Recovery Of Parathyroid Function Research Articles

Vitamin D Deficiency Reduces Postthyroidectomy Protracted Hypoparathyroidism Risk. Is Gland Preconditioning Possible?

Hypoparathyroidism is the most frequent complication after total thyroidectomy (PT-hypoPTH). After 1 year, most patients recover parathyroid function; however, the implicated physiologic dynamics remain unknown. Vitamin D deficiency (VDD) is the main cause of secondary hyperparathyroidism. Whether this compensatory hyperparathyroidism could influence parathyroid function recovery (PFR) in the setting of PT-hypoPTH has not been studied. This work aimed to evaluate the effect of preoperative VDD on PFR. A retrospective study was conducted with a prospectively maintained database including patients undergoing a total thyroidectomy between May 2014 and June 2019. Preoperative vitamin D (25(OH)D) less than 20 mg/mL was defined as VDD. Intact PTH less than 14 pg/mL on postoperative day 1 was defined as PT-hypoPTH. Transient PT-hypoPTH displayed PFR within the first year (early recovery: < 30 days; protracted recovery: > 30 days) whereas definite PT-hypoPTH did not. Survival analysis evaluated the effect of preoperative VDD on PFR, and a binary logistic regression model identified associated factors. A total of 397 patients were identified. The observed rates of transient, protracted, and definite PT-hypoPTH were 32.9%, 15.1%, and 5.2%, respectively. Rates of VDD were higher in the early-recovery PT-hypoPTH group (55.2% vs 31.5%; P = .01). Preoperative VDD was associated with faster PFR (19 vs 35 days; P = .03) and behaved as a protective factor for protracted PT-hypoPTH (odds ratio 0.47; 95% CI, 0.25-0.881; P = .016) in the multivariable analysis. Preoperative VDD could act as a preconditioning factor of the parathyroid glands prior to the surgical aggression exerted against them during surgery aiding PFR. Basic research studies and prospective clinical trials are needed to explain the underlying physiological mechanisms and to provide further evidence to improve clinical management.

The Effects of Radioiodine Therapy on the Recovery of Parathyroid Function in Patients with Protracted Hypoparathyroidism after Total Thyroidectomy for Papillary Thyroid Carcinoma

Background To determine the effect of 131I treatment on postoperative parathyroid function and the timing of recovery of parathyroid function (RPF) in patients with protracted hypoPT. Methods 260 patients with papillary thyroid cancer (PTC) were retrospectively analyzed, including 166 patients treated with radioactive iodine-131 (131I) classified into the 131I group and 94 patients without 131I treatment classified into the control group. Data on clinicopathological characteristics, demographics, dose and interval time of 131I treatment, number of parathyroid glands remaining in situ (PGRIS), occurrence of hypoPT, duration of RPF, preoperative and postoperative levels of Ca and PTH were collected. Results The patients in the 131I group showed a higher persistent hypoPT rate than those in the control group (p = 0). The PGRIS and total number of PG were significantly higher in patients who recovered from protracted HypoPT (p = 0.02; p = 0.03). PGRIS and 131I treatment [1 ∼ 2 VS 0, p = 0.03, OR 3.19; 3 ∼ 4 VS 0, p = 0.02, OR3.62; p = 0.02, OR 1.98, respectively] were independent factors influencing postoperative persistent hypoPT. The timing of RPF differed significantly for patients in the control group compared to those in the 131I group [p = 0.00]. Conclusions We found that 131I treatment significantly prolonged the RPF of patients with protracted hypoPT and caused late RPF (even beyond 12 months). The diagnosis of “permanent” hypoPT should be cautiously made at least 12 months after surgery, especially in patients who receive 131I treatment.

Does the number of autotransplanted parathyroid glands affect postoperative hypoparathyroidism and serum parathyroid hormone levels?

BackgroundTo investigate how number of autotransplanted parathyroid glands (PGs) affects the incidence of postoperative hypoparathyroidism and the recovery of parathyroid function. MethodsA systematic search was performed in the MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases. The evaluated indices included the incidence of postoperative transient and permanent hypoparathyroidism and parathyroid hormone (PTH) levels during follow-up. ResultsTwenty articles with 7291 patients were included. A higher incidence of transient hypoparathyroidism was found in the PG autotransplantation group than in the preservation group (odds ratio [OR]: 2.37; 95% confidence interval [CI]: 1.90, 2.96). However, there was no significant difference between the two groups regarding permanent hypoparathyroidism (OR: 1.17; 95% CI: 0.71, 1.91). Parathyroid hormone (PTH) levels in the PG autotransplantation group changed significantly more than the preservation group at postoperative 1-day and 1-month, but became similar at the 6-month, 1-year and 2-year follow-up. Autotransplantation of 2 and 3 PGs demonstrated a higher incidence of transient hypoparathyroidism than 1 PG (OR: 2.09; 95% CI: 1.41, 3.11 and OR: 9.70; 95% CI: 2.11, 44.39, respectively), but no significant difference was observed between the autotransplantation of 3 and 2 PGs (OR: 0.99; 95% CI: 0.03, 29.06). Additionally, the incidence of permanent hypoparathyroidism was not significantly different when different number of PGs was autotransplanted. ConclusionsPG autotransplantation is an effective mid- and long-term strategy for the preservation of parathyroid function. Although transient hypoparathyroidism was positively correlated with the number of autotransplanted PGs, no remarkable correlation was observed for permanent hypoparathyroidism.

Outcome of parathyroid function after total thyroidectomy when calcium supplementation is administered routinely versus exclusively to symptomatic patients: A prospective randomized clinical trial.

Current guidelines for calcium supplementation for parathyroid function recovery after thyroidectomy are based on low-quality evidence. The present trial compared the effects of oral calcium and vitamin D supplementation on the recovery of parathyroid function when administered routinely or exclusively to symptomatic patients. This prospective, randomized, open-label clinical trial analyzed 203 patients who underwent total thyroidectomy and developed hypoparathyroidism on postoperative day 1 (POD1) with median age of 41 years and proportion of women of 77.8%. Participants were randomized to group A (calcium and vitamin D supplementation administered only to symptomatic patients) and group B (routine supplementation). The primary outcome was the incidence of protracted hypoparathyroidism in the two groups. Secondary outcomes included risk factors for postoperative protracted hypoparathyroidism and the incidence of symptomatic hypocalcemia. The incidence of protracted hypoparathyroidism was not significantly different between group A and group B (11 of 99 vs. 17 of 104, P = 0.280). Parathyroid hormone (PTH) in group B exhibited a better recovery tendency. The incidence of postoperative symptomatic hypocalcemia in group B was significantly lower than group A (26.92% vs. 42.42%, P = 0.020). Independent factors predicting protracted hypoparathyroidism included sex, preoperative serum calcium, and POD1 PTH. Calcium and vitamin D supplementation administered exclusively to symptomatic patients achieved the same effect on protracted hypoparathyroidism as routine supplementation. However, routine supplementation significantly reduced postoperative hypocalcemia. Extra attention is necessary in female patients with high preoperative serum calcium and patients with low POD1 PTH. Chinese Clinical Trial Registry (ChiCTR), ChiCTR1900022194. Registered March 30, 2019.

Correction: Late Recovery of Parathyroid Function after Total Thyroidectomy: A Case-Control Study

Correction: Late Recovery of Parathyroid Function after Total Thyroidectomy: A Case-Control Study

Is There a Regular Pattern in the Recovery of Parathyroid Function After Thyroid Cancer Surgery?

PurposeTo investigate whether there is a pattern of recovery of parathyroid function after thyroid cancer surgery.Patients and MethodsThe study included 183 patients with papillary thyroid cancer (PTC) who underwent “total thyroidectomy (TT)” plus “unilateral central lymph node dissection (UCLND)” or “bilateral central lymph node dissection (BCLND)”. The intact parathyroid hormone (iPTH) and serum calcium (sCa) were analyzed several times within 1 month after surgery to explore the recovery pattern of parathyroid gland function. Then, these 183 cases were divided into group A (97 cases) with UCLND and group B (86 cases) with BCLND to analyze whether the impairment and recovery of parathyroid function were different between the two subgroups.ResultsPostoperative hypoparathyroidism was seen in 115 out of 183 cases. iPTH values decreased significantly on postoperative day (POD) 1 compared with preoperative values, dropped to the lowest point on POD 3, showed an increasing trend on POD 5 and 14, and increased to 85.0% of preoperative values at POD30, whereas changes in sCa differ from changes in iPTH, which showed the lowest sCa value on POD1, and rebounded on the POD3 with the intervention of calcium supplementation, and continued to rise on the POD5 and POD14, and the sCa value reached 96.6% of the preoperative level at POD30. Subgroup analysis showed that temporary hypoparathyroidism was more pronounced in group B than in group A. SCa and iPTH levels in both subgroups showed the same trend of first decrease and then increase.ConclusionThe recovery of hypocalcemia and hypo-iPTHemia in the first month after thyroid cancer surgery shows a trend of decreasing and then increasing, and knowing the recovery of parathyroid function at different time points is of great value to surgeons and patients alike.

Selective Parathyroid Autotransplantation During Total Thyroidectomy for Papillary Thyroid Carcinoma: A Cohort Study.

Purpose: The relationship between the selective parathyroid gland (PG) autotransplantation and hypoparathyroidism is still not completely clear. The aim was to ascertain whether the number of autotransplanted PGs affected the incidence of hypoparathyroidism and recovery of parathyroid function in the long-term for patients with papillary thyroid carcinoma (PTC).Methods: A retrospective cohort study included all patients with PTC who had underwent primary total thyroidectomy with central neck dissection between January 2013 and December 2017. The patients were divided into three groups (0, 1, and 2 PGs autotransplanted, respectively).Results: Of the 2,477 patients, 634 (25.6%) received no PG autotransplantation, 1,078 (43.5%) and 765 (30.9%) were autotransplanted 1 and 2 PGs, respectively, and the incidence of permanent hypoparathyroidism (>1 year) was 1.7%, 0.7%, and 0.4% (P = 0.0228). Both 1 or 2 PGs autotransplanted increased the incidence of transient biochemical hypoparathyroidism (odds ratio [OR], 1.567; 95% confidence interval [CI], 1.258–1.953; P < 0.0001; OR, 2.983; 95% CI, 2.336–3.810; P < 0.0001, respectively) but reduced the incidence of permanent hypoparathyroidism (OR, 0.373; 95% CI, 0.145–0.958; P = 0.0404; OR, 0.144; 95% CI, 0.037–0.560; P = 0.0052, respectively). Both 1 or 2 PGs autotransplanted did not independently influence the occurrence of hypocalcemia symptoms.Conclusion: Selective parathyroid autotransplantation is less likely to lead to post-operative symptomatic hypocalcemia, although it could lead to a transient decrease in parathyroid hormone. However, in the long run, it is still an effective strategy to preserve parathyroid function.

Does the number of parathyroid glands autotransplanted affect the incidence of hypoparathyroidism and recovery of parathyroid function?

BackgroundThe relationship between the number of parathyroid glands autotransplanted and hypoparathyroidism as well as recovery of parathyroid function is not understood fully. The aim was to ascertain whether the number of autotransplanted glands affected the incidence of hypoparathyroidism and recovery of parathyroid function in long-term follow-up after thyroidectomy. MethodsA retrospective cohort study included all patients with papillary thyroid carcinoma who underwent first-time total thyroidectomy with central neck dissection between June 2012 and June 2015. The patients were divided into 4 groups (0, 1, 2, and 3) on the basis of the number of parathyroid glands autotransplanted. ResultsOf the 766 patients, 283 (36.9%) had no gland autotransplanted, and 373 (48.7%), 97 (12.7%), and 13 (1.7%) had 1, 2, and 3 glands autotransplanted, respectively. More lymph nodes and more metastatic ones in the central compartment were retrieved in groups 2 and 3 (P < .05). With increasing number of autotransplanted glands, the incidence of transient hypoparathyroidism was 26.1%, 36.2%, 52.6%, and 84.6% (P < .05), and the incidence of permanent hypoparathyroidism was 1.8%, 1.1%, 1.0%, and 0% (P > .05). The recovery rates of serum parathyroid hormone concentration were 84.7%, 82.2%, 82.0%, and 79.2% after 2-year follow-up (P > .05). ConclusionAutotransplantation is an effective strategy for restoration of parathyroid function. Transient hypoparathyroidism is positively correlated to the number of autotransplanted parathyroid glands during total thyroidectomy with central neck dissection. There is no increase in permanent hypoparathyroidism in patients with a higher number of autotransplanted glands, despite more extensive lymph node disease. (Surgery 2018;161:XXX-XXX.)

Effect of autotransplantation of a parathyroid gland on hypoparathyroidism after total thyroidectomy.

BackgroundThe effect of parathyroid autotransplantation on hypoparathyroidism is not fully understood. The purpose of the study was to determine the effect of autotransplantation of a parathyroid gland on the incidence of hypoparathyroidism and recovery of parathyroid function at 6 months after total thyroidectomy with central neck dissection for papillary thyroid carcinoma.MethodsAll patients with autotransplantation of a parathyroid gland (no inadvertent parathyroidectomy) (group A), in situ preservation of all parathyroid glands (no autotransplantation and inadvertent parathyroidectomy) (group B) or inadvertent removal of a parathyroid gland (no autotransplantation) (group C) who underwent first-time total thyroidectomy with central neck dissection for papillary thyroid carcinoma between January 2013 and June 2016 were included retrospectively.ResultsOf the 702 patients, 383, 297 and 22 were respectively included in the groups A, B and C. The overall rates of transient and permanent hypoparathyroidism were 37.6% and 1.0%. The incidence of transient hypoparathyroidism was 43.9, 29.0 and 45.5% (A vs B, P = 0.000; A vs C, P = 1.000), and the incidence of permanent hypoparathyroidism was 1.0, 0.7 and 4.5% (P > 0.05). The recovery rates of serum parathyroid hormone levels were 71.4, 72.2 and 66.0% at 6-month follow-up (P > 0.05).ConclusionAutotransplantation of a parathyroid gland does not affect the incidence of permanent hypoparathyroidism, but increases the risk of transient hypoparathyroidism when the rest of parathyroid glands are preserved in situ. At least 2 parathyroid glands should be preserved during total thyroidectomy with central neck dissection to prevent permanent hypoparathyroidism.

Protocol for management after thyroidectomy: a retrospective study based on one-center experience.

Background and aimThe optimal approach to detect and treat symptomatic hypocalcemia (SxH) after thyroidectomy is still uncertain. In our retrospective study, we sought to set a standardized postoperative management protocol on the basis of relative change of parathyroid hormone (PTH) and absolute value of postoperative day 1 (POD1) PTH.MethodsPatients who underwent thyroidectomy were identified retrospectively in our prospective database. Blood was collected 1 day before surgery and on POD1. Extra calcium and calcitriol supplement was prescribed when necessary. Meanwhile, postoperative signs of SxH were treated and recorded in detail. Patients were followed up for 1 month after surgery and then 3 months thereafter.ResultsA total of 744 patients were included in the final analysis. Transient SxH occurred in 86 (11.6%) patients, and persistent SxH occurred in 4 (0.54%) patients in more than half year after surgery. Relative decrease of PTH reached its maximal discriminative effect at 70% (area under the curve [AUC] =0.754), with a sensitivity of 72.1% and a specificity of 75%. In Group 1 (≤70%), 24 (4.67%) patients were interpreted as having SxH, whereas in Group 2, 62 (27.0%) patients had SxH (>70%), P<0.001. Days of symptom relief in Group 1–1 (1, 2) were significantly shorter than those in Group 2–2 (1, 10), P=0.023. In Group 2, 112 (80%) patients with POD1 PTH <1 pmol/L were treated with calcitriol, whereas only 8 (8.89%) patients with POD1 PTH ≥1 pmol/L were treated with calcitriol (P<0.001). According to relief of SxH and recovery of parathyroid function, treating with and without calcitriol showed no difference in patients with POD1 PTH <1 and ≥1 pmol/L.ConclusionRelative decrease of PTH >70% is a significant risk factor for SxH in post-thyroidectomy. The decreasing percent of PTH ≤70% ensures discharge on POD1, but longer hospitalization was advocated for patients with decreasing percent of PTH >70%, who needed extra calcitriol supplement when POD1 PTH <1 pmol/L.

Surgical procedures for papillary thyroid carcinoma located in the thyroid isthmus: an intention-to-treat analysis.

ObjectiveWe sought to evaluate and compare the outcomes of different surgical protocols for papillary thyroid cancer (PTC) located in the isthmus in a retrospective intention-to-treat analysis.Patients and methodsThe data of 3,068 patients who received thyroidectomy due to thyroid cancer in our center were reviewed. Of these, 103 patients had a dominant carcinoma located in the isthmus. Various baseline and tumor characteristics and surgical outcomes were evaluated and compared with respect to the different surgical protocols (85 cases with total thyroidectomy and 18 cases with less-than-total thyroidectomy). Univariate and multivariate analyses were performed to identify resected patients who developed recurrence with isthmic PTC.ResultsThe postoperative complication rates were comparable between the two groups (17.6% versus 11.1%, P=0.500). Although the total thyroidectomy group showed a much higher rate (P=0.004) and number (P<0.001) of parathyroidectomies, long-term follow-up indicated that parathyroid autotransplantation did not significantly damage the function of the parathyroid (P>0.05). Tumor recurrence was observed in five patients, including two patients in the total thyroidectomy group and three patients in the less-than-total thyroidectomy group; the tumor recurrence rate in the total thyroidectomy group was significantly lower than that in the less-than-total thyroidectomy group (P=0.040). Univariate and multivariate analyses indicated less-than-total thyroidectomy as a risk factor for tumor recurrence in PTC cases with tumors located at the isthmus (hazard ratio: 1.870, 95% confidence interval: 1.320–2.218, P<0.001).ConclusionOur findings indicate that total thyroidectomy is an appropriate initial surgical protocol for isthmic PTC due to the lower recurrence rate, comparable postoperative complication rate, and parathyroid function recovery.

Recovery of parathyroid function after total thyroidectomy

Recovery of parathyroid function after total thyroidectomy

Recovery of Parathyroid Hormone Secretion and Function in Postoperative Hypoparathyroidism: A Case Series

Transient and permanent postoperative hypoparathyroidism are recognized complications of neck surgery. Postoperative hypoparathyroidism is usually considered permanent when it persists for 6 months; in rare cases, recovery of hypoparathyroidism through 1 year has been described. Recovery of hypoparathyroidism years after diagnosis has not previously been reported. We report four patients being treated with PTH(1-84) in a research protocol who recovered from postoperative hypoparathyroidism many years after onset. Recovery from hypoparathyroidism was established by: 1) serum calcium and PTH levels within the normal range off PTH(1-84) treatment for at least 1 week; 2) requirement for daily calcium supplementation reduced to ≤1 g; and 3) no supplemental active vitamin D therapy. Hypoparathyroidism developed in three subjects after repeated neck surgery for primary hyperparathyroidism and in one subject after total thyroidectomy for Graves' disease. Parathyroid tissue autotransplant was performed in two of the four subjects. Two had undetectable PTH levels at study entry, whereas the other two subjects had detectable, although low, PTH levels. Hypoparathyroidism had been present for at least 8 years, and in one case for 16 years. The recovery of parathyroid function followed treatment with PTH(1-84) for 36 to 63 months. Although it remains relatively rare, this report documents recovery of long-term postoperative hypoparathyroidism many years after the initial diagnosis. A potential role for exogenous PTH is intriguing with several plausible mechanisms.

Simultaneous Kidney-Parathyroid Allotransplantation From a Single Donor After 20 Years of Tetany: A Case Report

Persistent hypocalcemia after total parathyroidectomy and autotransplantation is rare and occasionally has been treated using allotransplantation of parathyroid tissue. We present the case of a 32-year-old woman with terminal renal failure who at age 5 years underwent a first renal transplantation from a brain-dead donor. The graft was lost as a result of acute rejection. Tertiary hypoparathyroidism developed, which was treated with total parathyroidectomy and implantation in the forearm of a standardized amount of parathyroid tissue. The graft failed, and hypoparathyroidism developed. Despite a second implantation of cryopreserved autologous tissue, severe hypocalcemia persisted with a tendency for tetany. Although the patient was highly dependent on high-dose vitamin D 3 (tacalcitol) and calcium supplements, regular paresthesias and tetany developed. At age 9 years, the patient underwent a second renal transplant from a living related donor (her mother). After 18 years, the graft was lost as a result of chronic cyclosporine toxicity and angiosclerosis. Four years later, the patient underwent combined kidney and parathyroid transplantation from a local brain-dead donor. Preservation of the parathyroid glands was in University of Wisconsin solution, with cold ischemia time of 14 hours. Directly after the renal transplantation, parathyroid transplantation was performed, with implantation in the forearm of the total amount of donor parathyroid tissue. Postoperatively, there was recovery of parathyroid function, and the patient was able to discontinue vitamin D and calcium supplements after more than 20 years.

Fibroblast Growth Factor-23 (FGF23) in Patients with Transient Hypoparathyroidism: Its Important Role in Serum Phosphate Regulation

Hypoparathyroidism is a complication of thyroidectomy that causes hyperphosphatemia primarily due to enhanced reabsorption of phosphate in the kidney resulting from decreased parathyroid hormone (PTH) secretion. Fibroblast growth factor-23 (FGF23) is a hormone-like factor that is thought to play an important role in phosphate homeostasis. However, the changes and role of FGF23 in transient hypoparathyroidism after thyroidectomy are not clear. We examined changes in serum levels of calcium, phosphate, intact PTH, 1,25-dihydroxyvitamin D, and FGF23 in 12 patients (10 women, 2 men; mean age, 51 yr) who developed transient hypoparathyroidism after thyroidectomy. Serum phosphate reached its peak level (5.9 +/- 0.5 mg/dl) approximately 4 days after development of hypoparathyroidism, and this was followed by a peak in the serum FGF23 level (71 +/- 28 ng/l). Serum levels of calcium, phosphate, and FGF23 normalized after recovery of parathyroid function. There was a significant positive correlation between serum phosphate and FGF23 levels (P<0.05). Serum FGF23 was elevated in patients with hypoparathyroidism and hyperphosphatemia and normalized along with normalized phosphate levels after recovery of parathyroid function. The peak level of phosphate always preceded that of FGF23 by several days, suggesting that elevated phosphate is a primary stimulus for release of FGF23. This homeostatic regulation of phosphate differs considerably from that of serum calcium whose change is rapidly corrected within minutes.

Fibroblast growth factor (FGF)-23 in patients with hypoparathyroidism

Hypoparathyroidism is a well-described cause of hyperphosphatemia. We aimed to clarify the physiological role of FGF-23 in serum phosphate homeostasis in hypoparathyroidism after thyroidectomy. Increased serum FGF-23 levels were found in patients with hyperphosphatemia and hypocalcemia, caused by hypoparathyroidism after thyroidectomy. After the recovery of parathyroid function, the serum level of calcium, phosphate, and FGF-23 was normalized. Serum FGF-23 levels were significantly higher in patients with permanent hypoparathyroidism than in healthy controls. These results indicate that FGF-23 may play an important role in serum phosphate homeostasis by its up-regulation in the hyperphosphatemic condition.

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

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. 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. 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. 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.

Recovery of parathyroid function after total thyroidectomy.

To prevent postoperative hypoparathyroidism following total thyroidectomy, the parathyroid glands are preserved in situ and/or resected or devascularized parathyroid glands are autotransplanted. We conducted a retrospective investigation utilizing biochemical and specific endocrine assessments to evaluate the difference in recovery of parathyroid function between the two operative methods. A total of 92 patients underwent total thyroidectomy at our hospital during the period between 1990 and 1997. These patients were divided into a preservation group (n = 83), with one or more preserved glands in situ, and an autotransplantation group (n = 9), with only transplanted glands. The level of intact parathyroid hormone (PTH) was completely restored by 1 year postoperatively in 83% (69/83) of the preservation group patients. In the remaining 14 patients (17%), the intact PTH had fallen below detectable levels on postoperative day (POD) 1, then subsequently recovered to 70% of the preoperative levels. Comparatively, in the autotransplantation group, the mean level of intact PTH recovered to only 43% of the preoperative levels. The results of this study suggest that parathyroid glands should be preserved in situ whenever possible, and that when intact PTH levels fall below detectable limits on POD 1, they may never recover to the preoperative levels in those patients.