Transsphenoidal Pituitary Surgery

Transsphenoidal surgery reaches the pituitary through the nasal passages and sphenoid sinus rather than through a craniotomy. The target is the sella turcica, but the operation occurs beside structures that determine postoperative priorities: the optic apparatus, cavernous sinuses, pituitary stalk, hypothalamus, and posterior pituitary. The posterior pituitary does not make arginine vasopressin (AVP). It stores and releases AVP made in the hypothalamus. Surgical manipulation, oedema, stalk traction, or reduced blood supply can interrupt that release. The result may be abrupt loss of renal water conservation and a large output of very dilute urine. The first postoperative assessment is not limited to the nasal dressing. Establish a neurologic and visual baseline, assess level of consciousness, record strict intake and output, ask about thirst, obtain daily weight, and review electrolytes. A patient who becomes difficult to rouse, develops a new visual deficit, or has a sudden severe headache may have a compressive surgical complication rather than a primary endocrine disturbance. Water and electrolyte risk rises with extended endoscopic endonasal procedures because they expose more of the stalk and hypothalamic region than a...