Surgical resection
Surgical decisions were guided using an institutional treatment
algorithm (Figure 1). If extracervical access was not
necessary, patients were managed using a cervical approach only through
digital dissection and upwards traction of the goiter. Where an
extracervical approach was indicated, surgical management was guided by
the extent and direction of inferior extension.
Anterior
goiters above the level of the pericardium were resected using cervical
thyroidectomy with either mediastinoscopic-assisted delivery or cervical
thyroidectomy with video- assisted thyroidectomy (VATS). Those extending
beyond the pericardium instead required median sternotomy to facilitate
sufficient vascular control and exposure.
Goiters
extending into the posterior mediastinum were managed using
trans-thoracic approaches, this time via the posterolateral route such
as a lateral thoracotomy or VATS.
Results
Case
one
A 59-year-old male presented with an enlarged neck mass and voice
changes. CT imaging revealed an enlarged thyroid gland with retrosternal
extension to T4 in contact with, but not beyond, the aortic arch in the
anterior mediastinum (Figures 2a and 2b). He underwent a total
thyroidectomy via Kocher’s incision where the strap muscles were
divided, and the thyroid gland was mobilised using subcapsular
dissection technique. The superior, lateral, posterior, and much of the
inferior poles of the thyroid gland were freed using forceps dissection
before upward traction applied to the superior poles delivered the
gland’s mediastinal component (Figures 2c and 2d). The patient
had an uneventful recovery and was discharged on postoperative day two.
The final histology confirmed benign nodular hyperplasia.
Case
two
A 59-year-old female presented with dysphagia and a CT scan
demonstrating an enlarged thyroid gland with an anterior mediastinal
component connected via a fibrous stalk. Total thyroidectomy was
performed as described in case one, however, the fibrous stalk did not
allow for traction delivery of the mediastinal component. Instead, the
stalk was amputated, the cervical goiter was delivered via the neck
incision, and the remaining mediastinal component was removed with an
extracervical approach using VATS.
The right lateral chest wall and the upper abdomen were exposed, and the
patient was tilted slightly to the left before the anaesthetist inserted
and inflated a blocker into the right mainstem bronchus. Three ports
were inserted along the inframammary line and one port was inserted
through the anterior chest after deflation of the lung. The
pseudocapsule around the goiter was dissected free and the feeding
vessels were ligated. The goiter was then delivered via one of the
thoracic ports in an endopouch. The final histology demonstrated benign
nodular hyperplasia for both lesions.
Case
three
A 76-year-old female presented with right heart failure and pleural
effusion secondary to a retrosternal goiter in the anterior mediastinum
compressing upon the right heart, thus necessitating resection using a
transcervical-sternotomy approach (Figure 3a and 3b). A low
collar incision was made in continuity with the median sternotomy wound
which was carried down to the xiphoid process before sternal retraction
was applied (Figure 3c). The mediastinal component of the
goiter was mobilised and freed up to the aortic arch and multiple
feeding vessels from the mediastinum were ligated. The cervical
component was mobilised as described in case one. After full
mobilisation superiorly and identification of both recurrent laryngeal
nerves, the pleura was opened superiorly, and bilateral phrenic nerves
were identified. At this point, the retrosternal goiter was
progressively removed from the superior mediastinum en bloc with full
visualisation of both the recurrent laryngeal nerves and phrenic nerves(Figure 3d). On follow-up, the patient demonstrated normal
vocal cord movement bilaterally, intact parathyroid gland function, and
resolution of the symptoms from right heart failure. Her final histology
confirmed a multinodular goiter.
Case
four
A 68-year-old female with a history of retrosternal goiter treated with
iodine ten years prior presented with a large right-sided thyroid mass.
Fine needle aspiration suggested a diagnosis of papillary thyroid cancer
and her repeat CT scan confirmed an enlarged thyroid gland with cystic
retrosternal extension into the posterior mediastinum, adherent to
surrounding mediastinal structures. Total thyroidectomy was performed as
described in case one. The isthmus was divided, and the left lobe was
removed. Transcervical digital dissection of the retrosternal component
was performed as much as possible, and the right thyroid lobe was
pedicled on the retrosternal component (Figure 4a).
The remaining retrosternal component was removed with VATS. The goiter
was visualised in the posterior mediastinum and an incision was made on
the pleura (Figure 4b ). The azygous vein appeared adherent to
the goiter and was subsequently ligated with an Endo-GIA stapler. The
tumour was mobilised with endoscopic Ligasure. It was freed from the
trachea and continued circumferentially up to the level of the thoracic
inlet (Figure 4c). The goiter was subsequently delivered
through the neck, attached to the right hemithyroid (Figure
4d ). The patient had an uneventful recovery and was discharged on
postoperative day three. Final pathology confirmed a five-centimetre
papillary thyroid cancer with clear margins.
Discussion
Our
institutional algorithm firstly involves determining whether an
extracervical approach is warranted.
Approximately
95% of retrosternal goiters can be removed cervically through the neck
incision using upward traction, digital dissection, and with assistance
of long instruments (case one ).6 However,
some cases necessitate a concurrent extracervical approach
(Figure 1) . Adequate exposure is challenging with a cervical
approach in goiters extending below the aortic arch or carina or
situated within the posterior
mediastinum.7Similarly, an extracervical approach is necessary for vascular control
where the goiter has blood supply originating from mediastinal vessels
or for safe resection where no tissue plane between it and surrounding
tissues can be identified on CT.8 Finally, upward
traction in the cervical approach may be difficult in patients with
thyroid tissue beyond easy reach via the neck incision, isolated primary
or ectopic retrosternal goiters, or where the thoracic component
connects to the cervical component via a fibrous stalk (case
two ).9
Median sternotomy is the most common extracervical approach in the
literature. Whilst this provides excellent exposure to anteriorly
extending retrosternal goiters (case three ), it is associated
with considerable morbidity and exposure to the posteriorly extending
goiters remains limited by the heart and great vessels. Consequently,
the lateral thoracotomy is instead often used for posterior retrosternal
goiters due to better exposure and decreased
morbidity.4
VATS and mediastinoscopic approaches are increasingly used in the
treatment of retrosternal goiter (cases two and four ). In
comparison to open thoracotomy, VATS has been shown to be associated
with decreased postoperative pain, shorter hospital stay, improved
postoperative pulmonary function.10 In our experience,
these techniques may be utilised in cases where the retrosternal
component extends to the aortic arch, but the surgeon is unable to
obtain adequate vascular control for safe delivery of the lesion with
cervical blunt dissection. This is particularly valuable as the tissue
plane between the goiter and the pretracheal fascia, prevertebral fascia
and the oesophagus is often described as quite dense, with transcervical
approaches increasing the risk of inadvertent oesophageal tear or
uncontrollable bleeding.
Conclusion
Although
most retrosternal goiters can be removed transcervically, a small
proportion of patients require concurrent extracervical approaches.
Based on decades of experience in the surgical management of
retrosternal goiters, a practical institutional algorithm has been
presented to guide surgical planning in a complex field.