ABSTRACT
PURPOSE: While Clavicle hook plates have demonstrated favorable results regarding bone and shoulder function, their design can potentially lead to complications due to pressure concentration at the plate's tip. This study aims to investigate the impact of different hook implantation angles on the contact surface area between the hook plate and acromion, with the goal of minimizing mismatch and maximizing contact surface area. METHODS: Twenty soft shoulder cadavers were included in the study, and the contact surface area of the hook plate was measured in different positions based on the hook implantation angle. RESULTS: The results showed variations in compatibility, width, and length of the contact surface area depending on the hook implantation angle and the medial or lateral row placement. The lateral row generally demonstrated superior compatibility (84.0% vs 46.67%, p-value < 0.001), with a broader contact area (3.55 ± 0.08 mm vs 3.09 ± 0.10 mm, p-value = 0.004) and a longer contact area (7.36 ± 0.19 mm vs 5.10 ± 0.23 mm, p-value < 0.001) at specific angles. A detailed analysis of the lateral position revealed that the zero angle of implantation resulted in the greatest contact surface area, measuring 3.91 ± 0.70 mm in width (p value = 0.083) and 8.85 ± 1.24 mm in length (p value < 0.001). CONCLUSION: Placing the hook laterally and at the zero position according to the hook implantation angle can maximize contact surface area, may reduce stress concentration, and minimize complications in hook plate fixation. Further research and consideration of anatomical variations are warranted to refine the placement technique and enhance patient outcomes. LEVEL OF EVIDENCE: Level V evidence.
ABSTRACT
BACKGROUND: Hip tumors often require tumor-type artificial joint replacement. The selection of the prosthesis stem (hip tumor prosthesis stem) implantation angle during the operation is important to prevent the complication of postoperative prosthesis dislocation. The aim of this study was to evaluate the role of a nickel-titanium (Ni-Ti) shape memory alloy embracing fixator in determination of the implantation angle of a hip tumor prosthesis stem and analyze its efficacy. METHODS: 36 patients with proximal femur tumor were treated with extended tumor resection and prosthetic replacement. 14 patients received prosthetic replacements with the embracing fixators fixing between the junction of the prosthesis stem and the femur temporarily, while the other 22 patients received the same replacements but without the fixators. The two groups were compared regarding occurrence of complications, limb function, and active hip range of motion (ROM). RESULTS: There was no case of hip dislocation in the group that received prosthetic replacements with the use of embracing fixators. Occurrence of deep infection had no difference between the two groups. However, better limb function and higher active (ROM) on abduction or flexion were observed in the group using embracing fixators. CONCLUSION: Ni-Ti shape memory alloy embracing fixator plays a key role in assisting the accurate implantation angle of the prosthesis stem in prosthetic replacement. The prosthesis stem can be adjusted to the optimal angle with the help of the embracing fixator. Patients have a lower risk of dislocation, better limb function, and higher active hip ROM.
ABSTRACT
Objective@#Conebeam CT (CBCT) was used to measure the palatine between the maxillary first and second molars. The proximal and distal palatal widths of the maxillary first and second molar and the palatal mucosal thickness and bone tissue thickness when microscrew implant anchorage nail were implanted at different angles provided a reference for the clinical selection of microscrew implant placement.@* Methods@#The image data of 90 adult patients were selected as the research object, and the jaw bone was reconstructed by scanning. In maxillary palatine, selection of distances at 12 mm, 14 mm, 16 mm, and 18 mm from the palatal apex of maxillary first molar between the maxillary first and second molar were used as measurement, measured the proximal and distal palatal widths of maxillary first and second molar and the palatal mucosal thickness and bone tissue thickness when microscrew implant anchorage nails were implanted at 30 °, 45 °, 60 °, and 90 °. SPSS 26.0 software was used for one-way ANOVA and LSD pair comparison. @*Results@#The larger the angle of the microscrew implant anchorage nail was, the smaller the proximal and distal medial widths between the maxillary first and second molar, and the difference was statistically significant (P < 0.05). Compared with the 90° direction, the proximal and distal medial widths of the microscrew implant anchorage nail were larger in the 60° direction. The greater the angle of implantation, the smaller the mucosal thickness and the greater the bone tissue thickness, and the results showed a significant difference (P < 0.001). Compared with the direction of 30° and 45°, the mucosal thickness at the direction of 60° was smaller, and the bone tissue thickness was larger. The higher the position of the microscrew implant anchorage nail, the greater the width of the proximal and distal medial, and the difference was statistically significant (P < 0.05). Compared with the positions 12 and 14 mm from the palatal tip, the proximal and distal medial widths of the microscrew implant anchorage nail were larger. The higher the implant position was, the greater the mucosal thickness and the smaller the bone tissue thickness. The results showed a significant difference (P < 0.001). Compared with the position of 18 mm from the palatal tip of the maxillary first molar, the mucosal thickness was smaller and the bone tissue thickness was larger.@*Conclusion@#It is most appropriate to implant microscrew implant anchorage nail at least 10 mm in length in the direction of 60° at the palatal apex 16 mm from the maxillary first molar in palatine between the first and second molar.
ABSTRACT
The orthodontic miniscrew is driven into bone in a clockwise direction. Counter-clockwise rotational force applied to the implanted miniscrew can degrade the stability. The purpose of this three-dimensional finite element study was to figure out the effect of shifting the miniscrew head hole position from the long axis. Two miniscrew models were developed, one with the head hole at the long axis and the other with an eccentric hole position. One degree of counter-clockwise rotation was applied to both groups, and the maximum Von-Mises stress and moment was measured under various wire insertion angles from -60° to +60°. All Von-Mises stress and moments increased with an increase in rotational angle or wire insertion angle. The increasing slope of moment in the eccentric hole group was significantly higher than that in the centric hole group. Although the maximum Von-Mises stress was higher in the eccentric hole group, the distribution of stress was not very different from the centric hole group. As the positive wire insertion angles generated a higher moment under a counter-clockwise rotational force, it is recommended to place the head hole considering the implanting direction of the miniscrew. Clinically, multidirectional and higher forces can be applied to the miniscrew with an eccentric head hole position.
Subject(s)
Orthodontic Anchorage Procedures , Bone Screws , Finite Element Analysis , Mechanical Phenomena , Stress, MechanicalABSTRACT
Cone Beam Computed Tomography (CBCT) measurement of cortical bone thickness and implantation angle in the maxillary posterior region was used to provide reference for the safety of Micro-Implanted-Anchorage (MIA) implantation in skeletal class II malocclusion. Twenty samples of CBCT images were collected from orthodontics patients (ages, 12-40 years) in Shanxi Medical University Stomatological Hospital, the thickness of cortical bone was measured at 45°, 60° and 90° from the alveolar crest, being at 4 mm, 6 mm and 8 mm, respectively. SPSS17.0 statistical software was used to analyze the data, and the one-way ANOVA and LSD method were compared. There was a significant difference in the thickness of the cortical bone obtained by implanting MIA at the same height of different angle (P≤0.05). The greater the inclination angle of the implanted MIA, the thicker the cortical bone. Also, the higher the implant site, the thicker the cortical bone thickness. Finally, the greater the thickness of the cortical bone in the maxillary posterior region of skeletal class II malocclusion, the greater the thickness of the cortical bone. At the same implantation height, implanted MIA with a tilt angle of 45º to 60º, 90º to obtain the best cortical bone thickness.
La medición del grosor del hueso cortical y del ángulo de implantación en la región posterior del maxilar por tomografía computarizada de haz cónico (TCHC) se utilizó para proporcionar una referencia para la implantación y el anclaje seguros de un Micro-Implante de Anclaje (MIA) en la maloclusión de clase esquelética tipo II. Veinte muestras de imágenes de TCHC fueron obtenidas de pacientes de ortodoncia (12-40 años) en el Hospital Estomatológico de la Universidad Médica de Shanxi. Se midió el grosor del hueso cortical a 45°, 60° y 90° de la cresta alveolar, encontrándose a 4 mm, 6 mm y 8 mm, respectivamente. Se utilizó el software estadístico SPSS 17.0 para analizar los datos, y se compararon con los métodos ANOVA y LSD de un factor. Hubo una diferencia significativa en el grosor del hueso cortical obtenido al implantar el MIA a la misma altura en diferentes ángulos (P <0,05). Cuanto mayor es el ángulo de inclinación del MIA implantado, más grueso es el hueso cortical. También, cuanto más alto es el sitio del implante, más grueso es el grosor del hueso cortical. Finalmente, cuanto mayor sea el grosor del hueso cortical en la región posterior del maxilar, en la maloclusión de clase esquelética tipo II, mayor será el grosor del hueso cortical.
Subject(s)
Humans , Male , Female , Adolescent , Adult , Orthodontic Anchorage Procedures , Cortical Bone/anatomy & histology , Cortical Bone/diagnostic imaging , Malocclusion, Angle Class II , Cone-Beam Computed TomographyABSTRACT
BACKGROUND: Multi-detector computed tomography (MDCT) predicted orthogonal projection angles have been introduced to guide valve deployment during transcatheter aortic valve replacement (TAVR). Our aim was to investigate the accuracy of MDCT prediction methods versus actual angiographic deployment angles. METHODS: Retrospective analysis of 2 currently used MDCT methods: manual multiplanar reformations (MR) and the semiautomatic optimal angle graph (OAG). Paired analysis was used to compare the 2-dimensional distributions and means. RESULTS: We included 101 patients with a mean (±SD) age of 81⯱â¯9 years. The MR and OAG methods were used in 46 and 55 patients, respectively. A ≥5% change from the predicted MDCT range in left anterior oblique/right anterior oblique (LAO/RAO) and the cranial/caudal (CRA/CAU) angle occurred in 42% and 58% of patients, respectively. The mean predicted versus actual deployment angles were significantly different (CRA/CAU: -2.6⯱â¯11.5 vs. -7.6⯱â¯10.7, pâ¯<â¯0.001; RAO/LAO 8.1⯱â¯10.9 vs. 9.5⯱â¯10.6, pâ¯=â¯0.048; respectively). The MR method resulted in a more accurate CRA/CAU angle (CRA/CAU: -4.6⯱â¯11.1 vs. -6.5⯱â¯11.8, pâ¯=â¯0.139; RAO/LAO 7.4⯱â¯11.2 vs. 10.4⯱â¯11.2, pâ¯=â¯0.008; respectively), whereas the use of the OAG resulted in a more accurate RAO/LAO angle (CRA/CAU: -0.9⯱â¯10.8 vs. -9±11.2, pâ¯<â¯0.001; RAO/LAO 9.05⯱â¯10.6 vs. 8.5⯱â¯9.9, pâ¯=â¯0.458; respectively). For the entire cohort, the 2-dimensional distributions and means of the predicted versus the actual angles were significantly different from each other (pâ¯<â¯0.001). We repeated our analysis using both MDCT methods and demonstrated similar results with each method. CONCLUSIONS: Currently used MDCT methods for TAVR implantation angles are significantly modified before actual valve deployment. Thus, further refinement of these prediction methods is required.
