Disc herniation at T1-2. Report of four cases and literature review.

In preparing this paper, the authors reviewed their experiences with four cases of T1-2 disc herniation as well as the medical literature on the subject. Intervertebral thoracic disc herniations are uncommon and high thoracic disc herniations are rare. In the upper third of the thoracic spine, T1-2 is the most common level for disc ruptures. Four cases of disc herniation at T1-2 that caused T-1 radiculopathy are reported in this paper. In reviewing the literature on thoracic disc herniation, the authors found 27 cases at the T1-2 level, 23 of which were lateral disc herniations that produced radiculopathy and four of which were central disc herniations that caused myelopathy. The clinical signs and symptoms of T-1 radiculopathy are similar to those of C-8 radiculopathy; however, distinguishing features can frequently be found on neurological examination. The T-1 radiculopathy usually involves weakness of the intrinsic muscles of the hand. The motor deficit of C-8 radiculopathy involves the intrinsic muscles of the hand and most of the flexors and extensors of the fingers and wrist. The T-1 radiculopathy may produce Horner's syndrome (oculosympathetic paralysis) and diminished sensation in the axilla, which are not found with C-8 radiculopathy. In clinical presentation as well as in treatment, the lateral T1-2 disc herniation resembles a cervical disc herniation, whereas the central T1-2 disc herniation displays the usual appearance of a thoracic disc herniation.