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Thyroidectomy Procedures
MahmoudSakr
14
14.1 History
14.1.1 History ofConventional
Thyroidectomy
The earliest attempt at surgical treatment of goiter is present in the medical writings “Al Tasrif”
by the Moorish physician Ali Ibn Abbas or
Albucasis in about 952AD.He removed a large
goiter under sedation with opium with the use of
simple ligatures along with hot cautery irons as
the patient sat with a bag tied around his neck to
collect the blood from the wound [1]. In 1170, a
prominent surgeon, Roger Frugardii, at the
Salerno school performed a thyroidectomy using
setons, hot irons, ligaments, and caustic powders
[2]. In 1791, Pierre Joseph Desault achieved a
landmark in thyroid surgery by performing the
rst partial thyroidectomy [3]. However, Halsted
in his “The operative history of goiter” scrutinized procedures done before 1850 and analysed
them to be associated with 40% mortality [3, 4].
The high mortality was mainly due to hemorrhage, asphyxia due to tracheal compression,
hospital gangrene, and air embolism. These
drawbacks made even the most skilled surgeons
to avoid operating on goiters.
M. Sakr (*)
Department of Surgery, Faculty of Medicine,
Alexandria University, Alexandria, Egypt
Thyroid surgery started coming out of its doldrums in the middle of the nineteenth century due
to the concerted improvement in anesthesia,
infection prophylaxis and better hemostasis.
Albert Theodor Billroth, Austrian surgeon from
Vienna (1829–1894), is considered the most
skilled surgeon of the nineteenth century. In
between 1877 and 1881, he performed 48 thyroidectomies and was able to decrease the mortality to 8.3% [5].
Emil Theodor Kocher, Swiss surgeon from
Berne (1841–1917), is a pupil of Billroth and
Nobel Prize lauret in 1909. During his rst
10 years in Berne, Kocher had performed 101
thyroidectomies, with a mortality of 2.4%. By
1895, the mortality rate improved to about 1%.
He operated initially through an oblique incision
along the anterior border of sternomastoid or by a
vertical midline incision. The side effect of total
thyroidectomy (TT) in the form of “cretinoid
changes” was rst observed by Kocher, and he
called this “cachexia strumi priva”. He observed
that the patients would become sluggish, cold,
fat, and sometimes mentally deranged. At the age
of 76, in 1917, he presented the results of his
entire work at the Swiss Surgical Congress,
weeks before his demise. His presentation
revealed about 500 thyroid surgeries performed
by him with a mortality rate of 0.5% [5].
In 1891, Gley suggested that post- thyroidectomy
“tetany” is caused either by removal of the parathyroid glands (PTGs) or interference of the blood
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2024
M. Sakr (ed.), Head and Neck and Endocrine Surgery,
https://doi.org/10.1007/978-3-031-64102-2_14
t.me/Dr_Mouayyad_AlbtousH
405
406
M. Sakr
supply to these glands. The parathyroid blood supply was published in 1907 by Halsted and Evans.
They opined that “ultra-ligation” of the thyroid
arteries was to be practised, which was ligation
distal to the points of origin of the parathyroid
artery branches. They suggested avoiding inferior
thyroid artery (ITA) ligation [6]. Another serious
complication after TT was the recurrent laryngeal
nerve (RLN) injury. Mikulicz Radecki was particularly interested in preventing this complication
by preservation of the posterior aspect of the thyroid lobes [7].
Until the case of the lead opera singer Amelita
Galli-Curci, little attention was paid to the superior laryngeal nerves (SLNs) and their function.
She was operated for goiter in 1936 by Arnold
Kegel and G.Raphael Dunleavy. Several months
after recovery, the singer returned to the stage,
but her career was short-lived. She failed in her
upper range and could not sustain the notes with
apparent breathlessness during her performance.
The complication that happened to Amelita GalliCurci can now be recognized to be an injury to
the external branch of the SLN, which resulted in
cricothyroid muscle dysfunction which, in turn,
resulted in its inability to sustain maintenance of
tone of the vocal cords [7].
All these years, thyroidectomies were being
performed on nontoxic goiters as toxic ones were
considered poor candidates for surgery. Thus, toxic
goiters posed a new challenge for the surgeons. In
1923, Plummer published results of the 600 “thyrotoxic” patients that he had operated upon after
using Lugol’s iodine preoperatively. He demonstrated that the operative mortality rate dropped
from 4% to 1% by using Lugol’s iodine [8].
Further progress in the management of toxic
goiter happened with the introduction of radioac-
tive iodine (RAI) and its incorporation in therapeutics in 1942 by Means, Evans, and Hertz. A
year later, in 1943, came thiouracil, introduced by
Edwin Bennet Astwood. Beta-blockers (propranolol), developed about 20years later, were inducted
into the armamentarium for treatment of toxic
goiters in 1965. The incorporation of these drugs
contributed signicantly to the peri- operative
management of toxic goiter, the group of treatment: drugs, RAI, and surgery, still followed as
the basis of treatment for thyrotoxicosis [9].
With the development of imaging procedures
like ultrasound and computerised tomography
(CT) scanning, the diagnosis of goiter has become
even more precise. The introduction of neneedle aspiration cytology (FNAC) in 1952, as
described by Soderstorm, further improved the
diagnosis of goiter [10].
Along with advances in other disciplines of
medical science, viz., anesthesia, physiology and
radiology, surgical treatment of thyroid diseases
improved signicantly. The procedure became
safer with introduction of devices like the nerve
monitor for electro-identication of the RLN
intraoperatively. The transplantation of accidentally removed PTGs also gave a new hope in total
thyroidectomy surgeries.
Apart from making the surgery safe and effective, the quest started for newer techniques of
performing the procedure to achieve cosmetically better results and surpassing its other
drawbacks.
14.1.2 History ofMinimal Access
Thyroid Surgery
Garner etal., in 1996, generated much interest in
the eld of minimal access surgery after he
reported feasibility of endoscopic approach to the
PTGs [11]. Their focus then shifted to thyroid
surgery. The concept attracted the attention of
patients who appreciated the prospect of a better
cosmetic outcome, less hospital stay, and less
postoperative pain.
Over a short period of time, a number of techniques simultaneously started being called as
minimally invasive thyroid surgery (MITS).
These can be classied as pure endoscopic techniques, video-assisted techniques, and minimally
invasive open surgery.
Pure endoscopic technique differed in terms
of the different routes being used to approach the
thyroid compartment with or without carbon
dioxide gas insufation—the routes of access
being lateral neck [12], axilla [13], anterior chest
[14], and breast [15]. In all the routes, usage of a
30° endoscope is common.
Minimally invasive video-assisted thyroidectomy (MIVAT) was introduced and popularised by
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14 Thyroidectomy Procedures
407
an Italian team (Miccoli et al.) in the 1990s and
became the most widely used trechnique. In this
method, a 1.5-cm incision is made in the cervical
skin crease, through which the excised part is delivered after video-assisted excision of the gland.
Minimally invasive open surgical technique,
also termed “small incision thyroidectomy” does
not require specialized instruments. It differs
from the conventional surgery only in terms of its
length of incision, but with advantages galore
which includes decreased tissue trauma, less hospital stay, better cosmesis, less postoperative
pain, and increased postoperative comfort.
However, it has its disadvantages too—longer
surgical time, steep learning curve, and the
inated expenses of the surgery [16].
Till 2002, thyroid malignancies were considered unsuitable for endoscopic surgeries, but
then, Miccoli et al. [17] reported his series of
endoscopic surgery done in papillary thyroid
cancer (PTC) patients. They found MITS to be as
effective as conventional surgery in carefully
selected cases of PTC.Although there is not any
specic criteria for selection of cases, there seems
to be a consensus in terms of patient selection for
MITS, in terms of size of the tumor (<35mm in
case of benign ones and <20mm in case of malignant thyroid nodule/gland), with no history of
any previous surgery or irradiation, and no substernal or extra-thyroid spread in cases of PTC.
14.2 Surgical Anatomy
oftheThyroid Gland
14.2.1 Anatomical Site
A conical pyramidal lobe often ascends from
the isthmus or the adjacent part of either lobe
(more often the left) toward the thyroid cartilage,
to which it may be attached by a brous or bromuscular band, the “levator of the thyroid gland”.
Remnants of the thyroglossal duct may persist as
accessory nodules or cysts of thyroid tissue
between the isthmus and the foramen cecum of
the tongue base. Usually, two pairs of parathyroid
glands (PTGs) lie in proximity to the thyroid
gland.
14.2.2 Fascia andLigaments
The thyroid gland is enveloped by a brous capsule condensed from the pretracheal fascia. The
“anterior suspensory ligament” extends from the
superior-medial aspect of each thyroid lobe to the
cricoid and thyroid cartilages. The posteromedial aspect of the gland is attached to the side
of the cricoid cartilage, rst and second tracheal
rings, by the “posterior suspensory ligament”
(Berry’s ligament), which is responsible for
movement of the thyroid gland and related structures during swallowing. On its way to the larynx, the RLN usually passes deep to Berry’s
ligament or between the main ligament and its
lateral leaf [19].
Modern surgical resection of the thyroid
gland involves a “capsular dissection”.
Maintenance of the capsule helps reduce damage
to the plexus of veins that lie on its surface and
its highly vascular parenchyma. Additionally, it
reduces chance of injury to the adjacent neurovascular structures.
The thyroid gland is a brownish-red and highly
vascular endocrine gland located anteriorly in the
lower neck, extending from the level of the fth
cervical vertebra (C5) down to the rst thoracic
(T1). The normal gland weighs between 20 and
35g in adults and consists of two elongated lateral lobes with superior and inferior poles connected by a median isthmus overlying the second
to fourth tracheal rings. The superior poles extend
toward the oblique line of the thyroid cartilage,
lying deep to the sternothyroid muscle and supercial to the cricothyroid muscle [18].
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14.2.3 Relation withStrap Muscles
The lateral surface of the thyroid is covered by
the sternothyroid muscle, and its attachment to
the oblique line of the thyroid cartilage prevents
the superior pole from extending superiorly
under the thyrohyoid muscle. More anteriorly are
the sternohyoid and superior belly of omohyoid
muscle, overlapped inferiorly by the anterior border of the sternocleidomastoid (SCM) muscle.
The sternohyoid and sternothyroid muscles are
408
M. Sakr
joined in the midline by an avascular deep cervical fascia that must be incised to retract the strap
muscles laterally in order to access the thyroid
gland during thyroidectomy. Transection of strap
muscles, if necessary for better exposure, should
be done high in the neck because the motor nerve
supply from the “ansa cervicalis” enters these
muscles inferiorly. Supercial to these muscles
are the anterior jugular vein covered by platysma
and skin.
14.2.4 Arterial Supply
The arterial supply to the thyroid gland comes
from the superior and inferior thyroid arteries
and, occasionally, the thyroidea ima. These arteries have abundant collateral anastomoses with
each other, both ipsilaterally and contralaterally.
14.2.4.1 Superior Thyroid Artery (STA)
The superior thyroid artery (STA) arises as the rst
branch of the external carotid artery and passes in
a caudal direction to join the superior pole of the
thyroid. It has close relations to the external branch
of the superior laryngeal nerve (EB-SLN), which
lies deep to the artery before turning medially to
supply the cricothyroid muscle. High ligation of
the STA during thyroidectomy places this nerve at
risk of inadvertent injury, which would produce
dysphonia by altering pitch regulation. Thus, during thyroidectomy, the STA should be ligated as
close as possible to the thyroid gland to avoid
injury of the EB-SLN. “Joll’s triangle,” also known
as the “sterno-thyro- laryngeal triangle,” is used to
identify the location of EB-SLN during thyroid
surgery as it lies within this triangle. Joll’s triangle
is bounded laterally by the upper pole of thyroid
gland and superior thyroid vessels, superiorly by
the attachment of the strap muscles and deep
investing layer of fascia to the hyoid, and medially
by the midline. The oor of the triangle is made by
the cricothyroid muscle.
The STA has the following branches [20]:
– Infra-hyoid branch: it runs along the inferior
border of the hyoid bone.
– Superior laryngeal branch: it pierces the thy-
rohyoid membrane to enter the larynx.
– Sternomastoid branch: it runs backward
across the CCA to supply the SCM.
– Cricothyroid branch: it runs across the crico-
thyroid membrane to anastomose with the
artery of the opposite side.
– Anterior terminal branch: it runs downward in
front of the upper pole of thyroid gland.
– Posterior terminal branch: it runs downward
behind the upper pole of the thyroid gland.
– Parathyroid branch: it arises from the poste-
rior branch and passes to the superior PTG.
14.2.4.2 Inferior Thyroid Artery (ITA)
The inferior thyroid artery (ITA) arises from
thyrocervical trunk, a branch of the subclavian
artery, and passes in the trachea-esophageal
groove into the postero-lateral aspect of each
lobe. Most of its branches penetrate the posterior aspect of the lateral lobe. It has a variable
branching pattern and a variable relationship
with the RLN, most commonly passing in front
of the nerve and less commonly behind the
nerve.
To avoid injury of the RLN during thyroidectomy, the ITA should be ligated away from the
gland. However, this may jeopardize the vascular
supply to the PTGs, which are all supplied mainly
by the ITA.Thus, it is preferable that during thyroidectomy, the 2ry and 3ry and branches of the
ITA (not the main trunk) are ligated under vision
in order to preserve both, the RLN and blood supply to the parathyoids.
14.2.4.3 Thyroidea Ima Artery
The “thyroidea ima” is a single artery that arises
from the brachio-cephalic artery or the arch of
the aorta. It enters the thyroid gland at the inferior
border of the isthmus and is present in <10% of
patients, most commonly 3%.
14.2.4.4 Small Esophageal
andTracheal Branches
Small esophageal and tracheal branches supply
also the thyroid gland. They supply the thyroid
remnant after partial or subtotal thyroidectomy.
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14 Thyroidectomy Procedures
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14.2.5 Venous Drainage
Veins of the thyroid gland form a plexus of vessels lying in the substance and on the surface of
the gland. This plexus is drained by 3 pairs of
veins. The superior and middle thyroid veins
drain into the internal jugular vein (IJV). The
right inferior thyroid vein passes anterior to the
innominate artery to the right brachio-cephalic
vein or anterior to trachea to the left brachiocephalic vein. On the left side, drainage is directly
to the left brachiocephalic vein. Occasionally,
both inferior veins form a common trunk called
the “thyroid ima vein,” which empties into the
left brachiocephalic vein.
14.2.6 Lymphatics Drainage
Lymphatic drainage of the thyroid gland is extensive and ows multidirectionally, with intraglandular and subcapsular lymphatic drainage.
Immediate lymphatic drainage ows to the periglandular nodes, to the prelaryngeal (Delphian),
pretracheal, and para-tracheal nodes along the
RLN, and then to mediastinal lymph nodes (LNs).
Regional metastases of thyroid carcinoma can also
be found laterally, higher in the neck along the
IJV.This can be explained by tumor invasion of the
pretracheal and para-tracheal nodes causing an
obstruction of normal lymph ow. Often, the rst
LN involved in PTC is the Delphian LN, which is a
prelaryngeal node that lies just above the isthmus.
14.2.7 Innervation
Principal innervation of the thyroid gland derives
from the autonomic nervous system.
Parasympathetic bers come from the vagus
nerves, and sympathetic bers are distributed
from the superior, middle and inferior ganglia of
the sympathetic trunk. These small nerves enter
the gland along with the blood vessels. Autonomic
nervous regulation of the glandular secretion is
not clearly understood, but most of the effect is
postulated to be on blood vessels, hence the perfusion rates of the glands [21].
14.2.8 Nerves Related totheThyroid
Gland
The relationship of the thyroid gland to the
RLN and to EB-SLN is of major surgical signicance because damage to these nerves leads
to disability in phonation or to difculty
breathing. Both nerves are branches of the
vagus nerve.
14.2.8.1 Recurrent Laryngeal
Nerve (RLN)
The right RLN arises from the vagus nerve, loops
posteriorly around the subclavian artery, and
ascends behind the right lobe of the thyroid. It
enters the larynx behind the cricothyroid muscle
and the inferior cornu of the thyroid cartilage and
innervates all the intrinsic laryngeal muscles
except the cricothyroid. The left RLN comes
from the left vagus, loops posteriorly around the
arch of the aorta, and ascends in the tracheaesophageal groove (TEG) posterior to the left
lobe of the thyroid, where it enters the larynx and
innervates the musculature in a similar fashion as
the right nerve.
Several factors make the RLN vulnerable to
injury. The nerve is not always in the TEG where
it is expected to be. Medial traction of the lobe
often lifts the nerve anteriorly, thereby making
it more vulnerable. Likewise, ligation of this
artery, practiced by many surgeons, may be dangerous if the nerve is not identied rst.
Moreover, in the presence of large nodules, the
RLN may not be in their “regular” anatomic
location but may be found even anterior to the
thyroid gland. Finally, there may be a “nonrecurrent laryngeal nerve”, which occurs more on
the right side (0.6%) than on the left side
(0.04%) and is associated with vascular anomalies. Thus, the nerve is vulnerable to injury if it
is not visualized and traced up to the larynx during thyroidectomy (Fig. 14.1). The variable
relationship of the RLN to the ITA is another
factor (Fig.14.2).
Landmarks of the RLN: there is no substitute
for identication of the nerve in a gentle and
careful manner. The RLN can be found after it
emerges from the superior thoracic outlet, in
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410
ITA RLN ITA RLN
Vagus nerve
Vagus nerve
RLN
M. Sakr
Beahr’striangle bounded laterally by the common carotid artery, medially by the trachea, and
superiorly by the ITA [22]. Another hint to the
location of the RLN is the PTG location and
Zuckerkandl tubercle, an extension of the thyroid, close to the Berry’s ligament. On rare
occasions, the nerve may pass directly from the
vagus to the larynx, close to the superior thyroid
vessels [23].
14.2.8.2 External Branch
oftheSuperior Laryngeal
Nerve (EB-SLN)
The EB-SLN is important to the pitch of voice as
it innervates the cricothyroid muscle, the tensor
of the vocal cords. In most cases, this nerve lies
close to the vascular pedicle of the superior pole
of the thyroid lobes descending on the fascia of
the inferior pharyngeal constrictor. In some
patients, the EB-SLN lies on the anterior surface
of the thyroid lobe, making the possibility of
damage during thyroidectomy even greater. In
about 50% of cases, there is enough length
(>2cm) from the upper pole so that the STA can
be ligated safely with sparing of the
EB-SLN.However, in only 15% of patients is the
SLN sufciently distant from the superior pole
vessels to be protected from manipulation by the
surgeon. Unfortunately, many surgeons do not
even attempt to identify this nerve before ligation
of the upper pole vessels of the thyroid [24, 25].
14.3 Surgical Anatomy
oftheParathyroid Glands
14.3.1 Overview
The normal PTGs are 4in number and vary con-
Fig. 14.1 Identication and dissection of the recurrent
laryngeal nerve (RLN) along its whole course shown
intra-operatively (arrow)
Fig. 14.2 Anatomical relations between the recurrent laryngeal nerve (RLN) and inferior thyroid artery (ITA)
siderably in shape and size between individuals
and within the same individual. Usually they are
ovoid or bean-shaped but may be elongated, leaf-
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14 Thyroidectomy Procedures
411
like or multilobulated. Their diameter is variable,
although it should not be larger than 7mm, and
their individual weight ranges from 20 to 45mg.
The lower glands are usually larger than the
upper glands [26].
These 4 glands produce parathyroid hormone
(PTH), which helps to maintain calcium (Ca)
homeostasis by acting on the renal tubules and
Ca stores in the skeletal system, and by acting
indirectly on the gastrointestinal tract (GIT)
through the activation of vitamin D.Because of
their small size, their delicate blood supply, and
their usual anatomical position adjacent to the
thyroid gland, these glands are at risk of being
accidently removed, traumatized or devascularized during thyroidectomy leading to postthyroidectomy hypoparathyroidism and causing
hypocalcemia.
14.3.2 Recognizing theParathyroid
Glands
The PTGs have a distinct, encapsulated, smooth
surface that differs from the thyroid gland, which
has a more lobular surface, and LNs, which are
more pitted in appearance. The PTGs can be recognized by (1) their color (light brown to tan),
which relates to their fat content, vascularity, and
percentage of oxyphil cells within the glands
[27]; (2) their distinct hilar vessel (small vascular
pedicle), and (3) the fact that they bleed freely
when biopsy is performed, as opposed to the yellow fatty (adipose) tissue with their darkening
color of hematoma formation when they are traumatized. With experience, one becomes much
more capable of recognizing the PTGs, and of
differentiating them from either LNs or adipose
tissue. Frozen-section examination during sur-
gery can be helpful in their identication [27].
pharynx, accessory parathyroid fragments may
result and lead to super-numerary PTGs. They
are usually found at the level of the lower poles of
the thyroid or in the thymus. They can also be
found in the middle mediastinum at the level of
the aorto-pulmonary window or lateral to the
jugulo-carotid axis. On some occasions (5%), <4
PTGs can be present, even the complete absence
of PTGs is possible as in case of the genetic
abnormalities.
14.3.4 Location ofParathyroid
Glands
The superior PTGS glands migrate with the ultimobranchial body, while the inferior PTGS
migrate for a loner distance along with the thymus. It is very important to note that the location
of PTGs can vary, especially the site of the lower
glands.
14.3.4.1 Superior Parathyroid Glands
The superior PTGs are derived from the fourth pharyngeal pouch (PP) and migrate together with the
ultimobranchial bodies, which also develop from
the fourth PP, and, during the fth week of development, these cells detach from the pharyngeal wall
and fuse with the posterior aspect of the main body
of the thyroid as it descends into the neck. These
cells differentiate into the para- follicular cells
(C-cells) that secrete calcitonin [28].
The superior PTGs migrate a shorter distance
than the inferior glands, which results in a relatively more constant location in the neck. Because
the superior PTGs travel with the ultimobranchial
bodies, they remain in contact with the posterior
part of the middle third of the thyroid lobes. They
are most commonly found 1cm above the intersection of the ITA and the RLN, often just anterior to the RLN as it enters the larynx.
14.3.3 Number ofParathyroid
Glands
Usually 4 glands are present (90%); 2 on each
side, but >4 glands have been reported (5%).
When the pharyngeal pouches separate from the
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14.3.4.2 Inferior Parathyroid Glands
The inferiorPTGs arise from the dorsal part of
the third PP, along with the thymus, which
arises from the ventral part of the third PP.As
the inferior PTGs and the thymus migrate
together toward the mediastinum, they eventu-
412
M. Sakr
ally separate. Because they travel so far in
embryologic life, the inferior PTGs have a
more variable location than the superior PTGs.
In most cases, the inferior PTGs become localized on the lateral or posterior surface of the
inferior poles of the thyroid, and the thymus
continues to migrate toward the mediastinum
[29]. The wide range of distribution of the inferior PTGs in adults extends from just beneath
the mandible to the anterior mediastinum. They
may be found above, or within several centimeters of the lower thyroid pole within the thymic tongue [29].
14.3.4.3 Natural Variation inLocation/
Ectopic Glands
Superior PTG Variations
The superior PTG migration patterns extend to
the retropharyngeal, retrolaryngeal, retro-
esophageal, and posterior mediastinum [30].
Rarely (0.5–4%), PTGs may be ectopically
located within the thyroid gland itself [31–34].
An intra- thyroid PTG is dened as being “completely surrounded on all sides by thyroid tissue.” This intra-thyroid localization occurs most
likely embryologically due to superior PTG
fusion with the ultimobranchial bodies during
development.
Inferior PTG Variations
The location of the inferior PTGs exhibits a
greater degree of variability than the superior
PTGs. This is due to their migration with the
thymus, which descends from the angle of the
mandible to the pericardium. Thus, ectopic inferior PTGs can lie anywhere along this path of
descent, including the carotid sheath.
Approximately, 61% of the inferior PTGs are
found inferior, lateral, or posterior to the lower
pole of the thyroid gland [35]. The inferior
PTGs may be also intra- thyroidal and may also
commonly be found in the thyro-thymic tract or
the cervical portion of the thyroid [36]. If the
inferior PTGs fail to separate or separation from
the thymus is delayed during their descent, the
inferior glands may have ectopic locations
within the superior mediastinum.
Super-Numerary PTG Location
The super-numerary PTGs are usually found at
the level of the lower poles of the thyroid or in the
thymus. They can also be found in the middle
mediastinum at the level of the aorto-pulmonary
window, or lateral to the jugulo-carotid axis [36].
14.3.5 Arterial Supply
14.3.5.1 Superior Parathyroid Glands
The superior PTG is also usually supplied by the
ITA or by an anastomotic branch between the
ITA and STA. Several studies showed that in
20–45% of cases, the superior PTGs receive signicant vascularity from the STA, usually in the
form of a small parathyroid artery from the posterior branch of STA, given off at the level of the
superior pole of the thyroid [20, 37, 38].
14.3.5.2 Inferior Parathyroid Glands
The inferior PTGs are supplied by the ITA from
the thyrocervical trunk. Thus, it is preferable that
during thyroidectomy, the 2ry and 3ry branches of
the ITA (not the main trunk) are ligated under
vision in order to preserve not only the RLN, but
also the blood supply to the parathyoids. Studies
have shown that in approximately 10% of
patients, the ITA is absent, most commonly on
the left side. In these cases, a branch from the
superior thyroid artery (STA) supplies the inferior PTG [39].
Inferior PTGs that descend into the anterior
mediastinum are usually vascularized by the
ITA.If a PTG is positioned low in the mediastinum, it may be supplied by a thymic branch of
the internal thoracic (mammary) artery or even a
direct branch of the aortic arch [31].
14.3.6 Venous andLymphatic
Drainage
The inferior, middle, and superior thyroid veins,
which drain the parathyroid glands (PTGs),
empty into the IJV or the innominate vein [26].
Lymphatic drainage of the PTGs is similar to
that of the thyroid gland, with lymph vessels
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14 Thyroidectomy Procedures
413
draining into the deep cervical LNs and paratracheal LNs [40].
14.3.7 Innervation
The innervation of the PTGs is either direct from
the superior or middle cervical ganglia or through
a plexus in the fascia on the posterior lobar
aspects [41].
14.4 Indications
ofThyroidectomy
Thyroidectomy is one of the most commonly
performed operations in general surgery. It is
considered a safe procedure with low morbidity
and very low mortality [42].
14.4.1 Absolute andRelative
Indications
diseases. Currently, however, an increasing number of TTs are performed in specialist endocrine
surgery units, and the indications include MNG
and Graves’ disease. This policy proved to eliminate all abnormal tissues in the neck including
micro-carcinomas and lower recurrence rates
[46–50]. In addition, TT eliminates the source of
the Graves’ disease auto-antibodies and alleviates any associated endocrine ophthalmopathy in
80–85% of patients.
After TT, hormone replacement with
L-thyroxin is relatively easy and can be achieved
by monitoring the thyroid hormone serum levels.
As a result, TT is currently regarded as the surgical procedure of choice to treat Graves’ disease
and MNG [51], particularly that the reported risk
of postoperative complications of the RLN and
PTGs in specialized units is equivalent for total,
subtotal, and hemi-thyroidectomy [51–54].
14.5 Conventional (Open)
Thyroidectomy
Absolute indications of thyroidectomy include
(1) compression of the trachea and (2) malignancy or suspicion of malignancy. Relative indi-
cations include (1) nodular toxic goiter, (2)
failure of antithyroid drugs (ATD) in treatment of
thyrotoxicosis due to resistance, relapses, or
reactions, (3) thyrotoxicosis in the young under
45years of age, (4) social and economic factors
when the patient is unable or unwilling to undergo
long-term supervision with medical treatment,
and (5) intra-thoracic goiter [43].
14.4.2 Total Thyroidectomy (TT)
forBenign Disorders
The use of TT remains controversial for small
differentiated thyroid carcinomas, but even more
controversial is its use to treat benign diseases
[44, 45]. Most surgeons avoid the procedure
owing to the possible complications such as permanent RLN palsy and permanent hypoparathyroidism; subtotal thyroidectomy has thus
been the preferred operation for benign thyroid
Conventional thyroidectomy has many advantages. There is no need to divide any muscle,
except the platysma. This operation has a high
success rate with negligible operative mortality
and morbidity rate. Most of the procedures can
be carried out through cervical incisions of
4–6cm in length, in <90 min, with an excellent
cosmetic result.
14.5.1 Surgical Technique
Thyroid operations should be performed in a
blood-free eld so that vital structures can be
identied. Operating telescopes (magnication:
2.5× or 3.5×) are also recommended because
they make it easier to identify the normal parathyroid glands (PTGs) and the RLN.If bleeding
occurs, pressure should be applied. The vessels
should be clamped only if they are precisely
identied, and the RLN has been identied [55].
As a rule, dissection should always be done
rst on the side where the suspected tumor is; if
there is a problem with the dissection on this side,
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414
M. Sakr
Fig. 14.3 Thyroidectomy incision in the skin crease,
1cm below the cricoid cartilage
a less than total thyroidectomy can be performed
on the contralateral side to prevent complications.
There is, however, one exception to this rule: if
the tumor is very extensive, the surgeon will
sometimes nd it easier to do the dissection on the
easier side rst to facilitate orientation with
respect to the trachea and the esophagus [55, 56].
14.5.1.1 Skin Incision
A Kocher transverse incision paralleling the normal skin lines of the neck is made 1cm caudal to
the cricoid cartilage (Fig. 14.3). This locates it
precisely over the isthmus. As a rule, the incision
should be about 4–6cm long, extending from the
anterior border of one SCM muscle to that of the
other and passing through the platysma [57]. The
length of the incision should be modied as necessary for good exposure.
Patients with short, thick necks, low-lying
thyroid glands, or large thyroid tumors require
longer incisions than those with long, thin necks,
and small tumors. A sterile marking pen should
be used to mark the midline of the neck (the level
at which the incision is made) and the lateral margins of the incision (which should be at equal distances from the midline so that the incision will
be symmetrical) [58].
The upper ap is dissected rst by placing
three Alice forceps on the dermis and retracting
anteriorly and superiorly. This blood-free plane is
deep to the platysma and supercial to the anterior jugular veins. Cephalic dissection can be
Fig. 14.4 Midline incision and separation of the strap
muscles
done quickly with the electro-cautery or a scalpel, and lateral dissection can be done bluntly.
The same principles are applied to dissection of
the lower ap. In thin patients, the surgeon must
be careful not to dissect through the skin from
within, especially at the level of the thyroid cartilage [57, 59].
14.5.1.2 Dissection ofStrap Muscles
The thyroid gland is exposed via a midline incision through the supercial layer of deep cervical
fascia between the strap muscles. Because the
strap muscles are farthest apart just above the
suprasternal notch, the incision is begun at the
notch and extended to the thyroid cartilage [59,
60] (Fig.14.4). The sterno-thyroid muscle is then
dissected free from the thyroid and the prethyroidal fascia by blunt or sharp dissection until the
middle thyroid vein or veins are encountered laterally [61, 62].
The thyroid is retracted anteriorly and medially and the carotid sheath laterally; this retraction places tension on the middle thyroid veins
and helps expose the area postero-lateral to the
thyroid where the PTGs and the RLNs are situated. The middle thyroid veins are divided to give
better exposure behind the superior part of the
thyroid lobe [63, 64] (Fig.14.5).
As a rule, it is not necessary to divide the strap
muscles; however, if they are adherent to the
underlying thyroid tumor, the portion of the muscle that is adhering to the tumor should be sacriced and allowed to remain attached to the
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