Ultrasonically activated shears in thyroidectomies: a randomized trial

Abstract

Objective: To test whether the advantages of the ultrasonically activated shears (UAS) observed in thyroidectomies in a previous matched-pair study could be repeated in a randomized trial.

Summary background data: The UAS has been documented, mainly in nonrandomized studies, to be a safe and fast device in video-assisted and conventional surgery.

Methods: Thyroidectomies and lobectomies performed for benign or malignant thyroid disease between August 1997 and January 1999 were included in this series. Separate randomization, resulting in four sets of envelopes, was done for one consultant endocrine surgeon and for senior residents for both lobectomies and for total thyroidectomies. The operations performed with the UAS were compared with operations performed with the conventional method, using ligatures as the main hemostatic method. Main outcome measures were operating time, postoperative serum calcium level, palsy of the recurrent laryngeal nerve, and amount of intraoperative and postoperative bleeding. Possible bias that could have been caused by imbalance between treatment groups for surgeon experience was tested by two-way analysis of covariance.

Results: Thirty-six patients were randomized, 19 to the UAS and 17 to the conventional group. Mean operating time was 99.1 minutes in the UAS group and 134.9 minutes in the conventional group. The average savings in operating time with the UAS was thus 35.8 minutes. There was no difference in complications between the groups. The estimated savings in operating time would have been 1.66 times that observed in this study if the groups had been unbalanced with reference to surgeon experience.

Conclusion: The UAS is a usable device in total thyroidectomies and lobectomies.

Figures

Figure 1. Area of forbearance while performing right lobectomy with the ultrasonically activated shears (UAS). The superior thyroid vessels have been cut using the shears. A safety margin of at least 5 mm was required between the UAS and the recurrent laryngeal nerve and parathyroid glands. Consequently, ligatures were often used at the areas marked by dotted lines.

Figure 2. Trial profile.