Involvement of the carina by bronchogenic carcinoma must be assessed with great care by conventional imaging, which includes CT scan of the chest and upper abdomen. Crisp carinal tomograms can be useful to demonstrate the gross extent of the lesion, both within and without the lumen of the trachea, and to make clear the relative portion of airway that seems to be uninvolved by tumor (Figure 8-15). Final bron-choscopic assessment is best made with the Storz Hopkins magnifying telescopes through a rigid broncho-scope. Biopsies of tracheal mucosa proximal to the visible tumor may help to establish the feasibility of resection. Mediastinoscopy is very important for assessment of lymph nodes beyond the information obtained from CT scan. Mediastinoscopy is preferably performed concurrently with a planned resection so that tissue planes and definition of the tumor will not become obscured by inflammation and scar. Should preoperative adjunctive therapy be given following mediastinoscopy because of the finding of N2 lymph nodes, a further en bloc resection at a later date will have to encompass all node-bearing tissue, and accept partly obscured tissue planes. The role of positron emission tomography (PET) scanning in comparison with mediastinoscopy has yet to be clarified, but is likely to remain less exact.
Metastases must be carefully sought by CT examination of the liver and brain and by bone scan. The increased surgical risk of the operation makes these studies mandatory.
Patients being considered for carinal resection for bronchogenic carcinoma must be evaluated for total pulmonary function and distribution of ventilation and perfusion and blood gases. Smoking must have stopped. Sometimes, the involved lung contributes little to total respiratory function if the bronchus is severely obstructed. Cardiac function is also carefully assessed. In a few patients where pneumonectomy would not be tolerated, but where tumor is sufficiently localized, it is possible to perform carinal resection and right upper lobectomy with reimplantation of the middle and lower lobes or of the lower lobe (Figure 8-16). In such a case, involvement of the pulmonary artery is a crucial matter, and angiography may be needed. The final decision to proceed is made only after thorough exploration and before irrevocable surgical steps are
taken. There are special hazards in such complex reconstruction that require precautions in order to avoid excessive anastomotic tension.
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