The Fate of Pre-Existing L5-S1 Degeneration following Oblique Lumbar Interbody Fusion of L4-L5 and Above.

BACKGROUND: Previous studies have identified various risk factors for adjacent segment disease (ASD) at the L5-S1 level after fusion surgery, including preoperative sagittal imbalance, longer fusion, and preoperative disc degeneration. However, only a few studies have explored the risk factors for ASD at the L5-S1 level after oblique lumbar interbody fusion (OLIF) at the L4-L5 level and above. This study aimed to identify the risk factors for symptomatic ASD at the L5-S1 level in patients with pre-existing degeneration after OLIF at L4-L5 and above. METHODS: We retrospectively reviewed the data of patients who underwent OLIF at L4-L5 and above, with a minimum follow-up period of 2 years. Patients with central stenosis or Lee grade 2 or 3 foraminal stenosis at L5-S1 preoperatively were excluded. Patients were divided into ASD and non-ASD groups based on the occurrence of new-onset L5 or S1 radicular pain requiring epidural steroid injection (ESI). The clinical and radiological factors were analyzed. Logistic regression was used to identify the risk factors for ASD of L5-S1. RESULTS: A total of 191 patients with a mean age ± standard deviation of 68.6 ± 8.3 years were included. Thirty-four (21.7%) patients underwent ESI at the L5 root after OLIF. In the logistic regression analyses, severe disc degeneration (OR (95% confidence interval (CI)): 2.65 (1.16-6.09)), the presence of facet effusion (OR (95% CI): 2.55 (1.05-6.23)), and severe paraspinal muscle fatty degeneration (OR (95% CI): 4.47 (1.53-13.05)) were significant risk factors for ASD in L5-S1. CONCLUSIONS: In this study, the presence of facet effusion, severe disc degeneration, and severe paraspinal muscle fatty degeneration at the L5-S1 level were associated with the development of ASD at L5-S1 following OLIF at L4-L5 and above. For patients with these conditions, surgeons could consider including L5-S1 in the fusion when considering OLIF at the L4-L5 level and above.

Efficacy of Total En Bloc Spondylectomy versus Stereotactic Ablative Radiotherapy for Single Spinal Metastasis.

To compare total en bloc spondylectomy (TES) with stereotactic ablative radiotherapy (SABR) for single spinal metastasis, we undertook a single center retrospective study. We identified patients who had undergone TES or SABR for a single spinal metastasis between 2000 and 2019. Medical records and images were reviewed for patient and tumor characteristics, and oncologic outcomes. Patients who received TES were matched to those who received SABR to compare local control and survival. A total of 89 patients were identified, of whom 20 and 69 received TES and SABR, respectively. A total of 38 matched patients were analyzed (19 TES and 19 SABR). The median follow-up period was 54.4 (TES) and 26.1 months (SABR) for matched patients. Two-year progression-free survival (PFS) and overall survival (OS) rates were 66.7% and 72.2% in the TES and 38.9% and 50.7% in the SABR group, respectively. At the final follow-up of the matched cohorts, no significant differences were noted in OS (p = 0.554), PFS (p = 0.345) or local progression (p = 0.133). The rate of major complications was higher in the TES than in the SABR group (21.1% vs. 10.5%, p = 0.660). These findings suggest that SABR leads to fewer complications compared to TES, while TES exhibits better mid-term control of metastatic tumors.

An Updated Review on the Treatment Strategy for Spinal Metastasis from the Spine Surgeon's Perspective.

Spinal metastasis is a common issue causing significant pain and disability in cancer patients. A multidisciplinary approach consisting of chemotherapy, radiotherapy, and surgical treatment is used for treating patients with metastatic spinal tumors. Due to recent advancements in medical and radiation oncology, like tumor genetics and stereotactic radiotherapy, this treatment strategy would change inevitably. Therefore, the decision-making systems developed for assisting physicians and surgeons to choose the most appropriate treatment for each patient with spinal metastasis need to evolve. In this review, the recent developments, validations, and modifications of these systems, as well as suggestions for future systems have been discussed. Recently, separation surgery combined with stereotactic radiotherapy (hybrid therapy) has gained popularity. Additionally, the evidence for hybrid therapy presented in the literature has been reviewed.

Separation surgery followed by stereotactic ablative radiotherapy for metastatic epidural spinal cord compression: A systematic review and meta-analysis for local progression rate.

Introduction: Spinal metastasis is the most common metastatic skeletal disease in cancer patients. Metastatic epidural spinal cord compression (MESCC), which occurs in 5-14% of cancer patients, is an oncological emergency because it may cause a permanent neurological deficit. Separation surgery followed by stereotactic ablative radiotherapy (SABR), so-called "hybrid therapy," has shown effectiveness in local control of spinal metastasis and has become an integral treatment option for patients with MESCC. Therefore, we performed a meta-analysis and meta-regression analysis to clarify the local progression rate of hybrid therapy and the risk factors for local progression. Methods: We searched PubMed, EMBASE, Scopus, Cochrane Library, and Web of Science databases from inception to December 2021. Meta-analyses of proportions were used to analyze the data using a random-effects model to calculate the pooled 1-year local progression rate and confidence interval. Subgroup analyses were performed using meta-analyses of odds ratio (OR) for comparisons between groups. We also conducted a meta-regression analysis to identify the factors that caused heterogeneity. Results: A total of 661 patients from 13 studies (10 retrospective and 3 prospective) were included in the final meta-analysis. The quality of the included studies assessed using the Newcastle - Ottawa scale ranged from poor to fair (range, 4-6). The pooled local progression rate was 10.2 % (95 % confidence interval [CI], 7.8-12.8 %; I2 = 30 %) and 13.7 % (95 % CI, 9.3-18.8 %; I2 = 55 %) at postoperative 1 and 2 years, respectively. The subgroup analysis indicated that patients with a history of prior radiotherapy (OR, 5.14; 95 % CI, 1.71-15.51) and lower radiation dose per fraction (OR, 4.57; 95 % CI, 1.88-11.13) showed significantly higher pooled 1-year local progression rates. In the moderator analysis, the 1-year local progression rate was significantly associated with the proportion of patients with a history of prior radiotherapy (p = 0.036) and those with colorectal cancer as primary origin (p < 0.001). Conclusions: The pooled 1-year local progression rate of hybrid therapy for MESCC was 10.2%. In subgroup and moderator analyses, a lower radiation dose per fraction, history of prior radiotherapy, and colorectal cancer showed a significant association with the 1-year local progression rate.

Lemon Balm and Corn Silk Mixture Alleviates Metabolic Disorders Caused by a High-Fat Diet.

We recently reported that varying combination ratios of lemon balm (Mellissa officinalis L.) and corn silk extracts (Stigma of Zea mays L. fruit) could reduce the obesity caused by a high-fat diet (HFD). The present study investigated the dose-dependent effect of a 1:1 (w:w) mixture of lemon balm and corn silk extracts (M-LB/CS) on HFD-mediated metabolic disorders and compared the effect with metformin. Oral administration of 50-200 mg/kg of M-LB/CS for 84 days significantly inhibited HFD-induced body weight gain, adipocyte hypertrophy, and lipogenic gene induction without affecting food consumption in mice. Biochemical analyses showed that M-LB/CS blocked abnormal lipid accumulation in the blood by escalating fecal lipid excretion. In addition, M-LB/CS prevented HFD-mediated pancreatic atrophy, decreased the number of insulin- and glucagon-immunoreactive cells, and inhibited increases in glycated hemoglobin, glucose, and insulin. Moreover, M-LB/CS also reduced hepatic injury, lipid accumulation, gluconeogenesis, and lipid peroxidation in parallel with the induction of AMP-activated protein kinase and antioxidant enzymes. Furthermore, M-LB/CS protected the kidney by inhibiting tubular vacuolation and reducing serum creatinine and blood urea nitrogen levels. The prophylactic effect of 100 mg/kg M-LB/CS-administration was comparable to that of metformin. Therefore, M-LB/CS may be an alternative option for managing obesity and its related metabolic disorders.

Lemon Balm and Corn Silk Extracts Mitigate High-Fat Diet-Induced Obesity in Mice.

Lemon balm and corn silk are valuable medicinal herbs, which exhibit variety of beneficial effects for human health. The present study explored the anti-obesity effects of a mixture of lemon balm and corn silk extracts (M-LB/CS) by comparison with the effects of single herbal extracts in high-fat diet (HFD)-induced obesity in mice. HFD supplementation for 84 days increased the body weight, the fat mass density, the mean diameter of adipocytes, and the thickness of fat pads. However, oral administration of M-LB/CS significantly alleviated the HFD-mediated weight gain and adipocyte hypertrophy without affecting food consumption. Of the various combination ratios of M-LB/CS tested, the magnitude of the decreases in weight gain and adipocyte hypertrophy by administration of 1:1, 1:2, 2:1, and 4:1 (w/w) M-LB/CS was more potent than that by single herbal extracts alone. In addition, M-LB/CS reduced the HFD-mediated increases in serum cholesterol, triglyceride, and low-density lipoprotein, prevented the reduction in serum high-density lipoprotein, and facilitated fecal excretion of cholesterol and triglyceride. Moreover, M-LB/CS mitigated the abnormal changes in specific mRNAs associated with lipogenesis and lipolysis in the adipose tissue. Furthermore, M-LB/CS reduced lipid peroxidation by inhibiting the HFD-mediated reduction in glutathione, catalase, and superoxide dismutase. Therefore, M-LB/CS is a promising herbal mixture for preventing obesity.

Highly Chlorinated Polyvinyl Chloride as a Novel Precursor for Fibrous Carbon Material.

Pure, highly chlorinated polyvinyl chloride (CPVC), with a 63 wt % of chlorine, showed a unique-thermal-pyrolytic-phenomenon that meant it could be converted to carbon material through solid-phase carbonisation rather than liquid-phase carbonisation. The CPVC began to decompose at 270 °C, with a rapid loss in mass due to dehydrochlorination and novel aromatisation and polycondensation up to 400 °C. In this study, we attempted to prepare carbon fibre (CF) without oxidative stabilisation, using the aforementioned CPVC as a novel precursor. Through the processes of solution spinning and solid-state carbonisation, the spun CPVC fibre was directly converted to CF, with a carbonisation yield of 26.2 wt %. The CPVC-derived CF exhibited a relatively smooth surface; however, it still demonstrated a low mechanical performance. This was because the spun fibre was not stretched during the heat treatment. Tensile strength, Young's modulus and elongation values of 590 ± 84 MPa, 50 ± 8 GPa, and 1.2 ± 0.2%, respectively, were obtained from the CPVC spun fibre, with an average diameter of 19.4 µm, following carbonisation at 1600 °C for 5 min.

Platelet-Rich Plasma Pretreatment on Grit-Blasted Titanium Alloy for Enhanced Osteogenic Differentiation of Human Adipose-Derived Stem Cells.

BACKGROUND: Adequate bone formation around titanium alloy implants is integral to successful implantation surgery. Stem cell-coated implants may accelerate peri-implant bone formation. This study investigates the effect of platelet-rich plasma (PRP) pretreatment on a titanium-alloy surface in terms of proliferation and osteogenic differentiation of human adipose-derived stem cells (hADSCs). METHODS: Allogenic leukocyte-depleted PRP was obtained from blood supernatants. The hADSCs were isolated from thigh subcutaneous fat tissue. Grit-blasted titanium plugs were used in two different groups. In one group, 200 µL of PRP was added to the grit-blasted titanium plugs. The hADSCs were seeded in two groups: grit-blasted titanium plugs with or without PRP. The number of hADSCs was measured after 4 hours, 3 days, and 7 days of culture using Cell Counting Kit-8. Osteogenesis of hADSCs was measured by using an alkaline phosphatase activity assay on days 7 and 14, and a calcium assay on days 14 and 21. Osteogenic gene expression was measured by using reverse transcription polymerase chain reaction analysis of alkaline phosphatase, osteocalcin, and type I collagen mRNA. The microscopic morphology of grit-blasted titanium plugs with or without PRP was examined with a field-emission scanning electron microscope using a JSM-7401F apparatus on days 1 and 7. RESULTS: Proliferation and osteogenic differentiation of hADSCs were found to be significantly higher on the grit-blasted titanium alloy preprocessed with PRP than the same alloy without pretreatment. Furthermore, a structural fibrillar mesh developed compactly on the grit-blasted titanium alloy with the PRP pretreatment. CONCLUSIONS: Our results demonstrate that a hADSC-based approach can be used for tissue-engineered peri-implant bone formation and that PRP pretreatment on the grit-blasted titanium alloy can improve proliferation and osteogenic differentiation of hADSCs.

Frequency and associated factor of atypical periprosthetic femoral fracture after hip arthroplasty.

BACKGROUND: Atypical femoral fracture (AFF) is a serious complication after the use of bisphosphonates, and periprosthetic femoral fracture (PFF) appeared as a common complication after hip arthroplasty, especially in senile patients. Although American Society for Bone and Mineral Research has excluded PFFs from the definition of AFFs, several case reports found PFF patients undergoing bisphosphonate treatment, have fractures resembling AFF and the authors suggested that AFF can also occur in operated femurs after hip arthroplasty. To date, the frequency and risk factors of atypical PFF are unknown. The purpose of our study was (1) to evaluate the proportion of atypical PFF among Vancouver type B PFFs, and (2) to determine the association between occurrence of atypical PFF and use of bisphosphonate. METHODS: We reviewed medical records and radiographs of 67 Vancouver type B PFFs (67 patients) due to low-energy trauma and classified them into atypical PFF group and ordinary PFF group. We calculated the proportion of atypical PFFs among PFFs and identified risk factors for atypical PFF. RESULTS: Among the 67 PFFs, 7 fractures (10.4%) were classified as atypical PFF. Longer duration of bisphosphonate use was an independent risk factor of atypical PFF. (Odds ratio 2.600, 95% CI 1.184-5.709, p = 0.017). CONCLUSION: In accordance with wide use of bisphosphonate, atypical PFFs after hip arthroplasty are not rare anymore. Physicians should suspect the atypical PFF, when they meet low-energy fracture in bisphosphonate users, and radiographs show features of AFF.

Pore structure analysis of activated carbon fiber by microdomain-based model.

The pore structures of commercial pitch and PAN-based activated carbon fibers (ACFs) were investigated. The pore size and pore size distribution of pitch-based ACFs were measured by nitrogen adsorption isotherms and 129Xe NMR spectroscopy and compared with each other. Scanning tunneling microscopy showed that the ACFs were composed of spherical microdomain units the size of a few nanometers. The activation mechanism of ACFs was considered and explained by novel hypothesis; the concept of microdomain structure of ACFs was considered and explained to overcome limitation of the conventional fractal hypothesis. Whereas micropores were generated on each microdomain, the origin of mesopores was interdomain pores, resulting from the microdomain hypothesis.

Electrochemical capacitances of well-defined carbon surfaces.

Reported is the capacitive behavior of homogeneous and well-defined surfaces of pristine carbon nanofibers (CNFs) and surface-modified CNFs. The capacitances of the well-defined CNFs were measured with cyclic voltammetry to correlate the surface structure with capacitance. Among the studied pristine CNFs, the edge surfaces of platelet CNFs (PCNF) and herringbone CNFs were more effective in capacitive charging than the basal plane surface of tubular CNF by a factor of 3-5. Graphitization of PCNF (GPCNF) changed the edge surface of PCNF into a domelike basal plane surface, and the corresponding capacitances decreased from 12.5 to 3.2 F/g. A chemical oxidation of the GPCNF, however, recovered a clear edge surface by removal of the curved basal planes to increase the capacitance to 5.6 F/g. The difference in the contribution of the edge surface and basal-plane surface to the capacitance of CNF was discussed in terms of the anisotropic conductivity of graphitic materials.