This retrospective investigation was confirmed through the Hospital Research Ethics Committee, with the need for written patient consent having been waived.
Between January 2015 and December 2020, 137 cases with PNs underwent preoperative CT-guided localization and VATS resection in our hospital. From these cases, 31 (22.6%) underwent localization processes for MPNs. Among these patients, 15 underwent MBL between January 2015 and December 2016, while 16 underwent CL between January 2017 and December 2020. All localization procedures were performed under CT guidance.
Patients eligible for inclusion were those meeting the following criteria: (a) patients with MPNs; (b) each PN was ≥ 4 mm in diameter; (c) each PN was considered to exhibit an intermediate-to-high risk of malignancy on the basis of the clinical-radiological achievements . Cases were not included if they exhibited: (a) typical diffused metastatic MPNs; (b) calcified PNs; (c) PNs that exhibited a reduction in diameter during the follow-up period; and (d) individuals with serious coagulation disorders, active infections, and/or active bleeding.
A chest CT examination (thickness: 1.0–1.25 mm) was used to detect PNs, which were defined as isolated round lesions ≤ 3 cm in the lungs that were not related to atelectasis, pleural effusion, or mediastinal lymphadenopathy . The longest transverse diameter was used to calculate the diameter of each PN. Other preoperative parameters were also recorded, including tumor history, serum neuron-specific enolase, carcinoembryonic antigen, squamous cell carcinoma antigen, and Cyfra21-1 levels.
CT guidance was employed to perform all MBL processes under local anesthesia. Cases were located in an appropriate position based on the position of the target PNs, following which the lung parenchyma was punctured with a 22G needle (Cook, IN, USA) based on the direction of the target PN. Repeated CT scans were used to confirm that the needle tip was appropriately localized, with the direction of the tip being adjusted as appropriate until within 1 cm of the target lesion. Then, 0.1–0.3 ml of MB was injected while smoothly eliminating the needle in a way that MB remained present on the visceral pleura. A one-stage CT-guided procedure was used to localize all PNs, and a repeat CT scan was then executed for the detection of any potential procedure-associated complications.
CT guidance was used to perform all CL procedures under local anesthesia. Needle placement was performed in a manner identical to that used for MBL-based approaches, although a larger 18G needle (Precisa, Roma, Italy) was instead utilized. Subsequently, a coil ( diameter: 0.038 inches, length: 50 mm; Cook) was partially inserted into the parenchyma of the lung. The needle was then cautiously eliminated in a smooth motion in a way that the coil tail kept visible above the visceral pleura. A one-stage CT-guided procedure was used to localize all PNs, and a repeat CT scan was then exerted for the detection of any potential procedure-associated complications.
VATS was generally performed within 3 h following MBL owing to the liquid characteristics of MB, whereas in the CL group VATS was executed within 24 h post-localization.
The visualization of the MB or coil tail above the visceral pleura was used to guide VATS sublobar resection procedures. A wedge-based approach was the standard resection technique, with segmental resection instead being performed when VATS visualization was inadequate to guarantee sufficient surgical margins. The edge of the resected tissue was at least 2 cm from the MB or coil. A one-stage VATS resection procedure was conducted for all target PNs in all patients.
Resected samples of lung parenchymal tissue were sent to our Department of Pathology for rapid pathological assessment. When nodules were diagnosed as being benign, adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), or metastatic lesions, no further resection was exerted. If nodules were instead diagnosed as invasive adenocarcinomas (IAs), additional lobectomy and systematic lymph node dissection were executed. When patients exhibited multiple IAs in different lobes of the lung, lobectomy was conducted for the most advanced PN.
Data pertaining to localization, VATS outcomes, and localization-associated complications were compared between groups. Technical achievement was defined based upon the visualization of MB or of the coil tail, as appropriate, during the VATS procedure [15, 16], with the successful localization of all target PNs being used to define technical success on a per-patient basis . Successful sublobar resection was defined by the presence of the target PN within the resected segment or wedge of the lung parenchyma . Lung hemorrhage was defined based on the detection of new-onset consolidative or ground-glass opacity proximal to the needle tract on CT . Severe hemorrhage was explained by a > 2 cm width of needle tract hemorrhage on CT .
SPSS 16.0 (SPSS, IL, USA) was used for all statistical analyses. Quantitative outcomes are presented as means and were scrutinized through Student’s t-tests, while all other data were presented as N (%) and scrutinized through χ2 tests. P < 0.05 was the threshold of significance for this study.