What is the procedure for performing a parathyroidectomy?

Parathyroidectomy Procedure: Surgical Approaches and Techniques

Parathyroidectomy is performed through either bilateral neck exploration (BNE) or minimally invasive parathyroidectomy (MIP), with the choice depending on preoperative imaging localization and suspicion for multiglandular disease. 1

Preoperative Assessment and Preparation

• Imaging: Preoperative localization is essential for MIP

  • 4D-CT neck without and with IV contrast is the first-line imaging modality (sensitivity 79%, PPV 90%) 2
  • Sestamibi-SPECT scans are commonly used to identify single adenomas 3
  • Imaging is particularly crucial for reoperative cases to identify target lesions and postoperative changes 1

• Laboratory tests: Serum calcium and PTH levels should be measured before surgery to establish baseline values for intraoperative monitoring 1

Surgical Approaches

1. Bilateral Neck Exploration (BNE)

• Traditional standard approach where all four parathyroid glands are identified and examined
• Indicated for:
  • Discordant or nonlocalizing preoperative imaging
  • High suspicion for multiglandular disease (MGD)
  • Secondary hyperparathyroidism (typically involves multiple gland hyperplasia) 1

2. Minimally Invasive Parathyroidectomy (MIP)

• Unilateral operation with limited dissection targeting only the affected gland
• Requires confident preoperative localization of a single adenoma
• Benefits include:
  • Shorter operating times (average 44-56 minutes)
  • Faster recovery
  • Decreased perioperative costs
  • Smaller incision (typically 1-4 cm)
  • Can often be performed as outpatient procedure 1, 4, 3

Specific MIP Techniques

1. Open MIP (OMIP):

   • Small 2.5-3 cm incision directly over the localized adenoma
   • Direct visualization without endoscopic equipment 5

2. Video-Assisted MIP (MIVAP):

   • Uses endoscopic tools through a small incision
   • Better visualization of recurrent laryngeal nerve
   • Lower postoperative pain scores
   • Higher cosmetic satisfaction 5

3. Radioguided Parathyroidectomy:

   • Uses gamma probe during surgery after preoperative Tc-99m sestamibi injection
   • Helps confirm removal of hyperfunctioning tissue 6

Anesthesia Options

• Local/Regional Anesthesia with Sedation:

  • Anterior cervical block performed by the surgeon
  • Combined with moderate IV sedation
  • Allows for outpatient procedures (84-91% of cases can be completed this way)
  • Lower costs compared to general anesthesia 4, 3

• General Anesthesia:

  • Required for approximately 10-16% of cases initially planned for local/regional
  • Common reasons for conversion include:
    • Need for simultaneous thyroid surgery
    • Failure of intraoperative PTH to decrease appropriately
    • Technical difficulties related to recurrent laryngeal nerve protection
    • Patient comfort issues
    • Recognition of parathyroid carcinoma 7

Intraoperative Monitoring

• Intraoperative PTH (IOPTH) monitoring:
  • Blood samples taken before and 5-10 minutes after parathyroid resection
  • A drop of ≥50% from baseline confirms successful removal of hyperfunctioning tissue
  • If inadequate drop occurs, further exploration is necessary 3, 7
  • Essential for both MIP and BNE approaches to avoid surgical failures 5

Specific Surgical Procedures for Secondary Hyperparathyroidism

For patients with secondary hyperparathyroidism (common in chronic kidney disease), three main surgical options exist:

1. Subtotal Parathyroidectomy (SPTX):

   • Removal of three and a half glands
   • Leaves small remnant of parathyroid tissue

2. Total Parathyroidectomy (TPTX):

   • Complete removal of all parathyroid tissue
   • May lead to temporary hypocalcemia but reduces SHPT recurrence

3. Total Parathyroidectomy with Autotransplantation (TPTX+AT):

   • All parathyroid tissue removed, with portion reimplanted elsewhere
   • Common sites include sternocleidomastoid muscle, brachioradialis muscle, or forearm
   • Allows for easier management if recurrence occurs 1

Postoperative Care and Monitoring

• Calcium levels should be monitored postoperatively
• Transient hypocalcemia may occur in approximately 10% of patients
• Most patients can be discharged the same day after MIP (86-90%)
• Cure rates are excellent (98-100%) with proper patient selection 4, 5

Potential Complications

• Recurrent laryngeal nerve injury (rare: <1%)
• Transient hypocalcemia (approximately 10%)
• Persistent or recurrent hyperparathyroidism
• Bleeding or hematoma
• Infection (rare) 4, 5

Parathyroidectomy is a highly effective procedure with low morbidity rates when performed by experienced surgeons using appropriate patient selection and modern techniques.