Thyroid & Parathyroid

Thyroid

GOITRE

Assessment

• Single / multiple
• Hard /soft
• Fixed
• Nodes
• Horner’s

Thyroid nodules

• Palpable / U-S
• Palpable 3% F; 1%M
• U-S 45 %
• Malignant 5 to 10 % (solitary /  solid)

Aetiology

• Symmetrical / diffuse- Grave’s,hyper,eye signs
• Malignant - Young,male,rapid growth,fam  Hx,RT
• Toxic -  Grave’s / Plummer’s (toxic  multinodular)

Investigation

• TFTs (T3,T4,TSH)
• Thyroid  autoantibodies/CRP(thyroiditis)
• FNAC
• U-S  (solid/cystic;solitary/dominant  multi n)
• Isotope (10% ca in  solitary,solid,”cold”)
• CXR (thoracic inlet)

THYROIDECTOMY

History

• First thyroidectomy Albucasis in  Moorish Spain in 952 AD
• No progress until late 19 th C  when many reports of fatalities  from massive haemorrhage
• Kocher over 4000  thyroidectomies with mortality  falling from 50% to 0.2%

  ( Nobel prize 1909 )

W.S. Halsted

“ The extirpation of the thyroid  gland for goitre typifies, perhaps  better than any operation , the  supreme triumph of the surgeons’  art”

Indications for  thyroidectomy

• Cosmesis, anxiety, pt.  preference
• Toxicity (refractory to med Tx ,  Grave’s)
• Pressure symptoms  (plunging/stridor)-  Pemberton’s / Kocher signs
• Suspicion of ca

Thyroidectomy: extent of surgery

• Solitary nodule :lobectomy

ID RLN/protect SLN ; ID  parathy

• Multinodular: unilat or total  (15%recurrent goitre)
• Grave’s: unilateral  lobe/contalateral subtotal or  total (? eye signs)
• Toxic adenoma: lobectomy  (hot/solid)

Op in toxic goitre

Failed med Tx

radio-iodine unaccaptable(pregnancy within 2 years)

Large toxic goitre

Grave’s

Cardiac toxicity

Prep in toxic goitre :

   B blockers,antithy drugs,Lugol’s

   Lugol’s (K iodide 0.3 mls BD x 10 days)

Preparation

Dental chair position

Extend neck (not hyper-extend)

Pad between shoulders

Symmetric incision

Assistance / retraction

Head-lamp

Thyroidectomy : scar

The most important scar in  surgery

Crease line

Close in layers

4/0 nylons and steristrips

0.5% plain marcaine

Toxic goitre	Mediastinal goitre
Render euthyroid Propranol Lugol’s iodine +/-    K iodide 0.3 mls BD x 10 days Trend is towards total   thyroidectomy Incision / scar The most visible scar Crease-line ( Langer ) Symmetric Divide platysma slightly off-line Perfect closure….4/0  nylons+steristrips Remove sutures at 48 hours Massage scar	Deliver into neck First I.D. RLN Slow pressure fingers / “spoon” Rarely sternotomy ( manubrial  split )

Complications

Death

Bleeding / haematoma

Nerve injury

Hypoparathyroid

Infection

Thyroid storm / toxic

scar

Prevantive Measures

• Expertise / volume
• Set-up ; light / head-lamp
• I.D. structures
• Haemostasis
• No powered dissection  posteriorly
• Minimum lobectomy

Bleeding / Haematoma

• 1 in 150
• First 6 hours
• Swelling / pain / anxiety
• Superf(sub platysma);  deep(under straps)                                                          
• Bedside decompression
• Exploration

Exploration for  bleeding

• No bleeding point
• Ant. Jugular veins
• Sup. pole vessels
• Berry’s ligament
• Thyroid remnant

Prevention of bleeding

Minimum lobectomy

If bleeding remnant

      - oversew

      - tamponade to trachea

• ligate ITA in continuity
•  

Laryngeal nerves

Pre-op laryngoscopy

Previous neck surgery

History of hoarseness

Nerve injury related to surgeon         Volume

1-9      cases………..1.5%

10-29  cases………..0.5%

30-100 cases……….0.8%

> 100   cases……….0.4%

  p<0.05% , Chi squared

Hypoparathyroid

Temporary 10% ; permanent 1%

C/O : tingling mouth  / tongue

             anxiety…hyperventilation increases

             spasm / tetany

             Chvostek / Trousseau

Treat : acute  :   Ca gluconate   10 ml-10%-10min

                 chronic: 1 alpha Vit D    0.25 mcg/d

                                 sandocal         400 mg QDS

Parathyroidectomy - technical

Identify all 4 parathyroids

Areas to search :    

• ( inferior)
• racheo-oes groove
• thyro-thymic tongues
• sub thyroid capsule
• inf. undescended (above sup.)
• carotid sheath
• mediastinum

Hypoparathy :  Prevention

Know locations (85% within 1  cm of  ITA /RLN cross-over)

Preserve every parathy. as if  pt.’s last

Care with blood supply from  ITA

AutoTx if doubtful viability            

Phase 1 : auto-Tx in 12

        Auto-Tx 12 pts. (9 F;3 M )

Ca++              PTH(Tx)              PTH(contra)              ratio

2.37                 200                               49                                          4:1

2.06*                 25                               24                                          1:1

2.43                      1700                               63                                   27:1

2.13                        340                               54                                   14:1

2.17                          33                                 9                                          4:1

2.29                          19                               18                                          1:1

     * ? Graft function

     forearm sestamibi scan in 4 : all negative

Reported complication  rates

   Actual complication rates difficult to compare due to:

    wide ranges (RLN 3-18% in re-op.)

    pathology     (toxic / ca.) 

    early v late*  (RLN 8.6 v 0.3%

                   SLN 1.3% v 0 ;hypopara 9.6 v 0.7% )

  *Rios-Zambudio et al, Ann Surg 2004,240:18-25

Nerve injury

RLN

SB-SLN (ELN )

Vagus

Symp chain / Stellate ganglion

Prevention : summary

Adequate numbers

Head-up

Head-lamp

Nerve anatomy

Haemostasis

Parathyroids

6 hr. recovery

Incision=scar

Euthyroid in toxic

Deliver plunging+/- split

THYROID CANCER

Epidemiology

• Rare with abN TFTs
• 1 in 100,000 M ( x2 in F )
• Good Px papillary to aggressive  anaplastic
• Papillary/follicular 12%  local/distant recurrence
• 85% 10 yr survival

Risk factors

Previous RT

Endemic goitre

Hashimoto’s (lymphoma)

Adenoma

Familial

FAC

Papillary	Follicular	Medullary	Anaplastic
80 % Nodal spread Lobectomy <1 cm Total > 4 cm Node dissection if N+ or high  risk High risk: male,>45,>4  cms,extra-capsular F/U : TSH,isotope,TG	15% Blood spread FNAC ? ca v adenoma Frozen ? capsular invasion Lobectomy <1 cm ( <2 cm in F  < 45) Total >4 cm ; vascular  invasion;Hurtle cell    completion thyroidectomy after  histology	3% 80% sporadic 20% familial : MEN 2 (PPT) / Familial without other endocrine Positive stain for calcitonin and CEA Solitary nodule or nodes Calcitonin = flushing and diarrhoea Total thyroidectomy + central nodes Parathyroidectomy if enlarged in MEN 2 Prophylactic thyroidectomy in familial with RET mutation (age 5 - 7) Calcitonin as marker of recurrence	Surgery not indicated     No RT (?CT)    Dismal Px

Lymphoma

   Associated with Hashimoto’s

   CT

   Excellent Px

Post-thyroidectomy radioiodine ablation

No r.a. Iodine:

   Complete excision,unifocal,<1cm,no extrathyroid,Node negative,no mets

Possible r.a. Iodine :

   Incomplete excision,unfavourable histology,>2 cms,no node dissection,age<18

Always r.a.iodine:

   High risk,incomplete resection,>4 cms,extra-capsular, mets

HYPERPARATHYROIDISM

Calcium Regulation

99% of body calcium in skeleton

Miscible Pool: 40% bound to protein, 13% complexed w/ anions, 47% free ionized

PTH: Increased Ca, Decreased PO4, Increased Vitamin D

Vitamin D: Increased Ca, Increased PO4, Decreased PTH (slow)

Kidney, Bones, GI Tract

Hypercalcaemia

Hyperparathyroidism

• Primary
• Tertiary

Cancer

• Breast, prostate, kidney and thyroid
• Multiple myeloma

Sarcoidosis

Vitamin D intake

Hyperparathyroidism

• 85% solitary adenoma
• 15% hyperplasia or multiple adenomata
• <1% parathyroid carcinoma
• Primary HyperPTH: Most common; postmenopausal women
• Secondary HyperPTH: Usually renal failure
• Tertiary HyperPTH: Chronic Renal Failure; low or normal Ca, irrepressible PTH

Aetiology

Primary                            (   PTH, normal or   Ca 2+ )

• Adenoma                            90%
• Hyperplasia                            10%
• Carcinoma                     <               0.1%

Secondary              (  PTH appropriate to low Ca 2+ )

• Chronic Renal Failure
• Vitamin D Deficiency

Tertiary

• Continued excess PTH secretion following prolonged secondary hyperparathyroidism.

Presentation

• Usually asymptomatic
• Fatigue and weakness – up to ½ resolve
• Bone and joint pain, stones and hematuria   (Reflect decreased bone density & nephrolithiasis)
• Osteitis Fibrosa Cystica (Brown tumor) and Nephrocalcinosis rare
• Calciphylaxis
• Ca=2.2-2.4 mmol/l
• Constitutional: fatigue, wt loss, anorexia
• Musculoskeletal: pain, weakness
• Renal: colic, hematuria
• GI: Pancreatitis, constipation, PUD, nausea
• Neuro: H/A, memory loss, psychosis, insomnia
• Skin: pruritus, brittle nails
• Slow progression
• 75% of asymptomatic patients remain symptom free
• Risk factors: XRT, chronic Lasix, chronic lithium, family h/o MEN

Diagnosis

Elevated serum Ca X 3 (ionized best)

Elevated PTH

Other:

• Albumin
• Alkaline Phosphatase
• Phosphate
• Urea and creatinine
• 24-hour urine Ca
• Bone Mineral Density

Localization

4 glands in 87% of patients; range 2-6 glands

Internal carotid artery to AP window

Superior parathyroid glands within 1 cm of RLN piercing cricothyroid membrane

Location of Ectopic glands:

• Paraesophageal (28%)
• Mediastinum (26%)
• Intrathymic (24%)
• Intrathyroidal (11%)
• Carotid sheath (9%)
• High cervical (2%)

Investigations

• Ultrasound
• Sestamibi scan
• 
  • 1989: Cardiac imaging, Technetium derivative
  • SPECT imaging
  • False Positives: Thyroid nodules
  • False Negatives: Small adenomas, hyperplasia
  • Cheap
• CT
• FNA
• MRI
• Angiography w/ or w/o selective venous sampling (Angioablation)

Medical Management

Q6months- Ca, Cr, U/A, PTH

Q12 – bone density

Severe Hypercalcemia:

• Saline-furosemide diuresis
• Bisphosphonates (onset of action 24-48h)
• Calcitonin (immediate onset)
• Hemodialysis

Surgical Management

95% Success Rate

50-85% in renal failure

1% morbidity

Benign clinical course of hyperparathyroidism

NIH Guidelines (1990)

• Symptomatic HyperPTH
• Serum Ca 1-1.6 mg/dL above normal
• H/o life-threatening hypercalcemic event
• ClCr <70% of expected
• Kidney stones on radiograph
• Elevated urine Ca (>400 mg/dL)
• Z-score>2
• Patient requests surgery
• Consistent followup unlikely
• Complicating comorbid condition
• Age<50 yo

Renal failure (Unresponsive to medical tx)

• Renal osteodystrophy/pathologic fractures
• Intractable bone pain/pruritus
• Calciphylaxis

New Tools of the Trade: Minimally Invasive Surgery

• Pre-operative Sestamibi
• Intraoperative rapid PTH (50%, 80%)
• Hand-held gamma probe
• Methylene blue

Adenoma

• Unilateral vs. Bilateral Exploration
• rPTH vs. Frozen Section

Hyperplasia/Multiple adenomata

• Subtotal – less hypocalcemia
• Subtotal w/ autotransplantation – MEN, Renal Failure
• Total w/ Cryopreservation – up to 1 year

Autotransplantation

• Iced saline bath
• 20-30 mg; 10-20 1-2 mm slices
• SCM vs. Brachioradialis
• Pockets marked with clips
• Up to 50% failure rate

Surgical Complications

• Failure: missed ectopic adenoma, incomplete resection in multi-gland dz.
• Hypocalcemia (20-30%)- Wait for appearance of symptoms
• TVC paralysis (<1%)
• Hematoma

Multiple Endocrine Neoplasia

MEN I

• Moderate-severe hyperPTH in 85%
• Zollinger-Ellison, prolactinomas
• Auto Dominant, MEN1(tumor suppressor), Chromosome 11

MEN IIa

• Mild hyperPTH in 70%
• Medullary Carcinoma 100%
• Pheochromocytoma
• Auto Dominant, RET proto-oncogene

Parathyroid carcinoma

• Hi PTH, palpable neck mass, Hi Ca post-op
• Regional/distant mets in 25-30%, Local recurrence 30%
• Surgery: Ipsilateral thyroid lobe, skeletonization of RLN, paratracheal nodes