AAES GUIDELINES 6: MINIMALLY INVASIVE PARATHYROIDECTOMY/ BILATERAL EXPLORATION/OPERATIVE APPROACH
RECOMMENDATION: Defined as a focused dissection, MIP is ideally used in patients who appear clinically and by imaging to have a single parathyroid adenoma. It is not routinely recommended in patients with known or suspected high risk of MGD.
COMMENT: Minimally Invasive Parathyroidectomy (MIP) or focused image-guided parathyroidectomy should only be used where there is confident high quality localisation of a parathyroid adenoma to a single site. If MGD is suspected , MIP is not the appropriate operation. Patient selection by imaging, family history, and anatomic factors is essential to achieving good outcomes with MIP.
RECOMMENDATION: Ex vivo PTH aspiration or frozen section is suggested to confirm the identity of parathyroid tissue during MIP
COMMENT: This is a matter of experience, and is important for low volume centres. Most experienced Australian parathyroid surgeons would only use a frozen section where there is some doubt about the pathology seen at surgery.
RECOMMENDATION: During MIP the discovery of MGD, the inability to identify an abnormal gland, or the failure to achieve an appropriate IPM drop should prompt conversion to BE.
COMMENT: The recommendation about IPM is not relevant to Australian centres because IOPTH measurement is not routinely used. However the principle is the same in that, if the expected pathology of an appropriate sized parathyroid adenoma corresponding to a localized abnormality is not identified at surgery or if more than one abnormal gland is found, that should prompt conversion to an open operation or bilateral exploration (BE).
RECOMMENDATION: BE provides a time-tested standard of efficacy and safety in the definitive treatment of pHPT. BE is recommended as the preferred operative strategy in situations of discordant or nonlocalizing preoperative imaging, when there is a high suspicion of MGD, when IPM is not available or ending criteria are unmet, or at the discretion of the surgeon.
COMMENT: This recommendation re-states the above reasons for not performing MIP ad emphasizes that BE is still a very good operation, with a high success rate, that was standard of care for over 50 years.
RECOMMENDATION: Planned BE is the preferred operative strategy in situations of discordant or nonlocalizing preoperative imaging when there is suspicion of MGD, or at the discretion of the surgeon
COMMENT: This is the Australian approach where bilateral exploration is offered only where is there is doubt on imaging about the presence of a single adenoma. It is direct contrast to the practice at The Norman Clinic where all patients undergo routine bilateral four gland parathyroid exploration, a much more extensive and complicated operation than focused parathyroidectomy (MIP).
RECOMMENDATION: BE for pHPT is defined by a standard technique in which all parathyroid glands are identified with exploration of expected and, if necessary, ectopic cervical locations. Subtotal parathyroidectomy should be performed if all parathyroid glands are abnormal. If an abnormal parathyroid gland cannot be identified, resection of normal parathyroid glands is not recommended.
COMMENT: Standard approaches to multiple of missing abnormal glands
Recommendation: In lithium-induced pHPT, the surgical approach may be either BE or MIP with preoperative imaging and IPM monitoring.
COMMENT: Each case of Lithium induced hyperparathyroidism needs to be evaluated and managed based on localisation studies
RECOMMENDATION: In patients with MEN1-associated pHPT, subtotal parathyroidectomy with consideration of transcervical thymectomy is recommended as the index operation.
COMMENT: The thymus needs to be removed because of the high likelihood of additional ectopic parathyroid glands in the thymus, as well as potential thymic carcinoid tumours. The Australian approach of focused parathyroidectomy for young patients with MEN1 has been very successful and should be discussed as an alternative to routine subtotal parathyroiidectomy.
RECOMMENDATION: In MEN2A-associated pHPT, resection of only visibly enlarged glands is recommended, in conjunction with IPM.
COMMENT: A more conservative approach is taken with MEN2 syndromes