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Chapter Summary
• Context: Thoracic disc herniation (TDH) is less frequent than cervical or lumbar herniations, but its anatomical intimacy with the spinal cord makes specific presentations exceptionally severe. Normal thoracic kyphosis, restricted canal diameter, and tenuous watershed blood supply to the spinal cord markedly amplify neurological vulnerability. Many thoracic herniations are incidental findings on MRI and remain clinically silent, whereas others produce axial mid-back pain, band-like dermatomal radiculopathy mimicking visceral or abdominal pathology, or progressive compressive myelopathy. Calcification, herniation volume, central versus lateral location, and intradural adhesion or penetration strongly influence surgical complexity. MRI confirms neural compression, while high-resolution CT characterizes bony calcification or ossification. In patients without progressive myelopathy, structured conservative management is appropriate. When progressive neurological deficits occur, surgical corridor selection is individualized. Posterolateral, transthoracic anterior, retropleural, transdural, thoracoscopic, and endoscopic approaches coexist, and the authors emphasize that no single surgical approach is universally suited for all herniation configurations.
• Chapter Objective: To recognize the distinct anatomical and clinical nuances of thoracic disc herniations, understand their natural history and neurological risk factors, interpret complementary MRI and CT findings, and select between conservative care and tailored surgical corridors based on herniation location, calcification, spinal cord compression, and surgical experience.
• An anatomically critical corridorAlthough the thoracic spine possesses limited physiological mobility due to the rib cage, its small spinal canal-to-cord ratio and fragile blood supply (artery of Adamkiewicz) make anterior compressive lesions precarious. Table 44.1 synthesizes anatomical risk factors associated with myelopathy.
• Diverse clinical presentationsMid-back axial pain is common, but lateral herniations can cause sharp radiating intercostal pain that mimics pulmonary, cardiac, or intra-abdominal disease. Bulky central herniations produce gait ataxia, hyperreflexia, lower extremity weakness, and sphincter dysfunction. Tables 44.2 and 44.3 and Figure 44.1 present anatomical and clinical classification systems, emphasizing location, size, and cord compromise.
• Complementary roles of MRI and CTMRI defines spinal cord deformity and intramedullary T2 hyperintensity. CT is indispensable for distinguishing soft herniations from calcified or ossified discs ('giant calcified herniations'), a critical distinction that changes operative complexity and intradural adhesion risks (Figure 44.3).
• Management pathwaysAsymptomatic or non-progressive radicular cases should be observed or managed conservatively. Progressive myelopathy warrants prompt surgical decompression. Surgical approaches must not follow arbitrary personal habit. Traditional posterior laminectomy alone for anterior midline compression is historically contraindicated due to high paraplegia rates.
• Evolution of surgical corridorsFigure 44.4 illustrates posterolateral corridors (transpedicular, transfacet, costotransversectomy, lateral extracavitary). Ventral transthoracic and retropleural approaches provide direct anterior visualization. Full-endoscopic and posterior transdural techniques offer specialized solutions for selected calcified or central lesions. The need for instrumented fusion depends on rib resection, facet disruption, and pre-existing sagittal deformity.
• Clinical Application: In clinical practice, unexplained band-like chest or upper abdominal pain associated with gait unsteadiness or hyperreflexia must prompt thoracic spine MRI. The relative infrequency of thoracic disc herniations often delays diagnosis as patients undergo extensive gastrointestinal or cardiovascular workups. MRI evaluates spinal cord effacement, while CT identifies disc calcification. In the absence of myelopathy, conservative therapy (activity modification, physical rehabilitation, analgesics) has a high success rate. In myelopathic patients requiring surgery, the chosen corridor must permit complete anterior decompression with zero cord retraction. Intraoperative neuromonitoring (MEP/SSEP), precise level localization (using pre-placed pedicle markers or intraoperative CT), and preparedness for dural tears and CSF-pleural fistulas are crucial.
