Introduction:
The introduction of sugammadex has created new opportunities for a quick reversal of relaxation caused by steroid relaxants.

Aim:
The objective of this study was to compare relaxation of striated muscles in laryngeal microsurgery depending on the applied agent: mivacurium or rocuronium.

Material and methods:
65 low-risk surgery patients were randomly divided into two groups: MIV (n = 32) and ESM (n = 33) before the scheduled larynx microsurgery. The MIV group used mivacurium to relax the muscles, the ESM group used rocuronium.The following parameters were monitored: pulse rate, arterial blood pressure, arterial blood saturation, ventilation parameters according to the conventional standards and the depth and rate of neuromuscullar blockade (NMB) reversal. The demand for anesthetics and analgesics used during the anesthesia and the frequency of complication occurrence were evaluated.

Results and discussion:
There were no differences under intubation conditions. The conditions of the operation assessed by its operator were better in the ESM group. The time of the operation was similar in the two groups. The acting time of sugammadex in the ESM group was on average 1 minute. The ESM group reached train-of-four ratio (TOFR) of 0.9 (90% recovery of NMB) far more quickly than the MIV group. There was no statistical difference in side effects.

Conclusions:
It seems to be reasonable to replace mivacurium with rocuronium and reverse its action by means of sugammadex in patients with a positive family history of allergy and anaesthetized for short-term operations or operations of unpredictable duration.