Magnesium's Potential Role in Managing Chronic Pain
Several researchers have suggested a role for magnesium (Mg) in the management of chronic pain, a complex health problem with few highly effective treatments. A recent review of those studies indicates there is enough evidence of efficacy in those trials to merit further study to better define the role magnesium could play in managing several kinds of chronic pain.
The authors of this review examined the evidence for the efficacy and safety of magnesium in chronic pain. They included 9 randomized controlled trials including 418 participants. These trials compared Mg (at any dose, frequency, or route of administration) with placebo using participant pain measures.
Studies examined neuropathic pain (62 participants), migraines (190 participants), complex regional pain syndrome (86 participants), and low back pain with a neuropathic component (80 participants).
The heterogeneity precluded meta-analysis, and the authors could not make a judgment about safety because adverse events were inconsistently reported across the trials they reviewed. Moreover, evidence of analgesic efficacy was equivocal.
However, the authors concluded that efficacy signals in some of the included trials provide a rationale for more definitive studies to better define the role of magnesium in the management of chronic pain. (See Park R, Ho A, Pickering G, et al. Efficacy and safety of magnesium for the management of chronic pain in adults: a systematic review [published online ahead of print February 10, 2020]. Anesth Analg. doi:10.1213/ANE.0000000000004673.)
Degenerative Spine Disease in the Elderly: Narcotic Use After Surgery
The authors investigated individuals older than 66 years who underwent spine surgery for degenerative disease. Of the 14,583 Medicare enrollees they studied, 6% continuously used opioids 1 year after surgery.
The researchers stratified the use of narcotics into those who received opioids preoperatively and those who were opioid-naive. Rates of continuous use at 1 year postsurgery were 0.3% in opioid-naive patients and 23.6% in those who used opioids in all 4 quarters before surgery. Also, benzodiazepine use within the year before surgery and Medicaid dual-eligibility were associated with prolonged opioid use.
Given that the preoperative use of opioids was the strongest predictor of chronic, prolonged use, the authors reached 3 conclusions:
1. Use of nonopioid alternatives is underutilized;
2. There may be delay in referral to spine centers; and
3. Opioids for noncancer pain may be overprescribed.
(See Nguyen A. Ross E, Westra J, et al. Opioid utilization in geriatric patients after operation for degenerative spine disease [published online ahead of print February 21, 2020]. J Neurosurg Anesthesiol. doi:10.1097/ANA.0000000000000682.)
Spinal Cord Stimulation Effective for Chronic Pain and CRPS
An international, interdisciplinary work group conducted literature searches, reviewed abstracts, and selected studies to grade the evidence for spinal cord stimulation (SCS) as effective therapy for pain. Criteria included randomized controlled trials (RCTs) of patients with intractable pain of greater than 1 year in duration. Retrospective studies and those with small numbers or only abstracts were excluded.
Two observers graded the full studies using the modified Interventional Pain Management Techniques: Quality Appraisal of Reliability and Risk of Bias Assessment, the Cochrane Collaborations Risk of Bias assessment, and the US Preventive Services Task Force level-of-evidence criteria.
The investigators found Level 1 evidence (strong) that SCS was effective for axial back/lumbar radiculopathy or neuralgia (5 high-quality RCTs) and complex regional pain syndrome (CRPS; 1 high-quality RCT).
The researchers concluded that high-level evidence supports SCS for treating chronic pain and CRPS. Moreover, for patients with failed back surgery syndrome, SCS was more effective than reoperation or medical management.
Further study is indicated to determine whether new stimulation waveforms and frequencies may provide a greater likelihood of pain relief compared with conventional SCS for patients with axial back pain, with or without radicular pain. (See: Deer TR, Grider JS, Lamer TJ et al, A systematic literature review of spine neurostimulation therapies for the treatment of pain. Pain Med. 2020 Feb 8. pii: pnz353. doi: 10.1093/pm/pnz353.)