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43 Craniofacial Resection
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459
43.12 Summary
Treatment of anterior skull base malignant neoplasms is complex and requires experienced multidisciplinary team involvement. There remains a need for craniofacial surgery, both with
open and endoscopic approaches, being performed in a safe
and effective manner. As cases are relatively infrequent on a
population basis, supraregional specialisation in surgical practice should be encouraged. Integrated approaches combining
surgical planning with adjuvant post- operative proton beam
therapy will allow more targeted treatment with the aim of
improving outcomes and reducing morbidity.
References
1. Mani N, Shah JP.Anterior skull base tumours: squamous cell carcinoma and its variants. Adv Otorhinolaryngol. 2020;84:124–36.
2. Lewis JS, Castro EB. Cancer of the nasal cavity and paranasal
sinuses. J Laryngol Otol. 1972;86(3):255–62.
3. Ketcham AS, Wilkins RH, Vanburen JM, Smith RR.A combined
intracranial facial approach to the paranasal sinuses. Am J Surg.
1963;106:698–703.
4. Shah JP, Kraus DH, Bilsky MH, Gutin PH, Harrison LH,
Strong EW. Craniofacial resection for malignant tumors involving the anterior skull base. Arch Otolaryngol Head Neck Surg.
1997;123(12):1312–7.
5. Raveh J, Laedrach K, Speiser M, Chen J, Vuillemin T, Seiler R,
Ebeling U, Leibinger K.The subcranial approach for fronto-orbital
and anteroposterior skull-base tumors. Arch Otolaryngol Head
Neck Surg. 1993;119(4):385–93.
6. Raveh J, Turk JB, Lädrach K, Seiler R, Godoy N, Chen J,
Paladino J, Virag M, Leibinger K. Extended anterior subcranial
approach for skull base tumors: long-term results. J Neurosurg.
1995;82(6):1002–10.
7. Hanna E, DeMonte F, Ibrahim S, Roberts D, Levine N, Kupferman
M. Endoscopic resection of sinonasal cancers with and without
craniotomy: oncologic results. Arch Otolaryngol Head Neck Surg.
2009;135(12):1219–24.
8. Wang EW, Gardner PA, Zanation AM. International consensus
statement on endoscopic skull-base surgery: executive summary.
Int Forum Allergy Rhinol. 2019;9(S3):S127–44.
9. Patel SG, Singh B, Polluri A, Bridger PG, Cantu G, Cheesman AD,
deSa GM, Donald P, Fliss D, Gullane P, Janecka I, Kamata SE,
Kowalski LP, Kraus DH, Levine PA, dos Santos LR, Pradhan S,
Schramm V, Snyderman C, Wei WI, Shah JP.Craniofacial surgery
for malignant skull base tumors: report of an international collaborative study. Cancer. 2003;98(6):1179–87.
10. Bentz BG, Bilsky MH, Shah JP, Kraus D. Anterior skull base surgery for malignant tumors: a multivariate analysis of 27 years of
experience. Head Neck. 2003;25:515–20.
11. Takes RP, Ferlito A, Silver CE, Rinaldo A, Medina JE, Robbins KT,
Rodrigo JP, Hamoir M, Suárez C, Zbären P, Mondin V, Shaha AR,
Mendenhall WM, Strojan P.The controversy in the management of
the N0 neck for squamous cell carcinoma of the maxillary sinus.
Eur Arch Otorhinolaryngol. 2014;271(5):899–904.
12. Sagheb K, Sagheb K, Taylor KJ, Al-Nawas B, Walter C.Cervical
metastases of squamous cell carcinoma of the maxilla: a retrospective study of 25 years. Clin Oral Investig. 2014;18(4):1221–7.
13. Homma A, Hayashi R, Matsuura K, Kato K, Kawabata K, Monden
N, Hasegawa Y, Onitsuka T, Fujimoto Y, Iwae S, Okami K,
Matsuzuka T, Yoshino K, Nibu K, Kato T, Nishino H, Asakage T,
Ota I, Kitamura M, Kubota A, Ueda T, Ikebuchi K, Watanabe A,
Fujii M. Lymph node metastasis in t4 maxillary sinus squamous
cell carcinoma: incidence and treatment outcome. Ann Surg Oncol.
2014;21(5):1706–10.
14. Dooley L, Shah JP. Management of the neck in maxillary
sinus carcinomas. Curr Opin Otolaryngol Head Neck Surg.
2015;23(2):107–11.
Part XVIII
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Thyroid Surgery
Total Unilateral Lobectomy
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andIsthmusectomy
PeterLoizou, BrianFish, andFaruqueRiat
44
Thyroid surgery is one of the most commonly performed surgical head and neck procedures. It is important to understand
the anatomy of the thyroid—and the pathology it can be
associated with—when considering the surgical removal of
part or all of the thyroid gland. In this chapter, we discuss the
use of intraoperative nerve monitoring of the recurrent laryngeal nerve (RLN) with a monitoring endotracheal tube with
electrodes at the level of the cords and the use of a nerve
stimulator probe. Positioning of the patient is also described
to optimise access and exposure during surgery. A step-bystep surgical approach is described, from making the incision, separating the strap muscles and dissecting the thyroid
gland, with the preservation of the parathyroid glands and
the RLN.Surgical technique and the use of energy instruments when dividing the vascular pedicles are also included.
Once the specimen is removed, haemostasis and wound closure are important nal steps for a successful outcome and
reducing post-operative complications. A brief description
on post-operative management and assessment concludes
this chapter.
44.1 Introduction
The thyroid gland is a buttery-shaped endocrine gland in
the anterior neck situated along the anterior surface of the
proximal trachea. This gland excretes the hormones thyrox-
P. Loizou (*)
Department of Otolaryngology, Head and Neck Surgery, Westmead
Hospital, Sydney, Australia
B. Fish
Department of Otolaryngology and Head and Neck Surgery,
Addenbrooke’s Hospital, Cambridge University Hospitals NHS
Trust, Cambridge, UK
e-mail: Brian.sh@addenbrookes.nhs.uk
F. Riffat
Westmead Private Hospital, University of Sydney,
Bella Vista, NSW, Australia
ine (T4) and triiodothyronine (T3), which are essential for
normal cell function and metabolism. These hormones are
important for regulating a number of physiological functions, and any disruption to their excretion can affect homeostatic control.
A number of different conditions can affect the thyroid
gland, including autoimmune conditions, infections, inammation, benign nodules and cancer. Some of these conditions are managed by surgical removal of all or part of the
thyroid gland, depending on the pathological state and diagnosis. Removal of all or part of the thyroid gland can affect
the release of thyroxine hormones, and if the adjacent parathyroid glands have been compromised, the effects on
excretion of parathyroid hormone affect calcium regulation.
Blood tests for serum calcium and parathyroid hormone are
only performed in the rst 24-h post-operative period after a
total or completion thyroidectomy, however. Thyroid function tests are generally done 4–6 weeks after a
hemi-thyroidectomy.
When considering surgery for thyroid pathology, it is
important to take into account the potential risks and the benets of having surgery. A unilateral thyroid lobectomy can be
satisfactory for management of a number of pathologies,
while normal thyroid function is maintained, and unnecessary risk to the contralateral side is prevented. This chapter
discusses unilateral thyroid lobectomy and isthmusectomy.
Surgical decision-making varies depending on diagnosis,
prognosis and patient factors and wishes. Surgeon factors
have also played a role in some instances, but they have now
been standardized in certain parts of the world through
adherence to guidelines and multidisciplinary team discussions. The diagnosis will be derived from a set of ‘gold standard’ investigations consisting of an ultrasonic scan (USS)
with or without ne needle aspiration cytology (FNAC), thyroid function tests (TFTs) and, in some instances, further
specic imaging and blood tests.
© Springer Nature Switzerland AG 2024
R. Simo et al. (eds.), Atlas of Head and Neck Surgery, Springer Surgery Atlas Series,
https://doi.org/10.1007/978-3-031-36593-5_44
463
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P. Loizou et al.
Table 44.1
Intra-operative complications:
• Bleeding
• Trauma to the nerves (RLN, SLN, sympathetic chain)
• Devascularisation/removal of parathyroid glands
• Thyroid storm
• Chyle leak
Post-operative complications:
• Immediate: Bleeding, haematoma, pain, hoarseness of voice,
• Early: Hypocalcaemia, wound infection, seroma
• Late: Hypothyroidism
RLN recurrent laryngeal nerve; SLN superior laryngeal nerve
Complications of thyroid surgery
stridor
The risks of thyroid surgery can be divided into intraoperative complications and immediate, early and late postoperative complications (Table44.1).
44.2 Preoperative Checklist,
Considerations andAnaesthesia
Prior to surgery, a patient should be fully informed about the
diagnosis and indication for surgery. The surgical risk and
benets should be explained in a comprehensive manner and
any questions answered. Information leaets are also helpful
in the preoperative and postoperative periods.
While booking the patient for surgery, the surgeon will
decide whether the patient is appropriate to be listed as a
day-case [1], although this practice is not endorsed by all
national thyroid surgery associations [2]. This decision
depends on factors that include patient co-morbidities,
American Society of Anesthesiologists (ASA) grading, the
potential need for a drain, recurrent laryngeal nerve (RLN)
paresis on the contralateral side, whether it is a completion
procedure, and patient social factors.
Each patient should have preoperative TFTs to conrm
that he or she is biochemically euthyroid. Vocal cord mobility also should be checked.
On the day of surgery, the preoperative checklist will
include identifying the patient by name, date of birth and
hospital identication number. It will also entail conrming
the patient’s consent and the side of the procedure, ensuring
that this correlates with the imaging and reports. The side
should then be marked with an arrow and ideally initials of
the marking team member. Some surgeons advocate antibiotic prophylaxis, but this remains controversial [3].
Increasingly, recurrent laryngeal nerve monitoring is
being used. If this is the case, the anaesthetist needs to be
aware that a monitoring endotracheal tube must be inserted,
with the electrodes being at the level of the cords
(Fig.44.1). If the view of the cords is not ideal when positioning the endotracheal tube, a C-MAC video laryngoscope can be used for conrmation. There are a number of
options for intraoperative monitoring and stimulation of
the RLN.It is important that the anaesthetist uses a shortacting paralytic agent (such as vecuronium, which has a
duration of 30–40min) so as to allow for use of the monitor and nerve stimulator when that part of the procedure is
reached.
The other variations in thyroid surgery, which are surgeondependent, are the technique adopted and the instruments
used, particularly for managing the vascular pedicles. The
advent of energy instruments including the Harmonic Scalpel
and LigaSure has enabled surgeons to manage the vascular
pedicles in a safe and efcient way by means of cautery and
simultaneous cutting. These can also aid in bloodless dissection of the gland and division of the isthmus and strap muscles, when necessary. In our practices, we use the Harmonic
Scalpel (Ethicon UK), as we feel it is not only safe but also
reduces operative time, as shown in a retrospective clinical
review by Foreman etal. [4].
In unilateral thyroid lobectomy, drains are not commonly
used, but this decision may change if the surgeon has a concern about increased bleeding risk or possible chyle leak. We
do not routinely insert drains in our patients who undergo a
unilateral thyroid lobectomy or isthmusectomy.
Another postoperative consideration is the need for adequate analgesia. This is not usually a painful procedure, but
the patient should be advised about a likely sore throat and
possible hoarseness. If the thyroid lobectomy is a completion
procedure, post-operative blood tests to assess levels of
serum calcium should be taken at 6 and 12h after surgery.
Some surgeons favour starting this patient subgroup on calcium supplements and thyroxine supplementation, but others
will not prescribe calcium supplements unless hypocalcaemia is reported or the patient is symptomatic. These steps are
not required for a standard unilateral thyroid lobectomy or
isthmusectomy.
44 Total Unilateral Lobectomy andIsthmusectomy
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Fig. 44.1 Electromyogram
endotracheal tube
44.3 Indications
Broadly speaking, the indications for a unilateral thyroid
lobectomy or isthmusectomy are to remove the part of the
thyroid gland containing a lesion [5, 6]:
• Single large nodule, for diagnostic or therapeutic reasons
• Recurrent thyroid cyst
• Toxic nodule
• Large multinodular lobe leading to compressive symptoms of the aerodigestive tract
• Large single nodule or multinodular lobe leading to
unsightly appearance of the neck
465
Other indications whereby a lobectomy is recommended
include features on USS that may be suspicious for a thyroid
malignancy and for patients in a high-risk category or
hereditary subgroup. A common indication for a thyroid
lobectomy is when FNAC comes back as a Thy3, consistent
with follicular cytology giving rise to a diagnostic dilemma
as to whether the lesion is an adenoma or carcinoma. A diagnostic lobectomy allows for histological assessment in the
pathology lab and can be sent in formalin unless there is the
uncommon concern of lymphoma, whereby tissue should be
sent off as a fresh specimen. All malignant lesions conrmed
on histology should then be discussed at a thyroid multidisciplinary meeting (MDM) for decisions on staging, prognosis, and further management and treatment planning. Thyroid
lobectomy may be the only treatment required for small,
well-differentiated thyroid carcinomas.
44.4 Surgical Technique
Just before the commencement of surgery, it is important to
position the patient on the operating table after the anaesthetist has secured the endotracheal tube, being careful not to
move the tube, especially if it is a correctly positioned monitoring tube. We tend to favour using a shoulder bolster
formed of 1L bag of saline wrapped in a disposable pad. The
head is gently laid on a soft head ring, and the patient is posi-
Fig. 44.2 Marking of transverse neck crease and topographical
landmarks
tioned with the neck hyperextended, making sure not to have
the head in suspension or unsupported. The limit of hyperextension varies with each patient owing to anatomy, body
habitus and cervical spine condition and stiffness. The head
of the bed is raised 15–30°, to reduce venous pressure and
hence intraoperative bleeding. If a monitored tube is being
used, the electrode can be placed on the patient’s upper sternal area or shoulder, and the monitoring equipment is
checked before prepping and draping of the patient.
Once in a satisfactory position, the patient’s neck can be
marked with a surgical pen (Fig.44.2), although some surgeons advocate marking the patient whilst they are awake.
We tend to mark topographical landmarks, which are obvious in some patients but need to be carefully palpated in others. These include the thyroid notch, the cricoid and the
sternal notch, with a dotted line running along the medial
borders of the sternocleidomastoid (SCM) muscles. This
marking helps in visualizing the potential surgical eld once
exposed and also makes it possible to choose an optimally
positioned natural skin crease for the transverse cervical
incision, the length of which will depend on the patient:
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P. Loizou et al.
long, slender neck versus short, fat neck; the size of the lobe
(large, multinodular, or with retrosternal extension); and in
some instances, the presence of a previous transverse scar.
The recognition of anatomical and pathological abnormalities allows for the consideration of alternative or adjusted
operative strategies and the adequate preparation to deal with
them.
At this point, some surgeons inltrate the skin and subcutaneous tissue with a local anaesthetic with or without adrenaline. While allowing for the vasoconstrictive effects of the
adrenaline, the surgical team can get scrubbed and gowned
while the scrub nurse prepares the skin with betadine and
drapes the patient.
Once the patient is draped and the energy sources and
instruments are checked, the skin incision can be made.
Ideally, a 10- or 15-blade scalpel can be used for this initial
step, making sure the belly of the blade runs along the skin in
a perpendicular fashion to avoid bevelling of the skin and
maintain the cleanest cut for optimal primary closure at the
end of the procedure. Some surgeons favour using the Bovie
knife or Colorado needle for the incision, on the pure cut setting of 25–30. (If using monopolar electrical instruments, a
return grounding pad must be carefully placed on the
patient’s skin.) We prefer using a ten blade for our skin
incision.
Once through the skin, the monopolar spatula is used to
carefully cut through the platysma muscle bres in the same
transverse direction up to the limits of the skin incision, to
allow for maximal exposure. Subplatysmal aps can then be
raised. To achieve this, adequate retraction with cats’ paws in
an upward vertical direction by a surgical assistant at the
head of the table allows the upper ap to be raised to the level
of the thyroid notch. The assistant can then move to the side
of the patient opposite the primary surgeon, to allow for the
lower subplatysmal ap to be elevated down to the level of
the sternal notch. The surgeon can simultaneously retract the
underlying strap muscles and fascia in a downward direction
to maintain tension in the fascia, proceeding with purposeful
dissection above the anterior jugular veins but below the platysma. If the anterior jugular veins are encountered medially,
they can be ligated and divided with Vicryl ties or using the
Harmonic Scalpel. Careful and purposeful dissection in the
correct tissue planes maintains a bloodless surgical eld,
which is of paramount importance during thyroid surgery so
as to avoid soiling of the surgical bed and reduce the chances
of inadvertent trauma to the RLN.Once these aps are elevated, a Jolls retractor has historically been used, but now
disposable Lone Star elastic stays or 2/0 silk sutures can be
attached to the drapes with artery clips or mosquito forceps,
pulling the adequately raised aps in a four-direction
exposure.
The midline is then identied in order to separate the strap
muscles along their raphe at the linea alba up to the thyroid
notch and then down to the sternal notch. The skin is at its
thinnest over the thyroid notch, so care must be taken not to
buttonhole it there. This step can be facilitated with a
medium-sized Langenbeck retractor held by the assistant at
the upper and lower ends of the midline. The primary surgeon can pick up the overlying fascia and the medial borders
of the strap muscle to allow for easier dissection of the raphe.
The side to be operated on is again conrmed, and if it is
the surgeon’s preference to divide the isthmus at this stage,
then the upper and lower edges of the isthmus are identied.
The trachea is identied at the top and the lower end of the
isthmus, and large artery forceps can be used to nd the
plane between the undersurface of the gland and the trachea
before the isthmus is divided, taking great care not to damage the tracheal rings or cricothyroid membrane (Fig.44.3).
Great care should be taken at the lower end, as high rising
major vessels may be encountered at the thoracic inlet. The
isthmus can be clamped on either side of the midline with
large artery clips and then cut with a scissors. A hemitransxion 2/0 Vicryl suture can be used to tie off each end, but
this can also be achieved safely and effectively with a harmonic scalpel. Any bleeding during this step can also be
managed with careful bipolar haemostasis. If the nodule or
lesion is within the thyroid isthmus, then it can be divided
along the lateral aspect of the lesion to complete the isthmusectomy. Alternatively, the isthmus can be divided once the
thyroid lobe has been dissected.
Unless the lobe to be removed is large, the strap muscles
do not necessarily need to be divided as long as there is satisfactory exposure. If they need to be divided, then an
accepted technique is the partial cutting of the sternothyroid
muscle at the superior half to expose the superior pedicle [7].
This can be performed using the harmonic scalpel. Further
careful dissection of the fascial planes under the strap and
overlying the now-exposed thyroid gland can be achieved
with a dry or an adrenaline-soaked 1:10,000 pledget, sweeping in a direction upwards and away from the gland, moving
laterally until the carotid sheath can be identied. At this
point, the middle thyroid vein may be encountered; it can be
ligated with a tie, an energy instrument or a Ligaclip®
(Ethicon).
The assistant can then use two small Langenbeck retractors to expose the superior pole. Using ne-tipped mosquito
forceps or a vasectomy forceps, the fascial pocket between
the medial aspect of the superior pole and the inferior constrictor muscles is carefully dissected, to avoid shearing of
any small vessels or damage to the external branch of the
superior laryngeal nerve (EBSLN). Once the superior pedicle is identied (taking care not to damage the SLN or the
superior parathyroid gland), the pedicle can be ligated close
to the gland (Fig.44.4). This ligation can be achieved more
effectively by retracting the superior pole of the thyroid
downwards with an Allis forceps or Babcock, with the assistant retracting in an oblique direction with the Langenbeck
retractors positioned at the cephalad and vertical vectors. We
44 Total Unilateral Lobectomy andIsthmusectomy
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Fig. 44.3 Division of the isthmus
467
Fig. 44.4 Identication and ligation of the superior pedicle of the left thyroid lobe
use a Harmonic Scalpel for this step, always having the tips
of these energy instruments in full view. A traditional method
of using 2/0 Vicryl ties can also be used, or even manual
titanium Ligaclip® applicators, depending on the diameter of
the vessels of the vascular pedicle.
Now that the superior pole is mobilised, careful intracapsular dissection is performed close to the thyroid gland with
a ne-tipped dissector, avoiding going into the tracheoesophageal groove until the thyroid lobe is delivered outwards and
medially. The inferior parathyroid gland is often closely
adherent to the lower part of the thyroid gland; it should be
carefully dissected off, preserving its blood supply from the
inferior thyroid artery (ITA). Moving inferiorly towards the
inferior pole of the thyroid, careful dissection is important,
as the RLN can pass anterior or posterior to the ITA, or even
between its branches as it approaches the thyroid gland [8].
Identication of the nerve is advocated by most surgeons;
important landmarks used to do this safely include its relation to the ITA, the tracheoesophageal groove, Berry’s ligament and the tubercle of Zuckerkandl [6]. It must also be
remembered that it is not uncommon for the nerve to divide
in the neck prior to entering the larynx.
Once the nerve and the parathyroid glands have been
safely identied and preserved, then the lobe can be removed
at Berry’s ligament with the RLN entering the cricothyroid
joint in full view. If the left lobe is being removed, then the
pyramidal lobe should also be identied and removed with
the specimen. If a parathyroid gland is inadvertently removed
with the specimen or is obviously devascularised, it can be
carefully dissected off, morselised and re-implanted in a
small muscular pocket created in the SCM, which can be
marked with a nylon suture or a Ligaclip®.
At this point, if the nerve monitor is being used, the RLN
can be stimulated with a nerve stimulating probe to assess
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Fig. 44.5 Identication and stimulation of the recurrent laryngeal nerve
P. Loizou et al.
and conrm its integrity (Fig.44.5). The surgeon should then
ask for the head of the bed to be lowered and ask the anaesthetist to induce a Valsalva to increase the blood pressure and
look for any bleeding points in the surgical eld. Bipolar
haemostasis can be used for this, taking care with any bleeding points close to the RLN.If there is minimal oozing on or
very close to the nerve, a haemostatic agent such as Surgicel®
(Ethicon), a cellulose polymer, can be placed gently over the
RLN along the tracheoesophageal groove.
The surgery is now almost complete, with closure being the
nal step. This is still an important part of the surgery, as close
approximation of the strap muscles avoids any adherence of
the trachea to the subcutaneous layer, which can lead to
unsightly tethering. The straps can be brought together at the
midline with interrupted 3/0 Vicryl sutures, leaving a small
opening inferiorly in case any haematoma accumulates and
requires urgent evacuation post-operatively. The platysmal
layer is also closed using 3/0 Vicryl interrupted sutures. For
skin, the primary wound closure method of choice varies from
a 4/0 Monocryl subcuticular suture to skin glue; staples are
now used less commonly. A sound wound repair is relatively
important to the patient, as it will optimise the cosmetic outcome. If the skin has been closed via the subcuticular method,
then the wound can also be dressed with Steri-Strips.
44.5 Post-operative Care
Once the patient has been extubated and transferred to the
recovery area, close post-operative observations can highlight any concerns to the surgical or anaesthetic team.
It is important for the surgical team to assess the wound
and the patient’s airway before the patient can be considered
safe for discharge. The wound should be kept dry for the rst
week if sutures or clips have been used for skin closure, and
any sutures should be removed by day 7. Before discharge,
scar care advice is provided to the patient, and information
about possible postoperative complications should be
highlighted.
The movement of the vocal cords should be assessed
post-operatively with some surgeons doing this prior to discharge and others waiting until the rst post-operative clinic
visit. Thyroid function testing should not be performed until
4–6weeks post-operatively.
References
1. de Boisanger L, Blackwell N, Magos T, Adamson R, Hilmi O.Day
case hemithyroidectomy is safe and feasible: experience in Scotland.
Scott Med J. 2015;60:239–43.
2. Doran HE, England J, Palazzo F, British Association of Endocrine
and Thyroid Surgeons. Questionable safety of thyroid surgery with
same day discharge. Ann R Coll Surg Engl. 2012;94:543–7.
3. Fachinetti A, Chiappa C, Arlant V, Kim HY, Liu X, Sun H, et al.
Antibiotic prophylaxis in thyroid surgery. Gland Surg. 2017;6:525–9.
4. Foreman E, Aspinall S, Bliss RD, Lennard TW.The use of the har-
monic scalpel in thyroidectomy: ‘beyond the learning curve’. Ann
R Coll Surg Engl. 2009;91:214–6.
5. Lansford CD, Teknos TN.Evaluation of thyroid nodule. Cancer
Control. 2006;13:89–98.
6. Dhir M, McCoy KL, Ohori NP, Adkisson CD, LeBeau SO, Carty SE,
Yip L.Correct extent of thyroidectomy is poorly predicted preop-
eratively by the guidelines of the American Thyroid Association for
low and intermediate risk thyroid cancers. Surgery. 2018;163:81–7.
7. Tinckler LF.Strap muscles in thyroid surgery: to cut or not to cut?
Ann R Coll Surg Engl. 1993;75:378–9.
8. Shindo ML, Wu JC, Park EE. Surgical anatomy of the recur-
rent laryngeal nerve revisited. Otolaryngol Head Neck Surg.
2005;133:514–9.
Isthmusectomy andSubtotal
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Thyroidectomy
KatherineBlack andJohnathanHubbard
45
45.1 Introduction
The standard approach to most thyroid surgery involves
complete resection of one or both lobes, along with the
isthmus. This requires exposure of the tracheo-oesophageal
groove, which poses a risk to the recurrent laryngeal nerve
and the parathyroid glands, leading to potential postoperative complications of hoarseness and hypocalcaemia.
A more limited resection, such as isthmusectomy or subtotal thyroidectomy, may decrease the risk of such
complications.
The isthmus is the central part of the thyroid gland that
connects the right and left lobes and lies directly anterior to
the trachea. An isthmusectomy involves resection of this
central section and may be suitable for thyroid nodules localised to this area. By avoiding further dissection, this approach
minimises the risk of damage to the recurrent laryngeal
nerves and parathyroid glands. It also limits the amount of
thyroid parenchyma excised, so the requirement for thyroxine supplementation post-operatively should be low.
Subtotal thyroidectomy involves removing the majority
of the thyroid gland but leaving a remnant of thyroid tissue in
situ posteriorly. It may be considered an option for benign
multinodular goitres and Graves’ disease [1–3]. The arguable benet again being that it may reduce the risk of recurrent laryngeal nerve injury and post-operative
hypoparathyroidism and potentially reduce the need for thyroxine replacement. However, there is no consensus on the
amount of thyroid tissue left behind, so the term subtotal thyroidectomy is imprecise and should be avoided [2, 4, 5]. It
risks persistent/recurrent hyperthyroidism or goitre recurrence, without guaranteeing preservation of thyroid function
as it is difcult to quantify the adequate volume of thyroid
remnants. Furthermore, total thyroidectomy is considered a
K. Black (*) · J. Hubbard
Department of General Surgery, Guy’s and St Thomas’ NHS
Foundation Trust, London, UK
e-mail: k.black@uq.edu.au; johnathan.hubbard@gstt.nhs.uk
safe procedure with minimal morbidity when performed by
an experienced surgeon, and studies show that there is no
difference in rates of complications between the two methods [1, 6]. Total thyroidectomy has a lower recurrence rate
than subtotal thyroidectomy and avoids any need for reoperative surgery, which may in turn have higher complications [1–3, 6]. As such, subtotal thyroidectomy is not
performed as often as it had been previously and is not performed by the authors.
45.2 Preoperative Checklist,
Considerations andAnaesthesia
Before surgery, the patient should always be informed about
the indication for surgery, the potential risks and benets and
alternative options.
The procedure is performed under a general anaesthetic.
The patient is positioned on the operating table with the neck
extended using a shoulder roll and head supported with head
ring, being careful to avoid overextending or head hanging.
The patient arms are tucked in by their side. The bed is positioned so that there is elevation of the head to help in decreasing venous congestion. The bed can also be turned around
away from the anaesthetist to allow more room for surgeon
and assistants. After appropriate antiseptic preparation has
been applied, then the surgical eld is draped allowing exposure from the chin to below the sternal notch and laterally
beyond the sternocleoidomastoid muscles (Fig.45.1). Local
anaesthetic with adrenaline is inltrated into the subcutaneous tissue along the line of the incision at the beginning of
the procedures to help reduce bleeding and to avoid local
anaesthetic topically on the laryngeal nerves at the end of
procedure, which may cause a transient vocal cord
paralysis.
© Springer Nature Switzerland AG 2024
R. Simo et al. (eds.), Atlas of Head and Neck Surgery, Springer Surgery Atlas Series,
https://doi.org/10.1007/978-3-031-36593-5_45
469
470
https://t.me/med1917
Fig. 45.1 The surgical eld is draped allowing exposure from the chin to below the sternal notch, and skin crease incision is marked
K. Black and J. Hubbard
45.3 Indications
The indication for isthmusectomy would be for a solitary
thyroid nodule localised to the isthmus. A benign thyroid
nodule, being excised for symptomatic reasons, for example,
would be the ideal indication for this approach [7–9]. In
cases of indeterminate nodules, isthmusectomy with excision of the lesion with a small margin of normal tissue may
be an appropriate diagnostic procedure, but the patient
should be warned of the potential recommendation for further surgery depending on the nal histology.
Performing isthmusectomy for biopsy-proven malignant
nodules conned to the isthmus is more controversial.
Lesions of the isthmus occur in less than 10% of patients
with thyroid cancer, and there are limited studies investigating the outcomes of this approach. A few studies support the
use of isthmusectomy for small, well-differentiated thyroid
cancers with no extrathyroidal extension or other risk factors
[10–12]. These are low risk cancers, which will not require
post-operative radioactive iodine and have excellent longterm survival rates. Other studies suggest that papillary thyroid cancers located in the isthmus were more likely to be
associated with multifocal disease, lymph node involvement
and capsule invasion, proposing isthmusectomy would be
inadequate [9, 13–17]. Current guidelines do not specically
describe management of thyroid cancers isolated to the isthmus [5, 18]. But as more conservative management of thyroid cancers is being favoured, this may become a more
common technique.
Subtotal thyroidectomy should only be considered for
benign conditions, such as Grave’s disease or symptomatic
goitre. However, as discussed earlier, these conditions would
now be more commonly treated with a total thyroidectomy
[19]. Subtotal thyroidectomy is not an appropriate option for
malignant nodules.
45.4 Surgical Technique withTips
45.4.1 Incision andAccess
The initial incision and access for an isthmusectomy and
subtotal thyroidectomy are the same as for most standard
thyroid surgery. A Kocher’s incision is performed transversally along the lines of the skin, approximately two ngerbreadths above the sternal notch, for a length that may vary
depending on the size of the thyroid or nodule for excision.
The incision is continued through the subcutaneous tissue
and platysma muscle.
Subplatysmal aps are created upward to the level of the
thyroid cartilage and downward to sternal border, avoiding
damage to the anterior jugular veins. The strap muscles are
separated in the midline until thyroid isthmus is reached, and
this dissection is extended from the level of the thyroid cartilage to the suprasternal notch. The author doesn’t use a selfretaining retractor but rather uses small handheld
(Langenbeck) retractors, which allow the ability to adjust
retraction depending on the focus area at the time, therefore
allowing a smaller incision.
45.4.2 Isthmusectomy
The isthmus is exposed further by elevating the strap muscles away from the thyroid capsule and continued laterally
until the boundaries of the lesion are visible, with an adequate margin of normal thyroid parenchyma (Fig.45.2). The
inferior border of the isthmus is dened, and any inferior
thyroid veins present are divided, thereby exposing the anterior surface of the trachea (Figs.45.3 and 45.4).
The lateral boundary of excision is dened, ensuring adequate margin around the lesion, and the thyroid is divided
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