Comparaison entre l'infiltration para-vertébrale rétrolaminaire d'un mélange analgésique non-stéroïde et l'infiltration péridurale stéroïdienne chez les patients souffrant de douleurs radiculaires chroniques : une étude rétrospective

Chronic radicular pain is often treated by epidural steroid infiltration (ESI). In 2014 the Food and Drug Administration (FDA) issued a letter warning that the ESI may result in rare, but serious adverse events, including “loss of vision, stroke, paralysis, and death”. Based on several studies, the efficacy of ESI is not proven. In addition, after repeated ESI, the chance of iatrogenic adrenal dysfunction and hypercorticosteroid status will be increased. In this retrospective study, we compare retrolaminar paravertebral infiltration (RPVI) of a non-steroid-mixture with ESI. Objective: The main purpose of this project was to compared the efficacy of paravertebral infiltration (RPVI) with a mixture (morphine 1 mg, ketamine 10 mg, neostigmine 0.5 mg, naloxone 2 ng and bupivacaine 10 mg) and efficacy of epidural steroid infiltration (ESI) treatment. Method: We identified 31 patients registered in the Quebec Pain Registry suffering from chronic lumbar or cervical radicular pain who were referred to CHUM (Centre hospitalier de l’université de Montréal) pain clinic between 2009 and 2014. These patients received ultrasound-guided retrolaminar paravertebral infiltration (RPVI) with a mixture (7 mL) of morphine 1 mg, ketamine 10 mg, neostigmine 0.5 mg, naloxone 2 viii ng and bupivacaine 10 mg. The control group, matched by gender, age and DN4 sub-scale score at baseline, consisted of 31 patients with the same pathology. It was treated by fluoroscopic-guided ESI. The main pathologies in both groups were disc disorders and/or foraminal stenosis. All patients received only one infiltration during the six months following the initial visit. The visual analog scale (VAS) was assessed at the first visit and in six months. BPI, PCS and SF-12 were compared in both groups. Overall satisfaction in pain relief was assessed with a scale of 1 (very unsatisfied) to 6 (very satisfied) six months later. Results: The average VAS scores for the last seven days preceding the first visit and six months later were compared in both groups. The same comparison was made for overall treatment satisfaction. There is no significant difference in the VAS and in the satisfaction scores between the two groups. Discussion/conclusion: Chronic pain is a condition that affects about 20% of the adult population in Canada. Different medications and interventional approaches are used for chronic pain. All medications and procedures have relative efficacy and side effects. The most common side effects of ESI are adrenal dysfunction, iatrogenic hypercorticism, loss of vision, vascular accident, post puncture headache and paralysis. ix Analgesic medications have side effects. For example, the side effects associated with morphine include tolerance, hyperalgesia, allodynia, addiction, hypoventilation, apnea, somnolence, nausea and itching. Ketamine can cause delirium and stimulate the sympathetic system. Neostigmine increases hyperparasympathetic effects, such as nausea, bradycardia and arterial hypotension. Bupivacaine is a local anesthetic substance. Cardiac arrest after intravenous injection of bupivacaine is the most serious complication. Intrathecal injection of bupivacaine, if accidentally used in place of epidural infiltration, would lead to spinal anesthesia. Naloxone dose is very low and its side effects are rare. According to this study, the analgesic effects and the overall satisfaction of the patient evaluated 6 months after the first evaluation of the two intervention methods, retrolaminar and epidural infiltration, are equivalent. Based on the complications and side effects of ESI, the infiltration of RPVI with a non-steroidal mixture could be considered as an alternative method.

Keyphrases: Morphine, Naloxone, Retrospective study, Epidural steroid infiltration (ESI), Retrolaminar paravertebral infiltration (RPVI), Ketamine, Bupivacaine