Combined Microscopic Tubular and Endoscopic Approach for Calcified Midline Thoracic Disc Herniation: A Bridge to Endoscopic Discectomy.

Symptomatic thoracic disc herniation (TDH) is relatively uncommon and can present with thoracolumbar pain, myelopathy, bladder dysfunction, and motor dysfunction. Midline TDHs and calcified discs are more challenging to access and treat compared to the cervical or lumbar region due to the narrow working corridor around the lungs, ribs, and thoracic spinal cord. Open approaches such as the transthoracic or retropleural approach are particularly morbid. Minimally invasive endoscopic techniques offer decreased tissue dissection and manipulation of the thecal sac but involve a more difficult learning curve. We present a posterolateral approach using a minimally invasive tubular retractor and microscope, which is like minimally invasive techniques many surgeons are already accustomed to using, combined with an endoscope through the tubular retractor. The patient is a 57-year-old female who presented with gait instability due to balance problems and mild bilateral leg "heaviness" and weakness. Her neurologic exam was remarkable for bilateral leg weakness, decreased sensation at the T12 level, hyperreflexia in the bilateral lower extremities, a positive Romberg test, and a wide-based gait. Magnetic resonance imaging revealed disc extrusion at T11-T12 and ligamentum flavum infolding causing mild central canal narrowing, resulting in a mass effect on the cord. We performed a minimally invasive discectomy using a tubular approach combined with an endoscope to access the ventral midline without manipulation of the spinal cord. A combined microscopic and endoscopic may allow surgeons already comfortable with microscopic surgery to master the learning curve of endoscopic techniques.