Methods
This retrospective multicenter study analyzes pediatric patients,
operated over a 11 year period (January 2009 - December 2019) at several
institutions (Division of Paediatric Surgery and Division of Endocrine
Surgery at University of Pisa, Division of Pediatric Surgery at “Regina
Margherita Hospital” in Turin, General Pediatric and Thoracic Surgery
at Bambino Gesù Children׳s Hospital-Research Institute in Rome,
Pediatric Surgery at Department of Woman and Child Health in Padua and
the National Cancer Institute in Milan).
The variables taken into consideration are: gender, age, tumor size,
type of surgery performed (total thyroidectomy - TT or hemithyroidectomy
- HT), autotransplantation into the ipsilateral sternocleidomastoid
muscle in case of incidental parathyroidectomy, lymph node dissection,
histology (papillary carcinoma, diffuse sclerosing variant, follicular
carcinoma, medullary carcinoma within genetic forms, such as MEN2A,
MEN2B and FMTC). The age range at the operation was 4 - 18, with a mean
age of 13.6 years. The exclusion criteria were: primitive
hypoparathyroidism, low levels of vitamin D, low calcium level measured
preoperatively, previous parathyroidectomy due to hyperparathyroidism or
patients who received supplementary calcium treatment due to other
causes. Follow-up after surgery consisted of measuring serum calcium
levels by blood sampling. Post-operative hypocalcemia was defined as a
serum calcium level of less than 8 mg/dl. The first measurement was made
within 24 hours after the operation. A serum level check was repeated
once a day in the three days following discharge. Postoperative
parathyroid hormone (PTH) levels were determined in case of persistent
low serum calcium levels 33-34. In patients with serum
calcium levels <8 mg/dl with or without associated symptoms,
intravenous or oral calcium was administered. In case of persistent
hypocalcemia, subsequent serum calcium samples were drawn, with a
frequency ranging from one per week to one per month4.
Calcium supplementation doses were adjusted during follow-up according
to symptoms and serum calcium levels 35. TtHP was
considered when patients received calcium supplementation and/or had a
normalization in PTH levels within 6 months after surgical treatment.
PtHP was defined as the need for calcium supplementation with or without
active Vitamin D even 6 months after surgery 7.