Fig. 3.1
Measure the distance between needle tip and outside the parietal pleura
Insert the guide-wire into the needle and push it to the marked location. At this point the distal part of the microcoil has been deployed and coiled in the lung parenchyma.
Hold the guide-wire in place and withdraw the needle slowly. When the needle has been withdrawn beyond the marked location on the guide-wire, withdraw the needle and guide-wire simultaneously. At this point, the microcoil has been fully deployed with the proximal part coiling beyond the parietal pleura and the distal part anchoring in the lung parenchyma (Fig. 3.2).
Fig. 3.2
The microcoil deployed by “tailing method”
Recheck a CT to confirm the position of microcoil and to identify any complications.
3.1.2.4 Operative Procedure
- 1.
Visual examination: explore for the proximal end of the microcoil beyond the visceral pleura (Fig. 3.3).
Fig. 3.3
Trailing part of microcoil on pleural surface
- 2.
Palpation: If the marker has not been found, palpation should be conducted for the implanted microcoil or lesions bypassing the main operating port.
- 3.
Fluoroscopy: For cases with unsuccessful palpation, fluoroscopy should be utilized to find the microcoil.
- 4.
Resection: for cases with successful localization, VATS wedge resection or segmentectomy using endoscopic staplers can be performed
Tips
For Patients with CT-guided microcoil localization, a time duration of 1–3 days between localization procedure and surgery seems to be safe. However, for patients with surgery not on the same day, a chest X-ray is recommended on surgical day to confirm the position of the microcoil and to identify the Late-onset pneumothorax.
3.1.3 Radionucleotide-Guided Localization
3.1.3.1 Equipment
20-guage coaxial needle and 22-guage spinal needle
0.1 ml Technetium Tc-99MAA (macro-aggregated albumin) (0.3 mCi)
Daniel Probe™ (RMD Instruments, Watertown, Massachusetts, USA) (Fig. 3.4)
Fig. 3.4
Daniel™ radioprobe
Navigator GPS™ Control Unit (RMD Instruments, Watertown, Massachusetts, USA) (Fig. 3.5)
Fig. 3.5
Navigator GPS™ control unit
3.1.3.2 Technique of Placing Radionucleotide
On the morning of planned surgery, patient undergoes limited chest CT scan (GE Lightspeed 16 (GE Healthcare, Waukesha, Wisconsin, USA) without intravenous contrast to confirm lung nodule location. The operating surgeon and the interventional radiologist mutually decide on the exact lung site and the best approach angle for radionucleotide placement. The ideal location for placement of the radionucleotide is on the deep side of the nodule relative to the pleural surface. This ensures that if the area of maximum radiation is resected, the nodule will be between the area of maximum radiation and the pleural surface. After confirmation, a 20-guage coaxial needle is positioned in the chest wall just proximal to the pleural cavity. A 22-guage spinal needle is then advanced through the coaxial needle into or adjacent to the lung nodule under CT fluroscopy. Once properly positioned, 0.3 mCi of Technetium Tc-99MAA is then injected (Fig. 3.6). An immediate post-injection scintigram is obtained to confirm intraparenchymal position of the radionucleotide (Fig. 3.7).
Fig. 3.6
Placement of radiotracer
Fig. 3.7
Nuclear medicine scintigram to verify intraparenchymal placement of radionucleotide
3.1.3.3 Operative Procedure
The patient is brought to the operating room once correct radionucleotide placement has been confirmed in radiology. General anesthesia with single-lung ventilation is then induced. Once VATS ports have been placed, a 19-cm-long sterile Daniel™ radioprobe with a 30° angled head and 6 mm shaft is used to localize the area of lung with the maximum radioactive signal. Three thoracoscopic ports are used: one for a 10 mm 30-degree thoracoscope, one for an endoscopic grasper, and one of the gamma probe and endoscopic stapler used sequentially. Once the area of lung with the maximum radioactive signal is identified, that area of lung is grasped and elevated with the endoscopic grasper, and the radioprobe is used to confirm the lesion’s location from multiple angles. The radioprobe is reintroduced as often as necessary during the resection of the lung wedge to assure that the lung tissue being removed contains the maximum radioactive signal. On the wedge containing the lung nodule has been removed, the radioprobe is used to confirm absence or minimal radioactive signal in the remaining lung.
3.2 Results and Discussion
(5)
Department of Thoracic Surgery, Peking University People’s Hospital, No.11 Xizhimen South St., Beijing, 100044, China
(6)
Division of General Thoracic Surgery, Department of Surgery, Mayo Clinic, Rochester, MN, USA
3.2.1 Preoperative Localization
The increased use of chest computed tomography (CT) in lung cancer screening programs and for various clinical applications has led to identification of significant numbers of indeterminate lung nodules. Improved CT technology allows diagnosis of not only more nodules, but also increasingly smaller nodules. Thoracic surgeons are now being called on to evaluate these lesions for the possibility of malignancy, often in the setting of high-risk patients with significant smoking histories. Although short-term follow-up imaging may often suggest either benignity or malignancy, caution should be exercised in accepting a benign diagnosis without tissue confirmation. Additionally, given evidence that tumor size directly impacts survival even within subgroups of stage IA tumors, it makes intuitive sense to attempt to treat potential cancers as early as possible.
We and others have found that small lung nodules, particularly subcentimeter nodules, cannot be reliably biopsied percutaneously [1]. Often, the most expedient and direct path to definitive management of a suspicious indeterminate small pulmonary nodule is to proceed with surgical excisional biopsy. Thoracoscopic surgery carries less morbidity than diagnostic procedures performed through thoracotomy, but is limited by the frequent inability to see or palpate (digitally or instrumentally) small subpleural lesions. To overcome this limitation, several different thoracoscopic nodule localization techniques have been developed and have been reported to improve the ease and accuracy of thoracoscopic biopsy. These include the use of visual markers, such as methylene blue and hook wires, fluoroscopic localization using various radiopaque markers, radiotracer localization techniques, and more recently, thoracic endosonography. All of these techniques have their own advantages and disadvantages, as well as significant learning curves. To date, there is no consensus on the “best” localization technique.
3.2.1.1 Preoperative Technique
Most preoperative localization techniques utilize some form of image guidance, most commonly, CT scanning. Various liquid materials have been used for preoperative localization such as lipiodol [2], methylene blue [3] and barium [4]. However, the success rates of injected dyes may be affected by the density of coloration of the target area and rapid diffusion of these liquids. The contrast method necessitates intraoperative fluoroscopy. One disadvantage of techniques using liquid injectable localizing agents is that unintentional injection of liquid materials into the systemic or pulmonary circulation can cause potentially fatal complications like anaphylactoid reactions or embolisms.
Preoperative localization using hook wires is a common technique and yields reasonable technical success rates [5–7]. However, a relatively higher failure rate due to the dislodgment of the wire has also been reported [8]. Problem of percutaneous hook wire localization besides the dislodgment is the relatively high morbidity rate resulting from wire rigidity such as wire migration. Problematic complications include pneumothorax, pulmonary hematoma, hemoptysis, and air embolism. In a study included 417 patients, 49 % presented with pneumothorax, of which 4.6 % required pumping treatment, 10.3 % presented with hemoptysis and hematoma was 10.3 % while 0.24 % presented with air embolism [6]. One potential limitation of hook wire localization is that the time between hook wire localization and thoracoscopy needs to be minimized in order to reduce the chance of wire dislodgement.
3.2.1.2 Microcoil Localization
Microcoil is a platinum coil designed for embolization of vessel supply in vascular intervention surgery, and have been identified as a useful localizer for preoperatively localization [9, 10]. Microcoil localization may make up for some deficiencies of other techniques. Compared with hook wires, microcoils are not rigid and clinically proven material that can safely be sustained in the human body, so it is not necessary to perform surgery immediately after the localization. Compared with liquid materials, complications caused by intravascular injection and solvent diffusion effects on microcoil localization are not relevant. To be deployed by “tailing method” introduced in the previous section, the microcoil can be detected by visual inspection, palpation, and fluoroscopy during VATS exploration.
We reviewed the data of 98 nodules in our institution and microcoil dislocation were identified on VATS exploration in three patients (3.1 %), resulting a successful localization rate of 96.9 % [11]. The risk factor of microcoil dislocation needed for further study. We suggested a sufficient depth of the implanted microcoil should be ensured and the depth is recommended to be between 1 and 2.5 cm from pleural surface. The types of complications in microcoil localization are similar with hook wire localization, of which pneumothorax usually occurred in lesions adjacent to the pleura or repeated puncture in multiple lesions, while hematoma was more common in lesions with deep location and longer traveling distance of needle. The severity of complications may be less using microcoil compared with hook wire. It is believed that the structural characteristics of the microcoil might help in reducing the severity of complications. The thrombogenic coating of synthetic nylon fibers on the surface of the microcoil may promote blood coagulation of the surrounding lung tissues, block the needle pathway, and decrease the severity of pneumothorax and bleeding caused by the puncture needle damaging the lung tissues, which has been proven in animal experiments [12].
In summary, CT-guided microcoil localization by “trailing method” prior to thoracoscopic resection is a feasible, safe, and effective method for localization of small nodules.
3.2.1.3 Radionucleotide Localization
At our institution, CT-guided radionucleotide injection followed by intraoperative thoracoscopic radioprobe localization is the preferred technique for localizing small lung nodules that we anticipate preoperatively will be difficult to visualize or palpate. Since we began using this technique in October of 2008, we have performed 174 cases (Fig. 3.8). There has been only one technical failure where we were not able to use the radionucleotide placement technique to identify the lung nodule, so our technical success rate is 99.4 %. Two patients (1.1 %) have developed a pneumothorax after radionucleotide placement that necessitate placement of a small pigtail drain prior to surgery. In 65 % of cases, the nodules were solid lesions and in 35 % the nodules were ground glass lesions. The median size of the lung nodule has been 9 mm (range 3, 23 mm). Median depth of the nodule from the chest wall 59 mm (range 5–124 mm). 15.5 % of the nodules were palpable. The indication for surgery in the 174 cases was: rule out lung cancer in 43.5 %, rule out lung metastasis in 39.7 %, lung cancer versus lung metastases in 14.1 %, other in 2.6 %. On final pathology, lung cancer was the diagnosis in 46.2 %, benign etiology in 15.4 %, and metastatic disease in 38.5 %.
Fig. 3.8
Mayo Clinic experience with radionucleotide localization cases
Patients found to have primary lung cancers with adequate lung reserve underwent definitive lobectomy or segmentectomy and nodal staging.
One of the advantages of the radionucleotide localization technique is that it allows marking of lesions anywhere in the lung up to 12 cm deep from the chest wall or 5 cm deep from the pleural surface. The technique does not require intraoperative fluoroscopy, does not require a skilled ultrasonographer in the operating room, and does not require an exotic or expensive radionucleotide. Technetium 99 MAA (Tc99-MAA) is the most widely utilized radionucleotide in nuclear medicine and is widely available. The radioisotope dose required for this technique (0.3 mCi) is only one third the dose of the same isotope used in breast lymphoscintigraphy (1 mCi) and much less than that used for nuclear lung scans (4–5 mCi) and bone scans (10–20 mCi). The half-life of the Tc99 is 8 h, which allows the radionucleotide to be stable once it is placed in the lung for up to 12 h. Furthermore, the radionucleotide emits a gamma particle and does not present any radiation safety hazard to the personnel in the operating room or pathology room. We believe we have overcome the problem of radionucleotide diffusion with the Tc99 MAA solution. Binding the Tc99 to a macro aggregate albumin molecule (MAA) prevents the radionucleotide from dissipating rapidly into the lymphatic system or surrounding parenchyma.
