Ultracision Harmonic Scalpel and multifunctional tem400 instrument complement in transanal endoscopic microsurgery: a prospective study.

Background: For transanal endoscopic microsurgery, the ultracision Harmonic Scalpel (UC) and the multifunctional TEM400 instrument (T400) seem advantageous. This study investigated their clinical use.
Methods: Prospective analysis of tumor, patient, and operation characteristics was performed for 196 tumor resections per instrument intended for application.
Results: The T400 instrument was applied in 162 operations, and the UC in 34 operations. Tumor and patient characteristics were similar except for tumor area (respectively, 7.5 and 17 cm(2); p = 0.003). Operative time was proportionate to the tumor area (p < 0.001) and inversely proportionate to its distance from the dentate line to the lower margin of the tumor of the UC (p = 0.002). Application reduced operative time by 26% (p = 0.02, corrected for area). Whereas, T400 was always singly sufficient for excision, the UC required T400 application in 50% of operations, especially for larger tumors (p = 0.026), with the result that more rectal wall circumference was captured (p = 0.043). Both groups had similar safety parameters.
Conclusions: The UC substantially reduced operative time compared with the T400, but frequently required the T400 for procedure completion. The T400 is always singly sufficient.