Evaluating risk factors for re-exploration due to postoperative neck hematoma after thyroid surgery: a nested case-control study

Langenbecks Arch Surg. 2019 Nov;404(7):815-823. doi: 10.1007/s00423-019-01836-4. Epub 2019 Nov 18.


Purpose: Postoperative bleeding after thyroid surgery remains a potentially lethal complication. Outpatient thyroidectomy is an increasing trend in the high volume centers. There is a need to identify risk factors for postoperative bleeding in order to select proper patients for outpatient thyroidectomy. This study aimed to investigate this issue using a national population-based register.

Material and method: A nested case-control study on patients registered in the Swedish national register for endocrine surgery (SQRTPA) was performed. Patients with postoperative bleeding were matched 1:1 by age and gender to controls. Additional information on cases and controls was obtained from attending surgeons using a questionnaire. Risk factors for postoperative bleeding were evaluated with logistic regression and are presented as odds ratios (ORs) with 95% confidence intervals (CIs). The time of bleeding in relation to surgery was also investigated.

Results: There were 9494 operations, and 174 (1.8%) of them involved postoperative bleeding. In the whole cohort, patients with postoperative bleeding were older, 58 (46-69) vs. 49 (37-62) years, than patients without, p < 0.01. Male patients had a higher risk of bleeding, OR 2.18 (95% CI 1.58-2.99). In the case-control cohort, drain was an independent risk factor for bleeding, OR 1.64 (1.05-2.57). Two-thirds of patients bled within 6 h after surgery. The incidence of bleeding after 24 h was 10%.

Conclusion: High age, male gender, and drain are independent risk factors for bleeding after thyroid surgery. Even with careful patient selection, prolonged observation might be necessary in thyroid surgery.

Keywords: Postoperative bleeding; Postoperative neck hematoma, risk factors; Thyroid surgery.

MeSH terms

  • Adult
  • Age Factors
  • Aged
  • Aged, 80 and over
  • Ambulatory Surgical Procedures
  • Case-Control Studies
  • Female
  • Hematoma / etiology
  • Hematoma / surgery*
  • Humans
  • Male
  • Middle Aged
  • Neck / surgery*
  • Odds Ratio
  • Postoperative Complications / etiology
  • Postoperative Complications / surgery*
  • Registries
  • Reoperation / adverse effects*
  • Risk Factors
  • Sex Factors
  • Symptom Assessment
  • Thyroidectomy / adverse effects*