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

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.

A Nested Case-Control Study on the Risk of Surgical Site Infection After Thyroid Surgery.

INTRODUCTION: It is unclear if antibiotic prophylaxis reduces the risk of surgical site infection (SSI) in thyroid surgery. This study assessed risk factors for SSI and antibiotic prophylaxis in subgroups of patients. METHOD AND DESIGN: A nested case-control study on patients registered in the Swedish National Register for Endocrine Surgery was performed. Patients with SSI were matched 1:1 by age and gender to controls. Additional information on patients with SSI and controls was queried from attending surgeons using a questionnaire. Risk factors for SSI were evaluated by logistic regression analysis and presented as odds ratio (OR) with 95% confidence interval (CI). RESULTS: There were 9494 operations; 109 (1.2%) patients had SSI. Patients with SSI were older (median 53 vs. 49 years) than patients without SSI p = 0.01 and more often had a cancer diagnosis 23 (21.1%) versus 1137 (12.1%) p = 0.01. In the analysis of patients with SSI versus controls, patients with SSI more often had post-operative drainage 68 (62.4%) versus 46 (42.2%) p = 0.01 and lymph node surgery 40 (36.7%) versus 14 (13.0%) p < 0.01, and both were independent risk factors for SSI, drain OR 1.82 (CI 1.04-3.18) and lymph node dissection, OR 3.22 (95% CI 1.32-7.82). A higher number of 26(62%) patients with independent risk factors for SSI and diagnosed with SSI did not receive antibiotic prophylaxis. Data were missing for 8 (31%) patients. CONCLUSION: Lymph node dissection and drain are independent risk factors for SSI after thyroidectomy. Antibiotic prophylaxis might be considered in patients with these risk factors.

Influence of surgical and postoperative treatment on survival in differentiated thyroid cancer.

BACKGROUND: The extent of thyroidectomy in patients with differentiated thyroid cancer (DTC) remains controversial. The aim of this study was to identify how surgical technique and postoperative treatments influence survival and locoregional recurrence in DTC. METHODS: A nested case-control study was conducted in a cohort of 5123 patients diagnosed with DTC in Sweden between 1958 and 1987. One matched control subject was selected randomly for each patient who died from DTC. Details regarding surgery and postoperative treatments were obtained from medical records. The effect of treatment on survival was estimated by conditional logistic regression. RESULTS: Patients not treated surgically had a poorer prognosis, but the risk of death from DTC was not affected by the choice of surgical technique. The extent of surgery influenced survival only in patients with TNM stage III disease. Locoregional recurrence resulted in a fivefold increased risk of death. Postoperative treatment was not associated with improved survival. CONCLUSION: In operated patients, the most important prognostic factor was complete removal of the tumour. The extent of removal of remaining thyroid tissue was of prognostic importance in stage III disease only. Adjuvant postoperative treatment did not influence the prognosis favourably.