[Short-latency, brainstem, trigeminal evoked-potentials]

Short-latency, evoked-potentials were recorded from over the scalp in response to electrical stimulation of the upper lip, using the Microshev 4000 equipment (Microshev Co., Efrat). Normative data were obtained from 35 normal volunteers. The brain-stem, trigeminal evoked-potentials (BTEP) consisted of 4 distinct, well-reproduced waves evoked in less than 10 msec. The waves, named after their respective latencies, are thought to be generated in the preganglionic trigeminal nerve (T1), the postganglionic nerve entry zone (T2), in the trigeminal nucleus (T3) and the upper brainstem (T5). BTEP was recorded in nearly 200 patients suffering from various lesions in the peripheral trigeminal parts, tumors affecting the brainstem (before, during and after surgery) and in varying degrees of post-traumatic coma. BTEP proved to be a reliable tool for evaluating the brainstem trigeminal system; changes in its pattern reliably reflected altered activity of that system. It can be used for diagnosis as well as for intraoperative monitoring of brainstem function.

Head injuries in the elderly

Two hundred and sixty-three consecutive head-injured patients aged over 65 years, admitted to a neurosurgical service, are reported. In contrast to younger age group the main cause was falls concomitant with a high rate of cardiovascular pre-existing disorders. The distribution of causes and grim results justify, in our opinion, regarding head injury in the elderly as a distinct entity requiring special surgical, medical, organizational and ethical considerations.

[Visual hemineglect as presenting symptom of right parietal tumors]

4 patients with malignant right parietal brain tumors (2 with gliomas and 2 with metastases) presented with difficulties in driving due to visual hemineglect, thought at first to be due to absent-mindedness or forgetfulness. Visual neglect is one aspect of the syndrome of unilateral neglect, which is a selective disturbance in the internal representation of the body image and processing of information from the extrapersonal space. The cerebral mechanisms underlying the phenomenon are reviewed.

A physiological coma scale: grading of coma by combined use of brain-stem trigeminal and auditory evoked potentials and the Glasgow Coma Scale

Forty-five comatose patients were prospectively studied by means of clinical examination and evoked potentials. In each patient, clinical data included Glasgow Coma Scale (GCS) score, age, pupillary response to light, corneal reflex, and eye movements. Neurophysiological evaluation was based on brain-stem trigeminal evoked potentials (BTEPs) and brain-stem auditory evoked potentials (BAEPs). For each physiological test, a progressive grading system was designed. This system was based on the evaluation of central conduction times along the trigeminal and the auditory pathways within the brain-stem. The accuracy of the clinical and the neurophysiological indicants in predicting "favorable" or "unfavorable" outcome was assessed singly and in combination. Of the clinical indicants, the GCS provided the most accurate prognosis (80%). Similar results were provided by the BAEP and the BTEP, with significant improvement in the confidence of outcome prediction. No significant difference in the accuracy of outcome predictions could be found between combined clinical data and neurophysiological data. However, the combination of clinical and neurophysiological data markedly increased both the accuracy and the confidence of outcome prediction, reaching 86% correct predictions at the over 90% confidence level with only 2% false pessimistic errors. According to these findings, a clinical-physiological coma scale, the trigeminal-auditory Glasgow (Coma Scale) score (TAG score) was designed. The TAG score demonstrated the highest accuracy at each confidence level as compared to other single indicants. We concluded that the TAG score may improve the evaluation of deep comatose patients and assist the physician in the management of such patients.

Monitoring of brain-stem trigeminal evoked potentials. Clinical applications in posterior fossa surgery

Brain-stem trigeminal evoked potentials (BTEPs) were monitored intraoperatively in 17 patients during posterior fossa surgery. Satisfactory BTEP recording was performed in all patients without technical problems or interfering with the activity of the operating team. The BTEP was not altered by anesthetic agents or muscle relaxants. Intraoperative monitoring of the BTEP showed wave form alterations or increasing peak latencies in 10 patients. Among these patients, the BTEP demonstrated a dynamic correlation with the surgical process in 8 instances. Two major causative surgical manipulations were identified: cerebellar retraction in 4 cases and tumor dissection from the brain-stem in 6 cases. Withholding the dissection of the tumor, readjusting a cerebellar retractor or further modifying the surgical attitude resulted in partial or complete return of the wave form in 7 patients. The BTEP at the end of surgery proved to correlate with the immediate surgical outcome in most instances. We concluded that the intraoperative monitoring of the BTEP was feasible and suggested, despite the small number of patients, a potential value in the survey of brain-stem functions during posterior fossa surgery.

Density spectral array, evoked potentials, and temperature rhythms in the evaluation and prognosis of the comatose patient

Glasgow Coma Scale (GCS), density spectral array (DSA), EEG, BAEP and circadian temperature rhythm were studied in comatose patients in order to determine level of arousal and appraise the prognostic capability of these combined measures. Subjects were 29 comatose patients in the neurosurgical ICU at the Rambam Medical Center suffering from head trauma, vascular disorders or metastatic growth. Results show that best prognostic capabilities were for DSA, GCS and BAEP, in that order. As a single parameter physiological response to a sound stimulus (increase in EMG, change in EEG frequency and appearance of sharp waves or k-complex) was the single best predictor for outcome, with significant response rates for the good, deficit, vegetative and death outcomes at 83%, 57%, 37% and 18%, respectively. Rectal temperature was analysed for 24 h circadian periodicity. Daily acrophases were found to shift forward or backward on the level of about 2-7 h a day with fluctuations about a stable or unstable mean. The absence of 'free-running rhythms' associated with environmental isolation studies might reflect an ability to respond to environmental Zeitgerbers while unconscious. Temperature oscillations as well as 24 h rhythms were found even in the most severely brain-damaged patients, reflecting the resilience of the circadian oscillators in the brain to trauma.

Real-time monitoring of visual evoked potentials

Steady-state visual evoked potentials (SSVEP) were recorded in response to flashes from eyepatch-mounted light-emitting diodes during neurological surgery and in the intensive care unit. SSVEP were detected and measured with a microprocessor-based waveform correlator. The system enabled a continuous display, in real time, of SSVEP amplitude and latency. SSVEP amplitude and latency changes were monitored throughout a variety of surgical procedures. Some of these procedures directly affect the central visual pathway, some affect the central nervous system as a whole, while others do not affect central nervous system function. In addition, intensive care unit patients with a variety of intracranial pressures were monitored. The results of this study indicate that SSVEP recorded with this method showed changes in SSVEP within seconds of surgical and/or medical decompression of intracranial pressure and were sensitive to specific changes in the visual pathway. Surgical procedures that directly affected the visual system, or elevation of intracranial pressure, resulted in changes in SSVEP. In contrast, procedures that did not affect the functional integrity of the visual system did not affect the recordings.

[Brain abscess following skull traction]

A case of brain abscess developing after skull traction for fracture of the dens is presented. The abscess was most likely caused by retrograde septic thrombophlebitis via the superficial cortical veins. The abscess was drained and treatment with antibiotics was according to sensitivity on culture. 3 months after surgery there was mild residual paresis of the left hand. The need for close follow-up of patients prone to this complication is emphasized.

Effect of Histamine H2Receptor Antagonists on the Secretion of Cerebrospinal Fluid in the Cat

Following a recent report that epithelial cells of the choroid plexus possess histamine H2 receptors, the effect of cimetidine and ranitidine, histamine H2 receptor antagonists, on the secretion and electrolyte content of CSF was examined. Fifty cats were divided into one control (n = 6) and six experimental groups. CSF was collected by puncture of the cisterna magna following pentobarbital anesthesia, and its volume, concentrations of Na+, K+, Cl-, and pH were determined. Cimetidine or ranitidine (50, 20, or 10 mg/kg) was injected intravenously 2 h after the start of the test, and their concentrations were measured in hourly blood samples and in 30-min aliquots of CSF in the 50 mg/kg experimental groups. Whereas the secretion of CSF did not change over 6 h in the control group, it decreased significantly by 30-60 min after injection of cimetidine or ranitidine and remained low for the following 6 1/2 h in all experimental groups except the 10-mg ranitidine group. Peak cimetidine and ranitidine concentrations in CSF in the 50-mg experimental groups were noted 60 and 90 min, respectively, after intravenous injection. CSF electrolyte concentrations and pH did not change during the test in any group. We conclude that intravenous cimetidine or ranitidine can significantly reduce CSF secretion in the cat, possibly by competitive inhibition of the histamine effect on H2 receptors located on the choroid plexus epithelial cell, or by a direct effect on the capillaries of the choroid plexus.

Short latency trigeminal evoked potentials: normative data and clinical correlations

A very short latency trigeminal evoked potential (STEP) to electrical stimulation of the upper lip has been recorded from over the scalp. This potential consists of 5 distinct peaks within the 12 msec range. Normative data were obtained from 25 healthy volunteers. The impact of the stimulus rate and intensity on the response was studied in each subject. These results were compared to those of 19 patients suffering from lesions involving the trigeminal system in its peripheral aspect or the brain-stem. The STEP was consistently abnormal whenever the involved side was stimulated. Changes in peak latencies and in interpeak latency differences (IPLD) correlated well with clinical and radiological findings and improved with the removal of the offending lesion. The STEP proved to be a reliable method for evaluating the trigeminal system in its peripheral and central pathways; it may thus serve as an additional parameter for studying brain-stem functions.

The association between skull fracture, intracranial pathology and outcome in pediatric head injury

We prospectively studied 653 consecutive head-injured children (less than or equal to 14 years old) treated over a 54-month period (1984-88) at the Department of Neurosurgery of the Rambam Medical Center (Haifa, Israel). Demographic and clinical data were collected, the patients were divided into five age groups (birth to 2 years, 169; 3-5 years, 194; 6-9 years, 164; 10-12 years, 77; and 13-14 years, 49), and the information relative to each was then compared. All patients (except three who died on the operating table) underwent computed tomography (CT) scans; 225 (34.6%) had intracranial pathology, e.g. focal mass lesions, diffuse axonal injury, and subarachnoid haemorrhage. The rate of detected pathology increased with age. Skull fracture was documented in 468 (72%) patients. Craniotomies were done on 114 (17.5%) patients. After 3 months, the patients were classified as having good recovery (84.8%), moderate disability (5.5%), or severe disability (2.3%); 0.9% were in a vegetative state. The mortality was 6.6% (43 patients); of these, 39 (90.7%) had admission Glasgow Coma Scale scores below 8. In our area the annual incidence of neurosurgical hospitalization due to head injury in the pediatric group was 37.6 per 100,000 inhabitants per year. This study substantiates the findings of other series on the effects of prognosis of factors such as associated trauma, admission Glasgow Coma Score, mass lesions with persistent intracranial pressure elevation, or diffuse axonal injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Development of auditory brainstem evoked potentials in newborn infants: a three-channel Lissajous' trajectory study

Auditory brainstem evoked potentials (ABEP) were recorded from 50 newborns (35-43 weeks gestational age), using three orthogonal differential electrode pairs, in addition to the widely used vertex-mastoid derivation. Potentials were evoked by alternating polarity, 75 dBnHL clicks presented monaurally at a rate of 10/s. From the records of the three orthogonal electrode pairs (nasion-inion; vertex-spinous cervical process VII; left-right mastoids), Three-channel Lissajous' trajectories (3CLT) were derived and analyzed. 3CLT point-by-point, as well as segmental descriptors were compared with peak latencies of the vertex-mastoid derivation. Point-by-point 3CLT descriptors included apex amplitude, latency and orientation. Segmental descriptors included planar segment beginning latencies, duration and orientation. The interpretation of these results in relation to developmental aspects of the auditory system, as well as to the question of ABEP generators, is enhanced by using 3CLT descriptors of ABEP, which are more comprehensive than their single-channel counterparts. 3CLT apices correlated well with the Vertex-Mastoid defined peaks. Both peak and apex latency changes indicate that at the developmental stages surveyed in this study, development takes place in the more central portions of the pathway, whereas the peripheral portion is already relatively mature. The results also indicate a maturational change in the relative contributions of constituent generators of ABEP components.

Penetrating craniocerebral injuries in civilians

During a 6-year period (1984-89), 31 patients were treated at Rambam Medical Center with penetrating craniocerebral injuries (PCCI) not associated with military action. Eighteen (58%) patients died during their initial hospitalization; only two of them had admission Glasgow Coma Scale (GCS) above five. The admission GCS coupled with the mode of injury (type of missile and motivation of shooting) were valuable for early accurate prognosis assessment. Patients with admission GCS of 3 and 4 invariably died despite rapid treatment and attempted haematoma evacuation. The neurological status, CT appearance, as well as the motivation of shooting should be considered in order to assess accurately the possible outcome. Compared with our military series of 113 patients with PCCI, there were more extensive injuries, although the mean period until neurosurgical treatment was the same. Long-term complications connected to dural tears remote from the entrance wound occurred in three of the survivors.

Wartime neurosurgical experience in Lebanon, 1982-85. II: Closed craniocerebral injuries

This report presents 64 patients who sustained military-related closed craniocerebral injuries during the Lebanon conflict of 1982-85, all of whom underwent CT scanning at the initial assessment. Of these, 59% required surgery for removal of hematomas, depressed fractures and for monitoring intracranial pressure, in addition to intensive care management of elevated intracranial pressure and associated insults. CT scan revealed brain concussion only in 23%, depressed fracture in 9%, brain contusion alone in 17%, extracerebral hematomas in 17%, intracerebral hematomas in 11%, and diffuse axonal injury in 22%. Overall mortality was 19%, and the outcome was good in 69%. Various factors affecting survival are discussed, and our findings are compared with those in the literature concerning closed head injuries among civilians. Attention is drawn to the high proportion of diffuse brain injury due to blasts caused by side mines. Despite continued efforts to hasten evacuation from the field and improve the management of warfare-related head trauma, the outcome is still far from satisfactory.

Wartime neurosurgical experience in Lebanon, 1982-85. I: Penetrating craniocerebral injuries

The present report analyzes 116 penetrating wounds of the brain sustained during warfare in Lebanon during 1982-85. Two basic mechanisms of injury were encountered: high-velocity bullets, and shrapnel and stones from explosive devices; and in one case a radio antenna penetrated the head through the orbit. The site of impact was at the convexity in 87% of cases and at the base of the skull in the remaining 13%. Surgery was performed in 83% of the patients: debridement-craniotomy in 73%, burr hole for intracranial pressure monitoring only in 6% and scalp closure only in 4%. The remaining 17% did not require surgery because of transbasal penetration without intracranial mass (10%) or due to moribundity. Indriven bone or foreign body fragments were removed only if readily accessible. The mortality rate was highest among patients with a Glasgow Coma Scale of less than or equal to 4 on arrival, after high-velocity bullet wounds, when the intracranial path was multilobar or transventricular, and when associated lesions were accompanied by shock. A follow-up study of the 49 Israeli survivors for almost 6 years revealed intracerebral-retained bone fragments in 48%, but these did not result in increased immediate or late complications (e.g., infection, epilepsy). These results support our conservative approach. Since all victims of penetrating head injuries were evacuated from Lebanon to Rambam Medical Center, Haifa, our report can serve as an estimation of the incidence of penetrating brain wounds and their burden on a front-line hospital.

Diffuse axonal injury: analysis of 100 patients with radiological signs

One hundred patients with head injuries who showed diffuse axonal injury on computed tomographic scans are reported. Evaluation of the Glasgow Coma Score, pupillary signs, and computed tomographic findings on admission led to an improved ability to forecast outcomes. Our relatively good results as compared with other series, can be explained by the high proportion of children and by the liberal use of computed tomography to evaluate head injuries, thus revealing that concussion may sometimes be regarded as an early form of diffuse axonal injury.

[Head and brain injuries in bicyclists]

44 patients were hospitalized for neurosurgical care after bicycle accidents during a period of 50 months. Ten times as many were injured in other types of road accidents. 42 of the 44 cases had brain injury, with a mean hospitalization of 9.7 days. A third needed operation and a fourth were discharged with residual neurological deficits. The low incidence of 0.95 cases per 100,000 per year led us to examine the factors which limit the use of bicycles in our region. The severity of the injuries in our cases was much greater than in those in other countries, with a mean injury severity score of 14.2. None of our cases had worn a protective helmet, and we join in the world-wide plea for an educational campaign for their use.

Penetrating craniocerebral injuries in the Israeli involvement in the Lebanese conflict, 1982-1985. Analysis of a less aggressive surgical approach

From June, 1982, through June, 1985, 113 patients were evacuated to Rambam Maimonides Medical Center with penetrating craniocerebral injuries sustained in ongoing military hostilities in Lebanon. Two factors distinguished this group of patients from those presenting in earlier conflicts: 1) this was the first large series in which computerized tomography (CT) was routinely used to initially evaluate combat head injuries; and 2) in an effort to preserve maximum cerebral tissue, intracranial debridement was significantly less vigorous than that advocated during the Korean or Vietnam conflicts. No efforts were made to locate or remove in-driven bone or metal fragments visualized on CT unless they readily presented themselves on gentle irrigation. In fact, it was elected to treat a number of patients without intracranial hematomas nonoperatively. The acute outcome was quite similar to that reported in Vietnam series in respect to both complications and mortality. Of the 83 survivors, 46 were Israeli citizens and thus were available for follow-up review. These 46 patients were reevaluated in late 1988, a mean follow-up period of 5.9 years. None had died in the interim; 10 had developed chronic seizure disorders, and there was one case of delayed meningitis in a patient with no retained fragments. Repeat CT scans were performed on 43 patients; 22 (51%) were found to have retained intracranial bone fragments. No relationship existed between the presence of retained fragments and the development of either a seizure disorder or an infection of the central nervous system. These findings suggest that not only is it unnecessary to reoperate for retained bone fragments, but it may also be possible to temper the initial debridement in an effort to preserve additional cerebral tissue.

Head trauma in northern Israel: incidence and types

A descriptive epidemiological study of neurotraumatology was undertaken over a 4.5-year period at a regional hospital with a referral base of 1,200,000 residents served by a single neurosurgical department. Neurosurgical evaluations and treatments were given to 1,370 patients in this period. The data base consists of demographic, clinical and radiological features at the time of admission, as well as the hospital course through discharge. The crude incidence rate was 25.2 +/- 3.1 cases per 100,000 person-years (similar to that of three neurosurgical units in Scotland). Age adjustment showed almost twice this rate at the two extremes of age and a smaller elevation in early adulthood. The crude incidence was 36.9 for males and 13.4 for females (p less than 0.01). Age-specific incidence rates in Jews compared to other ethnic groups were reported. Falls had an incidence of 12.8 (51%), road accidents 9.0 (35.7%) and assaults 2.3 (9%) per 100,000 person-years. Other causes were accidents during work or sport and suicide. The rate of brain pathology as revealed by computerized tomography steadily increased from 19% in childhood to 71% in the elderly with a mean of 41.8%. A similar increasing trend with age was found in the rate of intracranial mass lesions (mean 28.3%), impaired consciousness (30.4%) and mortality (13%).

Sacrococcygeal extradural ependymoma

A case of lumbosacral extradural myxopapillary ependymoma is reported. The clinical, embryologic, and therapeutic features of this rare lesion are presented. The unusual entity is discussed in the light of previous experience with extradural ependymoma in the lumbosacral region.

Quantitative bone scintigraphy using SPECT

A quantitative single photon emission computed tomography (SPECT) technique for measuring radiopharmaceutical uptake in humans has been applied to bone scintigraphy. The method was validated by comparing SPECT measured percent of injected [99mTc]MDP in 16 normal skulls with well counter measurements of samples of the same bones obtained at surgery. A very good correlation (r = 0.96) was found. A very good interobserver correlation (r = 0.99) and agreement were also obtained when using quantitative bone scintigraphy (QBS). Control SPECT studies of uptake in the right and left iliac bones and the right and left sacroiliac regions in each patient showed no significant differences between the contralateral sides. Studies done in seven subjects at 2 and 4 hr after the same injection and in nine subjects 4 to 8 mo later in the same subjects showed a very good agreement and no significant differences between the two measurements were found. QBS is suggested as an accurate and reproducible index for assessment of the mass of remodeling bone. Preliminary results showed differences in QBS of normal subjects at different ages. A group of 68 young patients aged 18-26 yr showed a significant higher QBS (p less than 0.001) when compared to an older group of 62 patients aged 50-85 yr. There was, however, a wide range of uptake values for the same bone in the same group, suggesting that the method should best be used for following individual patients over time.