Improving the accuracy of patient positioning for long-leg radiographs using a Taylor Spatial Frame mounted rotation rod

Ahrend, Marc-Daniel; Finger, Felix; Grünwald, Leonard; Keller, Gabriel; Baumgartner, H.

doi:10.1007/s00402-020-03460-0

Cited by 21 publications

(34 citation statements)

References 22 publications

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“…In patients with a circular fixator, limbs are positioned more in external rotation than without an external fixator [33]. To achieve higher reliability and to reduce malpositioning of the limb on LLR, a rod can be placed at the reference ring of the external fixator to better control limb positioning [34]. Moreover, the use of the light source and the laser from the X-ray can enhance the quality of radiographs [13,35].…”

Section: Discussionmentioning

confidence: 99%

Distance from the magnification device contributes to differences in lower leg length measured in patients with TSF correction

Ahrend

Rühle

Springer³

et al. 2021

Arch Orthop Trauma Surg

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Introduction In absence of deformity or injury of the contralateral leg, the contralateral leg length is used to plan limb lengthening. Length variability on long-leg weight-bearing radiographs (LLR) can lead to inaccurate deformity correction. The aim of the study was to (1) examine the variability of the measured limb length on LLR and (2) to examine the influence of the position of the magnification device. Materials and methods The limb lengths of 38 patients during deformity correction with a taylor-spatial-frame were measured retrospectively on 7.3 ± 2.6 (4–13) LLR per patient. The measured length of the untreated limb between LLR were used to determine length variability between LLR in each patient. To answer the secondary aim, we took LLR from a 90 cm validation distance. A magnification device was placed in different positions: at the middle of the 90 cm distance (z-position), 5 cm anterior and 5 cm posterior from the z-position, at the bottom and top of the validation distance as well as 5 cm medial and 15 cm lateral from the z-position. Results The measured length variability ranged within a patient from 10 to 50 mm. 76% of patients had a measured limb length difference of ≥ 2 cm between taken LLR. Compared to length measurement of the 90 cm test object with the magnification device in the z-position (90.1 cm), positioning the device 5 cm anterior led to smaller (88.6 cm) and 5 cm posterior led to larger measurements (91.7 cm). The measured length with the magnification device at the bottom, top, medial or lateral (90.4; 89.9; 90.2; 89.8 cm) to the object differed not relevantly. Conclusions High variability of limb length between different LLR within one patient was observed. This can result from different positions of the magnification device in the sagittal plane. These small changes in positioning the device should be avoided to achieve accurate deformity correction and bone lengthening. This should be considered for all length and size measurements on radiographs.

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Section: Discussionmentioning

confidence: 99%

Distance from the magnification device contributes to differences in lower leg length measured in patients with TSF correction

Ahrend

Rühle

Springer³

et al. 2021

Arch Orthop Trauma Surg

Self Cite

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“…The TSF system required orthogonal AP and lateral X-rays when defining the deformity parameters [27][28][29][30] , which was conducted subjectively by radiologists and it is impossible to determine the orthogonality of the X-rays in clinical practice [31] . Additionally, Xrays may need to be taken repeatedly because of manual measurement errors.…”

Section: Discussionmentioning

confidence: 99%

“…Kucukkaya et al [25] calculated the mounting parameters using the tomographic images in CT, they demonstrated its advantages, especially in deformities with a rotational deformity. Ahrend et al [30] used a Taylor spatial frame mounted rotation rod to improve the accuracy of patient positioning for long-leg. They claimed that the variability of rotation on radiographs was lower with the rotation rod.…”

Section: Discussionmentioning

confidence: 99%

Application of elliptic registration and three-dimensional reconstruction in the postoperative measurement of Taylor spatial frame parameters

Liu

Yushan

Liu

et al. 2020

Injury

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Background: The Taylor spatial frame offered the ability of simultaneous correction of the multidirectional deformities without the need to change the frame, and it was widely used for limb lengthening, deformity correction, and fracture reduction in recent years. There are still some inherent limitations that can affect the accuracy of correction, especially for the measurement of the mounting and rotational parameters. The purpose of our study was to propose some more precise postoperative measurement of Taylor spatial frame (TSF) parameters by application of elliptic registration and three-dimensional reconstruction. Methods: This retrospectively study included 28 trauma patients who suffered tibial fracture treated by the TSF at our institution from January 2016 to January 2018, including 25 males and 3 females with a mean age of 43 years (range 14-70 years). We conducted standard full-length anteroposterior and lateral X-rays of the injured extremity and the computed tomographic scans of the bilateral extremities after the operation. Elliptic registration and 3D reconstruction were used to calculate the parameters by two types of software Mimics and CorelDRAW. Correction of the deformity was conducted by adjusting the struts of the TSF according to the electronic prescription. The standard anteroposterior and lateral X-rays after correction were taken to evaluate the effectiveness. Results: All patients acquired functional reduction, which was evaluated by digital radiography. The mean coronal plane translation(1.9 ±2.2 mm), coronal plane angulation(1.2 ±1.0 °), sagittal plane translation(2.7 ±2.1 mm), and sagittal plane angulation(1.2 ±1.0 °) after correction were all less than those(5.5 ±4.6 mm, 4.9 ±3.9 °, 4.7 ±4.0 mm, 2.7 ±2.3 °) before correction. Conclusions: The TSF system can correct the 6-axis deformities simultaneously with the accurate parameters. Elliptic registration and three-dimensional reconstruction are alternative methods to precisely measure the parameters needed by the TSF system, especially for the mounting and rotational parameters of unusually complex cases.

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“…Gantsoudes et al 36 declared it is easily reproducible in the operating room and allows for accurate measurement of the mounting parameters when conducted intraoperative measurement. Ahrend et al 37 used rotation rod to control limb rotation before taking radiographs and enhance the standard radiographic procedure, they concluded that the variability of rotation on radiographs was lower with the rotation rod, and more reproducible and better comparable radiographs can be conducted. However, these techniques are all dependent on the measurements in 2D planes.…”

Section: Discussionmentioning

confidence: 99%

Long Bone Fracture Reduction and Deformity Correction Using the Hexapod External Fixator With a New Method: a Feasible Study and Preliminary Results

Liu

et al. 2020

Preprint

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Background: The hexapod external fixator (HEF), such as the Taylor spatial frame (TSF), offering the ability of simultaneous correction of the multidirectional deformities without frame modification, whereas there are so many parameters for surgeons to measure and subjective errors will occur inevitably. The purpose of this study was to evaluate the effectiveness of a new method based on computer-assisted three-dimensional (3D) reconstruction and hexapod external fixator for long bone fracture reduction and deformity correction without calculating the parameters needed by the computer program.Methods: This retrospective study consists of 25 patients with high-energy tibial diaphyseal fractures treated by the HEF at our institution from January 2016 to June 2018, including 22 males and 3 females with a mean age of 42 years (range 14-63 years). Hexapod external fixator treatments were performed due to primary and definitive management of multiplanar posttraumatic deformity and/or severe soft-tissue damage that were not suitable for internal fixation in the tibia. Computer-assisted 3D reconstruction and trajectory planning of the reduction by Mimics were applied to perform virtual fracture reduction and deformity correction. The electronic prescription derived from the length changes of the six struts were calculated by SolidWorks. Fracture reduction was conducted by adjusting the lengths of the six struts according to the electronic prescription. The standard anteroposterior (AP) and lateral X-rays after reduction were taken to evaluate the effectiveness.Results: All patients acquired excellent functional reduction (most cases achieved anatomical reduction) in our study. The mean coronal plane translation (1.0±1.1 mm), coronal plane angulation (0.8±1.2°), sagittal plane translation (0.8±1.0 mm) and sagittal plane angulation (0.3±0.8°) after correction were all less than those (6.1±4.9 mm, 5.2±3.2°, 4.2±3.5 mm, 4.0±2.5°) before correction (P<0.05).Conclusion: The computer-assisted three-dimensional reconstruction and hexapod external fixator-based method allows surgeons to conduct long bone fracture reduction and deformity correction without calculating the parameters needed by the computer program. Considering the radiologic exposure, this method is suggested to apply in those unusually complex cases with extensive soft tissue damage and internal fixation is impossible or inadvisable.

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Improving the accuracy of patient positioning for long-leg radiographs using a Taylor Spatial Frame mounted rotation rod

Cited by 21 publications

References 22 publications

Distance from the magnification device contributes to differences in lower leg length measured in patients with TSF correction

Distance from the magnification device contributes to differences in lower leg length measured in patients with TSF correction

Application of elliptic registration and three-dimensional reconstruction in the postoperative measurement of Taylor spatial frame parameters

Long Bone Fracture Reduction and Deformity Correction Using the Hexapod External Fixator With a New Method: a Feasible Study and Preliminary Results

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