Faculty Bibliography

Concussion has a long and interesting history spanning at least the 5 millennia of written medical record and closely mirrors the development of surgery and neurosurgery. Not surprisingly, much of the past and present experimental head injury and concussion work has been performed within neurosurgically driven laboratories or by several surgically oriented neurologists. This historical review chronicles the key aspects of neurosurgical involvement in sports concussion as related to the diagnosis, treatment, mitigation, and prevention of injury using the example of American football. In addition, we briefly trace the developments that led to our current understanding of the biomechanical and neurophysiological basis of concussion.

OBJECT: Halo orthosis placement is a common neurosurgical procedure for the treatment of cervical spine injuries. Frontal sinus puncture by the anterior pins may occur using standard techniques, and up to 30% are dissatisfied with forehead scarring, especially women and African Americans. METHODS: The authors describe a frontolateral (FL) anterior pin site placement supported by high-resolution CT scan skull thickness measurements. The standard supraorbital (SO) pin site is several centimeters above the lateral orbit, whereas the FL pin site is 2-3 cm posterolateral to the SO site. Frontolateral placement is just anterior to the temporalis muscle close to a triangular anterior projection of the temporal hairline. For quantitative information on skull thickness at the SO and FT pin sites, thin 0.625-mm CT scan measurements of the outer table, diploic space, and inner table were obtained in 40 adults (80 sites). RESULTS: The mean values for total skull thickness at the SO and FT sites were not significantly different. The inner table was significantly thicker at the FL site in both males and females, buttressed by the nearby greater sphenoid wing. The mean total skull thickness was significantly less in females than in males, but the values were not significantly different at the SO and FL sites. CONCLUSIONS: The FL and SO anterior pin sites are comparable with respect to skull thickness CT measurements, with a significantly thicker inner table at the FL site. In the senior author's experience, the FL anterior pin site yielded secure fixation without skull perforation, neurovascular injury, or propensity to infection. The cosmetic result of the FL site is more acceptable, and the authors recommend its general usage be adopted.

The field of electroencephalography (EEG) had its origin with the discovery of recordable electrical potentials from activated nerves and muscles of animals and in the last quarter of the 19th century from the cerebral cortex of animals. By the 1920s, Hans Berger, a neuropsychiatrist from Germany, recorded potentials from the scalp of patients with skull defects and, a few years later, with more sensitive equipment from intact subjects. Concurrently, the introduction of electronic vacuum tube amplification and the cathode ray oscilloscope was made by American physiologists or "axonologists," interested in peripheral nerve recordings. Berger's findings were independently confirmed in early 1934 by Lord Adrian in England and by Hallowell Davis at Harvard, in the United States. In the United States, the earliest contributions to human EEG were made by Hallowell Davis, Herbert H. Jasper, Frederic A. Gibbs, William Lennox, and Alfred L. Loomis. Remarkable progress in the development of EEG as a useful clinical tool followed the 1935 report by the Harvard group on the electrographic and clinical correlations in patients with absence (petit mal) seizures and altered states of consciousness. Technical aspects of the EEG and additional clinical EEG correlations were elucidated by the above investigators and a number of others. Further study led to gatherings of the EEG pioneers at Loomis' laboratory in New York (1935-1939), Regional EEG society formation, and the American Clinical Neurophysiology Society in 1946.

The authors report their experience utilizing a recently described rapid rate, binaural click and 1000-Hz tone burst modification of the brain stem auditory evoked potentials (BAEP), modified (MBP), in 27 symptomatic patients with non-brain stem compressive space-taking cerebral lesions (22), hydrocephalus (4), and pseudotumor cerebri (1). Many presented with clinical signs suggestive of increased intracranial pressure (ICP) and focal neurological deficits. The cerebral lesions, mostly large tumors with edema, had very substantial radiological signs of mass effect. Fourteen patients were also studied following surgical decompression. A number of significant changes in the wave V and Vn latency/intensity and less so amplitude/intensity function was found in the 27 patients, compared to normal volunteers, as well as those studied pre- and postoperatively. Similar MBP changes had been noted in normal volunteers placed in a dependent head position. Possible mechanisms to explain these findings are discussed. The MBP methodology shows promise and further development could make neuro-intensive care unit monitoring practical.

Frederic Gibbs' (1903-1992) long research career was devoted to the understanding and treatment of epileptic phenomena and closely associated with the development of electroencephalography (EEG). After medical school, he joined the Harvard Neurological Unit at Boston City Hospital directed by Stanley Cobb. In the early 1930s, Gibbs developed a thermoelectric blood flow probe and, with William Lennox, proved in animals and humans that a seizure increases cerebral blood flow. By 1934, Gibbs became a pioneer in the field of EEG while working at Harvard with Hallowell Davis and Lennox, and was the first to convincingly record and report EEG findings in epilepsy and states of altered consciousness. Several years later, Gibbs and Lennox were the first to recommend cerebral excisions in several patients with uncontrolled epilepsy based on EEG. Moving to the University of Illinois at Chicago in 1944, Gibbs founded a consultation clinic for epilepsy, performed the first EEG depth recordings using pneumoencephalography-guided stereotaxy, and noted that sleep EEGs in patients with psychomotor seizures frequently disclosed temporal epileptic patterns. Gibbs convinced Percival Bailey to collaborate on patients with refractory temporal lobe psychomotor seizures without tumors. In 1947, the first nonlesional temporal lobe excisions based on EEG localization were performed in these patients, and, by 1948, anterior temporal lobectomy had become their procedure of choice. Gibbs and Lennox received the coveted Lasker Award among other honors as pioneers in establishing the modern era of epilepsy diagnosis and treatment.

The brainstem auditory evoked response (BAER) is sensitive to pontomesencephalic integrity, transtentorial brain herniation, and at times increased intracranial pressure (ICP). The authors report their experience utilizing a recently described rapid rate, binaural, click and 1,000-Hz tone-burst modification of the BAER (MBAER) in 22 symptomatic non-trauma patients with non-brainstem compressive space-taking cerebral lesions. The majority presented with mild to moderate clinical signs suggestive of increased ICP, and focal neurological deficits. The cerebral lesions, mostly tumors (17), averaged 4-5 cm in diameter, with radiological signs of mass effect such as flattening of the sulci, midline shift, and narrowing of the basal cisterns. A number of significant changes in Wave V and V (n) latency and less so amplitude were found in patients compared with age-matched normal volunteers, as well as those again studied after surgical decompression. Similar MBAER changes had been noted in normal volunteers placed in a dependent head position. Possible mechanisms to explain these findings are discussed. The methodology shows promise and if combined with automated peak recognition could make Neuro ICU monitoring practical.

Psychomotor seizures, referred to as limbic or partial complex seizures, have had an interesting evolution in diagnosis and treatment. Hughlings Jackson was the first to clearly relate the clinical syndrome and likely etiology to lesions in the uncinate region of the medial temporal lobe. With the application of electroencephalography (EEG) to the study of human epilepsy as early as 1934 by Gibbs, Lennox, and Davis in Boston, electrical recordings have significantly advanced the study of epilepsy. In 1937, Gibbs and Lennox proposed the term "psychomotor epilepsy" to describe a characteristic EEG pattern of seizures accompanied by mental, emotional, motor, and autonomic phenomena. Concurrently, typical psychomotor auras and dreamy states were produced by electrical stimulation of medial temporal structures during epilepsy surgery by Penfield in Montreal. In 1937, Jasper joined Penfield, EEG was introduced and negative surgical explorations became less frequent. Nevertheless, Penfield preferred to operate only on space occupying lesions. A milestone in psychomotor seizure diagnosis was in the year 1946 when Gibbs, at the Illinois Neuropsychiatric Institute, Chicago, reported that the patient falling asleep during EEG was a major activator of the psychomotor discharges and electrographic ictal episodes becoming more prominently recorded. Working with Percival Bailey, Gibbs was proactive in applying EEG to define surgical excision of the focus in patients with intractable psychomotor seizures. By early 1950s, the Montreal group began to clearly delineate causative medial temporal lesions such as hippocampal sclerosis and tumors in the production of psychomotor seizures.