Enhancing the Evaluation System of Training Hospitals for Neurosurgical Residency Training and Education in South Korea : Striving for Balanced Participation and Differentiation.

The Korean Neurosurgical Society, with its 62 years of history, has witnessed substantial growth in the field of neurosurgery, producing over 3,400 neurosurgeons, establishing 12 divisions and 9 regional branches, and advancing in clinical management, diagnostic methods and academic research. Despite these developments, the regulations governing neurosurgical training and evaluation methods for training hospitals have remained largely unchanged, necessitating comprehensive revisions in response to evolving medical environments. To provide balanced participation opportunities for neurosurgery residents, the Korean Neurosurgical Society formed the Training Status Investigation Standard Change Task Force (TF Team) under the Training Education Committee. This paper presents the TF Team's findings and proposals for revising training status investigation standards and evaluation criteria. Through the processes including a lot of team meetings, workshops, education programs, official communications with 12 division societies, benchmarking from other societies and analysis of encrypted data from the past 5 years for neurosurgical training hospitals, the TF Team created a revised training status investigation proposal, supplemented main surgery criteria. And we applied this revised proposal to the training status investigation data collected from training hospitals in 2022 for simulation. We reduced the score for main surgeries to 10 points, introduced core competency surgery standards, allocating 5 points each for brain core competency surgery and spine and peripheral core competency surgery, for a total of 10 points. We also adjusted the major surgery score to 13 points, expanding the total surgery index score to 33 points. We introduced additional definitions for main surgeries in the areas of spine, pediatrics, and functional surgery. The equipment score was reduced from 17 points to 9 points. We specified minimum requirements for resident allocation eligibility, and if a hospital meets all of these criteria, they become eligible to apply for resident allocation. We introduced a new bonus point system for hospitals performing mechanical thrombectomy or stenting and peripheral nerve. The proposed revisions aim to improve the training and education of neurosurgical residents and overall neurosurgical care in Korea by creating a balanced and differentiated evaluation system for training hospitals. Further monitoring, communication, and adjustments are crucial for successful implementation.

Evaluating the Efficacy and Safety of Hemofence (Thorombin Cross-linked Sodium Hyaluronate Gel Matrix) in Hemostasis for Intractable Exudative Bleeding in Spinal Surgery: A Multicenter, Randomized, Phase III Clinical Trial.

Objective: To demonstrate the non-inferiority of the novel hemostatic agent, Hemofence® (BMI Korea Co. Ltd., Jeju Korea, thrombin cross-linked sodium hyaluronate gel matrix) compared to the established agent, Floseal Hemostatic Matrix (Baxter, thrombin-gelatin matrix) in achieving hemostasis for spinal surgeries, with secondary objectives to assess additional efficacy and safety. Methods: This clinical trial was a multicenter, randomized, subject-blinded, active-controlled, parallel-group, phase 3 study. Investigational drugs were administered to the first and second bleeding sites of each participant (or only to the first site if a second site was absent), evaluating hemostasis success rate within 10 minutes and the time to achieve hemostasis. Subsequent visits were conducted for safety assessments. For non-inferiority test, a 97.5% one-sided confidence interval was used; the test group was deemed non-inferior if the lower limit exceeded -10%. Results: This trial showed a 97.10% success rate in the test group and 96.05% in the control group for primary efficacy. The 95% confidence interval (-4.90%, 7.44%) confirmed the test drug's non-inferiority. Time to hemostasis showed no significant difference between groups. All adverse events, adverse drug reactions, and serious adverse events were statistically similar between groups (p=1.0000, p=0.2427, and p=0.9663, respectively). Conclusion: A novel hemostatic agent, Hemofence®, demonstrated an efficacy and safety profile comparable to that of Floseal.

Postoperative survival after lumbar instrumented surgery for metastatic spinal tumors: a nationwide population-based cohort analysis.

BACKGROUND: It is difficult to predict the expected survival after lumbar instrumented surgery for metastases owing to the difference among different cancer origins and the relatively short survival after surgery. AIMS: The aim of this study is to analyze the postoperative survival period of lumbar spinal metastasis patients who underwent lumbar instrumented surgery. METHODS: Data were collected from the Korean National Health Insurance Review and Assessment Service database. Patients who underwent lumbar spinal surgery with instrumentation between January 2011 and December 2015 for metastatic lumbar diseases were reviewed. The mean postoperative survival period of patients with metastatic lumbar cancer according to each primary cancer type was evaluated. RESULTS: A total of 628 patients were enrolled and categorized according to primary cancer type. The overall median survival rate was 1.11±1.30 years. The three most prevalent primary cancer groups were lung, hepatobiliary, and colorectal cancers, presenting relatively short postoperative survival rates (0.93±1.25, 0.74±0.75 and 0.74±0.88 years, respectively). The best postoperative survival period was observed in breast cancer (2.23±1.83 years), while urinary tract cancer showed the shortest postoperative survival period (0.59±0.69 years). CONCLUSION: The postoperative survival period of patients with lumbar metastatic spinal tumors according to different primary cancers after instrumented fusion was ˃1 year overall, with differences according to different primary origins. This result may provide information regarding the expected postoperative survival after instrumented surgery for lumbar spinal metastases.

Current Concepts in the Treatment of Traumatic C2 Vertebral Fracture : A Literature Review.

The integrity of the high cervical spine, the transition zone from the brainstem to the spinal cord, is crucial for survival and daily life. The region protects the enclosed neurovascular structure and allows a substantial portion of the head motion. Injuries of the high cervical spine are frequent, and the fractures of the C2 vertebra account for approximately 17-25% of acute cervical fractures. We review the two major types of C2 vertebral fractures, odontoid fracture and Hangman's fracture. For both types of fractures, favorable outcomes could be obtained if the delicately selected conservative treatment is performed. In odontoid fractures, as the most common fracture on the C2 vertebrae, anterior screw fixation is considered first for type II fractures, and C1-2 fusion is suggested when nonunion is a concern or occurs. Hangman's fractures are the second most common fracture. Many stable extension type I and II fractures can be treated with external immobilization, whereas the predominant flexion type IIA and III fractures require surgical stabilization. No result proves that either anterior or posterior surgery is superior, and the surgeon should decide on the surgical method after careful consideration according to each clinical situation. This review will briefly describe the basic principles and current treatment concepts of C2 fractures.

Radiological evaluation of atlantoaxial fusion using C2 translaminar screws and C2 pedicle screws: Does the screw halo sign imply fusion failure?

The purpose of this study was to identify the criteria for atlantoaxial (AA) fusion by comparing follow-up lateral radiographs and computed tomography (CT) images. We retrospectively analyzed data from 161 consecutive patients undergoing AA fusion. Patients with a minimum of 1 year of CT follow-up after AA fusion surgery using C2 pedicle screws or translaminar screws (C2TLS) were included. Patients were followed up radiographically at 3, 6, and 12 months after surgery, and dynamic lateral radiographs were also evaluated. A total of 49 patients were analyzed, with a mean CT image follow-up of 41.6 ±â€…37.6 months. Thirty eight patients had C2 pedicle screw placement, and 11 patients underwent planned C2TLS. AA fusion with bridging bone mass formation was achieved in 45/49 (91.8%) patients. Screw halos were observed in 14/49 (28.6%) patients. Among them, final fusion failure occurred in 2 (14.3%) patients. The last follow-up CT showed no difference in the fusion failure rate according to the presence or absence of a screw halo (no halo, 5.7%; halo, 14.3%; P = .33). The differences in C1-2 segmental angles (SA) in flexion-extension dynamic lateral radiographs were 1.99 ±â€…1.62° in the fusion group and 4.37 ±â€…2.13° in the non-fusion group (P = .01). The likelihood of fusion failure increased when the SA gap was greater than 2.62° (P = .05). C2TLS placement had a significantly higher incidence of screw halos. However, the halo sign was not significantly related to final bone fusion. Bone fusion could be predicted when the SA gap of C1-2 was less than 2.62° on the dynamic radiograph.

Ligamentum flavum hypertrophy significantly contributes to the severity of neurogenic intermittent claudication in patients with lumbar spinal canal stenosis.

Ligamentum flavum hypertrophy (LFH) is a known contributor to lumbar spinal canal stenosis (LSCS). However, the clinical significance and quantitative role of LFH compared to other components, such as disc bulging and facet hypertrophy, have not yet been examined. We investigated the correlation between the quantitative radiological factors, clinical symptoms, and outcomes in patients with LSCS. In total, 163 patients diagnosed with single-level (L4-L5) stenosis were included. The patients were divided into 2 groups according to claudication severity: >100 m for mild (n = 92) and < 100 m for severe (n = 71). The visual analog scale (VAS) was used to quantify back and leg pain, and the Oswestry Disability Index (ODI) and Short form-36 (SF-36) physical component summary (PCS) scores, and Macnab criteria were evaluated as clinical factors 6 months after treatment. We measured the baseline canal cross-sectional area, ligamentum flavum (LF) area, disc herniation area, dural sac area, fat area, and LF thickness using MRI. A comparative analysis was performed to evaluate the association between radiologic and clinical factors. Additionally, further comparative analyses between the types of surgeries were performed. Among various radiologic factors, the baseline LF thickness (odds ratio [OR] 1.73; 95% confidence interval [CI] 1.25-2.41) was the only major contributing factor to the severity of claudication in the multivariate logistic regression analysis. The types of surgery (decompression alone vs fusion) did not significantly differ in terms of their clinical outcomes, including back and leg VAS, ODI, SF-36 PCS, and satisfaction with the MacNab classification. LF thickness is a major factor contributing to claudication severity.

CRISPR-Cas9 Gene Editing Protects from the A53T-SNCA Overexpression-Induced Pathology of Parkinson's Disease In Vivo.

Mutations in specific genes, including synuclein alpha (SNCA) that encodes the α-synuclein protein, are known to be risk factors for sporadic Parkinson's disease (PD), as well as critical factors for familial PD. In particular, A53T-mutated SNCA (A53T-SNCA) is a well-studied familial pathologic mutation in PD. However, techniques for deletion of the mutated SNCA gene in vivo have not been developed. Here, we used the CRISPR-Cas9 system to delete A53T-SNCA in vitro as well as in vivo. Adeno-associated virus carrying SaCas9-KKH with a single-guide RNA targeting A53T-SNCA significantly reduced A53T-SNCA expression levels in vitro. Furthermore, we tested its therapeutic potential in vivo in a viral A53T-SNCA-overexpressing rat model of PD. Gene deletion of A53T-SNCA significantly rescued the overexpression of α-synuclein, reactive microgliosis, dopaminergic neurodegeneration, and parkinsonian motor symptoms. Our findings propose CRISPR-Cas9 system as a potential prevention strategy for A53T-SNCA-specific PD.

Kinematics after cervical laminoplasty: risk factors for cervical kyphotic deformity after laminoplasty.

BACKGROUND CONTEXT: Laminoplasty of the cervical spine is widely used as an effective surgical method to treat compressive myelopathy of the cervical spine; however, there is an adverse effect of kyphosis after surgery. The risk factors or predictors of kyphosis have not been sufficiently evaluated. PURPOSE: To assess the risk factors for kyphosis following laminoplasty. STUDY DESIGN: Retrospective study. PATIENT SAMPLE: Patients diagnosed with cervical spondylotic myelopathy (CSM) or ossification of the posterior longitudinal ligament (OPLL) who underwent laminoplasty between May 2011 and October 2018 were enrolled. OUTCOME MEASURES: Changes in lordosis and range of motion (ROM). METHODS: Radiological imaging data were collected from simple neutral and flexion-extension radiographs at baseline and at 2-year follow-up. The ROM from the neutral position to complete flexion was defined as the flexion capacity, and the ROM from the neutral position to complete extension was defined as the extension capacity. RESULTS: This study included 53 patients (mean age, 59.3 years). Multivariate linear regression analysis revealed that, the smaller the preoperative extension capacity, the greater was the decrease in lordosis (p=.025), while the larger the T1 slope, the greater was the decrease in lordosis following laminoplasty (p= .008). Correlation analysis revealed that C2-7 lordosis increased with increasing baseline T1 slope before surgery (p< .01). In patients with large preoperative C2-7 lordosis, the postoperative decrease in ROM tended to be greater (p= .028). However, the degree of lordosis and ROM reduction did not demonstrate a clear correlation with the clinical outcomes at 2 years after surgery. CONCLUSIONS: Kyphotic changes in the cervical spine following laminoplasty were related to preoperative radiological parameters. The greater the preoperative extension capacity, the lower was the decrease in lordosis, and the greater the T1 slope, the greater was the decrease in lordosis.

Label-Free Quantitative Proteome Profiling of Cerebrospinal Fluid from a Rat Stroke Model with Stem Cell Therapy.

Human adipose-derived mesenchymal stem cells (hAMSCs) are capable of immunomodulation and regeneration after neural injury. For these reasons, hAMSCs have been investigated as a promising stem cell candidate for stroke treatment. However, noninvasive experiments studying the effects of grafted stem cells in the host brain have not yet been reported. Cerebrospinal fluid (CSF), which can be collected without sacrificing the subject, is involved in physiological control of the brain and reflects the pathophysiology of various neurological disorders of the central nervous system (CNS). Following stem cell transplantation in a stroke model, quantitative analysis of CSF proteome changes can potentially reveal the therapeutic effect of stem cells on the host CNS. We examined hAMSC-secreted proteins obtained from serum-free culture medium by liquid chromatography-tandem mass spectrometry (LC-MS/MS), which identified several extracellular matrix proteins, supporting the well-known active paracrine function of hAMSCs. Subsequently, we performed label-free quantitative proteomic analysis on CSF samples from rat stroke models intravenously injected with hAMSC (experimental) or phosphate buffered saline (control). In total, 524 proteins were identified; among them, 125 and 91 proteins were increased and decreased with hAMSC treatment, respectively. Furthermore, gene set enrichment analysis revealed three proteins, 14-3-3 theta, MAG, and neurocan, that showed significant increases in the hAMSC-treated model; these proteins are core members of neurotrophin signaling, nerve growth factor (NGF) signaling, and glycosaminoglycan metabolism, respectively. Subsequent histological and neurologic function experiments validated proliferative neurogenesis in the hAMSC-treated stroke model. We conclude that (i) intravenous injection of hAMSCs can induce neurologic recovery in a rat stroke model and (ii) CSF may reflect the therapeutic effect of hAMSCs. Additionally, proteins as 14-3-3 theta, MAG, and neurocan could be considered as potential CSF biomarkers of neuroregeneration. These CSF proteome profiling results would be utilized as valuable resource in further stroke studies.

Extraocular Pressure Measurements to Avoid Orbital Compartment Syndrome in Aneurysm Surgery.

BACKGROUND: Orbital compartment syndrome (OCS) is a rare but devastating complication following pterional craniotomy. Although the causes of OCS are unclear, external compression of the orbit by a myocutaneous flap is commonly mentioned as a major factor. We evaluated the ocular influence of external compression using an extraocular pressure monitor. METHODS: We measured extraocular pressure in 86 patients who underwent surgery for cerebral aneurysm via a pterional approach. Clinical information and radiologic parameters, including the area of the medial rectus muscle (MRM) and the craniotomy height from the bottom of the anterior skull base, were collected. As a control group, 117 patients who underwent surgery without pressure monitoring were also evaluated. RESULTS: Extraocular pressure reached a maximum during craniotomy (mean, 22.0 mm Hg; range, 18.4-51.0 mm Hg) and decreased after myocutaneous flap adjustment (mean, 7.9 mm Hg; range, 5.4-17.5 mm Hg). Pressure before myocutaneous flap manipulation differed between patients with anterior communicating artery (Acomm) aneurysms and other patients (mean, 16.5 mm Hg vs. 9.4 mm Hg; P = 0.003). Among Acomm aneurysm cases, the monitored group showed a significantly lower MRM swelling ratio (postoperative MRM area/preoperative MRM area) compared with the control group (1.03 ± 0.10 vs. 1.17 ± 0.15; P = 0.036). CONCLUSIONS: Myocutaneous flaps can produce unnoticed overpressure on the orbit, resulting in OCS-related blindness during aneurysm clipping surgery, especially in cases involving mandatory lower craniotomy. The continuous extraocular compressive pressure monitoring technique is a simple and effective approach to prevent such a serious complication.

Surgery versus Nerve Blocks for Lumbar Disc Herniation : Quantitative Analysis of Radiological Factors as a Predictor for Successful Outcomes.

OBJECTIVE: To assess the clinical and radiological factors as predictors for successful outcomes in lumbar disc herniation (LDH) treatment. METHODS: Two groups of patients with single level LDH (L4-5) requiring treatment were retrospectively studied. The surgery group (SG) included 34 patients, and 30 patients who initially refused the surgery were included in the nerve blocks group (NG). A visual analogue scale (VAS) for leg and back pain and motor deficit were initially evaluated before procedures, and repeated at 1, 6, and 12 months. Radiological factors including the disc herniation length, disc herniation area, canal length-occupying ratio, and canal area-occupying ratio were measured and compared. Predicting factors of successful outcomes were determined with multivariate logistic regression analysis after the optimal cut off values were established with a receiver operating characteristic curve. RESULTS: There was no significant demographic difference between two groups. A multivariate logistic regression analysis with radiological and clinical (12 months follow-up) data revealed that the high disc herniation length with cutoff value 6.31 mm [odds ratio (OR) 2.35; confidence interval (CI) 1.21-3.98] was a predictor of successful outcomes of leg pain relief in the SG. The low disc herniation length with cutoff value 6.23 mm (OR 0.05; CI 0.003-0.89) and high baseline VAS leg (OR 12.63; CI 1.64-97.45) were identified as predictors of successful outcomes of leg pain relief in the NG. CONCLUSION: The patients with the disc herniation length larger than 6.31 mm showed successful outcomes with surgery whereas the patients with the disc herniation length less than 6.23 mm showed successful outcomes with nerve block. These results could be considered as a radiological criteria in choosing optimal treatment options for LDH.

Intrathecal transplantation of autologous adipose-derived mesenchymal stem cells for treating spinal cord injury: A human trial.

CONTEXT: Spinal cord injury (SCI) can cause irreversible damage to neural tissues. However, there is currently no effective treatment for SCI. The therapeutic potential of adipose-derived mesenchymal stem cells (ADMSCs) has been emerged. OBJECTIVE: We evaluated the effects and safety of the intrathecal transplantation of autologous ADMSCs in patients with SCI. Participants/Interventions: Fourteen patients with SCI were enrolled (12 for ASIA A, 1 for B, and 1 for D; duration of impairments 3-28 months). Six patients were injured at cervical, 1 at cervico-thoracic, 6 at thoracic, and 1 at lumbar level. Autologous ADMSCs were isolated from lipoaspirates of patients' subcutaneous fat tissue and 9 × 107 ADMSCs per patient were administered intrathecally through lumbar tapping. MRI, hematological parameters, electrophysiology studies, and ASIA motor/sensory scores were assessed before and after transplantation. RESULTS: ASIA motor scores were improved in 5 patients at 8 months follow-up (1-2 grades at some myotomes). Voluntary anal contraction improvement was seen in 2 patients. ASIA sensory score recovery was seen in 10, although degeneration was seen in 1. In somatosensory evoked potential test, one patient showed median nerve improvement. There was no interval change of MRI between baseline and 8 months post-transplantation. Four adverse events were observed in three patients: urinary tract infection, headache, nausea, and vomiting. CONCLUSIONS: Over the 8 months of follow-up, intrathecal transplantation of autologous ADMSCs for SCI was free of serious adverse events, and several patients showed mild improvements in neurological function. Patient selection, dosage, and delivery method of ADMSCs should be investigated further.

Expression of matrix metalloproteinase-2 and -9 in human ligamentum flavum cells treated with tumor necrosis factor-α and interleukin-1ß.

OBJECT: An in vitro study was performed to understand the potential roles of matrix metalloproteinase (MMP)-2 and MMP-9 in the elastin degradation of human ligamentum flavum (LF) cells via treatment with tumor necrosis factor-α (TNFα) and interleukin-1ß (IL-1ß). Previous studies have identified a decreased elastin to collagen ratio in hypertrophic LF. Among the extracellular matrix remodeling endopeptidases, MMP-2 and MMP-9 are known to have elastolytic activity. The hypothesis that activated LF cells exposed to inflammation would secrete MMP-2 and MMP-9, thereby resulting in elastin degradation, was examined. METHODS: To examine MMP-2 and MMP-9 expression in human LF, cells were isolated and cultured from LF tissues that were obtained during lumbar disc surgery. Isolated LF cells were equally divided into 3 flasks and subcultured. Upon cellular confluency, the LF cells were treated with TNFα, IL-1ß, or none (as a control) and incubated for 48 hours. The conditioned media were collected and assayed for MMP-2 and MMP-9 using gelatin zymography and Western blot analysis. The electrophoresis bands were compared on densitometric scans using ImageJ software. RESULTS: The conditioned media from the isolated human LF cells naturally expressed 72-kD and 92-kD gelatinolytic activities on gelatin zymography. The IL-1ß-treated LF cells presented sustained increases in the proenzyme/zymogen forms of MMP-2 and -9 (proMMP-2 and proMMP-9), and activeMMP-9 expression (p = 0.001, 0.022, and 0.036, respectively); the TNFα-treated LF cells showed the most elevated proMMP9 secretion (p = 0.006), as determined by Western blot analyses. ActiveMMP-2 expression was not observed on zymography or the Western blot analysis. CONCLUSIONS: TNFα and IL-1ß promote proMMP-2 and proMMP-9 secretion. IL-1ß appears to activate proMMP-9 in human LF cells. Based on these findings, selective MMP-9 blockers or antiinflammatory drugs could be potential treatment options for LF hypertrophy.

A Rare Case of Malignant Lymphoma Occurred at Spinal Epidural Space: A Case Report.

The sacral spinal epidural space is an uncommon site for primary malignant lymphomas, presenting with symptoms associated with cauda equina compression. Especially, lumbo-sacral epidural lymphoma has been reported to be very rare. We present a rare case of 29-year-old male with sacral spinal epidural malignant lymphoma. The patient complained of tingling sensation in his buttocks that was radiating to his calf. The neurological examination was normal. Magnetic resonance imaging (MRI) with contrast showed a well-defined extradural mass lesion at the mid L5 to mid S2 level. The lesion was iso- to hypointense on T1 and T2 weighted images and showed homogenous enhancement and a focal enhancement in the L5 vertebral body on post-contrast images. The patient underwent a L5-S2 laminectomy and subtotal excision of the lesion. Intra-operatively, the lesion was extradural and not densely adherent to the dura; the lesion was friable, not firm, fleshy, brownish and hypervascular. The histologic diagnosis was grade 2 non-Hodgkin's follicular lymphoma. Even though the primary spinal epidural non-Hodgkin's lymphoma is a very rare disease, clinicians should take it into consideration in the differential diagnosis of patients with spinal epidural tumor.

Preliminary Experiences of the Combined Midline-Splitting French Door Laminoplasty with Polyether Ether Ketone (PEEK) Plate for Cervical Spondylosis and OPLL.

OBJECTIVE: The purpose of this study was to evaluate the safety and efficacy of cervical midline-splitting French-door laminoplasty with a polyether ether ketone (PEEK) plate. The authors retrospectively analyzed the results of patients with cervical laminoplasty miniplate (MAXPACER®) without bone grafts in multilevel cervical stenosis. METHODS: Fifteen patients (13 males and 2 females, mean age 50.0 years (range 35-72)) with multilevel cervical stenosis (ossification of the posterior longitudinal ligament and cervical spondylotic myelopathy) underwent a combined surgery of midline-splitting French-door laminoplasty with or without mini plate. All 15 patients were followed for at least 12 months (mean follow-up 13.3 months) after surgery, and a retrospective review of the clinical, radiological and surgical data was conducted. RESULTS: The radiographic results showed a significant increase over the postoperative period in anterior-posterior diameter (9.4±2.2 cm to 16.2±1.1 cm), open angles in cervical lamina (46.5±16.0° to 77.2±13.1°), and sectional volume of cervical central canal (100.5±0.7 cm(2) to 146.5±4.9 cm(2)) (p<0.001). The sagittal alignment of the cervical spine was well preserved (31.7±10.0° to 31.2±7.6°, p=0.877) during the follow-up period. The clinical results were successful, and there were no significant intraoperative complications except for screw displacement in two cases. The mini plate constructs did not fail during the 12 month follow-up period, and the decompression was maintained. CONCLUSION: Despite the small cohort and short follow-up duration, the present study demonstrated that combined cervical expansive laminoplasty using the mini plate is an effective treatment for multilevel cervical stenosis.

The Mechanism of Ligamentum Flavum Hypertrophy: Introducing Angiogenesis as a Critical Link That Couples Mechanical Stress and Hypertrophy.

BACKGROUND: Biochemical alterations associated with mechanical stress have been explored as an initiating step in the pathological progression of ligamentum flavum hypertrophy (LFH); however, this mechanism remains poorly understood. Recently, the inflammation induced after mechanical stress and the subsequent response of ligamentum flavum (LF) cells have been implicated in LFH pathology. OBJECTIVE: To investigate the hypothesis that angiogenesis may be a critical link between hypertrophy and a series of stimulating events, including mechanical stress. METHODS: LF from 20 lumbar spinal canal stenosis (LSCS) patients and 16 non-LSCS patients (control group) were collected during surgery. Patient demographic and radiographic data were obtained. The levels of angiogenic factors (vascular endothelial growth factor [VEGF], angiopoietin-1, vascular cell adhesion molecule, and basic fibroblast growth factor) in the LF were investigated by using an enzyme-linked immunosorbent assay. Angiogenesis was also quantified by immunohistochemical detection of CD34-positive capillaries. The correlations among clinical factors, including radiographic factors, angiogenic factors, and angiogenesis, were statistically analyzed. RESULTS: The LSCS group was older and exhibited a longer symptom duration, wider segmental motion, and thicker LF than the control group. The LSCS group showed significantly higher tissue concentrations of VEGF (P < .001) that positively correlated with LF thickness (r = 0.557, P < .001) and segmental motion (r = 0.586, P < .001). The LSCS group showed significantly more CD34-positive capillaries than the control group (P = .004). CONCLUSION: The LSCS group showed greater segmental motion, higher VEGF concentrations, and more CD34-positive capillaries than the control group. These data indicate that VEGF-mediated angiogenesis following mechanical stress may be a critical step within the series of pathological events in LFH.

What are MRI findings of Spine Benign Metastasizing Leiomyoma? Case report with literature review.

INTRODUCTION: Benign Metastasizing Leiomyoma (BML) is a rare disease that results from metastasis of uterine leiomyoma to distant sites with benign pathologic features. Spine BML is very rare so the information of its features and pathophysiology is seldom known. MATERIALS AND METHODS: We experienced a case of 42-year-old woman who presented with right buttock and leg pain with paresthesia. She had a surgical history of uterine myomectomy. Magnetic resonance imaging (MRI) of the lumbar spine revealed a well-circumscribed mass lesion in the posterior compartment of the L4 vertebral body, with extension into the ventral epidural space and both foramina. The mass showed hypointensity on T1-, T2-weighted images and strong homogeneous enhancement on gadolinium enhanced T1-weighted images. Tumor removal was conducted, and permanent biopsy revealed the mass as leiomyoma. Nine previous spine BML reports, which are known for all, were reviewed along with our case. We collated the clinical information and MRI findings of spine BML to figure out its common denominators. RESULTS: Premenopausal women, previous history of uterine myoma, myomectomy/hysterectomy, and lung BML seemed to be predisposing clinical factors. For the imaging findings, posterior vertebral body invasion with bony destruction, neural foramen invasion, and canal encroachment were shown as common denominators. Especially in MRI findings, low T1 and T2 signal intensities with strong homogeneous enhancement were their common features. CONCLUSION: We gathered the fragmentary information of the spine BML for the first time, especially the MRI findings. Although spine BML is rare, it surely exists. Accordingly, spine surgeons should be suspicious of spine BML given its typical clinical history and MRI findings.

Delayed hinge fracture after plate-augmented, cervical open-door laminoplasty and its clinical significance.

BACKGROUND CONTEXT: Among the various forms of laminoplasty fixation, plate augmentation provides a semirigid arch reconstruction and is gaining popularity as the result of its safety and effectiveness. However, the effects of this procedure on hinge status and subsequent bony healing remain unclear. PURPOSE: We sought to evaluate the status and time course of bony healing of the hinge gutter and to determine the effect on postoperative clinical course of plate-only, open-door cervical laminoplasty. STUDY DESIGN: This was a retrospective clinical series. PATIENT SAMPLE: A total of 79 adult men and women undergoing cervical laminoplasty in a university hospital setting were studied. OUTCOME MEASURES: Time-dependent changes in hinges observed on computed tomography (CT) were used to measure the radiological outcome. A numerical rating scale of axial neck pain and arm pain was used to evaluate the clinical outcome. METHODS: Patients who underwent plate-only, open-door laminoplasty for cervical myelopathy and had available postoperative CT scans were enrolled in this study. Neck pain intensity before and 1 year after surgery was assessed with questionnaires. CT scans (n=125) obtained after surgery were assessed in terms of bony healing of the hinge. RESULTS: Most of the hinges were initially well-bent. Only 9% were found to be "fractured" or "in danger of fracture" at 1 week. Primary healing without callus formation, which is the next step of bony healing of well-bent hinges, was observed in 62% of cases at month 4. The remaining 38% were classified as "fractured" or in the process of "secondary healing." A similar number of hinges was classified as "secondarily healed" after 1 or 2 years of follow-up. All except one hinge were well united and incorporated at the final follow-up, and the number of hinges classified as "fractured or secondarily healed" related to postoperative axial neck pain with respect to the 1-year visual analog scale for the neck and the Neck Disability Index. CONCLUSIONS: Although plate-only, open-door laminoplasty is a safe and reliable surgery for decompression of multilevel cervical disease, the fixation that it provides on the open side may not be sufficiently stable to allow successful primary healing. Additional attention should be paid to the hinged side to prevent delayed fracture in the early postoperative period and to reduce postoperative axial pain.

Radiological significance of ligamentum flavum hypertrophy in the occurrence of redundant nerve roots of central lumbar spinal stenosis.

OBJECTIVE: There were previous reports of redundant nerve roots (RNRs) focused on their clinical significance and pathogenesis. In this study, we investigated the significant radiologic findings that correlate with RNRs occurrence. These relations would provide an advanced clue for clinical significance and pathogenesis of RNRs. METHODS: Retrospective research was performed with data from 126 patients who underwent surgery for central lumbar spinal stenosis (LSS). Finally, 106 patients with common denominators (inter-observer accuracy : 84%) were included on this study. We divided the patients into two groups by MRI, patients with RNRs and those with no RNRs (NRNRs). Comparative analyses were performed with clinical and radiologic parameters. RESULTS: RNRs were found in 45 patients (42%) with central LSS. There were no statistically significant differences between the two groups in severity of symptoms. On the other hand, we found statistically significant differences in duration of symptom and number of level included (p<0.05). In the maximal stenotic level, ligamentum flavum (LF) thickness, LF cross-sectional area (CSA), dural sac CSA, and segmental angulation are significantly different in RNRs group compared to NRNRs group (p<0.05). CONCLUSION: RNRs patients showed clinically longer duration of symptoms and multiple levels included. We also confirmed that wide segmental angulation and LF hypertrophy play a major role of the development of RNRs in central LSS. Together, our results suggest that wide motion in long period contribute to LF hypertrophy, and it might be the key factor of RNRs formation in central LSS.