Investigation of Radiological Landmarks Used to Decide the Appropriate Surgical Approach for Upper Thoracic Ventral Degenerative Disorders.

BACKGROUND: Ventral lesions of the upper thoracic spinal cord due to degenerative diseases are rare and often have poor operative outcomes. Anterior decompression for the lesion is difficult because of the local anatomy. This retrospective study aimed to evaluate reproducible anatomical measurements for selecting the best surgical approach for anterior decompression of ventral lesions of the upper thoracic spinal cord.

METHODS: Cases of anterior decompression for ventral lesions of the upper thoracic spinal cord due to degenerative diseases at our institution during 2004-2015 were assessed. Several lines were drawn on magnetic resonance imaging and computed tomography scans of mid-sagittal sections of the upper thoracic spine to evaluate the most optimal approach for treating upper thoracic lesions. A line from the suprasternal notch to the vertebral body (SV line) was accepted as baseline.

RESULTS: The lesion's caudal edge was above the SV line in 10 cases, each of which was treated via an anterior approach without sternotomy. The lesion's caudal edge was below the SV line in seven cases, five of which underwent surgery with the sternum-splitting or transthoracic approach. Other two lesions were approached via an obliquely deviated route without sternotomy. The SV line sometimes changes with the patients' posture alterations.

CONCLUSIONS: SV line, a useful landmark for upper thoracic lesions, is not sufficiently reliable because it changes according to the patient's posture. By leaning in the direction of the surgical microscope, more caudal upper thoracic lesions can be reached than when using the SV line as a surgical landmark.