European Journal of Cardiovascular Medicine

The normal thyroid gland weighs 20-25 g. The functioning unit is the lobule supplied by a single arteriole and consists of 24-40 follicles lined with cuboidal cpithelium¹. A retrosternal goiter is an enlarged thyroid which extends below clavicle and sternum. Retrostemal goitre can be defined as thyroid which extends below manubrium but some include only goitres that extends more than 50% or 3 cm below thoracic inlet. Because they are expansions or extensions of multinodular goitres based on the superior or inferior thyroid vasculature, the majority of intrathoracic or substernal goitres are referred to be secondary." They spread outward into the mediastinum anterior² 

Substernal, intrathoracic, cervico-thoracic, and endothoracic are some more terms. Albrecht von Haller originally defined retrosternal goitre (RG) in 1749 as the protrusion of the thyroid tissue behind the chest's upper aperture. Because of the potential complications during surgical removal, RG has since been seen as a challenge for surgeons. With a 3:1 ratio, it has a stronger female preponderance. The fifth or sixth decade of life is when RG is most commonly diagnosed, with a 4:1female to male ratio.^3,4

The most typical symptoms, which include dyspnea, choking, difficulty sleeping, dysphagia, and hoarseness, are caused by constriction of the oesophag us and airways. Less frequently, symptoms such as Horner's syndrome (compression of the sympathetic chain) and/or superior vena cava blockage (superior vena cava syndrome) indicate compression of vascular and neurological structures.⁵.

The uncommon (about 1% of cases) primary substernal goitre originates from abnormal thyroid tissue in the front or posterior mediastinum; it is not supplied by the inferior thyroid artery but rather relies on the intrathoracic vasculature. Typically, radiological tests are used to confirm the clinical diagnosis⁶.

Even in the absence of clinical symptoms, surgical excision is generally acknowledged as the best course of treatment for RG. A partial or complete sternotomy should only be done in a small percentage of patients—between 1 and 11 percent—while the majority of RGs can be removed via a cervical approach. The operative technique used to operate retrosternal goitre is based on the extension of goitre and its accessibility. It can be done using cervical approach only if dissection and removal is possible, otherwise it mandates a Median Sterotomy for visualisation, dissection and removal of goitre⁷. This study was done to find out the differences for the need for cervical approach or if it mandates a median sternotomy based on various factors.

 Justification for the Study

To analyse the difference between the cervical approach and the need for sternotomy in operating retrosternal goitre and to find and minimise the need for sternotomy for better patient post-operative period and outcome.

Aim

To analyse the difference between the need for sternotomy and the need for only cervical approach in operating retrosternal goitre.

and Hospital over the past 10 years from period 2013-2023. Every patient who had a chest X-ray showing tracheal deviation or a mediastinal mass, or who had a clinical suspicion of retrosternal extension of the goitre (lower pole of the cervical goitre not palpable), had a CT scan done prior to surgery.

Inclusion criteria

1. All cases of retrosternal goitre

Exclusion criteria

1. All other thyroid pathologies except retrosternal goitre.
2. This study did not include any patients whose goitre had a slight mediastinal expansion.

Methodology

1. Retrospective data collection of all cases of retrostemal goitre operated in PSGIMSR and hospital during the year 2013-2023 was collected.
2. Patient details, history, relevant investigations, operating procedure, post-operative complications and duration of hospital stay was collected.
3. General Surgeons with Expertise in Thyroid Surgery carried out all of the procedures. When a CT scan was taken with the neck stretched excessively and the goitre extended at least 3 cm below the cervico-thoracic isthmus, it was classified as retrosternal.
4. The clinical symptoms, prior thyroidectomy history, presence of tracheal deviation (treason of the trachea from the normal midline position) or tracheal compression (tracheal lumen reduction), site of mediastinal extension (anterior or posterior in relation to the trachea's centre in the antero-posterior plane), type of surgical approach (only cervical or cervical with median sternotomy), thyroid histology findings, thyroid weight, and post-operative complications were examined in these patients' records.  
   After data was gathered, statistical analysis was performed.

Statistical analysis

A statistician assisted in tabulating the data that was gathered in an Excel sheet. For statistical analysis, the means and standard deviations of each group's measurements were employed (SPSS 24.00 for Windows; SPSS Inc., Chicago, USA). The t test and chi square test were used to compare the two groups, and a significance level of p < 0.05 was established.

Of the thirty-one patients, twenty-six (83.87%) had a thyroidectomy via a cervical incision, and five (16.13%) required a median sternotomy to eliminate the goitre safely. Females were comparatively more as compared to males. Mean age among the subjects who underwent surgery through cervical and thoracic approach was 56±13.11 and 48.67±17.28 years respectively (Table 1).

Symptoms viz. neck swelling, respiratory (dyspnea/ cough/choking), dysphagia, neck discomfort and hoarsness of voice was reported in 90.32%, 51.61%, 9.68%, 9.68% and 6.45% of the subjects respectively (table 2, graph 2).

Mean operative time (min) and hospital stay (days) among subjects who underwent surgery through cervical and thoracic approach was 214.81, 7.92 and 321.92, 15.83 respectively. Hence mean operative time (min) and hospital stay (days) was significantly more in thoracic as compared to cervical approach as p<0.05 (table 3). 

Most common postoperative complications among the study subjects was transient hypocalcemia followed by postoperative bleeding (table 4).

In this current study, 26 patients (83.87%) received thyroidectomies via cervical incisions, whereas 5 patients (16.13%) required median sternotomies to safely remove the goitre. Compared to the figures often reported in the literature, this indicates a slightly higher incidence of sternotomy. The stringent and severe criteria included in the definition of RG⁸ could be the cause. For most individuals, a cervical approach can be used for RG surgical removal. It has been observed that in 2-5% of thyroidectomies for RG, experienced head and neck surgeons with good thyroid surgical experience must conduct an extra-cervical approach; nonetheless, some authors have reported a sternotomy incidence of 29% of patients⁹. This variation may be connected to the inconsistent definition of RG. At first, a goitre that extended below the thoracic inlet was often regarded as retro-sternal¹⁰. RG could be removed using a conventional cervical technique in 49/53 individuals, according to a research by M.G. Rugiuetal¹¹, even though the goitres' mediastinal extension was deep and extensive.
There is still no widespread agreement on the precise factors that increase the risk of sternotomy, despite several attempts to identify them. The sternotomic technique was deemed "inevitable" by Flatietal¹² in 2005 when there was an iceberg-shaped RG with more than 70% of the bulk located in the mediastinum. Later, in 2007, de Perrot et al¹³ emphasised the necessity of a sternotomy for goitres larger than 10 cm, for patients who had previously undergone a cervical thyroidectomy, and when aggressive cancer or an ectopic goitre is present. Only 3/140 patients with RG had a sternotomy performed by Burns et al¹⁴ because, in their view, the two most important factors raising the possibility that a sternotomy is necessary are CT evidence of adherence to the surrounding mediastinal tissues and goitre extension to or below the aortic arch. Based on a comprehensive analysis of the literature, White et al. (2008) hypothesised that sternotomy is more likely to be carried out when there is a main RG or a mass bigger than the thoracic inlet.

Females were comparatively more as compared to males. Mean age among the subjects who underwent surgery through cervical and thoracic approach was 56±13.11 and 48.67±17.28 years respectively. Diamantis I. Tsilimigrasetal¹⁵ in their study too revealed that the majority of mediastinal goitres are diagnosed in the sixth decade of life with a female to male ratio of 3:1.

Symptoms viz. neck swelling, respiratory (dyspnea/ cough/choking), dysphagia, neck discomfort and hoarsness of voice was reported in 90.32%, 51.61%, 9.68%, 9.68% and 6.45% of the subjects respectively. According to Saurabh Varshney et al¹⁶, respiratory issues transpired in 46.8% of the instances, owing to constriction of either the oesophagus or the trachea, or both. The disease's progressive nature and the inlet's small path contributed to this problem.

Mean operative time (min) and hospital stay (days) among subjects who underwent surgery through cervical and thoracic approach was 214.81, 7.92 and 321.92, 15.83 respectively. Hence mean operative time (min) and hospital stay (days) was significantly more in thoracic as compared to cervical approach as p<0.05.

Transient hypocalcemia and postoperative haemorrhage were the most frequent surgical complications among the study participants. Following thyroid surgery, the incidence of both temporary and permanent RLN palsy has been reported to be 2.3% and 9.8%, respectively. In contrast, 5.36% (6 patients) and 0.89% (1 patient) of our patients had transitory and persistent RLN palsy, respectively. According to Xu Wang et al.'s¹⁷ study, all six temporary RLN instances had good signals during the procedure, with the recurrent laryngeal nerve functioning normally. Nerve monitoring was utilised to identify nerve signals during the resection. Following thyroid surgery, the most common consequences are hypocalcemia and hypoparathyroidism. The risk of hypocalcemia is increased after surgery for retrosternal goitre because it is more challenging to locate the parathyroid glands. Hypoparathyroidism is defined as postoperative serum PTH below 14.5 pg/mL and postoperative hypocalcemia as serum calcium below 2.11 mmol/L.

Using a CT scan to estimate the thyroid volume prior to surgery can help identify which individuals are most likely to benefit from a thoracic approach.

Surgery for retrosternal goitres presents difficulties for surgeons. The examination of the CT scan should be used to establish the optimal surgical strategy. The most crucial elements for surgery are the intact capsule and the distinct separation between the retrosternal goitre and the surrounding tissue. Using every option at hand, an attempt should always be made to remove the goitre through the cervical incision, as there is a lower chance of surgical and aesthetic harm associated with this strategy. The most important factors in determining which patients need sternotomies are the characteristics of the CT scan, including the presence of an ectopic goitre, the volume of the thyroid gland, and if the goitre extends to or below the tracheae carina. As a result, whenever RSG is suspected, the CT scan has to be a part of the pre-operative diagnostic evaluation. Nevertheless, the ultimate determination of whether to execute a sternotomy must be made during the surgical procedure, and the decision is contingent upon the surgeon's experience. Most retrosternal goitres can be surgically removed with cervical surgery if the procedure is planned and carried out well beforehand and is performed with great care during the procedure.

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