Diagnostic Thoracic Surgical Procedures

Chapter 74 Diagnostic Thoracic Surgical Procedures



Chadrick E. Denlinger, Stephen D. Cassivi, Mark S. Allen


Despite the ever-increasing sensitivity of noninvasive diagnostic modalities, especially in diagnostic imaging, diagnostic thoracic surgical procedures add critical information to the diagnostic workup of patients with diverse thoracic diseases. To provide definitive tissue diagnosis and to assess stage and resectability of chest tumors, the general thoracic surgeon is vital in the diagnostic evaluation of patients.


Common thoracic surgical procedures used for diagnosis include, in order of invasiveness, bronchoscopic, cervical, scalene, and supraclavicular lymph node, pleural, mediastinal, and pulmonary biopsy procedures that involve endoscopic, thoracoscopic, or open surgical approaches. There is a spectrum of invasiveness to these procedures, with exploratory thoracotomy representing the most invasive of these diagnostic techniques. The choice of procedure is guided by the particular clinical question to be answered, as well as specific patient characteristics and, at times, the individual surgeon’s preference and experience. Overall, these procedures provide a high diagnostic yield, with low morbidity and mortality. Complications, although rare, do occasionally occur, and it is therefore incumbent on referring physicians to understand the nature of these procedures, the level of invasiveness, and the relative risk/benefit ratios.



Preoperative Considerations


Except for flexible bronchoscopy, which can be performed using topical anesthesia with minimal sedation, most diagnostic surgical interventions require general anesthesia. The physician first determines the appropriateness of the intervention, because some degree of operative risk is always present. A general contraindication to these procedures is excessive risk from comorbid conditions. The referring physician and ultimately the surgeon must assess the patient’s overall medical status and ability to withstand the proposed procedure. Furthermore, a diagnostic surgical intervention, no matter how minimally invasive, is unnecessary and unwarranted if the findings of the procedure will not influence the treatment plan for the individual patient.



Clinical Application of Diagnostic Thoracic Procedures


The diagnostic thoracic surgical procedures discussed in this chapter have varied applications, with relative advantages and disadvantages (Table 74-1) and are typically used in the following three broad areas:



• Assessment of bronchogenic carcinoma


• Diagnosis of interstitial lung disease


• Sampling of indeterminate pleural, pulmonary, and mediastinal lesions



Table 74-1 Diagnostic Thoracic Surgical Procedures

image



Bronchoscopy


In 1968, Ikeda introduced the first flexible bronchoscope, and over the decades, flexible bronchoscopy has largely supplanted rigid bronchoscopy for diagnostic procedures. Previously, rigid bronchoscopy was the only way to visualize and access the tracheobronchial tree directly. Now, however, the flexible bronchoscope provides access to a greater extent of the airway, can be performed with minimal sedation, and can be routinely performed in the intensive care unit (ICU) as well as the regular patient ward in many hospitals.



Flexible Bronchoscopy


As a diagnostic tool, flexible bronchoscopy offers a relatively noninvasive way to visualize and obtain tissue samples from the airways. The flexible characteristic allows access to subsegmental branches of the tracheobronchial tree. Although flexible bronchoscopy can be done through the endotracheal tube in an anesthetized and intubated patient, this procedure is usually performed with topical anesthesia and conscious sedation. Adjuncts to flexible bronchoscopy continue to evolve, further improving its diagnostic accuracy and utility.


Flexible bronchoscopy not only allows visualization of the tracheobronchial tree, but also provides access for obtaining tissue samples, such as washings, brushings, and bronchoalveolar lavage (BAL) fluid for cytologic and microbiologic analyses. Endobronchial and transbronchial biopsies can be obtained of the airway and lung tissue. In addition, transbronchial needle (Wang) biopsies of mediastinal lymph nodes can be performed through the flexible bronchoscope. This procedure requires a careful evaluation of preoperative images to help blindly pass a needle through the bronchus into the extraluminal lymph node of interest.



Endobronchial Ultrasound


The recent addition of endobronchial ultrasound (EBUS) technology has increased the sensitivity of transbronchial needle biopsies. This special bronchoscope includes the additional feature of a linear ultrasound probe at the end of the scope, which facilitates visualization of lymph nodes outside the airway. Color flow Doppler images also help differentiate lymph nodes from vascular structures. A working channel directs the passage of a transbronchial needle through the region imaged by the ultrasound, to biopsy discrete lymph nodes. EBUS is most frequently used for mediastinal lymph node staging of patients with known or presumed lung cancer. The diagnostic accuracy is similar to that of mediastinoscopy for this indication; two recent prospective studies show a similar diagnostic accuracy of EBUS and mediastinoscopy. Clearly, either procedure has great diagnostic value when performed by experienced clinicians.



Navigational Bronchoscopy


Previously, fluoroscopy was used to assist in directing the bronchoscope and biopsy forceps toward indeterminate peripheral lung lesions. The two-dimensional nature of fluoroscopy and the inability directly to “steer” the biopsy forceps were serious drawbacks of this modality. Navigational bronchoscopy using electromagnetic guidance was recently introduced to improve the yield of bronchoscopic lung biopsies. This technology depends on the construction of a virtual three-dimensional airway using CT images. An electromagnetic field created over the patient’s chest helps to locate and direct a small endoscopic probe toward the lesion in airways beyond visualization with standard bronchoscopy. This technology can be used in combination with a small, radial ultrasound probe to help determine when the bronchoscope has reached the lesion of interest.


Currently the two most common applications of navigational bronchoscopy are to place fiducial markers or to obtain a tissue diagnosis of small lesions located in airways that are distal to the range of visualization. This technology is most useful for lung lesions within the inner third of the lung parenchyma. Lesions located closer to the periphery of the lung can be biopsied using computed tomography (CT)–guided techniques.



Rigid Bronchoscopy


Rigid bronchoscopy is mostly used for therapeutic airway interventions such as airway dilation, laser debridement, tumor debulking, placement of airway stents, or foreign body retrieval (Figure 74-1). The use of the rigid bronchoscope continues to be an important diagnostic tool in special circumstances, such as those requiring a better tactile sense when assessing for possible extrinsic tumor invasion of the airway, or when larger biopsies are sought. It is also indispensable when airway control is in question because of hemoptysis or tumor invasion.


image

Figure 74-1 Rigid bronchoscopy equipment. Top to bottom, Bronchoscope with light cable, straight and right-angled surgical telescopes, biopsy forceps, suction cannula.


Rigid bronchoscopy requires general anesthesia with a muscle relaxant and specific ventilatory strategies. The options most often used include jet ventilation and continuous or intermittent insufflation. In patients with airway control as an overwhelming concern because of an obstructing airway lesion, muscle relaxants are avoided to maintain spontaneous breathing.



Technique


In general, the size of the rigid bronchoscope used for adult men is 8 or 9 mm (outer diameter) and 7 or 8 mm for adult women. Smaller sizes are available for children or smaller adults.


After induction of anesthesia, the patient is positioned supine with the neck extended into the “sniffing” position. Right-handed surgeons use their left thumb to further protect the upper teeth and lips from injury and to serve as the fulcrum in positioning and supporting the bronchoscope throughout the procedure. Protection is also supplemented by use of a rubber tooth guard or saline-soaked gauze sponge. The patient’s eyes are also shielded from inadvertent injury with padded covers for the duration of the procedure.


The bronchoscope is inserted through the right side of the patient’s mouth with the bevel down (Figure 74-2

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Jun 12, 2016 | Posted by in RESPIRATORY | Comments Off on Diagnostic Thoracic Surgical Procedures

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