Techniques for localization of pulmonary nodules for thoracoscopic resection Significant advances in surgical equipment, video monitoring, and endoscopic surgical techniques have expanded the role of thoracoscopy to include pulmonary resection. One limitation of the thoracoscopic technique is the loss of manual palpation to identify the nodule that is either too small or too deep beneath the pleural surface. We describe the techniques used in 300 thoracoscopic pulmonary resections that have aided in identification of pulmonary nodules. These techniques include careful preoperative assessment of the computed tomogram, preoperative injection of methylene blue, or a needle localizing system to identify the nodule. Intraoperative techniques include instrument palpation, digital palpation, and intraoperative ultrasonography. It should be possible to identify the majority of pulmonary nodules at the time of thoracoscopy with these localizing techniques. AIl nodules were successfully identified in our last 200 thoracoscopic resections. (J 'fHORAC CARDIOVASC SURG 1993;106:550-3)
Michael J. Mack, MD,a Hani Shennib, MD,b Rodney J. Landreneau, MD,c and Stephen R. Hazelrigg, MD,d Dallas, Tex., Montreal, Quebec, Canada, Pittsburgh, Pa., and Milwaukee, Wis.
Recent advances in endoscopic surgical equipment, including mechanical stapling devices and laser technology, have expanded the role of thoracoscopy to include thoracoscopic pulmonary resection. 1 Thoracoscopic resection is generally limited to those nodules that are located in or beneath the pleura or, if deeper, are large enough to be detected by instrument palpation.? The inability to use bimanual palpation of the lung as a localization technique necessitates the use of other methods to detect occult nodules. We describe the techniques used during thoracoscopic pulmonary resection to detect occult pulmonary nodules. Patients and methods The generaltechniqueof thoracoscopic pulmonaryresection involves general endotracheal anesthesia with a double-lumen tube to effect ipsilaterallung collapse. The patient is placed in the lateral decubitus position and an initial. 10 mm trocar is placed in the midaxillaryline in the sixthor seventhintercostal From the Sections of Thoracic Surgery Humana Hospital-Medical City Dallas, Dallas, Tex.'; Montreal General Hospital, Montreal, Quebec, Canada"; UniversityofPittsburgh, Pittsburgh, Pa,"; andSt. Luke's Medical Center, Milwaukee, Wis.d Received forpublication Aug. 4, 1992. Accepted forpublication Nov. 9, 1992. Address for reprints: Michael Mack, MD, 7777 Forest Lane, Suite C-202, Dallas, TX 75230. Copyright © 1993 by Mosby-Year Book, Inc. 0022-5223/93 $1.00 +.10 12/1/44191
550
space.General exploratorythoracoscopy is performed to determinethe locationof the target pulmonarynoduleand twoadditionaltrocars are placedunder direct vision, usuallyin the anterior and posterioraxillaryline,to facilitatemanipulation of the lungand placementof eitherendoscopic staplingdevices or laser fiberfor pulmonaryresection. On completion of the procedure, a smallchest tube is placedthrough one of the trocar sites,and the remaining sites are closedwith a subcuticularsuture. Localization techniques
Preoperative assessment. The computed tomogram of the chest is examinedbefore the operation to determinethe likelihood that the localized nodule can be detected at the time of thoracoscopy. If the noduleis pleura based (Fig. 1, A) or subpleural (Fig. 1, B) in locationand I cm or greater in size,the likelihood is great that the nodulewillbe able to be detectedby visualinspection or instrument palpationat the time of exploratorythoracoscopy. Fornodulesthat are deeperthan 1cmbelow the pleuralsurfaceor lessthan 1 em in size,greater difficulty in detectioncan beanticipated(Fig. 2). Carefulexamination ofthe computed tomogram may reveal subtle characteristics that make identification easier.Occasionally, subtlepleuralchanges exist because of puckering of the pleural surface or pleural inflammatorychanges that act as a marker for an underlying pulmonary nodule (Fig. 3). Initial cursory examination of the computed tomogram may indicate a nodule deep within the pulmonary parenchyma. However, examination of soft tissue windows (Fig. 4) may reveal that the nodule is immediately adjacent to a fissure and therefore easily detected by visual inspection at the time of thoracoscopy. In addition,close examinationofthe relationships ofthe target pulmonarynoduletothe chest wall and intrathoracic structures is helpful. Eventhough these relationships change with the collapse of the lung, initial trocar placement can be planned to maximizevisualization of the nodule.
The Journal of Thoracic and Cardiovascular Surgery Volume 106, Number 3
Mack et al. 5 5 I
Fig. 2. Computed tomogram demonstrating nodule that would be difficult to detect at thoracoscopy.
Fig. 1. A, Computed tomogram demonstrating pleura-based nodule easily identified visually at thoracoscopy. B, Subpleural nodule that can be identified by instrument palpation at thoracoscopy.
Needle localization. If it is anticipated from preoperative examination of the computerized tomogram that there will be difficulty locating the nodule at the time of thoracoscopy, then preoperative needle localization is performed.f- 4 The patient is taken to the radiology suite and, under computerized tomographic guidance, a 20-gauge needle from a localizer system (Sadowsky Breast Marking System, Avon, Mass.) is placed percutaneously through the chest wall into the pulmonary nodule. Then 0.05 ml of diluted methylene blue is injected through the localizing needle to stain the subpleural area overlying the nodule.t This staining of the pleural surface serves as an additional aid for locating the nodule and is helpful if the localizing wire becomes inadvertently dislodged. A hook wire is then placed through the localizing needle into the nodule. Although it is ideal to place the wire in the nodule, localization within I cm of the target lesion is sufficient (Fig. 5). On successful localization of the nodule by placement of the hook wire, the patient is transported to the operating room for thoracoscopic resection. An alternative to needle localization preoperatively is fluoroscopic placement in the operating suite. If the nodule is large
enough to be seen fluoroscopically, then the wire can be placed by the radiologist with a portable fluoroscopic unit. This alternative simplifies patient transportation and reduces concern regarding pneumothorax induced by the procedure. Intraoperative techniques. Once exploratory thoracoscopy is undertaken, visual inspection of all visceral pleural surfaces is performed. If pleural involvement by the nodule is present, then the target lesion can almost always be found if the initial trocar has been placed in the general area of the nodule. Increased visualization can be gained by manipulation of the lung with grasping forceps or by the use of a thorascope angled at 30 degrees, which allows visualization of more remote pleural surfaces. Even without pleural involvement, nodules can often be detected by visual inspection. If the nodule is in the subpleural area as the lung collapses, effacement of the lung parenchyma occurs around the nodule. This increased contour of the pleural surface overlying the nodule allows detection of the nodule. This effacement can befurther increased by carbon dioxide insufflation, which enhances the resorptive atelectasis of the lung. If visual inspection is not successful, a blunt grasping instrument is used for palpation of the lung. Subtle characteristics of change in consistency can be detected both visually and tactilely. If the lesion remains undetected after these maneuvers have been performed, partial insufflation of the lung is undertaken. The index finger of the surgeon is placed through one of the trocar sites, and the surface of the lung can be digitally palpated. This technique can be further enhanced by placing a grasping instrument through an adjacent trocar site to bring the lung more easily in apposition to a probing finger. On occasion, placing both index fingers through adjacent trocar sites can allow bidigital palpation of the lung. If a localizing wire has been placed before the operation, its location can easily be determined at the time of thoracoscopy. If the wire becomes inadvertently dislodged, either the methylene blue staining of the subpleural area can be detected or the subtle subpleural hematoma that usually occurs at the entry site of the needle can be identified, Intraoperative ultrasound. Further assistance in identification of localized pulmonary nodules can be obtained by the use of intrathoracic ultrasonography.l Although ultrasonography is not possible when the lung is in the inflated state, the collapsed lung can beeasily examined. With complete collapse of the lung,
552
The Journal of Thoracic and Cardiovascular Surgery September 1993
Macketal.
Fig. 3. Puckering of overlying pleura allows nodule to be visually located at thoracoscopy.
Fig. 5. Computed tomogram showing localizing wire placed adjacent to target nodule. which can be enhanced by carbon dioxide insufflation and placement of fluid in the thoracic cavity to submerge the lung, solidnodules become distinct on sonographic imaging. A 12mm endovaginal or endorectal probe with an end or side transducer operating at 5 MHz is placed through a slightly enlarged trocar site. The underlying nodule can be identified by scanning the suspected lung parenchyma (Fig. 6). This technique can be further used to determine adequate margins of resection by either mechanical stapling or laser resection techniques.
Results
Fig. 4. A, Computed tomogram showing nodule apparently difficult to locate. B, Soft tissue windowdemonstrates that nodule is involvingvisceral pleura in fissure.
We successfully used thoracoscopic pulmonary resection in 300 patients over an I8-month period. Early in our experience, we had difficulty locating nodules on two occasions at the time of thoracoscopy and the operative procedures were converted for open thoracotomy to detect the nodule. Since the development of these techniques, all nodules have been locatable at the time of tho-
The Journal of Thoracic and Cardiovascular Surgery Volume 106, Number 3
Mack et al. 5 5 3
Discussion
Fig. 6. Sonographic image of lung nodule obtained at thoracoscopy. Largearrowshows tumor within leftlower lobe; small arrow shows pericardium. racoscopy. In the last 200 patients,conversion to an open thoracotomy wasnot necessary to identifythe target pulmonary nodule. We used the needle localization techniquein 51 patients.Two patients were not able to tolerate the procedure, and it was aborted. In the remaining 49 patients, dislodgment of the localizing wire occurred either at transport to the operating suite or during the operative procedurein four patients. However, as a result of methylene blue staining, subpleural hematoma from wire placement, or occult pleural changes, all of these nodules couldbe removed. In twoadditionalpatients,the wire failed to adequately localize the nodule. In one patientthe wirewasplacedin the adjacent pericardialfat, and in the other patient the wire crossed a fissure into another lobeof the lung. We werestill able to successfully locatethe nodules in adjacent tissueand removed thoracoscopically. During the procedure, an additional two patients had a pneumothorax, which required an intercostal catheter placement in the radiology department, before the patients were transported to the operating room. The procedure was completed without consequence. We usedintraoperativetransthoracic ultrasonography in nine patients, and the target lesion was successfully identified in all instances. However, in these patients we alsoused the needlelocalizing technique as an indicator to help direct the ultrasonographic examination because we had no previous experience with the technique and thereforewere not certain of its reliability.
Thoracoscopic pulmonary resection of localized nodules can easily be performed with thoracoscopic techniques. A limitingfactor in the resectionof these nodules is the inabilityto locatea nodulethat is 1 em or lessin size and either pleura based or immediately adjacent to the pleura. Becauseof our inabilityto locate two nodulesearlyin our experience, wedeveloped the techniquesoutlined here. With careful attention to the details of these techniques, we were able to successfully locate all target pulmonary nodules in our last 200 patients. As experience growswiththoracoscopic examinationof the lung,wewill becomelessdependenton needlelocalization techniques; greater experience with visualinspection and instrument palpation of the area of lung suspected to contain the occult nodule has given us more confidence in our ability to detect the nodule. We have also been approaching nodules deeper within the lung parenchyma. As experience with laser lung resection grows, we will be more confident about approaching nodules farther than 2 em below the pleural surface. By using the hook wire placed by preoperative localization, we have been able to successfully locate these nodulesat the time of resection. As experiencewith thoracoscopic techniquesand the use of the localizing techniques of this seriesgrow, the majority of occult pulmonary nodules should be identifiable at the time of thoracoscopy. REFERENCES I. Mack MJ, Aronoff RJ, Acuff TE, Douthit MB, Bowman RT,Ryan WHo Present role ofthoracoscopy in thediagnosis andtreatment ofdiseases ofthechest. AnnThorac Surg 1992;54:403-9.
2. Landreneau RJ, Hazelrigg SR, Ferson PF, et a1. Thoraco-
scopic resection of 85 pulmonary lesions. Ann Thorac Surg 1992;54:415-20.
3. Plunkett MB, Peterson MS, Landreneau RJ, Ferson PF, Posner MC. Peripheral pulmonary nodules: preoperative percutaneous needle localization with CTguidance. Radiology 1992;185:274-6. 4. Kerrigan DC, Spence PA, Crittenden MD, Tripp MD.
Methylene blue guidance for simplified resection of a lung lesion. AnnThorac Surg 1992;53:163-4. 5. Mack MJ, Gordon M, Postma TW, et a1. Percutaneous localization of pulmonary nodules for thoracoscopic lung resection. AnnThorac Surg 1992;53:1123-4. 6. Shennib H, BretP. Intraoperative transthoracic ultrasonography: a useful tool to localize a lung lesion during video assisted thoracic surgery. Ann Thorac Surg 1992;55:767-9.