The use of near-infrared autofluorescence during total laryngectomy with hemi- or total thyroidectomy

Abstract

Purpose: The aim of this study is to describe the use of near-infrared autofluorescence (NIR-AF) to identify and preserve parathyroid glands (PGs) in a group of patients with advanced hypopharyngeal/laryngeal cancer undergone total (pharyngo)laryngectomy with hemi- or total thyroidectomy.

Methods: At San Raffaele Hospital, Milan (Italy), from January 2021 to May 2021, 7 patients affected by cT4a laryngeal squamous cell carcinoma (SCC) underwent surgery using an autofluorescence detection system (Fluobeam-Fluoptics^®). For proper surgical planning, the demolition phase envisaged extension of the intervention to 4 hemithyroidectomies and 3 total thyroidectomies associated, respectively, with homolateral or bilateral CCND. Serum calcium, ionized calcium, and parathyroid hormone (PTH) levels at post-operative day (POD) 1 and 2 and at 2 weeks after surgery were monitored. Finally, we compared the data obtained with a cohort of patients who underwent surgery without the adoption of NIR-AF.

Results: With the use of NIR-AF, 18/20 PGs were identified, of which 7/18 were preserved exclusively thanks to the use of autoflorescence. The technique also made it possible to identify and isolate three PGs from the surgical specimen, which were subsequently transplanted only after intraoperative histological confirmation. On POD-1, 3/7 patients (42.8%) were hypocalcemic; on POD-2 and after 2 weeks only 1/7 patient (14.2%) was hypocalcemic. Comparing the two groups, we highlighted that the utilization of NIR-AF was related to a significant decrease of median serum (p = 0.026) and ionized calcium levels (p = 0.017) 2 weeks after surgery. Using this new technology, in no case did definitive histological examination reveal the presence of PGs in the surgical specimen, reaching an accuracy of 100%.

Conclusions: In our cohort of patients who underwent total (pharyngo)laryngectomy with hemi- or total thyroidectomy, the use of near-infrared autofluorescence improved medium term postoperative hypocalcemia rates. This new technology helps to achieve a better calcemic outcome compared to the standard naked eye approach, since it helps the surgeon to identify and preserve parathyroid glandular tissue with a lower incidence of post-operative hypocalcemia.

Keywords: Hypocalcemia; Hypoparathyroidism; Laryngeal cancer; Laryngectomy; Near-infrared autofluorescence; Parathyroid glands; Thyroidectomy.