Fluoroscopy Research Articles

FBG‐driven simulation for virtual augmentation of fluoroscopic images during endovascular interventions

AbstractEndovascular interventions are procedures designed to diagnose and treat vascular diseases, using catheters to navigate inside arteries and veins. Thanks to their minimal invasiveness, they offer many benefits, such as reduced pain and hospital stays, but also present many challenges for clinicians, as they require specialized training and heavy use of X‐rays. This is particularly relevant when accessing (i.e. cannulating) small arteries with steep angles, such as most aortic branches. To address this difficulty, a novel solution that enhances fluoroscopic 2D images in real‐time by displaying virtual configurations of the catheter and guidewire is proposed. In contrast to existing works, proposing either simulators or simple augmented reality frameworks, this approach involves a predictive simulation showing the resulting shape of the catheter after guidewire withdrawal without requiring the clinician to perform this task. This system demonstrated accurate prediction with a mean 3D error of 2.4 1.3 mm and a mean error of 1.1 0.7 mm on the fluoroscopic image plane between the real catheter shape after guidewire withdrawal and the predicted shape. A user study reported an average intervention time reduction of 56 when adopting this system, resulting in a lower X‐ray exposure.

The impact of ureteral access sheaths on radiation exposure in the ureterorenoscopic treatment of urolithiasis.

Ureteral access sheaths (UAS) are widely used in the endoscopic treatment of urolithiasis. In modern medicine, radiation exposure from diagnostics and therapy is increasing; however, the impact of UAS on procedure duration, fluoroscopy time, and radiation exposure is still uncertain. This retrospective study included 1,026 patients who received ureterorenoscopic treatment for urolithiasis between 2016 and 2018 at a large academic center. Patients were dichotomized according to the use of UAS, and propensity score matching was performed based on age, BMI and stone size. Patient demographics, stone size, radiographic density, perioperative complications, and postoperative outcome were assessed. Procedure time and radiation exposure, recorded as the fluoroscopy time and area dose product, were analyzed. In total, 300 patients were successfully matched to the cohort with UAS (n=150) and the cohort without UAS (n=150). Patients' demographics were similar for age, gender, BMI and ASA score (each p>0.05). Median stone size was 8mm and 7.5mm in the cohort with and without UAS (p=0.335). Procedure time showed no differences between the two cohorts (p=0.749). Fluoroscopy time and area dose product were significantly lower in patients treated with the use of UAS (p=0.004; p<0.001). The use of a UAS does not prolong operation time in patients with equivalent stone burden. In addition, the use of a UAS reduces fluoroscopy time and radiation exposure. In the future, to reduce radiation exposure to the patient and medical staff, the use of a UAS should also be considered for limited stone disease.

Open window mapping with extended early meets late algorithm vs. conventional mapping for accessory pathway ablation.

Catheter ablation of accessory pathway is the treatment of choice for patients with symptomatic Wolff-Parkinson-White (WPW) syndrome. Accessory pathway (AP) identification relies on point-by-point mapping, raising the need for more precise and efficient methods. High-density open window mapping (OWM) combined with the extended early meets late (EEML) algorithm, utilizing 3D electroanatomic mapping systems, is a promising alternative. However, its role in clinical practice lacks comprehensive investigation, necessitating a comparison with conventional mapping. A prospective cohort study of patients referred for AP ablation evaluated the OWM strategy, comparing it with a retrospective cohort using conventional mapping. Procedure variables, including radiofrequency (RF), fluoroscopy, mapping and procedure times along with total mapping points were compared. Long-term recurrence rates were assessed. 42 patients in the OWM group and 34 in the conventional group were included. The OWM strategy exhibited a significantly lower total mapping time (p = 0.030) despite acquiring more points (p < 0.001) than the conventional group. OWM was associated with reduced fluoroscopy time (12.0 (9.0-16) vs. 19 (11-30) minutes, p = 0.009) and RF time (p = 0.021). Long-term recurrence rates were comparable between groups (7.1% OWM vs. 17.7% conventional mapping, p = 0.284). At a median follow-up of 16.2 (4.6-39.4) months there were not significant differences in recurrence-free survival (p = 0.509). OWM with the EEML algorithm is a feasible tool for precise AP location and ablation, associated with less fluoroscopy time, RF time, and total mapping time. Long-term recurrence rates were similar to conventional mapping. Prospective studies are warranted for further validation.

Exploring the Relationship Between Foot Position and Reduced Risk of Knee-Related Injuries in Side-Cutting Movements

Background: Knee-related injuries often result from poor movement patterns that destabilize the joint and increase stress on knee structures. Understanding the influence of foot positioning on knee biomechanics is critical for identifying high-risk movement patterns and preventing injuries. Methods: Twenty healthy male participants performed side-cutting movements at three different foot progression angles. One participant’s data were used to develop and validate a knee finite element model with high-speed dual fluoroscopic imaging (DFIS). Combined with a musculoskeletal analysis, the model simulated internal knee loads under various foot-positioning conditions. Results: The analysis revealed that, as the external foot progression angle increased, the ankle plantarflexion decreased, while the ankle internal rotation and knee valgus moments increased. Higher stress concentrations were observed on the ACL, lateral meniscus, lateral tibial cartilage, and medial collateral ligament, particularly at the femoral–tibial ACL attachments. Conclusion: The findings suggest that a toe-out foot position elevates the risk of knee injuries by increasing stress on key structures, whereas a toe-in position may enhance joint stability, reduce the ACL injury risk, and promote favorable muscle activation patterns.

Impact of a Prototype 29:1 Ratio Grid on Image Quality and Radiation Dose in Abdominal Angiography

Objectives The aim of this study was to evaluate the impact of a prototype grid with a 29:1 ratio (r29) and a 15:1 (r15) grid on the image quality (IQ) and radiation dose in abdominal angiography. Materials and Methods Six typical abdominal angiographic image scenarios were created in 4 pigs. Polymethylmethacrylate and aluminum plates were used to add 10 cm of patient equivalent thickness to simulate different body types. Fluoroscopic images were acquired with a source-to-image receptor distance of 120 cm. Tantalum- and iron-specific acquisition protocols at different IQ levels were acquired. IQ of radiation dose equivalent image pairs, created with the r29 and r15 grids, respectively, was quantitatively evaluated using contrast-to-noise ratio (CNR) measurements. Differences in radiation dose were estimated using the dose-weighted CNR. Two blinded readers compared IQ of these images using a Likert scale. In a second step, the readers selected pairs of the r29 and r15 images with subjectively equivalent IQ. Radiation doses were then compared. Results Compared with the r15 grid, the r29 grid images achieved similar CNR at an average of 26% (±12%) lower radiation dose at a mean patient equivalent thickness of 26 cm and 36 cm. Both readers noted a significant increase in IQ (P &lt; 0.001) for dose equivalent images, whereas the interobserver agreement was 0.59. For the selected IQ equivalent images, a radiation dose reduction of 38% (±17%; P &lt; 0.001, interobserver agreement 0.92) was noted when using the r29 grid. Conclusions The use of an r29 grid at a large source-to-image receptor distance can significantly improve the IQ compared with the r15 grid at the same radiation dose in abdominal angiography or can reduce radiation dose while preserving IQ.

The Dreaded Cholangiogram: Fluoroscopic Findings for Timely Diagnosis

Abstract This study presents the fluoroscopic image of hilar cholangiocarcinoma (Klatskin tumor) in a young adult male with accelerated hypertension. The image captures the characteristic biliary obstruction at the hepatic hilum, underscoring the diagnostic value of fluoroscopy in identifying biliary tract malignancies. It aims to highlight the importance of timely imaging for management decisions in such cases.

Evaluation of the true lateral fluoroscopic projection for the relation of the S1 recess/foramen to safe corridors in transiliac-transsacral screw placement in human cadaveric pelves

IntroductionPercutaneous screw fixation is a widely used treatment for posterior pelvic ring injuries. Transiliac-transsacral screw fixation has demonstrated superior biomechanical properties over bilateral sacroiliac screws, particularly in the minimally displaced bilateral sacral fractures. Screw placement under fluoroscopic control is still common, while CT navigation is gaining popularity. However, the accurate placement of screws within a safe zone is essential to avoid neurovascular complications.MethodsAn anatomical study using human cadaveric pelves was conducted to assess radiological landmarks and determine a safe zone in relation to the S1 recess/foramen for transiliac-transsacral screw placement.ResultsFourteen pelves were evaluated. Ten pelves were classified as having a satisfactory corridor for screw placement, while four were deemed to have an impossible or high-risk corridor. A safe zone was defined based on the diagonal bisector of the S1 vertebral body, ICD and anterior cortex.DiscussionThe study findings suggest that lateral fluoroscopic projection can determine a safe entry point for screw placement. Understanding the anatomy and landmarks on lateral fluoroscopic images is crucial for successful screw placement and avoiding complications.ConclusionThe S1 body diagonal is consistently located anterior to the S1 recess in lateral fluoroscopic projections, providing a potential safe corridor for transiliac-transsacral screw placement at the S1 level in nondysmorphic pelves. Further research is needed to confirm these findings with CT imaging and evaluate the technical feasibility of screw placement.

Intraoperative angulation of the C-arm for X-ray of each curved surface of the femoral neck wall: a cadaveric study.

C-arm fluoroscopy is the main method assisting surgical reduction and internal fixation of the femoral neck, as traditional anteroposterior and lateral fluoroscopy is insufficient for visualizing the irregular anatomical structure of the femoral neck. We analysed the anatomy of the femoral neck to ascertain the optimal position and angle of the C-arm for adequate visualization of the femoral neck during fluoroscopy. The femoral neck was divided into anterior, posterosuperior and posteroinferior surfaces. These surfaces and the coronal plane of the femur formed the anterior surface coronal angle (ACA), posterosuperior surface coronal angle (PSCA) and posteroinferior surface coronal angle (PICA), respectively. Three angles of 32 dried femoral samples were measured. In the aluminium model, steel wires penetrated the femoral neck wall, whereas, in the wire model, three Kirschner wires penetrated the femoral neck wall. The C-arm was rotated 5° for a 0°-180° fluoroscopic view of each curved surface. Each specimen was imaged, totalling 111 frames. The optimal angle for fluoroscopic imaging of each surface was ascertained, and fluoroscopic features of the Kirschner wire penetrating the femoral neck cortex at three different angles on fluoroscopy and anteroposterior and lateral radiographs were observed. The femoral neck is irregularly shaped and cylindrical, with the anterior surface longer than the posteroinferior surface. The ACA, PSCA and PICA were 31 ± 4.589°, 67.813 ± 5.052° and 168.688 ± 3.206°, respectively. The optimal angles for visualizing the anterior, posterosuperior and posteroinferior surfaces of the steel wire aluminium foil model under fluoroscopy were 30.781 ± 5.464°, 67.969 ± 3.721°, and 167.813 ± 4.319°, respectively. There was no significant difference in the measurements of the corresponding surface coronal angles (P > 0.05). Kirschner wires penetrating the femoral neck wall were difficult to visualize on traditional anteroposterior and lateral films. Increasing the angle to 30°, 70° or 170° for fluoroscopy allowed clear visualization of Kirschner wires penetrating the femoral cortex. Traditional anteroposterior and lateral fluoroscopic views are insufficient for clear visualization of the true structure of the femoral neck. Additionally, increasing the angle to 30°, 70° or 170° for fluoroscopy allows observation of the fracture reduction quality from the anterior surface, posterosuperior surface and posteroinferior surface of the femoral neck and the damage to the corresponding cortical bone caused by internal fixation. Level II.

Spinal navigation with AI-driven 3D-reconstruction of fluoroscopy images: an ex-vivo feasibility study

BackgroundWith the increasing number of surgeries utilizing spinal instrumentation, three-dimensional surgical navigation aims to improve the accuracy of implant placement. However, its widespread clinical adaption has been hindered by factors such as high radiation exposure and interference with standard surgical workflows.MethodsX23D is a novel AI-based fluoroscopy reconstruction technique that generates a 3D anatomical model of the spine from only four fluoroscopy images. Based on this technology, we developed a prototype for the surgical navigation of pedicle screws placement of the lumbar spine, visualizing the 3D-reconstructed spine anatomy and the surgical drill position in real-time. An ex-vivo study was conducted to compare the accuracy of the X23D-based navigation approach with fluoroscopy-aided freehand instrumentation. Five board-certified surgeons placed pedicle screws on six human torsi within a realistic surgical environment. Breach rate, site and extent (Gertzbein-Robbins) were evaluated in postoperative CT scans, as well as execution time, radiation dose, and user experience. Specimens, operating side, and surgeon were randomised.ResultsForty-nine pedicle screws (n = 24 × 23D, n = 25 2D-fluoroscopy) were evaluated, with six breaches occurring in the control group, one of which was considered clinically significant (medial breach grade C). Five breaches with one clinically significant breach were observed in the X23D group. Breach rate, execution time for each lumbar level (X23D 167 s vs. control 156 s), radiation dose (X23D 33.26 mGy vs. control 49.5 mGy), and user experience did not reveal significant differences (p > 0.05) between the groups.ConclusionsSpinal navigation using the X23D-based approach shows promise and performs well in a realistic surgical ex-vivo setting. With further refinements, its accuracy is expected to match clinical-grade navigation systems while reducing radiation dose.

Intraoperative Detection of Screw Penetration Following Volar Plating of the Distal Radius: A Cadaveric Study Comparing Fluoroscopic Imaging and Ultrasound

Abstract Introduction Hardware prominence is one of the major established complications following volar plating of distal radius fractures. The purpose of this cadaveric study is to compare two conventional fluoroscopic imaging views (carpal shoot-through view [CSV] and dorsal horizon view [DHV]) with ultrasound (US) to establish the best intraoperative imaging modality for surgeons to use to identify penetration of screws through the dorsal cortex and/or into the distal radioulnar joint (DRUJ). Materials and Methods Twelve human cadaveric limbs were included in the study, instrumented with distal radius plates via a volar approach. The three imaging modalities, CSV, DHV, and US, were compared in terms of detecting prominent screws during volar plate fixation. Six surgeons with varying levels of expertise performed the evaluations. Sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and the area under the receiver operating characteristic curve were computed for every surgeon and imaging method. Results The CSV was found to be more sensitive compared with the DHV and US for detecting dorsal cortex penetration (99% vs. 94% vs. 56%, respectively). The DHV was found to be more sensitive in recognizing DRUJ screw penetration compared with CSV and US (89% vs. 78% vs. 11%, respectively). US evaluation demonstrated considerably lower diagnostic utility compared with CSV and DHV. Surgeon's ability to perform as well as confidence in evaluating for screw penetration was highest with the CSV view. Conclusion Fluoroscopic imaging, particularly the CSV, demonstrates greater diagnostic reliability compared with US for intraoperative detection of prominent screws following volar plate fixation of the distal radius. CSV was also identified as the most reproducible examination for all levels of expertise with minimal formal training required. Level of Evidence: Therapeutic level V.

A radiation therapy platform to enable upright cone beam computed tomography and future upright treatment on existing photon therapy machines

AbstractBackgroundThe conventional lying down position for radiation therapy can be challenging for patients due to pain, swallowing or breathing issues. To provide an alternative upright treatment position for these patients, we have developed a portable rotating radiation therapy platform which integrates with conventional photon treatment machines. The device enables cone‐beam computed tomography (CBCT) imaging of patients in an upright position, and the future delivery of therapeutic radiation.PurposeTo design, manufacture, and test a device for upright radiation therapy. A collaborative partnership between physicists, engineers, radiation therapists, radiation oncologists, implementation researchers and consumers was established, to create a device that meets both the clinical and technical requirements of upright radiation therapy. The device is central to a clinical trial (ACTRN12623000498695) which will evaluate upright image quality in the context of future image guided radiation therapy for patients with lung cancer or head and neck cancer.MethodsThe weight and physical constraints of the device were assessed with respect to the American civilian population. The final design was evaluated with a series of tests to characterize the angular accuracy of the platform rotation and the reproducibility of the platform setup position in a radiation treatment room. To acquire an upright CBCT, the platform movement system was synchronized to the kilo‐voltage fluoroscopic imaging on an existing treatment machine. The accuracy of the synchronization was evaluated by assessing the positional reproducibility of upright CBCT imaging of a chest phantom.ResultsThe platform has a weight limit of up to 125 kg which is suitable for approximately 90% of males and 95% of females. The platform has physical constraints that accommodate approximately 95.6% of males and 99.6% of females: a maximum seated height of 97.5 cm, a maximum hip breadth of 63.0 cm, and maximum elbow to knuckle length of 46.5 cm. The angular accuracy of the motion system is within ±0.15° over a full rotation, which is within the guidelines for machine movement accuracy in radiation therapy (1 mm/1°). The platform is a portable device and can be reproducibly positioned in a radiation therapy treatment room with a translational range within ±0.04 mm and a rotational range within ±0.025°. The CBCT imaging can reproducibly detect the position of a chest phantom with a translational uncertainty of ±0.07 mm and a rotational uncertainly of ±0.22°, when imaging is acquired following a strict procedure.ConclusionThe upright radiation therapy platform is suitable for the evaluation of CBCT imaging in the context of image guided radiation therapy. The platform will allow the investigation of open questions in upright radiation therapy in the areas of patient experience, positional stability, anatomical changes, and treatment delivery. Improvements to the materials in the radiation beam line, synchronization with the existing treatment machine, and increasing the device weight limit are suggested prior to delivery of future upright treatments.

Evaluation of 3D‐printed patient‐specific guides to facilitate fluoroscopic‐assisted Kirschner wire stabilization of simulated capital physeal fractures in 3D‐printed dog femur models

AbstractObjectiveTo compare the efficiency and accuracy of freehand and three‐dimensionally printed (3DP) guide‐facilitated fluoroscopic‐assisted Kirschner wire placement in the femoral capitis performed by novice and experienced surgeons.Sample population3DP models of five skeletally immature dog femurs were replicated.MethodsVirtual surgical planning was done to position three parallel, virtual Kirschner wires inserted from the lateral subtrochanteric surface of the femur, coursing proximomedially through the femoral neck to engage the central capitis without penetrating the subchondral bone. Patient‐specific guides were designed and 3DP to facilitate optimal Kirschner wire placement in each femoral model. Four faculty surgeons and four surgery residents performed freehand fluoroscopic‐assisted wire placement in the femoral models. Wire placement was repeated ≥1 month later using the 3DP guides. Surgical time, number of times wires were redirected, number of fluoroscopy images acquired and Likert scores from the participants were recorded. Post‐procedural CTs of the femur models were used to assess wire placement by 3D analysis.ResultsThe number of fluoroscopy images was greater (p &lt; .001) and procedure time was longer (p &lt; .001) for freehand applications, while Likert scores were greater (p &lt; .001) for 3DP‐guide applications. Wire placement was more accurate with 3DP guides. Subchondral bone penetration occurred more frequently during freehand applications (p &lt; .01).Conclusion3DP patient‐specific guides resulted in faster, simpler, and more accurate Kirschner wire placement than freehand placement for both novice and experienced surgeons. Further cadaveric and clinical studies are warranted to evaluate the utility of 3DP patient‐specific guides to facilitate minimally invasive fluoroscopic‐assisted femoral capital physeal fracture stabilization in dogs.

The effect of manipulation under anesthesia on knee kinematics in individuals with arthrofibrosis after anterior cruciate ligament reconstruction.

Manipulation under anesthesia (MUA) has been recommended for refractory arthrofibrosis after anterior cruciate ligament (ACL) reconstruction. However, the effectiveness of MUA to restore normal kinematics of the arthrofibrotic knee is still unclear. The objective of this study was to evaluate tibiofemoral and patellofemoral kinematics in six degrees-of-freedom (6DOF) in patients with arthrofibrosis before and after MUA. Computed tomography and dual fluoroscopic imaging system were used to assess in vivo knee kinematics. Ten patients (6 women and 4 men; 32.6 ± 6.5y, 168.4 ± 7.8cm, 61.8 ± 13.2kg) were included in this study. The tibiofemoral and patellofemoral kinematics in 6DOF were collected before and one year after MUA. A simple analysis of variance was used to evaluate kinematic data of preoperative arthrofibrotic knee, postoperative arthrofibrotic knee, and the contralateral knee. The patella in the postoperative arthrofibrotic knee shifted significantly more inferiorly compared to the preoperative knee at 45° (P = 0.010), 60° (P = 0.008), and 75° (P = 0.049) of flexion. The patellar flexion in the postoperative arthrofibrotic knee significantly increased at 45° (P = 0.048), 60° (P = 0.037), and 75° (P = 0.006) of flexion compared to the preoperative arthrofibrotic knee. The patellar tilt was significantly decreased at 60° (P = 0.006) and at 75° (P = 0.037) of knee flexion in the postoperative arthrofibrotic knee compared to the contralateral knee. MUA significantly increased tibial internal rotation angle in the arthrofibrotic knee at 45° (P = 0.047), at 60° (P = 0.033), and at 75° (P = 0.021) of knee flexion. MUA could restore normal patellar inferior shift, flexion, and tibial rotation compared to the contralateral side. However, the MUA could not restore normal patellar tilt of the arthrofibrotic knee. This indicated that improvement of patellar tilt should be emphasized in postoperative rehabilitation.

Minimally invasive interventional guided imaging therapies of musculoskeletal tumors.

Historically, musculoskeletal (MSK) tumors, which include both bone and soft tissue tumors, have been managed as distinct entities. The incidence of metastases, particularly bone metastasis, in patients with MSK tumors can result in the emergence of significant complications such as pain, impairment of vital anatomical structures, or pathological fractures. Given these issues, a diverse team of experts is typically engaged in intricate treatment decision-making concerning the necessity of surgery, radiation, chemotherapy, or a mix of these methodologies. Nevertheless, percutaneous image-guided minimally invasive interventional therapy for MSK tumors represent a promising approach for treating such tumors. Over the past decade, significant progress has been made in this technique, leading to its growing acceptance in ordinary clinical practice. MSK tumors can be effectively treated by the use of ablation techniques, either as standalone procedures or in conjunction with other percutaneous treatments. Various image-guided techniques have been employed to observe the ablation zone and nearby structures, such as fluoroscopy, ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI). However, CT is the favored method due to its widespread availability and ability to visualize the tumor and its environs. The procedures employed include ethanol injection, radiofrequency ablation, microwave ablation, cryoablation, and magnetic resonance (MR)-guided high-intensity focused ultrasound (HIFU). The technique can be performed in combination with cementation, with or without additional metallic stabilizing devices, depending on the location of the lesion. Improved local tumor control can be attained by combining ablation with bland embolization or transarterial chemoembolization. This article provides an overview of the fundamental elements of minimally invasive interventional guided imaging therapy for MSK malignancies.

Safety and efficacy of brachial approach for coronary angiography and percutaneous coronary intervention

Abstract Background There are many feasible ways to reach the coronary arteries through a percutaneous technique. Till now, the most commonly used approach is the radial artery approach because it has the lowest risk of known vascular adverse events. However, it could not be an option in some situations as congenital radial artery hypoplasia and radial artery spasm. In these cases, the second most common access is the femoral artery access. The current literature over the brachial artery access is controversial. Our study's objective is to verify the brachial artery approach's effectiveness and safety. Methods We studied 300 patients who underwent elective coronary angiography and percutaneous angioplasty in our institution with failed radial access between August 2022 and February 2023. They were classified into two groups; 150 patients in a group with brachial access and 150 in a group with femoral access. Baseline clinical and demographic traits of all enrolled patients were obtained from hospital records and the cardiovascular risk factors were identified. Venous blood samples, resting 12-lead electrocardiogram and transthoracic echocardiography were done before the coronary angiography. Access, procedural and fluoroscopy times were recorded. Doppler evaluations of both brachial and femoral arteries were done the day after the procedure. All patients were examined carefully immediately after the procedure and before discharge to assess any complications. Results Our data showed that no statistically significant difference between the studied groups regarding the cardiovascular risk factors, demographic, clinical and laboratory characteristics. Left brachial access was used more frequently than left femoral access (32.7% vs. 22.7%, p= 0.05), but no significant difference regarding right sided or bilateral access. Procedure time, fluoroscopy time, and contrast volume did not differ significantly (p=0.19, 0.06 and 0.1 respectively). However, brachial group had shorter access time (2.6 ±1.1 vs. 3.4 ± 0.7 minutes, p=0.05) and shorter hospital stay (3.5 ± 1.1 vs. 5.9 ± 1.3 days, p&amp;lt;0.001). Regarding complications, both major and minor complications were significantly lower in the brachial arm (p=0.04 and 0.05, respectively). Conclusion Brachial artery access is a safe, efficient alternative and non-inferior to the femoral route for coronary intervention whenever radial access is not an option.

Regional variations of mechanical responses of IVD to 7 different motions: An in vivo study combined with FEA and DFIS

The abnormal mechanical behaviour of a lumbar intervertebral disc (IVD) is commonly recognized as a direct indicator of intervertebral disc degeneration (IDD). However, current methods cannot evaluate the patient-specific mechanical performance of an IVD in vivo during movement. This study establishes a patient-specific (PS) model that combines the kinematics parameters of the lumbar spine obtained with a dual fluoroscopic imaging system (DFIS) and a finite-element (FE) method for the first time to reveal the mechanical behaviours of IVDs in vivo under seven motions. Three healthy participants were recruited for this study. CT images were obtained to create finite-element models of L3-L5 spine segments. Meanwhile, participants were required to take specific positions including upright standing, flexion, extension, left and right lateral bending, as well as left and right axial torsion in the DFIS. The in vivo kinematic parameters, calculated by registering the CT images with images obtained with DFIS, were considered as loading conditions in FE simulations. Significant differences of von Mises stresses and principal strains were found between PS model and GN model which employing a generalized moment as loading conditions, former resulting in up to 76.74 % lower strain than the GN model. Also, considerable differences were observed for five anatomical regions of the IVD (L3-L5). Under all motions, the stress in the centre region (nucleus pulposus) was the lowest, while the stress in the posterior region was the highest in extension motion. Therefore, activities such as stretching with an extension, should be avoided by patients with a herniated disc, in which the posterior region was the herniation site. The PS model combining in vivo kinematics and FE simulations shows the potential in the design and assessment of patient-specific implants.

Clinical usability and efficacy of a robotic bone fracture reduction system: A pilot animal study

Challenges in minimally invasive surgeries, such as intramedullary nailing for long bone fractures, include radiation overexposure for patients and surgeons, potential malreduction, and physical burden on surgeons in maintaining the reduction status. A robotic bone fracture reduction system was developed in this study to address these problems. The system consists of a hexapod with six degrees of freedom, with a fracture reduction device and a master device. This study aimed to evaluate the novel system in a preclinical setting. The length of the six axes in the system can be adjusted to precisely control the length, angle, and rotation so that no additional traction is required. Fluoroscopic images can be remotely examined to reduce the risk of radiation exposure for surgeons. In this study, alignment accuracy and radiation exposure were measured using 32 bovine bone fracture models, and these surgical outcomes were compared to those of conventional manual surgery to verify the clinical usability and effectiveness of the system. The alignment accuracy was assessed by analyzing length, angulation, and rotation. The four surgeons participating in this study were divided into two groups (expert and novice) according to their clinical experience. All parameters in robotic surgery significantly decreased by approximately 4 mm and 8° on average (p ≤ 0.05) compared to conventional surgery. The mean radiation exposure in robot-assisted surgery was 0.11 mSv, showing a significant decrease compared to conventional surgery (p < 0.05). Reduction accuracy was higher in robotic surgery performed by the novice group than in conventional surgery performed by the expert group; however, standard deviation values were inversed. In conclusion, the bone fracture reduction robot system increased the alignment accuracy through precise control while reducing radiation exposure in surgeons, as the surgery was performed remotely. The use of this system is predicted to improve the accuracy and reproducibility of the surgery and the safety of medical staff.11Abbreviations: CT, computed tomography; FRD, fracture reduction device; FRMD, fracture reduction master device; SD, standard deviation

A new method to evaluate fluoroscopic system collimator performance.

Fluoroscopy uses collimators to limit the radiation field size. Collimators are often evaluated annually during equipment performance evaluations to maintain compliance with regulatory and/or accreditation bodies. A method to evaluate and quantify fluoroscopy collimator performance was developed. A radiation field and displayed image measurement device consisting of radiopaque rulers and radiochromic film strips was placed on the x-ray source assembly exit window to evaluate fluoroscopy collimator performance. This method was used to evaluate collimator performance on 79 fluoroscopic imaging systems including fixed C-arms, mobile C-arms, mini C-arms, and radiographic fluoroscopic systems. The excess length (EL), excess width (EW), and sum EL + EW of the radiation field relative to the displayed image were measured and compared to the limits specified in 21CFR1020.32. Four systems exceeded these limits. Placing the radiation measurement device at the x-ray source assembly exit window relative to the image receptor cover increased the film exposure rate by a factor up to 14.6. The time required to set up and complete the fluoroscopy collimator performance measurements using this method ranged from 5 to 10 min. This method provides an easily implemented quantitative measure of fluoroscopy system collimator performance that satisfies regulatory and accreditation body requirements.

Impact of operative position on rotational alignment after intramedullary nailing of trochanteric fractures: a comparative analysis of lateral decubitus versus supine position.

Fixation of trochanteric fractures with an intramedullary nail in a non-physiological position can cause poor functional outcomes. The aim of this study is to evaluate the effect of intraoperative patient position on rotational alignment in intramedullary nail fixation of trochanteric fractures. The femoral rotational alignment of 84 trochanteric fracture patients who underwent intramedullary nailing was measured by computed tomography (CT) images. Patients were divided into two groups: the supine position on the fracture table (FT) (Group 1, n = 42) and the lateral decubitus (LD) position (Group 2, n = 42). Femoral malrotation angles were measured and divided into three subgroups: insignificant, significant,andexcessive.The number of intraoperative fluoroscopy images, preparation time, surgery time, and anesthesia time in both groups were compared. The malrotation degrees of patients in Group 1 ranged from 17° external rotation (ER) to 57° internal rotation (IR), with a mean of 10° IR. Of the patients in Group 1, 27 were insignificant, 5 were significant, and 10 were in the excessive subgroup. The malrotation degrees of patients in Group 2 ranged from 33° ER to 47° IR, with a mean of 11° IR. Of the patients in Group 2, 21 were insignificant, 12were significant, and 9 were in the excessive subgroup. There was no statistically significant relationship between patient position and malrotation angle. The number of intraoperative fluoroscopy images, preparation time, and anesthesia time were statistically lower in Group 2. There was no statistically significant difference between Group 1 and Group 2 in terms of surgery time. Intramedullary nailing in the LD position is a reliable and practical surgical method in the treatment of femoral trochanteric fractures since there is no need for the use of a FT, the surgeon is exposed to less radiation, there is no risk of complications related to the traction of the FT, and there is a shorter operation time.

Effects of Parallax and Distortion in Total Ankle Arthroplasty.

Surgeons rely on intraoperative fluoroscopy to assist in placement of implant components during total ankle arthroplasty (TAA). Parallax alters the direction of an object when viewed from two different points, resulting in image distortion. The purpose of this study was to evaluate parallax/distortion in intraoperative fluoroscopic images during TAA. A retrospective review of all TAAs performed by two surgeons (R.W.M. and B.S.) from August 2019 to April 2023 were reviewed. Intraoperative fluoroscopic anteroposterior (AP) ankle views were evaluated for any obvious parallax image distortion. Cases with obvious parallax distortion were included for angular evaluation of AP intraoperative fluoroscopic and first postoperative plain films. The tibia was marked at 2-centimeter intervals to create zones from the proximal stem of the implant. The anatomical axis of the tibia (AAT) was drawn at the mid-diaphysis. The anatomic lateral distal tibial angle (aLDTA) and anatomic axis deviation (AAD) were measured for each zone. A total of 22 TAAs were performed during the study period. Four cases were excluded due to inadequate imaging, leaving a total of 18 TAAs for review. We found 6 of 18 (33.3%) cases had obvious parallax distortion. We found the average aLDTA was 90.9° (84°-101°). At the most proximal tibial zone, the average aLDTA was 94° (91°-101°). We found the average AAD was 4.7 (0.5-17.2) mm. The AAD ranged from 0.5 to 17.2 mm lateral to 0.8 to 8.2 mm medial. Postoperative plain film radiographs displayed a normal aLDTA and an AAT centered within the ankle joint. Parallax can distort the appearance of the tibia on fluoroscopic images. Deviation from the normal aLDTA and anatomical axis should be anticipated. Surgeons should be aware of the potential impact of parallax and ways to mitigate these effects.