Robot-assisted vertebral body augmentation: a radiation reduction tool.

STUDY DESIGN: Retrospective. OBJECTIVE: To assess radiation exposure time during robot-guided vertebral body augmentation compared with other published findings. SUMMARY OF BACKGROUND DATA: Rising incidence of vertebral compression fractures in the aging population result in widespread use of vertebral body cement augmentation with significant radiation exposure to the surgeon, operating room staff, and patient. Radiation exposure leads to higher cancer rates among orthopedic and spine surgeons and patients. METHODS: Thirty-three patients with 60 vertebral compression fractures underwent robot-guided vertebral body augmentation performed by 2 surgeons simultaneously injecting cement at 2 levels under pulsed fluoroscopy. The age of patients was in the range from 29 to 92 (mean, 67 yr). One to 6 vertebrae were augmented per case (average 2). Twenty-five patients had osteoporotic fractures and 8 had pathological fractures. Robotic guidance data included execution rate, accuracy of guidance, total surgical time, and time required for robotic guidance. Radiation-related data included the average preoperative computed tomographic effective dose, radiation time for calibration, registration, placement of Kirschner wires, and total procedure radiation time. Radiation time per level and surgeon's exposure were calculated. RESULTS: Kyphoplasty was performed in 15 patients (1 sacroplasty), vertebroplasty in 13, and intravertebral expanding implants in 5. The average preoperative computed tomographic effective dose was 50 mSv (18-81). Average operative time was 118 minutes (49-350). Mean robotic guidance took 36 minutes. Average operative radiation time was 46.1 seconds per level (33-160). Average exposure time of the surgeons and the operating room staff per augmented level was 37.6 seconds. The execution rate was 99%, with an accuracy of 99%. Two complications (hemothorax and superficial wound infection) occurred. CONCLUSION: The radiation exposure of the surgeon and the operating room staff in a series of robot-assisted vertebral body augmentation was 74% lower than published results on fluoroscopy guidance and approximately 50% lower than the literature on navigated augmentation. LEVEL OF EVIDENCE: 4.

Exposure from the large C-arm versus the mini C-arm using hand/wrist and elbow phantoms.

PURPOSE: This study tests the conventional wisdom that using fluoroscopy under identical geometrical conditions results in less radiation when using the mini C-arm relative to the large C-arm. METHODS: We evaluated the radiation dose for both direct exposure and scatter 2.54 cm outside the intensifier. We used 3 mini and 3 large C-arms in a vertical orientation with the image intensifier below the specimen and the source above. We used 2 specimens: a cadaver hand/wrist and a cadaver elbow. Specimens were tested both directly on the intensifier and on a hand table placed on the intensifier. RESULTS: For the same setup, use of the mini C-arm resulted in direct patient radiation exposure greater than the exposure delivered by the large C-arm. Specifically, exposure using the mini C-arm was 53% to 70% greater than that using the large C-arm. In addition, use of the hand table resulted in exposure 80% to 94% greater compared with placing the specimen directly on the intensifier. In all cases, scatter at 2.54 cm from the intensifier resulted in an average exposure of 1.5% (SD, 0.24%) of the direct beam. Tube current, and therefore machine radiation output, was approximately 13 to 14 times greater for the large C-arm. CONCLUSIONS: Direct radiation exposure to the patient and scatter to the surgeon are minimized when the C-arm is positioned with the intensifier below and the extremity is placed directly on the intensifier. Under identical geometrical conditions with the intensifier below the specimen, the large C-arm with its greater source to image intensifier distance is associated with less radiation exposure than the mini C-arm.

Radiation exposure to the hands from mini C-arm fluoroscopy.

PURPOSE: To quantify the level of radiation exposure to the hands of hand surgeons using intraoperative mini C-arm fluoroscopy and to compare the actual level of exposure with predicted levels and acceptable limits. METHODS: Five hand surgeons were given ring dosimeters to measure radiation exposure to their hands during surgery of the finger, hand, and wrist. A total of 81 rings were analyzed. After the clinical study a phantom was used to measure scatter at close range from the mini C-arm. RESULTS: Surgeons' hands were exposed to an average +/- SD of 20 +/- 12.3 mrem/case. For comparison a chest x-ray results in approximately 20 mrem exposure to the patient. Radiation exposure for the group of hand surgeons ranged from 5 to 80 mrem. Surgeons used an average of 51 +/- 36.9 seconds of fluoroscopy time per case. Exposure time for the group ranged from 6 to 170 seconds. The radiation scatter rate decreases precipitously outside the beam or beyond the radius of the intensifier. An average exposure to the hands of 20 mrem/case suggests that surgeons' hands must be entering the beam and getting direct exposure. CONCLUSIONS: Hand surgeons work close to the beam and as a result their hands potentially are exposed to a nontrivial amount of radiation. We recommend that surgeons who use the mini C-arm use precautions to minimize radiation exposure, particularly to their hands.

Occupational radiation exposure to the surgeon.

Increased use of intraoperative fluoroscopy exposes the surgeon to significant amounts of radiation. The average yearly exposure of the public to ionizing radiation is 360 millirems (mrem), of which 300 mrem is from background radiation and 60 mrem from diagnostic radiographs. A chest radiograph exposes the patient to approximately 25 mrem and a hip radiograph to 500 mrem. A regular C-arm exposes the patient to approximately 1,200 to 4,000 mrem/min. The surgeon may receive exposure to the hands from the primary beam and to the rest of the body from scatter. Recommended yearly limits of radiation are 5,000 mrem to the torso and 50,000 mrem to the hands. Exposure to the hands may be higher than previously estimated, even from the mini C-arm. Potential decreases in radiation exposure can be accomplished by reduced exposure time; increased distance from the beam; increased shielding with gown, thyroid gland cover, gloves, and glasses; beam collimation; using the low-dose option; inverting the C-arm; and surgeon control of the C-arm.