Kissoon, Narayan

Introduction Spontaneous intracranial hypotension (SIH) caused by a spinal cerebrospinal fluid (CSF) leak classically presents with orthostatic headache. Digital subtraction myelography (DSM) has a well-established diagnostic yield in the absence of extradural spinal collection. At our institution, DSM is followed by lateral decubitus CT myelogram (LDCTM) in the same decubitus position to increase diagnostic yield of the combined study. We evaluated the incremental diagnostic yield of LDCTM following negative DSM and reviewed patient outcomes. Methods Retrospective review of consecutive DSMs with subsequent LDCTM from April 2019 to March 2021 was performed. Combined reports were reviewed, and studies with positive DSMs were excluded. Of the exams with negative DSM, only studies with LDCTM reports identifying potential leak site were included. Interventions and follow-up clinical notes were reviewed to assess symptoms improvement following treatment. Results Of the 83 patients with negative DSMs, 11 (13.2%) had positive leak findings on LDCTMs, and 21 (25.3%) were equivocal. Of 11 positive LDCTMs, 6 leaks were nerve sheath tears (NSTs) and 5 were CSF-venous fistulas (CVFs). 10/11 (90.9%) had intervention and follow-up, with 9/10 (90%) having positive clinical outcome. Of the 21 equivocal LDCTM patients (19 CVFs and 2 NSTs), 15 (71.4%) had interventions and follow-up, with 3/15 (20.0%) with positive clinical outcomes. Conclusion LDCTM following negative DSM has an incremental diagnostic yield up to 38.6%, with up to 14.5% of positive patient outcomes following treatment. LDCTM should be considered after DSM to maximize diagnostic yield of the combined exam.

Abstract Objective To provide an overview of the current available literature on peripheral nerve blocks for the management of migraine and other headache disorders in adults. Background Peripheral nerve blocks have been commonly performed in the headache practice for migraine, cluster headache, occipital neuralgia, and other headache disorders, despite a paucity of evidence supporting their use historically. In the past decade, there has been an effort to explore the efficacy and safety of peripheral nerve blocks for the management of headache, with the greatest interest centered around greater occipital blocks. Design We performed a search in PubMed using key words including “occipital nerve blocks,” “peripheral nerve blocks,” “occipital nerve,” “migraine,” “cluster headache,” and “neuralgia.” We reviewed the randomized controlled trials (RCTs), observational studies, and case series, and summarized the anatomy, techniques, and the evidence for the use of peripheral nerve blocks in different headache disorders, with particular focus on available RCTs. Case reports were included for a detail review of adverse events. Results Of 12 RCTs examining the use of greater occipital nerve blocks for migraine, all but one demonstrate efficacy with reduction in headache frequency, intensity, and/or duration compared to placebo. Studies have not demonstrated a difference in clinical outcomes with the use of corticosteroids for nerve blocks compared to blocks with local anesthetic in the treatment of migraine. There are two RCTs supporting the use of greater occipital blockade for cluster headache, both showing benefit of suboccipitally injected corticosteroid. One RCT suggests benefit of greater occipital nerve blocks for cervicogenic headache. Observational studies and case series/reports show that greater occipital nerve block may be effective in prolonged migraine aura, status migrainosus, post‐dural puncture headache, and occipital neuralgia. Overall, peripheral nerve blocks are well tolerated. Serious side effects are rare but have been reported, including acute cerebellar syndrome and infection. Conclusions Peripheral nerve blocks, especially occipital nerve blocks, are a viable treatment option for migraine and may be helpful in cluster headache as a transitional therapy or rescue therapy. Additional prospective studies are needed to investigate the efficacy and safety of occipital nerve blocks for long‐term migraine prevention, as well as for other headache disorders, such as occipital neuralgia.

Summary The COVID‐19 pandemic transformed everyday life, but the implications were most impactful for vulnerable populations, including patients with chronic pain. Moreover, persistent pain is increasingly recognised as a key manifestation of long COVID. This narrative review explores the consequences of the COVID‐19 pandemic for chronic pain. Publications were identified related to the COVID‐19 pandemic influence on the burden of chronic pain, development of new‐onset pain because of long COVID with proposed mechanisms and COVID‐19 vaccines and pain interventions. Broadly, mechanisms underlying pain due to SARS‐CoV‐2 infection could be caused by ‘systemic inflammatory‐immune mechanisms’, ‘direct neuropathic mechanisms’ or ‘secondary mechanisms due to the viral infection or treatment’. Existing chronic pain populations were variably impacted and social determinants of health appeared to influence the degree of effect. SARS‐CoV‐2 infection increased the absolute numbers of patients with pain and headache. In the acute phase, headache as a presenting symptom predicted a milder course. New‐onset chronic pain was reportedly common and likely involves multiple mechanisms; however, its prevalence decreases over time and symptoms appear to fluctuate. Patients requiring intensive support were particularly susceptible to long COVID symptoms. Some evidence suggests steroid exposure (often used for pain interventions) may affect vaccine efficacy, but there is no evidence of clinical repercussions to date. Although existing chronic pain management could help with symptomatic relief, there is a need to advance research focusing on mechanism‐based treatments within the domain of multidisciplinary care.

Background and Purpose: Strict maintenance of normovolemia is standard of care in treatment of aneurysmal subarachnoid hemorrhage (aSAH) and induced hypervolemia is used to treat delayed cerebral ischemia (DCI) from vasospasm. Fluid-related complications are not uncommon. We tested the hypothesis that fluid balance affected clinical outcomes in aSAH. Methods: We reviewed 307 patients with aSAH admitted to the Neuroscience Intensive Care Unit (NICU) from October 2001 to June 2011. We collected data on fluid balance during NICU stay, clinical and radiographic evidence of vasospasm, cardiopulmonary complications, and functional outcomes by modified Rankin scale (mRS) upon follow-up (mean 8 ± 8 months). Poor functional outcome was defined as mRS 3-6. Associations of variables of interest with outcome were assessed using univariable and multivariable logistic regression. Propensity scores were estimated to account for imbalances between patients with positive versus negative fluid balance and were included in multivariable models. Results: Average net fluid balance was 1153 ± 5586 mL. Results of univariate analysis are shown on the Table. On multivariate analysis, WFNS grade at nadir (p<0.001, OR=3.09, 95%CI 2.38-4.02) and positive fluid balance per liter increase (p=0.0005, OR=1.12, 95%CI 1.05-1.20) were associated with poor functional outcome. For every liter increase in positive net fluid balance, there was a 12% increased risk of a poor functional outcome on adjusted analysis (Area under ROC Curve 0.868). The association between positive net fluid balance and poor functional outcomes was confirmed using propensity score analysis to control for multiple confounding variables. Conclusions: Greater positive net fluid balance is independently associated with poorer functional outcome in patients with aSAH. This association does not appear to be solely explained by an excess of cardiopulmonary complications.

Background and purpose Cerebral venous sinus thrombosis (CVST) is a rare condition but an important complication of spontaneous intracranial hypotension (SIH). We reviewed our experience of patients with SIH and assessed for the presence of CVST. Methods We reviewed the medical records and imaging studies from our tertiary referral institution, assessing patients with clinically suspected SIH as well as imaging findings of intracranial hypotension. All relevant brain MRIs were reviewed for the presence of brain sag, pachymeningeal enhancement, and CVST. Results Among 563 patients with a clinical diagnosis of SIH, 431 (76%) demonstrated brain sag. In the overall patient cohort, a total of 5 patients had CVST (0.9%) and all 5 of these patients demonstrated findings of brain sag. Of the patients with CVST, 3 had significant complications, including dural arteriovenous fistulas (2 patients) and lobar hemorrhage with seizure (1 patient). Conclusion SIH is a risk factor for the development of CVST. In our review of 563 patients with clinical and/or imaging findings of SIH, 0.9% of patients were diagnosed with CVST and 3 of these patients (60%) had additional severe complications.

AbstractLow back pain and neck pain, often with associated radiculopathy, are two of the most common reasons for referral to the outpatient neurology clinic. A thorough clinical evaluation remains paramount in establishing an accurate diagnosis and subsequently an appropriate treatment plan. In this article, we review anatomic considerations for spondylotic radiculopathy; outline the clinical approach for the evaluation of these patients, including discussion of electrodiagnostic and imaging modalities; and address treatment options based on a stratified treatment approach.

Background The past two decades have witnessed a surge in the use of cervical spine joint procedures including joint injections, nerve blocks and radiofrequency ablation to treat chronic neck pain, yet many aspects of the procedures remain controversial. Methods In August 2020, the American Society of Regional Anesthesia and Pain Medicine and the American Academy of Pain Medicine approved and charged the Cervical Joint Working Group to develop neck pain guidelines. Eighteen stakeholder societies were identified, and formal request-for-participation and member nomination letters were sent to those organizations. Participating entities selected panel members and an ad hoc steering committee selected preliminary questions, which were then revised by the full committee. Each question was assigned to a module composed of 4–5 members, who worked with the Subcommittee Lead and the Committee Chairs on preliminary versions, which were sent to the full committee after revisions. We used a modified Delphi method whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chairs, who incorporated the comments and sent out revised versions until consensus was reached. Before commencing, it was agreed that a recommendation would be noted with >50% agreement among committee members, but a consensus recommendation would require ≥75% agreement. Results Twenty questions were selected, with 100% consensus achieved in committee on 17 topics. Among participating organizations, 14 of 15 that voted approved or supported the guidelines en bloc, with 14 questions being approved with no dissensions or abstentions. Specific questions addressed included the value of clinical presentation and imaging in selecting patients for procedures, whether conservative treatment should be used before injections, whether imaging is necessary for blocks, diagnostic and prognostic value of medial branch blocks and intra-articular joint injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for designating a block as positive, how many blocks should be performed before radiofrequency ablation, the orientation of electrodes, whether larger lesions translate into higher success rates, whether stimulation should be used before radiofrequency ablation, how best to mitigate complication risks, if different standards should be applied to clinical practice and trials, and the indications for repeating radiofrequency ablation. Conclusions Cervical medial branch radiofrequency ablation may provide benefit to well-selected individuals, with medial branch blocks being more predictive than intra-articular injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of false-negatives (ie, lower overall success rate). Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

Abstract Background The past two decades have witnessed a surge in the use of cervical spine joint procedures including joint injections, nerve blocks and radiofrequency ablation to treat chronic neck pain, yet many aspects of the procedures remain controversial. Methods In August 2020, the American Society of Regional Anesthesia and Pain Medicine and the American Academy of Pain Medicine approved and charged the Cervical Joint Working Group to develop neck pain guidelines. Eighteen stakeholder societies were identified, and formal request-for-participation and member nomination letters were sent to those organizations. Participating entities selected panel members and an ad hoc steering committee selected preliminary questions, which were then revised by the full committee. Each question was assigned to a module composed of 4–5 members, who worked with the Subcommittee Lead and the Committee Chairs on preliminary versions, which were sent to the full committee after revisions. We used a modified Delphi method whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chairs, who incorporated the comments and sent out revised versions until consensus was reached. Before commencing, it was agreed that a recommendation would be noted with &gt;50% agreement among committee members, but a consensus recommendation would require ≥75% agreement. Results Twenty questions were selected, with 100% consensus achieved in committee on 17 topics. Among participating organizations, 14 of 15 that voted approved or supported the guidelines en bloc, with 14 questions being approved with no dissensions or abstentions. Specific questions addressed included the value of clinical presentation and imaging in selecting patients for procedures, whether conservative treatment should be used before injections, whether imaging is necessary for blocks, diagnostic and prognostic value of medial branch blocks and intra-articular joint injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for designating a block as positive, how many blocks should be performed before radiofrequency ablation, the orientation of electrodes, whether larger lesions translate into higher success rates, whether stimulation should be used before radiofrequency ablation, how best to mitigate complication risks, if different standards should be applied to clinical practice and trials, and the indications for repeating radiofrequency ablation. Conclusions Cervical medial branch radiofrequency ablation may provide benefit to well-selected individuals, with medial branch blocks being more predictive than intra-articular injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of false-negatives (ie, lower overall success rate). Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

AbstractObjectiveTo systematically evaluate the efficacy and effectiveness of percutaneous interventional treatments for prevention of migraine through a qualitative and (when possible) quantitative analysis.MethodsAn expert panel was asked to develop recommendations for the multidisciplinary preventive treatment of migraine, including interventional strategies. The committee conducted a systematic review and (when evidence was sufficient) a meta-analytic review by using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) criteria and the modified Cochrane Risk of Bias analysis available in the Covidence data management program. Clinical questions addressed adults with migraine who should be offered prevention. Examined outcomes included headache days, acute medication use, and functional impairment. Acute management of migraine was outside the scope of this guideline.ResultsThe committee screened 1,195 studies and assessed 352 by full text, yielding 16 randomized controlled trials that met the inclusion criteria.Recommendations and ConclusionsAs informed by evidence related to the preselected outcomes, adverse event profile, cost, and values and preferences of patients, onabotulinumtoxinA received a strong recommendation for its use for chronic migraine prevention and a weak recommendation against its use for episodic migraine prevention. Greater occipital nerve blocks received a weak recommendation for their use for chronic migraine prevention. For greater occipital nerve block, steroid received a weak recommendation against its use vs the use of local anesthetic alone. Occipital nerve with supraorbital nerve blocks, sphenopalatine ganglion blocks, cervical spine percutaneous interventions, and implantable stimulation all received weak recommendations for their use for chronic migraine prevention. The committee found insufficient evidence to assess trigger point injections in migraine prevention and highly discouraged the use of intrathecal medication.