Introduction: With the widespread implementation of computed tomography (CT) scans of the chest, more early lung cancers are being detected in the form of small nodules in the lungs. Very small nodules can be difficult to locate during surgery and in order to quickly pinpoint the location of small nodules, methods such as digital palpation, percutaneous puncture, ultrasound or magnetic navigation-guided bronchoscopy have now been developed. However, these methods are all 'invasive', rely on the experience of the doctor, are time consuming and have a high failure rate. Researchers have developed a new positioning method, mainly using 3D printing technology, if you are interested, follow the Antarctic bears!
In June 2022, researchers at the Department of Thoracic Surgery, West China Hospital, Sichuan University, developed a non-invasive nodal localisation technique that enables non-invasive and real-time intraoperative guidance and simultaneous localisation of multiple nodes through a customised, real-life 3D printed 'simulated lung nodal localisation model'. And a case study on this technique has been publicly published, entitled 'Synchronous resection of 12 small pulmonary nodules guided by a non-invasive 3D printed emulation model: A case report' ('In 3D Synchronous resection of 12 small pulmonary nodules guided by a non-invasive 3D printed emulation model: A case report")
Pulmonary and lung nodule modelling
In this case, a 45-year-old woman was admitted to hospital with multiple nodules in her left lung; the individual was asymptomatic. Detection by high resolution computed tomography (HRCT) showed 12 nodules ranging from 0.4 to 1.0 cm in diameter over a 2-year follow-up, with the major nodule growing from 0.7 cm to 1.0 cm. The researchers obtained raw data from the radiology department from the patient's latest HRCT of the chest, set it up in Digital Imaging and Communications in Medicine (DICOM) format, and then imported it into Mimics software V21.0 (Materialize Inc.) for a 3D model reconstruction of the whole lung and lung nodules. Finally, it was imported into a 3D printer and a simulation model of the lung and nodules was created using stereolithography equipment.
△12 nodules information
△Modelling models and printed models of the whole lung and pulmonary nodules
The printed model guides the surgery
The surgeon designed the surgical plan to remove all 12 nodules based on the 3D large print of the mock-up lung nodule localisation model. Video-assisted thoracoscopic surgery (VATS) was performed on nodes 1-7 with a posterior left apical segment resection (blue) and four wedge resections on the remaining nodes in the lobar segment (green), anterior mid-basal segment (red), lateral basal segment (orange) and posterior basal segment (purple) respectively. (Colour areas refer to the figure above)
△ A high-resolution computed tomography (CT) scan of the chest 3 months after surgery showed that no nodules remained in the patient's left lung.
During the procedure, the surgeon was guided by a simulation model to successfully locate the nodules. All 12 nodules were removed, nine of which were identified and marked for pathological examination, while the remaining three nodules were not visually dissected due to their small size. The largest node 11 was pathologically diagnosed as a microinvasive adenocarcinoma (MIA). The researchers sampled the associated lymph nodes and confirmed the absence of tumour pathologically. The entire operation took 200 minutes, with the 12 nodes positioned in just 15 minutes, or an average of 1.25 minutes per node. The patient had his chest tube removed 5 days after surgery and recovered without incident. An HRCT was performed 3 months after the operation and the test proved that there were no residual nodules in the left lung.
Summary and outlook
The use of 3D printed simulation lung models for nodule localisation is non-invasive and convenient. Surgeons can locate small nodules in real time by following the simulation model, which can simply be placed near the thoracoscopic screen as a "navigation map". With the help of a new positioning technique based on 3D printed simulation models, surgeons can easily and precisely locate and remove those multiple ambiguous nodules, often using wedge resection, thus avoiding a second operation and a huge psychological burden for the patient, while preserving lung function as much as possible. The 3D-printed mock lung nodule localisation model also allows the surgeon to remove multiple nodules in a single operation.
