Fengning Li

A Novel High Mechanical Property PLGA Composite Matrix Loaded with Nanodiamond-Phospholipid Compound for Bone Tissue Engineering.

A potential bone tissue engineering material was produced from a biodegradable polymer, poly(lactic-co-glycolic acid) (PLGA), loaded with nanodiamond phospholipid compound (NDPC) via physical mixing. On the basis of hydrophobic effects and physical absorption, we modified the original hydrophilic surface of the nanodiamond (NDs) with phospholipids to be amphipathic, forming a typical core-shell structure. The ND-phospholipid weight ratio was optimized to generate sample NDPC50 (i.e., ND-phospholipid weight ratio of 100:50), and NDPC50 was able to be dispersed in a PLGA matrix at up to 20 wt %. Compared to a pure PLGA matrix, the introduction of 10 wt % of NDPC (i.e., sample NDPC50-PF10) resulted in a significant improvement in the materials mechanical and surface properties, including a decrease in the water contact angle from 80 to 55°, an approximately 100% increase in the Youngs modulus, and an approximate 550% increase in hardness, thus closely resembling that of human cortical bone. As a novel matrix supporting human osteoblast (hFOB1.19) growth, NDPC50-PFs with different amounts of NDPC50 demonstrated no negative effects on cell proliferation and osteogenic differentiation. Furthermore, we focused on the behaviors of NDPC-PFs implanted into mice for 8 weeks and found that NDPC-PFs induced acceptable immune response and can reduce the rapid biodegradation of PLGA matrix. Our results represent the first in vivo research on ND (or NDPC) as nanofillers in a polymer matrix for bone tissue engineering. The high mechanical properties, good in vitro and in vivo biocompatibility, and increased mineralization capability suggest that biodegradable PLGA composite matrices loaded with NDPC may potentially be useful for a variety of biomedical applications, especially bone tissue engineering.

A meta-analysis showing that high signal intensity on T2-weighted MRI is associated with poor prognosis for patients with cervical spondylotic myelopathy

We used PubMed, Medline, and EMBASE to conduct a meta-analysis to determine the significance of high signal intensity on T2-weighted MRI for predicting postoperative prognosis in patients with cervical spondylotic myelopathy (CSM). Although patients with CSM with high signal intensity on T2-weighted MRI usually had a poor prognosis even after undergoing surgery, some researchers have argued recently that high-intensity signals are not associated with postoperative prognosis. Data consistent with the inclusion criteria of this study were cited for meta-analysis using Review Manager 5 Software. The postoperative recovery ratio specified by the Japanese Orthopedic Association (JOA) was assessed using the weighted mean difference (WMD) method. Five articles (one prospective; four retrospective) involving 309 patients with CSM were included. The aggregate WMD with regard to the postoperative JOA recovery ratio between the T2-weighted high signal intensity positive (+) group and the T2-weighted high signal intensity negative (-) group was -6.56, and the 95% confidence interval (CI) was -12.15 to -0.97 (p=0.02). Thus, we concluded that in patients with CSM, the postoperative JOA recovery ratio in the T2-weighted (+) group was lower than that in the T2-weighted (-) group.

Anterior Fusion Technique for Multilevel Cervical Spondylotic Myelopathy: A Retrospective Analysis of Surgical Outcome of Patients with Different Number of Levels Fused

Objective The anterior approach for multilevel CSM has been developed and obtained favorable outcomes. However, the operation difficulty, invasiveness and operative risks increase when multi-level involved. This study was to assess surgical parameters, complications, clinical and radiological outcomes in the treatment of 2-, 3- and 4-level CSM. Methods A total of 248 patients with 2-, 3- or 4-level CSM who underwent anterior decompression and fusion procedures between October 2005 and June 2011 were divided into three groups, the 2-level group (106 patients), the 3-level group (98 patients) and the 4-level group (44 patients). The clinical and Radiographic outcomes including Japanese Orthopedic Association (JOA) score, Neck Disability Index (NDI) score, Odoms Scale, hospital stay, blood loss, operation time, fusion rate, cervical lordosis, cervical range of motion (ROM), and complications were compared. Results At a minimum of 2-year follow-up, no statistical differences in JOA score, NDI score, Odoms Scale, hospital stay, fusion rate and cervical lordosis were found among the 3 groups. However, the mean postoperative NDI score of the 4-level group was significantly higher than that in the other two groups (P<0.05), and in terms of postoperative total ROM, the 3-level group was superior to the 4-level group and inferior to 2-level group (P<0.05). The decrease rate of ROM in the 3-level group was significantly higher than that in the 2-level group, and lower than that in the 4-level group (P<0.05). Conclusions As the number of involved levels increased, surgical results become worse in terms of operative time, blood loss, NDI score, cervical ROM and complication rates postoperatively. An appropriate surgical procedure for multilevel CSM should be chosen according to comprehensive clinical evaluation before operation, thus reducing fusion and decompression levels if possible.

Effectiveness of tranexamic acid in reducing blood loss in spinal surgery: a meta-analysis

BackgroundThe aim of present meta-analysis was to evaluate the effectiveness of tranexamic acid (TXA) use in reducing blood loss and the related thrombotic complications in spinal surgery.MethodsThree databases (MEDLINE, EMBASE, and the Cochrane Library) were searched through October 2012 to identify the relevant randomized controlled trials (RCTs) regarding the TXA effective in spinal surgery. Mean differences (MDs) of blood loss, blood transfusions, and postoperative partial thromboplastic time (PTT), odds ratios (ORs) of blood transfusion and thrombotic complication in TXA-treated group compared to placebo group were extracted and combined using random-effect meta-analysis.ResultsA total of 6 RCTs comprising 411 patients were included in the meta-analysis according to the pre-defined selection criteria. TXA-treated group had significantly less amount of blood loss and blood transfusions per patient, and had smaller proportion of patients who required a blood transfusion compared with the placebo group. The use of TXA can significantly reduce the postoperative PTT with weighted MD of -1.59 [(95% confidence interval (CI):-3.07, -0.10] There is a null association between thrombosis complications and the use of TXA.ConclusionWe conclude that the use of TXA in patients undergoing spinal surgery appears to be effective in reducing the amount of blood loss, the volume of blood transfusion, the transfusion rate, and the postoperative PTT. However, data were too limited for any conclusions regarding safety. More high-quality RCTs are required before recommending the administered of TXA in spinal surgery.

Tracheal Traction Exercise Reduces the Occurrence of Postoperative Dysphagia After Anterior Cervical Spine Surgery

Study Design. We designed a novel anterior cervical spine surgery preoperative treatment comprising mechanical trachea/esophagus traction and compared the postoperative outcome regarding dysphagia with nontreated patients. Objective. We investigated whether the newly developed preoperative tracheal/esophageal traction exercise (TTE) treatment has an effect on postoperative dysphagia after anterior cervical spine surgery. Summary of Background Data. Dysphagia is a postoperative complication that occurs after anterior cervical spine surgery, and known treatments are perioperative application of methylprednisolone, monitoring of endotracheal tube cuff pressure, and the use of low-profile plates. Methods. We compared the neck disability index, visual analogue scale scores for arm and neck pain, and Bazaz dysphagia scores, a dysphagia index, of 2 randomized groups, 1 week, 3 weeks, 6 weeks, 3 months, and 6 months after cervical spine surgery. One group received TTE treatment for 3 consecutive days before surgery, whereas the control group did not. Results. In the first week after operation, the Bazaz dysphagia scores for patients with second- to fourth-level fusions in the TTE group were significantly better than that in the control group (P = 0.000 for second- and third-level fusions and P = 0.013 for fourth-level fusion). Also at 3 weeks after surgery, the second- to fourth-level fusion patients in the TTE group had better Bazaz scores than those in the control group (P = 0.000 for second- and third-level fusions and P = 0.004 for fourth-level fusion). There was no significant difference of neck disability index and visual analogue scale scores between the 2 groups. Conclusion. Dysphagia could be reduced in patients with multiple-level fusion after anterior cervical spine surgery by preoperative TTE treatment.

Enhanced p62 expression triggers concomitant autophagy and apoptosis in a rat chronic spinal cord compression model.

Chronic spinal cord compression is the result of mechanical pressure on the spinal cord, which in contrast to traumatic spinal cord injury, leads to slowly progressing nerve degeneration. These two types of spinal cord injuries may trigger similar mechanisms, including motoric nerve cell apoptosis and autophagy, however, depending on differences in the underlying injury severity, nerve reactions may predominantly involve the conservation of function or the initiation of functions for the removal of irreversibly damaged cells. p62 is a multidomain adapter protein, which is involved in apoptosis and cell survival as well as autophagy, and is a common component of protein aggregations in neurodegenerative diseases. In the present study, a rat chronic spinal cord compression model was used, in which the spinal cord was progressively compressed for six weeks and then constantly compressed for another 10 weeks. As a result Basso, Beattie and Bresnahan locomotor scaling revealed a gradual score decrease until the 6th week followed by constant recovery until the 16th week after spinal cord compression was initiated. During the first eight weeks of the experiment, p62 and nuclear factor-κB (NF-κB) were increasingly expressed up to a constant plateau at 12-16 weeks, whereas caspase 3 exhibited a marginally enhanced expression at 8 weeks, however, reached a constant maximum peak 12-16 weeks after the beginning of spinal cord compression. It was hypothesized that, in the initial phase of spinal cord compression, enhanced p62 expression triggered NF-κB activity, directing the cell responses mainly to cell survival and autophagy, whereas following eight weeks of spinal cord compression, caspase 3 was additionally activated indicating cumulative elimination of irreversibly damaged nerve cells with highly activated autophagy.

A Comparison of Multilevel Anterior Cervical Discectomy and Corpectomy in Patients with 4-level Cervical Spondylotic Myelopathy: A Minimum 2-year Follow-up Study.

Study Design: Retrospective clinical series. Objectives: To compare perioperative parameters, clinical outcomes, radiographic parameters, and complication rates of segmental anterior cervical corpectomy and fusion (sACCF) plus preservation of middle vertebrae with those of multilevel anterior cervical discectomy and fusion (mACDF) in 70 patients with 4-level cervical spondylotic myelopathy (CSM). Methods: Between July 2006 and May 2011, 70 consecutive patients [49 males and 21 females; mean age 56.8 y (range, 38–72 years)] with 4-level CSM were enrolled in this study and divided into sACCF (n=39) group and mACDF (n=31) group. The study compared perioperative parameters, complication rates, clinical parameters, and radiologic parameters. Results: No significant differences between the groups were found in demographic, baseline disease characteristics, operation time, hospital stay, and follow-up time. Significant improvements of clinical outcome were seen from preoperative to postoperative in both groups. Satisfaction was rated as excellent or good by 79.5% of the sACCF group and 80.6% of the mACDF group, which was not a significant difference. Mean postoperative cervical lordosis was significantly greater in the mACDF group than in the sACCF group. Blood loss was significantly greater in the sACCF group than in the mACDF group and instrumentation-related and/or graft-related complication rate significantly lower for the mACDF group. Both sACCF and mACDF groups achieved solid fusion rates (87.1% and 90.3%, respectively). Conclusions: Both mACDF and sACCF provide satisfactory clinical outcomes and fusion rates for 4-level CSM. However, mACDF is associated with better radiologic parameter, less blood loss, and lower instrumentation-related and/or graft-related complication rate.

Comparison of Two Reconstructive Techniques in the Surgical Management of Four-Level Cervical Spondylotic Myelopathy

To compare the clinical efficacy and radiological outcome of treating 4-level cervical spondylotic myelopathy (CSM) with either anterior cervical discectomy and fusion (ACDF) or “skip” corpectomy and fusion, 48 patients with 4-level CSM who had undergone ACDF or SCF at our hospital were analyzed retrospectively between January 2008 and June 2011. Twenty-seven patients received ACDF (Group A) and 21 patients received SCF. Japanese Orthopaedic Association (JOA) score, Neck Disability Index (NDI) score, and Cobbs angles of the fused segments and C2-7 segments were compared in the two groups. The minimum patient follow-up was 2 years. No significant differences between the groups were found in demographic and baseline disease characteristics, duration of surgery, or follow-up time. Our study demonstrates that there was no significant difference in the clinical efficacy of ACDF and SCF, but ACDF involves less intraoperative blood loss, better cervical spine alignment, and fewer postoperative complications than SCF.

A morphometric study of the lumbar spinous process in the Chinese population

Our goal was to analyze the anatomical parameters of the lumbar spine spinous process for an interspinous stabilization device designed for the Chinese population and to offer an anatomical basis for its clinical application. The posterior lumbar spines (T12-S1) of 52 adult cadavers were used for measuring the following: distance between two adjacent spinous processes (DB), distance across two adjacent spinous processes (DA), thickness of the central spinous processes (TC), thickness of the superior margin of the spinous processes (TS), thickness of the inferior margin of the spinous processes (TI), and height of the spinous processes (H). Variance and correlation analyses were conducted for these data, and the data met the normal distribution and homogeneity of variance. DB decreased gradually from L1-2 to L5-S1. DA increased from T12-L1 to L2-3 and then decreased from L2-3 to L4-5. The largest H in males was noted at L3 (25.45±5.96 mm), whereas for females the largest H was noted at L4 (18.71±4.50 mm). Usually, TS of the adjacent spinous process was lower than TI. Based on the anatomical parameters of the lumbar spinous processes obtained in this study, an “H”-shaped coronal plane (posterior view) was proposed as an interspinous stabilization device for the Chinese population. This study reports morphometric data of the lumbar spinous processes in the Chinese population, which provides an anatomical basis for future clinical applications.