SALIVARY-GLAND TRANSPLANTATION - A CANINE MODEL

Impaired salivary function with resultant severe dryness of the mouth, or xerostomia, may occur in association with a variety of systemic di sorders or therapies. No adequate treatment exists for this debilitati ng condition, which impedes normal oral function, in particular alimen tation and phonation. This study explores the feasibility of salivary gland autotransplantation, using a canine model. A salivary gland with its duct and surrounding blood vessels still attached was excised and reimplanted in the dog's thigh by anastomosing the graft's blood vess els to the femoral artery and vein. The duct was sutured to an artific ial orifice cut in the thigh's skin, from which the saliva was collect ed. Salivary secretion was induced by a single intravenous bolus of pi locarpine (5 mg). Preoperative (normal) salivation was measured by col lecting saliva from the gland in situ. Periodic functional studies sho wed normal saliva production during the first month after grafting, af ter which the salivary flow was reduced by 35% over the next 2 months. This reduction was interpreted as a sign of disuse atrophy resulting from the lack of autonomic innervation. To overcome this impediment, o ral pilocarpine (5 mg/day) was administered to the recipient dog, afte r which normal levels of saliva were excreted through the graft during the 3-month follow-up period. The quality of the graft saliva was ass essed by its protein and electrolyte levels, which showed close to nor mal values.