Biomedical subjects
Publications and source records attributed to F C Vinas.
Syrinx are often related to trauma, tumours or abnormalities of the craniocervical junction. Only a few cases of spontaneous resolution have been reported in the literature. The authors present a case of spontaneous resolution of a cervical syrinx, and analyse the possible physiopathological mechanisms leading to resolution. Other similar cases reported in the literature were collected and analysed.
The spontaneous resolution of herniated cervical discs has not been previously well documented. The authors analysed four cases who underwent spontaneous resolution of herniated cervical discs, and all other cases reported in the literature. A complex physiopathologic mechanism that includes the release of basic fibroblast grow factors, endothelial cell proliferation, chemotaxis of inflammatory cells into the disc fragment, foreign body inflammatory reaction, neovascularization and phagocytosis and accounts for the resorption of herniated discs is reviewed.
Sarcoidosis is a multisystemic disorder characterised by the presence of multiple noncaseating granulomas. Clinically recognisable nervous system involvement occurs in 5-16% of patients with sarcoidosis. However, the incidence of subclinical neurosarcoidosis may be higher. The following article presents a review of the disease, including its pathophysiology, clinical and radiological characteristics and treatment. Neurosarcoidosis should be included in the differential diagnosis of infectious and noninfectious neurological syndromes.
Since the original description by Liliequist only a few microanatomical studies of the Liliequist membrane have been performed. These studies contain some discrepancies in the description, boundaries, and attachments of the membrane. Using a surgical microscope the authors examined the microsurgical anatomy of Liliequist's membrane and surrounding neurovascular structures in twenty adult brains injected with silicone rubber, with special emphasis given to the analysis of controversial details. This description is intended as an aid for neurosurgeons performing neuroendoscopic procedures.
BACKGROUND: Decompressive craniectomy has historically served as a salvage procedure to control intracranial pressure after severe traumatic brain injury. We assessed the safety and feasibility of performing craniectomy as the initial surgical intervention. METHODS: Of 29 consecutive patients undergoing emergent decompression for severe traumatic brain injury with horizontal midline shift greater than explained by a removable hematoma, 17 had traditional craniotomy with or without brain resection and 12 underwent craniectomy. RESULTS: The craniectomy group had lower Glasgow Coma Scale scores at surgery (median, 4 vs. 7; p = 0.04) and more severe radiographic injuries (using specific measures). Mortality, Glasgow Outcome Scale scores, Functional Independence Measures, and length of stay in both the acute care setting and the rehabilitation phase were similar between the surgical groups. CONCLUSION: Despite more severe injury severity, patients undergoing initial craniectomy had outcomes similar to those undergoing traditional surgery. A randomized evaluation of the effect of early craniectomy on outcome is warranted.
OBJECT: The poor prognosis for traumatic acute subdural hematoma (ASDH) might be due to underlying primary brain damage, ischemia, or both. Ischemia in ASDH is likely caused by increased intracranial pressure (ICP) leading to decreased cerebral perfusion pressure (CPP), but the degree to which these phenomena occur is unknown. The authors report data obtained before and during removal of ASDH in five cases. METHODS: Five patients who underwent emergency evacuation of ASDH were monitored. In all patients, without delaying treatment, a separate surgical team (including the senior author) placed an ICP monitor and a jugular bulb catheter, and in two patients a laser Doppler probe was placed. The ICP prior to removing the bone flap in the five patients was 85, 85, 50, 59, and greater than 40 mm Hg, resulting in CPPs of 25, 3, 25, 56, and less than 50 mm Hg, respectively. Removing the bone flap as well as opening the dura and removing the blood clot produced a significant decrease in ICP and an increase in CPP. Jugular venous oxygen saturation (SjvO2) increased in four patients and decreased in the other during removal of the hematoma. Laser Doppler flow also increased, to 217% and 211% compared with preevacuation flow. CONCLUSIONS: Intracranial pressure is higher than previously suspected and CPP is very low in patients with ASDH. Removal of the bone flap yielded a significant reduction in ICP, which was further decreased by opening the dura and evacuating the hematoma. The SjvO2 as well as laser Doppler flow increased in all patients but one immediately after removal of the hematoma.
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OBJECT: Oxygen supply to the brain is often insufficient after traumatic brain injury (TBI), and this results in decreased energy production (adenosine triphosphate [ATP]) with consequent neuronal cell death. It is obviously important to restore oxygen delivery after TBI; however, increasing oxygen delivery alone may not improve ATP production if the patient's mitochondria (the source of ATP) are impaired. Traumatic brain injury has been shown to impair mitochondrial function in animals; however, no human studies have been previously reported. METHODS: Using tissue fractionation procedures, living mitochondria derived from therapeutically removed brain tissue were analyzed in 16 patients with head injury (Glasgow Coma Scale Scores 3-14) and two patients without head injury. Results revealed that in head-injured patients mitochondrial function was impaired, with subsequent decreased ATP production. CONCLUSIONS: Decreased oxygen metabolism due to mitochondrial dysfunction must be taken into account when clinically defining ischemia and interpreting oxygen measurements such as jugular venous oxygen saturation, arteriovenous difference in oxygen content, direct tissue oxygen tension, and cerebral blood oxygen content determined using near-infrared spectroscopy. Restoring mitochondrial function might be as important as maintaining oxygen delivery.
OBJECT: Determining the efficacy of a drug used in experimental traumatic brain injury (TBI) requires the use of one or more outcome measures such as decreased mortality or fewer neurological and neuropsychological deficits. Unfortunately, outcomes in these test batteries have a fairly large variability, requiring relatively large sample sizes, and administration of the tests themselves is also very time consuming. The authors previously demonstrated that experimental TBI and human TBI induce mitochondrial dysfunction. Because mitochondrial dysfunction is easy to assess compared with neurobehavioral endpoints, it might prove useful as an outcome measure to establish therapeutic time windows and dose-response curves in preclinical drug testing. This idea was tested in a model of TBI in rats. METHODS: Animals treated with the selective N-type voltage-sensitive calcium channel blocker Ziconotide (also known as SNX-111 and CI-1009) after cortical impact displayed significant improvement in brain mitochondrial function. When a single intravenous bolus injection of 4 mg/kg Ziconotide was given at different time intervals, ranging from 15 minutes before injury to 10 hours after injury, mitochondrial function was improved at all time points, but more so between 2 and 6 hours postinjury. The authors evaluated the effects on mitochondrial function of Ziconotide at different doses by administering 0.5 to 6 mg/kg as a single bolus injection 4 hours after injury, and found 4 mg/kg to be the optimum dose. CONCLUSIONS: The authors established these time-window profiles and dose-response curves on the basis of mitochondrial outcome measures in a total of 42 rats because there were such low standard deviations in these tests. Establishing similar time-window profiles and dose-response curves by using neurobehavioral endpoints would have required using 114 rats in much more elaborate experiments.
The objective of this study is to determine characteristic magnetic resonance imaging (MRI) features of intracranial plasmocytic granulomas. Pathological confirmation of three patients with intracranial pathologically confirmed plasmocytic granuloma are presented. Clinical records as well pre- and postgadolinium-enhanced images from each patient are reviewed. The location of the abnormalities is compared with previous reported cases of plasmocytic granulomas, to determine if there is a characteristic finding in this disense. The predominance of this abnormality in the pediatric and young adult patient was striking. On T(1)-weighted MRI, plasmocytic granulomas appear as hypointense lesions, with isointense appearance on T(2) images, and significant, variable patterns of enhancement after the infusion of gadolinium. Typically, the lesion is infiltrating, and causes little mass effect. A dural based lesion, as well as a sellar region abnormality and an infiltrating cortical lesion with little mass effect in the pediatric or young adult age group may lead the observer to suspect the diagnosis of plasmocytic granuloma.
Aspergillus species are uncommon etiologic agents of vertebral osteomyelitis. We describe two patients with lumbar vertebral aspergillosis precipitated by the use of corticosteroids and review 39 cases in the literature. The mean age of the population was 40.04 years. There was male predominance (78% of cases), mainly lumbar involvement (53.7%), and monomicrobial nature of infection; 65.8% of the patients had predisposing factors, while 34.1% had none. Back pain (53.6% of cases) was the predominant symptom, while neurological deficits were present in 29.2% of the patients. White blood cell counts were elevated in 12.2% of the patients, and erythrocyte sedimentation rates were >40 mm/h in 39%. The overall recovery rate was 68.3%, and the mortality rate was 26.8%. Although aspergillus osteomyelitis is primarily treated medically, certain cases may require surgical intervention.
The temperature distribution produced in living brain tissue by a radiofrequency, Neuro N-50, hyperthermia probe was measured as a function of probe temperature, heating duration, and distance from the heating probe by a sensor containing five thermocouples for durations up to 2 min. Brain sections were examined to determine the effects of heating at various temperatures. It was found that a simple theoretical conductive heat transfer model predicted the steady-state temperature distributions quite well. At distances up to 7.4 mm from the heating probe, a heating time of 20 s was sufficient to produce about 90% of the temperature rise measured at 120 s. The equilibrium temperature at any distance from the center of the probe was a linear function of the reciprocal of this distance. The time constant for heating was approximately 3 s at 0. 95 mm from the heating probe and about 10 s at 7.4 mm for brain tissue, while these values are about 5-20 s in egg white. For a given probe size, higher probe temperatures increased the size of the region of cell death. According to the heat transfer model, the diameter of the region of tissue that attains a given temperature is proportional to the diameter of the probe. The use of probe temperatures up to 90 degrees C would enable an increase in the volume of the region of cell death, or the use of a smaller diameter probe to produce a lesion of a given size.
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The anatomical foundations for the endoscopic fenestration of the septum pellucidum have not been presented previously in an isolated fashion. Using a surgical microscope, the microsurgical anatomy of the septum pellucidum, lateral ventricles, and surrounding structures was examined in ten adult brains injected with silicone rubber. The mean anteroposterior length of the septum pellucidum was 41 mm (range 40-42). Its mean height was 13.11 mm (range 12-15) at the level of the foramen of Monro; 10 mm (range 9-11) at the frontal horns, and 8 mm (range 7-10) at the ventricular atrium. One to three septal veins delimited 2 or 3 avascular areas in the septum pellucidum. We found an anterior area which was consistently avascular and large enough to be fenestrated safety. More posterior areas, while avascular, were inconsistent in their size and shape.
Anterior decompressive procedures for the treatment of vertebral tumors have become increasingly popular in an attempt to improve the quality of life, relieve pain, and preserve or restore neurologic function. However, these procedures carry a significant rate of complications including hardware failure, due in part to technical factors. A computer-assisted system allowing for precise preoperative planning and real-time intraoperative interactive image localization has been implemented for spine instrumentation to optimize anterior instrumental fixation. We discuss our initial clinical experience and application to anterior vertebrectomy, and vertebral reconstruction with anterior instrumental fixation. We believe that computer-assisted spine surgery using infrared-based technology offers the necessary elements to make its use fast, reliable, and intuitive, providing an accurate and safe approach for optimization of spine surgery.
We recently demonstrated that posttraumatic administration of the N-type calcium channel blocker SNX-111 (S) and a novel blood-brain barrier penetrating antioxidant U-101033E (U), significantly alleviated mitochondrial dysfunction induced by traumatic brain injury (TBI) in rats. The present study was designed to determine whether a combination of S and U, which act on different biochemical mechanisms of secondary brain injury, would be more efficacious than either drug alone. Brain mitochondria from injured and uninjured hemispheres were isolated and examined at 12 h post TBI induced by a severe controlled cortical impact injury. S at 1.0 mg/kg significantly increased both State 3 and 4 rates and produced a slight increase in P/O ratio, and there was virtually no change in RCI. U at 1.0 mg/kg did not show any protection. However, the combined treatment of S at 1.0 mg/kg and U at 1.0 mg/kg eliminated the uncoupling effect of S, and restored not only State 3 rates and P/O ratios but also RCI to near sham values. These results provide further evidence that both reactive oxygen species and perturbation of cellular calcium homeostasis participate in the pathogenesis of TBI-induced mitochondrial dysfunction, and support the idea of using combined therapy with lower drug doses.
BACKGROUND AND PURPOSE: Small case series have reported potential benefit from thrombolysis after spontaneous intraventricular hemorrhage (IVH). Our objective was to review our experience using intraventricular urokinase (UK) in treating selected patients with IVH. METHODS: Using medical records, we identified all patients who received ventriculostomies for CT-confirmed nonaneurysmal nontraumatic spontaneous IVH from December 1992 through November 1996. We reviewed charts and CT images and examined the data for associations with specific outcomes. RESULTS: We identified 40 patients, 18 treated with ventriculostomy alone and 22 receiving adjunctive intraventricular UK. The initial Glasgow Coma Scale (GCS) scores of the two groups were similar (P = 0.5). While there was a trend for patients with any intraparenchymal hemorrhage (IPH) to receive UK (P = 0.07), the mean size of IPH in those who received ventriculostomy alone was larger than in those who received adjunctive UK (P = 0.002). There was lower mortality in the group treated with UK (31.8 versus 66.7%; P = 0.03), but there was only a trend toward an increase in favorable outcome (22.2% versus 36.4%; P = 0.3). Overall, the most significant association with outcome was neurological condition at presentation (GCS >5 versus < or = 5; P = 0.003). Receiving UK did not increase the occurrence of complications or hospital length of stay for survivors (P = 0.5). CONCLUSIONS: Intraventricular UK remains a safe and potentially beneficial intervention. While it appeared to lower mortality, a randomized, placebo-controlled trial is needed to explore whether the therapy can increase the incidence of favorable outcomes.