A comparison of epidural levobupivacaine 0.5% with or without epinephrine for lumbar spine surgery.

Levobupivacaine, the S(-) isomer of bupivacaine, is less cardiotoxic than racemic bupivacaine. In this prospective, randomized, double-blinded study of epidural anesthesia, we compared the onset, extent, and duration of sensory and motor blockade produced by plain 0.5% levobupivacaine (15 mL, 75 mg) with that of 0.5% levobupivacaine with the addition of 1:400,000 or 1:200,000 epinephrine in 117 patients undergoing elective spine surgery. The time to onset of adequate sensory block (T10 dermatome) was similar in all groups (12.4 +/- 6.6 min for plain levobupivacaine, 13.9 +/- 7.9 min for levobupivacaine with 1:400,000 epinephrine, and 12.7 +/- 4.9 min for levobupivacaine with 1:200,000 epinephrine), with an average peak block height of T5. Time to complete regression of sensory blockade was also similar between groups (357 +/- 119 min for plain levobupivacaine, 378 +/- 98 min for levobupivacaine with 1:400,000 epinephrine, and 348 +/- 80 min for levobupivacaine with 1:200,000 epinephrine). Peak serum levobupivacaine levels were reduced in each of the epinephrine-containing groups. We conclude that 0.5% levobupivacaine with or without 1:200,000 or 1:400,000 epinephrine produced effective epidural anesthesia in patients having lumbar spine surgery. Epinephrine 1:400,000 is as effective as 1:200,000 in reducing the resultant serum levobupivacaine levels after epidural anesthesia.

The impact of acute hyponatraemia on severe traumatic brain injury in rats.

The effect of experimental acute hyponatraemia on severe traumatic brain injury (TBI) was studied in a modified impact-acceleration model. The cortical contusional volume was quantified by image analysis on serial sections, injured axons were visualized and quantified by beta-Amyloid Precursor Protein (beta-APP) immunohistochemical staining. Regional brain water content was estimated by the wet-dry weight method. The experiment was conducted in Group I (injury only) and Group II (injury followed by acute hyponatraemia). Comparison between the two groups showed that acute hyponatraemia significantly increased contusional volume (3.24 +/- 0.70 mm3 vs. 1.80 +/- 0.65 mm3, P = 0.009) and the number of injured axons (128.7 +/- 44.3 vs. 41.7 +/- 50.1, P = 0.04) in the right thalamus & basal ganglia region. Water content of the brain stem region was also significantly increased by acute hyponatraemia (73.71 +/- 0.14% vs. 72.28 +/- 0.93%, P = 0.004). These results suggest that acute hyponatraemia potentiates secondary brain damage in severe TBI by augmentation of both focal contusion and diffuse axonal injury. The injured brain stem region is more susceptible to edema formation induced by experimental acute hyponatraemia.

Intraventricular recombinant tissue plasminogen activator for treatment of spontaneous intraventricular haemorrhage in pregnancy.

Spontaneous intracranial haemorrhage during pregnancy, which is usually subarachnoid or intraparenchymal in nature, causes significant maternal and foetal morbidity and mortality. Solitary intraventricular haemorrhage (IVH) in pregnancy has never been previously reported nor has the use of intraventricular fibrinolysis in this situation. A 28-year-old woman presented at 20 weeks' gestation with status epilepticus from spontaneous severe IVH. Angiography and magnetic resonance imaging did not show the presence of a vascular lesion or aneurysm. Thrombolytic treatment with intraventricular injection of recombinant tissue plasminogen activator (rt-PA) was instituted. Although the foetus aborted spontaneously 6 weeks after the haemorrhage and a ventriculo-peritoneal shunt for hydrocephalus was eventually required, the mother recovered to the level of mild disability at 3 months. Intraventricular fibrinolysis with rt-PA seems to be an effective form of treatment for IVH in pregnancy.

Vagus nerve stimulation for seizure control: Local experience.

Vagus nerve stimulation (VNS) is a relatively new therapeutic approach for intractable epilepsy. Its safety and efficacy have already been documented by randomized clinical studies conducted in Europe and North America. To date, more than 800 vagus nerve stimulators have been implanted throughout the world. We report here our 6 cases of VNS in Chinese epileptic patients and present the results. The indications for this device, and also its associated problems, are also discussed.

Postconcussion syndrome following mild head injury: how significant when it is work-related?

Postconcussional complaints are common after mild head injury. These symptoms can be so severe that some patients are unable to return to their previous employment. The purpose of this study is to investigate how important is work-related injury as a factor in determining the degree of disability caused by postconcussional symptoms. We studied 67 patients suffering from postconcussion syndrome after a mild head injury. These patients were divided into two groups, work-related injury and non-work-related injury. The results of this study demonstrated that the median duration of sick leave and the median amount of compensation were significantly higher in the work-related group (8 months vs. 1 month, P = 0.0007; US$9000 vs. US$500, P = 0.0035, respectively). Only 41% of the work-related injured patients returned to work, compared with 85.7% in the nonwork-related injury group (P = 0.0022). The results of this study strongly suggested that work-related injury is a significant factor in determining the degree of disability associated with postconcussion syndrome.

High-risk mild head injury.

The generally accepted definition of mild head injury includes Glasgow Coma Scale (GCS) scores of 13 to 15. However, many studies have shown that there is a heterogeneous pathophysiology among patients with GCS scores in this range. The current definition of mild head injury is misleading because patients classified in this category can have severe sequelae. Therefore, a prospective study of 1360 head-injured patients with GCS scores ranging from 13 to 15 who were admitted to the neurosurgery service during 1994 and 1995 was undertaken to modify the current definition of mild head injury. Data regarding patients' age, sex, GCS score, radiographic findings, neurosurgical intervention, and 6-month outcome were collected and analyzed. The results of this study showed that patients with lower GCS scores tended to have suffered more serious injury. There was a statistically significant trend across GCS scores for percentage of patients with positive acute radiographic findings, percentage receiving neurosurgical interventions, and percentage with poor outcome. The presence of postinjury vomiting did not correlate with findings of acute radiographic abnormalities. Based on the results of this study, the authors divided all head-injured patients with GCS scores ranging from 13 to 15 into mild head injury and high-risk mild head injury groups. Mild head injury is defined as a GCS score of 15 without acute radiographic abnormalities, whereas high-risk mild head injury is defined as GCS scores of 13 or 14, or a GCS score of 15 with acute radiographic abnormalities. This more precise definition of mild head injury is simple to use and may help avoid the confusion caused by the current classification.

Monitoring of autoregulation using laser Doppler flowmetry in patients with head injury.

The authors studied 31 comatose head-injured patients to assess the clinical usefulness of laser Doppler flowmetry (LDF) in continuous autoregulation monitoring. The LDF probes were placed on the surface of the cerebral cortex. Data on LDF, intracranial pressure (ICP), and arterial blood pressure (ABP) were recorded and continuously entered into a computer. The data were broken down into multiple segments of 15 minutes' duration (epochs). Epochs showing rapid change in cerebral perfusion pressure (CPP), change in CPP of less than 10 mm Hg, LDF values of less than five arbitrary units, and loss of ABP/ICP waveform were excluded from further analysis. A linear relationship between LDF and CPP in individual epochs was used as an indicator of loss of autoregulation. The relationship between LDF and CPP changed with time, indicating improvement or deterioration in autoregulation. Longitudinal analysis of all the epochs measured in a patient revealed three patterns of progress: 1) intact autoregulation; 2) transient loss; and 3) persistent loss of autoregulation. All five patients with intact autoregulation had a good outcome. Ten patients experienced transient loss of autoregulation; of these four had a good outcome, five were moderately disabled and one was severely disabled. Transient impairment of autoregulation did not always indicate poor outcome, provided the impaired autoregulation responded to treatment. In 11 patients who had persistent loss of autoregulation, nine died and two were severely disabled. In five cases the LDF probe lost contact with the cerebral cortex and no useful information was obtained. Real-time measurement of autoregulation using LDF and CPP monitors was achieved and the findings were related to outcome in these patients.

The time course and regional variations of lipid peroxidation after diffuse brain injury in rats.

Free radicals are generated after head injury. These radicals rapidly react with polyunsaturated fatty acids in the cell membrane and cause membrane destruction. This process is called lipid peroxidation. Malondialdehyde (MDA) is one of the end products of lipid peroxidation, and it is a frequently used indicator of lipid peroxidation in biological tissues. Using a diffuse head injury animal model, we studied the time course of lipid peroxidation in different regions of injured rat brains. In the present study, the MDA levels were 36.7%, 41.8%, and 35.1% greater than sham at one hour after injury at the frontal, parietal, and brain stem, respectively (p < 0.0001). The MDA levels in these regions continued to increase and peaked a 4 hours after the injury. The levels slowly decreased, and by 24 hours, they were still significantly higher than the sham control's. The elevation of MDA levels was less in the striatum and the temporal regions at one hour. They were 16.9% and 13.3%, respectively (p < 0.002). The MDA levels in these two regions continued to increase even after 4 hours of injury, but the degree of elevation never exceeded 35%. The results demonstrate that there is an immediate, posttraumatic burst of MDA production, suggesting the formation of free radicals after diffuse head injury. Even though all the regions sampled show the same effect, certain regions are less affected by this diffuse head injury animal model.

Putaminal and thalamic hemorrhage in ethnic chinese living in Hong Kong.

BACKGROUND: Hemorrhagic stroke is very common in the Chinese population, and it is one of the leading causes of mortality in Chinese communities. The risk factors to explain this high incidence are unknown. It is the purpose of this study to look into the features of hemorrhagic stroke in the Hong Kong Chinese. METHODS: We conducted a prospective hospital-based study in which 60 consecutive Chinese patients with computed tomography diagnosis of putaminal or thalamic hemorrhage were included. Their demographic and clinical data were collected and analyzed. RESULTS: Two major findings evolved from the present study. (1) Unlike the Western studies, the majority of our patients were about a decade younger; (2) 50% of the patients had previously diagnosed hypertension, but only 20% of these patients were compliant with their antihypertensive medication. Our results also suggested that low admission Glasgow Coma Scale scores, large hematoma size, and the presence of intraventricular blood were associated with poor outcomes. CONCLUSIONS: This study concludes that hemorrhagic stroke is indeed a serious health problem in Hong Kong. Simple measures, such as improvement of health education and the primary care system in the management of hypertension, would help to reduce the incidence of hemorrhagic stroke.

Atypical monoclonal plasma cell hyperplasia: its identity and treatment. Case report.

Atypical monoclonal plasma cell hyperplasia, like plasma cell granuloma, is an inflammatory pseudotumor. Both are extremely rare in the central nervous system. Atypical monoclonal plasma cell hyperplasia is a recently identified neuropathological entity described by Weidenheim, et al., in 1989. A second case of this disease entity is now reported. The histological findings that differentiate this lesion from plasma cell granuloma, plasmacytoma, and meningioma are discussed. The present case clearly demonstrates the complete resolution of the disease after a course of fractionated radiotherapy.

Features of pediatric head injury in Hong Kong.

Head injury in children causes special concern in most communities. From 1989 to 1994, 2,785 children younger than 16 years old were admitted to our neurosurgical service because of head injury. Fall from a height was the major cause of head injury leading to admission in infants and children in preschool age groups, whereas traffic-related or bicycle-related accidents were more likely to be the cause of head injury for those aged 11-15 years. In all age groups there was a male preponderance. The overall mortality was 0.6%. Traffic-related accidents caused more severe injury and accounted for 67% of all fatalities. For patients under 6 years old, about 40% of head injuries occurred at home. Preventive measures for pediatric head injury in Hong Kong are suggested.

Dural cavernous angiomas in a child.

Dural-based cavernous angiomas are rare intracranial vascular lesions. Most of the reported cases are located in the middle cranial fossa, and those located outside the middle fossa are even more uncommon. Thus far, only 3 pediatric cases have been reported and all of them were found outside the middle fossa of a neonate. We would like to add the fourth pediatric case of a dural-based cavernous angioma located in the posterior fossa of a 5-year-old boy.

The role of computed tomographic angiography in the diagnosis of intracranial aneurysms and emergent aneurysm clipping.

Conventional cerebral angiography has always been regarded as the gold standard for intracranial aneurysm detection. However, conventional angiography has the disadvantages of being invasive and time consuming. We present here 30 patients who underwent computed tomographic angiography (CTA) with three-dimensional reconstruction for the detection of intracranial aneurysms. All of these patients had subarachnoid hemorrhage or suspected intracranial aneurysms. CTA was performed in all patients with the use of a General Electric Hispeed Advantage helical scanner. Iohexol, 135 ml, was used as the contrast agent. Twenty-five patients also underwent conventional angiography for comparison. The five patients who underwent CTA only did not have conventional angiography because of poor clinical condition, and four of them subsequently died. Five patients had subarachnoid hemorrhage, but the results of both CTA and conventional angiography were negative for aneurysms. One patient had an incidental finding of a 3-mm left posterior communicating artery aneurysm on CTA, which was confirmed by conventional angiography. In the remaining 19 patients, 19 saccular aneurysms and 1 fusiform aneurysm were detected by CTA. Locations and sizes were confirmed by conventional angiography in all except two. The first exception was a patient who had a 2.5-mm anterior communicating artery aneurysm detected by CTA but not by conventional angiography. Surgical exploration confirmed the CTA diagnosis. The other exception was a patient in whom a 2-mm right posterior communicating artery aneurysm was detected by CTA but in whom conventional angiography showed a 2-mm left posterior communicating artery aneurysm. Unfortunately, there was no surgical confirmation in this case because the family of the patient refused surgery. Our results have demonstrated that CTA is a quick, reliable, and relatively simple diagnostic tool for intracranial aneurysms. In an emergent situation, such as a deteriorating patient with a hematoma, it is superior to either empiric exploration or infusion computed tomographic scans because it delineates the orientation and configuration of the aneurysm and its associated vascular anatomy.