3D C-arm Research Articles

Robot-Assisted 2D Fluoroscopic Needle Placement-A Phantom Study.

To evaluate the targeting accuracy of a novel robot-assisted guidance technique relying on one pair of 2D C-arm images. In total, 160 punctures were carried out semi-automatically by using a novel robotic device. The needle's paths were planned based on one pair of 2D fluoroscopic images from different angles. Conically shaped aluminum tips inside a gelatin-filled plexiglass phantom served as targets. The accuracy of the needle placement was assessed by taking control CTs and measuring the Euclidean distance (ED) and normal distance (ND) between the needle and the target point. In addition, the procedural time per needle placement was evaluated. The accomplished mean NDs at the target for the 45°, 60°, 75° and 90° angles were 1.86 mm (SD ± 0.19), 2.68 mm (SD ± 0.18), 2.19 mm (SD ± 0.18) and 1.86 mm (SD ± 0.18), respectively. The corresponding mean EDs were 2.32 mm (SD ± 0.16), 2.68 mm (SD ± 0.18), 2.65 mm (SD ± 0.16) and 2.44 mm (SD ± 0.15). The mean duration of the total procedure, including image acquisition, trajectory planning and placement of four needles sequentially, was 12.7 min. Robotic guidance based on two 2D fluoroscopy images allows for the precise placement of needle-like instruments at the first attempt without the need for using an invasive dynamic reference frame. This novel approach seems to be a valuable tool for the precise targeting of various anatomical structures that can be identified in fluoroscopic images.

3D C-arm navigated suture button implantation for AC joint dislocations - the pilot study.

The surgical treatment of acute traumatic AC joint dislocations is still a subject of scientific debate in the literature. The arthroscopically assisted stabilization procedure with a suture button system has been successfully established and is widely used in daily practice. It is minimally invasive and allows the anatomical reconstruction of the torn coracoclavicular ligaments in one step with a permanent implant that does not have to be removed in a second operation. This clinical pilot study is the first to describe the new method of navigated suture button implantation with the future aim of further reducing surgical invasiveness and further increasing surgical precision. 10 patients with a Rockwood 3b/5 injury could be included in the prospective study (DRKS00031855) within 5 months according to inclusion and exclusion criteria. Surgical stabilization was performed with a suture button system via a navigated coracoclavicular drill tunnel. Demographic and radiological data as well as information on health and shoulder function were collected from patient records, X-rays, DVT scan and 3 questionnaires (DASH, NHS and Eq.5D) at the preoperative, intraoperative and postoperative (discharge, 6 weeks and 3 months) time points. All operations could be performed within 8.8 days (± 6.81) after trauma. The average operation time was 50.3min (± 8.81). The mean distance of the drill hole in the clavicle to the AC joint was 26.6mm (± 2.63). The radiologically measured vertical coracoclavicular distance was 38.8mm (± 6.16) at discharge and 41.11mm (± 7.51) at 3 months. This loss of reduction was not statistically significant. In contrast, the DASH, NHS and Eq.5D results showed significant improvement from discharge to 3 months postoperatively. Image-guided 3D C-arm navigated AC joint suture button stabilization is feasible in everyday surgical practice. It may be possible to achieve a further reduction in invasiveness while at the same time increasing the accuracy of implant positioning. Further clinical studies with a larger number of patients and a longer follow-up period are necessary to enable a comparison with conventional methods.

The Method of 3D C-arm Navigated AC Joint Stabilization-Surgical Technique

Background: The arthroscopically assisted stabilization of AC joint dislocations with a suture button system is an established procedure that is widely and successfully used in everyday practice. The main advantages of this one-step method are the minimally invasive procedure and the anatomical reconstruction of the ruptured coracoclavicular ligaments with a permanent implant. With this technical note study, for the first time, the new method of navigated suture button implantation in everyday clinical practice is described with the future goal of further reducing invasiveness and increasing precision. Materials and Methods: The surgical technique is explained using precise descriptions and illustrations, photos, X-rays, and 3D reconstructions based on clinical cases. The step-by-step system setup and patient positioning, AC joint reduction and retention, 3D scan and drill tunnel planning, stab incision and Kirschner wire navigation, and cannulated drilling and implant positioning, as well as closure and documentation are described in detail. Results: The standard coracoclavicular stabilization of AC joint dislocations with the 3D C-arm navigated suture button method is described in detail. Furthermore, the feasibility of an additive horizontal acromioclavicular suture cerclage, the implantation of an additional coracoclavicular suture button system, and the single-stage cannulated screw fixation of non-displaced fractures is demonstrated. Conclusion: The navigated suture button method aims to be simple, safe, minimally invasive, and precise. Prospective clinical studies with a long follow-up should be carried out to determine the clinical and radiological outcome in comparison with current methods.

Evaluation of 3D C-Arm Fluoroscopy versus Diagnostic CT for Deep Brain Stimulation Stereotactic Registration and Post-Operative Lead Localization

Introduction: DBS efficacy depends on accuracy. CT-MRI fusion is established for both stereotactic registration and electrode placement verification. The desire to streamline DBS workflows, reduce operative time, and minimize patient transfers has increased interest in portable imaging modalities such as the Medtronic O-arm® and mobile CT. However, these remain expensive and bulky. 3D C-arm fluoroscopy (3DXT) units are a smaller and less costly alternative, albeit incompatible with traditional frame-based localization and without useful soft tissue resolution. We aimed to compare fusion of 3DXT and CT with pre-operative MRI to evaluate if 3DXT-MRI fusion alone is sufficient for accurate registration and reliable targeting verification. We further assess DBS targeting accuracy using a 3DXT workflow and compare radiation dosimetry between modalities. Methods: Patients underwent robot-assisted DBS implantation using a workflow incorporating 3DXT which we describe. Two intra-operative 3DXT spins were performed for registration and accuracy verification followed by conventional CT post-operatively. Post-operative 3DXT and CT images were independently fused to the same pre-operative MRI sequence and co-ordinates generated for comparison. Registration accuracy was compared to 15 consecutive controls who underwent CT-based registration. Radial targeting accuracy was calculated and radiation dosimetry recorded. Results: Data were obtained from 29 leads in 15 consecutive patients. 3DXT registration accuracy was significantly superior to CT with mean error 0.22 ± 0.03 mm (p < 0.0001). Mean Euclidean electrode tip position variation for CT to MRI versus 3DXT to MRI fusion was 0.62 ± 0.40 mm (range 0.0 mm–1.7 mm). In comparison, direct CT to 3DXT fusion showed electrode tip Euclidean variance of 0.23 ± 0.09 mm. Mean radial targeting accuracy assessed on 3DXT was 0.97 ± 0.54 mm versus 1.15 ± 0.55 mm on CT with differences insignificant (p = 0.30). Mean patient radiation doses were around 80% lower with 3DXT versus CT (p < 0.0001). Discussion: Mobile 3D C-arm fluoroscopy can be safely incorporated into DBS workflows for both registration and lead verification. For registration, the limited field of view requires the use of frameless transient fiducials and is highly accurate. For lead position verification based on MRI co-registration, we estimate there is around a 0.4 mm discrepancy between lead position seen on 3DXT versus CT when corrected for brain shift. This is similar to that described in O-arm® or mobile CT series. For units where logistical or financial considerations preclude the acquisition of a cone beam CT or mobile CT scanner, our data support portable 3D C-arm fluoroscopy as an acceptable alternative with significantly lower radiation exposure.

Effect of changing the acquisition trajectory of the 3D C-arm (CBCT) on image quality in spine surgery: experimental study using an artificial bone model

BackgroundIntraoperative 3D imaging using cone-beam CT (CBCT) provides improved assessment of implant position and reduction in spine surgery, is used for navigated surgical techniques, and therefore leads to improved quality of care. However, in some cases the image quality is not sufficient to correctly assess pedicle screw position and reduction, especially due to metal artifacts. The aim of this study was to investigate whether changing the acquisition trajectory of the CBCT in relation to the pedicle screw position during dorsal instrumentation of the spine can reduce metal artifacts and consequently improve image quality as well as clinical assessability on the artificial bone model.MethodsAn artificial bone model was instrumented with pedicle screws in the thoracic and lumbar spine region (Th10 to L5). Then, the acquisition trajectory of the CBCT (Cios Spin, Siemens, Germany) to the pedicle screws was systematically changed in 5° steps in angulation (− 30° to + 30°) and swivel (− 30° to + 30°). Subsequently, radiological evaluation was performed by three blinded, qualified raters on image quality using 9 questions (including anatomical structures, implant position, appearance of artifacts) with a score (1–5 points). For statistical evaluation, the image quality of the different acquisition trajectories was compared to the standard acquisition trajectory and checked for significant differences.ResultsThe angulated acquisition trajectory increased the score for subjective image quality (p < 0.001) as well as the clinical assessability of pedicle screw position (p < 0.001) highly significant with particularly strong effects on subjective image quality in the vertebral pedicle region (d = 1.06). Swivel of the acquisition trajectory significantly improved all queried domains of subjective image quality (p < 0.001) as well as clinical assessability of pedicle screw position (p < 0.001). The data show that maximizing the angulation or swivel angle toward 30° provides the best tested subjective image quality.SummaryAngulation and swivel of the acquisition trajectory result in a clinically relevant improvement in image quality in intraoperative 3D imaging (CBCT) during dorsal instrumentation of the spine.

Comparison of the Effective Radiation Dose in the Region of the Facial Skull Between Multidetector CT, Dental Conebeam CT and Intraoperative 3D C-Arms

Study Design Experimental single-centre study of X-ray absorption using a phantom skull. Objective This experimental study aimed to compare the radiation doses of different 3D imaging devices used in maxillofacial surgery, including one Multidetector CT (MDCT), two Conebeam CT (CBCT) and four intraoperative 3D C-arms. Methods Thermoluminescent dosimeters (TLD) were used to determine the absorbed radiation in an Alderson-Rando phantom skull. The phantom skull was positioned in the before mentioned seven devices and a defined 3D facial skull image was acquired. Subsequently, the TLD’S were read out and the effective doses (ED) and the organ doses (OD) were calculated and compared. Results OD varied significantly between tissues as well as between the 3D X-ray devices. The OD of the 3D C-arms were significantly lower than those of all other devices. The OD of the CT, especially in the standard setting, was the highest. Only by special adjustments of the scan protocol regarding CMF requirements for traumatology, the MDCT could achieve almost equivalent doses as the two tested CBCT-scanners. The calculated effective doses were also lowest for the 3D C-arm devices (11.2 to 129.9 μSv). The ED of the MDCT were significant higher (284.52–844.97 μSv) than in all other devices. The ED of the CBCTs (173.7–184.9) were lower than for MDCT but still higher than those of the 3D C-arms. Conclusions Intraoperative imaging using 3D C-arm devices is an effective method to verify reduction results in maxillofacial surgery intraoperatively with significantly lower ED than postoperatively CBCT and MDCT imaging.

AAPM Task Group Report 238: 3D C-arms with volumetric imaging capability.

This report reviews the image acquisition and reconstruction characteristics of C-arm Cone Beam Computed Tomography (C-arm CBCT) systems and provides guidance on quality control of C-arm systems with this volumetric imaging capability.The concepts of 3D image reconstruction, geometric calibration, image quality, and dosimetry covered in this report are also pertinent to CBCT for Image-Guided Radiation Therapy (IGRT). However, IGRT systems introduce a number of additional considerations, such as geometric alignment of the imaging at treatment isocenter, which are beyond the scope of the charge to the task group and the report. Section 1 provides an introduction to C-arm CBCT systems and reviews a variety of clinical applications. Section 2 briefly presents nomenclature specific or unique to these systems. A short review of C-arm fluoroscopy quality control (QC) in relation to 3D C-arm imaging is given in Section 3.Section 4 discusses system calibration, including geometric calibration and uniformity calibration.A review of the unique approaches and challenges to 3D reconstruction of data sets acquired by C-arm CBCT systems is give in Section 5. Sections 6 and 7 go in greater depth to address the performance assessment of C-arm CBCT units. First, Section 6 describes testing approaches and phantoms that may be used to evaluate image quality (spatial resolution and image noise and artifacts) and identifies several factors that affect image quality.Section 7 describes both free-in-air and in-phantom approaches to evaluating radiation dose indices. The methodologies described for assessing image quality and radiation dose may be used for annual constancy assessment and comparisons among different systems to help medical physicists determine when a system is not operating as expected. Baseline measurements taken either at installation or after a full preventative maintenance service call can also provide valuable data to help determine whether the performance of the system is acceptable. Collecting image quality and radiation dose data on existing phantoms used for CT image quality and radiation dose assessment, or on newly developed phantoms, will inform the development of performance criteria and standards. Phantom images are also useful for identifying and evaluating artifacts. In particular, comparing baseline data with those from current phantom images can reveal the need for system calibration before image artifacts are detected in clinical practice. Examples of artifacts are provided in Sections 4, 5, and 6.

Comparison of the Accuracy of Pedicle Screw Placement Using a Fluoroscopy-Assisted Free-Hand Technique with Robotic-Assisted Navigation Using an O-Arm or 3D C-Arm in Scoliosis Surgery.

Retrospective. To report and compare the application of robotic-assisted navigation with an O-arm or three-dimensional (3D) C-arm-assisted pedicle screw insertion in scoliosis surgery, and compare with free-hand technique. One hundred and forty-four scoliosis patients were included in this study. Ninety-two patients underwent robotic-assisted pedicle screw insertion (Group A), and 52 patients underwent freehand fluoroscopy-guided pedicle screw insertion (Group B). Group A was further divided into Subgroup AI (n = 48; robotic-assisted navigation with an O-arm) and Subgroup AII (n = 44; robotic-assisted navigation with a 3D C-arm). The evaluated clinical outcomes were operation time, blood loss, radiation exposure, postoperative hospital stay, and postoperative complications. The clinical outcomes, coronal and sagittal scoliosis parameters and the accuracy of the pedicle screw placement were assessed. There were no significant differences in blood loss and postoperative hospital stay between Groups A and B (P = .406, P = .138, respectively). Radiation exposure for patients in Group A (Subgroups AI or AII) was higher than that in Group B (P < .005), and Subgroup AI had higher patient radiation exposure compared with Subgroup AII (P < .005). The operation time in Subgroup AII was significantly longer than that in Subgroup AI and Group B (P = .016, P = .032, respectively). The proportion of clinically acceptable screws was higher in Group A (Subgroups AI or AII) compared with Group B (P < .005). Robotic-assisted navigation with an O-arm or 3D C-arm effectively increased the accuracy and safety in scoliosis surgery. Compared with robotic-assisted navigation with a 3D C-arm, robotic-assisted navigation with an O-arm was more efficient intraoperatively.

Ventriculoperitoneal shunt for brain displacement due to chronic subdural hematoma, using real-time navigated ventriculostomy by three-dimensional robotic C-arm: Technical note

IntroductionVentriculoperitoneal (VP) shunts are widely used in the treatment of hydrocephalus. Optimal ventricular catheter (OVC) placement is required to reduce mechanical dysfunction, particularly when the lateral ventricle is deformed by other factors. We present a novel technique of VP shunt placement through Keen’s point by three dimensional (3D) robotic C-arm navigation in cases of brain displacement due to chronic subdural hematoma (SDH) and post-traumatic hydrocephalus (PTH). MethodsA 74-year-old male with PTH presented with deformed lateral ventricles due to right chronic SDH. A workflow chart of a real-time right ventriculostomy navigation system using a 3D robotic C-arm is introduced. ResultsOVC placement was achieved using virtual surgical planning in a shifted brain case. ConclusionCorrect OVC placement is crucial to the reduction of mechanical dysfunction. Real-time ventriculostomy using 3D robotic C-arm navigation can both reduce the rate of mechanical dysfunction and offer safe and feasible access to the lateral ventricles without causing parenchymal injury, particularly when the ventricles are deformed.

Foreign Bodies Caused by Dental Treatment in the Head and Neck - A Surgical Challenge

Study Design Case series Objective By reporting several cases of dislocated foreign bodies, we aim to make dentists/surgeons aware of possible severe and potentially life-threatening complications. In case of dislocation, the appropriate radiological assessment depending on the foreign body is required if direct removal fails. Material and Methods Electronic and paper record of patients suffering from various dental foreign bodies were analysed. Analysis included history of dislocation, type of foreign object, anatomical region of dislocation, related dental treatment and approach to surgical removal. Results In total, 5 patients with various dental foreign body objects, including fractured root canal instruments (n = 2), a broken dental injection needle (n = 1), a broken Lindemann bur (n = 1) and root filling material (n = 1) are reported. Patient ages ranged from 14 to 54 years. In 4 cases, the foreign body could be salvaged successfully, and one patient refused the surgical therapy. General anaesthesia was required in 4 patients. Intraoperatively, a 3D C-arm was used in 3 cases to ensure the successful recovery of the foreign bodies. In 1 case, the foreign body could be removed with endoscopical assistance. Conclusion The management of dental materials and instruments requires diligent care by the practitioner, and prevention techniques should be used at all times to minimise the patients’ risk. In the case of foreign body dislocation, appropriate radiological assessment and determination of further medical treatment (if necessary) should take place. During surgical procedures, intraoperative 3D-imaging, as well as endoscopic techniques, are helpful tools to ensure the recovery of foreign bodies.

Preliminary outcomes of the surgical navigation system combined with intraoperative three-dimensional C-arm computed tomography for zygomatico-orbital fracture reconstruction

This study analyzed the outcomes of zygomatico-orbital fracture reconstruction using the real-time navigation system with intraoperative three-dimensional (3D) C-arm computed tomography (CT). Fifteen patients with zygomatico-orbital or isolated orbital/zygoma fractures were enrolled in this prospective cohort. For zygoma reduction, the displacement at five key sutures and the differences between preoperative and intraoperative CT images were compared. For orbital reconstruction, the bilateral orbital volume differences in the anterior, middle, and posterior angles over the medial transitional buttress were measured. Two patients required implant adjustment once after the intraoperative 3D C-arm assessment. On comparing the preoperative and postoperative findings for the zygoma, the average sum of displacement was 19.48 (range, 5.1–34.65) vs. 1.96 (0–3.95) mm (P < 0.001) and the deviation index was 13.56 (10–24.35) vs. 2.44 (0.6–4.85) (P < 0.001). For the orbit, the mean preoperative to postoperative bilateral orbital volume difference was 3.93 (0.35–10.95) vs. 1.05 (0.12–3.61) mm3 (P < 0.001). The mean difference in the bilateral angles at the transition buttress was significantly decreased postoperatively at the middle and posterior one-third. There was no significant difference in orbital volume, angle of the transition zone, and the sum of five zygoma distances between post operative results and preoperative virtual planning. The surgical navigation system with the intraoperative 3D C-arm can effectively improve the accuracy of zygomatico-orbital fracture reconstruction and decrease implant adjustment times.

When giants talk; robotic dialog during thoracolumbar and sacral surgery

BackgroundSpinal trauma patients treated in a specialized hybrid operating room (OR) using two robotic systems communicating during surgery.MethodsRetrospective review of patients with thoracolumbar or sacral fractures who underwent surgical fixation between Jan 2017 to Jan 2020 with robotic-guided percutaneous pedicle screw insertion in the specialized hybrid OR with Robotic flat panel 3D C-arm (ArtisZeego) for intraoperative interventional imaging connected with the robotic-guidance platform Renaissance (Mazor Robotics).ResultsTwenty eight surgeries were performed in 27 patients; 23 with traumatic spinal fractures, 4 with multi-level thoracolumbar compression fractures due to severe osteoporosis. Average patient age 49 (range 12–86). Average radiation exposure time 40 s (range 12–114 s). Average radiation exposure dose 11,584 ± SD uGym2 (range 4454–58,959). Lumber levels operated on were between T5 and S2 (shortest three vertebras and longest eight vertebras). 235 (range 5–11) trajectories were performed. All trajectories were accurate in all cases percutaneous pedicle screws placement was correct, without breach noted at the pedicle in any of the cases. No major complications reported. In all cases, follow-up X-rays showed adequate fracture reduction with restoration.ConclusionsMerging of surgical robotics technologies increases patient safety and surgeon and patient confidence in percutaneous spine traumatic procedures.

Patient radiation exposure from intraoperative computed tomography in spinal surgery

Intraoperative CT imaging is becoming increasingly used, but often little attention is paid to the underlying radiation exposure to the patient. This work showed that the dosimetrically assessed radiation exposure for cervical and lumbar 3D scans with an intraoperative CT is considerably higher than with a 3D C-arm. Therefore, proper selection of the intraoperative 3D imaging system is essential, and further technological developments and dose-saving protocols are warranted to further reduce patient radiation exposure.

Software-Automated Implant Detection for Intraoperative 3D Imaging—First Clinical Evaluation on 214 Data Sets

Previous studies have demonstrated a frequent occurrence of screw/K-wire malpositioning during surgical fracture treatment under 2D fluoroscopy and a correspondingly high revision rate as a result of using intraoperative 3D imaging. In order to facilitate and accelerate the diagnosis of implant malpositioning in 3D data sets, this study investigates two versions of an implant detection software for mobile 3D C-arms in terms of their detection performance based on comparison with manual evaluation. The 3D data sets of patients who had received surgical fracture treatment at five anatomical regions were extracted from the research database. First, manual evaluation of the data sets was performed, and the number of implanted implants was assessed. For 25 data sets, the time required by four investigators to adjust each implant was monitored. Subsequently, the evaluation was performed using both software versions based on the following detection parameters: true-positive-rate, false-negative-rate, false-detection-rate and positive predictive value. Furthermore, the causes of false positive and false negative detected implants depending on the anatomical region were investigated. Two hundred fourteen data sets with overall 1767 implants were included. The detection parameters were significantly improved (p<.001) from version 1 to version 2 of the implant detection software. Automatic evaluation required an average of 4.1±0.4 s while manual evaluation was completed in 136.15±72.9 s (p<.001), with a statistically significant difference between experienced and inexperienced users (p=.005). In summary, version 2 of the implant detection software achieved significantly better results. The time saved by using the software could contribute to optimizing the intraoperative workflow.

Expanding the scope of electromagnetic navigation bronchoscopy-guided transbronchial biopsy and ablation with mobile 3D C-arm Machine Cios Spin®-feasibility and challenges.

Expanding the scope of electromagnetic navigation bronchoscopy-guided transbronchial biopsy and ablation with mobile 3D C-arm Machine Cios Spin®-feasibility and challenges.

Influence de la qualité de la réduction sur les résultats fonctionnels et la qualité de vie après traitement chirurgical des fractures du plateau tibial : étude rétrospective

BackgroundDespite a substantial improvement in the operative treatment of tibial plateau fractures, the surgical procedure remains controversial and is generally challenging, as patients may develop postoperative arthritis and functional impairment of the knee joint. HypothesisIn the surgical treatment of tibial plateau fractures the intraoperative reposition quality has the greatest influence on the postoperative outcome, whereby misalignments of≥2mm lead to a worse result. Patients and methodsForty-one patients with tibial plateau fractures were postoperatively examined. The operative treatment was performed under reduction control using an intraoperative 3D C-arm. The follow-up collective was divided into two groups depending on the intraoperative reduction result. The postoperative results were then evaluated using the following parameters: Lysholm score, Rasmussen score, Tegner score, SF-36 score, range of motion and pain level. ResultsGroup 1 (articular surface incongruencies<2mm) tended to achieve a better result in all scores than group 2 (articular surface incongruencies≥2mm), in the Lysholm score (p=0.039), in the comparison of the range of motion (p=0.012) and the pain level (p=0.039) this was significant. Group 1 achieved an average of 90.71 points (group 2: 78.74) in the Lysholm score. The average range of motion of the knee joint was 138.93° in group 1 (group 2: 127.78°). The average value of the current pain level in group 1 was 1.14 (group 2: 2.63). DiscussionBoth study groups achieved a very good result compared to the available literature. It appears that reduction quality – which can be analyzed with intraoperative 3D imaging – plays the most important role in postoperative quality of life and functional outcome. Intraoperative adjustments of the reduction should therefore be performed on joint surface irregularities with a size above 2mm. Level of evidenceIII; retrospective case control study.

The comparative accuracy and safety of fluoroscopic and navigation-based techniques in cervical pedicle screw fixation: systematic review and meta-analysis.

The goal of this study was to evaluate the comparative accuracy and safety of navigation-based approaches for cervical pedicle screw (CPS) placement over fluoroscopic techniques. A systematic search of the literature published between January 2006 and December 2019 relating to CPS instrumentation and the comparative accuracy and safety of fluoroscopic and intraoperative computer-based navigation techniques was conducted. Several databases, including the Cochrane Library, PubMed, and EMBASE, were systematically searched to identify potentially eligible studies. Data relating to CPS insertion accuracy and associated complications, in particular neurovascular complications, were extrapolated from the included studies and summarized for analysis. A total of 17 studies were identified from the search methodology. Eleven studies evaluated CPS placement under traditional fluoroscopic guidance and 6 studies addressed outcomes following navigation-assisted placement (3D C-arm or CT-guided placement). Overall, a total of 4278 screws were placed in 1065 patients. Misplacement rates of CPS were significantly lower (p < 0.0001) in navigation-assisted techniques (12.51% [range 2.5%-20.5%]) compared to fluoroscopy-guided techniques (18.8% [range 0%-43.5%]). Fluoroscopy-guided CPS insertion was associated with a significantly higher incidence of postoperative complications relating to neurovascular injuries (p < 0.038), with a mean incidence of 1.9% compared with 0.3% in navigation-assisted techniques. This systematic review supports a logical conclusion that navigation-based techniques confer a statistically significantly more accurate screw placement and resultant lower complication rates.

Single-step localization and excision of small pulmonary nodules using a mobile 3D C-arm.

The use of a hybrid operating room equipped with robotic C-arm cone-beam computed tomography for single-step localization and excision of small pulmonary nodules finds high cost barriers. The new generation of 3D C-arm system not only depicts soft tissues with high contrast but also offers a more affordable and sustainable solution. This approach has been chiefly applied in the field of orthopedic surgery. In this case series, we describe the use of a mobile 3D C-arm system for localizing and removing small pulmonary nodules. Between July and September 2020, we identified 14 patients who underwent localization and removal of small pulmonary nodules with a 3D C-arm system. We retrospectively reviewed clinical records to document the feasibility and safety of the procedure. The median tumour size was 7.5 mm [interquartile range (IQR): 5 - 9.75 mm], with a median distance from the pleural surface of 4.2 mm (IQR: 0.5 - 6.45 mm). We successfully visualized all of the pulmonary lesions by intraoperative CT imaging. Localization was achieved in 13 patients, who subsequently underwent complete thoracoscopic resection. The median time required to localize lesions was 41.5 min (IQR: 33.75 - 53.25 min), with a median radiation exposure (expressed through the skin absorbed dose) of 143.45 mGy (IQR: 86.1 - 194.6 mGy). Failure to localize occurred in 1 patient because of pneumothorax caused by repeated needle puncture. All patients were successfully discharged and the median length of stay was 2.5 days (IQR: 2 - 3 days). This case series demonstrates the feasibility of single-step localization and excision of small pulmonary nodules using a mobile 3D C-arm.

Impact of Cone Beam Computed Tomography in Advanced Endovascular Aortic Aneurysm Repair Using Last Generation 3D C-arm

To report the early outcomes of cone beam computed tomography (CBCT) using last generation 3D C-arm in patients undergone advanced endovascular aortic aneurysm repair (AdEVAR) and to identify risk factors that may predict any un-planned procedures. Patients undergone AdEVAR between December 2017 and December 2018 were enrolled. Final CBCT was performed in all patients after digital subtraction angiography. Primary end points were the incidence of any positive findings and the following unplanned procedures intended as any endovascular manoeuvre performed to fix such technical defect. The secondary endpoints were comparison of outcomes between patients with positive findings undergone unplanned procedure (Group A) versus patients without findings (Group B). 132 patients underwent endovascular treatment for aortic aneurysm. Of these, 22 (33%) fenestrated-branched endovascular aneurysm repairs (F-BEVAR), 21 (29%) EVAR with iliac branch devices, 19 (26%) abdominal and 10 (14%) thoracic EVAR were included in the study. Unplanned procedures after CBCT were necessary in 22 patients (31%). Patients in both groups were similar excepted for BMI >25 kg/m2 (55% vs. 26%), hostile iliac anatomy (64% vs. 32%) and previous aortic treatment (73% vs. 32%) (P < 0.05). The odds ratios for unplanned procedure in case of previous aortic treatment was 6.76 (95% CI, 1.97-23.16; P=0.002). The use of CBCT, especially in challenging scenarios, can reveal technical defects and may potentially limit the need for late reintervention. Patients undergone previous aortic surgery should be carefully evaluated and routine CBCT should be performed.

Incidences and Risk factors of Screw-related Superior Facet Articular Surface Violation at L4 and L5 levels in Transforaminal Lumbar Interbody Fusion: Open Surgery Versus Minimally Invasive Techniques.

A retrospective comparative study with radiographic measurements. The aim of this study was to investigate incidences and risk factors of screw-related superior facet articular surface violation (FASV) and optimal pedicle screw angles (PSAs) to avoid FASV at L4 and L5 levels in transforaminal lumbar interbody fusion (TLIF) with either open surgery (OS) or minimal invasive (MIS) techniques with 3D C-arm navigation. L4 to S1 are common levels in TLIF. Adjacent segment diseases (ASD) following TLIF is not uncommon. Screw-related FASV at the superior level is one of the potential risk factors for ASD. In the OS and MIS groups, 111 and 110 screws were included at L4 level, and 114 and 110 screws at L5 level, respectively. Postoperative computed tomography examined screw-related FASV at L3-4 and L4-5 facet levels. The entry point was the location where pedicle screws placed into the facet joints. The OS technique and insertion at the L5 level increased the likelihood of FASV 2.56 and 1.81 times, respec-tively. Multivariate logistic regressions analysis determined PSA was a significant factor associated with FASV. Pearson r between PSA and the distance between midline and entry point was 0.905 (P < .0001). Adding one degree of convergence in PSA led to a mean 0.87 lower odds of an FASV event, regardless of surgical techniques. In 90% of patients in the OS and MIS groups, PSA with FASV was < 11.9° and <15.9° at L4 level, and <15.9° and <21.8° at L5 level, respectively. PSAs played an important role in FASV. MIS allowed greater PSAs and resulted in fewer incidences of FASV. To avoid FASV in 90% of patients, the PSAs might be at least 11.9° and 15.9° at L4 level, and 15.9° and 21.8° at L5 level for OS and MIS techniques, respectively.Level of Evidence: 3.