Anatomic Variation of Rami Communicantes in the Upper Thoracic Sympathetic Chain: A Human Cadaveric Study

Hyperhidrosis is secondary to over activation of the sympathetic nervous system and surgical sympathectomy is the treatment of choice when other modalities have failed. This study investigated anatomic variation in the upper thoracic sympathetic chain and associated rami communicantes among cadaveric specimens. It considers the implications of these findings on surgical techniques to treat hyperhidrosis.

The upper 4 thoracic sympathetic ganglia, intercostal nerves, and connecting rami were dissected, measured and mapped in 40 sides of 20 adult human cadavers. Ganglia location was recorded. The incidence, orientation, and distance travelled by rami communicantes was compared across different ganglionic levels and between sides.

The percentage of ganglia located below their associated intercostal space was 6.25% with stellate ganglions present in 70% of specimens and Kuntz fibers noted in 40%. There was a stepwise reduction in incidence of rami from superior to inferior placed ganglia. The number of rami identified across all levels was significantly greater on the right (P = 0.03). The horizontal distance between the sympathetic chain and union of the rami on the intercostal nerves was significantly greater on the right across all levels (P = 0.04).

There was substantial variation in the rami communicantes across the upper 4 ganglia and between right and left sides. Consideration of this variation should be given when planning surgical sympathectomy for hyperhidrosis particularly to avoid symptom recurrence.