Postoperative drain after transoral endoscopic thyroidectomy vestibular approach (TOETVA) with single incision

Objective To find the optimal size of a drain for the reliable drainage and the best cosmetic result in TOETVA. To explore the normal drainage flow rate after TOETVA. Methods A prospective randomized controlled trial was performed in a single center from December 2016 to December 2018. One hundred and fifty-three (153) patients had TOETVA with a single incision and were randomly divided into two groups. Self-made drainage tubes with a small diameter (outer diameter 2.0 mm, inner diameter 1.0 mm) were used in 80 patients (experimental group). No. 8 tubes were used in 73 patients (control group). The clinical characteristics and results between both groups were compared by t test or chi-square test, and the results of normal drainage flow rate were calculated. Results The experimental group had a longer intraoperative tube-inserting time, compared with the control group (9.5 +/- 2.5 min vs. 5.6 +/- 1.4 min, p = 0.001), a smaller scar six months after the operation (1.8 +/- 2.3 mm vs. 3.1 +/- 2.6 mm, p = 0.002), and a lower Vancouver Scar Scale score at both one month (3.20 +/- 1.44 vs. 4.19 +/- 1.92, p = 0.001) and six months after the operation(1.43 +/- 1.84 vs. 2.40 +/- 2.37, p = 0.006). The drainage volume, pain score on the first day, postoperative complications (tube blockage, air leakage, subcutaneous hydrops, hematoma, regional infection), and the extubation time were not significantly different. The average drainage of 148 patients without postoperative complications was 78.3 +/- 10.9 ml. The cumulative drainage within 8 h, and 32 h after the operation accounted for 53.2% and 91.9% of the total drainage, respectively. The residual drainage at 32 h was estimated to be 6.5 +/- 2.9 ml (P95 = 11.0 ml). A linear regression equation between total volume (V-t) and the size of resected tissue (S) was established: V-t = 1.625 S + 56.604 (p = 0.0001). Conclusion In TOETVA, a small drain can provide a good cosmetic appearance and reliable drainage. The main exudation period of the wound is within 8 h after the operation. If a residual volume of less than 11 ml is considered to be self-absorbable, the shortest safe extubation point for 95% of patients should be 32 h after the operation.