The syndrome of inappropriate antidiuretic hormone secretion after bilateral radical neck dissections

It is commonly believed that synchronous, bilateral radical neck dissection causes the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), presumably as a result of increased intracranial pressure. This belief is based mainly on the results of an experimental study published in 1978 in which occlusion of the superior vena cava in dogs resulted in increased intracranial pressure and SIADH. The purpose of the present study was to test this assumption in an animal model that more closely resembles the clinical condition of bilateral radical neck dissection, in an attempt to discover possible surgical methods for preventing SIADH.

The experiments were carried out in six adult mongrel dogs. In two animals the internal and external jugular veins were ligated on both sides of the neck, high in the neck and at the thoracic inlet, respectively. In four animals, a formal radical neck dissection was performed on both sides of the neck. Urine and serum osmolarity and serum electrolyte levels were measured prior to surgery and at 2.5, 24, 48 and 120 h after surgery, in order to monitor the development of SIADH.

No significant changes in serum osmolarity, urine osmolarity or serum sodium levels were observed in any of the animals studied.

Bilateral synchronous jugular vein ligation and bilateral radical neck dissections did not result in SIADH in a dog model. As these results contradict a commonly held belief in clinical practice, a prospective evaluation of the physiologic changes after bilateral radical neck dissections is warranted.