The insertion of the anterior, middle, and posterior scalenus muscles on the first and second ribs, respectively, divides the thoracic inlet into three compartments (Fig. 32.1). The anterior compartment contains the platysma and sternocleidomastoid muscles, the external and anterior jugular veins, the inferior belly of the omohyoid muscle, the subclavian and internal jugular veins and their major branches, and the scalene fat pad. The middle compartment includes the anterior scalene muscle with the phrenic nerve lying on its anterior aspect, the subclavian artery with its primary branches except the posterior scapular artery, the trunks of the brachial plexus, and the middle scalene muscle. Finally, the posterior compartment, which lies posterior to the middle scalene muscle, includes the long thoracic and external branch of the spinal accessory nerves, the posterior scapular artery, the sympathetic chain and stellate ganglion, vertebral bodies, intervertebral foramina, and intercostal nerves.

The anatomic location and the pattern of invasion of the apical lung lesion determine the presenting symptoms and signs. Anterior apical tumors generally present with chest wall or shoulder pain. Hand or arm swelling suggests subclavian vein invasion on the left or brachiocephalic invasion on the right. The phrenic nerve may be involved as it crosses the scalenus anticus muscle. These anterior lesions usually do not involve the brachial plexus.

Tumors invading the middle compartment of the thoracic inlet may present with signs and symptoms related to compression or infiltration of the middle and lower trunks of the brachial plexus, which manifest clinically as pain radiating to the shoulder and upper extremity. Often these tumors spread along the fibers of the middle scalene muscle.

Tumors located posteriorly are usually located in the costovertebral groove and commonly present with some or all the signs and symptoms of the Pancoast-Tobias syndrome, because of the involvement of the C8 and T1 nerve roots, the posterior aspect of the subclavian and vertebral arteries, the sympathetic chain, the stellate ganglion, and prevertebral muscles. These tumors have a propensity to spread along the nerve roots up to the spinal canal through the intervertebral foramina. In addition, vertebral bodies may be involved by direct extension.

Unfortunately, the diagnosis of superior sulcus tumor is often made late because symptoms are not specific, neurologic findings are sometimes absent, and routine imaging of the chest and shoulder are often not revealing. Often symptoms are mistakenly attributed to arthritis or other inflammatory conditions of the shoulder or cervical spine. The radiologic findings can be subtle because these lesions are often hidden behind the first rib and clavicle. Posteroanterior and lateral chest X-ray have little role in evaluation of the superior sulcus tumor. Superb imaging of the lesion and its local extension can be obtained using modern computerized tomographic techniques. High-resolution images with three-dimensional volume averaging allow precise location of extent of the tumor, nerve involvement, and spinal invasion. Specific nerve root or vascular invasion is better assessed by MRI. The easiest way to obtain a tissue diagnosis is by fine-needle aspiration biopsy. Transbronchial biopsy may be considered, but these lesions are so peripheral that this option is rarely useful. If there is a suspicion of extensive pleural invasion or pleural metastases, video-assisted thoracic exploration may be utilized for diagnostic purposes. All patients should undergo a thorough search for hematogenous metastases. Positron emission tomography (PET) imaging should be a routine part of the evaluation to assess both regional lymph node involvement and distant metastatic disease. Because these are T3 lesions, we employ mediastinoscopy and supraclavicular lymph node biopsy in every patient. Patients with N2 or N3 nodal involvement are not candidates for resection. The initial investigation of the potentially operable patient also includes preoperative cardiopulmonary functional tests and other investigations required for any major pulmonary resection.

Preoperative preparation is as for any major pulmonary resection. A double-lumen endotracheal tube or bronchial blocking catheter for left-sided lesions is helpful. Standard monitoring lines include an arterial line in the contralateral radial artery. Two venous lines should be placed to allow for rapid volume replacement as needed.

Different operative approaches are necessary depending upon the location of the primary tumor. The surgeon must be familiar with these various approaches. The goal of the operation is en bloc resection of the upper lobe along with involved ribs and other structures, including transverse processes, the lower roots of the brachial plexus, the stellate ganglion, and the upper dorsal sympathetic chain.

There are three approaches most commonly employed for these lesions. The posterior approach described by Shaw and Paulson is ideal for lesions situated posteriorly. The anterior cervicothoracic approach described by Dartevelle is ideal for the management of anterior lesions. The hemiclamshell approach is less commonly employed but is useful for anterior or posterior lesions.

We believe that whatever approach is selected, an initial cervical exploration is warranted. This is particularly true when a posterolateral Shaw-Paulson resection is anticipated. With the patient supine, shoulders elevated, neck extended, and head turned to the contralateral side, a transverse incision is made immediately above the clavicle. The platysma muscle is divided, as is the clavicular head of the sternomastoid muscle. The supraclavicular fat pad is excised and submitted for frozen-section examination to rule out the involvement of supraclavicular lymph nodes. The phrenic nerve is elevated away from the scalenus anticus muscle, so that the muscle may be divided. This exposes the subclavian artery and the lower roots of the brachial plexus. Anterior displacement of the brachial plexus exposes the scalenus medius muscle, which is then divided, taking care to preserve the long thoracic nerve. By mobilizing and inspecting these structures through a small cervical incision, tumor extent can be assessed and a judgment made regarding the possibility of subsequent complete resection before exposing the patient to the morbidity of a major posterior thoracotomy and rib resection. In addition, this anterior superior mobilization facilitates subsequent dissection and resection through the posterolateral thoracotomy.