Overview
Definition:
Primary hyperparathyroidism (PHPT) is a condition characterized by excessive secretion of parathyroid hormone (PTH) by one or more parathyroid glands, leading to hypercalcemia
Reoperative strategy in PHPT refers to the surgical approach for patients who have undergone prior parathyroid surgery but still have or have developed persistent or recurrent hypercalcemia.
Epidemiology:
While initial parathyroidectomy is successful in over 95% of cases, persistent hyperparathyroidism occurs in 1-5% and recurrent hyperparathyroidism in up to 1% of patients
Factors contributing to reoperation include missed adenomas, multiglandular disease, ectopic parathyroid glands, or technical surgical errors
It is more common in younger patients and those with multiglandular disease.
Clinical Significance:
Reoperative parathyroid surgery is technically more challenging than initial surgery due to altered anatomy, fibrosis, and scar tissue
Successful reoperation is crucial to prevent long-term complications of hypercalcemia, including osteoporosis, nephrolithiasis, cardiovascular disease, and neurological symptoms
A well-defined reoperative strategy is vital for improving patient outcomes and avoiding further morbidity.
Indications For Reoperation
Persistent Hypercalcemia:
Symptomatic or asymptomatic hypercalcemia (serum calcium > 1 mg/dL above the upper limit of normal) persisting beyond 6 months after initial parathyroidectomy without other identifiable causes.
Recurrent Hypercalcemia:
Development of hypercalcemia after a documented period of normocalcemia following initial parathyroidectomy.
Diagnostic Confirmation:
Exclusion of other causes of hypercalcemia (e.g., malignancy, sarcoidosis, familial hypocalciuric hypercalcemia) is mandatory before proceeding to reoperation.
Symptomatic Burden:
Significant symptoms attributable to hypercalcemia, such as bone pain, kidney stones, psychiatric disturbances, or fatigue, necessitating intervention.
Diagnostic Approach Reoperation
History And Physical Examination:
Detailed history of prior surgeries, including operative reports and pathology findings
Thorough examination focusing on neck scars, palpable masses, and signs of hypercalcemia (e.g., bone tenderness, renal colic history)
Assess for symptoms of MEN syndromes.
Biochemical Evaluation:
Repeat serum calcium, PTH (intact), phosphate, alkaline phosphatase, and renal function tests
Measurement of 24-hour urinary calcium excretion to differentiate from familial hypocalciuric hypercalcemia
Consider vitamin D levels.
Imaging Modalities:
Preoperative imaging is critical for localization
Options include high-resolution ultrasound (US), sestamibi scanning (SPECT/CT), 4D-CT scan, and MRI
US is often the first-line imaging
Sestamibi is useful for identifying ectopic or deeper glands
4D-CT provides excellent anatomical detail, especially for complex cases.
Localization Of Ectopic Glands:
Ectopic glands can be located in the mediastinum, thoracic inlet, or within the thymus
Imaging should specifically look for these unusual locations
Persistent elevation of PTH despite normocalcemia might indicate a missed ectopic gland.
Surgical Strategy Reoperation
Preoperative Planning:
Thorough review of all previous surgical and imaging reports
Team discussion involving surgeons and endocrinologists
Patient counseling regarding the increased risks and complexities.
Operative Technique:
Often requires a formal cervical exploration, potentially extending to a sternotomy if mediastinal exploration is suspected
Careful dissection to identify remaining parathyroid tissue, preserving the recurrent laryngeal nerves and thyroid gland
Identifying and excising all abnormal tissue.
Identification Of Glands:
Systematic exploration of all four standard parathyroid gland locations, and the thymic remnant
Intraoperative PTH monitoring (IOPTH) is essential to confirm successful removal of hypersecreting tissue, aiming for a >50% drop from baseline 10-20 minutes after suspected adenoma removal.
Management Of Ectopic Glands:
If an ectopic gland is identified in the mediastinum, it may necessitate a sternotomy or thoracotomy
Meticulous identification and removal are key
Ultrasound-guided fine-needle aspiration of suspected ectopic glands with PTH assay can be helpful if accessible.
Minimally Invasive Approaches:
While less common in reoperative cases due to scar tissue and altered anatomy, if a single, well-localized adenoma is identified and the previous surgery was limited, a focused re-exploration might be considered under expert hands.
Management Of Persistent Hypoparathyroidism Post Reoperation
Monitoring Serum Calcium:
Close monitoring of serum calcium levels in the immediate postoperative period
Patients may develop transient or persistent hypocalcemia.
Calcium And Vitamin D Supplementation:
Intravenous calcium may be required initially for severe hypocalcemia
Oral calcium and active vitamin D metabolites (e.g., calcitriol) are then initiated and titrated to maintain normocalcemia.
Long Term Follow Up:
Regular monitoring of serum calcium, PTH, and renal function
Educate patients on symptoms of hypocalcemia (e.g., perioral numbness, paresthesias, tetany) and to report them promptly.
Complications Of Reoperative Parathyroidectomy
Injury To Recurrent Laryngeal Nerve:
Higher risk than in primary surgery due to scarring and altered anatomy
Can result in unilateral or bilateral vocal cord paralysis.
Hypoparathyroidism:
Transient or permanent hypoparathyroidism can occur if all parathyroid tissue is inadvertently removed or devascularized
This is a significant complication requiring lifelong treatment.
Bleeding And Hematoma:
Increased risk due to vascular changes and fibrosis in the operative field.
Scarring And Cosmetic Concerns:
Fibrous scar tissue can lead to prominent neck scarring and potential cosmetic issues.
Key Points
Exam Focus:
Reoperative parathyroid surgery is technically demanding
meticulous preoperative localization and intraoperative PTH monitoring are crucial
Understanding the causes of persistent/recurrent hyperparathyroidism is key.
Clinical Pearls:
Always consider ectopic glands in reoperative cases
IOPTH is your best friend to confirm the extent of resection
Be prepared for sternotomy if mediastinal exploration is needed
Postoperative hypocalcemia is common
vigilant monitoring and supplementation are essential.
Common Mistakes:
Inadequate preoperative localization leading to prolonged, blind neck dissection
Failure to consider multiglandular disease in the initial workup
Misinterpretation of IOPTH
Not adequately preparing for potential sternotomy
Underestimating the risk of recurrent laryngeal nerve injury.