Thoracic splanchnic nerves: implications for splanchnic denervation

Splanchnic neurectomy is of value in the management of chronic abdominal pa in. It is postulated that the inconsistent results of splanchnicectomies ma y be due to anatomical variations in the pattern of splanchnic nerves. The advent of minimally invasive and video-assisted surgery has rekindled inter est in the frequency of variations of the splanchnic nerves. The aims of th is study were to investigate the incidence, origin and pattern of the splan chnic nerves in order to establish a predictable pattern of splanchnic neur al anatomy that may be of surgical relevance. Six adult and 14 fetal cadave rs were dissected (n = 38). The origin of the splanchnic nerve was bilatera lly asymmetrical in all cases. The greater splanchnic nerve (GSN) was alway s present, whereas the lesser splanchnic nerve (LSN) and least splanchnic n erve (ISN) were inconsistent (LSN, 35 of 38 sides (92 %); LSN, 21 of 38 sid es (55 %). The splanchnic nerves were observed most frequently over the fol lowing ranges: GSN, T6-9: 28 of 38 sides (73 %); LSN, when present, T10-11: (10 of 35 sides (29 %); and ISN, T11-12: 3 of 21 sides (14 %). The number of ganglionic roots of the GSN varied between 3 and 10 (widest T4-11; narro west, T5-7). Intermediate splanchnic ganglia, when present, were observed o nly on the GSN main trunk with an incidence of 6 of 10 sides (60 %) in the adult and 11 of 28 sides (39 %) in the fetus. The higher incidence of the o rigin of GSN above T5 has clinical implications, given the widely discussed technique of undertaking splanchnicectomy from the T5 ganglion distally. T his approach overlooks important nerve contributions and thereby may compro mise clinical outcome. In the light of these variations, a reappraisal of c urrent surgical techniques used in thoracoscopic splanchnicectomy is warran ted.