Necessity of rib head resection for anterior discectomy in the thoracic spine.

<bold>Study Design: </bold>The relation between the rib head and the thoracic disc was investigated anatomically.<bold>Objectives: </bold>To clarify the necessity of rib head resection in thoracoscopic discectomy using the anterior approach.<bold>Summary Of Background Data: </bold>When using the transthoracic anterior approach, the rib head must often be resected. However, there are no reports in which the relation between the rib head and the interspinal disc has been investigated.<bold>Methods: </bold>The distance between the inferior margin of the superior vertebral body and the superior margin proximal to the rib (hereafter, "rib index") was measured.<bold>Results: </bold>The rib index shows negative value in T2-T9 levels, while zero in Tl0 level and positive value T11-T12. The rib index of the fifth to ninth ribs in men was significantly smaller than those in women.<bold>Conclusions: </bold>The surgeon should anticipate full removal of the rib head if operating at T9 and only partial resection below that level. [ABSTRACT FROM AUTHOR]