Minimally Invasive Extrapleural Thoracotomy

Anterior approaches to the thoracic and the thoracolumbar region usually provide versatility that is seldom seen with the posterior exposures. They are, however, technically difficult partly due to the unfamiliarity of the surgeons with the anatomical surgical exposure. In a majority of centers, the anterior exposure is generally provided by an “access” surgeon including a general, vascular or a cardiovascular thoracic surgeon.

The anterior thoracotomy exposures were initially developed to manage Potts disease of the spine and gained considerable interest following the lateral thoracotomy incision described by Hodgson and Stock.¹ The lateral thoracotomy is the preferred approach for a majority of the surgeons seeking anterior exposure of the thoracic and the thoracolumbar spine.² The approach can be carried either via a transpleural or retropleural routes depending upon reflection of the parietal pleura. In addition, the approach can be extended into the thoracolumbar region and combined as transpleural-retroperitoneal approach or retropleural-retroperitoneal approach. In the latter, the retroperitoneal space can be accessed by splitting the exposed peripheral segment of the diaphragm, allowing for an extensile access to the retroperitoneum.

The lateral thoracotomy can be performed either in a standard open, a mini-open less invasive manner utilizing self-retaining retractor system, or via a thoracoscopic approach. The choice of approach depends largely upon pathology at hand, as well as surgeons’ familiarity and comfort as these procedures are technically demanding and necessitate thorough understanding of the surgical anatomy.

PATIENT POSITIONING

The patient is placed in a lateral decubitus position and secured to a radiolucent table utilizing hip positioner with sternal pad, sacral pads, and derotation tapes. A true lateral alignment aids the surgeon in maintaining accurate orientation to the spinal canal. The lower leg is flexed at the hip and the knee while the upper leg is extended. Bony prominences are adequately padded (see positioning figures in Chapter 27). A double lumen intubation is preferred to allow for controlled lung deflation allowing better visualization. The side of approach depends upon the level and the site of the pathology. Most surgeons prefer the left lateral decubitus position in order to access T5-L1. The right side thoracotomy can also be used but the liver may impede the visualization in the lower thoracic and thoracolumbar spine. The thoracotomy level is usually at the level of the rib corresponding to two vertebras above the pathology.³ For example, to approach the 12th thoracic vertebra, approach is performed over the 10th rib. The apex of the scoliotic deformity may also govern the side of approach.⁴

Figure 19.1 A: Surgical site markings corresponding to the midaxillary line (arrowhead) and the 10th rib (arrow). B: A 1.5 to 2 inch incision is shown exposing the underlying rib.

TECHNIQUE AND FIXATION

The authors routinely perform thoracotomy in a minimally invasive manner utilizing a selfretaining retractor system (SynFrame, Depuy-Synthes, Jonson & Johnson, Rayhnham, MA). The authors adhere to the principles and objectives of open surgery including adequate and reliable exposure, decompression, instrumentation and reconstruction of the spine in a minimally invasive manner. The level of interest can be marked prior to sterile draping and the surgical field is then draped in a sterile fashion, with wide margins including the lumbar and the thoracic spine. For access to the 12th vertebra, an incision is usually placed over the 10th rib centering the midaxillary line. Usually 1.5 to 2 inches incision provides adequate exposure (Fig. 19.1). The 10th rib is subperiosteally cleaned to free the intercostal muscles along 1.5 to 2 inches rib length with the help of periosteal elevators. Five to ten centimeters of the rib is then resected without violation of the parietal pleura and can be used as a structural autograft (Fig. 19.2).

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