Overview
Definition:
Sestamibi-guided focused parathyroidectomy is a minimally invasive surgical approach for primary hyperparathyroidism, utilizing technetium-99m sestamibi scintigraphy to localize the hyperfunctioning parathyroid adenoma prior to and during surgery, enabling precise excision of only the abnormal gland(s).
Epidemiology:
Primary hyperparathyroidism affects approximately 1-4% of the general population, with adenomas accounting for 80-85% of cases
Sestamibi-guided surgery is indicated in a significant proportion of patients with localized adenomas, aiming to reduce operative time and morbidity.
Clinical Significance:
This technique significantly improves surgical success rates for primary hyperparathyroidism by accurately identifying the location of abnormal parathyroid tissue, thereby facilitating a less invasive, focused approach
This translates to shorter operative times, reduced neck manipulation, faster recovery, and fewer complications compared to traditional bilateral neck exploration, making it a cornerstone for efficient surgical management of hyperparathyroidism and crucial knowledge for surgical residents preparing for DNB and NEET SS exams.
Indications
Indications For Surgery:
Symptomatic primary hyperparathyroidism requiring surgical intervention
Asymptomatic primary hyperparathyroidism with specific criteria: serum calcium > 1 mg/dL above the upper limit of normal, 24-hour urinary calcium excretion > 400 mg, creatinine clearance < 60 mL/min, bone mineral density T-score <-2.5, or age < 50 years.
Indications For Sestamibi Guidance:
Preoperative localization of a single, presumed adenoma on sestamibi scintigraphy
Positive sestamibi scan correlating with biochemical evidence of hyperparathyroidism
Patients suitable for minimally invasive parathyroidectomy.
Contraindications To Sestamibi Guidance:
Multiglandular disease suspected on imaging or biochemistry
Prior neck surgery or radiation therapy that might obscure localization
Inability to undergo radionuclide imaging
Patients requiring extensive neck dissection.
Preoperative Preparation
Biochemical Assessment:
Serum calcium, albumin, intact parathyroid hormone (iPTH), vitamin D levels
Renal function tests
24-hour urine calcium and creatinine
Baseline electrolyte panel.
Imaging Studies:
Technetium-99m sestamibi scintigraphy (dual-phase imaging, SPECT/CT often used)
Ultrasound of the neck to assess gland size, location, and vascularity, and to complement sestamibi findings
CT or MRI may be used in select complex cases.
Patient Counseling:
Explanation of the procedure, including the use of radioactive tracer and potential risks and benefits
Discussion of expected recovery and follow-up
Informed consent process.
Medication Management:
Discontinuation of medications that can affect calcium levels (e.g., thiazide diuretics, lithium) as clinically appropriate
Ensuring adequate hydration.
Procedure Steps
Imaging Correlation:
Careful review of sestamibi scan and ultrasound findings to identify the presumed location of the hyperfunctioning gland
Correlating imaging with palpation of the neck during surgery.
Surgical Approach:
Typically a limited cervical incision (2-4 cm), often in a skin crease, tailored to the localized lesion
Dissection is focused on the side of the suspected adenoma.
Intraoperative Localization:
Use of a gamma probe to detect areas of increased sestamibi uptake corresponding to the hyperfunctioning parathyroid tissue
Careful dissection in the vicinity of the detected uptake.
Excision And Confirmation:
Targeted excision of the identified abnormal parathyroid gland
Intraoperative PTH (ioPTH) monitoring is crucial to confirm successful removal of all hyperfunctioning tissue
Confirmation of gland viability and absence of gross malignancy.
Closure:
Hemostasis achieved
Minimal drain placement if any
Layered closure of the incision.
Postoperative Care
Monitoring:
Close monitoring of serum calcium and iPTH levels within hours postoperatively
Assessment for signs and symptoms of hypocalcemia (e.g., tetany, paresthesias).
Management Of Hypocalcemia:
Intravenous calcium administration for symptomatic hypocalcemia
Oral calcium and vitamin D supplementation for persistent or mild hypocalcemia
Gradual weaning of supplementation as serum calcium normalizes.
Pain Management:
Standard analgesia as required
Patients typically experience minimal postoperative pain.
Discharge Criteria:
Stable serum calcium levels, absence of significant hypocalcemia symptoms, ability to tolerate oral intake, and minimal incisional pain
Typically discharged within 24-48 hours.
Complications
Early Complications:
Transient or persistent hypocalcemia
Recurrent laryngeal nerve injury (hoarseness, vocal cord dysfunction)
Hematoma formation
Wound infection
Seroma formation.
Late Complications:
Persistent or recurrent hyperparathyroidism due to missed hyperfunctioning glands or hyperplasia
Ectopic parathyroid tissue
Neck scarring.
Prevention Strategies:
Accurate preoperative localization
Meticulous surgical technique with attention to anatomical landmarks and recurrent laryngeal nerve identification
Use of intraoperative PTH monitoring
Careful assessment for multiglandular disease.
Key Points
Exam Focus:
Understanding the role of sestamibi in localization for focused parathyroidectomy
Differentiating between adenoma, hyperplasia, and ectopia
Interpretation of ioPTH levels
Indications and contraindications for minimally invasive parathyroidectomy.
Clinical Pearls:
Always correlate sestamibi findings with ultrasound
A negative sestamibi scan does not exclude a parathyroid adenoma, especially if highly ectopic
Consider SPECT/CT for challenging localizations
Meticulous hemostasis is key in minimally invasive surgery.
Common Mistakes:
Over-reliance on imaging without biochemical correlation
Inadequate assessment for multiglandular disease
Failure to use ioPTH monitoring
Incomplete knowledge of operative anatomy and nerve pathways
Misinterpreting sestamibi uptake in thyroid tissue.