The risk of rebleeding after external lumbar drainage in patients with untreated ruptured cerebral aneurysms

BACKGROUND

Does continuous external lumbar CSF drainage before aneurysm repair in patients with aneurysmal subarachnoid hemorrhage increase the risk of rebleeding?

METHOD

The study population, consisting of 18 patients treated by External Lumbar Drainage (ELD) after SAH before aneurysm repair, was compared with an independent control group of 324 SAH patients treated in another clinic. Control patients were selected for not being treated for the ruptured aneurysm yet and not having undergone any form of CSF drainage during the exposure time in the case patients. We calculated hazard ratios with the Cox regression model, adjusted for age and clinical condition on admission and hydrocephalus.

FINDINGS

The cox regression analysis shows a non-adjusted hazard ratio of 2.1 (95% CI 0.8 to 5.3) in the model with 5 rebleedings in 18 patients. Adjustment for age, clinical condition on admission and hydrocephalus did not alter the hazard ratio estimate importantly in either analyses.

CONCLUSIONS

An increased risk of rebleeding by external lumbar drainage in the acute phase after aneurysmal SAH could not be confirmed, but the data are too imprecise to rule out an increased risk. The potential benefits of early drainage should be weighed against the risks if the aneurysm is not occluded before or early after the start of drainage.

Timing of aneurysm surgery in subarachnoid haemorrhage--an observational study in The Netherlands

BACKGROUND

There is still lack of evidence on the optimal timing of surgery in patients with aneurysmal subarachnoid haemorrhage. Only one randomised clinical trial has been done, which showed no difference between early and late surgery. Other studies were observational in nature and most had methodological drawbacks that preclude clinically meaningful conclusions. We performed a retrospective observational study on the timing of aneurysm surgery in The Netherlands over a two-year period.

METHOD

In eight hospitals we identified 1,500 patients with an aneurysmal subarachnoid haemorrhage. They were subjected to predefined inclusion criteria. We included all patients who were admitted and were conscious at any one time between admission and the end of the third day after the haemorrhage. We categorised the clinical condition on admission according the World Federation of Neurological Surgeons (WFNS) grading scale. Early aneurysm surgery was defined as operation performed within three days after onset of subarachnoid haemorrhage; intermediate surgery as performed on days four to seven, and late surgery as performed after day seven. Outcome was classified as the proportion of patients with poor outcome (death or dependent) two to four months after onset of subarachnoid haemorrhage. We calculated crude odds ratios with late surgery as reference. We distinguished between management results (reconstructed intention to treat analysis) and surgical results (on treatment analysis). The results were adjusted for the major prognosticators for outcome after subarachnoid haemorrhage.

FINDINGS

We included 411 patients. There were 276 patients in the early surgery group, 36 in the intermediate surgery group and 99 in the late surgery group. On admission 78% were in good neurological condition (WFNS I-III). MANAGEMENT RESULTS: Overall, 93 patients (34%) operated on early had a poor outcome, 13 (36%) of those with intermediate surgery and 37 (37%) in the late surgery group had a poor outcome. For patients in good clinical condition on admission and planned for early surgery the adjusted odds ratio (OR) was 1.3 (95% CI 0.5 to 3.0). The adjusted OR for patients admitted in poor neurologicalcondition (WFNS IV-V) and planned for early surgery was 0.1 (95% CI 0.0 to 0.6). SURGICAL RESULTS: For patients in good clinical condition on admission who underwent early operation the adjusted OR was 1.1 (95% CI 0.4 to 3.2); it was 0.2 (95% CI 0.0 to 0.9) for patients admitted in poor clinical condition.

CONCLUSIONS

In this observational study we found no significant difference in outcome between early and late operation for patients in good clinical condition on admission. For patients in poor clinical condition on admission outcome was significantly better after early surgery. The optimal timing of surgery is not yet settled. Ideally, evidence on this issue should come from a randomised clinical trial. However, such a trial or even a prospective study are unlikely to be ever performed because of the rapid development of endovascular coiling.

Cerebral microdialysis and positron emission tomography after surgery for aneurysmal subarachnoid hemorrhage in grade I patients

BACKGROUND

Using cerebral microdialysis, baseline values for energy-related chemical markers have been reported in awake patients. Radionuclide studies have demonstrated a locally decreased metabolism, thought to be the result of brain retraction. These baseline values, however, may not be applicable to patients after surgical aneurysm repair following a subarachnoid hemorrhage (SAH). We assessed metabolic chemical marker levels in World Federation of Neurological Surgeons Committee (WFNS) grade I SAH patients after aneurysm surgery and compared them with previously reported baseline values.

METHODS

In 5 WFNS grade I SAH patients, energy-related chemical marker levels were obtained using microdialysis in the area of brain retraction after aneurysm surgery. In addition, an [(18)F]2-deoxy-d-glucose positron emission tomography (FDG-PET) was performed.

RESULTS

The FDG-PET showed a decrease of glucose metabolism in the frontotemporal area. Comparing the mean values for chemical markers of this study with reported baseline values, the most striking difference was a mild decrease of pyruvate and an increase of the lactate/pyruvate ratio. In individual patients, some markers indicated possible ischemia. A consistent pattern or ischemic profile for all markers, however, was not found.

CONCLUSION

FDG-PET scanning confirmed postoperative metabolic changes found in previous studies. Mean interstitial chemical marker levels ranged from normal to mildly deviant compared with reference chemical marker levels for awake patients and are likely to be applicable in SAH patients after aneurysm repair.

Metastatic adenocarcinoma in the cerebellopontine angle, presenting as a meningioma: a case report of rare occurrence

We present the case of a 36-year old woman who was referred to our hospital with an 8 weeks history of walking difficulties, nausea and vomiting, diminished hearing on the right side and diplopia. On Magnetic Resonance-Imaging (MRI) a tumour in the right cerebellopontine angle (CPA) was diagnosed. The tumour was resected and histopathological examination revealed an adenocarcinoma, suspicious for a metastasis from carcinoma of the breast considering the aspect of the cells, immunochemical profile, age and gender of the patient. No primary tumour was found. In cases without histopathological diagnosis, radiosurgery should be withheld when there is doubt about the clinical or radiological diagnosis.

Craniopagus: the Suriname-Amsterdam conjunction

OBJECTS

A case of a Suriname female occipito-parietal to occipito-parieto-temporal craniopagus twins is described. The girls were transferred to the VU University Medical Center (VUmc) in Amsterdam, the Netherlands, for further diagnostics and to analyze whether surgical separation was feasible and ethically justifiable. The multifactorial aspects of different treatment options are discussed.

METHODS

The twins underwent multiple investigations by a multidisciplinary team. Advanced imaging techniques with 3D-CT scan, MRI and MRA scans, image fusion techniques and, most importantly, cerebral angiography with balloon occlusion tests were performed.

CONCLUSIONS

Because of a shared venous ring, with preferential drainage to the left child, and which endovascular balloon occlusion showed could not be separated, surgical separation of the twins with a fair chance of survival without additional neurological damage and with prospects of a good quality of life was regarded as impossible. In accordance with the parents' wishes, the twins were not separated and offered optimal integral conservative treatment.

The influence of brain tumor treatment on pathological delta activity in MEG

The goal of the MEG study was to investigate the influence of tumor treatment on pathological delta activity (1-4 Hz). The treatment consisted of neurosurgery, and in some of the patients, additional radiotherapy. MEG and MR recordings were made both before and after the treatment in 17 patients. The signal power in the delta frequency band was determined for each recording. The malignant tumors were associated with large tumor volumes. Furthermore, both malignant tumors and tumor volume were associated with high signal powers in the delta band, indicating a correlation of delta power with the severity of the lesions. In all patients with high grade tumors, the delta power was lower after the treatment. The sources underlying the delta signals were estimated with an automatic single dipole analysis method. Estimated sources were projected onto MR scans. Preoperatively 14 clusters of equivalent sources describing focal activity were found in 12 out of 17 patients. Thirteen of these clusters were located near the tumor, and one cluster near an edema border. The locations near tumors are plausible and suggest that in general the source estimation was reliable. After the operation, 13 such clusters were found in 12 patients. Eleven clusters were located near the lesion border and one cluster near the edema border. Furthermore a cluster contralateral to the lesion in the other hemisphere indicated that brain lesions can affect the functioning of more distant brain areas than just the peritumoral brain tissue. Of the 12 patients who had preoperatively peritumoral clusters, 11 patients had postoperatively perilesional sources. In these cases the shift in source locations was in general considerably smaller than the dimension of the preoperative tumors. This finding indicates that similar areas generate the pre- and postoperative delta activity. Furthermore, focal delta sources were found in a case without tumor recurrence, and also in cases that most tumor tissue was removed. These findings suggest that the pathology underlying the slow waves is not the presence of the tumor bulk but the structural damage done by the tumors on the surrounding white/gray matter.

The prognostic value of cognitive functioning in the survival of patients with high-grade glioma

The authors studied cognitive functioning as a potential predictor of survival in 68 newly diagnosed patients with high-grade glioma. In a combined Cox proportional hazards model, the influence of tumor, treatment, and patient characteristics, including cognitive functioning, was studied. Older age and higher tumor grade were associated with poorer survival. Although cognitive impairment was not found to be an independent prognostic factor for the entire sample, it was associated with significantly poorer survival among older patients with World Health Organization grade IV gliomas. Assessment of cognitive functioning in these patients may improve clinical decision making and thus quality of treatment.

Single-fraction vs. fractionated linac-based stereotactic radiosurgery for vestibular schwannoma: a single-institution study

PURPOSE

In this single-institution trial, we investigated whether fractionated stereotactic radiation therapy is superior to single-fraction linac-based radiosurgery with respect to treatment-related toxicity and local control in patients with vestibular schwannoma.

METHODS AND MATERIALS

All 129 vestibular schwannoma patients treated between 1992 and June 2000 at our linac-based radiosurgery facility were analyzed with respect to treatment schedule. Dentate patients were prospectively selected for a fractionated schedule of 5 x 4 Gy and later on 5 x 5 Gy at the 80% isodose in 1 week with a relocatable stereotactic frame. Edentate patients were prospectively selected for a nonfractionated treatment of 1 x 10 Gy and later on 1 x 12.5 Gy at 80% isodose with an invasive stereotactic frame. Both MRI and CT scans were made in all 129 patients within 1 week before treatment. All patients were followed yearly with MRI and physical examination.

RESULTS

A fractionated schedule was given to 80 patients and a single fraction to 49 patients. Mean follow-up time was 33 months (range: 12-107 months). There was no statistically significant difference between the single-fraction group and the fractionated group with respect to mean tumor diameter (2.6 vs. 2.5 cm) or mean follow-up time (both 33 months). Only mean age (63 years vs. 49 years) was statistically significantly different (p = 0.001). Outcome differences between the single-fraction treatment group and the fractionated treatment group with respect to 5-year local control probability (100% vs. 94%), 5-year facial nerve preservation probability (93% vs. 97%), and 5-year hearing preservation probability (75% vs. 61%) were not statistically significant. The difference in 5-year trigeminal nerve preservation (92% vs. 98%) reached statistical significance (p = 0.048).

CONCLUSION

Linac-based single-fraction radiosurgery seems to be as good as linac-based fractionated stereotactic radiation therapy in vestibular schwannoma patients, except for a small difference in trigeminal nerve preservation rate in favor of a fractionated schedule.

Long-term outcome of neurosurgical untethering on neurosegmental motor and ambulation levels

The aim of this study was to determine the long-term outcome of neurosurgical untethering on neurosegmental motor level and ambulation level in children with tethered spinal cord syndrome. Forty-four children were operated on (17 males, 27 females; mean age at operation 6 years 2 months, SD 5 years). Sixteen patients had myelomeningocele, nine had lipomyelomeningocele, and 19 had other types of spinal dysraphism. Motor level and ambulation level were assessed pre- and three times postsurgery (mean duration of follow-up 7 years 1 month, SD 1 year 8 months). Deterioration of motor level was seen in five of 44 patients, 36 of 44 remained stable, while improvement was seen in three of 44 patients. Deterioration of ambulation level was seen in five of 44 patients, and remained stable in 26 of 44. Thirteen of 44 children were too young to ambulate at time of operation (< 2 years 6 months). Late deterioration of motor or ambulation level was only seen in (lipo) myelomeningocele patients. Deterioration of ambulatory status was strongly associated with obesity and retethering. Revision of the initial tethered cord release was performed in nine of 44 patients, mainly in those with lipomyelomeningocele.

[Neuromonitoring of patients following severe brain trauma]

To a considerable extent, the neurological outcome of patients with severe brain trauma is determined by the primary injury caused by the accident. Substantial progress has been made in our understanding of the pathophysiological processes resulting in secondary brain damage after brain trauma, partly as a result of the introduction of advanced techniques of neuromonitoring. Early recognition and treatment of the symptoms leading to this type of brain damage seems crucial to the effort to improve the neurological outcome in these patients. Useful modern neuromonitoring techniques include: measurement of the intracranial and cerebral perfusion pressure and continuous electroencephalography. Methods that are also reliable and readily applicable, but less relevant clinically, include cerebral microdialysis of fluid from the extracellular space, determination of the parenchymal oxygen tension, and determination of the venous oxygen saturation. Other techniques that are not clinically applicable include: determination of the cerebral blood flow, the cortical tissue perfusion or the regional cerebral oxygenation.

Treatment of ruptured intracranial aneurysms: implications of the ISAT on clipping versus coiling

Patients with a ruptured intracranial aneurysm should be treated as soon as possible after the haemorrhage to prevent rebleeding and to allow vigorous treatment of ischemic events in case of vasospasm. The choice of treatment, endovascular or surgical, should be based on the angio-architectural aspects of the aneurysm. 3D rotational subtraction angiography will more clearly show the aneurysm morphology and will therefore help in the decision-making process. If an aneurysm is suitable for endovascular treatment ('coiling'), this should be the treatment of first choice, as has been clarified in the ISAT study. Location of the aneurysm only influences the treatment decision in aneurysms located at the basilar artery bifurcation. These aneurysms are preferably treated by endovascular means. The long-term results of endovascular and surgical treatment are still the subject of debate. For both treatment modalities, re-growth of the treated aneurysm has been described, but solid comparative data is missing. In analogy with the ISAT, referral of patients with a ruptured intracranial aneurysm should be performed as soon as possible after the haemorrhage. Preferably, this should be a hospital where neurosurgeons, interventional neuroradiologists, as well as neurologists (with expertise on medical treatment of patients with a subarachnoid haemorrhage) collaborate.

[Brain abscess: a difficult diagnosis]

A 40-year-old man had experienced headaches for 6 days and a 51-year-old man (2 weeks after an operation for perianal abscess) had experienced tingling sensations in the left hand for 10 days. After an epileptic seizure both underwent a CT scan of the brain. On these an abnormality was visible, probably a malignant astrocytoma. After several days of complaint reduction with dexamethasone, drowsiness and leftsided hemiparesis occurred. Emergency operations revealed a brain abscess. In the younger patient drainage and the administration of antibiotics were followed by fatal brain oedema. In the eldest drainage and the administration of antibiotics were followed by the extraction of infected teeth; he recovered with a slight loss of strength in the left hand. Brain abscesses are rare in the Netherlands. The diagnosis can be difficult because clinical signs and symptoms are not specific and because an underlying systemic infection is often not apparent. Diffusion-weighted magnetic resonance imaging can nowadays differentiate purulent brain processes from cystic brain tumors. Early treatment (burr hole aspiration and antibiotics) is usually curative. Nevertheless, mortality continues to be almost 10% and (permanent) morbidity 45%.

Increases in spinal fluid osmolarity induced by mannitol

OBJECTIVE

Mannitol is widely used in hospitals worldwide to treat patients with high intracranial pressure and/or cerebral edema. One of the mechanisms by which mannitol is thought to affect intracranial pressure is by increasing the patient's serum osmolarity, but not the osmolarity in the brain or cerebrospinal fluid. In this way, mannitol is thought to increase the osmolarity gap between the brain and the blood, which in turn leads to removal of excess water from the brain. However, relatively little is known regarding long-term effects of mannitol on osmolarity of cerebrospinal fluid. We therefore sought to determine the effects of mannitol administration on the osmolarity of cerebrospinal fluid.

DESIGN

Controlled trial.

SETTING

University teaching hospital.

PATIENTS

Patients with severe head injury and patients with subarachnoid bleeding who required insertion of an intracranial probe.

MEASUREMENTS AND MAIN RESULTS

Serum and cerebrospinal fluid osmolarity were measured before and during mannitol administration in ten patients treated with mannitol for >or=72 hrs (group 1), ten patients treated for 24 to 48 hrs (group 2), and ten controls (group 3). Serum osmolarity increased quickly in all patients receiving mannitol (groups 1 and 2), whereas remaining constant in controls. Average cerebrospinal fluid osmolarity slowly increased in all patients receiving mannitol; cerebrospinal fluid osmolarity increased from (mean +/- sd) 291.5 +/- 4.0 to 315.5 +/- 4.5 mOsm/kg after 96 hrs in group 1 (p <.01), and from 288.9 +/- 3.5 to 296.9 +/- 6.2 mOsm/kg after 48 hrs in group 2 (p <.01). Cerebrospinal fluid osmolarity remained constant in controls (p <.01 for group 1 vs. group 3 and for group 2 vs. group 3, respectively). In group 1, the gap between serum and cerebrospinal fluid osmolarity initially increased (which was the desired effect), but later decreased first to baseline values and then to below-normal levels.

CONCLUSIONS

Long-term administration of mannitol can induce significant increases in cerebrospinal fluid osmolarity in patients with subarachnoid hemorrhage or severe head injury. This may be an undesirable and potentially dangerous effect. Therefore, cerebrospinal fluid osmolarity should be measured regularly in all patients receiving mannitol for longer than 24 hrs. If cerebrospinal fluid osmolarity increases, discontinuation or tapering of mannitol therapy should be considered.

[Pain in the legs and progressive neurological deterioration: tethered cord syndrome in adults]

In four patients, women aged 58, 63 and 42 years, and a man aged 25 years, tethered cord syndrome was diagnosed. These patients suffered from progressive neurological symptoms, notably radiating pain in the legs in the first three patients, and muscle weakness and atrophy in the lower legs in the fourth patient. All four were treated surgically. Nowadays, the phrase tethered (spinal) cord is used for both occult and open closure defects of the neural tube. New neurological symptoms and signs can develop not only in childhood, but also in adults. Neurosurgical release of the tethered cord prevents further deterioration and often leads to significant subjective improvement of symptoms.

Oncolytic adenoviruses for treatment of brain tumours

Standard therapies are not capable of curing patients with malignant glioma; more than 90% of patients die within 2 years after diagnosis. Gene therapy appeared as a promising new approach for this disease. However, results of clinical trials with replication deficient viral vectors were disappointing. The main reasons being poor transduction efficiency of adenovirus towards glioma cells and limited spread and distribution of the vector in the tumour. With the increasing knowledge of viral genetics and its functions, an attractive alternative tool to kill malignant glioma cells has been developed: Replicating adenovirus as an oncolytic agent. This type of therapy, also referred to as virotherapy, has the potential to overcome some of the limitations connected with replication deficient adenoviral vectors. In this review the authors describe the latest developments in strategies that are being used to create a tumour- or glioma-selective replicating adenovirus. Special attention is given to the methods of viral delivery to an infiltrating tumour in the brain, regarding optimal dose and toxicity. Furthermore, the role of conventional antitumour treatments, such as irradiation and chemotherapy, in enhancing the effect of virotherapy is being emphasised.

[Aplasia cutis congenita in 4 infants]

In 4 infants, 3 boys and 1 girl, the congenital absence of skull skin was diagnosed: aplasia cutis congenita, a rare congenital skin defect, which usually presents as a solitary defect over the vertex of the skull measuring a few to approximately 10 centimetres. All four patients were treated with a skin transplantation and more than a year later the skin covered the skull well. There is no consensus concerning the treatment of aplasia cutis congenita. Due to unfamiliarity with this condition, a conservative approach is often adopted. The management strategy indicated should depend on the size of the defect and the child's physical condition. In the case of large defects, an early operative treatment is desirable to prevent serious complications such as haemorrhages and infections. Sufficient skin coverage can be obtained by using rotation scalp flaps, and if necessary additional split-skin grafts. In some patients large rotation flaps are not reliable due to the abnormal vascularity of the skin (Adams-Oliver syndrome). Split-skin grafting is the treatment of choice in these patients.

Trapped third ventricle

The authors report the case of a 29-year-old female who presented with symptoms of shunt dysfunction 11 years after first being shunted for an aqueductal stenosis. After numerous revisions she developed an isolated third ventricle, necessitating triventricular shunting to obtain a new equilibrium. An isolated third ventricle is a very rare phenomenon, usually seen in very complex hydrocephalus and only reported on twice before (Filler et al., 1995). Etiological factors postulated in the development of an isolated lateral or fourth ventricle, all seem to contribute also to the development of an isolated third ventricle.

Third ventriculostomy

Since its description by Dandy in 1922, several techniques have been used to perform third ventriculostomy under endoscopic control. Except for the blunt technique, in which the endoscope is used by itself to create the opening in the floor of the third ventricle, the other techniques require more than one instrument to perforate the floor of the ventricle and enlarge the ventriculostomy. The new device described is a sterilizable modified forceps that allows both the opening of the floor and the enlargement of the ventriculostomy in a simple and effective way. The new device has the following characteristics: 1) the tip of the forceps is thin enough to allow the easy perforation of the floor of the ventricle; 2) the inner surface of the jaws is smooth to avoid catching vessels of the basal cistern; and 3) the outer surface of the jaws has indentations that catch the edges of the opening to prevent them from slipping along the instrument's jaws. The ventricle floor is opened by gentle pressure of the forceps, which is slowly opened so that the edges of the aperture are caught by the distal outer indentation of the jaws, leading to an approximately 4-mm opening of the floor. This device has been used successfully in 10 consecutive patients. This new device allows surgeons to perform third ventriculostomy under endoscopic control in a very simple, quick, and effective way, avoiding the need for additional single-use instruments.

Neurobehavioral status and health-related quality of life in newly diagnosed high-grade glioma patients

PURPOSE

To evaluate the health-related quality of life (HRQOL) and cognitive functioning of high-grade glioma patients in the postneurosurgical period.

PATIENTS AND METHODS

The HRQOL, as assessed by the Short-Form Health Survey-36, tumor-specific symptoms, and objective and subjective neuropsychologic functioning, of 68 newly diagnosed glioma patients were compared with that of 50 patients with non-small-cell lung cancer (NSCLC) and to age- and sex-matched healthy controls. The association between tumor lateralization, extent of resection, and use of medication, and the HRQOL outcomes was also investigated.

RESULTS

The HRQOL of the two patient groups was similar but significantly lower than that of the healthy controls. Glioma patients reported significantly more neurologic symptoms and poorer objective and subjective neuropsychologic functioning than the NSCLC patients. Using healthy controls as the reference group, cognitive impairment assessed at the individual patient level was observed in all glioma patients and 52% of the NSCLC patients. Poor performance on timed tasks in the glioma group could be attributed, in large part, to visual and motor deficits. Tumor lateralization was found to affect neuropsychologic functioning in a predictable manner. The extent of resection was not related significantly to neuropsychologic functioning. Corticosteroid use was associated with better recognition memory, whereas antiepileptic drug use was correlated negatively with working memory capacity.

CONCLUSION

The general HRQOL of glioma patients is similar to that of patients with NSCLC. However, they suffer from a number of condition-specific neurologic and neuropsychologic problems that have a significant impact on their daily lives in the postsurgical period, before treatment with radiotherapy.

Contact laser-assisted neuroendoscopy can be performed safely by using pretreated 'black' fibre tips: experimental data

BACKGROUND AND OBJECTIVE

Laser-assisted endoscopic neurosurgery by using conventional fibres requires the use of high-power laser light. Because this is potentially hazardous, we developed a pretreated fibre tip and evaluated tissue effects in vitro and in vivo.

STUDY DESIGN/MATERIALS AND METHODS

By applying a highly absorbing coating to the front of the ball tip, almost all laser light is transformed into thermal energy, instantly producing ablative temperatures at the tip itself. The temperature distribution was examined by using an in vitro thermal imaging technique. The in vivo effect on rabbit cerebral tissue was examined macroscopically and histologically.

RESULTS

By using a conventional fibre tip, ablation was not observed, despite the use of high energy and power (20 W for 10 seconds), whereas histology and thermal imaging demonstrated deleterious effects deeply into the cerebral tissue. By using the coated fibre tip, ablation was observed at low energy and power (1 W for 1 second) with thermal effects restricted to superficial structures.

CONCLUSIONS

We show that laser-assisted neuroendoscopy can only be considered to be safe when pretreated "black" fibre tips are used, as laser light damages deep structures.

Medullary cone movement in subjects with a normal spinal cord and in patients with a tethered spinal cord

PURPOSE

To compare movement of the normal medullary cone when the patient has changed from a supine to prone position with that in patients with known or suspected tethered spinal cord syndrome.

MATERIALS AND METHODS

Fifty-six individuals divided into three groups were examined with lumbar spine magnetic resonance (MR) imaging performed with the patient in the prone and supine positions. Group 1 consisted of 15 healthy volunteers and six patients with a herniated disk; group 2, 25 patients clinically suspected of having a tethered cord; and group 3, 10 patients who previously had undergone tethered cord surgery.

RESULTS

All group 1 subjects showed distinct and statistically significant medullary cone movement (range, 21%--41%); no patient in group 3 showed movement (Wilcoxon rank sum test, P <.001). In group 2, the 20 patients in whom a definite diagnosis of tethered cord syndrome was made on the basis of initial supine MR image findings showed no movement, whereas two of five patients with normal supine MR images had abnormal and decreased cone movement at prone imaging.

CONCLUSION

Prone MR imaging has no additional value when the supine MR image has clearly shown the cause of tethering or in patients who have undergone tethered cord surgery, but it can provide additional information in patients clinically suspected of having a tethered cord and in whom supine MR imaging depicted no abnormalities.

Surgery in adults with tethered cord syndrome: outcome study with independent clinical review

OBJECT

The authors conducted a study to evaluate the risks and short-term benefits of surgical treatment for tethered cord syndrome (TCS) in patients older than 18 years of age.

METHODS

The authors studied a series of 57 consecutive adult patients with TCS of varying origins. Patients were examined by the same neurologist in a standardized fashion before and after surgery, and most were followed for at least 2 years postoperatively. Patient age ranged from 19 to 75 years. The mean age at onset of symptoms and diagnosis was 30 years and 37 years, respectively. Muscle strength improved (15 cases) or showed no change postoperatively (38 cases) in a large majority of patients (93%). In four patients a minor decrease in muscle strength was demonstrated, and there was significant deterioration in two (3.5%). In the two latter patients, a rapid decline in motor function was present preoperatively. Subjective assessment of pain, gait, sensory function, and bladder/bowel function at 4 weeks, 6 months, and 2 years postsurgery revealed improvement in a substantial percentage of patients. No major surgery-related complications occurred.

CONCLUSIONS

This is the largest series to date in which adult patients with TCS comprise the report. Untethering procedures in these patients were safe and effective, at least in the short term. Patients with rapid loss of motor function, lipomyelomeningocele, or split cord malformation seem to be at a higher risk of postsurgery deterioration. A follow-up period of many more years will be necessary to determine whether aggressive surgery is beneficial in the long term.

[Stereotaxic irradiation of vestibular schwannoma (acoustic neuroma)]

A vestibular schwannoma (acoustic neurinoma) is a benign tumour localized in the cerebellopontine angle; it can give rise to cranial nerve symptoms. In recent years stereotactic irradiation has become an alternative to radical surgery. Stereotactic irradiation is administered with a gamma knife unit or with an adapted linear accelerator, as a single fraction (radiosurgery) or fractionated (stereotactic radiation therapy). Stereotactic irradiation gives local control rates of over 90%. Post treatment hearing preservation rate is over 60% and treatment related toxicity is low. Comparable treatment results are also found in the Netherlands at the VU-Ziekenhuis in Amsterdam.

Aneurysm detection with computed tomographic angiography in a 1-month-old infant

We report an infant whose clinical condition deteriorated acutely at 1 month of age because of a subarachnoid hemorrhage with an intracerebellar hematoma. Computed tomographic angiography revealed an aneurysm of the left posterior inferior cerebellar artery. Because of the critical condition of the child and her very young age, the decision to perform surgery was based solely on the computed tomographic angiography findings.

[Children with craniopharyngioma, a 'benign' brain tumor with a high morbidity]

The craniopharyngioma is a histologically benign tumour, mainly occurring in childhood. Neurosurgical treatment, in some of these patients in combination with external radiotherapy, results in a fair prognosis for children with craniopharyngioma. However, the central localisation of this tumour in the brain, damage of surrounding structures due to tumour growth, as well as the adverse effects of treatment will result in substantial morbidity in many patients. The first patient, a 13-year-old boy, presented with symptoms and signs of increased intracranial pressure. Following operation he was treated with radiotherapy, and up to 4 years after the operation there was no tumour recurrence. However, he experienced endocrine, visual, hypothalamic and intellectual disturbances due to the disease and its treatment. The second patient, a 6-year-old girl, presented with hydrocephalus due to the tumour, but also had growth retardation. After operation and radiotherapy, she had visual, endocrine, and intellectual dysfunction, but there were no signs of tumor recurrence. The third patient, an 12-year-old boy, already had growth retardation several years before he presented with neurological dysfunction. He received no postoperative radiation, as all tumour tissue could be removed. He had visual, hypothalamic, endocrine and intellectual disturbances but until nearly 6 years after the operation, there was no tumour recurrence. The morbidity due to the tumour and its treatment has a negative impact on the patient's quality of life. A multidisciplinary treatment and follow-up of these children cannot avoid this morbidity but may result in a timely observation of problems and thereby prevent unnecessary damage.

[Clinical thinking and decision making in practice. A student with sudden headache]

A previously healthy man aged 18 years suddenly developed a severe headache, followed by nausea, vomiting, fever. During the following weeks a left-sided hemiparesis developed. CT of the brain revealed a pansinusitis and a frontal epidural empyema. A few days after surgical drainage his condition deteriorated and subsequent CT showed a right-sided subdural empyema. This was surgically evacuated and followed by long-term high-dose intravenous antibiotic therapy. The patient made a complete recovery. A sudden severe headache can be caused by an intracranial infection and intracranial pus collections can occur in the subdural as well as in the epidural space. Epidural empyema is a limited disease with relatively mild symptoms and a favourable prognosis, whereas subdural empyema may rapidly spread and cause severe disease with a poor prognosis. Quick antibiotic treatment and surgical drainage are required.

An arachnoid cyst presenting as an intramedullary tumour

A case of thoracic intradural extramedullary arachnoid cyst is presented in which an intramedullary low grade glioma was suspected preoperatively. The cyst was widely fenestrated and postoperatively, the patient experienced considerable improvement in her symptoms. As postoperative MRI studies also showed resolution of the intramedullary changes we regard the intramedullary changes as a result of the cyst, without the existence of primary medullary pathology. To our knowledge an arachnoid cyst, to date, has not been described as the cause of syringomyelia. As radiological findings can be misleading, extramedullary pathology, located more cranially, should be ruled out when treating cystic medullary changes.

NMR spectroscopic evaluation of cerebral metabolism in hydrocephalus: a review

Cerebral ischemia contributes to cerebral damage in hydrocephalus. Many studies have reported changes in cerebral blood flow and metabolism, supporting this hypothesis. Magnetic resonance spectroscopy (MRS) enables us to investigate cerebral metabolism in a non-invasive and longitudinal manner, thereby providing a promising way of evaluating pathophysiological changes in experimental and clinical hydrocephalus. In this review, the potential of 1H (proton) and 31P (phosphorus) MRS in the assessment of cerebral metabolism will be summarized, and a synopsis of in vitro and in vivo MRS studies in experimental and human hydrocephalus will be presented. Changes in high-energy phosphate metabolism, intracellular pH and lactate production in several MRS studies are presumed to reflect cerebral ischemia. In vivo information on neuronal damage, maturational delay and membrane phospholipid metabolism may also be derived from 1H and 31P MRS data. Technical, methodological and pathophysiological considerations, which are important for a correct interpretation and comparison of different MRS studies, will be discussed. Finally, we will draw some conclusions on the significance of these MRS findings and the applicability of MRS in the diagnosis and evaluation of clinical hydrocephalus.

Cerebral metabolism in experimental hydrocephalus: an in vivo 1H and 31P magnetic resonance spectroscopy study

OBJECT

Brain damage in patients with hydrocephalus is caused by mechanical forces and cerebral ischemia. The severity and localization of impaired cerebral blood flow and metabolism are still largely unknown. Magnetic resonance (MR) spectroscopy offers the opportunity to investigate cerebral energy metabolism and neuronal damage noninvasively and longitudinally. Previous 1H MR spectroscopy studies have shown an increased lactate resonance that is suggestive of anaerobic glycolysis. The aim of this study was to assess cerebral damage and energy metabolism in kaolin-induced hydrocephalus in adult rats by using in vivo 1H and 31P MR spectroscopy. The presence of lactate was correlated with high-energy phosphate metabolism and intracellular pH. The measurement of relative concentrations of N-acetyl aspartate (NAA), choline (Cho), and total creatine (tCr) served to assess neuronal damage.

METHODS

Hydrocephalus was induced in adult rats by surgical injection of kaolin into the cisterna magna. Magnetic resonance studies, using a 4.7-tesla magnet, were performed longitudinally in hydrocephalic animals at 1 (10 rats), 8 (six rats), and 16 weeks (six rats) thereafter, as well as in eight control animals. To evaluate ventricular size and white matter edema T2-weighted MR imaging was performed. The 1H MR spectra were acquired from a 240-microl voxel, positioned centrally in the brain, followed by localized 31P MR spectroscopy on a two-dimensional column that contained the entire brain but virtually no extracranial muscles. The 1H and 31P MR spectroscopy peak ratios were calculated after fitting the spectra in the time domain, intracellular pH was estimated from the inorganic phosphate (Pi) chemical shift, and T2 relaxation times of 1H metabolites were determined from the signal decay at increasing echo times.

CONCLUSIONS

In hydrocephalic rats, ventricular expansion stabilized after 8 weeks. White matter edema was most pronounced during acute hydrocephalus. Lactate peaks were increased at all time points, without a decrease in phosphocreatine (PCr)/Pi and PCr/adenosine triphosphate (ATP) peak ratios, or pH. Possibly lactate production is restricted to periventricular brain tissue, followed by its accumulation in cerebrospinal fluid, which is supported by the long lactate T2 relaxation time. Alternatively, lactate production may precede impairment of ATP homeostasis. The NAA/Cho and tCr/Cho ratios significantly decreased during the acute and chronic stages of hydrocephalus. These changes were not caused by alterations in metabolite T2 relaxation time. The decreases in the NAA/Cho and tCr/Cho ratios implicate neuronal loss/dysfunction or changes in membrane phospholipid metabolism, as in myelin damage or gliosis. It is suggested that 1H MR spectroscopy can be of additional value in the assessment of energy metabolism and cerebral damage in clinical hydrocephalus.

In vivo 1H MR spectroscopic imaging and diffusion weighted MRI in experimental hydrocephalus

The severity and progression of ventricular enlargement, the occurrence of cerebral edema, and the localization of ischemic metabolic changes were investigated in a rat model of hydrocephalus, using in vivo 1H MR spectroscopic imaging (SI) and diffusion weighted MRI (DW MRI). Hydrocephalic rats were studied 1, 2, 4, and 8 weeks after injection of kaolin into the cisterna magna. Parametric images of the apparent diffusion coefficient (ADC) revealed a varying degree of ventriculomegaly in all rats, with different time courses of ventricular expansion. Extracellular white matter edema was observed during the early stages of hydrocephalus, most extensively in cases of progressive ventriculomegaly. In gray matter regions, ADC values were not changed, compared with controls. In case of fatal hydrocephalus, high lactate levels were observed throughout the whole brain. In all other rats, at all time points after kaolin injection, lactate was detected only in voxels containing cerebrospinal fluid. This suggests accumulation of lactate in the ventricles, and/or an ongoing periventricular production of lactate as a consequence of cerebral ischemia in experimental hydrocephalus.

Correlation between neonatal cranial ultrasound, MRI in infancy and neurodevelopmental outcome in infants with a large intraventricular haemorrhage with or without unilateral parenchymal involvement

During a 7-year-period, 1625 infants of 34 weeks gestation or less were enrolled in a prospective ultrasound (US) study. One hundred and eleven (6.8%) infants developed a large intraventricular haemorrhage (IVH) with or without unilateral parenchymal involvement (PI). Fifty-six of these 111 infants survived (50.4%) and in 23 (41%) of them a magnetic resonance imaging (MRI) study was performed beyond 12 months corrected age. There appeared to be a good agreement between neonatal ultrasound findings and MRI changes noted in infancy. Of the 10 cases with a large IVH without PI (group A), seven had a VP shunt with complete decompression of previously enlarged ventricles. Six of these seven infants had periventricular hyperintensity (PVHI) but none developed cerebral palsy (CP). Two of the ten cases without a VP shunt had irregular ventricular enlargement (VE) with PVHI in one. Both developed CP. Seven cases showed thinning of the corpus callosum. Of the 13 cases with a large IVH associated with PI (group B), the site of the PI could still be recognised on MRI and the degree of communication of the porencephalic cyst (PC) with the lateral ventricles correlated well with neonatal US findings. On MRI, VE was present in only 6 cases. Wallerian degeneration was present in 9/13 infants and all but one developed a hemiplegia. In 12/13 cases there was thinning of the corpus callosum, either focal or diffuse. PVHI was present in all infants. In 6/13 PVHI was only present around the PC. Neurodevelopmental outcome differed for both groups. CP was only present in 2/10 infants in group A, compared to 11/ 13 in group B. Global delay, in the absence of CP, was more common in infants with a large IVH than in those with associated PI.

CONCLUSION

Combining neonatal US with MRI in infancy enhances our understanding of the long-term effects of severe haemorrhagic brain lesions, occurring in preterm infants.

Subarachnoid hemorrhage: aneurysm detection and preoperative evaluation with CT angiography

PURPOSE

To evaluate if computed tomographic (CT) angiography can replace digital subtraction angiography (DSA) for aneurysm detection and as preoperative work-up in patients with subarachnoid hemorrhage (SAH).

MATERIALS AND METHODS

Prospectively, 100 patients with SAH underwent CT angiography; 80 also underwent DSA. Two observers independently evaluated CT angiographic source images and maximum intensity projection slabs. Neurosurgeons compared CT angiograms and DSA images for presurgical evaluation.

RESULTS

On CT angiograms, the observers detected 73 and 70 of 75 symptomatic aneurysms; 96% of the detected aneurysms were classified as definitely present. Of 16 incidental aneurysms, 12 and 10 were detected by the observers. With adequate CT angiographic quality, parent artery side of anterior communicating aneurysms was correctly predicted in 100% (95% confidence interval [CI]: 87%, 100%). Neurosurgeons assessed CT angiography as equal or superior to DSA in 83% (95% CI: 73%, 90%) of 87 aneurysms, and in 74% (95% CI: 63%, 82%) operation might have been based on CT angiographic findings alone.

CONCLUSION

CT angiography depicted 90% of all aneurysms, and 90% were classified as definitely present. CT angiography must be of high quality with adequate depiction of the aneurysm and the parent artery for surgery to be performed on the basis of CT angiographic findings alone.

Recurrent subdural haematoma as the primary and sole manifestation of chronic lymphocytic leukaemia

An 81-year-old man with a recurrent subdural haematoma as the first and only manifestation of chronic lymphocytic leukaemia (CLL) is described. Microscopic examination of the encapsulated haematoma showed leukaemic infiltration and the diagnosis was confirmed by bone marrow aspiration and by pathological examination of the brain at autopsy.

[Methylprednisolone in traumatic spinal cord injuries: not proven to be beneficial to the patient at the present time]

Ever since the publication in 1990 in The New England Journal of Medicine of a multicentre, randomised, double-blind, placebo-controlled trial on the efficacy of methylprednisolone (MP) in the treatment of acute, traumatic spinal cord injury, the advice is to administer MP as soon as possible to every patient presenting a traumatic spinal cord injury. This recommendation has been followed throughout the world, especially by traumatologists, and seems to be above criticism. However, the results of most cited studies, which have had a major influence on the treatment of patients with an acute, traumatic spinal cord lesion, show that the improvements in the neurological condition due to MP cannot be translated into a specific improvement in the functional status. Until it has been proven beyond reasonable doubt that MP can play a significant role in the treatment of these patients, we advise that MP should not be administered to a patient with acute, traumatic spinal cord injury, awaiting the results of more quantitative research. Such research is being performed by the Cochrane Brain and Spinal Cord Injury Group.

Laser-assisted neuroendoscopy using a neodymium-yttrium aluminum garnet or diode contact laser with pretreated fiber tips

OBJECT

Although lasers have proved to be valuable in neuroendoscopy, surgeons are still not comfortable using high-energy laser endoscopic probes in proximity to vital structures such as the basilar artery in third ventriculostomy. The authors have developed a special laser catheter for use in neuroendoscopy; the object of this paper is to present their experimental and clinical experiences using the catheter.

METHODS

This laser catheter is fitted with an atraumatic ball-shaped fiber tip that is pretreated with a layer of carbon particles. These carbon particles absorb approximately 90% of the energy emitted, which is very effectively converted into heat. As the heat is generated in this very thin layer of carbon coating, the temperature at the surface of the ball-shaped tip reaches ablative temperatures instantly at powers of only a few watts per second, which has enabled the authors to limit drastically the amount of laser light used and the length of exposure needed, thereby increasing safety even around critical structures.

CONCLUSIONS

The authors present experimental data and their clinical experience using these pretreated fiber tips with a neodymium-yttrium aluminum garnet contact laser or a diode contact laser in 49 patients (22 males and 27 females) and a variety of procedures: third ventriculocistemostomy (33 patients), cyst fenestration (nine patients), colloid cyst resection (six patients), and fenestration of the septum pellucidum (one patient). There was no instance of mortality or increased morbidity. To date, the procedure success rate is 100% and the overall outcome success rate is 86%. The authors conclude that pretreated atraumatic ball-shaped fiber tips now make laser application safe and effective in a variety of neuroendoscopic procedures. Because of their low power range (only several watts), compact diode lasers will be the energy source of first choice.

Cerebral ischemia and white matter edema in experimental hydrocephalus: a combined in vivo MRI and MRS study

T2 and diffusion weighted MRI, as well as 31P and 1H MRS were performed in kaolin-induced hydrocephalic rats. Extracellular white matter edema was detected in the early stages of progressive hydrocephalus. Phosphocreatine (PCr)/inorganic phosphate (Pi) ratios in hydrocephalic animals were decreased compared to controls, and lactate was detected during the acute and chronic stages of hydrocephalus. These MR spectroscopic results are indicative of a compromised energy metabolism and suggest the occurrence of cerebral ischemia in experimental hydrocephalus.

Hemidystonia as presenting symptom of an optic glioma

The first case is presented of an exophytic chiasmatic-hypothalamic glioma causing progressive hemidystonia in an 8-year-old boy, and all 24 reported cases of intraaxial cerebral tumours resulting in symptomatic hemidystonia are reviewed.

[Clinical judgment and decision making in clinical practice. A free spirit with imminent paraplegia]

A 45-year-old man was admitted because of loss of strength in the legs and urinary retention. MRI showed enlargement of the thoracic and lumbar spinal cord from T11 to the conus medullaris. Magnetic resonance angiography and spinal angiography showed a dural arteriovenous fistula. The abnormal connection was clipped surgically after which the patient recovered fully.

Relationship between anterior fontanelle pressure measurements and clinical signs in infantile hydrocephalus

The treatment of choice in progressive hydrocephalus is drainage of cerebrospinal fluid in order to reduce elevated intracranial pressure (ICP). Defining the right moment for surgical intervention, however, in a hydrocephalic infant on the basis of clinical signs alone can be a difficult task. Clinical signs of raised ICP are known to be unreliable and sometimes even misleading. In the present study, the relationship between long-term anterior fontanelle pressure (AFP) measurements and clinical signs was investigated in 37 infants with hydrocephalus. The decision as to whether to operate or not was based on clinical signs alone; AFP values were not taken into account. There was an overall difference between the non-operated group and the preoperative measurements in the operated group, and also between the preoperative and the postoperative measurements in the latter, in regard to both AFP measurements and clinical signs. Almost all preoperative AFP values were increased. The direct correlation (phi) between most individual clinical signs and AFP levels, however, was low (phi = 0.15-0.41). The clinical sign "tense fontanelle" showed the best correlation with the AFP levels (phi = 0.75). Furthermore, using logistic regression analysis, no combination of clinical signs could be found which reliably predicted the AFP. The relationship between the AFP pressure variables and clinical signs was also examined. The pathological A-waves occurred only in the presence of raised (baseline) AFP, a situation in which considerably more frequent B-waves were observed as well. It was concluded that clinical signs of raised ICP in infantile hydrocephalus are not very reliable and AFP monitoring can therefore provide valuable information on intracranial dynamics in patients with dubious neurological manifestations of progressive hydrocephalus.

Cisplatin-induced autonomic neuropathy: does it really exist?

The neurotoxic side-effects of cisplatin affect predominantly the large, myelinated fibres of peripheral nerves, leading to a sensory neuropathy. Several reports of cisplatin-associated autonomic neuropathy have been published. Autonomic dysfunction however, is caused by a neuropathy of small unmyelinated nerve fibres. By using the absolute pupil diameter as a parameter of autonomic nervous system function, we studied autonomic neuropathy in the eye of cisplatin-intoxicated rats. In addition, we examined autonomic cardiovascular function by measuring the change in heart rate (HR) and mean arterial blood pressure (MAP) in response to intravenous phenylephrine (PHE) and tyramine (TYR). No significant differences in mean pupil diameter developed in cisplatin-intoxicated rats (n = 12) in the course of 9 weeks (total cumulative dose cisplatin 18 mg/kg) compared with normal controls (n = 9) MANOVA, F1,19 = 0.88, P < 0.36). The PHE- and TYR-induced changes in MAP and HR were virtually the same in cisplatin-intoxicated rats when compared with normal controls. We conclude that cisplatin probably does not cause autonomic dysfunction, at least not in rats, in doses commonly used and which are known to cause a peripheral sensory neuropathy.