Parathyroid subcutaneous pre-sternal transplantation after parathyroidectomy for renal hyperparathyroidism. Long-term graft function.

BACKGROUND

In the setting of total parathyroidectomy (TPT) and parathyroid transplantation (PTx) for renal hyperparathyroidism (RHP), we evaluated long-term parathyroid graft function after subcutaneous pre-sternal transplantation (SCPTx). Because parathyroid glands are surrounded by fatty tissue, we postulated that results of subcutaneous implantation of parathyroid tissue after total parathyroidectomy for renal hyperparathyroidism could be at least as successful as intramuscular grafting, but without its complications.

PATIENTS AND METHODS

The study, a prospective open efficacy study of postoperative (po) diagnostic monitoring of intact parathyroid hormone (iPTH) on a cohort of surgical patients, was conducted within a university hospital with a dialysis unit. Thirty five patients (19 women and 16 men) operated on for renal hyperparathyroidism underwent TPT and SCPTx for RHP at the Department of General Surgery and the Department of Nephrology. Donostia Hospital. San Sebastián. Gipuzkoa. Spain, from January 2002 to December 2005. Follow-up ranges from 6 months to 42 months (median: 15.4 months). The main outcome measure was evaluation of graft function by measurement of iPTH plasma level, based on serum levels of iPTH before operation and 24 h and 1, 3, 5, 15, 30, 60, 100, and 150 weeks after surgery.

RESULTS

Average preoperative iPTH values were 1,341.52 + 367.78 pg/ml (mean +/- SD) (range: 493-2,180). After TPT and PSCTx, iPTH levels became undetectable in all patients at 24 h. A level of 50 pg/ml was established as the criterion of adequate parathyroid graft function. Values obtained at the various time intervals were as follows: 14.14 + 7.73 1 pg/ml (mean +/- SD) (range: 6-36) after 1 week, 53 + 77.33 pg/ml (mean +/- SD) (range: 35-74) after 5 weeks, 62.95 + 20.93 pg/ml (mean +/- SD) (range: 11-89) after 15 weeks, 77.54 + 18.84 pg/ml (mean +/- SD) (range: 24.6-104.2) after 30 weeks, 109.29 + 50.22 pg/ml (mean +/- SD) (range: 54-327) after 60 weeks, 134.21 + 128.64 pg/ml (mean +/- SD) (range: 43-712) after 100 weeks, and 122.84 + 117.54 pg/ml (mean +/- SD) (range: 68-723) after 150 weeks. Prevalence of hypoparathyroidism (intact parathyroid hormone serum level < 20 pg/ml with a normal or low serum calcium concentration) was 2/35 (5.71%) by week 60 and recovered by week 100. Graft-related recurrence was 2.85% (1/35).

CONCLUSIONS

Subcutaneous pre-sternal transplantation (SCPTx) after TPT and PTx for secondary (RHP) is an adequate method to replace muscular forearm parathyroid transplantation and avoid its complications. Functioning 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. Results of long-term follow-up exceed previously reported results.