Objective: Video-assisted thoracic surgery (VATS) is an interesting and emerging procedure for diagnosis and treatment of peripheral pulmonary nodules. However, thoracoscopy has limits in the detection of small nodules, below the pleural surface, deep in the lung parenchyma, which cannot be seen as much as palpated. Methods to localize such lesions, including the methylene blue injection or the introduction of a hooked-wire under the radiological vision, have some advantages but a lot of limitations. We are developing a new technique for the detection of pulmonary nodules smaller than 2 cm, deep in the lung parenchyma.
Methods: The technique consisted of a intra-lesional injection of 0.3 ml of solution of 99m Tc-labelled human serum albumin microspheres (5-10 MBq) under the CT-scan guide, 2 h before surgery. During thoracoscopy a 11 mm diameter-collimated probe connected to a gamma ray detector (Scinti Probe MR 100 - Pol. hi.tech., Aquila - Italy), is introduced by a 11.5 mm trocar and the pleural surface of the suspected area was scanned. A hot-spot indicated the presence of the injected nodule and as a consequence, the area to be resected.
Results: from June 1997 to June 1999 we treated 39 patients with small pulmonary nodules. The patients were 27 men and 12 women with a mean age of 60.8 years (range: 13-80). In 19 cases the anamnesis was positive for synchronous or metachronous malignant neoplasm. The mean surgical procedure length was 50 min (range 20-100 min). In all the cases the nodule was resected and the resection margins were pathologically free of tumour. The mean post-operative hospital stay was 3 days (range 2-6 days). Histological examination showed 21 benign lesions and 18 malignant lesions (seven metastases and 11 primary lung cancers). Nine pts with primary lung carcinoma underwent a completion lobectomy by open surgery.
Conclusions: Radiolocalization by gamma-probe allows the detection and exeresis of small nodules in a easy and safe way. Future and predictable advances in radio-marked monoclonal antibodies, as well as in the development of endoscopic beta-detector probe, will offer a more effective method for detection of primary and metastatic tumours, targets of thoracoscopic resections.