Post-thoracotomy pain is one of the most severe. The local analgesia allows its effective control and a reduction of postoperative morbidity and mortality.

The gold standard for local analgesia is the thoracic epidural. However, this technique can be dangerous with severe complications.

The paravertebral block showed comparable efficacy to the thoracic epidural for local analgesia . In addition, it has a better safety profile. There are several installation techniques. The difference in efficiency of these laying techniques is unknown.

Compare the clinical effectiveness of two strategies of realization of paravertebral block: by the anesthetist before incision (paravertebral block guided by ultrasound) and by the thoracic surgeon at chest closure (paravertebral block visual).

Inclusion Criteria:

• patient with thoracotomy indication for segmentectomy (s), lobectomy (s) lung or pulmonary wedge resection
• patient consenting to participate to the study
• patient enrolled in the national healthcare insurance program
• patient older than 18 years

Exclusion Criteria:

• patient with neuropathy
• patient with body mass index superior to 35 kg/m2
• patient with contraindication for paravertebral block or local analgesia