New non-invasive sonographic modality for intracranial pressure/volume monitoring

INTRODUCTION: The wide use of intracranial pressure and cerebral perfusion pressure monitoring has improved the management of patients with severe head injuries. The rare but worrying complications associated with the application of such monitoring makes the idea of a non-invasive method of monitoring very attractive. MATERIALS AND METHODS: A new non-invasive ultrasonographic technology was used to measure cerebral perfusion pressure in 27 normal volunteers. The average monitoring time was 45.3+/-0.2 min, and the average perfusion pressure recorded was 77.4+/-0.3 mmHg. No complications were reported during the procedure, which was performed while the subjects were in regular ward beds. CONCLUSION: The non-invasive character of this method could extend the use of cerebral perfusion pressure measurement to several other neurosurgical entities, such as hydrocephalus, pseudotumor cerebri, chronic headache, and spinal cord injuries.     

Characterization of the human neutrophil C1q receptor and functional effects of free ligand on activated neutrophils

The partial characterization and expression of the C1q receptor (C1q-R) in relation to other complement receptors present on the surface of neutrophils has been examined, as well as the effects of free C1q on cell function. A polyclonal anti-C1q-R antibody recognizes a 68-kD neutrophil surface protein. C1q-R expression was not upregulated upon warming, priming, or exposure to FMLP, but decreased after exposure to phorbol myristate acetate (PMA), because of shedding of the receptor into the extracellular medium, as detected by enzyme-linked immunosorbent assay. CR3 and CR1 expression was upregulated from intracellular pools after cell stimulation by PMA. No evidence of intracellular pools of C1q-R was found, as assessed by immunoblotting of subcellular fractions. But C1q-R appeared to be expressed early in cell differentiation, was detected on undifferentiated HL-60 cells, and like CR3 expression, increased upon 5 days differentiation towards a neutrophil lineage. However, C1q-R expression decreased upon additional culture, whereas CR3 expression continued to increase. A large variation in the percentage of peripheral cells expressing C1q receptors in donors was observed, ranging from 13% to 100%, contrasting with CR3 receptors that exhibited less variability. Interactions between free monomeric C1q and neutrophils were also studied. Incubation of stimulated neutrophils with 10 to 100 micrograms/mL C1q resulted in a further increase in CR3 expression and adherence to albumin-coated surfaces. Staphylococci opsonized with low quantities of C1q (0.1 to 1 microgram/mL) mediated a moderate and sustained respiratory burst in neutrophils, whereas a burst of similar magnitude was generated only with free C1q at concentrations 10- to 100-fold higher. Stimulation was only partially inhibited if cells were first treated with anti-C1q-R antibody, suggesting other C1q binding proteins may be present on the cell surface. In summary, neutrophil C1q receptor is approximately 68-kD, exhibits varying expression on different subjects, and is not upregulated from intracellular stores on exposure to soluble stimuli. Stimulated, but not resting, neutrophils selectively respond to raised levels of free C1q, resulting in altered cell function and enhanced CR3 receptor expression. These studies thus suggest complex roles for C1q in neutrophil function.     

Outcome of patients undergoing gamma knife stereotactic radiosurgery for medically refractory idiopathic trigeminal neuralgia: Medical College of Georgia's experience

Gamma knife radiosurgery represents an established treatment option for the management of medically refractory trigeminal neuralgia (TN). In our current communication we present our experience in radiosurgically treating patients with idiopathic TN. Over a period of 5 years, 77 patients underwent gamma knife radiosurgery. The patients were divided into 2 groups based on their previous surgical treatment. In the group of patients with no previous surgeries, the initial response rate was 92.4% (48/52 patients), while in the group with previous surgeries it was 84% (21/25 patients). The excellent outcome rates (complete pain relief with no pain medications) at the completion of 1, 2 and 3 years after treatment for the group with no previous surgeries were: 80.8% (42/52 patients), 69.2% (36/52 patients) and 53.8% (28/52 patients), respectively. The respective excellent outcome rates for the group of patients with previous surgeries were: 64% (16/25 patients), 44% (11/25 patients) and 12% (3/25 patients). The good outcome rates at the completion of 1, 2 and 3 years after treatment for the group with no previous surgeries were: 7.7% (4/52 patients), 11.5% (6/52 patients) and 19.2% (10/52 patients). The respective percentages of good outcome for the patients with previous surgery were: 12% (3/25 patients) at 1 year, 16% (4/25 patients) at 2 years and 32% (8/25 patients) at the completion of 3 years after treatment. The most commonly encountered complication in our series was the development of facial numbness. Our findings confirm previous reports that the presence of preceding surgical interventions represents a negative long-term outcome factor. However, gamma knife radiosurgery constitutes a safe and efficient minimally invasive treatment option for patients with idiopathic TN.     

Review of the literature regarding the relationship of rebleeding and external ventricular drainage in patients with subarachnoid hemorrhage of aneurysmal origin

Acute hydrocephalus is a well-documented complication of subarachnoid hemorrhage. The insertion of external ventricular drainage (EVD) has been the standard of care in the management of this complication, aiming primarily at immediate improvement of the clinical condition of these patients, making them more suitable candidates for surgical or endovascular intervention. In our current communication, we review the pertinent literature regarding the relationship of rebleeding and EVD. Several studies have implicated a significantly increased risk of rebleeding in patients with EVD, compared with patients without it. Abrupt lowering of the intracranial pressure could lead to rebleeding due to decreased transmural pressure or removal of the clot sealing the previously ruptured aneurysm. However, a variety of parameters that could affect the rebleeding rate, such as the timing of surgery, the timing and duration of drainage, the size of the aneurysm, as well as the severity of the initial hemorrhage, do not seem to have been adequately explored in the majority of these studies. In addition, a number of clinical trials have failed to provide evidence for the negative role of EVD in the development of rebleeding. Conclusively, further long-term multi-center studies are required in order to establish the exact nature of the relationship between EVD and rebleeding after aneurysmal subarachnoid hemorrhage.A commentary on this paper is available at     

Implanted subdural electrodes: safety issues and complication avoidance

Invasive electroencephalography via subdural implanted electrodes is essential for the identification and localization of the epileptogenic focus in a large percentage of cases of medically refractory epilepsy. The implantation of subdural electrodes constitutes a widely used method for the preoperative investigation of these patients. However, their implantation has been associated with the occurrence of some rare but potentially serious complications. This article systematically reviews the literature regarding safety issues, potential complications, and complication avoidance strategies associated with the implantation of subdural electrodes. Knowledge of all the reported complications may help in their early detection and their prompt management.     

Usefulness of radionuclide angiocardiography in predicting stenotic mitral orifice area

Fifteen patients with pure mitral stenosis (MS) underwent high-temporal-resolution radionuclide angiocardiography for calculation of the ratio of peak left ventricular (LV) filling rate divided by mean LV filling rate (filling ratio). Whereas LV filling normally occurs in 3 phases, in MS it is more uniform. Thus, in 13 patients the filling ratio was below the normal range of 2.21 to 2.88 (p < 0.001). In 11 patients in atrial fibrillation, filling ratio divided by mean cardiac cycle length and by LV ejection fraction provided good correlation (r = 0.85) with modified Gorlin formula derived mitral area and excellent correlation with echocardiographic mitral area (r = 0.95). Significant MS can be detected using radionuclide angiocardiography to calculate filling ratio. In the absence of the confounding influence of atrial systole calculation of 0.14 (filling ratio ÷ cardiac cycle length ÷ LV ejection fraction) +0.40 cm² enables accurate prediction of mitral area (±4%). Our data support the contention that the modified Gorlin formula, based on steady-state hemodynamics, provides less certain estimates of mitral area for patients with MS and atrial fibrillation, in whom echocardiography and radionuclide angiocardiography may be more accurate.     

Paediatric dacryocystorhinostomy

Of 258 cases of dacryocystorhinostomy performed on children in the period September 1981 to September 1991, 130 were for simple, unresolved congenital nasolacrimal duct obstruction. Other indications for surgery included punctal agenesis, lacrimal fistula, post-traumatic and post-inflammatory canalicular obstruction. Of 177 children without canalicular pathology, 171 (96%) were relieved of symptoms with one operation, without canalicular intubation. Of 81 cases with canalicular disease, 55 of 70 (79%) who underwent DCR plus canalicular intubation, and 10 of 11 who underwent DCR plus Lester-Jones tube, were substantially improved with one operation. No child required peroperative or postoperative blood transfusion. Dacryocystorhinostomy in childhood, in experienced surgical hands, is a safe procedure, achieving relief of symptoms in most cases, particularly in the absence of canalicular disease.     

Clinical implications of quantitative infrared pupillometry in neurosurgical patients

Pupillometry has been widely employed in the evaluation of a large number of pathological conditions, including intracranial pathology. The recent introduction of a portable, user-friendly, infrared pupillometer (ForSite, NeurOptics Inc., Irvine, CA) has enabled the accurate and reproducible measurement of several pupillary parameters, such as maximum and minimum apertures, constriction and dilation velocities, and latency period. It should be noted that various clinical conditions, especially neurological and ocular diseases, as well as numerous medications, may interfere with the measurements. Furthermore, a number of physiological parameters, such as the intensity of retinal illumination, the level of patient's alertness, the intensity of ambient light, as well as the time of day that the examination is performed may alter the obtained values. The potential implications of pupillometry in the clinical assessment of neurosurgical patients, including its complex relationship to intracranial pressure changes, mandate the undertaking of prospective clinical studies validating the clinical significance of this noninvasive, diagnostic modality.