Download Management of Invasive Thyroid Carcinoma

Head & Neck Surgery Course
Surgical anatomy of thyroid
and parathyroid glands
Dr Pierfrancesco PELLICCIA
Pr Benjamin LALLEMANT
Service ORL et CMF
CHU de Nîmes
CH de Arles
Thyroid glands
Dr Pierfrancesco PELLICCIA
Pr Benjamin LALLEMANT
Service ORL et CMF
CHU de Nîmes
CH de Arles
Introduction
• Thyroid gland includes 2
lobes and isthmus
• Endocrine gland
– T3, T4, CT
Thyroid region
• Boundaries
–
–
–
–
–
Superior: hyoid
Lateral: carotid sheath
Inferior: manubrium
Anterior: strap muscles and their fascia
Posterior : prevertebral fascia
Infrahyoid muscles
5
Middle layer of deep cervical fascia
Thyroid region: anterior view
Thyroid region: anterolateral view
Thyroid region: right lateral view
Thyroid region: left lateral view
Arterial supply
• Sup. & inf. thyroid arteries
• Superior and posterior
anastomotic arch
• Anatomy variant: thyroid
ima artery, in 1.5% to 12%,
in front of the trachea.
Arterial supply
Venous supply
– Superior and middle
thyroid v. drain into the
internal jugular
– Inferior thyroid v. drains
into the brachiocephalic
trunk
Nodular goiter and superior mediastinum
• Prevascular
• Retrovascular
Lymph vessels
• 1st echelon nodes:
prelaryngeal,
pretracheal and
paratracheal nodes
(level VI)
• 2nd echelon nodes:
– Level VII
– Level IIa-III-IV-Vb
Lymph vessels
Recurrent Laryngeal Nerve (RLN)
• Sim’s triangle
– Carotid artery
– Trachea
– Inferior pole of thyroid
• Left RLN runs parallel with
the tracheoesophagel
groove
• Right RLN runs diagonal
with the TEG
RLN
RLN is seen, in order of decreasing frequency:
- As a single nerve
- bifurcated (posterior branch=anastomotic
branch with the sympathetic or branch to
esophagus)
- Trifurcated
- Plexiform.
RLN
RLN
RLN and inferior thyroid artery
• RLN crosses branches of the artery in 75% of
cases, the trunk in 14%
and division in 11%.
• RLN is posterior to the artery in 47% of cases,
anterior in 28% of cases, between the
branches in 25%.
• So, 75% of RLN crosses the branches of artery,
but is between them just in 25% of cases.
RLN and inferior thyroid artery
• RLN crosses the trunk of the artery the most
often on the right side, the branches or
division the most often on the left side.
• RLN is found anteriorly the artery the most
often on the right side, and posteriorly on the
left side.
RLN and inferior thyroid artery
RLN and inferior thyroid artery
Non recurrent
inferior
laryngeal nerve
• Right side (<<1%)
• Aberrant right subclavian
artery
• Dysphagia lusoria
• Situs inversus
Non recurrent inferior laryngeal nerve
Berry ligament
Berry ligament
Posterior thyroid tubercle of
Zuckerkandl
Posterior thyroid tubercle of
Zuckerkandl
Superior Laryngeal Nerve
Parathyroid glands
Parathyroid glands
Dr Pierfrancesco PELLICCIA
Pr Benjamin LALLEMANT
Service ORL et CMF
CHU de Nîmes
CH de Arles
Introduction
• 4 endocrine glands (PTH)
• Autopsy studies suggest that four parathyroid
glands are virtually always present.
• Supernumerary glands can be identified in up
to 15% of patients, most often in association
with the thymus.
Embriology of parathyroids
•The superior parathyroid gland (P4)
arises from the fourth pharyngeal pouch
in conjunction with the lateral thyroid
• the inferior gland (P3) arises from the
third pouch along with the thymus.
•The derivatives of each pouch then
migrate together.
P4 and P3 are supposed to migrate down the neck to
end up next to and around the thyroid gland
Embriology of parathyroids
•P4 usually remains in close
association with the upper pole of the
thyroid
•It may occasionally be loosely
attached by a long vascular pedicle,
migrating caudad along the esophagus
into the posterior mediastinum
•Occasionally, a gland may be totally
embedded in the thyroid parenchyma.
Embriology of parathyroids
•P3 descends with the thymus, but this
migration is extremely variable.
•Regardless of their location, they
usually adhere to the thymus or are
within the thyrothymic ligament.
•Inferior glands can be found anywhere
from the pharynx to the mediastinum.
Blood supply of parathyroids
• Branches of the inferior thyroid artery
• Great variation exists, supply by the superior thyroid arteries, the thyroid ima artery,
the laryngeal arteries, tracheal arteries or oesophageal arteries has been
documented.
• The glands drain into the plexus of veins on the anterior surface (front) of the
thyroid comprising the superior, middle and inferior thyroid veins.
Blood supply of parathyroids
Parathyroid glands:
intraoperative view
Ectopic parathyroid glands
• If the gland does not migrate down
it will be found high in the neck
under the jaw (sestamibi scans!)
• If the parathyroid gland migrates
too far, it will end up in the chest
(about 15 times more common
than parathyroid glands that don’t
migrate far enough and end up
high in the neck)
Inferior Parathyroid Locations
Superior Parathyroid Locations
Where to look for parathyroid glands ?
• 1) 80 % of glands
• 2) 98 %
Where to look for parathyroid glands ?
• Look on the posterolateral
aspect of thyroid first (1)
• Then look on the
posteromedial aspect of
thyroid, around RLN (2)
• Then look in the
thyrothymic ligament and
around the thymus (3)
Where to look for P3 ?
• A. Usual location = 80 % of P3
• B. Usual location + most often encountered ectopic locations = 98 %
of P3
• C. Same as B + less often encountered ectopic locations = 100 % of P3
Where to
look for P4 ?
• D. Usual locations.
• E. Usual + ectopic locations
Distribution of 220 parathyroid
specimens of patients who
underwent reoperative neck
surgery because of persistent
hyperparathyroidism
136 parathyroid glands (61.8%)
located in their normal anatomical
positions
84 ectopic parathyroid glands
(38.2%)
Sites of ectopic location of 104 parathyroid glands found
at reoperation for primary hyperparathyroidism
(From Wang C-A. A clinical and pathological study of 112 cases. Ann Surg 1977;186:140-145.)