Abstract
Fluoroscopic guidance is common in interventional pain procedures. In spine surgery, injections are used for differential diagnosis and determination of indication for surgical treatment as well. Fluoroscopy ensures correct needle placement and accurate delivery of the drug. Also, exact documentation of the intervention performed is possible. However, besides the patient, interventional pain physicians, surgeons and other medical staff are chronically exposed to low dose scatter radiation. The long-term adverse consequences of low dose radiation exposure to the medical staff are still unclear. Especially in university hospital settings, where education of trainees is performed, fluoroscopy time and total radiation exposure are significantly higher than in private practice settings. It remains a challenge for university hospitals to reduce the fluoroscopic time while maintaining the quality of education.
Multiple approaches have been made to reduce radiation exposure in fluoroscopy, including the wide spread use of pulsed fluoroscopy, or rarely used techniques like laser guided needle placement systems. The Zero-Dose-C-Arm-Navigation (ZDCAN) allows an optimal positioning of the c-arm without exposure to radiation. For training purposes, relevant anatomical structures can be highlighted for each interventional procedure, so injection needles can be best positioned next to the target area.
The Zero-Dose-C-Arm-Navigation (ZDCAN) module was developed to display a radiation free preview of the expected fluoroscopic image of the spine. Using an optical tracking system and a registered 3D-spine model, the expected x-ray image is displayed in real-time as a projection of the model. Additionally, selected anatomical structures including nerve roots, facet joints, vertebral discs and the epidural space, can be displayed. A seamless integration of the ZDCAN in a c-arm system already used in clinical practice for years could be achieved. For easy use, a tool was developed allowing the admission and use of regular single-use syringes and spinal needles. Accordingly, these can be used as pointers in the sterile area, a sterilization of the whole tool after every single injection is not required. We evaluated the efficiency and accuracy of this procedure compared to conventional fluoroscopically guided interventional procedures. In sawbones of the lumbar spine, facet joint injections (N = 50), perineural injections (N = 46) and epidural injections (N = 20) were performed.
Highlighting the target area in the radiation free preview model, an optimal positioning of the c-arm could be achieved even by unskilled medical staff. The desired anatomical structures could be identified easily in the x-rays taken, as they were displayed in the 3D model aside. As already seen evaluating a previous version of the ZDCAN module for the lower limb, the total number of x-ray images taken could be reduced significantly. Compared to the conventional group, the number of x-ray images required for facet joint injections could be reduced from 12.5 (±1.1) to 5.7 (±1.1), from 5.4 (±1.8) to 3.8 (±1.3) for perineural injections and from 4.1 (±0.9) to 2.1 (±0.3) for epidural injections. Total radiation time was reduced accordingly. Likewise, the mean time needed for the interventional procedure could be reduced from 168.3 s (±19.1) to 131.4 s (±16.8) for facet joint injections, was unchanged from 97.7 s (±26.0) to 104.7 s (±31.0) for perineural injections and from 60 s (±14.9) to 52 s (±7.1) for epidural injections.
The ZDCAN is a powerful tool advancing conventional fluoroscopy to another level. Using the radiation free preview model, the c-arm can easily be positioned to show the desired area. The accentuated display of the target structures in the preview model makes the introduction to fluoroscopy guided interventional procedures easier. This feature might reduce the learning curve to achieve better clinical results with lower radiation dose exposure. Thus, the ZDCAN can be a tool to improve education in university hospital settings for physicians as well as for medical staff while reducing radiation dose exposure in general use.
