Robotic stereotactic radiosurgery for intracranial meningiomas in elderly patients: assessment of treatment efficacy and safety.

Purpose: Stereotactic radiosurgery (SRS) has been increasingly used to treat intracranial pathologies in elderly patients. The treatment efficiency of SRS has been demonstrated in meningiomas, with excellent local control. We aimed to analyze the safety of robotic SRS in elderly patients with meningiomas. Methods: We searched for patients with suspected WHO °I meningioma ≥ 60 years old, who underwent CyberKnife (CK) SRS from January 2011 to December 2021. Tumor localization was categorized using the "CLASS" algorithmic scale. Tumor response was evaluated using the Response Assessment in Neuro-Oncology (RANO) criteria for meningiomas. Adverse effects were graded using the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 and a cox regression was performed to investigate possible predictors. Results: We identified 82 patients with 102 CK-treated lesions that matched the criteria for the first SRS. The median age was 70 [IQR 64-75] years, and 24.3% of the patients were aged > 75 years. Multiple lesions (up to six) were treated in 14.1% of the SRS-sessions. A previous surgery was performed in 57.3% of lesions, with a median time interval of 41 [IQR 10 - 58] months between the initial surgical procedure and the SRS treatment. In 47.9% of cases, CLASS 3 meningiomas at high-risk locations were irradiated. Single fraction radiosurgery was applied to 62.5% of the lesions, while in the remaining cases multi-session SRS with three to five fractions was used. During the median follow-up period of 15.9 months, lesion size progression was observed in 3 cases. Karnofsky Performance Status (KPS) declined by ≥ 20 points in four patients. Adverse effects occurred in 13 patients, while only four patients had CTCAE ≥2 toxicities. Hereby only one of these toxicities was persistent. The occurrence of complications was independent of age, planned target volume (PTV), high-risk localization, and surgery before SRS. Conclusion: The data indicates that SRS is a safe, efficient, and convenient treatment modality for elderly patients with meningioma, even at high-risk locations.

The Use of Intraoperative CT Hounsfield Unit Values for the Assessment of Bone Quality in Patients Undergoing Lumbar Interbody Fusion.

STUDY DESIGN: Retrospective Cohort Study. OBJECTIVE: To evaluate the accuracy of intraoperatively measured computed tomography (CT) Hounsfield unit (HU) values by comparison with preoperative CT HU values and to compare the radiation exposure between preoperative and intraoperative CT scans. METHODS: HU values of lumbar vertebrae were measured and compared between preoperative and intraoperative CT scans in patients undergoing lumbar interbody fusion. In patient group one, Canon CT scanners were used preoperatively and the AIRO CT scanner was used intraoperatively. In patient group two, Canon CT scanners were used preoperatively and the O-arm Cone Beam CT (CBCT) scanner was used intraoperatively. In a subgroup analysis of patient group one, radiation by means of CT Dose Index (CTDI) was compared between Canon and AIRO CT scanners. RESULTS: In the first patient group, a total of 250 vertebrae were analysed in 74 patients showing a strong Pearson correlation of >.94 between pre- and intraoperative HU values. Bland-Altman analysis indicated consistency and equivalence with a bias of 3.9 and 95% limits of agreement from -27.17 to 34.97 when comparing all pre- and intraoperative HU values of L1-5. In the second patient group, a total of 27 vertebrae were analysed in 10 patients showing weak Pearson correlation and Bland-Altman analysis indicated no equivalence. CTDI did not differ between Canon and AIRO CT scanners. CONCLUSION: Correct and reliable CT HU measurement as mandatory key factor for the intraoperative assessment of bone quality and robotic-assisted surgery is feasible with intraoperative AIRO CT imaging without increase of radiation exposure.

MRI-Based Risk Assessment for Incomplete Resection of Brain Metastases.

Object: Recent studies demonstrated that gross total resection of brain metastases cannot always be achieved. Subtotal resection (STR) can result in an early recurrence and might affect patient survival. We initiated a prospective observational study to establish a MRI-based risk assessment for incomplete resection of brain metastases. Methods: All patients in whom ≥1 brain metastasis was resected were prospectively included in this study (DRKS ID: DRKS00021224; Nov 2020 - Nov 2021). An interdisciplinary board of neurosurgeons and neuroradiologists evaluated the pre- and postoperative MRI (≤48h after surgery) for residual tumor. Extensive neuroradiological analyses were performed to identify risk factors for an unintended STR which were integrated into a regression tree analysis to determine the patients' individual risk for a STR. Results: We included 150 patients (74 female; mean age: 61 years), in whom 165 brain metastases were resected. A STR was detected in 32 cases (19.4%) (median residual tumor volume: 1.36ml, median EORrel: 93.6%), of which 6 (3.6%) were intended STR (median residual tumor volume: 3.27ml, median EORrel: 67.3%) - mainly due to motor-eloquent location - and 26 (15.8%) were unintended STR (uSTR) (median residual tumor volume: 0.64ml, median EORrel: 94.7%). The following risk factors for an uSTR could be identified: subcortical metastasis ≥5mm distant from cortex, diffuse contrast agent enhancement, proximity to the ventricles, contact to falx/tentorium and non-transcortical approaches. Regression tree analysis revealed that the individual risk for an uSTR was mainly associated to the distance from the cortex (distance ≥5mm vs. <5mm: OR 8.0; 95%CI: 2.7 - 24.4) and the contrast agent patterns (diffuse vs. non-diffuse in those with distance ≥5mm: OR: 4.2; 95%CI: 1.3 - 13.7). The preoperative tumor volume was not substantially associated with the extent of resection. Conclusions: Subcortical metastases ≥5mm distant from cortex with diffuse contrast agent enhancement showed the highest incidence of uSTR. The proposed MRI-based assessment allows estimation of the individual risk for uSTR and can help indicating intraoperative imaging.

Eloquent Lower Grade Gliomas, a Highly Vulnerable Cohort: Assessment of Patients' Functional Outcome After Surgery Based on the LoG-Glio Registry.

Majority of lower grade glioma (LGG) are located eloquently rendering surgical resection challenging. Aim of our study was to assess rate of permanent deficits and its predisposing risk factors. We retrieved 83 patients harboring an eloquently located LGGs from the prospective LoG-Glio Database. Patients without surgery or incomplete postoperative data were excluded. Sign rank test, explorative correlations by Spearman ρ and multivariable regression for new postoperative deficits were calculated. Eloquent region involved predominantly motor (45%) and language (40%). At first follow up after 3 months permanent neuro-logical deficits (NDs) were noted in 39%. Mild deficits remained in 29% and severe deficits in 10%. Complete tumor removal (CTR) was successfully in 62% of intended cases. Postoperative and 3-month follow up National Institute of Health Stroke Score (NIHSS) showed significantly lower values than preoperatively (p<0.001). 38% cases showed a decreased NIHSS at 3-month, while occurrence was only 14% at 9-12-month follow up. 6/7 patients with mild aphasia recovered after 9-12 months, while motor deficits present at 3-month follow up were persistent in majority of patients. Eastern oncology group functional status (ECOG) significantly decreased by surgery (p < 0.001) in 31% of cases. Between 3-month and 9-12-months follow up no significant improvement was seen. In the multivariable model CTR (p=0.019, OR 31.9), and ECOG>0 (p=0.021, OR 8.5) were independent predictors for permanent postoperative deficit according to NIHSS at 3-month according to multivariable regression model. Patients harboring eloquently located LGG are highly vulnerable for permanent deficits. Almost one third of patients have a permanent reduction of their functional status based on ECOG. Risk of an extended resection has to be balanced with the respective oncological benefit. Especially, patients with impaired pre-operative status are at risk for new permanent deficits. There is a relevant improvement of neurological symptoms in the first year after surgery, especially for patients with slight aphasia.

Navigated percutaneous versus open pedicle screw implantation using intraoperative CT and robotic cone-beam CT imaging.

PURPOSE: Percutaneous paraspinal pedicle screw implantation (PPSI) reduces soft tissue trauma, blood loss, and postoperative pain but remains technically challenging and associated with radiation exposure and implant-related artefacts. Here, we determined the feasibility, screw accessibility, and the accuracy of navigated PPSI in the thoraco-lumbar sacral spine using intraoperative computed tomography (iCT) and robotic cone-beam CT (CBCT) imaging. METHODS: Between 2015 and 2018, 465 percutaneous paraspinal pedicle screws were implanted in 75 patients using iCT- or CBCT-based spinal navigation with 230 screws connected to rod reducers during screw assessment imaging (iCT 198; CBCT 32). Clinical and demographic data, intraoperative screw accessibility, and screw accuracy were analyzed and compared to a case-matched cohort of 75 patients undergoing navigated implantation of 481 pedicle screws through an open midline approach. RESULTS: Both iCT and CBCT permitted reliable assessment of each implanted screw, regardless of artifacts caused by rod reducers. Although overall accuracy for correct placement was comparable between PPSI and open surgery (PPSI 96.6%; Open 94.2%), PPSI compared favorably to open surgery regarding complete placement within the pedicle (PPSI 90.1%; Open 75.1%; p < 0.0001), regional placement accuracy in the lumbar (PPSI 97.8%; Open 91.5%; p < 0.001), and lumbar-sacral spine (PPSI 100%; Open 81.2%; p < 0.05), next to the duration of surgery and length of hospitalization. CONCLUSIONS: PPSI with iCT- and CBCT-based spinal navigation improves the accuracy, safety, and workflow of navigated spinal instrumentation. Next, a cost-effectiveness and outcome analysis should determine whether iCT and CBCT imaging are truly economically justified. These slides can be retrieved under Electronic Supplementary Material.

Blood Flow Assessment of Arteriovenous Malformations Using Intraoperative Indocyanine Green Videoangiography.

Intraoperative indocyanine green (ICG) videoangiography is widely used in patients undergoing neurosurgery. FLOW800 is a recently developed analytical tool for ICG videoangiography to assess semi-quantitative flow dynamics; however, its efficacy is unknown. In this study, we evaluated its functionality in the assessment of flow dynamics of arteriovenous malformation (AVM) through ICG videoangiography under clinical settings. ICG videoangiography was performed in the exposed AVM in eight patients undergoing surgery. FLOW800 analysis was applied directly, and gray-scale and color-coded maps of the surgical field were obtained. After surgery, a region of interest was placed on the individual vessels to obtain time-intensity curves. Parameters of flow dynamics, including the maximum intensity, transit time, and cerebral blood flow index, were calculated using the curves. The color-coded maps provided high-resolution images; however, reconstruction of colored images was restricted by the depth, approach angle, and brain swelling. Semi-quantitative parameters were similar among the feeders, niduses, and drainers. However, a higher cerebral blood flow index was observed in the feeders of large AVM (>3 cm) than in those of small AVM (P < 0.05). Similarly, the cerebral blood flow index values were positively correlated with the nidus volume (P < 0.01). FLOW800 enabled visualization of the AVM structure and safer resection, except in case of deep-seated AVM. Moreover, semi-quantitative values in the individual vessels through using ICG intensity diagram showed different patterns according to size of the AVM. ICG videoangiography showed good performance in evaluating flow dynamics of the AVM in patients undergoing surgery.

Prospective Randomized Open-label Trial to evaluate risk faCTor management in patients with Unruptured intracranial aneurysms: Study protocol.

RATIONALE: Unruptured intracranial aneurysms are currently left untreated if the presumed complication risk of preventive endovascular or neurosurgical intervention is higher than the risk of rupture. Aneurysm wall inflammation and blood pressure are attractive modifiable risk factors of aneurysm rupture and growth. AIM: To investigate in patients with an unruptured intracranial aneurysm who do not qualify for preventive endovascular or neurosurgical intervention whether a treatment strategy of acetylsalicylic acid 100 mg/day plus intensive blood pressure treatment (targeted systolic blood pressure < 120 mmHg, monitored with a home blood pressure measuring device) reduces the risk of aneurysm rupture or growth compared with care as usual (no acetylsalicylic acid, targeted office systolic blood pressure < 140 mmHg, no home blood pressure measuring device). SAMPLE SIZE: We aim to randomize 776 patients 1:1 to the intervention arm or care as usual. DESIGN: Bi-national (Germany and the Netherlands) multicenter, prospective, randomized, open-label phase III trial with blinded outcome assessment. OUTCOMES: The primary outcome is aneurysm rupture or growth (increase in any aneurysm diameter by ≥ 1 mm) on repeated MR or CT angiography within 36 ± 6 months after randomization. DISCUSSION: The Prospective Randomized Open-label Trial to Evaluate risk faCTor management in patients with Unruptured intracranial aneurysms (PROTECT-U) is the first randomized trial to investigate if a medical strategy reduces the risk of rupture or growth of intracranial aneurysms in patients not undergoing preventive endovascular or neurosurgical aneurysm treatment. Clinical trial Registration: NCT03063541.

Fluorescein videoangiography during extracranial-to-intracranial bypass surgery: preliminary results.

BACKGROUND: Over the last years, intraoperative use of fluorescein is gaining ground in the field of neurosurgery, due to development of a microscope-integrated YELLOW 560 module, with reported experiences in brain malignancies, aneurysms, and arteriovenous malformation surgery. The aim of this study is to determine the feasibility and value of fluorescein videoangiography during bypass procedures. METHODS: The authors enrolled 11 patients who underwent extracranial-to-intracranial bypass for moyamoya disease, atherosclerotic steno-occlusive cerebrovascular disease, and flow replacement during a giant middle cerebral artery (MCA) aneurysm treatment. Patients underwent fluorescein videoangiography using microscope-integrated fluorescence module. RESULTS: In all 11 cases, good bypass patency was intraoperatively demonstrated through fluorescein videoangiography and confirmed by post-operative digital subtraction angiography or computed tomographic angiography. The technique seems to be less sensible than standard indocyanine green videoangiography in terms of flow velocity assessment during first pass and does not benefit from a dedicated software to perform hemodynamic parameter analysis (i.e., FLOW 800). Fluorescein videoangiography was able to show a higher number of vessels than indocyanine green videoangiography, providing an extremely well-defined view of cortical vascular network, also in deeper cortical areas. In case of deep-seated anastomosis, it allowed real-time manipulation of neurovascular structures, making it possible a safe analysis of vessels in deep surgical field during videoangiography observation. CONCLUSIONS: Fluorescein videoangiography is a cost-effective, easy-to-use, fast and safe intraoperative tool and is useful to assess graft patency and extent of cortical vascular network also in deeper cortical areas. In case of deep-seated anastomosis, it provides the great advantage of performing real-time manipulation of neurovascular structures during videoangiography observation. It could represent a valuable complementary or alternative technique to assess intraoperative bypass function.

Decision Making in Surgery for Nonsaccular Posterior Inferior Cerebellar Artery Aneurysms With Special Reference to Intraoperative Assessment of Collateral Blood Flow and Neurophysiological Function.

BACKGROUND: Posterior inferior cerebellar artery (PICA) aneurysms represent a challenging pathology. PICA sacrifice is often necessary, due to the high proportion of nonsaccular aneurysms that can be found in this location. Several treatments are available, but the infrequency of these aneurysms and the increasing number of endovascular techniques have limited the development of a standardized algorithm for cases in which open surgery is indicated. OBJECTIVE: We present our series of nonsaccular PICA aneurysms, in the attempt to define an algorithm for their surgical management. METHODS: We retrospectively reviewed the operation database, identifying patients harboring nonsaccular PICA aneurysms who were surgically treated at our institution from 2007 to 2016. RESULTS: During a 9-yr period, 17 patients harboring 18 nonsaccular PICA aneurysms were surgically treated at our institution. Fourteen (7.7%) aneurysms were located within the proximal PICA (including those located at the vertebral artery-PICA junction), and 4 were located distally. We performed PICA revascularization in 8 (57.1%) cases of proximal aneurysms (n = 4, PICA-PICA bypass; n = 4, occipital artery-PICA bypass). We based our decision whether to perform bypass on intraoperative test occlusion with indocyanine green (ICG) videoangiography and neurophysiological monitoring. In no cases, bypass was necessary for distal aneurysms. CONCLUSION: For nonsaccular PICA aneurysms, in which vessel occlusion is often necessary, it is possible to adopt a selective use of revascularization techniques. Intraoperative occlusion test with ICG videoangiography and neurophysiological monitoring provides reliable indications, allowing real-time assessment of collateral circulation.

Assessment of intracranial venous blood flow after subarachnoid hemorrhage: a new approach to diagnose vasospasm with transcranial color-coded duplex sonography.

OBJECTIVETranscranial color-coded duplex sonography (TCCS) is a reliable tool that is used to assess vasospasm in the M1 segment of the middle cerebral artery (MCA) after subarachnoid hemorrhage (SAH). A distinct increase in blood flow velocity (BFV) is the principal criterion for vasospasm. The MCA/internal carotid artery (ICA) index (Lindegaard Index) is also widely used to distinguish between vasospasm and cerebral hyperperfusion. However, extracranial ultrasonography assessment of the neck vessels might be difficult in an intensive care unit. Therefore, the authors evaluated whether the relationship of intracranial arterial to venous BFV might indicate vasospasm with similar or even better accuracy.METHODSPatients who presented between 2008 and 2015 with aneurysmal SAH were prospectively enrolled in the study. Digital subtraction angiography (DSA) and TCCS were performed within 24 hours of each other to assess vasospasm 8-10 days after SAH. The following different TCCS parameters were analyzed to assess vasospasm in the MCA and were compared with the gold-standard DSA parameters: 1) mean time-averaged maximum BFV (Vmean) of the MCA, 2) peak systolic velocity (PSV) of the MCA, 3) the Lindegaard Index using Vmean as well as PSV, and 4) a new arteriovenous index (AVI) between the MCA and the basal vein of Rosenthal using Vmean and PSV. The best cutoff values for these parameters to distinguish vasospasm from normal perfusion or hyperperfusion were calculated using receiver operating characteristic curve analysis. Sensitivity, specificity, positive predictive value, and negative predictive value as well as the overall accuracy for each cutoff value were analyzed.RESULTSA total of 102 patients (mean age 52 ± 12 years) were evaluated. Bilateral MCA assessment by TCCS was successful in all patients. In 6 cases (3%), the BFV of the basal vein of Rosenthal could not be analyzed. The AVI could not be calculated in 50 of 204 cases (25%) because the insonation quality was very low in one of the ICAs. An AVI > 10 for Vmean and an AVI > 12 for systolic velocity provided the highest accuracies of 87% and 86%, respectively. Regarding the Lindegaard Index, the accuracy was highest using a threshold of > 3 for the mean BFV (84%) as well as systolic BFV (80%). BFVs in the MCA of ≥ 120 cm/sec (Vmean) and ≥ 200 cm/sec (PSV) predicted vasospasm with accuracies of 84% and 83%, respectively. A combined analysis of the MCA BFV and the AVI led to a slight increase in specificity (Vmean, 94%; PSV, 93%) and positive predictive value (Vmean, 88%; PSV 86%) without further improvement in accuracy (Vmean, 88%; PSV, 84%).CONCLUSIONSThe intracranial AVI is a reliable parameter that can be used to assess vasospasm after SAH. Its reliability for differentiating vasospasm and hyperperfusion is slightly higher than that for the established Lindegaard Index, and this method has the additional advantage of a remarkably lower failure rate.

Cost Comparison of Surgical and Endovascular Treatment of Unruptured Giant Intracranial Aneurysms.

BACKGROUND: Giant intracranial aneurysms (GIAs), which are defined as intracranial aneurysms (IAs) with a diameter of ≥25 mm, are most likely associated with the highest treatment costs of all IAs. However, the treatment costs of unruptured GIAs have so far not been reported. OBJECTIVE: To examine direct costs of endovascular and surgical treatment of unruptured GIAs. METHODS: We retrospectively examined 55 patients with unruptured GIAs treated surgically (37 patients) or endovascularly (18 patients) between April 2004 and March 2014. We analyzed the costs of all hospital stays, interventions, and imaging with a median follow-up of 46 months. RESULTS: There was no difference in the costs of hospital stay between surgical and endovascular treatment groups ($10,565 vs. $14,992; P = .37). Imaging costs were significantly higher in the surgical group than in the endovascular treatment group ($2890 vs. $1612; P < .01), as were the costs of the intervention room and personnel involved in the intervention ($5566 vs. $1520; P < .01). Implants used per patient were more expensive in the endovascular group than in the surgical treatment group ($20,885 vs. $167). The total direct treatment costs were higher in the endovascular group ($52,325) than in the surgical treatment group ($20,619; P < .01). Treatment costs were associated with the type of treatment and GIA location but not with patient age, sex, or GIA size. CONCLUSION: Endovascular GIA treatment produced higher direct costs than surgical GIA treatment mainly due to higher implant costs. Reducing endovascular implant costs may be the most effective tool to decrease direct costs of GIA treatment.

Multidisciplinary consensus on assessment of unruptured intracranial aneurysms: proposal of an international research group.

BACKGROUND AND PURPOSE: To address the increasing need to counsel patients about treatment indications for unruptured intracranial aneurysms (UIA), we endeavored to develop a consensus on assessment of UIAs among a group of specialists from diverse fields involved in research and treatment of UIAs. METHODS: After composition of the research group, a Delphi consensus was initiated to identify and rate all features, which may be relevant to assess UIAs and their treatment by using ranking scales and analysis of inter-rater agreement (IRA) for each factor. IRA was categorized as very high, high, moderate, or low. RESULTS: Ultimately, 39 specialists from 4 specialties agreed (high or very high IRAs) on the following key factors for or against UIA treatment decisions: (1) patient age, life expectancy, and comorbid diseases; (2) previous subarachnoid hemorrhage from a different aneurysm, family history for UIA or subarachnoid hemorrhage, nicotine use; (3) UIA size, location, and lobulation; (4) UIA growth or de novo formation on serial imaging; (5) clinical symptoms (cranial nerve deficit, mass effect, and thromboembolic events from UIAs); and (6) risk factors for UIA treatment (patient age and life expectancy, UIA size, and estimated risk of treatment). However, IRAs for features rated with low relevance were also generally low, which underlined the existing controversy about the natural history of UIAs. CONCLUSIONS: Our results highlight that neurovascular specialists currently consider many features as important when evaluating UIAs but also highlight that the appreciation of natural history of UIAs remains uncertain, even within a group of highly informed individuals.

FLOW 800 allows visualization of hemodynamic changes after extracranial-to-intracranial bypass surgery but not assessment of quantitative perfusion or flow.

BACKGROUND: FLOW 800 delivers a color-coded map for snapshot visualization of the temporal distribution dynamics after indocyanine green angiography with post hoc calculation of FLOW 800-specific hemodynamic parameters. However, the value of these parameters regarding quantitative flow assessment remains unclear. OBJECTIVE: To determine the value of FLOW 800-specific hemodynamic parameters in neurosurgical patients that permit assessment of hemodynamic changes within the microcirculation and macrocirculation. METHODS: FLOW 800 was performed in 25 patients undergoing superficial temporal artery to middle cerebral artery bypass grafting and in 5 patients undergoing high- or intermediate-flow bypass grafting. The time to half-maximum fluorescence (t1/2max) and the cerebral blood flow index were calculated in the recipient vessel (macrocirculation) and the cortical territory (microcirculation) surrounding the anastomosis. For further evaluation, FLOW 800-specific hemodynamic parameters were compared with cortical laser speckle imaging and quantitative Doppler flow within the graft. RESULTS: FLOW 800 provided color-coded information on the temporospatial distribution dynamics of the dye with excellent assessment of bypass patency. In the recipient vessel and in the cortical territory surrounding the anastomosis, FLOW 800 detected hemodynamic changes after superficial temporal artery to middle cerebral artery bypass grafting in terms of a significant decrease in t1/2max and increase in cerebral blood flow index. Interestingly, comparison of t1/2max with semiquantitative laser speckle imaging-specific cortical perfusion within the microcirculation demonstrated poor agreement, and neither t1/2max nor the cerebral blood flow index within the graft correlated with quantitative graft flow assessed by Doppler. CONCLUSION: FLOW 800 may detect procedure-related hemodynamic changes within the microcirculation and macrocirculation but should not be used as a stand-alone tool for quantitative flow assessment.

Laser speckle imaging allows real-time intraoperative blood flow assessment during neurosurgical procedures.

Currently, there is no adequate technique for intraoperative monitoring of cerebral blood flow (CBF). To evaluate laser speckle imaging (LSI) for assessment of relative CBF, LSI was performed in 30 patients who underwent direct surgical revascularization for treatment of arteriosclerotic cerebrovascular disease (ACVD), Moyamoya disease (MMD), or giant aneurysms, and in 8 control patients who underwent intracranial surgery for reasons other than hemodynamic compromise. The applicability and sensitivity of LSI was investigated through baseline perfusion and CO2 reactivity testing. The dynamics of LSI were assessed during bypass test occlusion and flow initiation procedures. Laser speckle imaging permitted robust (pseudo-) quantitative assessment of relative microcirculatory flow and standard bypass grafting resulted in significantly higher postoperative baseline perfusion values in ACVD and MMD. The applicability and sensitivity of LSI was shown by a significantly reduced CO2 reactivity in ACVD (9.6±9%) and MMD (8.5±8%) compared with control (31.2±5%; P<0.0001). In high- and intermediate-flow bypass patients, LSI was characterized by a dynamic real-time response to acute perfusion changes and ultimately confirmed a sufficient flow substitution through the bypass graft. Thus, LSI can be used for sensitive and continuous, non-invasive real-time visualization and measurement of relative cortical CBF in excellent spatial-temporal resolution.

Assessment of the influence of navigated transcranial magnetic stimulation on surgical planning for tumors in or near the motor cortex.

BACKGROUND: Brain tumor surgery near the motor cortex requires careful planning to achieve the optimal balance between completeness of tumor resection and preservation of motor function. Navigated transcranial magnetic stimulation (nTMS) can be used to map functionally essential motor areas preoperatively. OBJECTIVE: To evaluate how much influence, benefit, and impact nTMS has on the surgical planning for tumors near the motor cortex. METHODS: This study reviewed the records of 73 patients with brain tumors in or near the motor cortex, mapped preoperatively with nTMS. The surgical team prospectively classified how much influence the nTMS results had on the surgical planning. Stepwise regression analysis was used to explore which factors predict the amount of influence, benefit, and impact nTMS has on the surgical planning. RESULTS: The influence of nTMS on the surgical planning was as follows: it confirmed the expected anatomy in 22% of patients, added knowledge that was not used in 23%, added awareness of high-risk areas in 27%, modified the approach in 16%, changed the planned extent of resection in 8%, and changed the surgical indication in 3%. CONCLUSION: nTMS had an objective benefit on the surgical planning in one fourth of the patients and a subjective benefit in an additional half of the patients. It had an impact on the surgery itself in just more than half of the patients. By mapping the spatial relationship between the tumor and functional motor cortex, nTMS improves surgical planning for tumors in or near the motor cortex.

Watertight dural closure: is it necessary? A prospective randomized trial in patients with supratentorial craniotomies.

OBJECTIVE: The aim of the current study was to prospectively analyze complication rates and costs associated with dural closure in patients undergoing supratentorial craniotomies, randomized for watertight and adaptive dural closures. METHODS: One hundred fifty consecutive patients with supratentorial lesions who were between 18 and 70 years of age were prospectively included. A watertight dural closure was the primary goal (Group A). Whenever this goal could not be achieved, patients were intraoperatively randomized for secondary watertight (Group B) or adaptive dural closure (Group C). Within a follow-up period of 4 weeks, study end points were the occurrence of complications such as subcutaneous fluid collections, impaired wound healing with and without cerebrospinal fluid leakage, and infection. Moreover, we analyzed costs for dural closure for each group separately. RESULTS: Of 150 eligible patients, 13 were excluded according to predefined criteria (Group A, n = 3; Group B, n = 7; Group C, n = 3). From those patients, a primary watertight dural closure could be obtained in 44 (29.4%) patients. A secondary watertight dural closure was performed in 53 (35.3%) patients, and an adaptive dural closure was performed in 53 (35.3%) patients. Complications that were related to dural closure or wound closure were found in 7 patients in Group A, 6 patients in Group B, and 12 patients in Group C (all not significant). The mean total costs, based on time and additional material required in Group A (US $436 +/- 119) or Group B (US $681 +/- 286) were significantly greater compared with adaptive dural closure in Group C (US $213 +/- 142, P < 0.05). CONCLUSION: In supratentorial craniotomies, an adaptive dural closure may represent a safe and cost-effective alternative to watertight dural closure.