Virtual fluoroscopy: computer-assisted fluoroscopic navigation

STUDY DESIGN: In vitro accuracy assessment of a novel virtual fluoroscopy system. OBJECTIVES: To investigate a new technology combining image-guided surgery with C-arm fluoroscopy. SUMMARY OF BACKGROUND DATA: Fluoroscopy is a useful and familiar technology to all musculoskeletal surgeons. Its limitations include radiation exposure to the patient and operating team and the need to reposition the fluoroscope repeatedly to obtain surgical guidance in multiple planes. METHODS: Fluoroscopic images of the lumbar spine of an intact, unembalmed cadaver were obtained, calibrated, and saved to an ). A was used for the sequential insertion of a light-emitting diode-fitted probe into the pedicles of L1-S1 bilaterally. The trajectory of a "virtual tool" corresponding to the tracked tool was overlaid onto the saved fluoroscopic views in real time. Live fluoroscopic images of the inserted pedicle probe were then obtained. Distances between the tips of the virtual and fluoroscopically displayed probes were quantified using the image-guided computer's measurement tool. Trajectory angle differences were measured using a standard goniometer and printed copies of the workstation computer display. The surgeon's radiation exposure was measured using thermolucent dosimeter rings. RESULTS: Excellent correlation between the virtual fluoroscopic images and live fluoroscopy was observed. Mean probe tip error was 0.97 +/- 0.40 mm. Mean trajectory angle difference between the virtual and fluoroscopically displayed probes was 2.7 degrees +/- 0.6 degrees. The thermolucent dosimeter rings measured no detectable radiation exposure for the surgeon. CONCLUSIONS: Virtual fluoroscopy offers several advantages over conventional fluoroscopy while providing acceptable targeting accuracy. It enables a single C-arm to provide real-time, multiplanar procedural guidance. It also dramatically reduces radiation exposure to the patient and surgical team by eliminating the need for repetitive fluoroscopic imaging for tool placement.     

Minimally-invasive computer-assisted fluoroscopic navigation for kyphoplasty

AIM: The transpedicular placement of a hollow needle into vertebral bodies for kyphoplasty requires utmost accuracy and thereby permanent multiplanar X-ray control. Facing the increasing number of vertebral compression fractures, the aim of this work was the implementation of computer-assistance to optimise the issue. Prior to clinical implementation, experimental trials were undertaken to analyse the quality-improving options of the technique. METHOD: The virtual image of the planning and the puncture were correlated with the postoperative X-ray image of the needle. The real canal in the bone was then correlated with the preoperative planning in a CT-based 3D model and differences were calculated. As a measure of accuracy the deviation of the needle from the ideal intruding vector and the distance between its top and the centre of a predefined target were scrutinised and related to the indications of the navigation system. Operating time, radiation exposure and general applicability were additionally assessed. All data were compared with those of a conventional control group. RESULTS: Planning and navigation could be executed with high accuracy. With an exactly transpedicular approach, neural structures were safely circumnavigated without once missing the target. In the control group the distance fault was up to 9 mm. The navigated drilling differed from the ideal trajectory by 1 degrees to max. 4 degrees. Conventional C-arm control led to a divergence of 4 degrees to 8 degrees . Radiation exposure could be reduced through computer assistance by 76 % to a fourth of the conventionally resulting amount and the pure operating time thereby decreased by 40 %. The inconvenient course of repeated positioning of the C-arm was overcome. CONCLUSION: In challenging cases of deteriorated anatomy and difficult radiomorphologic orientation, especially of the lower thoracic spine, the CAOS-procedure succeeds in finding the optimal pedicular approach to the vertebral body, helps to avoid collateral damage and minimises the overall risk of the procedure. High accuracy and reduced radiation exposure justify the clinical use of fluoroscopic navigation for transpedicular instrumentation.     

Computer-assisted fluoroscopic navigation of percutaneous spinal interventions

Purpose

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.

Methods

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.

Results

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.

Conclusions

Percutaneous spine interventions can be safely and accurately navigated using epiDRB with minimal trauma or radiation exposure and without additional skin incisions.     

Pedicle screw insertion: computed tomography versus fluoroscopic image guidance

Computed tomography image-guided surgery (CTGS) clearly improves the accuracy of pedicle screw insertion. Recent reports claim that a fluoroscopy-guided system (FGS) offered high accuracy and easy application. However, the superiority of either technique remains unclear in clinical application. This study compares the accuracy of pedicle screws installed using CTGS with that of screws installed using FGS. Seventy-four screws inserted using FGS in 13 patients and 76 screws inserted using CTGS in 11 patients were compared. The study population included ten cases of vertebral fracture, five cases of degenerative spondylolisthesis, three cases of spondylolytic spondylolisthesis, two cases of tuberculous spondylitis, two cases of failed earlier back surgery and two case of ankylosing spondylitis with pseudarthrosis. The installed vertebral levels ranged from T8 to S1. Screw positions were assessed with postoperative radiographs and computed tomography. Sixty-nine (93.2%) screws were correctly placed in the FGS group, and seventy-three (96.1%) screws were correctly placed in the CTGS group (P=0.491). The results indicated that both image-guided systems offer high accuracy. However, the fluoroscope image-guided system could be considered the primary tool for lower thoracic and lumbosacral pedicle placement because it enables real-time navigation and does not require a preoperative CT scan.     

Using computerized fluoroscopic navigation to remove pelvic screws

Orthopedic surgeons have recently recognized the benefits of using percutaneous fixation to treat pelvic-ring disruption. Surgical removal of pelvic internal fixation is performed in an anatomically "crowded" area, with no direct vision, and harbors its own risks. Computerized fluoroscopic navigation, which makes implant location easier and reduces radiation exposure, operative time, and soft-tissue damage, can make this procedure short and relatively safe.     

Removal of retained Penrose drain under fluoroscopic guidance

An uncommon complication of Penrose drain usage is retention of the drain by a fascial suture. Removal of a retained Penrose drain can be carried out percutaneously under fluoroscopic guidance.     

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.     

First generation computerized fluoroscopic navigation in percutaneous pelvic surgery

Percutaneous internal fixation of pelvic fractures has gained popularity allowing rapid mobilization with reduced surgical related morbidity; however, this method depends on conventional fluoroscopy, which exposes the patient and the surgeon to a significant amount of radiation. The use of computerized fluoroscopic navigation systems enables the simultaneous use of several radiographic projections. These preliminary fluoroscopic views are taken when the operating team stands at a distance from the radiation source. No further fluoroscopic radiation is used later during the surgical procedure. Computerized fluoroscopic navigation was used in the percutaneous insertion of 45 cannulated screws in 29 patients, including sacroiliac screws, pubic ramus screws, posterior column screws, and a supraacetabular transverse screw. Fluoroscopic verification of screw placement demonstrated a deviation 相似文献   

Renal needle biopsy: a comparative study of fluoroscopic and echographic guidance

The authors report a comparative study of two renal biopsy procedures: fluoroscopic guided biopsy and ultrasound guided biopsy. Results were similar with an interpretability rate of 90%. Morbidity was found to be equal in the two group. However, ultrasound guided biopsy is superior to fluoroscopy guided biopsy in two respects: for patients with renal failure in whom IVP is not possible; for the medical team and patient, who are not exposed to radiation.     

Two-dimensional fluoroscopic navigation in posterior cruciate ligament reconstruction: a preclinical cadaver study

Objectives  

To assess the feasibility and accuracy of frameless stereotactic two-dimensional fluoroscopy-assisted guide pin (GP) placement in posterior cruciate ligament (PCL) reconstruction in human cadavers.     

Controlled endoscopic retrieval of ectopic ureteral catheters using fluoroscopic guidance

The double-J ureteral catheter has been popularized as an ideal internal ureteral stent. Migration of the distal end of the catheter up the ureter, however, can complicate its safe removal. A safe, controlled method of stent extraction is described using a C-arm fluoroscopic unit.     

Injection of the piriformis muscle by fluoroscopic and electromyographic guidance

Background: There is not a universally accepted single technique for injection of the piriformis muscle that has validated exact placement of the needle tip within the piriformis muscle. Objective: We sought a methodology that would precisely document needle placement within the piriformis muscle that is reliable, relatively uncomplicated, and reproducible. Methods: Patients with piriformis syndrome underwent injections of the piriformis muscle under fluoroscopic and electromyographic guidance. This technique used electrophysiological confirmation of needle placement within the piriformis muscle and image-guided identification of the piriformis muscle with radiopaque contrast media under fluoroscopy. Results: Using this methodology, injections on 17 occasions in 11 patients resulted in needle placement within the piriformis muscle.