Electromagnetic Navigation Transthoracic Nodule Localization for Minimally Invasive Thoracic Surgery

The main advantage of this technique is that it aids in the perioperative localization of small, deep, and/or sub-solid pulmonary nodules during minimally invasive lung resection. Before beginning the procedure, review prior chest computed tomography or CT imaging to ensure that the patient undergoing the nodule localization has a peripheral pulmonary nodule suitable for minimally invasive thoracic surgery. Then perform a non-contrast chest CT scan with the patient in the lateral decubitus position and the lung ipsilateral to the nodule positioned up to mimic the position during the dye injection.

Obtain both expiratory and inspiratory images to account for nodule movement. On the day of the procedure, use the navigation system planning software to digitally segment the target lesion. If the target lesion is radiographically pure ground glass in nature, the segmentation software may fail to properly identify the lesion.

If that is the case, place a virtual target in the center of the target lesion. Once the target lesion has been successfully marked, use the planning software to delineate the percutaneous site for needle entry. With the patient in the lateral decubitus position, attach three electronic reference point pads on the ipsilateral chest wall to the nodule and at least five centimeters away from the chosen point of entry.

Plug the pads into the electromagnetic navigation system and position the electromagnetic navigation field generator over the reference pads to register the patient within the system. Then use the prompts provided by the electromagnetic navigation system to fine tune the calibration. Once the field generator is in position, use the electromagnetic navigation transthoracic nodule localization platform to take a virtual snapshot of the reference pads.

To generate a data point cloud delineating the extent of the main airways, first insert the proprietary electromagnetic navigation tract disposable scope catheter into the right lumen of the double lumen endotracheal tube. Align the catheter on the main carina and slowly pull back into the trachea until prompted by the system to stop. Then drive the disposable scope catheter into the right lower lung lobe until prompted to stop with another green check mark.

Once the data point collection is halted, transfer the disposable scope catheter from the right lung lumen of the double lumen endotracheal tube into the catheter of the left lung lumen of the tube. Then drive the disposable scope catheter into the left main stem bronchus two to three centimeters proximal to its bifurcation into the left upper and lower lobes. Resume the data collection driving the disposable scope catheter into the left lower lobe until prompted to stop.

Once the full data point cloud has been collected, align a tract percutaneous needle at the chest wall skin entry site using the electromagnetic navigation platform for guidance. Mark the skin at the entry point to the chest cavity taking care that the entry point is just superior to the rib and avoiding any known vasculature or osseus structures. Clean the skin with the 2%chlorhexidine solution for a minimum of 15 seconds and allow the solution to dry for a minimum of 30 seconds.

Drape the field using sterile technique and don sterile gloves and a sterile gown. Subcutaneously inject one to two milliliters of 1%lidocaine at the entry point for local anesthesia. Use a number 10 blade surgical scalpel to make a five millimeter superficial skin incision at the entry site through the epidermis.

Place a sterile 19 gauge electromagnetic needle on the marked entry point. Use the transverse and coronal views on the electromagnetic system screen to adjust the angle of entry so that it lines up with the center of the target lesion. Once the angle of entry is confirmed, stabilize the electromagnetic navigation tract needle against the chest wall.

Firmly advanced the needle through the chest wall while the anesthesia team holds the patient in exhalation. It is critical that the operator properly align the needle with the target lesion in at least two of the three views provided by the electromagnetic navigation system before stabilizing and advancing the needle in a straight downward thrust. Upon reaching the distal side of the target lesion from the chest wall, remove the tract stylet and cover the needle hub with a finger without dislodging the needle.

Next, connect a syringe containing two to three milliliters of the appropriate concentration of methylene blue to the needle and inject 0.5 milliliters of the solution into the target lesion. Then gradually and continuously deposit another 0.5 milliliters of the solution while slowly withdrawing the needle to create a track. When all of the dye has been delivered, use the dye marking to localize and resect the lung nodule by minimally invasive thoracic surgery.

After electromagnetic navigation transthoracic nodule localization as just demonstrated, the localization dye marking can be identified in the deflated lung and diagnostic wedge resection can be undertaken. While attempting this procedure, it is important to remember to ensure a proper registration and needle chest wall placement. This technique will hopefully pave the way for improvements in small nodule resection using minimally invasive surgical methods and in exploring this method's effects on the rate of diagnostic lobectomy and/or conversion to open thoracotomy.