We isolated α‐chitin, β‐chitin, and γ‐chitin from natural resources by a chemical method to investigate the crystalline structure of chitin. Its characteristics were identified with Fourier transform infrared (FTIR) and solid‐state cross‐polarization/magic‐angle‐spinning (CP–MAS) 13C NMR spectrophotometers. The average molecular weights of α‐chitin, β‐chitin, and γ‐chitin, calculated with the relative viscosity, were about 701, 612, and 524 kDa, respectively. In the FTIR spectra, α‐chitin, β‐chitin, and γ‐chitin showed a doublet, a singlet, and a semidoublet at the amide I band, respectively. The solid‐state CP–MAS 13C NMR spectra revealed that α‐chitin was sharply resolved around 73 and 75 ppm and that β‐chitin had a singlet around 74 ppm. For γ‐chitin, two signals appeared around 73 and 75 ppm. From the X‐ray diffraction results, α‐chitin was observed to have four crystalline reflections at 9.6, 19.6, 21.1, and 23.7 by the crystalline structure. Also, β‐chitin was observed to have two crystalline reflections at 9.1 and 20.3 by the crystalline structure. γ‐Chitin, having an antiparallel and parallel structure, was similar in its X‐ray diffraction patterns to α‐chitin. The exothermic peaks of α‐chitin, β‐chitin, and γ‐chitin appeared at 330, 230, and 310, respectively. The thermal decomposition activation energies of α‐chitin, β‐chitin, and γ‐chitin, calculated by thermogravimetric analysis, were 60.56, 58.16, and 59.26 kJ mol−1, respectively. With the Arrhenius law, ln β was plotted against the reciprocal of the maximum decomposition temperature as a straight line; there was a large slope for large activation energies and a small slope for small activation energies. α‐Chitin with high activation energies was very temperature‐sensitive; β‐Chitin with low activation energies was relatively temperature‐insensitive. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3423–3432, 2004

Compared with the particulate steroid solutions, dexamethasone sodium phosphate had particles that were significantly smaller than red blood cells, had the least tendency to aggregation, and had the lowest density. These characteristics should significantly reduce the risk of embolic infarcts or prevent them from occurring after intra-arterial injection. Until shown otherwise in clinical studies, interventionalists might consider using dexamethasone or another corticosteroid preparation with similar high solubility and negligible particle size when performing epidural injections.

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Background: Epidural injection is performed for treatment of back and radicular pain in patients with lumbosacral disc herniation (LDH). Steroids are usually administered to effectively remove inflammatory mediators, and local anesthetics or saline also contribute to pain reduction by washing out chemical mediators or blocking the nociceptor activity. Controversy exists regarding whether steroids produce superior clinical effects compared with local anesthetics or saline. Objectives: This study investigated whether epidural injection of steroids produces better clinical effects than local anesthetics or saline in the treatment of LDH. Study design: A literature search was performed in MEDLINE, EMBASE, Cochrane review, and KoreaMed for studies published from January 1996 until July 2017. From among the studies fulfilling the search criteria, those that compared the clinical efficacy of steroids and control agents, such as local anesthetics or saline, in terms of pain control and functional improvement were included in this study. Exclusion criteria included a previous history of lumbosacral surgery, non-specific low back pain, severe spinal stenosis, and severe disc degeneration. Setting: A systematic review and meta-analysis using a random effects model on randomized controlled studies (RCTs). Methods: After reviewing titles, abstracts, and full texts of 6,711 studies that were chosen following removal of duplicates after the initial database search, 15 randomized controlled studies were included in our qualitative synthesis. Data including pain score, functional score, and follow-up period were extracted from 14 studies and analyzed using a random effects model to calculate the effect size and its corresponding statistical significance. Quality and level of evidence were established in accordance with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. Results: Steroids and local anesthetics were shown to be effective. Steroid showed significantly better pain control than control agents at 1 month, 3 months, and 6 months. The superiority of steroid in pain control was more prominent at one month, but diminished from 3 months to 1 year, showing no significant superiority in terms of mean difference, With respect to functional score, no significant difference was observed between steroids and control agents. The subgroup analysis showed that steroid revealed significant superiority in pain and functional score at 1 month to saline rather than local anesthetics. Generally, the quality of included studies was evaluated as high-grade, but the evidence level was determined to be moderate, due to inconsistencies. Limitation: Analyses of safety or adverse effects could not be performed due to a lack of available data from the included studies. Conclusions: Steroid is recommended over local anesthetics or saline for pain control in Systematic Review Comparison of Clinical Efficacy of Epidural Injection With or Without Steroid in Lumbosacral Disc Herniation: A Systematic Review and Meta-analysis From: 1 Department of Physical and Rehabilitation Medicine, Spine Health Wooridul Hospital, Seoul, South Korea; 2 Department of Physical and Rehabilitation Medicine, Kyung Hee University, Hospital, Seoul, South Korea; 3 Department of Physical and Rehabilitation Medicine,Dongsan Medical Center, School of Medicine, Keimyung University, Daegu, South Korea; 4 Heal & Teun Rehabilitation & Pain Clinic, Bundang, South Korea; 5 Seocho SeBarun Hospital , Department of Physical and Rehabilitation Medicine, Seoul, South Korea; 6 Chungbuk National University Hospital,, Department of Physical and Rehabilitation Medicine, Cheongjoo, South Korea; 7 Department of Physical and Rehabilitation Medicine, Pusan National University Yangsan Hospital, School of Medicine, Pusan National University, Yangsan, South Korea; 8 Department of Physical and Rehabilitation Medicine, Veterans Medical Center, Seoul, South Korea Address Correspondence: Jung Hwan Lee, MD, PhD Department of Physical and Rehabilitation Medicine Spine Health Wooridul Hospital 445, Hakdong-ro, Gangnam-gu, Seoul, South Korea E-mail: j986802@hanmail.net Disclaimer: There was no external funding in the preparation of this manuscript. Conflict of interest: Each author certifies that he or she, or a member of his or her immediate family, has no commercial association (i.e., consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of Jung Hwan Lee, MD, PhD1 , Dong Hwan Kim, MD, PhD2 , Du Hwan Kim, MD, PhD3 , Kyoung-ho Shin, MD4 , Sung Jin Park, MD5 , Goo Joo Lee, MD6 , Chang-Hyung Lee, MD, PhD7 , and Hee Seung Yang, MD8 www.painphysicianjournal.com Pain Physician 2018; 21:449-467 • ISSN 1533-3159 patients with LDH, with a weak strength of recommendation. The superiority of steroids was remarkable, especially at relatively short-term follow-ups, and maintained until the 1 year followup. The clinical benefits of steroids at 1 month were more prominent when compared with saline, than when compared with local anesthetics. Key words: Steroid, local anesthetics, saline, epidural injection, pain, function, meta-analysis, systemic review