Atlanto-occipital catheterization of young rats for long-term drug delivery into the lumbar subarachnoid space combined with in vivo testing and electrophysiology in situ.

BACKGROUND: Catheterization has been widely used in neuroscience and pain research for local drug delivery. Though different modifications were developed, the use of young animals for spinal catheterization remains limited because of a little success rate. A reliable technique is needed to catheterize young animals aimed for in vivo testing combined with spinal cord electrophysiology, often limited by animal age, to facilitate pain research. NEW METHODS: We describe intrathecal catheterization of young rats (3-week-old) through atlanto-occipical approach for long-lasting drug delivery into the lumbar subarachnoid space. The technique represents a surgical approach of minimized invasiveness that requires PE-10 catheter and few equipment of standard laboratory use. RESULTS: Behavioral assessments revealed that spinal catheterization does not change peripheral sensitivity of different modalities (thermal and mechanical) and gives no rise to locomotive deficit or anxiety-like behavior in young rats. The long-term administration of genetic material (oligodeoxynucleotides given up to 4days), examined both in vivo and in situ, produced no adverse effects on basal peripheral sensitivity, but changed the AMPA receptor-mediated currents in sensory interneurons of the spinal cord. COMPARISON WITH EXISTING METHODS: Dissimilar to already described methods, the method is designed for the use of young rats for behavioral testing in vivo and/or spinal cord electrophysiology in situ. CONCLUSIONS: A practical method for spinal catheterization of young animals designed for studies in vivo and in situ is proposed. The method is rapid and effective and should facilitate investigation of therapeutic effects on both systemic and subcellular levels, as an advantage over the existing methods.

Effectiveness of intra-articular steroid injection for atlanto-occipital joint pain.

OBJECTIVES: The aims of this study were to evaluate the role of intra-articular joint injection for atlanto-occipital (AO) joint pain and to determine pain referral sites from that joint. DESIGN: Prospective observational study. METHOD: We evaluated 29 patients with chronic refractory neck pain and/or headache, and limited range of lateral bending with rotation at the AO joint on physical examination. Of the 24 patients who consented to undergo diagnostic injections, 20 patients had at least 50% relief from pain and underwent two AO intra-articular injections of mixture of local anesthetic and steroid approximately 1 week apart. Patients completed pain drawings, visual analog scales (VASs) for pain, and neck disability index (NDI) for level of function. Patients were evaluated for 2 months after the first injection. RESULT: There was headache in 14/20 (70%), posterior neck pain (PNP) in 20, and referred pain in 17 (85%). The average VAS values for headache, PNP, and other referred pains were reduced significantly from 5.64, 5.70, and 5.41, respectively, before treatments to 0.64, 2.30, and 1.71, respectively, two months after injection (P < 0.01). The average NDI value was reduced significantly from 39.95% at pretreatment to 20.40% at 2 months after treatment (P < 0.01). CONCLUSION: AO intra-articular steroid injection appears effective for the short-term control of chronic refractory pain arising from the AO joint.

Upper cervical facet joint and spinal rami blocks for the treatment of cervicogenic headache.

OBJECTIVE: To evaluate the efficacy of upper cervical facet joint injections and spinal rami blocks in the treatment of cervicogenic headache. BACKGROUND: Cervicogenic headache has been recognized as a common and often disabling disorder. The treatment of this headache type remains challenging. METHODS: We conducted a retrospective chart review of 31 patients with refractory cervicogenic headache who underwent fluoroscopically guided C(1/2), C(2/3) facet joint injections and C(2), C(3) spinal rami blocks using a mixture of 0.25% bupivacaine and 3 mg betamehtasone. The outcome measures were the change in headache severity, assessed using an 11-point numerical pain scale, after treatment, and the duration of head pain relief. RESULTS: Twenty-eight (90.3%) patients experienced >50% headache relief after treatment, with an average duration of 21.7 (1-90) days. Mean (+/-SD) head pain intensity decreased from 7.5 +/- 1.3 before treatment to 2.7 +/- 1.9 immediately after it (P < .0001). The procedures were well tolerated. CONCLUSIONS: C(1/2), C(2/3) facet joint injections and C(2), C(3) spinal rami blocks were effective and well tolerated for the treatment of cervicogenic headache in this study. The procedures provided significant and prolonged pain relief in the majority of patients. Larger controlled studies are needed to further evaluate the efficacy of this treatment modality in cervicogenic headache.

Atlanto-occipital joint pain. A report of three cases and description of an intraarticular joint block technique.

BACKGROUND AND OBJECTIVES: The atlanto-occipital (AO) joint is a true, innervated synovial joint with the potential to cause pain. METHODS: A detailed description of an AO joint injection technique is provided, as none was found on review of the literature. RESULTS: Using this technique, three illustrative cases provide preliminary evidence that intraarticular injection of the AO joint may have both diagnostic and therapeutic value for the treatment of upper cervical pain and headaches. CONCLUSIONS: Although AO joint injections may prove to be an effective adjunct to more traditional forms of conservative treatment, additional prospective studies are needed to better define the role of intraarticular AO joint injections in the diagnosis and treatment of head and neck pain.