Thyroidectomy

short description of thyroidectomy

1. Thyroidectomy -- S ubtotal, total and hemi thyroidectomy-- JISHNU.K.R FINAL MBBS

2. Preoperative preparation: Aims to make the patient biochemically euthyroid at operation. Carbimazole 30- 40mg per day is DOC. ‘ Block and replace’ regime. Alternative method by using β adrenergic blockers- propranalol 40mg TD or Nadolol 160mg OD

3. It is important to continue the drug β blockers for 7 days postoperatively. Less effective alternative is Iodine which produces a transient remission and may reduce vascularity .

4. Preoperative investigations: Thyroid function tests Laryngoscopy Thyroid antibodies Serum Ca estimation Isotope scan- before preoperative prepartion is necessary in patient with toxic nodular goitre if total thyroidectomy is not planned.

5. Extent of the resection depends on: The size of the gland The age of the patient Experience of the surgeon The need to minimise the risk of recurrent toxicity, And, wish to avoid postoperative thyroid replacement.

6. Types: Sub-total: about 8gms , or a tissue, size of pulp of finger is retained on lower pole on both sides and rest is removed. Commonly done in toxic thyroid, MNG. Total: entire gland is removed. Done in malignancy.

7. Near-total: both lobes except the lower pole which is very close to recurrent laryngeal nerve and parathyroid is removed. Here <2gm of tissue is left behind. Hemi: along with removal of one lobe, entire isthmus is removed. Done in benign disease of only one lobe, thyroid cyst, solitary nodule.

8. Technique: GA with endotracheal intubation and muscle relaxant. Patient in supine position, table tilted up 15 degree at the head end. Sand bag is placed under the shoulders and neck is extended. Incision: a gently curved skin-crease incision is made midway between the notch of the thyroid cartilage and the suprasternal notch.

9. The flaps are raised and fixed and the deep cervical fascia is divided in the midline. Middle thyroid veins ligated and divided. Ligate the branches of superior thyroid A individually. Inferior thyroid A ??

10. The recurrent laryngeal nerve is identified as it is intimately related to the terminal branches of the inferior thyroid A. Parathyroid glands are identified. The thymus is detached by serially dividing the inferior thyroid veins.

11. In subtotal: the isthmus is transected and the lobe resected obliquely from the medial and lateral aspect to produce a V shaped surface. Care is required to avoid devascularisation of parathyroid and injury to recurrent laryngeal nerve. If parathyroid is unavoidably excised or devascularised , it should be fragmented and auto transplanted immediately within the SCM muscle.

12. T otal thyroidectomy: avoids transection of thyroid tissue by complete excision of the gland including the pyramidal lobe with preservation insitu or auto transplantation of as many parathyroids as can be identified. The pretracheal muscles and cervical fascia are sutured and wound closed.

13. New technologies: Achievement of haemostasis: ultrasonic shears and enhanced bipolar diathermy. RLN identification: electrical stimulation.

14. Complications: Haemorrhage Respiratory obstruction RLN palsy and voice change Thyroid insufficiency Parathyroid insufficiency Thyrotoxic crisis Wound infection Hypertrophic scar Stitch granuloma.

15. Haemorrhage Tension haematoma deep to cervical fascia occurs due to reactionary h’age . Requires urgent decompression by opening the layers of the wound. Sub cutaneous haematoma require evacuation in the following 48hrs

16. Respiratory obstruction: Mostly due to laryngeal oedema. Other causes: tracheomalacia and trauma perioperatively . Try releasing tension haematoma and if it still persists an intubation should be done and kept for several days. Give steroids to reduce oedema. If necessary, tracheostomy.

17. RLN palsy and voice change: May be U/L or B/L. Injury to ext. branch of superior LN is more common and leads to loss of tension in the vocal cord with diminished power and range in the voice. Can be detected by postoperative laryngoscopy.

18. Thyroid insufficiency: Occurs within two years following subtotal thyroidectomy. This results from a change in the autoimmune response from stimulation to destruction of thyroid cells.

19. Parathyroid insufficiency: This is due to removal of parathyroid glands or infarction. Thyrotoxic crisis: Acute exacerbation of hyperthyroidism due to inadequate preoperative preparation. A dministration of iv fluids, cooling the patient with ice packs, O 2 , diuretics, digoxin, sedation and iv hydrocortisone. Specific Rx: Carbimazole 10-20mg 6 th hrly ; lugol’s iodine 10 drops 8 th hrly ; propranalol 1-2mg iv.

20. Wound infection: cellulitis- antibiotics; abscess- drained. Hypertrophic or keloid scar: intradermal injection of corticosteroid once monthly. Stitch granuloma: due to non absorbable suture material.

21. Postoperative care: About 25% develop transient hypocalcemia and oral Ca 1gm TD. For severe hypocalcemia : 10ml iv Ca gluconate 10% and alfacalcidol 1-2µgm daily. Lifelong follow up to detect recurrent thyrotoxicosis and thyroid failure.

22. Thank you..