Use of virtual assisted lung mapping (VAL-MAP), a bronchoscopic multispot dye-marking technique using virtual images, for precise navigation of thoracoscopic sublobar lung resection

Abstract

We have developed a novel bronchoscopic multiple marking technique to assist resection of hardly palpable lung tumors. Because 3-dimensional virtual images were used and multiple markings made on the lung surface to provide "geometric" information, we termed this technique "virtual assisted lung mapping" (VAL-MAP). The safety and efficacy of VAL-MAP were evaluated. Virtual bronchoscopy was used to select 2 to 4 appropriate bronchial branches for marking. Bronchoscopy was conducted with the patient under local anesthesia. A metal-tip catheter was inserted into a selected bronchus and advanced to the pleura. The location of the catheter tip was fluoroscopically confirmed, and 1 mL of indigo carmine was injected. This procedure was repeated to complete all the planned markings. Post-VAL-MAP computed tomography was used to visualize the localization of the multiple markings on 3-dimensional virtual images, which were used as references in the subsequent operation. Of the 95 marking attempts made for 37 tumors in 30 patients, 88 (92.6%) were identified and contributed to the surgery. No clinically evident complications were associated with the procedure. A total of 15 wedge resections and 18 segmentectomies were thoracoscopically conducted, with a successful resection rate of 100%. Multiple markings of the VAL-MAP were complementary, enabling us to achieve complete resection even when 1 of the markings failed. The markings were visible even on interlobar fissures, at the apex, and on the diaphragm, which conventional percutaneous marking can hardly reach. VAL-MAP was safely conducted with satisfactory outcomes in our early experience. Additional confirmation of its safety and efficacy is necessary.