Fracture of Limbs Bones in a Town in Post Conflict (Case of Bukavu Town)

Background: Rapid urbanization and increasing fleet in low-income countries are the basis of the higher rate of trauma and fractures. In a post conflict environment, the abnormal movement of firearms and poverty from them may change the configuration’s epidemiological, anatomical and clinical fractures of the limbs bones as well as their care. Goal: To make an inventory on the fractures of the limb bones in Bukavu town, a town in post armed conflict. Method: This work is transversal, retrospective and descriptive on 500 fractures of the limbs bones recorded on a period of 3 months from 1st June to 31st August 2013. Twenty investigators went around different places of Bukavu town to interview and complete a research protocol ad hoc. In total, we recorded 500 subjects with 570 fractures of the limb bones. Results: The average age is 29.4 years old and 37% are male fractured. The main circumstances of occurrence of the fracture of the limbs bones are the falls (31.7%), firearms (22.2%) followed closely by road traffic accidents (21.9%). Students (38.6%) and the unemployed (29.4%) are most victims’ fractures of limb bones. The forearm bones (31.7%) and leg bones (27.2%) are most concerned, 52.2% fractured turned to modern medicine against 41.8% for traditional medicine. Conclusion: The fractures of the limbs bones in Bukavu mainly concern young male subjects. They occur with the waning of a fall and preferentially affect the bones of the forearm. Good governance would reduce the incidence of fractures of the limbs bones and their assessment.

Open Fractures of Limbs by the Bite of Domestic Donkeys: An Unusual Aetiology

Introduction: The aim of this study is to describe the epidemiological, lesional, therapeutic and evolutionary profile of open fractures of limbs by bites of domestic donkeys. Patients and Methods: This is a prospective descriptive study over 28 months made in the Orthopedics-Traumatology department of the Tambacounda Regional Hospital in Senegal, concerning patients bitten by donkeys, resulting in an open fracture of the thoracic and pelvic limbs. Results: Twelve male patients were included. The average age was 10.50 years ± 2.60. The most common circumstance was the bite when two donkeys were separated. The thoracic limbs were the most affected by the occurrence of the arm. Cauchoix-Duparc type II and AO A2 and B2 were predominant. The essential trimming/osteosynthesis was carried out within 24 hours of the bite. Serovaccination was systematic, but on the other hand, a single dose of anti-rabies serum was administered. Pinning was the most commonly used bone synthesis. Complications were mainly infectious, followed by a case of radial nerve palsy and non-union on pins. Conclusion: The typical profile of an open donkey bite fracture is a male child/adolescent who is bitten during the separation of two fighting donkeys. The lesions are most often found in the thoracic limbs with a predominance of Cauchoix-Duparc type II and type A2 and B2 fractures of the AO, whose treatment consisted of trimming and pinning. The infectious complications of the soft tissues marked the evolution.

Epidemiological and Clinical Pattern of Open Fractures of Long Bones of the Lower Limbs in the South-West Region of Cameroon: A 5-Year Review

Background: An open fracture is an injury in which the fracture site and/or hematoma communicates with the external environment. It is associated with significant morbidity and disability and is a challenge to the surgical team. The lower extremities are the most often exposed to traumatic injuries compared to other anatomical parts of the body. Patterns of open fractures differ with different mechanisms of injury and the segment of the long bone affected. The correct and timely management of open fractures is beneficial to the patients and leads to a more favorable outcome. This study aimed at describing the pattern of open fractures of long bones of the lower limb treated in 3 major hospitals of the south west region, Cameroon. Methodology: This was a hospital-based retrospective review of files of patients with open fractures of long bones of the lower limb managed at the surgical units of three secondary health facilities in the South-West region of Cameroon from the 1st of January 2015 to the 31st of December 2019. The socio-demographic characteristics, clinical presentation, treatment modalities, and outcomes were recorded. The data was stored and analyzed using Epi info version 7.0 and SPSS version 23.0 respectively. Results: A total of 195 files of patients aged 8 to 80 years were studied. The main age group affected was between 20 - 40 years. There were 147 (75.4%) males and 48 (24.6%) females giving a sex-ratio of 3.1:1. The most common cause was road traffic crashes 142 (72.8%). In 98 cases (50.3%), the left side was more involved. The tibia was the most common long bone affected in 75 (38.5%) cases. Comminuted fracture was the most common fracture pattern encountered in 126 cases (64.6%). A total of 76 (39%) fractures were graded Gustilo-Anderson IIIA. External fixator was used in 112 cases (57.1%) and internal fixator in 86 cases (42.9%). We recorded 127 (65.1%) cases of wound infection and 143 (73.3%) cases of limb shortening as the most common complications. Other complications include: 20 cases (17.1%) of mal-union, 27 cases (22.5%) of delayed union, 18 cases (15.1%) of non-union and 50 cases (38.5%) chronic osteomyelitis. We recorded a mortality of 2.1%. Gustilo IIIB and IIIC were associated to chronic osteomyelitis (P = 0.02). Conclusion: Open fractures of long bones of the lower limb affect the active age group of the population and road traffic crashes are the most common causes. It tends to affect the left side and the tibia being the most fractured long bone. A reasonable proportion of these fractures subsequently get infected. Comminuted fracture is the common fracture pattern.

Fracture of Limbs Bones in a Rural and Post Conflict Health Zone

Background: Trauma is major public health problem in developing countries where they are associated with many factors, mainly such as lack of road safety, poverty and inadequate urban planning. We aim to highlight the epidemiology of the fractures limbs bones in a rural area where people live in a context of low economy, low education and insecurity. Methods: We conducted a cross-sectional, retrospective study involving all patients admitted for fracture in the surgical department of FOMULAC-KATANA General Reference Hospital from 1st January 2011 to 31st December 2014. The patients whose medical records were not completed were excluded. Results: Among 136 patients included in our study, 140 bones limbs were registered. Most of them (60.1%) were aged between 15 - 44 years and the average age is 30, 1 year. Male predominance is noticed (72.8%) with a male/female ratio of 2.7/1, and informal professionals are the most found in our patients (67.6%). The main circumstances of fracture occurrence are, respectively, road traffic accidents (57.4%), falls (22.3%) and firearms (10.3%). The leg bones (33.6%) and forearm bones (20%) are the most concerned bones. Open fractures are recorded in 40.7% of patients. The supporting treatment is mainly orthopedic (64.5%) but also surgical (35.5). The mortality rate is 3.6%. Conclusion: The fractures of the limbs bones in Katana General Reference Hospital mainly affect young male which is informal professional. The road traffic accidents are the first circumstance leading to fractures followed by falls. The leg bones are the most fractured body part and fractures are commonly opened.

Pulp health and calcific healing of a complicated crown–root fracture with additional root fracture in a maxillary incisor: A case report

BACKGROUND Complicated crown–root fracture (CRF) involves severe injury to the crown, root,and pulp, and may be accompanied by multiple root fractures. The loss of a toothhas lifelong consequences for children and teenagers, but the maintenance of pulphealth and the calcific healing of multiple root fractures are rarely reported in theliterature.CASE SUMMARY This case reports healing of a permanent tooth with complicated crown–root andadditional root fractures, in which pulp health was maintained. A 10-year-old girlfell and fractured the root of her maxillary left central incisor at the cervical level.After the coronal fragment was repositioned, the tooth was splinted until thetooth was no longer mobile, 2 years later. Eight years after treatment, the toothhas remained asymptomatic with vital pulp and localized gingival overgrowth.Cone-beam computed tomography revealed not only calcified healing of the CRFbut also spontaneous healing in an additional undiagnosed root fracture. Thefracture line on the enamel could not be healed by hard tissue and formed agroove in the cervical crown. It was speculated that the groove was related to thelocalized gingival overgrowth.CONCLUSION This case provides a clinical perspective of the treatment of a tooth with acomplicated CRF and an additional root fracture.

Using fracture-based continuum modeling of coupled geomechanical-hydrological processes for numerical simulation of hydraulic fracturing

This paper describes numerical simulation of hydraulic fracturing using fracture-based continuum modeling(FBCM)of coupled geomechanical-hydrological processes to evaluate a technique for high-density fracturing and fracture caging.The simulations are innovative because of modeling discrete fractures explicitly in continuum analysis.A key advantage of FBCM is that fracture initiation and propagation are modeled explicitly without changing the domain grid(i.e.no re-meshing).Further,multiple realizations of a preexisting fracture distribution can be analyzed using the same domain grid.The simulated hydraulic fracturing technique consists of pressurizing multiple wells simultaneously:initially without permeating fluids into the rock,to seed fractures uniformly and at high density in the wall rock of the wells;followed by fluid injection to propagate the seeded fracture density hydraulically.FBCM combines the ease of continuum modeling with the potential accuracy of modeling discrete fractures and fracturing explicitly.Fractures are modeled as piecewise planar based on intersections with domain elements;fracture geometry stored as continuum properties is used to calculate parameters needed to model individual fractures;and rock behavior is modeled through tensorial aggregation of the behavior of discrete fractures and unfractured rock.Simulations are presented for previously unfractured rock and for rock with preexisting fractures of horizontal,shallow-dipping,steeply dipping,or vertical orientation.Simulations of a single-well model are used to determine the pattern and spacing for a multiple-well design.The results illustrate high-density fracturing and fracture caging through simultaneous fluid injection in multiple wells:for previously unfractured rock or rock with preexisting shallow-dipping or horizontal fractures,and in situ vertical compressive stress greater than horizontal.If preexisting fractures are steeply dipping or vertical,and considering the same in situ stress condition,well pressurization without fluid permeation appears to be the only practical way to induce new fractures and contain fracturing within the target domain.

Management and classification of the fracture of lateral process of talus:An overview and literature update

Fracture of the lateral process of the talus(FLPT)is uncommon in clinical practice and can be easily missed or misdiagnosed.In recent years,as researchers from all over the world have further deepened their research on FLPT,there has been a breakthrough in the classification,and the methods and principles of clinical management have changed accordingly;however,there is still no standardized guideline for the diagnosis and management of FLPT,and there have been few relevant literature review articles related to this kind of fracture in the past at least 5 years.In this article,we review the clinical classification,classification-based therapeutic recommendations,and prognosis of FLPT,with the aim of providing a reference for the clinical diagnosis and management of this infrequent fracture.

A modified 3D mean strain energy density criterion for predicting shale mixed-mode Ⅰ/Ⅲ fracture toughness

The fracture toughness of rocks is a critical fracturing parameter in geo-energy exploitation playing a significant role in fracture mechanics and hydraulic fracturing.The edge-notched disk bending(ENDB)specimens are employed to measure the entire range of mixed-modeⅠ/Ⅲfracture toughness of Longmaxi shale.To theoretically interpret the fracture mechanisms,this research first introduces the detailed derivations of three established fracture criteria.By distinguishing the volumetric and distortional strain energy densities,an improved three-dimensional mean strain energy density(MSED)criterion is proposed.As the critical volumetric to distortional MSED ratio decreases,the transition from tensiondominated fracture to shear-dominated fracture is observed.Our results indicate that both peak load and applied energy increase significantly with the transition from pure mode I(i.e.,tension)to pure modeⅢ(i.e.,torsion or tearing)since mode-Ⅲcracking happens in a twisted manner and mode-Ⅰcracking occurs in a coplanar manner.The macroscopic fracture signatures are consistent with those of triaxial hydraulic fracturing.The average ratio of pure mode-Ⅲfracture toughness to pure mode-Ⅰfracture toughness is 0.68,indicating that the obtained mode-Ⅲfracture resistance for a tensionbased loading system is apparent rather than true.Compared to the three mainstream fracture criteria,the present fracture criterion exhibits greater competitiveness and can successfully evaluate and predict mixed-modeⅠ/Ⅲfracture toughness of distinct materials and loading methods.

Factors Influencing Proppant Transportation and Hydraulic Fracture Conductivity in Deep Coal Methane Reservoirs

The gas production of deep coalbed methane wells in Linxing-Shenfu block decreases rapidly,the water output is high,the supporting effect is poor,the effective supporting fracture size is limited,and the migration mechanism of proppant in deep coal reservoir is not clear at present.To investigate the migration behavior of proppants in complex fractures during the volume reconstruction of deep coal and rock reservoirs,an optimization test on the conductivity of low-density proppants and simulations of proppant migration in complex fractures of deep coal reservoirs were conducted.The study systematically analyzed the impact of various fracture geometries,proppant types and fracturingfluid viscosities on proppant distribution.Furthermore,the study compared the outcomes of dynamic proppant transport experiments with simulation results.The results show that the numerical simulation is consistent with the results of the proppant dynamic sand-carrying experiment.Under the conditions of low viscosity and large pumping-rate,a high ratio of 40/70 mesh proppant can facilitate the movement of the proppant to the depths of fractures at all levels.The technical goal is to create comprehensive fracture support within intricate trapezoidal fractures in deep coal and rock reservoirs without inducing sand plugging.The sand ratio is controlled at 15%–20%,with a proppant combination ratio of 40/70:30/50:20/40=6:3:1.Proppant pumping operations can effectively address the issue of poor support in complex fractures in deep coal formations.The research results have been successfully applied to the development of deep coalbed methane in the Linxing-Shenfu block,Ordos Basin.

Borehole stability in naturally fractured rocks with drilling mud intrusion and associated fracture strength weakening:A coupled DFN-DEM approach

Borehole instability in naturally fractured rocks poses significant challenges to drilling.Drilling mud invades the surrounding formations through natural fractures under the difference between the wellbore pressure(P w)and pore pressure(P p)during drilling,which may cause wellbore instability.However,the weakening of fracture strength due to mud intrusion is not considered in most existing borehole stability analyses,which may yield significant errors and misleading predictions.In addition,only limited factors were analyzed,and the fracture distribution was oversimplified.In this paper,the impacts of mud intrusion and associated fracture strength weakening on borehole stability in fractured rocks under both isotropic and anisotropic stress states are investigated using a coupled DEM(distinct element method)and DFN(discrete fracture network)method.It provides estimates of the effect of fracture strength weakening,wellbore pressure,in situ stresses,and sealing efficiency on borehole stability.The results show that mud intrusion and weakening of fracture strength can damage the borehole.This is demonstrated by the large displacement around the borehole,shear displacement on natural fractures,and the generation of fracture at shear limit.Mud intrusion reduces the shear strength of the fracture surface and leads to shear failure,which explains that the increase in mud weight may worsen borehole stability during overbalanced drilling in fractured formations.A higher in situ stress anisotropy exerts a significant influence on the mechanism of shear failure distribution around the wellbore.Moreover,the effect of sealing natural fractures on maintaining borehole stability is verified in this study,and the increase in sealing efficiency reduces the radial invasion distance of drilling mud.This study provides a directly quantitative prediction method of borehole instability in naturally fractured formations,which can consider the discrete fracture network,mud intrusion,and associated weakening of fracture strength.The information provided by the numerical approach(e.g.displacement around the borehole,shear displacement on fracture,and fracture at shear limit)is helpful for managing wellbore stability and designing wellbore-strengthening operations.

Management of geriatric acetabular fractures:Contemporary treatment strategies

Acetabular fractures in the geriatric population are typically low-energy fractures resulting from a fall from standing height.Compromised bone quality in the elderly,as well as this population’s concomitant medical comorbidities,render the management of such fractures challenging and controversial.Non-operative management remains the mainstay of treatment,although such a choice is associated with numerous and serious complications related to both the hip joint as well as the general condition of the patient.On the other hand,operatively treating acetabular fractures(e.g.,with osteosynthesis or total hip arthroplasty)is gaining popularity.Osteosynthesis can be performed with open reduction and internal fixation or with minimally invasive techniques.Total hip arthroplasty could be performed either in the acute phase combined with osteosynthesis or as a delayed procedure after a period of non-operative management or after failed osteosynthesis of the acetabulum.Regardless of the implemented treatment,orthogeriatric co-management is considered extremely crucial,and it is currently one of the pillars of a successful outcome after an acetabular fracture.

Beyond the imaging evaluation of fractures of the lateral process of the talus:Let’s not forget concomitant injuries

Fractures of the lateral process of the talus(FLPT)are uncommon fractures that represent a clinical challenge.Traditional radiological classification systems rely predominantly on radiographic findings.However,due to the high rate of FLPT misdiagnosis and the limited accuracy in evaluating concomitant talar injuries through plain radiographs,novel imaging classification systems have been developed that aim to enhance the diagnosis of concomitant talar injuries,thereby optimizing patient management and reducing the incidence of long-term complications.

Epidemiologic investigation of pediatric distal humerus fractures: An American insurance claims database study

BACKGROUND Distal humerus elbow fractures are one of the most common traumatic fractures seen in pediatric patients and present as three main types:Supracondylar(SC),lateral condyle(LC),and medial epicondyle(ME)fractures.AIM To evaluate the epidemiology of pediatric distal humerus fractures(SC,LC,and ME)from an American insurance claims database.METHODS A retrospective review was performed on patients 17 years and younger with the ICD 9 and 10 codes for SC,LC and ME fractures based on the IBM Truven MarketScan®Commercial and IBM Truven MarketScan Medicare Supplemental databases.Patients from 2015 to 2020 were queried for treatments,patient age,sex,length of hospitalization,and comorbidities.RESULTS A total of 1133 SC,154 LC,and 124 ME fractures were identified.SC fractures had the highest percentage of operation at 83%,followed by LC(78%)and ME fractures(41%).Male patients were,on average,older than female patients for both SC and ME fractures.CONCLUSION In the insurance claims databases used,SC fractures were the most reported,followed by LC fractures,and finally ME fractures.Age was identified to be a factor for how a pediatric distal humerus fractures,with patients with SC and LC fractures being younger than those with ME fractures.The peak age per injury per sex was similar to reported historic central tendencies,despite reported trends for younger physiologic development.

Treatment of a femoral neck fracture combined with ipsilateral femoral head and intertrochanteric fractures: A case report

BACKGROUND This article presents a rare case of a complex hip fracture involving the ipsilateral femoral neck,trochanter,and femoral head,that was accompanied by hip dislocation.Currently,there is no established standard treatment method for this specific type of fracture.Therefore,it is crucial to comprehensively consider factors such as patient age,fracture type,and degree of displacement to achieve a successful outcome.CASE SUMMARY A 38-year-old man sustained a comminuted fracture of his right hip as a result of a car accident.The injuries included a fracture of the femoral head,a fracture of the femoral neck,an intertrochanteric fracture of the femur,and a posterior dislocation of the hip on the same side.We opted for a treatment approach combining the use of a proximal femoral locking plate,cannulated screws,and Kirschner wires.Following the surgery,we developed an individualized rehabil-itation program to restore patient limb function.CONCLUSION For this complex fracture,we selected appropriate internal fixation and for-mulated individualized rehabilitation,which ultimately achieved good results.

Production induced fracture closure of deep shale gas well under thermo-hydro-mechanical conditions

Deep shale gas reservoirs have geological characteristics of high temperature,high pressure,high stress,and inferior ability to pass through fluids.The multi-stage fractured horizontal well is the key to exploiting the deep shale gas reservoir.However,during the production process,the effectiveness of the hydraulic fracture network decreases with the closure of fractures,which accelerates the decline of shale gas production.In this paper,we addressed the problems of unclear fracture closure mechanisms and low accuracy of shale gas production prediction during deep shale gas production.Then we established the fluid—solid—heat coupled model coupling the deformation and fluid flow among the fracture surface,proppant and the shale matrix.When the fluid—solid—heat coupled model was applied to the fracture network,it was well solved by our numerical method named discontinuous discrete fracture method.Compared with the conventional discrete fracture method,the discontinuous discrete fracture method can describe the three-dimensional morphology of the fracture while considering the effect of the change of fracture surface permeation coefficient on the coupled fracture—matrix flow and describing the displacement discontinuity across the fracture.Numerical simulations revealed that the degree of fracture closure increases as the production time proceeds,and the degree of closure of the secondary fractures is higher than that of the primary fractures.Shale creep and proppant embedment both increase the degree of fracture closure.The reduction in fracture surface permeability due to proppant embedment reduces the rate of fluid transfer between matrix and fracture,which has often been overlooked in the past.However,it significantly impacts shale gas production,with calculations showing a 24.7%cumulative three-year yield reduction.This study is helpful to understand the mechanism of hydraulic fracture closure.Therefore,it provides the theoretical guidance for maintaining the long-term effectiveness of hydraulic fractures.

Study of hydro-mechanical behaviours of rough rock fracture with shear dilatancy and asperities using shear-flow model

The geometric properties of fracture surfaces significantly influence shear-seepage in rock fractures,introducing complexities to fracture modelling.The present study focuses on the hydro-mechanical behaviours of rough rock fractures during shear-seepage processes to reveal how dilatancy and fracture asperities affect these phenomena.To achieve this,an improved shear-flow model(SFM)is proposed with the incorporation of dilatancy effect and asperities.In particular,shear dilatancy is accounted for in both the elastic and plastic stages,in contrast to some existing models that only consider it in the elastic stage.Depending on the computation approaches for the peak dilatancy angle,three different versions of the SFM are derived based on Mohr-Coulomb,joint roughness coefficient-joint compressive strength(JRC-JCS),and Grasselli’s theories.Notably,this is a new attempt that utilizes Grasselli’s model in shearseepage analysis.An advanced parameter optimization method is introduced to accurately determine model parameters,addressing the issue of local optima inherent in some conventional methods.Then,model performance is evaluated against existing experimental results.The findings demonstrate that the SFM effectively reproduces the shear-seepage characteristics of rock fracture across a wide range of stress levels.Further sensitivity analysis reveals how dilatancy and asperity affect hydraulic properties.The relation between hydro-mechanical properties(dilatancy displacement and hydraulic conductivity)and asperity parameters is analysed.Several profound understandings of the shear-seepage process are obtained by exploring the phenomenon under various conditions.

Assessing the readability of online information about jones fracture

BACKGROUND Hand in hand with technological advancements,treatment modalities continue to grow.With the turn of the century,the internet has become the number one source of information for almost every topic.Thus,many patients look toward the internet as their primary source of information to learn about their respective medical conditions.The American Medical Association and National Institute of Health strongly recommend that online medical information be written at the 6th to 8th-grade level to aid comprehension by patients of all literacy backgrounds.AIM To assess the readability of online information regarding Jones fracture.Our hypothesis is that the reading level of medical information published on websites far exceeds the recommended reading level of 6th-8th grade as proposed by the American Medical Associate and National Institute of Health.The result of this study can help us formulate improved recommendations for publishing more comprehensible material and,thus,eventually improve patient compliance and clinical outcomes.METHODS The exact phrase“Jones fracture”was queried on the three most common search engines,Google,Yahoo!,and Bing,on December 28,2022.As of December 2022,Google held 84%,Bing held 9%,and Yahoo!held 2%of the worldwide search engine market share.Web pages uniform resource locator from the first three pages of search results were recorded from each search engine.These web pages were classified according to academic,physician-sponsored,governmental and non-government organizations(NGO),commercial,and unspecified as per formally defined categories.Websites associated with an educational institution or medical organization were classified as academic.Websites with products for sale,corporate sponsorship,or advertisements were classified as commercial.Governmental websites or NGOs comprised those that received government subsidies or grants.Webpages that were independently owned by physicians or physician groups were respectively classed as physician sponsored.The remainder of websites that did not fall under the above categories were classified as unspecified.RESULTS A total of 93 websites were analyzed for reading assessment.A whopping 44%of websites were commercial,followed by 22%of physician-sponsored websites.Third place belonged to non-government organization websites holding a 15%share.The academic website held a meager 9%portion,while unspecified sites were 3%.The table illustrates mean readability scores,along with average cumulative grade level.The average grade level was 10.95±2.28 for all websites,with a range of 6.18 to 18.90.Since P values were more than 0.05,there was not a significant statistical difference between the first page results and the results of all pages.Thus,we can rationalize that readability scores are consistent throughout all pages of a website.CONCLUSION Hand in hand with technological advancements,treatment modalities continue to grow.With the turn of the century,the internet has become the number one source of information for almost every topic.Thus,many patients look towards the internet as the primary source of information to learn about their respective medical conditions.Our study demonstrates that current online medical information regarding Jones fracture is written at an extraordinarily high-grade level,with an average grade level of all websites at 10.95,nearly an 10th-grade educational level.The American Medical Association and National Institute of Health strongly recommend that online medical information should be written at the 6th to 8th-grade level to aid comprehension by patients of all literacy backgrounds.On the contrary,most of the medical information evaluated was at an 10th-grade level,which far exceeds recommendations by AMA and NIH.This is particularly relevant because readability scores are directly proportional to the level of comprehension attained by readers,thus directly impacting patient outcomes.In conclusion,we suggest and encourage that all online reading materials should be re-written at the 6th to 8th-grade level in a public service effort to increase compliance with treatment goals and raise awareness of preventive measures.

Computer navigation-assisted minimally invasive percutaneous screw placement for pelvic fractures

Pelvic fractures are often caused by high-energy injuries and accompanied by hemodynamic instability.Traditional open surgery has a large amount of bleeding,which is not suitable for patients with acute pelvic fracture.Navigationguided,percutaneous puncture-screw implantation has gradually become a preferred procedure due to its advantages,which include less trauma,faster recovery times,and less bleeding.However,due to the complexity of pelvic anatomy,doctors often encounter some problems when using navigation to treat pelvic fractures.This article reviews the indications,contraindications,surgical procedures,and related complications of this procedure for the treatment of sacral fractures,sacroiliac joint injuries,pelvic ring injuries,and acetabular fractures.We also analyze the causes of inaccurate screw placement.Percutaneous screw placement under navigational guidance has the advantages of high accuracy,low incidence of complications and small soft-tissue damage,minimal blood loss,short hospital stays,and quick recovery.There is no difference in the incidence of complications between surgeries performed by new doctors and experienced ones.However,computer navigation technology requires extensive training,and attention should be given to avoid complications such as screw misplacement,intestinal injury,and serious blood vessel and nerve injuries caused by navigational drift.

Multiple damage zones around hydraulic fractures generated by high-frequency pulsating hydraulic fracturing

Pulsating hydraulic fracturing(PHF)is a promising fracturing method and can generate a dynamic periodic pressure.The periodic pressure can induce fatigue failure of rocks and decrease initiation pressure of fracture.If the frequency of periodic pressure exceeds 10 Hz,the distribution of pressure along the main fracture will be heterogeneous,which is much different from the one induced by the common fracturing method.In this study,the impact of this special spatial feature of pressure on hydraulic fracture is mainly investigated.A coupled numerical simulation model is first proposed and verified through experimental and theoretical solutions.The mechanism of secondary fracture initiation around the main fracture is then discovered.In addition,sensitivity studies are conducted to find out the application potential of this new method.The results show that(1)this coupled numerical simulation model is accurate.Through comparison with experimental and theoretical data,the average error of this coupled model is less than 1.01%.(2)Even if a reservoir has no natural fracture,this heterogeneous distribution pressure can also cause many secondary fractures around the main fracture.(3)The mechanism of secondary fracture initiation is that this heterogeneous distribution pressure causes tensile stress at many locations along the main fracture.(4)Through adjusting the stimulation parameters,the stimulation efficiency can be improved.The average and amplitude of pressure can increase possibility of secondary fracture initiation.The frequency of this periodic pressure can increase number of secondary fractures.Even 6 secondary fractures along a 100 m-length main fracture can be generated.(5)The influence magnitudes of stimulation parameters are larger than ones of geomechanical properties,therefore,this new fracturing method has a wide application potential.

Experimental and numerical investigation of droplet flow mechanisms at fracture intersections

Understanding unsaturated flow behaviors in fractured rocks is essential for various applications.A fundamental process in this regard is flow splitting at fracture intersections.However,the impact of geometrical properties of fracture intersections on flow splitting is still unclear.This work investigates the combined influence of geometry(intersection angle,fracture apertures,and inclination angle),liquid droplet length,inertia,and dynamic wetting properties on liquid splitting dynamics at fracture intersections.A theoretical model of liquid splitting is developed,considering the factors mentioned above,and numerically solved to predict the flow splitting behavior.The model is validated against carefullycontrolled visualized experiments.Our results reveal two distinct splitting behaviors,separated by a critical droplet length.These behaviors shift from a monotonic to a non-monotonic trend with decreasing inclination angle.A comprehensive analysis further clarifies the impacts of the key factors on the splitting ratio,which is defined as the percentage of liquid volume entering the branch fracture.The splitting ratio decreases with increasing inclination angle,indicating a decrease in the gravitational effect on the branch fracture,which is directly proportional to the intersection angle.A non-monotonic relationship exists between the splitting ratio and the aperture ratio of the branch fracture to the main fracture.The results show that as the intersection angle decreases,the splitting ratio increases.Additionally,the influence of dynamic contact angles decreases with increasing intersection angle.These findings enhance our understanding of the impact of geometry on flow dynamics at fracture intersections.The proposed model provides a foundation for simulating and predicting unsaturated flow in complex fractured networks.