RADIOLOGICAL IMAGING FOR CERVICOTHORACIC JUNCTION AREA

As a simple radiological study, three serial views (anteroposterior [AP] and both lateral views) are commonly used in the cervical spine. At the cervicothoracic junction, the shoulder joint may preclude the correct imaging of the lesion (Fig. 21-1, A). Radiography of this region that allows adequate visualization may be technically difficult to obtain, and in at least 30% of the patients the C7–T1 space is not visualized on the three-view series.¹ The bilateral oblique view and swimmer’s views can be helpful in this situation. In patients for whom the standard AP and lateral view series fails to demonstrate the cervicothoracic junction, swimmer’s views and supine oblique views show the alignment of the vertebral bodies with equal frequency (Fig. 21-1, B). However, supine oblique films are safer, expose patients to less radiation, and are more often successful in demonstrating the posterior elements at the cervicothoracic junction.¹

Fig. 21-1 Radiological study for cervicothoracic junction. A, Lateral view of the cervical spine: C7 corpectomy and anterior instrumentation state. The lower screw is not seen because of the shoulder. B, Swimmer’s view: after the shoulder joint is elevated, the implant level is seen properly.

When the corpectomy is performed at the C7 and T1 levels, the graft position is not evaluated with a simple lateral view (Fig. 21-2, A). With the oblique view, the alignment can be recognized with relative ease (Fig. 21-2, B). For the adequate evaluation of the C7–T1 region, a computed tomography (CT) scan is superior to simple radiography and has several advantages. It shows correct anatomical structures around the transverse process and rib head complex. It also provides sagittal reconstruction, which enables the surgeons to decide the correct position of the graft and instrument. If the CT scan is performed, the correct position of the bone graft and instrument is easily seen with axial and sagittal scans (Fig. 21-2, C and D).

Fig. 21-2 Radiological evaluation of C7–T1 region. A, After C7–T1 corpectomy, bone graft was inserted. The lateral view shows the proximal end of the graft, but the caudal end of the graft is not seen. B, Oblique view shows the alignment of the spine with respect to the bone graft. C, CT scan can provide sagittal reconstruction of the spine, which confirms the location of the graft. D, CT axial view shows that the location of the bone graft is good. It shows the relation of the graft with surrounding structures, such as the spinal cord, rib head, and transverse process.

POSTEROLATERAL PARASCAPULAR APPROACH TO UPPER THORACIC SPINE (TRANSTHORACIC, TRANSPLEURAL THIRD RIB RESECTION APPROACH)

A small thoracotomy through the third rib bed provides access to the retromediastinal space of the cervicothoracic junction (Fig. 21-3). This approach can be accessed with the posterolateral or anterolateral route. The posterolateral approach has several advantages over the anterolateral one. The posterolateral approach can expose the cervical region simultaneously and allow posterior fusion surgery if necessary. It provides a shorter access than the anterior route.

Fig. 21-3 Several kinds of approach to the upper thoracic level: anterior, anterolateral, and posterolateral approach.

Position and Incision

The patient is in the lateral decubitus position with the upper limb of the same side hanging in front of the thorax to encourage the maximum displacement of the scapula (Fig. 21-4). The right side approach is preferred to left side approach below the T4 level because greater vessels can be avoided. At the levels of T1–3 the greater vessels are not encountered, so the approach side is selected according to the lesion side.² A curve commencing at the tip of the spinous process around the posterior angle of the scapula continues along its vertebral border and runs forward 2 or 3 cm above its tip to pass along the line of the fifth rib.¹

Fig. 21-4 Lateral decubitus position and skin incision in posterolateral approach. The incision starts at the tip of the spinous process around the posterior angle of the scapula, along its vertebral border, and runs forward 2 or 3 cm above its tip to pass the line of the fifth rib.

Muscle Dissection

The muscles that connect the spine to the scapula are the trapezius, rhomboid, and levator scapulae. The trapezius muscle is incised along the medial border of the scapula. The division should be made not more than two fingers breadth from the spine to prevent injury of the spinal accessory nerve (Fig. 21-5). Inferior fibers of the trapezius muscle should be transected for the flap to be reflected. The rhomboids are then detached from the vertebral border of the scapula. Then the scapula is mobilized and lifted up, while the surgeon pulls upward and forward with a self-retaining hook. The levator scapulae muscle should be transected for the exposure of the lower cervical region. The entire group of erector spinae muscle and transversospinalis muscle can be dissected off the spinous process, laminae, facets, and transverse processes as a single muscular mass. The insertion of the iliocostalis thoracis muscle also is taken down.