Efficacy of corticoïd Infiltration Via Sacro-coccygien Hiatus in Discal Sciatica

The specific aim of this study is to determine whether a medical intervention improve status of patients with discal sciatica and if yes which type of intervention.

The primary criteria is to determine the difference between the mean leg pain during the latest 24 hours preceding the infiltration and the mean leg pain preceding the visit S4 (visit 4 weeks after the infiltration). If difference is of 50% patient will be considered "improved". This study will be organized under three steps:Step 1 : when 124 patients will be randomized: first intermediate analysis to compare efficacy of groups 1+ 2+ 3 versus 4. If significant difference is not demonstrated, study will be stopped at this stage since having demonstrating that infiltration or simulation is inefficient. On the other case, step 2 will be performed.Step 2 : Recruitment is continued only in arms 1 to 3 until reaching a total of 142 randomized patients. Second intermediate analysis to compare efficacy of groups 1+ 2 versus 3. If significant difference is not demonstrated, study will be stopped at this stage since having demonstrating that infiltration is inefficient. On the other case, step 3 will be performed.Step 3 : Recruitment is continued only in arms 1 and 2 until reaching a total of 274 randomized patients. Third intermediate analysis to compare efficacy of groups 1 versus 2.

Visit of inclusion (J0): 1/ notification in the case report form of - information concerning patient pain (mean, maximal and minimal pain during the 24 last hours)- Oswestry questionnaire - impact of discal sciatica on professional activity,- intake of analgesic, co-analgesics and non steroids anti- inflammatory drugs2/ Randomization and infiltration with corresponding treatment arm3/ Thirty minutes after receiving the infiltration, recording of actual patient pain Visits at day 7, weeks 4, 12 and 24 after J0: Notification in the case report form of - information concerning patient pain (mean, maximal and minimal pain during the 24 last hours)- Oswestry questionnaire - impact of discal sciatica on professional activity,- intake of analgesic, co-analgesics and non steroids anti- inflammatory drugs

Eligibility Criteria:
Inclusion Criteria:

* Adult with age equal or above to 18.
* Subject affiliated to French health insurance (Sécurité Sociale)
* Sciatic pain evolving since more than 1 month and less than 3 months
* Leg irradiation (pain above the knee)- True Lasègue- Mean leg pain during the latest 24 hours above 40 on an analogic visual scale (from 0 to 100)
* Pain induced by palpation in regards to the neo-articulation
* Pain not relieved by medical treatment with non steroids anti- inflammatory drugs or antalgics No sign of seriousness : no motor deficiency (muscular testing above or equal to 4 on an international scale (from 0 to 5), no sphincter deficiency, mean leg pain during the latest 24 hours below 80 on an analogic visual scale (from 0 to 100).
* Scanner of MRI since less than 3 months confirming discal hernia L4L5 or L5S1 in accordance with the clinic.
* Informed consent form signed

Exclusion Criteria:

* Age below 18
* Clinical arguments in favour of a non discal origin- Pregnant women
* Diabetic patient- Past history of diverticulosis complicated with severe arterial hypertension- Patient unable to understand the protocol
* No autonomy for coming to the hospital (no budget allocated for patient transportation)
* Hypersensitivity to local anesthetics with "liaison amide"-Hypersensitivity to one of the components-Porphyria
* Local or generalized infection, suspicion of infection
* Severe troubles of coagulation, anti-coagulant treatment taken- Imaging non concording
* Past history of infiltration via the sacro-coccygien hiatus
* Past history of lombar rachis surgery- Body mass index above 40.
* Intake of "b-bloquants"- Intake of antiarrythmics possibly giving "torsades de pointe" ("amiodarone, disopyramide, quinidiniques, sotalol,...)"-"Cimétidine" used at doses above or equal to 800mg/day.