Peter Lindvall

Anticoagulants and antiplatelet agents and the risk of development and recurrence of chronic subdural haematomas

Seventy-one patients from northern Sweden were diagnosed with chronic subdural haematomas (CSDH) and treated at the Department of Neurosurgery at Umeå University Hospital over 12 months. Fifty-four patients with CSDH had a history of head trauma (trauma group), while 17 patients had no previous head trauma (non-trauma group). In the non-trauma group 71% of patients were treated with anticoagulants or antiplatelet aggregation agents (AAA) compared to 18% in the trauma group. Considering only AAA, 59% of the non-trauma patients were treated with these drugs versus 17% of patients in the trauma group. The recurrence rate for all patients was 17%. These findings confirm that the use of anticoagulants and AAA is over-represented in patients with non-traumatic CSDH. In our study, recurrence was not associated with previous use of anticoagulants or AAA.

Hypofractionated Conformal Stereotactic Radiotherapy for Arteriovenous Malformations

OBJECTIVEArteriovenous malformations (AVMs) are congenital vascular lesions that are associated with high morbidity and mortality if left untreated. There are several options for treatment, including radiotherapy. Safe and effective single-fraction radiotherapy for patients with large AVMs has been considered difficult. METHODSBetween December 1986 and June 2001, 36 patients with cerebral AVMs were treated with hypofractionated conformal stereotactic radiotherapy at Umeå University Hospital. Twenty-nine patients have been followed angiographically to date and are reported in this study. RESULTSTwenty-four (83%) of 29 patients (mean AVM volume, 11.5 cm3) underwent complete obliteration of their AVMs. The rates of angiographically verified total obliteration at 2 years after treatment were 56% for AVMs 4 to 10 cm3 and 50% for AVMs larger than 10 cm3. The obliteration rate increased considerably with extended follow-up. Five years after treatment, the obliteration rates were 81% for AVMs 4 to 10 cm3 and 70% for AVMs larger than 10 cm3. CONCLUSIONHypofractionated conformal stereotactic radiotherapy may be an important alternative to single-fraction radiotherapy in patients with large AVMs or AVMs located in eloquent areas, because it allows the administration of a higher radiation dose than is possible to deliver in single-fraction radiosurgery. With our technique of hypofractionated conformal stereotactic radiotherapy, the rate of obliterating AVMs was comparable to that of single-dose radiosurgery, although the volumes of the irradiated AVMs in our study were larger than those reported previously.

Complications following cranioplasty using autologous bone or polymethylmethacrylate—Retrospective experience from a single center

OBJECTIVE A decompressive hemicraniectomy is a potentially life-saving intervention following head trauma. Once performed patients are obliged to undergo a second procedure with cranioplasty. Two of the most commonly used materials are autologous bone and polymethylmethacrylate (PMMA). We have now evaluated complications following a cranioplasty using these materials. MATERIALS AND METHODS During a 7-year period (2002-2008) 49 patients were operated with a decompressive craniectomy following head trauma. Patients received a cranioplasty consisting of autologous bone (30 patients, 61.2%) or PMMA (19 patients, 38.8%) and were followed at least 24 months. Patient data were collected retrospectively. RESULTS Twenty patients (20/49, 40.8%) experienced a complication that prompted a re-operation. There was a significantly higher rate of complications leading to a re-operation (53.3% vs. 21.1%, p=0.03) and a shorter survival time of the cranioplasty (mean 48.1 ± 7.8 vs. 79.5 ± 9.0 months, p=0.035) in patients with autologous bone compared to PMMA. Bone resorption and the presence of postoperative hematomas were significantly more common in patients with autologous bone. The material used for cranioplasty was the only variable that significantly correlated to the rate of complications. CONCLUSIONS In our series we had a high percentage of patients needing re-operation due to complications following a cranioplasty. Though generally considered a straightforward procedure, complications and associated morbidity in patients undergoing cranioplasty should not be underestimated.

The Fisher grading correlated to outcome in patients with subarachnoid haemorrhage

Cerebral vasospasm is the major cause of delayed ischemia in patients with subarachnoid haemorrhage (SAH). The Fisher grading scale has been used to predict patients in risk of developing vasospasm. Improved radiological techniques and treatment may have changed the relevance of the Fisher scale. We have now evaluated the Fisher scale, Hunt and Hess and age in relation to outcome in patients with SAH. Eighty- three patients were admitted with SAH during two years, and 84 aneurysms were treated in 78 patients. The Glasgow outcome score (GOS) within 3 months were as follows; GOS 1 (19%), GOS 2 (2%), GOS 3 (11%), GOS 4 (9%), GOS 5 (59%). There was a significant correlation between both the Fisher grading scale, Hunt and Hess scale and outcome. Age was not correlated to the Fisher grading scale or the Hunt and Hess scale. Age was also not correlated to outcome in our patients. Despite the correlation to outcome both Hunt and Hess and the Fisher grading scale had a limited predictive value of outcome due to a low specificity and/or sensitivity.

Reoperation After Failed Deep Brain Stimulation for Essential Tremor

OBJECTIVE To evaluate the effects of reoperation with deep brain stimulation (DBS) in the caudal zona incerta (cZi) in patients with failed DBS in the ventral intermediate (Vim) nucleus of the thalamus for essential tremor. METHODS The results of reoperation with cZi DBS in five patients with failed Vim DBS were retrospectively analyzed. RESULTS Two patients had early failure of Vim DBS, and three after several years of good effect. The mean deviation from the atlas Vim target point was 1.4 mm. Before the reoperation Vim DBS improved hand function and tremor in the treated hand at 25 %, whereas cZi DBS achieved an improvement of 57%. Although cZi was more efficient than Vim DBS, also in the patients with late failure of Vim DBS, they still exhibited a considerable residual tremor on cZi DBS. CONCLUSIONS The effect on tremor was, in this small sample population, improved by implanting an electrode in the cZi. The effect was modest in those patients suffering a deterioration years after the initial operation.

Radiation schedules in relation to obliteration and complications in hypofractionated conformal stereotactic radiotherapy of arteriovenous malformations

Aims: The purpose of this investigation was to assess the obliteration rate and complications following different radiation schedules of hypofractionated conformal stereotactic radiotherapy for cerebral arteriovenous malformations (AVMs). Methods: Twenty-five patients were treated with 35 Gy in 5 fractions, whereas 31 patients were treated with 30–32.5 Gy (mean: 31.6 ± 0.23 Gy) in 5 fractions. A complete angiographic follow-up is available for 40 patients. Results: Thirty-seven out of 40 patients (92.5%) have so far shown obliteration of their AVMs after a mean time of 3.2 ± 0.26 years (range: 2–8 years). The mean AVM volume in these patients was 8.2 ± 1.0 cm3 (range: 1.5–29 cm3). There was a higher rate of obliteration (88%) in patients treated with 35 Gy compared to those treated with <35 Gy (78%), even if this was not statistically significant. There was a significantly shorter time to obliteration in patients treated with 35 Gy. All patients who experienced symptomatic radionecrosis belonged to the group treated with 35 Gy. Conclusion: A radiation schedule of 35 Gy in 5 fractions may be more effective than a radiation schedule of <35 (30–32.5) Gy in obliterating AVMs. This may, however, be at the price of an increased risk of symptomatic radionecrosis.

Cortisol levels are influenced by sedation in the acute phase after subarachnoid haemorrhage.

Subarachnoid haemorrhage (SAH) is a life‐threatening condition that may be aggravated by acute pituitary damage and cortisol insufficiency. Robust diagnostic criteria for critical illness‐related corticosteroid insufficiency (CIRCI) are lacking.

Long-Term Follow-Up of Intracranial Aneurysms Treated With Endovascular Coiling Experience From One Institution

Background: Our aim was to evaluate the long-term treatment results in patients with intracranial aneurysms treated with endovascular techniques. Methods: Forty-four patients treated due to intracranial aneurysms between 1996 and 2002 were investigated with a time-of-flight sequence magnetic resonance angiography (TOF MRA). Results: Depending on the assessment, 47% to 51% of the treated aneurysms had a residual neck at the last digital subtraction angiography follow-up. There was filling of the aneurysm base (2%) in only 1 patient, whereas the remaining aneurysms were totally occluded. A TOF MRA performed 6 to 14 (mean 9.68) years after the last procedure showed a stable result in 93.9% of the treated aneurysms. There were no de novo aneurysms and previously untreated aneurysms were unchanged in size. Conclusion: Our long-term follow-up showed a stable result in previously coiled intracranial aneurysms.

Liquid ionization chamber calibrated gel dosimetry in conformal stereotactic radiotherapy of brain lesions

Hypofractionated conformal stereotactic radiotherapy (HCSRT) is an established method of treating brain lesions such as arteriovenous malformations (AVMs) and brain metastases. The aim of this study was to investigate the reliability of treatment plans in the terms of dose distribution and absorbed dose for HCSRT. Methods and materials. Treatment plans for three different clinical intracerebral targets, AVMs, were transferred to a CT study of a spherical water filled phantom simulating the human head and recalculated for the phantom geometry using a standard treatment planning system utilizing a pencil beam algorithm for dose calculation. The calculated absorbed dose, relative three dimensional (3D) dose distribution and dose conformity were investigated using gel dosimetry normalized to liquid ionization chamber (LIC) measurements. Results. The measured absorbed dose to the dose reference point was found to be within 2% of the calculated dose for all three targets. The measured dose distribution was found to be within 3% and 2 mm of the calculated dose for more than 93% of all points in the target volume for all three targets. Conclusions. The results show that the investigated standard treatment planning system can correctly predict the absorbed dose and dose distribution in different types of intracerebral targets and that the treatment can be delivered according to the plan.

Hypofractionated stereotactic radiotherapy in medium-sized to large arteriovenous malformations

We have reviewed treatment results in terms of obliteration and complications in 24 patients with medium to large sized cerebral arteriovenous malformations (AVMs) (mean volume 18.5±8.9cm(3); range: 10-42) treated with hypofractionated stereotactic radiotherapy (HSRT). AVMs are congenital lesions associated with a high morbidity and mortality. Radiosurgery is one option for treatment. However, in larger AVMs with volumes exceeding 10cm(3) obliteration rates are less favourable and radiation induced complications more frequent. For larger AVMs, volume-staged radiosurgery is one option while another option may be the use of HSRT. Patients were treated with 6-7Gy in five fractions to a total dose of 30-35Gy (mean total dose 32.9±1.6Gy [standard error of the mean]). Sixteen patients (69.6%) showed obliteration after a mean time of 35.2±14.8 months (range: 24-60). Only one patient (4.2%) experienced symptomatic radionecrosis. Our treatment with HSRT seems safe and efficient for treatment of medium to large sized AVMs. Treatment results seem to be in line with volume-staged radiosurgery and may be an alternative for AVMs not suitable for single fraction radiosurgery.