Accuracy of Sestamibi Scan in parathyroid surgery

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Accuracy of Sestamibi Scan in parathyroid surgery

• 1. Denham D and Norman J.
• J Am Coll Surg 186 (3) 293-305 1998.
• 2. Delbridge LW et al
• MJA 172(9) 418-422 May 2000.
• 3. Reeve TS, Delbridge LW, Madden GJ.
• Aust NZ J Surg 70(4) 244-250 April 2000.

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Sestamibi Scan

• What is Sestamibi?
• Hexakis-2-methoxyisobutyl isonitrite
• Biokinetic imaging basis of Sestamibi
• Increased metabolic activity ? nonspecific
  localization in mitochondria cytoplasm
• Dual phase VS Subtraction scan

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Sestamibi Scan

• Metaanalysis
• 6331 patients over 10 years
• 87 single adenoma
• Sensitivity 90 (80-100)
• Specificity 99 (93-100)

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Primary Hyperparathyroidism

• Aetiology
• Single adenoma 87
• Double adenomas 3
• Hyperplasia 9
• Carcinoma 1

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Reliability of Sestamibi Scan

• Sensitivity 90
• Single adenoma 87
• Suitable for 90 X 87 78
• Full exploration 22
• Specificity 99
• Failure rate 1

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What does it imply?

• Selection of patients for minimally invasive
  parathyroidectomy
• Advantages
• Cosmetic result
• Possible local anaesthesia
• Less pain/discomfort
• More cost-effective

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Cost-effectiveness

• Minimally invasive vs full exploration
• L/A vs G/A
• Operating time
• Frozen section
• LOS
• ?Less morbidity
• Full exploration 22 ? waste of preop scan
• Thus, needs 78 to offset 22

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Summary I

• Preoperative Sestamibi scan
• sensitivity 90
• specificity 99
• suitable for 78 of 1o hyperparathyroidism
• success rate 99 for single adenoma
• Minimally invasive parathyroidectomy
• cost-effective
• less morbidity

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LW Delbridge MJA

• Prospective, non-randomized, non-blinded trial
• Period 05/98 to 10/99
• Patients 50 MIP 150 full exploration

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Results I

• MIP
• 42(84) successfully completed cured
• 7 (14) converted to open cured
• 1 (2) persistent hyperparathyroidism
• Overall cure rate 98
• Complications
• 3 had temporary RLN palsy
• No wound haematoma
• No wound infection

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Results II

• Full exploration
• 147 (98) successful
• 3 (2) persistent hyperparathyroidism
• Complications
• 1 had temporary RLN palsy
• 4 wound haematoma
• No wound infection

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Summary II

• Full exploration
• 98 success rate
• Acceptable scar
• minimal complication of lt1
• MIP
• Preop Sestamibi scan accurate BUT if used alone,
  missed at least 1 enlarged gland in gt10 of cases
  (Pattou et al Surgery 1999 ---- double adenomas
  or incorrect localisation)
• Intraoperative gamma probe or QPTH

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Reeve, Delbridge, Madden

• Systematic R/V of literature
• Preop localisations
• sestamibi, Th-Tc, U/S, CT
• Results
• Overall complications favour MIP
• Operating times, LOS favour MIP
• Deficiencies of studies
• selection bias
• large CI

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Summary III

• Safety
• No clear benefit, possible rupture, S/C
  emphysema, difficult visualization
• Efficacy
• Original approach already cost-effective
• New technique needs to be better
• Recommendations
• Strict selection criteria
• Level 2.2 procedure
• Needs further studies

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Conclusion

• Sestamibi scan is accurate
• Strict selection of patients for MIP important
  based on preop Sestamibi
• Preop Sestamibi intraoperative nuclear mapping
  or QPTH improves success rate
• Currently MIP not proven to be better
• Needs established technique
• Needs further trials