Complications - Hemithyroidectomy

Bleeding

In the event of massive intraoperative bleeding (e.g., from Kocher's vein or the inferior thyroid artery), tamponade is initially performed, and continuous suction is used to identify the vessel for clamping and ligation.

Note: For every thyroid procedure, it is recommended to check for hemostasis under PEEP ventilation before wound closure. 

Detection of Signal Loss in IONM (Intraoperative Neuromonitoring)

If it occurs on the first side of a planned bilateral resection, the resection of the contralateral side should be avoided to prevent the risk of bilateral recurrent laryngeal nerve palsy.

Hypoperfusion or Accidental Removal of a Parathyroid Gland (PG)

Typically, autotransplantation is performed after histological confirmation of the organ in 1 mm³ cubes into a pocket of the ipsilateral sternocleidomastoid muscle (do not forget documentation!).

Prophylaxis:

In addition to the gold standard of visual identification, at least in complex cases, an additional detection method with spontaneous or induced fluorescence is recommended (autofluorescence, ICG fluorescence, PT-EYE).

An assessment of the vascularization or devascularization of the parathyroid gland is only achieved with ICG fluorescence angiography. 

Tracheal Injury

Immediate suturing if possible, suture coverage with additional material (pericardium, pleura, sternocleidomastoid muscle, fleece-bound tissue adhesive), possibly stent, peri- and postoperative antibiotic therapy 

Esophageal Injury 

in extensive tumor or goiter surgeries, direct suture, antibiotics, drainage

Pleural Injuries/Tension Pneumothorax (in deep cervical resection)

Suture, possibly chest drainage

Recurrent Laryngeal Nerve Palsy/Vocal Cord Paralysis

Incidence

• 1 - 2%, in revision surgeries 2 - 8%
• Patients with thyroid malignancy have the highest risk of permanent recurrent laryngeal nerve palsy.

Cause

• mostly intraoperative stretching and compression of the recurrent laryngeal nerve (RLN) with a good prognosis and recovery of vocal cord function within days to weeks
• rarely continuity disruption
• compression injury after postoperative bleeding
• intubation-related non-neural impairments of vocal cord mobility: Not only intraoperative manipulations can damage vocal cord function, but also endotracheal intubation: incorrect positioning of the cuff (e.g., within the larynx), extubation with a blocked cuff, rough positioning of the head with the tube in place. Injuries to the vocal cords such as compression injuries, mucosal injuries, hematomas up to dislocation of the arytenoid cartilages are possible.

Consequences

• incomplete closure of the vocal cord on the affected side
• hoarseness, swallowing disorders, and respiratory impairments, especially in bilateral paralysis due to significant narrowing of the glottis. The primary concern is securing the airway, which may necessitate the placement of a tracheostomy.
• in symptomatic vocal cord paresis, speech therapy voice training

Prophylaxis

• Avoidance of recurrent laryngeal nerve palsy is considered a quality feature of the surgery.
• Preventing damage through precise anatomical knowledge with possible variations of nerve course, as well as careful visual representation and dissection to safely preserve the nerve.
• Use of neuromonitoring to identify the nerve and detect functional damage that may not be visually apparent.
• In the event of a signal loss on the first-operated side, consecutive suspension of resection on the opposite side.
• To preserve the vocal cord nerve, the following also contribute:
  1. so-called microdissection technique using optical instruments (magnifying glasses)
  2. the use of gentle hemostatic procedures (bipolar coagulation, vascular clips, "vessel sealing", ultrasonic dissection) 

Superior Laryngeal Nerve Damage

• The superior laryngeal nerve is a branch of the vagus nerve, which divides medially to the carotid artery into a motor external branch for motor innervation of the cricothyroid muscle and a sensory internal branch for the laryngeal mucosa.
• The external branch of the superior laryngeal nerve crosses, recrosses, or intersects the polar vessels in close proximity to the upper thyroid pole.
  
  
  • A lesion of this nerve branch can result in dysphonia with reduced vocal performance in terms of reduced vocal range and rapid voice fatigue.
  • The special anatomy should be taken into account by a capsule-close and gentle dissection of the upper thyroid pole.
  • Use of EBSLN monitoring in thyroid surgeries with difficult anatomy and in patients with high vocal demands. 

Basic information about intraoperative neuromonitoring can be found at:Link IONM

Sympathetic Nerve Damage

Rare complication in very large goiters or revision surgeries, evident as Horner's syndrome (partial ptosis, miosis, and facial anhidrosis)

Dysphagia

• Causes: arytenoid trauma after intubation, surgical trauma to the straight neck muscles or the cricothyroid muscle, changes in laryngeal blood flow, scar and adhesion formation with disturbance of hyoid mobility or laryngotracheal fixation to soft tissues and skin, psychogenic, damage to the extrinsic perithyroidal nerve plexus
• Therapy: mostly self-limiting, lateralization of the straight neck muscles

 Postoperative Bleeding

• Incidence (1 - 2%): Most postoperative bleedings occur within the first 6 hours after the procedure. Data show that 54% of all patients in thyroid and parathyroid surgery experience nausea and vomiting for more than 24 hours postoperatively and are at increased risk of postoperative bleeding during this phase. A significant risk of postoperative bleeding (about 20%) also exists beyond the 24-hour mark.
• Risk factors: use of anticoagulants, coagulation disorders, extensive resections, older patient age, male gender, revision surgery
• Prevention through meticulous intraoperative hemostasis and careful surgical technique. At the end of the operation, Valsalva maneuver and adequate blood pressure to check for blood dryness. Calm, uneventful emergence and extubation.
• Postoperative bleeding in thyroid surgery is a typical complication that can lead to a life-threatening situation. In arterial bleeding, blood enters the neck compartment under high pressure and can lead to compression, swelling, intubation-requiring respiratory distress, and asystole due to vagal pressure.
• Initial signs of bleeding: cervical pressure and tightness, muffled speech, swallowing difficulties. In case of sweating, shortness of breath, stridor, tachycardia, and hypotension, immediate surgical revision is necessary. Laboratory tests and ultrasound are not reliable diagnostic measures for detecting bleeding and should be deferred or omitted due to the acuteness.
• Therapy: Securing the airway takes precedence, but timely transfer to the operating room for orderly reintubation and revision under sterile conditions is preferable. Mucosal swelling in the larynx and trachea can significantly complicate intubation, making emergency tracheotomy necessary.
• Asymptomatic hematomas without significant increase in neck circumference should be treated conservatively, but close monitoring of the patient is required to intervene at any time.

Hypoparathyroidism

Common complication after bilateral thyroid surgeries, revision surgeries, or central cervical lymphadenectomy. Defined as a laboratory diagnosis with PTH < 15 pg/ml and simultaneously normal, low normal, or decreased serum calcium (protein-corrected). For early detection of postoperative hypoparathyroidism, serum calcium and intact parathyroid hormone should be determined immediately postoperatively or on the morning of the first postoperative day. Calcium on the first postoperative day alone does not correlate with the prognosis regarding the development of hypoparathyroidism.

Incidence

• in thyroidectomy transient up to 33.6%, permanent around 10%
• In transient hypoparathyroidism, parathyroid function normalizes within the first 6 months postoperatively.
• increased frequency in thyroid malignancies and Graves' disease

Cause

• accidental removal of one or more parathyroid glands Note: In about 7% of cases, parathyroid glands are found on the surgical specimen!
• circulatory disorders due to injury to the vessels supplying the parathyroid glands, devascularization of the parathyroid glands, especially through extensive exposure of the RLN or proximal ligation of the inferior thyroid artery. In central cervical lymphadenectomy, the blood supply to the lower parathyroid glands is particularly at risk.
• If fewer than 2 or 3 parathyroid glands are preserved, the risk of permanent hypoparathyroidism increases significantly.

Prevention

• Thyroid capsule-close vascular interruptions to avoid devascularization of the parathyroid glands.
• Secure identification of the parathyroid glands and capsule-close dissection, often pedicled on a branch of the inferior thyroid artery.
• Gentle dissection using so-called microdissection technique with optical instruments (magnifying glasses).
• Use of gentle hemostatic procedures (bipolar coagulation, vascular clips, "vessel sealing", ultrasonic dissection)
• In addition to the gold standard of visual identification, at least in complex cases, an additional detection method with spontaneous or induced fluorescence is recommended (autofluorescence, ICG fluorescence, PT-EYE).
  
  Autofluorescence: Parathyroid gland tissue emits a weak but specific fluorescence signal when stimulated with near-infrared light (wavelength often 785 nm). No dye is needed. Real-time display during surgery, special camera required.
  
  Indocyanine green (ICG) fluorescence angiography: Intravenous injection of indocyanine green (ICG), a fluorescent dye. ICG binds to plasma proteins and shows vascularized structures. The parathyroid glands become visible due to their particularly high vascular density with a special camera for near-infrared light (NIR light). Allows assessment of gland perfusion → prognosis of postoperative function.
   
• autotransplantation of parathyroid glands with impaired blood supply after histological organ confirmation (in 1 mm³ cubes in a pocket of the ipsilateral sternocleidomastoid muscle; do not forget documentation!).
• Basically, every parathyroid gland should be treated as if it were the last!

Therapy

• In case of postoperatively inadequately reduced parathyroid hormone (< 15 pg/ml), oral medication with calcium (e.g., calcium carbonate up to 3 x 500 mg/d; calcitriol 2 - 3 x 0.25 - 1 µg/d) should be initiated. If concomitant therapy with proton pump inhibitors is present, calcium citrate can be switched to. The medication can be supplemented with additional magnesium administration, as serum magnesium concentration is also reduced in hypoparathyroidism. In case of persistent symptoms under maximum oral medication, temporary intravenous therapy may be required.
• If the patient is discharged with high-dose calcium and vitamin D medication, regular monitoring and early adjustment/reduction of medication should be performed to avoid iatrogenic hypercalcemia. Avoidance of nephrotoxic hypercalcemia by setting serum calcium below 2.3 mmol/L. Higher serum calcium levels lead to increased urinary calcium excretion and suppression of parathyroid gland function with low or subnormal PTH.

Infections

Incidence

• 0.3 - 2.9%
• Wound infections usually occur as secondarily infected hematomas, abscesses can occur.
• With good wound management in addition to antibiotic treatment, infections generally do not cause major difficulties.
• Hematogenous spread and septic course are exceptions. In deeper cervical phlegmon, extensive and possibly repeated debridement is required.

Chyle Fistula/Chylothorax

Injury to the thoracic duct in large goiters with retrosternal extension, or when lymph nodes in the lateral neck triangle are removed.

Diagnosis/Therapy: conservative measures (drainage, compression bandages, total parenteral nutrition, special enteral diet); lymphangiography and possibly embolization of the thoracic duct

Extremely Rare Complications

• A potentially life-threatening early postoperative fulminant infection spread with mediastinitis can be triggered especially by group A β-hemolytic streptococci. Rapid diagnosis and therapy with wound opening, wound swab, and targeted antibiotic therapy are required. Risk factors include diabetes, immunosuppression, obesity, sternotomy, and long operation duration (> 2 - 3 hours).
• Injury to the accessory nerve or phrenic nerve in the lateral neck triangle