The aim of the study is to compare anaesthesia (for back surgery) using endotracheal intubation (patients anaesthized in the supine position)with anaesthesia using a laryngeal mask (anaesthesia induced and the laryngeal mask placed with the patient in the prone position on the operation table) as regards advantages, adverse effects and time spent. The anaesthesia in the 2 groups of patients is identical (propofol, remifentanil, rocuronium). Two groups of 70 pt. each are included in the stud. The inclusion criterias are patients 18-70 yrs., ASA group 1-2, normal airways, patients scheduled for back surgery with an estimated duration of less than 2 hours.

Adverse effects (related to the placement on the operation table i.e. pain in the arms or shoulders, pain in the throat, blood in the sputum, irritation in the eyes etc.) and time spent with all the procedures (anaesthesia, placement of the airway, surgery and emergence from the anaesthesia are registered. The hypothesis is that the method using the laryngeal mask is faster and with fewer adverse effects.

Inclusion Criteria:

• Patients scheduled for backsurgery of an espected duration less than 2 hours,
• Age 18-70 years,
• ASA (american society of anaaesthesiology) class 1-2,
• Normal airways

Exclusion Criteria:

• Body mass index >35
• Expected time of surgery > 2 hours