Biomechanics characteristics of four anterior cervical reconstructive techniques in the surgical management of multilevel cervical spondylotic myelopathy:a finite element model study / 中国组织工程研究

BACKGROUND:Surgical treatment is commonly used for decompressing the spinal cord in multilevel cervical spondylotic myelopathy, but the optimum anterior cervical reconstructive method has not been determined. OBJECTIVE:To compare and analyze the biomechanical characteristics of four anterior cervical reconstructive techniques in the surgical management of multilevel cervical spondylotic myelopathy utilizing the three-dimensional finite element model. METHODS:A three-dimensional finite element model of an intact C2–7 segment was developed and validated based on healthy adult male CT images. Four additional models were developed from the fusion model, including anterior cervical discectomy and fusion, anterior cervical corpectomy and fusion, anterior cervical hybrid decompression and fusion and anterior cervical discectomy and fusion with Cage alone. Von Mises stresses on the plate and the disc of adjacent levels (C2/3, C6/7) were comparatively analyzed. RESULTS AND CONCLUSION:(1) The C2/3 disc stress in flexion, extension, lateral bending and rotation condition was significantly higher than the C6/7 disc in 4 anterior cervical reconstructive techniques, and the adjacent disc stress (C2/3, C6/7) was lowest in the anterior cervical discectomy and fusion with Cage alone, and highest in the anterior cervical corpectomy and fusion. (2) The stress at the plate-screw interface was highest in the anterior cervical corpectomy and fusion, and lowest in the anterior cervical discectomy and fusion. (3) In conclusion, among the four anterior cervical reconstructive techniques for multilevel cervical spondylotic myelopathy, the anterior cervical discectomy and fusion with Cage alone makes little effect on the adjacent disc stress, which might reduce the incidence of adjacent segment disease after fusion. However, the accompanying risk of the increased incidence of cage subsidence should never be neglected.

Biomechanical change in adjacent segments after cervical fusion and non-fusion：a meta-analysis of second surgery rate / 中国组织工程研究

BACKGROUND:Adjacent segment disease is a long-term complication of anterior cervical decompression and fusion, and has been paid great attention recently. Cause of disease contains increased range of motion in surgery adjacent segment, intervertebral height loss and high intradiscal pressure. In the clinic, compared with fusion surgery, whether cervical non-fusion can effectively decrease the incidence of adjacent segment disease remains poorly understood. OBJECTIVE:To systematicaly assess the effects of cervical fusion and cervical non-fusion on adjacent segment degeneration. METHODS:We retrieved the randomized controled trial concerning cervical fusionversuscervical non-fusion to repair cervical syndrome in the Medline, PubMed, Embase and Cochrane databases from January 2000 to December 2013. This study compared the effects of two repair methods on adjacent segment disease and evaluated methodological quality of the included studies. A meta-analysis was performed using RevMan 5.2 software. Outcome indicators: second surgery was undergone due to postoperative adjacent segment disease. RESULTS AND CONCLUSION: After screening, five randomized controled trials met the inclusion criteria. There were 1 602 patients. Al patients received surgery due to cervical syndrome. 785 cases underwent anterior decompression and fusion, and 817 cases underwent intervertebral disc replacement. 1 066 patients completed al folow-up, with a total folow-up rate of 66.54%. There were 494 patients treated with anterior decompression and fusion and 572 patients with intervertebral disc replacement. A total of 68 patients underwent second surgery due to adjacent segment disease. Total second surgery rate was 6.38% (68/1 066), including 28 cases after intervertebral disc replacement and 40 cases after anterior decompression and fusion. The grade of quality evaluation of the included studies was high, including five studies with grade A. Moreover, heterogeneity was smal (I2 = 14%). Meta-analysis results revealed that the second surgery rate of adjacent segment disease was lower after cervical non-fusion than after cervical fusion, which showed significant differences (odd ratio = 0.58, 95% confidence interval: 0.35, 0.96). These results suggested that the second surgery rate of adjacent segment disease was higher after cervical fusion than after cervical non-fusion. The alterations in cervical biomechanics caused by fusion greatly affected the occurrence of adjacent segment disease.

Effects of acupuncture intervention at different stages on urinary function reconstruction of neurogenic bladder after spinal cord injury / 中国针灸

<p><b>OBJECTIVE</b>To explore the effects of early intervention of acupuncture on urinary function reconstruction of neurogenic bladder after spinal cord injury, so as to find the optimal treatment timing of acupuncture.</p><p><b>METHODS</b>Fifty-three patients of neurogenic bladder after spinal cord injury were randomly divided into a prior-to-catheter group (25 cases) and a posterior-to-catheter group (28 cases). For the prior-to-catheter group, one week before the removal of catheter, acupoints on the abdomen and back such as Guanyuan (CV 4), Zhongji (CV 3), Baliao (Shangliao (BL 31), Ciliao (BL 32), Zhongliao (BL 33), Xialiao (BL 34), Jiaji (EX-B 2) and acupoints at distal end such as Zusanli (ST 36) and Sanyinjiao (SP 6) were selected; after the catheter removal, simple method. of water column was used to measure bladder capacity pressure to classify the type of bladder, and then different acupuncture manipulations were given; intermittent catheterization was performed if condition was allowed. The posterior-to-catheter group applied identical treatment after removal of catheter as the prior-to-catheter group. The treatment was given 5 times per week; after one-month treatment, five aspects including the time of first effective urination, time of establishing reflex urination, average residual volume of urine, time of residual urine less than 100 mL and quality of life (QOL) were evaluated.</p><p><b>RESULTS</b>After treatment, the time of first effective urination, time of establishing reflex urination, average residual volume of urine and time of residual urineless than 100 mL in the prior-to-catheter group were all superior to those in the posterior-to-catheter group (all P<0. 05) ; the score of QOL was improved in two groups after treatment (both P<0. 01), but the difference between two groups was not statistically significant (P>0. 05); each index of urination function was not significant among patients with different injured segments of spinal cord (all P>0. 05).</p><p><b>CONCLUSION</b>The early intervention of acupuncture (prior to catheter) has obvious improving function on establishing balanced bladder in patients with neurogenic bladder after spinal cord injury, which is superior to acupuncture intervention after removal of catheter, however, the effects of different injured segments on establishing balanced bladder are not different.</p>

Effect of etching time and resin bond on the flexural strength of IPS e.max Press glass ceramic.

OBJECTIVE: To evaluate the effect of hydrofluoric acid (HFA) etching time and resin cement bond on the flexural strength of IPS e.max(®) Press glass ceramic. METHODS: Two hundred and ten bars, 25mm×3mm×2mm, were made from IPS e.max(®) Press ingots through lost-wax, hot-pressed ceramic fabrication technology and randomly divided into five groups with forty-two per group after polishing. The ceramic surfaces of different groups were etched by 9.5% hydrofluoric acid gel for 0, 20, 40, 60 and 120s respectively. Two specimens of each group were selected randomly to examine the surface roughness and 3-dimensional topography with atomic force microscope (AFM), and microstructure was analyzed by the field emission scanning electron microscope (FE-SEM). Then each group were subdivided into two subgroups (n=20). One subgroup of this material was selected to receive a thin (approximately 0.1mm) layer of resin luting agent (Variolink N) whereas the other subgroup remained unaltered. Half of subgroup's specimens were thermocycled 10,000 times before a 3-point bending test in order to determine the flexural strength. Interface between resin cement and ceramic was examined with field emission scanning electronic microscope. RESULTS: Roughness values increased with increasing etching time. The mean flexural strength values of group 0s, 20s, 40s, 60s and 120s were 384±33, 347±43, 330±53, 327±67 and 317±41MPa respectively. Increasing HF etching times reduced the mean flexural strength (p<0.05). However, the mean flexural strength of each group, except group 0s, increased significantly to 420±31, 435±50, 400±39 and 412±58MPa after the application of dual-curing resin cement. In the present investigation, no significant differences after thermocycling on the flexural strengths were evident. SIGNIFICANCE: Overtime HF etching could have a wakening effect on IPS e.max(®) Press glass ceramic, but resin cement bonding to appropriately etched surface would strengthen the dental ceramic.

The expression of tumor necrosis factor-α and CD68 in high-intensity zone of lumbar intervertebral disc on magnetic resonance image in the patients with low back pain.

STUDY DESIGN: Several recent studies suggest a high-intensity zone (HIZ) within the posterior annulu of lumbar intervertebral disc seen on T2-weighted magnetic resonance (MR) images represents the inflammation in the annulus, an annular tear, and/or vascular granulation tissue. It has not be reported yet whether there is the expression of tumor necrosis factor (TNF-α) and inflammatory cells appear in HIZ of intervertebral disc on MR images. OBJECTIVE: To study whether HIZ is a specific signal for the inflammatory reaction of painful intervertebral disc. SUMMARY OF BACKGROUND DATA: The presence of HIZ signal within the posterior annulus seen on sagittal T2-weighted spin-echo magnetic imaging sequences has already been used in the diagnosis of painful annular tears in the last decade. There have been studies suggesting that the presence of HIZ reflects inflammation in the annulus, an annular tear, and/or vascular granulation tissue. METHODS: Twenty-six consecutive patients with low back pain underwent MR images and discography (age range = 26-65 years; mean age = 47.5 years; 16 men, 10 women). In all the patients, HIZ appeared in the involved intervertebral discs on T2-weighted MR images. Lumbar discography was usually performed on each patient for the discs L3-L4, L4-L5, and L5-S1. All patients received posterior lumbar interbody fusion procedures. The intervertebral disc specimens contained HIZ were excised en bloc during posterior interbody fusion. The distribution of TNF-α and CD68 in the intervertebral disc specimens within HIZ on MR images from 26 consecutive patients with low back pain and in the intervertebral disc specimens from five fresh cadavers were observed. RESULTS: The histologic study of the consecutive sagittal slices of the HIZ showed a lot of proliferated small round cells and fibroblasts. There were a lot of TNF-α positive cells and some CD68 positive cells in HIZ and the number of TNF-α and CD68 positive cells in HIZ was significantly higher than that in the annulus fibrosus around HIZ and in the control (P < 0.05). CONCLUSION: The results of this study indicate that HIZ may be a specific signal for the inflammatory reaction of painful intervertebral disc.