Combination Intrathecal Drug Therapy Strategies for Pain Management.

BACKGROUND: Numerous combination intrathecal drug therapy (CIDT) strategies exist and are utilized for varying pain syndromes, typically when monotherapy dose escalation or medication alternation is deemed untenable or unfeasible. Unfortunately, the supportive evidence basis for the use of these strategies and specific drug combinations is generally lacking and unclear, with many medications being used for off-label indications. OBJECTIVE: In this manuscript, we provide a robust exploration and analysis of the literature to provide an evidence-based narrative for the use of CIDT strategies in regard to clinical indications, pharmacologic parameters, specific drug combinations, safety profiles, and future directions. STUDY DESIGN: Narrative review. METHODS: This was an evidence based narrative performed after extensive review of the literature. RESULTS: Variances in intrathecal pharmacokinetics and pharmacodynamics are utilized advantageously with CIDT strategies to achieve improved analgesic benefit; however, appropriate use may be limited by increased or compounded risk of adverse effects. The supportive evidence for CIDT use for chronic pain conditions is largely lacking and limited to small, uncontrolled, observational studies, with many having various confounding factors, including a lack of standardized dosing. The most evidenced CIDT strategies include polyanalgesia with morphine-ziconotide, opioid-clonidine, and morphine-bupivacaine. Notably, in addition to pain relief, morphine-bupivacaine has been shown to decrease early opioid escalation requirements. LIMITATIONS: The supportive evidence for CIDT use for chronic pain conditions is largely lacking and limited to small, uncontrolled, observational studies, with many having various confounding factors including a lack of standardized dosing. CONCLUSIONS: CIDT strategies and polyanalgesia combinations can be effective for treating various patient populations with chronic pain. The appropriate use of these strategies may be limited by increased or compounded risk of adverse effects, both of which are highly patient and scenario dependent. Therefore, practitioners should maintain a particularly low threshold of suspicion for adverse effects in patients with CIDT such that safety profiles associated with this therapy can be favorably maintained.

The Impact of Local Steroid Administration on the Incidence of Neuritis following Lumbar Facet Radiofrequency Neurotomy.

BACKGROUND: Pain arising from the lumbar facet joints is a common cause of axial back pain in adults. Radiofrequency neurotomy (RFN) of the medial branches of the spinal dorsal rami has been used as a treatment option. The most common side effect is transient, localized, burning, neuritic-type pain, termed post-neurotomy neuritis (PNN). Corticosteroids have been administered through the radiofrequency cannula after neurotomy to prevent PNN, but no study has examined the effects of this on PNN. OBJECTIVES: We investigated the incidence of PNN in patients who received corticosteroids after RFN and in those patients who did not receive corticosteroids. STUDY DESIGN: Retrospective evaluation. SETTING: Single-site interventional pain management practice in an urban tertiary academic medical center. METHODS: One hundred and sixty-four patients were included in this study and were categorized into non-steroid (n = 87) and steroid (n = 77) groups. Patient's age, gender, body mass index (BMI), laterality of procedure, use of neuropathic pain medications, baseline pain, and duration of pain were all recorded. PNN was determined if the patient self-reported transient burning or neuropathic pain at the site prior to or at the 6-week routine follow-up encounter. RESULTS: There was no significant difference in demographic characteristics between the 2 groups in age, gender, baseline pain, and duration of pain. The proportion of patients in the steroid treated group with PNN was 5 out of 77 (6.4%) and the non-steroid group was 6 out of 87 (6.9%). There was no statistically significant difference between the groups. There was no statistically significant difference in the incidence in neuritis between individuals taking neuropathic agents and individuals not taking neuropathic agents. LIMITATIONS: This study has several limitations including small sample size, patients' self-reported neuropathic symptoms, and inability to draw strong conclusions due to the retrospective study design. A single interventionalist performed all the procedures in this retrospective study and variations in technique amongst others are inevitable. CONCLUSION: Administration of steroids after RFN does not reduce the incidence of post-neurotomy neuritis. Concurrently administering neuropathic medications does not protect against neuritis. KEY WORDS: Radiofrequency neurotomy, radiofrequency ablation, neuritis, corticosteroid, lumbar facet pain, post neurotomy neuritis.