Effect of fractures on mechanical behavior of sand powder 3D printing rock analogue under triaxial compression

In practical engineering applications,rock mass are often found to be subjected to a triaxial stress state.Concurrently,defects like joints and fractures have a notable impact on the mechanical behavior of rock mass.Such defects are identified as crucial contributors to the failure and instability of the surrounding rock,subsequently impacting the engineering stability.The study aimed to investigate the impact of fracture geometry and confining pressure on the deformation,failure characteristics,and strength of specimens using sand powder 3D printing technology and conventional triaxial compression tests.The results indicate that the number of fractures present considerably influences the peak strength,axial peak strain and elastic modulus of the specimens.Confining pressure is an important factor affecting the failure pattern of the specimen,under which the specimen is more prone to shear failure,but the initiation,expansion and penetration processes of secondary cracks in different fracture specimens are different.This study confirmed the feasibility of using sand powder 3D printing specimens as soft rock analogs for triaxial compression research.The insights from this research are deemed essential for a deeper understanding of the mechanical behavior of fractured surrounding rocks when under triaxial stress state.

Factors influencing further vertebral height loss following percutaneous vertebroplasty in osteoporotic vertebral compression fractures:A 1-year follow-up study

BACKGROUND Osteoporotic vertebral compression fractures(OVCFs)contribute to back pain and functional limitations in older individuals,with percutaneous vertebroplasty(PVP)emerging as a minimally invasive treatment.However,further height loss post-PVP prompts investigation into contributing factors.AIM To investigate the factors associated with further height loss following PVP with cement augmentation in OVCF patients.METHODS A total of 200 OVCF patients who underwent successful PVP between January 2021 and December 2022 were included in this study.“Further height loss”during 1 year of follow-up in OVCF patients with bone edema was defined as a vertical height loss of≥4 mm.The study population was divided into two groups for analysis:The“No Further Height Loss group(n=179)”and the“Further Height Loss group(n=21).”RESULTS In comparing two distinct groups of patients,significant differences existed in bone mineral density(BMD),vertebral compression degree,prevalence of intravertebral cleft(IVF),type of bone cement used,and cement distribution patterns.Results from binary univariate regression analysis revealed that lower BMD,the presence of IVF,cleft distribution of bone cement,and higher vertebral compression degree were all significantly associated with further height loss.Notably,the use of mineralized collagen modified-poly(methyl methacrylate)bone cement was associated with a significant reduction in the risk of further height loss.In multivariate regression analysis,lower BMD and the presence of IVF remained significantly associated with further height loss.CONCLUSION Further height loss following PVP in OVCF patients is influenced by a complex interplay of factors,especially lower BMD and the presence of IVF.These findings underscore the importance of assessing and managing these factors when addressing height loss following PVP in OVCF patients.

Macro-meso fracture evolution mechanism of hollow cylindrical granite with different hole diameters under conventional triaxial compression

In order to study and analyze the stability of engineering rock mass under non-uniform triaxial stress and obtain the evolution mechanism of the whole process of fracture,a series of conventional triaxial compression tests and three-dimensional numerical simulation tests were carried out on hollow granite specimens with different diameters.The bearing capacity of hollow cylindrical specimen is analyzed based on elasticity.The results show that:1)Under low confining pressure,the tensile strain near the hole of the hollow cylindrical specimen is obvious,and the specimen deformation near the hole is significant.At the initial stage of loading,the compressive stress and compressive strain of the specimen are widely distributed.With the progress of loading,the number of microelements subjected to tensile strain gradually increases,and even spreads throughout the specimen;2)Under conventional triaxial compression,the cracking position of hollow cylinder specimens is concentrated in the upper and lower parts,and the final fracture mode is generally compressive shear failure.The final fracture mode of complete specimen is generally tensile fracture.Under high confining pressure,the tensile cracks of the sample are concentrated in the upper and lower parts and are not connected,while the cracks of the upper and lower parts of the intact sample will expand and connect to form a fracture surface;3)In addition,the tensile crack widths of intact and hollow cylindrical specimens under low confining pressure are larger than those under high confining pressure.

Graph theoretical analysis of limestone fracture network damage patterns based on uniaxial compression test

The topological attributes of fracture networks in limestone,subject to intense hydrodynamics and intricate geological discontinuities,substantially influence the mechanical and hydraulic characteristics of the rock mass.The dynamical evolution of fracture networks under stress is crucial for unveiling the interaction patterns among fractures.However,existing models are undirected graphs focused on stationary topology,which need optimization to depict fractures'dynamic development and rupture process.To compensate for the time and destruction terms,we propose the damage network model,which defines the physical interpretation of fractures through the ternary motif.We focus primarily on the evolution of node types,topological attributes,and motifs of the fracture network in limestone under uniaxial stress.Observations expose the varying behavior of the nodes'self-dynamics and neighbors'adjacent dynamics in the fracture network.This approach elucidates the impact of micro-crack behaviors on large brittle shear fractures from a topological perspective and further subdivides the progressive failure stage into four distinct phases(isolated crack growth phase,crack splay phase,damage coalescence phase,and mechanical failure phase)based on the significance profile of the motif.Regression analysis reveals a positive linear and negative power correlation between fracture network density and branch number to the rock damage resistance,respectively.The damage network model introduces a novel methodology for depicting the interaction of two-dimensional(2D)projected fractures,considering the dynamic spatiotemporal development characteristics and fracture geometric variation.It helps dynamically characterize properties such as connectivity,permeability,and damage factors while comprehensively assessing damage in rock mass fracture networks.

Experimental Study on the Repair Effect of Xianlinggubao Capsule on Osteoporotic Vertebral Compression Fracture in Rabbits

[Objectives]To observe the effect of Xianlinggubao Capsule on osteoporotic vertebral compression fracture(OVCF)in rabbits and the influence mechanism of the repair of fractures.[Methods]Female June age 30 rabbits were randomly divided into control group,model control group and Xianlinggubao group.After bilateral ovariectomy,the model control group and Xianlinggubao group were injected with dexamethasone continuously for 4 weeks,and then the OVCF compound model was established by surgery.The Xianlinggubao group was treated with Xianlinggubao at a dose of 300 mg/(kg·d)for 60 d,while the blank control group and the model control group were treated with the same amount of normal saline for 60 d.The number of blood vessels and the expression of bone morphogenetic protein-2(BMP-2)were detected by immunohistochemical staining and the bone mineral density(BMD)in the callus of the third lumbar fracture area of rabbits was measured.The content of serum phosphorus(P),alkaline phosphatase(ALP)and total calcium(TCa)in rabbit venous blood were measured by automatic biochemical analyzer.The content of vascular endothelial growth factor(VEGF)and platelet-derived growth factor(PDGF)in rabbit venous blood were measured by ELISA kit.[Results]The number of blood vessels and the expression of BMP-2 in the callus of the third lumbar fracture area of rabbits was high in Xianlinggubao group,the content of serum P,ALP,TCa,VEGF and PDGF was obviously increased,BMD was obviously increased,the bone microstructure of the third lumbar vertebrae fracture area of rabbits was basically restored.Compared with the model control group(P<0.05),the difference was statistically significant.[Conclusions]Xianlinggubao Capsule can increase calcium and phosphorus deposition,promote the formation of blood vessels in the fracture area of OVCF in rabbits,and have a strong repair effect on OVCF in rabbits.

Fracture evolution around pre-existing cylindrical cavities in brittle rocks under uniaxial compression

The development of fracture around pre-existing cylindrical cavities in brittle rocks was examined using physical models and acoustic emission technique. The experimental results indicate that when granite blocks containing one pre-existing cylindrical cavity are loaded in uniaxial compression condition, the profiles of cracks around the cavity can be characterized by tensile cracking （splitting parallel to the axial compression direction） at the roof-floor, compressive crack at two side walls, and remote or secondary cracks at the perimeter of the cavity. Moreover, fracture around cavity is size-dependent. In granite blocks containing pre-existing half-length cylindrical cavities, compressive stress concentration is found to initiate at the two sidewalls and induce shear crack propagation and coalescence. In granite blocks containing multiple parallel cylindrical cavities, the adjacent cylindrical cavities can influence each other and the eventual failure mode is determined by the interaction of tensile, compressive and shear stresses. Experimental results show that both tensile and compressive stresses play an important role in fracture evolution process around cavities in brittle rocks.

Fracture features of brittle coal under uniaxial and cyclic compression loads

Under the efects of complex geological and stress environments,burst hazards continue to be a major challenge for underground space utilization and deep resources exploration as its occurrence can lead to personnel causalities,equipment damage and structural collapse.Considering the stress path experienced by in-situ coal body,cyclic loading appears in quite various forms for instance shearer cutting,overlying strata breakage,hydro-fracturing and blasting,during tunnel,mining and underground space utilizing process.The stability of the underground coal body subject to periodic loading/unloading stress is extremely important for maintain the function of designed engineering structure for waste storage,safe mining,roadway development,gas recovery,carbon sequestration and so on.The mechanical properties of hard rock subject to cyclic fatigue loads has been intensively investigated by many researchers as the rock burst induced by supercritical loads has long been a safety risk and engineering problems for civil and tunneling engineering under deep overburden.More recently,the mechanical properties of coal samples under cyclic fatigue loads is investigated from the aspect of hysteresis,energy dissipation and irreversible damage as the burst hazards of brittle coal is rising in many countries.However,the crack propagation and fracture pattern of brittle coal need more research to understand the micro mechanism of burst incubation subject to cyclic fatigue loads as brittle coal can store more elastic strain energy and rapidly release the energy when its ultimate strength once reached.This research studied the internal crack status corresponding to diferent cyclic fatigue loading stage of brittle coal samples.The AE monitoring was applied during the uniaxial and cyclic loading process of brittle coal samples to record the crack intensity of samples at diferent loading stages.The damage evolution curve corresponding to loading status was then determined.The fracture pattern of coal samples determined by micro-CT scan was observed and discussed.It has been found by this paper that brittle coal of uniaxial compression tests demonstrated sudden failure caused by major splitting fracture while that of cyclic fatigue tests experienced progressive failure with mixture fracture network.

The impact of endplate fracture on postoperative vertebral height loss and kyphotic deformity during treatment of osteoporotic vertebral compression fractures with balloon kyphoplasty

This retrospective study investigated the impact of endplate fracture on postoperative vertebral height loss and kyphotic deformity in 144 patients with osteoporotic vertebral compression fracture （OVCF）, who received balloon kyphoplasty. Patients were divided into four groups： Group 1 had no superior endplate fracture, Group 2 had fractures on the anterior portion of the superior endplate, Group 3 had fractures on the posterior portion of the superior endplate, and Group 4 had complete superior endplate fractures. Anterior and middle vertebral body height, vertebral compression ratio, vertebral height loss rate, and kyphosis Cobb angle of each patient were measured and visual analogue scale （VAS） and Oswestry disability index （ODI） scores were recorded. The anterior vertebral height and kyphosis deformity of all groups significantly improved after the surgery, whereas substantial anterior vertebral height loss and increased Cobb angle were observed in all patients at the last follow-up. Although the vertebral height loss rate and the Cobb angle in Group 2, 3 and 4 were larger compared with Group 1 at the last follow-up, only the vertebral height loss rate in Group 4 and the increase in the Cobb angle in Group 2 and 4 were statistically different from those in Group 1. The VAS and ODI scores in all groups measured after the surgery and at the last follow-up were significantly lower compared with preoperative scores, but there was no significant difference among these groups. Balloon kyphoplasty significantly improved vertebral fracture height and kyphosis. Vertebral height loss and increased kyphotic deformity were observed in OVCF patients with endplate fractures after the surgery. Postoperative aggravation of kyphosis was observed in Group 2. Furthermore, severe vertebral height loss and increased kyphotic deformity were confirmed in Group 4 after the surgery. Our results suggested that postoperative vertebral height loss and aggravation of kyphosis may be associated with biomechanical changes in the vertebral body caused by endplate fracture. Therefore, surgery should not only restore compressed vertebral body height and correct kyphosis, but also correct the deformity of endplate to achieve an effective treatment of OVCF patients with endplate fracture.

Managements of osteoporotic vertebral compression fractures:A narrative review

Osteoporotic vertebral compression fractures(OVCFs)are the most common fragility fracture and significantly influence the quality of life in the elderly.Currently,the literature lacks a comprehensive narrative review of the management of OVCFs.The purpose of this study is to review background information,diagnosis,and surgical and non-surgical management of the OVCFs.A comprehensive search of PubMed and Google Scholar for articles in the English language between 1980 and 2021 was performed.Combinations of the following terms were used:compression fractures,vertebral compression fractures,osteoporosis,osteoporotic compression fractures,vertebroplasty,kyphoplasty,bisphosphonates,calcitonin,and osteoporosis treatments.Additional articles were also included by examining the reference list of articles found in the search.OVCFs,especially those that occur over long periods,can be asymptomatic.Symptoms of acute OVCFs include pain localized to the mid-line spine,a loss in height,and decreased mobility.The primary treatment regimens are pain control,medication management,vertebral augmentation,and anterior or posterior decompression and reconstructions.Pain control can be achieved with acetaminophen or nonsteroidal anti-inflammatory drugs for mild pain or opioids and/or calcitonin for moderate to severe pain.Bisphosphonates and denosumab are the first-line treatments for osteoporosis.Vertebroplasty and kyphoplasty are reserved for patients who have not found symptomatic relief through conservative methods and are effective in achieving pain relief.Vertebroplasty is less technical and cheaper than kyphoplasty but could have more complications.Calcium and vitamin D supplementation can have a protective and therapeutic effect.Management of OVCFs must be combined with multiple approaches.Appropriate exercises and activity modification are important in fracture prevention.Medication with different mechanisms of action is a critical long-term causal treatment strategy.The minimally invasive surgical interventions such as vertebroplasty and kyphoplasty are reserved for patients not responsive to conservative therapy and are recognized as efficient stopgap treatment methods.Posterior decompression and fixation or Anterior decompression and reconstruction may be required if neurological deficits are present.The detailed pathogenesis and related targeted treatment options still need to be developed for better clinical outcomes.

Effect of Relative Stress on Post-Peak Uniaxial Compression Fracture Energy of Concrete

Fracture energy in strain softening regime was investigated analytically by considering microstructures interaction and interplay.Based on gradient-dependent plasticity, the thickness of localized band was determined completely and strictly by characteristic length in relation to average grain diameter.After obtaining the plastic shear displacement of the band,the formula on axial response of concrete was proposed and the analytical post-peak fracture energy was deduced.A comparison between present theoretical results and earlier experimental results was carried out and the analytical result is reasonable and has a plausible foundation as considering the localized failure theoretically.Decreasing the relative stress leads to increasing the fracture energy non-linearly.The larger the shear elastic modulus and shear softening modulus,the lower the post-peak fracture energy.A larger fracture energy is caused by a larger thickness of shear band or a larger characteristic length of concrete material.If the inclination angle of the shear band and the compressive strength are not concerned with structural size of specimen,the post-peak fracture energy is size independent.

A Comparative Study of High-viscosity Cement Percutaneous Vertebroplasty vs. Low-viscosity Cement Percutaneous Kyphoplasty for Treatment of Osteoporotic Vertebral Compression Fractures

The clinical effects of two different methods–high-viscosity cement percutaneous vertebroplasty（PVP） and low-viscosity cement percutaneous kyphoplasty（PKP） in the treatment of osteoporotic vertebral compression fractures（OVCFs） were investigated. From June 2010 to August 2013, 98 cases of OVCFs were included in our study. Forty-six patients underwent high-viscosity PVP and 52 patients underwent low-viscosity PKP. The occurrence of cement leakage was observed. Pain relief and functional activity were evaluated using the Visual Analog Scale（VAS） and Oswestry Disability Index（ODI）, respectively. Restoration of the vertebral body height and angle of kyphosis were assessed by comparing preoperative and postoperative measurements of the anterior heights, middle heights and the kyphotic angle of the fractured vertebra. Nine out of the 54 vertebra bodies and 11 out of the 60 vertebra bodies were observed to have cement leakage in the high-viscosity PVP and low-viscosity PKP groups, respectively. The rate of cement leakage, correction of anterior vertebral height and kyphotic angles showed no significant differences between the two groups（P〉0.05）. Low-viscosity PKP had significant advantage in terms of the restoration of middle vertebral height as compared with the high-viscosity PVP（P〈0.05）. Both groups showed significant improvements in pain relief and functional capacity status after surgery（P〈0.05）. It was concluded that high-viscosity PVP and low-viscosity PKP have similar clinical effects in terms of the rate of cement leakage, restoration of the anterior vertebral body height, changes of kyphotic angles, functional activity, and pain relief. Low-viscosity PKP is better than high-viscosity PVP in restoring the height of the middle vertebra.

Locking compression plate+T-type steel plate for postoperative weight bearing and functional recovery in complex tibial plateau fractures

Complex tibial plateau fractures can seriously affect quality of life and physical and mental health of patients.The anatomical relationship between the proximal tibial bone and soft tissue is complex,resulting in different types of tibial plateau fractures.Violent trauma can lead to displaced fracture,serious soft tissue injury,and potentially,dislocation of the knee joint.Therefore,tibial plateau fractures are extremely unstable.AIM To assess the use of locking compression plate(LCP)+T-type steel plate for postoperative weight bearing and functional recovery of complex tibial plateau fractures.METHODS Ninety-seven patients with complex tibial plateau fractures who underwent surgery at our hospital were selected for retrospective study.Forty-nine patients had been treated with LCP+T-type steel plate limited internal fixation(study group),and 48 patients with bilateral ordinary steel plate support(control group).The operation process index,postoperative rehabilitation related index,Rasmussen score of the knee joint,tibial plateau varus angle(TPA),tibial plateau retroversion angle(PA),and surgical complications of the two groups were compared.RESULTS The operation time and intraoperative bone graft volume in the study group were lower than those in the control group(P<0.05).There were no significant differences in surgical bleeding,anterior external incision length,postoperative drainage,hospital stay duration,and fracture healing time between the groups(P>0.05).There was no significant difference in the TPA and PA angle between the groups immediately and 18 mo after surgery(P>0.05).At 12 mo after surgery,the Rasmussen scale score was higher in the study group than in the control group(P<0.05).There was no significant difference in the Rasmussen scale score at 18 mo after surgery,and the radiology score at 12 and 18 mo after surgery,between the two groups(P>0.05).The postoperative complication rate in the study group(3.77%)was lower than that in the control group(15.09%;P<0.05).CONCLUSION LCP+T-type steel plate internal fixation has advantages in terms of minimizing trauma and enabling early postoperative functional exercise,promoting functional recovery and lower limb weight-bearing,and reducing postoperative complications.

Mode II fracture analysis of double edge cracked circular disk subjected to different diametral compression

A detailed analysis of mode II stress intensity factors(SIFs) for the double edge cracked Brazilian disk subjected to different diametral compression is presented using a weight function method. The mode II SIFs at crack tips can be obtained by simply calculating an integral of the product of mode II weight function and the shear stress on the prospective crack faces of uncracked disk loaded by a diametral compression. A semi-analytical formula for the calculation of normalized mode II SIF, f _Ⅱ, is derived for different crack lengths (from 0.1 to 0.7) and inclination angles (from 10° to 75°) with respect to loading direction. Comparison between the obtained results and finite element method solutions shows that the weight function method is of high precision. Combined with the authors previous work on mode I fracture analysis, the new specimen geometry can be used to study fracture through any combination of mode I and mode II loading by a simple alignment of the crack relative to the diameter of compression loading, and to obtain pure mode II crack extension. Another advantage of this specimen geometry is that it is available directly from rock core and is also easy to fabricate.

Outcomes of different minimally invasive surgical treatments for vertebral compression fractures:An observational study

BACKGROUND Osteoporosis with vertebral compression fractures is increasingly common in the elderly population.Cement augmentation is one of the effective surgical treatments for these patients.Currently,there are several different types of cement augmentation treatments.No studies have compared the safety and efficacy of different cement augmentation types for the treatment of such fractures;thus,we retrospectively compared vertebroplasty,balloon kyphoplasty,and kyphoplasty with SpineJack or an intravertebral expandable pillar.AIM To compare the postoperative safety and efficacy of each surgical intervention in treating vertebral compression fractures.METHODS We retrospectively analyzed 354 patients with acute vertebral compression fractures,defined as signal changes in the T1 weighted magnetic resonance imaging,and randomly divided the patients into five groups.Their visual analog scale scores for pain,kyphotic angle,average body height,rate of cement leakage,and occurrence of adjacent vertebral compression fractures were followed for 1 year.One-way analysis of variance,the post hoc Bonferroni test,and Fisher exact probability test were used for statistical analyses.RESULTS All pain scores significantly improved 12 mo postoperatively;however,there was no significant difference between the groups(P=0.325).Kyphoplasty with SpineJack significantly reduced the kyphotic angle(P=0.028)and restored the height of the vertebral body(P=0.02).The rate of adjacent compression fractures was the highest in the vertebroplasty group,with a statistically significant difference according to the Fisher exact probability test(P=0.02).The treatment with the lowest cement leakage rate cannot be identified because of the small sample size;however,kyphoplasty with SpineJack,an IVEP,and vesselplasty resulted in lower rates of cement leakage than balloon kyphoplasty and vertebroplasty.CONCLUSION Kyphoplasty with SpineJack has good outcomes in kyphotic angle reduction and body height restoration.Vertebroplasty has the highest cement leakage rate and adjacent compression fracture occurrence.

Dynamic ModeⅡfracture behavior of rocks under hydrostatic pressure using the short core in compression(SCC)method

The shear failure of rocks under both a static triaxial stress and a dynamic disturbance is common in deep underground engineering and it is therefore essential for the design of underground engineering to quantitively estimate the dynamic ModeⅡfracture toughness KⅡCof rocks under a triaxial stress state.However,the method for determining the dynamic KⅡCof rocks under a triaxial stress has not been developed yet.With an optimal sample preparation,the short core in compression(SCC)method was designed and verified in this study to measure the dynamic KⅡCof Fangshan marble(FM)subjected to different hydrostatic pressures through a triaxial dynamic testing system.The formula for calculating the dynamic KⅡCof the rock SCC specimen under hydrostatic pressures was obtained by using the finite element method in combination with secondary cracks.The experimental results indicate that the failure mode of the rock SCC specimen under a hydrostatic pressure is the shear fracture and the KⅡCof FM increases as the loading rate.In addition,at a given loading rate the dynamic rock KⅡCis barely affected by hydrostatic pressures.Another important observation is that the dynamic fracture energy of FM enhances with loading rates and hydrostatic pressures.

Effect of Auricular Piont Pressing Combined with Thunder-Fire Moxibustion on Abdominal Distension and Constipation After Thoracic Compression Fracture

Objective:To explore the effect of auricular point pressing combined with thunder-fire moxibustion in the treatment of abdominal distension and constipation after thoracic compression fracture.Methods:Totally 100 patients were randomly divided into 4 groups,the observation group 1(n=25)which were treated with conventional nursing combined with auricular piont pressing,observation group 2(n=25)treated with conventional nursing combined with thunder-fire moxibustion,observation group 3(n=25)treated with conventional nursing combined with auricular point pressing and thunder-fire moxibustion,and the control group(n=25)which adopted conventional nursing.First exhaust and defecation time after fracture in 4 groups were observed and compared.Results:The effect of observation group 3 was better than that of observation group 2,observation group 1 and control group(P<0.05).Conclusion:It is obvious that auricular point pressing combined with thunder-fire moxibustion has better result in treating abdominal distension and constipation after thoracic compression fracture.

Full-endoscopic spine surgery treatment of lumbar foraminal stenosis after osteoporotic vertebral compression fractures:A case report

BACKGROUND Few reports have described lumbar foraminal stenosis-induced radiculopathy after treatment by full-endoscopic spine surgery(FESS)combined with percutaneous vertebroplasty(PVP)in patients with vertebral compression fractures.We herein report such a case,including the patient’s treatment process and doctor’s surgical experience.CASE SUMMARY A 79-year-old man presented with symptoms of radiculopathy after sustaining L4 vertebral compression fractures.Imaging and physical examination revealed L4 vertebral compression fractures combined with L3/4 Lumbar foraminal stenosis(LFS).The patient’s symptoms were low back pain with pain in the lateral left leg.Although many reports have described radiculopathy induced by osteoporotic vertebral compression fractures,the use of FESS combined with PVP has rarely been reported.This case report indicates that the combination of FESS and PVP is a safe and effective approach for the treatment of LFS-induced radiculopathy after vertebral compression fractures.This minimally invasive technique has great potential to replace traditional lumbar fixation and decompression surgery.Thus,we suggest the continued accumulation of similar cases to discuss the wider application of FESS.CONCLUSION For patients with osteoporotic vertebral compression fracture(OVCF)and LFS,PVP and FESS can be used to restore the vertebral height and reduce the pressure around the intervertebral foramen.Additionally,the combination of FESS and PVP can treat the pain or numbness of the low back and lower limbs and allow for recovery in a short time with excellent postoperative effects.In general,FESS is a good treatment for radiculopathy caused by foraminal stenosis after OVCF.

A combination of digital design and three-dimensional printing to assist treatment of thoracolumbar compression fractures using percutaneous kyphoplasty

Objective:To evaluate the clinical efficacy of the preoperative digita1 design combined with three dimensional(3D)printing models to assist percutaneous kyphoplasty(PKP)treatment for thoracolumbar compression frac tures.Methods:From January 2018 to August 2020,we obtained data of 99 patients diagnosed thoracolumbar compression fractures.These patients were divided into control group(n=50)underwent traditional PKP surgery,and observation group(n=49)underwent preoperative digital design combined with 3D printing model assisted PKP treatment.The clinical efficacy was evaluated with five parameters,including operation time,number of intraoperative radiographs,visual analogue scale(VAS)score,Cobb Angle change,and high compression rate of injured vertebrae.Results:There were statistically significant differences of operation time and number of intraoperative radio graphs between the two groups(P<0.05).For VAS score,Cobb Angle change and vertebral height compression rate,all of these three parameters were significantly improved when the patients accepted surgery teatment in two groups(P<0.05).However,there were no significant differences between control group and observation group for these three parameters either before or after surgery(P>0.05).Conclusions:Through the design of preoperative surgical guide plate and the application of 3D printing model to guide the operation,the precise design of preoperative surgical puncture site and puncture Angle of the injured vertebra was realized,the number of intraoperative radiographs was reduced,the operation time was shortened and the operation efficiency was improved.

Diagnosis and Treatment and Infection Protection Strategy of Osteoporotic Vertebral Compression Fractures Minimally Invasive Percutaneous Kyphoplasty Surgery during the Prevention and Control of COVID-19

Background: As the global novel coronavirus pneumonia (NCP) remains severe, elderly people are at high risk for NCP and osteoporotic vertebral compression fractures, with high complications and mortality. How to treat patients and protect medical staff from infection, and at the same time strictly prevent the occurrence of clustered transmission events in the hospital, the establishment of perfect pre-hospital emergency measures and infection prevention and control strategy is the first element to ensure success. Objective: To establish the diagnosis and treatment and infection protection strategy for Osteoporotic vertebral compression fractures (OVCF) patients undergoing minimally invasive percutaneous kyphoplasty (PKP) surgery during the prevention and control of COVID-19, so as to ensure the stable, orderly and safe medical treatment. Methods: A total of 583 OVCF patients were admitted to the First Affiliated Hospital of Hebei North University during the epidemic prevention and control period from January 2020 to July 2022. After urgent and outpatient strict standardized screening, 382 patients met the inclusion criteria, including 112 males and 270 females, aged (70.50 ± 5.49) years. The preoperative visual analogue scale (VAS) score was 6.92 ± 1.86. Preoperative Oswestry disability index (ODI) was 74.67 ± 4.84. The satisfaction rate was (45.89 ± 3.67) %. According to the clinical diagnostic criteria and classification, 367 patients were diagnosed as ordinary OVCF, including 156 cases of mild compression and 226 cases of moderate compression. The clinical classification of 15 patients with OVCF diagnosed as COVID-19 was type I, including 10 cases of mild COVID-19 and 5 cases of common COVID-19. All patients were treated with PKP. Results: All patients were followed up at 1 day, 1 month and 3 months after operation, VAS (2.01 ± 0.56, 0.45 ± 0.11, 0 ± 0), ODI (45.41 ± 4.15, 10.22 ± 2.73, 4.03 ± 1.57) and satisfaction (90.12%, 95.57%, 99.23%) were significantly improved compared with those before operation (p < 0.05), and the original medical diseases were not aggravated. In this group, 15 cases of OVCF diagnosed with COVID-19 were given priority to treat COVID-19 under strict three-level protection in the designated isolation ward. PKP was carried out after the condition was stable, and the areas, items and personnel in contact with patients during the perioperative period must be strictly and thoroughly disinfected. The patient had a good prognosis, no complications, no cross-infection in the hospital, and no infection rate among medical staff. Conclusions: The implementation of the diagnosis and treatment and infection protection strategy for OVCF patients undergoing minimally invasive PKP surgery during the prevention and control of COVID-19 has a guiding role in preventing the spread of infection, improving the cure rate, promoting rapid recovery, reducing complications and reducing mortality.

Ankle Arthrodesis Nail Combined with Locking Compression Plate to Stabilize Two-Level Pathologic Tibial Fractures

Treatment of fragility fractures of the distal tibia in the elderly is demanding because of osteopenic bone quality, the delicate soft tissue cuff and frequent critical circulation. We report the case of two-level tibial pseudarthroses in an 83- year-old woman caused by multiple myeloma successfully stabilized by a long ankle arthrodesis nail combined with locking compression plate osteosynthesis. This case is unique, as to our best knowledge, herein diaphyseal fractures were treated for the first time using a technique reported hitherto primarily for fragility ankle and pilon fractures.