The surgical approach has changed.

A double blind prospective randomized controlled trial in which the effect of single shot levobupivacaine 0,25% will be compared with the effect of levobupivacaine 0.25% in association with dexmedetomidine when performing an ultrasound guided modified pectoral nerve block , in patients undergoing a mastectomy with axillar procedure.

The difference in effect will be evaluated by monitoring the postoperative morphine consumption in both groups .

The hypothesis is that there is a significant decrease in morphine consumption during the first 24h postoperatively due to association of dexmedetomidine to the local anesthetic compared to the local anesthetic alone when performing a ultrasound guided modified pectoral nerve block. The morphine consumption will be the primary outcome parameter.

Women (18+, American Society of Anesthesiologists 1,2,3) undergoing a mastectomy with axillar procedure will be randomised and receive a ultrasound guided modified pectoral nerve block, if participants meet in- and exclusion criteria and provide written informed consent.

Using a two needle approach, ten milliliters of local anesthetic is injected under ultrasound guidance between the major and minor pectoral muscle and twenty milliliters between the minor pectoral and the serratus anterior muscle, on the side to be operated.

Participants receive intravenous Patient Controlled Analgesia with morphine and dehydrobenzperidol (1mg/ml morphine, 50µg dehydrobenzperidol/ml).

Furthermore every participant in the trial will receive ketorolac 0.5mg/kg three times a day and paracetamol four times 1g per day.

When the analgesia using the intravenous Patient Controlled Analgesia regime isn't sufficient, the anesthesiologist will titrate with morphine until pain free using a protocol (a bolus of 2mg morphine IV every ten minutes until pain free).

Inclusion Criteria:

• women,
• 18years and older
• American Society of Anesthesiologists 1, 2,3,
• planned for radical mastectomy.

Exclusion Criteria:

• Neurological problems (central and peripheral)
• Bilateral mastectomy
• Body Mass Index > 33,
• Absolute contra-indication for ketorolac.
• Allergy/over-sensitiveness to levobupivacaine or local anesthetics of the same class
• Allergy/over-sensitiveness to dexmedetomidine or other alpha2 agonists (clonidine)
• Anatomic variations of the breast, pectoral region or axilla, noticed at clinical examination, including a pacemaker, Implantable Cardioverter Defibrillator, Port-a-Cath or other implantable device on the side that needs surgery.
• Participation in an other clinical trial within a period of four weeks before the beginning of this trial.
• Coagulopathy
• Infection or abcess in the region where the Block will be placed.
• Pregnancy