Background: Previous research indicates that application of 5-mm harmonic shears rather than diathermia significantly reduces operation time in transanal endoscopic microsurgery (TEM). Frequently, however, additional instruments were required to complete resection. We investigated whether the new 5-mm harmonic long shears (H-LS) are better equipped for TEM compared with regular harmonic shears (HS).
Methods: Between 2001 and 2006, 162 tumors (117 adenomas, 42 carcinomas, and 3 other tumors; mean distance 6.6 cm, mean area 40 cm(2)) were excised in 161 patients (82 men, 79 women; mean age 66 years).
Results: Eighty-eight resections were performed with HS and 74 with H-LS. Tumor and patient characteristics were similar except for specimen area. Tumors resected by H-LS were on average smaller than those resected by HS (34.4 versus 44.1 cm(2); Mann-Whitney U-test: p = 0.027). Mean operation time was 48 min and proportional to area in both groups (univariate analysis of variance p < 0.001). Mean operation time was 54 min using HS and 41 min using H-LS (t-test: p < 0.001). After correction for area, operation time for H-LS was reduced by 14% compared with HS (t-test: p < 0.001). H-LS is singly capable of completing resection in 88% compared with 26% for HS (Mann-Whitney U-test: p < 0.001). Mean blood loss was 16 cc for HS and 3 cc for H-LS (p < 0.001). Morbidity (11%) and mortality (0.6%) were not different between the two groups (Fisher's exact test).
Conclusion: Performing transanal endoscopic microsurgery with 5-mm harmonic long shears reduces operation time compared with regular shears, and completing resection seldom requires other instruments.