CT-guided microcoil localization of pulmonary nodules: the effect of the position of microcoil proximal end on the incidence of microcoil dislocation

Abstract

Objectives: To evaluate the effect of the position of microcoil proximal end on the incidence of microcoil dislocation during CT-guided microcoil localization of pulmonary nodules (PNs). Methods: This retrospective study included all patients with PNs who received CT-guided microcoil localization before video-assisted thoracoscopic urgery (VATS) resection from June 2016 to December 2019 in our institution. The microcoil distal end was less than 1 cm away from the nodule, and the microcoil proximal end was in the pleural cavity (the pleural cavity group) or chest wall (the chest wall group). The length of microcoil outside the pleura was measured and divided into less than 0.5 cm (group A), 0.5 to 2 cm (group B) and more than 2 cm (group C). Microcoil dislocation was defined as complete retraction into the lung (type I) or complete withdrawal from the lung (type II). The rate of microcoil dislocation between different groups was compared. Results: A total of 519 consecutive patients with 571 PNs were included in this study. According to the position of microcoils proximal end on post-marking CT, there were 95 microcoils in the pleural cavity group and 476 in the chest wall group. The number of microcoils in group A, B, and C were 67, 448 and 56, respectively. VATS showed dislocation of 42 microcoils, of which 30 were type II and 12 were type I. There was no statistical difference in the rate of microcoil dislocation between the pleural cavity group and the chest wall group (6.3% vs 7.6%, x2 = 0.18, p = 0.433). The difference in the rate of microcoil dislocation among group A, B, and C was statistically significant (11.9%, 5.8%, and 14.3% for group A, B, and C, respectively, x2 = 7.60, p = 0.008). In group A, 75% (6/8) of dislocations were type I, while all eight dislocations were type II in group C. Conclusions: During CT-guided microcoil localization of PNs, placing the microcoil proximal end in the pleura cavity or chest wall had no significant effect on the incidence of microcoil dislocation. The length of microcoil outside the pleura should be 0.5 to 2 cm to reduce the rate of microcoil dislocation. Advances in knowledge: : CT-guided microcoil localization can effectively guide VATS to resect invisible and impalpable PNs. Microcoil dislocation is the main cause of localization failure. The length of microcoil outside the pleura is significantly correlated with the rate and type of microcoil dislocation. Placing the microcoil proximal end in the pleura cavity or chest wall has no significant effect on the rate of microcoil dislocation.

Outcomes of CT-Guided Deeper Localization Technique for Superficial Pulmonary Nodules

“…Shallow microcoil localization may result in the proximal end of the microcoil being located within the chest wall. The dislocation rate is relatively high when the proportion of microcoils outside the lung increases [15]. When the proximal end of the microcoil is located within the chest wall, the following aspects may be associated with increased dislocation: 1) the chest wall portion of the microcoil is constantly immobile, whereas the intrapulmonary portion moves with respiration and this unsynchronized movement may lead to displacement of the microcoil; 2) if the microcoil is inserted shallowly and the proximal end of the microcoil is placed in the chest wall, the distal end of the microcoil may be pulled out of the lung during lung collapse in VATS.…”

Clinical application of CT-assisted body surface localization combined with intraoperative stereotactic anatomical localization in thoracoscopic lung nodule resection: a single-centre retrospective study

“…Common methods include preoperative CT-guided percutaneous placement of hook wires and microcoils. Nonetheless, these procedures may cause complications such as pneumothorax and haemothorax and increase the risk of displacement [ 12 – 16 ]. Other methods involve CT-guided percutaneous placement of radioactive particles or dyes such as methylene blue, but these also lead to complications and additional challenges [ 17 ].…”