Parathyroid Subcutaneous Pre-sternal Transplantation after Parathyroidectomy for Renal Hyperparathyroidism. Long-term Graft Function

Factors influencing the success of cryopreserved parathyroid autotransplantation: A systematic review

Permanent hypoparathyroidism is a postoperative complication of thyroid and parathyroid surgery and can be cured by cryopreserved parathyroid autotransplantation (CPAT). However, due to the lack of unified and standardized guidelines, the limited ability of the parathyroid tissue itself to withstand cryopreservation, and some yet-to-be-defined processes or technologies, the success rate of cryopreserved parathyroid autotransplantation varies between institutions; it is low for some institutions and high for others. Due to the sparsity of data, views vary on which factors most influence the success rate of cryopreserved parathyroid autotransplantation. In this review, we analyzed the following probable influencing factors: ischemic period before cryopreservation; processes of cryopreservation and thawing, including freezing medium; freezing and thawing methods; duration of cryopreservation; examination of the graft before transplantation; graft site; mass of transplanted tissue fragments; blood calcium level; and the evaluation criteria for cryopreserved parathyroid autotransplantation success. Although the effects of these factors are debatable, we hypothesized that examining them in the above-given order to determine whether they affect the success rate of cryopreserved parathyroid autotransplantation could be beneficial to maximizing the success rate. Our findings led us to conclude that cryopreserved parathyroid autotransplantation operations should be standardized. Standardized guidelines for cryopreserved parathyroid autotransplantation that include such factors as ischemic period time, freezing and thawing methods, and recipient status should be established based on a comprehensive analysis of these factors.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Secondary and Tertiary Renal Hyperparathyroidism

OBJECTIVE

To develop evidence-based recommendations for safe, effective, and appropriate treatment of secondary (SHPT) and tertiary (THPT) renal hyperparathyroidism.

BACKGROUND

Hyperparathyroidism is common among patients with chronic kidney disease, end-stage kidney disease, and kidney transplant. The surgical management of SHPT and THPT is nuanced and requires a multidisciplinary approach. There are currently no clinical practice guidelines that address the surgical treatment of SHPT and THPT.

METHODS

Medical literature was reviewed from January 1, 1985 to present January 1, 2021 by a panel of 10 experts in SHPT and THPT. Recommendations using the best available evidence was constructed. The American College of Physicians grading system was used to determine levels of evidence. Recommendations were discussed to consensus. The American Association of Endocrine Surgeons membership reviewed and commented on preliminary drafts of the content.

RESULTS

These clinical guidelines present the epidemiology and pathophysiology of SHPT and THPT and provide recommendations for work-up and management of SHPT and THPT for all involved clinicians. It outlines the preoperative, intraoperative, and postoperative management of SHPT and THPT, as well as related definitions, operative techniques, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Preoperative and Perioperative Care, Surgical Planning and Parathyroidectomy, Adjuncts and Approaches, Outcomes, and Reoperation.

CONCLUSIONS

Evidence-based guidelines were created to assist clinicians in the optimal management of secondary and tertiary renal hyperparathyroidism.

[Risk factors affecting graft survival after parathyroidectomy and parathyroid autotransplantation in patients on maintenance hemodialysis]

OBJECTIVE

To investigate the risk factors affecting the survival of parathyroid autograft following total parathyroidectomy combined with autologous sternocleidomastoid muscle transplantation (TPTX + AT) in patients on maintenance hemodialysis (MHD) complicated with secondary hyperparathyroidism (SHPT).

OBJECTIVE

This retrospective study was conducted among the patients on maintenance hemodialysis with SHPT, who underwent successful parathyroidectomy and autotransplantation from January, 2010 to February, 2020 in our hospital. The clinical data and serum levels of calcium, phosphorus, intact parathyroid hormone, hemoglobin, and alkaline phosphatase (ALP) of the patients were collected. The enrolled patients were divided into survival group with bilateral forearm parathyroid hormone (iPTH) ratio > 1.5 and death group with a ratio < 1.5 at 2 weeks after surgery for comparison of the clinical data and perioperative indicators. The risk factors of postoperative parathyroid autograft survival were analyzed using logistic regression analysis.

OBJECTIVE

A total of 87 patients were included in the study, among whom the graft survival rate after parathyroid transplantation was 78.16%. In both groups, serum levels of calcium, phosphorus, iPTH and ALP decreased and hemoglobin level increased significantly at 1 week and 1, 2, 3, 6 and 12 months after surgery (P < 0.01). Logistic regression analysis showed that serum ALP level was an independent risk factor for graft survival following parathyroid autotransplantation [OR=1.003, 95% CI: 1.001-1.005, P=0.004].

OBJECTIVE

TPTX+AT is a safe and effective treatment for SHPT, and parathyroid autografts are less likely to survive following parathyroid transplantation in patients with high preoperative level of ALP.

Total Parathyroidectomy with Subcutaneous Parathyroid Forearm Autotransplantation in the Treatment of Secondary Hyperparathyroidism: A Single-Center Experience

INTRODUCTION

Secondary hyperparathyroidism is common in chronic kidney disease. Parathyroidectomy is indicated in refractory hyperparathyroidism when medical treatments and so the parathyroid hormone levels cannot be lowered to acceptable values without causing significant hyperphosphatemia or hypercalcemia. The aim of this study is to compare the efficacy and safety of total parathyroidectomy with subcutaneous forearm autotransplantation with total parathyroidectomy with intramuscular forearm autotransplantation.

MATERIALS AND METHODS

A single-center retrospective cohort study of total parathyroidectomy with forearm autotransplantation from January 2002 to February 2013 was performed. According to the surgical technique, patients were divided into an intramuscular group (Group 1) and a subcutaneous group (Group 2). 38 patients with secondary hyperparathyroidism were enrolled; 23 patients were subjected to total parathyroidectomy with parathyroid tissue replanting in the subcutaneous forearm of the upper nondominant limb, while 15 patients were subjected to replanting in the intramuscular seat.

RESULTS

A total of 38 patients (56 ± 13 years) were enrolled. In both groups, the preoperative iPTH value was markedly high, 1750 ± 619 pg/ml in the intramuscular autotransplantation group and 1527 ± 451 pg/ml in the subcutaneous autotransplantation group (p = 0.079). Transient hypoparathyroidism was shown in 7 patients, and 1 patient showed persistent hypoparathyroidism (p = 0.387). 2 patients showed persistent hyperparathyroidism (p = 0.816), and in 2 others was found recurrent hyperparathyroidism (p = 0.816); 3 of them underwent autograftectomy. The anterior compartment of the forearm nondominant limb was sacrificed in 1 case of intramuscular autotransplantation with functional arm deficit.

CONCLUSIONS

The efficacy and safety of parathyroid tissue autotransplantation in the subcutaneous forearm of the upper nondominant limb is confirmed with a good rate of tissue engraftment and with a comparable number of postsurgical transient and persistent hypoparathyroidism and hyperparathyroidism incidence in both techniques. Furthermore, this technique preserves arm functionality in the case of autograftectomy. Consequently, it is our opinion that total parathyroidectomy with subcutaneous forearm autotransplantation is currently the best choice.

PTH monitoring after total parathyroidectomy with forearm auto-transplantation: potential for spuriously high levels from grafted forearm

Background

We have identified a cause of falsely elevated parathyroid hormone (PTH) levels after total parathyroidectomy with forearm auto-transplantation (TPT-ATx). Our cases highlight the need to draw PTH samples remotely, away from forearm graft sites, to ensure accurate levels.

Case presentations

We report on four patients who were referred to our surgical team at an academic tertiary care center for what was perceived to be recurrent hyperparathyroidism 2–5 years following total parathyroidectomy with auto-transplantation. Further evaluation revealed highly discrepant results in these patients depending on where the blood was drawn, with spuriously high levels in blood drawn from the grafted arm (Range 337–3885 ng/l), and much lower levels when blood was drawn remotely away from the graft site (Range 9–242 ng/l). The difference in PTH level between the grafted forearm and remote site for these patients ranged between 328 and 3643 ng/l.

Over the period these cases were accrued (2008–2012), 89 patients underwent TPT-ATx in our institution. Therefore, our case report series suggests that this phenomenon will be evident to a clinically important extent in at least 4% of patients.

Conclusions

One can acquire spuriously high PTH levels from grafted forearms, leading to the false diagnosis of recurrent hyperparathyroidism. We recommend PTH levels be drawn remotely from graft sites to ensure accurate systemic levels are reflected.

Parathyroid Autotransplantation During Thyroid Surgery: A Novel Technique Using a Cell Culture Nutrient Solution

INTRODUCTION

Parathyroid autotransplantation is an easy procedure with a low complication rate. We adopted the transplantation into the sternocleidomastoid muscle, which allows an easier and time-saving surgical procedure using the same surgical incision.

METHODS

In this study, we retrospectively reviewed the records of 396 consecutive patients, who underwent total thyroidectomy for benign thyroid disease. In all cases in which a parathyroid was damaged or inadvertently removed, the gland was transplanted; before the autotransplantation, the parathyroid tissue was put in a cell culture nutrient solution for 5 min, afterward fragmented, and then was transplanted in the sternocleidomastoid muscle. To demonstrate a beneficial effect of the cell nutrient solution step, we compared data of transplanted patients with a control group of cases (n = 190) undergoing a standard immediate autotransplantation.

RESULTS

We divided patients in two main groups: group A (n = 160) including subjects that underwent one or more parathyroid gland autotransplantation using the cell nutrient solution, and group B (n = 236) concerning those who were not transplanted. Among patients, 62 hypocalcemias occurred, 40 in the group A and 22 in the group B (P < 0.001): 91.9 % were transient and 8.1 % (5 patients) definitive, all pertaining to the group B. Among controls (group C), 42 hypocalcemias occurred (P = 0.616 vs. group A and P = 0.002 vs. group B) and 3/42 became definitive (P = 0.096 vs. group A and P = 0.121 vs. group B). All differences concerning pre- and postoperative calcium values were statistically significant (P < 0.001).

CONCLUSIONS

We recommend the routine parathyroid autotransplantation, when a vascular damage is certain or suspected, in order to reduce the rate of permanent hypoparathyroidism, using a cell culture nutrient solution before gland transplantation.

Feasibility of injectable thermoreversible gels for use in intramuscular injection of parathyroid autotransplantation

Surgical transplantation of parathyroid tissue into the forearm muscle is one of the most commonly used surgical techniques. While simple, the procedure suffers from drawbacks. This study evaluated the feasibility of thermoreversible gel as an injectable carrier for parathyroid autotransplantation. Polyethyleneglycol-polyalanine-co-phenylalanine (PEG-PAF) thermoreversible gel (sol form at 4 °C, gel form at 37 °C) were manufactured. Thirty-eight Sprague-Dawley rats were divided into two groups (19 control, C group; 19 experimental, P group). The parathyroid glands of rats were excised. Parathyroid tissues were transplanted into the muscle pocket in sternocleidomastoid muscle in the C group. In the P group, the tissues were injected into the same muscle mixed with 0.3 ml thermoreversible gel. The serum levels of parathyroid hormone (PTH), ionized calcium, and phosphorous were measured before surgical procedure, on 7, 21, 56, and 70 days after surgery. Histology and immunohistochemistry were performed. Preoperative median PTH level of the C and the P group were 60.80 and 43.85 pg/ml, respectively (p = 0.641). Seventy days after surgery, median PTH level was 32.8 and 25.61 pg/ml, respectively. On day 70, the PTH level was restored by 54 % in the C group and 56 % in the P group compared to the preoperative value (p = 0.620). There were no significant intergroup differences in the ionized calcium/phosphorous level. Histology and immunohistochemistry revealed the successful transplantation of parathyroid tissues into the muscles in both groups. In conclusion, the PEG-PAF-based thermoreversible gel is a good candidate carrier material for intramuscular parathyroid autotransplantation.

Autotransplantation of parathyroid grafts into the tibialis anterior muscle after parathyroidectomy: a novel autotransplantation site

Background

Surgical management of renal secondary hyperparathyroidism (sHPT) is varying. Total parathyroidectomy with heterotopic autotransplantation (TPTX + AT) is one of the standard surgical procedures in sHPT, but there is no consensus about the optimal site for graft insertion. At the surgical department of the University Hospital of Heidelberg we prefer the autotransplantation into the tibialis anterior muscle. The aim of this study was to assess the long-term function of the auto-transplanted parathyroid tissue in this type of surgical procedure.

Methods

The function of the autograft of 42 patients was assessed 8.2 ± 2.5 years after surgery, using a modified Casanova-test of the leg bearing the parathyroid tissue. Ischemic blockage was induced by tourniquet and the levels of parathyroid hormone (PTH) were assessed during the test.

Results

At the point of assessment, the ischemic blockage led to a significant reduction in the concentration of PTH (≥50 % of the baseline value) in 19 patients (45 %) indicating well-functioning autografts. In 11 patients (26 %), ischemic blockage did not cause any change in the concentration of PTH (≤20 % of the baseline value), indicating functioning residual parathyroid tissue from another site. The source of PTH production was classified as unidentifiable in five patients (12 %). Two patients had developed graft-dependent recurrent HPT (5 %) without therapeutic consequences and three patients suffered from persistent symptomatic hypoparathyroidism (7 %).

Conclusions

These results indicate that TPTX + AT into the tibialis anterior muscle is a successful surgical treatment for renal HPT and that the modified Casanova-test is a suitable diagnostic tool for autografts function.

Long-term function of parathyroid subcutaneous autoimplantation after presumed total parathyroidectomy in the treatment of secondary hyperparathyroidism. A clinical retrospective study

INTRODUCTION

Parathyroidectomy (PTx) is recommended in patients affected by secondary hyperparathyroidism (2HPT) of chronic kidney disease-mineral bone disorders (CKD-MBD), resistant to medical treatment. Analyzing total parathyroidectomy with muscular or subcutaneous autoimplantation (TPai) outcomes in hemodialysis (HD) 2HPT patients, and monitoring intact parathyroid hormone (iPTH) levels, we evaluated long-term functional results of subcutaneous parathyroid glandular tissue autoimplantation.

METHODS

40 HD 2HPT patients, resistant to medical treatment, and awaiting for renal transplantation, underwent total parathyroidectomy with subcutaneous autoimplantation of 9-12 fragments of not nodular hyperplasia parathyroid tissue in not dominant forearm. iPTH were analyzed 24 h, and 3-6-12-24 months after surgery. The 1.08-6.99 pmol/L range was taken as reference of normal iPTH level based on which eu- (1.08-6.99), hypo- (<1.08), aparathyroidism (0) and persistence or relapse (>6.99) of disease were determined.

RESULTS

In every case PTai determined an extraordinary improvement of quality of life, associated with a notable reduction of iPTH serum level. Immediate normalization of iPTH was achieved in 50% of cases; hypoparathyroidism in 25% of cases and persistence of disease in 25% were observed. Long term follow-up showed a reduction of hypoparathyroidism and an increase of relapse rate up to 20%. Grafting resection was never performed.

DISCUSSION

Subcutaneous autotrasplantation is a very simple and fast surgical technique. Nevertheless, similar success and recurrence rates were reported following muscular or subcutaneous grafting, as confirmed in our experience.

CONCLUSIONS

Subcutaneous grafting was effective as muscular implantation, with comparable functional results, but avoiding its potential complications.

Results of cryopreserved parathyroid autografts: a retrospective multicenter study

BACKGROUND

The functionality of cryopreserved parathyroid autotransplantation (CPAT) has been evaluated in few studies, mostly conducted by experienced single-institution centers that have reported different success rates ranging from 17% to 83%. In France, CPAT are rare and their functionality has never been evaluated. Moreover, French tissue banks are facing an accumulation of ungrafted samples. The aim of our work was to evaluate the implantation rate of cryopreserved parathyroid samples and the functionality of CPAT in a multicenter study.

METHODS

Data from 9 French tissue banks were analyzed. CPAT functionality was defined as fully functional (normal parathyroid hormone [PTH] and calcium levels without treatment), partially functional (normal PTH levels but need for treatment to maintain normocalcemia), and nonfunctional (low PTH levels and need for treatment). For dialyzed patients, CPAT was considered nonfunctional if the PTH level in the nongrafted arm was less than 20 pg/mL, partially functional if the PTH level was between 20 and 50 pg/mL, and fully functional if the PTH level was between 50 and 300 pg/mL.

RESULTS

The 9 centers had cryopreserved 1376 samples of parathyroid tissue and only 22 (1.6%) had been autografted in 20 patients (65% renal hyperparathyroidism, 20% multiple endocrine neoplasia type 1, 15% "other") by 12 different surgical teams. The median duration of storage was 11.1 months (range, 0.4-28.5). Only 2 autografts (10%) were fully functional, 2 (10%) were partially functional, and 17 (80%) were nonfunctional at 26 months median follow-up.

CONCLUSION

The reimplantation rate is low, and the functionality of CPAT is less than those published by experienced centers. Logistical and technical problems occurring in less experienced centers are probably the main reasons for nonfunctioning implants. Considering the results of this study, we suggest that cryopreservation of parathyroid glands should be abandoned when not performed in very large experimented centers, that CPAT should be used only for patients with hyperplasic parathyroid tissue, and that tissue samples should be systematically destroyed when patients do not have hypoparathyroidism or after 1 year of storage.

Quality monitoring of microbial contamination of cryopreserved parathyroid tissue

Cryopreservation of parathyroid tissue (PT) provides patients undergoing parathyroidectomy with an option for delayed autologous heterotopic parathyroid transplantation. A standard protocol for quality monitoring of PT has not been established. This article describes a method for detecting the presence of bacterial contamination in PT tissue intended for autologous transplantation. PT was received in the tissue bank, processed under aseptic conditions, and placed into cryopreservation medium. Sterility testing was performed at 2 time points prior to cryopreservation. From January 2005 to October 2008, 47 PT samples were cryopreserved. The following bacteria were isolated from 11 PT specimens: Staphylococcus epidermidis, Staphylococcus capitis subspecies ureolyticus, Staphylococcus lugdunensis, Bacillus pumilus, and corynebacteria (diphtheroids). 23% of PTs were contaminated at the time of collection, predominantly with indigenous bacteria. Quality monitoring using this protocol is a useful tool to identify tissues contaminated with bacteria.