Dibutyryl cyclic adenosine 3',5'-monophosphate: its role in regulation of cat brain extracellular fluid

The role of dibutyryl cyclic adenosine 3',5'-monophosphate (db cAMP) in influencing the water content of the cat's gray and white matter was evaluated by intracoritcal injection of 20 micrio L of 2 x 10(-1) to 2 x 10(-6)M solution of db cAMP. Cholera toxin, a stimulator of adenylate cyclase, also was tested. Concentrations of db cAMP less than 10(-3)M failed to produce significant change in brain water content, while concentrations greater than 10(-2)M produced 31.5% +/- 8% and 17.3% +/- 3.6% increases in white matter volume, respectively (P less than .05). Cholera toxin did not increase brain water levels. These results are discussed in relation to the pathophysiology of brain edema.

The anatomy of the so-called "articular nerves" and their relationship to facet denervation in the treatment of low-back pain

Disections of the dorsal rami of L1--5 were performed in human cadavers, and the course of the dorsal rami, their branches, and the innervation of the zygapophyseal joints in the lumbar region were specifically studied. At the L-1 through L-4 levels, the dorsal rami divide into medial and lateral branches within the intertransverse ligaments. Each medial branch runs across the root of the adjacent superior articular process. At the caudal edge of the process, the branch turns medially beneath the mammillo-accessory ligament. Beneath the mammillo-accessory ligament, medial branches occur that innervate the adjacent zygapophyseal joint, and distal zygapophyseal branches arise at the laminar level to innervate the next lower joint. The L-5 dorsal ramus runs along a groove between the ala of the sacrum and its superior articular process. A the caudal edge of the articular process, the ramus divides into medial and lateral branches, and the medial branch supplies the L5--S1 articulation.

Capillary ultrastructure in human metastatic brain tumors

The ultrastructural characteristics of blood vessels within 18 metastatic neoplasms of the brain have been studied. The abnormal permeability to protein-bound tracers was found to be related to defective capillary endothelium. Abnormalities include gap functions, fenestrations of membranes, and open normal junctions. The abnormal capillaries had the character of capillaries from current tissue. Endothelium cell abnormalities were not found in surrounding edematous brain.

Familial intradural arachnoid cysts. Report of two cases

✓ Two cases of intradural arachnoid cysts are reported in one family. The propositus was a 27-year-old woman with right inframammillary radicular pain and subjective weakness of the lower extremities. Her 57-year-old father was admitted with a progressive, painless paraparesis of 6 years' duration. Intradural arachnoid cysts, at T8–9 and T5–6, respectively, were found in both patients at the time of exploration.

Surgical postoperative bleeding associated with aspirin ingestion. Report of two cases

Two patients are reported in whom repeated postoperative hematomas appeared to be secondary to aspirin-induced platelet defect. Routine bleeding and clotting studies will not demonstrate this platelet-induced coagulopathy. A previous history of massive aspirin ingestion makes such a coagulopathy a serious consideration, but the platelet defect may occur with small doses of aspirin. Such aspirin ingestion should be viewed with great concern by the neurosurgeon. The defect is treatable by platelet transfusion.

Thalamic EEG recordings in patients with chronic pain

Thalamic EEG recordings were made in 10 patients; the therapeutic goal of the implantation was the electrical stimulation treatment for pain. The patients' ages ranged from 37 to 72 years; seven patients had thalamic pain (Dejerine-Roussy syndrome), two had chronic spinal arachnoiditis and one had facial anaesthesia dolorosa. Platinum-iridium electrodes were stereotaxically inserted; the ventrobasal complex of the thalamus including the ventral posterior zone was the target of the implant. Excessive thalamic slowing was found in four of seven patients with Dejerine-Roussy syndrome and also in two of three cases with other causes of pain. One patient had marked rhythmical intermittent delta activity in the thalamus which was often triggered by arousing stimuli. Thalamic spindle activity was sometimes noted without concomitant spindle activity on the scalp and would occasionally occur in states of early drowsiness.

Enlarging optic chiasmal glioma with stable visual acuity

A 13 1/2-year-old girl with stable, reduced visual acuity, nystagmus and Small, pale optic discs initially noted at age nine months, developed signs and symptoms of increased intracranial pressure. At craniotomy, an intrinsic glioma of the optic chiasm and both optic nerves extended into both frontal lobes, the hypothalamus and the third ventricle.

Tumor imaging with x-rays using macrophage uptake of radiopaque fluorocarbon emulsions

Radiopaque fluorocarbon (RFC) emulsions were prepared with small particle size and high concentration of the fluorocarbon. When RFC emulsions were injected intravenously in hamsters, rats, and mice with eight types of malignant tumors, the tumors became radiopaque, except in the mice with spontaneous teratoma of the ovaries. Tumors as small as 3 to 4 mm could be defined radiographically using routine x-ray techniques. The tumors remained radiopaque for days to weeks after injection. Light and electron microscopy revealed characteristic fluorocarbon vacuoles primarily in the tumor macrophages. Thus RFC emulsions may be useful in detection of malignant tumors.

Chronic stimulation via percutaneously inserted epidural electrodes

Thirty-one patients suffering from intractable pain associated with chronic low back syndrome, cancer, and other disorders have been studied after an average of 6 months of treatment by electrical stimulation of the spinal cord applied using electrodes inserted through a Touhy needle into the epidural space. As judged by three different subjective rating methods, epidrual stimulation successfully relieved otherwise intractable chronic pain in from 23 to 26 of the 31 patients. Reported improvements in the ability to perform various everyday activities, and elimination of drug usage by many patients, corroborated this finding.

Uses of percutaneous electrical stimulation of the nervous system

Temporary percutaneous electrical stimulation of peripheral nerves and the spinal cord is a valuable screening technique. This approach will provide a much higher success rate for identifying those patients suitable for a permanently implanted stimulation system. The system appears to be the treatment of choice for chronic, intractable pain caused by nerve injury. The author presents his surgical procedures for stimulation of peripheral nerve and spinal cord. A summary of clinical results is discussed.

Electrical stimulation for the control of pain

Electrical stimulation for the control of pain is now a well accepted therapeutic modality. Transcutaneous application of electrical stimulation is the most common technique employed and has been used to treat chronic pain, acute surgical pain, and acute pain of other origins. Percutaneous application of electricity to the nervous system through needles electrodes is useful in predicting the efficacy of implantable stimulators and has served the same function as diagnostic nerve block. Implantable stimulators have been used for stimulation of peripheral nerves, the anterior and posterior surfaces of the spinal cord, and the brain. Peripheral nerve stimulators are the most efficacious of the implantable devices. They are used specifically for pain of peripheral nerve injury origin. Their use for pain outside the distribution of the nerve stimulated is not yet proved.

Recirculatory spinal subarachnoid perfusions in dogs: a method for determining CSF dynamics under non-steady state conditions

Open-ended ventriculocisternal perfusion techniques for determining cerebrospinal fluid production and absorption rates are severely restricted by the absolute requirement that steady state conditions be present. A new closed recirculatory spinal perfusion technique is described. Because steady state equilibrium is not necessary, numerous determinations at multiple intracranial pressures or under varied experimental conditions are possible within relatively brief perfusion periods. Cerebrospinal fluid (CSF) and nondiffusible albumin tracer are rapidly recirculated through the spinal subarachnoid space in a cephalad direction. The concentration of fluorescein-tagged albumin is continuously monitored as the CSF is circulated through a fluorometric flow cell. Measured continuously, intracranial pressure (ICP) is regulated by changing the volume of the external perfusion circuit with a syringe pump connected in series to the recirculatory spinal perfusion. CSF formation and absorption rates are calculated from measurements of albumin concentration, concentration changes with time, ICP, syringe pump infusion rate, and the external perfusion circuit volume. In dogs, data can be collected after only 45 minutes for mixing; perfusions at four or five intracranial pressures in addition to normal resting pressure can be completed within 2 to 3 hours. The data from 15 perfusions in 14 dogs are presented. The method provides normal resting pressure values of CSF production and absorption consistent with those values in the literature determined by traditional ventriculocisternal perfusion techniques. Determinations at multiple intracranial pressures suggest a proportional relationship between absorption and ICP. No consistent acute change in CSF formation with pressures to 50 mm Hg can be inferred from these data.

Use of microfibrillar collagen as a topical hemostatic agent in brain tissue

Microfibrillar collagen, a recently introduced topical hemostatic agent, was used to obtain hemostasis in suction-evacuation lesions of canine cortex. Gelatin foam was used as a control in identical lesions on the opposite side. Microfibrillar collagen was found to be faster acting and more effective than gelatin foam. Histological evaluation of the lesions at 2,4, and 6 months postoperatively showed no significant difference in the amount or type of tissue reaction to the two agents.

Perfluoroctylbromide as a diagnostic contrast medium in gastroenterography

The efficacy and safety of perfluoroctylbromide as a diagnostic contrast medium for gastroenterography was studied in laboratory animals. It was found that perfluoroctylbromide possesses excellent coating properties and a short transit time in the gastrointestinal tract. The conscious animals tolerated 64 ml/kg without any toxic manifestations. Thorough hematologic, serologic and histologic examinations showed no evidence of any adverse effects. Perfluoroctylbromide may be especially useful in patients with advanced inflammatory lesions of the gastrointestinal tract or in those with risk of aspiration of contrast medium into the lungs during gastroenterographic examinations.

Chronic dorsal column stimulation via percutaneously inserted epidural electrodes. Preliminary results in 31 patients

31 patients suffering from intractable pain associated with chronic low back syndrome, terminal cancer, and other disorders have been studied after an average 6 months' treatment by electrical stimulation of the spinal cord applied via electrodes inserted through a Tuohy needle into the epidural space. As judged by three different subjective rating methods, epidural stimulation successfully relieved otherwise intractable chronic pain in from 23 to 26 of the 31 patients. Reported improvements in the ability to perform various everyday activities, and elimination of drug usage by many patients, corroborate this finding. The side effects of stimulation, both as reported subjectively and as measured objectively by sensory testing, were not clinically significant. Spontaneous electrode displacements, leading to loss of analgesia and requiring minor surgery for repositioning, were encountered frequently, as were lead wire failures necessitating replacement. The partially implanted, externally powered stimulation system presently in use also suffers from problems of reliability and convenience to the patient.

Transnasal transsphenoidal approach to the sella

The transnasal transsphenoidal approach to the sella turcica has been refined and perfected through advances in medicine and technology. Originally performed for excision of pituitary adenomas, its present primary use is pituitary ablation is hormonally dependent diseases. Our study of 55 patients who have undergone this procedure during the years 1970-1975 demonstrates that this microscopic technique gives excellent exposure and visualization of intrasellar contents. Our method gives excellent exposure and visualization of intrasellar contents. Our method with several instrument modifications is discussed. It is technically an easy procedure with a minimum of morbidigy and mortality.

Peripheral nerve stimulation in the treatment of intractable pain

Peripheral nerve stimulating devices were implanted for pain control in 33 patients with a variety of disabling chronic pain conditions, which had persisted despite usual medical and surgical therapy. The implants were placed on major nerves innervating the area of the patient's pain. Records were obtained of each patient's stated relief from pain produced by nerve stimulation, along with assessments of narcotic withdrawal, ability to return to work, sleep pattern, and relief from depression. Based on these five criteria 17 patients were judged to be treatment failures, while eight patients had excellent results, and seven had intermediate results. Twelve of the failures were in patients with either low back pain with sciatica, or pain from metastatic disease. The most dramatic successes occurred in patients with peripheral nerve trauma. The incidence of complications has been low, and two patients have used the stimulator for 5 years without adverse effects. Techniques of peripheral stimulator implantation, possible mechanisms of action, and conclusions regarding peripheral nerve stimulation in the treatment of chronic pain are discussed.

Biological disposition of perfluoroctylbromide: tracheal administration in alveolography and bronchography

Perfluoroctylbromide, given tracheally either as neat liquid in alveolography or as 10:1 emulsion in bronchography, was cleared roentgenologically from the lungs within 24 hours. Quantitative analysis was performed on a gas chromatograph. The rats were given either 2 ml/kg of neat liquid or 0.4 ml/kg emulsion. One per cent of the neat liquid and 8% of the emulsion were recovered from the tissues respectively 24 hours later. The lungs had the largest amount followed by the intestine, adipose tissue and lymph nodes. Dogs were sacrificed at various intervals following 4 ml/kg of neat liquid or 2 ml/kg of emulsion. Less than 1% of the dose was found in the tissues at 24 hours. A similar pattern of perfluoroctylbromide distribution was observed as in the rats. The tissue contents of perfluoroctylbromide at three months were below the limit of detection. The perfluoroctylbromide levels in the blood and urine of dogs and human volunteers were either non-detectable or barely detectable over a 48-hour period.

Perfluoro carbon bromides as contrast media in radiography of the central nervous system. A preliminary experimental report

A preliminary investigation of the properties of perfluorooctyl bromide in the subarachnoid space revealed this compound to have suitable attenuation capacity and advantageous physical and biologic properties for demonstration of the brain and spinal cord. No acute or chronic neurotoxicity was encountered. Microscopy demonstrated evidence of chronic inflammatory changes subsequent to long term exposure to the compound. It was concluded that the medium was superior to iodophendylate in several respects and that it may provide an alternative to water-soluble contrast media. Perfluorohexyl bromide proved unsuitable for neuroradiologic use because of formation of excessive amounts of non-absorbable gas, leading to high subarachnoid pressure and severe neurologic deficits.

Stimulation of the posterior columns of the spinal cord for relief of intractable pain

Sixty-nine patients with chronically incapacitating pain were treated with an implantable stimulator over the posterior columns of the spinal cord. Evaluations at 24, 30 and 34 months showed a progressive decrease in the number of patients considered to have an excellent result. Evaluation of 60 patients with pain of benign origin after implantation of the stimulating device showed only ten patients who could be considered to have an excellent result on the basis of their own report of pain relief. The most common failure of the stimulating devices was failure of stimulation into a painful part.

Distribution of activity in spinal pathways evoked by experimental dorsal column stimulation

Experiments were performed in rhesus monkeys to determine the distribution of activity evoked in spinal pathways by dorsal column stimulation. It was shown that many pathways in both the dorsal and ventral quadrants of the cord can be activated either directly or transsynaptically by stimulation with electrodes of the type implanted clinically. Moreover, the transsynaptically evoked responses recorded in each quadrant had somewhat different characteristics. Therefore, since the activation of each group of pathways may have differing effects in modifying the preception of noxious stimuli, the authors believe that changes in electrode position and stimulus parameters may be important in obtaining the therapeutic value of spinal cord stimulation for relief of pain.

Giant arteriovenous malformations of infancy and childhood

✓ Twelve patients are presented with giant arteriovenous malformations of the brain requiring therapy in the neonatal or infant period. Eight patients were operated on, and six survived with no neurological deficit. Four patients were not operated on and all died. The diagnostic clinical triad of enlarged head, cranial bruit, and cardiac failure or enlargement is described, and angiographic characteristics and surgical therapy discussed.

Electrical stimulation for relief of pain from chronic nerve injury

✓ Ten patients with various kinds of nerve injury pain were treated by stimulation from subcutaneously implanted electrodes placed on the nerves. Placement of the electrode was proximal to the site of injury in nine patients and distal in one. Pain relief was complete in six of the 10 patients. Of the nine patients addicted to narcotics, seven were successfully withdrawn. In one patient the stimulation totally failed to relieve the pain, and in one the pain was made worse.

Transcallosal removal of cranio-pharyngiomas within the third ventricle

✓ Six cases of craniopharyngioma located wholly, or largely, within the third ventricle are described; these include four adults with tumors completely within the ventricular system and two children with recurrent tumors primarily within the third ventricle. Four of these patients were operated on by a transcallosal approach. Gross total removal was possible in all patients, but two have suffered recurrence and only one is alive and tumor-free. There were no signs or symptoms present preoperatively that allowed the intraventricular nature of the neoplasm to be correctly diagnosed. Air encephalography provided definitive tumor localization in each case. Three patients died of massive gastrointestinal hemorrhage in the immediate postoperative period. The surgical technique of transcallosal approach for removal of these neoplasms is described in detail.

Vascular ultrastructure in human meningiomas and schwannomas

✓ Nineteen meningiomas and schwannomas have been studied by fluorescence microscopy and electron microscopy. Increased cerebrovascular permeability to protein was demonstrated in each tumor. The anatomical explanation for this increased permeability to protein was found in open endothelial cell junctions, gaps between endothelial cells, and fenestrations in capillary endothelial membranes.

Interruption of double inferior vena cava for prevention of pulmonary embolism

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Subdural hematoma as a complication of shunting procedures for normal pressure hydrocephalus

✓ The authors report five patients with normal-pressure hydrocephalus (NPH) who developed subdural hematomas following shunt procedures. None of the hematomas was directly related to surgery, and all appeared after the patients had shown initial clinical improvement; one was conceivably related to trauma. These patients appear to be especially susceptible to this complication, as the high incidence of 5 of 24 cases is not seen in the treatment of high-pressure hydrocephalus. The symptoms and signs of this complication, diagnosis, and treatment are described and emphasized. It is concluded that shunting procedures for NPH should not be undertaken lightly, and rigid criteria should be applied in the selection of patients to exclude other causes of dementia.

Hyperoxia of cerebral venous blood and cisternal cerebrospinal fluid following arterial air embolism

✓ Oxygen tension and acid-base parameters of cerebral venous blood and cisternal cerebrospinal fluid, as well of femoral arterial blood, were studied in 14 dogs following injection of varying amounts of room air into the right vertebral artery. Acute elevations in oxygen tension were demonstrated in both cerebral venous blood and CSF, whereas hypoxemia occurred concomitantly in systemic arterial blood. Post-embolic increases in carbon dioxide tension with reciprocal diminutions in pH were evident in all sampling sites. The pathophysiological bases for these air-induced alterations are discussed.