Variations in the formation of thoracic splanchnic nerves

The thoracic splanchnic nerves and celiac ganglia play a major role in pain management of upper abdominal disorders, particularly chronic pancreatitis and pancreatic cancer. The variable anatomy of the splanchnic nerves is becoming increasingly important in view of the splanchnicectomy being used more often for relief of pain originating from the upper abdominal viscera. In the present study variations of the roots of origin, formation and course of the splanchnic nerves were observed by using gross dissections of eighty-eight sides of thirty-four adult and ten foetal cadavers. The greater splanchnic nerve was found on both sides of all the adult cadavers as well as foetal specimens (100%). The lesser splanchnic nerve was found in 95.45% (84 sides) of the sides. The lesser splanchnic nerve was found to be absent unilaterally in four adult cadavers (two each of right and left sides). The least splanchnic nerve was found in 67.5% of the sides. Excepting a right side of one adult female cadaver and a left side of a male cadaver, where the highest root of the greater splanchnic nerve originated from T3, in all other cases the highest root of the greater splanchnic nerve originated from T4 ganglion onwards. The greater splanchnic nerve was formed by two or more roots. A maximum number of seven roots was found in three sides of adult female cadavers (3.4%). In a large number of instances (54 cases - 64.28%) the lesser splanchnic nerve was formed by a single root. Awareness and appreciation of the variant patterns of the splanchnic nerves is of great importance to the surgeon undertaking thoracic splanchnicectomy, since this technique has been demonstrated to be of tremendous potential in pain abolition or control because of its simplicity and absence of any morbidity and potential mortality associated with thoracotomy.