To identify the risk factors for cage retropulsion after lumbar interbody fusion surgery. 667 patients underwent lumbar interbody fusion surgery between November 2011 to December 2014 were retrospectively reviewed by the medical recording system in our institute. 8 patients experiencing cage retropulsion were included and 2 underwent the initial surgery in other hospitals. The clinical outcomes were evaluated by visual analog scores (VAS) and Oswestry Disability Index (ODI). Plain radiographs and three-dimensional computed tomography scans were used to analyze the incidence of cage retropulsion. Data were analyzed by SPSS 19.0. The incidence of cage retropulsion was 0.90%(6 out of 665) in our institution. There were 6 male and 2 female with an average age of 45.63 ± 15.48(range, 21-60). The average follow-up time was 23.88 ± 12.69 months(range, 6-43 months) and average retropulsion onset time was 2.75 months(range,1-6 months). 6 patients experienced cage retropulsion at L5/S1 and 2 at L4/5. 6 used bullet-shaped cages and two had kidney-shaped cages. Average bed rest time after the initial surgery was 5.75 ± 1.67 days. 6 patients had neurological deficits and underwent revision surgery. Average operation time and blood loss for revision surgery were much higher than those of the initial surgery (P < 0.05). All the patients got a good result in VAS and ODI both from initial surgery and revision surgery (P < 0.05). There were multiple risk factors for cage retropulsion after lumbar interbody fusion surgery, including patient factors, radiological characteristics, surgical techniques and postoperative reasons. In case of retropulsion, revision surgery was essential for the patients who presented neurological deficits and conservative treatment was recommended for asymptomatic patients.

Recent findings demonstrate that leptin plays a significant role in chondrocyte and osteoblast differentiation. However, the mechanisms by which leptin acts on cartilage endplate (CEP) cells to give rise to calcification are still unclear. The aim of this study was to evaluate the effects of leptin that induced mineralization of CEP cells in vitro and in vivo. We constructed a rat model of lumbar disc degeneration and determined that leptin was highly expressed in the presence of CEP calcification. Rat CEP cells treated with or without leptin were used for in vitro analysis using RT‐PCR and Western blotting to examine the expression of osteocalcin (OCN) and runt‐related transcription factor 2 (Runx2). Both OCN and Runx2 expression levels were significantly increased in a dose‐ and time‐dependent manner. Leptin activated ERK1/2 and STAT3 phosphorylation in a time‐dependent manner. Inhibition of phosphorylated ERK1/2 using targeted siRNA suppressed leptin‐induced OCN and Runx2 expression and blocked the formation of mineralized nodules in CEP cells. We further demonstrated that exogenous leptin induced matrix mineralization of CEP cells in vivo. We suggest that leptin promotes the osteoblastic differentiation of CEP cells via the MAPK/ERK signal transduction pathway and may be used to investigate the mechanisms of disc degeneration.

Background: C5 palsy is a serious complication after cervical decompression surgery in which the patient shows a deterioration in power of the deltoid or biceps brachii by at least one grade in the manual muscle test without aggravation of lower extremity function. Although there are several hypotheses regarding the etiology of C5 palsy, the pathogenesis and preventive measures remain unidentified and many other controversies remain. Objective: To systematically review the clinical features, risk factors, mechanism, and preventive measures of C5 palsy after posterior cervical decompression surgery. Materials and methods: PubMed was searched to identify eligible studies that contained more than 10 cases and focused on C5 palsy. Microsoft Excel was used to analyze the data. Statistical comparisons were made when appropriate. Results: Out of 718 papers involving C5 palsy, 28 met the inclusion criteria. The average incidence rate was 7.8% (range, 1.4–23.0%). Risk factors for C5 palsy included age, male gender, ossification of the posterior longitudinal ligament, and stenosis of the C4–C5 intervertebral foramen. C5 palsy occurred from immediately to 2 months after surgery, and recovery time ranged from 48 h to 41 months. Hypotheses for the mechanism of C5 palsy included root involvement and spinal cord impairment. Foraminotomy and intraoperative neuromonitoring were the two main methods used to prevent C5 palsy. Conclusion: C5 palsy is a serious complication occurring at the early stage after cervical decompression surgery. Foraminotomy and intraoperative neuromonitoring were the two main methods to prevent C5 palsy. The incidence of C5 palsy is low, but it can place a serious burden on the patients’ quality of life and finances. The risk factors and mechanism of C5 palsy are still controversial. However, under conservative therapy, the prognosis is usually good. Higher quality studies are necessary for drawing more reliable and convincing conclusions about this disease.

// <![CDATA[ $('.header-date').hide();$('#titleAuthors').hide();$('#abstractHeader').hide(); // ]]> Yingchao Han1, *, Guanghui Xu2, *, Jingjie Zhang1, Meijun Yan1, Xinhua Li1, Bin Ma1, Lili Jun1, Shan-Jin Wang1, Jun Tan1 1Department of Spine Surgery, Shanghai East Hospital, Tongji University, School of Medicine, Shanghai, 200120, China 2Department of Orthopedics, Shanghai Zhabei District Central hospital, Zhonghuaxin Road Zhabei District, Shanghai, 200070, China *These authors have contributed equally to this work Correspondence to: Shan-Jin Wang, email: wangspine@yahoo.com Jun Tan, email: dr.tan@139.com Keywords: leptin, osteocalcin, ATDC5, growth plate, chondrocyte Received: April 18, 2016 Accepted: August 11, 2016 Published: August 24, 2016