ObjectiveTo discuss the effect of three different ways of annulus fibrosus incision on the biomechanical strength of intervertebral disc. MethodsA total of 30 goats underwent intervertebral disc nucleus pulposus extraction at L3, 4 and L4, 5 by the working channel in group A (n=10), by circular incision in group B (n=10), and by square incision in group C (n=10). The body weight, male and female ratio, age, intraoperative blood loss, and wound healing time were recorded and compared among 3 groups. The survival rate and wound healing situation were observed after operation. At 24 weeks after operation, the goats were sacrificed, MRI images were taken to observe the signal intensity of nucleus pulposus. The disc height of L3, 4 and L4, 5 was measured to calculate the loss of disc height; biomechanical test was used to assess the strength of the disc and anulus. Histological staining was also conducted to observe the repair effect at L4, 5. ResultsThere was no significant difference in body weight, male to female ratio, age, intraoperative blood loss, and wound healing time among groups (P>0.05). All goats survived to the end of the experiment. MRI examination showed decreased signal intensity in 3 groups, indicating intervertebral disc degeneration. According to modified Thompson classification method, the degree of intervertebral disc degeneration of group A was significantly higher than that of groups B and C (P<0.05), but no significant difference was found between groups B and C (P>0.05). Difference was not significant in intervertebral space height before operation among 3 groups (P>0.05). But after 24 weeks, the intervertebral space height in group A was significantly higher than that in groups B and C (P<0.05), and the intervertebral space height loss in group A was significantly lower than that in groups B and C (P<0.05). The biomechanical strength in group A was also significantly higher than that in groups B and C (P<0.05), but no significant difference was found between group B and group C (P>0.05). HE and Masson staining showed good continuity of annulus fibrosus and clear layers in group A; poor continuity of annulus fibrosus and obvious scar tissues were observed in groups B and C. ConclusionApplication of working channel may have less destruction of annulus fibrosus, it plays a positive role in the maintenance of biomechanical strength and repair of annulus fibrosus.
Objective To summarize the role of cellular senescence and senescent secretary phenotype in the intervertebral disc (IVD) degeneration. Methods Relevant articles that discussed the roles of cellular senescence in the IVD degeneration were extensively reviewed, and retrospective and comprehensive analysis was performed. The senescent phenomenon during IVD degeneration, senescent secretary phenotype of the disc cells, senescent pathways within the IVD microenvironment, as well as the anti-senescent approaches for IVD regeneration were systematically reviewed. Results During aging and degeneration, IVD cells gradually and/or prematurely undergo senescence by activating p53-p21-retinoblastoma (RB) or p16INK4A-RB senescent pathways. The accumulation of senescent cells not only decreases the self-renewal ability of IVD, but also deteriorates the disc microenvironment by producing more inflammatory cytokines and matrix degrading enzymes. More specific senescent biomarkers are required to fully understand the phenotype change of senescent disc cells during IVD degeneration. Molecular analysis of the senescent disc cells and their intracellular signaling pathways are needed to get a safer and more efficient anti-senescence strategy for IVD regeneration. Conclusion Cellular senescence is an important mechanism by which IVD cells decrease viability and degenerate biological behaviors, which provide a new thinking to understand the pathogenesis of IVD degeneration.
Objective To design an open shape memory alloy artificial vertebral body that can be used to reconstruct the vertebral body in spine diseases, such as thoracic-lumbar spine tumors, burst fracture of the vertebrae, kyphosis and scol iosis, and to evaluate the biomechanical stabil ity of lumbar functional segment unit after insertion with the shape memoryalloy artificial vertebral body. Methods The open shape memory alloy artificial vertebral body with nickel-titanium (NiTi)alloy was made. Eight fresh spine specimens (T14-L5) from normal adult porcine were used to detect the range of motion (ROM) in 4 models and were divided into 4 groups: intact vertebrae served as group A; pedicle screw fixation of T15, L1, L3, and L4 was given in group B; after total resection of L2, it was reconstructed by open shape memory alloy artificial vertebral body combined with pedicle screw fixation of T15, L1, L3, and L4 in group C; and after total resection of L2, it was reconstructed by titanium cage vertebral body combined with pedicle screw fixation of T15, L1, L3, and L4 in group D. The three-dimensional ROM of flexion, extension, left/right lateral bending, and left/right rotation in T15-L1, L1-3, and L3,4 segments were detected in turn by the spinal three-dimensional test machine MTS-858 (load 0-8 N?m). Results Compared with group A, groups B, C, and D had good stabil ity in flexion, extension, left/right lateral bending, and left/right rotation, showing significant differences (P lt; 0.05). There was no significant difference in the degree of each motion between group B and group C (P gt; 0.05). Group C had less degree of motion in T15-L1 and L3,4 segments than group D, showing significant differences (P lt; 0.05), but there was no significant difference in L1-3 segment (P gt; 0.05). Conclusion The open shape memory alloy artificial vertebral body has a reasonable structure and good biomechanical stabil ity, it can be used to stabil ize the spinal segment with pedicle screw fixation.
ObjectiveTo explore the safety and preliminary effectiveness of transintervertebral release, bone impaction grafting, and posterior column compressed-closing in the treatment of osteoporotic vertebral fracture combined with moderate to severe spinal kyphosis.MethodsThe clinical data of 21 elderly patients with osteoporotic vertebral fracture combined with moderate to severe spinal kyphosis were retrospectively analyzed between March 2016 and November 2017. There were 1 male and 20 females, aged 55-75 years, with an average of 64.8 years. The disease duration was 8-24 months, with an average of 13.1 months. The bone density T value ranged from ?3.4 to ?2.1, with an average of ?2.3. Lesion segments: T11 in 2 cases, T12 in 6 cases, L1 in 8 cases, L2 in 1 case, T11, 12 in 1 case, T12, L1 in 2 cases, and T12, L2 in 1 case. Preoperative neurological function was classified according to the American Spinal Injury Association (ASIA): 5 cases of grade D and 16 cases of grade E. All patients underwent transintervertebral release, bone impaction grafting, and posterior column compressed-closing. The effectiveness was evaluated by visual analogue scale (VAS) score and Oswestry dysfunction index (ODI) score before operation, at 3 months after operation, and at last follow-up. The neurological function was assessed by ASIA at last follow-up. Local kyphosis Cobb angle (LKCA), thoracic kyphosis (TK), lumbar lordosis (LL), and sagittal vertebral axis (SVA) were measured on the X-ray films of the full-length lateral spine of the patient before operation, at 1 week after operation, and at last follow-up.ResultsNo complication such as fracture of internal fixator or nerve injury occurred. LKCA, TK, and SVA were significantly improved at 1 week after operation and at last follow-up (P<0.05). There was no significant difference between at 1 week after operation and at last follow-up (P>0.05). There was no significant difference in LL before and after operation (F=3.013, P=0.057). The VAS and ODI scores were significantly improved at 3 months after operation and at last follow-up, and further improved at last follow-up when compared with the scores at 3 months after operation, showing significant differences between time points (P<0.05). Five patients with ASIA grade D neurological function recovered to grade E at 6 months after operation.ConclusionTransintervertebral release, bone impaction grafting, and posterior column compressed-closing for treating osteoporotic vertebral fracture combined with moderate to severe spinal kyphosis has definite effectiveness, strong orthopaedic ability, and minimal trauma, which can effectively restore the sagittal balance of the spine, alleviate pain, and improve the patients’ quality of life.
ObjectiveTo review the research status on the molecular basis of intervertebral disc degeneration and the repairing effect of platelet-rich plasma. MethodsThe related literature about the molecular basis of intervertebral disc degeneration and the repairing effect of platelet-rich plasma was reviewed, analyzed, and summarized. ResultsThe molecular basis of intervertebral disc degeneration includes genetic influences, cell senescence, decreased matrix production, increased degradative enzyme production, proinflammatory cytokine expression, apoptosis, and neural ingrowth. Platelet-rich plasma can release a series of growth factors to promote intervertebral disc cells proliferation, differentiation, and extracellular matrix synthesis. It can also inhibit proinflammatory effect and apoptosis. ConclusionAlthough the prospect of using platelet-rich plasma to repair intervertebral disc degeneration is encouraging, further studies are still needed.
ObjectiveTo systematically review the efficacy and safety of percutaneous endoscopic lumbar discectomy (PELD) for L5/S1 disc herniation via transforaminal approach (TF-PELD) versus interlaminar approach (IL-PELD).MethodsPubMed, EMbase, The Cochrane Library, CBM, CNKI and WanFang Data databases were electronically searched to collect randomized controlled trials (RCTs) and the cohort studies of TF-PELD versus IL-PELD for L5/S1 disc herniation from inception to October 2017. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies, then, meta-analysis was performed by using RevMan 5.3 software.ResultsA total of 1 RCT and 7 cohort studies involving 414 patients were included. The results of meta-analysis indicated that: compared with IL-PELD group, TF-PELD group had longer operative time (MD=17.42, 95%CI 12.86 to 21.97, P<0.000 01) and more frequency of intraoperative fluoroscopy (MD=8.42, 95%CI 6.18 to 10.65,P<0.000 01), respectively. However, there were no significant differences between two groups in the post-operative visual analogue scale (MD=0.01, 95%CI –0.23 to 0.25,P=0.94), the post-operative Oswestry disability index (MD=–0.46, 95%CI –2.42 to 1.49, P=0.64), the excellent and good outcomes rate (RR=1.00, 95%CI 0.89 to 1.12, P=0.96), and the rate of complications (RR=0.73, 95%CI 0.45 to 1.18, P=0.20).ConclusionCurrent evidence shows that TF-PELD and IL-PELD are equally effective and safe for L5/S1 disc herniation, but IL-PELD is superior to TF-PELD in less operative time and less radiation exposure. Due to limited quality and quantity of the included studies, more high quality studies are needed to verify above conclusion.
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.
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.
ObjectiveTo summarize the feasibility and effectiveness of endovascular treatment for vertebral artery stenosis ectopic originating from the aortic arch. MethodThe clinical data of 5 patients with vertebral artery stenosis ectopic originating from aortic arch admitted to Xuanwu Hospital of Capital Medical University from January 2020 to May 2023 were retrospectively analyzed. ResultsAll 5 patients underwent magnetic resonance angiography and CT angiography before treatment. The vertebral arteries of all patients originated from the aortic arch and were severe stenosis, with a median diameter of 1.3 mm (range, 1.1–1.5 mm) by CT angiography. All 5 patients were successfully treated with endovascular intervention. The operation time was 37–45 min, with a median of 39 min. There were no complications of vertebral artery rupture, embolism or occlusion, cerebral infarction, plaque abscission, hematoma at puncture site, pseudoaneurysm, postoperative hemorrhage, or perioperative pulmonary infection. The patients were followed-up for 13–30 months, with a median follow-up time of 20 months. The blood vessels of 5 patients remained unobstructed and no clinically significant vascular restenosis occurred. ConclusionsBased on the experiences of 5 cases of vertebral artery stenosis ectopic originating from the aortic arch, it is safe and effective to choose endovascular treatment for severe symptomatic vertebral artery stenosis. Especially, it is necessary to evaluate the stenosis degree of vertebral artery using CT angiography before treatment.
Objective To evaluate the effectiveness and safety of preoperative feeding artery occlusion on vertebral resection of invasive vertebral hemangioma. Methods The clinical data of 20 patients with invasive vertebral hemangioma who received posterior lumbar vertebral body resection, bone grafting, fusion and internal fixation between March 2010 and March 2017 were retrospectively analyzed. According to whether feeding artery occlusion was performed before operation, the patients were divided into group A (11 cases, tumor feeding artery occlusion before operation) and group B (9 cases, no tumor feeding artery occlusion before operation). There was no significant difference in gender, age, lesion segment, and disease duration between the two groups (P>0.05). The operation time, intraoperative blood loss, postoperative drainage volume, blood transfusion volume, and ambulant time after surgery, hospitalization time, and deep venous thrombosis of lower extremities were recorded and compared between the two groups. Pain improvement was evaluated by visual analogue scale (VAS) score. Results The operation time, intraoperative blood loss, blood transfusion volume, and ambulant time after surgery were significantly less in group A than those in group B (P<0.05). There was no significant difference in postoperative drainage volume and hospitalization time between the two groups (P>0.05). Five patients (3 in group A and 2 in group B) suffered from pleural tear due to intraoperative pleural adhesions. Closed thoracic drainage tubes were placed immediately after suture and extubated on 3-5 days. Both groups were followed up 1-1.5 years, with an average of 1.35 years. In group B, 1 patient died of pulmonary embolism at 7 days after operation; and 2 patients developed deep venous thrombosis of lower extremity after operation, who were treated with inferior vena cava filter and thrombolytic therapy, and recovered well after operation. The local pain of the other patients was significantly relieved after operation, and the pain disappeared at 1 month after operation. The VAS scores of the two groups at 3 days after operation were significantly improved when compared with those before operation (P<0.05). There was no significant difference in VAS scores between the two groups before operation and at 3 days after operation (P>0.05). Three patients (2 in group A and 1 in group B) who had neurological symptoms were significantly relieved after surgery. Bone healing was achieved in both groups at 1 year after operation. No fracture or loosening of internal fixator occurred during follow-up. Conclusion Nutritional artery occlusion before vertebrectomy for invasive vertebral hemangioma can effectively reduce intraoperative blood loss, operation time, perioperative blood transfusion, and other perioperative complications.