Thoracoscopic Decompression and Fixation for Thoracic and Thoracolumbar Junction Lesions

35 Thoracoscopic Decompression and Fixation for Thoracic and Thoracolumbar Junction Lesions

Ricky Raj S. Kalra, Meic H. Schmidt, and Rudolf Beisse

35.1 Indications

• Anterior reconstruction of unstable fractures of the thoracic spine and thoracolumbar junction 1

• Posttraumatic and degenerative narrowing of the spinal canal²

• Disk–ligament instability

• Posttraumatic deformity of healed fractures with or without instability³

• Revision surgery (i.e., implant removal, infection, implant failure and loosening)⁴

• Preparation and release of the anterior column in tumor and metastasis

• Sympathectomy for hyperhidrosis⁵

• Protruded disk removal in degenerative disk disease of the thoracic spine⁶

• Resection of metastatic spinal tumors⁷

35.2 Equipment

35.2.1 Trocars

Reusable, flexible, threaded trocars with a diameter of 11 mm are used. Black trocars eliminate reflection. Air insufflation is not required, and thus valves within the trocars are not necessary.

35.2.2 Image Transmission

A high-intensity xenon light source is required to illuminate the thoracic cavity. A rigid, long, 30° endoscope enables positioning of the camera far away from the working portal, thus facilitating undisturbed working and variable adjustment of the angle of vision. The intraoperative view is transmitted onto two or three flat screens.

35.3 Technique

35.3.1 Preoperative Requirements

Pulmonary function testing and assessment for respiratory therapy should be done preoperatively with single-lung ventilation. Bowel preparation is completed to decrease intraabdominal pressure and tension on the diaphragm.

35.3.2 Anesthesia

General anesthesia is used with double-lumen tube intubation and single-lung ventilation. Bronchoscopy confirms tube positioning.

35.3.3 Patient Positioning

The patient is placed in the lateral position, with the approach side determined by great vessels and location of pathology. The patient is stabilized with four supports and a special U-shaped cushion for the legs (Fig. 35.1).

35.3.4 Designing the Entry Portals

Four portals are used: the scope portal, working portal, suction–irrigation portal, and retractor portal. Their location and, in particular, the position of the working portal are crucial for endoscopic surgery.

The lesion is first displayed in the lateral projection (with reference to the patient’s body) under precise adjustment of the image intensifier, and a marker is used to draw the injured spinal section on the lateral abdominal and thoracic wall. Careful attention is paid to correct projection of the vertebrae, whose end plates and anterior and posterior margins should be displayed in the central beam, in sharp focus with no double contour. This marking is taken as the sole reference for subsequent placement of the portals.

The working portal is drawn in directly above the lesion. The trocar for the endoscope is marked either caudal or cranial to the working portal, depending on the height of the lesion, and following the axis of the spine. The distance from the working portal is approximately two intercostal spaces.

The entry points for suction and irrigation and for the retractor are then located ventral to these portals (Fig. 35.1c).

35.3.5 Localization and Port Entry: Approach to the Thoracolumbar Junction

Anterior Reconstruction Landmarks

Landmarks are set under image intensifier control to serve as orientation points for the surgeon and camera operator during the subsequent course of the operation (Video 35.1). For this, the K- wires associated with the implant are used; the K-wires define the later position of the cannulated screws, and they are placed near the end plates between the posterior and central thirds of the vertebra. To achieve this in the thoracolumbar junction region, the psoas muscle must be mobilized in a ventral to dorsal direction, thus avoiding irritation of the fibers of the lumbar plexus.

Positioning of the K-wires near the end plates avoids injury to the segment vessels, and the screws are anchored in a region of higher bone density (Fig. 35.2).

Preparation of the Segment Vessels

The pleura is opened along the connecting line between the K-wires, and the segment vessels are exposed with a Cobb periosteal raspatory. The vessels are mobilized subperiosteally from both sides, ligated twice with titanium clips ventrally and dorsally, and raised slightly with a nerve hook.

The vessels are dissected with the endoscopic hook scissors. The lateral aspects of the vertebral body and the disks are exposed with the raspatory (Video 35.1).