Leyre Lorente-Poch

Importance of in situ preservation of parathyroid glands during total thyroidectomy

Parathyroid failure is the most common complication after total thyroidectomy but factors involved are not completely understood. Accidental parathyroidectomy and parathyroid autotransplantation resulting in fewer than four parathyroid glands remaining in situ, and intensity of medical treatment of postoperative hypocalcaemia may have relevant roles. The aim of this study was to determine the relationship between the number of parathyroid glands remaining in situ and parathyroid failure after total thyroidectomy.

Defining the syndromes of parathyroid failure after total thyroidectomy.

Acute and chronic parathyroid insufficiency syndromes are the most common complication after total thyroidectomy. Permanent hypoparathyroidism imposes an important medical burden on patient lifestyle due to the need for lifetime medication, regular visits and significant long-term costs. Its true prevalence has been underestimated due to lack of clear definitions, inadequate follow-up and conflicts of interest when reporting individual patient series. The aim of this review is to propose precise definitions for the different syndromes associated to parathyroid failure based on the follow-up and management of patients developing hypocalcemia (<8 mg/dL at 24 hours) after first-time total thyroidectomy for cancer or goiter at our unit. Short and long-term post-thyroidectomy parathyroid failure presents as three different metabolic syndromes: (I) postoperative hypocalcemia is defined as a s-Ca <8 mg/dL (<2 mmol/L) within 24 hours after surgery requiring calcium/vit D replacement therapy at the time of hospital discharge; (II) protracted hypoparathyroidism as a subnormal iPTH concentration (<13 pg/mL) and/or need for calcium/vit D replacement at 4-6 weeks; and (III) permanent hypoparathyroidism as a subnormal iPTH concentration (<13 pg/mL) and/or need for calcium/vit D replacement 1 year after total thyroidectomy. Each of these syndromes has its own pattern of recovery and should be approached with different therapeutic strategies.

Inadvertent parathyroidectomy during total thyroidectomy and central neck dissection for papillary thyroid carcinoma.

Background. The main drawback of central neck lymph node dissection is postoperative parathyroid failure. Little information is available concerning inadvertent resection of the parathyroid glands in this setting and its relationship to postoperative hypoparathyroidism. Our aim was to determine the prevalence of inadvertent parathyroidectomy during total thyroidectomy and central neck dissection for papillary thyroid cancer and its impact on short‐and long‐term parathyroid function. Methods. This was a prospective observational study of consecutive patients undergoing first‐time total thyroidectomy with a central neck dissection for papillary carcinoma >10 mm. Prevalence and risk factors for inadvertent parathyroidectomy were recorded. Serum calcium and intact parathyroid hormone concentrations were determined 24 hours after operation and then periodically in patients developing postoperative hypocalcemia. All patients were followed for a minimum of one year. Results. Whole gland (n = 33) or microscopic parathyroid fragments (n = 14) were identified in 47/170 (28%) operative specimens. The lower parathyroid glands were involved more often. Variables influencing inadvertent parathyroidectomy were extrathyroidal extension of the tumor and therapeutic lymphadenectomy. Neither lateral neck dissection nor the number of lymph nodes retrieved affected the rate of inadvertent parathyroid resection. Postoperative hypocalcemia and permanent hypoparathyroidism were more frequent after inadvertent parathyroidectomy (64% vs 46% and 15% vs 4%; P ≤ .03 each). Conclusion. Inadvertent parathyroidectomy during total thyroidectomy with central neck dissection for papillary thyroid carcinoma is common and involves the inferior glands more frequently in patients with extended resections and clinical N1a disease. Inadvertent resection of parathyroid glands is associated with greater rates of postoperative hypocalcemia and permanent hypoparathyroidism.

TIME TO PARATHYROID FUNCTION RECOVERY IN PATIENTS WITH PROTRACTED HYPOPARATHYROIDISM AFTER TOTAL THYROIDECTOMY

OBJECTIVE Hypocalcaemia is the most common adverse effect after total thyroidectomy. It recovers in about two-thirds of the patients within the first postoperative month. Little is known, however, about recovery of the parathyroid function (RPF) after this time period. The aim of the present study was to investigate the time to RPF in patients with protracted (>1 month) hypoparathyroidism after total thyroidectomy. DESIGN Cohort prospective observational study. METHODS Adult patients undergoing total thyroidectomy for goitre or thyroid cancer. Cases with protracted hypoparathyroidism were studied for RPF during the following months. Time to RPF and variables associated with RPF or permanent hypoparathyroidism were recorded. RESULTS Out of 854 patients undergoing total thyroidectomy, 142 developed protracted hypoparathyroidism. Of these, 36 (4.2% of the entire cohort) developed permanent hypoparathyroidism and 106 recovered: 73 before 6 months, 21 within 6-12 months and 12 after 1 year follow-up. Variables significantly associated with RPF were the number of parathyroid glands remaining in situ (not autografted nor inadvertently resected) and a serum calcium concentration >2.25 mmol/L at one postoperative month. Late RPF (>6 months) was associated with surgery for thyroid cancer. RPF was still possible after one year in patients with four parathyroid glands preserved in situ and serum calcium concentration at one month >2.25 mmol/L. CONCLUSIONS Permanent hypoparathyroidism should not be diagnosed in patients requiring replacement therapy for more than six months, especially if the four parathyroid glands were preserved.

A nomogram to predict the likelihood of permanent hypoparathyroidism after total thyroidectomy based on delayed serum calcium and iPTH measurements

Background Retrospective studies have shown that delayed high-normal serum calcium and detectable iPTH are independent variables positively influencing outcome of prolonged parathyroid failure after total thyroidectomy (TT). The aim of the present study was to examine prospectively the ability of these two variables to predict permanent hypoparathyroidism in patients under replacement therapy for postoperative hypocalcemia. Methods Prospective observational multicenter study of patients undergoing TT followed by postoperative parathyroid failure (serum calcium <8 mg/dL within 24 h and PTH <15 pg/mL 4 h after surgery). Serum calcium, vitamin D and iPTH were determined before thyroidectomy, 24 h after surgery, at 1 month and then periodically until recovery of the parathyroid function or permanent hypoparathyroidism was diagnosed after at least 1 year follow-up. Results Some 145 patients with postoperative hypocalcemia were investigated [s-Ca24h 7.5 (0.5) mg/dL]. Hypocalcemia recovered within 30 days in 91 (63%) patients and 54 (37%) developed protracted hypoparathyroidism {iPTH 5.8 [4] pg/mL at 1 month}, of whom 32 recovered within 1 year and 22 developed permanent hypoparathyroidism. Protracted hypoparathyroidism was related to few parathyroid glands remaining in situ (PGRIS). Serum calcium concentration (mg/dL) at 1 postoperative month correlated positively with the rate of recovery (percent) from protracted hypoparathyroidism: <8.5 (20%); 8.5-9 (29%); 9.1-9.5 (70%); 9.6-10 (89%); >10 (83%) (P=0.013). Serum iPTH at 1 month was also higher (7.3 vs. 3.7 pg/mL; P=0.002) in recovered protracted hypoparathyroidism. The combination of both variables predicts the likelihood of recovery of the parathyroid function with >90% accuracy. Conclusions High-normal serum calcium and low but detectable iPTH concentrations at 1 month after TT were associated with better outcome of protracted hypoparathyroidism. A nomogram combining both variables may guide medical treatment and monitoring of post-thyroidectomy prolonged hypoparathyroidism.

Esophageal recurrence of medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) metastasizes to the regional lymph nodes and to the lungs, liver and bones. Only one case of recurrence of MTC involving the upper gastrointestinal tract has been reported so far. We describe the case of a 38-year-old woman with MTC, who developed an upper esophageal submucosal recurrence after two previous local recurrences treated surgically and one ethanol injection. After resection of the right lateral esophageal wall, calcitonin dropped by 60% and showed a doubling time >1 year. We cannot rule out the role of deep ethanol injection in the involvement of the cervical esophagus wall.

Undescended parathyroid adenomas as cause of persistent hyperparathyroidism

BACKGROUND Undescended glands are a rare cause of primary and secondary hyperparathyroidism (HPT), but they are more common, however, among patients with recurrent HPT or those who have undergone a failed initial cervical exploration. The currently development of more precise noninvasive imaging techniques has improved the results of preoperative diagnosis of these ectopic lesions. METHODS The operative reports of patients undergoing parathyroidectomy at our institution were reviewed to identify patients with an undescended parathyroid gland adenomas. Demographic, clinical, imaging and surgical variables were recorded. RESULTS Three patients were included: 2/598 parathyroidectomies performed for primary HPT and 1/93 performed for secondary HPT. One case is presented as jaw tumor syndrome (JTS). All the patients had undergone at least one operation before the definitive focused surgery and represented 6% of our parathyroid reoperations. No significant complications and no recurrences were observed in the long-term follow up. CONCLUSIONS Accurate preoperative localization of these lesions was possible with noninvasive studies. High cure rate is possible through selective approach when accurate preoperative localization. Thorough knowledge of parathyroid embryology and meticulous surgical technique are essential, particularly in patients with previous unsuccessful explorations.

Parathyroid autotransplantation in thyroid surgery

BackgroundCareful parathyroid gland dissection and in situ preservation was the time-honored approach to prevent parathyroid failure after total thyroidectomy. The relative success of parathyroid autotransplantation of hyperplastic parathyroid tissue in patients with renal or hereditary hyperparathyroidism did popularize the use of normal parathyroid tissue autografts during thyroidectomy to prevent permanent hypoparathyroidism. Proof of autograft function in this setting, however, is controversial.PurposeThis narrative review aims at reviewing critically the current status of parathyroid autotransplantation during total thyroidectomy. It is also meant to analyze from the historical, methodological, and clinical points of view the claimed benefit of normal parathyroid gland autotransplantation. A focus is placed on the prevention of permanent hypoparathyroidism by parathyroid autotransplantation.ConclusionsLiberal parathyroid autotransplantation was proposed in the mid 1970s but evidence of function is scarce. Proofs are accumulating that parathyroid autografts not only increase the rate of postoperative hypocalcemia, but may be also contribute to permanent hypoparathyroidism.