Does 5-ALA Fluorescence Microscopy Improve Complete Resectability in Cerebral/Cerebellar Metastatic Surgery? A Retrospective Data Analysis from a Cranial Center.

(1) Background: In this study, the intraoperative fluorescence behavior of brain metastases after the administration of 5-aminolevulinic acid (5-ALA) was analyzed. The aim was to investigate whether the resection of brain metastases using 5-ALA fluorescence also leads to a more complete resections and thus to a prolongation of survival; (2) Methods: The following variables have been considered: age, sex, number of metastases, localization, involvement of eloquent area, correlation between fluorescence and primary tumor/subtype, resection, and survival time. The influence on the degree of resection was determined with a control MRI within the first three postoperative days; (3) Results: Brain metastases fluoresced in 57.5% of cases. The highest fluorescence rates of 73.3% were found in breast carcinoma metastases and the histologic subtype adenocarcinoma (68.1%). No correlation between fluorescence behavior and localization, primary tumor, or histological subtype was found. Complete resection was detected in 82.5%, of which 56.1% were fluorescence positive. There was a trend towards improved resectability (increase of 12.1%) and a significantly longer survival time (p = 0.009) in the fluorescence-positive group; (4) Conclusions: 5-ALA-assisted extirpation leads to a more complete resection and longer survival and can therefore represent a low-risk addition to modern surgery for brain metastases.

Retrospective Analysis of Risk Factors for Recurrence of Chronic Subdural Haematoma after Surgery.

(1) Background: In this study, epidemiological, clinical, therapeutical, and haemostaseological variables were investigated regarding their correlation with the recurrence of chronic subdural haematomas to assess the risk of recurrence more reliably in everyday clinical practice. (2) Methods: In our retrospective study, the electronic records of 90 patients who underwent surgery for a chronic subdural haematoma at our institute between 1 January 2017 and 31 May 2021 were analysed regarding previously defined variables. (3) Results: In the patient collective, 33.33% of the 90 patients experienced a recurrence requiring treatment. The occurrence of a recurrence was not statistically significantly related to age, gender, known alcohol abuse, a specific location, extension over one or both hemispheres, the surgical method, or anticoagulant medication. However, the recurrence was statistically significantly related to haematoma width (p = 0.000007), septation (p = 0.005), and the existence of a coagulation disorder not treated with medication (p = 0.04). (4) Conclusions: In our study, the width of the haematoma, septation, and coagulation disorders not treated with medication were documented as risk factors for the occurrence of a chronic subdural haematoma. Identifying of these risk factors could help in adapting individual therapeutic concepts for chronic subdural haematomas.

Patient Satisfaction and Radiologic Assessability After Treatment of Complex Skull Defects With a Custom-Made Cranioplasty From a Thin Titanium Sheet.

OBJECTIVE: The cosmetically good coverage of skull defects is a challenge in neurosurgical clinics. In addition, the skull treated with implants and the underlying structures must remain radiologically assessable. In this examination, the postoperative courses of patients after implantation of CranioTop is described. Digital x-ray, computed tomography, and magnetic resonance images after implantation of CranioTop were evaluated with regard to their assessability. MATERIALS AND METHODS: Between 2018 and 2020, 23 titanium cranioplasties (CranioTop) were implanted to 21 patients. The intraoperative handling, the accuracy of fit, the healing process, the cosmetic result and the physical condition of the patients were examined. In addition, digital x-rays, magnetic resonance imaging, and computed tomography scans of the cranium supplied with CranioTop were examined. RESULTS: The evaluation showed good to very good results regarding patients' satisfaction. There were no severe complications; thirteen patients found the cosmetic result very good; 8 patients assessed the cosmetic result as good. Because of the low thickness and density of the CranioTop plastic there was only low formation of radial stripe artifacts (streaking) and susceptibility artifacts. The assessment of digital x-ray, computed tomography, and magnetic resonance imaging images is possible after implantation of CranioTop. CONCLUSION: The patients treated with CranioTop showed a high level of satisfaction with regard to the cosmetic result and their physical condition. Furthermore, the cranium supplied with CranioTop remains well assessable in radiologic imaging with only slight limitations in magnetic resonance imaging.

Risk factors associated with vasospasm after non-traumatic subarachnoid hemorrhage: a retrospective analysis of 456 patients.

BACKGROUND: The pathophysiology of vasospasm (VS) after non-traumatic subarachnoid hemorrhage is not completely understood. Several risk factors associated with VS were previously reported, partially with conflicting results. The aim of this study was to identify patients at increased risk for VS. METHODS: Retrospective analysis of data from all patients treated in our institutional intensive care unit (ICU) between 2010 and 2016 after non-traumatic subarachnoid hemorrhage. Possible contributing factors for VS studied were: age, sex, aneurysm-localization, treatment option, ICU-stay, ICU mortality, pre-existing condition, medication history, World Federation of Neurosurgical Societies (WFNS) grading system, modified Fisher scale. RESULTS: We obtained data from 456 patients. 184 were male and 272 female patients, respectively. Mean age was 57.7±13.9 and was not different between sexes. In 119 patients, VS was diagnosed after subarachnoid hemorrhage. Incidence of VS was not different between sexes (male: 22.3%, female: 28.7%, P=0.127). Patients with VS were significantly younger (mean age 52.2 vs. 59.7, P<0.001), meanwhile patients aged 36-40 yrs. had the highest incidence of VS. Most VS were found after rupture of middle cerebral artery-aneurysms. Higher incidence of VS was found after aneurysm clipping compared to coiling. VS developed more often in patients with more severe WFNS grade and Fisher scale. In multivariate analysis, age, previous drug abuse and history of anticoagulants were associated with the incidence of VS. CONCLUSIONS: Younger age, middle cerebral artery-aneurysms, aneurysm clipping, previous drug abuse and history of anticoagulants were associated with a higher incidence of VS after non-traumatic subarachnoid hemorrhage. No gender difference was found.

Stereotactic Radiosurgery for Benign Cavernous Sinus Meningiomas: A Multicentre Study and Review of the Literature.

Cavernous sinus meningiomas (CSMs) remain a surgical challenge due to the intimate involvement of their contained nerves and blood vessels. Stereotactic radiosurgery (SRS) is a safe and effective minimally invasive alternative for the treatment of small- to medium-sized CSMs. Objective: To assess the medium- to long-term outcomes of SRS for CSMs with respect to tumour growth, prevention of further neurological deterioration and improvement of existing neurological deficits. This multicentric study included data from 15 European institutions. We performed a retrospective observational analysis of 1222 consecutive patients harbouring 1272 benign CSMs. All were treated with Gamma Knife stereotactic radiosurgery (SRS). Clinical and imaging data were retrieved from each centre and entered into a common database. All tumours with imaging follow-up of less than 24 months were excluded. Detailed results from 945 meningiomas (86%) were then analysed. Clinical neurological outcomes were available for 1042 patients (85%). Median imaging follow-up was 67 months (mean 73.4, range 24-233). Median tumour volume was 6.2 cc (+/-7), and the median marginal dose was 14 Gy (+/-3). The post-treatment tumour volume decreased in 549 (58.1%), remained stable in 336 (35.6%) and increased in only 60 lesions (6.3%), yielding a local tumour control rate of 93.7%. Only 27 (2.8%) of the 60 enlarging tumours required further treatment. Five- and ten-year actuarial progression-free survival (PFS) rates were 96.7% and 90.1%, respectively. Tumour control rates were higher for women than men (p = 0.0031), and also for solitary sporadic meningiomas (p = 0.0201). There was no statistically significant difference in outcome for imaging-defined meningiomas when compared with histologically proven WHO Grade-I meningiomas (p = 0.1212). Median clinical follow up was 61 months (mean 64, range 6-233). Permanent morbidity occurred in 5.9% of cases at last follow-up. Stereotactic radiosurgery is a safe and effective method for treating benign CSM in the medium term to long term.

Multiprofessional Management of Giant Cell Tumors in the Cervical Spine: A Systematic Review.

BACKGROUND: Giant cell tumors of the bone (GCTB) are rare bone tumors, especially in the cervical spine. Generally considered benign, local aggressiveness and metastatic growth have been described. Surgical concepts for GCTB are challenged by complex neurovascular anatomy. Specific clinical management guidelines are nonexistent. This systematic review aims to compile existing evidence on the treatment of GCTB of the cervical spine. METHODS: Four electronic databases were searched: Medline, Embase, Web of Science, and Cochrane Library. All clinical studies reporting the treatment of GCTB in the human cervical spine in English language were found eligible for review. RESULTS: Seven studies were included in the synthesis including a total number of 54 patients. Of those patients, 46 (85%) were treated for naive nonrecurrent GCTB. Only 1 study is considered a cohort study; all other studies were case reports. Generally, intralesional procedures were performed in 13 (24%) cases. Subtotal resections were reported for 11 (20%) patients. Twenty-eight (52%) patients were surgically treated with piecemeal resection, en-bloc resection, or spondylectomy. Thirty-six (67%) patients underwent adjuvant radiotherapy. A combination of radiotherapy and chemotherapy was reported in 2 (4%) cases. Bisphosphonates were prescribed for 9 (17%) patients. Inconsistent reporting of outcome data did not allow for comparative analyses. CONCLUSIONS: Best available evidence suggests that the most aggressive surgical approach should be the main goal of any GCTB surgery. No specific adjuvant or neoadjuvant treatment can be recommended as superior due to a lack of comparative data. Therapeutic approaches need to be planned thoroughly on an individual basis.

Load-Bearing Capacity and Design Advantages of a Custom-Made, Thin Pure-Titanium Cranioplasty (CranioTop).

BACKGROUND: Adequate and stable coverage of cranial contour and continuity defects of any origin is a common challenge in neurosurgical clinics. This study presents the results of investigations concerning the mechanical load-bearing capacity and design advantages of custom-made implants made from a thin, pure-titanium sheet (CranioTop) (CLinstruments, Attendorn, Germany) for covering complex cranial defects. METHODS: In 9 test series, the stability of three differently shaped and sized thin titanium sheet implants was tested using vertical, uniaxial compression with 3 different compression stamps, to investigate the behaviour of these implants in relation to punctiform as well as planar forces. RESULTS: All 9 model implants showed elastic behavior in the synchronously recorded force/displacement diagrams at an impression of up to 2 mm. The forces at 2 mm deformation were between 170.1 and 702.7 Newton. CONCLUSION: Cranioplasty using CranioTop is a stable procedure for covering skull defects, even those of large dimensions. An added advantage is the significant reduction in effort required to prepare the area of the bone margins compared to other current techniques of cranioplasty.

Virtual reality-based evaluation of neurovascular conflict for the surgical planning of microvascular decompression in trigeminal neuralgia patients.

OBJECTIVE: Trigeminal neuralgia (TN) is a lightning bolt of violent, electrifying, and stinging pain, often secondary to the neurovascular conflict (NVC). The vessels involved in NVC are mostly arteries and rarely veins. Evaluation of NVC in the deep infratentorial region is inseparably connected with cranial imaging. We retrospectively analyzed the potential influence of three-dimensional (3D) virtual reality (VR) reconstructions compared to conventional magnetic resonance imaging (MRI) scans on the evaluation of NVC for the surgical planning of microvascular decompression in patients with TN. METHODS: Medical files were retrospectively analyzed regarding patient- and disease-related data. Preoperative MRI scans were retrospectively visualized via VR software to detect the characteristics of NVC. A questionnaire of experienced neurosurgeons evaluated the influence of VR visualization technique on identification of anatomical structures involved in NVC and on surgical strategy. RESULTS: Twenty-four patients were included and 480 answer sheets were evaluated. Compared to conventional MRI, image presentation using 3D-VR modality significantly influenced the identification of the affected trigeminal nerve (p = 0.004), the vascular structure involved in the NVC (p = 0.0002), and the affected side of the trigeminal nerve (p = 0.005). CONCLUSIONS: In patients with TN caused by NVC, the reconstruction of conventional preoperative MRI scans and the spatial and anatomical presentation in 3D-VR models offers the possibility of increased understanding of the anatomy and even more the underlying pathology, and thus influences operation planning and strategy.

Retrospective Comparison of Minimally Invasive and Open Monosegmental Lumbar Fusion, and Impact of Virtual Reality on Surgical Planning and Strategy.

BACKGROUND AND STUDY AIMS: Spinal fusion for symptomatic lumbar spondylolisthesis can be accomplished using an open or minimally invasive surgical (MIS) technique. Evaluation of segmental spondylolisthesis and instabilities and review of their therapies are inseparably connected with lumbar tomographic imaging. We analyzed a cohort of patients who underwent MIS or open monosegmental dorsal fusion and compared surgical outcomes along with complication rates. We furthermore evaluated the influence of virtual reality (VR) visualization on surgical planning in lumbar fusion. MATERIAL AND METHODS: Patient files were retrospectively analyzed regarding patient- and disease-related data, operative performance, surgical outcomes, and perioperative surgical complications. Preoperative computed tomography (CT) and magnetic resonance imaging (MRI) scans were retrospectively visualized via VR software. A questionnaire evaluated the influence of three-dimensional (3D) VR images versus two-dimensional CT and MRI scans on therapy planning, fusion method, and surgical technique and procedure. RESULTS: Overall, 171 patients were included (MIS/open: 90/81). MIS was associated with less blood loss, shorter surgery time and hospital stay, lower complication rates, equivalent long-term patient-reported outcomes, but lower fusion rates and higher late reoperation rates than open surgery. Image presentation using VR significantly influenced the recommended surgical therapies (decompression only/decompression and fusion; p = 0.02), had no significant influence on the recommended fusion method (rigid/dynamic/stand-alone; p = 0.77), and, in cases of rigid fusion, a significant influence on the recommended technique (MIS/open; p = 0.03) and fusion procedure (p = 0.02). CONCLUSION: In patients with monosegmental degenerative or isthmic spondylolisthesis, MIS fusion was advantageous concerning perioperative complication rates and perioperative surgical outcomes, but disadvantageous regarding fusion and reoperation rates compared to open fusion. 3D-VR-based analysis of sectional images significantly influenced the recommended surgical planning.

Impact of Virtual Reality in Arterial Anatomy Detection and Surgical Planning in Patients with Unruptured Anterior Communicating Artery Aneurysms.

Anterior-communicating artery (ACoA) aneurysms have diverse configurations and anatomical variations. The evaluation and operative treatment of these aneurysms necessitates a perfect surgical strategy based on review of three-dimensional (3D) angioarchitecture using several radiologic imaging methods. We analyzed the influence of 3D virtual reality (VR) reconstructions versus conventional computed tomography angiography (CTA) scans on the identification of vascular anatomy and on surgical planning in patients with unruptured ACoA aneurysms. Medical files were retrospectively analyzed regarding patient- and disease-related data. Preoperative CTA scans were retrospectively reconstructed to 3D-VR images and visualized via VR software to detect the characteristics of unruptured ACoA aneurysms. A questionnaire was used to evaluate the influence of VR on the identification of aneurysm morphology and relevant arterial anatomy and on surgical strategy. Twenty-six patients were included and 520 answer sheets were evaluated. The 3D-VR modality significantly influenced detection of the aneurysm-related vascular structure (p = 0.0001), the recommended head positioning (p = 0.005), and the surgical approach (p = 0.001) in the planning of microsurgical clipping. Thus, reconstruction of conventional preoperative CTA scans into 3D images and the spatial presentation in VR models enabled greater understanding of the anatomy and pathology, provided realistic haptic feedback for aneurysm surgery, and influenced operation planning and strategy.

Comparison of stand-alone cage and cage-with-plate for monosegmental cervical fusion and impact of virtual reality in evaluating surgical results.

OBJECTIVES: After ventral decompression of monosegmental cervical spondylotic stenosis, a stand-alone cage (SC) or cage-with-plate (CP) can be inserted for fusion. Postoperative radiological evaluation can be achieved using different imaging modalities. We retrospectively compared complications, as well as clinical and radiological outcomes for both fusion techniques, and analyzed the possible role of virtual reality (VR) in evaluating the postoperative results. PATIENTS AND METHODS: One hundred seventeen patients were included (SC/CP: 54/63). Complications, as well as clinical and radiological outcomes of both fusion techniques were compared. Computed tomography (CT) scans were visualized via VR to measure the smallest cross-sectional area of the intervertebral neuroforamen in the lateral resection region, and to assess the degree of the intersegmental ossification. RESULTS: There were no significant differences between the two fusion techniques regarding perioperative complication rates, fusion rates, or pain parameter (visual analogue scale (VAS) of arm pain, neck disability index). However, advantages regarding subsidence, kyphosis, and VAS of neck pain were found when using the CP versus SC. Using the VR technique, there was no significant difference between the two fusion techniques in the mean size of the cross-sectional area at the end of follow-up. CONCLUSION: Due to the long-term advantages of CP fusion, we prefer a monosegmental cervical spinal fusion using CP. Reconstruction of postsurgical two-dimensional CT images into three-dimensional images, and the spatial and anatomical presentation in VR models, improved the evaluation of these postoperative results.

Brain invasion in meningiomas: does surgical sampling impact specimen characteristics and histology?

Brain invasion (BI) is a new criterion for atypia in meningiomas and therefore potentially impacts adjuvant treatment. However, it remains unclear whether surgical practice and specimen characteristics influence histopathological analyses and the accuracy of detecting BI. Tumor location, specimen characteristics, and rates of BI were compared in meningioma samples obtained from 2938 surgeries in different neurosurgical departments but diagnosed in a single neuropathological institute. Non-skull base tumor location was associated with CNS tissue on the microscopic slides (OR 1.45; p < .001), increasing specimen weight (OR 1.01; p < .001), and remaining tissue not subjected to neuropathological analyses (OR 2.18; p < .001) but not with BI (OR 1.29; p = .199). Specimen weight, rates of residual tissue not subjected to histopathological analyses, of BI and of brain tissue, on the microscopic slides differed among the neurosurgical centers (p < .001, each). Frequency of BI was increased in one department (OR 2.07; p = .002) and tended to be lower in another (OR .61; p = .088). The same centers displayed the highest and lowest rates of brain tissue in the specimen, respectively (p < .001). Moreover, the correlation of BI with the neurosurgical center was not confirmed when only analyzing specimen with evidence of brain tissue in microscopic analyses (p = .223). Detection of BI was not correlated with the intraoperative use of CUSA in subgroup analyses. Rates of brain invasion in neuropathological analyses are not associated with tumor location but differ among some neurosurgical centers. Evidence raises that surgical nuances impact specimen characteristics and therefore the accuracy of the detection of BI.

Early autologous cranioplasty: complications and identification of risk factors using virtual reality visualisation technique.

Background: Cranioplasty (CP) of autologous bone flap after decompressive craniectomy (DC) is known to be associated with a high complication rate, particularly bone flap resorption (BFR). In a retrospective study, we used a novel virtual reality (VR) visualisation technique to identify and evaluate risk factors associated with CP.Method: Twenty-five patients underwent early autologous CP. All complications were recorded. Cranial computed tomography scans were visualised via the VR software to access the fitting accuracy of the bone flap (bone flap size, gap width at trepanation cutting edge, extent of osteoclastic extension).Results: An overall complication rate of 44% was seen, and BFR was the most common (36%). Only 'osteoclastic extension of trepanation' (p = .04) was a significant risk factor for BFR. The factors 'indication for DC' (p = .09) and 'size of bone flap' (p = .09) had a tendency towards influencing the rate of BFR, while 'age' (p = .68), 'time interval between DC and CP' (p = 1.00), and 'gap width' (p = .50) were not considered to influence the BFR rate.Conclusions: DC and subsequent CP is a complication-prone procedure. Therefore, it is relevant to identify and quantify probable risk factors for the most common complications, such as BFR. Here, we found that the extent of osteoclastic extension may impair the patient's healing process. Our investigation was made considerably easier by using the novel VR visualisation technique, which allows parallax free measurements of distances in 3D space.

Virtual Reality-Based Evaluation of Surgical Planning and Outcome of Monosegmental, Unilateral Cervical Foraminal Stenosis.

BACKGROUND: Foraminal cervical nerve root compression can be caused by lateral disk herniation or osteophyte formation of the vertebrae. Improved diagnosis and evaluation can be achieved using different imaging techniques: radiographs, computed tomography (CT), and magnetic resonance imaging. We retrospectively evaluated the potential influence of a virtual reality (VR) visualization technique on surgery planning and evaluation of postoperative results in patients with monosegmental, unilateral osseous cervical neuroforaminal stenosis. METHODS: Seventy-three patients were included. Ventral decompression of the neuroforamen was performed in 41 patients, dorsal decompression in 32 patients. Patients' files were evaluated. CT scans were visualized via VR software to measure the smallest cross-sectional area of the intervertebral neuroforamen in the lateral resection region. A questionnaire evaluated the influence of VR technique on surgical planning and strategy. RESULTS: The VR-technique had a moderate influence on the choice of the approach (ventral or dorsal), a significant influence on the ventral approach strategy, and no influence on the positioning of the patient or the dorsal approach strategy. A significant difference was found in the size of the smallest cross-sectional area of the intervertebral neuroforamen in the lateral resection region between ventral and dorsal approaches, with no correlation to the clinical outcome. CONCLUSIONS: Reconstruction of pre- and postoperative 2D-CT images of the cervical spine into 3D images, and the spatial and anatomical reconstructions in VR models, can be helpful in planning surgical approaches and treatment strategies for patients with cervical foraminal stenoses, and for evaluation of their postoperative results.

Heterotopic Neuroglial Tissue in Sphenoid Ridge.

BACKGROUND: Extracerebral neuroglial heterotopias are rare manifestations of cerebral tissue outside the brain whose most common form is the so-called nasal glioma. In this case report we illustrate the first case of heterotopic neuroglial tissue within the bone of the skull. CASE DESCRIPTION: Our patient underwent surgery for a sphenoid ridge meningioma. Aside from the expected meningioma, histopathologic examination showed a small amount of intraosseous heterotopic neuroglial tissue. CONCLUSIONS: The pathogenesis of cerebral heterotopias is diverse. Most of the midline lesions are probably residuals of former meningoencephaloceles. The pathogenesis of extracranial nonmidline lesions is more questionable. Their cause might be a former trauma, inflammatory disease, or surgery. Another option is that they represent primary neuroglial heterotopias, as it is supposed for manifestations of the lung. The coexistence of a heterotopia and a meningioma in this case is probably a coincidence. It is also debatable whether the broad tumor extension within the bone and/or the heterotopia might go back to alterations of the bone structure.

Fluorescence-Based Measurement of Real-Time Kinetics of Protoporphyrin IX After 5-Aminolevulinic Acid Administration in Human In Situ Malignant Gliomas.

BACKGROUND: Five-aminolevulinic acid (5-ALA) is well established for fluorescence-guided resections of malignant gliomas by eliciting the accumulation of fluorescent protoporphyrin IX (PpIX) in tumors. Because of the assumed time point of peak fluorescence, 5-ALA is recommended to be administered 3 h before surgery. However, the actual time dependency of tumor fluorescence has not yet been evaluated in humans and may have important implications. OBJECTIVE: To investigate the time dependency of PpIX by measuring fluorescence intensities in tumors at various time points during surgery. METHODS: Patients received 5-ALA (20 mg/kg b.w.) 3 to 4 h before surgery. Fluorescence intensities (FI) and estimated tumor PpIX concentrations (CPPIX) were measured in the tumors over time with a hyperspectral camera. CPPIX was assessed using hyperspectral imaging and by evaluating fluorescence phantoms with known CPPIX. RESULTS: A total of 201 samples from 68 patients were included in this study. On average, maximum values of calculated FI and CPPIX were observed between 7 and 8 h after 5-ALA administration. FI and CPPIX both reliably distinguished central strong and marginal weak fluorescence, and grade III compared to grade IV gliomas. Interestingly, marginal (weak) fluorescence was observed to peak later than strong fluorescence (8-9 vs 7-8 h). CONCLUSION: In human in Situ brain tumor tissue, we determined fluorescence after 5-ALA administration to be maximal later than previously thought. In consequence, 5-ALA should be administered 4 to 5 h before surgery, with timing adjusted to internal logistical circumstances and factors related to approaching the tumor.

Dual labeling with 5-aminolevulinic acid and fluorescein in high-grade glioma surgery with a prototype filter system built into a neurosurgical microscope: technical note.

OBJECTIVE: Recent efforts to improve visualization of 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PPIX) fluorescence resulted in a dual-labeling technique, combining it with fluorescein sodium in a prototype setup. Fluorescein identifies regions with blood-brain barrier breakdown in gliomas. However, normally perfused and edematous brain fluoresces unselectively, with strong background enhancement. The aim of this study was to test the feasibility of a novel, integrated filter combination using porphyrins for selective tumor identification and fluorescein for background enhancement. METHODS: A microscope with a novel built-in filter system (YB 475) for visualizing both fluorescein and 5-ALA-induced porphyrins was used. Resection limits were identified with the conventional BLUE 400 filter system. Six patients harboring contrast ring-enhancing lesions were analyzed. RESULTS: The complete surgical field could now be illuminated. Fluorescein was helpful for improving background visualization, and enhancing dura, edematous tissue, and cortex. Overlapping regions with both fluorophores harbored merged orange fluorescence. PPIX fluorescence was better visualized, even in areas beyond a normal working distance of approximately 25 cm, where the BLUE 400 filters recognized no or weak fluorescence. CONCLUSIONS: The novel filter system improved general tissue brightness and background visualization, enhancing fluorescence-guided tumor resection. Furthermore, it appears promising from a scientific perspective, enabling the simultaneous and direct observation of areas with blood-brain barrier breakdown and PPIX fluorescence.

Adverse events in brain tumor surgery: incidence, type, and impact on current quality metrics.

BACKGROUND: The aim of the study was to determine pre-operative factors associated with adverse events occurring within 30 days after neurosurgical tumor treatment in a German center, adjusting for their incidence in order to prospectively compare different centers. METHODS: Adult patients that were hospitalized due to a benign or malignant brain were retrospectively assessed for quality indicators and adverse events. Analyses were performed in order to determine risk factors for adverse events and reasons for readmission and reoperation. RESULTS: A total of 2511 cases were enrolled. The 30 days unplanned readmission rate to the same hospital was 5.7%. The main reason for readmission was tumor progression. Every 10th patient had an unplanned reoperation. The incidence of surgical revisions due to infections was 2.3%. Taking together all monitored adverse events, male patients had a higher risk for any of these complications (OR 1.236, 95%CI 1.025-1.490, p = 0.027). Age, sex, and histological diagnosis were predictors of experiencing any complication. Adjusted by incidence, the increased risk ratios greater than 10.0% were found for male sex, age, metastatic tumor, and hemiplegia for various quality indicators. CONCLUSIONS: We found that most predictors of outcome rates are based on preoperative underlying medical conditions and are not modifiable by the surgeon. Comparing our results to the literature, we conclude that differences in readmission and reoperation rates are strongly influenced by standards in decision making and that comparison of outcome rates between different health-care providers on an international basis is challenging. Each health-care system has to develop own metrics for risk adjustment that require regular reassessment.

Second-look strokectomy of cerebral infarction areas in patients with severe herniation.

OBJECTIVE: Decompressive craniectomies (DCs) are performed on patients suffering large cerebral infarctions. The efficacy of this procedure has been demonstrated in several trials. In some cases, however, this procedure alone is not sufficient and patients still suffer refractory elevations of intracranial pressure (ICP). The goal of this study was to determine whether resection of infarcted tissue, termed strokectomy, performed as a second-look procedure after DC, improves outcome in selected cases. METHODS: The authors retrospectively evaluated data of patients who underwent a DC due to a cerebral infarction at their institution from 2009 to 2016, including patients who underwent a strokectomy procedure after DC. Clinical records, imaging data, outcome scores, and neurological symptoms were analyzed, and clinical outcomes and mortality rates in the strokectomy group were compared to those for similar patients in recently published randomized controlled trials. RESULTS: Of 198 patients who underwent DC due to cerebral infarction, 12 patients underwent strokectomy as a second surgical procedure, with a median National Institutes of Health Stroke Scale (NIHSS) score of 19 for patients with versus 16 for those without secondary strokectomy (p = 0.029). Either refractory increases of ICP > 20 mm Hg or dilated pupils in addition to herniation visible on CT images were triggers for strokectomy surgery. Ten of 12 (83%) patients had infarctions in more than one territory (p < 0.001). After 12 months, 43% of patients had a good outcome according to the modified Rankin Scale (mRS) score (≤ 3). In the subgroup of patients suffering infarctions in more than one vascular territory, functional outcome after 12 months was better (mRS ≤ 3 in 40% of patients in comparison to 9%; p = 0.027). A 1:3 case-control analysis matched to age, side of infarction, sex, and vascular territory confirmed these results (mRS ≤ 3, 42% in comparison to 11%; p = 0.032). Age, NIHSS score on admission, and number of vascular territories involved were identified as risk factors in multivariate analysis (p < 0.05). Patients in the strokectomy group had more infections (p < 0.001). According to these results, the authors developed a scale (Münster Stroke Score, 0-6 points) to predict whether patients might benefit from additional strokectomy. Receiver-operating characteristic (ROC) curve analysis revealed an area under the curve (AUC) of 0.86 (p < 0.001). The authors recommend a Münster Stroke Score of ≥ 3 as a cutoff, with a sensitivity of 92% and specificity of 66%, for predicting benefit from strokectomy. CONCLUSIONS: In this study in comparison to former studies, mortality rates were lower and clinical outcome was comparable to that of previously published trials regarding large cerebral infarctions. Second surgery including strokectomy may help achieve better outcomes, especially in cases of infarction of more than one vascular territory.

Is Visible Aminolevulinic Acid-Induced Fluorescence an Independent Biomarker for Prognosis in Histologically Confirmed (World Health Organization 2016) Low-Grade Gliomas?

BACKGROUND: Approximately 20% of low-grade gliomas (LGG) display visible protoporphyrin fluorescence during surgery after 5-aminolevulinic acid (5-ALA) administration. OBJECTIVE: To determine if fluorescence represents a prognostic marker in LGG. METHODS: Seventy-four consecutive patients with LGG (World Health Organization 2016) were operated on with 5-ALA. Fluorescent tissue was specifically biopsied. Tumor size, age, Karnofsky index, contrast-enhancement, fluorescence, and molecular factors (IDH1/IDH2-mutations, Ki67/MIB1 Index, 1p19q codeletions, ATRX, EGFR, p53 expression, and O6-methylguanine DNA methyltransferase promotor methylation), were related to progression-free survival (PFS), malignant transformation-free survival (MTFS) and overall survival (OS). RESULTS: Sixteen of seventy-four LGGs (21.6%) fluoresced. Fluorescence was partially related to weak enhancement on magnetic resonance imaging and increased (positron emission tomography)PET-FET uptake, but not to Karnofsky Performance Score, tumor size, or age. Regarding molecular markers, only EGFR expression differed marginally (fluorescing vs nonfluorescing: 19% vs 5%; P = .057). Median follow-up was 46.4 mo (95% confidence interval [CI]: 41.8-51.1). PFS, MTFS, and OS were shorter in fluorescing tumors (PFS: median 9.8 mo, 95% CI: 1.00-27.7 vs 45.8, 31.9-59.7, MTFS: 43.0 [27.5-58.5] vs 64.6 [57.7-71.5], median not reached, P = .015; OS: 51.6, [34.8-68.3] vs [68.2, 62.7-73.8], P = .002). IDH mutations significantly predicted PFS, MTFS, and OS. In multivariate analysis IDH status and fluorescence both independently predicted MTFS and OS. PFS was not independently predicted by fluorescence. CONCLUSION: This is the first report investigating the role of ALA-induced fluorescence in histologically confirmed LGG. Fluorescence appeared to be a marker for inherent malignant transformation and OS, independently of known prognostic markers. Fluorescence in LGG might be taken into account when deciding on adjuvant therapies.