NCRP commentary no. 33-recommendations for stratification of equipment use and radiation safety training for fluoroscopy.

National Council on Radiation Protection and Measurements Commentary No. 33 'Recommendations for Stratification of Equipment Use and Radiation Safety Training for Fluoroscopy' defines an evidence-based, radiation risk classification for fluoroscopically guided procedures (FGPs), provides radiation-related recommendations for the types of fluoroscopes suitable for each class of procedure, and indicates the extent and content of training that ought to be provided to different categories of facility staff who might enter a room where fluoroscopy is or may be performed. For FGP, radiation risk is defined by the type and likelihood of radiation hazards that could be incurred by a patient undergoing a FGP. The Commentary also defines six training groups of facility staff based on their role in the fluoroscopy room. The training groups are based on a combination of job descriptions and the procedures in which these individuals might be involved. The Commentary recommends the extent and content of training that should be provided to each of these training groups. It also provides recommendations on training formats, training frequency, and methods for demonstrating that the learner has acquired the necessary knowledge.

Analysis of the Effectiveness of Second Attempt Endoscopic Retrograde Cholangiopancreatography (ERCP) 24 Hours (Second Day) After Primary Failure.

BACKGROUND: Endoscopic retrograde cholangiopancreatography (ERCP) is a minimally invasive intervention that has established itself as the gold standard therapeutic option for various pancreaticobiliary conditions. Deep cannulation of the common bile duct (CBD) is essential in ERCP. However, cannulation is not possible in approximately 20% of the cases with the usual techniques even when performed by highly trained professionals or at major healthcare institutions. In case of failure on the first attempt, alternative choices include redoing the procedure (on the second attempt) or moving on to more proficient endoscopic methods such as endoscopic ultrasound (EUS) or radiology-aided techniques (rendezvous procedures), totally percutaneous approaches, or surgical treatments. OBJECTIVE: To analyze the effectiveness of the second attempt ERCP 24 hours (second day) after primary failure. METHODOLOGY: This analytical study was conducted to check the outcomes of second attempt ERCP in patients with prior failed cannulation, from June 20, 2023, to November 20, 2023, at the Department of Gastroenterology, Lady Reading Hospital, Peshawar. Patients of either sex, aged >16 years with failed biliary cannulation, and who were otherwise clinically stable were included in the study. Patients with surgically modified anatomy, an unidentified main duodenal papilla, or a history of sphincterotomy at another setup were excluded. Outcomes were assessed in terms of gaining deep biliary access (cannulation) using a therapeutic duodenoscope and endoscopy system supported by a fluoroscope while using a wire-guided sphincterotome. Factors linked to second ERCP cannulation success or failure were analyzed using SPSS version 24. RESULTS: Ninety-four patients were enrolled including 61 (64.9%) males and 33 (35.10%) females. The mean age of the participants was 39.01±14.831 years. The most common indication for the intervention was CBD stones, which were present in 70 (74.5%) patients. Successful cannulation on the second attempt was achieved in 72 (76.6%) patients. Experienced endoscopists achieved a greater proportion of successful cannulation (86.8%) compared to 33.3% by endoscopists with lower experience (p-value: <0.001). Logistic regression analysis was conducted to predict the outcomes (cannulation), which revealed an odds ratio for endoscopist experience of 33.604 (95% confidence interval: 6.948-162.52). CONCLUSION: A second ERCP attempt 24 hours after the primary failed attempt appears to be the best course of action for the majority of clinically stable patients.

Comparative Evaluation of Intraarticular Facet Joint Injection Versus Medial Branch Block in Patients With Low Back Pain: A Randomised Controlled Study.

INTRODUCTION: Lumbar facet joint pain may refer to the back, buttocks, and proximal parts of the lower extremities. Intraarticular facet joint injections, facet joint nerve blocks, or facet joint neurolytic procedures are popular for the management of facet joint pain. MATERIAL AND METHODS: In this prospective, randomised study, 60 patients with a medical evaluation and pain pattern consistent with lumbar facet joint pain were randomly allocated to two groups. Group Ⅰ (n=30) patients were administered fluoroscope-guided lumbar facet joint injection, and group Ⅱ (n=30) patients were administered fluoroscope-guided lumbar facet joint nerve block. The primary objective is to compare the efficacy of both in managing facet joint pain in terms of pain and disability improvement. Secondary objectives were to compare the requirement for repeat injections and parameters related to the block, such as ease of administering the block, and to note the side effects pertaining to either of the blocks. RESULTS: There was a statistically significant improvement in pain score after injection in both groups (p>0.05). The mean pain score in both groups remained less than two at all time intervals throughout the study period (p>0.05) Excellent patient satisfaction was reported by the majority of the patients at different time intervals in both groups. CONCLUSION: Both lumbar facet joint injection and lumbar facet joint nerve block are safe and effective techniques for managing lower back pain patients. Both techniques provide adequate pain relief and disability improvement.

Postoperative hip center position is associated with gait symmetry in range of axial rotation in dysplasia patients after THA.

Background: This study aimed to explore whether pre- or postoperative hip structures or surgical changes significantly influence hip range of motion (ROM) symmetry in patients with hip dysplasia during gait after total hip arthroplasty (THA) and provide possible surgical suggestions. Methods: Fourteen patients with unilateral hip dysplasia underwent computed tomography before and after surgery to create three-dimensional hip models. Pre- and postoperative acetabular and femoral orientations, hip rotation centers (HRC), and femoral lengths were measured. Bilateral hip ROM during level walking after THA was quantified using dual fluoroscopy. The ROM symmetry in flexion-extension, adduction-abduction, and axial rotation was calculated using the symmetry index (SI). The relationship between SI and the above anatomical parameters and demographic characteristics was tested using Pearson's correlation and linear regression. Results: The average SI values for flexion-extension, adduction-abduction, and axial rotation during gait were -0.29, -0.30, and -0.10, respectively. Significant correlations were detected mainly in the postoperative HRC position. A distally placed HRC was associated with increased SI values for adduction-abduction (R = -0.47, p = 0.045), while a medially placed HRC was associated with decreased SI values for axial rotation (R = 0.63, p = 0.007). A regression analysis indicated that horizontal HRC positions significantly determined axial rotational symmetry (R2 = 0.40, p = 0.015). Normal axial rotation SI values were achieved with HRC between 17 mm medially and 16 mm laterally. Conclusions: Postoperative HRC position was significantly correlated with gait symmetry in the frontal and transverse planes in patients with unilateral hip dysplasia after THA. Surgical reconstruction of the HRC to between 17 mm medially and 16 mm laterally may contribute to gait symmetry.

Postoperative Hip Center Position Associated With the Range of Internal Rotation and Extension During Gait in Hip Dysplasia Patients After Total Hip Arthroplasty.

Background: Total hip arthroplasty (THA) for hip dysplasia patients is sometimes complex and compromises pathomorphological changes in these patients. However, it remains unclear whether it is preoperative deformities or postoperative structures or anatomic changes during THA that have the most remarkable correlation with the hip dynamic function during gait. The purpose of this study was to investigate this relationship and propose insights into the surgical reconstruction strategy in patients with developmental dysplasia of the hip. Methods: A total of 21 unilateral hip dysplasia patients received computed tomography scans for the creation of 3D hip models before surgery and at the last follow-up. Acetabular and femoral orientations, hip center positions, and femoral length were measured before and after THA. Hip kinematics of the operated side during gait was quantified using a dual fluoroscopic imaging technique. Pearson correlation and multiple linear regression were performed to evaluate the relationship between hip maximum range of motion in six directions and demographics characters and above hip anatomic parameters before and after THA and their changes in surgery. Results: Pearson correlation analysis found significant correlations with the gait range of motion mainly in postoperative structures, including postoperative hip center positions and acetabulum and combined anteversion. Further multiple linear regression indicated that a laterally placed hip center was significantly correlated with an increased internal rotation (R 2 = 0.25, p = 0.021), which together with increased postoperative acetabulum anteversion explained 45% of external rotation decreasing (p = 0.004). A proximally placed hip center was correlated with more extension (R 2 = 0.30, p = 0.010). No significant demographic characters or preoperative deformities or surgical changes were included into other multiple regression models. Conclusion: Strong correlations between postoperative structures, especially hip center positions and gait range of motion in unilateral hip dysplasia patients after THA were found. It indicated that postoperative prosthesis structures, particularly hip center positions had significant impact on the hip gait motion range and should be treated with particular caution in surgery.

Prospective analysis of intraoperative radiation dose in foot and ankle surgery using mini-C-arm fluoroscopy. Continuous series of 1064 procedures.

INTRODUCTION: Foot and ankle surgeons make daily use of mini-C-arm fluoroscopes. The present study aimed to quantify associated radiation doses. HYPOTHESIS: X-ray exposure for foot and ankle surgeons using a mini-C-arm fluoroscope is below the nuclear safety authority authorized doses of 20 mSv/year for the whole body and crystalline lens, 150 mSv/year for the thyroid and 500 mSv/year for the skin and limbs. MATERIAL AND METHODS: A single-center, single-surgeon prospective series was treated between February 2014 and December 2017. Doses emitted by the mini-C-arm (15cm field) were recorded during 1,064 operations. Doses received by the surgeon were recorded by 3 passive dosimeters (thorax, eyes and hands) and 1 active dosimeter. The significance threshold was set at p<0.05. RESULTS: A total of 64.4% of procedures concerned the forefoot, 35.3% the hindfoot and ankle, and 0.3% were strictly percutaneous. Mean dose-area product (DAP) per procedure was 3.9 cGy/cm2±7: in forefoot surgery, 1.1 cGy/cm2±0.9, and in hindfoot and ankle surgery 8.7 cGy/cm2±9.7 (p<0.05), for mean irradiation times of 7.6s±5.3 and 36.7s±35.5 respectively and image numbers 4.1±2.7 and 18.7±20.5. Total ankle replacement was associated with the highest doses: 20.1 cGy/cm2±14.7. Mean daily active dosimetry was 2.2µSv±1.4. Mean annual dose to the hand, crystalline lens and deep (Hp(10)) and shallow (Hp(0.07)) whole body was respectively 1.28 mSv, 0.6 mSv, 0.31 mSv and 0.19 mSv. The highest annual exposure was recorded for the hands: 2.68 mSv in 2015. There was a significant linear relationship between daily active dosimetry and daily emission: daily active dosimetry=(DAP×0.11)+0.54, for a correlation coefficient of 0.77. DISCUSSION/CONCLUSION: The exposure of foot and ankle surgeons using mini-C-arms was well below threshold, and also lower than in the literature. LEVEL OF EVIDENCE: IV.

Accurate and Minimally Invasive Cervical Pedicle Screw Insertion Procedure Using the Bone Biopsy Needle as Drill Guide.

INTRODUCTION: Cervical pedicle screw (CPS) fixation provides the strongest mechanical stability. It needs, however, wide soft tissue detachment to expose the entry point and carries the potential risk of iatrogenic damage to neurovascular structures. Malposition of the CPS cannot be completely avoided even using the navigation system. TECHNICAL NOTE: Using the bone biopsy needle as drill guide, we developed a novel accurate CPS insertion technique. (1) The entry point of CPS was exposed using Southwick's technique for anterior fixation or Tokioka's technique for posterior fixation. (2) A 13G bone biopsy needle was inserted from the entry point established by the fluoroscopy-assisted pedicle axis view technique described by Yukawa et al. to within a few millimeters of the pedicle. (3) The external sleeve of the bone biopsy needle was left in place as a drill guide, and the 1.25 mm guidewire for a 4.0 mm cannulated screw was then inserted into the pedicle cavity. (4) The external sleeve of the bone biopsy needle was removed, and the screw trajectory was created by a 2.7 mm cannulated drill bit over the guidewire. (5) Tapping was conducted prior to CPS insertion. Using this method, 29 CPSs in nine patients were inserted. Postoperative computed tomography scans revealed that all the CPSs were placed accurately. CONCLUSIONS: Utilizing the bone biopsy needle as drill guide, our procedure enables accurate positioning of CPS without expensive instruments.

A new method for accurately localizing and resecting pulmonary nodules.

With the use of low-dose CT for early screening of lung cancer, more and more early lung cancers are found. At the same time, patients with small lung nodules have also increased, it is a great challenge for surgeons to resect pulmonary nodules with small volume, deep position and no solid components under video-assisted thoracoscopic surgery. Many studies have reported preoperative and intraoperative methods for localizing lung nodules before minimally invasive resection. Methods for preoperative localization include CT-guided hook-wire positioning, coil positioning, or dye injection and radionuclide location Methods for intraoperative localization include intraoperative ultrasound localization and tactile pressure-sensing localization. After the localization of pulmonary nodules under the guidance of CT patients need to restrict their activities; otherwise, it is easy for the nodules to move, causing the operation to fail, and may also cause complications such as pneumothorax, puncture site pain, and pulmonary parenchymal bleeding. In the past, we injected melamine dye under the guidance of electromagnetic navigation bronchoscope to locate lung nodules. The purpose of this case is introducing a new method for accurately localizing and resecting pulmonary nodules by injecting indocyanine green (ICG) under the guidance of electromagnetic navigation bronchoscope and the resection of small pulmonary nodules under the fluoroscope.

Kinematic Evaluation of the GMK Sphere Implant During Gait Activities: A Dynamic Videofluoroscopy Study.

Joint stability is a primary concern in total knee joint replacement. The GMK Sphere prosthesis was specifically designed to provide medial compartment anterior-posterior (A-P) stability, while permitting rotational freedom of the joint through a flat lateral tibial surface. The objective of this study was to establish the changes in joint kinematics introduced by the GMK Sphere prosthesis during gait activities in comparison to conventional posterior-stabilized (PS) fixed-bearing and ultra-congruent (UC) mobile-bearing geometries. The A-P translation and internal/external rotation of three cohorts, each with 10 good outcome subjects (2.9 ± 1.6 years postop), with a GMK Sphere, GMK PS or GMK UC implant were analysed throughout complete cycles of gait activities using dynamic videofluoroscopy. The GMK Sphere showed the smallest range of medial compartment A-P translation for level walking, downhill walking, and stair descent (3.6 ± 0.9 mm, 3.1 ± 0.8 mm, 3.9 ± 1.3 mm), followed by the GMK UC (5.7 ± 1.0 mm, 8.0 ± 1.7 mm, 8.7 ± 1.9 mm) and the GMK PS (10.3 ± 2.2 mm, 10.1 ± 2.6 mm, 11.6 ± 1.6 mm) geometries. The GMK Sphere exhibited the largest range of lateral compartment A-P translation (12.1 ± 2.2 mm), and the largest range of tibial internal/external rotation (13.2 ± 2.2°), both during stair descent. This study has shown that the GMK Sphere clearly restricts A-P motion of the medial condyle during gait activities while still allowing a large range of axial rotation. The additional comparison against the conventional GMK PS and UC geometries, not only demonstrates that implant geometry is a key factor in governing tibio-femoral kinematics, but also that the geometry itself probably plays a more dominant role for joint movement than the type of gait activity. © 2019 The Authors. Journal of Orthopaedic Research® published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 37:2337-2347, 2019.

Knee implant kinematics are task-dependent.

Although total knee arthroplasty (TKA) has become a standard surgical procedure for relieving pain, knowledge of the in vivo knee joint kinematics throughout common functional activities of daily living is still missing. The goal of this study was to analyse knee joint motion throughout complete cycles of daily activities in TKA subjects to establish whether a significant difference in joint kinematics occurs between different activities. Using dynamic videofluoroscopy, we assessed tibio-femoral kinematics in six subjects throughout complete cycles of walking, stair descent, sit-to-stand and stand-to-sit. The mean range of condylar anterior-posterior translation exhibited clear task dependency across all subjects. A significantly larger anterior-posterior translation was observed during stair descent compared to level walking and stand-to-sit. Local minima were observed at approximately 30° flexion for different tasks, which were more prominent during loaded task phases. This characteristic is likely to correspond to the specific design of the implant. From the data presented in this study, it is clear that the flexion angle alone cannot fully explain tibio-femoral implant kinematics. As a result, it seems that the assessment of complete cycles of the most frequent functional activities is imperative when evaluating the behaviour of a TKA design in vivo.

The effect of C-arm fluoroscope on unicompartmental knee replacement arthroplasty.

PURPOSE: The aim of this study was to identify the effectiveness of C-arm fluoroscope in unicompartmental knee replacement arthroplasty through the clinical and radiologic results. MATERIALS AND METHODS: We investigated the 33 cases of unicompartmental knee replacement arthroplasty in 31 patients who diagnosed degenerative arthritis of knee between February 2011 and March 2014. We divided 2 groups, one is 15 cases using C-arm fluoroscope during operation (group A), the other is 18 cases not using that (group B). We measured femoro-tibial angle (FTA), medial proximal tibial angle (MPTA), posterior tibial slope angle (PTSA), femoral component coronal rotation angle (FCRA) by simple X-ray. We evaluated femur and tibia varus/valgus mismatch and posterior slope mismatch by above parameters after operation. And also we evaluated clinically by knee and functional score. RESULTS: In group A, FTA average changes from -0.6° to 6.1°, MPTA changes from 84.5° to 87.6°, PTSA changes from 6.2° to 5.2° through operation. In group B, FTA changes from -0.4° to 5.8°, MPTA changes from 84.7° to 87.1°, PTSA changes from 6.3° to 5.5°, and FCRA is 0.6° in A group, 0.4° in B group after operation. The tibial varus/valgus mismatch cases after operation (nl.:87 ±â€¯3°) was 1 in group A, 5 in group B. Post. slope mismatch cases after operation (nl.:7 ±â€¯3°) was 1 in group A, 1 in group 31 B. All cases in both A and B group were not included in femoral varus/valgus mismatch (nl.:0 ±â€¯3°) after operation. In group A, Knee score improved from 56.3 to 90.7, Functional score from 54.3 to 86.9 through operation. In group B, Knee score improved from 54.9 to 89.8, Functional score from 52.8 to 84.6. CONCLUSION: There was no statistically significant difference in radiologic and clinical results between group A and B, but the number of tibial varus/valgus mismatch case were fewer in fluoroscope guided group. Sowe consider that thefluoroscope is helpful for tibial cuttingin unicompartmental knee replacement arthroplasty.

A comprehensive assessment of the musculoskeletal system: The CAMS-Knee data set.

Combined knowledge of the functional kinematics and kinetics of the human body is critical for understanding a wide range of biomechanical processes including musculoskeletal adaptation, injury mechanics, and orthopaedic treatment outcome, but also for validation of musculoskeletal models. Until now, however, no datasets that include internal loading conditions (kinetics), synchronized with advanced kinematic analyses in multiple subjects have been available. Our goal was to provide such datasets and thereby foster a new understanding of how in vivo knee joint movement and contact forces are interlinked - and thereby impact biomechanical interpretation of any new knee replacement design. In this collaborative study, we have created unique kinematic and kinetic datasets of the lower limb musculoskeletal system for worldwide dissemination by assessing a unique cohort of 6 subjects with instrumented knee implants (Charité - Universitätsmedizin Berlin) synchronized with a moving fluoroscope (ETH Zürich) and other measurement techniques (including whole body kinematics, ground reaction forces, video data, and electromyography data) for multiple complete cycles of 5 activities of daily living. Maximal tibio-femoral joint contact forces during walking (mean peak 2.74 BW), sit-to-stand (2.73 BW), stand-to-sit (2.57 BW), squats (2.64 BW), stair descent (3.38 BW), and ramp descent (3.39 BW) were observed. Internal rotation of the tibia ranged from 3° external to 9.3° internal. The greatest range of anterio-posterior translation was measured during stair descent (medial 9.3 ±â€¯1.0 mm, lateral 7.5 ±â€¯1.6 mm), and the lowest during stand-to-sit (medial 4.5 ±â€¯1.1 mm, lateral 3.7 ±â€¯1.4 mm). The complete and comprehensive datasets will soon be made available online for public use in biomechanical and orthopaedic research and development.

Comparison of High Resolution X-Ray detectors with Conventional FPDs using Experimental MTFs and Apodized Aperture Pixel Design for Reduced Aliasing.

Apodized Aperture Pixel (AAP) design, proposed by Ismailova et. al, is an alternative to the conventional pixel design1. The advantages of AAP processing with a sinc filter in comparison with using other filters include non-degradation of MTF values and elimination of signal and noise aliasing, resulting in an increased performance at higher frequencies, approaching the Nyquist frequency3. If high resolution small field-of-view (FOV) detectors with small pixels used during critical stages of Endovascular Image Guided Interventions (EIGIs) could also be extended to cover a full field-of-view typical of flat panel detectors (FPDs) and made to have larger effective pixels, then methods must be used to preserve the MTF over the frequency range up to the Nyquist frequency of the FPD while minimizing aliasing. In this work, we convolve the experimentally measured MTFs of an Microangiographic Fluoroscope (MAF) detector, (the MAF-CCD with 35µm pixels) and a High Resolution Fluoroscope (HRF) detector (HRF-CMOS50 with 49.5µm pixels) with the AAP filter and show the superiority of the results compared to MTFs resulting from moving average pixel binning and to the MTF of a standard FPD. The effect of using AAP is also shown in the spatial domain, when used to image an infinitely small point object. For detectors in neurovascular interventions, where high resolution is the priority during critical parts of the intervention, but full FOV with larger pixels are needed during less critical parts, AAP design provides an alternative to simple pixel binning while effectively eliminating signal and noise aliasing yet allowing the small FOV high resolution imaging to be maintained during critical parts of the EIGI.

A CMOS-based high resolution fluoroscope (HRF) detector prototype with 49.5 µm pixels for use in endovascular image guided interventions (EIGI).

X-ray detectors to meet the high-resolution requirements for endovascular image-guided interventions (EIGIs) are being developed and evaluated. A new 49.5-micron pixel prototype detector is being investigated and compared to the current suite of high-resolution fluoroscopic (HRF) detectors. This detector featuring a 300-micron thick CsI(Tl) scintillator, and low electronic noise CMOS readout is designated the HRF-CMOS50. To compare the abilities of this detector with other existing high resolution detectors, a standard performance metric analysis was applied, including the determination of the modulation transfer function (MTF), noise power spectra (NPS), noise equivalent quanta (NEQ), and detective quantum efficiency (DQE) for a range of energies and exposure levels. The advantage of the smaller pixel size and reduced blurring due to the thin phosphor was exemplified when the MTF of the HRF-CMOS50 was compared to the other high resolution detectors, which utilize larger pixels, other optical designs or thicker scintillators. However, the thinner scintillator has the disadvantage of a lower quantum detective efficiency (QDE) for higher diagnostic x-ray energies. The performance of the detector as part of an imaging chain was examined by employing the generalized metrics GMTF, GNEQ, and GDQE, taking standard focal spot size and clinical imaging parameters into consideration. As expected, the disparaging effects of focal spot unsharpness, exacerbated by increasing magnification, degraded the higher-frequency performance of the HRF-CMOS50, while increasing scatter fraction diminished low-frequency performance. Nevertheless, the HRF-CMOS50 brings improved resolution capabilities for EIGIs, but would require increased sensitivity and dynamic range for future clinical application.

Focal spot size reduction using asymmetric collimation to enable reduced anode angles with a conventional angiographic x-ray tube for use with high resolution detectors.

The high-resolution requirements for neuro-endovascular image-guided interventions (EIGIs) necessitate the use of a small focal-spot size; however, the maximum tube output limits for such small focal-spot sizes may not enable sufficient x-ray fluence after attenuation through the human head to support the desired image quality. This may necessitate the use of a larger focal spot, thus contributing to the overall reduction in resolution. A method for creating a higher-output small effective focal spot based on the line-focus principle has been demonstrated and characterized. By tilting the C-arm gantry, the anode-side of the x-ray field-of-view is accessible using a detector placed off-axis. This tilted central axis diminishes the resultant focal spot size in the anode-cathode direction by the tangent of the effective anode angle, allowing a medium focal spot to be used in place of a small focal spot with minimal losses in resolution but with increased tube output. Images were acquired of two different objects at the central axis, and with the C-arm tilted away from the central axis at 1° increments from 0°-7°. With standard collimation settings, only 6° was accessible, but using asymmetric extended collimation a maximum of 7° was accessed for enhanced comparisons. All objects were positioned perpendicular to the anode-cathode direction and images were compared qualitatively. The increasing advantage of the off-axis focal spots was quantitatively evidenced at each subsequent angle using the Generalized Measured-Relative Object Detectability metric (GM-ROD). This anode-tilt method is a simple and robust way of increasing tube output for a small field-of-view detector without diminishing the overall apparent resolution for neuro-EIGIs.

Precise 3D/2D calibration between a RGB-D sensor and a C-arm fluoroscope.

PURPOSE: Calibration and registration are the first steps for augmented reality and mixed reality applications. In the medical field, the calibration between an RGB-D camera and a C-arm fluoroscope is a new topic which introduces challenges. METHOD: A convenient and efficient calibration phantom is designed by combining the traditional calibration object of X-ray images with a checkerboard plane. After the localization of the 2D marker points in the X-ray images and the corresponding 3D points from the RGB-D images, we calculate the projection matrix from the RGB-D sensor coordinates to the X-ray, instead of estimating the extrinsic and intrinsic parameters simultaneously. VALIDATION: In order to evaluate the effect of every step of our calibration process, we performed five experiments by combining different steps leading to the calibration. We also compared our calibration method to Tsai's method to evaluate the advancement of our solution. At last, we simulated the process of estimating the rotation movement of the RGB-D camera using MATLAB and demonstrate that calculating the projection matrix can reduce the angle error of the rotation. RESULTS: A RMS reprojection error of 0.5 mm is achieved using our calibration method which is promising for surgical applications. Our calibration method is more accurate when compared to Tsai's method. Lastly, the simulation result shows that using a projection matrix has a lower error than using intrinsic and extrinsic parameters in the rotation estimation. CONCLUSIONS: We designed and evaluated a 3D/2D calibration method for the combination of a RGB-D camera and a C-arm fluoroscope.

Sagittal plane rotation center of lower lumbar spine during a dynamic weight-lifting activity.

This study investigated the center of rotation (COR) of the intervertebral segments of the lower lumbar spine (L4-L5 and L5-S1 segments) in sagittal plane during a weight-lifting (3.6 kg in each hand) extension activity performed with the pelvis constrained. Seven healthy subjects were studied using a dual fluoroscopic imaging technique. Using the non-weightbearing, supine position during MRI scan as a reference, the average intervertebral flexion angles of the L4-L5 and L5-S1 were 6.6° and 5.3° at flexion position of the body, respectively, and were -1.8° and -3.5° at extension position of the body, respectively. The CORs of the lower lumbar spine were found segment-dependent and changed with the body postures. The CORs of the L4-L5 segment were at the location about 75% posterior from the anterior edge of the disc at flexion positions of the body, and moved to about 92% of the posterior portion of the disc at extension positions of the body. The CORs of the L5-S1 segment were at 95% posterior portion of the disc at flexion positions of the body, and moved outside of the posterior edge of the disc by about 12% of the disc length at extension positions of the body. These results could help understand the physiological motion characters of the lower lumbar spine. The data could also provide important insights for future improvement of artificial disc designs and surgical implantation of the discs that are aimed to reproduce normal spinal functions.

Interest of intra-operative 3D imaging in spine surgery: a prospective randomized study.

PURPOSE: We report a single-center, prospective, randomized study for pedicle screw insertion in opened and percutaneous spine surgeries, using a computer-assisted surgery (CAS) technique with three-dimensional (3D) intra-operative images intensifier (without planification on pre-operative CT scan) vs conventional surgical procedure. MATERIAL AND METHOD: We included 143 patients: Group C (conventional, 72 patients) and Group N (3D Fluoronavigation, 71 patients). We measured the pedicle screw running time, and surgeon's radiation exposure. All pedicle runs were assessed according to Heary by two independent radiologists on a post-operative CT scan. RESULTS: 3D Fluoronavigation appeared less accurate in percutaneous procedures (24 % of misplaced pedicle screws vs 5 % in Group C) (p = 0.007), but more accurate in opened surgeries (5 % of misplaced pedicle screws vs 17 % in Group C) (p = 0.025). For one vertebra, the average surgical running time reached 8 min in Group C vs 21 min in Group N for percutaneous surgeries (p = 3.42 × 10(-9)), 7.33 min in Group C vs 16.33 min in Group N (p = 2.88 × 10(-7)) for opened surgeries. The 3D navigation device delivered less radiation in percutaneous procedures [0.6 vs 1.62 mSv in Group C (p = 2.45 × 10(-9))]. For opened surgeries, it was twice higher in Group N with 0.21 vs 0.1 mSv in Group C (p = 0.022). CONCLUSION: The rate of misplaced pedicle screws with conventional techniques was nearly the same as most papers and a little bit higher with CAS. Surgical running time and radiation exposure were consistent with many studies. Our work hypothesis is partially confirmed, depending on the type of surgery (opened or closed procedure).

Tongue acupuncture in treatment of post-stroke dysphagia.

Tongue acupuncture is a technique that treats illness through acupuncture applied to the tongue. This study was designed to assess its therapeutic effects in the treatment of post-stroke dysphagia. A clinical control study was conducted with randomly selected 180 patients with post-stroke dysphagia. The patients were assigned into 2 groups: 90 in the Tongue acupuncture group received tongue acupuncture on the basis of conventional medication, 90 in the conventional acupuncture group received acupuncture on the neck and wrist. Acupoints in the tongue are Juanquan (EX-HN10) (at the midpoint of dorsal raphe of the tongue) and Haiquan (EX-HN11) (Sublingual frenulum midpoint). Acupoits on the body are Fengchi (GB20) and Neiguan (PC6). The effective rate, the national institutes of health stroke scale (NIHSS), TV X-ray fluoroscopy swallowing function (VFSS), the incidence rate of pneumonia were used to evaluate the efficacy after 4 weeks treatment. The NIHSS and VFSS of tongue acupuncture group were improved significantly than that of the conventional group (P < 0.01, respectively). The incidence rate of pneumonia decreased (P < 0. 01). The effective rate of the tongue acupuncture group was higher than that of conventional group (96.67% vs. 66.67%, P < 0. 01). On the basis of the conventional medication, tongue acupuncture would effectively improve the swallow functions, decrease the neurological deficit and reduce the incidence of pneumonia in patients with post-stroke dysphagia.

Fluoroscopy assisted tracheal intubation in a case of anticipated difficult airway: Fail safe devices can also fail.

Difficulty in airway management is the most important cause of major anesthesia-related morbidity and mortality. Unexpected difficulties may arise even with proper preanesthesia planning. Here, we report a case of anticipated difficult airway primarily planned for flexible fibreoptic bronchoscope assisted intubation, but due to unexpected failure of light source, fluoroscopy was used, and the airway was successfully secured.