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Original Article |

Predictive Value of Age and Serum Parathormone and Vitamin D3 Levels for Postoperative Hypocalcemia After Total Thyroidectomy for Nontoxic Multinodular Goiter FREE

Yeşim Erbil, MD; Alp Bozbora, MD; Neşe Özbey, MD; Halim İşsever, PhD; Feríhan Aral, MD; Selçuk Özarmağan, MD; Serdar Tezelman, MD
[+] Author Affiliations

Author Affiliations: Departments of General Surgery (Drs Erbil, Bozbora, [[Ouml]]zarma[[gbreve]]an, and Tezelman), Endocrinology (Drs [[Ouml]]zbey and Aral), and Public Health (Dr [[Idot]][[scedil]]sever), Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.


Arch Surg. 2007;142(12):1182-1187. doi:10.1001/archsurg.142.12.1182.
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Published online

Hypothesis  Age, postoperative serum parathormone (PTH) level, and preoperative serum 25-hydroxyvitamin D3 (25-OHD) level predict postoperative hypocalcemia after total thyroidectomy.

Design  Prospective clinical trial.

Setting  Tertiary referral center.

Patients  One hundred thirty patients with nontoxic multinodular goiter. Patients were divided into 2 groups according to the postoperative serum calcium level. Group 1 (n = 32) consisted of patients with a postoperative serum calcium level of 8 mg/dL or less, and group 2 (n = 98) consisted of patients with a postoperative serum calcium level higher than 8 mg/dL.

Interventions  The preoperative serum 25-OHD level and preoperative and postoperative serum calcium and PTH levels were determined.

Main Outcome Measures  The number of patients developing hypocalcemia and prediction of postoperative hypocalcemia by the serum 25-OHD and PTH levels.

Results  Hypocalcemia developed in 32 patients (24.6%) (group 1). The preoperative serum 25-OHD level and postoperative serum calcium and PTH levels in group 1 were significantly lower than in group 2 (P = .001). With logistic regression analysis, factors that were predictive of postoperative hypocalcemia included a preoperative serum 25-OHD level less than 15 ng/mL (P < .001; odds ratio, 558.5), a postoperative serum PTH level less than 10 pg/mL (P = .01; odds ratio, 16.4), and being older than 50 years (P = .01; odds ratio, 4.6).

Conclusions  Age, a low preoperative serum 25-OHD level, and a low postoperative serum PTH level are significantly associated with postoperative hypocalcemia. The low preoperative serum 25-OHD level was more significant than the low postoperative serum PTH level in the prediction of postoperative hypocalcemia.

Thyroidectomy is one of the most frequent operations performed for patients with nontoxic multinodular goiter. The goals of surgical treatment in thyroid disease should be to eliminate the disease with low complication rates and to minimize reoperation for incidental thyroid carcinoma in multinodular goiter.15 In recent years, total thyroidectomy (TT) and near-total thyroidectomy have emerged as surgical options in the surgical treatment of patients with nontoxic multinodular goiter, especially in endemic iodine-deficient regions.610 Transient hypocalcemia is the most frequent complication after TT and continues to challenge even the experienced surgeon.1115 The etiology of hypoparathyroidism seems to be a multifactorial phenomenon, but the most important factors are the iatrogenic surgical trauma to parathyroid glands, the extent of surgery, the experience of the surgeon, and the number of functioning glands left behind. Among the potential factors causing this, a decrease of serum calcium in hungry bone syndrome is implicated in patients with hyperthyroidism. The postoperative reversal of osteodystrophy and the deposition of calcium in bones may also contribute to a decreased serum calcium level.1114

Vitamin D3 has a critical role in calcium homeostasis. After it is acquired by either sunshine or diet, it is converted to 25-hydroxyvitamin D3 (25-OHD) in the liver. Serum 25-OHD is supposedly biologically inactive. However, it is the most reliable parameter reflecting the vitamin D3 status of the body. Serum 25-OHD is hydroxylated in the kidney to 1,25-dihydroxyvitamin D3 (calcitriol), which is the active metabolite of vitamin D3 that binds to a nuclear receptor. Interaction with genomic DNA reveals the biological effects of vitamin D3, ie, increased intestinal calcium and phosphate absorption, decreased parathormone (PTH) secretion, and increased osteoclastic differentiation. 1α-Hydroxylation and production of active vitamin D3 in the kidney are stimulated by increased PTH concentrations.1618

Recently, several investigators1922 have suggested that intraoperative or postoperative serum PTH levels are early predictors of the development of postoperative hypocalcemia after TT. The aims of this prospective clinical study are the following: (1) to evaluate the accuracy of age and postoperative serum PTH levels to predict patients at risk for postoperative hypocalcemia; and (2) to suggest that the preoperative serum vitamin D3 level might predict the development of hypocalcemia after total thyroidectomy. To our knowledge, this is the first prospective study performed to detect the value of the serum 25-OHD level to predict postoperative hypocalcemia after TT.

PATIENTS

In the Department of Surgery, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey, 130 consecutive patients with nontoxic multinodular goiter treated by bilateral TT from January 1, 2005, to December 1, 2005, were included prospectively in this study. Patients having hyperthyroidism, substernal goiter or a previous thyroid or neck operation, and concomitant parathyroid disease were excluded. No patients underwent bone mineral density measurement. However, no patients had signs or symptoms indicating metabolic bone disease or were receiving medications known to affect serum calcium metabolism such as oral calcium and vitamin D supplementation, antiresorptive agents, hormone replacement therapy for postmenopausal women, anabolic agents, thiazide-type diuretics, and antiepileptic agents. The study plan was reviewed and approved by our institutional ethical committee, and informed consent was obtained from all of the patients.

Serum calcium, PTH, 25-OHD, alkaline phosphatase, creatinine, and albumin levels were determined the day before surgery. Serum PTH and calcium levels were measured 12 hours postoperatively, and measurements of serum calcium levels were repeated 24 hours postoperatively. The lowest postoperative serum calcium level was determined for all of the patients. The serum calcium concentration was adjusted for serum albumin concentration. The main indications for surgery were large goiter with compressive effect to all of the patients. Total thyroidectomy was performed by experienced endocrine surgeons (Y.E., A.B., S.O., and S.T.) and is defined as total bilateral extracapsular thyroidectomy. Recurrent laryngeal nerves were carefully identified and dissected. We attempted to identify all parathyroid glands and preserve them with meticulous dissection for their blood supply. For this reason, all of the vessels were ligated close to the thyroid gland, especially the branches of the inferior thyroid artery. Where we could not identify lower parathyroid glands, we did not dissect the thymus or the thyrothymic ligament to find unexposed glands. No biopsies were taken from parathyroids. There were no patients with damaged parathyroid glands autotransplanted into the sternocleidomastoid muscle. Signs of ischemia of parathyroid glands were not observed during the operations. In the histopathologic examination of the resected thyroid tissue, parathyroid tissue was not identified.

One hundred thirty patients were divided into 2 groups according to the postoperative calcium level. Patients in group 1 (n = 32) had a postoperative serum calcium level of 8 mg/dL or less, whereas patients in group 2 (n = 98) had a serum calcium level higher than 8 mg/dL (to convert milligrams per deciliter to millimoles per liter, multiply by 0.25). Hypocalcemia was defined as a serum calcium concentration of 8 mg/dL or less. Asymptomatic hypocalcemia was a laboratory finding, whereas symptomatic hypocalcemia had clinical symptoms besides laboratory findings. The presence of clinical symptoms or signs of hypocalcemia were reported, and they included facial paresthesia, positive Chvostek or Trousseau signs, and muscular spasm. The serum calcium level of patients with hypocalcemia was measured every 12 hours until the serum calcium level stabilized. All of the patients who developed asymptomatic hypocalcemia were treated with oral calcium (3-6 g/d). Symptomatic hypocalcemia was treated with parenteral calcium and an oral calcitriol supplementation of 1.0 to 1.5 μg/d. Those patients with asymptomatic hypocalcemia were discharged with oral calcium, whereas patients with symptomatic hypocalcemia were discharged with oral calcium and/or calcitriol at doses modified in relation to the serum calcium concentration and were followed up weekly until their serum calcium and PTH levels normalized.

BIOCHEMICAL ANALYSIS

Serum calcium, alkaline phosphatase, creatinine, and albumin levels were determined by an autoanalyzer (Cobas Integra 800; Roche Diagnostics, Basel, Switzerland). Serum 25-OHD and PTH levels were determined by immunoradiometric assay using commercially available kits—the PTH 120-minute immunoradiometric assay kit and the 25-OHD radioimmunoassay kit, respectively (BioSource Europe SA, Nivelles, Belgium). Reference ranges of biochemical parameters were as follows: 8.5 to 10.5 mg/dL for serum calcium; 90 to 260 U/L for serum alkaline phosphatase (to convert units per liter to microkatals per liter, multiply by 0.0167); 0.6 to 1.5 mg/dL for serum creatinine (to convert milligrams per deciliter to micromoles per liter, multiply by 88.4); 3.5 to 5.0 g/dL for serum albumin (to convert grams per deciliter to grams per liter, multiply by 10); 6 to 46 ng/mL for serum 25-OHD (to convert nanograms per milliliter to nanomoles per liter, multiply by 2.496); and 10 to 65 pg/mL for serum PTH (to convert picograms per milliliter to nanograms per liter, multiply by 0.1053).

STATISTICAL ANALYSIS

Data were analyzed using SPSS version 11.0 statistical software for Windows (SPSS, Inc, Chicago, Illinois). Results were expressed as mean (standard deviation). Comparisons of data were done by Wilcoxon signed rank test, χ2 test, and logistic regression analysis. Results were considered statistically significant at P < .05 (2-tailed).

The mean (SD) age was 48.2 (11.5) years (range, 17-67 years) for 130 patients. The female to male ratio was 7.6:1 (n = 115 and 15, respectively). The mean (SD) preoperative levels of serum albumin, creatinine, calcium, PTH, alkaline phosphatase, and 25-OHD were 3.8 (0.6) g/dL, 0.8 (0.2) mg/dL, 8.7 (0.3) mg/dL, 38.3 (8.4) pg/mL, 174.6 (88.7) U/L, and 18.2 (14.3) ng/mL, respectively. The mean (SD) postoperative serum calcium and PTH levels were 8.3 (0.8) mg/dL and 31.4 (15.6) pg/mL, respectively. Postoperative serum calcium and PTH levels were lower than preoperative serum calcium and PTH levels (both P = .001) (Table 1).

Table Graphic Jump LocationTable 1. Demographic and Biochemical Parameters of the Patientsa

There was no operative mortality. The incidence of transient vocal cord paralysis was 5.3% (7 of 130 patients). Persistent vocal cord paralysis and hypoparathyroidism were not encountered in our series. In the histopathologic evaluation, papillary thyroid cancer was detected in 15 patients (11.5%), of whom 13 (86.6%) had papillary microcarcinoma (≤ 1 cm). The mean (SD) size of the tumor was 4.6 (3.3) mm (range, 2-13 mm). Four patients had thyroid capsule invasion and 3 patients had vascular invasion. Papillary thyroid carcinoma was multifocal in 3 patients. Those patients with papillary thyroid carcinoma were classified as a low-risk group.

POSTOPERATIVE HYPOCALCEMIA

In 32 of 130 patients (24.6%) (ie, group 1), the serum calcium level was found to be less than 8 mg/dL at 12 and 24 hours postoperatively. These patients were noted to have a serum PTH level less than 15 pg/mL (mean [SD], 6.5 [1.6] pg/mL) at 12 hours postoperatively.

Age and the serum alkaline phosphatase level were significantly higher in group 1 when compared with group 2 (P = .001). There were no significant differences between the preoperative serum albumin, creatinine, calcium, and PTH levels of groups 1 and 2 (P > .05). The preoperative serum 25-OHD level and postoperative serum calcium and PTH levels were significantly lower in group 1 than in group 2 (P = .001) (Table 2).

Table Graphic Jump LocationTable 2. A Comparison of Laboratory Features in Patients With Hypocalcemia and Patients With Normocalcemia

Of 32 patients, 22 (68.8%) developed symptomatic hypocalcemia and 10 (31.2%) developed asymptomatic hypocalcemia. The preoperative serum 25-OHD level of the patients with symptomatic hypocalcemia (mean [SD], 5.6 [1.2] ng/mL) was significantly lower than that of patients with asymptomatic hypocalcemia (mean [SD], 16.2 [6.3] ng/mL) (P = .005). Hospital stay was significantly longer in group 1 (mean [SD], 3.6 [1.1] days; range, 2-6 days) compared with group 2 (mean [SD], 1.3 [0.4] days; range, 1-2 days) (P = .001). In addition, hospital stay was significantly longer in the patients with symptomatic hypocalcemia (mean [SD], 4.1 [1.2] days; range, 3-6 days) compared with the patients with asymptomatic hypocalcemia (mean [SD], 2.6 [0.5] days; range, 2-3 days) (P = .004).

The results of the logistic regression analysis for postoperative hypocalcemia are shown in Table 3. Age, postoperative serum PTH level, and preoperative serum 25-OHD level were independent significant variables of the development of hypocalcemia after TT. Patients older than 50 years had a 4.6-fold increased risk of postoperative hypocalcemia (odds ratio, 4.6; 95% confidence interval, 1.3-15.8), patients with a postoperative serum PTH level less than 10 pg/mL had a 16.4-fold increased risk for postoperative hypocalcemia (odds ratio, 16.4; 95% confidence interval, 1.8-143.8), and patients with a preoperative serum 25-OHD level less than 15 ng/mL had a 558.5-fold increased risk for postoperative hypocalcemia (odds ratio, 558.5; 95% confidence interval, 27.6-11 291.9).

Table Graphic Jump LocationTable 3. Logistic Linear Regression Analysis Between Dependent and Independent Parameters

Preoperatively, the serum 25-OHD level was 15 ng/mL or less in 77 patients and higher than 15 ng/mL in 53 patients. Postoperative serum calcium and PTH levels in patients with a serum 25-OHD level of 15 ng/mL or less (mean [SD], 8.2 [0.9] mg/dL and 28.3 [16.2] pg/dL, respectively) were significantly lower than in patients with a serum 25-OHD level higher than 15 ng/mL (mean [SD], 8.5 [0.5] mg/dL and 34.6 [13.2] pg/dL, respectively) (P < .01). Of the 77 patients with a serum 25-OHD level of 15 ng/mL or less, 24 (31.2%) developed postoperative hypocalcemia; of the 53 patients with a serum 25-OHD level higher than 15 ng/mL, 8 (15.1%) developed postoperative hypocalcemia. The ratio of postoperative hypocalcemia was significantly higher in the patients with a serum 25-OHD level of 15 ng/mL or less than in the patients with a serum 25-OHD level higher than 15 ng/mL (P < .03). The ratio of symptomatic hypocalcemia was significantly higher in the patients with a serum 25-OHD level of 15 ng/mL or less than in the patients with a serum 25-OHD level higher than 15 ng/mL (83.0% vs 25.0%, respectively; P < .03).

Preoperatively, the serum 25-OHD level was 25 ng/mL or less in 97 patients and higher than 25 ng/mL in 33 patients. Of the 97 patients with a serum 25-OHD level of 25 ng/mL or less, 31 (32.0%) developed postoperative hypocalcemia; of the 33 patients with a serum 25-OHD level higher than 25 ng/mL, 1 (3.0%) developed postoperative hypocalcemia. The ratio of postoperative hypocalcemia was significantly higher in the patients with a serum 25-OHD level of 25 ng/mL or less than in the patients with a serum 25-OHD level higher than 25 ng/mL (P < .001).

According to the cutoff of 25 ng/mL for the preoperative serum 25-OHD level, logistic regression analysis for postoperative hypocalcemia was performed. The preoperative serum 25-OHD level was the only independent significant variable of postoperative hypocalcemia (P = .001), whereas age and the postoperative serum PTH level were not significant variables of postoperative hypocalcemia (P = .63 and P = .12, respectively). Patients with a preoperative serum 25-OHD level of 25 ng/mL or less had a 15-fold increased risk for postoperative hypocalcemia (odds ratio, 15.4; 95% confidence interval, 2.0-115.9; P = .009).

FOLLOW-UP

Ten of 32 patients with asymptomatic hypocalcemia were treated only with oral calcium supplementation. Twenty-two patients with symptomatic hypocalcemia were treated with parenteral calcium as well as oral vitamin D3 and calcium supplementation until they were discharged. Symptomatic patients (n = 22) were treated with parenteral calcium and calcitriol supplementation. Treatment was discontinued at the first week in 10 patients with asymptomatic hypocalcemia. In patients with symptomatic hypocalcemia, treatment was discontinued at the second week in 4 patients, at the third week in 6 patients, at the fourth week in 8 patients, and at the fifth week in 4 patients. Treatment in all of the patients with symptomatic hypocalcemia could not be stopped in the first week. However, treatment was discontinued at the first week in all of the patients with asymptomatic hypocalcemia.

We investigated the prediction of developing postoperative hypocalcemia by age, preoperative serum 25-OHD level, and postoperative serum PTH level after TT and found that age, a low preoperative serum 25-OHD level, and a low postoperative serum PTH level were significantly associated with postoperative hypocalcemia. The predictive value of a low preoperative serum 25-OHD level was significantly higher than that of a low postoperative serum PTH level (P < .001). Preoperative serum 25-OHD and postoperative serum PTH levels in the patients with hypocalcemia were significantly lower than in the patients with normocalcemia. Age and the serum alkaline phosphatase level in the patients with hypocalcemia were significantly higher than in the patients with normocalcemia (P < .001). According to logistic regression analysis, a preoperative serum 25-OHD level less than 15 ng/mL, a postoperative serum PTH level less than 10 pg/mL, and being older than 50 years were significantly predictive factors for postoperative hypocalcemia.

Although the morbidity of thyroid surgery has decreased during the past century, hypoparathyroidism continues to occur. Postoperative hypocalcemia is one of the most frequent complications after TT. In several studies,13,2329 the incidence of hypoparathyroidism varied from 1.6% to higher than 50%. Even when experienced surgeons believe that the parathyroid glands were preserved and reliable during the operation, hypocalcemia may occur.13,23,24 The causes of hypocalcemia after TT are multifactorial, and some of the factors involve iatrogenic surgical trauma to parathyroid glands, inadvertent removal of parathyroid glands, the number of functioning glands left behind, the extent of surgery, the experience of the surgeon, hyperthyroidism, retrosternal goiter, concomitant neck dissection, and thyroid carcinoma.1115,2934 The risk of hypoparathyroidism after thyroid operation for Graves disease is 20 times higher than in nontoxic multinodular goiter.35,36 In patients with substernal goiter, parathyroid glands might be removed inadvertently.37,38 During thyroid reoperation, fibrosis causes difficult visualization of parathyroid glands and is associated with a higher risk of postoperative hypocalcemia.31,32 Therefore, patients having hyperthyroidism, substernal goiter or a previous thyroid or neck operation, and concomitant parathyroid disease were excluded in our study. The symptoms of hypocalcemia usually manifest 24 to 48 hours after the thyroid operations. Monitoring of the postoperative serum calcium concentration is necessary to detect patients who develop hypocalcemia and need supplementation therapy. Some investigators14,39,40 follow a strict protocol including frequent measurement of serum calcium levels for several days. There is no consensus about the optimal postoperative time to determine the serum calcium level.39,40 Recently, there has been a great deal of interest in identifying perioperative factors that could predict the development of hypocalcemia after thyroidectomy. Intraoperative or postoperative serum PTH measurements have been demonstrated to be useful in the identification of patients who are at risk for hypocalcemia.1619 In addition to its clinical usefulness in the identification of patients who should be treated, a serum PTH assay may also be cost-effective by reducing the postoperative length of hospital stay and the need for expensive postoperative serum calcium monitoring.4143 The accuracy of a low intraoperative serum PTH level to predict biochemical and symptomatic postoperative hypocalcemia was effective.1619 The sensitivity of the intraoperative serum PTH level to predict postoperative hypocalcemia is 70% to 80%.16,4143 In recent studies,16,19 low serum PTH levels 8 and 12 hours after operation were the most accurate (98%) predictors of postoperative hypocalcemia. Patients treated by TT and having a serum PTH level greater than 15 pg/mL at 8 hours postoperatively were at extremely low risk for developing postoperative hypocalcemia.41,42 In our study, serum calcium and PTH levels were determined the day before operation and serum PTH and calcium levels were measured 12 hours after TT. All of the patients who developed hypocalcemia were noted to have a serum PTH level less than 15 pg/mL at 12 hours postoperatively.

Symptomatic hypocalcemia usually contributes to the length of hospital stay. Some investigators4144 empirically propose routine oral calcium and/or calcitriol administration in patients undergoing TT to increase early hospital discharge. In our study, the hospitalization period was longer for patients with hypocalcemia than for patients with normocalcemia. In previous studies,1619,4143 only intraoperative and postoperative serum PTH levels were used to predict postoperative hypocalcemia. To our knowledge, ours is the first prospective study performed to detect the strong value of the serum 25-OHD level in predicting postoperative hypocalcemia after TT. Chia et al45 demonstrated that preoperative levels of serum 25-OHD did not correlate with postoperative serum calcium levels and were not a useful predictor of postoperative hypocalcemia. However, their patient population included those with thyroid disorders, parathyroid adenoma, and parathyroid hyperplasia and they performed different surgical procedures. We believe that the nonpredictive result associated with the serum 25-OHD level might be related to these factors in their study.

Previous studies4648 indicated that vitamin D deficiency increased in elderly people, even among healthy, ambulatory elderly people. Advanced age is reported to be a major risk factor for vitamin D deficiency.16 Aging is associated with alterations in vitamin D metabolism: age-related decline in cutaneous accumulation of 7-dehydrocholesterol (which is converted into previtamin D3 by solar UV radiation),17 a decrease in renal 1α-hydroxylase activity,49 and decreased intestinal calcium absorption.50 These factors and poorer nutritional intake may be responsible for the increased risk of vitamin D deficiency during aging. Therefore, aging is associated with a decrease in defense mechanisms against hypocalcemia. Being older than 50 years was associated with an increased risk of postoperative hypocalcemia in our patients who underwent TT. Insufficiency in calcium absorption due to low vitamin D concentration leads to an increase in PTH secretion. An increased PTH concentration stimulates the synthesis of calcitriol, thereby improving calcium absorption efficiency. In our patients recovering from TT, a compensatory increase in PTH may not be achieved transiently; therefore, hypocalcemia develops in these patients more readily. A deficiency in normal homeostatic mechanisms against hypocalcemia during aging may further exaggerate the decrease in serum calcium concentrations.

Vitamin D deficiency has been frequently documented in medically ill and free-living populations.16 In Turkey, more than 30% of different groups of subjects have vitamin D deficiency.48,51 There is currently no consensus on which level of serum 25-OHD is the optimal concentration. While a 25-OHD concentration less than 30 nmol/L has been suggested by some52 to represent vitamin D deficiency, others have suggested that concentrations of less than 37.5 nmol/L,53 40 nmol/L,54 62 nmol/L,55 or even 120 nmol/L56 are deleterious to bone. In our study, serum 25-OHD levels less than 15 ng/mL (37.5 nmol/L) were accepted to indicate vitamin D deficiency.

Logistic regression analysis for postoperative hypocalcemia was performed according to the cutoff value of 25 ng/mL for the preoperative serum 25-OHD level. The preoperative serum 25-OHD level was the only independent significant variable for postoperative hypocalcemia. A preoperative serum 25-OHD level less than 25 ng/mL indicated a 15-fold increased risk of postoperative hypocalcemia. We believe that patients with a preoperative serum vitamin D level less than 25 ng/mL can compensate for postoperative hypocalcemia due to parathyroid injury without clinical and laboratory findings of hypocalcemia.

A high frequency of vitamin D deficiency could be responsible for the relatively high frequency of temporary postoperative hypocalcemia in our study. In populations with a higher incidence of vitamin D deficiency, the preoperative serum 25-OHD level plays a major role in predicting postoperative symptomatic and/or biochemical transient hypocalcemia in patients who have undergone thyroidectomy for benign conditions. The effects of preoperative supplemental doses of vitamin D on the frequency of post-thyroidectomy transient hypocalcemia should be clarified by further prospective studies.

In conclusion, age, the serum PTH level, and the serum 25-OHD level are predictive factors for hypocalcemia after TT. The preoperative serum 25-OHD level is strongly useful to predict hypocalcemia after thyroidectomy. Patients with a preoperative serum 25-OHD level less than 15 ng/mL should receive calcium or vitamin D supplementation after TT to avoid symptomatic hypocalcemia and to decrease the length of hospital stay.

Correspondence: Serdar Tezelman, MD, Department of General Surgery, Istanbul Faculty of Medicine, Istanbul University, Istanbul 34093, Turkey (stezelman@superonline.com).

Accepted for Publication: June 27, 2006.

Author Contributions:Study concept and design: Erbil, Özarmağan, and Tezelman. Acquisition of data: Erbil. Analysis and interpretation of data: Erbil, Bozbora, Özbey, İşsever, Aral, and Tezelman. Drafting of the manuscript: Erbil, Bozbora, İşsever, Aral, ÖOzarmağan, and Tezelman. Critical revision of the manuscript for important intellectual content: Özbey and Tezelman. Statistical analysis: Erbil and İşsever. Study supervision: Tezelman.

Financial Disclosure: None reported.

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Reeve  TThompson  NW Complications of thyroid surgery: how to avoid them, how to manage them, and observations on their possible effect on the whole patient. World J Surg 2000;24 (8) 971- 975
PubMed Link to Article
Rosato  LAvenia  NBernante  P  et al.  Complications of thyroid surgery: analysis of a multicentric study on 14 934 patients operated on in Italy over 5 years. World J Surg 2004;28 (3) 271- 276
PubMed Link to Article
Gonçalves Filho  JKowalski  LP Surgical complications after thyroid surgery performed in a cancer hospital. Otolaryngol Head Neck Surg 2005;132 (3) 490- 494
PubMed Link to Article
Reeve  TSDelbridge  LBrady  PCrummer  PSmyth  C Secondary thyroidectomy: a twenty-year experience. World J Surg 1988;12 (4) 449- 453
PubMed Link to Article
Chao  TCJeng  LBLin  JDChen  MF Reoperative thyroid surgery. World J Surg 1997;21 (6) 644- 647
PubMed Link to Article
Pereira  JAJimeno  JMiquel  J  et al.  Nodal yield, morbidity, and recurrence after central neck dissection for papillary thyroid carcinoma. Surgery 2005;138 (6) 1095- 1100
PubMed Link to Article
Zarnegar  RBrunaud  LClark  OH Prevention, evaluation, and management of complications following thyroidectomy for thyroid carcinoma. Endocrinol Metab Clin North Am 2003;32 (2) 483- 502
PubMed Link to Article
Yamashita  HMurakami  TNoguchi  S  et al.  Postoperative tetany in Graves disease: important role of vitamin D metabolites. Ann Surg 1999;229 (2) 237- 245
PubMed Link to Article
Moriyama  TYamashita  HNoguchi  S  et al.  Intraoperative parathyroid hormone assay in patients with Graves' disease for prediction of postoperative tetany. World J Surg 2005;29 (10) 1282- 1287
PubMed Link to Article
Shaha  ARJaffe  BM Parathyroid preservation during thyroid surgery. Am J Otolaryngol 1998;19 (2) 113- 117
PubMed Link to Article
Singh  BLucente  FEShaha  AR Substernal goiter: a clinical review. Am J Otolaryngol 1994;15 (6) 409- 416
PubMed Link to Article
Güllüoğlu  BMManukyan  MNCingi  A  et al.  Early prediction of normocalcemia after thyroid surgery. World J Surg 2005;29 (10) 1288- 1293
PubMed Link to Article
Tartaglia  FGiuliani  ASgueglia  M  et al.  Randomized study on oral administration of calcitriol to prevent symptomatic hypocalcemia after total thyroidectomy. Am J Surg 2005;190 (3) 424- 429
PubMed Link to Article
Bellantone  RLombardi  CPRaffaelli  M  et al.  Is routine supplementation therapy (calcium and vitamin D) useful after total thyroidectomy? Surgery 2002;132 (6) 1109- 1112
PubMed Link to Article
Cahill  RAHarty  RCotter  SWatson  RG Parathormone response to thyroid surgery. Am J Surg 2006;191 (4) 453- 459
PubMed Link to Article
McLeod  IKArciero  CNoordzij  JP  et al.  The use of rapid parathyroid hormone assay in predicting postoperative hypocalcemia after total or completion thyroidectomy. Thyroid 2006;16 (3) 259- 265
PubMed Link to Article
Del Rio  PArcuri  MFFerreri  GSommaruga  LSianesi  M The utility of serum PTH assessment 24 hours after total thyroidectomy. Otolaryngol Head Neck Surg 2005;132 (4) 584- 586
PubMed Link to Article
Chia  SHWeisman  RATieu  D  et al.  Prospective study of perioperative factors predicting hypocalcemia after thyroid and parathyroid surgery. Arch Otolaryngol Head Neck Surg 2006;132 (1) 41- 45
PubMed Link to Article
Omdahl  JLGarry  PJHunsaker  LA  et al.  Nutritional status in a healthy elderly population: vitamin D. Am J Clin Nutr 1982;36 (6) 1225- 1233
PubMed
Gloth  FMGundberg  JMHollis  BW  et al.  Vitamin D deficiency in home-bound elderly persons JAMA 1995;274 (21) 1683- 1686
PubMed Link to Article
Atli  TGullu  SUysal  AR  et al.  The prevalence of vitamin D deficiency and effects of ultraviolet light on vitamin D levels in elderly Turkish population. Arch Gerontol Geriatr 2005;40 (1) 53- 60
PubMed Link to Article
Friedlander  JJanulis  MTembe  V  et al.  Loss of parathyroid hormone-stimulated 1,25-dihydroxyvitamin D3 production in aging does not involve protein kinase A or C pathways. J Bone Miner Res 1994;9 (3) 339- 345
PubMed Link to Article
Nordin  BECNeed  AGMorris  HAO’Loughlin  PDHorowitz  M Effect of age on calcium absorption in postmenopausal women. Am J Clin Nutr 2004;80 (4) 998- 1002
PubMed
Alagöl  FShihadeh  YBoztepe  H  et al.  Sunlight exposure and vitamin D deficiency in Turkish women. J Endocrinol Invest 2000;23 (3) 173- 177
PubMed Link to Article
LeBoff  MSKohlmeier  LHurwitz  S  et al.  Occult vitamin D deficiency in postmenopausal US women with acute hip fracture. JAMA 1999;281 (16) 1505- 1511
PubMed Link to Article
Webb  ARPilbeam  CHanafin  NHolick  MF An evaluation of the relative contributions of exposure to sunlight and of diet to the circulating concentrations of 25-hydroxyvitamin D in an elderly nursing home population in Boston. Am J Clin Nutr 1990;51 (6) 1075- 1081
PubMed
Need  AGHorowitz  MMorris  HANordin  BC Vitamin D status: effects on parathyroid hormone and 1,25 dihydroxyvitamin D in postmenopausal women. Am J Clin Nutr 2000;71 (6) 1577- 1581
PubMed
Haden  STFuleihan  GEAngel  JECotran  NMLe Boof  MS Calcidiol and PTH levels in women attending an osteoporosis program. Calcif Tissue Int 1999;64 (4) 275- 279
PubMed Link to Article
Kinyamu  HKGallagher  JCRafferty  KABalhorn  KE Dietary calcium and vitamin D intake in elderly women: effect on serum parathyroid hormone and vitamin D metabolites. Am J Clin Nutr 1998;67 (2) 342- 348
PubMed

Figures

Tables

Table Graphic Jump LocationTable 1. Demographic and Biochemical Parameters of the Patientsa
Table Graphic Jump LocationTable 2. A Comparison of Laboratory Features in Patients With Hypocalcemia and Patients With Normocalcemia
Table Graphic Jump LocationTable 3. Logistic Linear Regression Analysis Between Dependent and Independent Parameters

References

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Reeve  TThompson  NW Complications of thyroid surgery: how to avoid them, how to manage them, and observations on their possible effect on the whole patient. World J Surg 2000;24 (8) 971- 975
PubMed Link to Article
Rosato  LAvenia  NBernante  P  et al.  Complications of thyroid surgery: analysis of a multicentric study on 14 934 patients operated on in Italy over 5 years. World J Surg 2004;28 (3) 271- 276
PubMed Link to Article
Gonçalves Filho  JKowalski  LP Surgical complications after thyroid surgery performed in a cancer hospital. Otolaryngol Head Neck Surg 2005;132 (3) 490- 494
PubMed Link to Article
Reeve  TSDelbridge  LBrady  PCrummer  PSmyth  C Secondary thyroidectomy: a twenty-year experience. World J Surg 1988;12 (4) 449- 453
PubMed Link to Article
Chao  TCJeng  LBLin  JDChen  MF Reoperative thyroid surgery. World J Surg 1997;21 (6) 644- 647
PubMed Link to Article
Pereira  JAJimeno  JMiquel  J  et al.  Nodal yield, morbidity, and recurrence after central neck dissection for papillary thyroid carcinoma. Surgery 2005;138 (6) 1095- 1100
PubMed Link to Article
Zarnegar  RBrunaud  LClark  OH Prevention, evaluation, and management of complications following thyroidectomy for thyroid carcinoma. Endocrinol Metab Clin North Am 2003;32 (2) 483- 502
PubMed Link to Article
Yamashita  HMurakami  TNoguchi  S  et al.  Postoperative tetany in Graves disease: important role of vitamin D metabolites. Ann Surg 1999;229 (2) 237- 245
PubMed Link to Article
Moriyama  TYamashita  HNoguchi  S  et al.  Intraoperative parathyroid hormone assay in patients with Graves' disease for prediction of postoperative tetany. World J Surg 2005;29 (10) 1282- 1287
PubMed Link to Article
Shaha  ARJaffe  BM Parathyroid preservation during thyroid surgery. Am J Otolaryngol 1998;19 (2) 113- 117
PubMed Link to Article
Singh  BLucente  FEShaha  AR Substernal goiter: a clinical review. Am J Otolaryngol 1994;15 (6) 409- 416
PubMed Link to Article
Güllüoğlu  BMManukyan  MNCingi  A  et al.  Early prediction of normocalcemia after thyroid surgery. World J Surg 2005;29 (10) 1288- 1293
PubMed Link to Article
Tartaglia  FGiuliani  ASgueglia  M  et al.  Randomized study on oral administration of calcitriol to prevent symptomatic hypocalcemia after total thyroidectomy. Am J Surg 2005;190 (3) 424- 429
PubMed Link to Article
Bellantone  RLombardi  CPRaffaelli  M  et al.  Is routine supplementation therapy (calcium and vitamin D) useful after total thyroidectomy? Surgery 2002;132 (6) 1109- 1112
PubMed Link to Article
Cahill  RAHarty  RCotter  SWatson  RG Parathormone response to thyroid surgery. Am J Surg 2006;191 (4) 453- 459
PubMed Link to Article
McLeod  IKArciero  CNoordzij  JP  et al.  The use of rapid parathyroid hormone assay in predicting postoperative hypocalcemia after total or completion thyroidectomy. Thyroid 2006;16 (3) 259- 265
PubMed Link to Article
Del Rio  PArcuri  MFFerreri  GSommaruga  LSianesi  M The utility of serum PTH assessment 24 hours after total thyroidectomy. Otolaryngol Head Neck Surg 2005;132 (4) 584- 586
PubMed Link to Article
Chia  SHWeisman  RATieu  D  et al.  Prospective study of perioperative factors predicting hypocalcemia after thyroid and parathyroid surgery. Arch Otolaryngol Head Neck Surg 2006;132 (1) 41- 45
PubMed Link to Article
Omdahl  JLGarry  PJHunsaker  LA  et al.  Nutritional status in a healthy elderly population: vitamin D. Am J Clin Nutr 1982;36 (6) 1225- 1233
PubMed
Gloth  FMGundberg  JMHollis  BW  et al.  Vitamin D deficiency in home-bound elderly persons JAMA 1995;274 (21) 1683- 1686
PubMed Link to Article
Atli  TGullu  SUysal  AR  et al.  The prevalence of vitamin D deficiency and effects of ultraviolet light on vitamin D levels in elderly Turkish population. Arch Gerontol Geriatr 2005;40 (1) 53- 60
PubMed Link to Article
Friedlander  JJanulis  MTembe  V  et al.  Loss of parathyroid hormone-stimulated 1,25-dihydroxyvitamin D3 production in aging does not involve protein kinase A or C pathways. J Bone Miner Res 1994;9 (3) 339- 345
PubMed Link to Article
Nordin  BECNeed  AGMorris  HAO’Loughlin  PDHorowitz  M Effect of age on calcium absorption in postmenopausal women. Am J Clin Nutr 2004;80 (4) 998- 1002
PubMed
Alagöl  FShihadeh  YBoztepe  H  et al.  Sunlight exposure and vitamin D deficiency in Turkish women. J Endocrinol Invest 2000;23 (3) 173- 177
PubMed Link to Article
LeBoff  MSKohlmeier  LHurwitz  S  et al.  Occult vitamin D deficiency in postmenopausal US women with acute hip fracture. JAMA 1999;281 (16) 1505- 1511
PubMed Link to Article
Webb  ARPilbeam  CHanafin  NHolick  MF An evaluation of the relative contributions of exposure to sunlight and of diet to the circulating concentrations of 25-hydroxyvitamin D in an elderly nursing home population in Boston. Am J Clin Nutr 1990;51 (6) 1075- 1081
PubMed
Need  AGHorowitz  MMorris  HANordin  BC Vitamin D status: effects on parathyroid hormone and 1,25 dihydroxyvitamin D in postmenopausal women. Am J Clin Nutr 2000;71 (6) 1577- 1581
PubMed
Haden  STFuleihan  GEAngel  JECotran  NMLe Boof  MS Calcidiol and PTH levels in women attending an osteoporosis program. Calcif Tissue Int 1999;64 (4) 275- 279
PubMed Link to Article
Kinyamu  HKGallagher  JCRafferty  KABalhorn  KE Dietary calcium and vitamin D intake in elderly women: effect on serum parathyroid hormone and vitamin D metabolites. Am J Clin Nutr 1998;67 (2) 342- 348
PubMed

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