Purpose: To design a new type of screw for minimally invasive atlantoaxial anterior transarticular screw (AATS) fixation with a diameter that is significantly thicker than that of traditional screws, threaded structures at both ends, and a porous metal structure in the middle. The use of a porous metal structure can effectively promote bone fusion and compensate for the disadvantages of traditional AATSs in terms of insufficient fixation strength and difficulty of bone fusion. The biomechanical stability of this screw was verified through finite element analysis. This instrument may provide a new surgical option for the treatment of atlantoaxial disorders.Methods: According to the surgical procedure, the new type of AATS was placed in a three-dimensional atlantoaxial model to determine the setting of relevant parameters such as the diameter, length, and thread to porous metal ratio of the structure. According to the results of measurement,the feasibility and safety of the new AATS was verified, and a representative finite element model of the upper cervical vertebrae was chosen to establish, and the validity of the model was verified. Then, finite element-based biomechanical analysis was performed using three models, i.e., atlantoaxial posterior pedicle screw fixation, traditional atlantoaxial AATS fixation, and atlantoaxial AATS fixation with the new type of screw, and the biomechanical effectiveness of the novel AATS was verified.Results: By measuring the atlantoaxial parameters, the atlantoaxial CT data of the representative 30-year-old normal adult male were selected to create a personalized 3D printing AATS screw. In this case,the design parameters of the new screw were determined as follows: diameter, 6mm; length of the head thread structure, 10 mm; length of the middle porous metal structure, 8 mm (a middle porous structure containing an annular cylinder );length of the tail thread structure, 8 mm; and total length,26 mm. Apply the same load conditions to the atlantoaxial complex along different directions in the established finite element models of the three types of atlantoaxial fusion modes, the immediate stability of the new AATS is similar with Atlantoaxial posterior pedicle screw fixation.They are both superior to traditional atlantoaxial anterior screw fixation.The maximum local stress on the screw head in the atlantoaxial anterior surgery were less than those of traditional atlantoaxial anterior surgery.Conclusions: By measuring relevant atlantoaxial data, we found that screws with a larger diameter can be used in AATS surgery, and the new AATS can make full use of the atlantoaxial lateral mass space and increase the stability of fixation. The finite element analysis and verification revealed that the biomechanical stability of the new AATS was superior to the AATS used in traditional atlantoaxial AATS fixation. The porous metal structure of the new AATS may promote fusion between atlantoaxial joints and allow more effective bone fusion in the minimally invasive anterior approach surgery.
Purpose: To design a new type of screw for minimally invasive atlantoaxial anterior transarticular screw (AATS) fixation with a diameter that is significantly thicker than that of traditional screws, threaded structures at both ends, and a porous metal structure in the middle. The use of a porous metal structure can effectively promote bone fusion and compensate for the disadvantages of traditional AATSs in terms of insufficient fixation strength and difficulty of bone fusion. The biomechanical stability of this screw was verified through finite element analysis. This instrument may provide a new surgical option for the treatment of atlantoaxial disorders.Methods: According to the surgical procedure, the new type of AATS was placed in a three-dimensional atlantoaxial model to determine the setting of relevant parameters such as the diameter, length, and thread to porous metal ratio of the structure. According to the results of measurement,the feasibility and safety of the new AATS was verified, and a representative finite element model of the upper cervical vertebrae was chosen to establish, and the validity of the model was verified. Then, finite element-based biomechanical analysis was performed using three models, i.e., atlantoaxial posterior pedicle screw fixation, traditional atlantoaxial AATS fixation, and atlantoaxial AATS fixation with the new type of screw, and the biomechanical effectiveness of the novel AATS was verified.Results: By measuring the atlantoaxial parameters, the atlantoaxial CT data of the representative 30-year-old normal adult male were selected to create a personalized 3D printing AATS screw. In this case,the design parameters of the new screw were determined as follows: diameter, 6mm; length of the head thread structure, 10 mm; length of the middle porous metal structure, 8 mm (a middle porous structure containing an annular cylinder );length of the tail thread structure, 8 mm; and total length,26 mm. Apply the same load conditions to the atlantoaxial complex along different directions in the established finite element models of the three types of atlantoaxial fusion modes, the immediate stability of the new AATS is similar with Atlantoaxial posterior pedicle screw fixation.They are both superior to traditional atlantoaxial anterior screw fixation.The maximum local stress on the screw head in the atlantoaxial anterior surgery were less than those of traditional atlantoaxial anterior surgery.Conclusions: By measuring relevant atlantoaxial data, we found that screws with a larger diameter can be used in AATS surgery, and the new AATS can make full use of the atlantoaxial lateral mass space and increase the stability of fixation. The finite element analysis and verification revealed that the biomechanical stability of the new AATS was superior to the AATS used in traditional atlantoaxial AATS fixation. The porous metal structure of the new AATS may promote fusion between atlantoaxial joints and allow more effective bone fusion in the minimally invasive anterior approach surgery.
Purpose: A modified local transposition flap surgery was performed for fingertip injuries. Given the shape of the flap turnover resembling a parallelogram, we called it a parallelogram flap. This transposition flap surgery allows a more significant transfer distance with good outcomes.Method: The study collected patients who underwent parallelogram transposition flaps to repair fingertip defects from 2017 to 2020. 32 cases (32 fingers) were included in our study, including 20 males and 12 females, aged 17 to 60 years, with an average age of 36 years. The causes of injury were crush injury in 13 cases, punch injury in 11 cases and sharp cutting injury in 8 cases. There were 6 cases in thumbs, 6 cases in index fingers, 14 cases in middle fingers, 4 cases in ring fingers and 2 cases in little fingers. The area of fingertip defects was 1.2 cm × 2~3 cm × 4 cm, with bone exposure. The interval between the injury and operation was 5.78 h (the mean value was 4.7-8.4 h). All operations were performed by one surgical team, and the average operation time was 31.2 min.Record The length and width of the finger,two-point discrimination(2PD),Total Active Movement (TAM)and the MHQ (Michigan Hand Questionnaire) of the injured fingers to evaluate the therapeutic effect.Results: all our parallelogram flaps had survived postoperatively.,At last follow-up,There was no difference between the length and width of the reconstructed finger and that of the healthy side(P>0.05). The qualification rate of the static 2PD of the flaps were 84.37% .The qualification rate of the TAM of injured figures were 100% . Evaluation of the MHQ subscale performance showed that the score of the overall hand function is 93.71, activities of daily living is 95.22, work performance is 94.23,pain score is 4.34 , aesthetics is 92.15 and satisfaction score is 92.45.All of these were perform well.Conclusion: This transposition flap surgery allows a more significant transfer distance with good outcomes.
Purpose : To design a new type of screw for minimally invasive atlantoaxial anterior transarticular screw (AATS) fixation with a diameter that is significantly thicker than that of traditional screws, threaded structures at both ends, and a porous metal structure in the middle. The use of a porous metal structure can effectively promote bone fusion and compensate for the disadvantages of traditional AATSs in terms of insufficient fixation strength and difficulty of bone fusion. The biomechanical stability of this screw was verified through finite element analysis. This instrument may provide a new surgical option for the treatment of atlantoaxial disorders. Methods: According to the surgical procedure, the new type of AATS was placed in a three-dimensional atlantoaxial model to determine the setting of relevant parameters such as the diameter, length, and thread to porous metal ratio of the structure. A finite element model of the upper cervical vertebrae was established, and the validity of the model was verified. Then, finite element-based biomechanical analysis was performed using three models, i.e., atlantoaxial posterior pedicle screw fixation, traditional atlantoaxial AATS fixation, and atlantoaxial AATS fixation with the new type of screw, and the biomechanical effectiveness of the novel AATS was verified. Results: By measuring the atlantoaxial parameters, the design parameters of the new screw were determined as follows: diameter, 6-7 mm; length of the head thread structure, 8-10 mm; length of the middle porous metal structure, 8 mm (a middle porous structure containing an annular cylinder with an outer diameter of 3 mm and an inner diameter of 1 mm, which facilitated the placement of the guide wire); length of the tail thread structure, 6-8 mm; and total length, 22-26 mm.Apply the same load conditions to the atlantoaxial complex along different directions in the established finite element models of the three types of atlantoaxial fusion modes, the immediate stability of the new AATS is similar with Atlantoaxial posterior pedicle screw fixation.They are both superior to traditional atlantoaxial anterior screw fixation.The maximum local stress on the screw head in the atlantoaxial anterior surgery were less than those of traditional atlantoaxial anterior surgery. Conclusions : By measuring relevant atlantoaxial data, we found that screws with a larger diameter can be used in AATS surgery, and the new AATS can make full use of the atlantoaxial lateral mass space and increase the stability of fixation. The finite element analysis and verification revealed that the biomechanical stability of the new AATS was superior to the AATS used in traditional atlantoaxial AATS fixation. The porous metal structure of the new AATS may promote fusion between atlantoaxial joints and allow more effective bone fusion in the minimally invasive anterior approach surgery.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.