Long noncoding RNA BCAR4 promotes osteosarcoma progression through activating GLI2-dependent gene transcription.

Despite great advances have been made in the understanding of biology of osteosarcoma, the molecular mechanisms involved in osteosarcoma tumorigenesis and progression are still largely unknown. Long noncoding RNA (lncRNA) is a new type of RNA molecule, which plays pivotal roles in many tumors. lncRNA BCAR4 has been identified as an oncogenetic lncRNA involved in the progression of breast cancer. However, the functions and clinical significances of BCAR4 in osteosarcoma are unknown now. In this study, we found that BCAR4 was significantly upregulated in osteosarcoma tissues. Increased expression of BCAR4 was significantly correlated with large tumor size, advanced Enneking stage, lung metastasis, and poor prognosis. Functional experiments demonstrated that knockdown of BCAR4 inhibits the proliferation and migration of osteosarcoma cell in vitro. Consistently, knockdown of BCAR4 inhibits osteosarcoma tumorigenesis and lung metastasis in vivo. Chromatin isolation by RNA purification assay showed that BCAR4 physically associates with the promoters of GLI2 target genes. The depletion of BCAR4 inhibits the expression of GLI2 target genes and GLI2 reporter luciferase activity in a dose-dependent manner. The expression of BCAR4 and GLI2 target genes is significantly correlated in osteosarcoma tissues. Depletion of DLI2 abolished the effects of BCAR4 on osteosarcoma. Taken together, these findings demonstrated that BCAR4 promotes osteosarcoma progression via activating GLI2-dependent gene transcription and serves as a potential prognostic biomarker and a therapeutic target of osteosarcoma.

Beyond Magnification and Illumination: Ergonomics with a 3D Exoscope in Lumbar Spine Microsurgery to Reduce Musculoskeletal Injuries.

OBJECTIVE: The risk of musculoskeletal injuries (MSIs) increases over years of practice which may lead to career-ending among surgeons. Exoscopes represent a new generation of imaging systems that help surgeons operate in a more comfortable posture. This article aimed to assess advantages and limitations, especially ergonomics with a 3D exoscope in lumbar spine microsurgery versus an operating microscope (OM) to reduce MSIs. METHODS: From March 2018 to May 2020, 90 patients with lumbar disc herniation undergoing a single-level minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) procedure were included. Forty-seven patients were operated with the assistance of the exoscope and 43 patients were operated with the assistance of the OM. Clinical data, magnification, and illumination were evaluated. In particular, the ergonomics of surgeons was evaluated by a questionnaire (subjective) and a rapid entire body assessment (REBA; objective). RESULTS: The postoperative outcomes were reasonably well balanced between the two groups. The handling of the exoscope was comparable to that of the OM. The depth perception, image quality, and illumination of the exoscope were inferior to those of the OM in MIS-TLIF with long and deep approaches. The educational and training function of the exoscope was superior to that of the OM. Importantly, surgeons rated the ergonomics of the exoscope as very high on the questionnaire and the REBA to the OM (P = 0.017). CONCLUSIONS: This study showed that the exoscope was a safe and effective alternative to the OM for assisting the MIS-TLIF procedure with the unique advantage of ergonomics to reduce musculoskeletal injuries.

Cervical and First Thoracic Spine Hounsfield Units Assessment and Relationship to Clinical Outcomes and Cervical Sagittal Parameters in Patients Undergoing Anterior Cervical Spine Surgery.

OBJECTIVE: This study had 3 objectives: to compare bone mineral density (BMD) from 3 axial slices, subchondral trabecular bone 2 mm inferior to the cranial endplate, middle of the vertebral body, and subchondral trabecular bone 2 mm superior to the caudal endplate; assess BMD variations and correlations of C1-T1 vertebrae; and correlate BMD with clinical outcomes and cervical sagittal parameters in patients undergoing anterior cervical discectomy and fusion. METHODS: The study enrolled 71 patients who underwent anterior cervical discectomy and fusion between March 2017 and January 2020. Patient demographics, clinical outcomes, cervical sagittal parameters, and Hounsfield units (HUs) of C1-T1 vertebrae were recorded. Analysis of variance was performed to compare HUs from the axial slices. Pearson correlation coefficient was performed to calculate the relationship between mean HUs of C1-T1 and to assess correlations of mean HUs with clinical outcomes and cervical sagittal parameters. RESULTS: There were no significant differences between HUs of 3 axial levels. Mean HUs were highest in the mid-cervical spine (C4). Significant correlations in mean HUs among all measured spinal levels were observed. Age, sex, and body mass index were not related to mean HUs. Visual analog scale, Neck Disability Index, and Patient Health Questionnaire-9 scores were not related to HUs before and after surgery. There were significant correlations among mean HUs of C2-T1 vertebrae, C2-C7 sagittal vertical axis, and cranial tilt. Mean HUs of C4 had the strongest correlation with C2-C7 sagittal vertical axis. CONCLUSIONS: To our knowledge, this is the first study of cranial and caudal subchondral trabecular BMD using HUs and comparing them with the middle of the vertebral body and study of correlations between mean HUs of C1-T1 vertebrae and clinical outcomes and cervical sagittal parameters. Correcting C2-C7 sagittal vertical axis and cranial tilt would improve BMD of C1-T1 vertebrae.

Cervical Spine Microsurgery with the High-Definition 3D Exoscope: Advantages and Disadvantages.

OBJECTIVE: The aim of this study was to evaluate our experience with a high-definition 3-dimensional (3D) exoscope (EX) for cervical spine surgery versus a binocular operating microscope (OM). METHODS: A retrospective review of patients undergoing a single-level anterior cervical discectomy and fusion (ACDF) procedure for the treatment of cervical myelopathy from March 2019 to May 2020 was performed. Demographic, perioperative, and clinical outcomes of 50 patients were included, 23 of whom received assistance from the 3D exoscope (EX group) and 27 of whom received assistance from the OM (OM group). Operative baseline and postoperative outcome parameters were evaluated. Periprocedural handling, visualization, and illumination by the EX, as well as surgeons' ergonomics, were scored using a questionnaire and rapid upper limb assessment (RULA). RESULTS: Baseline characteristics were similar between the 2 groups. There were no significant differences between groups in mean operative time, blood loss, duration of admission, or postoperative improvement of symptoms. Both groups showed similar clinical improvements after surgery. There were no intraoperative complications in either group. According to the attending surgeons, the intraoperative handling of instruments for the EX was rated to be comparable to that of the OM. Surgeons rated the comfort level of the intraoperative posture for the EX as very high on the subjective questionnaire and equal to the OM on the objective RULA. When compared with the OM, depth perception, image quality, and illumination for the EX were rated as inferior in ACDF procedures with long approaches. The operative education and training function of the EX was rated to be superior to that of the OM. CONCLUSIONS: Overall, our study showed that the EX appears to be a safe alternative for common ACDF with the unique advantage of excellent comfort and also serves a useful educational tool for the surgical team. However, our investigation revealed several important limitations of this system, including slightly inferior visualization and illumination quality compared with the OM.