Adiponectin, a hormone secreted by adipocytes, has anti-inflammatory effects and is involved in various physiological and pathological processes such as obesity, inflammatory diseases, and cartilage diseases. However, the function of adiponectin in intervertebral disc (IVD) degeneration is not well understood. This study aimed to elucidate the effects of AdipoRon, an agonist of adiponectin receptor, on human IVD nucleus pulposus (NP) cells, using a three-dimensional in vitro culturing system. This study also aimed to elucidate the effects of AdipoRon on rat tail IVD tissues using an in vivo puncture-induced IVD degeneration model. Analysis using quantitative polymerase chain reaction demonstrated the downregulation of gene expression of proinflammatory and catabolic factors by interleukin (IL)-1β (10 ng/mL) in human IVD NP cells treated with AdipoRon (2 μM). Furthermore, western blotting showed AdipoRon-induced suppression of p65 phosphorylation (p < 0.01) under IL-1β stimulation in the adenosine monophosphate-activated protein kinase (AMPK) pathway. Intradiscal administration of AdipoRon was effective in alleviating the radiologic height loss induced by annular puncture of rat tail IVD, histomorphological degeneration, production of extracellular matrix catabolic factors, and expression of proinflammatory cytokines. Therefore, AdipoRon could be a new therapeutic candidate for alleviating the early stage of IVD degeneration.

Introduction: Osteopetrosis is a skeletal disorder characterized by increased osteodensity and a remodeling defect. The fragility of dense sclerotic bones may lead to an increased incidence of fractures. Although internal fixation can be performed, technical challenges may be experienced because of the increased bone density. Complications such as delayed union, nonunion, or implant failure may occur postoperatively. Presentation of case: We describe a patient with autosomal-dominant osteopetrosis type 2 who suffered a shaft fracture below a plate of his right femur. We performed osteosynthesis with a single locking plate. Union was delayed, and plate breakage occurred along with nonunion of the fracture. The nonunion was addressed using double locking plates, which secured fixation and allowed complete fracture healing. Discussion: There were three reasons of nonunion in our case. First, we left gaps between the fragments. Second, we used mainly cerclage wires, rather than screws, for plate fixation, which led to inadequate stability. Third, the patient was large (height 167 cm, weight 93.1 kg), so the single plate provided insufficient fixing force. We then used double locking plates and attained stronger internal fixation with complete fracture healing. Conclusion: Double plating with locking plates may be an effective treatment option for femoral fractures in patients with osteopetrosis. Highlights:

Growth differentiation factors (GDFs) regulate homeostasis by amplifying extracellular matrix anabolism and inhibiting pro-inflammatory cytokine production in the intervertebral disc (IVD). The aim of this study was to elucidate the effects of GDF-6 on human IVD nucleus pulposus (NP) cells using a three-dimensional culturing system in vitro and on rat tail IVD tissues using a puncture model in vivo. In vitro, Western blotting showed decreased GDF-6 expression with age and degeneration severity in surgically collected human IVD tissues (n = 12). Then, in moderately degenerated human IVD NP cells treated with GDF-6 (100 ng/mL), immunofluorescence demonstrated an increased expression of matrix components including aggrecan and type II collagen. Quantitative polymerase chain reaction analysis also presented GDF-6-induced downregulation of pro-inflammatory tumor necrosis factor (TNF)-α (p = 0.014) and interleukin (IL)-6 (p = 0.016) gene expression stimulated by IL-1β (10 ng/mL). Furthermore, in the mitogen-activated protein kinase pathway, Western blotting displayed GDF-6-induced suppression of p38 phosphorylation (p = 0.041) under IL-1β stimulation. In vivo, intradiscal co-administration of GDF-6 and atelocollagen was effective in alleviating rat tail IVD annular puncture-induced radiologic height loss (p = 0.005), histomorphological degeneration (p < 0.001), matrix metabolism (aggrecan, p < 0.001; type II collagen, p = 0.001), and pro-inflammatory cytokine production (TNF-α, p < 0.001; IL-6, p < 0.001). Consequently, GDF-6 could be a therapeutic growth factor for degenerative IVD disease.

The effect of spine surgery for symptomatic spinal metastases (SSM) on patient prognosis remains unclear. This study aimed to reveal the prognosis of patients with SSM after spine surgery. One hundred twenty-two patients with SSM were enrolled in this prospective cohort study. The patients who received chemotherapy after enrollment were excluded. The decision of surgery depended on patient’s willingness; the final cohort comprised 31 and 24 patients in the surgery and non-surgery groups, respectively. The patients were evaluated by their performance status (PS), activities of daily living (ADL) and ambulatory status. Survival was evaluated by the Kaplan–Meier method. The PS, ADL and ambulation were significantly improved in the surgery group compared to non-surgery group. The median survival was significantly longer in the surgery group (5.17 months, 95% confidence interval (CI) 3.27 to 7.07) than in the non-surgery group (2.23 months, 95% CI 2.03 to 2.43; p = 0.003). Furthermore, the patients with a better PS, ADL and ambulatory status had a significantly longer survival. Surgery improved the PS, ADL, ambulation and survival of patients with SSM. In the management of SSM, spine surgery is not only palliative but may also prolong survival.

Background: Symptomatic spinal metastasis (SSM) decreases the activities of daily living (ADL) and quality of life of cancer patients. However, the risk factors for SSM onset remain unclear. This prospective cohort study aimed to statistically analyze the significant risk factors. Methods: From 2016 to 2018, 210 consecutive patients with spinal metastases were prospectively registered. Patients with SSM at the first consultation and those who were unable to be followed-up owing to poor general condition were excluded. The demographic factors (age, sex, primary cancer, performance status, and ADL), clinical factors (radiation therapy, chemotherapy, molecularly targeted drugs, and bone-modifying agents (BMAs)), and Spinal Neoplastic Instability Score (SINS) were evaluated. Multivariate analysis was performed to identify the risk factors for SSM onset. Furthermore, the threshold was calculated from the receiver operating characteristic curve using the Youden index. Results: Thirty-nine patients who presented with SSM at the first consultation and 43 patients who were unable to be followed-up owing to poor general condition were excluded. Finally, 128 asymptomatic patients were included. Thirty-seven patients (28.9%) developed SSM during the follow-up period. The total SINS (OR: 1.739; 95% CI: 1.345–2.250) was identified as the most significant factor. The cut-off value of the SINS was 9.5 (sensitivity: 67.6%; specificity: 83.5%). Twenty-five (62.5%) of the forty patients with a SINS ≥ 10 developed SSM within a mean of 5.5 months (95% CI: 1.17–9.83). Furthermore, all patients with a SINS ≥ 13 developed SSM (n = 5) within a mean of 1.37 months (95% CI: 0.0–3.01). Conclusions: This study identified the significant risk factors for SSM onset and the threshold of the SINS. If long-term survival is expected, patients with a SINS ≥ 10 should be considered for intervention to prevent SSM.

Objective: Spine surgeons are often at risk of radiation exposure due to intraoperative fluoroscopy, leading to health concerns such as carcinogenesis. This is due to the increasing use of percutaneous pedicle screw (PPS) in spinal surgeries, resulting from the widespread adoption of minimally invasive spine stabilization. This study aimed to elucidate the effectiveness of smart glasses (SG) in PPS insertion under fluoroscopy.Methods: SG were used as an alternative screen for fluoroscopic images. Operators A (2-year experience in spine surgery) and B (9-year experience) inserted the PPS into the bilateral L1–5 pedicles of the lumbar model bone under fluoroscopic guidance, repeating this procedure twice with and without SG (groups SG and N-SG, respectively). Each vertebral body’s insertion time, radiation dose, and radiation exposure time were measured, and the deviation in screw trajectories was evaluated.Results: The groups SG and N-SG showed no significant difference in insertion time for the overall procedure and each operator. However, group SG had a significantly shorter radiation exposure time than group N-SG for the overall procedure (109.1 ± 43.5 seconds vs. 150.9 ± 38.7 seconds; p = 0.003) and operator A (100.0 ± 29.0 seconds vs. 157.9 ± 42.8 seconds; p = 0.003). The radiation dose was also significantly lower in group SG than in group N-SG for the overall procedure (1.3 ± 0.6 mGy vs. 1.7 ± 0.5 mGy; p = 0.023) and operator A (1.2 ± 0.4 mGy vs. 1.8 ± 0.5 mGy; p = 0.013). The 2 groups showed no significant difference in screw deviation.Conclusion: The application of SG in fluoroscopic imaging for PPS insertion holds potential as a useful method for reducing radiation exposure.