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Öğe Biomechanical assessment of patellar tendon advancement in patients with cerebral palsy and crouch gait(Elsevier, 2021) Karabulut, Derya; Arslan, Yunus Ziya; Salami, Firooz; Wolf, Sebastian; Götze, MarcoBackground: Patellar height is a valuable measure to evaluate the effect of patellar tendon advancement (PTA) on knee function. In the literature, there is no validated procedure to measure the patellar height. In this study we aimed to (1) determine the patella position through musculoskeletal modeling, (2) investigate the effects of two surgical procedures applied for PTA, and (3) assess the effect of PTA in combination with single-event multilevel surgery (SEMLS) on the knee kinematics of patients with cerebral palsy (CP) and crouch gait. Method: Three-dimensional gait and X-ray data of children with CP and crouch gait were retrospectively analyzed if they had received a SEMLS in combination with PTA (PTA group, n = 18) or without PTA (NoPTA group, n = 18). A computational musculoskeletal model was used to quantify patella position, knee extension moment arm, and knee kinematics pre and postoperatively. Results: Patellar height significantly decreased in the PTA group (P = 0.004), while there was no difference in the NoPTA group (P > 0.05). The bony procedure for PTA provided a better Insall-Salvati ratio than the soft tissue procedure. The peak knee extension moment arm significantly increased in the PTA group (P = 0.008). In terms of postoperative knee joint kinematics, the PTA group was closer to typically developed children than the NoPTA group. Conclusion: Musculoskeletal modeling was found to be an effective tool for the determination of the patellar height. PTA improved the patella position, knee extension moment arm, and knee kinematics and was an effective procedure for the surgical management of crouch gait in patients with CP. (c) 2021 Elsevier B.V. All rights reserved.Öğe Biomechanical comparison of implantation approaches for the treatment of mandibular total edentulism(Proceedings of the institution of mechanical engineers part h-journal of engineering in medicine, 2020) Arslan, Yunus Ziya; Karabulut, Derya; Kahya, Songül; Cansız, ErolApplying four anterior implants placed vertically or tilted in the mandible is considered to provide clinically reasonable results in the treatment of mandibular posterior edentulism. It is also reported that a combination of four anterior and two short posterior implants can be an alternative approach for the rehabilitation of severe atrophy cases. In this study, we aimed to evaluate the biomechanical responses of three different implant placement configurations, which represent the clinical options for the treatment of mandibular edentulism. Three-dimensional models of the mandible, prosthetic bar, dental implant, abutment, and screw were created. Finite element models of the three implant configurations (Protocol 1: Four anterior implants, Protocol 2: Four anterior and two short posterior implants, Protocol 3: Two anterior and two tilted posterior implants: All-on-4™ concept) were generated for 10 patients and analyzed under different loading conditions including chewing, biting, and impact forces. Protocol 2 led to the lowest stress concentrations over the mandible among the three protocols (p < 0.016). Protocol 2 resulted in significantly lower stresses than Protocol 3 and Protocol 1 over prosthetic bars under chewing forces (p < 0.016). None of the implant placement protocols consistently exhibited the lowest stress distribution over abutments. The lowest stresses over dental implants under the chewing, biting, and impact forces were obtained in Protocol 1, Protocol 2, and Protocol 3, respectively (p < 0.016). Protocol 3 was the best option to obtain the lowest stress values over the screws under all types of loading conditions (p < 0.016). In conclusion, Protocol 2 was biomechanically more ideal than Protocol 1 and Protocol 3 to manage the posterior edentulism.Öğe Direct validation of model-predicted muscle forces in the cat hindlimb during locomotion(Journal of Biomechanical engineering-transactions of the asme, 2020) Arslan, Yunus Ziya; Karabulut, Derya; Doğru, Suzan Cansel; Herzog, Walter; Pandy, Marcus G.; Lin, Yi-ChungVarious methods are available for simulating the movement patterns of musculoskeletal systems and determining individual muscle forces, but the results obtained from these methods have not been rigorously validated against experiment. The aim of this study was to compare model predictions of muscle force derived for a cat hindlimb during locomotion against direct measurements of muscle force obtained in vivo. The cat hindlimb was represented as a 5-segment, 13-degrees-of-freedom (DOF), articulated linkage actuated by 25 Hill-type muscle-tendon units (MTUs). Individual muscle forces were determined by combining gait data with two widely used computational methods—static optimization and computed muscle control (CMC)—available in opensim, an open-source musculoskeletal modeling and simulation environment. The forces developed by the soleus, medial gastrocnemius (MG), and tibialis anterior muscles during free locomotion were measured using buckle transducers attached to the tendons. Muscle electromyographic activity and MTU length changes were also measured and compared against the corresponding data predicted by the model. Model-predicted muscle forces, activation levels, and MTU length changes were consistent with the corresponding quantities obtained from experiment. The calculated values of muscle force obtained from static optimization agreed more closely with experiment than those derived from CMC.Öğe Effect of a pedicle screw fixation system on lumbar spinal segments: A finite element study(2023) Karabulut, Derya; Doğru, Suzan Cansel; Sürmen, Hasan Kemal; Yaman, Onur; Arslan, Yunus ZiyaSpinal implants have been used to stimulate fusion by surgical adjustment and correct abnormal alignment of the vertebral column. Spinal fusion can cause some spinal disorders and hence describing the changes in biomechanical forces would help to understand these complications. In this study, we used two lumbar models. One of them is used without the fixed pedicle screw system, and the other one was used with that system. Therefore, we aimed to investigate the biomechanical effect of a pedicle screw fixation system on the lumbar functional spinal unit under applied forces. Material and Methods: Computed tomography data of a scoliotic patient was used for the construction of the lumbar models. The second and third vertebrae (L2- L3) of the lumbar spine, two facet joints, an intervertebral disc, and ligaments were constructed. A screw fixation system was employed and Von-Mises stress analysis was carried out for both models. Results: The von Mises stress distribution results showed that the presence of fixed implantation transmitted the compressive forces to the screws and rods in all directions and decreased the stress levels considerably by allowing to stabilize the model. The upper side of the L2 vertebra was the most affected region in flexion and lateral bending. However, the pedicle region had the maximum affected area under applied loads in extension and axial rotation. Conclusion: It was concluded that a fixed implant system preserves the maintenance of the vertebral column and decreases the stress on the adjacent spinal segments, especially for the intervertebral discs.Öğe Evaluation of treatment protocols in surgically assisted rapid maxillary expansion by finite element analysis(2024) Arslan, Yunus Ziya; Cihaner , Duygu; Karabulut, Derya; Dogan Onur, Ozen; Cansiz, ErolBackground and Objectives: Transverse maxillary deficiency is an important maxillary anomaly that is very common in society and remains current in orthodontics. The maxillary expansion has been used in treatment for a long time. While maxillary expansion can be performed with rapid maxillary expansion in young adults, it is performed with surgically assisted rapid maxillary expansion (SARME) in individuals who have reached skeletal maturity. No consensus has been reached on the most successful surgical technique or the ideal appliance for treating transverse maxillary deficiency. Accordingly, we aimed to evaluate various surgical techniques and orthodontic appliances for treating transverse maxillary deficiency using the finite element method (FEM) to identify the treatment protocol that minimizes stress on the maxillary bone and teeth. Materials and Methods: On the virtual models obtained from the cone beam computed tomography of a patient, two different incisions (the pterygomaxillary junction is separated and not separated) were made and combined using three different orthodontic appliances (tooth, bone, and hybrid assisted). Then, stresses over the maxillary bone and maxillary teeth were calculated by FEM. Results: Our results showed that when the pterygomaxillary plates were separated, fewer stresses were observed on the bone and teeth. Although hybrid-supported appliances created less stress on the teeth than tooth-supported appliances and no difference was found between bone-supported appliances, it was found that hybrid-supported appliances created less stress on the bone than the other appliances. Conclusions: The separation of the pterygomaxillary junction in the SARME operation and the use of a bone-supported or hybrid-supported appliance would place less stress on the bone and teeth.Öğe Kinematics, kinetics, and forces of the knee joint during walking(Elsevier, 2024) Karabulut, Derya; Arslan, Yunus ZiyaMotion analysis is a valuable tool to monitor the kinematics and kinetics of body parts quantitatively and the decision-making process in clinical implementations. In gait analysis systems, temporospatial parameters, joint angles, joint moments, and ground reaction forces can be recorded. However, some other biomechanical parameters such as muscle forces, joint reaction forces, and muscle-tendon unit length change cannot be noninvasively recorded in gait analysis systems. Accordingly, musculoskeletal modeling and simulation tools are very widely used to obtain such biomechanical parameters. In this chapter, we presented the details about kinematics and kinetics of the knee joint during a healthy gait. In this context, joint angles, joint moments, muscle forces, and joint reaction forces were provided. Furthermore, some special cases seen in various musculoskeletal disorders that affect the ability of gait are also investigated.Öğe Machine learning-based prediction of joint moments based on kinematics in patients with cerebral palsy(Journal of Biomechanics, 2023) Arslan, Yunus Ziya; Özateş, Mustafa Erkam; Karabulut, Derya; Wolf, Sebastian Immanuel; Salami, FiroozJoint moments during gait provide valuable information for clinical decision-making in patients with cerebral palsy (CP). Joint moments are calculated based on ground reaction forces (GRF) using inverse dynamics models. Obtaining GRF from patients with CP is challenging. Typically developed (TD) individuals’ joint moments were predicted from joint angles using machine learning, but no such study has been conducted on patients with CP. Accordingly, we aimed to predict the dorsi-plantar flexion, knee flexion–extension, hip flexion–extension, and hip adduction-abduction moments based on the trunk, pelvis, hip, knee, and ankle kinematics during gait in patients with CP and TD individuals using one-dimensional convolutional neural networks (CNN). The anonymized retrospective gait data of 329 TD (26 years ± 14, mass: 70 kg ± 15, height: 167 cm ± 89) and 917 CP (17 years ± 9, mass:47 kg ± 19, height:153 cm ± 36) individuals were evaluated and after applying inclusion–exclusion criteria, 132 TD and 622 CP patients with spastic diplegia were selected. We trained specific CNN models and evaluated their performance using isolated test subject groups based on normalized root mean square error (nRMSE) and Pearson correlation coefficient (PCC). Joint moments were predicted with nRMSE between 18.02% and 13.58% for the CP and between 12.55% and 8.58% for the TD groups, whereas with PCC between 0.85 and 0.93 for the CP and between 0.94 and 0.98 for the TD groups. Machine learning-based joint moment prediction from kinematics could replace conventional moment calculation in CP patients in the future, but the current level of prediction errors restricts its use for clinical decision-making today.Öğe Patellar tendon advancement for the treatment of crouch gait in patients with cerebral palsy(2023) Karabulut, Derya; Arslan, Yunus Ziya; Salami, Firooz; Wolf, Sebastian Immanuel; Goetze, MarcoCrouch gait is a frequent gait pathology in children with cerebral palsy (CP). Patellar tendon advancement (PTA) is a typical surgery among single-event multilevel surgery (SEMLS) for the treatment of crouch gait and performed to enhance the knee joint kinematics and kinetics Patella position had a considerable effect on the torque-producing capacity of the quadriceps and hence, patellar height is a typical metric to assess the influence of PTA on knee function. Patellar height can be assessed by using several radiographic imaging methods. How ever, in the literature, there is no consensus on objective quantification of the patellar height In our study, we aimed to i) objectively quantify the patella position using X-ray data and musculoskeletal modeling and ii) monitor the effect of PTA in combination with SEMLS on the knee kinematics of patients with CP and crouch gait.Öğe Sensitivity of model-predicted muscle forces of patients with cerebral palsy to variations in muscle-tendon parameters(World Scientific Publishing, 2021) Arslan, Yunus Ziya; Karabulut, DeryaComputational musculoskeletal modeling and simulation platforms are efficient tools to gain insight into the muscular coordination of patients with motor disabilities such as cerebral palsy (CP). Muscle force predictions from simulation programs are influenced by the architectural and contractile properties of muscle-tendon units. In this study, we aimed to evaluate the sensitivity of major lower limb muscle forces in patients with CP to changes in muscle-tendon parameters. Open-access datasets of children with CP (n=8) and healthy children (n=8) were considered. Monte Carlo analysis was executed to specify how sensitive the muscle forces to perturbations between +10% and ?10% of the nominal value of the maximum isometric muscle force, optimal muscle fiber length, muscle pennation angle, tendon slack length, and maximum contraction velocity of muscle. The sensitivity analysis revealed that muscle forces of CP patients and healthy individuals were most sensitive to perturbations in the tendon slack length (p<0.05), while forces of CP patients were more sensitive to tendon slack length when compared to the healthy group (p<0.05). Muscle forces of patients and healthy individuals were insensitive to the other four parameters (p>0.05), except for the gracilis and sartorius muscles in which the proportion of optimal muscle fiber length to tendon slack length is higher than 1; forces of these two muscles were also sensitive to the optimal muscle fiber length. The results of this study are expected to contribute to our understanding of which parameters should be personalized when conducting musculoskeletal modeling and simulation of patients with CP.Öğe The effect of papaverine on tendon healing and adhesion in rats following Achilles tendon repair(2024) Arslan, Yunus Ziya; Can, Erdem; Dincel, Yaşar Mahsut; Karabulut, Derya; Karabağ, SevilThe Achilles tendon, recognized as the strongest tendon in the human body, plays a pivotal role in transferring the forces generated by the gastrocnemius and soleus muscles to the calcaneus. This complex mechanism is essential for fundamental activities such as walking, jumping, and running.[1,2] Notably, the incidence of acute tendon injuries tends to rise within the age range of 30 to 40 years, predominantly affecting male individuals. These injuries are frequently linked to recreational sports, such as ball games and racket sports, that involve rapid acceleration and jumping.Öğe The effect of PEEK-Rod fixation systems on finite element lumbar spine model(Avrupa Bilim Ve Teknoloji Dergisi, 2022) Arslan, Yunus Ziya; Akıncı, Saliha Zeyneb; Yaman, Onur; Sürmen, Hasan Kemal; Karabulut, DeryaOrthopedic fixation devices have been employed in the treatment of spinal diseases. Special fixation devices have been developed to decrease the effect of spinal injuries and deformities and have been used to decrease the neurologic back pain of the patients. In this study, the finite element spine model of an adolescent idiopathic scoliotic patient was constructed. The titanium spinal implant system and the system of polyetheretherketone (PEEK) were compared regarding their stress distributions. The finite element lumbar spine model from L2 to L5 vertebra was obtained from computed tomography scan data. The three-dimensional spine model consisted of four lumbar vertebrae, three intervertebral discs, six facet joints, and the corresponding ligaments. Loading and boundary conditions were applied to the L2-L5 lumbar model. According to the subjected loads and bending moments on the model, stress distributions were evaluated especially on the intervertebral discs, and the screw-rod implant systems both for the titanium and the PEEK-based fixation systems. The disc structures were also analyzed for the effects of adjacent segment disease, which has been reported as a post-operative effect of fusion surgeries. Ansys software was used for the simulation processes of the models without the implant system and the models with different fixation systems. Comparative investigation between different fixation systems showed that the stress distribution values were decreased with the PEEK-based fixation system. Moreover, lower total deformation and equivalent stress values were recorded with the PEEK-based fixation system, especially on L3-L4 and L4-L5 intervertebral discs. Furthermore, both spinal implant systems allowed to decrease the overall loading stress on the whole spine models. And it was concluded that the PEEK-based spinal implant system was considerably reduced the load on the discs and ligaments, and also appeared as a better option in stress reduction and load sharing when compared to the titanium spinal implant system.Öğe The impact of patellar tendon advancement on knee joint moment and muscle forces in patients with cerebral palsy(MDPI-Multidisciplinary Digital Publishing Institute, 2021) Karabulut, Derya; Arslan, Yunus Ziya; Götze, Marco; Wolf, SebastianBackground: Patellar tendon advancement (PTA) is performed for the treatment of crouch gait in patients with cerebral palsy (CP). In this study, we aimed to determine the influence of PTA in the context of single-event multilevel surgery (SEMLS) on knee joint moment and muscle forces through musculoskeletal modeling; Methods: Gait data of children with CP and crouch gait were retrospectively analyzed. Patients were included if they had a SEMLS with a PTA (PTA group, n = 18) and a SEMLS without a PTA (NoPTA group, n = 18). A musculoskeletal model was used to calculate the pre- and postoperative knee joint moments and muscle forces; Results: Knee extensor moment increased in the PTA group postoperatively (p = 0.016), but there was no statistically significant change in the NoPTA group (p > 0.05). The quadriceps muscle forces increased for the PTA group (p = 0.034), while there was no difference in the NoPTA group (p > 0.05). The hamstring muscle forces increased in the PTA group (p = 0.039), while there was no difference in the NoPTA group (p > 0.05); Conclusions: PTA was found to be an effective surgery for the treatment of crouch gait. It contributes to improving knee extensor moment, decreasing knee flexor moment, and enhancing the quadriceps and hamstring muscle forces postoperatively.Öğe The prolonged effect of Kinesio Taping on joint torque and muscle activity(Taylor & Francis Ltd, 2022) Kulli, Hilal Denizoglu; Karabulut, Derya; Arslan, Yunus ZiyaPurposeAlthough Kinesio Taping has been extensively used, evidence about the effect of Kinesio Taping is still insufficient. The aim is to determine the effect of Kinesio Taping on elbow joint torque and muscle activity in time and frequency domains.Materials and MethodsThirty-eight healthy subjects were (27 females and 11 males) randomly divided into control and Kinesio Taping groups. Kinesio Taping was applied over biceps brachii muscle in Kinesio Taping group, whereas no taping was applied to control group. Maximum elbow joint torque and electromyography activity in time and frequency domains were assessed during maximum isometric contraction of biceps brachii muscle at baseline, after 10 min, 30 min, and 24 h. Repeated measure ANOVA and mixed ANOVA tests were used for in-group and between-group comparisons, respectively.ResultsElbow joint torques among four assessment sessions were statistically altered in Kinesio Taping group and greater in Kinesio Taping group than in control group (F(3,57)= 3.317, p = 0.026, eta p2 = 0.149; F(3,108)=3.325, p = 0.022, eta p2 = 0.085; respectively). No difference was found in time domain muscle activity among assessment sessions in each group and comparison of groups (p > 0.05). Low-gamma band activity was changed among assessment sessions in Kinesio Taping group (F(3,57)= 6.946, p < 0.001, eta p2 = 0.268) while group x time interaction was not determined.ConclusionsKinesio Taping may influence joint torque of elbow more than without Kinesio Taping condition in 24th hour but the interpretation of this effect as a muscle strength enhancement compared with baseline can be arguable. Even if Kinesio Taping could not affect muscle activity in time domain, low-gamma band activity which is closely related to somatosensorial input may reach highest magnitude 24 h after Kinesio Taping.
