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Abstract 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.

Cervical spinal deformity (CSD) is a complex condition characterized by abnormal curvature and cervical spine alignment. It can lead to a multitude of symptoms, including chronic pain, neurological deficits, and functional impairments, severely impacting an individual’s health-related quality of life (HRQoL). Surgical intervention is often necessary to address the deformity and alleviate symptoms, but optimal surgical strategies remain a topic of ongoing research and debate. This narrative review aims to provide an in-depth overview of the surgical management of CSD, focusing on optimizing patient outcomes and enhancing readers’ understanding of the complexities involved. We begin by discussing the importance of preoperative assessment, including comprehensive radiographic evaluation and careful consideration of the global spinal alignment. The relationship between the cervical spine and the reciprocal changes that occur are explored to guide surgeons in their decision-making process. Furthermore, we delve into the selection of fusion levels, emphasizing the significance of identifying the primary driver of deformity. We review the current literature on optimal alignment targets and strategies to optimize surgical planning. By providing a comprehensive analysis of the surgical management of CSD, this review aims to enhance the readers’ knowledge and assist surgeons in making informed decisions when planning and executing surgical interventions. Understanding the intricacies of CSD correction and the latest advancements in the field can ultimately improve patient outcomes and enhance HRQoL for individuals suffering from this challenging condition.

Objective Multilevel or revisional posterior spinal surgery is prone to infection and delayed wound healing, related with the wound closure time and suture strength. Knotless barbed suture is an innovative self-locking, multianchor suture. This study aims to evaluate the safety and efficacy of the knotless barbed suture and self-adhering mesh with polymeric glue in multilevel or revisional posterior spinal surgery. Methods This is a single-center retrospective matched cohort study. Patients were divided into 2 groups based on the wound closure method: barbed suture group with novel wound closure, and conventional suture group with conventional wound closure, 1:1 matched by the level of surgery and sex, resulting in 120 subjects each. Total operation time and wound closure time were measured intraoperatively, and perioperative clinical outcome parameters including postoperative wound complication were investigated for the first 3 months postoperatively. The distribution of continuous variables was assessed for normality by Shapiro-Wilk test, then parametric or nonparametric tests were applied accordingly (paired t-test or Wilcoxon signed-rank test). Results Wound closure time was significantly shorter with the novel barbed suture than with conventional suture in all subgroups divided by the level of spinal surgery: 3–5, 6–9, ≥ 10 levels (p < 0.001). The 2 groups showed no significant differences in surgical complications (p = 1.000). Specially, total operation time and wound-closing time were significantly shorter in revisional subgroup. Conclusion Absorbable knotless barbed suture and self-adhering mesh with polymeric glue can shorten spinal wound closure time with noninferiority in complications for multilevel or revisional spinal surgery.

Adolescent idiopathic scoliosis (AIS) affects approximately 2% of adolescents across all ethnicities. The objectives of surgery for AIS are to halt curve progression, correct the deformity in 3 dimensions, and preserve as many mobile spinal segments as possible, avoiding junctional complications. Despite ongoing development in algorithms and classification systems for the surgical treatment of AIS, there is still considerable debate about selecting the appropriate fusion level. In this study, we review the literature on fusion selection and present current concepts regarding the lower instrumented vertebra in the selection of the fusion level for AIS surgery.

The idea of the global balance of spine stems from Jean Dubousset, who first introduced the concept of cone of economy. Through the compensatory mechanisms, the human body maintains an upright posture and horizontal gaze in the setting of the spinal malalignment. Compensation takes place not only in the mobile spine segments, but also in the pelvis and lower extremities. Patients with a malalignment exhibit compensatory changes in the cervical hyper-lordosis, posterior pelvic shift, knee/ankle flexion, hip extension, and the pelvic retroversion. The advent of whole-body stereo radiography has yielded an improved understanding of global changes among the patients. Deformity-induced compensatory changes in the sagittal alignment could be resolved reciprocally after the surgical correction of the malalignment. Thoracolumbar realignment surgery restores the pathologic compensatory changes in the unfused spinal segments, pelvis, and the lower extremities. Similarly, reciprocal changes in the thoracolumbar spine may harmonize global sagittal alignment after the cervical reconstruction. This study reviews the compensatory mechanisms and reciprocal changes in global sagittal alignment caused by the surgical correction and highlights, the factors that should be considered while assessing a patient’s compensatory status.

Over the last few decades, the importance of the sagittal plane and its contour has gained significant recognition. Through full-body stereoradiography, the understanding of compensatory mechanisms, and the concept of global balance and reciprocal change has expanded. There have been a few reports describing how cervical realignment surgery affects global spinal alignment (GSA) and global balance. Despite the research efforts, the concept of reciprocal change and global balance is still perplexing. Understanding the compensatory status and main drivers of deformity in a patient is vital because the compensatory mechanisms may resolve reciprocally following cervical realignment surgery. A meticulous preoperative evaluation of the whole-body alignment, including the pelvis and lower extremities, is paramount to appreciate optimal GSA in the correction of spinal malalignment. This study aims to summarize relevant literature on the reciprocal changes in the whole body caused by cervical realignment surgery and review recent perspectives regarding cervical compensatory mechanisms.

Objective C2 slope (C2S), a cervical parameter mathematically approximated as T1 slope minus cervical lordosis (T1S–CL), predicts functional improvement in cervical deformity patients. Nonetheless, C2S is a positional parameter based only on the horizontal axis. The current study aims to introduce novel odontoid parameters and establish their relationships with patient-reported health-related quality of life (HRQoL). Methods Lateral plain radiographs of 32 adults who underwent multilevel posterior cervical fusion were analyzed. The odontoid parameters included odontoid incidence (OI), C2S, odontoid tilt (OT), and gravity line-C2 distance (GL-C2), while the cervical parameters were the Cobb angle at C0–1, C1–2, C0–2, C2–7, C2–7 sagittal vertical axis (cSVA), T1 slope, and T1S–CL. The range of motion (ROM) of the occipito-atlantoaxial complex was measured in flexion and extension plain radiographs. Scores on the Neck Disability Index (NDI) and visual analogue scale (VAS) for axial neck (VASn) and arm pain were measured. Results Compared to asymptomatic subjects, patients had larger C2S, cSVA, and T1S–CL, and smaller OT. Preoperatively, OI was significantly correlated with the ROM of C1–2 (r = 0.37, p < 0.05) and C0–2 (r = 0.46, p < 0.01). OT and C2S had significant correlations with the C0–1, C1–2, and C0–2 angles, GL-C2, and T1S–CL. Postoperative NDI scores were significantly correlated with OI (r = -0.40, p < 0.05) and OT (ρ = -0.37, p < 0.05). VASn was significantly correlated with GL-C2 (r = -0.35, p < 0.05). Conclusion The odontoid parameters were significantly correlated with established cervical parameters and HRQoL measures. OI is a constant parameter representing the individual's compensatory reservoir at the upper cervical spine.

Objective This study is an investigator-initiated, prospective, randomized, controlled study to evaluate the efficacy and safety of the combined use of recombinant human BMP-2 (rhBMP-2) and a hydroxyapatite (HA) carrier in multilevel fusion in patients with adult spinal deformity (ASD). Methods Thirty patients underwent posterolateral fusion for lumbar spinal deformities at 3 to 5 segments between L1 and S1. The patients received rhBMP-2+HA or HA on the left or right side of the transverse processes. They were followed up regularly at 1, 3, 6, and 12 months postoperatively. Fusion was defined according to the bone bridging on computed tomography scans. The fusion rate per segment was subanalyzed. Function and quality of life as well as pain in the lower back and lower extremities were evaluated. Results The union rate for the rhBMP-2+HA group was 100% at 6 and 12 months. The union rate for the HA group was 77.8% (21 of 27) at 6 months and 88.0% (22 of 25) at 12 months (p = 0.014 at 6 months; not significant at 12 months). All segments were fused at 6 and 12 months in the rhBMP-2+HA group (p < 0.001). In the HA group, 108 of 115 segments (93.5%) were fused at 6 months and 105 of 109 segments (96.3%) at 12 months. Other clinical parameters (visual analogue scale, 36-item Short Form Health Survey, and Scoliosis Research Society-22 scores) improved compared to baseline. Conclusion Combining rhBMP-2 and an HA carrier is a safe and effective method to achieve multilevel fusion in patients with ASD.

Abstract Base treatment and metal doping were evaluated as means of enhancing the photocatalytic activity of ZrO2 nanoparticles (NPs) via the generation of oxygen vacancies (OvS), and the sites responsible for this enhancement were identified and characterized by spectroscopic and microscopic techniques. We confirmed that OvS produced by base treatment engaged in photocatalytic activity for organic pollutant degradation, whereas surface defects introduced by Cr-ion doping engaged in oxidative catalysis of molecules. Moreover, we verified that base-treated ZrO2 NPs outperformed their Cr-ion doped counterparts as photocatalysts using in situ X-ray photoelectron spectroscopy and scanning transmission electron microscopy coupled with electron energy loss spectroscopy (STEM-EELS). Thus, our study provides valuable information on the origin of the enhanced photocatalytic activity of modified ZrO2 NPs and demonstrates the practicality of in situ spectroscopy and STEM-EELS for the evaluation of highly efficient metal oxide photocatalysts.

Objective By using angulation of the axis itself, this study aims to define and analyze odontoid incidence (OI) and odontoid tilt (OT) as novel cervical alignment parameters and investigate their correlations with cervical alignment. Methods Novel and existing parameters were measured with whole-spine lateral plain radiographs and EOS images of 42 adults without cervical symptoms. The correlations of OI, OT, C2 slope (C2S), and T1 slope (T1S) were calculated. Results The OI, OT, and C2S showed significant correlations with C2–7 angle (r = 0.43, r = -0.42, r = 0.62, respectively) and C0–2 angle (r = -0.33, r = 0.48, r = -0.61, respectively). OI, OT, T1S were independent predictors of the C2–7 angle in univariate regression analysis (adjusted-R2 = 0.17, R2 = 0.15, R2 = 0.28, respectively). OI, OT, and T1S were independent predictors in the multivariable regression analysis with estimated standardized coefficients of 0.36, -0.67, -0.69, respectively (adjusted- R2 = 0.80, p < 0.001). Regarding the C0–2 angle, OI and OT were independent predictors in the univariate regression analysis (adjusted-R2 = 0.08, R2 = 0.21, respectively). Conclusion OI, OT, and C2S had significant correlations with cervical alignment. As the pelvic incidence, the OI is the only anatomical and constant parameter that could be used as a reference point related to the cervical spine from the rostral end. The study results may serve as baseline data for further studies on the alignment and balance of the cervical spine.

Objective To determine whether the last touched vertebra (LTV) on supine radiographs is suitable for the lower instrumented vertebra (LIV) in adolescent idiopathic scoliosis (AIS) correction surgery. Methods In total, 57 patients were included in the study following posterior instrumentation and fusion. The average follow-up period was 2.2 years. Patients were classified into 4 groups according to the relationship of the location of LIV, LTV, and the last substantially touched vertebra (LSTV) on upright radiographs and the LTV on supine radiographs. In group 1, the upright LTV and supine LTV were the same. Group 1 was subdivided into group 1A and group 1B according to whether the LTV and LSTV were different or the same, respectively. In group 2, the upright LTV was selected as the LIV, whereas in group 3, the supine LTV was selected as the LIV. The baseline characteristics and the preoperative and postoperative radiographic/clinical outcomes of the groups were analyzed. Results No differences were found in the preoperative clinical and radiographic baseline characteristics of the 4 groups except the LIV-central sacral vertical line distance. The immediate, 6-month, 1-year, and 2-year postoperative outcomes were not significantly different among the 4 groups. One patient (4.3%) in group 1A experienced radiographic adding-on without clinical symptoms. No patients underwent revision surgery. Conclusion The group in whom the LIV was selected as the LTV on supine x-rays showed similar postoperative radiographic and clinical results to other groups. The LTV on preoperative supine radiographs is acceptable as the LIV in AIS surgery to maximize motion segments.

Objective: This study sought to investigate the utility of intraoperative neurophysiological monitoring (IONM) in the surgical treatment for spinal arteriovenous malformations (SAVMs). Methods: We retrospectively reviewed the data of 39 patients who underwent surgical treatment for SAVMs. Twenty-eight patients who received multimodal IONM (transcranial electrical motor-evoked potentials [MEPs], somatosensory-evoked potentials, continuous electromyography, and bulbocavernosus reflex [BCR]) between 2011 and 2020 were compared to 11 historical controls between 2003 and 2011. The rates of postoperative neurological deficits (PNDs), neurophysiological warnings, and their characteristics were analyzed. Results: PNDs were developed in 10.7% and 54.5% of patients in the IONM and historical control (non-IONM) groups, respectively (p = 0.008). Moreover, not applying IONM was the only significant risk factor for the development of PNDs in the logistic regression analysis (odds ratio 10.0, p = 0.007). In the IONM group, a total of three electrophysiological warnings were observed, and two of these were true positives; one patient complained of leg motor weakness after surgery with loss of the abductor halluces MEPs. The other patient experienced disappearance of the BCR during surgery and newly developed urinary retention. Overall, the sensitivity, specificity, positive predictive value, and negative predictive value of IONM warnings for detecting PNDs were 66.7%, 96.0%, 66.7%, and 96.0%, respectively. Conclusions: The neurological outcome of the IONM group was significantly better than that of the historical control group in the surgical treatments for SAVMs. Significance: Multimodal IONM could be a useful tool to detect neurological damage with relatively high accuracy in this type of surgery.

Abstract Radiotherapy has played an important role in the treatment of spinal metastases. One of the major complications of radiotherapy is vertebral compression fracture (VCF). Although the spinal instability neoplastic score (SINS) was developed for evaluating spinal instability in patients with spinal metastases, it is also commonly used to predict VCF after radiotherapy in patients with spinal metastases. However, its accuracy for predicting radiotherapy-induced VCF and precision remain controversial. The aim of this study was to clarify the diagnostic value of the SINS to predict radiotherapy-induced VCF and to make recommendations for improving its diagnostic power. We searched core databases and identified 246 studies. Fourteen studies were analyzed, including 7 studies (with 1269 segments) for accuracy and 7 studies (with 280 patients) for precision. For accuracy, the area under the summary receiver operating characteristic curve was 0.776. When a SINS cut-off value of 7 was used, as was done in the included studies, the pooled sensitivity was 0.790 and the pooled specificity was 0.546. For precision, the summary estimate of interobserver agreement was the highest dividing 2 categories based on a cut-off value of 7, and the value was 0.788. The body collapse showed moderate relationship and precision with the VCF. The lytic tumor of bone lesion showed high accuracy and fair reliability, while location had excellent reliability, but low accuracy. The SINS system can be used to predict the occurrence of VCF after radiotherapy in spinal metastases with moderate accuracy and substantial reliability. Increasing the cut-off value and revising the domains may improve the diagnostic performance to predict the VCF of the SINS.

Abstract Physicians often encounter surgical candidates with lumbar disc herniation (LDH) who request non-surgical management even though surgery is recommended. However, second opinions may differ among doctors. Therefore, a prospective comprehensive cohort study (CCS) was designed to assess outcomes of nonsurgical treatment for surgical candidates who were recommended to undergo surgery for LDH but requested a second opinion. The CCS includes both randomized and observational cohorts, comprising a nonsurgery cohort and surgery cohort, in a parallel fashion. Crossover between the nonsurgery and surgery cohorts was allowed at any time. The present study was an as-treated interim analysis of 128 cases (nonsurgery cohort, n = 71; surgery cohort, n = 57). Patient-reported outcomes included visual analogue scores for the back (VAS-B) and leg (VAS-L), the Oswestry Disability Index, the EuroQol 5-Dimension instrument, and the 36-Item Short-Form Health Survey (SF-36), which were evaluated at baseline and at 1, 3, 6, 12, and 24 months. At baseline, age and SF-36 physical function were significantly lower in the surgery cohort than in the nonsurgery cohort (p 0.01). Nonsurgical management may be a negotiable option even for surgical candidates in the shared decision-making process.

Objective: This study aimed to investigate the value of intraoperative neurophysiological monitoring (IONM) in anterior cervical spine discectomy with fusion (ACDF) for ossification of the posterior longitudinal ligament (OPLL). Methods: Patients who underwent multimodal IONM (transcranial electrical motor-evoked potentials [tcMEP], somatosensory-evoked potentials, and continuous electromyography) for ACDF from 2009 to 2019 were compared to historical controls from 2003 to 2009. The rates of postoperative neurological deficits, neurophysiological warnings, and their characteristics were analyzed. Results: Among 196 patients, postoperative neurological deficit rates were 3.79% and 14.06% in the IONM and historical control (non-IONM) groups, respectively (p

When spinal imbalance occurs, the human body reacts through various compensatory mechanisms to maintain the head over the pelvis and to retain a horizontal gaze. These compensations occur through mobile spine segments as well as pelvic tilt and lower extremities. The purpose of this review was to understand the surgical impact on global sagittal alignment and health-related quality of life (HRQoL) following cervical kyphosis correction surgery. The cervical kyphosis correction surgery induces reciprocal changes in craniocervical and thoracolumbar alignment. Successful cervical deformity correction needs to focus not only on restoring proper cervical lordosis, but also on achieving global balance of the cervical spine with other parts of the spine. The goal of the surgery is to achieve occiputtrunk (OT) concordance (the center of gravity-C7 sagittal vertical axis < 30 mm) and cervical sagittal balance. Once OT-concordance is achieved, subsequent thoracolumbar alignment changes occur as needed to harmonize global spinal alignment. Reciprocal changes after surgery exhibit different patterns depending on whether patients have compensation ability in their thoracolumbar spine or not. C2–7 sagittal vertical axis and sagittal morphotype of the cervical kyphosis are correlated with HRQoL. Changes in cervical lordosis minus T1 slope correlate to HRQoL improvements.

Objective To examine the biomechanical stress distribution at the upper instrumented vertebra (UIV) according to unicortical- and bicortical purchase model by finite element analysis (FEA). Methods A T8 to Sacrum with implant finite element model was developed and validated. The pedicle screws were unicortically or bicortically inserted from T10 to L5, and each model was compared and the von Mises (VM) yield stress of T10 was calculated. According to the motion (flexion, extension, lateral bending, and axial rotation) of spine, boundary condition values were set as 15°, 15°, 10°, 4°. Results Although the 2 stress values did not show a significant difference between the unicortical- and bicortical purchase models in the flexion and extension, bicortical purchase model showed a larger stress distribution. However, the asymmetric behavior was significantly greater in the case of lateral bending (0.802 MPa vs. 0.489 MPa) and the rotation (5.545 MPa vs. 4.905 MPa). The greater stress was observed on the spinal body surface abutting the implanted screw. Although the maximum stress was observed around the implanted screw in the bicortical purchase model under axial loading, the VM stress of both models was not significantly different. Conclusion Bicortical purchase model showed a larger stress distribution than the unicortical model, especially in the case of lateral bending and the rotation behavior. Our biomechanical simulation by FEA indicates that bicortical fixation at UIV can be a risk factor for early UIV compression fracture after adult spinal deformity surgery.

Abstract The coverage and temperature dependence of ZIRLO cladding with H2O adsorption are studied using synchrotron-based high-resolution photoemission spectroscopy (HRPES). Based on the analytical results of the Zr 3d, O 1 s, C 1 s, and Sn 3d HRPES profiles prior to H2O adsorption, we determine the surface compositions of O2−, hydroxyl OH−, chemisorbed H2O, zirconium carbide, adventitious carbon, Sn metal, and SnO2 in ZIRLO. When ZIRLO is exposed to H2O molecules, the relative proportion of zirconium metal decreases, whereas that of the total zirconium oxides increases, suggesting the reaction between H2O and the zirconium metal in ZIRLO. On annealing a sample with 1000 L H2O on ZIRLO at 300 °C, Zr2O3 and ZrO2 decompose, and oxygen diffuses into the bulk, thereby reducing the oxidation states of zirconium on the surface. Moreover, at this temperature, the excess H2O molecules on ZIRLO are thoroughly desorbed and tin element is diffused into the bulk in ZIRLO.

Objective C5 palsy is a severe complication after cervical spine surgery, the pathophysiology of which remains unclear. This multicenter study investigated the incidence of C5 palsy following cervical spine surgery in Korea. Methods We conducted a retrospective multicenter study involving 21 centers from the Korean Cervical Spine Study Group. The inclusion criteria were cervical spine surgery patients between 2012 and 2016, excluding cases of neck surgery. In patients with C5 palsy, the operative methods, disease category, onset time of C5 palsy, recovery time, C5 manual muscle testing (MMT) grade, and post-C5 palsy management were analyzed. Results We collected 15,097 cervical spine surgery cases from 21 centers. C5 palsy occurred in 88 cases (0.58%). C5 palsy was more common in male patients (p=0.019) and after posterior approach procedures (p

Abstract Herein, graphite is proposed as a reliable Ca2+‐intercalation anode in tetraglyme (G4). When charged (reduced), graphite accommodates solvated Ca2+‐ions (Ca‐G4) and delivers a reversible capacity of 62 mAh g−1 that signifies the formation of a ternary intercalation compound, Ca‐G4·C72. Mass/volume changes during Ca‐G4 intercalation and the evolution of in operando X‐ray diffraction studies both suggest that Ca‐G4 intercalation results in the formation of an intermediate phase between stage‐III and stage‐II with a gallery height of 11.41 Å. Density functional theory calculations also reveal that the most stable conformation of Ca‐G4 has a planar structure with Ca2+ surrounded by G4, which eventually forms a double stack that aligns with graphene layers after intercalation. Despite large dimensional changes during charge/discharge (C/D), both rate performance and cyclic stability are excellent. Graphite retains a substantial capacity at high C/D rates (e.g., 47 mAh g−1 at 1.0 A g−1 s vs 62 mAh g−1 at 0.05 A g−1) and shows no capacity decay during as many as 2000 C/D cycles. As the first Ca2+‐shuttling calcium‐ion batteries with a graphite anode, a full‐cell is constructed by coupling with an organic cathode and its electrochemical performance is presented.

Purpose To present the typical and atypical magnetic resonance image (MRI) findings of intramedullary spinal ependymomas, and compare these findings with pathological subtypes. Materials and Methods Between January 2003 to November 2014, 47 patients who had spinal ependymoma with pathologic confirmation, were retrospectively reviewed with all electronic medical records and MR images. MR imaging was done in all cases, and the images of spinal ependymomas and associated enhancement patterns were correlated with pathologic findings. Results The enhancement patterns were categorized into four categories: homogeneous, heterogeneous, rim-enhancement, and non-enhancement. Heterogeneous enhancement was observed in 50% of the cases. Among the 47 cases, 35 cases were well-marginated, with 21 being cervically located. All lesions were centrally located in the axial axis. Most of the cases showed T1-iso signal intensity (81%) and T2-high signal intensity (72%). The hemosiderin cap sign, syringomyelia, tumoral and non-tumoral cysts were well demonstrated. The most common pathologic type was cellular ependymoma. However, due to the small sample size, we believe it inappropriate to statistically discuss the MRI findings according to the pathologic subtype. Conclusion Most spinal ependymoma showed T1-iso signal intensity and T2-high signal intensity, with enhancement patterns other than homogeneous enhancement.

Objective: Motor evoked potentials (MEPs) changes might be caused to the non-surgically induced factors during cervical spinal surgery. Therefore, control MEPs recorded cranially to the exit of the C5 root are highly recommendable in cervical spinal surgery. We studied whether corticobulbar MEPs (C-MEPs) from tongue muscle could be used as a control MEPs in cervical spinal surgery. Methods: Twenty-five consecutive cervical spinal surgeries were analyzed. Stimulation of motor area for tongue was done by subcutaneous electrodes placed at C3/C4 (10–20 EEG System), and recording was done from both sides of tongue. Results: C-MEPs were recorded successfully 24 out of the 25 (96%) tested patients. Forty-six out of fifty MEPs (92%) from tongue muscles were monitorable from the baseline. In two patients, we could obtain only unilateral C-MEPs. Mean MEPs latencies obtained from the left and right side of the tongue were 11.5 ± 1 ms and 11.5 ± 0.8 ms, respectively. Conclusions: Monitoring C-MEPs from tongue muscles might be useful control in cervical spinal surgery. They were easily elicited and relatively free from phenomenon of peripheral stimulation of the hypoglossal nerves. Significance: This is first study to identify the usefulness of C-MEPs as a control of cervical spinal surgery. Keywords: Intraoperative neurophysiological monitoring, Motor-evoked potential, Corticospinal tract, Corticobulbar MEPs, Hypoglossal nerve

Objectives: Anterior cervical discectomy and fusion (ACDF) surgery is the most common surgical procedure for the cervical spine with low complication rate. Despite the potential prognostic benefit, intraoperative neurophysiological monitoring (IONM), a method for detecting impending neurological compromise, is not routinely used in ACDF surgery. The present study aimed to identify the potential benefits of monitoring multi-channel motor evoked potentials (MEPs) during ACDF surgery. Methods: We retrospectively reviewed 200 consecutive patients who received IONM with multi-channel MEPs and somatosensory evoked potentials (SSEPs). On average, 9.2 muscles per patient were evaluated under MEP monitoring. Results: The rate of MEP change during surgery in the multi-level ACDF group was significantly higher than the single-level group. Two patients from the single-level ACDF group (1.7%) and four patients from the multi-level ACDF group (4.9%) experienced post-operative motor deficits. Multi-channel MEPs monitoring during single and multi-level ACDF surgery demonstrated higher sensitivity, specificity, positive predictive and negative predictive value than SSEP monitoring. Conclusions: Multi-channel MEP monitoring might be beneficial for the detection of segmental injury as well as long tract injury during single- and multi-level ACDF surgery. Significance: This is first large scale study to identify the usefulness of multi-channel MEPs in monitoring ACDF surgery. Keywords: Disc disease, Somatosensory evoked potentials, Intraoperative neurophysiological monitoring, Motor evoked potentials, Anterior cervical discectomy and fusion

In this study, single-crystalline and poly-crystalline CrCoNi alloys are utilized as model systems to analyze the distinct roles of each GB and interstitial lattice sites. To effectively reveal hydrogen behavior, both electrochemical and gaseous hydrogen pre-charging methods are applied. Hydrogen content, diffusivity, and trap behaviors are quantified using thermal desorption analysis and hydrogen permeation tests, which determines (1) changes in hydrogen behavior depending on the presence of GB and (2) alterations in hydrogen behavior depending on lattice crystallographic orientation. The results indicate that GB and interstitial lattice sites exhibit comparable binding energies for hydrogen trapping. However, the introduction of GB alters the primary trapping sites from interstitial lattice sites to GB. In this case, the hydrogen content in the poly-crystalline alloy is determined by the trap site density of the primary trapping site. On the other hand, in the single-crystalline alloy, where only interstitial lattice sites exist, the crystallographic orientation of the hydrogen-charged plane is an important variable that determines hydrogen content and hydrogen diffusivity. Such insights contribute to a deeper understanding of hydrogen behavior within a more intricate microstructure, suggesting the alloy design approach to enhance resistance to HE.

Iatrogenic spinal cord herniation is a rare complication following spinal surgery. We introduce a posterior trans-dural repair technique used in a case of thoracic spinal cord herniation through a ventral dural defect following resection of ossification of the posterior longitudinal ligament (OPLL) in the cervicothoracic spine. A 51-year-old female was suffering from paraplegia after laminectomy alone for cervicothoracic OPLL. Magnetic resonance imaging revealed a severely compressed spinal cord with pseudomeningocele identified postoperatively. Cerebrospinal fluid leak and iatrogenic spinal cord herniation persisted despite several operations with duroplasty and sealing agent. Finally, the problems were treated by repair of the ventral dural defect with posterior trans-dural duroplasty. Several months after surgery, the patient could walk independently. This surgical technique can be applied to treat ventral dural defect and spinal cord herniation.

Study DesignA retrospective cross-sectional study.PurposeThe purpose of this study is to evaluate the accuracy and safety of free-hand pedicle screw insertion performed by a young surgeon.Overview of LiteratureFew articles exist regarding the safety of the free-hand technique without inspection by an experienced spine surgeon.MethodsThe index surgeon has performed spinal surgery for 2 years by himself. He performed fluoroscopy-assisted pedicle screw installation for his first year. Since then, he has used the free-hand technique. We retrospectively reviewed the records of all consecutive patients undergoing pedicle screw installation using the free-hand technique without fluoroscopy in the thoracic or lumbar spine by the index surgeon. Incidence and extent of cortical breach by misplaced pedicle screw was determined by a review of postoperative computed tomography (CT) images.ResultsA total of 36 patients received 306 free-hand placed pedicle screws in the thoracic or lumbar spine. A total of 12 screws (3.9%) were identified as breaching the pedicle in 9 patients. Upper thoracic spine was the most frequent location of screw breach (10.8%). Lateral breach (2.3%) was more frequent than any other direction. Screw breach on the right side (9 patients) was more common than that on the left side (3 patients) (p

Background: Despite the firmly established occupational risk of exposure to X-rays, they are used extensively in spine surgeries. Shielding by lead aprons is the most common protective practice. We quantified the level of their radiation blocking ability in a real-life setting. Methods: Single-center, prospective, randomized study of adult patients with degenerative lumbar disorders, scheduled to undergo posterior lumbar interbody fusion. Instrumentation was performed in either a robot-assisted, minimally invasive approach (RO) or a conventional, fluoroscopically-assisted, open approach (FA). Outcome measures included the quantitative measurement of the surgeon’s actual exposure to radiation, as recorded by thermo-luminescent dosimeters (TLD) worn both above and under the 0.5 mm thyroid and trunk lead protectors. Findings: Sixty four patients were included in this study, 34 in the RO cohort and 30 in the FA cohort. The radiation blocked by the aprons, represented as the ratio of the under-apron to above-apron TLDs, averaged 37.1% (range 25.4–48.3%, 95% confidence interval between 30.6–43.6%). In the RO cohort, the average per-screw radiation dose and time were 51.9% and 73.7% lower, respectively, than the per screw exposure in the FA cohort. Interpretation: The 0.5 mm lead aprons blocked just over one third of the radiation scattered towards the surgeon. Use of robotic-guidance in a minimally invasive approach provided for a reduction of 62.5% of the overall radiation the surgeon was exposed to during open conventional approach. We conclude that reduced radiation use (e.g. by using robotic guidance) is a more effective strategy for minimizing exposure to radiation than reliance on protection by lead aprons, and recommend utilization of practices and technologies that reduce the surgical team’s routine exposure to X-rays.

Background: The diagnosis rate of adult spinal deformity (ASD) is increasing with increased life expectancy and the prevalence of degenerative spinal diseases. The prevalence of ASD in adults aged >60 years has been reported to be up to 68%. ASD has significant impact on the pain, disability, and mental health. Therefore, it is necessary to establish an effective surgical plan by accumulating modern knowledge on ASD, developing surgical techniques, and improving pre- and post-operative care so as to achieve optimal surgical outcomes. Current Concepts: ASD results from coronal and sagittal malalignments caused by degenerative diseases or iatrogenic factors. Recently, the significance of sagittal alignment correction has been emphasized, and the SRSSchwab classification of ASD is generally accepted. Individualized correction goals can be set through sufficient preoperative evaluations and imaging studies, and appropriate coronal and sagittal alignment correction can be achieved through intraoperative positioning of patient, anterior and posterior approach spine surgery, screw fixation, and osteotomies. Discussion and Conclusion: It is necessary to establish an optimal correction target and select the appropriate surgical approach for each patient with ASD, so as to improve patients' quality of life. Surgical interventions for ASD can be safely completed by adequately comprehending and anticipating perioperative complications. [ABSTRACT FROM AUTHOR]

The purpose of this review was to synthesize the research on global spinal alignment and reciprocal changes following cervical or thoracolumbar reconstruction surgery. We carried out a search of PubMed, EMBASE, and Cochrane Library for studies through May 2020, and ultimately included 11 articles. The optimal goal of a truly balanced spine is to maintain the head over the femoral heads. When spinal imbalance occurs, the human body reacts through various compensatory mechanisms to maintain the head over the pelvis and to retain a horizontal gaze. Historically, deformity correction has focused on correcting scoliosis and preventing scoliotic curve progression. Following substantial correction of a spinal deformity, reciprocal changes take place in the flexible segments proximal and distal to the area of correction. Restoration of lumbar lordosis following surgery to correct a thoracolumbar deformity induces reciprocal changes in T1 slope, cervical lordosis, pelvic shift, and lower extremity parameters. Patients with cervical kyphosis exhibit different patterns of reciprocal changes depending on whether they have head-balanced or trunk-balanced kyphosis. These reciprocal changes should be considered to in order to prevent secondary spine disorders. We emphasize the importance of evaluating the global spinal alignment to assess postoperative changes. [ABSTRACT FROM AUTHOR]

Objective : Expansion in the spinal canal area (SCA) after laminoplasty is one of the critical factors to relieve the preoperative symptoms. No previous study has compared the increases in SCA achieved by open-door laminoplasty (ODL) and double door laminoplasty (DDL) according to the preoperative lamina angle (LA). This study was designed to clarify the relationship between the laminoplasty opening angle (OA)/laminoplasty opening size (OS) and increases in the SCA following ODL and DDL according to the preoperative LA using a simulation model. Methods : The simulation model was constructed and validated by comparing the clinical data of 64 patients who had undergone C3-C6 laminoplasty (43 patients with ODL and 21 patients with DDL). SCA expansion was predicted with a verified simulation model at various preoperative LAs (from 28° to 32°) with different OAs (40° to 44°) and OSs (10 mm to 14 mm) recruited from patient data. Results : The constructed simulation model was validated by comparing clinical data and revealed a very high degree of correlation (r=0.935, p<0.001). In this validated model, at the same OA, the increase in SCA was higher following ODL than following DDL in the usual LA (p<0.05). At the same OS, the increase in SCA was slightly larger following DDL than following ODL, but the difference was not significant (p>0.05). The difference was significant when the preoperative LA was narrower or much wider. Conclusion : Based on clinical data, a simulation model was constructed and verified that could predict increases in the SCA following ODL and DDL. When applying this model, prediction in SCA increase using the OS parameter was more practical and compatible with clinical data. Both laminoplasties achieved enough SCA, and there was no significant difference between them in the usual range. [ABSTRACT FROM AUTHOR]

Objectives : The purpose of this study was to evaluate surgical outcomes and complications of spinal deformity associated with neurofibromatosis type-1 (NF-1). Methods : From 2012 to 2018, patients suffering from spinal deformity associated with NF-1 who underwent surgical correction were identified. Demographic data and radiographic measures were retrospectively reviewed. Pre- and postoperative whole spine radiograph images were used to determine both coronal and sagittal Cobb angles. All of patients underwent 3-dimentional computed tomographic scan and magnetic resonance imaging scan to confirm dystrophic features. For evaluation of clinical outcomes, we surveyed the pre- and postoperative scoliosis research society-22r (SRS-22r) score. Results : Seven patients with spinal deformity associated with NF-1 were enrolled in this study. The mean age of patients was 29.5±1.2 years old. The mean follow-up period was 2.8±1.4 years. The apex of the deformity was located in cervicothoracic (n=1), thoracic (n=4), and lumbar region (n=2). Most patients have poor bone quality and decreased bone mineral density with average T-score of -3.5±1.0. All patients underwent surgical correction via posterior approach. The pre- and postoperative mean coronal and sagittal Cobb angle was 61.6±22.6° and 34.6±38.1°, 56.8±18.5° and 40.2±9.1°, respectively. Mean correction rate of coronal and sagittal angle was 44.7% and 23.1%. Ultimate follow-up SRS-22r score (average score, 3.9±0.4) improved comparing to preoperative score (average score, 3.3±0.9). Only one patient received revision surgery due to rod fracture. No serious complication occurred, such as neurological deficit, and viscerovascular injury. Conclusion : The surgical correction of patients having spinal deformity associated with NF-1 is challenging, however the radiographic and clinical outcomes are satisfactory. The all posterior approach can be a safe and effective surgical option for patients having dystrophic curves associated with NF-1. [ABSTRACT FROM AUTHOR]