Minimally Invasive Parathyroidectomy for Primary Hyperparathyroidism Joint Hospital Surgical Grand Round 18 April 2009 Dr. David KW Leung United Christian Hospital
Outline Primary hyperparathyroidism Surgical treatment Bilateral neck exploration Minimally invasive parathyroidectomy (MIP) Conclusion
Definition Primary hyperparathyroidism - A sporadic or familial disorder associated with hyperCa, elevated or inappropriately raised PTH levels and parathyroid gland enlargement Bailey & Love’s Short Practice of Surgery
Parathyroidectomy Conventional bilateral cervical exploration Minimally invasive/ Limited parathyroidectomy
Bilateral neck exploration ‘Gold standard’ Pre-op localization of abnormal parathyroid gland not mandatory The success is based on a thorough knowledge of the anatomy and embryological evolution of the glands Success rate – 95-98%
Bilateral neck exploration To identify all 4 parathyroid glands Only enlarged glands are removed whether single- or multiple- gland disease found If 4 glands are enlarged, subtotal parathyroidectomy is performed; leaving a single vascularized gland remnant no larger than a normal parathyroid
Limited/minimal invasive parathyroidectomy The need for routine bilateral neck exploration being challenged because: Pathology of the disease Improvement of pre-op localization studies Introduction of quick parathyroid hormone assay (QPTH) Confirm removal of all hyper-functioning parathyroid tissue
Pathology Adenoma 85% Hyperplasia14% Carcinoma<1%
Imaging and pre-op localization Ultrasound technetium-99M sestamibi scan (MIBI) CT scan MRI parathyroid angiography/ selective venous sampling
Ultrasound Sensitivity 70-80% Lower sensitivity in re-operative cases False-positive (15-20%) due to muscle, vessels, thyroid nodules, LN and oesophageal pathology has difficulty locating abnormalities in the retro-oesophageal, retrosternal, retrotracheal and deep cervical areas
Technetium-99M sestamibi scan (MIBI) technetium-99M sestamibi concentrated in abnormal parathyroid glands
Technetium-99M sestamibi scan (MIBI) Sensitivity % drawbacks Not always identify patients with multiple adenomas or four-gland hyperplasia Failed to localized small adenomas
Limited/minimal invasive parathyroidectomy General/ local anaesthesia Accurate pre-op localization is a prerequisite Targeted on one specific parathyroid gland Procedure carried out through a small incision Parathyroid gland Thyroid
Limited/minimal invasive parathyroidectomy Exclusion Suspected multiple - gland disease on imaging studies History of familial hyperparathyroidism or multiple endocrine neoplasia
Evidence-based?
1. Miccoli et al. Video-assisted vs. conventional parathyroidectomy in primary hyperparathyroidism: a prospective randomized study. Surgery 1999;126: Bergenfelz A. et al. Unilateral vs. bilateral neck exploration for primary hyperparathyroidism: a prospective randomized controlled trial. Ann Surg. 2002;236: Westerdahl et al. Unilateral vs. bilateral neck exploration for primary hyperparathyroidism: Five-year Follow-up of a randomized controlled trial. Ann Surg. 2007;246: Bergenfelz A et al. Conventional bilateral cervical exploration vs. open minimally invasive parathyroidectomy under local anaesthesia for primary hyperparathyroidism. Br. J Surg. 2005;92: Russell CF et al. Randomized clinical trial comparing scan-directed unilateral vs. bilateral cervical exploration for primary hyperparathyroidism due to solitary adenoma. Br. J Surg. 2006;93:
Patients with sporadic primary hyperparathyroidism Minimally invasive parathyroidectomy - Unilateral - focused - video-assisted Bilateral cervical exploration Compare - Cure rate - early post-op hypoCa/ Ca level - Operative time - cost - pain - Cosmetic results - Complication/ vocal cord palsy Study design - overall
Study design - 1 Patients with sporadic primary hyperparathyroidism Minimally invasive parathyroidectomy Bilateral cervical exploration Sestamibi scan/ USG +ve Randomization - ve Excluded 1. Miccoli et al. Surgery Bergenfelz et al. Br. J. Surg Russell et al. Br. J. Surg Expose all 4 glands Gross morphology Frozen section Drop in ioPTH
Study design - 2 Patients with sporadic primary hyperparathyroidism Minimally invasive parathyroidectomy Bilateral cervical exploration Sestamibi scan +ve Randomization - ve Explore +ve side Explore left side first If no enlarged gland on first explored side Stop if one enlarged gland found + drop in ioPTH 2. Bergenfelz et al. Ann. Surg Westerdahl et al. Ann. Surg. 2007
Study design - summary Miccoli et al.Bergenfelz et al. Westerdahl et al. Bergenfelz et al.Russell et al. Surgery 1999 Annals of Surg Annals of Surg Br. J Surgery 2005 Br. J Surg Type of studyRCT No. of patient (MIP + BCE = Total) = = = = = 100 mode of explorationVAP vs. BCEunilateral vs. bilateral targeted (MIP) vs. bilateral unilateral vs. bilateral Anaesthesia GA except 2 in VAP group GA LA in MIP/ GA in BCE GA Pre-op localization modality USGsestamibi Use of ioPTH in MIP gp.Yes No
Results - 1 Miccoli et al.Bergenfelz et al. Westerdahl et al. Bergenfelz et al.Russell et al. Surgery 1999 Annals of Surg Annals of Surg Br. J Surgery 2005 Br. J Surg Cure rateAll (up to 6 months)Same up to 5 year Same up to 6 months All (mean FU 23 months) Early post-op hypoCa Higher in BCE (NS) Higher in BCE (p < 0.05) / Higher in BCE (p = NA) Nil Post-op Ca level / lower in BCE on D2 (2.15 vs. 2.26; p < 0.01) Same at 1and 5 years slightly lower in BCE on Day 3 (0.022) / OT time (MIP vs. BCE) shorter (57 vs. 70 mins; p < 0.05) shorter (72 vs. 82 min.; p = 0.22) shorter (41 vs. 63mins; p = 0.024) shorter (65.6 vs mins; p = 0.007) NA = Not available in the paper NS = not significant
Results - 2 Miccoli et al.Bergenfelz et al.Westerdahl et al.Bergenfelz et al.Russell et al. Surgery 1999 Annals of Surg Annals of Surg Br. J Surgery 2005 Br. J Surg CostSimilar slightly higher in MIP (US$2258 vs. 2097; p = 0.13) // Pain less in VAP (p < 0.05) /Similar/ ComplicationSimilar (p = NA) higher in BCE (laryngeal edema, bleeding; p = 0.27) Higher in BCE (wound seroma; p = NA) Nil Vocal cord palsy 1 patient in VAP (p not calculated) higher in unilateral gp. (temporary; 2 vs. 1; p = 0.99) 1 patient in MIP (temporary); p = NA) 2 patients in BCE (permanent;p = NA) Cosmetic results Superior in VAP (p = NA) /Same/ NA = Not available in the paper NS = not significant
Conclusion MIP is as effective as conventional bilateral neck exploration for primary hyperparathyroidism Advantage Less early post-operative hypoCa Can be done under LA Shorter operative time
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