Use of demineralized bone matrix in spinal fusion

Spinal fusion remains the gold-standard treatment for several pathological spine conditions. Although, autologous Iliac Crest Bone Grafting is considered the goldstandard graft choice to promote spinal fusion; however, it is associated with significant donor site morbidity and a limited graft quantity. Therefore, several bone graft alternatives have been developed, to augment arthrodesis. The purpose of this review is to present the results of clinical studies concerning the use of demineralized bone matrix(DBM), alone or as a composite graft, in the spinal fusion. A critical review of the English-language literature was conducted on Pubmed, using key word "demineralized bone matrix", "DBM", "spinal fusion", and "scoliosis". Results had been restricted to clinical studies. The majority of clinical trials demonstrate satisfactory fusion rates when DBM is employed as a graft extender or a graft enhancer.Limited number of prospective randomized controlled trials(4 studies), have been performed comparing DBM to autologous iliac crest bone graft in spine fusion. The majority of the clinical trials demonstrate comparable efficacy of DBM when it used as a graft extender in combination with autograft, but there is no clinical evidence to support its use as a standalone graft material. Additionally, high level of evidence studies are required, in order to optimize and clarify the indications of its use and the appropriate patient population that will benefit from DBM in spine arthrodesis.

Spinal fusion-hardware construct: Basic concepts and imaging review

The interpretation of spinal images fixed with metallic hardware forms an increasing bulk of daily practice in a busy imaging department. Radiologists are required to be familiar with the instrumentation and operative options used in spinal fixation and fusion procedures, especially in his or her institute. This is critical in evaluating the position of implants and potential complications associated with the operative approaches and spinal fixation devices used. Thus, the radiologist can play an important role in patient care and outcome. This review outlines the advantages and disadvantages of commonly used imaging methods and reports on the best yield for each modality and how to overcome the problematic issues associated with the presence of metallic hardware during imaging. Baseline radiographs are essential as they are the baseline point for evaluation of future studies should patients develop symptoms suggesting possible complications. They may justify further imaging workup with computed tomography, magnetic resonance and/or nuclear medicine studies as the evaluation of a patient with a spinal implant involves a multi-modality approach. This review describes imaging features of potential complications associated with spinal fusion surgery as well as the instrumentation used. This basic knowledge aims to help radiologists approach everyday practice in clinical imaging.

ANTERIOR SPINAL FUSION WITH TSRH INSTRUMENTATION FOR SCOLIOSIS

Objective. To introduce a new spinal internal fixation system, Texas Scottish Rite Hospital (TSRH), and to investigate its early clinical outcomes.Methods. The preliminary clinical outcomes of 15 patients with thoracolumbar or lumbar scoliosis treated by anterior spinal fusion with TSRH instrumentation were studied retrospectively. Fourteen patients were diagnosed as idiopathic scoliosis and 1 as neuromuscular scoliosis.Results. Preoperatively, the Cobb's angle on the coronal plane was 55. 8° (range 35° - 78°), and 14° postoperatively, with an average correction of 74. 8 %. The average unfused thoracical curve was 35. 9 ° preoperatively (range 26° - 51°) and 21. 8° (10°-42° ) postoperatively, with 40% correction. The sagittal curve of lumbar was kept physiologically, preoperative 27. 9° and postoperative 25. 7° respectively. The trunk shift was 13.4 mm (5 - 28mm) preoperatively and 3. 5 mm (0-7 mm) postoperatively. The averaged apic vertebra derivation was 47. 8 mm (21 - 69 mm) before operation and 10. 8 mm (3-20 mm) after operation. The distance of C7 to center sacrum vertical line (CSVL) was 19. 5 mm(16 - 42)preoperatively and 11. 3 mm (0-32 mm) postoperatively. The apical vertebra rotation was 3 degree in 15 patients preoperatively, and were improved to normal in 10 patients, 1 degree in 4 patients, and 2 degree in 1 patients postoperatively. None had neurological injury and infection. Only 1 patient complained a cool feeling in the low extremity of concave side, and the symptom vanished at 3-month followed up.Conclusion. If used appropriately, TSRH anterior spinal system is a good treatment for low thoracic or thoracic lumbar scoliosis.

Efficacy and safety of different anti-osteoporotic drugs for the spinal fusion surgery: A network meta-analysis

BACKGROUND Administering anti-osteoporotic agents to patients perioperatively is a widely accepted approach for improving bone fusion rates and reducing the risk of complications.The best anti-osteoporotic agents for spinal fusion surgery remain unclear.AIM To investigate the efficacy and safety of different anti-osteoporotic agents in spinal fusion surgery via network meta-analysis.METHODS Searches were conducted in four electronic databases(PubMed,EMBASE),Web of Science,the Cochrane Library and China National Knowledge Infrastructure(CNKI)from inception to November 2022.Any studies that compared antiosteoporotic agents vs placebo for spinal fusion surgery were included in this network meta-analysis.Outcomes included fusion rate,Oswestry disability index(ODI),and adverse events.Network meta-analysis was performed by R software with the gemtc package.RESULTS In total,13 randomized controlled trials were included in this network metaanalysis.Only teriparatide(OR 3.2,95%CI:1.4 to 7.8)was more effective than placebo in increasing the fusion rate.The surface under the cumulative ranking curve(SUCRA)of teriparatide combined with denosumab was the highest(SUCRA,90.9%),followed by teriparatide(SUCRA,74.0%),zoledronic acid(SUCRA,43.7%),alendronate(SUCRA,41.1%)and risedronate(SUCRA,35.0%).Teriparatide(MD-15,95%CI:-28 to-2.7)and teriparatide combined with denosumab(MD-20,95%CI:-40 to-0.43)were more effective than placebo in decreasing the ODI.The SUCRA of teriparatide combined with denosumab was highest(SUCRA,90.8%),followed by teriparatide(SUCRA,74.5%),alendronate(SURCA,52.7),risedronate(SURCA,52.1%),zoledronic acid(SURCA,24.2%)and placebo(SURCA,5.6%)for ODI.The adverse events were not different between groups.CONCLUSION This network meta-analysis suggests that teriparatide combined with denosumab and teriparatide alone significantly increase the fusion rate and decrease the ODI without increasing adverse events.Based on current evidence,teriparatide combined with denosumab or teriparatide alone is recommended to increase the fusion rate and to reduce ODI in spinal fusion patients.

The Outcome of Posterior Spinal Fusion and Instrumentation of Adolescent Idiopathic Scoliosis without Wound Suction Drainage

Background: In spine surgery postoperative closed suction drainage is used to decrease the potential risks of wound hematoma formation, and reduces the risk of infection, cord compression and neurologic deficit. However, the efficacy of drains used for this purpose in adolescent idiopathic scoliosis is controversial. The purpose of this study is to evaluate outcomes of patients after posterior spinal fusion with instrumentation for adolescent idiopathic scoliosis without wound suction drainage. Methods: A total of 66 Patients who underwent posterior spinal fusion and instrumentation for the correction of Adolescent idiopathic scoliosis without the use of drain from January 2012 to January 2021 were included. Wound dehiscence, wound hematoma, infection, preoperative and postoperative hemoglobin levels and need for transfusion were described as frequency and mean values. Results: The average age was 15.06 years. Hospital stay was 2.2 days. Patients were followed-up over 50.21 months. There was no deep infection, wound hematoma. The difference between just postoperative and three days after operation hemoglobin levels was not significant and no need for transfusion. Only 3 (4.5%) cases with superficial skin infection and 4 (6%) cases with skin and Wound dehiscence were treated with dressing and antibiotics with full recovery. Conclusion: Without using drain for patients with idiopathic scoliosis who underwent posterior spinal fusion and instrumentation, no increase in blood loss, transfusion requirements, wound infection, skin dehiscence, and wound hematoma was observed.

Spinal fusion is an aerosol generating procedure

BACKGROUND Transmission of severe acute respiratory syndrome coronavirus 2 can occur during aerosol generating procedures.Several steps in spinal fusion may aerosolize blood but little data exists to quantify the risk this may confer upon surgeons.Aerosolized particles containing infectious coronavirus are typically 0.5-8.0μm.AIM To measure the generation of aerosols during spinal fusion using a handheld optical particle sizer(OPS).METHODS We quantified airborne particle counts during five posterior spinal instrumentation and fusions(9/22/2020-10/15/2020)using an OPS near the surgical field.Data were analyzed by 3 particle size groups:0.3-0.5μm/m^(3),1.0-5.0μm/m^(3),and 10.0μm/m^(3).We used hierarchical logistic regression to model the odds of a spike in aerosolized particle counts based on the step in progress.A spike was defined as a>3 standard deviation increase from average baseline levels.RESULTS Upon univariate analysis,bovie(P<0.0001),high speed pneumatic burring(P=0.009),and ultrasonic bone scalpel(P=0.002)were associated with increased 0.3-0.5μm/m^(3)particle counts relative to baseline.Bovie(P<0.0001)and burring(P<0.0001)were also associated with increased 1-5μm/m^(3)and 10μm/m^(3)particle counts.Pedicle drilling was not associated with increased particle counts in any of the size ranges measured.Our logistic regression model demonstrated that bovie(OR=10.2,P<0.001),burring(OR=10.9,P<0.001),and bone scalpel(OR=5.9,P<0.001)had higher odds of a spike in 0.3-0.5μm/m^(3)particle counts.Bovie(OR=2.6,P<0.001),burring(OR=5.8,P<0.001),and bone scalpel(OR=4.3,P=0.005)had higher odds of a spike in 1-5μm/m^(3)particle counts.Bovie(OR=0.3,P<0.001)and drilling(OR=0.2,P=0.011)had significantly lower odds of a spike in 10μm/m^(3)particle counts relative to baseline.CONCLUSION Several steps in spinal fusion are associated with increased airborne particle counts in the aerosol size range.Further research is warranted to determine if such particles have the potential to contain infectious viruses.Previous research has shown that electrocautery smoke may be an inhalation hazard for surgeons but here we show that usage of the bone scalpel and high-speed burr also have the potential to aerosolize blood.

Evaluation of current surgeon practice for patients undergoing lumbar spinal fusion surgery in the United Kingdom

AIM: To ascertain current surgeon practice in the United Kingdom National Health Service for the management of patients undergoing lumbar spinal fusion surgery. METHODS: Descriptive survey methodology utilised an online questionnaire administered through SurveyMonkey. Eligible participants were all surgeons currently carrying out lumbar spinal fusion surgery in the National Health Service. Two previous surveys and a recent systematic review informed questions. Statistical analyses included responder characteristics and pre-planned descriptive analyses. Open question data were interpreted using thematic analysis.RESULTS: The response rate was 73.8%. Most surgeons(84%) were orthopaedic surgeons. Range of surgeon experience(1-15 years), number of operations performed in the previous 12 mo(4-250), and range of information used to predict outcome was broad. There was some consistency of practice: most patients were seen preoperatively; all surgeons ensured patients are mobile within 3 d of surgery; and there was agreement for the value of post-operative physiotherapy. However, there was considerable variability of practice: variability of protocols, duration of hospital stay, use of discharge criteria, frequency and timing of outpatient follow up, use of written patient information and outcome measures. Much variability was explained through patient-centred care, for example, 62% surgeons tailored functional advice to individual patients. CONCLUSION: Current United Kingdom surgeon practice for lumbar spinal fusion is described. The surgical procedure and patient population is diverse, and it is therefore understandable that management varies. It is evident that care should be patient-centred. However with high costs and documented patient dissatisfactionit is important that further research evaluates optimal management.

Investigational growth factors utilized in animal models of spinal fusion: Systematic review

BACKGROUND Over 400000 Americans annually undergo spinal fusion surgeries, yet up to 40%of these procedures result in pseudoarthrosis even with iliac crest autograft, the current "gold standard" treatment. Tissue engineering has the potential to solve this problem via the creation of bone grafts involving bone-promoting growth factors(e.g., bone morphogenetic protein 2). A broad assessment of experimental growth factors is important to inform future work and clinical potential in this area. To date, however, no study has systematically reviewed the investigational growth factors utilized in preclinical animal models of spinal fusion.AIM To review all published studies assessing investigational growth factors for spinal fusion in animal models and identify promising agents for translation.METHODS We conducted a systematic review of the literature using PubMed, Embase,Cochrane Library, and Web of Science databases with searches run on May 29 th,2018. The search query was designed to include all non-human, preclinical animal models of spinal fusion reported in the literature without a timespan limit. Extracted data for each model included surgical approach, level of fusion,animal species and breed, animal age and sex, and any other relevant characteristics. The dosages/sizes of all implant materials, spinal fusion rates,and follow-up time points were recorded. The data were analyzed and the results reported in tables and text. PRISMA guidelines were followed for this systematic review.RESULTS Twenty-six articles were included in this study, comprising 14 experimental growth factors: AB204(n = 1); angiopoietin 1(n = 1); calcitonin(n = 3);erythropoietin(n = 1); basic fibroblast growth factor(n = 1); growth differentiation factor 5(n = 4), combined insulin-like growth factor 1 +transforming growth factor beta(n = 4); insulin(n = 1); NELL-1(n = 5); noggin(n= 1); P-15(n = 1); peptide B2 A(n = 2); and secreted phosphoprotein 24(n = 1).The fusion rates of the current gold standard treatment(autologous iliac crest bone graft, ICBG) and the leading clinically used growth factor(BMP-2) ranged widely in the included studies, from 0-100% for ICBG and from 13%-100% for BMP-2. Among the identified growth factors, calcitonin, GDF-5, NELL-1, and P-15 resulted in fusion rates of 100% in some cases. In addition, six growth factors-AB204, angiopoietin 1, GDF-5, insulin, NELL-1, and peptide B2 A-resulted in significantly enhanced fusion rates compared to ICBG, BMP-2, or other internal control in some studies. Large heterogeneity in animal species, fusion method,and experimental groups and time points was observed across the included studies, limiting the direct comparison of the growth factors identified herein.CONCLUSION Several promising investigational growth factors for spinal fusion have been identified herein; directly comparing the fusion efficacy and safety of these agents may inform clinical translation.

Acute spinal subdural haematoma complicating a posterior spinal instrumented fusion for congenital scoliosis:A case report

BACKGROUND Acute spinal subdural haematoma(ASSH)is a rare and potentially devastating condition with a variable prognosis.Previously described subdural haematomas were thought to have occurred spontaneously or be related to major or minor iatrogenic or traumatic injuries caused by surgery,spinal puncture or epidural anaesthesia.Other contributing pathologies have been described,such as intradural tumours or spinal arteriovenous malformations.ASSH has also been associated with anticoagulation therapy,haemostatic abnormalities and risk factors such as pregnancy.To the best of our knowledge,this case study described the first reported occurrence of an ASSH during spinal surgery in a paediatric patient.The patient was not known to have any coagulopathies,and no obvious vascular lesions were documented.The surgical procedure did not directly involve the dura mater,and no evident intraoperative dural tears were found.CASE SUMMARY We reported and discussed a case of ASSH complicating a posterior spinal instrumented fusion during surgery for paediatric congenital scoliosis.This condition has not been previously described.We made recommendations for facing such an occurrence,explored its aetiology in the context of malformation and discussed the benefits of neuromonitoring during scoliosis correction and the management protocol.We conducted a PubMed literature review for cases of paediatric ASSH and other closely related disorders.We reviewed recommendations regarding neuromonitoring and treatment management in such cases.CONCLUSION ASSH is a rare complication of posterior spinal instrumented fusion.Published cases are more often associated with anticoagulation therapy or coagulopathy.Neuromonitoring is strongly recommended to detect and assess neurological status,thus enabling rapid diagnosis and treatment and facilitating early spinal decompression and a return to a normal neurological status.

Epidural Blood Patch for Treatment of Postdural Puncture Headache in a Patient with Spinal Fusion and Recent Implantation of Intrathecal Pain Pump

We present an interesting case report of a 49-year-old female who presented with symptoms of post-dural puncture headache following implantation of an intrathecal pain pump. Her history was complicated by previous multi-level spinal fusion with hardware. The patient was evaluated and felt to be a candidate for epidural blood patch, which she elected to proceed with. Under fluoroscopic guidance epidural blood patch was successfully performed. Immediately following the procedure the patient noted significant improvement in the headache and six hours following the procedure was headache free and remained so at follow up three weeks later.

Adjacent Segment Disease after Long Spinal Fusion Ending at L5 for Adult Spinal Deformity: A Retrospective Cohort Study

Study Design: This is a retrospective cohort study using data from the adult spinal deformity (ASD) database of a single institution. Purpose: To investigate the incidence of proximal junctional failure and distal junctional failure (DJF) after ASD surgery with a lower instrumented vertebra (LIV) at L5. Overview of Literature: Spinopelvic fixation from the lower thoracic vertebra to the pelvis is the current gold standard treatment for ASD. However, the LIV at L5 is acceptable in some cases. Methods: Fifty-six patients who underwent corrective surgery for ASD with LIV at L5 were included. The upper instrumented vertebra (UIV) was T7 in one patient, T9 in 14, T10 in three, T11 in four, T12 in eight, L1 in 10, and L2 in 16. Regarding clinical parameters, age, sex, curve types of Scoliosis Research Society-Schwab classification, number of levels fused, follow-up period, hip bone mallow density, revision surgery rate, and radiographic measurements were compared between the T (UIV: T7 - 10) and TL (UIV: T11 - L2) groups. Results: The revision surgery rate was 19.6% overall. In the T and TL groups, it was 27.8%, and 15.8%, respectively (p = 0.305). The rate of DJF in the T group (33.3%) was significantly higher than in the TL group (5.3%). The rate of proximal junctional kyphosis in the T group (55.6%) was higher than in the TL group (28.9%), with no significant difference. The mean global alignment, sagittal vertical axis, and C7 plumb line-central sacral vertical line were not different between both groups. Conclusions: ASD surgery with LIV set at L5 and UIV set at the thoracic vertebrae (T7 - T10) has a risk of adjacent segment disease.

Spinal Decompression with 360&deg;Instrumented Fusion for Unstable Tuberculous Quadriplegia in a Young Adult—A Case Report

Background: Tuberculosis of the spine is common in Nigeria. It commonly causes neurological deficit especially when the lesions are higher up in the spine. Objective: To report a case of a young man who had C4 quadriplegia from tuberculous destruction of C3 to C5 vertebral bodies and their intervening discs, aretropharyngeal prevertebral abscess and associated segmental kyphosis. He had received prior antituberculous therapy with no improvement. Results: He recovered completely neurologically when he had adequate decompression and 360°;instrumented fusiondone in a 3-stage surgery that involved drainage and debridement of the retropharyngeal prevertebral abscess, anterior corpectomy of C3 and C4 with fusion using a titanium mesh cage, and posterior fusion of C3 to C6 using titanium rods and lateral mass screws. Surgical treatment was supported with skull traction and antituberculous therapy. Conclusion: This case shows that complete neurologic recovery is feasible in spinal quadriplegia that fails to respond to antituber-culous therapy when adequate decompression and fusion are done.

斜外侧椎间融合联合侧方钢板固定治疗单节段腰椎退变性疾病的短期疗效

背景:单纯斜外侧椎间融合术融合器沉降并发症率高,辅助后方的固定可以提供稳定的支撑,但术中体位变化、双切口都弱化了该技术的微创优势。斜外侧椎间融合术联合侧方钢板固定可以实现一期同切口完成减压,同时侧方内固定提供了稳定支撑。目的:分析斜外侧椎间融合联合侧方钢板固定治疗单节段腰椎退变性疾病的短期临床疗效。方法:收集2020年5月至2022年10月应用斜外侧椎间融合联合侧方钢板固定治疗单节段腰椎退变性疾病34例患者的临床资料,其中男14例,女20例;年龄41-72岁,平均(58.6±9.9)岁;腰椎滑脱症(Ⅰ度)11例,腰椎间盘突出症并节段不稳7例,腰椎管狭窄症16例。记录患者手术时间、出血量及并发症。评估术前、术后3个月及末次随访腰痛及双下肢放射痛疼痛目测类比评分和Oswestry功能障碍指数评分;测量并观察手术前后硬膜囊面积、椎间隙高度及椎间融合情况。结果与结论:(1)34例患者随访14-36个月,平均(21.3±5.2)个月;(2)手术时间50-92 min,平均(68.5±11.1)min;术中出血量50-170 mL,平均(71.6±25.3)mL;(3)与术前相比,术后3个月及末次随访目测类比评分和Oswestry功能障碍指数评分均显著降低,差异均有显著性意义(P<0.001),最大Oswestry功能障碍指数评分改善近50%;(4)术后半年随访所有患者均达到骨性融合,总体并发症发生率为21%(7/34),其中钢板移位1例、融合器下沉3例、术侧腰大肌无力1例、术侧大腿前侧疼痛2例;(5)提示斜外侧椎间融合联合侧方钢板固定治疗单节段腰椎退变性疾病,具有出血量少、手术时间短、术后恢复快的特点,短期临床疗效显著且可提供一定稳定支撑,长期疗效有待进一步随访观察。

一种新型压配式腰椎椎间融合器的机械性能

背景:行经皮微创椎间孔腰椎椎间融合置入椎间融合器时,由于入路操作范围狭窄,有牵拉神经根损伤或置入融合器位置不良等风险,为了解决以上问题作者课题组发明了一种新型机械结构可变形压配式cage(Press-fit cage,YP-cage)。目的:对新型腰椎融合器YP-cage的机械强度特性进行初步评估。方法:对不同尺寸9,11,13 mm高度的新型YP-cage(n=9)和聚醚醚酮-cage(n=9)进行了静态轴向压缩实验和静态轴向扭转实验,分别采集力-位移曲线计算屈服位移及载荷、极限载荷位移及刚度,屈服角位移及扭矩、极限载荷角位移扭矩及刚度,并进行对比分析。结果与结论:(1)在静态轴向压缩测试中,YP-cage在3组测试中(9,11,13 mm),其刚度、屈服载荷、极限位移和载荷极限方面均优于聚醚醚酮-cage(P <0.01),但YP-cage的屈服位移小于聚醚醚酮-cage(P <0.05);(2)在静态扭转测试中,除了9 mm组的YP-cage和聚醚醚酮-cage在极限扭转角度上差异无显著性意义,YP-cage在屈服扭矩、屈服扭转角度及极限扭矩均小于聚醚醚酮-cage(P <0.01),而YP-cage扭转刚度在9 mm组和11 mm组大于聚醚醚酮-ccage(P <0.01);(3)结果表明新型压配式机械结构椎间融合器相较于聚醚醚酮材质cage具有更高的抗压强度,但抗扭强度不如聚醚醚酮-cage。

Current strategies for the restoration of adequate lordosis during lumbar fusion

Not restoring the adequate lumbar lordosis during lumbar fusion surgery may result in mechanical low back pain, sagittal unbalance and adjacent segment degeneration. The objective of this work is to describe the current strategies and concepts for restoration of adequate lordosis during fusion surgery. Theoretical lordosis can be evaluated from the measurement of the pelvic incidence and from the analysis of spatial organization of the lumbar spine with 2/3 of the lordosis given by the L4-S1 segment and 85% by the L3-S1 segment. Technical aspects involve patient positioningon the operating table, release maneuvers, type of instrumentation used(rod, screw-rod connection, interbody cages), surgical sequence and the overall surgical strategy. Spinal osteotomies may be required in case of fixed kyphotic spine. AP combined surgery is particularly efficient in restoring lordosis at L5-S1 level and should be recommended. Finally, not one but several strategies may be used to achieve the need for restoration of adequate lordosis during fusion surgery.

Effect of Graphene Nanoribbons (TexasPEG) on locomotor function recovery in a rat model of lumbar spinal cord transection

A sharply transected spinal cord has been shown to be fused under the accelerating influence of membrane fusogens such as polyethylene glycol （PEG） （GEMINI protocol）. Previous work provided evidence that this is in fact possible. Other fusogens might improve current results. In this study, we aimed to assess the effects of PEGylated graphene nanoribons （PEG-GNR, and called ＂TexasPEG＂ when prepared as lwt% dispersion in PEG600） versus placebo （saline） on locomotor function recovery and cellular level in a rat model of spinal cord transection at lumbar segment 1 （L1） level. In vivo and in vitro experiments （n -- 10 per experiment） were designed. In the in vivo experiment, all rats were submitted to full spinal cord transection at L1 level. Five weeks later, behavioral assessment was performed using the Basso Beattie Bresnahan （BBB） locomotor rating scale. Immunohistochemical staining with neuron marker neurofilament 200 （NF200） antibody and astrocyt- ic scar marker glial fibrillary acidic protein （GFAP） was also performed in the injured spinal cord. In the in vitro experiment, the effects of TexasPEG application for 72 hours on the neurite outgrowth of SH-SYSY cells were observed under the inverted microscope. Results of both in vivo and in vitro experiments suggest that TexasPEG reduces the formation of glial scars, promotes the regeneration of neurites, and thereby contributes to the recovery of locomotor function of a rat model of spinal cord transfection.

Animal Modelling of Lumbar Corpectomy and Fusion and in vivo Growth of Spine Supporting Bone by Titanium Cage Implants: An Experimental Study

In this study a lumbar spinal fusion animal model is established to assess the effect of spinal fusion cage,and explore theminimum area ratio of titanium cage section to vertebral section that ensures bone healing and biomechanical property.Lumbarcorpectomy was conducted by posterolateral approach with titanium cage implantation combined with plate fixation.Titaniumcages with the same length but different diameters were used.After implantation of titanium cages,the progress of bone healingwas observed and the bone biomechanical properties were measured,including deformation and displacement in axial compression,flexion,extension,and lateral bending motion.The factors affecting the in vivo growth of spine supporting body wereanalyzed.The results show that the area ratio of titanium cage section to vertebral section should reach 1/2 to ensure the bonehealing,sufficient bone intensity and biomechanical properties.Some bone healing indicators,such as BMP,suggest that there isa relationship between the peak time and the peak value of bone formation and metabolism markers and the bone healing strength.

Anterior Lumbar Intervertebral Fusion with Artificial Bone in Place of Autologous Bone

The feasibility of anterior lumbar intervertebral fusion with artificial bone in place of autogenous bone was investigated Porous hydroxyapatite(HA)/ZrO 2 ceramics loading bone morphogenetic protein (BMP) were implanted after removal of lumbar vertebral disc in rabbits The adjacent intervertebral discs were also removed by the same way and autogenous illic bone was implanted SEM observation and biomechanical test were carried out Compound bone had a bit lower osteoinductive activity than autogenous bone by SEM(Osteoindutive activity of artificial bone in 12 weeks was the same as that of autogenous bone in 9 weeks) Biomechanical test revealed that compound bone had lower anti-pull strength than autogenous bone ( P< 0 001), but there was no significant difference in anti-pull strength between compound bone at 12th week and autogenous bone at 9th week (P>0 05) It was concluded that compound bone could be applied for anterior spinal fusion, especially for those patients who can't use autogenous bone

Successful outcomes of unilateral vs bilateral pedicle screw fixation for lumbar interbody fusion:A meta-analysis with evidence grading

BACKGROUND Whether it’s better to adopt unilateral pedicle screw(UPS)fixation or to use bilateral pedicle screw(BPS)one for lumbar degenerative diseases is still controversially undetermined.AIM To make a comparison between UPS and BPS fixation as to how they work efficaciously and safely in patients suffering from lumbar degenerative diseases.METHODS We have searched a lot in the databases through 2020 with index terms such as“unilateral pedicle screw fixation”and“bilateral pedicle screw fixation.”Only randomized controlled trials and some prospective cohort studies could be found,yielding 15 studies.The intervention was unilateral pedicle screw fixation;Primarily We’ve got outcomes of complications and fusion rates.Secondarily,we’ve achieved outcomes regarding total blood loss,operative time,as well as length of stay.Softwares were installed and utilized for subgroup analysis,analyzing forest plots,sensitivity,heterogeneity,forest plots,publication bias,and risk of bias.RESULTS Fifteen previous cases of study including 992 participants have been involved in our meta-analysis.UPS had slightly lower effects on fusion rate[relative risk(RR)=0.949,95%CI:0.910 to 0.990,P=0.015],which contributed mostly to this metaanalysis,and similar complication rates(RR=1.140,95%CI:0.792 to 1.640,P=0.481),Δvisual analog scale[standard mean difference(SMD)=0.178,95%CI:-0.021 to 0.378,P=0.080],andΔOswestry disability index(SMD=-0.254,95%CI:-0.820 to 0.329,P=0.402).In contrast,an obvious difference has been observed inΔJapanese Orthopedic Association(JOA)score(SMD=0.305,95%CI:0.046 to 0.563,P=0.021),total blood loss(SMD=-1.586,95%CI:-2.182 to-0.990,P=0.000),operation time(SMD=-2.831,95%CI:-3.753 to-1.909,P=0.000),and length of hospital stay(SMD=-0.614,95%CI:-1.050 to-0.179,P=0.006).CONCLUSION Bilateral fixation is more effective than unilateral fixation regarding fusion rate after lumbar interbody fusion.However,JOA,operation time,total blood loss,as well as length of stay were improved for unilateral fixation.

Time representation of mitochondrial morphology and function after acute spinal cord injury

Changes in mitochondrial morphology and function play an important role in secondary damage after acute spinal cord injury. We recorded the time representation of mitochondrial morphology and function in rats with acute spinal cord injury. Results showed that mitochondria had an irregular shape, and increased in size. Mitochondrial cristae were disordered and mitochondrial membrane rupture was visible at 2–24 hours after injury. Fusion protein mitofusin 1 expression gradually increased, peaked at 8 hours after injury, and then decreased to its lowest level at 24 hours. Expression of dynamin-related protein 1, amitochondrial fission protein, showed the opposite kinetics. At 2–24 hours after acute spinal cord injury, malondialdehyde content, cytochrome c levels and caspase-3 expression were increased, but glutathione content, adenosine triphosphate content, Na＋-K＋-ATPase activity and mitochondrial membrane potential were gradually reduced. Furthermore, mitochondrial morphology altered during the acute stage of spinal cord injury. Fusion was important within the first 8 hours, but fission played a key role at 24 hours. Oxidative stress was inhibited, biological productivity was diminished, and mitochondrial membrane potential and permeability were reduced in the acute stage of injury. In summary, mitochondrial apoptosis is activated when the time of spinal cord injury is prolonged.