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The surgical management of thoracic disc disease remains challenging. Outcomes after laminectomy had been poor, and modern posterolateral, lateral, and anterior approaches have evolved to replace this older procedure. Each has its own set of complications, and all are hampered, to varying degrees, by the limited visualization of the ventral disc space and spinal cord during decompression. The authors present their early experience with computer-assisted image guidance as an adjunctive tool for preoperative planning and navigation in the treatment of thoracic disc disease. Five consecutive patients underwent image-guided costotransversectomies between January 1999 and April 2000. The levels of herniation were T8-9 in three and T7-8 and T5-6, respectively, in the other two. There were four centrolateral herniations and one midline herniation. Three discs were soft and two hard. Two patients had previously undergone failed disc excisions. All patients had axial pain and myeloradiculopathies preoperatively. Three were unable to walk.
Four patients enjoyed good or excellent outcomes, with return of ambulation. One patient experienced only mild improvement in her severe paraparesis. Image-guidance was invaluable in planning the corpectomy and aiding visualization in situations in which the dura or disc were obscured; its use allowed successful surgical excisions in the most challenging circumstances.
The surgical management of symptomatic thoracic disc disease remains technically demanding. Laminectomy was used initially to approach these disc herniations, but poor neurological outcomes led to the development of various modern alternatives, including posterolateral, lateral, and anterior approaches. Various modifications of posterior approaches have long been favored by neurosurgeons due to the familiarity of the anatomy and the less invasive nature of the procedure. One significant disadvantage to posterolateral approaches (for example, the transpedicular and transfacet pedicle-sparing approaches) is that they afford limited visualization of and access to the ventral spinal canal and cord. Even with the more lateral trajectory provided by costotransversectomy and its variant, the lateral extracavitary approach, it can be difficult to visualize midline disc herniations.
Anterior approaches -- mainly transthoracic -- have been successfully used, although significant morbidity has been associated with opening the chest. With recent advances in endoscopic technology, the thoracoscopic approach has become more popular; however, it requires special instrumentation and entails a steep learning curve.
The incidence of symptomatic thoracic disc herniations is estimated to be one in 1,000,000 in the general population, and thoracic discectomy procedures constitute only 0.25 to 1% of all disc surgeries. Indeed, a typical neurosurgeon during training may not be exposed to the necessary number of cases to undertake any of these approaches with comfort.
We have chosen to enhance visualization with the lateral approach by using computerized frameless stereotaxy as an adjunct to our costotransversectomy and lateral extracavitary dissections. In this report we describe our preliminary experience with image-guidance technology, which we used successfully to remove symptomatic thoracic disc herniations in five patients.
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