Study on the Efficacy of Infiltration of Upper Cluneal Nerves in Chronic Pain Related to Cluneal Syndrome

Study on the Efficacy of Infiltration of Upper Cluneal Nerves in Chronic Pain Related to Cluneal Syndrome

Lower back pain is a very common complaint in the Chronic Pain Clinic. Its etiology is nonspecific in 85% of the cases. In 1957, Strong and Davila reported that the superior cluneal nerves (SCNs) and middle cluneal nerves (MCNs) can be entrapped around the iliac crest, suggesting a causal relationship between this entrapment (SCN-Entrapment, SCN-E) and low back pain symptom. This is known today as "cluneal syndrome".

Cluneal syndrome remains poorly investigated and is currently a diagnostic challenge. Various types of lumbar movements exacerbate its occurence. The most common theory regarding the origin of this pain evokes that is primarily due to a mechanical cause linked to stenosis or adhesions of fibrous tissue around the cluneal nerves causing distress.

The hypothesis is that the investigator can reduce the pain related to the syndrome of superior cluneal origin thanks to a "volume effect" which aims to detach adhesions and/or aponeurotic stenoses that cause a distress of cluneal nerves.

The aim of this study is to assess the effectiveness of the cluneal nerve block using theThomas Dahl Nielsen ultrasound based technique in patients with chronic low-back pain related to SCN-E. To this end, the investigator will compare physiological serum injection versus local anaesthetic injection, with the aim of reducing short-term pain and improving quality of life.

Inclusion Criteria:

1. Patient signed Inform Consent
2. Patient diagnosed with unilateral or bilateral superior cluneal syndrome :

Diagnostic points will be :

• a maximum pain at the trigger point on the back iliac crest, approximately 7 cm from the median line and 4.5 cm from the poster superior iliac crest. Palpation on this point causes pain reminding the patient's long-term pain),
• Palpation "rolled-palpated" at the buttocks provokes either pain, paraesthesia, or discomfort.
• The criteria of facial syndrome, sacro-iliac syndrome or radiculopathy are excluded.
• Low back pain during back movements.

Exclusion Criteria:

1. Pain not associated to superior cluneal syndrome.
2. Infection at the puncture point.
3. Pain of suspected neoplastic origin.
4. Allergy to local anaesthetics.
5. Refusal of the patient