Clinical course of incidental parathyroidectomy: Single center experience

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Clinical course of incidental parathyroidectomy: Single center experience Sabri Özden a,*, Ahmet Erdo gan b, Besir Simsek c, Baris Saylam a, Baris Yıldız a, Mesut Tez a a

Department of Surgery, Ankara Numune Training and Research Hospital, Ankara, Turkey Department of Surgery, Ankara Oncology Training and Research Hospital, Ankara, Turkey c Department of Surgery, Batman State Hospital, Batman, Turkey b

A R T I C L E I N F O

A B S T R A C T

Article history: Received 5 May 2017 Accepted 27 July 2017 Available online xxx

Objective: Thyroidectomy is a very common surgical procedure. Regardless of surgeon experience, incidental parathyroidectomy is a complication of thyroidectomy. The aim of this study was to identify the clinical course of incidental parathyroidectomies after thyroidectomy. Methods: Patients who underwent thyroidectomy between January 2010 and June 2014 were evaluated retrospectively. Pathology reports were reviewed for the presence of parathyroid tissue in the thyroidectomy pathology specimens. Information regarding demographic, laboratory variables, operative details, and postoperative complications were collected. Results: Incidental parathyroidectomy was found in 178 out of 3022 patients who had thyroidectomy (5.8%). Types of surgeries performed for 178 patients were total thyroidectomy (TT) in 132(74.2%) cases, TT and central lymph node dissection(CLND) in 30 (16.9%) cases, lobectomy in seven cases (3.9%), completion thyroidectomy in five (2.8%) patients and modified cervical lymph node dissection in four (2.2%)patients. One and two parathyroid glands were accidentally removed in 152 (85.3%) and 26 (14.7%) patients, respectively. In the entire series, biochemical temporary postoperative hypocalcemia occurred in 75(42.1%) patients and permanent hypocalcemia occured in 12 (6.7%) patients with incidental parathyroidectomy. There was not a statistically significant difference regarding the occurrence of postoperative permanent hypocalcemia between the patients who had incidental parathyroidectomy of one gland and the patients with two incidental parathyroidectomies (p = 0.114). Conclusion: Incidental parathyroidectomy is not uncommon during thyroidectomy. No association between inadvertent parathyroidectomy and postoperative permanent hypocalcemia was found. © 2017 Elsevier B.V.. All rights reserved.

Keywords: Incidental parathyroidectomy Inadvertent parathyroidectomy

1. Introduction Thyroidectomy is a common, relatively safe surgical procedure. The main postoperative complications of thyroid-

* Corresponding author at: Department of Surgery, Breast and Endocrine Surgery Section, Ankara Numune Training and Research Hospital, Talatpasa Boulevard n.5, Altindag, Ankara, Turkey. E-mail address: [email protected] (S. Özden).

ectomy include injury to the parathyroid glands and to the recurrent laryngeal nerves. The reported incidence of symptomatic hypocalcemia after thyroidectomy ranges between 10– 36%. Symptomatic hypocalcemia may be due to a variety of factors, such as injury, devascularization of the parathyroid glands, and accidental resection of parathyroid glands. Clinical relevance of incidental parathyroidectomy remains obscure [1–5].

http://dx.doi.org/10.1016/j.anl.2017.07.019 0385-8146/© 2017 Elsevier B.V.. All rights reserved.

Please cite this article in press as: Özden S, et al. Clinical course of incidental parathyroidectomy: Single center experience. Auris Nasus Larynx (2017), http://dx.doi.org/10.1016/j.anl.2017.07.019

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Table 1 Types of surgical procedures and histopathology of thyroid specimens where incidental parathyroidectomy has occurred. Procedure

Incidental parathyroidectomy (n)

Total (n)

Total thyroidectomy Total thyroidectomy and central lymph node dissection Thyroid lobectomy Completion thyroidectomy Modified cervical lymph node dissection Total

132 (5.2%) 30 (19.3%) 7 (6.3%) 5 (2.6%) 4 (10.5%) 178

2530 155 110 189 38 3022

Histopathology of thyroid Benign disease Malignancy Total

112 (5.3%) 66 (7.2%) 178

2112 910 3022

The aim of the present study is to analyze our experience regarding the incidence of incidental parathyroidectomy and its clinical course. 2. Materials and methods A total of 3022 thyroidectomies were performed between January 2010 and June 2014 at the Ankara Numune Training and Research Hospital (Table 1). Thyroid malignancy was documented preoperatively by fine-needle aspiration biopsy. Cases, where parathyroid tissue was sent separately for histologic evaluation for another reason, were not included in this study. The following data were recorded: gender, age, details of surgical procedures, histological findings, the number of parathyroid glands identified at the specimen, and Table 2 Patient demographics, preoperative diagnosis, operative procedures, histological findings, and postoperative permanent hypocalcemia. Variable

Number of patients (n)

Gender Male Female

152 (85.4%) 26 (14.6%)

Age (years) Mean  SD Range

47.7  12.9 14–79

Preoperative diagnosis Benign Malignant

122 (68.5%) 56 (31.4%)

postoperative symptomatic hypocalcemia (transient or permanent) (Table 2). All thyroidectomy procedures were performed by surgeons with experience in thyroid surgery. Attempt to identify the recurrent laryngeal nerve was a routine policy. Suction drainage was used routinely. If inadvertent removal was recognized during surgery, removed parathyroid glands were autotransplanted. These cases were not included in this study. Postoperative hypocalcemia was defined as permanent when parathyroid hormone was undetectable, or calcium or vitamin D supplementation exceeded 6 months postoperatively to treat clinical symptoms of hypocalcemia. 2.1. Statistical analysis Comparisons were made for incidental parathyroidectomy and postoperative transient or permanent hypocalcemia. Univariate analysis was performed using a t test, and categorical values were determined using the x2 test. p < 0.05 was considered statistically significant. 3. Results

Procedure Total thyroidectomy 132 (74.2%) Total thyroidectomy and central lymph node dissection30 (16.9%) Thyroid lobectomy 7 (3.9%) 5 (2.8%) Completion thyroidectomy Modified cervical lymph node dissection 4 (2.2%) Final thyroid pathology Benign Malignant

112 (62.9%) 66 (37.1%)

Incidental parathyroidectomy Intrathyroidal Extrathyroidal

30 (16.8%) 148 (83.1%)

One hundred seventy-eight patients were identified with incidental parathyroidectomy out of 3022 patients (5.8%). 910 (30.1%) patients had thyroid malignancy and 2112 (69.9%) patients had benign thyroid disease out of these 3022 patients at final histopathologic examination. 112 (5.3%) patients who had benign thyroid disease and 66 (7.2%) patients who had thyroid malignancy, have incidental parathyroidectomy (Table 1). Types of surgical procedures performed for these 178 patients were total thyroidectomy (TT) in 132 (74.2%) cases, TT and central lymph node dissection (CLND) in 30 (16.9%) cases, lobectomy in seven cases (3.9%), completion thyroidectomy in five (2.8%) cases and modified cervical lymph node dissection in four (2.2%) cases (Table 1). Histopathologic examination of the resected thyroid specimens revealed the presence of benign thyroid disease in 112 (62.9%) cases and thyroid malignancy in 66 (37.1%) cases (Table 2). One and two parathyroid glands were accidentally removed in 152 (85.3%) and 26 (14.7%) patients, respectively. There were not any incidental removals of more than 2 parathyroid glands.

Please cite this article in press as: Özden S, et al. Clinical course of incidental parathyroidectomy: Single center experience. Auris Nasus Larynx (2017), http://dx.doi.org/10.1016/j.anl.2017.07.019

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In the entire series, biochemical temporary postoperative hypocalcemia occurred in 75(42.1%) patients and permanent hypocalcemia occurred in 12 (6.7%) patients with incidental parathyroidectomy. There was not a statistically significant difference regarding the occurrence of postoperative permanent hypocalcemia between the patients with one incidental parathyroidectomy and the patients with two incidental parathyroidectomies (p = 0.114). Univariate analysis did not reveal the type of thyroidectomy as a risk factor for permanent hypocalcemia (p = 0.646). There were 155 patients who had undergone CLND. In this group, 30 (19.3%) patients had incidental parathyroidectomy. There was a statistically significant difference (p = 0.0001) between CLND and the other surgical procedure types for the occurrence of incidental parathyroidectomy. The further histopathological inspection revealed that the parathyroid tissue in the resected specimen was found to be intrathyroidal in 30 (16.8%) cases (i.e., parathyroid tissue completely contained within the thyroid capsule or completely surrounded by thyroid tissue).

[4,10,12,13,15]. This rate was 16.8% in our study. In such situations, advances in surgical technique cannot eliminate the risk of incidental parathyroidectomy. In our study, 66 (37.1%) cases had malignancy at final pathology. High incidence of malignancy may indicate that malignancy might be an additional risk of incidental parathyroidectomy [7– 12,16]. The reason of this state might be explained by more aggressive surgery in malignancy [8,9].

4. Discussion

References

Iatrogenic hypoparathyroidism is a common complication after thyroidectomy. In literature, the incidence of incidental parathyroidectomy during thyroid surgery ranges between 8 to 24.9% [3–11]. In this study, we observed inadvertent parathyroidectomy in 5.8% of our patients. In most of the reports in the literature, mostly one parathyroid gland was resected with the thyroid [2– 7,10,12,13]. This was similar to our series as one parathyroid gland was accidentally removed in 152 (85.3%) cases. LorentePoch et al. published a recent prospective study about incidental parathyroidectomy. In this study, the prevalence of hypocalcemia, and permanent hypoparathyroidism was related to the number of parathyroid glands left in situ [14]. In our study, permanent hypocalcemia was not associated with either of one or two incidental parathyroidectomies. This may indicate that, like the study of Lorente-Poch et al., parathyroid glands left in situ is the actual factor for permanent hypoparathyroidism. In our study, inadvertent parathyroidectomy incidence was higher (19.3%) at CLND group than other surgery types. This was statistically significant (p = 0.0001). It is not surprising that with more extensive procedures, inadvertent parathyroidectomy occurs more frequently although we did not observe an increase in the incidence of inadvertent parathyroidectomy at modified cervical lymph node dissection. Overall, when permanent hypocalcemia was considered, there was not a statistically significant difference (p = 0.646) between surgical procedure types. Although experienced surgeons have highlighted the importance of parathyroid identification and preservation during thyroidectomy, taking the greatest possible care to localize, dissect, and preserve the parathyroid glands, inadvertent removal of parathyroids may occur [8,9,12]. The variable locations of the parathyroid glands add to the risk of incidental parathyroidectomy. Incidentally excised parathyroid glands were reported to be intrathyroidal in up to 40–50% of cases

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5. Conclusion Incidental parathyroidectomy is not uncommon during thyroidectomy. No association between inadvertent parathyroidectomy and postoperative permanent hypocalcemia was found. Inadvertent parathyroidectomy may be considered as a minor complication of thyroidectomy. Funding There is not any funding.

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Please cite this article in press as: Özden S, et al. Clinical course of incidental parathyroidectomy: Single center experience. Auris Nasus Larynx (2017), http://dx.doi.org/10.1016/j.anl.2017.07.019