Prevalence of brain arteriovenous malformations in first-degree relatives of patients with a brain arteriovenous malformation.

BACKGROUND AND PURPOSE: It is uncertain whether familial occurrence of brain arteriovenous malformations (BAVMs) represents coincidental aggregation or a shared familial risk factor. We aimed to compare the prevalence of BAVMs in first-degree relatives (FDRs) of patients with BAVM and the prevalence in the general population. METHODS: We sent a postal questionnaire to 682 patients diagnosed with a BAVM in 1 of 4 university hospitals to retrieve information about the occurrence of BAVMs among their FDRs. We calculated a prevalence ratio using the BAVM prevalence among FDRs and the prevalence from a Scottish population-based study (93 per 628 788 adults). A prevalence ratio of ≥9 with a lower limit of the 95% confidence interval of 3 was considered indicative of a shared familial risk factor. RESULTS: Informed consent was given by 460 (67%) patients, who had 2992 FDRs. We identified 3 patients with a FDR with a BAVM, yielding a prevalence ratio of 6.8 (95% CI, 2.2-21). CONCLUSIONS: The prevalence of BAVMs in FDRs of patients with a BAVM was increased but did not meet our prespecified criterion for a shared familial risk factor. In combination with the low absolute risk of a BAVM in FDRs, our results do not support screening of FDRs for BAVMs.

Extent of bilateral neuronal network reorganization and functional recovery in relation to stroke severity.

Remodeling of neuronal structures and networks is believed to significantly contribute to (partial) restoration of functions after stroke. However, it has been unclear to what extent the brain reorganizes and how this correlates with functional recovery in relation to stroke severity. We applied serial resting-state functional MRI and diffusion tensor imaging together with behavioral testing to relate longitudinal modifications in functional and structural connectivity of the sensorimotor neuronal network to changes in sensorimotor function after unilateral stroke in rats. We found that gradual improvement of functions is associated with wide-ranging changes in functional and structural connectivity within bilateral neuronal networks, particularly after large stroke. Both after medium and large stroke, brain reorganization eventually leads to (partial) normalization of neuronal signal synchronization within the affected sensorimotor cortical network (intraregional signal coherence), as well as between the affected and unaffected sensorimotor cortices (interhemispheric functional connectivity). Furthermore, the bilateral network configuration shifts from subacutely increased "small-worldness," possibly reflective of initial excessive neuronal clustering and wiring, toward a baseline small-world topology, optimal for global information transfer and local processing, at chronic stages. Cortical network remodeling was accompanied by recovery of initially disrupted structural integrity in corticospinal tract regions, which correlated positively with retrieval of sensorimotor functions. Our study demonstrates that the degree of functional recovery after stroke is associated with the extent of preservation or restoration of ipsilesional corticospinal tracts in combination with reinstatement of interhemispheric neuronal signal synchronization and normalization of small-world cortical network organization.

Prognosis of acute subdural haematoma from intracranial aneurysm rupture.

BACKGROUND: Acute subdural haematoma (aSDH) is a rare complication of aneurysmal subarachnoid haemorrhage (SAH) and is associated with poor clinical condition on admission and poor outcome. OBJECTIVE: The aim of this study was to assess whether aneurysmal aSDH is an independent risk factor for poor outcome. METHODS: In a series of 1632 patients retrieved from our prospectively collected single centre SAH database and fulfilling prespecified inclusion criteria, we found 53 patients with aSDH on the initial CT scan. From the same series, we collected 660 patients in whom aSDH was ruled out by reviewing the initial CT scan. We compared the risk of poor outcome at discharge and at 3 months between patients with and without aSDH by calculating crude risk ratios (RRs) with corresponding 95% CIs, and adjusting for age, sex, location and treatment modality of the aneurysm that bled, clinical condition on admission, intracerebral haemorrhage, intraventricular haemorrhage and hydrocephalus, with Poisson regression. RESULTS: Patients with aSDH had a higher risk of poor outcome at discharge (crude RR 1.59; 95% CI 1.35 to 1.86) and at 3 months (crude RR: 2.17, 95% CI 1.79 to 2.62) than patients without aSDH. After simultaneous adjustment for five characteristics that affected the crude RR, the RR for poor outcome for patients with aSDH at discharge was 1.15 (95% CI 0.97 to 1.37) and at 3 months 1.30 (95% CI 1.04 to 1.62). CONCLUSIONS: The presence of aSDH in patients with aneurysmal SAH is an independent risk factor for poor outcome at 3 months.

Natural history of spheno-orbital meningiomas.

BACKGROUND: To investigate the natural history and the growth rate of spheno-orbital meningiomas (SOMs). METHODS: Ninety patients with a diagnosis of SOM were included, and patient charts and imaging were evaluated. In a subset of 32 patients, volumetric studies were performed. RESULTS: The median follow-up for the entire group was 4 years (range, 1-15); the mean age was 47.8 (range, 26-93) years; 94% of the patients were female. The most common clinical signs and symptoms were proptosis (93%), visual deterioration (65%), retro-bulbar pain (23%) and diplopia (6%). In 35% of patients in this series, no visual deterioration occurred, and in 30% only mild proptosis was present. The median annual growth rate of the SOMs in the subset of 32 patients was 0.3 cm³/year (range, 0.03-1.8 cm³/year). We assessed a trend for more rapid tumour growth in younger patients and found the initial volume of the tumour (rho = 0.63) and of the soft tissue component (rho = 074) to be significantly related to the growth rate. CONCLUSION: SOMs are slow-growing tumours that cause primarily proptosis and visual deterioration. In a significant number of patients, these tumours cause minimal discomfort and symptomatology. Therefore, in the absence of risk factors, we advocate a "wait and see" policy. For patients with large SOMs or with a large soft tissue component at first visit or with fast growing SOMs (>1cm³/year), a follow-up examination every 6 months is indicated.

Treatment of brain arteriovenous malformations: a systematic review and meta-analysis.

CONTEXT: Outcomes following treatment of brain arteriovenous malformations (AVMs) with microsurgery, embolization, stereotactic radiosurgery (SRS), or combinations vary greatly between studies. OBJECTIVES: To assess rates of case fatality, long-term risk of hemorrhage, complications, and successful obliteration of brain AVMs after interventional treatment and to assess determinants of these outcomes. DATA SOURCES: We searched PubMed and EMBASE to March 1, 2011, and hand-searched 6 journals from January 2000 until March 2011. STUDY SELECTION AND DATA EXTRACTION: We identified studies fulfilling predefined inclusion criteria. We used Poisson regression analyses to explore associations of patient and study characteristics with case fatality, complications, long-term risk of hemorrhage, and successful brain AVM obliteration. DATA SYNTHESIS: We identified 137 observational studies including 142 cohorts, totaling 13,698 patients and 46,314 patient-years of follow-up. Case fatality was 0.68 (95% CI, 0.61-0.76) per 100 person-years overall, 1.1 (95% CI, 0.87-1.3; n = 2549) after microsurgery, 0.50 (95% CI, 0.43-0.58; n = 9436) after SRS, and 0.96 (95% CI, 0.67-1.4; n = 1019) after embolization. Intracranial hemorrhage rates were 1.4 (95% CI, 1.3-1.5) per 100 person-years overall, 0.18 (95% CI, 0.10-0.30) after microsurgery, 1.7 (95% CI, 1.5-1.8) after SRS, and 1.7 (95% CI, 1.3-2.3) after embolization. More recent studies were associated with lower case-fatality rates (rate ratio [RR], 0.972; 95% CI, 0.955-0.989) but increased rates of hemorrhage (RR, 1.02; 95% CI, 1.00-1.03). Male sex (RR, 0.964; 95% CI, 0.945-0.984), small brain AVMs (RR, 0.988; 95% CI, 0.981-0.995), and those with strictly deep venous drainage (RR, 0.975; 95% CI, 0.960-0.990) were associated with lower case fatality. Lower hemorrhage rates were associated with male sex (RR, 0.976, 95% CI, 0.964-0.988), small brain AVMs (RR, 0.988, 95% CI, 0.980-0.996), and brain AVMs with deep venous drainage (0.982, 95% CI, 0.969-0.996). Complications leading to permanent neurological deficits or death occurred in a median 7.4% (range, 0%-40%) of patients after microsurgery, 5.1% (range, 0%-21%) after SRS, and 6.6% (range, 0%-28%) after embolization. Successful brain AVM obliteration was achieved in 96% (range, 0%-100%) of patients after microsurgery, 38% (range, 0%-75%) after SRS, and 13% (range, 0%-94%) after embolization. CONCLUSIONS: Although case fatality after treatment has decreased over time, treatment of brain AVM remains associated with considerable risks and incomplete efficacy. Randomized controlled trials comparing different treatment modalities appear justified.

Auditory feedback during frameless image-guided surgery in a phantom model and initial clinical experience.

In this study the authors measured the effect of auditory feedback during image-guided surgery (IGS) in a phantom model and in a clinical setting. In the phantom setup, advanced IGS with complementary auditory feedback was compared with results obtained with 2 routine forms of IGS, either with an on-screen image display or with image injection via a microscope. The effect was measured by means of volumetric resection assessments. The authors also present their first clinical data concerning the effects of complementary auditory feedback on instrument handling during image-guided neurosurgery. When using image-injection through the microscope for navigation, however, resection quality was significantly worse. In the clinical portion of the study, the authors performed resections of cerebral mass lesions in 6 patients with the aid of auditory feedback. Instrument tip speeds were slightly (although significantly) influenced by this feedback during resection. Overall, the participating neurosurgeons reported that the auditory feedback helped in decision-making during resection without negatively influencing instrument use. Postoperative volumetric imaging studies revealed resection rates of > or = 95% when IGS with auditory feedback was used. There was only a minor amount of brain shift, and postoperative resection volumes corresponded well with the preoperative intentions of the neurosurgeon. Although the results of phantom surgery with auditory feedback revealed no significant effect on resection quality or extent, auditory cues may help prevent damage to eloquent brain structures.

Implications of Extracranial Distortion in Ultra-High-Field Magnetic Resonance Imaging for Image-Guided Cranial Neurosurgery.

BACKGROUND: Ultra-high-field magnetic resonance imaging (MRI) of the brain is attractive for image guidance during neurosurgery because of its high tissue contrast and detailed vessel visualization. However, high-field MRI is prone to distortion artifacts, which may compromise image guidance. Here we investigate intra- and extracranial distortions in 7-T MRI scans. METHODS: Five patients with and 5 patients without skin-adhesive fiducials received magnetization-prepared T1-weighted 7-T MRI and standard 3-T MRI scans. The 7- and 3-T images were rigidly coregistered and compared. Intracranial distortions were evaluated qualitatively, whereas shifts at the skin surface and shifts of the center positions of skin-adhesive fiducials were measured quantitatively. Moreover, we present an illustrative case of an ultra-high-field image-guided skull base meningioma resection. RESULTS: We found excellent intracranial correspondence between 3- and 7-T MRI scans. However, the average maximum skin shift was 6.8 ± 2.0 mm in group A and 5.2 ± 0.9 mm in group B. The average maximum difference between the skin-adhesive fiducial positions was 5.6 ± 3.1 mm in group B. In our tumor resection case, the meningioma blood supply could be targeted early thanks to 7-T image guidance, which made subsequent tumor removal straightforward. CONCLUSIONS: There are no visible intracranial distortions in magnetization-prepared T1-weighted 7-T MRI cranial images. However, we found considerable extracranial shifts. These shifts render 7-T images unreliable for patient-to-image registration. We recommend performing patient-to-image registration on a routine (computed tomography scan or 3-T magnetic resonance) image and subsequently fusing the 7-T magnetic resonance image with the routine image on the image guidance machine, until this issue is resolved.

Application accuracy in frameless image-guided neurosurgery: a comparison study of three patient-to-image registration methods.

OBJECT: The aim of this study was to compare three patient-to-image registration methods in frameless stereotaxy in terms of their application accuracy (the accuracy with which the position of a target can be determined intraoperatively). In frameless stereotaxy, imaging information is transposed to the surgical field to show the spatial position of a localizer or surgical instrument. The mathematical relationship between the image volume and the surgical working space is calculated using a rigid body transformation algorithm, based on point-pair matching or surface matching. METHODS: Fifty patients who were scheduled to undergo a frameless image-guided neurosurgical procedure were included in the study. Prior to surgery, the patients underwent either computerized tomography (CT) scanning or magnetic resonance (MR) imaging with widely distributed adhesive fiducial markers on the scalp. An extra fiducial marker was placed on the head as a target, as near as possible to the intracranial lesion. Prior to each surgical procedure, an optical tracking system was used to perform three separate patient-to-image registration procedures, using anatomical landmarks, adhesive markers, or surface matching. Subsequent to each registration, the target registration error (TRE), defined as the Euclidean distance between the image space coordinates and world space coordinates of the target marker, was determined. Independent of target location or imaging modality, mean application accuracy (+/- standard deviation) was 2.49 +/- 1.07 mm when using adhesive markers. Using the other two registration strategies, mean TREs were significantly larger (surface matching, 5.03 +/- 2.30 mm; anatomical landmarks, 4.97 +/- 2.29 mm; p < 0.001 for both). CONCLUSIONS: The results of this study show that skin adhesive fiducial marker registration is the most accurate noninvasive registration method. When images from an earlier study are to be used and accuracy may be slightly compromised, anatomical landmarks and surface matching are equally accurate alternatives.

Image-guided vascular neurosurgery based on three-dimensional rotational angiography. Technical note.

Three-dimensional rotational angiography is capable of exquisite visualization of cerebral blood vessels and their pathophysiology. Unfortunately, images obtained using this modality typically show a small region of interest without exterior landmarks to allow patient-to-image registration, precluding their use for neuronavigation purposes. The aim of this study was to find an alternative technique to enable 3D rotational angiography-guided vascular neurosurgery. Three-dimensional rotational angiograms were obtained in an angiographic suite with direct navigation capabilities. After image acquisition, a navigated pointer was used to touch fiducial positions on the patient's head. These positions were located outside the image volume but could nevertheless be transformed into image coordinates and stored in the navigation system. Prior to surgery, the data set was transferred to the navigation system in the operating room, and the same fiducial positions were touched again to complete the patient-to-image registration. This technique was tested on a Perspex phantom representing the cerebral vascular tree and on two patients with an intracranial aneurysm. In both the phantom and patients, the neuronavigation system provided 3D images representing the vascular tree in its correct orientation, that is, the orientation seen by the neurosurgeon through the microscope. In one patient, tissue shift was clearly observed without significant changes in the orientation of the structures. Results in this study demonstrate the feasibility of using 3D rotational angiography data sets for neuronavigation purposes. Determining the benefit of this type of navigation should be the subject of future studies.

Hypomagnesemia after aneurysmal subarachnoid hemorrhage.

OBJECTIVE: Hypomagnesemia frequently occurs in hospitalized patients, and it is associated with poor outcome. We assessed the frequency and time distribution of hypomagnesemia after aneurysmal subarachnoid hemorrhage (SAH) and its relationship to the severity of SAH, delayed cerebral ischemia (DCI), and outcome after 3 months. METHODS: Serum magnesium was measured in 107 consecutive patients admitted within 48 hours after SAH. Hypomagnesemia (serum magnesium <0.70 mmol/L) at admission was related to clinical and initial computed tomographic characteristics by means of the Mann-Whitney U test. Hypomagnesemia at admission and during the DCI onset period (Days 2-12) was related to the occurrence of DCI and hypomagnesemia at admission, and hypomagnesemia that occurred any time during the first 3 weeks after SAH was related to outcome. RESULTS: Hypomagnesemia at admission was found in 41 patients (38%) and was associated with more cisternal (P = 0.006) and ventricular (P = 0.005) blood, a longer duration of unconsciousness (P = 0.007), and a worse World Federation of Neurosurgical Societies scale score at admission (P = 0.001). The crude hazard ratio for DCI with hypomagnesemia at admission was 2.4 (95% confidence interval, 1.0-5.6), and after multivariate adjustment it was 1.9 (95% confidence interval, 0.7-4.7). The hazard ratio of hypomagnesemia from Days 2 to 12 for patients with DCI was 3.2 (range, 1.1-8.9) after multivariate adjustment. The crude odds ratio for poor outcome (Glasgow Outcome Scale score, 1-3) with hypomagnesemia at admission was 2.5 (range, 1.1-5.5). Hypomagnesemia at admission did not contribute to the prediction of outcome in the multivariate model. CONCLUSION: Hypomagnesemia is frequently present after SAH and is associated with severity of SAH. Hypomagnesemia occurring between Days 2 and 12 after SAH predicts DCI.

Orbital meningioma, the Utrecht experience.

AIMS. 1) To evaluate epidemiological data (age, gender, initial complaints, and ophthalmic findings) of a patient cohort with a primary or secondary orbital meningioma. 2) To evaluate the clinical course of these patients. 3) To evaluate the outcome of treatment. PATIENTS AND METHODS. All consecutive patients with a presumed meningioma with orbital involvement seen at the Academic Medical Center, Utrecht, in the period 1/1/1992-31/12/1999 were evaluated retrospectively. RESULTS. Sixty-three patients with either an optic nerve sheath (n = 16) or a sphenoid ridge or tuberculum sellae meningioma (n = 47) were seen (mean age: 41.9 and 47.6 years, respectively); 20 of these had been treated neurosurgically previously. Fifty-three were females. The most frequent initial symptoms in both groups were proptosis and visual complaints. Thirty-three patients were followed without treatment, eight of them showing a lingering worsening of vision and a slow increase of tumor mass. Thirty patients were operated for different reasons (to confirm the diagnosis, or because of decreasing vision, disfiguring proptosis, threatening of the optic chiasm, or severe retrobulbar pain). Life-threatening problems did not occur, cranial nerve damage being the most frequent complication. Macroscopic radical tumor resection was only obtained in about 50% of the operated patients, but immediate (partial) relief of subjective complaints was obtained in up to 90%. A recurrence with clinical symptoms was seen in two patients within the relatively short follow-up period. CONCLUSIONS. Proptosis and, secondly, vision complaints are the most frequent symptoms in patients with either a primary or a secondary orbital meningioma. Their clinical course is extremely variable. Loss of vision is frequently seen in both groups. Orbitoneurosurgical meningioma resection has a high immediate success rate. Damage to cranial nerves is the most frequent complication of meningioma resection.

Risk factors for acute subdural hematoma from intracranial aneurysm rupture.

BACKGROUND: An acute subdural hematoma (aSDH) is a rare complication of aneurysmal subarachnoid hemorrhage (SAH) and is associated with poor clinical condition on admission and poor outcome. Risk factors for the development of an aSDH from aneurysmal rupture are unknown and may help our understanding of how an aSDH develops. OBJECTIVE: To identify risk factors for the development of an aSDH from intracranial aneurysm rupture. METHODS: Patients were selected from our prospectively collected single-center SAH database. From all 1757 patients fulfilling prespecified inclusion criteria, 63 had an aSDH. We assessed sex, age, smoking, hypertension, history of SAH, sentinel headache, location of the ruptured aneurysm, and intracerebral hemorrhage (ICH) as risk factors for an aSDH. Univariable and multivariable risk ratios with corresponding 95% confidence intervals (CIs) were calculated for characteristics with Poisson regression. RESULTS: Multivariable risk ratios were 1.021 (95% CI: 1.001-1.042) for each year increase in age, 2.3 (95% CI: 1.3-3.8) for posterior communicating artery aneurysms, 3.0 (95% CI: 1.5-6.0) for sentinel headache, and 5.2 (95% CI: 3.1-8.9) for ICH. None of the 95 patients (0%; 95% CI: 0%-3.8%) with a ruptured vertebrobasilar aneurysm had an aSDH, which was statistically significantly lower than at other sites (P = .02 for basilar aneurysm; P = .04 for vertebral aneurysm). None of the other studied characteristics had a statistically significant association with an aSDH. CONCLUSION: Increasing age, sentinel headache, ICH, and aneurysms at the posterior communicating artery are independent risk factors for an aSDH. Patients with a basilar or vertebral aneurysm have a low risk of an aSDH.

Validation of exposure visualization and audible distance emission for navigated temporal bone drilling in phantoms.

BACKGROUND: A neuronavigation interface with extended function as compared with current systems was developed to aid during temporal bone surgery. The interface, named EVADE, updates the prior anatomical image and visualizes the bone drilling process virtually in real-time without need for intra-operative imaging. Furthermore, EVADE continuously calculates the distance from the drill tip to segmented temporal bone critical structures (e.g. the sigmoid sinus and facial nerve) and produces audiovisual warnings if the surgeon drills in too close vicinity. The aim of this study was to evaluate the accuracy and surgical utility of EVADE in physical phantoms. METHODOLOGY/PRINCIPAL FINDINGS: We performed 228 measurements assessing the position accuracy of tracking a navigated drill in the operating theatre. A mean target registration error of 1.33±0.61 mm with a maximum error of 3.04 mm was found. Five neurosurgeons each drilled two temporal bone phantoms, once using EVADE, and once using a standard neuronavigation interface. While using standard neuronavigation the surgeons damaged three modeled temporal bone critical structures. No structure was hit by surgeons utilizing EVADE. Surgeons felt better orientated and thought they had improved tumor exposure with EVADE. Furthermore, we compared the distances between surface meshes of the virtual drill cavities created by EVADE to actual drill cavities: average maximum errors of 2.54±0.49 mm and -2.70±0.48 mm were found. CONCLUSIONS/SIGNIFICANCE: These results demonstrate that EVADE gives accurate feedback which reduces risks of harming modeled critical structures compared to a standard neuronavigation interface during temporal bone phantom drilling.

MRI of bilateral sensorimotor network activation in response to direct intracortical stimulation in rats after unilateral stroke.

Reinstatement of perilesional activation and connectivity may underlie functional recovery after stroke. To measure activation responsiveness in perilesional cortex in relation to white matter integrity, we performed functional functional magnetic resonance imaging during stimulation of the contralesional cortex, together with diffusion tensor imaging, 3 and 28 days after stroke in rats. Despite disturbed sensorimotor function and abnormal callosal appearance at day 3, activation amplitudes were preserved in the perilesional sensorimotor cortex, although time-to-peak was significantly delayed. This indicates that in spite of dysfunction, perilesional cortical tissue can be activated subacutely after stroke, while delay of the hemodynamic activation response suggests impaired neurovascular coupling.

Surgical treatment of sphenoorbital meningiomas.

AIM: To evaluate the outcome of surgery and radiotherapy in the treatment of sphenoorbital meningioma (SOM). METHOD: A retrospective study of 66 consecutive cases treated with surgery for SOM with a minimum follow-up of 4 years. Clinical and radiological information were compared before and after the following surgical approaches: frontotemporal craniotomy, frontotemporal craniotomy combined with orbitozygomatic resection and extended lateral orbitotomy alone. RESULTS: The median age at presentation was 46 years (range, 26-68 years) and the median follow-up after surgery was 102 months (range, 48-288 months). In total, 48 (73%) patients showed preoperative visual deterioration, with visual field defects. All patients had proptosis at presentation (mean ± SD=6.4 ± 3.0 mm). Surgery for patients with SOM arrested visual deterioration in 61% and improved vision in 30% of cases. Furthermore, a substantial reduction of proptosis was achieved in 85% of patients. The proptosis in this group was reduced by 2.6 ± 2.6 mm. There was no correlation between surgical approach and proptosis reduction (p = 0.125). The recurrence rate was 17%. Only 1 out of 15 patients who underwent radiotherapy showed signs of recurrence. CONCLUSIONS: The surgical aims in the treatment of SOM should be the restoration of visual acuity and reduction of proptosis, rather than complete tumour removal. The surgical approach can be tailored to individual cases. The authors recommend radiotherapy in cases of subtotally removed SOM.

A bundle approach to reduce the incidence of external ventricular and lumbar drain-related infections.

OBJECT: An important complication of external CSF drainage is bacterial meningitis or ventriculitis, resulting in increased morbidity, mortality, and health care costs. In 2003, a high rate (37%) of probable drain-related infections was identified at the authors' hospital. A multidisciplinary working group was installed to reduce this incidence to < 10% within 1.5 years. METHODS: An intervention strategy based on 5 pillars (increased awareness, focused standard operating procedures, a diagnostic and therapeutic algorithm, timely administration of prophylaxis, and improvement of the drainage system) was designed and implemented from 2004 to 2006. During this period all patients with external CSF drainage were prospectively monitored. RESULTS: Between 2004 and 2006, there were 467 patients in whom 579 drains (external ventricular and external lumbar) had been placed. The overall incidence of drain-related infections was 16.2% in 2004, 8.9% in 2005, and 11.3% in 2006. For external lumbar drains the number of infections per 100 drain days was 2.4 in 2004, 0.6 in 2005, and 0.8 in 2006. For external ventricular drains these rates were 1.7, 1.0, and 1.2, respectively. Meanwhile, the causative noncutaneous microorganisms, indicative for systemic-contamination during manipulation, decreased. By retrospective analysis, the proportion of patients with a probable drain-related infection decreased from 37% in 2003 to 9% in 2005 and 2006. CONCLUSIONS: The authors' multidisciplinary approach in which different preventive measures were combined was associated with a significant reduction in the incidence of drain-related secondary meningitis, and thus provides an important improvement of patient safety.