Thoracic splanchnic nerves: implications for splanchnic denervation

Splanchnic neurectomy is of value in the management of chronic abdominal pain. It is postulated that theinconsistent results of splanchnicectomies may be due to anatomical variations in the pattern of splanchnicnerves. The advent of minimally invasive and video-assisted surgery has rekindled interest in the frequencyof variations of the splanchnic nerves. The aims of this study were to investigate the incidence, origin andpattern of the splanchnic nerves in order to establish a predictable pattern of splanchnic neural anatomythat may be of surgical relevance. Six adult and 14 fetal cadavers were dissected (n¯38). The origin of thesplanchnic nerve was bilaterally asymmetrical in all cases. The greater splanchnic nerve (GSN) was alwayspresent, whereas the lesser splanchnic nerve (LSN) and least splanchnic nerve (lSN) were inconsistent (LSN,35 of 38 sides (92%); LSN, 21 of 38 sides (55%). The splanchnic nerves were observed most frequentlyover the following ranges: GSN, T6±9: 28 of 38 sides (73%); LSN, when present, T10±11: (10 of 35 sides(29%); and lSN, T11±12: 3 of 21 sides (14%). The number of ganglionic roots of the GSN variedbetween 3 and 10 (widest T4±11; narrowest, T5±7). Intermediate splanchnic ganglia, when present, wereobserved only on the GSN main trunk with an incidence of 6 of 10 sides (60%) in the adult and 11 of 28sides (39%) in the fetus. The higher incidence of the origin of GSN above T5 has clinical implications,given the widely discussed technique of undertaking splanchnicectomy from the T5 ganglion distally. Thisapproach overlooks important nerve contributions and thereby may compromise clinical outcome. In thelight of these variations, a reappraisal of current surgical techniques used in thoracoscopic splanchnicectomyis warranted