SURGERY OF THYROID AND PARATHYROID GLAND.pptx

surgery of thyroid and parathyroid

1. SURGERY OF THYROID AND PARATHYROID GLAND Presented by Dr. Vanshika Suman Guided by- Dr. R. Teharia (MS) Asst Prof

2. HISTORY In 1646, the first thyroidectomy using scalpels was done Albert Theodor Billroth , reduced the thyroidectomy mortality rate from 40% to 8% Theodor Kocher was the first surgeon to systematically ligate the inferior thyroid artery, which significantly reduced the risk of haemorrhage . He introduced the collar incision. He was acknowledged as the ‘father of modern thyroid surgery’.

3. TOTAL LOBECTOMY - Removal of one lobe of thyroid along with the thyroid isthmus THYROID ISHTHMUSECTOMY - Excision of the thyroid isthmus, often with the pyramidal lobe of the gland. SUBTOTAL THYROIDECTOMY - Bilateral excision of more than one half of the thyroid gland on each side together with the isthmus. NEAR-TOTAL THYROIDECTOMY/ DUNHILL’S THYROIDECTOMY - Excision of 90% of the gland TOTAL THYROIDECTOMY - Excision of the entire gland

4. SURGERY FOR BENIGN DISEASE In patients with a single nodule- Total lobectomy is done Bilateral multinodular goitre - Total thyroidectomy Graves’ disease- Total thyroidectomy

5. SURGERY FOR MALIGNANT DISEASE For patients with T3 and above differentiated thyroid cancers (DTC), medullary carcinoma of the thyroid, poorly differentiated thyroid cancer, multinodular glands, multifocal cancer, evidence of extrathyroidal extension or overt nodal metastases- Total thyroidectomy is the procedure of choice. Uninodular DTC, without extra thyroid extension or metastases- TL results in oncological outcomes equal to TT

6. SURGICAL TECHNIQUE FOR STANDARD THYROIDECTOMY Position - Supine position, with shoulder support and head ring to allow maximum extension of the neck. Incision - Kocher collar incision

7. Approach - - Tissues are divided through the subcutaneous fat and platysma - Flaps are raised in the immediate subplatysmal plane upto a level above the thyroid cartilage and down to the suprasternal notch. - The anterior jugular veins are identified and protected during dissection. - The investing cervical fascia is then incised in the midline and opened to the level of thyroid cartilage and the sternal notch. - Division of strap muscles- sternohyoid muscle is first dissected and retracted laterally to expose the underlying sternothyroid muscles and the anterior surface of the thyroid gland.

8. Elevation of subplatysmal flaps Incision of cervical fascia Division of strap muscles

9. Dissection begins at the superior pole - Each branch of the STA is individually clamped and divided as close to the capsule of the upper pole as possible to avoid injury to the EBSLN The nerve is located posteromedial to the superior thyroid artery and curves medially to enter the cricothyroid muscle near the upper pole of the thyroid gland. The superior parathyroid gland is identified adjacent to the posterior capsule of the superior pole Joll’s triangle Position of superior parathyroid

10. Dissection of the lateral aspect of the gland - Middle thyroid veins are ligated and divided to allow delivery of the gland and access to the paratracheal areas The fascia surrounding the gland is dissected and the thyroid is slowly mobilized, allowing visualization of the trachea-esophageal groove. Mobilization of the lateral aspect of the gland

11. Dissection at the inferior pole - - The inferior thyroid veins are individually ligated and divided and the anterior surface of the trachea is exposed. - Trachea is identified, and a safe plane of dissection is developed separating the inferior pole from the trachea - The recurrent laryngeal nerve can be damaged at this point

12. RECURRENT LARYNGEAL NERVE Lateral approach : Nerve is identified in the Beahrs triangle - - Superiorly by inferior thyroid artery - Medially by RLN - Laterally by common carotid artery

13. Inferior approach - -Identification of the RLN is best achieved through an inferior approach in a space defined by Lore as the retrolaryngeal node triangle . -This triangle is bounded by the trachea medially, the carotid sheath laterally, and the undersurface of the retracted inferior thyroid pole superiorly. Extracapsular dissection technique is then used on the gland preserving the recurrent laryngeal nerve and two parathyroid glands. The assistant applies gentle but firm gradual sequential upward and medial traction using a swab (a technique known as ‘creeping’), to elevate the lobe from the thyroid bed as the capsule is being exposed. Vessels are ligated directly on the surface of the thyroid gland capsule.

14. The RLN should be followed to its laryngeal entry at the level of the cricoid cartilage, passing under or through the Berry ligament and entering the larynx deep to the inferior constrictor muscle. The nerve may divide into multiple branches before entering the larynx. The ligament is dissected using fine bipolar diathermy. The blades of the bipolar should be resting on the thyroid gland and away from the nerve. Once the diathermy has been performed, the ligament is divided with a size 15 blade scalpel. This provides the best accuracy and reduces the risk of injury.

15. When the lobe is mobilized, and key structures are identified, the isthmus can be transected close to the contralateral side. The pyramidal lobe should always be identified, dissected and excised together with the thyroidectomy specimen. Total Lobectomy

16. CLOSURE Wound is washed with normal saline. Hemostasis is achieved Check for parathyroid glands and RLN to ensure that they are intact anatomically Drain Subcutaneous tissues and skin is closed in layers

17. POST-OPERATIVE CARE Head up position ( 45 degree) Early mobilization to prevent VTE Steroid/antibiotic/analgesic treatment Drain removal- removed if the volume is less than 20ml at 24 hours or 10ml at 8 hours Post-operative vocal cord check

18. PARATHYROIDECTOMY

19. The parathyroid glands have a caramel color, fat lobules are yellow and the lymph nodes have pinkish discoloration Parathyroid adenoma Hyperplasia of gland a- lymph node b- parathyroid c- fat lobule

20. The main indications for four-gland exploration are: - Secondary or tertiary hyperparathyroidism with renal failure - Suspected MEN syndromes - As extension of single-gland surgery when PTH levels do not fall - Negative imaging localization studies

21. Location of Inferior parathyroid glands - They tend to be larger and more anterior Their location may be variable They are found adjacent to the inferior pole of the thyroid gland or within a tongue of thymic tissue inferior to the thyroid, the thyrothymic ligament. Commonly, the inferior glands may be located anterior and slightly medial to the juxtaposition of the inferior thyroid artery and RLN.

22. Location of the superior parathyroid glands : Located adjacent to inferior cornu of the thyroid cartilage, close to the RLN, cranial to the branch of the ITA Exposure of the posterior aspect of the thyroid lobe is made by displacing the gland inwards and retracting the jugular-carotid bundle They are found immediately superior to the junction of the RLN and the ITA

23. The parathyroid glands derive their blood supply from the inferior thyroid artery, but the superior parathyroid glands also may derive their blood supply from the superior thyroid artery To locate the parathyroid glands, dissection and identification of the recurrent laryngeal nerve and the inferior thyroid artery with its branches is important

24. APPROACH : A low transverse cervical (Kocher) incision is made two finger breadths above the suprasternal notch, and is carried down through the platysma. After incising the platysma, the cranial skin–platysma flap is dissected upward to the notch of the thyroid cartilage, and the caudal skin-platysma flap is dissected inferiorly to the suprasternal notch. The midline raphe of the strap muscles is identified and separated from the thyroid notch to the suprasternal notch, which allows the sternohyoid muscles to be retracted laterally. The sternothyroid muscle is separated over the thyroid lobe on the side of the neck to be explored first. The thyroid lobe on the side being explored is retracted anteromedially to access the potential space posterior to the thyroid lobe. Middle thyroid venous tributaries are divided and ligated.

25. Dissection of the superior parathyroid glands should be initiated at the outermost tip of this gland to prevent injury to the parathyroid vessels, which usually ascend from arterial anastomoses that originate from the inferior thyroid artery. The dissection of the inferior parathyroid gland should begin at the caudal end of the parathyroid, because the vascular pedicle generally enters on the upper or cranial side of the inferior parathyroid gland. Suspected devitalization of a normal parathyroid gland during dissection generally requires that it be auto transplanted within cervical muscle.

26. After it is identified, the abnormal gland is removed and sent for pathologic analysis. A thorough search is conducted to locate the second gland on the same side; if found, it too is removed and sent for pathologic determination. Subtotal (3.5 gland) parathyroidectomy.

27. In contrast to normal parathyroid tissue, parathyroid adenomas appear rust red or beefy red in situ. They may be mottled or variegated in their coloring and usually lighten on resection. Hyperplastic glands generally appear darker than adenoma and are usually a dark rust, brown, or chocolate color that more closely resembles the color of thyroid tissue. Failure to identify a missing gland suspected to be an adenoma—or in the case of hyperplasia, failure to locate all glands—mandates a thorough dissection in an effort to locate abnormally located or ectopic parathyroid tissue. Surgical dissection should address all areas accessible through a cervical approach, including the removal of thymic tissue within the superior mediastinum, examination of the retroesophageal space and carotid sheath to the hyoid, and thyroid lobectomy (lobotomy) if necessary.

28. COMPLICATIONS INFECTION: - SSI is rare in thyroid and parathyroid surgery, occurring in less than 1% cases - Superficial wound infections are treated with local wound care and oral antibiotics. -Deep wound require incision and drainage with wound culture, in addition to i.v. antibiotics and investigation for the source, which is often a missed aerodigestive injury.

29. 2. SEROMA: - The incidence is low, 1–7% of cases. - Seromas are more likely to occur after surgery for a large goitre or a total thyroidectomy. - In most cases, seromas are managed conservatively with observation and by reassuring the patient. - When seromas are painful or lead to tightness, aspiration of the fluid using sterile technique is done. The aspirated fluid should be sent for culture and antibiotics should be started. In the majority of patients, seromas resolve over 6–8 weeks.

30. 3. HAEMATOMA: - Occurs within the first 6–12  hours after surgery - It can be superficial (above the strap muscles) or deep (below the strap muscles). It can cause venous and lymphatic congestion leading to eventual airway compromise. - Decompression and evacuation of clot should be done. The incision is released and the strap muscles are incised to release pressure from the haematoma . - The patient is then returned to the operating theatre for haematoma evacuation, identification and control of the bleeding source. After achieving complete haemostasis , the wound is closed again.

31. 4. RLN INJURY: - Pre-operative laryngoscopy should be performed on all patients to document baseline vocal cord function - Intra-operative direct visualization of the recurrent laryngeal nerve (RLN) lowers the rates of temporary and permanent RLN injury rates and is considered as the gold standard. - Intra-operative neural monitoring (IONM) is an important complement to visualization of the nerve. IONM have shown a trend towards lower RLN injury rates but statistical proof is lacking. - Post-operative laryngoscopy should be done to look for postoperative glottic function and for early identification of Vocal cord palsy. - In the first 3 months, cordal injections can enhance contact between the vocal cords and improve swallowing, voice and cough. -If the injury is permanent, procedures like thyroplasty and medialization laryngoplasty can be done. -Reinnervation is another option that can be done by mobilizing a functioning nerve, typically the ansa cervicalis to the distal RLN stump. It may take several months to regain voice function after this procedure.

32. 5. INJURY TO EXTERNAL BRANCH OF SUPERIOR LARYNGEAL NERVE: - It results in voice changes characterized by loss of high tone and pitch volume and fatigue after extensive use - A precise surgical technique with careful superior pole dissection and ligation of the superior pole vessels on the gland itself is important - Speech therapy

33. 6. HYPOPARATHYROIDISM: - For patients with thyroid cancer, substernal goitre, Graves’ disease and reoperation, hypoparathyroidism is a significant concern. - Pre-operative Vitamin D, serum calcium and PTH evaluations are helpful. - If the vitamin D is low, replacement before surgery is helpful - Meticulous dissection with preservation of the parathyroid glands and their blood supply is required to avoid hypoparathyroidism. - Post-operatively, serum calcium levels can be checked to determine the need for calcium supplementation. - Hypoparathyroidism can be temporary, less than 6 months post-surgery (8–30%), or permanent in more than 6 months post-surgery (1.7–3.5%).

34. 7. AERODIGESTIVE INJURY: - In patients with known thyroid cancer with tracheal or oesophageal invasion, a thorough workup including imaging and endoscopy should be completed pre-operatively. - Tracheal injuries can be small or large. Small injuries can be repaired primarily with absorbable sutures. If primary closure is not possible, segmental tracheal resection may be performed or a tracheostomy tube is placed. - Oesophageal repair includes debridement of the tissue edges with two-layer closure of the mucosa and muscle separately. A strap muscle may be used to buttress the repair.

35. 8. HYPOTHYROIDISM: - The starting dose for levothyroxine is 1.6–1.8mcg/kg/day and is titrated based on thyroid function tests thereafter. - For patients who have undergone lobectomy, there is a 15–50% risk of abnormal thyroid function after surgery with the need for levothyroxine. -Hashimoto’s disease, higher TSH or lower free T4 or a smaller remaining lobe increase the likelihood of requiring T4 supplementation.

36. 9. HYPERTHYROIDISM: - Patients with hyperthyroidism secondary to Graves’ disease, toxic multinodular goitre or a toxic nodule are at risk for development of thyroid storm. -Multiple systems are affected in thyroid storm – cardiopulmonary, thermoregulatory, metabolism, neurological and gastrointestinal. - Tachycardia, dysrhythmia (usually atrial fibrillation), high fever and respiratory changes are the most common symptoms. - Cooling the patient, administering a beta blocker and hydrocortisone are initiated. - Antithyroidal medication, PTU or carbimazole is also started. - A dose of Dantrolene in given in this situation because the symptoms of malignant hyperthermia and thyroid storm are difficult to differentiate. - Post-operatively, patients with thyroid storm need close monitoring.

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