For any regional anesthesia of the face, it is necessary to comply with the sedentary rules: realisation in a room dedicated to the anaesthesia, with a usual monitoring: electrocardiogram (ECG), non-invasive blood pressure (PNI), measurement continuous arterial oxygen saturation (SaO 2).

A plate with emergency drugs ready with employment must be present: Pentothal, midazolam. A written procedure is posted, in the event of toxic accidents with the anaesthetic solution, with the action to be taken immediate. It is only with this discipline that the incidents will be rare and the safety realisation. The rules published by the SFAR (French Society or Anaesthesia), concerning the peripheral blocks of the members also apply to the blocks of the face, in particular: consultation of anaesthesia with patient information, the monitoring and the place of realisation of the anaesthesia, premedication and venous way before the act, realisation with gloves and asepsis, injections slow and split [17].

The characteristics of the blocks of the face must be known. First of all vascular richness of the face (the surgeons frequently infiltrate the zone with a adrenalin solution to decrease the bleeding by it, genuine blood sponge, which will pose the risks of vascular breach and injection in a vessel; fast resorption of the anaesthetic solution with obvious toxic risk. The use of needle with short bevel with the advantage of being less aggressive for the vessels with the very slowly progressing.

The superposition of the territories [7] obliges to construct blocks wider than the strict surgical territory, and to rather construct sometimes a block at the origin of the nerve (maxillary, mandibular) than a too restrictive terminal section.

Pharmacology of local anaesthetics and additive drug (adjuvant)

The pharmacological characteristics on the level of the face are: vascular richness, the toxic risk, generally a sensitive block need only.

The vascular resorption of the anaesthetic solution is defined by the site of administration (the face is very vascularised), proportioning, the addition of a vasoconstrictor or another additive drug, and the pharmacological profile of the product [10]; thus the ropivacaine is interesting by its vasoconstrictives properties. This facial vascular richness as well as the fast resorption on the level of the mucous membranes exposes to the risk to reach the toxic plasmatic concentrations (CMax= toxic plasmatic concentration) in a short time (TMax= time to go at the CMax) [11]. Use recommended of additive drug associated with low volumes and low concentrations, strongly reduced this toxic plasmatic risk.

The additives drugs used are: adrenalin with 1/200.000, without exceeding 1 ml; the block will last longer and the operational bleeding per will be decreased. It is necessary to respect however reserve indication for the final arteries and the orbital cavity [10, 11]. The clonidine is also used with the amount of 0,5 µg. Kg-1 [12] and presents few side effects; it presents effects close to adrenalin except the vasoconstriction and can thus be used largely on the face.

The molecules of anaesthetic solution most largely used are:

• lidocaine 1% or 1.5% for short surgery (emergency, ambulatory)
• bupivacaine 0.25% to avoid for the neurological and cardiac toxic risk
• mepivacaine 1% or 1.5% for surgery of average duration; the characteristic has to diffuse well with the nervous structures, to be not very toxic, and to have a rather fast lifting of block (ambulatory)
• ropivacaine 0.5% and 0.75% for surgery of average duration and long postoperative analgesia; it is less toxic than the bupivacaine. and lends itself very well to the blocks of face ( good sensitive block, vasoconstrictive action)
• levobupivacaine intermediate between ropivacaine and bupivacaine, in the course of evaluation.

One can construct dissociative anaesthesia, or differential nervous block [11] on the level of the face, as on the level of the upper limb [13], if several territories are concerned. One can associate two anaesthetic solution (short local anaesthetic and long local anaesthetic) for a fast block of installation; once again it is strongly recommended the use of additive drug in particular the clonidine, which leaves the free surgeon make his infiltrations with adrenalin.

In conclusion for the blocks of the face it is necessary to retain, the use of small volumes of anaesthetic solution especially for a sensitive block, and the systematic use additive drug.

neurostimulation

Since more than one ten year, the neurostimulation became impossible to circumvent in the perform of the peripheral nervous blocks [14,15]; the blocks of face them also will find advantage there. Indeed safe for the really superficial blocks and of easy identification, this technique of location can improve the rate of success and decrease the incidents. That is particularly obvious for the deep blocks (block of "fossa'), like the mandibular block and the maxillary block. For the mandibular the existence of a motor branch will allow the search for an easily identifiable muscular answer. For the nerve exclusively sensitive maxillary, one will be able to call upon a sensitive stimulation, very seldom used to date, with research of dysesthesias in the selected territory; accordingly it will be necessary to have a neurostimulator [15] making it possible to lengthen the time of stimulation to 0,3 milliseconds [16], necessary to stimulate sensitive fibres.

In all the cases the traditional procedure of the neurostimulation must be observed [15]: to know to analyse the answer, to define the Minimal Intensity of Stimulation (IMS), not to inject too much close to the nerve (with too low intensities), to check the disappearance of the answer that it is driving or sensitive as of first millilitre (ml) injected. The advantages of this sensitive neurostimulation, in addition to the assistance with the location, are a better effectiveness, a reduction of the nervous lesions [16], an easier training especially on the level of the face.

ZONAL BLOCKS

For a complete anaesthesia of the external ear, 3 blocks should be associated: the auriculotemporal nerve block (2 ml), the great auricular nerve block (7 ml) and the lesser occipital nerve block (4 ml).

That will allow all the surgery of this zone that it is aesthetic, repairing (external ear plasties) or carcinologic surgery, frequently bilateral. Only the zone of Ramsay-Hunt [1] escapes these blocks.

The nasal teguments are blocked by the association of two bilateral blocks: infraorbital and nasal; all the surgery of surface can be made thus (tumours, rhinophyma) [20].

The simple bone surgery as the reduction of nasal fracture is practicable under block, very interesting in emergency (supratrochlear block, and nasal block) [20].

Finally the rhinoplasties will be able to profit from association general anaesthesia - blocks of the nose (infraorbital and nasal) for an excellent postoperative analgesia.

Within the framework of the care in urgency and wounds of cranium, one can propose a blocking of the innervation of the scalp; either by a semi-circumferential infiltration (2,7), or by three infiltrations blocking the terminal branches:

• in forehead (supraorbital nerve, supra- trochlear nerve with 5 ml);
• in lateral zone temporo-parietal (zygomatic nerve, auriculotemporal nerve with 5 ml),
• and in posterior zone (lesser and great occipital with 4 ml).