W. S. Poon

Flow diverters for treatment of intracranial aneurysms: current status and ongoing clinical trials.

The ultimate treatment goal for intracranial aneurysms is to reconstruct the vessel wall and correct the hemodynamic disturbance. A flow diverter is a stent placed in the parent artery to reduce blood flow in the aneurysm sac to the point of stagnation, gradual thrombosis, and neointimal remodeling to maintain outflow in the side branches and perforators. Here, we review the two commercially available flow diverters, the Pipeline Embolization Device (PED) and the SILK flow diverter (SFD). The rates of severe hemorrhagic complications have been reported to be 2% for the PED and 0.8% for the SFD. The results of studies completed thus far show that endovascular reconstruction with flow diverters is an effective treatment of wide-necked, fusiform, large, and giant unruptured intracranial aneurysms, with 5% to 10% of patients experiencing permanent major morbidity and mortality. The results of ongoing studies may resolve whether flow diverters can replace coil embolization for the treatment of all, or selected, intracranial aneurysms.

CSF Antibiotic Prophylaxis for Neurosurgical Patients with Ventriculostomy: a Randomised Study

The value of prophylactic antibiotics for patients with ventricular catheter for monitoring and CSF drainage is uncertain. 228 patients were randomised to receive perioperative antibiotics only (Unasyn, Group I) or prolonged antibiotics for the presence of the ventricular catheter (Unasyn and Aztreonam, Group II). The incidence of intracranial and extracranial infection was documented prospectively. Group II patients had a significantly reduced incidence of CSF infection [3/115 (3%) vs 12/113 (11%), p = 0.01] and extracranial infections [23/115 (20%) vs 48/113 (42%), p = 0.002]. CSF pathogens in Group II patients were MRSA and Candida, whereas in Group I, Staphylococci, E coli and Klebsiella. Although prolonged antibiotic prophylaxis significantly reduced the incidence of serious CSF infection as well as extracranial infections, this policy did select resistant or opportunistic pathogens such as Candida and MRSA.

The pathological spectrum of diffuse axonal injury in blunt head trauma: assessment with axon and myelin stains

Although diffuse axonal injury (DAI) has been described as a major form of primary damage to the brain in blunt head injury, there has been no systematic study of the pathological changes in different regions of the brain. In this study, 22 cases of DAI were comprehensively examined histologically in the following areas: corpus callosum, internal capsule, superior cerebellar peduncles, cerebral white matter, fornix, rostral brain stem and globus pallidus, with a total of 17 standard blocks in each case. Sections were stained for axons with Glees and Marsland and neurofilament immunostaining and myelin with luxol fast blue and myelin basic protein immunostaining, and axonal retraction balls and myelin globoids were counted. Neurofilament immunostaining was superior to Glees and Marsland in both the positivity rates and the actual scores. Small myelin globoids were identified by the myelin stains, probably as a form of myelin damage secondary to axonal disruption. Such acute myelin damage was previously undescribed. There was no significant difference in both positivity rates and the scores obtained for luxol fast blue and myelin basic protein. Of all the regions of the brain examined, the internal capsule, corpus callosum and superior cerebellar peduncles yielded the highest counts of axonal balls as well as the highest incidences. It is recommended that in cases of DAI, these three regions of the brain should be examined most profitably with neurofilament immunostaining supplemented with a myelin stain.

Non-surgical primary treatment of chronic subdural haematoma: Preliminary results of using dexamethasone

From a series of 112 cases (64 men and 48 women, aged 37 – 91 years) of chronic subdural haematoma (CSDH) in a 2-year period from January 1998 to December 1999, we have prospectively studied a group of 30 patients, who were managed non-operatively: 26 patients were treated with dexamethasone (Group 1) and four patients expectantly (Group 4). Nineteen patients (73%) from Group 1 were confused or had focal neurological deficits on admission. The mean maximum thickness of the CSDH was 12 mm. Only one of these cases (4%) required surgical drainage 6 weeks after steroid therapy. One patient died of an unrelated stroke (mortality = 4%). Two patients (8%) were left severely disabled. No significant complication from steroid therapy was documented. Out of the 85 surgically treated patients, 69 patients underwent surgical drainage in addition to steroid therapy (Group 2). Thirteen patients were treated with burr-hole drainage only (Group 3). The mean maximum thickness of the CSDH for these two groups were both 16 mm. Comparing with group 1, the redrainage rate of Group 2 [4% (3/69, p = 1)] and that of Group 3 [15% (2/13, p = 0.253)] were not significantly different. 50% of patients in Group 4 (2/4, p = 0.039) required delayed surgical drainage. The mortality rates of Groups 2, 3 and 4 were 3% (2/69, p = 1), 15% (2/13, p = 0.253) and 50% (2/4, p = 0.039), respectively. Our results suggest that steroid treatment in a selected group of patients is a good option, particularly in patients with co-morbidity.

Comparison of management outcome of primary and secondary referred patients with traumatic extradural haematoma in a neurosurgical unit

A total of 104 patients with a traumatic extradural haematoma in a 5-year period were studied. The mortality of the 71 patients managed primarily by the neurosurgical unit was less than that of the 33 patients secondarily transferred from the district general hospital: 4 per cent vs 24 per cent. This better result was associated with a shorter delay between the time of conscious level deterioration and decompressive operation: 0.7 +/- 1.0 h vs 3.2 +/- 0.5 h. Direct admission of all head injured patients to a neurosurgical unit resulted in significant reduction in mortality and morbidity in patients with an extradural haematoma.

Clipping vs coiling of posterior communicating artery aneurysms with third nerve palsy

The authors investigated the evolution of third nerve palsy in patients with posterior communicating artery aneurysms who underwent coiling vs clipping. There was no statistical difference of complete third nerve palsy recovery in both treatments. Both techniques were of clinical benefit. Older age, diabetes, delayed interventions, and complete third nerve palsy at presentation indicated a poor prognosis for recovery.

The surgical treatment of intracranial aneurysms based on computer Tomographic angiography alone – streamlining the acute mananagement of symptomatic aneurysms

Summary. Background: We aimed to prospectively assess the usefulness of computer tomographic angiography (CTA) in streamlining the management of symptomatic intracranial aneurysms in a tertiary neurosurgical unit, from admission to surgery. Methods: We performed a prospective evaluation over a 2-year period of all symptomatic intracranial aneurysms managed according to a standardized departmental protocol, to assess how CTA has impacted the decision-making process pertaining to the suitability of this investigation to proceed directly to surgery. Findings: A total of 90 patients with intracranial aneurysms were treated over the 2-year period. 23 (26%) underwent endovascular occlusion while 67 (74%) patients underwent a surgical clipping procedure. In the surgical group, 22 (33%) patients had their aneurysms clipped based on CTA alone, while 45 (67%) required additional conventional angiography prior to surgery. Thus around one quarter of all patients treated for symptomatic intracranial aneurysms in our unit had their aneurysm secured surgically based solely on CTA. Interpretation: CTA significantly influences the acute management of symptomatic intracranial aneurysms by streamlining the decision-making process during the early and acute management of these lesions.

Evaluation of cognitive impairment by the Montreal Cognitive Assessment in patients with aneurysmal subarachnoid haemorrhage: prevalence, risk factors and correlations with 3 month outcomes

Objective Identification of patients with aneurysmal subarachnoid haemorrhage (aSAH) with cognitive impairment is important for patient management (medical treatment, cognitive rehabilitation and social arrangements). The Montreal Cognitive Assessment (MoCA) is currently recommended over the Mini-Mental State Examination (MMSE) by the US National Institute of Neurological Disorder, in the chronic post-stroke setting. We hypothesised that the MoCA has a better correlation with functional outcome at 3 months than the MMSE. Methods We carried out a prospective observational study in Hong Kong over a 2 year period, recruiting patients aged 21–75 years with aSAH admitted within 96 h of ictus. The assessments included the modified Rankin Scale, Lawton Instrumental Activity of Daily Living (IADL), Short Form-36, MoCA and MMSE at 3 months after ictus. Analyses were carried out to compare MoCA with MMSE. Results 90 patients completed the 3 month assessments. Cognitive impairment (MoCA <26) was determined in 73% of patients at 3 months. Delayed cerebral infarction explained the 31–38% variance in cognitive outcomes (MMSE and MoCA) at 3 months. MoCA demonstrated good discrimination of favourable neurological and IADL outcomes similar to the MMSE in receiver operating characteristics curve analyses. Conclusions MoCA defined cognitive impairment was common at 3 months after aSAH and MoCA correlated with functional outcomes similar, but not superior, to the MMSE. The study is registered at ClinicalTrials.gov of the US National Institutes of Health (NCT01038193).

Successful treatment of amoebic meningoencephalitis in a Chinese living in Hong Kong

Primary amoebic meningoencephalitis due to Naegleria fowleri was found in a 38-year-old Chinese man living in Hong Kong who presumably acquired the infection from swimming in a hot spring in neighbouring China. Amoebic cysts were identified in tissue taken from a brain abscess. The patient responded to surgical drainage and a 6-week course of amphotericin B, rifampicin and chloramphenicol. This is one of 6 cases of successful treatment of primary amoebic meningoencephalitis documented in the medical literature.

Cerebral venous oxygen saturation monitoring: is dominant jugular bulb cannulation good enough?

Venous oxygen saturation at the clinically dominant jugular bulb (SjO2) and that at the confluence of the cerebral sinuses (SccsO2) were compared by direct simultaneous blood sampling of 13 severely head injured patients. The side of dominant jugular bulb (JB) was determined by neck compression test. The right side was chosen if the test was equivocal. In effect, the right side was cannulated in all cases. Subsequent angiography showed that two of the 13 cases were left side dominant. In all, 176 pairs of blood samples were analysed. Correspondence rates (the difference between each pair of blood samples being less than 4% of oxygen saturation) for individual case were good (80-100%) in nine cases including one case with left side dominance. Correspondence rates were moderate in two cases (50 and 56%); the differences were not clinically significant. In the remaining two cases, including one with left side dominance, the correspondence rates were poor (0 and 4%, respectively); SccsO2 was always lower than SjO2; median differences were 13.4 and 23.1%. Ischemia in the cerebral hemispheres would have been underestimated if management were based on SjO2. Monitoring at the dominant JB accurately reflected the global and hemispheric cerebral oxygenation in 11/13 of cases. Monitoring at the non-dominant JB is not recommended.