Nabilone and THC/CBD for the Treatment of FBSS Refractory Pain

Failed Back Surgery Syndrome (FBSS) is defined as: spinal pain of unknown origin either persisting despite surgical intervention or appearing after surgical intervention for spinal pain originally in the same topographical location. Several conditions have been identified as causes of FBSS: epidural fibrosis, canal stenosis (global or lateral), foraminal stenosis, retained disc fragment, recurrent disc herniation or degeneration, spinal instability, facet joint pain, sacroiliac joint pain, discitis, adhesive arachnoiditis and others. Can involve 20% to 40% of patients who have undergone lumbar spine surgery and 0.02% to 2% of the general population suffer from this syndrome. In FBSS symptoms are the persistence of low back pain, deterioration or recurrence of radiculopathy, sensory and/or motor deficit, sphincter dysfunction. Chronic opioid therapy does not improve long-term pain management. Similar issues can occur with conservative measures like peridural injections of steroids, intrathecal analgesic infusion and local anesthetics injections. Despite a large part of FBSS patients benefit of radio-frequency treatment and/or spinal cord stimulation (SCS), a small percentage of them doesn't report benefits. Pain could be treated by drugs modulating endocannabinoid system and it could represent a pharmacological option in a multimodal treatment approach for neuropathic pain. Authors present a retrospective case series documenting the efficacy and safety of oral administration of cannabinoids agonists (THC/CBD and nabilone) in 20 FBSS patients, presenting moderate to severe chronic pain that not responding to other treatment regimens. Cannabinoids agonists were administered in association with the practice of spinal cord stimulation (SCS). Other analgesic therapies were discontinued before the beginning of the treatment. The study was performed during the period between September 2014 and January 2016 and the duration was up to 12 months. Characteristics and severity of neuropathic pain were measured using the Douleur Neuropathique 4 questionnaire. The Brief Pain Inventory allows patients to rate the severity of their pain and the degree to which pain interferes with common dimensions of feeling and function. Patients aged between 45 and 69. All patients received a fixed dose of cannabinoid agonists: treatment was initiated with nabilone 1mg/day or an oleic suspension for oral administration of THC/CBD 25mg/day. The basal dose was increased depending on effects on pain control. Adverse reactions were treated by decreasing the subscripted dose. If adverse events required the suspension of the administration of the initially prescribed drug, the same was switched with the other available in the study.