ACE-inhibitors: a preventive measure for bone flap resorption after autologous cranioplasty?

OBJECTIVEDecompressive craniectomy (DC) is an established treatment for refractory intracranial hypertension. It is usually followed by autologous cranioplasty (AC), the reinsertion of a patient's explanted bone flap. A frequent long-term complication of AC is bone flap resorption (BFR), which results in disfigurement as well as loss of the protective covering of the brain. This study investigates risk factors for BFR after AC, including medical conditions and antihypertensive drug therapies, with a focus on angiotensin-converting enzyme inhibitors (ACEIs), which have been associated with a beneficial effect on bone healing and bone preservation in orthopedic, osteoporosis, and endocrinology research.METHODSIn this single-center, retrospective study 183 consecutive cases were evaluated for bone flap resorption after AC. Information on patient demographics, medical conditions, antihypertensive therapy, and BFR-defined as an indication for revision surgery established by a neurosurgeon based on clinical or radiographic assessments-was collected. A Kaplan-Meier analysis of time from AC to diagnosis of BFR was performed, and factors associated with BFR were investigated using the log-rank test and Cox regression.RESULTSA total of 158 patients were considered eligible for inclusion in the data analysis. The median follow-up time for this group was 2.2 years (95% CI 1.9-2.5 years). BFR occurred in 47 patients (29.7%), with a median time to event of 3.7 years (95% CI 3.3-4.1 years). An ACEI prescription was recorded in 57 cases (36.1%). Univariate Kaplan-Meier analysis and the log-rank test revealed that ACEI therapy (2-year event free probability [EFP] 83.8% ± 6.1% standard error vs 63.9% ± 5.6%, p = 0.02) and ventriculoperitoneal (VP) shunt treatment (2-year EFP 86.9% ± 7.1% vs 66% ± 5.0%, p = 0.024) were associated with a lower probability of BFR. Multiple Cox regression analysis showed ACEI therapy (HR 0.29, p = 0.012), VP shunt treatment (HR 0.278, p = 0.009), and male sex (HR 0.500, p = 0.040) to be associated with a lower risk for BFR, whereas bone fragmentation (HR 1.92, p = 0.031) was associated with a higher risk for BFR.CONCLUSIONSHypertensive patients treated with ACEIs demonstrate a lower rate of BFR than patients treated with other hypertensive medications and nonhypertensive patients. Our results are in line with previous reports on the positive influence of ACEIs on bone healing and preservation. Further analysis of the association between ACEI treatment and BFR development is needed and will be evaluated in a multicenter prospective trial

Efficiency of Iterative Metal Artifact Reduction Algorithm (iMAR) Applied to Brain Volume Perfusion CT in the Follow-up of Patients after Coiling or Clipping of Ruptured Brain Aneurysms.

Metal artifacts resulting from coiling or clipping of a brain aneurysm degrade image quality and reduce diagnostic usefulness of computed tomography perfusion CTP. Our aim was to assess the diagnostic value of the iterative metal artifact reduction algorithm (iMAR) in CTP studies after coiling or clipping of ruptured intracranial aneurysms. Fifty-eight CTP exams performed in 32 patients were analysed. iMAR was applied to the source images from the CT scanner. Perfusion maps were generated from datasets both with and without iMAR, and both datasets were compared qualitatively and quantitatively. Qualitative analysis included evaluation of intensity of artifacts, image quality, presence of new artifacts, and the reader's confidence in their diagnosis as well as diagnostic impression. Quantitative analysis included evaluation of tissue attenuation curves, evaluation of region of interest (ROI)-based measurement of perfusion values at levels that do and do not contain metal, compared to previously published reference ranges of perfusion values. Our results showed that application of iMAR reduced artifacts and significantly improved image quality. New artifacts were observed adjacent to metallic implants, but did not limit the evaluation of other regions. After correction for artifact readers' confidence in their diagnosis increased from 41.3% to 87.9%, and the diagnostic impression changed in 31% of the exams. No difference between tissue attenuation curves was found. For slices without metal, no difference was noted between values measured before and after iMAR, and the total number of ROIs in the reference range of perfusion values was unchanged. At the level of the metal implant, 89.85% of ROIs obtained before using iMAR showed calculation errors. After using iMAR, only 1.7% showed errors. Before iMAR 3.1% of values were in the reference range, whereas after iMAR this increased to 33.1%. In conclusion, our results show that iMAR is an excellent tool for reducing artifacts in CTP. It is therefore recommended for use in clinical practice, particularly when severe artifacts are present, or when hypoperfusion is suspected at the level of the coil or clip. After the application of iMAR, the perfusion values at the level of the metal can be better calculated, but may not lie within the reference range; therefore, quantitative analysis at the level of artifacts is not advisable

Long-term results of endoscopic third ventriculostomy: an outcome analysis.

OBJECT Endoscopic third ventriculostomy (ETV) is the procedure of choice in the treatment of obstructive hydrocephalus. The excellent clinical and radiological success rates are well known. Nevertheless, very few papers have addressed the very long term outcomes of the procedure in very large series. The authors present a large case series of 113 patients who underwent 126 ETVs, and they highlight the initial postoperative outcome after 3 months and long-term follow-up with an average of 7 years. METHODS All patients who underwent ETV at the Department of Neurosurgery, Mainz University Hospital, between 1993 and 1999 were evaluated. Obstructive hydrocephalus was the causative pathology in all cases. RESULTS The initial clinical success rate was 82% and decreased slightly to 78% during long-term follow-up. Long-term success was analyzed using Kaplan-Meier curves. Overall, ETV failed in 31 patients. These patients underwent a second ETV or shunt treatment. A positive impact on long-term success was seen for age older than 6 months, and for obstruction due to cysts or benign aqueductal stenosis. The complication rate was 9% with 5 intraoperative and 5 postoperative events. CONCLUSIONS The high clinical success rate in short-term and long-term follow-up confirms ETV's status as the gold standard for the treatment of obstructive hydrocephalus, especially for distinct pathologies. The patient's age and underlying pathology may influence the outcome. These factors should be considered carefully preoperatively by the surgeon

Using an orbit shield during volume perfusion CT: is it useful protection or an obstacle?

AIM To evaluate the image quality and artefacts resulting from in-plane orbit shielding during computed tomography (CT) perfusion and to assess the possibility of artefact reduction using the iterative metal artefact reduction (iMAR) algorithm. MATERIALS AND METHODS Twenty-eight perfusion CT examinations obtained from 20 patients using orbit shields were included in this study. Source images and perfusion maps were analysed retrospectively to detect the type and extent of artefacts. Original images were compared with images processed using the iMAR algorithm. The extent of artefacts was categorised into three groups: orbital/frontal, middle fossa, and posterior fossa. Types of artefacts in source images were categorised as noise, streak, beam hardening, or a combination of those, and types of artefacts in perfusion maps were categorised as: noise, image distortion, areas with missing colour codes, or incorrect colour-coding. RESULTS All source images evaluated showed artefacts related to orbit shielding and 85.7% reached the posterior fossa. In 92.8% of scans, perfusion maps showed artefacts, mostly as incorrect colour codes. Of the perfusion maps with artefacts, 92.3% reached the posterior fossa. After application of the iMAR algorithm, an increase in the extent of artefacts was observed in 93% of perfusion maps, and no improvement of image quality was noted. CONCLUSION Orbit shields cause significant artefacts if used for in-plane shielding during whole-brain CT perfusion, and render areas at the level of the shield undiagnosable. Usage of an orbit shield during whole-brain CT perfusion is not recommended, so alternative methods for reducing the radiation dose are advisable

Long term follow-up of repeat endoscopic third ventriculostomy in obstructive hydrocephalus.

OBJECTIVE Endoscopic third ventriculostomy (ETV) is a safe and less invasive treatment strategy for patients with obstructive hydrocephalus and provides excellent outcome. Nevertheless, repeat ETV in cases of ETV failure is a controversial issue. METHODS Between 1993 and 1999, 113 patients underwent a total of 126 ETVs at the Department of Neurosurgery, Mainz University Hospital. Obstructive hydrocephalus was the causative pathology in all cases. A very long term follow-up of up to 16 years could be achieved. All medical reports of patients who received ETV were reviewed and analyzed with focus on ETV failure with following repeat ETV and its initial as well as very long term success. RESULTS Thirty-one events of ETV failure occurred during the follow-up period. Thirteen patients underwent repeat ETV: three patients during the first 3 months (early repeat ETV), the other 10 patients after 7 to 78 months (late repeat ETV, mean 33 months). All repeat ETV were performed without complications. Follow-up evaluation after successful repeat ETV ranged from < 1 month up to 14 years (mean 7 years). Of the three early revisions, two failed and one other patient died during follow-up while only two of the late repeat ETV failed. Very long term success rate of late repeat ETV up to 14 years yielded 80%. CONCLUSIONS Repeat ETV in cases of late ETV failures represents an excellent option for CSF circulation restoration up to 14 years of follow-up. Repeat ETV in early ETV failure in contrast is not favored by the performing surgeons; and factors of ETV failure should be analyzed very carefully before a decision for repeat ETV is made

Anesthesia modality does not affect clinical outcomes of intra-arterial vasodilator treatment in patients with symptomatic cerebral vasospasms.

Background: Delayed cerebral ischemia and cerebral vasospasm remain the leading causes of poor outcome in survivors of aneurysmal subarachnoid hemorrhage. Refractory cerebral vasospasms can be treated with endovascular vasodilator therapy, which can either be performed in conscious sedation or general anesthesia. The aim of this study is to compare the effect of the anesthesia modality on long-term clinical outcomes in patients undergoing endovascular vasodilator therapy due to cerebral vasospasm and hypoperfusion. Methods: Modified Rankin Scale (mRS) scores were retrospectively analyzed at time of discharge from the hospital and six months after aneurysmal subarachnoid hemorrhage. Additionally, National Institutes of Health Stroke Scale (NIHSS) was assessed 24 hours before, immediately before, immediately after, and 24 hours after endovascular vasodilator therapy, and at discharge and six months. Interventional parameters such as duration of intervention, choice and dosage of vasodilator and number of arteries treated were also recorded. Results: A total of 98 patients were included in this analysis and separated into patients who had interventions in conscious sedation, general anesthesia and a mix of both. Neither mRS at discharge nor at six months showed a significant difference for functionally independent outcomes (mRS 0-2) between groups. NIHSS before endovascular vasodilator therapy was significantly higher in patients receiving interventions in general anesthesia but did not differ anymore between groups six months after the initial bleed. Conclusion: This study did not observe a difference in outcome whether patients underwent endovascular vasodilator therapy in general anesthesia or conscious sedation for refractory cerebral vasospasms. Hence, the choice should be made for each patient individually

Frequent Diagnostic Under-Grading in Isocitrate Dehydrogenase Wild-Type Gliomas due to Small Pathological Tissue Samples.

BACKGROUND In contrast to isocitrate dehydrogenase (IDH) mutation analysis, which is homogenous within a given tumor, diagnostic errors in histological analysis following the 2016 World Health Organization (WHO) classification could be due to small samples because of histological heterogeneity. OBJECTIVE To assess whether the sample size sent to histopathology influences the tumor grading in IDH wild-type gliomas. METHODS Histologically diagnosed WHO grade, sample volume, and preoperative tumor volume data of 111 patients aged who received resection of IDHwt gliomas between January 2007 and December 2015 at our hospital were evaluated. The differences between absolute and relative pathological sample sizes stratified by WHO grade were conducted using One-Way-Permutation-Test. RESULTS With a mean sample size of 10.9 cc, 83.8% of patients were histologically diagnosed as WHO grade IV, while 16.2% of patients with a mean sample size of 2.62 cc were diagnosed as WHO grade II/III. One-Way-Permutation-Test showed a significant difference between absolute tissue samples stratified by WHO grade (P = .0374). The distribution of preoperative tumor volumes with WHO grade IV vs WHO grade II/III showed no significant difference (P = .8587). Of all tumors with a sample size >10 cc 100% were pathologically diagnosed as WHO grade IV and those with sample size >5 cc 93.5% were diagnosed as WHO grade IV. CONCLUSION Small sample sizes are associated with a higher risk of under-estimating malignancy in histological grading in IDHwt gliomas. This study suggests a standard minimum sample size (>5cc) in every resection. Modalities of adjuvant treatment for IDHwt, WHO grade II/III gliomas need to reflect a prognosis that is only marginally better than of a glioblastoma

ACE-inhibitors: a preventive measure for bone flap resorption after autologous cranioplasty?

OBJECTIVEDecompressive craniectomy (DC) is an established treatment for refractory intracranial hypertension. It is usually followed by autologous cranioplasty (AC), the reinsertion of a patient's explanted bone flap. A frequent long-term complication of AC is bone flap resorption (BFR), which results in disfigurement as well as loss of the protective covering of the brain. This study investigates risk factors for BFR after AC, including medical conditions and antihypertensive drug therapies, with a focus on angiotensin-converting enzyme inhibitors (ACEIs), which have been associated with a beneficial effect on bone healing and bone preservation in orthopedic, osteoporosis, and endocrinology research.METHODSIn this single-center, retrospective study 183 consecutive cases were evaluated for bone flap resorption after AC. Information on patient demographics, medical conditions, antihypertensive therapy, and BFR-defined as an indication for revision surgery established by a neurosurgeon based on clinical or radiographic assessments-was collected. A Kaplan-Meier analysis of time from AC to diagnosis of BFR was performed, and factors associated with BFR were investigated using the log-rank test and Cox regression.RESULTSA total of 158 patients were considered eligible for inclusion in the data analysis. The median follow-up time for this group was 2.2 years (95% CI 1.9-2.5 years). BFR occurred in 47 patients (29.7%), with a median time to event of 3.7 years (95% CI 3.3-4.1 years). An ACEI prescription was recorded in 57 cases (36.1%). Univariate Kaplan-Meier analysis and the log-rank test revealed that ACEI therapy (2-year event free probability [EFP] 83.8% ± 6.1% standard error vs 63.9% ± 5.6%, p = 0.02) and ventriculoperitoneal (VP) shunt treatment (2-year EFP 86.9% ± 7.1% vs 66% ± 5.0%, p = 0.024) were associated with a lower probability of BFR. Multiple Cox regression analysis showed ACEI therapy (HR 0.29, p = 0.012), VP shunt treatment (HR 0.278, p = 0.009), and male sex (HR 0.500, p = 0.040) to be associated with a lower risk for BFR, whereas bone fragmentation (HR 1.92, p = 0.031) was associated with a higher risk for BFR.CONCLUSIONSHypertensive patients treated with ACEIs demonstrate a lower rate of BFR than patients treated with other hypertensive medications and nonhypertensive patients. Our results are in line with previous reports on the positive influence of ACEIs on bone healing and preservation. Further analysis of the association between ACEI treatment and BFR development is needed and will be evaluated in a multicenter prospective trial

Subdural versus subgaleal drainage for chronic subdural hematomas: a post hoc analysis of the TOSCAN trial.

OBJECTIVE The use of subdural drains after surgical evacuation of chronic subdural hematoma (CSH) decreases the risk of recurrence and has become the standard of care. Halfway through the controlled, randomized TOSCAN (Randomized Trial of Follow-up CT after Evacuation of Chronic Subdural Hematoma) trial, the authors' institutional guidelines changed to recommend subgaleal instead of subdural drainage. The authors report a post hoc analysis on the influence of drain location in patients participating in the TOSCAN trial. METHODS The study involved 361 patients enrolled in the TOSCAN trial. The patients were stratified according to whether they received surgery before (cohort A) or after (cohort B) the change in institutional protocol. An intention-to-treat analysis was performed with surgery for recurrence as the primary endpoint. Secondary endpoints were outcome-based on modified Rankin Scale scores, seizures, infections, parenchymal brain injuries, and hematoma diameter. RESULTS Of the 361 patients included in the analysis, 214 were stratified into cohort A (subdural drainage recommended), while 147 were stratified into cohort B (subgaleal drainage recommended). There was a 31.78% rate of crossover from the subdural to the subgaleal drainage insertion site due to technical or anatomical difficulties. No differences in the rates of reoperation (21.5% [cohort A] vs 25.17% [cohort B], OR 0.81, 95% CI 0.50-1.34, p = 0.415), infections (0.47% [cohort A] vs 2.04% [cohort B], OR 0.23, 95% CI 0.02-2.19, p = 0.199), seizures (3.27% [cohort A] vs 2.72% [cohort B], OR 1.21, 95% CI 0.35-4.21, p = 0.765), or favorable outcomes (modified Rankin Scale score 0-3) at 1 and 6 months (91.26% [cohort A] vs 96.43% [cohort B], OR 0.39, 95% CI 0.14-1.07, p = 0.067; 89.90% [cohort A] vs 91.55% [cohort B], OR 0.82, 95% CI 0.39-1.73, p = 0.605) were noted between the two cohorts. Postoperatively, patients in cohort A had more frequent parenchymal brain tissue injuries (2.8% vs 0%, p = 0.041). Postoperative absolute and relative hematoma reduction was similar irrespective of the location of the drain. CONCLUSIONS Subgaleal rather than subdural placement of the drain did not increase the risk for reoperation for recurrence of CSHs, nor did it have a negative impact on clinical or radiological outcome. The intention to place a subdural drain was associated with a higher rate of parenchymal injuries

Natural history of meningiomas: a serial volumetric analysis of 240 tumors.

OBJECTIVE The management of asymptomatic intracranial meningiomas is controversial. Through the assessment of growth predictors, the authors aimed to create the basis for practicable clinical pathways for the management of these tumors. METHODS The authors volumetrically analyzed meningiomas radiologically diagnosed at their institution between 2003 and 2015. The primary endpoint was growth of tumor volume. The authors used significant variables from the multivariable regression model to construct a decision tree based on the exhaustive Chi-Square Automatic Interaction Detection (CHAID) algorithm. RESULTS Of 240 meningiomas, 159 (66.3%) demonstrated growth during a mean observation period of 46.9 months. On multivariable logistic regression analysis, older age (OR 0.979 [95% CI 0.958-1.000], p = 0.048) and presence of calcification (OR 0.442 [95% CI 0.224-0.872], p = 0.019) had a negative predictive value for tumor growth, while T2-signal iso-/hyperintensity (OR 4.415 [95% CI 2.056-9.479], p < 0.001) had a positive predictive value. A decision tree model yielded three growth risk groups based on T2 signal intensity and presence of calcifications. The median tumor volume doubling time (Td) was 185.7 months in the low-risk, 100.1 months in the intermediate-risk, and 51.7 months in the high-risk group (p < 0.001). Whereas 0% of meningiomas in the low- and intermediate-risk groups had a Td of ≤ 12 months, the percentage was 8.9% in the high-risk group (p = 0.021). CONCLUSIONS Most meningiomas demonstrated growth during follow-up. The absence of calcifications and iso-/hyperintensity on T2-weighted imaging offer a practical way of stratifying meningiomas as low, intermediate, or high risk. Small tumors in the low- or intermediate-risk categories can be monitored with longer follow-up intervals