Long-term results of subcutaneous parathyroid grafts in uremic patients.

HYPOTHESIS: Parathyroid glands are normally surrounded (entirely or partially) by fatty tissue. Subcutaneous parathyroid grafts are thus located in a normal environment. Therefore, we postulated that the late results of subcutaneous implantation of parathyroid tissue in uremic patients should be at least as good as those reported for intramuscular grafting. We also challenged the idea that the recurrence rate of renal hyperparathyroidism after surgery depended solely on the type of hyperplasia (diffuse vs nodular) observed in the implanted tissue.
DESIGN: A retrospective study of a series of patients without loss to follow-up.
SETTING: A university hospital and 9 affiliated dialysis units. PATIENTS AND
INTERVENTIONS: Fifty-nine patients (33 women and 26 men) operated on for renal hyperparathyroidism underwent the resection of at least 4 parathyroid glands followed by presternal subcutaneous implantation of parathyroid tissue. They were followed up for 12 to 130 months (median, 38 months). MAIN OUTCOME MEASURES: Failure of treatment, recurrence of disease, and hypoparathyroidism.
RESULTS: During the study period, 9 patients had to undergo another operation: 2 (3%) for persistent hyperparathyroidism due to a fifth ectopic gland and 7 (12%) for recurrence of hyperparathyroidism resulting from hypertrophy of the subcutaneous grafts. Four patients received a kidney transplant. The prevalence of hypoparathyroidism (intact parathyroid hormone serum level <1.6 pmol/L with a normal or low serum calcium concentration) was 14% (8 of 59 patients), and the curve representing the distribution of intact parathyroid hormone serum concentrations among operated on patients was shifted to the left when compared with the curve of patients who underwent hemodialysis and who had no indication for parathyroid surgery. In this latter group, the peak of the curve was situated between 1 and 2 times the upper normal limit, while it was in the normal range 12 to 130 months after total parathyroidectomy and subcutaneous parathyroid autotransplantation. No relation was observed between the recurrence rate of the disease and the histological characteristics of the parathyroid grafts. Also, their function was not influenced by the presence or absence of aluminum deposits in bone biopsy specimens that were obtained at the time of cervical exploration.
CONCLUSIONS: The late results of total parathyroidectomy and presternal subcutaneous grafting compare favorably with the published data on other surgical techniques proposed for the treatment of renal hyperparathyroidism. The ease with which the hypertrophied grafts are removed when the disease recurs warrants further use of this procedure.