Thoracoscopic Approaches for the Treatment of Anterior Thoracic Spinal Pathology
Curtis A. Dickman, MD†
Camilla Mican, MD*
†Division of Neurological Surgery, Barrow Neurological Institute *Division of Cardiothoracic Surgery, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona
Microsurgical approaches for the treatment of pathology of the ventral thoracic spine involving the disk spaces and vertebral bodies can be performed with minimally incisional surgery. Narrow portals are placed in the intercostal spaces to insert working tools and a rigid rod lens endoscope for visualization, magnification, and illumination. Video-assisted thoracoscopic techniques can be used for a variety of spinal surgeries: thoracic microdiskectomies, thoracic vertebrectomies, anterior releases of spinal deformity, interbody fusion, reconstruction of the spine, and placement of internal fixation devices. These techniques have distinct advantages compared to transthoracic and posterolateral approaches to anterior spinal pathology. Small incisions are made in the intercostal spaces, without retracting any ribs. This approach can reduce postoperative pain, shorten the length of hospitalization, improve cosmetic appearances, and allow early resumption of activity. This report describes the surgical techniques involved in this unique operative exposure of the spine.
Key Words: diskectomy, minimally invasive surgery, spine, thoracoscopy, vertebrectomy, video-assisted endoscopic surgery
Minimally invasive surgery has revolutionized almost all areas of surgery. The use of endoscopes permits surgical maneuvers to be performed through small incisions that facilitate a patient’s recovery. Endoscopes have been used for microsurgical magnification and illumination, as arthroscopes in orthopedics; as laparoscopes in general surgery, gynecology and urology; as thoracoscopes in cardiothoracic surgery; and as ventriculoscopes in cranial neurosurgery. They also have been used as diagnostic and therapeutic tools in more traditional endoscopic approaches in otolaryngology, urology, pulmonology, and gastroenterology, among other specialties.
Significant clinical demands exist for minimally invasive surgery. Patients prefer these techniques because they reduce recovery time and have cosmetic benefits. Experience with thoracoscopy versus thoracotomy for diseases of the chest has demonstrated that small incisions that minimize dissection and retraction of the chest wall decrease blood loss and reduce postoperative pain.[1,5-7] These techniques shorten length of stays in the intensive care unit as well as overall hospitalization, hasten recovery times and a patient’s return to work, and lower the costs of medical care.[1,3-5] Already, thoracoscopic surgery has almost replaced thoracotomy in thoracic surgery for a variety of diagnostic and therapeutic purposes.[1,5-7] Biopsy of lesions of the lung and chest wall, pulmonary nodule resections, empyema drainage, resection of adhesions, hemothorax drainage, lymph node biopsy, tumor staging and resection, sympathectomies, and other procedures are regularly performed using thoracoscopy.
Minimally incisional surgery is a more appropriate term than minimally invasive surgery for these operative procedures because the “conventional” operations with extensive anatomical dissections can be performed through the small incisions. This article describes how a variety of surgical procedures used to treat pathology of the anterior thoracic spine can be adapted to a thoracoscopic approach.
Video-assisted thoracoscopic surgery can be used for a variety of spinal indications. The nerve roots and the spinal cord can be decompressed, bone grafts can be placed for interbody fusion and vertebral body reconstruction, and internal fixation devices can be applied to stabilize the spine. Thoracoscopy can be used to perform thoracic sympathectomies, to resect thoracic disk herniations, to biopsy thoracic vertebral body lesions, to release complex spinal curvatures for reduction of scoliosis, to perform vertebrectomies, to resect tumors, to debride infections, and to treat spinal fractures. The thoracic spine is exposed easily by temporarily deflating one lung using a double-lumen endotracheal tube. The collapsed lung creates a large empty working space in the pleural space in which to access the thoracic spine.
Surgeons should be extremely familiar with endoscopic surgical techniques and with the anatomy of the thorax and the mediastinum as well as with the anatomy of the thoracic spine, the spinal cord, and the paraspinal structures. Thoracoscopic spinal surgery ideally is performed in conjunction with a cardiothoracic surgeon experienced in techniques of thoracoscopic surgery. This collaborative approach is recommended to prevent and treat complications and to optimize the benefit to patients.
The thoracic spine can be approached using either a right or a left thoracoscopic access, depending on the location and eccentricity of the pathology and on the regional anatomy. When possible, a right-sided approach is preferable because more spinal surface area is available behind the azygous vein than behind the aorta. The relative position of the great vessels should be inspected on preoperative computed tomography (CT) or magnetic resonance (MR) imaging studies. If exposure is needed at the level of T10 to T12, a left-sided approach is preferred because the liver causes the right diaphragm to ride higher, limiting visibility to the spine. Exposure from T1-T2 to the T12-L1 interspace is possible. The upper thoracic spine is approached from the upper intercostal spaces, near the axillae. The lower thoracic spine is accessed by retracting the diaphragm. The reader should refer to an anatomy textbook for a comprehensive review of thoracic and mediastinal anatomy. The following discussion focuses on details relevant to thoracoscopic spinal surgery and paraspinal anatomy.
Patient Positioning and Operating Room Setup
Video–monitoring screens are placed at several locations throughout the surgical suite to allow the entire surgical team to directly visualize the operative procedure as it is performed.