Corticosteroid Therapy in Acute and Subacute Arachnoiditis - A Case Series.

Arachnoiditis is difficult to treat. Patients are often left frustrated after many failed trials of conservative therapies without symptom resolution. Surgery may provide symptom relief for a short period of time, but their pain often returned. Herein, we present three cases of acute arachnoiditis following three different pain procedures: epidural blood patch, IDDS implant, and epidural steroid injection. The patients were diagnosed and treated with corticosteroids within 10 days of the procedure. Two patients were treated with the same oral steroid regiment, while the third patient was treated with both oral and IV steroid. All three patients had good outcomes at the completion of their steroid therapy. This case series may provide insight into treating acute and subacute arachnoiditis from pain interventions.

Quantitative assessment of painful diabetic peripheral neuropathy after high-frequency spinal cord stimulation: a pilot study.

OBJECTIVE: Randomized trials have demonstrated efficacy of spinal cord stimulation (SCS) for treatment of painful diabetic neuropathy (PDN). Preliminary data suggested that treatment of PDN with high-frequency SCS resulted in improvements on neurological examination. The purpose of the present study was to explore whether patients with PDN treated with high-frequency SCS would have improvements in lower-extremity peripheral nerve function. DESIGN: Prospective cohort study in an outpatient clinical practice at a tertiary care center. METHODS: Patients with PDN were treated with high-frequency SCS and followed up for 12 months after SCS implantation with clinical outcomes assessments of pain intensity, neuropathic symptoms, and neurological function. Small-fiber sudomotor function was assessed with the quantitative sudomotor axon reflex test (QSART), and large-fiber function was assessed with nerve conduction studies (NCS). Lower-extremity perfusion was assessed with laser Doppler flowmetry. RESULTS: Nine patients completed 12-month follow-up visits and were observed to have improvements in lower-extremity pain, weakness, and positive sensory symptoms. Neuropathy impairment scores were improved, and 2 patients had recovery of sensory responses on NCS. A reduction in sweat volume on QSART was observed in the proximal leg but not at other sites. No significant differences were noted in lower-extremity perfusion or NCS as compared with baseline. CONCLUSIONS: The improvement in pain relief was concordant with improvement in neuropathy symptoms. The findings from this study provide encouraging preliminary data in support of the hypothesis of a positive effect of SCS on peripheral neuropathy, but the findings are based on small numbers and require further evaluation. TRIAL REGISTRATION: ClinicalTrials.gov ID NCT03769675.

Comparative Effectiveness of Landmark-guided Greater Occipital Nerve (GON) Block at the Superior Nuchal Line Versus Ultrasound-guided GON Block at the Level of C2: A Randomized Clinical Trial (RCT).

OBJECTIVES: The purpose of this single center, prospective randomized controlled trial was to compare clinical outcomes between an ultrasound-guided greater occipital nerve block (GONB) at the C2 vertebral level versus landmark-based GONB at the superior nuchal line. METHODS: Patients with occipital neuralgia or cervicogenic headache were randomized to receive either a landmark-based GONB with sham ultrasound at the superior nuchal line or ultrasound-guided GONB at the C2 vertebral level with blinding of patients and data analysis investigators. Clinical outcomes were assessed at 30 minutes, 2 weeks, and 4 weeks postinjection. RESULTS: Thirty-two patients were recruited with 16 participants in each group. Despite randomization, the ultrasound-guided GONB group reported higher numeric rating scale (NRS) scores at baseline. Those in the ultrasound-guided GONB group had a significant decrease in NRS from baseline compared with the landmark-based GONB group at 30 minutes (change of NRS of 4.0 vs. 2.0) and 4-week time points (change of NRS of 2.5 vs. -0.5). Both groups were found to have significant decreases in Headache Impact Test-6. The ultrasound-guided GONB had significant improvements in NRS, severe headache days, and analgesic use at 4 weeks when compared with baseline. No serious adverse events occurred in either group. CONCLUSIONS: Ultrasound-guided GONBs may provide superior pain reduction at 4 weeks when compared with landmark-based GONBs for patients with occipital neuralgia or cervicogenic headache.

Ultrasound-guided transversus abdominis plane block vs trigger point injections for chronic abdominal wall pain: a randomized clinical trial.

ABSTRACT: The primary aim of this randomized clinical trial is to investigate the effects of ultrasound-guided transversus abdominis plane (TAP) vs ultrasound-guided trigger point injections (TPIs) on numerical rating scale pain scores at month 3 follow-up in patients with a chronic abdominal wall pain. The primary outcome measure was the difference in mean numeric rating scale pain scores between the TAP and TPI groups at month 3 in an intent-to-treat (ITT) analysis. A total of 60 patients were randomized 1:1 to receive an ultrasound-guided TAP block (n = 30) or an ultrasound-guided TPI (n = 30). No significant group differences in baseline demographic or clinical characteristics were observed. The mean baseline pain score for the TAP and TPI groups was 5.5 and 4.7, respectively. In the ITT analysis at month 3, the between-group difference in pain scores was 1.7 (95% confidence interval, 0.3-3.0) favoring the TPI group. In a secondary per-protocol analysis, the between-group difference in pain scores was 1.8 (95% confidence interval, 0.4-3.2) favoring the TPI group. For the ITT and per-protocol analyses, the group differences in pain scores were consistent with a medium effect size. The main finding of this randomized clinical trial is that adults with chronic abdominal wall pain who received a TPI reported significantly lower pain scores at month 3 follow-up compared with patients who received a TAP block.

Spinal Cord Stimulation for Neuropathic Pain Treatment in Brachial Plexus Avulsions: A Literature Review and Report of Two Cases.

BACKGROUND: At least 50% of individuals who suffer a brachial plexus avulsion (BPA) will develop chronic pain, frequently more debilitating than their functional limitations. Similar to other neuropathic pain states, BPA pain is often refractory to pharmacological agents. Despite spinal cord stimulation (SCS) first being used for BPA in 1974, there have been no published literature reviews examining the current evidence of SCS for the treatment of neuropathic pain following BPA. In addition to a clinical review of the literature for this indication, we also share our experience with high-frequency SCS (HF-SCS) for BPA-related pain. METHODS: MEDLINE and EMBASE databases were searched. All published articles including at least one BPA individual treated with SCS for pain treatment were included. RESULTS: The initial search identified 288 articles, of which 13 met inclusion criteria for a total of 41 patients. These patients were primarily male and underwent SCS with reported improved pain scores. CASE REPORTS: HF-SCS leads were percutaneously placed in two male patients who suffered BPA from traumatic injuries. At follow-ups of 13 and eight months, respectively, both patients continued to report an improvement in their pain. CONCLUSIONS: Despite published reports showing benefit for pain control in patients with BPA, the overall low quality, retrospective evidence included in this review highlights the need for a rigorous prospective study to further address this indication.

Pain and the immune system: emerging concepts of IgG-mediated autoimmune pain and immunotherapies.

The immune system has long been recognised important in pain regulation through inflammatory cytokine modulation of peripheral nociceptive fibres. Recently, cytokine interactions in brain and spinal cord glia as well as dorsal root ganglia satellite glia have been identified important- in pain modulation. The result of these interactions is central and peripheral sensitisation of nociceptive processing. Additionally, new insights and the term 'autoimmune pain' have emerged through discovery of specific IgGs targeting the extracellular domains of antigens at nodal and synaptic structures, causing pain directly without inflammation by enhancing neuronal excitability. Other discovered IgGs heighten pain indirectly by T-cell-mediated inflammation or destruction of targets within the nociceptive pathways. Notable identified IgGs in pain include those against the components of channels and receptors involved in inhibitory or excitatory somatosensory synapses or their pathways: nodal and paranodal proteins (LGI1, CASPR1, CASPR2); glutamate detection (AMPA-R); GABA regulation and release (GAD65, amphiphysin); glycine receptors (GLY-R); water channels (AQP4). These disorders have other neurological manifestations of central/peripheral hyperexcitabability including seizures, encephalopathy, myoclonus, tremor and spasticity, with immunotherapy responsiveness. Other pain disorders, like complex regional pain disorder, have been associated with IgGs against ß2-adrenergic receptor, muscarinic-2 receptors, AChR-nicotinic ganglionic α-3 receptors and calcium channels (N and P/Q types), but less consistently with immune treatment response. Here, we outline how the immune system contributes to development and regulation of pain, review specific IgG-mediated pain disorders and summarise recent development in therapy approaches. Biological agents to treat pain (anti-calcitonin gene-related peptide and anti-nerve growth factor) are also discussed.

Procedural predictors of epidural blood patch efficacy in spontaneous intracranial hypotension.

BACKGROUND AND OBJECTIVE: Epidural blood patch (EBP) is a safe and effective treatment for spontaneous intracranial hypotension (SIH), but clinical and procedural variables that predict EBP efficacy remain nebulous. METHODS: This study is an institutional review board-approved retrospective case series with dichotomized EBP efficacy defined at 3 months. The study included 202 patients receiving 604 EBPs; iatrogenic cerebrospinal fluid leaks were excluded. RESULTS: Of the EBPs, 473 (78%) were single-level, 349 (58%) lumbar, 75 (12%) bilevel, and 56 (9%) multilevel (≥3 levels). Higher volume (OR 1.64; p<0.0001), bilevel (3.17, 1.91-5.27; p<0.0001), and multilevel (117.3, 28.04-490.67; p<0.0001) EBP strategies predicted greater efficacy. Only volume (1.64, 1.47-1.87; p<0.0001) remained significant in multivariate analysis. Site-directed patches were more effective than non-targeted patches (8.35, 0.97-72.1; p=0.033). Lower thoracic plus lumbar was the most successful bilevel strategy, lasting for a median of 74 (3-187) days. CONCLUSIONS: In this large cohort of EBP in SIH, volume, number of spinal levels injected, and site-directed strategies significantly correlated with greater likelihood of first EBP efficacy. Volume and leak site coverage likely explain the increased efficacy with bilevel and multilevel patches. In patients with cryptogenic leak site, and either moderate disability, negative prognostic brain MRI findings for successful EBP, or failed previous lumbar EBP, a low thoracic plus lumbar bilevel EBP strategy is recommended. Multilevel EBP incorporating transforaminal administration and fibrin glue should be considered in patients refractory to bilevel EBP. An algorithmic approach to treating SIH is proposed.

Amyotrophic lateral sclerosis and anesthesia: a case series and review of the literature.

PURPOSE: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that leads to death due to respiratory failure. This report describes the perioperative characteristics of ALS patients who underwent procedures with anesthesia at our institution. METHODS: We reviewed perioperative records of ALS patients who underwent procedures with anesthesia from January 1, 2014, through December 31, 2015. RESULTS: Seventy-eight patients underwent 89 procedures (71 procedures with monitored anesthesia care and 18 with general anesthesia), including 45 gastrostomy tube placements and 18 bone marrow biopsies. Three patients had prolonged duration of postoperative intubation related to preexisting respiratory muscle weakness, and one patient with bilateral pneumothorax required tracheal reintubation for respiratory distress. Four patients had prolonged duration of hospitalization. Three patients were hospitalized for ALS-related complications, and one patient was hospitalized for respiratory distress when pneumoperitoneum developed after gastrostomy tube placement. Three of these patients died of complications attributable to ALS within 30 days of the procedure. Twenty-nine (32.6%) procedures required minimal sedation (e.g., bone marrow biopsy, cataract surgery) and were performed on an ambulatory basis. CONCLUSION: When caring for patients with ALS, the perioperative team must be prepared to treat potentially complex medical conditions that may not be directly related to the procedure and anesthetic management. However, minor procedures performed with minimal sedation may be safely performed on an ambulatory basis.

Occipital neuralgia associates with high cervical spinal cord lesions in idiopathic inflammatory demyelinating disease.

BACKGROUND: The association of trigeminal neuralgia with pontine lesions has been well documented in multiple sclerosis, and we tested the hypothesis that occipital neuralgia in multiple sclerosis is associated with high cervical spinal cord lesions. METHODS: We retrospectively reviewed the records of 29 patients diagnosed with both occipital neuralgia and demyelinating disease by a neurologist from January 2001 to December 2014. We collected data on demographics, clinical findings, presence of C2-3 demyelinating lesions, and treatment responses. RESULTS: The patients with both occipital neuralgia and multiple sclerosis were typically female (76%) and had a later onset (age > 40) of occipital neuralgia (72%). Eighteen patients (64%) had the presence of C2-3 lesions and the majority had unilateral symptoms (83%) or episodic pain (78%). All patients with documented sensory loss (3/3) had C2-3 lesions. Most patients with progressive multiple sclerosis (6/8) had C2-3 lesions. Of the eight patients with C2-3 lesions and imaging at onset of occipital neuralgia, five (62.5%) had evidence of active demyelination. None of the patients with progressive multiple sclerosis (3/3) responded to occipital nerve blocks or high dose intravenous steroids, whereas all of the other phenotypes with long term follow-up (eight patients) had good responses. CONCLUSIONS: A cervical spine MRI should be considered in all patients presenting with occipital neuralgia. In patients with multiple sclerosis, clinical features in occipital neuralgia that were predictive of the presence of a C2-3 lesion were unilateral episodic symptoms, sensory loss, later onset of occipital neuralgia, and progressive multiple sclerosis phenotype. Clinical phenotype predicted response to treatment.

Refractory Pain Management in Amyloid-Associated Peripheral Neuropathy.

OBJECTIVE: Systemic amyloidosis is a disease that often involves multiple organ systems, including the peripheral nervous system. Patients may present with severe, refractory neuropathic pain; however, the optimal treatment approach for pain for these patients remains unclear. CASE REPORT: A man with severe, refractory neuropathic pain in his bilateral upper and lower extremities and the trunk secondary to amyloid neuropathy is presented. Multiple medication trials, including neuropathic and opioid agents, produced considerable adverse effects and minimal relief. Scrambler therapy, a novel electrical stimulation modality, was used and was associated with substantial short-term but nonsustained benefit. Spinal cord stimulation was considered, but given his diffuse symptoms, it was deemed a less-than-optimal approach. Ultimately, an intrathecal drug delivery system was placed with infusion of hydromorphone, resulting in substantial pain reduction in all involved areas and with an improved adverse effect profile. This intervention resulted in immense improvement in the patient's quality of life, despite progression of his systemic amyloidosis. CONCLUSIONS: Severe pain in the setting of amyloid neuropathy is often difficult to treat. To our knowledge, this represents the first report of Scrambler therapy or an implanted intrathecal drug delivery system used for a patient with refractory amyloidosis-related neuropathic pain, resulting in substantial analgesic benefit and improved quality of life.

Outcomes of C1-2 joint injections.

OBJECTIVE: Intra-articular injections of the C1-2 joint are an effective therapeutic option for pain generated from degenerative and inflammatory conditions affecting the joint. Limited information exists about the adverse events (AEs) associated with these injections. The primary aim of this study is to describe the frequency and type of AEs associated with C1-2 joint injections. The secondary aim is to identify clinical factors associated with the occurrence of AEs of C1-2 joint injections. DESIGN/METHODS: A retrospective chart review was conducted on all C1-2 joint injections performed at the Mayo Pain Medicine Clinic in Rochester, MN, from January 1, 2005 through July 31, 2015. AE data were extracted from procedural and post-procedural clinical notes. Analysis was conducted to determine correlations between any AE and demographic and clinical characteristics. Using univariate and multivariate logistic regression analyses, associations were determined. RESULTS: From January 1, 2005 to July 31, 2015, 135 C1-2 injections were performed on 72 patients. Overall, at least 1 AE was reported in 18.5% of the injections. The most common AEs were post-procedural increase in pain and procedural vascular contrast uptake. There was a significant association between AE occurrence and greater pre-procedural maximum pain score. CONCLUSIONS: AEs from C1-2 joint injections occurred commonly, but there were no persistent or serious AEs associated with these injections. The data also demonstrate that patients with higher pre-procedural maximum pain scores are more likely to experience an AE.

Chronic inflammatory demyelinating polyradiculoneuropathy and anesthesia: a case series.

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an acquired autoimmune demyelinating polyneuropathy characterized by symmetrical diffuse weakness that also can rarely affect bulbar and respiratory muscles. The study objective was to describe perioperative outcomes of patients with CIDP who received general anesthesia. This retrospective observational study evaluated patients with active (diagnosed or treated within the previous year) CIDP who underwent general anesthesia at our institution between January 1, 2010, and December 31, 2015. Medical records were reviewed for perioperative outcomes with emphasis on respiratory complications or unexpected reactions to muscle relaxants. Seventeen patients with CIDP underwent general anesthesia, of whom 16 had muscle weakness. Succinylcholine was used in 5 cases (29.4%) and nondepolarizing muscle relaxants in 11 cases (64.7%). Two patients required postoperative mechanical ventilation; one was critically ill and the other had open heart surgery. One patient had aspiration on the second postoperative day and required endotracheal intubation and mechanical ventilation for 3 days. Three patients had worsening CIDP symptoms: 1 acutely after surgery; 1 several months later; and 1 who died in the hospital. The patient who died underwent lengthy abdominal exploration, had acute worsening of neurologic symptoms, and died after 46 days of malnutrition. Anesthetic concerns of patients with CIDP include frailty, bulbar dysfunction, and the effects of immunosuppressive therapy. Although our patients tolerated neuromuscular drugs, substantial theoretical concerns with these medications in patients with demyelinating neuropathies preclude safety in this population without further study.

Association of Long-term Opioid Therapy With Functional Status, Adverse Outcomes, and Mortality Among Patients With Polyneuropathy.

Importance: Polyneuropathy is one of the most common painful conditions managed within general and specialty clinics. Neuropathic pain frequently leads to decisions about using long-term opioid therapy. Understanding the association of long-term opioid use with functional status, adverse outcomes, and mortality among patients with polyneuropathy could influence disease-specific decisions about opioid treatment. Objectives: To quantify the prevalence of long-term opioid use among patients with polyneuropathy and to assess the association of long-term opioid use with functional status, adverse outcomes, and mortality. Design, Setting, and Participants: A retrospective population-based cohort study was conducted of prescriptions given to patients with polyneuropathy and to controls in ambulatory practice between January 1, 2006, and December 31, 2010, to determine exposure to long-term opioid use as well as other outcomes. The latest follow-up was conducted through November 25, 2016. Exposures: Long-term opioid therapy, defined by 1 or multiple consecutive opioid prescriptions resulting in 90 continuous days or more of opioid use. Main Outcomes and Measures: Prevalence of long-term opioid therapy among patients with polyneuropathy and controls. Patient-reported functional status, documented adverse outcomes, and mortality were compared between patients with polyneuropathy receiving long-term opioid therapy (≥90 days) and patients with polyneuropathy receiving shorter durations of opioid therapy. Results: Among the 2892 patients with polyneuropathy (1364 women and 1528 men; mean [SD] age, 67.5 [16.6] years) and the 14 435 controls (6827 women and 7608 men; mean [SD] age, 67.5 [16.5] years), patients with polyneuropathy received long-term opioids more often than did controls (545 [18.8%] vs 780 [5.4%]). Patients with polyneuropathy who were receiving long-term opioids had multiple functional status markers that were modestly poorer even after adjusting for medical comorbidity, including increased reliance on gait aids (adjusted odds ratio, 1.9; 95% CI, 1.4-2.6); no functional status markers were improved by long-term use of opioids. Adverse outcomes were more common among patients with polyneuropathy receiving long-term opioids, including depression (adjusted hazard ratio, 1.53; 95% CI, 1.29-1.82), opioid dependence (adjusted hazard ratio, 2.85; 95% CI, 1.54-5.47), and opioid overdose (adjusted hazard ratio, 5.12; 95% CI, 1.63-19.62). Conclusions and Relevance: Polyneuropathy increased the likelihood of long-term opioid therapy. Chronic pain itself cannot be ruled out as a source of worsened functional status among patients receiving long-term opioid therapy. However, long-term opioid therapy did not improve functional status but rather was associated with a higher risk of subsequent opioid dependency and overdose.

Erythromelalgia: Identification of a corticosteroid-responsive subset.

BACKGROUND: Corticosteroids (CS) may benefit certain patients with erythromelalgia. OBJECTIVES: Our objective was to determine clinical predictors of corticosteroid-responsive erythromelalgia. METHODS: Patients with erythromelalgia who received CS were identified and stratified into corticosteroid nonresponders (NRs), partial corticosteroid responders (PSRs), complete corticosteroid responders (CSRs), and steroid responders (SRs = PSRs + CSRs). In the study variable analysis, P < .05 was considered statistically significant. RESULTS: The median (interquartile range) age of the 31-patient cohort was 47 years (26-57 years), and 22 (71%) were female. Fourteen (45%) were NRs, 17 (55%) SRs, 8 (26%) PSRs, and 9 (29%) CSRs. A subacute temporal profile to disease zenith (<21 days) was described in 15 (48%) patients, of whom 13 (87%) were SRs (P = .003; odds ratio [OR] = 0.069 [95% confidence interval {CI}, 0.011-0.431]). Six (67%) CSRs reported a disease precipitant (eg, surgery, trauma, or infection; P = .007; OR = 12.667 [95% CI, 2-80.142]). SR patients received CS sooner than NR at 3 (3-12) versus 24 (17-45) months (P = .003). A high-dose CS trial (≥200 mg prednisone cumulatively) was administered to 17 (55%) patients, of whom 13 (76%) were SRs (P = .012; OR = 8.125 [95% CI, 1.612-40.752]). LIMITATIONS: This was a retrospective case series. CONCLUSION: An infectious, traumatic, or surgical precipitant and subacute presentation may portend CR erythromelalgia. A transient "golden window" where CS intervention is useful may exist before irreversible nociceptive remodeling and central sensitization occurs.