Computer-assisted Fluoroscopic Navigation Research Articles

Percutaneous Lumbar Pedicle Screw Placement Aided by Computer-Assisted Fluoroscopy-Based Navigation

Institutional review board-approved, prospective, multicenter, comparative study. To assess the accuracy and utility of a computer-assisted fluoroscopic navigation method for percutaneous placement of lumbar pedicle screws compared with conventional fluoroscopic placement. Recent reports indicate that cortical breaches during percutaneous pedicle screw placement can exceed 15%. Computed tomography (CT)- and fluoroscopy-based navigation systems may facilitate increased placement accuracy with reduced radiation exposure and operative times. Patients were alternately assigned to either the Guidance or Control group. The Guidance group underwent lumbar pedicle screw placement using the oblique visualization technique and computer-assisted fluoroscopic navigation. The Control group underwent lumbar pedicle screw placement per standard percutaneous technique aided by fluoroscopy alone. Baseline demographics, visual analog scale (VAS) pain scores, and American Spinal Injury Association scores were obtained preoperatively and in the immediate postoperative period. Fluoroscopy times and guidewire insertion times were recorded intraoperatively. All postoperative CT scans were reviewed by an independent spine surgeon to grade screw placement accuracy. Forty-two patients (210 screws) were assigned to the Guidance group and 34 patients (152 screws) were assigned to the Control group. Use of Guidance resulted in reduced average fluoroscopy usage per pedicle [6.6 sec (SD = 5.1) vs. 9.6 sec (SD 6.2), P < 0.001] and more expedient placement of guidewires per pedicle [3.65 min (SD = 2.31) vs. 4.43 min (SD = 2.56), P = 0.003]. The Guidance group experienced less than half of the breach rate of the Control group (3.0% vs. 7.2%, P = 0.055) and reduced breach magnitudes. None of the breaches resulted in a corresponding neurological deficit or required revision. All patient-reported outcomes were significantly improved after surgery and there were no significant differences in average postoperative VAS scores between treatment groups. Use of Guidance reduces fluoroscopy and insertion times with increased accuracy compared with conventional fluoroscopic methods of percutaneous pedicle screw insertion.

Computer-assisted fluoroscopic navigation of percutaneous spinal interventions

Percutaneous spine procedures may occasionally be difficult and subject to complications. Navigation using a dynamic reference base (DRB) may ease the procedure. Yet, besides other shortcomings, its fixation demands additional incisions and thereby defies the percutaneous character of the procedure. A new concept of atraumatic referencing was invented including a special epiDRB. The accuracy of navigated needle placement in soft tissue and bone was experimentally scrutinised. Axial and pin-point deviations from the planned trajectory were investigated with a CT-based 3D computer system. Clinical evaluation in a series of ten patients was also done. The new epiDRB proved convenient and reliable. Its fixation to the skin with adhesive foil provided a stable reference for navigation that improves the workflow of percutaneous interventions, reduces radiation exposure and helps avoid complications. Percutaneous spine interventions can be safely and accurately navigated using epiDRB with minimal trauma or radiation exposure and without additional skin incisions.

Computer-assisted orthopaedic fracture reduction

Background The goal of this study was to evaluate a new second generation of computer-assisted fluoroscopic navigation software for fracture reduction (SGFR) of long-bone fractures. The new software allows simultaneous tracking of two moving bone fragments. Methods Between 2005–2007, patients with isolated, extra-articular long-bone fracture of either the femur or tibia were considered for computer-assisted fluoroscopic fracture reduction surgery. The operative tasks were: (1) fracture reduction; (2) determination of the entry point, and; (3) Poller screw insertion, when needed. Fracture reduction was achieved by one of two methods: (1) fracture edges or (2) medullary canal recognition. Fracture reduction was considered successful if the guide wire was introduced through the fracture without further radiation. Results We treated 38 patients (27 men and 11 women); with 15 femoral and 23 tibial fractures, with intramedullary nail fixation. In all patients, the point of entry was navigated successfully. In four patients, the insertion of the blocking screw was planned and executed without further radiation. All fractures were successfully reduced using the SGFR system. In nine patients, we used method 1, in 22 patients method 2, and in six a combination of both. The number of fluoroscopic images was dramatically reduced to four to six images. Conclusions Fracture reduction was reliably achievable in all patients using the SGFR. A key conclusion is that only a small number of fluoroscopic images are required. Although timing was not an objective of this study, we believe that there was a noticeable reduction of intraoperative time.

Evaluation der Effizienz des Zero-Dose-C‐Arm-Navigations-Ansatzes

The efficiency and success of computer-assisted fluoroscopic navigation systems mainly depend on the quality of the process of image acquisition: obtaining the correct view of anatomic structures, relative orientation of multiplanar X-ray images and the necessary amount of radiation dose. These systems may be optimised by using a system called zero-dose c-arm navigation (ZDCAN). We investigate whether the available computer-assisted systems may be used to navigate the c-arm before image acquisition to obtain X-ray images with maximised accuracy and minimal radiation exposure. Based on position data of an optical tracking system combined with statistical deformable bone models, ZDCAN is able to generate a real-time preview of expected X-ray images of the lower extremities without using radiation. We performed a cadaver study on six full-body specimens comparing the zero-dose approach to conventional positioning of the c-arm in order to evaluate efficiency and accuracy. Eight users acquired two perpendicular X-ray images of the hip, the knee and the femoral diaphysis. The number of X-ray images required to get a satisfying picture could be reduced to seven using the zero-dose approach; the conventional approach needed 11 images. The mean time did not differ significantly. Regarding the image quality, using ZDCAN quasi-orthogonality could be reached while the conventional approach showed a large variation of the relative orientation. Using ZDCAN, the amount of radiation can be reduced by requiring less X-ray images as well as reaching better accuracy.

Computer-Assisted Fluoroscopic Navigation System for Removal of Distal Femoral Bone Cement in Revision Total Hip Arthroplasty

Removal of the femoral bone cement in revision total hip arthroplasty with a high-powered drill or burr potentially has a risk of damage to the bone, resulting in perforation and fracture of the femur. Recently, we have used a computer-assisted fluoroscopic navigation system for the revision of cemented total hip arthroplasty with a high-powered burr and completely removed the distal femoral bone cement with no complications in 6 cases. Thus, a computer-assisted fluoroscopic navigation system is a useful tool for the improvement of the surgical technique in revision total hip arthroplasty.

Accuracy Over Space and Time of Computer-Assisted Fluoroscopic Navigation in the Lumbar Spine In Vivo

The integration of digital image-guided surgical navigation with C-arm fluoroscopy, known as virtual fluoroscopy (VF), has been shown to enhance the safety of spine surgery in vitro. Few clinical studies have assessed the accuracy of VF during actual spinal surgery, and no studies have investigated variations in accuracy over the course of a series of measurements obtained during operative cases. We sought to study the intraoperative accuracy of VF over time and space during lumbar pedicle screw placement in human patients. Fluoroscopic images of the lumbar spine were obtained, calibrated, and saved to the Stealth Station (FluoroNav) on seven patients undergoing lumbar fusion surgery. The tracking arc was attached to an exposed lumbar spinous process, which was designated the index level. With use of anatomic surface irregularities in the laminae and spinous processes, several points were identified and registered on three different vertebrae directly adjacent to the index level vertebra. Every 15 minutes, throughout the operative case, the probe was brought to each point and the apparent distance from the original location recorded (as measured by the FluoroNav system). Measurements were collected from three vertebral levels adjacent to the index level over a time course of 120 minutes during the operation. At the index, index +1, index +2, and index +3 levels, 89%, 81%, 92%, and 64% of measurements were within <2 mm, whereas 97%, 96%, 97%, and 91% were within <3 mm, respectively. At 15, 30, 45, 60, 75, 90, 105, and 120 minutes, 96%, 89%, 85%, 61%, 85%, 90%, 93%, and 50% of measurements were within <2 mm, whereas 100%, 93%, 100%, 83%, 100%, 90%, 100%, and 100% of measurements were within <3 mm, respectively. The error in millimeters tended to increase as the distance from the index level increased (R = 0.19, P < 0.05) and as operative time increased (R = 0.26, P < 0.01). Calibration studies of intraoperative VF (IoVF) in the lumbar spine documented a reasonable degree of accuracy. The majority of sequential measurements obtained during IoVF in the lumbar spine were within an error range of <3 mm. Our results suggest that the use of VF is a reliable method of verifying the use of anatomic and/or radiographic landmarks for guidance during lumbar pedicle screw placement.

Endoscopic anterior cruciate ligament reconstruction using a computer-assisted fluoroscopic navigation system

BackgroundDuring anterior cruciate ligament (ACL) reconstruction, placement of the reconstructed ligament affects the clinical results. To accomplish accurate and reproducible placement of the tibial bone tunnel, we employed a fluoroscopic navigation system for endoscopic ACL reconstruction. In this study, preciseness of the tibial tunnel placement was evaluated, and the advantages and disadvantages of this navigation system for endoscopic ACL reconstruction are discussed. MethodsAltogether, 16 knees of 16 patients who had undergone ACL reconstruction using this system (navi group) were evaluated regarding the positioning of the tibial tunnel against Blumensaat’s line using X-p and the route of the graft by magnetic resonance imaging (MRI). Another 16 knees of 16 patients who underwent endoscopic ACL reconstruction without the navigation system were the controls (control group). ResultsAt the 1-year follow-up, maximally extended lateral knee X-p revealed that the anterior edge of the tibial tunnel and Blumensaat’s line were almost aligned and that roof impingement was avoided; the T2-weighted MR images showed that the graft was placed close to and parallel to the intercondylar roof in all the knees of the navi group. The ratio of the distance between Blumensaat’s line and the anterior edge of the tibial tunnel at the level of the tibial plateau to the anteroposterior width in fully extended true lateral radiographs was 2.7% ±3.4% in the navi group and 8.4% ±7.4% in the control group. ConclusionsThe computer-assisted fluoroscopic navigation system improves accuracy and decreases dispersion of the tibial tunnel placement against Blumensaat’s line in singlebundle ACL reconstruction. This innovative device renders the reconstruction procedure more reliable, eliminating the problem of skeletal variation among patients. However, the function of this navigation system for femoral tunnel placement is insufficient at present. Further refinement of the system is necessary, and the method of application requires improvement.

Total Hip Arthroplasty in Osteopetrosis Using Computer-Assisted Fluoroscopic Navigation

Hybrid total hip arthroplasty with computer-assisted fluoroscopic navigation was performed on a patient with osteoarthritis due to an autosomal dominant form of osteopetrosis. The surgical procedures were difficult because the bone was extremely hard and brittle with obliteration of the medullary cavity. Especially, preparation of a femoral canal for the stem was technically challenging and required changes from a conventional surgical procedure. Therefore, we used a computer-assisted fluoroscopic navigation system to create the femoral cavity for the stem, and an accurate placement of the prosthesis was achieved. Navigation guidance can be a useful tool when performing arthroplasty in patients with hip osteoarthritis associated with osteopetrosis.

Computer-assisted fluoroscopic navigation of pedicle screw insertion

Computer-assisted fluoroscopic navigation of pedicle screw insertion

Computer-assisted fluoroscopic navigation of pedicle screw insertion An in vivo feasibility study

Accurate placement of pedicle screws is difficult. We evaluated the feasibility and accuracy of pedicle screw insertion assisted by a real-time, 2-dimensional (2D) image-guided navigation system in 12 patients who underwent thoraco-lumbar and/or lumbar stabilization. 66 pedicle screws were inserted either by senior spine surgeons or residents. The accuracy of positioning of the screws was evaluated using postoperative plain radiographs and thin-cut CT. 61 of the 66 screws were inserted successfully. 5 screw insertions showed structural violations: 4 on the medial and 1 on the lateral pedicle wall. The accuracy was higher in the sagittal plane than in the axial plain. There was no difference between the surgical error rates caused by the senior surgeons and the residents. Using computer-assisted 2D fluoroscopic image navigation, it is possible to achieve reliable and accurate pedicle screw insertion during low thoracic and lumbar spinal surgery.