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160
ENDOCRINE SURGERY
substantial, making this an unappealing option
for many patients. Single-agent regimens using
doxorubicin, dacarbazine, capecitabine, and
5-fluorouracil have been reported with partial
response rates up to 24–29% [30]. Newer chemotherapeutic agents, such as Irinotecan (a
topoisomerase I inhibitor) and 17-AAG (heat
shock protein 90 inhibitor), are currently
being evaluated in phase II clinical trials.
Patients with metastatic disease can have significant symptoms from calcitonin excess
including severe flushing, diarrhea, and weight
loss. Patients with hormonal symptoms may
benefit from medical treatment with somatostatin analogs. These patients may also benefit from
cytoreductive surgery of unresectable disease.
Procedures to decrease the tumor burden,
including resection and ablation, may provide
patients with significant symptomatic relief [27].
With the discovery of the RET protooncogene and its integral role in the pathogenesis
of MTC, a new class of therapies have developed
aimed at the molecular pathways central to the
development and progression of MTC. RET is
part of the receptor tyrosine kinase family. RET
has been shown to signal through multiple
downstream pathways including ERK, PI3K/
AKT, p38 MAPK, and JNK [4]. While present
investigations and therapies aim to block the
tyrosine kinase at the receptor level, there is
significant potential for developing more
focused therapies as we gain a better understanding of the critical downstream targets of
these receptors.
Recently, a new class of drugs has been discovered that act as tyrosine kinase inhibitors.
The first commercially available receptor tyrosine kinase inhibitor was imatinib mesylate
(Gleevec), which has been used successfully in
the treatment of chronic myelogenous leukemia
and gastrointestinal stromal tumors. An initial
phase II study with Gleevac in MTC has shown
limited efficacy with no responses in 15 patients
and significant toxicity [31].
Many of the tyrosine kinase inhibitors thatare
now being investigated inhibit multiple receptors, including RET, EGFR, andVEGF. A tyrosine
kinase inhibitor that show significant inhibition
of the RET receptor tyrosine kinase has been
identified and is currently in phase II clinical
trials. This drug, initially labeled ZD6474 and
now referred to as Vandetanib (Zactima), is
available in an oral form and has been shown to
have efficacy in inhibiting the RET receptor.
Vandetanib is currently being evaluated in a
multicenter phase II clinical trial for patients
with hereditary MTC. Preliminary results have
been presented inabstract form and reveal a 20%
partial response and a 30% stable response by CT
imaging [32]. However, there was a much more
dramatic decrease in tumor markers. Plans are
underway to expand this trial to sporadic MTC
as well.
Several other receptor kinase inhibitors are
also undergoing evaluations in clinical trials,
many of these trials have not been published but
preliminary results have been presented and
there appears to be some efficacy in patients
with metastatic MTC. Motesanib diphosphate
(AMG 706) is a multikinase inhibitor that is currently in phase II clinical trials. AMG 706 targets
VEGF, PDGF, RET, and Kit receptors. It is currently being evaluated in both advanced differentiated thyroid cancer and advanced MTC. Results
from the MTC portion of the trial are not available yet, but some antitumor activity was seen in
patients with differentiated cancer [33]. Sorafenib
(BAY 43-9006), another RET kinase inhibitor
currently in phase II trials, has been shown to
cause a dramatic reduction in calcitonin levels
and leads to marked symptomatic improvement
in patients with metastatic disease. In addition,
no patient on Sorafenib had progression of disease [34]. Interestingly, many of these new therapies lead to dramatic reductions in calcitonin
levels almost immediately, suggesting that
tumor markers may not be a reliable way to
monitor tumor response to therapy.
Future Therapies
Many of these tyrosine kinase inhibitors lack
receptor specificity, therefore their true mechanism ofaction is not clearly known. Severalsignaling pathways, such as the phosphatidyl-inositol
3-kinase (PI3K)/Akt, mitogen-activated protein
kinases (MAPKs), and Notch1/Hairy Enhancer
of Split-1 (HES-1)/achaete-scute complex like-1
(ASCL1) signaling pathway, have also been
shown to play important roles in regulating the
growth of neuroendocrine tumors (NETs)[35–39]
Thus, another potential therapeutic target could
be manipulation of these various cellular signaling
pathways.
Notch1 signaling is very minimal or absent in
prostate cancer, and NETs such as small cell lung
161
MEDULLARY THYROID CANCER
cancer (SCLC), carcinoid, and MTC [35, 36, 40,
41]. Activation of Notch1 significantly reduced
the growth of MTC (TT) cells and regulates calcitonin levels in a dose-dependent manner.
These observations support the hypothesis that
Notch1 functions as a tumor suppressor in MTC
tumors and cell lines. Recently, we and others
have reported that Raf-1 activation in a
MTC(TT) cell line results in growth suppression
as well as reduction in NE hormones (such as
calcitonin and serotonin) and levels of the RET
protooncogene [42, 43, 39]. We have explored
the possibility of pharmacologically activating
raf-1 in MTC cells. Though the compound
ZM336372 was originally identified as a small
molecule inhibitor of Raf-1 [44], recently we
have shown that it activates raf-1 pathway in
NET[37,45].Recentlywehaveobservedthat
treatment of MTC cells with ZM336372 resulted
in growth inhibition suggesting that activation of
raf-1 pathway is required for the antitumor proliferation effect (Kunnimalaiyaan et al., manuscript in submission). Given the important role
of Notch1 and raf-1 in the regulation of growth of
MTC, we hope that activating compounds for
these signaling pathways will have novel and
potent therapeutic value for the treatment of
patients with MTC.
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12
Technique of Thyroidectomy
He´le`ne Gibelin, Thibault Desurmont,
and Jean-Louis Kraimps
Introduction
Thyroid surgery is the most common operation
in endocrine surgery. Total extracapsular
lobectomy with isthmusectomy (isthmolobectomy) is the procedure of choice. The entire lobe
and the isthmus, including the pyramidal lobe,
must be removed.
Subtotal lobectomy should be avoided since
reoperation to complete a lobectomy is associated with a greater risk of injury to the recurrent laryngeal nerve (RLN) and parathyroid
glands. Consequently, subtotal lobectomy is considered an inadequate operation. Thyroid surgery can and should be a safe procedure with
minimal morbidity and negligible mortality. An
accurately performed operation on thyroid gland
requires both experience and technical ability
[1, 2]. This emphasizes the importance of skilled
Departments in Endocrine Surgery, performing a
great number of procedures and teaching the
youngest surgeons and residents [3]. It is the
best way to minimize incidence of complications.
The general rules of thyroid operation are as
follows:
Good exposure (by conventional approach
or with the endoscope in mini-invasive
approaches). Excellent visualization is the
main way to avoid RLN or parathyroid
injury.
Systematic identification of anatomic struc-
tures and meticulous dissection [4]. Thyroid
operation without identification RLN or
parathyroid glands does not make sense.
Consequently, bleeding should be avoided;
if the latter occurs, identification of these
anatomic structures is absolutely required
before hemostasis avoiding diathermy, even
bipolar.
Before surgery, the patient should be
informed about the reasons why an operation is needed, the alternative methods of
treatment that might be used, and the potential risks and benefits of the procedure.
Information about possible complications
must be given to the patient and clearly
explained before surgery.
The patient should undergo a thorough medical evaluation to be sure that he or she is
euthyroid.
Isthmolobectomy
The patient is carefully positioned on the operating table with the neck hyperextended. A rolled
towel is placed under the shoulders which allows
sufficient neck extension. A sponge ring isplaced
under the occiput for adequate head support and
to keep it from moving. The eyes should be carefully taped shut to avoid corneal abrasions.
Disinfection is performed with an alcoholic
agent without iodine, which might interfere
with postoperative radionuclear scanning and
ablative therapy.
J.G.H. Hubbard et al. (eds.), Endocrine Surgery, Springer Specialist Surgery Series,
DOI 10.1007/978-1-84628-881-4_12, Ó Springer-Verlag London Limited 2009
163
164
ENDOCRINE SURGERY
Slight elevation of the head of the operating
table is helpful in decreasing venous congestion.
The surgical field is draped from below the
sternal notch to the chin and laterally on posterior part of the sternocleidomastoid muscles.
Skin Incision
The standard Kocher’s incision must be used. It
is a collar-type incision placed transversally
along the Langer’s line of the skin. This yields
an excellent cosmetic result. The length of the
incision must be adapted to the thyroid size.
Most often a 4- to 5-cm incision allows safe
thyroidectomy, but a larger incision can be
necessary in case of large goiters or short neck.
The surgical incision should therefore be made
about 1 cm caudal to the cricothyroid cartilage
since it then will be centered directly over the
thyroid gland.
The skin incision should be made perpendicular to the patient and carried down
through the subcutaneous tissue and platysma
muscle with preservation of the anterior jugular veins.
The skin, subcutaneous fat, and platysma
muscle should be mobilized as two flaps upward
to the thyroid cartilage and downward to the
sternal border (see Fig. 12.1). Once these flaps
have been mobilized, skin towels are applied, as
well as a self-retaining retractor.
Strap Muscles
The next step is the dissection in the midline of
the neck between the strap muscles from the
thyroid cartilage to the suprasternal notch.
Sternohyoid and sternothyroid muscles are dissected and retracted using right-angle retractors.
The middle thyroid vein is identified, ligatured,
Fig. 12.1. Mobilization of superior flap preserving the anterior jugular veins.
165
TECHNIQUE OF THYROIDECTOMY
and divided. Division of the strap muscles is
rarely necessary in case of very large goiter or
in reoperative cases.
Upper Pole
Lateral retraction using forceps allows the
opening of the space between the lobe and the
cricothyroid muscle, thus often exposing
the external branch of the superior laryngeal
nerve [5–7]. The external branch of the superior laryngeal innervates the cricothyroid muscle, the action of which is to increase the
tension of the vocal cords. Injury can lead to
an inability to achieve high notes during singing or speaking. Furthermore, in about 15% of
patients, the nerve accompanies the superior
thyroid artery. The best way to avoid injury of
this nerve is to open the space between thyroid
lobe and cricothyroid muscle, to stay lateral to
this muscle and to ligate and divide only
the superior thyroid artery branches (see
Fig. 12.2).
The complete division of the superior vessels enables the surgeon to medially rotate and
anteriorly mobilize the gland, which results in
optimal exposure of superior parathyroid
gland and RLN. In some cases, the posterior
branch of the superior thyroid artery can be
preserved for superior parathyroid gland
supply.
Lower Pole
The inferior thyroid veins can be safely ligated
and the trachea observed, allowing a better
medial rotation of the lobe with a better exposure of the hilum of the gland.
Lateral Dissection
Lateral retraction of the carotid sheath and medial rotation of the thyroid lobe allows tension of
the inferior thyroid artery and makes the RLN
easier to identify, most often crossing under or
occasionally over the inferior thyroid artery. At
this step, RLN must be identified. A small vessel,
the vasonervorum, is always observed on this
nerve, confirming identification.
Dissection should be meticulous, with the
aim of preserving as much of the inferior thyroid artery and its branches as possible, since it
supplies the blood to the two parathyroid
glands. Truncal ligation of inferior thyroid
artery results most often in parathyroid necrosis
and should not be done.
Dissection is carried out between the thyroid
capsule and the last branches of the inferior thyroid artery [8, 9]. The branches are ligated or
clipped individually directly on the surface of the
thyroid gland. Dissection is continued from the
bottom to the top, preserving parathyroid glands
with their blood supply and RLN (see Fig. 12.3).
Fig. 12.2. Dissection of the upper pole. Elective division of the
superior thyroid artery. (1) Inter crico-thyroid space; (2) superior thyroid artery; and (3), left upper pole of the thyroid.
Fig. 12.3. Left superior parathyroid gland. (1) Left recurrent
laryngeal nerve and (2) left superior parathyroid gland.
166
ENDOCRINE SURGERY
Fig. 12.4. Left Berry ligament dissection. (1) Left thyroid lobe;
(2) trachea; and (3) left recurrent laryngeal nerve.
At the upper part of the dissection, the RLN
is very close to the thyroid at the site of the
ligament of Berry, just before the nerve enters
to the cricoid muscle. It is at this site of the
ligament of Berry that the RLN is the most
vulnerable to injury [10] (see Fig. 12.4). The
ligament of Berry is a dense group of vessels
and connective tissue that attaches the thyroid
to the trachea. Small vessels are often situated in
it, posterior to the nerve and bleeding is particularly dangerous in this site (see Fig. 12.5).
Positive identification of the nerve must be
made prior to ligature. The use of any cautery
or other thermal dissection device should be
avoided at this step due to the potential for
Fig. 12.5. Left Berry ligament dissection. (1) Insertion of
posterior part of left thyroid lobe at the Berry ligament;
(2), trachea; and (3) left recurrent laryngeal nerve.
Fig. 12.6. View after left thyroid lobe resection. (1) Trachea;
(2) left recurrent laryngeal nerve; and (3) left superior parathyroid gland.
thermal injury of the RLN, which is in close
proximity (see Fig. 12.6).
After this step, the thyroid lobe may be
quickly dissected free from the trachea. Near
the midline, one should look for a pyramidal
lobe, which is present in about 80% of individuals and should be removed with the thyroid
lobe.
Parathyroid Autotransplantation
Even in unilateral lobectomy, all identified
parathyroid tissue should be preserved on its
native blood supply. If a gland is devascularized
during dissection, it should be transplanted
[11]. Furthermore, it is sometimes impossible
to preserve a parathyroid gland since it is under
the thyroid capsulae.
It is recommended to systematically look at
the parathyroid glands at the end of operation
before closure. The gland can be congestive
because of lack of veinous drainage. In this
case, the parathyroid capsulae must be incised,
and in a few seconds, the gland will recover a
nice color.
Sometimes the gland is devascularized and
autotransplantation is necessary. In this case,
the gland is removed and cut into tiny cubes
that are about 1 mm
created by separating the muscle fibers of the
sternocleidothyroid muscle, avoiding any
bleeding. It is important to avoid bleeding
since hematoma formation could compromise
3
in volume. A pocket is
167
TECHNIQUE OF THYROIDECTOMY
ab
Fig. 12.7. (a and b) Closure.
the parathyroid function of the graft. The
minced tissue is then transplanted into the
pocket, which is closed by titanium clip or nonabsorbable suture as landmark.
Wound Closure
A drain is necessary only if a very large goiter
has been removed with a large persisting space
and can never replace accurate hemostasis. It is
of little or no use if severe postoperative bleeding occurs [12, 13].
The sternothyroid and sternohyoid muscles
are sutured on the midline, as the platysma with
4-0 absorbable suture. The skin is closed by an
intradermal 5-0 absorbable suture. In addition,
glue can also be used on the skin (see Fig. 12.7).
Reoperative Thyroid Surgery
The best approach is the identification of RLN
in a previously undissected area.
A lateral or ‘‘back door’’ approach is recommended in case of reoperation. After standard
collar incision, the anterior border of the sternocleidomastoid muscle is mobilized and
retracted laterally to expose sternohyoid and
sternothyroid muscles. The lateral border of
the sternothyroid muscle, inferior to the omohyoid muscle, is mobilized off of the carotid
artery and jugular vein. With a retractor, the
sternothyroid muscle is reflected medially and
the carotid artery laterally. The soft tissue at the
inferolateral part of the thyroid lobe is exposed
and can be dissected. Dissection is performed in
a straightforward manner with, first, identification of the RLN, then control of inferior pedicle,
and then superior pedicle.
A second approach is to enter the thyroid bed
similarly to the initial operation. Then one can
choose either an inferior approach and search
for the RLN in the paratracheal region inferior
to the area of previous dissection or a superior
approach to identify the RLN where it enters the
larynx.
Substernal Goiter
Most intrathoracic goiters can be removed
though a standard collar incision. A sternotomy
is required in less than 10% of cases. In case of
bilateral intrathoracic goiter, we recommend
commencing the resection on the smaller side
and in some cases dividing the isthmus. For
intrathoracic goiter, we prefer the toboggan
technique described by Charles Proye: the goiter
should be mobilized from top to bottom. The
first step is to divide and ligate the superior
thyroid artery and veins with preservation of
the superior parathyroid gland. Section of the
head of the sternocleidomastoid muscle or of
the straps muscles (sternothyroid or sternohyoid muscles) may help in some cases. The
second step is to control middle thyroid veins
and mobilise the lateral part of the lobe. It is
necessary to identify the position of the RLN
before trying to mobilize the intrathoracic part
of the lobe. It is often easier to identify the nerve
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ENDOCRINE SURGERY
close to the inferior horn of the thyroid cartilage
where it enters the larynx and then to follow it
caudally. The pedicle posterior to the nerve can
then be controlled, and a space of dissection
opened between the nerve and the posterior
part of the thyroid. A finger is placed in cervicothoracic space, following the posterior part of
the lobe. During this dissection, it is possible to
control the location of the nerve in relation to
the goiter. Adhesions surrounding the lobe are
progressively liberated. With gentle traction on
the thyroid lobe, to avoid fragmentation of the
thyroid, it is progressively exteriorized with control of the inferior thyroid vessels. When the
entire lobe is extracted, it is important to check
the absence of the inferior parathyroid gland at
the posterolateral surface of the lobe. When a
parathyroid gland is devascularized, it should
be autotransplanted in the sternocleidomastoid
muscle before the end of the procedure. The
insertion of a closed suction drain is recommended because of the large remaining mediastinal cavity.
Local or Regional Anesthesia
Local or regional anesthesia represents a safe
alternative to general anesthesia in patients
with amiodarone-induced thyrotoxicosis [14].
A regional C2-C4 superficial cervical and local
field block is performed using a mixture of 0.5%
lidocaine and 0.25% bupivacaine. To avoid
excessive traction on the muscles, the skin incision is higher on the neck, just inferior to the
cricoid cartilage prominence.
intubation dose is recommended [17]. During
the dissection, either the RLN or vagus nerve
should be stimulated. A positive acoustic signal
after stimulation of both the vagus nerve andthe
RLN is an indication that the nerve conduction
between the place of stimulation and the vocalis
muscle is intact, so the vocal fold function is
intact. If there is a positive signal after stimulation of only the RLN and not the vagus nerve, it
means that there is usually a RLN paresis with a
lesion distally located to the stimulation site.
However, neuromonitoring detects only
neurogenic causes of RLN palsy and cannot
predict a palsy induced by postoperative hematoma or edema. Multicentric studies have
demonstrated lower rates of transient and permanent RLN palsy rates in comparison with
conventional RLN identification [15–17]. The
learning curve for an optimal use of this technique is estimated to 100 operations.
Minimally Invasive
Thyroidectomy
Endoscopic neck surgery was first described
for parathyroidectomy by Gagner in 1996
[18], and subsequently proposed for thyroid
surgery. Four techniques are currently performed: two complete endoscopic techniques
and two video-assisted techniques. These techniques are safe and reproducible but indicated
only in selected patients (see Table 12.1).
Intraoperative
Neuromonitoring
In the literature, it is well demonstrated that
identification of the RLN reduces the incidence
of nerve palsy [15–17]. The principle of neuromonitoring is based on instrumental testing of
the reflex arc between the RLN or the vagus
nerve and the vocalis muscle. The stimulating
electrode is inserted in the vocalis muscle
directly or placed at the surface of an endotracheal tube. To ensure the correct response, exact
placement of the tube is necessary and no repetitive administration of curare after the initial
Table 12.1. Relative indications of minimal invasive
thyroidectomy
Indications
Nodule <3cmof
diameter
Thyroid estimated
volume
<20 mL
Benign or low-
grade follicular
lesion
Low-risk papillary
carcinoma
Absolute
contraindications
Previous neck
surgery
Large goiter Hyperthyroidism
Locally advanced
cancer
Lymph node
metastases
Relative
contraindications
Previous neck
irradiation
Thyroiditis
169
TECHNIQUE OF THYROIDECTOMY
Complete Endoscopic Thyroidectomy
Gagner Technique
The patient under general endotracheal anesthesia is placed in the supine position with neck
hyperextension. A 5-mm horizontal incision is
performed above the sternal notch. The cervical
fascia is opened and the space below
the platysma is developed. A 5-mm trocar is
inserted into the subplatysmal space and secured
with a purse string suture. Pressure insufflation
is limited to 10 mm Hg. Initial dissection along
the anteromedial border of the ipsilateral sternocleidomastoid muscle (SCM) is performed by
advancing a 08 endoscope. Once an adequate
avascular space has been created, a 308 endoscope is used. Additional trocars are inserted
under direct vision: a 2- to 3-mm trocar at the
midline, a 2- to3-mm trocar at the midportion of
the ipsilateral SCM, and a 5- to 10-mm trocar
along the anterior border of the SCM. The sternohyoid and sternothyroid muscles are retracted
anteromedially after opening the linea alba with
the hook. The thyroid lobe is mobilized without
using cautery in the deeper tissue planes. The
middle thyroid vein is ligated using 5-mm clips
or the 5-mm harmonic scalpel. The RLN and the
parathyroid glands are identified and carefully
dissected from the thyroid gland. The inferior
thyroid artery is identified, ligated with 5-mm
clips as close as possible to the thyroid gland,
and divided with the RLN in full view. The superior pole vessels are isolated, clipped, and divided
when the superior laryngeal nerve has beenidentified. The inferior pole vessels are divided with
the harmonic scalpel. The Berry’s ligament is
divided with the harmonic scalpel after releasing
the anteromedial attachments of the RLN. The
specimen is then placed in a small bag (thumb
portion of a surgical glove) and extracted
through the superolateral trocar site. The skin is
closed with adhesive strips [19, 20].
Cougard Technique
This technique is a variant of Gagner technique
with central approach, which allows a bilateral
exploration of the neck with three trocars. The
patient is in the supine position with hyperextension of the neck. A 1.5-cm horizontal incision is made above the sternal notch. The
cervical fascia is opened and the linea alba is
divided. A space between superficial and deep
strap muscles is developed. A 5-mm trocar is
inserted into the subplatysmal space and
secured with a purse string suture. Pressure
insufflation is limited to 8 mm Hg. A 08 5-mm
endoscope isinserted.A working space is created
with the camera. One 3-mm trocar is inserted
under direct vision, to avoid anterior jugular
veins, on the left side and a 5-mm trocar on the
right side. The sternohyoid and sternothyroid
muscles are retracted anteromedially. After
mobilization of the thyroid lobe, the inferior
thyroid veins are first ligated by clips or 5-mm
harmonic scalpel and divided, followed by the
middle thyroid vein. The superior pole vessels
are isolated after identification of the superior
laryngeal nerve and ligated. The inferior thyroid
artery is isolated and ligated after identification
and preservation of the RLN and the parathyroid
glands. Isthmus is divided using harmonic scalpel and extracted by midline incision. The incisions are closed with surgical glue [21].
Video-Assisted Technique (MIVAT)
Lateral Approach: Henry Technique
The patient is in a supine position without
hyperextension of the neck to avoid traction of
the SCM and strap muscles. A 12- to 15-mm a
transverse neck incision is made just above the
isthmus. The anterior border of the SCM is
liberated from the cervical fascia and the thyroid lobe to the carotid sheath up to the prevertebral fascia. The superior limit of the dissection
is the omohyoid muscle. To enlarge the space of
dissection, a moist swab is stuffed upward and
downward. Two 2.5-mm ports are inserted on
the line of the anterior border of the SCM, 6 cm
above and 3–4 cm below the first skin incision.
These are inserted by passing a sharp trocar
under direct vision, (from in to out) via the
initial incision and then using this trocar as a
guide stick to insert the working ports (from out
to in). Then a 10-mm trocar is inserted through
the incision. Pressure insufflation is limited
to 8 mm Hg. All dissection is performed with
10-mm 08 endoscope and 2-mm graspers and
scissors. The dissection starts with the identification of anatomic structures, particularly the
RLN. The thyroid lobe is mobilized. Small vessels are cauterized. The branch of the inferior
thyroid artery is isolated but not ligated. The