Objective To analyze the biomechanical changes of the adjacent cervical facet joints when the angled cervical prosthesis is replaced. Methods A total of 400 northwestern people were involved, with an age of 40 years or older.The cervical vertebra lateral X-ray films were taken, and the cervical angles were measured by professional computer aided design software, then the cervical intervertebral disc prosthesis with 10° angle was designed. The finite element models of C4，5and C4-6 segments with intact cervical discs were developed; the C4，5 disc was replaced by the cervical prosthesis with 0° and 10° angle respectively; and then all models were subjected to axial loading, flexion/extension, lateral bending, and torsion loading conditions; the stress effects on adjacent facet joints after replacement were observed by comparing with that of the intact model. Results The cervical angles were (9.97 ± 3.64)° in C3，4, (9.95 ± 4.34)° in C4，5, (8.59 ± 3.75)° in C5，6, and (8.49 ± 3.39)° in C6，7, showing no significant difference between C3，4 and C4，5, C5，6 and C6，7 (P gt; 0.05) and showing significant differences between the other cervical angles (P lt; 0.05). When C4，5 model was axially loaded, no significant difference in equivalent shearing stress were observed in intact, 0°, and 10° groups; at flexion/extension loading, the stress was biggest in intact group, and was smallest in 10° group; at lateral bending, the stress got the high rank in intact group, and was minimum in 10° group; at torsion loading, the stress state of 10° group approached to the intact one condition. When C4-6 model was loaded, the facet joint stress of the replaced segment (C4，5) decreased significantly at axial loading, flexion/extension, and lateral bending; while no obvious decrease was observed at torsion loading; the stress of the adjacent inferior disc (C5，6) decreased significantly at axial loadingand lateral bending condition, while less decrease was observed at torsion loading, no significant change at flexion/extension condition, it approached to that of the intact one. Conclusion The finite element analysis reveals that the biomechanical properties of 10° designed prosthesis is approximate to that of the intact cervical disc, thus the 10° designed prosthesis can meet the requirements of biomechanical function reconstruction of the cervical spine.
Objective To study the development, investigation, and application of the artificial vertebral body so as to provide an essential reference for the future research and clinical application. Methods The recent articles on materials, types, and clinical applications of the artificial vertebral body were reviewed.Results The materials used for the artificial vertebral body were porcelain, alloy, variant bone, and composite. But each of them had its own advantages and disadvantages. The types of the artificial vertebral body were grouped as expandable and non-expandable ones; however, the expandable type was much better. The artificial vertebral body had been applied to the treatments of spinal tumor, tuberculosis, fracture, and infection, with better effects. Conclusion The artificial vertebral body can beextensively applied. However, the materials and types need to be improved.
OBJECTIVE To investigate the therapeutic effect of percutaneous lumbar discectomy (PLD) combined with sodium hyaluronate (SH) injection in the treatment of lumbar intervertebral disc herniation. METHODS Forty-eight patients suffered from lumbar disc herniation were divided into two groups and treated by PLD combined with SH injection into epidural cavity (treatment group) or single PLD (control group) respectively. All patients were followed up for 24 months. The therapeutic effects in both groups were assessed and compared according to Macnab’s criterion. RESULTS The patients in the treatment group got much more significant improvement than those in the control group, with shorter therapeutic course and more safety. CONCLUSION PLD combined with SH injection into epidural cavity is more effective and safety in the treatment of lumbar disc herniation than of pure PLD.
Objective To assess the efficacy and safety of dexmedetomidine used for intravertebral anesthesia. Methods A search in PubMed Central, EBSCO, Springer, Ovid, CNKI and WanFang Data was conducted from the date of their establishment to February 2011, so as to collect the randomized controlled trails (RCTs) on dexmedetomidine used for intravertebral anesthesia. The reference lists of identified papers were examined for further trials. After the data were extracted and the quality was assessed in accordance with the inclusion and exclusion criteria, the Meta-analysis was conducted with RevMan5.0 software. Results A total of 13 RCTs involving 672 patients were included. The results of meta-analyses showed that compared with saline solution, dexmedetomidine tended to speed up the mean time of sensory block to reach T10 dermatome (MD= –2.39, 95%CI –4.40 to –0.39) and motor block to reach Bromage 3 (MD= –5.30, 95%CI –7.18 to –3.43). It also prolonged the time for two dermatomes regression of sensory blockade (MD=51.14, 95%CI 44.96 to 57.32) and complete resolution of motor blockade (MD=68.46, 95%CI 38.56 to 98.35). Peri-operative bradycardia significantly increased (RR=3.03, 95%CI 1.64 to 5.59) but shivering decreased (RR=0.47, 95%CI 0.28 to 0.80). In comparison with the control group, dexmedetomidine showed no difference in low blood pressure and occurrence of postoperative nausea and vomiting. Conclusion The current evidence shows that dexmedetomidine shortens the time for taking effect, prolongs the duration of intravertebral anesthesia, decreases the occurrence of shivering, and increases the occurrence of bradycardia.
Objective
To compare the biomechanical properties of the anterior transpedicular screw-artificial vertebral body (AVB) and conventional anterior screw plate system (AP) in lower cervical spine by finite element study.
Methods
CT images (C1-T1) were obtained from a 38-year-old female volunteer. The models of intact C3-7 (intact group), AP fixation (AP group), and AVB fixation (AVB group) were established and analyzed by Mimics 14.0, Geomagic Studio 2013, and ANSYS 14.0 softwares. The axial force of 74 N and moment couple of 1 N·m were loaded on the upper surface and upper facet joint surfaces of C3. Under conditions of flexion, extension, lateral bending, and rotation, the Von Mises stress distribution regularity and maximum equivalent stree of AP and AVB groups were recorded, and the range of motion (ROM) was also analyzed of 3 groups.
Results
The intact model of lower cervical spine (C3-7) was established, consisting of 286 382 elements and 414 522 nodes, and it was successfully validated with the previously reported cadaveric experimental data of Panjabi and Kallemeyn. The stress concentrated on the connection between plate and screw in AP group, while it distributed evenly in AVB group. Between AP and AVB groups, there was significant difference in maximum equivalent stress values under conditions of 74 N axial force, flexion, extension, and rotation. AVB group had smaller ROM of fixed segments and larger ROM of adjacent segments than AP group. Compared with intact group, whole ROM of the lower cervical spine decreased about 3°, but ROM of C3, 4 and C6, 7 segments increased nearly 5° in both AP and AVB groups.
Conclusion
As a new reconstruction method of lower cervical spine, AVB fixation provides better stability and lower risk of failure than AP fixation.
ObjectiveTo explore the fusion effect of allograft Cages on transforaminal lumbar interbody fusion (TLIF).MethodsThe clinical data of 30 patients (38 vertebral segments) who underwent TLIF with allograft interbody fusion Cages between January 2015 and January 2017 were retrospectively analysed. There were 25 males and 5 females with an average age of 56.9 years (range, 44-72 years). The lesions included 20 cases of lumbar disc herniation, 7 cases of lumbar spondylolisthesis, and 3 cases of lumbar spinal stenosis. The operation section included 4 cases of L3, 4, 13 cases of L4, 5, 5 cases of L5, S1, 6 cases of L4, 5-L5, S1, and 2 cases of L3, 4-L4, 5. The disease duration was 6-36 months (mean, 12 months). The clinical effectiveness was evaluated by visual analogue scale (VAS) score, Oswestry disability index (ODI), and Japanese Orthopaedic Association (JOA) score at preoperation, 3 months and 6 months after operation, and last follow-up. The fusion rate was evaluated by anteroposterior and lateral X-ray films and CT three-dimensional reconstruction at 3 and 6 months after operation. The intervertebral space height was measured on anteroposterior and lateral X-ray films at preoperation, 3 days, 3 months, and 6 months after operation.ResultsThe operation time was 2.1-4.3 hours (mean, 3.1 hours), and the intraoperative blood loss was 150-820 mL (mean, 407.5 mL). The follow-up time was 8-25 months (mean, 16.4 months). One Cage split at 6 months after operation without Cage movement and neurologic symptoms; none of the other patients had Cage prolapse, displacement, and fragmentation. No local or systemic allergy or infection signs was found in all patients. No nerve compression or symptoms was observed during the follow-up. The postoperative VAS score, ODI score, and JOA score improved significantly when compared with preoperative scores (P<0.05); and the scores at 6 months and at last follow-up were significantly improved when compared with those at 3 months after operation (P<0.05); but no significant difference was found between at 6 months and at last follow-up (P>0.05). The fusion rate was 55.3% (21/38), 92.1% (35/38), and 100% (38/38) at 3 months, 6 months, and last follow-up postoperatively. The intervertebral space height was increased significantly at 3 days, 3 months, 6 months, and last follow-up postoperatively when compared with preoperative ones (P<0.05); and the loss of intervertebral space height was significant at last follow-up when compared with postoperative at 3 days (P<0.05).ConclusionThe allograft interbody fusion Cage contributes to the spine interbody fusion by providing an earlier stability and higher fusion rate.
ObjectiveTo review the biomaterial and clinical prospects of annulus fibrosus tissue engineering.
MethodsThe recent literature concerning annulus fibrosus tissue engineering, including cell source, bioactive molecules, and biomaterial was extensively reviewed and summarized.
ResultsMesenchymal stem cells (MSCs) is an ideal seed cells. When annulus fibrosus cells and MSCs in the ratio of 2:1 are cultured, it shows the closest mRNA expression levels of annulus fibrosus-related markers. Bioactive molecules can be divided into 4 types:growth factors, morphogens, catabolic enzyme inhibitors, and intracellular regulators. They play an active role in promoting the synthesis of extracellular matrix, and maintaining intervertebral disc homeostasis and a balance between anabolic- and catabolic process in the disc. Based on the source, biological materials can be divided into natural materials, synthetic materials, and composite materials. The mechanical properties of the annulus fibrosus is an important basis for material design. Up to now, none of these scaffold materials is accepted as the most suitable one. The selection of scaffold materials is still to be further studied. The development of novel composite biomaterials is a trend.
ConclusionThe annulus fibrosus tissue engineering for the anulus fibrosus regeneration and repair will bring very broad prospects for clinical application in future.
OBJECTIVE To testify the inductive osteogenesis of allogeneic bone matrix gelatin (BMG) in promoting intervertebral fusion. METHODS The gelatin sponge, allogeneic BMG, decalcified bone matrix (DBM) and alcohol conserved bone were implanted respectively into the intervertebral space of rabbit, whose intervertebral discs were removed before implantation. The intervertebral spaces were evaluated by X-ray and histological examination at 4, 8, and 12 weeks after operation. RESULTS No obvious immune rejection was observed. Amounts of new bone were formed in the intervertebral spaces at 4 and 8 weeks. And complete infusion of the intervertebral spaces were appeared at 12 weeks. CONCLUSION Allogeneic BMG can promote bone fusion of intervertebral spaces through osteoinduction, which suggests that allogeneic BMP is an ideal substitute for bone replacement.
ObjectiveTo investigate the safety and effectiveness of pedicle screw implantation via vertebral arch-transverse pathway in clinical application by a prospective randomized controlled trial.MethodsTwenty-four patients who were admitted between May 2015 and June 2017 and met the selection criteria for thoracic pedicle screw fixation were included in the study. According to the random number table method, they were divided into the trial group (screw implantation via vertebral arch-transverse pathway) and the control group (traditional screw implantation technology), with 12 patients in each group. There was no significant difference between the two groups in age, gender, cause of injury, injured segment, and the interval between injury and operation (P>0.05). The time of screw implantation was recorded and compared between the two groups. The acceptable rate of screw implantation and the penetration rate of pedicle wall were calculated after operation.ResultsThe time of screw implantation of trial group was (5.08±1.74) minutes, which was significantly shorter than that of control group [(5.92±1.66) minutes], and the difference was significant (t=4.258, P=0.023). Patients in both groups were followed up 1-2 years, with an average of 1.5 years. During the follow-up, no failure of internal fixation occurred. At 1 week after operation, the screw implantation in trial group was rated as gradeⅠin 54 screws, gradeⅡ in 3 screws, and grade Ⅲ in 2 screws, with the acceptable rate of 93.61%. The screw implantation in control group was rated as gradeⅠin 40 screws, grade Ⅱin 10 screws, grade Ⅲ in 8 screws, and grade Ⅳ in 1 screw, with the acceptable rate of 84.75%. There was significant difference in the acceptable rate of screw implantation between the two groups (χ2=3.875, P=0.037). The penetration rate of pedicle wall in trial group was 8.47% (5/59), which was significantly lower than that in the control group [32.20% (19/59); χ2=4.125, P=0.021].ConclusionCompared with the traditional technique, the pedicle screw implantation via vertebral arch-transverse pathway can obtain a good position of the screw canal with higher accuracy and simpler operation.
Objective From the viewpoint of health economics, to analyse the cost-utility of Coflex interspinous dynamic reconstruction and 360° fusion in the treatment of single level lumbar degenerative disease, so as to provide references to doctors and patients for making the best solution. Methods From October 2008 to November 2010, a prospective non-randomized controlled study was carried out on the patients diagnosed as L4-L5 degenerative lumbar spinal disorders, of whom Group A were treated by posterior decompression combined with Coflex interspinous dynamic reconstruction and Group B accepted lumbar 360° fusion treatment. The SF-36 questionnaire was used to survey the life quality of patients and to calculate the quality-adjusted life year (QALY); meanwhile, the costs of the treatment were collected to compare the cost-utility ratio between the two groups. Results A total of 60 patients were included, among whom 29 patients including 20 males and 9 females were in Group A, and the other 31 patients including 16 males and 15 females were in Group B; and the mean time of follow-up was 16.4 months (12-23 months). The average age of Group A and Group B was 45.1 years (21-67 years) and 56.2 years (32-86 years), respectively; the medical costs were 51 509.9±2 422.9 yuan and 57 409.7±9 072.9 yuan, respectively; the life quality compared with that of pre-operation improved by 42.60% and 42.82%, respectively; the cost-utility ratios were 69165.6±4716.0 yuan/QALY and 77 976.7±12 757.4 yuan/QALY, respectively. For each increase of one QALY, Group A could save 12.74% of the cost compared with Group B. Conclusion Coflex interspinous dynamic reconstruction has the equal short-term effects to lumbar 360° fusion in the treatment of L4-L5 degenerative lumbar spinal disorders, but it has lower costs than the latter, and is more in line with the requirements of health economics.
