Levobupivacaïne (Chirocaine®) is a new local anaesthetic recently marketed in France. The goal of this prospective work is to study the pharmacokinetic aspect of this drug after injection around the sciatic nerve (subgluteal way).

The originality of this work is to call upon a modelling of pharmacokinetic by using the principle of the pharmacology of population.

This work also proposes to appreciate a dynamic aspect since data of effectiveness and tolerance will be collected with regular intervals during the first 24 hours after the beginning of the study.

Inclusion Criteria:

• Surgical pathology of the leg or the foot with garot tyre of thigh
• Age included between 6 months and 12 years
• Status ASA I or II

Exclusion Criteria:

• Bilateral or one-sided surgical gesture realized without garot tyre
• Cutaneous infection in the point of draining
• Clinical confusion of the coagulation
• Allergy informed in the local anesthesics of amino-acid class
• Evolutionary neurological pathology of the operated limb
• Renal, respiratory, cardiac or hepatic insufficiency.