Laser-guided cervical selective nerve root block with the Dyna-CT: initial experience of three-dimensional puncture planning with an ex-vivo model.

BACKGROUND: Cervical selective nerve root block (CSNRB) is a well-established, minimally invasive procedure to treat radicular cervical pain. However, the procedure is technically challenging and might lead to major complications. The objective of this study was to evaluate the feasibility of a three-dimensional puncture planning and two-dimensional laser-guidance system for CSNRB in an ex-vivo model. METHODS: Dyna-CT of the cervical spine of an ex-vivo lamb model was performed with the Artis Zee® Ceiling (Siemens Medical Solutions, Erlangen, Germany) to acquire multiplanar reconstruction images. 15 cervical nerve root punctures were planned and conducted with the syngo iGuide® laser-guidance system. Needle tip location and contrast dye distribution were analyzed by two independent investigators. Procedural, planning, and fluoroscopic time, tract length, and dose area product (DAP) were acquired for each puncture. RESULTS: All 15 punctures were rated as successful with 12 punctures on the first attempt. Total procedural time was approximately 5 minutes. Mean planning time for the puncture was 2.03 (±0.39) min. Mean puncture time was 2.16 (±0.32) min, while mean fluoroscopy time was 0.17 (±0.06) min. Mean tract length was 2.68 (±0.23) cm. Mean total DAP was 397.45 (±15.63) µGy m(2). CONCLUSION: CSNRB performed with Dyna-CT and the tested laser guidance system is feasible. 3D pre-puncture planning is easy and fast and the laser-guiding system ensures very accurate and intuitive puncture control

Needle tip localization in post-puncture control Dyna-CT images.

<p>Lateral (<b>A</b>), coronal (<b>B</b>), and axial views (<b>C</b>) of the multiplanar reconstructions, as well as (<b>D</b>) three-dimensional rendering of the Dyna-CT of the <i>ex-vivo</i> lamb cervical spine-model demonstrating the location of the needle tip and the trajectory used to access the neural foramen. The needle tip is located in the posterior part of the neural foramen, anatomically well away from the vertebral vessels but directly adjacent to the path of the nerve root.</p

Detailed data for cervical selective nerve root block using Dyna-CT with syngo iGuide® laser-guidance.

1<p>DAP: dose area product.</p

Pre-interventional interventional table positioning and laser-guided puncture.

<p>Correct pre-interventional positioning of the free-floating interventional table shown as three lines properly positioned in the indicated triangle (<b>B</b>). Correct laser-guided puncture along the planned trajectory indicated by the needle in-line with the 2D laser cross (<b>B</b>).</p

Fluoroscopic control images for correct needle positioning.

<p>Bulls’eye view (<b>A</b>) and angulated lateral (<b>B</b>) and oblique (<b>C</b>) views confirming the correct trajectory in-line with the indicated road-map. The positioning of the needle tip centered in the bulls’ eye (<b>A</b>, <b>B</b>, and <b>C</b>) confirming the needle tip in the target area.</p

Three-dimensional puncture planning using syngo iGuide®.

<p>Three-dimensional puncture planning using syngo iGuide® with indication of the planned needle trajectory in two angulated lateral (<b>A</b> and <b>B</b>) views and the axial (<b>C</b>) orientation on the multiplanar Dyna-CT reconstructions of the <i>ex-vivo</i> lamb spine-model. Additionally three-dimensional rendering of the Dyna-CT (<b>D</b>) visualizing the trajectory path. The distance between skin entry and target area is indicated (<b>A</b>, <b>C</b>, and <b>D</b>).</p