Total Thyroidectomy for Substernal Goiter 
Salem I. Noureldine, Mohamad Sidani, José Gabriel Paixão 
 
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Introduction:  
Thyroidectomy for a substernal goiter is 
typically a skill-demanding and complex procedure, 
yet very rewarding. The intricate neck anatomy is 
usually distorted in these cases, and often in an 
unpredictable pattern. Goiter size, shape, vascularity, 
distortion of anatomy, substernal extension, and 
restrictions imposed by the bones of the thoracic inlet 
can make thyroidectomy challenging, as well as 
recurrent laryngeal nerve (RLN) and parathyroid 
gland identification and preservation extremely 
difficult. That is why Halsted had said, “The 
extirpation of the thyroid gland for goiter better 
typifies perhaps than other operations, the supreme 
triumph of the surgeon's art.” 
This chapter is aimed at reviewing the 
patterns of anatomical distortion presented by 
substernal goiter, key points of preoperative 
evaluation, and treatment options with an emphasis 
on surgical approach.  
 
Definition and Classification 
There have been numerous definitions and 
classification schemes proposed for substernal goiter. 
They largely encompass the same definition; a goiter 
that is associated with a sub clavicular or substernal 
extension and therefore the thoracic component 
requires 
mediastinal 
dissection 
to 
facilitate 
extraction of the gland.  
 
Classification of substernal goiters. (A) Grade I: <25% 
substernal; (B) Grade II: 26% to 50% substernal; (C) Grade 
III: 51% to 75% substernal; (D) Grade IV: >75%. Adapted with 
permission from Cohen et al. Operative Techniques in 
Otolaryngology-Head and Neck Surgery, vol 5, No 2 (June), 
1994: pp 118-125 
 
Moreover, a classification system is most 
useful when it incorporates the features of the 
substernal 
goiter 
that 
must 
be 
appreciated 
preoperatively for safe extraction. Thus, axial cross-
sectional imaging to differentiate between the 
various subtypes is necessary. We emphasize that IV 
contrast should be avoided in these cases, as the 
iodinated contrast can lead to acute goiter 
enlargement and worsen compressive symptoms, 
necessitating at times airway protection and urgent 
surgical intervention.  
Total Thyroidectomy for Substernal Goiter 
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Substernal Goiter Classification - adapted from Randolph GW 
et al. Surgery of Cervical and Substernal Goiter. Surgery of the 
Thyroid and Parathyroid Glands – 2nd edition. Saunders 2013 
 
When the thyroid gland extends into the 
anterior mediastinum (Type I), it descends anterior 
to the subclavian and innominate vessels and anterior 
to the RLN. The normal and orthotopic relationship 
of an anteriorly descended mediastinal goiter to the 
RLN is therefore preserved (i.e., the nerve is deep to 
the gland.)  
 
Cross sectional computed tomography images of a patient with 
a large substernal goiter extending into the right mediastinum. 
The goiter descends anterior to the subclavian and innominate 
vessels and anterior to the RLN. (Substernal goiter type I) 
 
When the substernal goiter extends into the 
posterior mediastinum (Type II), it assumes a space 
posterior to the trachea, pushing the trachea 
anteriorly and splaying the great vessels anteriorly. 
The mediastinal extension of the gland then rests in 
the space posterior to the innominate and subclavian 
vessels, carotid sheath, RLN, and inferior thyroid 
artery. Therefore, the normal relationship of the 
thyroid gland and the RLN is reversed. The RLN 
becomes ventral to the inferior component of the 
thyroid and, if not recognized early on, can be 
stretched, or inadvertently cut. The nerve can also be 
entrapped between components of the posterior 
mediastinal goiter. This increased rate of RLN injury 
is 
well 
documented 
in 
series 
comparing 
thyroidectomy using only a cervical approach to 
sternotomy with mediastinal dissection to aid 
cervical removal. In those small series, there is a 
significantly decreased rate of RLN injury in patients 
who 
underwent 
sternotomy 
for 
mediastinal 
dissection.  
Posterior mediastinal goiters can come to rest 
in a space bounded inferiorly by the azygous vein, 
posteriorly by the vertebral column, laterally by the 
first rib, medially by the trachea and esophagus, and 
anteriorly by the carotid sheath, subclavian and 
innominate vessels, superior vena cava, and phrenic 
and RLNs. Therefore, it is important to be familiar 
with the regional anatomy of the lower neck and 
upper mediastinum.  
Posterior mediastinal goiters can occur on the 
same side as the enlarged lobe (Type IIA) or may 
come to rest through a retro-tracheal extension in the 
contralateral thorax (Type IIB.) Extension to the 
right mediastinum is more commonly seen because 
of the aortic arch and associated branch vessels 
blocking the left posterior mediastinal descent 
pathway. 
Contralateral 
posterior 
mediastinal 
extension may occur either behind the trachea and 
esophagus (Type IIB1) or between the trachea and 
esophagus (Type IIB2). Generally, the right 
mediastinal caudal extension is limited at the level of 
the azygous arch. 
Although rare, thyroid masses within the 
mediastinum may exist without connection to the 
normal cervical thyroid gland, known as an ectopic 
thyroid. Isolated mediastinal goiters are important to 
recognize because unlike all other types of substernal 
goiters, blood supply of the goiter may be through 
purely mediastinal arteries (i.e., aorta, subclavian, 
internal mammary, thyrocervical, and innominate) 
and veins. This is extremely important in planning 
their surgical resection. Also worth noting is that it is 
not uncommon for a goiter to be dumbbell shaped, 
when the substernal component is attached to the 
cervical component through a narrow thin band of 
Total Thyroidectomy for Substernal Goiter 
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thyroid parenchyma. Noting an ectopic thyroid goiter 
or a dumbbell shaped thyroid goiter preoperatively is 
crucial as complete resection is very difficult to 
achieve through a cervical approach only, even if the 
substernal component is not large or does not extend 
significantly into the mediastinum. 
 
Workup 
In the workup of patients presenting with a substernal 
goiter, 
the surgeon needs to systematically 
investigate all the following issues preoperatively: 
1. Existence of compressive symptoms such as: 
a.  Voice change or voice fatigue which 
could hint at an RLN already under 
excessive tension from displacement 
b. Dysphagia and regurgitation which could 
indicate significant mass effect on the 
esophagus, and the greater risk of an 
aspiration event upon induction of 
general anesthesia 
c. Airway compression, especially when the 
patient lies flat and is fully relaxed upon 
induction (i.e., loses most cervical muscle 
tone and the full weight of the goiter 
pushes down or further deviates the 
trachea). It is also important to realize that 
chronic mass effect of the goiter on the 
trachea results in tracheomalacia, and 
subsequently can leave the patient with a 
high risk of airway obstruction even post 
thyroidectomy.  
2. Risk of malignancy, especially if the portion of 
the 
thyroid 
that 
contains 
the 
suspected 
malignancy is substernal and not accessible for 
percutaneous needle biopsies to establish the 
diagnosis. 
3. Presence of hyperthyroidism, which would 
require medical therapy prior to thyroidectomy to 
achieve a euthyroid state and minimize the risk 
of a thyroid storm intraoperatively. Also, the risk 
of bleeding during thyroidectomy for a toxic 
thyroid goiter is slightly greater as they are 
commonly more vascularized than nontoxic 
goiters.  
4. Integrity of the RLN should be assessed either 
through ultrasound evaluation of the mobility 
and symmetry of the vocal cords (which can be 
challenging in patients with large goiters) or via 
direct visualization with nasolaryngeal fiberoptic 
endoscopy.  
5. Subtype of mediastinal extension (Table, above) 
and preoperative consultation with potential 
surgical planning by a thoracic surgeon, if 
available. The majority of substernal goiters will 
be resected through cervical approach. But there 
are a few characteristics that increase the risk for 
an extra-cervical approach: Malignant histology, 
Extension below the aortic arch’s convexity in 
the cranio-caudal plane and posterior extension 
to trachea in the anteroposterior plane.  
It is important, in limited-resource countries, that 
the surgeon be as independent as he/she can at 
imaging interpretation. 
 
Goiter physical examination: lateral and anterior view 
 
 
Find a "sulcus" between thyroid and sternum's manubrium, 
with mobile thyroid gland are a sign that there are minor or no 
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mediastinal extension. Thus, a cervical approach is more likely 
to succeed. 
 
 
As seen here, a widened mediastinum (on the right) and 
deviation of the trachea (towards the left) are indications that 
the airway is compromised and intubation may be more difficult.  
 
Indications 
It is generally agreed that thyroxine 
suppression therapy and radioactive iodine ablation 
are not acceptable interventions, and that surgery is 
the gold standard for substernal goiter management. 
Overall, these are the major indications for substernal 
thyroidectomy: 
1. Suspicion for or confirmed thyroid cancer 
2. Compression of adjacent organs 
3. Toxic multinodular goiter or toxic adenoma or 
thyrotoxicosis 
4. Cosmetic reasons 
 
Most surgeons would favor thyroidectomy 
even if asymptomatic, as substernal goiters will 
continue to grow over time and become more 
complex to resect when larger in size or extend 
further into the mediastinum. Moreover, the thoracic 
component of a substernal goiter poses difficulty for 
ongoing clinical examination or fine needle 
aspiration, as mentioned above. 
Surgery usually comprises two different 
approaches; one is completely transcervical, in 
which only a cervicotomy is performed, and the other 
requires an additional extracervical approach (e.g., 
thoracoscopically or via sternotomy.) Several 
different surgical techniques have been described; 
however, no clearly defined consensus exists on the 
indications for either approach to substernal thyroid 
goiter excision. 
 
A retrosternal goiter delivered through a trans-cervical 
approach. The dissection of the inferior part of the enlarged 
lobe was done with the surgeon’s finger, in the capsular plane 
of the thyroid.  
 
 
The completely removed specimen. The left lobe is 11cm in 
craniocaudal length, and more than half of that was inside the 
thoracic cavity, yet it could be removed through a trans-
cervical approach. 
 
Steps: 
Intubation 
Intubation is usually uneventful in patients 
with substernal goiters, but sometimes can be 
Total Thyroidectomy for Substernal Goiter 
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difficult, or even life-threatening, requiring an 
emergent and very challenging tracheotomy due to 
the overlying engorged goiter. A small portion of 
patients may also have evidence of substantial 
laryngeal deviation or vocal cord paralysis at 
intubation. A large substernal goiter can compress 
the venous drainage of the neck causing venous 
congestion that results in pharyngeal, laryngeal, and 
supraglottic soft tissue edema. Therefore, the 
surgeon and anesthesiologist should review all the 
preoperative data including cross sectional imaging 
and preoperative laryngoscopy and, examine the 
patient together before induction. The method of 
intubation, 
size 
of 
endotracheal 
tube, 
and 
contingency plans can be discussed and decided 
upon through these discussions.   
Typically, a straightforward induction with 
transoral intubation can be performed. Laryngeal 
deviation does not generally pose difficulty and a 
reasonably sized endotracheal tube can be used 
despite the extrinsic tracheal compression. A safe 
alternative method is an awake fiberoptic transoral or 
transnasal intubation with the patient in a full sitting 
position. Full knowledge and access to the 
maneuvers and instruments that can be employed for 
airway protection and better visualization of the 
vocal cords should be readily available.  Newer video 
laryngoscopes are also an excellent adjunct for 
intubation in such patients. Ultimately, to decrease 
the risk of laryngeal edema from intubation, it is best 
to intubate once correctly, as studies have shown that 
the larynx is easily made edematous with multiple 
unsuccessful intubation attempts. A useful maneuver, 
especially during awake intubations, is to grab the 
tongue with a dry gauze and pull it forward as much 
as the patient can tolerate. This will anteriorly 
displace the swollen laryngeal and supraglottic 
apparatus and improve cord visualization. “Armored” 
endotracheal tubes can be used for patients with 
significant tracheal compression distally. See also 
the chapter Airway Management and Endotracheal 
Intubation. 
 
Fiberoptic transoral intubation. The epiglottis is seen on the 
monitor. Note that the endotracheal tube is already on the 
fiberoptic scope: once the scope enters the trachea, this can be 
slid along the scope into position.  
 
Extent of Surgery 
The 
extent 
of 
surgery 
(i.e, 
hemithyroidectomy or total thyroidectomy) should 
be tailored to allow a favorable balance between the 
risk of operative complications and disease 
progression or recurrence. Complication rates must 
be kept extremely low in the setting of benign disease. 
Therefore, the minimum procedure should be a 
hemithyroidectomy, reserving bilateral surgery for 
significant bilateral goiter, malignant disease, or 
toxic multinodular goiter/ diffuse hyperthyroidism. 
Sometimes, when an ipsilateral nerve injury or an 
ipsilateral loss of nerve signal during intraoperative 
nerve monitoring occurs, the surgeon must change 
plans intraoperatively and possibly defer resecting 
the contralateral lobe. This helps avoid a potentially 
disastrous case of bilateral RLN injury requiring 
tracheostomy.  
 
Positioning 
Great emphasis should be placed on proper 
positioning of the patient on the operating room table. 
A shoulder roll should be placed under the patient’s 
shoulder blades as to extend the neck safely as much 
as possible with the head well supported. Additional 
extension may be obtained by placing the patient in 
a beach-chair mode position. 
 
Total Thyroidectomy for Substernal Goiter 
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Incision and Subcutaneous Flaps 
A generous collar incision is usually needed. 
Minimal access approaches are not appropriate for 
substernal goiter extrication. The traditional Kocher 
incision, extending to the lateral edge of the 
sternocleidomastoid (SCM) muscle, may be required 
for large bilateral goiters. 
 
A simple transverse collar incision is often sufficient. For very 
large glands, such as this one, the incision should be extended 
upwards along the anterior border of the sternocleidomastoid. 
Extending your incision further posteriorly does not help as 
much to improve access, and gives the appearance of a 
“decapitation.” 
 
A subplatysmal upper flap is developed all 
the way to at least the level of the cricoid cartilage; 
consider going to the level of the hyoid bone in 
especially large goiters. A generous lower flap is 
typically not necessary. Flaps can be sutured in place, 
or a self-retaining retractor can be used.  
 
The same incision, now with the flap elevated in the sub-
platysmal plane. Note the anterior jugular veins (Black arrows.) 
You will be dissecting along these, so proper technique is 
important to avoid troublesome bleeding.” Note also that this 
vein should be ligated if the “strap” muscles are divided, as 
described below.  
 
“Strap” Muscles 
Routine transverse sectioning of the strap 
muscles (sternohyoid and sternothyroid) during 
thyroidectomy for substernal goiter is not needed. 
Preserving the strap muscles allows preservation of 
the planes and anatomic organization of the central 
compartment and neck base that can be substantially 
altered by the goitrous change. However, if there is 
any question that strap division would improve 
mobilization, it should be done. Transverse 
sectioning of the strap muscles should occur at the 
top third of the muscle as the nerve innervation 
comes in caudal to cranial. The strap muscles can 
then be sutured back together at the completion of 
surgery with little adverse effect. The anterior jugular 
vein, running along the anterior surface of these 
muscles, may be sizeable in these patients and should 
be separately divided and ligated.  
 
Total Thyroidectomy for Substernal Goiter 
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Early Division of the Isthmus 
Early division of the thyroid at the isthmus, 
even in the setting of total thyroidectomy, facilitates 
better exposure, retraction and RLN identification in 
these cases. Dividing the isthmus early can allow for 
more medial mobilization of the thyroid lobe to 
facilitate exposure of the RLN as discussed later in 
this chapter. This might be more challenging when 
the most inferior aspect of the isthmus extends 
substernally along with the substernal component of 
the thyroid lobe. A key step to successfully perform 
this maneuver is to correctly identify the plane, using 
blunt dissection, above the cricothyroid muscle 
where its fibers meet along the cricoid cartilage and 
the isthmus. If the plane below the cricothyroid 
muscle is entered the dissection will be bloody and 
the risk of inadvertent penetration of the cricothyroid 
membrane or even trachea is more likely. 
 
Recurrent Laryngeal Nerve Identification and 
Preservation 
The most important rule to follow is that no 
structure is cut until the RLN is identified visually 
and, if nerve monitoring used, electrically. A 
bloodless field is essential for identification and 
preservation of the RLN. When operating on large 
goiters, this requires an especially careful technique. 
Once the inferior and superior poles are dissected, 
the strap muscles are retracted laterally and the 
thyroid, along with the trachea, should be retracted 
as one unit medially. This opens the lateral thyroid 
region. As the thyroid is dissected and freed from its 
lateral cervical attachments, it is progressively pulled 
medially and the airway itself is to some degree 
displaced upwardly and rotated through this 
retraction. This will expose the nerve at the RLN-
inferior thyroid artery crossing junction. Gentle blunt 
dissection helps in this maneuver. In this approach, 
the nerve is not uncovered inferiorly at the thoracic 
inlet. This approach helps to preserve parathyroid 
vascular 
supply, 
especially 
for 
the 
inferior 
parathyroid. Care must also be taken on the right side 
to identify a nonrecurrent right RLN. 
In certain cases of large goiters or in cases in 
which the tubercle of Zuckerkandl is well developed, 
the lateral thyroid region may not be adequately 
exposed to permit easy RLN identification. In such 
circumstances the nerve is best identified inferiorly. 
This involves identification of the RLN in the lateral 
aspect of the thoracic inlet on the right and in the 
paratracheal position at the thoracic inlet on the left. 
This relationship is shown in the photo below. 
Advantages of nerve identification at this location 
include the soft areolar bed in which the nerve lies in 
this region, allowing for atraumatic dissection. 
Another advantage of finding the nerve in the 
thoracic inlet is that the nerve here exists as one trunk 
before extra-laryngeal branching, which can occur 
above the inferior thyroid artery crossing point.  
 
Photo after removal of the thyroid gland shows the course of 
the right and left recurrent laryngeal nerves. The right nerve 
(Red arrow) courses around the right subclavian artery, which 
is very close to the area being dissected. Therefore, the nerve 
must take a more medial-to-lateral course to reach the larynx. 
The left nerve (White arrow) courses around the aortic arch, 
which is farther down in the chest and closer to the midline. It 
will therefore be taking a direction that is more straight cranio-
caudal.  
 
In some cases of large cervical or substernal 
goiters where the size and distortion of the anatomy 
make the lateral or inferior approach to identifying 
the RLN impractical, identifying the early nerve at 
the ligament of Berry-laryngeal entry point can be 
done. To facilitate this approach, early transection of 
the isthmus and initial dissection of the superior pole 
allow for lateral and caudal retraction of the superior 
pole to allow access to this segment of the nerve 
during the initial phases of lobectomy. The inferior 
Total Thyroidectomy for Substernal Goiter 
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cornu of the thyroid cartilage can be palpated to 
assist in nerve location in this area. The disadvantage 
of the RLN identification through this approach is 
that the dissection occurs at the ligament of Berry, 
which is fibrous and bleeds easily. Also, the nerve at 
this region may be branched. This approach is 
technically more challenging with large superior 
poles. The exposure of this superior pole region can 
be improved by division of the sternothyroid muscle, 
as described above. 
 
Parathyroid Preservation 
The distal inferior thyroid artery is divided 
after the RLN is identified and either before or after 
goiter delivery. The artery is ligated and divided 
directly on the thyroid capsule to reduce the risk of 
parathyroid ischemia. The superior parathyroid 
glands are more constant in position and are more 
frequently seen at thyroidectomy for goiter; therefore, 
they are more readily preserved. The inferior 
parathyroid gland is more variable in position and 
more likely to be significantly displaced by inferior 
pole goitrous change. Therefore, real emphasis 
during goiter surgery should be on superior 
parathyroid preservation. Inferiorly, strict adherence 
to capsular dissection to preserve displaced inferior 
parathyroid glands should be performed. Lastly, any 
resected thyroid specimen must be meticulously 
examined for capsular parathyroid glands before 
being sent to pathology. Any capsular parathyroid 
glands that are found should be dissected off, 
biopsied to confirm parathyroid tissue, and then 
auto-transplanted. Briefly, the parathyroid gland is 
cut into many tiny pieces with fine scissors or scalpel, 
and then placed within a surgically created “pocket” 
of adjacent muscle, usually the medial edge of the 
sternocleidomastoid. Recall that parathyroid glands 
may be found within folds and crevices of the goiter 
surface. 
 
Diagram showing the normal location of the parathyroid 
glands relative to a vertical line drawn through the axis of the 
recurrent laryngeal nerve, and a horizontal line drawn through 
the axis of the tubercle of Zuckerkandl, the posterior-most 
extent of the thyroid gland. The superior parathyroids, needing 
to migrate less distance, are more consistent in their location. 
The inferior parathyroids, having migrated farther and possibly 
being displaced by the goiter, are more likely to be in an 
abnormal position. Source: 
 http://www.endocrinesurgery.net.au, used with permission. 
 
Delivery of the Goiter from the Mediastinum 
After the RLN is identified and completely 
dissected away from the goiter, finger dissection in 
the capsular plane can allow for safe goiter delivery. 
The goiter is slowly mobilized upward out of the 
chest. Fascial band attachments as well as vascular 
pedicles are drawn up gently with the surgeon’s 
finger are cauterized or clamped only after the RLN 
location is completely identified along its entire 
course. Nerve monitoring can also be extremely 
helpful in this part of the procedure. Cysts within the 
thyroid, 
if 
benign, 
can 
be 
decompressed 
intraoperatively with a large bore needle to decrease 
the gland’s overall size.  
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A variety of instruments have been used to 
facilitate substernal goiter delivery. A mediastinal 
goiter “spoon” and a foley catheter placed in the 
mediastinum have both been described to assist in the 
delivery of substernal goiter without sternum 
division. If all these maneuvers are not effective, 
partial or complete sternotomy, or a thoracoscopic 
approach may be needed. It is important that the 
thyroid surgeon consults with their thoracic surgical 
colleagues and arrange the surgical date when a 
thoracic surgeon is available. 
 
Pitfalls 
• A complete preoperative workup is essential in 
treating 
patients 
with 
substernal 
goiters. 
Preoperative 
identification 
of 
substernal 
extension of the thyroid allows for appropriate 
preoperative imaging and surgical planning. 
Moreover, early identification of compressive 
symptoms or RLN dysfunction helps avoid 
perioperative complications. If CT scan is not 
available, 
careful 
physical 
examination 
supplemented by plain x-rays and ultrasound 
allows the surgeon to make a reasonable estimate 
of the extent of the substernal portion.  
• An anesthetist should review all the preoperative 
data to include cross sectional imaging and 
preoperative laryngoscopy and, examine the 
patient before induction. This ensures that the 
proper intubation technique and perioperative 
care will be administered.  
• Like routine thyroid surgery, the most important 
rule to follow is that no structure is cut until the 
RLN is identified visually and, if nerve 
monitoring used, electrically. A bloodless field is 
essential for identification and preservation of 
the RLN. The surgeon should be aware of the 
different techniques for RLN identification and 
preservation during these difficult cases. 
• Parathyroid identification and preservation is as 
important as RLN identification in these cases. 
Real emphasis should be placed on superior 
parathyroid 
preservation. 
Inferiorly, 
strict 
adherence to capsular dissection to preserve 
displaced inferior parathyroid glands should be 
performed. Any resected thyroid specimen must 
be 
meticulously 
examined 
for 
capsular 
parathyroid glands, which are then auto-
transplanted.  
• Preoperative surgical consultation with thoracic 
surgical colleagues, if available, is important and 
arrangements must be made so that proper 
intraoperative and postoperative care can be 
administered if the patient were to require 
sternotomy or thoracoscopy to assist with 
delivery of the substernal component. Further 
description of the sternotomy incision is in 
another Chapter of this Manual.  
 
Salem I. Noureldine MD 
George Washington University School of Medicine 
and Health Sciences 
Washington, DC, USA 
 
Mohamad Sidani MD 
Texas Tech University Health Sciences Center 
Lubbock, Texas, USA 
 
José Gabriel Paixão MD 
University Hospital João de Barros Barreto 
Belém, Pará, Brazil 
 
May 2023 
 
 
 
