1. THYROIDECTOMY

2. HISTORY
● Term 'thyroid' was coined by Thomas Warton in
17th century
● Emil Theoder Kocher is considered as the
Father of Modern Thyroid surgery
● First thyroidectomy is considered to be done
more than 1000 years ago by Abu-al-Qasim
● The earliest account of thyroidectomy was
probably given by Roger Frugardi, 1170

3. EMBRYOLOGY
● Thyroid gland develops from the median anlage
and two lateral anlagen
● Median anlage starts as a thickening of
endodermal epithelium in foregut between 1st
and 2nd branchial arches at base of tongue
cells proliferate – thyroid bud and then a
diverticulum – expands and migrates to lie in
anterior to trachea (4-7 wks of gestation)
● The track usually disappears by birth

4. ● Two lateral anlagen (ultimobranchial bodies)
develop from caudal aspect of 4th pharyngeal
pouch
fuse with median anlage as thyroid gland
descends in the neck
● Median anlage follicular cells
● Lateral anlagen parafollicular cells

6. ANATOMY – Thyroid gland

7. ● Thyroid gland is composed of follicles which are
secreting functional units of the gland, together
with a rich vascular, lymphatic and neural
network
● The gland comprises of two lobes connected by
isthmus, lying in midline on trachea at level of
2nd-3rd tracheal ring
● Gland is invested in a fascial capsule –
'Surgical capsule' derived from the pretracheal
fascia of deep cervical fascia. It is thin and
closely related to external surface of gland

8. ● Capsule is deficient in posterior aspect of
isthmus and most of posteromedial surface of
lobe where gland lies in close relation to
trachea
● Along upper part of posterior border of thyroid
lobe and adjacent posteromedial surface fascia
is thick and firmly attached to trachea –
'Ligament of Berry'
● It binds gland firmly to trachea and must be freed
while releasing a lobe surgically
● RLN lies behind ligament of Berry just before it
disappears in larynx behind cricothyroid joint

9. ● Posteriorly capsule extends to blend with
prevertebral fascia
● Laterally with carotid sheath
● Superiorly envelopes upper lobe of gland and
extends upwards around superior pedicle
● Along upper border of isthmus fascia attaches
to outer surface of trachea and cricoid
● Inferiorly fascia passes into mediastinum
anterior to trachea and contains inferior thyroid
veins

10. ● Each lobe of the gland resides in a bed
between trachea and larynx medially & carotid
sheath and SCM laterally.
● Strap muscles lie anterior to the thyroid lobes
● Parathyroids and RLN are associated with
posterior surface of each lobe
● Superior pole lies posterior to sternothyroid
muscle and lateral to inferior constrictor &
posterior thyroid lamina
● Inferior pole may extend to level of 6th tracheal
ring

11. ● About 40% may have a 'pyramidal lobe' arising
from either lobe or isthmus and extends
superiorly. It represents remnants of embryonic
thyroglossal duct and lie on surface of thyroid
cartilage
● Tubercle of Zukerkandl – 75%
● Pyramidal enlargment of lateral edge of thyroid lobe
formed from fusion of median and lateral anlages
● Closely related to RLN, inferior thyroid A, ligament
of Berry and superior parathyroid gland

12. Arterial supply

13. ● Superior thyroid artery
● First branch of external carotid artery
● Course along inferior constrictor muscle and enters
upper pole of thyroid, and divides into superior and
inferior branches
● Superior branch runs along medial surface of upper
pole and along upper border of isthmus to anastose
with its fellow on opposite side
● Inferior branch descends along posterior border of
thyroid to anastomose with upper branch of inferior
thyroid artery
● Superior thyroid A lies posterolateral to external
branch of SLN

14. ● Inferior thyroid artery
● Arises from thyrocervical trunk
● Lies deep to common carotid artery and as it nears
gland divides into upper and lower branches
● Upper branch anastomoses with inferior branch of
superior thyroid artery
● Lower branch runs downwards towards inferior pole
of thyroid

15. ● Inferior thyroid artery provides an important
surgical landmark for RLN – In almost 70% of
patients inferior thyroid artery lies anterior to the
RLN.
● Thyroidea ima artery is occasionaly present –
arising from aortic arch / carotid artery

16. VENOUS DRAINAGE
● Superior thyroid vein accompanies the superior
thyroid artery and joins IJV
● Middle thyroid vein originate from anterolaterla
surface of gland and pass laterlally to join IJV
● Division of this vein permits adequate rotatiom of
thyroid lobe to identify RLN and parathyroid glands
● Inferior thyroid vein comes from inferior boeder
of gland and drain mainly to left brachiocephalic
vein, but also into IJV

17. NERVES
● Thyroid gland is innervated by symphatetic
fibres from middle cervical ganglia, fibres pass
into gland along with principal arteries to the
gland
● Recurrent laryngeal nerve
● Provides motor supply to larynx and some sensory
fibres to upper trachea and subglottis
● Right RLN arise from vagus (CN X) at base of neck,
loops around subclavian artery and ascends behind
right lobe of thyroid. It enters larynx behind
cricothyroid muscle between arch of cricoid
cartilage and inferior cornua of thyroid cartilage

18. ● Left RLN arise from left vagus at level of arch of
aorta, loops posteriorly around it and ascends in
tracheo-oesophageal groove, posterior to left lobe
of thyroid and enters larynx.
● Left RLN is in close relationship with inferior thyroid
artery (70%)
● Non RLN – may occur rarely seen on right side

19. ● External laryngeal nerve
● Subdivision of SLN
● SLN arises beneath nodose gangion of upper
vagus and descends medial to carotid sheath,
dividing into external and internal branches about
2cm above superior pole of thyroid
● Internal branch travels medially and enters posterior
thyrohyoid membrane supplying sensation to
supraglottis
● External branch extends medially along inferior
constrictor muscle to enter cricothyroid muscle

20. LYMPHATICS
● Lymphatic drainage of thyroid gland has been
proposed by Taylor. His studies shows clinically
relevant lymphatic spread in thyroid malignancy
● Central compartment of neck -
– Tracheal LN
– Chain of LN which lie in tracheo-oesophageal groove
– One or more LN lying above isthmus – 'delphian nodes'
● B/L central LN dissection (level 6 dissection)
– Clears all LN from carotid artery to other and down into
superior mediastinum

21. ● Lateral compartment of neck
● A constant group of LN lies along IJV on each side
(level 2,3,4). LN in supraclavicular fossa or more
laterally level 5 LN may also be involved in thyroid
malignancy
● Thoracic duct on left side of neck arches up out
of mediastinum and passes forwards and
laterally to drain into left subclavian vein / IJV
● Lateral LN dissection –
● removal of level 2, 3, 4 and 5 LN. Vagus N,
symphatheticc ganglia, phrenic N, brachial plexus
and spinal accessory N are preserved

22. PARATHYROID GLANDS
● They are small semilunar shaped, ochra
coloured glands,situated in a pad of fat
generally outside surgical capsule secreting
PTH, which controls serum Ca metabolism
● Gland are usually 4 in numbers, two on each
side, occasionally 3-6.
● Superior parathyroid glands -
● Develops from 4th pharyngeal pouch and descend
only slightly during devvelopment and their position
remains constant in adult life

23. ● Generally found at level of pharyngo-oesophageal
junction behind and seperate from posterior border
of thyroid gland
● Supplied by branch from upper division of inferior
thyroid artery
● Inferior parathyroid glands
● Arise from 3rd pharyngeal pouch along with thymus
● Descend along with thymus and have a wide range
of distribution in adults
● Usually located short distance from lower pole of
thyroid
● Supplied by inferior terminal branch of inferior
thyroid artery

25. Thyroidectomy
● INDICATIONS
● As therapy for patients with thyrotoxicosis
● To treat benign and malignant thyroid tumours
● To alleviate pressure symptoms (respiratory
distress, dysphagia) with benign/ malignant process
● Cosmetic purpose
● To establish a definitive diasgnosis of a mass within
thyroid gland, especialy when cytological analysis is
either non diagnostic or indeterminate

26. TYPES
● Thyroid lobectomy / Hemithyroidectomy
● Subtotal thyroidectomy
● Near total thyroidectomy
● Total thyroidectomy
● Completion thyroidectomy

27. PRE OPERATIVE EVALUATION
● Ultrasonography
● Fine needle aspiration cytology – FNAC
● Thyroid function tests – TFT
● CT scan
● Thyroid uptake scan
● Laryngoscopy
● Serum Calcium, Parathormone (PTH)

28. PRE OPERATIVE PREPARATION
● Hypothyroidism
● Hyperthyroidism

29. PRE OPERATIVE CONSENT
● Scar
● Airway obstruction
● Voice changes
● Hypoparathyroidism
● Hypothyroidism

30. OPERATIVE STEPS
● Anaesthesia, Positioning & Draping

31. ● Skin incision and creation of flaps

33. Exposure of thyroid gland

34. Mobilization and dissection of upper
pole

35. Identification of RLN

37. Identification of parathyroid glands

38. Dissection of ITA and removal of
gland

40. Closure

41. POST OPERATIVE CARE
● Look for signs of bleeding, respiratory distress
● Serum Calcium
● Removal of drain
● Reassessment of vocal cord mobility and
thyroid function tests

42. COMPLICATIONS
● Wound hemmorhage
● Wound infection
● Superior laryngeal N injury
● Recurrent laryngeal N injury
● Unilateral RLN injury
● Bilateral RLN injury
● Hypocalcemia
● Thyroid storm

43. POST OPERATIVE MANAGEMENT
● Thyroid hormone replacement
● Radioactive iodine treatment
● External beam radiotherapy and chemotherapy

44. RECENT ADVANCES
● Minimally invasive thyroidectomy
● Robotic transaxillary thyroid surgery
● Transoral thyroidectomy

45. THANK YOUTHANK YOU