Increased neck circumference- an indicator of post thyroidectomy haemorrhage: JAMA

Germany: Neck circumference measurement is a simple and accurate diagnostic tool to detect post thyroidectomy haemorrhage in routine clinical care, states a diagnostic accuracy study results published in The JAMA Otolaryngology Head Neck Surgery.

Post thyroidectomy haemorrhage is a rare but potentially life-threatening complication of thyroid surgery which may cause airway compression and require emergency surgical treatment. There is no reliable non-invasive method for its early detection. It may increase pressure as well as volume in the cervical compartment, and consequently, increase neck circumference. Some case reports mention neck circumference measurement as a suitable method for detecting subsequent bleeding.

Researchers conducted a study of diagnostic accuracy including 2 cohorts of patients who underwent thyroidectomy (60 prospective, 353 retrospectives) to evaluate the diagnostic accuracy of neck circumference measurement for early detection of postoperative haemorrhage after thyroidectomy. Repeated perioperative neck circumference were measurements to evaluate the association of increased neck circumference with post thyroidectomy haemorrhage among patients at risk for haemorrhage. Additionally, data on demographic information and risk factors for post thyroidectomy haemorrhage were examined.

Key findings of the study,

• There was a relevant difference in neck circumference between patients with and without haemorrhage after thyroidectomy

• In group 1, postoperative neck circumference increased by a median (range) of 5.0 cm in patients with haemorrhages, and only 1.0 cm in patients with no postoperative bleeding.

• A cutoff value of 7% or greater increase in neck circumference showed high sensitivity and specificity values in the prospective evaluation and retrospective validation for detection of haemorrhage after thyroidectomy.

• Group-2 showed a difference in median (range) increase of postoperative neck circumference between patients with haemorrhage and those without—3.0 cm vs 0.0 cm.

• Considering 12 false-positive and 332 correct-negative results, the diagnostic tool showed a sensitivity of 0.89 and a specificity of 0.97.

Researchers conclude that increased neck circumference may indicate post thyroidectomy haemorrhage but the clinical signs should also be considered because not every patient with increased neck circumference is symptomatic nor develop increased neck circumference. Based on the results of the ROC curve analysis, excellent levels of specificity and sensitivity are attained with the cutoff of a 7% or greater increase in neck circumference and it accurately distinguished between patients with and without a post thyroidectomy haemorrhage.

The authors propose close clinical observation along with repeated neck circumference measurements during the first 8 to 12 hours postoperatively. If a patient's neck circumference measurement increases by 7% or more or if clinical symptoms (respiratory distress, voice changes, difficulty swallowing) occur with or without an increase in neck circumference, the surgeon should consider timely revision surgery.

von Ahnen T, Schardey J, von Ahnen M, et al. Neck Circumference Measurement for Surveillance and Early Detection of Hemorrhage After Thyroidectomy: A Diagnostic Accuracy Study. JAMA Otolaryngol Head Neck Surg. Published online June 09, 2022. doi:10.1001/jamaoto.2022.1180