Telescopic Rod Research Articles

Mechanism design and mechanical analysis of pipeline inspection robot

Purpose This study aims to address the issues of limited pipe diameter adaptability and low inspection efficiency of current pipeline inspection robots, a new type of pipeline inspection robot capable of adapting to various pipe diameters was designed. Design/methodology/approach The diameter-changing mechanism uses a multilink elastic telescopic structure consisting of telescopic rods, connecting rods and wheel frames, driven by a single motor with a helical drive scheme. A geometric model of the position relationships of the hinge points was established based on the two extreme positions of the diameter-changing mechanism. Findings A pipeline inspection robot was designed using a simple linkage agency, which significantly reduced the weight of the robot and enhanced its adaptive pipe diameter ability. The analysis determined that the robot could accommodate pipe diameters ranging from 332 mm to 438 mm. A static equilibrium equation was established for the robot in the hovering state, and the minimum pressing force of the wheels against the pipe wall was determined to be 36.68 N. After experimental testing, the robots could successfully pass a height of 15 mm, demonstrating the good obstacle capacity of the robot. Practical implications This paper explores and proposes a new type of multilink elastic telescopic variable diameter pipeline inspection robot, which has the characteristics of strong adaptability and flexible operation, which makes it more competitive in the field of pipeline inspection robots and has great potential market value. Originality/value The robot is characterized by the innovative design of a multilink elastic telescopic structure and the use of a single motor to drive the wheel for spiral motion. On the basis of reducing the weight of the robot, it has good pipeline adaptability, climbing ability and obstacle-crossing ability.

Long-term Outcomes of Intramedullary Nails in Osteogenesis Imperfecta: Fewer Surgeries and Longer Survival Times With Telescoping Rods in Patients With Over Ten Years Follow-up.

Intramedullary rodding of lower extremity long bones in patients with osteogenesis imperfecta (OI) is a widely accepted technique for fracture treatment and prevention. Previous small studies with short to medium-term follow-up have shown that telescoping rods have longer survival times compared with static rods. However, there are no long-term studies (10 or more years) longitudinally evaluating the results of these procedures. The purpose of this study was to compare the rod survival duration and number of procedures in patients treated with static versus telescoping rods with 10 years minimum follow-up. This was a multicenter retrospective comparative study of patients with a diagnosis of OI who had intramedullary nailing of the femur and/or tibia. Each bone included in the study had a 10-year minimum follow-up, only one type of rod utilized over the follow-up period, and no rod replacement surgeries outside of the primary hospital system. Patient demographics, clinical data, and details of each procedure were obtained. Groups were compared using univariate analysis with a 2-independent samples t test for continuous variables, χ2 for categorical variables, and the Kaplan-Meier method for survival analysis. A total of 119 bones in 52 patients met inclusion criteria. Average follow up was 13.1 (range: 10.2 to 18.4) years. There were no differences between groups in follow-up length, Sillence type, bisphosphonate use, or age at first-rod placement. There were significantly more tibias treated in the static rod group compared with the telescopic rod group. The average survival length was significantly longer for telescopic rods, 5.8 ± 3.9 years versus 4.0±3.6 years for static rods. On average, bones treated with telescopic rods had significantly fewer surgeries compared with static rods (2.2 ± 0.8 vs 3.3 ± 1.6). At long term follow up, bone segments in patients with OI treated with telescopic rods required fewer surgeries and had longer implant survival times compared with those treated with static rods. When available, surgeons should consider telescopic rods as the initial implant choice in this patient population.

FPID-RCP: A Control Method for a Swing-Type Wave Compensation Platform System

With the rapid development of marine engineering in recent years, offshore operations have become increasingly common, making wave compensation platforms crucial for safe operations at sea. This paper presents a pendulum-type wave compensation platform specifically designed for wave compensation applications. The main components of this wave compensation platform include a chassis, support base, hydraulic cylinders, telescopic rods, upper platform, three sets of balancing mechanisms, three sets of tilt angle sensors, and a control system. Firstly, to thoroughly understand the compensatory motion of the pendulum-type three-degree-of-freedom wave compensation platform, kinematic analysis of the entire system was conducted, and the motion inverse solution curves of the mechanism were obtained through simulation using motion simulation software. Secondly, to enhance the compensatory response performance of the platform, a fuzzy PID control algorithm was employed to control the system and achieve attitude control of the platform. Finally, through control system simulation, compared to PID control, fuzzy PID reduces system response delay and successfully meets the expected technical requirements and application needs.

Total Hip Replacement and Femoral Nail Lengthening for Hip Dysplasia and Limb Length Discrepancy: A Literature Review.

Developmental dysplasia of the hip (DDH) is a serious condition resulting in inadequate acetabular development, distorted bone configuration, and substantially alteredhip biomechanics. An extensive leg length discrepancy (LLD) is commonly encountered in such cases, making a total hip arthroplasty (THA) procedure extremely challenging. Although good results in terms of patients' satisfaction, implant survival rates and overall improved quality of life have been reported, complication rates are considerably higher than primary THA procedures performed for idiopathic osteoarthritis. Reconstructing a dysplastic hip arthrosis and equalizing a preexisting LLD is a technically demanding procedure that is associated with significant bone and soft tissue complications. Intramedullary lengthening through motorized nails has become increasingly popular to address difficult cases with extensive LLD following THA in recent years. However, limited data on femoral lengthening procedures implemented following THA are available considering complications, radiological results, and patient-reported outcomes following staged THA and subsequent femoral lengthening using a femoral magnetically-driven intramedullary lengthening nail. We performed a literature review of the past 10 years in PubMed using the terms neglected hip dislocation, DDH, THA, and intramedullary lengthening nail as keywords. A total amount of eight cases addressing LLD through a telescoping intramedullary nail following THA in DDH have been reported in recent literature. All eight patients underwent primary THA for DDH followed by the implantation of the intramedullary lengthening nail. The mean THA was lengthened by 28.9 mm (from 13.0 to 45.0). The mean time for nail implantation after THA was 11.1 months (from 3.5 to 21). The mean time for lengthening per day through the nail was 0.94 mm (from 0.65 to 1.0) from 26 days to 70 days, and the mean lengthening through the nail was 37.6 mm (from 24.0 to 70.0). Good union and consolidation rates were reported by the authors, while there were no complications. The intramedullary distraction osteogenesis method with a telescopic rod can be an effective method to manage leg length discrepancies while avoiding soft tissue complications in challenging cases of DDH.

Evaluating the use of unmanned aerial vehicles for spray applications in mountain Nanguo pear orchards.

Nanguo pear is a distinctive pear variety in northeast China, grown mainly in mountainous areas. Due to terrain limitations, ground-based pesticide application equipment is difficult to use. This limitation could be overcome by using unmanned aerial vehicles (UAVs) for pesticide application in Nanguo pear orchards. This study evaluated the spraying performance of two UAVs in the Nanguo pear orchards and compared them with a manually used backpack electric sprayer (BES). The study also analyzed the effect of canopy size on droplet deposition and ground loss, and evaluated two sampling methods, leaf sampling and telescopic rod sampling. Compared to BESs, droplet deposition is lower for UAVs, but the actual pesticide active ingredient deposition is not necessarily lower given the solution concentration. The droplet deposition varies among different UAVs due to structural differences. Under the same UAV operating parameters, droplet deposition on trees with smaller canopy sizes is typically greater than that on trees with larger canopy sizes, and the ground loss was also more severe. Although telescopic rod sampling is a quick and convenient method, it can only reflect the trend of droplet deposition, and the data error is greater compared with leaf sampling. UAVs can achieve better droplet deposition in mountainous Nanguo pear orchards and does almost no harm to the operators compared with the BES. However, canopy size needs to be considered to adjust the application volume rate. Telescopic rods can be used for qualitative analyses, but are not recommended for quantitative analyses. © 2024 Society of Chemical Industry.

Analysis and Optimization of Telescopic Drill Rod Structure Based on SolidWorks

In this paper, the structural performance of the telescopic drill pipe structure is optimized and analyzed. The main working principle of the telescopic drill pipe is to drive the two internal telescopic rods through the two-stage telescopic cylinder, so that it can produce stable reasoning and motion characteristics. The 3D model of the telescopic drill pipe is also established by using SolidWorks software. The simulation of SolidWorks module is used to analyze the dynamic characteristics of the two-stage telescopic drill pipe, including the first five modal shapes, static stress and fatigue life of the structure. The distribution law of the maximum stress distribution point and the easily damaged position is found, and the structural design is optimized, which provides a reliable structural design scheme for improving the fatigue strength of the telescopic rod and prolonging the life cycle of the equipment.

Surgical treatment of osteogenesis imperfecta: a summary of the incidence of femoral implant-related complications in children with Sillence type I, III and IV.

This study explored the incidence of IRCs used in the procedures of the femur in children with osteogenesis imperfecta (OI) and investigated the independent risk factors of IRCs. Three hundred eight-eight cases of surgical data about children with OI were included, who were treated with plate, elastic nail, Kirschner wire and telescopic rod. The choice of different procedures depended on the age of children, the status of femur and the availability of devices. Patient demographics and major IRCs were recorded to compare the outcomes of the four procedures. Then, Cox proportional hazard regression was used to analyse the independent risk factors of IRC, and subgroup analysis was applied to further verify the above results. The total incidence of IRC in the four groups was 90.1% (191/212) for plate, 96.8% (30/31) for Kirschner wire, 87.7% (57/65) for elastic nail and 30.0% (24/80) for telescopic rod. The incidence of IRC in the telescopic rod was lower than that in plate, elastic nail and Kirschner wire (P < 0.001). Cox proportional hazard regression analysis confirmed that procedure was the independent risk factor of IRC (HR, 0.191; 95% CI, 0.126-0.288; P < 0.001), fracture (HR, 0.193; 95% CI, 0.109-0.344; P < 0.001) and deformity (HR, 0.086; 95% CI, 0.027-0.272; P < 0.001). In addition, age of surgery was the independent risk factor of fracture (HR, 0.916; 95% CI, 0.882-0.952; P < 0.001) and deformity (HR, 1.052; 95% CI, 1.008-1.098; P = 0.019). Subgroup analysis confirmed that age of surgery, gender, classification, preoperative state and angle did not affect the effect of telescopic rod on reducing the risk of IRCs. In our cohort, lower incidence of IRCs was observed in telescopic rod group compared with plate, Kirschner wire and elastic nail. Procedure and age of surgery were independent risk factors of fracture. Likewise, procedure and age of surgery were independent risk factors of deformity, and procedure was independent risk factors of IRC.

Correction of anterior bowing complicating tibial osteofibrous dysplasia in preadolescents by osteotomy and telescopic nailing without lesional resection: a preliminary study of four-case reports.

Osteofibrous dysplasia (OFD) occurs most frequently in the tibia and may result in deformity and pathological fracture. Surgical treatment such as curettage or segment excision has been performed but remains controversial due to high complication rates and surgical burden. This study introduces a new method to manage OFD with anterior bowing of the tibia using minimally invasive tibial osteotomy and telescopic rod (TR) osteosynthesis without extensive lesion resection. A retrospective study of 4 children with OFD and tibia bowing deformity treated with minimally invasive tibial wedge osteotomy and TR fixation between January 2015 and November 2020 was performed. Results including bone healing, complications, function based on MSTS score, and recurrance of deformity were assessed. The median follow-up was 29 months. Radiographs showed the median time for union was 3 months. There were no instances of refracture or recurrence of deformity. The mean post-operative MSTS score was significantly higher than preoperative score. This method avoids large bone defects and reconstructive procedures. It is an effective and minimally invasive approach for managing anterior bowing deformity secondary to OFD while improving function and quality of life. Level IV; Case Series; Treatment Study.

Combination of flexible intramedullary nailing and Ilizarov frame for salvage of femur and humerus nonunion in a girl with osteogenesis imperfecta

Background Fixation of pathological long bones with telescopic intramedullary rods is well known to be a technically challenging procedure even in specialist centres, with a high complication rate due to rod migration, hardware failure, nonunion or malunion. However there is very little guidance in the literature regarding salvage treatment options when failure occurs.Aim We demonstrate a surgical technique that can be used for salvage treatment of both femoral and humeral complex nonunions following Fassier-Duval (FD) rodding in a child with osteogenesis imperfecta (OI).Case description A 13 year-old girl with OI type VIII presented sequentially with nonunion and deformity of the femur then the humerus following previous FD rods in those segments. The femur was also complicated with metallosis between the steel rod and an overlying titanium plate. Both segments were treated with pseudarthrosis debridement, removal of metalwork and stabilisation with hydroxyapatite (HA)-coated flexible intramedullary nails, with temporary Ilizarov frame to provide enough longitudinal and rotational stability to allow immediate weight-bearing. The femur Ilizarov frame was removed after 64 days, and the femur remained straight and fully healed at 2.5 years. The frame time for the humerus was 40 days, complete union was achieved and upper limb function restored and maintained at 9 months.Discussion The transphyseal telescopic rod is the traditional implant of choice in terms of treating fractures and stabilising osteotomies for deformity in OI. However, it does not provide enough torsional or longitudinal stability by itself to allow early weight-bearing which is detrimental to bone healing in this vulnerable patient group. The incidence of delayed union or nonunion at osteotomy site in telescopic rod application is not negligible: up to 14.5-51.5 %. Although the technique we have shown in this case may not be applied to all complex OI patients, we believe that the combination of flexible intramedullary nails and Ilizarov frame provides a favourable environment for bone healing in complex or revision cases. As a secondary learning point the initial revision surgery to the left femur demonstrated the perils of using a steel rod and a titanium plate in a biologically active environment which in this case lead to metallosis and lysis.Conclusion We found the technique of HA-coated flexible intramedullary nails combined with the Ilizarov frame effective in the salvage of failed telescopic rods in both femur and humerus and feel this technique can be used as a salvage option in similar cases worldwide. This case also demonstrates the perils of using different metals in combined internal fixation.

Kinetostatics of Deployable Concrete Formworks

Abstract To reform the traditional concrete formwork, an overconstrained deployable frame is designed. It is composed of closed-loop deployable units formed by scissor-form elements and orthogonal telescoping rods. Using the reciprocal screw theory, the mobility of the deployable frame is studied, and it has one degree of freedom (DoF). To analyze the kinematic performance of the frame in the deployment and folding processes and the static characteristics under external loads at different deployed states, a general approach to analyzing the kinematics and statics by modeling in screw form is proposed. The velocities of joints could be solved in screw coordinates, the position and acceleration of joints could be obtained via a first-order numerical integration and a first-order numerical differential interpolation, respectively. Then, the position information for each joint can be forwarded onto the static equilibrium equations. Through the static analysis at each deployed state, the inner forces in each rod and the active control forces are derived. Kinematics and statics are associated by using velocities as the global variable, which allows a unified analysis of mechanisms. This method is computationally highly efficient and also fits for kinematic and static analysis of different kinds of multi-rigid-body mechanisms.

Complications among patients with osteogenesis imperfecta following surgical interventions

Objectives: Osteogenesis imperfecta (OI) is a genetic bone disorder caused mainly by a defect in the COL1A1 or COL1A2 genes. This study aimed to analyze the complication using surgical interventions, including intramedullary telescopic rod fixation, Rush pin fixation, and Kirschner-wire (K-wire) fixation. Methods: This retrospective and cohort study was conducted in our institution, Riyadh, Saudi Arabia. A total of 23 patients with OI were treated from 2018 to 2022, out of which 19 were treated surgically. A total of 29 long bones were surgically managed. Our patients’ data were collected from the hospital’s electronic system. Results: The overall incidence of Rush pin fixation post-operative complications was 57% (five out of seven cases) and K-wire fixation was 50% (one out of two cases). The main indications for intramedullary telescopic rod implantation were osseous deformities and fractures, with the overall incidence of post-operative complications reaching around 35% (seven out of 20 cases). Conclusion: In our population, the overall incidence of complications after intramedullary telescopic rod fixation was lower than those after Rush pin fixation and K-wire fixation. In addition, more studies are needed to add to the literature new ways of tackling post-operative complications following the insertion of intramedullary telescopic rods, such as nail migration and new fractures or refractures.

Development, analysis, and verification of an intelligent auxiliary beekeeping device mounted on a crawler transporter

The transportation of beehives poses a significant challenge in the beekeeping industry. To address the manual handling practices prevalent in the beekeeping industry and enhance the automation level, this study attempts the design and development of a mobile auxiliary beekeeping device mounted on a caterpillar vehicle for beehive transportation. Specifically, the design of the auxiliary device was completed in SolidWorks with the notion of the cylindrical mechanical arm. Subsequently, a dynamic model of the simulated environment is constructed using RecurDyn, facilitating the determination of the torque requirements for each joint based on the dynamic model. Furthermore, the multi-flexible body dynamics analysis is utilized to conduct a flexible analysis of the auxiliary beekeeping device’s three principal components and the maximum beehive weight, which can be safely transported, is estimated through simulation analysis. Particularly, field experiments involve the use of strain gauges to measure the stress exerted on the components of the auxiliary beekeeping device during actual beehive transportation. Additionally, it incorporates the errors and precision associated with each joint, and the planar positioning accuracy result. Meanwhile, the maximum torque required for the joints, which is about 5 N·m was determined by simulation results, affirming that the selected drive motors can meet the operational requirements. Through simulation, it is determined that the auxiliary device can handle a maximum beehive weight of 126 kg, approximately three times the weight of the standard beehives (40 kg) utilized in beekeeping farms. This ensured that the auxiliary device poses no risk of overturning during the beehive transportation. In addition, the stress levels at crucial locations are ascertained through on-site strain experiments. Interestingly, the auxiliary support part (57.68 MPa) and the spindle connection (58.8 MPa) experienced the highest stress levels; and the stress levels in the telescopic rod and lower support part remained below 5 MPa. In particular, these stress levels fall within the permissible range of the materials employed (200 MPa), which ensures the auxiliary device’s safe utilization. An evaluation of each joint’s operational accuracy showed that the planar positioning accuracy result of joint 1 and joint 2 is 9.65 mm for 50% CEP and 23.55 mm for 95% CEP, respectively. Furthermore, the highest final error was exhibited by the vertical extension joint (11.48 mm), indicating that the auxiliary device can successfully accomplish the beehive transportation tasks within beekeeping farms. Overall, this research provides a solid foundation for the subsequent development of automated beehive handling devices.

Non-invasive detection of Orthohalarachne attenuata (Banks, 1910) and Orthohalarachne diminuata (Doetschman, 1944) (Acari: Halarachnidae) in free-ranging synanthropic South American sea lions Otaria flavescens (Shaw, 1800).

Respiratory mites of the genera Orthohalarachne and Halarachne (Acari: Halarachnidae) are causative agents of nasopharyngeal/nasopulmonary acariasis in pinnipeds and sea otters. Until now, these endoparasitic mites were mainly diagnosed via necropsies and invasive procedures. So far, non-invasive diagnostic techniques have neither been developed nor applied in free-ranging pinnipeds. In the current study, we aimed to evaluate the halarachnid mite infestation status of free-ranging "urban" South American sea lions Otaria flavescens in the city of Valdivia, Chile. Therefore, non-invasive sampling methods were used in the current study, e. g. by observation-based sampling of freshly expectorated nasal mucus in the animal environment. Further, collection devices were developed for target-oriented sampling of sneezed nasal mucus, including sterile petri dishes and stretched clingfilms mounted on telescopic rods. Applying these techniques, 26 individual sputum samples were collected. 11.5% of sputum samples proved positive for halarachnid larvae (in total, n=7), which were morphologically identified as Orthohalarachne attenuata (n=2) or Orthohalarachne diminuata (n=5). In one of the individual sea lion mucus samples, both Orthohalarachne species were detected, thereby confirming a patent co-infestation in vivo. 16S rDNA-based molecular identification of individual Orthohalarachne spp. larvae confirmed morphological findings. For the first time, we here molecularly characterized Orthohalarachne spp. on the basis of three gene regions [18S, 28S and the internal transcribed spacer 1 (ITS1)]. Overall, current data include the successful application of non-invasive techniques to sample halarachnid mites from free-ranging synanthropic pinnipeds and contribute to the current knowledge on respiratory mites infesting South American sea lions by combining morphological and molecular methods to overcome challenges in species identification. This study should further serve as baseline study and calls for more research on occurrence, biology and health implications of orthohalarachnosis in free-living as well as captive pinnipeds.

Design, modeling and solar tracking control for a novel parabolic dish solar concentrator

AbstractA novel parabolic dish solar concentrator based on the improved 3-RPS parallel manipulator to drive the reflective mirror facet is proposed and designed, which can not only automatically adjust the position and orientation of the reflective mirror facet but also have the advantages of independent drive, high stiffness and no cumulative error. Then, using the coordinate transformation matrixes of the novel parabolic dish solar tracking platform, the kinematics models of the 3-RPS parallel manipulators associated with the solar altitude and azimuth angles are established. The altitude and azimuth angles of the solar movement at the installation location are calculated according to the calculation formula of solar position. To solve the problem of too many telescopic rods of the 3-RPS parallel manipulator, a genetic algorithm is used to optimize the height of the concentrator’s center of mass. Then the ideal trajectory and attitude of each telescopic rod of the 3-RPS parallel manipulators at different times of the day can be obtained with the inverse kinematics. The particle swarm optimization (PSO)-proportional-integral-derivative (PID) controller, which uses PSO algorithm to tune PID parameters, is proposed for solar trajectory tracking of the novel parabolic dish solar concentrator. The visual simulation model of the parabolic dish system is established in Simscape Multibody, and the trajectory tracking control experiment is carried out. The experimental results show that the trajectory tracking error of the novel dish solar tracking platform can be within 2.6 mm by using the PSO-PID controller.

Impact of telescopic intramedullary rodding on the growth of tibia: Comparative experimental study in dogs

IntroductionThe most commonly accepted method of long bone deformity correction in children with osteogenesis imperfecta is surgical realignment with transphyseal telescopic intramedullary rodding. This approach ensures reinforcement of the bone throughout the growth period. Although longitudinal growth does occur with these implants there has been very little work carried out to calculate the effect of such factors as rod position or implant material on growth. We carried out a prospective comparative study on 12 puppies using titanium alloy telescopic tibial rods with and without hydroxyl-apatite coating. The aim of this non-randomized controlled experimental study was to assess the impact of telescopic intramedullary rodding on spontaneous growth of the tibia. Material and methodsTwelve mongrel puppies aged of 5 months underwent intramedullary transphyseal rodding of the right tibia. In group I (6 dogs) a titanium telescopic rod was used, in group II (6 dogs) a titanium rod with hydroxyapatite (HA)-coated threaded end was used. The following radiological criteria were assessed before surgery and every month until age of 12 months (natural fusion of physes in dogs): length of tibia, amount of superposition of inner (male) rod into external (female) rod; alteration of anatomy in terms of joint angles (mMPTA, mLDTA, mPPTA, mADTA); positioning of threaded ends in proximal and distal epiphyses and evidence of premature growth arrest. Parameters were compared with left tibia serving as control segment. The null hypothesis was that neither rod position nor implant material altered growth. ResultsThe transphyseal rods did not lead to irreversible epiphysiodesis in either group. In group II (HA-coated) some loss of residual length was found in all six dogs, over 7mm (5.9%) in comparison to left intact tibia. In contrast to that, in group I (titanium nail) only one animal (16.7%) demonstrated a tibia length discrepancy of 8mm (4.8%). Eccentric ( posterior) positioning of the rod in the distal epiphysis resulted in a procurvatum deformity (increased anterior distal tibial angle) in both groups. We found no failure of telescoping and no loss of fixation of threaded parts in either epiphyses. DiscussionThe presence of telescopic rods with HA-coated threads parts clearly contributes to inhibition of spontaneous longitudinal growth. We hypothesize that HA stimulates maturation of chondrocytes of growth plate. Our findings regarding the potential adverse effect of thread position in the distal physis demonstrate the importance of attempting to place the rod as central as possible. ConclusionTitanium alloy telescopic rods did not reveal significant effect on physeal growth in puppies in comparison to HA-coated implants. Transphyseal HA-coated implants did however inhibit growth plate function with mean loss of length of 5.2% compared to the other side. Eccentric positioning of rods relative to center of physis resulted in angular deformity due to irregular growth. There were no cases of mechanical failure or loss of telescopic function with either group of titanium implant. Level of evidenceII; prospective comparative experimental study.

The results of the use of the telescopic intramedullary system in the surgical treatment of patients with osteogenesis imperfecta types I and III

Background. The main orthopedic manifestation of osteogenesis imperfecta is multiple fractures. In severe disease, frequent fractures lead to malunion and deformity, which increases the risk of refracture. Surgical treatment of children with osteogenesis imperfecta is aimed at reducing the risk of complications and improving the quality of life of the child. The Fassier-Duval telescopic intramedullary system has taken the leading place among the growing metal fixators. In this study, we conduct a comparative analysis of the results of a longitudinal study between patients with osteogenesis imperfecta types I and III, as well as an assessment of motor activity.&#x0D; Aim. To evaluate the efficiency of using the telescopic intramedullary system depending on the type of osteogenesis imperfecta.&#x0D; Materials and methods. A prospective analysis of surgical treatment of 20 children with types I and III was carried out. Group I included 8 patients with type I NO, group II included 12 with type III. The average age of patients was 8.2 years. Surgical treatment was carried out on the basis of the neuroorthopedic department with orthopedics of the National Medical Research Center for Children's Health. A total of 48 intramedullary telescopic pins were installed. The average period of postoperative dynamic follow-up was 42 months. The analysis of the results of surgical treatment was carried out according to the following criteria: the frequency of migrations of metal structures, the formation of bone deformities, the number of revisions, as well as the number of bone fractures with an installed metal fixator. Evaluation of the results of motor activity was carried out using two scales: Gillette Functional Assesment Questionnaire (Gillette FAQ) and HofferBullock.&#x0D; Results. There were no statistical differences in the number of complications in the two groups. Fractures among patients with type I occurred more often than in patients with type III by 19.3%. The frequency of migrations in the I study group was 7.1% (1 segment), in the II group 35.3% (12 segments). The formation of deformation was the main factor in the revision intervention, which in our case amounted to 83.3%. In the group of patients with type I, the number of repeated operations was 7.1% (1 segment in 1 patient), in the group of patients with type III 17.6% (6 segments in 4 patients). All patients in the postoperative period had II or I level of motor capabilities on the HofferBullock scale. According to the Gillette FAQ scale in the postoperative period, the subjects showed a result above 4 points.&#x0D; Conclusion. The Fassier-Duval telescopic rod is a modern and reliable metal fixator. Despite the absence of statistical differences in the two study groups (p-value20.005), there was an increase in the tendency to complications in severe course with NO. Correction of varus deformation when restoring normal values of DN125 and HEA within 2538 is the prevention of the re-formation of the truth of Coxa Vara. The motor activity of children with severe course did not statistically differ from children with mild course (p-value20.005) in the postoperative period with an average follow-up period of 42 months, regardless of the initial low motor capabilities in children with type III.

EE29 Cost-Effectiveness Analysis and Budgetary Impact of Telescopic Rods for Treatment of Fractures and Correction of Bone Deformities in Children with Osteogenesis Imperfecta in the Brazilian Public Health System

Osteogenesis imperfecta is a rare genetic disease characterized by bone fragility, recurrent fractures and bone deformities. Telescopic rods are used to correct deformities and prevent fractures, with the benefit of extending along with the child's growth, which avoids the need of revision surgeries to change it. The objective was to evaluate the efficacy, safety, cost-effectiveness and budgetary impact of telescopic rods in children with osteogenesis imperfecta in comparison with non-extensible implants for their incorporation into the Brazilian Healthcare System.

Research on the Comparison Properties of PDMS Specimens Demolding Processes and the Mechanical Performance of Hollow-Solid Ratios of Flexible Telescopic Rods.

The main motivation of this work was to demonstrate a hollow telescopic rod structure that could be used for minimally invasive surgery. The telescopic rods were fabricated using 3D printing technology to make mold flips. During fabrication, differences in biocompatibility, light transmission, and ultimate displacement were compared between telescopic rods fabricated via different processes, so as to select the appropriate process. To achieve these goals, flexible telescopic rod structures were designed and 3D-printed molds were fabricated using Fused Deposition Modeling (FDM) and Stereolithography (SLA) techniques. The results showed that the three molding processes had no impact on the doping of the PDMS specimens. However, the FDM molding process had lower surface flatness accuracy compared to SLA. The SLA mold flip fabrication exhibited superior surface accuracy and light transmission compared to the other methods. The sacrificial template method and the use of HTL direct demolding technique had no significant impact on cellular activity and biocompatibility, but the mechanical properties of the PDMS specimens were weakened after swelling recovery. The height and radius of the hollow rod were found to have a significant impact on the mechanical properties of the flexible hollow rod. The hyperelastic model was fitted appropriately with the mechanical test results, and the ultimate elongation increased with an increase in hollow-solid ratios under the uniform force.

High-efficiency inverse dynamics modeling of parallel posture alignment mechanism with actuation redundancy

AbstractThe analytical expression of driving force is helpful to quickly plan the kinematic trajectory of parallel mechanism for automatic drilling and riveting. For parallel posture alignment mechanism, because of its closed-loop characteristics, the inverse dynamic solution is more complex, especially for parallel bracket with actuation redundancy. Considering that the telescopic rods are actually flexible parts, the dynamic analytical modeling is carried out with deformation supplementary equation. Taking the force at the spherical joint as the intermediate variable and the driving force of each active prismatic pair are analytically analyzed by vector cross-product. The modeling was verified by experiment. Compared with previous research methods, the analytical method proposed improves the solution accuracy of driving force slightly and reduces the driving force solution time by 56.28%, which is high efficiency. The maximum error percentage is 1.61%, and the experimental results show that the method of inverse dynamics modeling is practical. This paper can be used for driving force analysis of parallel posture alignment mechanism based on positioner in the field of aircraft assembly.

The Fate of the Bent Rod in Children With Osteogenesis Imperfecta.

Osteogenesis imperfecta (OI) is a genetic disorder characterized by brittle bones and long bone deformity. Realignment and intramedullary rodding with telescopic rods are indicated for progressive deformity and can help prevent fractures. Rod bending is a reported complication of telescopic rods and a common indication for revision; however, the fate of bent lower extremity telescopic rods in the setting of OI has not been reported. Patients with OI at a single institution who underwent lower extremity telescopic rod placement with at least 1-year follow-up were identified. Bent rods were identified, and for these bone segments, we collected the location and angle of bend, subsequent telescoping, refracture, increasing angulation of bend, and date of revision. One hundred sixty-eight telescopic rods in 43 patients were identified. Forty-six rods (27.4%) bent during follow-up, with an average angulation of 7.3 (range: 1 to 24) degrees. In patients with severe OI, 15.7% of rods bent compared with 35.7% in nonsevere OI ( P =0.003). The proportion of bent rods was different between independent and nonindependent ambulators (34.1% and 20.5%; P =0.035). Twenty-seven bent rods (58.7%) were revised, with 12 rods (26.0%) revised early (within 90 d). The angulation of rods that were revised early was significantly higher than rods not (14.6 and 4.3 degrees, P <0.001). Of the 34 bent rods not revised early, the average time to revision or final follow-up was 29.1 months. Twenty-five rods (73.5%) continued to telescope, 14 (41.2%) increased in angulation (average 3.2 degrees), and 10 bones (29.4%) refractured. None of the refractures required immediate rod revision. Two bones had multiple refractures. Bending is a common complication of telescopic rods in the lower extremities of patients with OI. It is more common in independent ambulators and patients with nonsevere OI, possibly because of the increased demand placed on the rods. Rods with a small bend and maintained fixation can telescope and need not be an indication for immediate revision. Level III-Retrospective review.