title: Visualizing fewer parathyroid glands may be associated with lower hypoparathyroidism following total thyroidectomy.
abstract: BACKGROUND
  It remains uncertain whether the number of parathyroid glands (PGs) seen during extra-capsular dissection impacts short- and long-term hypoparathyroidism. Our study aimed to address this by analyzing patients who underwent total thyroidectomy for benign disease.
  
  
  METHODS
  Consecutive patients undergoing total thyroidectomy were analyzed. The extra-capsular dissection technique was performed throughout the study period. The number of PGs identified, auto-transplanted and found on excised specimen was recorded prospectively. The number of PGs in situ was equaled to four minus the number of PGs auto-transplanted and PGs found on specimen. Temporary hypoparathyroidism was defined as serum adjusted calcium <2.00 mol/L 24 h after surgery and/or need for oral supplements while protracted hypoparathyroidism meant subnormal PTH (<1.2 pmol/L) at 4-6 weeks and/or need for >6-week oral supplements. Permanent hypoparathyroidism was defined as need for oral supplements for ≥1 year.
  
  
  RESULTS
  Five-hundred and sixty-nine patients were eligible for analysis. After adjusting for other significant parameters, greater number of PGs identified was an independent risk factor for temporary (p < 0.001) and protracted hypoparathyroidism (p = 0.007). Mean recovery time from protracted hypoparathyroidism for identifying ≤three PGs was significantly shorter than identifying all four PGs (2.8 vs. 7.8 months, p < 0.001). Chance of having all four PGs in situ decreased with greater number of PGs identified (p < 0.001).
  
  
  CONCLUSIONS
  When the extra-capsular technique was adopted during total thyroidectomy, identifying fewer PGs in their orthotopic positions not only lowered risk of temporary and protracted hypoparathyroidism but also shortened recovery from protracted hypoparathyroidism.
authors.affiliation: Division of Endocrine Surgery, Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China. blang@hkucc.hku.hk.|Division of Endocrine Surgery, Department of Surgery, Queen Mary Hospital, 102 Pokfulam Road, Hong Kong, SAR, China. blang@hkucc.hku.hk.
authors.forename: Brian Hung-Hin
authors.initials: BH
authors.lastname: Lang
authors.affiliation: Division of Endocrine Surgery, Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China.
authors.forename: Diane T Y
authors.initials: DT
authors.lastname: Chan
authors.affiliation: Division of Endocrine Surgery, Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China.
authors.forename: Felix Che-Lok
authors.initials: FC
authors.lastname: Chow
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D004210:Dissection; D005260:Female; D006801:Humans; D007011:Hypoparathyroidism / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010280:Parathyroid Glands / Q000473:pathology* / Q000601:surgery; D011183:Postoperative Complications / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D013959:Thyroid Diseases / Q000150:complications / Q000473:pathology* / Q000601:surgery*; D013965:Thyroidectomy / Q000009:adverse effects*; D014182:Transplantation, Autologous
keywords: Hypoparathyroidism; Parathyroid hormone; Risk factors; Total thyroidectomy