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.

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.

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.

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.

Monobloc Frontofacial or Le Fort III Distraction Osteogenesis in Syndromic Craniosynostosis: Three-Dimensional Evaluation of Treatment Outcome and the Need for Central Distraction.

BACKGROUND: The objectives of this study were to investigate the treatment effect, morphology, and volumetric outcomes of monobloc frontofacial or Le Fort III distraction osteogenesis in syndromic craniosynostosis by 3-dimensional evaluation. MATERIALS AND METHODS: Nine consecutive patients underwent monobloc frontofacial or Le Fort III distraction during 2003 to 2012 were included and evaluated. The patient's evaluation is a minimum of a 4-year follow-up. Pretreatment, post-treatment advancement, and relapse were quantified. The changes in intracranial volume, upper airway volume, globe protrusion, advancement at bilateral malar eminence, and central face were calculated from computerized tomography before and after treatment. RESULTS: After distraction, the intracranial volume was increased by 16.4% in average, and the upper airway volume increased by 64.1%. Orbital protrusion improved by 9.9 mm in the left eye and 10.5 mm in the right eye in comparison to the preoperative status. Bilateral malar eminences advancement was greater than the dorsum advancement by 7.1 mm. CONCLUSION: The external distraction osteogenesis device caused significant technical difficulties with advancement of the midface in growing bones. The central midface did not advance as hoped for. This finding may suggest a need for modification in the distraction device in order to improve the central facial distraction vector.

Oligodendrogliomas in Children: Clinical Experiences With 20 Patients.

Oligodendrogliomas occurring rarely in children are incompletely characterized. The purpose of this study was to identify prognostic factors affecting the local control and survival in the management of children with oligodendrogliomas. We retrospectively analyzed clinical data on 20 pediatric patients with oligodendrogliomas treated at Chang Gung Children's Hospital between 1994 and 2014. There were 12 males and 8 females with a median age of 9.2 years at diagnosis (range, 3 mo to 18 y). Eighteen (90%) tumors were located in the cerebral hemispheres, 10 cases were located on the right, 8 on the left. One was located in the third ventricle and 1 in the thoracic spine. Presenting symptoms included seizures (n=7), headache (n=5), visual field defects (n=3), limb weakness (n=2), vomiting (n =1), back pain (n=1), and increased head circumference (n=1). All patients underwent craniotomy: 8 gross total resections, 8 subtotal resections, and 4 biopsies. Nine of the patients had pure oligodendroglioma and 11 had anaplastic oligodendroglioma (WHO grade III or IV). Ten children had adjuvant therapy including radiation (n=7), chemotherapy (n=1) or both (n=2). With the median follow-up of 5.3 years (range, 1.2 to 14.7 y), the 5-year overall survival and disease-free survival rates were 78.9% with 65.0%, respectively. Total tumor resection offers better overall survival regardless of the histologic grading. Our data demonstrate that patients with less than gross total resections are at increased risk for progression and may benefit from more aggressive therapy.

Epstein-Barr Virus-related Posttransplant Lymphoproliferative Disorder in Children: A Single-institution Experience.

We report 4 pediatric cases of biopsy-proven posttransplant lymphoproliferative disorder (PTLD) in the context of allogeneic hematopoietic stem cell transplantation (HSCT). All cases showed diffuse staining with latent membrane protein-1 in immunohistochemistry. The median age at transplant of 4 patients with PTLD was 10.1 years (range, 2.2 to 13.2 y). The median interval between HSCT and the diagnosis of PTLD was 5.5 months (range, 4 to 8 mo). All patients were treated with rituximab at dosage of 375 mg/m at weekly intervals. Reduction of immunosuppression was warranted in all cases. All patients survived with median follow-up duration of 27 months. Although PTLD has been rare following allogeneic HSCT, reduction of immunosuppression combined with rituximab yielded significant response rates in patients with this infrequent but potentially lethal complication. The preliminary finding of this study demonstrated that severe aplastic anemia is closely associated with the development of PTLD in children.

Neurenteric cysts: risk factors and management of recurrence.

BACKGROUND: Neurenteric cysts are rare central nervous system lesions with excellent outcome after total excision. The authors report their experience in the management of these lesions, especially if recurrence occurs. Risk factors of recurrence were analyzed, which have never been reported according to the literature review. METHODS: Twelve patients underwent surgical treatment for neurenteric cysts from April 1998 to July 2015. We retrospectively reviewed the clinical, radiological, operative, and pathological findings for these patients. Correlations between clinical characteristics and recurrence were analyzed. RESULTS: This series included six intracranial and six intraspinal cases. Total resection was achieved in 4 of the 12 cases and partial resection in 8. Six of the patients that underwent partial resection suffered from recurrence, and an additional operation was needed in five. Three of the recurrent intracranial lesions had refractory symptoms and were finally controlled through cyst-peritoneal or ventricle-peritoneal shunts. Risk factors of recurrence were revealed as age ≦30 years old (p = 0.02), subtotal resection in the first operation (p = 0.01), and size of supratentorial NECs >30 ml (p = 0.04). Two-thirds of recurrences occurred in the first 2 years after treatment. CONCLUSIONS: NECs express high recurrence rates when total excision cannot be achieved. The preoperative diagnosis error plays a major role leading to an incorrect surgical strategy and recurrence. MRI with FLAIR and DWI is recommended to improve the preoperative diagnosis. Although timely reoperation is indicated for symptomatic recurrence, adhesion may cause reoperation to become more challenging. C-P or V-P shunts are suggested as the second-line treatment, resulting in excellent prognosis. Patients with mucin-secreting cells noted histologically are susceptible to recurrence.

Successful treatment of early-stage lower extremity lymphedema with side-to-end lymphovenous anastomosis with indocyanine green lymphography assisted.

PURPOSE: This study was to investigate intraoperative assessment of side-to-end lymphovenous anastomosis (LVA) with indocyanine green (ICG) and the correlation between its patency and surgical outcome. METHODS: LVA was applied to five patients with early-stage lower extremity lymphedema. Side-to-end anastomosis and then end-to-end anastomosis were created as a second alternative. Immediately after the anastomosis, ICG was used to confirm its patency. RESULTS: The mean number of anastomoses was 2.0 ± 0.7, and the types of anastomoses were primarily side-to-end and secondarily end-to-end. The mean reduction rate was 63.8 ± 20.2% after LVA at 10 ± 6.4 months of follow-up. In all cases, the affected extremities became soft immediately after surgery, and no cellulitis episodes were observed. CONCLUSION: Side-to-end LVA can be an effective treatment for early-stage lower extremity lymphedema. ICG lymphodynamic assessment is useful not only in the preoperative identification of functional lymphatics but also in the intraoperative visualization of new drainage routes in LVA surgery. © 2015 Wiley Periodicals, Inc. Microsurgery 36:310-315, 2016.

Raised Proinflammatory Cytokine Production Within Cerebrospinal Fluid Precedes Fever Onset in Patients With Neurosurgery-Associated Bacterial Meningitis.

OBJECTIVE: The objective of the present study was to determine whether selective inflammatory cytokine concentrations within cerebrospinal fluid are useful markers for the differential diagnosis of aseptic and bacterial meningitis within neurosurgical patients. DESIGN: Prospective, open-label, observational, cohort study. SETTING: Neurosurgical ICU, Chang Gung Memorial Hospital. PATIENTS: Thirty-two consecutive neurosurgical patients who had postoperative fever following external ventricular drain insertion for the treatment of brain injury underwent serial cerebrospinal fluid cytokine analysis pre and post fever to determine the value of such markers in ascertaining the differential diagnosis of meningitis. INTERVENTION: Cerebrospinal fluid samples were collected on the day of fever onset, as well as on day 2 and 4 pre and post fever development. Tumor necrosis factor-α, interleukin-1ß, interleukin-6, interleukin-8, transforming growth factor-ß, and procalcitonin were subsequently analyzed using enzyme-linked immunosorbent assay analysis techniques. MEASUREMENT AND MAIN RESULTS: Inflammatory marker levels were compared among febrile aseptic, bacterial, and nonmeningitis patients to determine cerebrospinal fluid inflammatory changes over time. Significant increases in cerebrospinal fluid tumor necrosis factor -α, interleukin-1ß, interleukin-6, and interleukin-8 levels were observed within patients with bacterial meningitis at fever onset, which was not evident in aseptic or nonmeningitis patients. Furthermore, significant increases in cerebrospinal fluid tumor necrosis factor-α, interleukin-1ß, interleukin-6, and interleukin-8 levels were detected as early as 4 days prior to fever onset within patients with bacterial meningitis when compared with both aseptic and nonmeningitis groups. Interestingly, procalcitonin was only significantly increased in patients with bacterial meningitis on the fourth day post fever. CONCLUSION: The present study suggests that raised cerebrospinal fluid tumor necrosis factor -α, interleukin-1ß, and interleukin-8 in a temporal manner may indicate early bacterial meningitis development in neurosurgical patients, enabling earlier diagnostic certainty and improved patient outcomes.

Corpus callosum involvement and postoperative outcomes of patients with gliomas.

Corpus callosum involvement is associated with poorer survival in high grade glioma (HGG), but the prognostic value in low grade glioma (LGG) is unclear. To determine the prognostic impact of corpus callosum involvement on progression free survival (PFS) and overall survival (OS) in HGG and LGG, the records of 233 glioma patients treated from 2008 to 2011 were retrospectively reviewed. Preoperative magnetic resonance (MR) images were used to identify corpus callosum involvement. Age, sex, preoperative Karnofsky performance scale, postoperative Eastern Cooperative Oncology Group (ECOG) score and extent of resection (EOR) were evaluated with respect to PFS and OS. The incidence of corpus callosum involvement was similar among HGG (14 %) and LGG (14.5 %). Univariate analysis revealed that PFS and OS were significantly shorter in both WHO grade II and grade IV glioma with corpus callosum involvement (both, p < 0.05). Multivariate analysis showed that grade II glioma with corpus callosum involvement have shorter PFS (p = 0.03), while EOR, instead of corpus callosum involvement (p = 0.16), was an independent factor associated with PFS in grade IV glioma (p < 0.05). Corpus callosum involvement was no longer significantly associated with OS after adjusting age, gender, EOR, preoperative and postoperative performance status (p = 0.16, 0.17 and 0.56 in grade II, III and IV gliomas, respectively). Corpus callosum involvement happened in both LGG and HGG, and is associated with lower EOR and higher postoperative ECOG score both in LGG and HGG. Corpus callosum involvement tends to be an independent prognostic factor for PFS in LGG, but not for OS in LGG or in HGG.

Linear accelerator stereotactic radiosurgery in the management of intracranial arteriovenous malformations: long-term outcome.

BACKGROUND: Arteriovenous malformation (AVM) is one of the cerebrovascular diseases that bear a high risk of hemorrhage. The treatment modalities include microsurgical resection, endovascular embolization, stereotactic radiosurgery, or combinations that vary widely. Several large series have been reported, while data from Asian populations were few. The aim of this study was to examine the efficacy of linear accelerator stereotactic radiosurgery (LINAC SRS) for the treatment of intracranial AVMs, to evaluate the hemorrhage rate and to analyze associated factors. METHODS: One hundred and sixteen patients with AVM were treated with LINAC SRS in a single institute between September 1994 and May 2005 and were retrospectively evaluated. The demographics of patients, clinical characteristics of AVM, the treatment modalities, and the parameters of the LINAC SRS were analyzed. Delayed toxicity and hemorrhage rate after treatment were also evaluated. The AVM obliteration and bleed rates were calculated using the Kaplan-Meier method and Cox regression analyses. RESULTS: The efficacy rate with total obliteration after treatment was 81.9% (95 of 116 patients). The median interval to achieve total obliteration was 49 months. Microsurgical resection combined with SRS for residual AVMs achieved better obliteration rates compared to SRS alone (statistically significant, p = 0.001), while no significant difference was found between the embolization group and the group with no prior treatment (p = 0.895). The Spetzler-Martin grade of AVM is a relative factor of obliteration, higher grades resulting in a worse outcome (p = 0.009). Obliteration was significantly influenced by AVM volume in univariate analysis (p = 0.034), and volume <5 cm(3) contributed to improved obliteration (p = 0.01). There was no statistically significant difference in the hemorrhagic rate and the complication rate between ruptured and unruptured AVMs, while the unruptured group had a higher obliteration rate (p = 0.024). The annual hemorrhage rate after LINAC SRS treatment was 1.9%. The bleeding rate was 3.3% in the first year after radiosurgery, 2.1% in the second year, 1.9% between the second and fifth year, and 1.5% between the fifth and tenth year. Patients with hemorrhagic events before radiosurgery appeared to have a higher rebleeding risk during the latency period. Twenty-three patients (19.8%) had late adverse effects with regard to posttreatment radiological follow-up, but only 1 (0.8%) had newly developed neurological deficits. CONCLUSION: LINAC SRS achieved a high obliteration rate and reduced the risk of hemorrhage effectively in ruptured and unruptured intracranial AVMs. Prior microsurgical resection provided better outcome, while embolization showed no benefit. Adverse effects after treatment are acceptable and require long-term follow-up.

Long-term result of vocal cord paralysis after anterior cervical disectomy.

PURPOSE: Anterior cervical disectomy and fusion (ACDF) is a highly effective and safe method for spinal cord and cervical root decompression. However, vocal cord paralysis (VCP) remains an important cause of postoperative morbidity. The true incidence and recovery course of postoperative VCP is still uncertain. This study is a report on VCP after ACDF to evaluate the incidence, recovery course, and possible risk factors. METHODS: From 2004 to 2008, 1,895 consecutive patients underwent ACDF in our hospital and were followed up for at least 3 years. All surgeons were well trained and used a right-sided exposure. Prolonged VCP, where patients suffered from postoperative VCP lasting more than 3 months, was recorded and analyzed. RESULTS: In this retrospective study, 9 of the 1,895 patients (0.47%) documented prolonged VCP lasting over 3 months. Six of the nine patients had total recovery within 9 months. Only three patients (0.16%) still had symptoms even after 3 years postoperatively. All symptoms of VCP, except hoarseness, could be improved. After matching with 36 non-VCP patients, no differences with regard to longer operative or anesthesia time, shorter neck, obesity, and prevertebral edema. All cases of prolonged course of postoperative VCP occurred in patients who underwent exposure at the C67 level. CONCLUSION: In our study, only 0.47% documented prolonged postoperative VCP, while most patients recovered within 9 months. However, if symptoms last longer, there could be almost permanent VCP (0.16%). In our study, choking and dysphagia subsided mostly within 6 months, but hoarseness remained. The exposure of the C67 level obviously was a risk factor for postoperative VCP.

Creating high-resolution 3D cranial implant geometry using deep learning techniques.

Creating a personalized implant for cranioplasty can be costly and aesthetically challenging, particularly for comminuted fractures that affect a wide area. Despite significant advances in deep learning techniques for 2D image completion, generating a 3D shape inpainting remains challenging due to the higher dimensionality and computational demands for 3D skull models. Here, we present a practical deep-learning approach to generate implant geometry from defective 3D skull models created from CT scans. Our proposed 3D reconstruction system comprises two neural networks that produce high-quality implant models suitable for clinical use while reducing training time. The first network repairs low-resolution defective models, while the second network enhances the volumetric resolution of the repaired model. We have tested our method in simulations and real-life surgical practices, producing implants that fit naturally and precisely match defect boundaries, particularly for skull defects above the Frankfort horizontal plane.

C1-C2 subluxation in enthesitis-related arthritis: two case reports and literature review of ten cases.

BACKGROUND: C1-C2 subluxation is a rare complication of enthesitis-related arthritis (ERA). If left untreated, it may lead to functional impairment or cervical spinal cord compression. This study aims to highlight key points regarding the management of C1-C2 subluxation in ERA. CASE PRESENTATION: We present two cases of C1-C2 subluxation: an 8-year-old boy with ERA and 16-year-old boy with ERA with bilateral sacroiliitis. Ten cases of ERA in the literature were reviewed. The diagnosis of C1-C2 subluxation is mostly based on radiographs and cervical spine computed tomography. All patients were treated with non-steroidal anti-inflammatory drugs. Six ERA patients were treated surgically for cervical fusion. Most ERA patients with sacroiliitis had cervical collar protection. Neurologic abnormalities after treatment were not reported. Despite the use of cervical collar, cervical fusion and persisting ankylosis were found in two ERA patients with sacroiliitis without surgical treatment. CONCLUSIONS: Cervical spine protection and ruling out spinal cord compression should be prioritized, in addition to controlling the underlying inflammation in ERA. Cervical halter traction may be applied after severe cervical inflammation is excluded. To reduce the risk of complications, early recognition and appropriate treatments of C1-C2 subluxation in ERA are essential.

Rescue by hematopoietic progenitor cells derived from engrafted cord blood unit in a child with brain tumor after transplantation for T-cell acute lymphoblastic leukemia.

An 8-year-old boy with T-cell acute lymphoblastic leukemia received unrelated cord blood transplantation in April 2006. His course was uneventful until February 2007, when a hyperintense lesion was noted in the pons. A subsequent bone marrow examination confirmed that he was in remission with full donor chimerism. He was therefore diagnosed with an inoperable brain tumor after cord blood transplantation. Despite radiotherapy for the brain lesion, his neurological status worsened. High-dose chemotherapy with "autologous" progenitor cell rescue was adopted, although the fact that these cells were originally derived from engrafted umbilical cord unit. He was in apparent remission of his brain tumor for 3 years.

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.

Tracheal reconstruction with pedicled tandem grafts engineered by a radial stretch bioreactor.

The engineering of tracheal substitutes is pivotal in improving tracheal reconstruction. In this study, we aimed to investigate the effects of biomechanical stimulation on tissue engineering tracheal cartilage by mimicking the trachea motion through a novel radial stretching bioreactor, which enables to dynamically change the diameter of the hollow cylindrical implants. Applying our bioreactor, we demonstrated that chondrocytes seeded on the surface of Poly (ε-caprolactone) scaffold respond to mechanical stimulation by improvement of infiltration into implants and upregulation of cartilage-specific genes. Further, the mechanical stimulation enhanced the accumulation of cartilage neo-tissues and cartilage-specific extracellular macromolecules in the muscle flap-remodeled implants and reconstructed trachea. Nevertheless, the invasion of fibrous tissues in the reconstructed trachea was suppressed upon mechanical loading.

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.

Predictive Value of Swab Cultures for Cryopreserved Flaps During Delayed Cranioplasties.

OBJECTIVE: To assess the predictive value of swab cultures of cryopreserved skull flaps during cranioplasties for surgical site infections (SSIs). METHODS: A retrospective review was conducted of consecutive patients who underwent delayed cranioplasties with cryopreserved autografts between 2009 and 2017. The results of cultures obtained from swabs and infected surgical sites were assessed. The accuracy, sensitivity, and specificity of swab cultures for SSIs were evaluated. RESULTS: The study included 422 patients categorized into two groups, swab and nonswab, depending on whether swab cultures were implemented during cranioplasties. The overall infection rate was 7.58%. No difference was seen in infection rates between groups. There were 18 false-positive and no true-positive swab culture results. All bacteria between swab cultures and SSI cultures were discordant. Meanwhile, there were 19 false-negative swab cultures. The results showed high specificity but low sensitivity for swab cultures to predict SSI occurrence and the pathogens. CONCLUSIONS: Owing to low accuracy and sensitivity, swab cultures of cryopreserved autografts should not be routinely performed during delayed cranioplasties.