C-arm Position Research Articles

Fusion Imaging Significantly Reduces Contrast and Radiation Exposure During Standard EVAR

Background: Standard endovascular aortic repair (EVAR) is frequently performed with few data regarding utilization of 2D-3D fusion imaging (FI). Purpose: To evaluate a) feasibility and safety of 2D-3D FI to guide limb deployment during EVAR and b) efficacy of this technique compared to standard use of digital subtraction angiography (DSA) for guidance. Materials and Methods: Iliac limb deployment by guidance of 2D-3D FI (FUSION group, n=22 limbs) during EVAR was compared to (STANDARD group, n=23 limbs). Retrospectively, we analyzed feasibility (success-rate) and safety (patency of hypogastric artery; type Ib/III endoleak) of FI for limb deployment (FUSION group). Total contrast (ml) and median dose area product (mGy*cm2) per group to visualize the iliac bifurcation were compared. Results: In the FUSION group, limb deployment was performed in 19/22 limbs (86.4%) and all hypogastric arteries were patent at the end of the procedure. Median volumes of contrast per bifurcation were 13.0 ml (RANGE 13–13ml) in the STANDARD and 2.2ml (RANGE 0–13ml) in the FUSION group (p=0.002); median dose area products per bifurcation were 11951mGy*cm2 and 2593.1mGy*cm2 (p=0.001), respectively. Conclusion: Fusion imaging for guidance of limb deployment during standard EVAR is safe and feasible in the majority of procedures and can significantly reduce contrast volume and radiation exposure even if compared with optimal preparation by predicting optimal C-arm positions. Therefore, FI should be used whenever possible

Clinical effects of the implantation of porous tantalum rod under three-dimensional C-arm positioning in treating ARCO I-II non-traumatic necrosis of the femoral head

Objective To evaluate the clinical effects of the implantation of porous tantalum rod under three-dimensional (3D) C-arm positioning in the treatment of ARCO I and II non-traumatic femoral head necrosis. Methods Fifty patients (58 hips, 39 males and 11 females, mean age 33.52 years) with non-traumatic femoral head in ARCO I-II were included from January 2009 to December 2011. All patients received implantation of porous tantalum rod. The 3D C-arm X-ray positioning was used in 24 patients (29 hips), while traditional C-arm X-ray positioning was performed in the other patients. The visual analogue scale (VAS), Harris score and superior rate were evaluated at 0.5, 1, 2, and 4 years after the surgery. Total hip arthroplasty was regarded as the end event for survival rate. Results In the 3D C-arm X-ray positioning group, the VAS score decreased from 7.17±1.00 points preoperatively to 2.38±0.86 points at half year, to 2.10±1.40 points at 1 year, to 2.38±1.66 points at 2 years, and to 2.21±1.47 points at 4 years postoperatively (F=98.78, P=0.00). Meanwhile, the Harris score increased significantly from 73.97±3.49 points preoperatively to 89.90±1.93, 89.93±3.26, 89.21±5.83, 88.57±5.70 points at the follow up, respectively (F=84.35, P=0.00). According to the analysis of the pre-operative and post-operative image data, there was no significant difference in progress in the ARCO staging at 23 hips duration the follow-up. Four hips were developed to ARCO III and two hips to ARCO II. Thus, the success rate of operation was 79% (23/29). There were two hips underwent total hip arthroplasty, so the survival rate of femoral head was 93% (27/29). The trend of VAS score and Harris score in the C-arm X-ray positioning group was in accordance with the 3D C-arm X-ray positioning group but without statistically significant difference (P>0.05). The operation duration 31.38±3.96 min, blood loss 36.72±5.59 ml, the ratio of distance of metal rod to bone cortex in femoral neck 0.48±0.10, and the distance of mental rod to center of necrosis 0.18±0.07 cm in 3D C-arm X-ray positioning group was superior to C-arm X-ray positioning group (respectively 41.97±4.64 min, 41.49±4.46 ml, 0.46±0.06, 0.23±0.10 cm, P<0.05). Conclusion The implantation of tantalum rod in treating ARCO I-II non-traumatic femoral head necrosis can increase the function of hip joint, relieve the symptoms of necrosis of femoral head, alleviate the progress of femoral head necrosis in X-ray, and obtain a higher survival rate. The 3D C-arm positioning in surgical operation could improve the accuracy and safety of surgery. Key words: Femur head necrosis; Tantalum; Imaging, three-dimensional; X-rays; Radiography

The effect of surgeon versus technologist control of fluoroscopy on radiation exposure during pediatric ureteroscopy: A randomized trial

Fluoroscopy is commonly used during pediatric ureteroscopy (PURS) for urolithiasis, and the most important contributor to overall radiation exposure is fluoroscopy time (FT). One factor that may impact FT is who controls activation of the fluoroscope: the urologist (with a foot pedal) or the radiation technologist (as directed by the urologist). While there are plausible reasons to believe that either approach may lead to reduced FT, there are no systematic investigations of this question. We sought to compare FT with surgeon-control versus technologist control during PURS for urolithiasis. We conducted a randomized controlled trial (Clinicaltrials.gov ID number: NCT02224287). Institutional Review Board approval was sought and obtained for this study. All subjects (or their legal guardians) provided informed consent. Each patient (age 5-26 years) was randomized to surgeon- or technologist-controlled fluoroscope activation. Block randomization was stratified by the surgeon. For technologist control, the surgeon verbally directed the technologist to activate the fluoroscope. For surgeon control, a foot pedal was used by the surgeon. The technologist controlled c-arm positioning, settings, and movement. The primary outcome was total FT for the procedure. Secondary outcomes included radiation exposure (entrance surface air kerma [ESAK] mGy). We also analyzed clinical and procedural predictors of FT and exposure. Mixed linear models accounting for clustering by surgeon were developed. Seventy-three procedures (5 surgeons) were included. The number of procedures per surgeon ranged from seven to 36. Forty-three percent were pre-stented. Thirty-one procedures were left side, 35 were right side, and seven were bilateral. Stones were treated in 71% of procedures (21% laser, 14% basket, and 65% laser/basket). Stone locations were distal ureter (11.5%), proximal/mid-ureter (8%), renal (69%), and ureteral/renal (11.5%). An access sheath was used in 77%. Median stone size was 8.0mm (range 2.0-20.0). Median FT in the surgeon control group was 0.5min (range 0.01-6.10) versus 0.55min (range 0.10-5.50) in the technologist-control group (p=0.284). Median ESAK in the surgeon control group was 46.02mGy (range 5.44-3236.80) versus 46.99mGy (range: 0.17-1039.31) in the technologist-control group (p=0.362). Other factors associated with lower FT on univariate analysis included female sex (p=0.015), no prior urologic surgeries (p=0.041), shorter surgery (p=0.011), and no access sheath (p=0.006). On multivariable analysis only female sex (p=0.017) and no access sheath (p=0.049) remained significant. There was significant variation among surgeons (p<0.0001); individual surgeon median FT ranged from 0.40 to 2.95min. Fluoroscopy time and radiation exposure are similar whether the surgeon or technologist controls fluoroscope activation. Other strategies to reduce exposure might focus on surgeon-specific factors, given the significant variation between surgeons.

The effect of c-arm tilt on accuracy of intraoperative fluoroscopy in assessing acetabular component position during direct anterior approach for hip arthroplasty

Intraoperative fluoroscopy can improve the precision of acetabular component positioning during direct anterior hip arthroplasty. However, changes in pelvic tilt with c-arm positioning may compromise accuracy. A geometric model of an acetabular component’s projection onto fluoroscopy images was created and manipulated to simulate c-arm tilt. An apparently ideally-placed cup will have its effective anteversion changed by 7.5° with just 10° of caudal/cephalad tilt of the c-arm. This effect is greater in cups that are more horizontally placed or less anteverted. Accurate c-arm positioning is crucial, as small errors in tilt can have considerable effects on final cup position.

Virtual fluoroscopy for intraoperative C-arm positioning and radiation dose reduction.

Positioning of an intraoperative C-arm to achieve clear visualization of a particular anatomical feature often involves repeated fluoroscopic views, which cost time and radiation exposure to both the patient and surgical staff. A system for virtual fluoroscopy (called FluoroSim) that could dramatically reduce time- and dose-spent "fluoro-hunting" by leveraging preoperative computed tomography (CT), encoded readout of C-arm gantry position, and automatic 3D-2D image registration has been developed. The method is consistent with existing surgical workflow and does not require additional tracking equipment. Real-time virtual fluoroscopy was achieved via mechanical encoding of the C-arm motion, C-arm geometric calibration, and patient registration using a single radiograph. The accuracy, time, and radiation dose associated with C-arm positioning were measured for FluoroSim in comparison with conventional methods. Five radiology technologists were tasked with acquiring six standard pelvic views pertinent to sacro-illiac, anterior-inferior iliac spine, and superior-ramus screw placement in an anthropomorphic pelvis phantom using conventional and FluoroSim approaches. The positioning accuracy, exposure time, number of exposures, and total time for each trial were recorded, and radiation dose was characterized in terms of entrance skin dose and in-room scatter. The geometric accuracy of FluoroSim was measured to be [Formula: see text]. There was no significant difference ([Formula: see text]) observed in the accuracy or total elapsed time for C-arm positioning. However, the total fluoroscopy time required to achieve the desired view decreased by 4.1s ([Formula: see text] for conventional, compared with [Formula: see text] for FluoroSim, [Formula: see text]), and the total number of exposures reduced by 4.0 ([Formula: see text] for conventional, compared with [Formula: see text] for FluoroSim, [Formula: see text]). These reductions amounted to a 50% to 78% decrease in patient entrance skin dose and a 55% to 70% reduction in in-room scatter. FluoroSim was found to reduce the radiation exposure required in C-arm positioning without diminishing positioning time or accuracy, providing a potentially valuable tool to assist technologists and surgeons.

Exchange Nailing for Hypertrophic Femoral Nonunion.

Exchange nailing has proven to be a reliable surgical technique for the management of aseptic femoral shaft nonunions. Similar to primary intramedullary nail fixation for femur fractures, exchange nailing for aseptic hypertrophic nonunions of the femur relies on successful navigation of the starting point and proper nail trajectory to minimize coronal and sagittal plane deformities. Compared with the supine position, the lateral decubitus position has the advantage of allowing gravity to displace the soft tissue around the piriformis start site to facilitate nail entry. In addition, the C-arm position and access to the affected limb from both sides by the surgeon and surgical assistant facilitate visualization of existing deformities and the ability to perform correction maneuvers. The purpose of this review is to highlight technical pearls associated with exchange nailing in a lateral decubitus position. Although other techniques are available, and should be used when indicated, exchange nailing provides patients with the opportunity to an early return to activity, improvement in pain and disability, and ultimate bony union.

Mini C-Arm Fluoroscopy: Does Its Configuration Matter for Radiation Exposure to the Surgeon?

The risk of occupational radiation exposure to the surgeon associated with the use of a mini C-arm has yet to reach a wide consensus. Using a distal radius fracture surgery model, we tested the hypothesis that radiation exposure to the surgeon's critical body parts is independent of mini C-arm configuration. An anthropomorphic mannequin (representing the upper body of a 60" male surgeon) was seated at a hand table as if operating on a volar-plated wrist Sawbone model. Thermoluminescent dosimeters measured radiation exposure to the surgeon's eyes, thyroid, chest, hand, and groin from a mini C-arm fluoroscopy unit in 3 commonly used configurations: vertical (source above table), inverted (source below table), and horizontal (with beam parallel to table surface). The fluoroscope scanned the wrist model for 15 continuous minutes in triplicate for each orientation. Radiation to the hand was significantly greatest in all mini C-arm positions compared with all other anatomic sites irrespective of C-arm position. Hand radiation exposure was greatest in the horizontal position (2887.09 mrem), versus the vertical and inverted positions (59.79 mrem, 31.10 mrem, P < .001). Eye radiation exposure was significantly greater in the inverted position (2.33 mrem) compared with the vertical (0.67 mrem, P = .024), and horizontal positions (0.33 mrem, P = .012). No significant difference in radiation exposure was found at the thyroid, chest, and groin sites, at each of the 3 C-arm configurations. The model's hand received almost 1000 times more radiation exposure than all other anatomic sites with statistically greatest radiation exposure sustained in the horizontal position. Eye radiation exposure with the C-arm in the inverted position (below the table) was also significantly greater.

C-arm Positioning Is a Significant Source of Radiation in Spine Surgery.

Prospective chart review. It is well-known that radiation exposure during minimally invasive spine procedures can be substantial. Less interest has focused on setup radiation exposure before incision, including preoperative images used for surgical approach. The present study seeks to better quantify the significance of setup radiation in the total radiation exposure of minimally invasive spine surgery. Radiographic localization is necessary in minimally invasive spine procedures to visualize anatomy, but increased radiation exposure is associated with health risks. Preoperative imaging for anatomical localization has not been previously analyzed as an appreciable source of radiation. From an institutional review board-approved database of more than 1100 procedures, the minimally invasive spine cases with recorded set-up radiation were extracted. The total radiation, set-up radiation, and procedure type data were evaluated. Statistics were generated using a chi-squared analysis. Set-up and total radiation data were collected for 270 spine surgeries performed by four surgeons at two locations. There were 30 thoracic and 240 thoracolumbar/lumbar cases; 78 anterior and 192 posterior cases. Average total radiation (set-up and intraoperative) was 8.04 rad, and average setup radiation was 1.90 rad (28%, std 2.97 rad) across all cases. On average for the thoracolumbar/lumbar cases, set-up radiation accounted for almost 25% of total radiation with 1.76 rad from setup out of 8.16 rad total. Thoracic-only cases often necessitated even more images for localization, generating an average set-up/total percentage of 52%. Across all procedures, set-up radiation significantly increased the total radiation exposure because it accounted for more than 25% of the total procedure. Radiation exposure during preoperative localization can be substantial. Operating room personnel should recognize the high percentage of radiation that occurs during set-up, and merit should be given to techniques and technologies that can limit unnecessary radiation exposure during this portion of the procedure. 2.

Radiation Awareness for Endovascular Abdominal Aortic Aneurysm Repair in the Hybrid Operating Room. An Instant Patient Risk Chart for Daily Practice

Purpose: To determine which patient and C-arm characteristics are the strongest predictors of intraoperative patient radiation dose rates (DRs) during endovascular aneurysm repair (EVAR) procedures and create a patient risk chart. Methods: A retrospective analysis was performed of 74 EVAR procedures, including 16,889 X-ray runs using fixed C-arm imaging equipment. Four multivariate log-linear mixed models (with patient as a random effect) were constructed. Mean air kerma DR (DRAK, mGy/s) and the mean dose area product DR (DRDAP, mGycm2/s) were the outcome variables utilized for fluoroscopy as differentiated from digital subtraction angiography (DSA). These models were used to predict the maximum radiation duration allowed before a 2-Gy skin threshold (for DRAK) or a 500-Gycm2 threshold (for DRDAP) was reached. Results: The strongest predictor of DRAK and DRDAP for fluoroscopy imaging was the radiation protocol, with an increase of 200% when changing from “low” to “medium” and 410% from “low” to “normal.” The strongest predictors of DRAK and DRDAP for DSA were C-arm angulation, with an increase of 47% per 30° of angulation, and body mass index (BMI), with an increase of 58% for every 5-point increase in BMI. Based on these models, a patient with a BMI of 30 kg/m2, combined with 45° of rotation and a field size of 800 cm2 in the medium fluoroscopy protocol has a predicted DRAK of 0.39 mGy/s (or 85.5 minutes until the 2-Gy skin threshold is reached). While using comparable settings but switching the acquisition to a DSA with a “2 frames per second” protocol, the predicted DRAK will be 6.6 mGy/s (or 5.0 minutes until the 2-Gy threshold is reached). Conclusion: X-ray radiation DRs are constantly fluctuating during and between patients based on BMI, the protocols, C-arm position, and the image acquisitions that are used. An instant patient risk chart visualizes these radiation dose fluctuations and provides an overview of the expected duration of X-ray radiation, which can be used to predict when follow-up dose thresholds are reached during abdominal endovascular procedures.

C-arm Positioning Using Virtual Fluoroscopy for Image-Guided Surgery.

Fluoroscopically guided procedures often involve repeated acquisitions for C-arm positioning at the cost of radiation exposure and time in the operating room. A virtual fluoroscopy system is reported with the potential of reducing dose and time spent in C-arm positioning, utilizing three key advances: robust 3D-2D registration to a preoperative CT; real-time forward projection on GPU; and a motorized mobile C-arm with encoder feedback on C-arm orientation. Geometric calibration of the C-arm was performed offline in two rotational directions (orbit α, orbit β). Patient registration was performed using image-based 3D-2D registration with an initially acquired radiograph of the patient. This approach for patient registration eliminated the requirement for external tracking devices inside the operating room, allowing virtual fluoroscopy using commonly available systems in fluoroscopically guided procedures within standard surgical workflow. Geometric accuracy was evaluated in terms of projection distance error (PDE) in anatomical fiducials. A pilot study was conducted to evaluate the utility of virtual fluoroscopy to aid C-arm positioning in image guided surgery, assessing potential improvements in time, dose, and agreement between the virtual and desired view. The overall geometric accuracy of DRRs in comparison to the actual radiographs at various C-arm positions was PDE (mean ± std) = 1.6 ± 1.1 mm. The conventional approach required on average 8.0 ± 4.5 radiographs spent "fluoro hunting" to obtain the desired view. Positioning accuracy improved from 2.6° ± 2.3° (in α) and 4.1° ± 5.1° (in β) in the conventional approach to 1.5° ± 1.3° and 1.8° ± 1.7°, respectively, with the virtual fluoroscopy approach. Virtual fluoroscopy could improve accuracy of C-arm positioning and save time and radiation dose in the operating room. Such a system could be valuable to training of fluoroscopy technicians as well as intraoperative use in fluoroscopically guided procedures.

Pre-operative Simulation of the Appropriate C-arm Position Using Computed Tomography Post-processing Software Reduces Radiation and Contrast Medium Exposure During EVAR Procedures

The aim was to evaluate the feasibility and efficacy of a new method for pre-operative calculation of an appropriate C-arm position for iliac bifurcation visualisation during endovascular aortic repair (EVAR) procedures by using three dimensional computed tomography angiography (CTA) post-processing software. Post-processing software was used to simulate C-arm angulations in two dimensions (oblique, cranial/caudal) for appropriate visualisation of distal landing zones at the iliac bifurcation during EVAR. Retrospectively, 27 consecutive EVAR patients (25 men, mean±SD age 73±7 years) were identified; one group of patients (NEW; n=12 [23 iliac bifurcations]) was compared after implementation of the new method with a group of patients who received a historic method (OLD; n=15 [23 iliac bifurcations]), treated with EVAR before the method was applied. In the OLD group, a median of 2.0 (interquartile range [IQR] 1-3) digital subtraction angiography runs were needed per iliac bifurcation versus 1.0 (IQR 1-1) runs in the NEW group (p=.007). The median dose area products per iliac bifurcation were 11951mGy*cm2 (IQR 7308-16663mGy*cm2) for the NEW, and 39394mGy*cm2 (IQR 19066-53702mGy*cm2) for the OLD group, respectively (p=.001). The median volume of contrast per iliac bifurcation was 13.0mL (IQR: 13-13mL) in the NEW and 26mL (IQR 13-39mL) in the OLD group (p=.007). Pre-operative simulation of the appropriate C-arm angulation in two dimensions using dedicated computed tomography angiography post-processing software is feasible and significantly reduces radiation and contrast medium exposure.

Commentary on “Pre-operative Simulation of the Appropriate C-Arm Position Using Computed Tomography Post-Processing Software Reduces Radiation and Contrast Medium Exposure During EVAR Procedures”

Commentary on “Pre-operative Simulation of the Appropriate C-Arm Position Using Computed Tomography Post-Processing Software Reduces Radiation and Contrast Medium Exposure During EVAR Procedures”

Breast Radiation Exposure in Female Orthopaedic Surgeons.

Breast cancer prevalence is higher among female orthopaedic surgeons compared with U.S. women. The most common breast cancer site, the upper outer quadrant (UOQ), may not be adequately shielded from intraoperative radiation. Factors associated with higher breast radiation exposure (protective apron size and type, surgeon position, and C-arm position) have yet to be established. An anthropomorphic torso phantom, simulating the female surgeon, was placed adjacent to a standard operating table. Dosimeters were placed over the UOQ and lower inner quadrant (LIQ) of the breast, bilaterally. Scatter radiation dose-equivalent rates were measured during continuous fluoroscopy to a pelvic phantom (simulating the patient). Four apron sizes (small, medium, large, and extra-large), 2 apron types (cross-back and vest), 2 surgeon positions (facing the table and 90° to the table), and 2 C-arm positions (anteroposterior and cross-table lateral projection) were tested. The median dose-equivalent rate of scatter radiation to the UOQ (0.40 mrem/hr) was higher than that to the LIQ of the breast (0.06 mrem/hr) across all testing, although this was not statistically significant (p = 0.05). The cross-back aprons provided higher protection to the LIQ compared with the vests (p < 0.05). Lead protection in sizes that were too small or too large for the torso had higher breast radiation dose-equivalent rates. C-arm cross-table lateral projection was associated with higher breast radiation exposure (0.98 mrem/hr) compared with anteroposterior projection (0.13 mrem/hr) (p < 0.001). Breast radiation exposure is higher in a C-arm lateral projection compared with an anteroposterior projection. Higher dose-equivalent rates were observed for the UOQ compared with the LIQ of the breast and for aprons that were too small or too large, although these differences did not reach significance. Factors that may reduce radiation exposure include lead protection of appropriate size and distancing the axilla from the patient and x-ray tube. Increased breast cancer prevalence has been reported for female orthopaedic surgeons. The UOQ of the breast may be at risk for intraoperative radiation exposure. Methods of reducing exposure are warranted.

Commentary on ‘Orthogonal Rings, Fiducial Markers and Overlay Accuracy When Image Fusion is Used for EVAR Guidance’

Image fusion technology is of value because it has the potential to a useful tool, for optimal c-arm positioning and angulation in particreduce intra-operative radiation and contrast dose. It can provide a 3D roadmap to guide intervention limited, by monoplane systems, to a 2D view in real time. The ideal scenario is as follows: A Cone Beam CT (CBCT) is performed at the beginning of the aortic intervention. This 3D data set is then fused with a higher resolution 3D data set from a conventional thin-slice CTscan (TSCT) and a high quality 3D road map (the fusion image) is produced which obviates or greatly reduces the need for any further contrast use throughout the procedure until completion. Vessel cannulation and device delivery takes place solely based on the Fusion Image (FI), used as a 3D roadmap. Enthusiasm for this technology has been borne out by several publications indicating that, compared with conventional techniques, the application of fusion imaging to both complex and noncomplex aortic interventions is associated with shorter procedure times, less contrast use, and lower radiation dose. Clearly such benefits can be achieved, and not necessarily require precise alignment between the FI and the real time target on fluoroscopy. Koutouzi et al. present an important paper, quantifying the accuracy of 3D CT image fusion for EVAR and indicating the shortfall that exists with current techniques. Firstly examining how the CBCT compares with TSCT in producing the FI and secondly how the FI compares with the DSA image prior to device deployment. Acceptable accuracy was defined as <3 mm misalignment between renal arteries when fusing the TSCTwith theCBCT.Thiswas achieved inonly 37%ofpatients when registration was performed manually using L1 and L2 vertebral alignment, and in none when using an automated process. This suggests that the position of the aorta and the renal arteries relative to the vertebral columnvaries from the TSCT to the intraoperatively CBCT.We also see variation between the CBCT and the pre-deployment DSA image (using renal arteries or fiducial markers as reference points). Only 58% of patients had misalignment of 3 mm or less. Part of this is shownby the authors tobedue topatientmovement intra-operatively, and part of it, is likely to be related to change in the shape of the aorta caused by stiff wires. We can surmise that the position of the renal arteries relative to bony landmarks varies (albeit by millimetres) from one CT to the next and from a CBCT at the start of an EVAR to the pre-deployment angiogram, with stiff wires or an aortic device in place. Current fusion technology cannot yet compensate for this. The authors’ findings are consistent with other recent publications and also emphasise the importance of ongoing manual re-registration. This labour intensive process, required intra-operatively, is an inconvenience as is the potential for the fusion image to impair visualisation of wires or other markers on fluoroscopy. For now, image fusion remains

Orthopaedic surgeons' use and knowledge of ionizing radiation during surgical treatment for femoroacetabular impingement.

To better understand how radiograph imaging is currently used throughout perioperative care for femoroacetabular impingement (FAI) and to define surgeon knowledge and perspective on radiation safety when treating FAI. An online questionnaire was designed to be completed by hip arthroscopists on the imaging modalities and projections they use during evaluation and treatment of FAI and the associated radiation exposures and safety. A sample of practicing attending orthopaedic surgeons was surveyed via an anonymous survey link emailed to corresponding authors on publications related to FAI. The anonymous survey link was also provided to orthopaedic surgeons at the 2014 Vail Hip Symposium. Ninety-one surgeons completed the survey. Of these participants, 72 surgeons (79.1%) indicated they use pre-operative radiographs and intra-operative spot fluoroscopic images during FAI treatment. Thirty-three surgeons (36.3%) use pre-operative computed tomography (CT). Twenty-three surgeons (25.3%) use real-time moving fluoroscopy. A majority of surgeons incorrectly answered multiple-choice questions about which C-arm positions and settings result in the lowest doses of radiation to the surgeon or patient. Eighty-three surgeons (91.2%) indicated they believe most orthopaedic surgeons need to be more informed about radiation safety. This study gives a quantitative representation of the imaging modalities and projections utilized during perioperative treatment for FAI. This study also identified a lack of knowledge of radiation safety among orthopaedic surgeons treating patients with FAI and demonstrates the need for greater education. IV.

Better Prediction of Fluoroscopic C-arm Position for TAVI Procedures by Manual CT Assessment Compared to Automatic Determination Using HeartNavigator Software

Better Prediction of Fluoroscopic C-arm Position for TAVI Procedures by Manual CT Assessment Compared to Automatic Determination Using HeartNavigator Software

Coaching Reduced the Radiation Dose of Pain Physicians by Half during Interventional Procedures.

The increased use of C-arm fluoroscopy in interventional pain management has led to higher radiation exposure for pain physicians. This study investigated whether or not real-time radiation dose feedback with coaching can reduce the scatter dose received by pain physicians. Firstly, phantom measurements were made to create a scatter dose profile, which visualizes the average scatter radiation for different C-arm positions at 3 levels of height. Secondly, in the clinical part, the radiation dose received by pain physicians during pain treatment procedures was measured real-time to evaluate (1) the effect of real-time dose feedback on the received scatter dose, and (2) the effect of knowledge of the scatter dose profile and active coaching, on the scatter dose received by the pain physician. The clinical study included 330 interventional pain procedures. The results showed that real-time feedback of the received dose did not lead to a reduction in scatter radiation. However, visualization of the scatter dose in a scatter dose profile and active coaching on optimal positions did reduce the scatter radiation received by pain physicians during interventional pain procedures by 46.4% (P=0.05). Knowledge of and real-time coaching with the scatter dose profile reduced the dose of pain physicians by half, caused by their increased awareness for scatter radiation and their insight into strategic positioning.

Children’s Orthopaedics

The October 2014 Children’s orthopaedics Roundup360 looks at: spondylolisthesis management strategies; not all cervical collars are even; quality of life with Legg-Calve-Perthe’s disease; femoral shaft fractures in children; percutaneous trigger thumb release – avoid at all costs in children; predicting repeat surgical intervention in acute osteomyelitis; and C-Arm position inconsequential in radiation exposure

The Effect of C-Arm Position on Radiation Exposure During Fixation of Pediatric Supracondylar Fractures of the Humerus.

Closed reduction and percutaneous pinning of a pediatric supracondylar fracture of the humerus requires operating directly next to the C-arm to hold reduction and perform fixation under direct imaging. This study was designed to compare radiation exposure from two C-arm configurations: with the image intensifier serving as the operating surface, and with a radiolucent hand table serving as the operating surface and the image intensifier positioned above the table. We used a cadaveric specimen in this study to determine radiation exposure to the operative elbow and to the surgeon at the waist and neck levels during simulated closed reduction and percutaneous pinning of a pediatric supracondylar fracture of the humerus. Radiation exposure measurements were made (1) with the C-arm image intensifier serving as the operating surface, with the emitter positioned above the operative elbow; and (2) with the image intensifier positioned above a hand table, with the emitter below the table. When the image intensifier was used as the operating surface, we noted 16% less scatter radiation at the waist level of the surgeon but 53% more neck-level scatter radiation compared with when the hand table was used as the operating surface and the image intensifier was positioned above the table. In terms of direct radiation exposure to the operative elbow, use of the image intensifier as the operating surface resulted in 21% more radiation exposure than from use of the other configuration. The direct radiation exposure was also more than two orders of magnitude greater than the neck and waist-level scatter radiation exposure. Traditionally, there has been concern over increased radiation exposure when the C-arm image intensifier is used as an operating surface, with the emitter above, compared with when the image intensifier is positioned above the operating surface, with the emitter below. We determined that, although there was a statistically significant difference in radiation exposure between the two configurations, neither was safer than the other at all tested levels. In contrast to traditional teaching regarding radiation exposure, neither C-arm configuration-with the image intensifier serving as the operating surface or with the image intensifier positioned above a radiolucent hand table-was shown to be clearly safer for pediatric supracondylar humeral fracture fixation.

Direct Beam Radiation Exposure to Surgeons During Pinning of Supracondylar Humerus Fractures

Direct beam radiation exposure to the surgeon, especially to their hands, is extremely common during supracondylar humerus fracture pinnings and results in exposure to significantly greater doses of ionizing radiation when compared with scatter radiation. The purpose of this study was to determine how often surgeons are exposed to direct beam radiation during this surgery and whether the C-arm position and the surgeon's experience influence radiation exposure. In this double blind study, we collected 3842 fluoroscopic still images from 78 closed reduction and percutaneous pinning surgeries for supracondylar humerus fractures performed or supervised by 6 attending surgeons. The percentage of images containing a surgeon's body was calculated as an indicator of direct beam radiation exposure. Total fluoroscopy time, C-arm position (standard or inverted), and whether the primary surgeon was an attending, resident, or both were recorded. Nonparametric statistical analyses were performed. Fluoroscopy lasted for a median of 34 seconds, and the surgeon was exposed to direct beam radiation in a median of 13% of fluoroscopy films, with exposure ranging from 0% to 97% per surgery. Fluoroscopy was significantly longer when the C-arm position was inverted when compared with the standard position (43 vs. 26 s, P=0.034). Surgeons' exposure to direct beam radiation was also slightly greater when the C-arm position was inverted (16% vs. 10%, P=0.087). The duration of fluoroscopy exposure and the percentage of films with the body exposed to radiation did not differ based on whether the surgery was performed by an attending, a resident, or both (P=0.53 and 0.28, respectively). However, the percentage of films with bodily radiation exposure did significantly differ between the attending physicians (P=0.029). Direct beam radiation exposure varied widely between surgeries and surgeons, ranging from none to nearly constant exposure. Surgical time also significantly increased with the C-arm in the inverted position compared with the standard position. Given the significant variation in exposure between attending physicians, it is likely that exposure to direct beam radiation can be avoided with improved awareness about the risk of direct beam radiation exposure and cautious surgical technique. Not applicable.