Association between perioperative hypertension and haematoma formation in neck dissection for head and neck cancer

Background: Neck dissection is a well-established technique for the oncological removal of involved or high-risk regional neck lymph nodes. Haematoma is a recognised complication that affects approximately 5% of patients following neck dissection. It is common for patients to develop hypertension following surgery. The aim of our study is to investigate whether those patients who experienced post-operative hypertension had a greater risk of haematoma formation. Methods: This study was a retrospective cohort study of all patients undergoing neck dissection at Chris O'Brien Lifehouse, Sydney, Australia from August 2021 to April 2022. This study was approved by the Sydney Local Health District Human Research Ethics Committee (2019/ETH07164). Our primary outcome was haematoma formation in those with post-operative hypertension [defined as a systolic blood pressure (SBP) of greater than 180 mmHg at any time, the American Heart Association (AHA) definition of a hypertensive crisis] compared to those without. Our secondary outcome was the risk of haematoma formation in those with pre-existing hypertension. Risk ratios and Fisher's exact test were used to calculate significance. Results: One hundred and twenty-seven patients underwent neck dissection at our institution in the study period. The average age was 64.9 years and 72.4% were male. A proportion of 51.2% of patients had pre-existing hypertension. Eight out of 127 (6.3%) patients had a haematoma requiring evacuation in theatre. The relative risk of haematoma formation in patients with post-operative hypertension was 0.92 which was non-significant [95% confidence interval (CI): 0.12 to 7.05, P=0.985]. The relative risk of haematoma formation was 6.67 (95% CI: 0.85 to 52.71, P=0.0397) in those with known pre-operative hypertension. However, due to the small sample size of our study and resulting wide confidence intervals, these results should be interpreted with caution. Conclusions: Our study did not find a significant difference in the incidence of haematoma formation between those patients with post-operative hypertension and those without. The rate of haematoma was similar to that published in the literature at 6.3%. Our study also demonstrates that pre-existing hypertension is a risk factor for haematoma formation, in concordance with most of the other studies published in this area.