Peripheral regional anesthesia is the current gold standard of opioid-sparing perioperative analgesia, especially in shoulder, upper limb, and leg surgery. Axillary brachial plexus nerve block is one possible block for upper limb surgery. Loss and return of sensation require time and loss of sensation is supposed to spread from the proximal part to the distal part of the upper limb. Interestingly, until now there is no study about the return of sensation related to the anatomic region.

The investigators hypothesize that the loss and return of sensation after axillary brachial plexus nerve block will first occur in the proximal part of the upper limb and last in the distal part.

Peripheral regional anesthesia is the current gold standard of opioid-sparing perioperative analgesia, especially in shoulder, upper limb, and leg surgery.(1-8) Axillary brachial plexus nerve block is one possible block for upper limb surgery.(4, 5, 9) Loss and return of sensation require time. It is known from clinical practice that loss of sensation occurs from the proximal part of the arm to the distal part of the upper limb.

Interestingly, until now there is no study about the return of sensation related to the anatomic region. The investigators hypothesize that return of sensation after axillary brachial plexus nerve block will develop in the same direction like loss of sensation, what means from proximal to the distal part of the upper limb.

Inclusion Criteria:

• Outpatients with planed surgery with axillary brachial plexus nerve block
• Informed consent as documented by signature
• Age ≥ 18 years

Exclusion Criteria:

• Patients with a known allergy towards the local anaesthetic

All outpatients undergoing upper limb surgery with axillary brachial plexus nerve block at Balgrist University Hospital will be eligible to take part in the project.