Total parathyroidectomy and autotransplantation by the subcutaneous injection technique in secondary hyperparathyroidism

PURPOSE

To prospectively assess the effectiveness of total parathyroidectomy and autotransplantation using a subcutaneous injection technique to treat secondary hyperparathyroidism.

METHODS

We used this method to treat 14 patients with secondary hyperparathyroidism. The short-term outcome, up to 16 months after surgery, was monitored by measuring calcium, inorganic phosphorus, intact parathyroid hormone (iPTH), and alkaline phosphatase levels. We considered a graft viable when the ratio of iPHT in antecubital venous blood from the grafted arm to that from the nongrafted arm exceeded 1.5.

RESULTS

Autografted parathyroid tissue was functional in 12 (85.7%) patients. An iPTH ratio > or =1.5 in the grafted arm relative to the nongrafted arm was observed from 2 weeks after surgery, peaking at 1 month. The grafted tissue continued to be biochemically functional 16 months after surgery in 12 patients.

CONCLUSION

These findings suggest that total parathyroidectomy and forearm autotransplantation using the subcutaneous injection technique is a possible alternative to Wells' method for surgical treatment of secondary hyperparathyroidism.

Total parathyroidectomy with autotransplantation in patients with renal hyperparathyroidism: indications and surgical approach

OBJECTIVE

renal hyperparathyroidism (rH) is one of the most serious complications in long-term hemodialysis patients. the purpose of this retrospective study was the evaluation of the surgical indications, parathyroid histology, and the results of total parathyroidectomy with autotransplantation (Ptx+At) in patients with rH.

DESIGN

the study included 36 patients with rH in whom Ptx+At was carried out at the First surgical Department of the Evangelismos Hospital over a 5-year period. Indications for Ptx+At were high levels of parathyroid hormone (PtH >800 ng/L) associated with hypercalcemia and/or hyperphosphatemia, that were refractory to medical treatment, as well as clinical effects of rH, including pruritus, bone and joints pain, muscle weakness, progression of soft tissue calcification, and spontaneous fractures. Ultrasonography, (99m)Tc sestamibi scan and computed tomography were used to evaluate the thyroid and parathyroids.

RESULTS

there was no mortality related to surgery. Preoperative symptoms, serum PtH, serum alkaline phosphatace, hyperphosphatemia, and hypercalcemia were improved or normalised in most patients. recurrence was observed in one case; this autotransplanted patient required resection of transplanted tissue from his forearm. Hypoparathyroidism was not recorded.

CONCLUSIONS

Ptx+At is a safe option for the treatment of rH that is accompanied by low morbidity, mortality, and recurrence rate. It is important to identify all parathyroid glands at surgery and to choose adequate parathyroid tissue for autograft.

Rapid recurrence of hyperparathyroidism from both nodularly hyperplastic autograft at forearm and residual tissues at neck after parathyroidectomy in a hemodialysis patient with calciphylaxis

A 42-year-old woman underwent hemodialysis secondary to diabetic nephropathy. Total parathyroidectomy with forearm autograft was performed due to secondary hyperparathyroidism (HPT) complicated with calciphylaxis. Rapidly progressive enlargement of autograft with unusual "gourd-shape" developed, and then it was removed. Pathologic examination of the autograft disclosed multinodular hyperplasia. Residual parathyroid gland in the retrothyroid region was found later. Rapidly recurrent HPT originating from both the residual parathyroid tissues and the enlarged autograft within such short time after parathyroidectomy is rare in the literature. The multinodular hyperplasia pattern of the parathyroid gland may be a major factor for such rapid recurrence. In addition to good control of calcium and phosphate, regular follow-up of parathyroid hormone level and imaging studies of not only autografted gland at the forearm but also possibly residual parathyroid tissues at the neck are important for monitoring recurrence in maintenance hemodialysis patients after parathyroidectomy with forearm autograft, especially in those with pathologic type of nodular hyperplasia and calciphylaxis.

Subtotal parathyroidectomy as an adequate treatment for primary hyperparathyroidism in multiple endocrine neoplasia type 1

HYPOTHESIS

The most appropriate surgical approach for hyperparathyroidism (HPT) in multiple endocrine neoplasia type 1 remains controversial. It has been advocated that reoperations for recurrent disease are easier to perform after total parathyroidectomy (TP) with autotransplantation than after subtotal parathyroidectomy (SP). In view of our large experience in patients with secondary HPT for whom TP with autotransplantation did not simplify reoperations, SP remains our preferred treatment for patients with HPT and multiple endocrine neoplasia type 1.

DESIGN

Retrospective cohort study.

SETTING

Tertiary referral medical center.

PATIENTS

A total of 29 consecutive patients (22 women, 7 men; mean age, 42.2 years) with multiple endocrine neoplasia type 1 who underwent definitive cervical exploration for HPT.

MAIN OUTCOME MEASURES

Temporary and permanent hypocalcemia, pattern of parathyroid disease, and sites and timing of recurrent HPT. Definitive primary surgery included SP in 21 patients, TP with autotransplantation in 4 patients, and less-than-subtotal parathyroidectomy in 4 selected patients.

RESULTS

The mean follow-up was 88.5 months (range, 8-285 months). Four patients died during follow-up; 2 of these deaths were related to multiple endocrine neoplasia. No patients had persistent HPT. Temporary hypocalcemia occurred in 12 SP cases (57%), 4 TP with autotransplantation cases (100%), and 0 less-than-subtotal parathyroidectomy cases. Permanent hypocalcemia requiring long-term treatment occurred in 2 SP cases (10%), 1 TP with autotransplantation case (25%), and 0 less-than-subtotal parathyroidectomy cases. Four patients developed recurrent disease, including 1 with SP, 2 with TP with autotransplantation, and 1 with less-than-subtotal parathyroidectomy at 57 months, 197 and 180 months, and 164 months, respectively, representing 14% of all of the patients and 43% of patients with more than 10 years of follow-up.

CONCLUSIONS

Recurrent HPT occurs many years after definitive primary surgery (median, 14.3 years). Surgical treatment should therefore aim to minimize the risk of permanent hypocalcemia and facilitate future surgery. When correctly performed, SP fulfills these objectives.

Long-term functionality of cryopreserved parathyroid autografts: a 13-year prospective analysis

BACKGROUND

The functional results of cryopreserved heterotopic parathyroid autotransplantation (CHPA) are not well defined. The authors evaluated the outcomes of delayed CHPA for the treatment of surgically induced hypoparathyroidism.

METHODS

Since November 1991, 448 parathyroid samples from 436 patients were cryopreserved at our institution. Of these, 29 patients underwent 34 CHPA procedures, with placement of 20 to 25 pieces of parathyroid tissue (approximately 50 to 75 mg) into the forearm. Outcomes were determined based on peripheral parathyroid hormone (PTH) levels and, where available, PTH gradients between grafted and nongrafted arms. Graft function results were defined as completely functional (patients with normal PTH and calcium levels off all calcium/vitamin D supplementation), partially functional (normal PTH levels and mild hypocalcemia on calcium supplementation), or nonfunctional (low PTH levels and dependent on calcium/vitamin D supplementation).

RESULTS

Of the 29 patients with CHPA, prospective data were available for 26 patients undergoing 30 CHPA procedures (9 patients with MEN 1, 4 with MEN 2A, 1 with MEN 2B, and 12 with sporadic hyperparathyroidism). The mean follow-up interval was 2 years. Twelve of 26 patients (46%) had completely functional grafts, 6 patients (23%) had partially functional grafts, and the remaining 8 patients (31%) had nonfunctional grafts. No patient with CHPA had graft-dependent recurrent hyperparathyroidism. Of the 14 patients (15 autografts) with MEN, 7 patients (50%) had fully functional grafts, and 2 patients (14%) had partially functional grafts. The mean cryopreservation period was 7.9 months (range, 1 week to 22 months) for functional autografts and 15.3 months (range, 2 weeks to 106 months) for nonfunctional autografts (P < .01).

CONCLUSIONS

Based on these data and those in previous studies, approximately 60% of delayed, cryopreserved parathyroid autografts are functional. In this study 40% autografts (46% of patients) achieved full competency off supplements. Some patients have evidence of graft function with normal PTH levels but are not normocalcemic. Results were similar for patients with MEN and nonhereditary hyperparathyroidism. The duration of cryopreservation was a significant indicator of graft failure, and no functional autograft was observed beyond 22 months of preservation. CHPA is a useful treatment modality for patients with postoperative hypocalcemia after thyroid or parathyroid surgery, who do not respond to immediate parathyroid autotransplantation.

Parathyroid graft function after presternal subcutaneous autotransplantation for renal hyperparathyroidism

HYPOTHESIS

Presternal subcutaneous autotransplantation of parathyroid tissue after total parathyroidectomy for renal hyperparathyroidism could be at least as effective as intramuscular grafting, without its complications.

DESIGN

Prospective study of a postoperative diagnostic method of monitoring intact parathyroid hormone (iPTH) levels among a cohort of surgical patients, without loss to follow-up.

SETTING

Hemodialysis unit in a university hospital.

PATIENTS

Twenty-five patients (17 women and 8 men) underwent total parathyroidectomy and presternal subcutaneous autotransplantation for renal hyperparathyroidism at Donostia Hospital, San Sebastián, Spain, between January 1, 2002, and June 30, 2004.

MAIN OUTCOME MEASURES

Evaluation of parathyroid graft function by measurement of serum iPTH levels at admission and 24 hours and 1, 3, 5, 15, 30, and 60 weeks after surgery.

RESULTS

The mean +/- SD preoperative serum iPTH level was 1302 +/- 425 pg/mL; the iPTH level was undetectable in all patients 24 hours after surgery. Subsequent mean +/- SD iPTH levels obtained were 14 +/- 10 pg/mL after 1 week, 54 +/- 1 pg/mL after 5 weeks, 64 +/- 9 pg/mL after 15 weeks, 77 +/- 8 pg/mL after 30 weeks, and 106 +/- 21 pg/mL after 60 weeks. Autotransplanted parathyroid tissue appears to be adequately functional at week 5 (criterion level of adequate functioning, 50 pg/mL).

CONCLUSIONS

Presternal subcutaneous autotransplantation after total parathyroidectomy for renal hyperparathyroidism may be an alternative to avoid musculus brachialis grafting and its complications. Our functional results compare favorably with the published data on other surgical techniques for the treatment of renal hyperparathyroidism. Long-term follow-up of this series is planned.

Parathyroidectomy in secondary hyperparathyroidism: Is there an optimal operative management?

BACKGROUND

Subtotal parathyroidectomy (SPTX) and total PTX with autotransplantation (TPTX + AT) are both accepted operations for secondary hyperparathyroidism (2HPT). Studies have shown the 2 procedures to have similar rates of recurrent or persistent HPT (0% to 10%). The majority of these reports are small case series and despite apparently similar outcomes; the optimal operative management for 2HPT remains controversial. The purpose of this study was to determine whether there were any clinical outcome differences between these apparently comparable operations.

METHODS

A meta-analysis of 53 publications on reoperative operation for 2HPT from 1983 to 2004 identified 501 patients who had undergone an operation for recurrent or persistent 2HPT. The data evaluated included the type of initial operation, the need for reoperative operation as it related to the type of initial operation, and the intraoperative findings.

RESULTS

The initial operation had been a SPTX in 36% and a TPTX + AT in 64% of patients. Reoperative operation was for persistent 2HPT in 82 of 485 (17%) and for recurrent 2HPT in 403 of 485 (83%) patients. Findings at reoperation included: autograft hyperplasia (49%), supernumerary glands (20%), remnant hyperplasia (17%), a missed in situ gland (7%), and a negative exploration (5%). Supernumerary glands, missed in situ glands, and negative explorations occurred at equal rates for both operations. Reoperation determined that inadequate cervical explorations occurred in 42% of patients who had undergone a SPTX and in 34% of patients who had undergone a TPTX + AT.

CONCLUSIONS

Operative failures occur because of the limitations in preoperative localization, inadequate exploration, and the natural history of hyperplastic parathyroid tissue. The initial operation should include an attempt to localize supernumerary glands both pre- and intra-operatively.

Intraoperative monitoring of intact PTH in surgery for renal hyperparathyroidism as an indicator of complete parathyroid removal

In the setting of total parathyroidectomy and autotransplantation surgery (TPT x AS) as treatment for secondary hyperparathyroidism (SHPT), we evaluated whether intraoperative parathyroid hormone (iPTH) monitoring is useful as a reference for total parathyroid removal. We conducted a prospective, open, single value measurement efficacy study of the intraoperative (i.o.) diagnostic monitoring of iPTH in a cohort of surgical patients. All patients (n = 25) underwent TPT x AS at the Department of Surgery, Donostia Hospital from January 2002 to October 2004. The primary outcome measures were kinetics of serum levels of iPTH during surgery and prediction time of the of descent of PTH levels (measured in the clinic on the day of admission and intraoperatively during induction of anesthesia, every 5 and 10 minutes after removal of the adenoma, and again 24 hours thereafter). iPTH levels returned to normal in all 25 patients, decreasing from pathological levels at the beginning of the operation (1302.24 + 424.9 pg/ml) to half (50%) values at the third intraoperative determination, minute 10 (614.8 +/- 196.62), becoming undetectable at 24 hours. Frozen sections were conclusive for parathyroid tissue (20.56 + 10.3 minutes after removal). Intraoperative measurement of iPTH is useful in the prediction complete removal of all parathyroid tissue prior to autotransplantation, thus avoiding persistence of disease because of incomplete surgery.

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.

Treatment of osteoporosis with TheraCyte-encapsulated parathyroid cells: a study in a rat model

INTRODUCTION

The purpose of this study was to evaluate parathyroid function at monthly intervals following the implantation of TheraCyte-encapsulated live human parathyroid cells into ovariectomized rats and to determine the effect on bone mineral density (BMD) 4 months after ovariectomy ( 3 months after implantation).

METHODS

Parathyroid tissues were obtained from patients undergoing surgery for secondary hyperparathyroidism. In total, 21 Sprague-Dawley rats divided randomly into three groups were subjected to one of three treatments: (1) implanted with TheraCyte A-encapsulated 4x10(6) live parathyroid cells; (2) implanted with TheraCyte B-encapsulated 4x10(5) live parathyroid cells; (3) a sham operation; the control group. Rats were ovariectomized 1 month prior to the implantation of the TheraCyte. Blood was drawn at the time of implantation and at monthly intervals thereafter for 3 months to check the levels of calcium, phosphorus and intact parathyroid hormone (iPTH). The BMD of the lumbar spine (L1-L5) and of the left femoral bone was measured with dual-energy-X-ray absorptiometry (DEXA) 1 month after ovariectomy and 3 months after implantation of the TheraCyte (4 months after ovariectomy).

RESULTS

We found that the viability ratio of cryopreserved tissues was between 55 and 79% after thawing. In the control group, the BMD of the lumbar spine (L1-L5) had not decreased significantly (p=0.237) nor had the BMD of the left femoral bone increased significantly (p=0.063) 3 months after implantation. In the TheraCyte A group, the BMD of both the lumbar spine (p=0.018) and left femoral bone (p=0.018) had increased significantly 3 months after implantation. In the TheraCyte B group, the BMD of both the lumbar spine (p=0.017) and the left femoral bone (p=0.025) had also increased significantly 3 months after implantation. Serum iPTH levels were higher in the TheraCyte A group than in the TheraCyte B group (p=0.006), and higher in the TheraCyte B group than in the control group (p=0.040). Serum calcium levels were not significantly higher in the TheraCyte group A than in the TheraCyte B group or in the control group. Serum phosphorus levels were not significantly different between the TheraCyte A and TheraCyte B groups.

CONCLUSIONS

Implantation of TheraCyte A-encapsulated 4x10(5) live parathyroid cells and TheraCyte B-encapsulated 4x10(6) cells can increase the BMD of ovariectomized rats within 3 months of implantation. Neither cause high serum calcium and low phosphorus concentrations.

Definitive treatment for persistent hypoparathyroidism in a kidney transplant patient: parathyroid allotransplantation

Post-surgical hypocalcemia is usually a transitory complication in thyroid and parathyroid surgery that can be resolved quickly, although it becomes a delicate matter when the problem persists. Parathyroid transplantation is the choice of treatment; however, the associated immunosuppression can cause side effects. The following case study shows the transplantation of parathyroid tissue from a patient with secondary hyperparathyroidism to another kidney transplant patient with severe hypocalcemia that was medically intractable. The graft is functioning after 2 years.

Recovery of parathyroid function after total thyroidectomy: Long-term follow-up study

BACKGROUND

To prevent postoperative hypoparathyroidism following total thyroidectomy, the parathyroid glands are preserved in situ and/or resected or devascularized parathyroid glands are autotransplanted. A retrospective investigation was conducted utilizing biochemical and specific endocrine assessments to evaluate the difference in recovery of parathyroid function in the long term.

METHODS

A total of 103 patients underwent total thyroidectomy at Second Department of Surgery, School of Medicine, Kagawa University between 1990 and 1998. These patients were divided into a preservation group (n = 17), with only preserved glands in situ; a combination group (n = 72), consisting of patients with one or more parathyroid glands preserved in situ and one or more autotransplanted parathyroid glands; and an autotransplantation group (n = 14), with only transplanted glands.

RESULTS

The overall incidence of permanent hypoparathyroidism in the preservation group, the combination group, and the autotransplantation group was 0%, 1.4%, and 21.4%, respectively. The mean levels of intact parathyroid hormone in the preservation group, the combination group, and the autotransplantation group recovered to 102%, 107%, and 50% of the preoperative levels at 5-year follow up.

CONCLUSION

The results of the present study suggest that parathyroid glands should be preserved in situ whenever possible, to promote better recovery of postoperative function, and that only autotransplantation produces inadequate recovery of long-term function.

Parathyroid Autotransplantation during Total Thyroidectomy—Does the Number of Glands Transplanted Affect Outcome?

Parathyroid autotransplantation is a technique for ensuring the continued function of parathyroid tissue at the time of total thyroidectomy (TT). The aim of this study was to ascertain whether the number of parathyroids transplanted affects the incidence of temporary and permanent hypoparathyroidism. A retrospective cohort study included all patients undergoing a TT in a single unit between July 1998 and June 2003. The number of parathyroids transplanted, the final pathology, and the incidence of temporary and permanent hypoparathyroidism were documented. Fisher's exact test was used for statistical analysis. A total of 1196 patients underwent a TT during the 5 years studied. Of these, 306 (25.6%) had no parathyroids transplanted, 650 (54.3%), 206 (17.2%), 34 (2.8%) had 1,2, or 3 glands autotransplanted, respectively. The incidence of temporary hypoparathyroidism was 9.8% for no gland transplants, 11.9%, 15.1%, and 31.4% for 1,2,and 3 gland transplants, respectively (p < 0.05). The incidence of permanent hypoparathyroidism was 0.98%, 0.77%, 0.97%, and 0%, respectively (p = NS). The incidence of temporary hypoparathyroidism was higher when surgery was performed for Graves' disease. Temporary hypocalcemia is closely related to the number of autotransplanted parathyroids during TT. The long-term outcome is not affected by the number of parathyroids autotransplanted. A "ready selective" approach to parathyroid autotransplantation is an effective strategy for minimizing the rate of permanent hypoparathyroidism.

A new animal model to assess angiogenesis and endocrine function of parathyroid heterografts in vivo

BACKGROUND

It is still a matter of investigation how angiogenesis and restoration of gland perfusion determine graft function after free parathyroid autotransplantation. We provide a new animal model allowing simultaneous and repetitive in vivo assessment of angiogenesis and endocrine function of parathyroid transplants.

METHODS

Fresh human parathyroid tissue from patients with secondary hyperparathyroidism was grafted into dorsal skinfold chamber preparations of athymic nude mice (CD1-nu; n=8). Equivalent pieces of the same human donor specimens were heat-inactivated and served as control grafts (n=7).

RESULTS

In all animals receiving parathyroid transplants, intact human parathyroid hormone levels were detectable by species-specific enzyme-linked immunosorbent assay analysis of plasma samples on day 5 after transplantation and increased by 2.5-fold over the observation period (19 days) in contrast with controls. Plasma Ca levels revealed no differences between the groups. On day 5 after transplantation, intravital fluorescence microscopy revealed murine angiogenic microvessels sprouting along nonperfused human donor vessels, and 1 week later functional microvasculature was established in all parathyroid transplants. Histologic analysis revealed well-vascularized endocrine tissue. In contrast, control grafts were necrotic and partly resorbed; they exhibited no angiogenic activity or well-vascularized fat cells indicating fatty degeneration. In addition, species-specific Western blot analysis revealed vascular endothelial growth factor expression of parathyroid transplants rather than functional vessel density as the functional parameter of angiogenesis determining transplant function in vivo.

CONCLUSION

This model may serve to understand mechanisms associated with specific parathyroid transplant angiogenesis and its significance for transplant function to optimize clinical success of autotransplantation in therapy-resistant patients.

Direct Revascularization is Superior for Rat Parathyroid Allotransplantation with Fk506

Parathyroid gland allotransplantation has been a challenging goal for decades. Our objective was to optimize a parathyroid allotransplantation model for analysis of short-term or low-dose immunosuppressive regimens. Rats that had undergone parathyroidectomy received parathyroid allografts either by direct microvascular anastomoses as part of a composite laryngotracheal graft or by direct implantation into hind limb muscle. All rats were maintained on daily low-dose FK506 (tacrolimus). Intact serum parathyroid hormone (PTH) levels for both groups were recorded over a period of at least 45 days and compared with a repeated-measures mixed model. We found that microvascular anastomosis was superior to implantation for parathyroid gland survival, as all revascularized grafts immediately produced normal levels of PTH, whereas implanted grafts had a significantly slower recovery of function (p < .001). Four of the 11 implanted grafts (36%) never produced detectable PTH levels. Using this model, we are developing innovative strategies that will lead to successful parathyroid allotransplantation without the need for chronic immunosuppression.

Surgical Indications and Procedures of Parathyroidectomy in Patients with Chronic Kidney Disease

The Kidney Foundation of the USA proposed clinical practice guidelines for bone metabolism and disease in chronic kidney disease including parathyroidectomy (PTx). We performed PTx in a total of 1725 patients with advanced secondary hyperparathyroidism (2HPT) and evaluated the K/DOQI guideline concerning PTx, comparing it with our surgical strategy. The guidelines emphasize the avoidance of ectopic calcification and cardiovascular complications which may be induced by hypercalcemia, hyperphosphatemia, and persistent high parathyroid hormone level. We agree with the attitude of the K/DOQI guideline. To decide surgical indications, we emphasize that the size of parathyroid gland is one of the important factors. The guideline recommends subtotal PTx and total PTx with autotransplantation. We prefer total PTx with forearm autograft, mainly because it is easier and safer to remove the residual parathyroid tissue from the forearm at recurrence compared to neck re-exploration. In Japan, almost all patients require long-term hemodialysis after PTx because of the very small opportunity of kidney transplantation. The risk of recurrence is not negligible. Based on our huge experience we believe our strategy for advanced secondary hyperparathyroidism can be accepted at least in Japan.

Intraoperative Intact Parathyroid Hormone Level Monitoring as a Guide to Parathyroid Reimplantation after Thyroidectomy

OBJECTIVE

The goal of this study was to determine whether intraoperative intact parathyroid hormone (IOiPTH) levels can predict the functional status of remaining parathyroids at the end of total thyroidectomy and thereby be a guide for parathyroid autotransplantation when glands are deemed not functional.

STUDY DESIGN

Prospective study involving 23 patients undergoing either total thyroidectomy or completion thyroidectomy

METHODS

During surgery, an attempt was made to identify all four parathyroid glands. Normal size vascular glands were preserved, whereas avascular glands were microdissected and reimplanted. Serial IOiPTH was measured preoperatively after each parathyroid was identified, manipulated, or removed and serum iPTH measurements were done postoperatively up to 56 days.

RESULTS

The sensitivity of low IOiPTH in identifying a devascularized gland was 88.9%, and specificity was 92.9%. A normal IOiPTH level indicates at least two functioning glands. IOiPTH levels between 1.5 and 10 pg/mL indicate only one functional gland. Undetectable IOiPTH levels indicate no residual functioning gland.

CONCLUSIONS

For patients undergoing total or completion thyroidectomy, IOiPTH should be routinely measured at the end of the procedure, and a level less than 10 pg/mL requires reassessment of remaining parathyroid glands. Vascularized glands should be preserved regardless of IOiPTH levels. Devascularized glands or glands of questionable vascularity should be considered for autotransplantation.

Cervical epidural anesthesia for combined neck and upper extremity procedure: a pilot study

In a prospective pilot study, we evaluated the possibility of performing a total parathyroidectomy with parathyroid gland implantation into the forearm (a combined neck and upper extremity procedure) under cervical epidural anesthesia (CEA) at C6-7 level using ropivacaine. The indication for CEA was the patient's choice or a previous procedure on the neck with unilateral vocal cord paralysis. Anesthesia was induced by 10 mL of 0.75% ropivacaine plus 10 mug of sufentanil in 2 mL. Block onset time, success rate, analgesia, sensory block extent, changes in respiratory and hemodynamic variables, complications, and length of hospital stay were assessed. All 15 procedures were successfully performed under CEA. Sensory block was registered in the range C2-T10, with a lower median of T3. The upper margin of sensory block was C2 in all patients. Of the respiratory variables, the only significant decrease was observed in forced vital capacity; none of the patients developed clinically significant respiratory insufficiency. We conclude that combined procedures involving the neck and upper limbs can be performed using CEA with ropivacaine. CEA allows verbal communication with patients and early detection of vocal cord paralysis.

Persisted/recurrent hyperparathyroidism associated with development of multi-drug resistance phenotype and proliferation of parathyroid transplants

The surgical treatment of secondary hyperparathyroidism (HPTH) requires sub-total excision of parathyroid glands or total excision with their autotransplantation. Although this approach has been considered as a safe method of treatment, in this report we describe persisted/recurrent HPTH after parathyroid transplantation. Due to parathormone (PTH) hypersecretion and uncontrolled proliferation, the parathyroid grafts were removed and used for generation of cell cultures, which further have been subjected to in vitro studies. As a control we used parathyroid tissue, obtained during multiorgan harvesting. We found increased proliferation and up-regulated PTH production by the graft-derived, but not control in vitro cultured cells. Moreover, due to decrease of in vivo radiotracer uptake by parathyroid grafts, the expression of multi-drug resistance-involved factors, including P-glycoprotein (P-gp/mdr1), multi-drug resistance-associated protein (mrp) and bcl-2 have been investigated using RT-PCR. The analysis revealed increased expression of both, mdr1 and mrp in graft-derived cells, in contrast to control cells, which did not express P-gp/mdr1 or mrp. However, we did not observe any difference in expression of bcl-2 between analyzed cells. The up-regulated expression of P-gp/mdr1 on graft-derived cells was further confirmed by immunofluorescence studies. The described case indicates potential risk associated with transplantation of parathyroid tissue. Our results confirm a role of MDR phenomenon in occurrence of false negative results in parathyroid tissue scintigraphy studies. Moreover, they indicate that standard histological examination of transplanted material could not be sensitive enough to exclude any potential danger of abnormal graft progression. Thus, they could support the concept to use encapsulated parathyroid transplants.

[Parathyroidectomy for advanced renal hyperparathyroidim in hemodialysis]

Treatment of advanced secondary hyperparathyroidism should be shifted from to avoid progression of bone disease to protection of cardiovascular complications induced by ectopic calcification. Patients who suffer from advanced secondary hyperparathyroidism with uncontrollable hypercalcemia or/and hyperphosphatemia by medical treatment should be referred to surgical treatment at relatively early time. Total parathyroidectomy with forearm autograft is adequate operative procedure especially in patients who require long-term hemodialysis.

Microencapsulation of parathyroid tissue with photosensitive poly(L-lysine) and short chain alginate-co-MPEG

Human parathyroid glands were encapsulated using the alginate-PLL system in this study. In order to improve the mechanical strength and the biocompatibility, the microcapsules were fabricated with a three-layer structure that consisted of alginate/photosensitive poly(L-lysine)/short chain alginate-co-MPEG. These modified microcapsules were used for encapsulating human parathyroid tissue. In vitro experiments revealed that microencapsulated parathyroid glands maintained differentiative properties in culture, and the capsular membrane was freely permeable to the human parathyroid hormone. For in vivo experiments, these capsules were transplanted into parathyroidectomized SD-rats. After parathyroidectomy, serum calcium decreased from 2.25 to 1.68 mmol/L and remained in a constantly low concentration until transplantation. Parathyroidectomized SD-rats were normocalcemic after transplant of encapsulated parathyroid tissue. The microcapsules were then explanted at 12 weeks for examination. Histological evaluations of excised transplants revealed that the microcapsules remained intact structurally and were free of cell adhesions. The results demonstrated that human parathyroid tissue microencapsulated by this system retains stability and is functional both in vitro and in vivo. This encapsulating system will have valuable application for endocrine surgery in the future.

Usefulness of Radio-guided Surgery Using Technetium-99m Methoxyisobutylisonitrile for Primary and Secondary Hyperparathyroidism

The efficacy of technetium-99m methoxyisobutylisonitrile (99mTc-MIBI)-guided surgery for detecting abnormal parathyroid glands in patients with secondary hyperparathyroidism (2-HPT) was evaluated and compared with the results from the same examination in patients with primary hyperparathyroidism (1-HPT). The results were also compared with those found by ultrasonography (US) and preoperative 99mTc-MIBI scintigraphy was also made. At operation 99mTc-MIBI accumulated in 64 nodules of 15 cases of 2-HPT, and all of 60 parathyroid swellings were detected (true-positives 60, sensitivity 100%, accuracy 94%). In the cases of 1-HPT, 99mTc-MIBI revealed 11 hot nodules in 10 cases, and the evaluation was true-positive 10, sensitivity 100%, and accuracy 91%. US and preoperative 99mTc-MIBI scintigraphy in patients with 2-HPT had a sensitivity of 75% and 67% and an accuracy of 70% and 66%, respectively. The usefulness of 99mTc-MIBI-guided surgery for detecting abnormal parathyroid tissue in 2-HPT patients was similar to that in 1-HPT patients but was superior to US and preoperative 99mTc-MIBI scintigraphy. Intraoperative 9mTc-MIBI for patients with 2-HPT is effective and makes the surgery easier, especially when the parathyroid glands are ectopic or when a few glands are markedly enlarged but the other glands are atrophied.