High-speed k-linear swept laser using acousto-optic deflectors with Doppler shift compensation for optical coherence tomography.

Swept laser based on the acousto-optic deflector (AOD) is a promising swept source in optical coherence tomography (OCT) applications for its high wavenumber linear sweep without mechanical motion. However, the poor coherence length and the elongated cavity of the laser imposed limitations on the acquisition of high-quality images with adequate imaging depth and high imaging speed. In this Letter, we demonstrate a compact high-speed wavenumber linear swept laser based on AOD using Doppler shift compensation, achieving a high linearity of Pearson's R of 0.999991, a duty cycle of ∼100%, an extended coherence length of 5.7 mm, an output power of 18 mW, and excellent phase stability at a sweep speed of 500 kHz. OCT structural images with a system sensitivity of 103.2 dB and OCT angiography (OCTA) of human palm in vivo have been successfully performed, serving as a compelling demonstration of the excellent performance of this swept laser. We believe that the proposed laser will be of high potential in various clinical and industrial applications in the future.

Multimodal-based machine learning strategy for accurate and non-invasive prediction of intramedullary glioma grade and mutation status of molecular markers: a retrospective study.

BACKGROUND: Determining the grade and molecular marker status of intramedullary gliomas is important for assessing treatment outcomes and prognosis. Invasive biopsy for pathology usually carries a high risk of tissue damage, especially to the spinal cord, and there are currently no non-invasive strategies to identify the pathological type of intramedullary gliomas. Therefore, this study aimed to develop a non-invasive machine learning model to assist doctors in identifying the intramedullary glioma grade and mutation status of molecular markers. METHODS: A total of 461 patients from two institutions were included, and their sagittal (SAG) and transverse (TRA) T2-weighted magnetic resonance imaging scans and clinical data were acquired preoperatively. We employed a transformer-based deep learning model to automatically segment lesions in the SAG and TRA phases and extract their radiomics features. Different feature representations were fed into the proposed neural networks and compared with those of other mainstream models. RESULTS: The dice similarity coefficients of the Swin transformer in the SAG and TRA phases were 0.8697 and 0.8738, respectively. The results demonstrated that the best performance was obtained in our proposed neural networks based on multimodal fusion (SAG-TRA-clinical) features. In the external validation cohort, the areas under the receiver operating characteristic curve for graded (WHO I-II or WHO III-IV), alpha thalassemia/mental retardation syndrome X-linked (ATRX) status, and tumor protein p53 (P53) status prediction tasks were 0.8431, 0.7622, and 0.7954, respectively. CONCLUSIONS: This study reports a novel machine learning strategy that, for the first time, is based on multimodal features to predict the ATRX and P53 mutation status and grades of intramedullary gliomas. The generalized application of these models could non-invasively provide more tumor-specific pathological information for determining the treatment and prognosis of intramedullary gliomas.

Polarization-isolated stretched-pulse mode-locked swept laser for 10.3-MHz A-line rate optical coherence tomography.

Stretched-pulse mode-locked (SPML) lasing based on a chirped fiber Bragg grating (CFBG) has proven to be a powerful method to generate wavelength-swept lasers at speeds of tens of megahertz. However, light transmitted through the CFBG may lead to undesirable laser oscillation that disrupts the mechanism of the laser active mode locking in the theta ring cavity. In this Letter, we demonstrate a simple and low-cost approach to suppress the transmitted light and achieve an effective duty cycle of ∼100% with only one CFBG and no need for intra-cavity semiconductor optical amplifier (SOA) modulation, extra-cavity optical buffering, and post amplification. By utilizing polarization isolation of the bi-directional CFBG, a swept laser centered at 1305 nm, with repetition rate of 10.3 MHz, optical power of 84 mW, and 3 dB bandwidth of 109 nm, is demonstrated. Ultrahigh speed 3D optical coherence tomography (OCT) structural imaging of a human palm in vivo using this swept laser is also demonstrated. We believe that this ultrahigh speed swept laser will greatly promote the OCT technique for industrial and biomedical applications.

A rare case of atypical spinal neurocytoma with EGFR mutation in a 12-year-old boy.

Spinal neurocytoma (SN), although frequently reportedly as tumors of the central nervous system (CNS), are a distinct class of tumors, which can achieve a better prognosis following subtotal or gross total tumor resection. Nonetheless, even with the premise of successful treatment after tumor resection, poor prognosis after treatment due to the SN high proliferation index (typically known as atypical SN) have been reported. Over the past two decades, atypical SN was only reported in four pediatric cases, amidst the lingering controversy surrounding its postoperative adjuvant therapy. Thus, herein, we report a unique case of atypical SN with epidermal growth factor receptor (EGFR) amplification mutation in a 12-year-old boy. We, however, also highlighted the significance of radiotherapy and target therapy for patients with SN.

Flow diverter effect of LVIS stent on cerebral aneurysm hemodynamics: a comparison with Enterprise stents and the Pipeline device.

BACKGROUND: The aim of this study was to quantify the effect of the new Low-profile Visualized Intraluminal Support (LVIS®D) device and the difference of fluid diverting effect compared with the Pipeline device and the Enterprise stent using computational fluid dynamics (CFD). METHODS: In this research, we simulated three aneurysms constructed from 3D digital subtraction angiography (DSA). The Enterprise, LVIS and the Pipeline device were virtually conformed to fit into the vessel lumen and placed across the aneurysm orifice. Computational fluid dynamics analysis was performed to compare the hemodynamic differences such as WSS, Velocity and Pressure among these stents. RESULTS: Control referred to the unstented model, the percentage of hemodynamic changes were all compared to Control. A single LVIS stent caused more wall shear stress reduction than double Enterprise stents (39.96 vs. 30.51 %) and velocity (23.13 vs. 18.64 %). Significant reduction in wall shear stress (63.88 %) and velocity (46.05 %) was observed in the double-LVIS stents. A single Pipeline showed less reduction in WSS (51.08 %) and velocity (37.87 %) compared with double-LVIS stent. The double-Pipeline stents resulted in the most reduction in WSS (72.37 %) and velocity (54.26 %). Moreover, the pressure increased with minuscule extent after stenting, compared with the unstented model. CONCLUSIONS: This is the first study analyzing flow modifications associated with LVIS stents. We found that the LVIS stent has certain hemodynamic effects on cerebral aneurysms: a single LVIS stent caused more flow reductions than the double-Enterprise stent but less than a Pipeline device. Nevertheless, the double-LVIS stent resulted in a better flow diverting effect than a Pipeline device.

Low wall shear stress is associated with the rupture of intracranial aneurysm with known rupture point: case report and literature review.

BACKGROUND: Few previous hemodynamic studies demonstrated the detailed features of rupture point of intracranial aneurysms. The hemodynamic simulation for the case that ruptured during angiography was even rare. In the present study, we studied the hemodynamic characteristics of a posterior communicating artery segment aneurysm that ruptured during angiography and detailed the hemodynamic features at the rupture point. CASE PRESENTATION: One 64-years-patient was 60-69 years old and suffered a subarachnoid hemorrhage within 24 h. Standard digital subtraction angiography and three-dimensional (3D) rotational angiography were performed and an 8 mm left posterior communicating artery segment aneurysm was found. The patient had a seizure immediately following 3D angiography for about 40 s and the immediate follow-up angiography showed contrast extravasation from the tip of identified aneurysms. The consequent vital sign of the patient became unstable. Urgent embolization under general anesthesia was planned, but the relatives refused interventional operation considering the high risk of procedure and poor condition of the patient. The computational fluid dynamic (CFD) method was used to evaluate the hemodynamic characteristics at rupture point, and the results showed that the rupture point was associated with markedly low wall shear stress and high oscillatory shear index without flow impingement. CONCLUSIONS: We present a rare case of which the rupture site was identified during angiography. The hemodynamic simulations revealed that the rupture point was associated with markedly low WSS and high OSI without flow impingement. The result may be unique to this particular aneurysm; however, our findings provide insight into the hemodynamics of rupture point.

Phantom-based experimental validation of fast virtual deployment of self-expandable stents for cerebral aneurysms.

BACKGROUND: Endovascular intervention using a stent is a mainstream treatment for cerebral aneurysms. To assess the effect of intervention strategies on aneurysm hemodynamics, we have developed a fast virtual stenting (FVS) technique to simulate stent deployment in patient-specific aneurysms. However, quantitative validation of the FVS against experimental data has not been fully addressed. In this study, we performed in vitro analysis of a patient-specific model to illustrate the realism and usability of this novel FVS technique. METHODS: We selected a patient-specific aneurysm and reproduced it in a manufactured realistic aneurismal phantom. Three numerical simulation models of the aneurysm with an Enterprise stent were constructed. Three models were constructed to obtain the stented aneurysms: a physical phantom scanned by micro-CT, fast virtual stenting technique and finite element method. The flow in the three models was simulated using a computational fluid dynamics software package, and the hemodynamics parameters for the three models were calculated and analyzed. RESULTS: The computational hemodynamics in the patient-specific aneurysm of the three models resembled the very well. A qualitative comparison revealed high similarity in the wall shear stress, streamline, and velocity plane among the three different methods. Quantitative comparisons revealed that the difference ratios of the hemodynamic parameters were less than 10%, with the difference ratios for area average of wall shear stress in the aneurysm being very low. CONCLUSIONS: In conclusion, the results of the computational hemodynamics indicate that FVS is suitable for evaluation of the hemodynamic factors that affect treatment outcomes.

Hemodynamic alterations after stent implantation in 15 cases of intracranial aneurysm.

BACKGROUND: Stent-assisted coiling technology has been widely used in the treatment of intracranial aneurysms. In the current study, we investigated the intra-aneurysmal hemodynamic alterations after stent implantation and their association with the aneurysm location. METHODS: We first retrospectively studied 15 aneurysm cases [8 internal carotid artery-ophthalmic artery (ICA-OphA) aneurysms and 7 posterior communicating artery (PcoA) aneurysms] treated with Enterprise stents and coils. Then, based on the patient-specific geometries before and after stenting, we built virtual stenting computational fluid dynamics (CFD) simulation models. RESULTS: Before and after the stent deployment, the average wall shear stress (WSS) on the aneurysmal sac at systolic peak changed from 7.04 Pa (4.14 Pa, 15.77 Pa) to 6.04 Pa (3.86 Pa, 11.13 Pa), P = 0.001; the spatially averaged flow velocity in the perpendicular plane of the aneurysm dropped from 0.5 m/s (0.28 m/s, 0.7 m/s) to 0.33 m/s (0.25 m/s, 0.49 m/s), P = 0.001, respectively. Post stent implantation, the WSS in ICA-OphA aneurysms and PcoA aneurysms decreased by 14.4 % (P = 0.012) and 16.6 % (P = 0.018), respectively, and the flow velocity also reduced by 10.3 % (P = 0.029) and 10.5 % (P = 0.013), respectively. Changes in the WSS, flow velocity, and pressure were not significantly different between ICA-OphA and PcoA aneurysms (P > 0.05). Stent implantation did not significantly change the peak systolic pressure in either aneurysm type. CONCLUSION: After the stent implantation, both the intra-aneurysmal flow velocity and WSS decreased independently of aneurysm type (ICA-OphA and PcoA). Little change was observed in peak systolic pressure.

Influence of morphology and hemodynamic factors on rupture of multiple intracranial aneurysms: matched-pairs of ruptured-unruptured aneurysms located unilaterally on the anterior circulation.

BACKGROUND: The authors evaluated the impact of morphological and hemodynamic factors on the rupture of matched-pairs of ruptured-unruptured intracranial aneurysms on one patient's ipsilateral anterior circulation with 3D reconstruction model and computational fluid dynamic method simulation. METHODS: 20 patients with intracranial aneurysms pairs on the same-side of anterior circulation but with different rupture status were retrospectively collected. Each pair was divided into ruptured-unruptured group. Patient-specific models based on their 3D-DSA images were constructed and analyzed. The relative locations, morphologic and hemodynamic factors of these two groups were compared. RESULTS: There was no significant difference in the relative bleeding location. The morphological factors analysis found that the ruptured aneurysms more often had irregular shape and had significantly higher maximum height and aspect ratio. The hemodynamic factors analysis found lower minimum wall shear stress (WSSmin) and more low-wall shear stress-area (LSA) in the ruptured aneurysms than that of the unruptured ones. The ruptured aneurysms more often had WSSmin on the dome. CONCLUSIONS: Intracranial aneurysms pairs with different rupture status on unilateral side of anterior circulation may be a good disease model to investigate possible characteristics linked to rupture independent of patient characteristics. Irregular shape, larger size, higher aspect ratio, lower WSSmin and more LSA may indicate a higher risk for their rupture.

Emotional Problems, Quality of Life and Symptom Burden in Patients with Chordoma.

Chordomas are very rare malignant bone tumors. Following surgery, their effects on neurological, physical, psychological, social, and emotional functioning are substantial and can have a major impact on a patients' quality of life (QOL). In this survey, we aimed to characterize the postoperation health-related QOL and emotional problem in patients with chordoma using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire 30 (EORTC QLQ-C30) and Hamilton Depression Rating Scale (HAMD). The cohort included 100 patients who underwent resection surgery between 2014 and 2020. Being single or divorced, living in a rural area, receiving a diagnosis of sacrococcygeal chordoma, Karnofsky performance status (KPS) ≤ 70, and weight loss were associated with increased likelihood of depression (p < 0.05). Patients who were single or divorced, with KPS ≤ 70, and experiencing weight loss had a higher likelihood of a worse QOL (p < 0.05). The uni- and multivariate logistic regression analyses indicated that the KPS level (p = 0.000) and postoperative radiation therapy (p = 0.009) were related to depression; marital status (p = 0.029), KPS level (p = 0.006), and tumor location (p = 0.033) were related to worse QOL. Certain characteristics placed patients with chordoma at increased risk of emotional problems, which are associated with a lowered QOL and a higher symptom burden. Further knowledge regarding emotional problems is key to improving the QOL for patients with chordoma.

Precise management system for chronic intractable pain patients implanted with spinal cord stimulation based on a remote programming platform: study protocol for a randomized controlled trial (PreMaSy study).

BACKGROUND: Spinal cord stimulation (SCS) is a surgical technique used in patients with chronic intractable pain, and its effectiveness and safety have been validated by multiple studies. However, to maintain an optimal and steady long-term effect is still challenging. Here, we report a new management paradigm integrating smartphone application and remote programming. Chronic pain patients with SCS implants can monitor their pain status on the phone and change stimulation parameters accordingly. The PreMaSy study is a randomized controlled trial to evaluate the clinical effectiveness and safety of this precise management system. METHODS: Patients with chronic intractable pain will be screened for eligibility, and 82 participants are anticipated to be enrolled in this trial. After the electrode implantation, the stimulation effectiveness will be tested. Participants with a reduction of more than 50% in the visual analog scale (VAS) will receive implantation of an implantable pulse generator and randomized (1:1) into the experimental group or control group. All participants will be asked to take online follow-ups and complete assessments using a smartphone application. Daily pain characteristic assessments and monthly quality of life questionnaires are integrated into the App, and participants will be required to complete these assessments. The daily VAS for pain intensity will be monitored and a threshold will be set based on baseline VAS score. The interventional appointment will be scheduled once the threshold is reached. The primary outcome is the health condition and quality of life assessed by the five-level EuroQol five-dimensional questionnaire (EQ-5D-5L). Utility values of EQ-5D-5L will be assessed at baseline and 1, 3, and 6 months post-operative. DISCUSSION: The PreMaSy study aims to evaluate the effectiveness and safety of a novel App-based, patient-centered, self-assessment management system for chronic intractable pain. A randomized controlled trial is designed to test the non-inferiority of this precise management system compared to the monthly online follow-ups. It is also expected to yield valuable experiences regarding precision medicine. TRIAL REGISTRATION: ClinicalTrials.gov NCT05761392. Registered on March 07, 2023.

Improved Ultrafast Power Doppler Imaging by Using Spatiotemporal Non-Local Means Filtering.

The change of microvasculature is associated with the occurrence and development of many diseases. Ultrafast power Doppler imaging (uPDI) is an emerging technology for the visualization of microvessels due to the development of ultrafast plane wave (PW) imaging and advanced clutter filters. However, the low signal-to-noise ratio (SNR) caused by unfocused transmit of PW imaging deteriorates the subsequent imaging of microvasculature. Nonlocal means (NLM) filtering has been demonstrated to be effective in the denoising of both natural and medical images, including ultrasound power Doppler images. However, the feasibility and performance of applying an NLM filter on the ultrasound radio frequency (RF) data have not been investigated so far. In this study, we propose to apply an NLM filter on the spatiotemporal domain of clutter filtered blood flow RF data (St-NLM) to improve the quality of uPDI. Experiments were conducted to compare the proposed method with three different methods (under various similarity window sizes), including conventional uPDI without NLM filtering (Non-NLM), NLM filtering on the obtained power Doppler images (PD-NLM), and NLM filtering on the spatial domain of clutter filtered blood flow RF data (S-NLM). Phantom experiments, in vivo contrast-enhanced human spinal cord tumor experiments, and in vivo contrast-free human liver experiments were performed to demonstrate the superiority of the proposed St-NLM method over the other three methods. Qualitative and quantitative results show that the proposed St-NLM method can effectively suppress the background noise, improve the contrast between vessels and background, and preserve the details of small vessels at the same time. In the human liver study, the proposed St-NLM method achieves 31.05-, 24.49-, and 11.15-dB higher contrast-to-noise ratios (CNRs) and 36.86-, 36.86-, and 15.22-dB lower noise powers than Non-NLM, PD-NLM, and S-NLM, respectively. In the human spinal cord tumor, the full-width at half-maximums (FWHMs) of vessel cross Section are 76, 201, and [Formula: see text] for St-NLM, Non-NLM, and S-NLM, respectively. The proposed St-NLM method can enhance the microvascular visualization in uPDI and has the potential for the diagnosis of many microvessel-change-related diseases.

Clinical Features and Outcomes of Primary Spinal Cord Glioblastoma: A Single-Center Experience and Literature Review.

OBJECTIVE: We aim to elucidate the clinical characteristics of patients with primary spinal cord glioblastoma (PSC GBM) and prognostic factors for their outcomes. METHODS: A cohort of 11 patients with pathologically diagnosed PSC GBM from our center were retrospectively reviewed. The clinical, radiologic, operative, and molecular information were recorded, and univariate analysis was performed to identify prognostic factors. RESULTS: The patient cohort included 5 males (45.5%) and 6 females (54.5%) with a median age of 26 years (range, 9-69 years). The median duration of the preoperative symptoms was 4.0 months (range, 0.5-120 months). Subtotal resection was achieved in 8 patients (72.7%) and partial resection in 3 (27.3%). Two patients (18.2%) underwent postoperative adjuvant chemoradiotherapy, 2 patients underwent (27.3%) chemotherapy only, and 6 patients (54.5%) neither. Two patients underwent additional therapy with bevacizumab. After a mean follow-up of 12.4 months (range, 1-33 months), Kaplan-Meier plot showed that the median progression-free survival and overall survival were 6.0 (range, 0.5-12.0) months and 12.0 (range, 1.0-33.0) months, respectively, and 1-year survival was 31.8%. Age at diagnosis and duration of the preoperative symptoms were confirmed as prognostic factors of progression-free survival and overall survival in univariate analysis (P < 0.05). CONCLUSIONS: Despite aggressive treatment, PSC GBM still has a dismal prognosis and leads to severe neurologic deficit. Age at diagnosis and duration of the preoperative symptoms were confirmed as prognostic factors, yet the role of adjuvant radiochemotherapy and extent of resection are still unclear, necessitating further research.

Fluorescein-guided surgery for spinal gliomas: Analysis of 220 consecutive cases.

OBJECTIVE: Sodium fluorescein (FL) is widely used as a fluorescent tracer for brain tumor resection. However, FL-guided resection of spinal gliomas has been reported only occasionally. To evaluate the safety, characteristics, and usefulness of FL-guided surgery in the resection of spinal glioma. METHODS: Between January 2015 and December 2018, 220 consecutive patients with 227 spinal gliomas underwent FL-guided resection using the Zeiss Pentero 900 surgical microscope with an integrated YELLOW 560 filter. FL evaluation and clinical outcomes were analyzed. RESULTS: No FL-related complications occurred in this series. Entire tumor fluorescence was observed in 161 (70.93%) gliomas, nodular fluorescence in 46 (20.26%) tumors, and no fluorescence in 20 (8.81%) tumors. The intraoperative fluorescence of 217 (95.59%) gliomas was highly correlated with preoperative contrast-enhancing magnetic resonance imaging, except in eight ependymomas, one pilocytic astrocytoma, and one diffuse midline glioma. Gross-total resection was achieved in 78.85% (179/227) of spinal gliomas, including 94.30% (149/158) ependymal tumors and 43.48% (30/69) astrocytic and oligodendroglial tumors. At the final clinical follow-up, the spinal function of 75 (33.04%) patients showed significant improvement, 105 (46.26%) showed stabilization, and 47 (20.70%) showed deterioration. CONCLUSION: FL is a safe and useful real-time tool that could enhance tumor borders or residual tumors and hence increase the gross-total resection rate in cases with contrast-enhanced tumors.

Giant Recurrent Sacral Chordoma.

A 65-year-old man presented with a giant recurrent sacral chordoma after undergoing 7 surgical resections. Neurologic examination revealed urinary incontinence. Magnetic resonance imaging showed a huge mass lesion in the bilateral gluteal regions and multiple metastatic chordomas. Colostomy and wide en bloc excision of the giant recurrent chordoma were performed in April 2017. The tumor weighed 13.15 kg, and histopathologic examination revealed a chordoma. Magnetic resonance imaging performed at the 12-month follow-up showed slight recurrence. In addition, multiple metastatic chordomas localized to the pelvic cavity and the subcutaneous layer of the gluteal region showed significant enlargement. The metastatic chordomas were resected in May 2018. At his last follow-up, the patient presented with an indwelling catheter and a colostomy bag, and the recurrent chordoma showed no visible enlargement.

Accuracy of pedicle screw placement in the thoracic and lumbosacral spines using O-arm-based navigation versus conventional freehand technique.

BACKGROUND: The accuracy and safety of pedicle screw insertion was markedly improved with the introduction of intraoperative three-dimensional navigation system during the last decade. This study aimed to evaluate the accuracy of pedicle screw placement using O-arm-based navigation system versus conventional freehand technique. METHODS: We reviewed the accuracy of 341 thoracic (n = 173) and lumbosacral (n = 168) pedicle screws placed in 60 consecutive patients using either O-arm-based navigation or freehand technique in the Department of Neurosurgery of Beijing Tsinghua Changgung Hospital between January 2015 and June 2018. Patient-specific characteristics, treatment-related characteristics, and screw-specific accuracy were analyzed. The accuracy of pedicle screw placement was measured by Gertzbein-Robbins scale and screw grades A and B were clinically acceptable. RESULTS: One hundred ninety-one screws were inserted in the O-arm-based navigation group and 150 in the freehand group. One hundred eighty-three (95.81%) clinically acceptable screws were placed in the navigation group and 135 (90.00%) in the freehand group (p = 0.034). Twenty-three (6.74%) screw revisions were performed in the two groups (8 screws in the navigation group and 15 screws in the freehand group) and significant difference was observed in thoracic spine (p = 0.018), while no statistical significance was presented in lumbosacral spine (p > 0.05). Twenty-four (12.57%) screws in the navigation group and 24 (16.00%) in the freehand group violated the cortex (p > 0.05). Medial screw deviation was the most common problem in the two groups. CONCLUSION: The O-arm-based navigation exhibits higher accuracy for pedicle screw insertion than the freehand insertion technique.

Intramedullary Spinal Cord Ganglioglioma Presenting as Hyperhidrosis: A Rare Case Report and Literature Review.

BACKGROUND: Hyperhidrosis is caused by sympathetic dysfunction of the central or peripheral nervous system. However, intramedullary spinal cord tumors presenting with hyperhidrosis as an initial symptom have been rarely reported in the literature. CASE DESCRIPTION: This case involves an 18-year-old man who presented with abnormal enhanced sweating and flushing on the bilateral side of his face and neck that had persisted for 6 years. Magnetic resonance (MR) images revealed that at the C7-T2 levels of the spinal cord, a large intramedullary tumor was involved in the cervicothoracic region. The patient underwent gross total resection of the tumor via the fluorescein-guided technique and intraoperative neurophysiologic monitoring. The histopathologic diagnosis revealed ganglioglioma. The symptoms gradually improved after surgery, and the patient presented with virtually complete remission at the end of an 18-month follow-up. CONCLUSIONS: Few cases of intramedullary spinal cord tumors presenting as hyperhidrosis in clinical manifestation have been reported in the literature. Sympathetic irritation by the tumor, particularly in the location around the gray matter of the lateral spinal cord, may account for the hyperhidrosis as the initial symptom in this patient. Therefore, if a patient has autonomic dysfunction, the spine cord should be additionally examined using MR imaging.

Dual-modality optical diagnosis for precise in vivo identification of tumors in neurosurgery.

In neurosurgery, the precise diagnosis and treatment of tumor diseases are challenging to realize. Current clinical diagnoses lack fast and accurate intraoperative information. Therefore, the development of new methods and techniques to assist neurosurgeons intraoperatively is necessary. Optical diagnosis is a promising method to provide accurate information about biological tissues in a short time. Therefore, in this study, we proposed a dual-modality optical diagnostic method through point-to-face registration fusion in the optical system. We incorporated quantitative autofluorescence spectroscopy and optical coherence tomography (OCT) and evaluated our methods in an animal model. Methods: A mouse model consisting of 16 nude mice was built by injecting the mouse brains with human glioma cells. Preoperative bioluminescence imaging was used to evaluate the growth states of tumors and locate the tumor sites. Quantitative autofluorescence spectroscopy, which provided local biochemical information with single-point detection, and OCT, which provided relatively global structural information with en face mapping scanning, were combined using the point-to-face registration fusion method to provide precise diagnostic information for identifying the brain tumors. Postoperative pathology was performed to evaluate the sensitivity and specificity of optical diagnosis. Results: Ex vivo quantitative autofluorescence spectroscopy and OCT imaging were first performed in eight mice to acquire the optimal measuring parameters for tumor staging and identification. We then performed in vivo quantitative autofluorescence spectroscopy and OCT imaging. The results showed that tumor staging could be realized through quantitative autofluorescence spectroscopy, and fusion images could be used to precisely identify tumors. The autofluorescence spectral map, OCT en face map, and fused diagnostic map had average sensitivities of 91.7%, 86.1%, and 95.9% and specificities of 93.2%, 96.0%, and 88.7%, respectively, for tumor identification. Conclusion: The dual-modality optical point-to-face registration fusion method and system we proposed could provide both biochemical information and structural information. The in vivo experimental results validated that the sensitivity (95.9%) of the fused map was higher than that of either single diagnostic modality (86.1% or 91.7%). Tumor staging was realized through quantitative autofluorescence spectroscopy. The proposed method will be applicable to future intelligent theranostic systems and improve many clinical neurosurgeries.

Risk factor analysis of progressive spinal deformity after resection of intramedullary spinal cord tumors in patients who underwent laminoplasty: a report of 105 consecutive cases.

OBJECTIVELaminoplasty has been used in recent years as an alternative approach to laminectomy for preventing spinal deformity after resection of intramedullary spinal cord tumors (IMSCTs). However, controversies exist with regard to its real role in maintaining postoperative spinal alignment. The purpose of this study was to examine the incidence of progressive spinal deformity in patients who underwent laminoplasty for resection of IMSCT and identify risk factors for progressive spinal deformity.METHODSData from IMSCT patients who had undergone laminoplasty at Beijing Tsinghua Changgung Hospital between January 2014 and December 2016 were retrospectively reviewed. Univariate tests and multivariate logistic regression analysis were used to assess the statistical relationship between postoperative spinal deformity and radiographic, clinical, and surgical variables.RESULTSOne hundred five patients (mean age 37.0 ± 14.5 years) met the criteria for inclusion in the study. Gross-total resection (> 95%) was obtained in 79 cases (75.2%). Twenty-seven (25.7%) of the 105 patients were found to have spinal deformity preoperatively, and 10 (9.5%) new cases of postoperative progressive deformity were detected. The mean duration of follow-up was 27.6 months (SD 14.5 months, median 26.3 months, range 6.2-40.7 months). At last follow-up, the median functional scores of the patients who did develop progressive spinal deformity were worse than those of the patients who did not (modified McCormick Scale: 3 vs 2, and p = 0.04). In the univariate analysis, age (p = 0.01), preoperative spinal deformity (p < 0.01), extent of tumor involvement (p < 0.01), extent of abnormal tumor signal (p = 0.02), and extent of laminoplasty (p < 0.01) were identified as factors associated with postoperative progressive spinal deformity. However, in subsequent multivariate logistic regression analysis, only age ≤ 25 years and preoperative spinal deformity emerged as independent risk factors (p < 0.05), increasing the odds of postoperative progressive deformity by 4.1- and 12.4-fold, respectively (p < 0.05).CONCLUSIONSProgressive spinal deformity was identified in 25.7% patients who had undergone laminoplasty for IMSCT resection and was related to decreased functional status. Younger age (≤ 25 years) and preoperative spinal deformity increased the risk of postoperative progressive spinal deformity. The risk of postoperative deformity warrants serious reconsideration of providing concurrent fusion during IMSCT resection or close follow-up after laminoplasty.

Accuracy of Screw Placement and Clinical Outcomes After O-Arm-Navigated Occipitocervical Fusion.

OBJECTIVE: This study aimed to evaluate the accuracy of screw placement and clinical outcomes in patients undergoing occipitocervical fusion. METHODS: Patients who underwent occipitocervical fusion with O-arm-based navigation were retrospectively reviewed between January 2015 and December 2017. The patients' characteristics, clinical and radiographic outcomes, and surgical complications were recorded and analyzed. Cervical screw insertion accuracy was evaluated using the Richter scale. RESULTS: Thirty consecutive patients (11 male and 19 female) with an average treatment age of 40.03 ± 15.19 years were studied. The most common cause was atlantoaxial instability combined with Chiari malformation (63.33%). Weakness (76.67%) and paresthesia (70.00%) were the most common symptoms. Eighty-six occipital and 139 cervical screws were placed using an O-arm-assisted navigation system. In total, 130 (93.53%) cervical screws were graded as group A and 9 (6.47%) as group B. The optimal accuracy rate was 88.41% (61 of 69 screws) in the first 15 patients and 98.57% (69 of 70 screws) in the subsequent 15 patients. The mean follow-up time was 7.50 ± 5.70 months. The mean Japanese Orthopedic Association scores were 13.30 ± 2.41 preoperatively and 15.30 ± 1.60 at final follow-up (P < 0.001), and the mean recovery rate in the Japanese Orthopedic Association score was 53.26 ± 33.82%. Clinical improvement was seen in 25 patients (83.33%), whereas no change was observed in 5 patients (16.67%). The overall complication rate was 6.67% (2/30), with 1 intraoperative vertebral artery injury and 1 postoperative screw loosening. CONCLUSION: Occipitocervical fusion with O-arm-based navigation is effective and safe for treating instability of the craniovertebral junction. Intraoperative navigation can help surgeons insert screws accurately.