Intramuscular injection of parathyroid autografts is a viable option after total parathyroidectomy

Surgical transplantation of parathyroid gland into muscle is an established technique after total parathyroidectomy for renal hyperparathyroidism. However, no study has examined the role of injecting parathyroid tissue in these patients. We compared the outcome of surgical transplantation of parathyroid glands by implantation ("implant") versus that of intramuscular injection ("inject").

Patients who had total parathyroidectomy for tertiary hyperparathyroidism due to chronic renal failure from 2001-2008 are included in this study. For the implant group, a parathyroid gland is divided into 10-12 pieces (each of 2-mm in diameter) before embedding into the deltoid or brachioradialis muscle. Patients in the inject group, each had a finely minced gland injected into the deltoid. Postoperatively, the graft is deemed to be functioning if 1) serum PTH is normal, or 2) serum calcium is normal in the absence of calcium supplements or reduced dosage requirements; these assays are performed at least 1 month after initial surgery. Recurrence is defined by the presence of hyperparathyroidism requiring autograft excision.

A total of 66 patients (23 men, 43 women) were included in the study. The implant group comprised 31 patients (mean age 49.9 +/- 14.0), and the inject group had 35 patients (mean age 49.2 +/- 10.4; P = 0.80). The mean follow-up period for implant was longer at 40.1 months compared with 16.2 months for inject (P = 0.001). Operative time for implant was slightly longer at 111 min versus 106 min for inject (P = 0.51). Graft function was achieved in 27 (87.1%) implant patients and 20 (69%) inject patients (P = 0.08). Recurrence was seen in four (12.9%) implant patients compared with one (2.9%) inject patient, after a mean period of 28.8 months. This difference was not statistically significant (P = 0.18).

Intramuscular injection of parathyroid tissue is a feasible alternative to surgical transplantation by implantation after total parathyroidectomy in tertiary hyperparathyroidism. The injection method was slightly faster to perform. However, injection achieved a slightly lower graft function rate but the risk of autograft hyperplasia also was lower.