Hamdan Medical Journal

ORIGINAL RESEARCH ARTICLE
Year
: 2018  |  Volume : 11  |  Issue : 1  |  Page : 17--21

Complication rates of thyroidectomy by an experienced, high-volume thyroid surgeon in a private hospital in Abu Dhabi, United Arab Emirates


Zahoor Ahmad1, Ammar Kutaiman1, Youssef Hassan2, Peshraw Amin3, Mohammad Amjad Khan4,  
1 General Surgery Department, Alnoor Hospital Khalifa Street, Abu Dhabi, UAE
2 Department of Endocrinology, Alnoor Hospital Airport Road, Abu Dhabi, UAE
3 Department of Endocrinology, Alnoor Hospital Khalifa Street, Abu Dhabi, UAE
4 Department of Statistics, Govt. Degree College Akbarpura, KPK, Pakistan

Correspondence Address:
Dr. Zahoor Ahmad
Department of General Surgery, Al Noor Hospital, Abu Dhabi
UAE

Abstract

Background: Thyroidectomy is one of the most common endocrine surgical procedures; it is performed by surgeons of various specialities including general surgeons, endocrine surgeons, ear, nose and throat (ENT) surgeons and head and neck surgeons. Thyroidectomy carries a significant and immediate risk of complications, some of which can be life threating. Improved surgical techniques and surgeons experienced in thyroid surgery can significantly reduce morbidity and mortality. Objective: The objective of this prospective study was to determine the overall complication rate and demonstrate that a permanent complication rate of 0% can be achieved. Study Design and Settings: The study was carried out between January 2013 and May 2015 and involved 228 patients. All patients were assessed preoperatively by an endocrinologist and an ENT surgeon for vocal cord functions; all were operated on by the same surgeon, who had >10 years' experience and performed over 100 thyroidectomies per year. Patients were followed up at 6 months to record any complications. Data were analysed using SPSS version 13.0 (IBM, Armonk, NY, USA) and a Chi-squared test was used to calculate P values. Results: There was an overall complication rate of 16.23%; 15.8% of patients experienced transient hypocalcaemia and 0.4% experienced post-operative bleeding. There were no permanent complications, and the rate of both recurrent laryngeal nerve injury and wound infection was 0%. Conclusion: We conclude that the rate of complications of thyroidectomy can be significantly reduced and the rate of permanent complications reduced to 0% if the procedure is performed by an experienced, high-volume surgeon with a special interest in thyroid surgery.



How to cite this article:
Ahmad Z, Kutaiman A, Hassan Y, Amin P, Khan MA. Complication rates of thyroidectomy by an experienced, high-volume thyroid surgeon in a private hospital in Abu Dhabi, United Arab Emirates.Hamdan Med J 2018;11:17-21


How to cite this URL:
Ahmad Z, Kutaiman A, Hassan Y, Amin P, Khan MA. Complication rates of thyroidectomy by an experienced, high-volume thyroid surgeon in a private hospital in Abu Dhabi, United Arab Emirates. Hamdan Med J [serial online] 2018 [cited 2018 Oct 24 ];11:17-21
Available from: http://www.hamdanjournal.org/text.asp?2018/11/1/17/228865


Full Text



 Introduction



Disorders of the thyroid gland are very common in the general population, and thyroidectomy is one of the most common endocrine surgical procedures. Theodor Kocher was the first to describe thyroidectomy scientifically, decreasing morbidity and mortality rates, and clinical outcomes continue to improve as technical understanding increases.[1],[2],[3]

Thyroidectomy is performed by a variety of surgeons including general, endocrine, ear, nose and throat (ENT) and head-and-neck surgeons.[2] The extent of resection ranges from lobectomy to total thyroidectomy.[4] Despite improved techniques and a greater understanding of the procedure, thyroidectomy continues to carry a significant risk of morbidity and mortality. Complications range from minor to life threatening and can be transient or permanent.[1],[2],[5],[6],[7] The two major complications are laryngeal nerve palsy and hypocalcaemia (hypoparathyroidism). The reported incidence of permanent laryngeal nerve palsy ranges from 0% to 18.6%, whereas the incidence of temporary laryngeal nerve palsy ranges from 1.4% to 38%. The corresponding figures for hypocalcaemia are 1.2%–11%[1],[7],[8] and 1%–40%, respectively.[1],[5],[9]

Various factors have been shown to affect the occurrence of complications such as the extent of resection, surgeon experience and volume, surgical technique, redo surgery and the nature and type of thyroid disease.[2],[5],[6],[8] It has been shown that experienced, high-volume surgeons have superior outcomes to inexperienced, low-volume surgeons owing to improved techniques developed and refined over time.[2],[4],[6],[7],[8],[10] Surgeons are defined as high volume if they perform >100 cases per year, intermediate if they perform 10–100 cases per year and low volume if they perform <10 cases per year.[11]

The objective of this study was to determine the overall rate of complication of thyroidectomy by a high-volume surgeon with >10 years' experience and a special interest in thyroid surgery and to achieve a permanent complication rate of 0%. We analysed the impact of various factors on complication rates such as patient age, sex, type of thyroidectomy, type of goitre and goitre pathology (malignant or benign) and toxicity.

 Materials and Methods



This prospective study was conducted in the General Surgery Department of Mediclinic Al Noor Hospital, Abu Dhabi, the United Arab Emirates, between January 2013 and May 2015 and involved 228 patients. Sample size was calculated using an 18.5% incidence rate of post-operative thyroidectomy complication,[7] a 95% significance level and a 5% margin of error. All patients aged >13 years who presented with goitres were included, irrespective of patient sex, goitre size and whether the goitre was malignant or benign, toxic or non-toxic or a multinodular goitre (MNG), solitary thyroid nodule or diffuse. Patients with osteoporosis, concomitant hyperparathyroidism or clinically enlarged neck nodes that required neck dissection were excluded from the study.

All patients were assessed in outpatient clinics by thorough clinical examination, blood test, imaging of the neck and fine-needle aspiration cytology. Patients were evaluated preoperatively by anaesthetists, endocrinologists and ENT surgeons for vocal cord functions and by other specialists as required. Patients with hyperthyroidism were made clinically and biochemically euthyroid before surgery. All operations were performed by the same consultant surgeon, who had >10 years' experience in thyroid surgery. Surgeries were performed using standard open thyroidectomy techniques: capsular dissection and the use of ligatures for tying vascular pedicles. Every attempt was made to save the parathyroid glands by ligating the individual branches of the inferior thyroid artery to keep its vascularity; if parathyroid glands were accidentally removed, these were reimplanted into the sternomastoid muscle.

We did not perform extensive exploration for recurrent laryngeal nerve (RLN) identification except in patients with very large, difficult goitres in whom there was a high risk of nerve injury owing to its displaced position; rather, we avoided the nerve by performing capsular dissection. This strategy was adopted to decrease the likelihood of transient RLN injury or dysfunction by excessive manipulation. Every patient was left with a suction drain in their thyroid bed. The vocal cords of all patients were examined for mobility by an anaesthetist at the time of extubation.

Serum calcium was measured in all patients on the morning after surgery, or earlier if the patient developed symptoms of hypocalcaemia; during follow-up visits, patients were examined for bleeding, changes to their voice and wound infection. Patients with a serum calcium concentration of <8.4 mg/dl were considered hypocalcaemic and treated with either oral or intravenous therapy depending on their serum calcium level and symptoms. Patients with impaired vocal cord mobility and marked hoarseness were considered to have an RLN injury. All patients were followed up in the outpatient clinic after 3 days, 1 week and 4 weeks. Patients with hypocalcaemia and RLN injury were followed up at 6 months. If they had recovered fully before 6 months, the complications were defined as transient; otherwise, they were defined as permanent.

The data were entered and analysed using SPSS version 13.0 (IBM, Armonk, NY, USA). Frequencies and percentages were calculated and a Chi-squared test was used to identify factors that significantly affected complications, using a 95% significance level and a 5% margin of error. P < 0.05 was considered statistically significant.

 Results



A total of 228 patients were included: 61.8% were aged <46 years, the majority (74.6%) were female, 80.3% had benign goitres and the most commonly performed operation was total thyroidectomy [Table 1].{Table 1}

The overall complication rate was 16.23%, with no permanent complications. Transient post-operative hypocalcaemia was the most frequent complication, present in 15.8% of cases. We did not encounter any cases of RLN injury or wound infection. Post-operative bleeding occurred in only one patient [Table 2]. There was no statistically significant effect of goitre type, pathology, toxicity or type of thyroidectomy on the rate of hypocalcaemia [Table 3]. Hyperthyroidism had a statistically significant effect on post-operative bleeding (P = 0.008) [Table 4].{Table 2}{Table 3}{Table 4}

 Discussion



Today, thyroidectomy is considered a very safe procedure, but it is not entirely free from complications. Some of the immediate complications are life threatening if not recognised and treated promptly, whereas others, such as hypocalcaemia and RLN injury, add significant morbidity, particularly if they are permanent. Various factors influence the occurrence of these complications such as extent of resection, operating surgeon's experience, volume and size of goitre and goitre pathology and toxicity. The majority of these complications can be minimised or prevented if performed by an experienced, high-volume surgeon with a special interest in thyroid surgery.[2],[3],[8],[10]

The overall rate of complication in this study was 16.23%, and all complications were transient. The rates of post-thyroidectomy complication reported in the literature vary widely. Although some authors have reported a lower overall rate of complication than in this study, all have reported permanent complications; there was not one case of permanent complication in this study.[2],[8],[12] On the other hand, we reported a lower rate of complication than many other studies in the literature.[3],[5],[7],[13] No transient complications in this study adversely affect the quality of life of patients, who were free from symptoms 1 week after surgery.

The most common post-operative complication of thyroidectomy is hypocalcaemia, which may be symptomatic or asymptomatic. Hypocalcaemia is most commonly caused by post-operative parathyroid insufficiency due to incidental removal of one or more glands, stunning and devascularisation of the glands. However, transient post-operative hypocalcaemia can be caused by haemodilution, increased urinary excretion due to surgical stress, calcitonin release and hungry bone syndrome in patients with hyperthyroidism.[14],[15],[16],[17] In this study, the rate of hypocalcaemia was 15.8%. None of those hypocalcaemic patients required calcium supplements after 2 weeks. Some authors have reported a lower incidence of post-operative hypocalcaemia than we reported in this study (as low as 3.5%),[2],[7],[17] whereas several other studies have reported a higher incidence of hypocalcaemia (as high as 59%).[4],[13],[14],[16] The majority of studies with lower rates have encountered some form of permanent hypoparathyroidism (hypocalcaemia), which greatly impairs the patient's quality of life. In comparison, we did not encounter any permanent hypocalcaemia. All patients with transient hypocalcaemia did not require calcium supplements after 2 weeks. The overall incidence in this study is on the lower side of the reported data in the literature; more significantly, we have achieved the lowest possible rate of permanent hypocalcaemia.[4],[5],[9],[12],[14]

We looked at the impact of various other factors such as age, sex, type and extent of thyroidectomy, type of goitre and goitre pathology and toxicity. None of these was found to have a statistically significant effect on the rate of hypocalcaemia, similar to findings reported in the majority of studies.[7],[17],[18] Few studies have reported statistically significant effects of the type of thyroidectomy, toxic MNG, malignant goitres, age and female sex on post-operative hypocalcaemia; however, these findings have not been reported together in any individual study but scattered across multiple studies.[7],[17]

One of the most serious complications of thyroidectomy is RLN injury because it adds significant disability, particularly in its permanent form. None of our patients experienced RLN injury, whether transient or permanent. The incidence of RLN injury reported in the literature varies from 2% to 17%.[2],[4],[7],[19],[20] Some studies reported no permanent RLN injury but occasional transient RLN injury.[21],[22] Thyroid surgeons have differing views on how to prevent RLN injury: some recommend direct visualisation of the RLN or intraoperative nerve monitoring to reduce the risk of permanent RLN injury,[9],[20],[23] while others recommend avoiding the routine exploration of the RLN as this increases the incidence of transient RLN injury.[19],[23] We believe that the 0% rate of RLN injury achieved can be attributed to two factors: the surgical technique employed and the large number of procedures performed by the operating surgeon. We did not explore the RLN extensively in easy and small goitres with intact tissue planes and more predictable course of the nerve in small goitres; we avoided the nerve to minimise temporary RLN injury. However, we explored and identified the nerve in more difficult cases, such as large goitres, tissue planes distorted by inflammation in thyroiditis, infiltrating malignant goitres and redo cases, in which the nerve is usually displaced or incorporated into the inflamed tissue, resulting in a high risk of transection causing permanent damage.[4],[7],[8],[10],[19],[23]

On the basis of these observations, and in contrast to the majority of studies, we do not recommend the avoidance of routine identification of the RLN during thyroidectomy. However, we attribute the absence of any type of RLN injury in this study to the experience of the high-volume surgeon, who employed both techniques preferentially: identifying the RLN in some cases and avoiding it in others. To recommend against routine identification of the RLN, large and long-term studies are required.

Post-operative bleeding is one of the most life-threatening complications of thyroidectomy. Only one of our patients developed post-operative bleeding (0.4%), which was detected early because of an unusual increase in the output of the suction drain. This was re-explored immediately, a small haematoma was found and a small bleeding vessel was ligated; the patient's condition was not compromised. Our rate of post-operative bleeding is well within the incidence range reported in the international literature of 0% to 5%;[2] a recent American study reported an incidence of 2.3%.[24] We observed a statistically significant effect of toxic MNG on the rate of post-operative bleeding. Zambudio et al.[7] have observed similar effects on post-operative bleeding from hyperthyroidism (toxicity). The single case of post-operative bleeding in this study was observed in a young male with a long-standing toxic MNG; although he was made euthyroid before surgery, toxic goitres retain their increased vascularity and are prone to post-operative bleeding.[7]

In this study, we did not use any prophylactic antibiotics beyond strictly observing the standard sterile precautions in the perioperative period. Our rate of post-operative wound infection was 0%. In the literature, the incidence of wound infection has been reported as up to 2%.[2],[22]

 Conclusion



The rate of complication of thyroidectomy can be significantly reduced, and the rate of permanent complication reduced to 0%, if performed by an experienced, high-volume surgeon with a special interest in thyroid surgery.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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