Machine Learning-Based Surgical Planning for Neurosurgery: Artificial Intelligent Approaches to the Cranium.

Objectives: Artificial intelligence (AI) applications in neurosurgery have an increasing momentum as well as the growing number of implementations in the medical literature. In recent years, AI research define a link between neuroscience and AI. It is a connection between knowing and understanding the brain and how to simulate the brain. The machine learning algorithms, as a subset of AI, are able to learn with experiences, perform big data analysis, and fulfill human-like tasks. Intracranial surgical approaches that have been defined, disciplined, and developed in the last century have become more effective with technological developments. We aimed to define individual-safe, intracranial approaches by introducing functional anatomical structures and pathological areas to artificial intelligence. Methods: Preoperative MR images of patients with deeply located brain tumors were used for planning. Intracranial arteries, veins, and neural tracts are listed and numbered. Voxel values of these selected regions in cranial MR sequences were extracted and labeled. Tumor tissue was segmented as the target. Q-learning algorithm which is a model-free reinforcement learning algorithm was run on labeled voxel values (on optimal paths extracted from the new heuristic-based path planning algorithm), then the algorithm was assigned to list the cortico-tumoral pathways that aim to remove the maximum tumor tissue and in the meantime that functional anatomical tissues will be least affected. Results: The most suitable cranial entry areas were found with the artificial intelligence algorithm. Cortico-tumoral pathways were revealed using Q-learning from these optimal points. Conclusions: AI will make a significant contribution to the positive outcomes as its use in both preoperative surgical planning and intraoperative technique equipment assisted neurosurgery, its use increased.

Clinical Evaluation of Decompressive Craniectomy in Malignant Middle Cerebral Artery Infarction using 3D Area and Volume Calculations.

OBJECTIVE: We aimed to measure the craniectomy area using three-dimensional (3D) anatomic area and volume calculations to demonstrate that it can be an effective criterion for evaluating survival and functional outcomes of patients with malignant middle cerebral artery (MCA) infarction. MATERIAL AND METHODS: The patients diagnosed with malignant ischemic stroke between 2013 and 2018, for which they underwent surgery due to deterioration in their neurological function, were retrospectively reviewed. Radiological images of all patients were evaluated; total brain tissue volume, ischemic brain tissue volume, total calvarial bone area, and decompression bone area were measured using 3D anatomical area and volume calculations. RESULTS: In total, 45 patients (27 males and 18 females) had been treated with decompressive craniectomy (DC). The removed bone area was found to be significantly related to the outcome in patients with MCA infarction. The average decompression bone area and mean bone removal rate for patients who died after DC were 112 ± 27 cm2 and 20%, whereas these values for surviving patients were 149 ± 29 cm2 and 26% (P = 0.001), respectively. At the 6-month follow-up, the average decompression bone area and mean bone removal rate for patients with severe disability were 126 ± 30 cm2 and 22.2%, whereas these values for patients without severe disability were 159 cm2 ± 26 and 28.4% (P = 0.001), respectively. CONCLUSION: In patients with malignant MCA infarction, the decompression area is associated with favorable functional outcomes, first, survival and second, 6-month modified Rankin scale score distribution after craniectomy.

Relationship Between Degeneration or Sagittal Balance With Modic Changes in the Cervical Spine.

OBJECTIVE: This study evaluates the relationship between degenerative and Modic changes (MCs) in the cervical spine and compares the results with the cervical sagittal balance parameters. METHODS: We retrospectively reviewed 275 patients with neck pain who applied to our outpatient clinic and underwent cervical magnetic resonance imaging (MRI) and cervical anteroposterior (AP)/lateral (Lat) X-ray radiography between January 2016 and January 2018. The clinics, demographic information, and radiological findings of the patients were examined. Modic changes, disc degeneration, and facet degeneration (FD) were examined by cervical MRI, and T1 slope and Cobb angle were measured by cervical AP/Lat X-ray radiography. These results were compared to evaluate their relations with each other. RESULTS: No relationship between the presence or absence of degenerative changes (Modic changes, facet degeneration, and disc degeneration) and sagittal balance parameters (T1 slope and Cobb angle) was found. However, when each cervical segment was examined separately, facet degeneration at the C4-C5 level and Modic changes at the C3-C4, C4-C5, and C6-C7 levels were statistically significant with the Cobb angles, and the Modic changes at the C3-C4 level and disc degeneration at the C2-C3 level were found to be significant with T1 slope values. CONCLUSIONS: Our findings indicate that MCs increased with decreased cervical curvature, increasing disc and facet degeneration, although the causal mechanisms are not clear.

Comparison of Subtracted Computed Tomography from Computed Tomography Perfusion and Digital Subtraction Angiography in Residue Evaluation of Treated Intracranial Aneurysms.

BACKGROUND: Assessing clipped intracranial aneurysms for residues or incomplete occlusions is critical. Digital subtraction angiography (DSA) has been the gold standard for this. Previously, we presented subtracted computed tomography angiography (sub-CTA) from computed tomography perfusion as a more effective noninvasive technique for clipped aneurysms. The aim of this study was to compare effectiveness of sub-CTA with DSA in residue evaluation. METHODS: A retrospective study of 17 patients with aneurysmal subarachnoid hemorrhage operated on at our institution between November 1, 2016, and December 31, 2018, was performed. Residue aneurysms were evaluated with both sub-CTA and DSA. Positive predictive value and negative predictive value were calculated. Correlation between techniques was determined by the McNemar test and κ value. RESULTS: Sensitivity of sub-CTA in residue evaluation was low in aneurysms ≤3 mm (positive predictive value = 60%). DSA detected residue aneurysm in 29% (5/17) of patients, whereas sub-CTA detected residue aneurysm in 11% (2/17). Only 40% of aneurysms (2/5) were demonstrated by sub-CTA, all >3 mm; 60% (3/5) were missed, all ≤3 mm. CONCLUSIONS: This is the first study comparing the effectiveness of sub-CTA from computed tomography perfusion with DSA in residue aneurysm evaluation. Our results were suggestive, but not conclusive. DSA is still the gold standard in residue evaluation. Sub-CTA from computed tomography perfusion can be a reliable method in evaluation of residual aneurysm >3 mm.

Investigation of cytotoxic, genotoxic, and apoptotic effects of curcumin on glioma cells.

Glioblastoma is a malignant tumor of the brain. The treatment of this tumor is still a challenge. Curcumin has been shown to have therapeutic effects when used to treat malignant diseases. However, the molecular mechanisms of its action are not fully elucidated. We hypothesized that reactive oxygen species (ROS) have a key role in curcumin-induced DNA damage, apoptosis, and cell death. To test our hypothesis, cytotoxic, genotoxic, apoptotic, and ROS-generating effects, as well as mitochondrial membrane potentials of curcumin on rat glioma cells (C-6) and normal fibroblastic cells (L-929) were investigated. We examined concentration-dependent cytotoxic, genotoxic, apoptotic, and ROS generating effects of curcumin at C-6 cells and L-929 cells. The cells were incubated with different doses of curcumin (10-100 µM) for 24 hours. Higher doses of curcumin resulted in greater cellular death of cancer than of normal cells at higher concentrations. Curcumin also induced ROS generation in cancer than normal cells in a concentration-dependent manner. Our results showed that curcumin-induced DNA damage in a dose-dependent manner (p < 0.001). At high curcumin concentration such as 80 µM, the proportions of live cells in cancer and normal cell lines were 11.5 and 44.3, respectively. The higher doses of curcumin resulted in greater apoptosis in cancer than normal cells.This in vitro study provided clear evidence that curcumin induced DNA damage and apoptosis. Cytotoxicity may be due to its pro-oxidant activity in a dose-dependent manner in cancer and normal cells. These activities were higher in cancer cells.

Assessment of Auditory Pathways Using Diffusion Tensor Imaging in Patients with Neurofibromatosis Type 1.

AIM: The aim of our study was to determine whether the diffusion properties of the auditory pathways alter between patients with Neurofibromatosis type 1 (NF1) and the healthy subjects. DTI can well demonstrate FA and ADC changes in auditory tracts and it may be a guide to identify the candidates for hearing loss among NF1 children. METHODS: The study population consisted of 43 patients with NF1 and 21 healthy controls. Diffusion tensor imaging (DTI) was used to measure apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values from lemniscus lateralis, colliculus inferior, corpus geniculatum mediale and Heschl's gyrus. The results were compared with those of the control group. RESULTS: The ADC values of lateral lemniscus, colliculus inferior and corpus geniculatum mediale were significantly higher in NF1 compared to those of the control group. On the other hand, decreased FA values were observed in lateral lemniscus and colliculus inferior in patients with NF1. CONCLUSION: The increase in ADC and reduction in FA in the auditory pathways of patients with NF1 may suggest microstructural alterations, such as a decrease in the number of axons, edema or inflammation in the auditory tracts.

Investigation of Brain Impairment Using Diffusion-Weighted and Diffusion Tensor Magnetic Resonance Imaging in Experienced Healthy Divers.

BACKGROUND The aim of this study was to understand the changes of decompression illness in healthy divers by comparing diffusion-weighted (DWI) and diffusion tensor MRI findings among healthy professional divers and healthy non-divers with no history of diving. MATERIAL AND METHODS A total of 26 people were recruited in this prospective study: 11 experienced divers with no history of neurological decompression disease (cohort) and 15 healthy non-divers (control). In all study subjects, we evaluated apparent diffusion coefficient (ADC) and type of diffusion tensor metric fractional anisotropy (FA) values of different brain locations (e.g., frontal and parieto-occipital white matter, hippocampus, globus pallidus, putamen, internal capsule, thalamus, cerebral peduncle, pons, cerebellum, and corpus callosum). RESULTS ADC values of hippocampus were high in divers but low in the control group; FA values of globus pallidus and putamen were lower in divers compared to the control group. DWI depicted possible changes due to hypoxia in different regions of the brain. Statistically significant differences in ADC values were found in hypoxia, particularly in the hippocampus (p=0.0002), while FA values in the globus pallidus and putamen were statistically significant (p=0.015 and p=0.031, respectively). We detected forgetfulness in 6 divers and deterioration in fine-motor skills in 2 divers (p=0.002 and p=0.17, respectively). All of them were examined using neuro-psychometric tests. CONCLUSIONS Repeated hyperbaric exposure increases the risk of white matter damage in experienced healthy divers without neurological decompression illness. The hippocampus, globus pallidus, and putamen are the brain areas responsible for memory, learning, navigation, and fine-motor skills and are sensitive to repeated hyperbaric exposure.

Analysis of genetic polymorphisms associated with intervertebral disc degeneration.

Intervertebral disc degeneration (IVDD) is a common degenerative spinal condition. Recent studies have shown that the incidence of disc herniation and disc degeneration may be explained by genetic factors.  In this study, we investigated the link between various polymorphic variants of the vitamin D receptor (VDR), matrix metalloproteinase 2 (MMP2), and insulin like growth factor 1 receptor (IGF1R) genes and IVDD in patients with IVDD, in Turkey. We examined and genotyped 199 patients with IVDD and 197 healthy individuals. Genomic DNA was isolated from the peripheral blood leukocytes of all participants, and analyzed using real-time PCR. Via melting curve analysis, VDR, MMP2, and IGF1R polymorphism variant distributions were determined. The patients with IVDD showed higher frequencies of the VDR ApaI A allele genotype as compared to the control group; however, there were no significant differences in the frequencies or allelic distributions of the IGF1R and MMP2 genotypes between the IVDD patients and the control group. The incidence of IVDD in these Turkish patients is correlated with the VDR ApaI gene polymorphism, but not with the IGF1R and MMP2 polymorphisms.

The effectiveness of pedicle screw immersion in vancomycin and ceftriaxone solution for the prevention of postoperative spinal infection: A prospective comparative study.

OBJECTIVE: The aim of this study was to evaluate the efficacy of the local application of vancomycin hydrochloride (HCl)-ceftriaxone disodium hemiheptahydrate onto implants before using them to prevent postoperative infection. METHODS: The study included 239 patients (153 women and 86 men; mean age: 48.23 ± 16.77 years) who had thoracolumbar stabilization with transpedicular screws. All surgeries were performed by the same surgeon. Patients were divided into two groups. In the group 1 (n = 104), implants were bathed in a solution of local prophylactic antibiotics for 5 seconds just before implantation. In the group 2 (n = 135), implants were not bathed before implantation. Local antibiotics used in the study was effective against gram positive bacteria (including methicillin resistant Staphylococcus aureus) and gram negative bacteria. The rate of surgical site infection and wound healing time were compared between the groups. RESULTS: A total of 10 patients (4.1%) had deep wound infection and 20 (8.4%) had superficial infection. The most common bacteria was Staphylococcus aureus. One patient died 21 days after the surgery because of sepsis. The wound healed in a mean of 9.66 ± 2.04 days in patients who had no infection and in 32.33 ± 19.64 days in patients with infection (p < 0.001). The patients in group 1 had significantly less deep infection than the patients in group 2 (p < 0.05). However, there was no statistically significant difference between the groups for superficial infection. Patients with vertebral fracture had significantly lower deep infection rate in group 1. The deep infection rate of group 1 patients with diabetes, with bleeding of more than 2000 mL, transfused with blood transfusions above 3 units and with dural injury was significantly lower than those in the group 2. None of the patients had allergic reactions to the drugs used for local prophylaxis. CONCLUSIONS: This study shown that bathing implants in antibiotics solution was an effective local prophylactic method to prevent deep infections in spinal surgeries with instrumentation. LEVEL OF EVIDENCE: Level III, Therapeutic study.

Comparison of the biochemical and radiological criteria for lumbar disc degeneration.

BACKGROUND: The relationship between radiological degeneration criteria on lumbar magnetic resonance imaging (MRI) and both the keratan sulfate (KS) and chondroitin sulfate (ChS) levels was examined in disc material taken from patients undergoing lumbar disc herniation (LDH) surgery. To examine whether the biochemical and radiological degeneration criteria testing the reliability of radiological degeneration findings agreed and to evaluate the contribution of the KS/ChS ratio to disc form (protruding or extruding). METHODS: This was a prospective experimental cohort study. Using enzyme-linked immunosorbent assay, KS and ChS levels were measured in the degenerate nucleus pulposus taken from 71 patients with a diagnosis of LDH who underwent surgery. The degeneration levels and disc form (protruding or extruding) were determined according to the Pfirrmann five-stage grading system on preoperative T2-weighted lumbar MRIs. According to the Pfirrmann system, 28 patients were grade III and 43 were grade IV. The relationship between radiological criteria and the KS/ChS ratio was statistically evaluated. RESULTS: The KS levels (p=0.046) and the KS/ChS ratio (p=0.001) were significantly higher in grade IV patients than in grade III patients. However, there was no difference between the KS and ChS levels and the KS/ChS ratio when patients were classified as protruding or extruding according to their disc structure. Disc structure and biochemical degeneration indicators were not correlated. CONCLUSIONS: The KS level and the KS/ChS ratio were high in patients with marked radiological degeneration on lumbar MRI, demonstrating the sensitivity and reliability of the Pfirrmann five-stage grading system for showing radiological degeneration.

Comparison of TOF MRA, Contrast-Enhanced MRA and Subtracted CTA from CTP in Residue Evaluation of Treated Intracranial Aneurysms.

AIM: To compare effectiveness of contrast-enhanced MRA (CE-MRA), 3D-Time-of-flight MRA (3D-TOF-MRA) and subtracted CTA from CTP (sub-CTA) in residue evaluation of intracranial aneurysms treated either with coiling or clipping. MATERIAL AND METHODS: Sixteen treated aneurysms, which were evaluated with three methods within two weeks after the operation, were enrolled. The success of each imaging techniques in demonstration of residue aneurysm and nearby vessels was compared by Fisher\'s Exact Test. The differences among three was evaluated by Cochran\'s Q test (p ≤ 0.05). RESULTS: Perfusion abnormality was noted in % 81 of clipped and none of coiled patients. Vessel visualization in the vicinity of aneurysm was better in sub-CTA, followed by CE-MRA. In clipped aneurysms, sub-CTA revealed residue aneurysms in % 16,7 of the patients while 3D-TOF-MRA and CE-MRA revealed none. In coiled aneurysms, CE-MRA revealed residue aneurysms in 100 %, and TOF-MRA in 33,3 % while sub-CTA revealed none. Although dramatic differences were noted in the evaluation of residue aneurysm as well as nearby vessel visualization, no statistical significance noted due to very few patients in subcategories Conclusion: This is first study comparing the effectiveness of CE-MRA, 3D-TOF MRA and sub-CTA in residue aneurysms evaluation. Vessel visualization in the vicinity of aneurysm was better in sub-CTA in all regardless of coiling or clipping. Residue aneurysms were more commonly revealed by CE-MRA in coiled patients and more commonly and better shown by sub-CTA in clipped patients in addition of showing perfusion abnormality that's is more common in clipped patients.

Mood and anxiety disorders in patients with chronic low back and neck pain caused by disc herniation.

OBJECTIVE: We investigated the prevalence of mood and anxiety disorders in patients with chronic low back and neck pain caused by disc herniation and the relationships between pain and mood, and anxiety disorders. METHODS: In total, 149 patients with disc herniation and 60 healthy subjects were included. Disc herniation was diagnosed based on a physical examination and magnetic resonance imaging. Mood and anxiety disorders were diagnosed using the Structured Clinical Interview of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition/Clinical Version. RESULTS: The mean age of the study subjects (n = 209) was 45.96 ± 11.45 years. Seventy (46.6%) patients with disc herniation met the criteria for at least one mood or anxiety disorder. The prevalence rates of mood and anxiety disorders were 16.6% and 35.8%, respectively. The most common specific diagnoses were major depression (n = 25, 16.9%) and generalised anxiety disorder (n = 19, 12.8%). CONCLUSIONS: Mood and anxiety disorders were more commonly seen in patients with lumbar or cervical disc herniation than in those without herniation. No relationship was detected between pain severity and mood or anxiety disorders. However, mood and anxiety disorders were associated with neurological deficits.