In a randomized controlled crossover study design, ultrasound guided lumbar plexus blocks will be performed with and without the aid of a needle tip tracking (NTT) system. Specialists in anaesthesiology with average experience in ultrasound guided peripheral nerve block (PNB) techniques will perform the blocks. 27 volunteers will be included. The primary objective is to investigate the effect of the NTT system on performance time, as a measure for improved block performance. Secondary objectives are the effects of the NTT system on dexterity, peripheral nerve block characteristics, subjective experience, and peripheral block performance.

Inclusion Criteria:

• American Society of Anesthesiologists (ASA) physical status 1 or 2
• Volunteers that have given informed written consent

Exclusion Criteria:

• BMI < 18 kg/m2
• BMI > 35 kg/m2
• Body weight > 95 kg
• Volunteers that cannot cooperate during the examination
• Volunteers that do not speak or understand Norwegian language
• Volunteers with neurologic disease, nerve- or vascular impairment
• Volunteers with known coagulopathy
• Volunteers that are allergic to Lidocaine or other local anaesthetic agents
• Medications at the investigators discretion
• Volunteers with concomitant medical treatments interfering with PNB treatment
• Skin disease or infection affecting the whole-body surface or within the area of examination
• Any reason why, in the opinion of the investigators, the volunteer should not participate
• Subject participates in a potentially confounding drug or device trial during the course of the study
• Pregnancy and lactation period
• Women of childbearing potential who do not use an effective and secure method for birth control