This is a prospective, single-blinded, randomized controlled trial to evaluate whether PTeye™ can reduce post-operative hypoparathyroidism (PH). The study will enroll consecutive patients undergoing total thyroidectomy in a teritary endocrine surgery unit in Hong Kong, randomizing them into receiving conventional surgery versus PTeye™-assisted surgery. Subjects will be assigned to the two groups before surgery. Subjects will be under medical care as in usual practice.

Post-operative hypoparathyroidism (PH) is a debilitating complication following total thyroidectomy. It arises from inadvertent removal or devascularization of the parathyroid glands. From a previous study in Hong Kong and other population-wide series, permanent PH rates could be as high as 11%, and transient PH rates being 30-48%, posing substantial burden on healthcare systems.

Near-infrared autofluorescence (NIRAF) technology has emerged to assist the identification and preservation of parathyroid glands during surgery. This study investigates the probe-based NIRAF device, PTeye™, which emits laser and receives NIR real-time, thereby detecting parathyroid glands by a simple touch of a probe.

A standardized protocol is devised to use PTeye™ for parathyroid identification at the early stage of surgery, in order to avoid devascularization or inadvertent removal of the parathyroids.

This is a prospective, single-blinded, randomized controlled trial to evaluate whether PTeye™ can reduce PH. The study will enroll consecutive patients undergoing total thyroidectomy in a tertiary endocrine surgery unit in Hong Kong. Patients will be randomized to receive conventional surgery or PTeye™-assisted surgery.

Inclusion Criteria:

• Adult patients ≥18 years of age
• Undergoing total thyroidectomy, or completion total thyroidectomy
• Pre-operative serum adjusted calcium levels within normal ranges

Exclusion Criteria:

• Patients on pre-operative calcium or vitamin D supplements
• Patients with pre-operative vitamin D deficiency, defined as serum vitamin D<30nmol/L
• Patients with untreated primary or secondary hyperparathyroidism
• Patient with known non-surgical hypoparathyroidism diseases
• Patients with estimated glomerular filtration rate <30ml/1.73m2/min, on dialysis, or having a history of kidney transplant