Pedicle Screw Fixation with Kyphoplasty Decreases the Fracture Risk of the Treated and Adjacent Non-treated Vertebral Bodies:a Finite Element Analysis

Adjacent vertebral fractures are common in patients with osteoporotic vertebral compression fractures（OVCFs） after kyphoplasty.This finite element study was to examine whether short segment pedicle screw fixation（PSF） with kyphoplasty may decrease the fracture risk of the treated and adjacent non-treated vertebrae after kyphoplasty for OVCFs.By simulating cement augmentation with or without short segment pedicle screw fixation（PSF）,two tridimensional,anatomically detailed finite element models of the T10–L2 functional spinal junction were developed.The insertion of pedicle screws into the intact vertebra apparently decreased the stress distribution of the treated vertebra in vertical compression and other load situations.The stress distribution in the bone structures of the intact vertebra adjacent to the intact-screwed vertebra was much less than that in the one adjacent to the treated vertebra.The insertion of pedicle screws into the intact vertebra greatly decreased the maximum displacement of the cortical bones and cancellous bones of the vertebrae.Our results indicated that short segment PSF with kyphoplasty may decrease the fracture risk of the treated and adjacent non-treated vertebrae in the management of OVCFs.

Comparison of Clinical Outcomes of Cortical Bone Trajectory and Traditional Pedicle Screw Fixation in Posterior Lumbar Interbody Fusion

Posterior lumbar interbody fusion (PLIF) is a common surgical procedure and widely used in the treatment of lumbar degenerative disc disorders. Traditionally, posterior lumbar interbody fusion is done by using the traditional pedicle screw (PS) which offers great advantages, but at the same time it has some disadvantages which include the risk of superior facet joint violation and muscle damage. Recently, an alternative method of screw insertion via cortical bone trajectory (CBT) has been invented which has less invasive process and can be placed without the drawbacks associated with the traditional pedicle screw. However, it has to remain an interest whether CBT will provide similar or greater clinical outcomes compared to PS in PLIF. So the main aim of this review is to compare the clinical outcomes of cortical bone trajectory and traditional pedicle screw fixation in posterior lumbar interbody fusion based on the articles published on this topic. Compared to the traditional pedicle screw fixation, PLIF with CBT has similar clinical outcome based on pain intensity, ODI status and JOA score, as well as similar fusion rate and radiological evaluated complication such as loosening of screw. In addition PLIF with CBT has advantages of less facet joint violation, less blood loss, less intraoperative muscle damage and perioperative pain. On the basis of this study, we can suggest that PLIF with CBT can be considered as a reasonable alternative to PS in PLIF.

Investigation of optical reflectance from different animal vertebra along the fixation trajectory of pedicle screw in frequency domain

Accurate placement of pedicle screw(PS)is crucial in spinal surgery.Developing new real-time intra-operative monitoring and navigation methods is an important direction of clinical appli-cation research.In this paper,we studied the spectrum along the fixation trajectory of PS in frequency domain to tackle the accuracy problem.Fresh porcine vertebrae,bovine vertebrae and ovine vertebrae were measured with the near-infrared spectrum(NIR)device to obtain the reflected spectrum from the vertebrae.Along the fixation trajectory of PS,average energy from different groups was calculated and used for identifying different tissues and compared to achieve the optimal recognition factor.Compared with the time domain approach,the frequency domain method could divide the spectra measured at different tissue points into different groups more stably and accurately,which could serve as a new method to assist the PS insertion.The results gained from this study are significant to the development of hi-tech medical instruments with independent intellectual property rights.

Learning curves of robot-assisted pedicle screw fixations based on the cumulative sum test

BACKGROUND In robot-assisted(RA)spine surgery,the relationship between the surgical outcome and the learning curve remains to be evaluated.AIM To analyze the learning curve of RA pedicle screw fixation(PSF)through fitting the operation time curve based on the cumulative summation method.METHODS RA PSFs that were initially completed by two surgeons at the Beijing Jishuitan Hospital from July 2016 to March 2019 were analyzed retrospectively.Based on the cumulative sum of the operation time,the learning curves of the two surgeons were drawn and fit to polynomial curves.The learning curve was divided into the early and late stages according to the shape of the fitted curve.The operation time and screw accuracy were compared between the stages.RESULTS The turning point of the learning curves from Surgeons A and B appeared in the 18th and 17th cases,respectively.The operation time[150(128,188)min vs 120(105,150)min,P=0.002]and the screw accuracy(87.50%vs 96.30%,P=0.026)of RA surgeries performed by Surgeon A were significantly improved after he completed 18 cases.In the case of Surgeon B,the operation time(177.35±28.18 min vs 150.00±34.64 min,P=0.024)was significantly reduced,and the screw accuracy(91.18%vs 96.15%,P=0.475)was slightly improved after the surgeon completed 17 RA surgeries.CONCLUSION After completing 17 to 18 cases of RA PSFs,surgeons can pass the learning phase of RA technology.The operation time is reduced afterward,and the screw accuracy shows a trend of improvement.

Treatment of Anderson Type II Odontoid Fracture in Elderly Patients by Posterior Pedicle Screw Fixation Combined with Iliac Bone Grafting

Objectives: To explore the treatment and related prognosis of elderly patients with Anderson II odontoid fracture with posterior pedicle screw fixation combined with iliac bone grafting. Methods: Retrospective analysis of 17 cases of elderly patients with Anderson II odontoid fracture who underwent posterior pedicle screw fixation combined with iliac bone grafting from January 2013 to December 2016. 17 patients had a history of trauma before surgery, and they all have varying degrees of atlantoaxial instability or subluxation and varying degrees of neck occipital pain and limited mobility. Result: No spinal cord or vertebral artery injury occurred during surgery. Follow-up information is complete. The follow-up period was 6 to 48 months (mean 27.4 ± 12.4 months). Postoperative imaging review prompted a good reduction of cervical spine, stable sequence;no pedicle screw loosening, fracture, iliac bone graft at the location of the situation, odontoid fracture and bone healing at the good, the patient after cervical rotation are limited to varying degrees. Conclusion: Posterior pedicle screw fixation combined with iliac bone grafting in elderly patients with Anderson II odontoid fracture can achieve good stability, and the prognosis is good, but long-term cervical rotation function may be affected to varying degrees.

Evaluation of Percutaneous Pedicle Screw Fixation in Patients with Pyogenic Spondylitis of the Thoracolumbar Spine

Background: Basic principle for the treatment of pyogenic spondylitis (PS) is conservative care, but surgical intervention is often required when conservative treatment may fail. We have experienced many conservative cases of various complications due to long-term bed rest and poor pain control. Recently we have adopted percutaneous pedicle screw (PPS) fixation for the treatment of PS as a minimally invasive spine stabilization (MISt) fusion to reduce such morbidity of the conservative care. Objective: To evaluate the impact of PPS fixation in patients with PS. Study Design: A retrospective analysis of the medical records. Subjects, Methods: We reviewed 54 consecutive patients who underwent treatment in our hospital for PS during 2005-2018 and observed for more than 12 months. Of those we excluded cases showing effectiveness to initial treatment (it was defined fever relief or C-reactive protein (CRP) inversion in 3 weeks of antibiotics) so that this study is a retrospective study in cases showing initial treatment resistance. Finally, this study included 29 cases. Medical records of these 29 cases were reviewed for baseline, organism isolated and its detection rate, the clinical outcome in 12 months (Discharge, Transfer, Death), the period from the first visit to our hospital to fever relief, CRP inversion, ambulation, and Discharge or Transfer. Results: These cases were divided into two groups, the conservative group (C-group): 17 cases, and the PPS group (P-group): 12 cases. There is no statistically significant difference in fever relief (p = 0.051) and CRP inversion (p = 0.208). The period to ambulation and discharge or transfer was significantly shorter in group P (p = 0.020, p = 0.031). 1-Year survival rate was 92% in the P-group, and 71% in the C-group. There is no statistically significant difference (p = 0.354) between the two groups. The rate of Discharge to home and care facility is 58% in P-group, and 47% in C-group. And the rate of Transfer is 34% in P-group, and 35% in C-group. Conclusion: PPS fixation was effective to achieve shortening the period to ambulation and discharge or transfer. But it was not effective in infection control. This suggests that PPS fixation should be aggressively administered to patients who can expect pain relief and early ambulation by PPS fixation in the patient of PS showing resistance to initial treatment.

Unilateral pedicle screw fixation combined with lumbar interbody fusion for the treatment of lumbar degenerative diseases

Objective To explore the feasibility and efficiency of the treatment of lumbar degenerative diseases after transforaminal lumbar interbody fusion (TLIF) and posterolateral fusion (PLF) procedures in which unilateral pedicle screw fixation was used.

Safety factors for anterior pedicle screw fixation tunnel in axis

Objective To investigate feasibility and safety of anterior pedicle screw fixation tunnel in the axis so as to provide theoretic evidence for further clinical application.Methods Thirty-two dry axis specimens were used foranterior

Atlantoaxial pedicle screw fixation for old odontoid fracture combined with atlantoaxial instability

Objective To explore the clinical effect of the trans-atlantoaxial pedicle screw-rod internal fixation and fusion in treatment of old odontoid fracture combined with atlantoaxial instability. Methods The study involved 48 patients with

Free-hand cervical pedicle screw fixation for upper cervical fracture and instability

Objective To evaluate the clinical effect of the free-hand cervical pedicle screw fixation in treatment of the upper cervical fracture and instability. Methods A retrospective review was performed on 15 patients

The application of C1-C2 pedicle screw internal fixation on the upper cervical diseases of children

Objective To report five cases of puerile (【9 years) atlantoaxial instability which underwent C1-C2 pedicle screw internal fixation by posterior approach,and to introduce the surgical technique and the key point

Clinical application of improved 2D computer-assisted fluoroscopic navigation through simulating a 3D vertebrae image to guide pedicle screw internal fixation

Objective To study the effect of using improved 2D computer-assisted fluoroscopic navigation through simulating 3D vertebrae image to guide pedicle screw internal fixation.Methods Posterior pedicle screw internal fixation,distraction

Posterior Selective Thoracic Fusion in Adolescent Idiopathic Scoliosis Patients:a Comparison of All Pedicle Screws versus Hybrid Instrumentation

Objective To analyze the influence of segmental pedicle screws versus hybrid instrumentation on the correction results in adolescent idiopathic scoliosis patients undergoing posterior selective thoracic fusion. Methods By reviewing the medical records and roentgenograms of adolescent idiopathic scoliosis patients who underwent selective thoracic fusion from February 2000 to January 2007 in our hospital, the patients were divided into 2 groups according to different instrumentation fashions： Group A was hook-screw-rod （hybrid） internal fixation type, Group B was screw-rod （all pedicle screws） internal fixation type, and the screws were used in every segment on the concave side of the thoracic curve. The parameters of the scoliosis were measured and the correction results were analyzed. Results Totally, 48 patients （7 males, 41 females） were included, with an average age of 14.4 years old and a mean follow-up time of 12.3 months. Thirty and 18 patients were assigned to group A and group B, respectively. The mean preoperative coronal Cobb angles of the thoracic curve were 48.8° and 47.4°, respectively. After surgery, they were corrected to 13.7° and 6.8°, respectively. At final follow-up, they were 17.0° and 9.5°, with an average correction rate of 64.6% and 79.0%, respectively, and the correction rate of group B was significantly higher than that of group A （P=0.003）. The mean preoperative coronal Cobb angles of the lumbar curve were 32.6° and 35.2°, respectively. After surgery, they were corrected to 8.6° and 8.3°, respectively. At final follow-up, they were 10.3° and 11.1°, with an average correction rate of 66.8% and 69.9%, respectively, and the correction rate of group B was significantly higher than that of group A （P=0.003）. The correction loss of the thoracic curve and lumbar curve in the 2 groups were 3.1° and 1.8°, 2.4° and 2.4°, respectively. No significant difference was noted （both P〉0.05）. The decompensation rate at final follow-up in these 2 groups were 4% （1/25） and 7.1% （1/14） respectively, with no significant difference （P〉0.05）.

Effect of vertebroplasty combined with pedicle internal fixation on senile osteoporotic vertebral compression fracture

Objective:To investigate the effect of vertebroplasty combined with pedicle screw fixation in the treatment of senile osteoporotic vertebral compression fractures.Methods:Eighty-one patients with senile osteoporotic vertebral compression fractures were enrolled in our hospital from January 2015 to January 2019.They were randomly divided into a single group(40 cases)and a combined group(41 cases).),a single group was treated with pedicle screw internal fixation,and the combined group was treated with vertebroplasty.The recovery,pain and dysfunction index of the injured vertebrae before and after operation were compared between the two groups.The serum neurological function related indexes before and after operation were compared and the incidence of postoperative adverse events were recorded.Results:There was no significant difference in the recovery of the injured vertebrae between the two groups(P>0.05).The compression ratio,spinal stenosis rate and Cobb angle of the combined group were significantly lower than the single group(P<0.05).On the 3rd postoperative day,there were no significant differences between the two groups in Visual Analogue Scale/Score(VAS)and Oswestry Dability Index(ODI)scores(P>0.05).The VAS and ODI scores of the group were significantly lower than those of the single group(P<0.05).On the 3rd day after surgery,the neuron-specific enolase(NSE)and brain derived neurotrophic factor(brain-derived neurotrophic factor)were used.The levels of BDNF,S100βand Nerve growth factor(NGF)were not significantly different(P>0.05).At 3 months after operation,the level of BDNF in the combined group was significantly higher than that in the single group.The levels of NSE,S100βand NGF were significantly lower than that of the single group.The group(P<0.05);the incidence of adverse events in the combined group was significantly lower than that in the single group(P<0.05).Conclusions:Vertebroplasty combined with pedicle screw fixation for the treatment of senile osteoporotic vertebral compression fracture can effectively improve the recovery of postoperative vertebral body structure,postoperative pain and dysfunction in Jianing patients,improve postoperative neurological function To reduce the incidence of adverse events,with clinical promotion significance.

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.

Study on clinical effects of pedicle screw combined with immobilized implantation bone by wirerope and hallow compression screw immobilization in treating spondylolysis of lumbar vertebra of multiple segments of adults

Objective:To observe clinical effects of pedicle screw fixation combined with cable wires and bone graft and cannulated compression screws on adult multi-segment lumbar spondylolysis.Methods:70 cases of patients with multi-segment lumbar spondylolysis were selected in our hospital.According to different surgical schemes,these patients were divided into the observation group(35 cases)and the control group(35 cases).The observation group received pedicle screw fixation combined with cable wires and bone graft and the control group received cannulated compression screw fixation.Macnab criteria were adopted to implement a therapeutic evaluation of two groups of patients to make an observation and comparison of the excellent and good rate of surgery and a series of indicators including perioperative clinical effects,intraoperative blood loss,duration of surgery,hospital length of stay(HLOS),visual analogue scale(VAS),Oswestry disability index and Japanese Orthopaedic Association(JOA)score.Results:The excellent and good rate of the observation group was 97.14%,and that of the control group was 82.86%,the difference between two groups was statistically significant(χ^(2)=6.248,p=0.012).The differences in intraoperative blood loss,duration of surgery and HLOS between two groups were statistically significant(t=-4.55,t=-4.55,t=-4.55;p<0.05).Oswestry index,VAS score and JOA score of the observation group were(2.4±0.9),(28.5±6.4)and(27.1±3.1)respectively,and these of the control group were(3.5±1.2),(37.1±7.8)and(21.3±2.7)respectively,the differences between two groups were statistically significant(t=4.338,t=5.043,t=8.347,p<0.05).Conclusions:Pedicle screw combined with immobilized implantation bone by wirerope has an excellent clinical effect on the treatment of adult multi-segment lumbar spondylolysis,and it has a series of advantages such as fast postoperative recovery,small surgical trauma and so on.In addition,this technique can also restore the stability of spinal segments and relieve pains to a greater degree.

Pedicle screw fixation for cervical spine instability： clinical efficacy and safety analysis

Background Reports of applying cervical pedicle screw （CPS） system in the posterior cervical spine surgeries are limited because of its inherent risk of neurovascular injury. The clinical results of cervical spine instability treated with CPS system were retrospectively analyzed, and the clinical efficacy and safety of this management were evaluated. Methods Twenty-five patients with cervical spine instability undergoing posterior C3-C7 single/double door laminoplasty and free-hand CPS fixation as well as graft fusion were investigated; of whom, 3 were due to trauma, and 22 degenerative cervical pathogenesis. One hundred and fifty in total, CPSs were implanted in 5 cervical segments for 1 patient, 4 for 2, 3 for 18, and 2 for 4. Japanese Orthopaedic Association （JOA） score and its improvement rate, neck disability index （NDI）, segmental stability, pedicle cortex perforation rate and other complication-associated parameters were assessed. Results The average follow-up was 16.6 （6-30） months. Compared with pre-operative values, JOA score improved by 4.10±0.84 points on average （P 〈0.05） at 6 months post operation, with a mean improvement rate of 61%. While the pre-operative and 6-month post-operative NDI were 32.96_-＇_-~.13 and 16.84_＋4.40 （P 〈0.05）, respectively. At 6-month post-operation and the final follow-up, fused segments were stable. Pedicle cortex perforation rate was 8.0%, with no neurovascular complications observed. Conclusions Anatomizing the pre-operative radiographic data facilitates the precise operative design prior to surgery; and CPS system is capable of offering safe and satisfying outcomes in the management of cervical spine instability.

斜外侧腰椎椎间融合联合经皮椎弓根钉内固定后前凸角与融合器沉降的关系

背景:随着医疗技术的不断进步,斜外侧腰椎椎间融合联合经皮椎弓根钉内固定已成为治疗腰椎退行性疾病的一种常用方法,然而关于术后不同节段前凸角变化与融合器沉降之间的关系尚缺乏深入研究。目的:探究斜外侧腰椎椎间融合联合经皮椎弓根钉固定后不同节段前凸角变化与融合器沉降的关系。方法:选择2019年2月至2023年4月于潍坊市中医院行斜外侧腰椎椎间融合联合经皮椎弓根钉固定治疗的腰椎退行性疾病患者93例为研究对象,根据术后椎间隙高度丢失值,分为融合器沉降组(25例,≥2 mm)和非融合器沉降组(68例,<2 mm)。采用多因素Logistic回归法分析融合器沉降的危险因素,应用逐步回归法评估各危险因素与融合器沉降的关系,构建风险预测模型并评价。结果与结论:①最终校正混杂因素后,腰椎前凸角丢失值和节段前凸角改善值均与融合器沉降风险仍存在独立相关性(P<0.05);②年龄、Oswestry功能障碍指数、椎间隙高度改善值、节段前凸角改善值以及腰椎前凸角丢失值,均是融合器沉降发生的独立影响因素(P<0.05),其中年龄、腰椎前凸角丢失值、椎间隙高度改善值和节段前凸角改善值与融合器沉降关联最紧密;③多元Logistic回归模型分析结果显示,当P=0.80时,约登指数最高,预测效果最好,准确度为89.27%,灵敏度为86.67%,特异度为89.89%;模型评价结果显示,其区分度较好、准确度较高;④随着腰椎前凸角丢失值和节段前凸角改善值升高,融合器沉降风险增加,影响临床疗效;⑤提示年龄、腰椎前凸角丢失值、椎间隙高度改善值和节段前凸角改善值与融合器沉降关联最紧密,临床医生应多加关注。

微创PSF联合PVP预防骨质疏松性椎体压缩性骨折再骨折的疗效分析

目的探讨微创椎弓根螺钉内固定（PSF）联合经皮椎体成形术（PVP）预防胸腰椎骨质疏松性椎体压缩性骨折（OVCF）再骨折的临床疗效。方法选取2011年7月至2013年5月收治的胸腰椎OVCF且无合并神经症状的患者56例，随机分为对照组（n=29例）和观察组（n=27例）。对照组只行双侧PVP，观察组行PSF联合PVP，比较两组手术时间、骨水泥注入量、骨水泥分布和外漏情况。术前术后疼痛视觉模拟评分（VAS），测量患者术后x线片矢状面Cobb角和椎体高度恢复情况。结果对照组骨水泥注入量（5．1±1．2）ml．手术时间（31．2±3．8）min；观察组骨水泥注入量（5．4±1．4）ml，手术时间（65．7±5．3）min。所有病例随访2年，观察组术后14d、30d、2个月、6个月、1年、2年VAS评分显著低于对照组（P〈0．05）；观察组术后Cobb’s角显著低于对照组（P〈0．05）；观察组术后各时点椎体高度恢复率显著高于对照组（P〈0．05）。结论微创PSF联合pvp可以有效预防OVCF再骨折的发生。

改道重新置入椎弓根螺钉的有限元分析与生物力学验证

背景:目前,椎弓根螺钉固定技术被公认为腰椎后路融合的金标准,然而,该技术也存在一些负面并发症,例如置钉方向不理想、螺钉松动、断裂等。针对这一问题,有必要对螺钉重新置钉的力学特性进行深入研究,优化置钉方案提高手术的成功率和安全性。目的:通过结合有限元分析和生物力学实验验证,对传统轨迹椎弓根螺钉在多次拔出过程中的力学性能进行对比分析,以揭示螺钉在多次拔出过程中拔出强度的变化规律,为临床提供关于椎弓根螺钉重新置钉的安全性和有效性方面的科学依据。方法:基于CT扫描数据三维重建L4腰椎模型,利用3D打印技术打印生物实验样本,并按照置钉方案进行拔出实验。根据CT数据和标准椎弓根螺钉参数,建立L4腰椎有限元模型和椎弓根螺钉模型(直径为6.0 mm,长度为45 mm),根据置钉角度和次数将模型分为5种工况,建立有限元模型来模拟轴向拔出力实验,通过观察椎体的应力分布以及螺钉的轴向最大拔出强度,将3D打印力学实验结果与仿真结果进行对比分析。结果与结论:①设计并搭建了一套椎弓根螺钉拔出实验装置;②3D打印力学实验中对比正常置钉和一次不理想置钉工况下的4组模型,正常置钉组模型展示了最大抗拔出力,为(1422.63±23.80)N,且随着置钉偏移角度的增大,各组模型的最大抗拔出力逐渐减小;③对比一次不理想置钉和修正置钉工况,当不理想置钉偏移角度大于3号模型的角度时,重新以正常角度置钉有助于提升螺钉的抗拔出力;④对比二次不理想置钉和再次修正置钉工况,重新以正常角度置钉工况降低了螺钉的抗拔出力,不更换螺钉情况下不建议进行第3次置钉;⑤3D打印力学实验得出的拔出强度与有限元模拟得出的拔出强度具有较高的相关性,相关系数为0.98,两种方法的结果无显著差异(P>0.05)。