Recurrence of hyperparathyroidism after total parathyroidectomy with autotransplantation: a new technique to localize the source of hormone excess

Removal of autografted parathyroid tissue for recurrent renal hyperparathyroidism in hemodialysis patients

BACKGROUND

Recurrent renal hyperparathyroidism (HPT) is a serious problem after parathyroidectomy (PTx). We evaluated the frequency of graft-dependent recurrent HPT and the clinical outcomes after removal of the autograft.

METHODS

Between March 1980 and January 2009, 2660 patients underwent total PTx with forearm autograft. After resection of all parathyroid glands, 30 pieces of 1 x 1 x 3 mm parathyroid tissue from diffuse hyperplasia, if possible, were autografted into brachioradial muscle. Graft-dependent recurrence of HPT was diagnosed by a high PTH gradient and detection of swollen autografts by palpation and/or MRI or US.

RESULTS

In 248/2660 (9.3%) patients, removal of the graft was required a total of 327 times (53 patients required removal of the autograft several times). The cumulative frequency of graft-dependent recurrent HPT was 17.4% ten years after the initial PTx. Thirty-two patients underwent both resection of missed glands located in the neck or mediastinum and removal of the graft. En-bloc resection of autograft with surrounding muscle was required to avoid reoperation. When the intact PTH level dropped under 300 pg/ml, in the majority of patients renal HPT could be medically managed after the operation. The mean weight of the resected parathyroid tissue was 1583.7 mg. No specimen had histopathologically malignant features. Three patients suffered from hematoma in the wound.

CONCLUSIONS

Graft-dependent recurrent renal HPT is not negligible. However, in the majority of patients, renal HPT can be controlled by removal of the autograft noninvasively. Total PTx with forearm autograft is preferable for hemodialysis patients, especially when long-term survival is expected.

Surgical treatment of secondary hyperparathyroidism due to chronic kidney disease

It is a great honour for me to have this opportunity to present a review about surgical treatment of secondary hyperparathyroidism (2HPT) due to chronic kidney disease (CKD). Uppsala is a historical place concerning the parathyroid gland, because it was here that Ivar Sandström in 1877 initially discovered the small organs, Glandulae Parathyroideae, existing around the thyroid gland in human beings. This finding led to intensive studies of the parathyroid glands, focusing on their histopathology, pathophysiology, clinical diagnosis, and medical and surgical treatment (1) and investigations are still continuing in Uppsala today. I had the privilege to stay in Uppsala during 1989 to study the surgery and pathology of parathyroid glands and it was a pleasure to share clinical and basic research about these small and charming organs with my colleagues in Uppsala.

Parathyroidectomy in dialysis patients

Subtotal parathyroidectomy or total parathyroidectomy (PTx) with autotransplantation are surgical procedures considered while the patient is included on the waiting list for renal transplantation. Total PTx alone is based in the possibility that a fragment of tissue (nodular hyperplasia in particular) left in the same pathophysiological environment of long term dialysis would show the same behavior and reproduce in time the same clinicopathological picture. The persistence of uremia induces a continued growth stimulus developing residual hyperplasia and consequently a very high risk of recurrence. We performed total PTx alone in 15 uremic patients excluded for renal transplantation 10 patients with undetectable iPTH serum concentration and were followed up for 37 to 144 months. There was no evidence of clinical bone disease (bone pain or fractures). Bone mineral lumbar spine and hip density was measured at the end of follow-up. The z score data showed that all patients had a bone mass similar than that expected for their age. Bone biopsies performed in four patients showed a uniform picture of low turnover without aluminium staining. Calcification of small arteries (digital and arcade vessels in hands and feet) were evaluated pre and post total PTx alone in nine out of the 10 patients with undetectable PTH levels. The small vessel calcification was present in five patients at the moment of PTx. At the end of the long term follow-up only one patient showed progression. In conclusion, total PTx without autotransplantation is a very effective and adequate treatment for refractory severe hyperparathyroidism in patients excluded for renal transplantation. Aluminium related osteopathy post PTx is a risk to be controlled with aluminium "free" dialysis water and avoiding aluminium containing phosphate binders.

Surgical treatment of renal hyperparathyroidism

Advanced secondary (renal) hyperparathyroidism induced by chronic renal disturbance is one of the most serious complications for long-term hemodialysis patients. Parathyroidectomy is indicated in patients with severely advanced renal hyperparathyroidism refractory to medical treatment (including calcitriol pulse therapy) and the clinical effect of parathyroidectomy is striking. However, skeletal deformity, vessel calcification, and remarkable reduction of bone content is irreversible, and it is important to perform parathyroidectomy at right time. Based on histopathological and pathophysiological investigations, nodular hyperplasia is monoclonal neoplasia with abnormal parathyroid hormone (PTH) response to extracellular calcium and vitamin D. When parathyroid hyperplasia progresses to nodular hyperplasia, parathyroidectomy should be required. Total parathyroidectomy with forearm autograft is the preferable procedure for renal hyperparathyroidism, especially for patients who need to continue hemodialysis treatment after parathyroidectomy. Removal of all parathyroid glands, including supernumerary glands, at the initial operation, and proper choice of adequate parathyroid tissue for autograft, are important to prevent persistent and recurrent hyperparathyroidism. Preoperative image diagnosis is useful for localization, and routine resection of thymic tissue is necessary to remove supernumerary glands. In our series of 548 patients, graft-dependent recurrent hyperparathyroidism was not negligible and the incidence was about 20% at the 5th year postoperatively. Enlarged autografts of parathyroid tissue could be removed from forearm under local anesthesia with fewer invasions. The function of autografted parathyroid tissue is nearly satisfactory and no re-transplantation of cryopreserved parathyroid tissue was necessary. To avoid adynamic bone disease, relatively high PTH level is required-over-suppression of PTH by excess of vitamin D and calcium salts should be avoided. In our experience, total parathyroidectomy with forearm autograft is very effective and adequate treatment for advanced renal hyperparathyroidism, and parathyroid function can be controlled after parathyroidectomy.

Parathyroid function and bone metabolic markers in primary and secondary hyperparathyroidism

Remarkable changes of parathyroid function immediately after parathyroidectomy were evaluated in primary (PHPT) and secondary (RHPT) hyperparathyroidism. Bone metabolism was also evaluated by new specific markers of bone formation and resorption. A rapid decline into the undetectable range, and a rapid recovery of serum bioactive parathyroid hormone (PTH) concentrations were observed after parathyroidectomy in PHPT. Since the function of the remnant parathyroid glands was not clear, we investigated the transcription of PTH mRNA. Despite the suppression of PTH secretion in the remnant parathyroid glands, no significant difference was found in the amount of PTH mRNA present in an adenoma as compared to a remnant gland when evaluated by cytoplasmic dot hybridization and in situ hybridization. Although measurement of serum PTH concentration by assays of inactive fragment was available for the longterm follow-up of PTH function in RHPT, parathyroid function should be evaluated by biologically active intact PTH immediately after operation. The PTH gradient also was successfully evaluated by the measurement of intact PTH. A discrepancy was observed between bone resorption evaluated by type I collagen cross-linked N-telopeptide as compared to bone formation evaluated by osteocalcin immediately after operation. This discrepancy will improve and bone mineral density will increase in the first 6 months after parathyroidectomy.

Primary hyperparathyroidism: problems in management

Most hyperparathyroidism is subclinical, with no complaints of bone pain, constipation, mental confusion, or depression, no skeletal findings on x-ray, and no history of kidney stones. Routine hyperparathyroidectomy for asymptomatic hypercalcemia, with normal bone density and normal calciuria, particularly with moderate elevations of serum calcium, is now generally rejected.