures. Three patients (2 treated for thalamotomy and 1 for thalamic stimulation) had preadmission MRI scans which delineated the classic internal landmarks used in functional neurosurgery. These data were then manipulated and stored using a microcomputer-based graphic analysis system. Intraoperative pattern matching of preadmission graphics with the intraoperative skull X-rays allowed determination of the planned target in the x, y and z coordinates. The accuracy of the graphics FM-PC and AC-PC points was confirmed with the use of ventriculography, stimulation, and postoperative MRI scans. This simple, inexpensive method obviates the need for ventriculography, sedation, intraoperative MRI with a scan-compatible frame, and has the accuracy necessary for functional procedures.

Osteonecrosis is a severe complication of radiotherapy for cancer. Prevention of osteonecrosis is most important, as the condition may be chronic, progressive, and lead to pathologic fracture. The clinical experience, of 627 dental extractions at the Cancer Control Agency of British Columbia either before or after radiotherapy is presented.

The literature regarding the intrathecal use of morphine, baclofen, and midazolam to treat spasticity is reviewed. Nine patients with significant spasticity due to different etiologies were treated. Morphine and midazolam decreased spasticity but did not change the patient's functional status. Baclofen improved patient status, but was associated with significant CNS depression in two cases.