A systematic review and meta-analysis of Harmonic Focus in thyroidectomy compared to conventional techniques

INTRODUCTION: Several meta-analyses have been performed comparing the use of a variety of ultrasonic devices in thyroidectomy to conventional procedures. These studies have shown the superiority of ultrasonic devices for most outcomes studied including faster operative time and less blood loss, and equivalent or better safety for recurrent laryngeal nerve paresis and hypocalcemia. The current work is the first to examine a single ultrasonic device specifically designed for thyroid surgery, the Harmonic Focus, in order to confirm its efficacy and safety in thyroidectomy. METHODS: A comprehensive literature search without language restrictions was performed for randomized clinical trials comparing Harmonic Focus and conventional clamp, cut and tie in thyroidectomy. Outcome measures included operating time, blood loss, post-operative pain, length of hospital stay, hypocalcemia and recurrent laryngeal nerve paresis. Risk of bias was analyzed for all studies. Meta-analysis was performed using random effects models with the inverse-variance method for mean differences of continuous variables and the Mantel-Haenszel method for risk ratios of dichotomous variables. RESULTS: A total of 14 studies met the inclusion criteria. Harmonic Focus reduced operative time by 29 min, a 31 % decrease (p < 0.001), intra-operative blood loss by 45 ml (p < 0.001), post-operative pain (p < 0.001), length of hospital stay by 0.68 days (p = 0.005), drainage volume by 29 ml (p = 0.01), and occurrence of transient hypocalcemia by 40 % (p = 0.001). There were no significant differences between Harmonic Focus and conventional procedures in rate of persistent hypocalcemia, or rates of transient and persistent recurrent laryngeal nerve paresis. CONCLUSION: This is the first meta-analysis of Harmonic Focus in thyroid surgery. In agreement with meta-analyses previously performed on ultrasonic devices, use of the Harmonic Focus has been shown to be a more effective surgical procedure compared to conventional methods in thyroidectomy. The low occurrence of hypocalcemia and recurrent laryngeal nerve paresis confirms that Harmonic Focus can improve thyroidectomy efficiency without increasing the risk of complications.