title: A systematic review and meta-analysis of Harmonic Focus in thyroidectomy compared to conventional techniques.
abstract: BACKGROUND
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Ethicon Inc, 4545 Creek Rd, Cincinnati, OH 45242 USA.
authors.forename: Hang
authors.initials: H
authors.lastname: Cheng
authors.affiliation: Cornerstone Research Group, 204-3228 South Service Road, Burlington, ON L7N 3H8 Canada.
authors.forename: Ireena
authors.initials: I
authors.lastname: Soleas
authors.affiliation: Cornerstone Research Group, 204-3228 South Service Road, Burlington, ON L7N 3H8 Canada.
authors.forename: Nicole C
authors.initials: NC
authors.lastname: Ferko
authors.affiliation: Ethicon Inc, 4545 Creek Rd, Cincinnati, OH 45242 USA.
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Clymer
authors.affiliation: Ethicon Inc, 4545 Creek Rd, Cincinnati, OH 45242 USA.
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Amaral
keywords: Harmonic Focus; Meta-analysis; Thyroidectomy; Ultrasonic