Computed tomography-guided simultaneous coil localization as a bridge to one-stage surgery for multiple lung nodules: a retrospective study

Lung nodules are usually detected by chest computed tomography (CT). Among the lung nodules which were confirmed by pathologic examination, the mean rate of malignancy was approximately 70% [1–4]. Video-assisted thoracoscopic surgery (VATS) has been widely used for diagnostic wedge resection of lung nodules due to its minimal invasive feature [3–8]. Furthermore, the rate of wedge resection of lung nodules successfully increased when it was used along with preoperative localization technique [5].

Among the patients with lung nodules, some were also presented with multiple lung nodules. Except for the typical metastatic nodules, multiple primary lung cancers or precancerosis were also observed in patients with multiple lung nodules [3–8]. When VATS is performed for multiple lung nodules, simultaneous localization for each target nodule is required [7, 8]. Currently, not much information is available about the research on simultaneous multiple localization, although some previous studies included both single and multiple localizations [3–8].

In this study, we evaluated the clinical effectiveness of CT-guided simultaneous coil localization in one-stage VATS wedge resection for multiple lung nodules.

This retrospective study was approved by our institutional review board, that also waived the requirement of informed consent for the use of the patients’ medical data.

Coil localization

All procedures were performed under the guidance of CT. The location in the patient was set according to the position of the nodule. Before localization, a preoperative chest CT scan was performed to confirm the position of the lesions. The puncture pathway was planned according to the position of the target lesions. After administration of local anesthesia with lidocaine, an 18 G coaxial needle (Precisa, Roma, Italy) was punctured into the lung and the tip of the needle was placed within 1 cm near the lesion. A coil of 50 mm length and 0.038- in. diameter (Cook, Bjaeverskov, Denmark) was partially inserted by “leaving-coil-end implantation” method [6] into the lung tissue via the needle sheath. The tail of the coil remained above the visceral pleura depending on the distance between the lesion and the pleura. Finally, the placement of the coil was confirmed through CT examination (Fig. 1) and its complications were further evaluated.

All nodules were simultaneously localized in a one-stage CT-guided procedure.

This study evaluated the feasibility of CT-guided simultaneous coil localization of multiple lung nodules and the clinical effectiveness of coil localization in one-stage VATS wedge resection procedure. Technically, the success rates of simultaneous localization and one-stage VATS wedge resection were 94.7 and 100%, respectively. These results demonstrate that: (a) CT-guided simultaneous coils implantation is a simple and effective method for localization of multiple lung nodules; (b) simultaneous coil localization can effectively guide a one-stage VATS wedge resection procedure.

In lung cancer cases, synchronous multiple lung cancers have been reported in some studies with an incidence rate of 1–8% [9]. Patients with early-stage multiple lung cancers can benefit from multiple VATS resection [10–13]. Theoretically, simultaneous resection is better compared with a two-stage procedure in terms of reducing the risk of disease progression [13].

Accurate diagnosis is critical in the management of lung nodules and a precise pathologic diagnosis is not possible only through image analysis. Although CT-guided cutting needle biopsy can provide a high diagnostic accuracy for lung nodules, it still had a false-negative rate of 5.6–9.6% [14, 15]. Moreover, some small lung nodules may be missed because of technical limitations [16]. In this study, the mean diameter of resected nodules was 7.4 mm, and it was very difficult to perform a biopsy. The diagnostic wedge resection is the gold standard for diagnosis of lung nodules. Furthermore, wedge resection is also considered as a curative treatment for precancerosis, and AIS [3–8]. Some researchers are also of the view that wedge resection could be used for the curative treatment of MIA [3]. In the past, the wedge resection was performed based on the palpation of the lung nodule [5], which was unable to detect some small or sub-solid nodules due to their small size and soft nature. When the wedge resection cannot be performed, the lobectomy should be performed [4], although, unnecessary lobectomy should be avoided to preserve the respiratory function.

For patients with multiple lung nodules, multiple localization can significantly benefit the wedge resection of each nodule [7, 8]. Various methods and materials have been used for preoperative localization including methylene blue, hook-wire, radio-label and coil [3–8]. Tseng et al. [7] and Iguchi et al. [8] used methylene blue and hook-wire, respectively, to localize the multiple lung nodules, with the technical success rates of 99 and 96%, respectively. Correspondingly, the technical success rate in our study was 94.7% and comparable to that of these two studies. However, the earlier methods have some notable disadvantages. Localization of methylene blue is difficult because of its rapid diffusivity [7]. Hook-wire is usually limited by a high incidence of wire dislodgement that may cause pneumothorax, hemorrhage, and chest pain [8]. Radio-label localization guided VATS requires intraoperative fluoroscopy, which brings patients to radiation exposure [17].

Coil localization has been reported in several studies [4–6]. In our study, the coil was inserted by “leaving-coil-end implantation” technique. The end tail of the coil can be easily detected during the VATS. However, this technique requires a well-developed skill and extensive experience. In this study, coil localization failed in one nodule (1/43, 2.3%), but this nodule was also successfully removed by wedge resection based on the successful palpation of the coil. Su et al. [6] also reported 51 cases of entire implantation of the coil and the results demonstrated successful VATS wedge resection in all cases. Furthermore, the coil localization can also help a pathologist to find the lesions in the resected tissue.

In this study, the incidence rate of pneumothorax was 15.8%. This rate was lower than that mentioned in a previous study (89.5%) about hook-wire localization for multiple lung nodules and comparable to that mentioned in a previous study (21.6%) about coil localization for multiple lung nodules [8, 18]. In addition, Li et al. [18] also found no significant difference in pneumothorax (21.6% vs 14.1%, P = 0.179) between multiple and single coil localization groups. Kadeer et al. [19] used a modified hook-wire implantation technique which comprised a row of metal wires, perpendicular insertion, simultaneous release of hook-wire, and a lateral position to localize multiple lung nodules. Compared to the conventional hook-wire insertion, the modified technique can significantly decrease the incident rate of pneumothorax but cannot decrease the incident rate of hemorrhage [19]. Iguchi et al. [8] considered that bilateral hook wire placements should not be performed during one session because bilateral pneumothoraxes may lead to a lethal outcome. However, in this present study, we successfully performed one-stage bilateral coil localization for four patients and no major complication occurred. Thus, we may surmise that one-stage bilateral coil localization is a safe procedure.

Recently, some researchers performed the bronchoscopy-guided dye marking for VATS of lung nodules [20, 21]. This technique may avoid the CT-guided percutaneous transthoracic procedures related complications. However, this technique usually requires real-time fluoroscopic guidance, which can increase the radiation exposure [20].

Based on the pathologic diagnoses from the wedge resection, one patient underwent resection of one lobe due to the invasive adenocarcinoma. In addition, three patients directly underwent VATS lobectomy due to the confirmed diagnosis of lung cancer. The residual nodules were radically resected through wedge resection. This treatment strategy preserved the maximum respiratory function. In one patient, one nodule was diagnosed as invasive adenocarcinoma, but this patient only underwent wedge resection due to the older age. However, during the follow-up, this patient did not develop new lung nodules or distant metastasis.

This study gave encouraging results, although it has some limitations. The first and a major limitation of this study is its retrospective nature, thus, the selected bias definitely existed. Second, there was no control group in this study. Therefore, we could not compare this method to other preoperative localization methods for multiple lung nodules. Third, the period of follow-up was not long. Although no patient developed new lung nodules or distant metastasis, further follow-up results are definitely required.

In conclusion, although further prospective, randomized controlled trials are needed, the results of this study indicate that preoperative simultaneous coil implantation is a safe and simple method for localization of multiple lung nodules and can effectively guide a one-stage VATS diagnostic wedge resection procedure.