Surgical Strategy for Dumbbell-Shaped Cervical Schwannoma at the Vicinity of the Vertebral Artery: The Utilization of Anatomic Layer.

BACKGROUND AND OBJECTIVES: In cases where dumbbell-shaped cervical schwannoma encases the vertebral artery (VA), there is a risk of VA injury during surgery. The objective of this study is to propose a strategy for preserving the VA during the surgical excision of tumors adjacent to the VA through the utilization of anatomic layers. METHODS: A retrospective analysis was conducted on 37 patients who underwent surgery for dumbbell-shaped cervical schwannoma with contacting VA from January 2004 to July 2023. The VA encasement group consisted of 12 patients, and the VA nonencasement group included 25 patients. RESULTS: The perineurium acted as a protective barrier from direct VA exposure or injury during surgery. However, in the VA encasement group, 1 patient was unable to preserve the perineurium while removing a tumor adjacent to the VA, resulting in VA injury. The patient had the intact dominant VA on the opposite side, and there were no new neurological deficits or infarctions after the surgery. Gross total resection was achieved in 25 patients (67.6%), while residual tumor was confirmed in 12 patients (32.4%). Four patients (33.3% of 12 patients) underwent reoperation because of the regrowth of the residual tumor within the neural foramen. In the case of the 8 patients (66.7% of 12 patients) whose residual tumor was located outside the neural foramen, no regrowth was observed, and there was no recurrence of the tumor within the remaining perineurium after total resection. CONCLUSION: In conclusion, when resecting a dumbbell-shaped cervical schwannoma contacting VA, subperineurium dissection prevents VA injury because the perineurium acts as a protective barrier.

Trends in degenerative lumbar spinal surgery during the early COVID-19 pandemic in Republic of Korea: A national study utilizing the national health insurance database.

During the first year of the COVID-19 pandemic, the Republic of Korea (ROK) experienced three epidemic waves in February, August, and November 2020. These waves, combined with the overarching pandemic, significantly influenced trends in spinal surgery. This study aimed to investigate the trends in degenerative lumbar spinal surgery in ROK during the early COVID-19 pandemic, especially in relation to specific epidemic waves. Using the National Health Information Database in ROK, we identified all patients who underwent surgery for degenerative lumbar spinal diseases between January 1, 2019 and December 31, 2020. A joinpoint regression was used to assess temporal trends in spinal surgeries over the first year of the COVID-19 pandemic. The number of surgeries decreased following the first and second epidemic waves (p<0.01 and p = 0.34, respectively), but these were offset by compensatory increases later on (p<0.01 and p = 0.05, respectively). However, the third epidemic wave did not lead to a decrease in surgical volume, and the total number of surgeries remained comparable to the period before the pandemic. When compared to the pre-COVID-19 period, average LOH was reduced by 1 day during the COVID-19 period (p<0.01), while mean hospital costs increased significantly from 3,511 to 4,061 USD (p<0.01). Additionally, the transfer rate and the 30-day readmission rate significantly decreased (both p<0.01), while the reoperation rate remained stable (p = 0.36). Despite the impact of epidemic waves on monthly surgery numbers, a subsequent compensatory increase was observed, indicating that surgical care has adapted to the challenges of the pandemic. This adaptability, along with the stable total number of operations, highlights the potential for healthcare systems to continue elective spine surgery during public health crises with strategic resource allocation and patient triage. Policies should ensure that surgeries for degenerative spinal diseases, particularly those not requiring urgent care but crucial for patient quality of life, are not unnecessarily halted.

Healthcare burden changes by restricted physical activities in lumbar spinal stenosis and spondylolisthesis: a retrospective large cohort study during the COVID-19 pandemic.

BACKGROUND: Lumbar spinal stenosis (LSS) and spondylolisthesis (SPL) are characterized as degenerative spinal pathologies and share considerable similarities. However, opinions vary on whether to recommend exercise or restrict it for these diseases. Few studies have objectively compared the effects of daily physical activity on LSS and SPL because it is impossible to restrict activities ethnically and practically. We investigated the effect of restricting physical activity due to social distancing (SoD) on LSS and SPL, focusing on the aspect of healthcare burden changes during the pandemic period. METHODS: We included first-visit patients diagnosed exclusively with LSS and SPL in 2017 and followed them up for two years before and after the implementation of the SoD policy. As controls, patients who first visited in 2015 and were followed for four years without SoD were analyzed. The common data model was employed to analyze each patient's diagnostic codes and treatments. Hospital visits and medical costs were analyzed by regression discontinuity in time to control for temporal effects on dependent variables. RESULTS: Among 33,484 patients, 2,615 with LSS and 446 with SPL were included. A significant decrease in hospital visits was observed in the LSS (difference, -3.94 times/month·100 patients; p = 0.023) and SPL (difference, -3.44 times/month·100 patients; p = 0.026) groups after SoD. This decrease was not observed in the data from the control group. Concerning medical costs, the LSS group showed a statistically significant reduction in median copayment (difference, -$45/month·patient; p < 0.001) after SoD, whereas a significant change was not observed in the SPL group (difference, -$19/month·patient; p = 0.160). CONCLUSION: Restricted physical activity during the SoD period decreased the healthcare burden for patients with LSS or, conversely, it did not significantly affect patients with SPL. Under circumstances of physical inactivity, patients with LSS may underrate their symptoms, while maintaining an appropriate activity level may be beneficial for patients with SPL.

Screening patients requiring secondary lumbar surgery for degenerative lumbar spine diseases: a nationwide sample cohort study.

This study aims to identify healthcare costs indicators predicting secondary surgery for degenerative lumbar spine disease (DLSD), which significantly impacts healthcare budgets. Analyzing data from the National Health Insurance Service-National Sample Cohort (NHIS-NSC) database of Republic of Korea (ROK), the study included 3881 patients who had surgery for lumbar disc herniation (LDH), lumbar spinal stenosis without spondylolisthesis (LSS without SPL), lumbar spinal stenosis with spondylolisthesis (LSS with SPL), and spondylolysis (SP) from 2006 to 2008. Patients were categorized into two groups: those undergoing secondary surgery (S-group) and those not (NS-group). Surgical and interim costs were compared, with S-group having higher secondary surgery costs ($1829.59 vs $1618.40 in NS-group, P = 0.002) and higher interim costs ($30.03; 1.86% of initial surgery costs vs $16.09; 0.99% of initial surgery costs in NS-group, P < 0.0001). The same trend was observed in LDH, LSS without SPL, and LSS with SPL (P < 0.0001). Monitoring interim costs trends post-initial surgery can effectively identify patients requiring secondary surgery.

Multi-pose-based convolutional neural network model for diagnosis of patients with central lumbar spinal stenosis.

Although the role of plain radiographs in diagnosing lumbar spinal stenosis (LSS) has declined in importance since the advent of magnetic resonance imaging (MRI), diagnostic ability of plain radiographs has improved dramatically when combined with deep learning. Previously, we developed a convolutional neural network (CNN) model using a radiograph for diagnosing LSS. In this study, we aimed to improve and generalize the performance of CNN models and overcome the limitation of the single-pose-based CNN (SP-CNN) model using multi-pose radiographs. Individuals with severe or no LSS, confirmed using MRI, were enrolled. Lateral radiographs of patients in three postures were collected. We developed a multi-pose-based CNN (MP-CNN) model using the encoders of the three SP-CNN model (extension, flexion, and neutral postures). We compared the validation results of the MP-CNN model using four algorithms pretrained with ImageNet. The MP-CNN model underwent additional internal and external validations to measure generalization performance. The ResNet50-based MP-CNN model achieved the largest area under the receiver operating characteristic curve (AUROC) of 91.4% (95% confidence interval [CI] 90.9-91.8%) for internal validation. The AUROC of the MP-CNN model were 91.3% (95% CI 90.7-91.9%) and 79.5% (95% CI 78.2-80.8%) for the extra-internal and external validation, respectively. The MP-CNN based heatmap offered a logical decision-making direction through optimized visualization. This model holds potential as a screening tool for LSS diagnosis, offering an explainable rationale for its prediction.

The iterative implementation of a comprehensive enhanced recovery after surgery protocol in all spinal surgery in Korea: a comparative analysis of clinical outcomes and medical costs between primary spinal tumors and degenerative spinal diseases.

OBJECTIVE: Most studies on the enhanced recovery after surgery (ERAS) protocol in spine surgery have focused on patients with degenerative spinal diseases (DSDs), resulting in a lack of evidence for a comprehensive ERAS protocol applicable to patients with primary spine tumors (PSTs) and other spinal diseases. The authors had developed and gradually adopted components of the comprehensive ERAS protocol for all spine surgical procedures from 2003 to 2011, and then the current ERAS protocol was fully implemented in 2012. This study aimed to evaluate the impact and the applicability of the comprehensive ERAS protocol across all spine surgical procedures and to compare outcomes between the PST and DSD groups. METHODS: Adult spine surgical procedures were conducted from 2003 to 2021 at the Seoul National University Hospital Spine Center and data were retrospectively reviewed. The author divided the study periods into the developing ERAS (2003-2011) and post-current ERAS (2012-2021) periods, and outcomes were compared between the two periods. Surgical procedures for metastatic cancer, infection, and trauma were excluded. Interrupted time series analysis (ITSA) was used to assess the impact of the ERAS protocol on medical costs and clinical outcomes, including length of stay (LOS) and rates of 30-day readmission, reoperation, and surgical site infection (SSI). Subgroup analyses were conducted on the PST and DSD groups in terms of LOS and medical costs. RESULTS: The study included 7143 surgical procedures, comprising 1494 for PSTs, 5340 for DSDs, and 309 for other spinal diseases. After ERAS protocol implementation, spine surgical procedures showed significant reductions in LOS and medical costs by 22% (p = 0.008) and 22% (p < 0.001), respectively. The DSD group demonstrated a 16% (p < 0.001) reduction in LOS, whereas the PST group achieved a 28% (p < 0.001) reduction, noting a more pronounced LOS reduction in PST surgical procedures (p = 0.003). Medical costs decreased by 23% (p < 0.001) in the DSD group and 12% (p = 0.054) in the PST group, with a larger cost reduction for DSD surgical procedures (p = 0.021). No statistically significant differences were found in the rates of 30-day readmission, reoperation, and SSI between the developing and post-current ERAS implementation periods (p = 0.65, p = 0.59, and p = 0.52, respectively). CONCLUSIONS: Comprehensive ERAS protocol implementation significantly reduced LOS and medical costs in all spine surgical procedures, while maintaining comparable 30-day readmission, reoperation, and SSI rates. These findings suggest that the ERAS protocol is equally applicable to all spine surgical procedures, with a more pronounced effect on reducing LOS in the PST group and on reducing medical costs in the DSD group.

The precise midline myelotomy through anatomical posterior median septum by dissecting dorsal column in microsurgical resection of ependymoma (2-dimensional operative video).

Although resection is the gold standard treatment for spinal ependymoma, permanent neurological deterioration has been reported postoperatively in 20%-27% of patients. Despite thorough dissection of the tumor from its surroundings, conventional longitudinally directed midline myelotomy can lead to injury to the dorsal column, possibly due to deformation of the posterior median septum as the tumor grows. To address this issue, the authors have been performing precise midline myelotomy through the anatomical posterior median septum by directly dissecting the dorsal column. This video presents the principles and application of this technique.

Surgical treatment of spondylolisthesis by oblique lumbar interbody fusion and transpedicular screw fixation: Comparison between conventional double position versus navigation-assisted single lateral position.

BACKGROUND AND OBJECTIVES: Oblique lumbar interbody fusion (OLIF) procedures involve anterior insertion of interbody cage in lateral position. Following OLIF, insertion of pedicle screws and rod system is performed in a prone position (OLIF-con). The location of the cage is important for restoration of lumbar lordosis and indirect decompression. However, inserting the cage at the desired location is difficult without reduction of spondylolisthesis, and reduction after insertion of interbody cage may limit the amount of reduction. Recent introduction of spinal navigation enabled both surgical procedures in one lateral position (OLIF-one). Therefore, reduction of spondylolisthesis can be performed prior to insertion of interbody cage. The objective of this study was to compare the reduction of spondylolisthesis and the placement of cage between OLIF-one and OLIF-con. METHODS: We retrospectively reviewed 72 consecutive patients with spondylolisthesis for this study; 30 patients underwent OLIF-one and 42 underwent OLIF-con. Spinal navigation system was used for OLIF-one. In OLIF-one, the interbody cage was inserted after reducing spondylolisthesis, whereas in OLIF-con, the cage was inserted before reduction. The following parameters were measured on X-rays: pre- and postoperative spondylolisthesis slippage, reduction degree, and the location of the cage in the disc space. RESULTS: Both groups showed significant improvement in back and leg pains (p < .05). Transient motor or sensory changes occurred in three patients after OLIF-con and in two patients after OLIF-one. Pre- and postoperative slips were 26.3±7.7% and 6.6±6.2% in OLIF-one, and 23.1±7.0% and 7.4±5.8% in OLIF-con. The reduction of slippage was 74.4±6.3% after OLIF-one and 65.4±5.7% after OLIF-con, with a significant difference between the two groups (p = .04). The cage was located at 34.2±8.9% after OLIF-one and at 42.8±10.3% after OLIF-con, with a significant difference between the two groups (p = .004). CONCLUSION: Switching the sequence of surgical procedures with OLIF-one facilitated both the reduction of spondylolisthesis and the placement of the cage at the desired location.

Impact of C3 laminectomy on cervical sagittal alignment in cervical laminoplasty: a prospective, randomized controlled trial comparing clinical and radiological outcomes between C3 laminectomy with C4-C6 laminoplasty and C3-C6 laminoplasty.

BACKGROUND CONTEXT: C3 laminectomy in cervical laminoplasty is a modified laminoplasty technique that can preserve the semispinalis cervicis muscle attached to the C2 spinous process. Several previous studies have shown that this technique can lead to better outcomes of postoperative axial neck pain and C2-C3 range of motion (ROM) than conventional cervical laminoplasty. However, there is still a lack of understanding of total and proportional postoperative cervical sagittal alignment outcomes. PURPOSE: To assess the effects of C3 laminectomy in cervical laminoplasty on postoperative cervical alignment and clinical outcomes. DESIGN: A single-center, patient-blinded, randomized controlled trial. PATIENT SAMPLE: We included consecutive 126 patients diagnosed with cervical spondylotic myelopathy (CSM) or ossification of posterior longitudinal ligament (OPLL) who were scheduled for cervical laminoplasty from March 2017 to January 2020. OUTCOME MEASURES: The primary outcome measures were C2-C7 Cobb angle (CA) and neck disability index (NDI). Secondary outcomes measures included other clinical outcomes and radiographic parameters including segmental Cobb angle and presence of C2-C3 interlaminar fusion. METHODS: Patients were randomly allocated to either the C3 laminectomy with C4-C6 laminoplasty group (LN group) or the C3-C6 laminoplasty group (LP group) at a 1:1 ratio. Laminoplasty was performed using a unilateral open-door technique and stabilized with titanium mini plates. A linear mixed model analysis was employed to examine the longitudinal data from postoperative 1-year through 3-year. Additional analysis between three types of cervical sagittal alignment morphology was done. RESULTS: Among 122 patients who were randomly allocated to one of two groups (LN group, n=61; LP group, n=61), modified intent-to-treat analysis was done for 109 patients (LN group, n=51, LP group, n=58) who had available at least a year of postoperative data. Postoperative C2-C7 CA was not significantly different between the two groups. However, NDI was significantly different between the two groups (12.8±1.0 in the LN group vs 8.6±1.0 in LP group, p=.005), which exceeded the minimum clinically important difference (MCID). The postoperative C2-C3 CA was significantly greater in the LN group (7.1±0.5° in LN group vs 3.2±0.5° in LP group, p<.001) while C4-C7 CA was significantly smaller in the LN group (3.9±0.8° in LN group vs 7.7±0.7° in LP group, p<.001) with greater cSVA in the LN group (31.6±1.4 mm in LN group vs 25.5±1.3 mm in LP group at postoperative 3-year, p=.002). Postoperative Euro-Quality of Life-5 Dimension (EQ-5D), numerical rating scores for neck pain (NRS-N) were significantly better in the LP group than in the LN group (all p<.05) and only EQ-5D surpassed the MCID. The C2-C3 fusion rate was significantly different between the LN group (9.8%) and the LP group (44.8%) (p<.001). The LN group showed a higher prevalence of a specific cervical alignment morphology characterized by a sigmoid shape with proximal lordosis and distal kyphosis (S curve). This S curve demonstrated significantly unfavorable outcomes across multiple outcome variables. CONCLUSION: The impact of C3 laminectomy in cervical laminoplasty on postoperative kyphosis among patients with CSM or OPLL did not significantly differ from that of C3-C6 laminoplasty. However, C3 laminectomy in cervical laminoplasty might result in an unfavorable clinical outcome with an unbalanced cervical sagittal alignment characterized by a sigmoid shape with proximal lordosis and distal kyphosis.

Is laminectomy necessary for C1-C2 epidural schwannomas?

PURPOSE: Spinal schwannomas often require laminectomy for gross total resection. However, laminectomy may not be necessary due to the unique anatomy of epidural schwannomas at the C1-2 level, even with the intradural part. This study aimed to determine the need for laminectomy by comparing factors between patients who underwent laminectomy and those who did not and to identify the benefits of not performing laminectomy. METHODS: Fifty patients with spinal epidural schwannoma confined to C1-C2 level were retrospectively collected and divided into groups based on whether laminectomy was intended and performed. In all cases where laminectomy was conducted, patients underwent laminoplasty using microplate-and-screws, which deviates from the conventional laminectomy approach. Tumor characteristics were compared, and a cut-off value for laminectomy was determined. Outcomes were compared between groups, and factors influencing laminectomy were identified. Postoperative changes in cervical curves were measured. RESULTS: The diameter of the intradural part of the tumor was significantly longer in the laminectomy performed group, with a 14.86 mm cut-off diameter requiring laminectomy. Recurrence rates did not differ significantly between groups. Surgery time was substantially longer for the laminectomy performed group. No significant changes were observed in Cobb's angles of Oc-C2, C1-C2, and Oc-C1 before and after surgery. CONCLUSION: The study showed that the diameter of the intradural part of the tumor influenced the decision to perform laminectomy for removing epidural schwannomas at C1-C2. The cut-off value of the diameter of the intradural part of the tumor for the laminectomy was 14.86 mm. Not performing laminectomy can be a viable option with no significant differences in removal and complication rates.

Nationwide sample data analysis of additional surgery rate after anterior or posterior cervical spinal surgery.

Surgical outcomes of degenerative cervical spinal disease are dependent on the selection of surgical techniques. Although a standardized decision cannot be made in an actual clinical setting, continued education is provided to standardize the medical practice among surgeons. Therefore, it is necessary to supervise and regularly update overall surgical outcomes. This study aimed to compare the rate of additional surgery between anterior and posterior surgeries for degenerative cervical spinal disease using the National Health Insurance Service-National Sample Cohort (NHIS-NSC) nationwide patient database. The NHIS-NSC is a population-based cohort with about a million participants. This retrospective cohort study included 741 adult patients (> 18 years) who underwent their first cervical spinal surgery for degenerative cervical spinal disease. The median follow-up period was 7.3 years. An event was defined as the registration of any type of cervical spinal surgery during the follow-up period. Event-free survival analysis was used for outcome analysis, and the following factors were used as covariates for adjustment: location of disease, sex, age, type of insurance, disability, type of hospital, Charles comorbidity Index, and osteoporosis. Anterior cervical surgery was selected for 75.0% of the patients, and posterior cervical surgery for the remaining 25.0%. Cervical radiculopathy due to foraminal stenosis, hard disc, or soft disc was the primary diagnosis in 78.0% of the patients, and central spinal stenosis was the primary diagnosis in 22.0% of them. Additional surgery was performed for 5.0% of the patients after anterior cervical surgery and 6.5% of the patients after posterior cervical surgery (adjusted subhazard ratio, 0.83; 95% confidence interval, 0.40-1.74). The rates of additional surgery were not different between anterior and posterior cervical surgeries. The results would be helpful in evaluating current practice as a whole and adjusting the health insurance policy.

Spin-wave duplexer studied by finite-element micromagnetic simulation.

We conceptually designed a robust nano-scale waveguide structure suitable for potential use as a spin-wave duplexer that allows signal propagation only of selected narrow-band frequencies and duplex transmission in a three-port device comprising a receiver, a transmitter, and their common antenna. The waveguide structure combines three different arms and a circular ring, both made of nanostrip waveguides and a single magnetic material for reliably controllable propagations of spin waves. We attribute the observed duplex transmission of spin waves of narrow pass bands to scattering of spin waves by edge solitons placed at contact areas between the arms and the circular ring. This work proposes the first concept of nano-scale magnonic duplexers operating beyond GHz-frequency ranges.

Intracranial neurenteric cyst arising at the suprasellar cistern with extension to middle cranial fossa.

INTRODUCTION: Intracranial neurenteric cysts are rare and are not often found in the supratentorial space. We present a case of an intracranial neurenteric cyst that arose at the suprasellar cistern with extension to the middle cranial fossa. HISTORY: A 3-year-old girl presented with seizure. Neuroimaging showed a huge extra-axial cyst involving the suprasellar cistern and left middle cranial fossa. Under the impression of an arachnoid cyst, she underwent fenestration of the cyst with basal cisterns and ventricle. The pathologic diagnosis was neurenteric cyst. Four years after the surgery, MRI showed no recurrence but did show poorly developed myelination of the left temporal white matter. Three years after surgery, seizures recurred. We consider epilepsy surgery in case of uncontrolled seizure. DISCUSSION: We discuss the unique case of supratentorially located neurenteric cyst that is just treated by fenestration. A close follow-up is needed for children with intracranial neurenteric cysts to surveil not only recurrence of lesion but also normal brain development.

Robust magnon-photon coupling in a planar-geometry hybrid of inverted split-ring resonator and YIG film.

We experimentally demonstrate strongly enhanced coupling between excited magnons in an Yttrium Iron Garnet (YIG) film and microwave photons in an inverted pattern of split-ring resonator (noted as ISRR). The anti-crossing effects of the ISRR's photon mode and the YIG's magnon modes were found from |S21|-versus-frequency measurements for different strengths and directions of externally applied magnetic fields. The spin-number-normalized coupling strength (i.e. single spin-photon coupling) [Formula: see text] was determined to 0.194 Hz ([Formula: see text] = 90 MHz) at 3.7 GHz frequency. Furthermore, we found that additional fine features in the anti-crossing region originate from the excitation of different spin-wave modes (such as the magnetostatic surface and the backward-volume magnetostatic spin-waves) rather than the Kittel-type mode. These spin-wave modes, as coupled with the ISRR mode, modify the anti-crossing effect as well as their coupling strength. An equivalent circuit model very accurately reproduced the observed anti-crossing effect and its coupling strength variation with the magnetic field direction in the planar-geometry ISRR/YIG hybrid system. This work paves the way for the design of new types of high-gain magnon-photon coupling systems in planar geometry.

Coupled gyration modes in one-dimensional skyrmion arrays in thin-film nanostrips as new type of information carrier.

We report on a micromagnetic numerical simulation study of dynamic coupling between neighboring skyrmions periodically arranged in narrow-width nanostrips. We explored the coupled gyration modes and their characteristic dispersions in terms of the interdistance between the neighboring skyrmions. The application of perpendicular magnetic fields allows for the control and modification of the dispersion of the coupled gyration modes. The coupled gyration modes of individual skyrmions might provide a new type of information carrier in narrow-width straight and curved nanostrips, as driven by magnetic interactions in such continuous thin films.