title: Normocalcemic hyperparathyroidism: preoperatively a disease, postoperatively cured?
abstract: BACKGROUND
  Up to 44% of primary hyperparathyroidism patients have elevated parathyroid hormone (ePTH) with normal calcium postparathyroidectomy (PTx). The question is whether the surgical approach affects the incidence of this phenomenon.
  
  
  METHODS
  Patients with hyperparathyroidism and presumed single-gland disease on preoperative imaging who underwent PTx between 1994 and 2008 were identified and contacted for long-term follow-up. PTx was either a focused approach (minimally invasive approach [MIP]) or a bilateral neck exploration (BNE).
  
  
  RESULTS
  In total, 171 patients had PTH measured postoperatively (95 MIP and 76 BNE); 30 of 171 (17%) had ePTH with normal calcium (MIP 21 [22%] and BNE 9 [12%], P = .08). This occurred within 2 years in 48% and 67% and after 2 years in 52% and 33%, MIP vs BNE, respectively. Four patients recurred, 2 MIP and 2 BNE.
  
  
  CONCLUSIONS
  There is a trend toward a higher incidence of ePTH in patients having undergone an MIP. The etiology of ePTH is multifactorial but may represent an early recurrence.
authors.affiliation: Department of Surgery, University of Calgary, North Tower, 1403 29th Street Northwest, Calgary, Alberta, Canada T2N 2T9.
authors.forename: Heather C
authors.initials: HC
authors.lastname: Stuart
authors.affiliation: Department of Surgery, University of Calgary, North Tower, 1403 29th Street Northwest, Calgary, Alberta, Canada T2N 2T9.
authors.forename: Adrian
authors.initials: A
authors.lastname: Harvey
authors.affiliation: Department of Surgery, University of Calgary, North Tower, 1403 29th Street Northwest, Calgary, Alberta, Canada T2N 2T9. Electronic address: janice.pasieka@alberthealthservices.ca.
authors.forename: Janice L
authors.initials: JL
authors.lastname: Pasieka
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002118:Calcium / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000097:blood / Q000453:epidemiology / Q000517:prevention & control / Q000601:surgery*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures; D010281:Parathyroid Hormone / Q000097:blood*; D016105:Parathyroidectomy / Q000379:methods*; D011184:Postoperative Period; D057234:Preoperative Period; D012189:Retrospective Studies; D055502:Secondary Prevention; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D010281:Parathyroid Hormone; D002118:Calcium
keywords: Minimally invasive; Normocalcemia; Parathyroidectomy; Postoperative hyperparathyroidism