Thoracoscopic Diskectomy

Victor Lo, Alissa Redko, Ashley E. Brown, Daniel H. Kim, and J. Patrick Johnson

33.1 Introduction

Video-assisted thoracoscopic surgery (VATS) emerged to treat spinal disorders in 1993.1,2,3 Current uses of thoracoscopy in spinal procedures include spinal canal decompression (e.g., diskectomy, corpectomy), spinal biopsy, deformity correction, and sympathectomy. The thoracoscopic technique parallels an open thoracotomy procedure in that a ventrolateral approach is taken through the chest cavity, providing a full and direct vertebrolateral view of the vertebra and thecal sac. The benefits of the thoracoscopic procedure include minimal tissue retraction, reduced postoperative pain, and decreased hospital length of stay.^4,5,6 The thoracoscopic approach can also be adapted for instrumentation and fusion if required.⁷ In addition, innovation in intraoperative navigation technology has led to the incorporation of image-guided VATS.^8,9 This chapter describes the indications and procedure for thoracoscopic diskectomy.

33.2 Indications for Thoracic Diskectomy

The incidence of clinically significant thoracic disk herniation is reported to be as low as 1 per million or 0.25 to 0.75% of all ruptured disks.^10,11 Radiculopathy due to thoracic disk herniation typically causes both axial back pain and radicular pain that manifests as paraspinal muscular spasms and bandlike radiating chest wall pain.

Nonsurgical management of these lesions with nonsteroidal anti-inflammatories, epidural steroid injections, and physical therapy has been successful in treating many patients with solely radicular symptoms. Nonsurgical treatment of tolerable thoracic radiculopathy for 3 to 6 months is reasonable given that a large proportion of cases will improve without surgical intervention.

Although there is no consensus regarding thoracic disk removal, surgery is generally reserved for patients who failed conservative treatment of primarily radicular symptoms or who have myelopathy, especially if it is progressive or severe.

Approaches for thoracic diskectomy are dorsolateral (e.g., transpedicular), lateral (e.g., costotransversectomy, lateral extracavitary, parascapular), ventrolateral (e.g., transthoracic/thoracoscopic, retropleural), and ventral (e.g., transsternal). Approach selection depends on the anatomical location of the disk herniation. All soft herniated disks, calcified lateral disks, and mildly calcified centrolateral disks can usually be treated with posterolateral approaches (Fig. 33.1). Centrolateral disks that are densely calcified or certain mildly calcified disks that require any retraction of the spinal cord for diskectomy should be considered for treatment primarily with a ventrolateral or lateral approach (Fig. 33.2). When a transthoracic approach is indicated, one may consider a thoracoscopic approach as well.

Fig. 33.1 (a) Sagittal T1 MRI of the thoracic spine demonstrating a herniated thoracic disk. (b) Axial T1 MRI of the thoracic spine demonstrating a herniated thoracic disk in the ventrolateral aspect of the spinal canal. (c) Axial T2 MRI of the thoracic spine demonstrating a herniated thoracic disk in the ventrolateral aspect of the spinal canal.

33.3 Contraindications to Thoracoscopic Diskectomy

Contraindications include:

• Respiratory insufficiency (i.e., inability to tolerate single-lung ventilation)

• Pleural symphysis

• Failed prior open ventral surgery

• Thoracic empyema

• Previous thoracotomy

• Previous tube thoracostomy

• Bullous lung pathology with reduced lung function

33.4 Imaging for Thoracic Disk Disease

MRI is the optimal modality for assessing the thoracic vertebra, intervertebral disk, and neural elements. MRI can characterize the herniated disk’s location with respect to the spinal canal (i.e., central, paracentral, lateral; Fig. 33.2).

CT defines the bony anatomy and can determine whether the herniated disk is calcified (Fig. 33.3) or the posterior longitudinal ligament is calcified (Fig. 33.4). CT myelography is useful when the patient is unable to tolerate, or has a contraindication to, MRI (Fig. 33.5).

Plain film studies of the thoracic and lumbar spine can be used as an intraoperative reference for localizing the herniated disk.

33.5 Surgical Instruments

The endoscopic equipment needed for a thoracoscopic diskectomy procedure is available in hospital operating rooms where general surgical and gynecological laparoscopy and/or general thoracic endoscopy is performed.¹² The equipment includes:

Fig. 33.2 (a) Sagittal T2 MRI of the thoracic spine demonstrating a thoracic herniated disk. (b) Axial T2 MRI of the thoracic spine demonstrating the herniated thoracic disk in the ventral spinal canal. The anatomical location of this herniated disk suggests it would benefit from the thoracoscopic approach.

Fig. 33.3 (a) Sagittal CT of the thoracic spine demonstrating a large calcified thoracic herniated disk. (b) Axial CT of the thoracic spine showing the large calcified thoracic disk causing canal compression.