Risk Variants Associated With Normal Pressure Hydrocephalus: Genome-Wide Association Study in the FinnGen Cohort.

BACKGROUND AND OBJECTIVES: Large-scale genome-wide studies of chronic hydrocephalus have been lacking. We conducted a genome-wide association study (GWAS) in normal pressure hydrocephalus (NPH). METHODS: We used a case-control study design implementing FinnGen data containing 473,691 Finns with genotypes and nationwide health records. Patients with NPH were selected based on ICD-10 G91.2 diagnosis. To select patients with idiopathic NPH (iNPH) for sensitivity analysis, we excluded patients with a potentially known etiology of the condition using an algorithm on their disease history. The controls were the remaining non-hydrocephalic participants. For a replication analysis, the NPH cohort from UK Biobank (UKBB) was used. RESULTS: We included 1,522 patients with NPH (mean age 72.2 years, 53% women) and 451,091 controls (mean age 60.5 years, 44% women). In the GWAS comparing patients with NPH with the controls, we identified 6 gene regions significantly (p < 5.0e-8) associated with NPH that replicated in a meta-analysis with UKBB (NPH n = 173). The top loci near the following genes were rs7962263, SLCO1A2 (odds ratio [OR] 0.71, 95% CI 0.65-0.78, p = 1.0e-14); rs798495, AMZ1/GNA12 (OR 1.29, 95% CI 1.20-1.39, p = 2.9e-12); rs10828247, MLLT10 (OR 0.77, 95% CI 0.71-0.83, p = 1.5e-11); rs561699566 and rs371919113, CDCA2 (OR 0.76, 95% CI 0.70-0.82, p = 1.5e-11); rs56023709, C16orf95 (OR 1.24, 95% CI 1.16-1.33, p = 3.0e-9); and rs62434144, PLEKHG1 (OR 1.23, 95% CI 1.14-1.32, p = 1.4e-8). In the sensitivity analysis comparing only patients with iNPH (n = 1,055) with the controls (n = 451,091), 4 top loci near the following genes remained significant: rs7962263, SLCO1A2 (OR 0.70, 95% CI 0.63-0.78, p = 2.1e-11); rs10828247, MLLT10 (OR 0.74, 95% CI 0.62-0.82, p = 4.6e-10); rs798511, AMZ1/GNA12 (OR 1.28, 95% CI 1.17-1.39, p = 1.7e-8); and rs56023709, C16orf95 (OR 1.28, 95% CI 1.17-1.39, p = 1.7e-8). DISCUSSION: We identified 6 loci significantly associated with NPH in the thus far largest GWAS in chronic hydrocephalus. The genes near the top loci have previously been associated with blood-brain barrier and blood-CSF barrier function and with increased lateral brain ventricle volume. The effect sizes and allele frequencies remained similar in NPH and iNPH cohorts, indicating the identified loci are risk determinants for iNPH and likely not explained by associations with other etiologies. However, the exact role of these loci is still unknown, warranting further studies.

Diabetes is associated with familial idiopathic normal pressure hydrocephalus: a case-control comparison with family members.

BACKGROUND: The pathophysiological basis of idiopathic normal pressure hydrocephalus (iNPH) is still unclear. Previous studies have shown a familial aggregation and a potential heritability when it comes to iNPH. Our aim was to conduct a novel case-controlled comparison between familial iNPH (fNPH) patients and their elderly relatives, involving multiple different families. METHODS: Questionnaires and phone interviews were used for collecting the data and categorising the iNPH patients into the familial (fNPH) and the sporadic groups. Identical questionnaires were sent to the relatives of the potential fNPH patients. Venous blood samples were collected for genetic studies. The disease histories of the probable fNPH patients (n = 60) were compared with their ≥ 60-year-old relatives with no iNPH (n = 49). A modified Charlson Comorbidity Index (CCI) was used to measure the overall disease burden. Fisher's exact test (two-tailed), the Mann-Whitney U test (two-tailed) and a multivariate binary logistic regression analysis were used to perform the statistical analyses. RESULTS: Diabetes (32% vs. 14%, p = 0.043), arterial hypertension (65.0% vs. 43%, p = 0.033), cardiac insufficiency (16% vs. 2%, p = 0.020) and depressive symptoms (32% vs. 8%, p = 0.004) were overrepresented among the probable fNPH patients compared to their non-iNPH relatives. In the age-adjusted multivariate logistic regression analysis, diabetes remained independently associated with fNPH (OR = 3.8, 95% CI 1.1-12.9, p = 0.030). CONCLUSIONS: Diabetes is associated with fNPH and a possible risk factor for fNPH. Diabetes could contribute to the pathogenesis of iNPH/fNPH, which motivates to further prospective and gene-environmental studies to decipher the disease modelling of iNPH/fNPH.

A comparison of indirect and direct targeted STN DBS in the treatment of Parkinson's disease-surgical method and clinical outcome over 15-year timespan.

BACKGROUND: Deep brain stimulation (DBS) in the subthalamic nucleus (STN) is used in advanced Parkinson's disease (PD) for reducing motor fluctuations and the side effects of antiparkinsonian medication (APM). The development of neuroimaging has enabled the direct targeting of the STN. The aim of this study is to evaluate the outcome in patients with PD using STN DBS when changing from atlas-based indirect targeting method (iTM) to direct MRI-based targeting (dTM) assuming dTM is superior. METHODS: Twenty-five consecutive PD patients underwent dTM STN DBS surgery from 2014 to 2017 with follow-up for 1 year. The neuroimaging, surgical method, outcome in Unified Parkinson's Disease Rating Scale (UPDRS) scores, and reduction of APM are described and compared with the results of an earlier iTM STN DBS study. RESULTS: Twelve months after a dTM STN DBS, significant improvement (p < 0.001) was seen in six out of seven parameters of UPDRS when patients had medication (medON) and stimulation (stimON). The activities of daily living (UPDRSII) and motor scores (UPDRSIII) improved by 41% and 62%, respectively. Dyskinesias and fluctuations were both reduced by 81%. In dTM STN DBS group, the levodopa equivalent dose (LED) and the total daily levodopa equivalent dose (LEDD) were significantly decreased by 62% and 55%, respectively, compared with the baseline (p < 0.001). Five patients (20%) were without levodopa medication 12 months after the operation. CONCLUSIONS: The development of surgical technique based on advanced neuroimaging has improved the outcome of PD STN DBS.

Copy number loss in SFMBT1 is common among Finnish and Norwegian patients with iNPH.

OBJECTIVE: To evaluate the role of the copy number loss in SFMBT1 in a Caucasian population. METHODS: Five hundred sixty-seven Finnish and 377 Norwegian patients with idiopathic normal pressure hydrocephalus (iNPH) were genotyped and compared with 508 Finnish elderly, neurologically healthy controls. The copy number loss in intron 2 of SFMBT1 was determined using quantitative PCR. RESULTS: The copy number loss in intron 2 of SFMBT1 was detected in 10% of Finnish (odds ratio [OR] = 1.9, p = 0.0078) and in 21% of Norwegian (OR = 4.7, p < 0.0001) patients with iNPH compared with 5.4% in Finnish controls. No copy number gains in SFMBT1 were detected in patients with iNPH or healthy controls. The carrier status did not provide any prognostic value for the effect of shunt surgery in either population. Moreover, no difference was detected in the prevalence of hypertension or T2DM between SFMBT1 copy number loss carriers and noncarriers. CONCLUSIONS: This is the largest and the first multinational study reporting the increased prevalence of the copy number loss in intron 2 of SFMBT1 among patients with iNPH, providing further evidence of its role in iNPH. The pathogenic role still remains unclear, requiring further study.

Method Modification to Extend the Matrix Claim of the Thermo Scientific RapidFinder Salmonella species, Typhimurium, and Enteritidis Multiplex PCR Kit.

Background: The Thermo Scientific RapidFinder™ Salmonella species, Typhimurium and Enteritidis Multiplex PCR Kit is a real-time multiplex PCR assay for the detection and differentiation of Salmonella species, Salmonella Typhimurium, and S. Enteritidis from poultry, pork, and environmental samples. The method has previously been granted certification as Performance Tested Method SM (PTM) 081701, validated according to the AOAC Research Institute (RI) PTM program for poultry (chicken thighs with skin, chicken wings with skin, and chicken nuggets), raw pork sausage matrixes, and stainless steel environmental surface sponges. Objective: This report details the method modification study to validate ground turkey (375 g sample size), chicken carcass rinse, and shell egg matrixes. Methods: The candidate method was compared with the U.S. Food and Drug Administration's Bacteriological Analytical Manual Chapter 5 for shell eggs and the U.S. Department of Agriculture Food Safety and Inspection Service's Microbiology Laboratory Guidebook 4.09 for ground turkey (375 g) and chicken carcass rinse matrixes. Results: The statistically significant differences found between the candidate and reference methods upon analysis by probability of detection were in favor of the candidate method. Inclusivity and exclusivity testing demonstrated that the RapidFinder Salmonella species, Typhimurium and Enteritidis Multiplex PCR Kit was able to detect all the major groups of Salmonella. All exclusivity isolates were correctly excluded. Conclusions: The data presented in this report show that the candidate is suitable for the detection and differentiation of Salmonellae from shell egg, chicken carcass rinse, and ground turkey (375 g) matrixes. Highlights: Thermo Scientific RapidFinder Salmonella species, Typhimurium and Enteritidis Multiplex PCR Kit (candidate method) matrix claims extended to include ground turkey (375 g), chicken carcass rinse and shell egg samples.

Familial idiopathic normal pressure hydrocephalus.

Idiopathic normal pressure hydrocephalus (iNPH) is a late-onset surgically alleviated, progressive disease. We characterize a potential familial subgroup of iNPH in a nation-wide Finnish cohort of 375 shunt-operated iNPH-patients. The patients were questionnaired and phone-interviewed, whether they have relatives with either diagnosed iNPH or disease-related symptomatology. Then pedigrees of all families with more than one iNPH-case were drawn. Eighteen patients (4.8%) from 12 separate pedigrees had at least one shunt-operated relative whereas 42 patients (11%) had relatives with two or more triad symptoms. According to multivariate logistic regression analysis, familial iNPH-patients had up to 3-fold risk of clinical dementia compared to sporadic iNPH patients. This risk was independent from diagnosed Alzheimer's disease and APOE ε4 genotype. This study describes a familial entity of iNPH offering a novel approach to discover the potential genetic characteristics of iNPH. Discovered pedigrees offer an intriguing opportunity to conduct longitudinal studies targeting potential preclinical signs of iNPH.

Method Modification Study for the Thermo Scientific SureTect™ Listeria Species Assay-Matrix Extension.

The Thermo Scientific™ SureTect™ Listeria species assay is a new real-time PCR assay for the detection of all species of Listeria in food and environmental samples. The assay was originally certified as Performance Tested Methods(SM) (PTM) 071304 in 2013. This report details the method modification study undertaken to extend the performance claims of the assay for matrixes of raw ground turkey, raw ground pork, bagged lettuce, raw pork sausages, pasteurized 2% fat milk, raw cod, pasteurized brie cheese, and ice cream. The method modification study was conducted using the AOAC Research Institute (RI) PTM program to validate the SureTect PCR assay in comparison to the reference method detailed in ISO 11290-1:1996 including amendment 1:2004. All matrixes were tested by Thermo Fisher Scientific (Basingstoke, United Kingdom). In addition, three matrixes (raw cod, bagged lettuce, and pasteurized brie cheese) were analyzed independently as part of the AOAC RI-controlled independent laboratory study by the University of Guelph, Canada. Using probability of detection statistical analysis, there was no significant difference in the performance between the SureTect assay and the International Organization for Standardization reference method for any of the matrixes analyzed in this study.

[Update on Current Care Guideline: Parkinson's disease]. / Parkinsonin tauti.

The treatment of Parkinson's disease may be initiated with dopamine agonist or MAO-B-inhibitor for people under 60-65 years of age. For older patients, the treatment may also be started with levodopa. If there are motor complications, such as on-off-symptoms, apomorphin injections can be beneficial in addition to other medications. In the case of difficult on-off-symptoms and dyskinesias in spite of optimal treatment, deep brain stimulation, duodenal levodopa infusion and apomorphine infusion should be considered. Rehabilitation can improve gait speed and balance, decrease falls and improve speech. However, with advancing disease the results are not maintained if trainino is discontinued.

Validation of the Thermo Scientific SureTect Escherichia coli O157:H7 Real-Time PCR Assay for Raw Beef and Produce Matrixes.

The Thermo Scientific™ SureTect™ Escherichia coli O157:H7 Assay is a new real-time PCR assay which has been validated through the AOAC Research Institute (RI) Performance Tested Methods(SM) program for raw beef and produce matrixes. This validation study specifically validated the assay with 375 g 1:4 and 1:5 ratios of raw ground beef and raw beef trim in comparison to the U.S. Department of Agriculture, Food Safety Inspection Service, Microbiology Laboratory Guidebook (USDS-FSIS/MLG) reference method and 25 g bagged spinach and fresh apple juice at a ratio of 1:10, in comparison to the reference method detailed in the International Organization for Standardization 16654:2001 reference method. For raw beef matrixes, the validation of both 1:4 and 1:5 allows user flexibility with the enrichment protocol, although which of these two ratios chosen by the laboratory should be based on specific test requirements. All matrixes were analyzed by Thermo Fisher Scientific, Microbiology Division, Vantaa, Finland, and Q Laboratories Inc, Cincinnati, Ohio, in the method developer study. Two of the matrixes (raw ground beef at both 1:4 and 1:5 ratios) and bagged spinach were additionally analyzed in the AOAC-RI controlled independent laboratory study, which was conducted by Marshfield Food Safety, Marshfield, Wisconsin. Using probability of detection statistical analysis, no significant difference was demonstrated by the SureTect kit in comparison to the USDA FSIS reference method for raw beef matrixes, or with the ISO reference method for matrixes of bagged spinach and apple juice. Inclusivity and exclusivity testing was conducted with 58 E. coli O157:H7 and 54 non-E. coli O157:H7 isolates, respectively, which demonstrated that the SureTect assay was able to detect all isolates of E. coli O157:H7 analyzed. In addition, all but one of the nontarget isolates were correctly interpreted as negative by the SureTect Software. The single isolate giving a positive result was an E. coli O157:NM isolate. Nonmotile isolates of E. coli O157 have been demonstrated to still contain the H7 gene; therefore, this result is not unexpected. Robustness testing was conducted to evaluate the performance of the SureTect assay with specific deviations to the assay protocol, which were outside the recommended parameters and which are open to variation. This study demonstrated that the SureTect assay gave reliable performance. A final study to verify the shelf life of the product, under accelerated conditions was also conducted.

Method Modification of the Thermo Scientific SureTect Listeria monocytogenes Assay for Raw Meat, Dairy, Produce, and Seafood.

The Thermo Scientific™ SureTect™ Listeria monocytogenes assay is a real-time PCR assay for the detection of Listeria monocytogenes in food and environmental samples, which was certified during 2013 by the AOAC Research Institute (RI) as Performance Tested Method(SM) (PTM) 061302 for a representative range of key food matrixes and production surfaces. This report details the method modification study, which was conducted during 2014, using the AOAC-RI PTM program to extend the validated matrix claims of the assay in comparison to the reference method detailed in International Organization for Standardization 11290-1:1996, including Amendment 1:2004, to gain certification for raw ground turkey, raw ground pork, pasteurized 2% milk, raw pork sausages, raw cod, pasteurized brie cheese, cooked sliced ham, and bagged lettuce. All matrixes were tested by Thermo Fisher Scientific, Microbiology Division, Basingstoke, UK. In addition, brie cheese, bagged lettuce, and raw cod were analyzed independently by the University of Guelph, Canada, during the AOAC-RI controlled independent laboratory study. Using probability of detection (POD) statistical analysis, a significant difference was demonstrated between the candidate and reference methods for the high spiking level with raw ground pork and brie cheese. For all other matrixes and the low spiked levels for raw ground pork and brie cheese, no significant difference by POD was seen between the two methods during the study.

Evaluation of the Thermo Scientific SureTect Salmonella species assay. AOAC Performance Tested Method 051303.

The Thermo Scientific SureTect Salmonella species Assay is a new real-time PCR assay for the detection of Salmonellae in food and environmental samples. This validation study was conducted using the AOAC Research Institute (RI) Performance Tested Methods program to validate the SureTect Salmonella species Assay in comparison to the reference method detailed in International Organization for Standardization 6579:2002 in a variety of food matrixes, namely, raw ground beef, raw chicken breast, raw ground pork, fresh bagged lettuce, pork frankfurters, nonfat dried milk powder, cooked peeled shrimp, pasteurized liquid whole egg, ready-to-eat meal containing beef, and stainless steel surface samples. With the exception of liquid whole egg and fresh bagged lettuce, which were tested in-house, all matrixes were tested by Marshfield Food Safety, Marshfield, WI, on behalf of Thermo Fisher Scientific. In addition, three matrixes (pork frankfurters, lettuce, and stainless steel surface samples) were analyzed independently as part of the AOAC-RI-controlled laboratory study by the University of Guelph, Canada. No significant difference by probability of detection or McNemars Chi-squared statistical analysis was found between the candidate or reference methods for any of the food matrixes or environmental surface samples tested during the validation study. Inclusivity and exclusivity testing was conducted with 117 and 36 isolates, respectively, which demonstrated that the SureTect Salmonella species Assay was able to detect all the major groups of Salmonella enterica subspecies enterica (e.g., Typhimurium) and the less common subspecies of S. enterica (e.g., arizoniae) and the rarely encountered S. bongori. None of the exclusivity isolates analyzed were detected by the SureTect Salmonella species Assay. Ruggedness testing was conducted to evaluate the performance of the assay with specific method deviations outside of the recommended parameters open to variation (enrichment time and temperature, and lysis temperature), which demonstrated that the assay gave reliable performance. Accelerated stability testing was additionally conducted, validating the assay shelf life.

Evaluation of the Thermo Scientific SureTect Listeria species assay. AOAC Performance Tested Method 071304.

The Thermo Scientific SureTect Listeria species Assay is a new real-time PCR assay for the detection of all species of Listeria in food and environmental samples. This validation study was conducted using the AOAC Research Institute (RI) Performance Tested Methods program to validate the SureTect Listeria species Assay in comparison to the reference method detailed in International Organization for Standardization 11290-1:1996 including amendment 1:2004 in a variety of foods plus plastic and stainless steel. The food matrixes validated were smoked salmon, processed cheese, fresh bagged spinach, cantaloupe, cooked prawns, cooked sliced turkey meat, cooked sliced ham, salami, pork frankfurters, and raw ground beef. All matrixes were tested by Thermo Fisher Scientific, Microbiology Division, Basingstoke, UK. In addition, three matrixes (pork frankfurters, fresh bagged spinach, and stainless steel surface samples) were analyzed independently as part of the AOAC-RI-controlled independent laboratory study by the University ofGuelph, Canada. Using probability of detection statistical analysis, a significant difference in favour of the SureTect assay was demonstrated between the SureTect and reference method for high level spiked samples of pork frankfurters, smoked salmon, cooked prawns, stainless steel, and low-spiked samples of salami. For all other matrixes, no significant difference was seen between the two methods during the study. Inclusivity testing was conducted with 68 different isolates of Listeria species, all of which were detected by the SureTect Listeria species Assay. None of the 33 exclusivity isolates were detected by the SureTect Listeria species Assay. Ruggedness testing was conducted to evaluate the performance of the assay with specific method deviations outside of the recommended parameters open to variation, which demonstrated that the assay gave reliable performance. Accelerated stability testing was additionally conducted, validating the assay shelf life.

Evaluation of the Thermo Scientific SureTect Listeria monocytogenes Assay.

The Thermo Scientific SureTect Listeria monocytogenes Assay is a new real-time PCR assay for the detection of Listeria monocytogenes in food and environmental samples. This assay was validated using the AOAC Research Institute (AOAC-RI) Performance Tested Methods program in comparison to the reference method detailed in International Organization for Standardization 11290-1:1996, including Amendment 1:2004 with the following foods and food contact surfaces: smoked salmon, processed cheese, fresh bagged spinach, fresh cantaloupe, cooked prawns (chilled product), cooked sliced turkey meat (chilled product), ice cream, pork frankfurters, salami, ground raw beef meat (12% fat), plastic, and stainless steel. All matrixes were tested by Thermo Fisher Scientific, Microbiology Division, Basingstoke, UK. In addition, three matrixes (pork frankfurters, bagged lettuce, and stainless steel) were analyzed independently as part of the AOAC-RI controlled laboratory study by the University of Guelph, Canada. Using probability of detection (POD) statistical analysis, a significant difference was demonstrated between the candidate and reference methods for salami, cooked sliced turkey and ice cream in favor of the SureTect assay. For all other matrixes, no significant difference by POD was seen between the two methods during the study. Inclusivity and exclusivity testing was also conducted with 53 and 30 isolates, respectively, which demonstrated that the SureTect assay was able to detect all serotypes of L. monocytogenes. None of the exclusivity isolates analyzed were detected by the SureTect assay. Ruggedness testing was conducted to evaluate the performance of the assay with specific method deviations outside the recommended parameters open to variation, i.e., enrichment time and temperature and lysis temperature, which demonstrated that the assay gave reliable performance. Accelerated stability testing was also conducted, validating the assay shelf life.

Evaluation of the Thermo Scientific™ SureTect™ Listeria species Assay.

The Thermo Scientific™ SureTect™ Listeria species Assay is a new real-time PCR assay for the detection of all species of Listeria in food and environmental samples. This validation study was conducted using the AOAC Research Institute (RI) Performance Tested MethodsSM program to validate the SureTect Listeria species Assay in comparison to the reference method detailed in International Organization for Standardization 11290-1:1996 including amendment 1:2004 in a variety of foods plus plastic and stainless steel. The food matrixes validated were smoked salmon, processed cheese, fresh bagged spinach, cantaloupe, cooked prawns, cooked sliced turkey meat, cooked sliced ham, salami, pork frankfurters, and raw ground beef. All matrixes were tested by Thermo Fisher Scientific, Microbiology Division, Basingstoke, UK. In addition, three matrixes (pork frankfurters, fresh bagged spinach, and stainless steel surface samples) were analyzed independently as part of the AOAC-RI-controlled independent laboratory study by the University of Guelph, Canada. Using probability of detection statistical analysis, a significant difference in favour of the SureTect assay was demonstrated between the SureTect and reference method for high level spiked samples of pork frankfurters, smoked salmon, cooked prawns, stainless steel, and low-spiked samples of salami. For all other matrixes, no significant difference was seen between the two methods during the study. Inclusivity testing was conducted with 68 different isolates of Listeria species, all of which were detected by the SureTect Listeria species Assay. None of the 33 exclusivity isolates were detected by the SureTect Listeria species Assay. Ruggedness testing was conducted to evaluate the performance of the assay with specific method deviations outside of the recommended parameters open to variation, which demonstrated that the assay gave reliable performance. Accelerated stability testing was additionally conducted, validating the assay shelf life.

Evaluation of the Thermo Scientific™ SureTect™ Salmonella species Assay.

The Thermo Scientific™ SureTect™ Salmonella species Assay is a new real-time PCR assay for the detection of Salmonellae in food and environmental samples. This validation study was conducted using the AOAC Research Institute (RI) Performance Tested MethodsSM program to validate the SureTect Salmonella species Assay in comparison to the reference method detailed in International Organization for Standardization 6579:2002 in a variety of food matrixes, namely, raw ground beef, raw chicken breast, raw ground pork, fresh bagged lettuce, pork frankfurters, nonfat dried milk powder, cooked peeled shrimp, pasteurized liquid whole egg, ready-to-eat meal containing beef, and stainless steel surface samples. With the exception of liquid whole egg and fresh bagged lettuce, which were tested in-house, all matrixes were tested by Marshfield Food Safety, Marshfield, WI, on behalf of Thermo Fisher Scientific. In addition, three matrixes (pork frankfurters, lettuce, and stainless steel surface samples) were analyzed independently as part of the AOAC-RI-controlled laboratory study by the University of Guelph, Canada. No significant difference by probability of detection or McNemars Chi-squared statistical analysis was found between the candidate or reference methods for any of the food matrixes or environmental surface samples tested during the validation study. Inclusivity and exclusivity testing was conducted with 117 and 36 isolates, respectively, which demonstrated that the SureTect Salmonella species Assay was able to detect all the major groups of Salmonella enterica subspecies enterica (e.g., Typhimurium) and the less common subspecies of S. enterica (e.g., arizoniae) and the rarely encountered S. bongori. None of the exclusivity isolates analyzed were detected by the SureTect Salmonella species Assay. Ruggedness testing was conducted to evaluate the performance of the assay with specific method deviations outside of the recommended parameters open to variation (enrichment time and temperature, and lysis temperature), which demonstrated that the assay gave reliable performance. Accelerated stability testing was additionally conducted, validating the assay shelf life.

Stereotactic operations using the o-arm.

BACKGROUND: In stereotactic operations, intraoperative imaging is crucial in several stages of the procedure. The aim was to utilize the O-arm intraoperatively for (1) planning the trajectories of stereotactic instruments, (2) calculating the coordinates of the targets, (3) identification of normal intracranial structures, (4) verification of the trajectories of the stereotactic instruments, and (5) visualization of intracranial hematoma. This is the first study using the O-arm for calculations of the target coordinates in frame-based stereotaxy. METHODS: Utilization of the O-arm as a full-scale intraoperative imaging system in stereotactic surgery required a new concept. The concept consists of the O-arm as an intraoperative imaging system and the Leksell stereotactic system with a modified CT coordinate indicator box, with the idea to widen limited imaging volume. The accuracy and feasibility of the concept were studied. RESULTS: The use of O-arm imaging was found to be clinically feasible, enabling the achievement of adequate technical accuracy for stereotactic operations with submillimeter errors in the calculation of target coordinates, and for multiple intraoperative control images when required. CONCLUSIONS: The O-arm could be used alone, with high accuracy, as an intraoperative imaging system for planning and controlling in stereotactic operations. In addition, it can be used to exclude serious complications, especially intracerebral hematoma.