Patient Position

Patients undergoing thoracolumbar exposures require general anesthesia and appropriate monitoring for comorbidities. The patient is placed in the lateral decubitus position. A right lateral decubitus position with a left-sided approach is preferred to avoid the liver and injury to the inferior vena cava. Most patients are positioned at a 90-degree angle to the table, although 45 to 60 degrees may be preferred in some cases.

An axillary roll is placed under the dependent axilla, and the arms are extended straight across the upper chest, with the upper arm supported. The dependent leg is flexed at the knee, and the other leg is straight and supported by pillows. The kidney rest is elevated, and the table is flexed. A beanbag or tape secures the patient’s hips and shoulders to the table.

Operative Exposure

The rib space to be entered depends on the level of interest. In general, a curvilinear incision is made in the ninth or tenth interspace for access to the lower thoracic spine. The incision starts in the midaxillary line and extends anteriorly and inferiorly toward the umbilicus (Figure 61-1A). It is important to preserve the intercostal neurovascular bundle at the inferior aspect of the rib. Resection of the costal cartilage facilitates the exposure. The external oblique, internal oblique, and transversus abdominis muscles are divided. A plane is developed between the diaphragm and retroperitoneal space along the costal attachment of the diaphragm. Care must be taken with the diaphragm, which originates from the upper lumbar vertebrae, arcuate ligaments, and twelfth ribs and attaches to the lower six ribs and xiphoid. Dividing the diaphragm circumferentially minimizes injury to the phrenic nerve (see Figure 61-1B); this is facilitated with a reticulating intestinal stapler, which reduces bleeding from the diaphragmatic edge and aids in reapproximation of the diaphragm during closure. Use of a Finochietto or Omni retractor for rib separation maximizes visualization. An Omni retractor provides access to the vertebral bodies while protecting vital structures. The Omni post is generally attached to the right side of the table for a left-sided approach. The Omni retractor is positioned across the incision. A wide retractor is placed anteromedially to retract the peritoneum, ureter, and kidney in a medial position. This retractor will serve to protect these structures along with the aorta during vertebral manipulation by the spine surgeon. Three separate right-angle retractors are placed to retract the lung superiorly, the psoas muscle posteriorly, and the iliac vessels inferiorly. Placement of the retractors in these positions ensures adequate exposure and aids in the prevention of inadvertent injuries.

FIGURE 61-1 Thoracolumbar spine exposure. A, Thoracoabdominal incision via the tenth intercostal space. B, Circumferential division of the diaphragm with exposure of the thoracic cavity and retroperitoneal space.

Using blunt dissection, the retroperitoneal space is developed in a retronephric extraperitoneal plane. The retroperitoneal space is entered laterally. The kidney is mobilized anteromedially, along with the peritoneal contents and ureter. The peritoneal sac is dissected free anteriorly, laterally, and finally medially. The aorta and ureter are protected anteromedially. The psoas muscle is identified, and the attachments are mobilized posteriorly off the vertebrae, allowing access to the spine. Segmental vessels are ligated and divided between nonabsorbable ties. Care must also be taken to ligate the iliolumbar vein at the lower lumbar level. Surgeons must be aware of the sympathetic chain, which is lateral to the spine and medial to the psoas muscle. Injury to the sympathetic chain in the lower lumbar spine can result in retrograde ejaculation in men. A spinal needle is inserted into the disk space, and a radiograph is taken to confirm the appropriate vertebral level.

Closure of this exposure begins with reapproximation of the diaphragm. Under direct vision, a chest tube is placed. The ribs are reapproximated, and the thoracic muscles are closed in layers. The retroperitoneal contents should fall into their normal anatomic position. The transversalis fascia and oblique muscle and fascia are reapproximated. The subcutaneous tissue is reapproximated, and the skin is closed. The chest tube is removed when there is no air leak, and the output is less than 150 mL over a 24-hour period.

Complications

Complications of the thoracolumbar approach to the spine can include thoracic, vascular, visceral, neurologic, and urologic injuries. The most common postoperative complications include wound infection, bleeding, pneumonia, and persistent air leak. Care should be taken to avoid iatrogenic, diaphragmatic, and ureteral injuries. Sympathetic chain injuries may also occur and can result in retrograde ejaculation. Bowel injuries result from violation of the peritoneum. In addition, extremity pulses should be assessed preoperatively and postoperatively to ensure that there was no injury, thrombosis, or embolus during arterial manipulation.

Patient Position

Similar to the thoracolumbar approach, the patient is positioned in a modified lateral decubitus position with the right side down to avoid the liver and injury to the vena cava. The hips are rotated 45 degrees. The upper and lower extremities are positioned in a similar fashion to the thoracolumbar approach (Figure 61-2A). The kidney rest is elevated, and the table is flexed to increase exposure between the lower ribs and the iliac crest.

FIGURE 61-2 Anterolateral lumbosacral spine exposure. A, Anterolateral lumbosacral incision from the quadratus lumborum to the lateral border of the rectus muscle. B, Anteromedial retraction of the peritoneum and kidney, lateral retraction of the psoas, and exposure of the segmental vessels for ligation.

Operative Exposure

An oblique incision is made over the eleventh rib from the lateral border of the quadratus lumborum to the lateral border of the rectus abdominis muscle for L1 and L2 exposure (see Figure 61-2A). For L3 to L5, a similar incision is made off of the twelfth rib. Electrocautery is used to divide the subcutaneous tissue, fascia, external and internal oblique, transversus abdominis, and transversalis fascia. The retroperitoneal space is entered laterally.

An Omni retractor is used to facilitate the exposure and is positioned on the table as described previously in the thoracolumbar approach. In a similar fashion, a wide retractor is used to retract the peritoneum and kidney medially while protecting the peritoneum, aorta, and ureter. However, in the lumbosacral approach, one right-angle retractor is used to retract the diaphragm superiorly. The remaining two right-angle retractors are used to retract the psoas muscle posteriorly and the iliac vessels inferiorly.

The peritoneal sac is swept off the anterior and lateral aspects of the abdominal wall, taking care not to violate the peritoneum. The peritoneum and kidney are reflected anteriorly. The peritoneum is dissected off the posterior rectus sheath, and the peritoneum is swept medially off the psoas muscle with Gerota’s fascia. The ureter should fall anteriorly with the peritoneum. The iliac vessels are exposed and protected. The psoas muscle is elevated bluntly off the lumbar vertebrae and retracted posteriorly. The lumbar segmental vessels are ligated as needed for exposure (see Figure 61-2B). Care should be taken to ligate the iliolumbar vein when dissecting the L4 to L5 level; this avoids avulsion of the vein during retraction. A spinal needle is inserted into the disk space, and a radiograph is taken to confirm the appropriate vertebral level.

Closure is performed with reapproximation of the transversalis fascia, oblique muscle, and fascia in layers. The subcutaneous tissue and skin are reapproximated. If the pleura is violated during the exposure, it may be necessary to place a red rubber catheter into the chest cavity to remove air. The defect in the pleura is then closed while the catheter is removed. It is helpful to have the anesthesiologist perform a breath hold after inflating the lungs to minimize air in the chest cavity. If there is any uncertainty about a pneumothorax, a chest tube should be placed.