Metastasis of World Health Organization Grade II and Grade III Meningiomas: Long-Term Survival and Associated Factor Analysis.

OBJECTIVE: Metastasis of World Health Organization (WHO) grade II or grade II meningiomas are rare. The aim of this study was to investigate their incidence, associated risk factors, and treatment course. METHODS: Patients with surgically resected WHO grade II or grade III meningiomas were reviewed based on histopathology with the 2016 WHO criteria. Metastasis was diagnosed through whole body image scan followed by surgical resection or biopsy. Clinical factors were analyzed for their association with metastasis. RESULTS: Among the 131 enrolled patients, metastasis was diagnosed after tumor relapse in 7 (incidence rate 3.6%) at a mean 30.9 months after the initial surgery. The metastasis after tumor relapse group had the worst overall survival, followed by tumor relapse without metastasis and nonrelapse groups (P < 0.001). The independent factors associated with metastasis were major vessel compromise by primary tumors (hazard ratio [HR] = 9.9, P = 0.035), tumor relapse time less than 24 months (HR = 7.0, P = 0.036), and subtotal resection without adjuvant radiotherapy to the primary tumor (HR = 3.5, P = 0.047). Neither grading nor histochemical staining was significantly associated with metastasis, whereas higher vascularity seemed to be more common in metastatic lesions than primary tumors. CONCLUSIONS: The presence of metastasis contributed to poor outcomes and was related to earlier tumor relapse and major vessel compromise. Subtotal resection should be followed by adjuvant radiotherapy to reduce the risk of metastasis. Further research is warranted to identify circulating or pathologic biomarkers for the early detection of metastasis.

Pediatric-type diffuse low-grade glioma with T2-FLAIR mismatch sign: a case report and literature review.

INTRODUCTION: Pediatric-type diffuse low-grade gliomas are a new entity that was introduced in the fifth edition of the World Health Organization Classification of Tumors of the Central Nervous System, which was published in 2021. Notably, the information regarding the radiophenotypes of this new entity is limited. OBJECTIVE: T2-FLAIR mismatch sign has been mostly studied in adult-type diffuse gliomas so far. We aimed to present more pediatric cases for future research about T2-FLAIR mismatch signs in pediatric-type diffuse low-grade gliomas. CASE PRESENTATION: The current study presents a case of a 2-year-old boy who has a subcortical tumor at the right precentral frontal region. This tumor exhibited a T2-fluid-attenuated inversion recovery (FLAIR) mismatch sign that was identified as specific for isocitrate dehydrogenase (IDH)-mutant 1p/19q non-co-deleted astrocytomas. The tumor was pathologically identified as pediatric-type diffuse low-grade gliomas, and it tested negative for IDH-1 immunohistochemistry. The whole-exome sequencing of tumor tissue revealed negative results for IDH mutation, 1p/19q co-deletion, MYB rearrangement, and all other potential pathogenic mutations. CONCLUSION: The T2-FLAIR mismatch sign may not be 100% specific for IDH-mutant gliomas, especially in children, and researchers must further investigate the pathophysiology of the T2-FLAIR mismatch sign in brain tumors and the radiophenotypes of entities of pediatric brain tumors.

Robot-Assisted Radiofrequency Ablation Combined with Thermodynamic Simulation for Epilepsy Reoperations.

Repeat craniotomies to treat recurrent seizures may be difficult, and minimally invasive radiofrequency ablation is an alternative therapy. On the basis of this procedure, we aimed to develop a more reliable methodology which is helpful for institutions where real-time image monitoring or electrophysiologic guidance during ablation are not available. We used simulation combined with a robot-assisted radiofrequency ablation (S-RARFA) protocol to plan and execute brain epileptic tissue lesioning. Trajectories of electrodes were planned on the robot system, and time-dependent thermodynamics was simulated with radiofrequency parameters. Thermal gradient and margin were displayed on a computer to calculate ablation volume with a mathematic equation. Actual volume was measured on images after the ablation. This small series included one pediatric and two adult patients. The remnant hippocampus, corpus callosum, and irritative zone around arteriovenous malformation nidus were all treated with S-RARFA. The mean error percentage of the volume ablated between preoperative simulation and postoperative measurement was 2.4 ± 0.7%. No complications or newly developed neurologic deficits presented postoperatively, and the patients had little postoperative pain and short hospital stays. In this pilot study, we preliminarily verified the feasibility and safety of this novel protocol. As an alternative to traditional surgeries or real-time monitoring, S-RARFA served as successful seizure reoperation with high accuracy, minimal collateral damage, and good seizure control.

Three-dimensional deep learning to automatically generate cranial implant geometry.

We present a 3D deep learning framework that can generate a complete cranial model using a defective one. The Boolean subtraction between these two models generates the geometry of the implant required for surgical reconstruction. There is little or no need for post-processing to eliminate noise in the implant model generated by the proposed approach. The framework can be used to meet the repair needs of cranial imperfections caused by trauma, congenital defects, plastic surgery, or tumor resection. Traditional implant design methods for skull reconstruction rely on the mirror operation. However, these approaches have great limitations when the defect crosses the plane of symmetry or the patient's skull is asymmetrical. The proposed deep learning framework is based on an enhanced three-dimensional autoencoder. Each training sample for the framework is a pair consisting of a cranial model converted from CT images and a corresponding model with simulated defects on it. Our approach can learn the spatial distribution of the upper part of normal cranial bones and use flawed cranial data to predict its complete geometry. Empirical research on simulated defects and actual clinical applications shows that our framework can meet most of the requirements of cranioplasty.

Patient-Specific Three-Dimensional Printing Guide for Single-Stage Skull Bone Tumor Surgery: Novel Software Workflow with Manufacturing of Prefabricated Jigs for Bone Resection and Reconstruction.

OBJECTIVE: To describe a novel system workflow to design and manufacture patient-specific three-dimensional (3D) printing jigs for single-stage skull bone tumor excision and reconstruction and to present surgical outcomes of 14 patients. METHODS: A specific computer-aided design/computer-aided manufacturing software and hardware system was set up, including a virtual surgical planning subsystem and a 3D printing-associated manufacturing subsystem. Computed tomography data of the patient's skull were used for 3D rendering of the skull and tumor. The output of patient-specific designing included a 3D printing guide for tumor resection and a 3D printing model of the bone defect after tumor excision. A polymethyl methacrylate implant was fabricated preoperatively and used for repair. RESULTS: The specific 3D printing guide was used to design intraoperative jigs and implants for 14 patients (age range, 1-72 years) with skull bone tumors. In all cases, the cutting jig allowed precise excision of tumor and bone, and implants were exact fits for the defects created. All operative results were successful, without intraoperative or postoperative complications. Postoperative computed tomography scans were obtained for analysis. Postoperative 3D measurement of the skull symmetry index (cranial vault asymmetry index) showed significant improvement of head contour after surgery. CONCLUSIONS: The computer-aided design/computer-aided manufacturing system described allows definitive preoperative planning and fabrication for treatment of skull bone tumors. Apparent benefits of the method include more accurate determination of surgical margins and better oncological outcomes.

Anterior sacral meningocele repair assisted by intraoperative intrathecal fluorescence and 3D printing model: illustrative case.

BACKGROUND: Marfan syndrome is rarely accompanied by anterior sacral meningocele (ASM) resulting from erosion of the sacrum by dural ectasia. ASM may induce symptoms due to severe mass effects. ASM may also mimic ovarian cysts, and the risk of cerebrospinal fluid (CSF) leakage is high if spontaneous rupture of the cyst occurs. In this study, the authors presented a rare case of ASM with iatrogenic CSF leakage in a 34-year-old woman with suspected Marfan syndrome. OBSERVATIONS: The patient initially presented with a giant ASM that was first misdiagnosed as an ovarian cyst. Previously, it had been partially resected, which was followed by iatrogenic CSF leakage. Symptoms of intracranial hypotension, including postural headache and dizziness, developed within 1 month. Brain magnetic resonance imaging (MRI) showed pituitary enlargement, bilateral subdural effusion, and tonsillar herniation. Preoperative computed tomography myelography provided three-dimensional (3D) examination of the deformed sacrum and CSF leakage site. Transabdominal approaches led to primary repair, and repair of the meningocele was achieved by intraoperative fluorescein fluorescence and 3D printed model-guided polymethyl methacrylate bone cement reconstruction. No CSF leakage or recurrent ASM was found at the 1.5-year follow-up visit. LESSONS: Intraoperative intrathecal fluorescence and 3D-printed models are useful for ASM repair. Preoperative MRI is helpful for differentiating ASM from other causes of a huge pelvic mass, including ovarian cyst.

Clinical and endocrinological manifestations of childhood-onset craniopharyngioma before surgical removal: A report from one medical center in Taiwan.

BACKGROUND: Craniopharyngiomas are benign tumors of embryologic origin located in the sellar region. Patients have both neurological and endocrinological symptoms. Symptoms may be subtle in the early clinical course, which leads to delayed diagnosis. This study evaluated the clinical and endocrinological manifestations of childhood-onset craniopharyngioma. METHODS: We retrospectively reviewed medical records of 45 children diagnosed as having craniopharyngioma between 1995 and 2019. We collected data on clinical symptoms and signs, height, weight, biochemical and hormone data, images, operation records, and pathology reports. A three-graded classification system was applied to define the degree of hypothalamic damage (HD). We analyzed clinical and endocrinological manifestations among patients with and without obesity, with short and normal stature, and with differing degrees of HD. RESULTS: Clinical endocrinologic manifestations included adrenocortical insufficiency (42%), central hypothyroidism (37%), short stature (31%), obesity (20%), weight < third percentile (19%), and polyuria or polydipsia (11%). The distribution of height and body mass index (BMI) revealed that a relatively large proportion of patients had short stature and obesity compared to the general population. Patients with grade 2 HD were significantly taller (height median SDS -0.07 vs. -2.05, P = 0.032), and had higher BMI (BMI median standard deviation scores [SDS] 1.14 vs. -0.54, P = 0.039) and shorter time to diagnosis (0.27 vs. 8.29 months, P = 0.007) than were those in the grade 0-1 HD. Delayed diagnosis was associated with short stature (6/7 vs. 4/26, P = 0.001) and no initial neurological symptoms (4/7 vs. 2/28, P = 0.009). CONCLUSION: Growth patterns may change variously depend on the tumor location and the severity of hypothalamic damage. Therefore, monitoring possible neurological symptoms and evaluating the growth patterns of patients during regular outpatient clinical visits are paramount.

Neurological and endocrinological manifestations of 49 children with intracranial pure germinoma at initial diagnosis in Taiwan.

BACKGROUND: Intracranial pure germinoma is a rare extragonadal neoplasm. Affected patients may have motor impairment, visual disturbance, neurological signs, and endocrine disorder, depending on the size and location of the tumor. This study investigated and analyzed patients' demographic data and neuroimaging, clinical, laboratory, and endocrinological findings. METHODS: We performed a retrospective chart review of 49 children diagnosed with pure germinoma in Taiwan from 1990 to 2018. The initial clinical presentation, tumor markers (beta-hCG, alpha fetoprotein, and carcinoembryonic antigen), pituitary function, and brain images were reviewed and analyzed. RESULTS: This study included 49 patients (37 boys and 12 girls). Their ages ranged from 7.5 to 17.9 years, and the mean age at diagnosis was 13.6 years. Initial symptoms included visual disturbance (n = 23, 47.9%), motor impairment (n = 20, 40.8%), polyuria (n = 20, 40.8%), headache (n = 17, 34.7%), dizziness or vertigo (n = 14, 28.6%), nausea/vomiting (n = 13, 26.5%), and short stature (n = 8, 18.2%). Laboratory data indicated growth hormone deficiency or low IGF-1 levels (n = 18, 85.7%), adrenal insufficiency (n = 21, 77.8%), central diabetes insipidus (n = 27, 55.1%), central hypothyroidism (n = 15, 48.4%), and hypogonadotropic hypogonadism (n = 4, 44.4%). CONCLUSION: Intracranial pure germinomas may initially manifest as neurological symptoms or endocrinological findings at diagnosis. As endocrinologic presentation is related to delayed diagnosis, clinicians should be aware of patients with such complaints. Laboratory data should be surveyed carefully, and neuroimaging must be considered if the result is abnormal.

Bicoronal Incision and Frontal-Basal Approach for Removal of Sinonasal Fibrous Dysplasia Complicated by Orbital Subperiosteal Abscess.

BACKGROUND: Fibrous dysplasia (FD) is a benign, slowly progressive disease resulting from the replacement of normal bone by fibro-osseous tissue. The incidence of craniofacial involvement of FD is as high as 23%. Sinonasal involvement of FD may lead to obstruction of the natural sinus ostium, resulting in acute sinusitis. We present a rare case of sinonasal FD complicated by subperiosteal abscess that was removed by bicoronal incision and frontal-basal approach in the second surgery. CASE DESCRIPTION: A 16-year-old male patient presented with painful swelling on his left eye that had persisted for 2 days. Transnasal endoscopic drainage of the left orbital subperiosteal abscess was performed and progressive improvement of the swelling of the left eye was noted. After the acute phase, transcranial removal of the sinonasal bony lesion and mesh reconstruction of the left orbital wall were performed. There has been no progression of FD to date, with 24 months of follow-up. CONCLUSIONS: After the acute phase, radical excision with reconstruction or debulking surgery after skeletal maturation may prevent recurrence. Although malignant transformation is rare, long-term follow-up is necessary for FD.

HoloLens-Based AR System with a Robust Point Set Registration Algorithm.

By the standard of today's image-guided surgery (IGS) technology, in order to check and verify the progress of the surgery, the surgeons still require divert their attention from the patients occasionally to check against the display. In this paper, a mixed-reality system for medical use is proposed that combines an Intel RealSense sensor with Microsoft's Hololens head-mounted display system, for superimposing medical data onto the physical surface of a patient, so the surgeons do not need to divert their attention from their patients. The main idea of our proposed system is to display the 3D medical images of the patients on the actual patients themselves by placing the medical images and the patients in the same coordinate space. However, the virtual medical data may contain noises and outliers, so the transformation mapping function must be able to handle these problems. The transform function in our system is performed by the use of our proposed Denoised-Resampled-Weighted-and-Perturbed-Iterative Closest Points (DRWP-ICP) algorithm, which performs denoising and removal of outliers before aligning the pre-operative medical image data points to the patient's physical surface position before displaying the result using the Microsoft HoloLens display system. The experimental results shows that our proposed mixed-reality system using DRWP-ICP is capable of performing accurate and robust mapping despite the presence of noise and outliers.

Objective and quantifiable measuring mechanism for assessing flap pliability: Our experience with 92 patients.

BACKGROUND: Pliability describes a flaps' ability to bend under spatial limitations, yet a quantifiable measurement for this flexibility does not exist. METHODS: Between January 2015 and January 2017, we applied a novel measuring mechanism to two free flaps for head and neck reconstruction. We allocated a flap pliability score (FPS) to these flaps and observed correlations to common variables. RESULTS: Forty profunda artery perforator (PAP) and 52 anterolateral thigh (ALT) flaps were allotted a score depending on how pliable they performed on our test. Proximal PAP and distal ALT were more pliable than their respective opposite ends. Other interesting conclusions regarding these flaps were also made. CONCLUSIONS: With our technique, pliability of the proximal and distal ends of PAP and ALT flaps was ascertained. Herein, we describe an innovative measuring mechanism via which we can allocate a FPS to any flap and thus obtain information regarding how suitable they are for a given recipient site.

Adjuvant Radiation Therapy Compared with Observation Alone for Postoperative Residual Nonfunctional Pituitary Adenomas.

OBJECTIVE: The management of residual nonfunctional pituitary tumors after surgical resection remains controversial. In this study, we compared the prognosis of postoperative radiation therapy and observation only in patients with residual nonfunctional pituitary adenoma and reviewed the long-term complications after radiation therapy. METHODS: We retrospectively analyzed 90 patients who underwent surgery for nonfunctional pituitary adenomas from January 2008 to April 2012. Residual tumors were classified by size, location, and pathologic staining. Tumor progression was defined as volume progression ≥15% with or without clinical symptoms. Postoperative radiation therapy was performed <1 year after the last surgery. We compared the progression and 3-year and 5-year progression-free survival between the observation group and postoperative radiation therapy group. Postradiation complications including hypopituitarism, diabetes insipidus, deterioration in visual field or acuity, cranial nerve palsy, and hydrocephalus were also analyzed. RESULTS: More of the patients who received postoperative radiation therapy had a tumor progression-free survival of ≥3 years than did those who did not receive postoperative radiation therapy. Postoperative radiation therapy was significantly beneficial for the patients with a tumor size ≥3 cm or with tumors in the cavernous sinus. The most frequent complication after radiation therapy was hypopituitarism and a few cases had third cranial nerve palsy; however, there were no significant relationships with radiation therapy. CONCLUSIONS: In this study, immediate radiation therapy after tumor resection was an effective and relatively safe treatment for residual or progressive nonfunctional pituitary adenomas. Moreover, the long-term complications of radiation therapy were mild.

Postcranioplasty seizures following decompressive craniectomy and seizure prophylaxis: a retrospective analysis at a single institution.

OBJECTIVE: Cranioplasty is a relatively simple and less invasive intervention, but it is associated with a high incidence of postoperative seizures. The incidence of, and the risk factors for, such seizures and the effect of prophylactic antiepileptic drugs (AEDs) have not been well studied. The authors' aim was to evaluate the risk factors that predispose patients to postcranioplasty seizures and to examine the role of seizure prophylaxis in cranioplasty. METHODS: The records of patients who had undergone cranioplasty at the authors' medical center between 2009 and 2014 with at last 2 years of follow-up were retrospectively reviewed. Demographic and clinical characteristics, the occurrence of postoperative seizures, and postoperative complications were analyzed. RESULTS: Among the 583 patients eligible for inclusion in the study, 247 had preexisting seizures or used AEDs before the cranioplasty and 336 had no seizures prior to cranioplasty. Of these 336 patients, 89 (26.5%) had new-onset seizures following cranioplasty. Prophylactic AEDs were administered to 56 patients for 1 week after cranioplasty. No early seizures occurred in these patients, and this finding was statistically significant (p = 0.012). Liver cirrhosis, intraoperative blood loss, and shunt-dependent hydrocephalus were risk factors for postcranioplasty seizures in the multivariable analysis. CONCLUSIONS: Cranioplasty is associated with a high incidence of postoperative seizures. The prophylactic use of AEDs can reduce the occurrence of early seizures.

An Augmented Reality System Using Improved-Iterative Closest Point Algorithm for On-Patient Medical Image Visualization.

In many surgery assistance systems, cumbersome equipment or complicated algorithms are often introduced to build the whole system. To build a system without cumbersome equipment or complicated algorithms, and to provide physicians the ability to observe the location of the lesion in the course of surgery, an augmented reality approach using an improved alignment method to image-guided surgery (IGS) is proposed. The system uses RGB-Depth sensor in conjunction with the Point Cloud Library (PCL) to build and establish the patient's head surface information, and, through the use of the improved alignment algorithm proposed in this study, the preoperative medical imaging information obtained can be placed in the same world-coordinates system as the patient's head surface information. The traditional alignment method, Iterative Closest Point (ICP), has the disadvantage that an ill-chosen starting position will result only in a locally optimal solution. The proposed improved para-alignment algorithm, named improved-ICP (I-ICP), uses a stochastic perturbation technique to escape from locally optimal solutions and reach the globally optimal solution. After the alignment, the results will be merged and displayed using Microsoft's HoloLens Head-Mounted Display (HMD), and allows the surgeon to view the patient's head at the same time as the patient's medical images. In this study, experiments were performed using spatial reference points with known positions. The experimental results show that the proposed improved alignment algorithm has errors bounded within 3 mm, which is highly accurate.

Symptomatic cord compression by paraspinal musculature following cervical laminectomy: rare complication.

PURPOSE: Cervical laminectomy is an effective treatment for multilevel cervical compressive myelopathy. Symptomatic spinal cord compression (SSCC) by paraspinal musculature (PSM) following cervical laminectomy is rarely reported. The aim of this study was to evaluate the frequency and pathogenesis of this complication after cervical laminectomy. METHODS: Between 2007 and 2016, the medical records of 1309 cervical laminectomy patients were reviewed. From these 1309 records, seven patients (five men and two women; average age, 64.12 years; range 48-78 years) with SSCC by PSM following cervical laminectomy were identified. The incidence and possible risk factors of this rare condition were evaluated. RESULTS: The frequency of SSCC by PSM following cervical laminectomy was 0.53%. Presenting symptoms included paralyses and paresthesias, depending on the level and severity of cervical spinal cord compression. The initial onset of neurologic deterioration varied from 12 h to 21 days after operation. Most patients recovered well after surgical management with an average Barthel index of 74.3 at 6 months after surgery. In comparison with 63 controls, this rare complication was associated with preoperative cervical kyphosis, prior antiplatelet therapy, and posterior decompression with prone position. CONCLUSIONS: SSCC by PSM is a rare but devastating complication following cervical laminectomy, especially in those patients with preoperative kyphosis, prior antiplatelet treatment, and decompression with prone position. MRI is an ideal tool to identify this complication. Rapid cervical cord decompression and avoidance of recurrent compressive events can achieve a good clinical outcome. These slides can be retrieved under Electronic Supplementary Material.

Seizures in surgically resected atypical and malignant meningiomas: Long-term outcome analysis.

PURPOSE: Seizures in rare atypical and malignant meningiomas were significantly under-studied. Our aim was to examine the rates, predictors, and seizure control in these meningiomas, and to analyze associations between clinical characteristics and seizure free survival (SFS) following surgical resection in an Asian population. METHODS: We retrospectively analyzed 102 patients with atypical or malignant meningiomas. Seizures occurring before and after the operation were reviewed. We compared demographic data and clinical characteristics including anti-epileptic drug (AED) treatment to extract potential risk factors for seizures. RESULTS: Preoperative and postoperative early seizures occurred in 15 (14.7%) and 13 (12.7%) patients, respectively. All preoperative seizures occurred with tumors located at the convexity or parasagittal area (P = .001) and were influenced by peritumor edema (P = .027). Preoperative seizures were predictive of early seizures occurrence postoperatively (P = .016). Twenty-one patients (20.6%) had late seizures postoperatively. SFS was influenced by preoperative seizures, tumor location, AED use, and tumor relapse (P = .003, .001, .013, and .046, respectively). Among 15 patients with preoperative seizures, malignant meningiomas were associated with shorter SFS than atypical meningiomas (P = .001). Fifty one of 87 patients without preoperative seizures had prophylactic AEDs, and none had early seizures (P = .001). Gross total resection (GTR) of tumors induced more new-onset seizure than subtotal resection (P = .045). CONCLUSION: Convexity and parasagittal area tumors as well as peritumor edema induce seizures. Preoperative seizures and tumor relapse predict seizures postoperatively. AEDs treatment improves SFS, and prophylactic AEDs eliminate early seizures after surgery. GTR has negative impact to seizure control.