A study of the cutaneous nerves encountered during thoracoplasty.

Study Design: Ten cadavers were dissected to describe the cutaneous branches of the dorsal rami nerves that should be identified and protected throughout the thoracoplasty procedure.

Objective: To identify the anatomic distribution of the cutaneous branches of the dorsal rami in the thoracic spine.

Summary Of Background Data: The last anatomic description of cutaneous branches of the dorsal rami nerves dates back to the early 1900s.

Methods: Ten cadavers were dissected. Each of the branches was followed deeper into the musculature of the back. The Steel 2-incision approach, the Geissele subcutaneous approach, and the subfascial/subtrapezial approach were then carried out on each cadaver.

Results: We determined the course traveled by each of these cutaneous branches of the dorsal rami. Medial branches traverse the paraspinal muscles running dorsally within a few millimeters of the midline before exiting beneath the trapezius. Lateral branches cross the top border of the inferior rib at an average of 6.8 mm from the tip of the transverse process and the lower border of the rib 27 mm from the tip of the transverse process.

Conclusions: Both branches of the dorsal rami nerves are encountered during the posterior approaches used. Medial branches have the best chance for identification and preservation with the subtrapezial approach. Lateral branches can be identified and protected in each of the 3 posterior exposures.