Abstract In light of the necessity for precise parameter value determination in order to meet stiffness requirements at the initial design stage of the powertrain rubber suspension main spring parameters, this paper proposes the utilisation of an orthogonal experimental analysis in conjunction with a finite element method Taguchi test, employing the Minitab software, in order to achieve comprehensive analysis. It is necessary to consider the width ( W ), length ( L ), the angle of two adjacent rubber blocks ( Ɵ ), the distance from the upper surface of the inner ring ( D ), and the diameter reduction ( r ) of the outer ring of the rubber main spring during the vulcanization of the outer ring. ABAQUS was employed to calculate the suspension stiffness, with a particular focus on the V-direction stiffness within the suspension local coordinate system. In order to achieve a closer alignment with the target stiffness value, the genetic algorithm in Matlab was utilized to optimize Pareto on the basis of the orthogonal test data. This ultimately led to the identification of the optimal combination of suspension parameters that satisfied the requisite stiffness value, thereby facilitating the early development of the suspension and reducing the overall time required for this phase of the project.
Morphine elicits a series of adverse effects including the inhibition of intestinal motility in addition to the therapeutic benefit of alleviating postoperative pain. To ascertain the role of electroacupuncture (EA) in diminishing those detrimental effects on recovery, we imitated the clinical procedures in rabbits. Morphine was given via a preimplanted cannula within spinal subarachnoid space, while the duodenal motility, respiration rate and arterial pressure were simultaneously recorded. It was found that morphine (6 mg/rabbit, IT) markedly suppressed duodenal peristalsis, decreased respiration rate throughout 90 min observation. When EA was administered together with morphine, peristalsis of the duodenum was much less inhibited (P < 0.05, vs morphine alone group), but no significant improvement of respiratory depression was noticed (P > 0.05), nor obvious change of arterial pressure in both groups. The results strongly recommend extensive application of EA in postoperative care, so as to decrease both the required dosage of morphine and the subsequent occurrence of postoperative ileus, while attaining sufficient analgesia.
The aim of this study is to determine if thoracolumbar vertebral body collapse or canal compromise (CC) is associated with reposition of bone fragment. We retrospective review medical charts of patients with thoracolumbar burst fractures from July 2010 to September 2013. The fractures were classified according to the Arbeit Fuer Osteoosynthese (AO) classification system. Neurological status was classified according to American Spinal Injury Association (ASIA). Patients were divided into two groups (reposition group and non-reposition group) according to whether the bone fragments were reposition or non-reposition after surgery. Mimics measured mid-sagittal canal diameter (MSD), transverse canal diameter (TCD), local kyphosis (LK) and calculated anterior vertebral body compression ratio (AVBCR), middle vertebral body compression ratio (MVBCR), posterior vertebral body compression ratio (PVBCR), and mid-sagittal canal diameter compression ratio (MSDCR) on the preoperative CT image. The results indicated that 55 patients were included in the study. There are 35 patients with reposition of bone fragment and 20 patients with non-reposition of bone fragment after surgery. There were significant difference on MSD (t = 3.258, P = 0.002), TCD (t = 2.197, P = 0.032), AVBCR (t = -2.063, P = 0.044), MVBCR (t = -2.526, P = 0.015), PVBCR (t = -2.211, P = 0.031), MSDCR (t = -4.975, P = 0.000) between two groups before surgery. There was a significant correlation between reposition of bone fragment and AO classification (OR = 5.251, P = 0.022), and MSDCR (OR = 7.366, P = 0.007). There was no significant correlation between reposition and AVBCR, MVBCR, PVBCR, LK, MSD and TCD. In conclusion, this study indicates that AO classification and MSDCR are predictors of reposition of bone fragment.
Objective Through an experiment in rabbits, to evaluate the role of reservation flaval ligament using different methods to prevent the epidural adhesion by observing the morphological changes and provide experiment evidences for clinic. Methods 45 adult rabbits were divided into three groups: Group A (treated with no reservation of flaval ligament), Group B (treated with reserving half flaval ligament), and Group C (treated with reserving the complete flaval ligament). Every group has 15 rabbits. At the 2th,4th and 8th weeks, the samples were obtained for gross observation, histological examinations, and the images were analysed by computer. The data were processed using SPSS11.5. Result Gross Observation and Histological Examinations, at the 2th, 4th and 8th postoperative week, there was significant difference between the group A, B and C (gross observation: F2w=4.660, F4w=8.591, F8w=31.858, P<0.05; whistological examinations: F2w=5.190, F4w=9.561, F8w=34.658, P<0.05) . Images analysis: the difference was very significant in the groups at 2th, 4th and 8th weeks (F2w=30.783, F4w=47.350, F8w=25.544,P<0.01). With time passing, the ratio became larger and larger in the same group. Conclusions Reserving the complete flaval ligament can significantly prevent the peridural adhesion from the back as a barrier, and can reduce the adhesion formed.
Key words:
Intervertebral disk displacement; Postoperative complications; Ligamentum flavum; Adhesion
Lumbar fusion is a popular surgical procedure for the treatment of degenerative lumbar disc disease; however, it may be accompanied by complications, such as cage loosening, subsidence, and non-union. This study engineered and fabricated a three-dimensional (3D)-printed anisotropic biomimetic trabecular porous Ti-6Al-4V cage for lumbar interbody fusion. The study evaluated the structural design, manufacturability, mechanical properties, and cellular functions of the fabricated structures compared to currently available interbody cages. In vitro tests assessed the biofunctionality of the 3D-printed porous cage, which revealed anisotropic biomimetic trabecular porous Ti-6Al-4V cages with 65%-85% porosity, and 600 μm pore size. The microscopy analysis of surface properties indicated in situ micro- and nano-roughness. The mechanical properties decreased progressively with increasing porosity, and the optimized frame-reinforced porous cage achieved higher compressive strength and stiffness than the fully porous fusion. The 70% 3D-printed porous frame-reinforced cage had suitable mechanical performance compared with the polyether-ether-ketone (PEEK) cage. The anisotropic biomimetic trabecular porous structures and the surface micro- and nano-roughness modifications achieved excellent biological functions in vitro. In conclusion, our fabricated 70% 3D-printed porous frame-reinforced Ti-6Al-4V cage with anisotropic biomimetic trabeculae is a promising strategy for lumbar interbody fusion.Keywords: Three-dimensional printing technology, Ti-6Al-4V interbody cage, Biomimetic trabecular structure
Objective To evaluate the clinical efficacy and minimal invasiveness of quadrant posterior distraction system in the posterior lumbar spondylolistbesis (LS) surgery.Methods Sixty-one LS paftients were randomly divided into two groups:quadrant posterior minimally invesive surgery system as invesive group (n=30) and traditional open surgery as open group (n=31).The clinical outcome of pain relief Was assessed by the scoring systems of visual analogue scale (VAS) and Oswestry disability index (ODI) for low back pain.Radiographic assessment:preoperative and 1-day,3-month and last follow-up (12 months) radiographs were analyzed including the index of relative posterior disc height. Results The scores of VAS and ODI of invasive group were less than open group at Months 3 and 12 post-operation (P 0.05).And there was only statistical significance difference within 12 months (P<0.05).At Month 12 post-operation.the fluctuating rate was slight. Condusion The minimally invasive operation with Quadrant is less traumatic to the patients traditional open operation in the protection of spinal stability,postoperative rehabilitation and radiographs.This new minimally invasive spine technique should be popularized.
Key words:
Spondylolisthesis; Vertebrae lumbar; Surgical procedures,minimally invisive
Although the central mechanisms of electroacupuncture analgesia (EAA) have been investigated, a systematic study for the involvement of neuronal populations of central nervous system (CNS) in EAA has not been well undertaken, largely due to the difficulty in tracing the neuronal pathways by traditional techniques. Recently developed c-fos expression examination by immunohistochemical method with Ab-1 antisera might be used for this purpose as a useful marker for neuronal activity in CNS. In this study, tail flick latency (TFL) was tested as an index of pain threshold in conscious rats. After unilateral electroacupuncture was applied at 'Zuan-san-li' and 'Huan-tiao', the TFL was significantly prolonged. To explore the possible involvement of certain neuronal groups of central nervous system in EAA, we examined the EAA accompanied c-fos expression throughout the neuraxis, and a lot of specific c-fos protein labelled neurons were found in lumbar spinal cord (laminae I and II), nucleus raphe magnus, nucleus raphe dorsalis, substantia grisea centralis, nucleus habenulae lateralis, nucleus habenulae medialis, nucleus medialis thalami, nucleus lateralis hypothalami, nucleus supramamillaris, nucleus supraopticus, nucleus arcuatus, nucleus preopticus medialis, nucleus amygdala, nucleus tractus diagonalis, etc. No obvious c-fos expression was shown in these areas on control rats. These results strongly suggested that the functional activation of above-mentioned nuclei by electroacupuncture was underlied in EAA action.
Objective
To discuss clinical results and effect on epidural fibrosis of preservation of ligament flavum in micro endoscopy discectomy (MED).
Methods
From January 2005 to January 2011, 206 cases which med the inclusion and exclusion criteria were treated by retrospective study method and were divided into two groups. A group was treated with standarded operation in MED; B group was treated with remaining ligament flavum in MED. The visual analogue scale(VAS), Oswestry disability index(ODI), and angle of straight leg raising(SLR) were recorded 1 day before and 4 weeks after operation. The early curative effect evaluation was achieved in the 4th week. The questionnaire survey was conducted and CT was used to evaluate epidural fibrosis and recorded score 1 year after operation.
Results
One day before operation, VAS, ODI, and SLR in A group and B group were 7.75±1.23 and 7.84±1.27, 71.8%±9.4% and 72.3%±9.1%, 25.1°±2.33° and 24.6°±2.28°, (50.59±5.59)min and (51.03±6.18)min, (43.56±8.02)mL and (42.88±8.76)mL, respectively. There were no statistical differences (t=0.512, 0.386, 0.893, 0.529, 0.574, respectively, all P values>0.05). There were no statistical differences in intraoperative complication and postoperation complication between A group and B group (χ2=0.042, 0.042, respectively, all P values>0.05). Four weeks after operation, VAS, ODI, and SLR in A group and B group were 3.13±1.24 and 2.32±1.20, 29.4%±6.7% and 23.3%±7.6%, 65.2°±4.84°and 74.4°±4.92°, respectively. There were, statistically significant differences (t= 4.741, 6.025, 13.423, respectively, all P values<0.01). On early curative effect evaluation, A group was better than B group(Z=-3.058, P<0.01). On CT score, mean of A group was 1.80, mean of A group was 1.15(Z=-5.435, P<0.05).
Conclusions
Whether or not to preserve ligament flavum in discectomy in MED, clinical symptoms have great improvement when compared with its own. While the operation of remaining ligament flavum has better outcome, less epidural fibrosis.
Key words:
Diskectomy, percutaneous; Intervertebral disc displacement; Micro endoscopic; Ligamentum flavum; Dura mater; Fibrosis
A novel protein with anti-tumor activities named malanin was isolated and purified from an endemic plant in Yunnan and Guangxi provinces. Effects of copper ion, silver ion and calcium ion on malanin and apo-malanin fluorescence spectra were studied. The results showed that copper ion leads to obvious statistic quenching of malanin and apo-malanin fluorescence. The dissociation constant of them from malanin and apo-malanin were about 2.37 X 10(-4) and 2.66 X 10(-4) mol · L(-1), respectively. The silver ion did not have quenching action on malanin fluorescence, but it had statistic quenching effect on apo-malanin fluorescence, and its dissociation constant was 2.37 X 10(-4) mol · L(-1). Calcium ion did not have quenching action on malanin and apo-malanin fluorescence. It plays an important role in keeping malanin natural conformation.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)
'/%3e%3c/defs%3e%3cpath fill='%23012169' d='M0 0h10080v5040H0z'/%3e%3cpath stroke='%23fff' stroke-width='.6' d='m0 0 6 3m0-3L0 3' clip-path='url(%23b)' transform='scale(840)'/%3e%3cpath stroke='%23e4002b' stroke-width='.4' d='m0 0 6 3m0-3L0 3' clip-path='url(%23c)' transform='scale(840)'/%3e%3cpath stroke='%23fff' stroke-width='840' d='M2520 0v2520M0 1260h5040'/%3e%3cpath stroke='%23e4002b' stroke-width='504' d='M2520 0v2520M0 1260h5040'/%3e%3cg fill='%23fff'%3e%3cuse xlink:href='%23d' x='2520' y='3780'/%3e%3cuse xlink:href='%23a' x='7560' y='4200'/%3e%3cuse xlink:href='%23a' x='6300' y='2205'/%3e%3cuse xlink:href='%23a' x='7560' y='840'/%3e%3cuse xlink:href='%23a' x='8680' y='1869'/%3e%3cuse xlink:href='%23e' x='8064' y='2730'/%3e%3c/g%3e%3c/svg%3e)