Clinical and Imaging Outcomes of Surgically Repaired Cerebrospinal Fluid-Venous Fistulas Identified by Lateral Decubitus Digital Subtraction Myelography.

OBJECTIVE: To describe clinical and radiographic outcomes of surgical repair of cerebrospinal fluid-venous fistula (CVF), an increasingly recognized cause of spontaneous intracranial hypotension that is poorly responsive to epidural blood patch (EBP). METHODS: Retrospective review identified adult patients who had lateral decubitus digital subtraction myelography indicative of cerebrospinal fluid leak at Mayo Clinic between November 2018 and February 2020, with clearly localized CVF, followed by surgical treatment. Patients without available imaging before or after surgery were excluded. History of EBP and clinical response to EBP were evaluated along with surgical outcomes. RESULTS: Of 25 patients with CVF who met protocol criteria and were included in the data analysis, 22 (88%) received EBP, but clinical benefit lasting ≥4 weeks occurred in only 2 of 22 (9%). Headache was the most prominent preoperative feature among patients (24/25; 96%). Following surgery, 18 of 24 (75%) patients had complete headache improvement, 4 (17%) had partial improvement, and 2 (8%) had no improvement. Ten of 25 (40%) patients reported cognitive disturbance at baseline; at follow-up, 5 of 10 (50%) had complete improvement, 3 (30%) had partial improvement, and 2 (20%) had no improvement. On postoperative brain magnetic resonance imaging, 6 of 25 (24%) patients had complete resolution of findings by Bern score criteria, 18 (72%) showed partial improvement, and 1 (4%) patient showed no improvement. Adverse events were minor and included surgical site pain and paresthesias. CONCLUSIONS: Surgical repair of CVF resulted in improvements in headache and other symptoms, with few side effects.

Long term outcomes of occipital nerve stimulation.

Background: Occipital nerve stimulation (ONS) has been investigated as a potential treatment for disabling headaches and has shown promise for disorders such as chronic migraine and cluster headache. Long term outcomes stratified by headache subtype have had limited exploration, and literature on outcomes of this neuromodulatory intervention spanning 2 or more years is scarce. Measures: We performed a narrative review on long term outcomes with ONS for treatment of headache disorders. We surveyed the available literature for studies that have outcomes for 24 months or greater to see if there is a habituation in response over time. Review of the literature revealed evidence in treatment of occipital neuralgia, chronic migraine, cluster headache, cervicogenic headache, short lasting unilateral neuralgiform headache attacks (SUNHA) and paroxysmal hemicrania. While the term "response" varied per individual study, a total of 17 studies showed outcomes in ONS with long term sustained responses (as defined per this review) in the majority of patients with specific headache types 177/311 (56%). Only 7 studies in total (3 cluster, 1 occipital neuralgia, 1 cervicogenic headache, 1 SUNHA, 1 paroxysmal hemicrania) provided both short-term and long-term responses up to 24 months to ONS. In cluster headache, the majority of patients (64%) were long term responders (as defined per this review) and only a minority of patients 12/62 (19%) had loss of efficacy (e.g., habituation). There was a high number 313/439 (71%) of adverse events per total number of patients in the studies including lead migration, requirements of revision surgery, allergy to surgical materials, infection and intolerable paresthesias. Conclusions: With the evidence available, the response to ONS was sustained in the majority of patients with cluster headache with low rates of loss of efficacy in this patient population. There was a high percent of adverse events per number of patients in long term follow-up and likely related to the off-label use of leads typically used for spinal cord stimulation. Further longitudinal assessments of outcomes in occipital nerve stimulation with devices labelled for use in peripheral nerve stimulation are needed to evaluate the extent of habituation to treatment in headache.

Great Auricular Neuralgia: Case Series.

BACKGROUND/OBJECTIVE: The great auricular nerve (GAN) arises from C2-C3 and provides innervation over the skin in the pre-auricular region, jaw angle, posteroinferior pinna, and mastoid. Although damage to the GAN has been reported following trauma or procedures nearby this nerve course, neuralgia of this nerve is uncommon with knowledge based on a handful of case reports in literature. The objective of this study is to describe the presentation, treatment, and outcome of 13 cases of GAN neuralgia. METHODS: Case series. Retrospecive review of charts from 1994 to 2018 with diagnoses: "auricular neuralgia," "auricular neuritis," or "auricular neuropathy." We included subjects with neuralgic pain within the distribution of the GAN, and excluded patients with atypical facial pain, GAN neuropathy, or unclear etiology. RESULTS: Of 79 charts, 13 patients met criteria (age at onset 11-59; 11 women, 2 men). Pain was most often described as paroxysmal stabbing provoked by: turning the head (n = 7), touching the neck (n = 5), neck position during sleep (n = 2), jaw movement (n = 2), and other (n = 2). Seven patients received GAN blocks: all noted dramatic improvement in pain, including 3 who continued to receive serial blocks at our institution successfully for the next 2 to 5 years. Two patients successfully transitioned from GAN blocks to GAN stimulators. One patient with GAN lymphoma had resolution of pain following GAN resection. CONCLUSION: GAN neuralgia should be considered in the differential for periauricular pain. GAN blocks or stimulators may be helpful for pain management.

Spinal cord injury from fluoroscopically guided intercostal blocks with phenol.

BACKGROUND: Image guided intercostal blocks are commonly performed and considered relatively safe. Chemical denervation is commonly used in clinical practice for treatment of chronic non-cancer associated pain. OBJECTIVE: To report a case of spinal cord injury resulting from fluoroscopically guided intercostal blocks with phenol. STUDY DESIGN: Case report. SETTING: Inpatient hospital service. RESULTS/CASE REPORTS: A 53 year-old women was transferred from her local facility for acute onset of lower extremity paresis beginning shortly after right intercostal nerve injections of 2 mL of preservative-free phenol at the T7, 8, 9 levels. She had previous intercostal blocks for chronic right-sided mid thoracic/abdominal pain every 3 months for at least one year without sequelae. Within 20 minutes of the injection, she developed a sensation of right leg weakness and heaviness. Over several hours she developed worsening right leg weakness, and then left leg weakness, followed by urinary retention. Admission examination revealed severe right greater than left leg weakness, right lower extremity hyperesthesia to T10, absent lower extremity reflexes, and bilateral extensor plantar responses. Magnetic resonance imaging (MRI) of the entire spine demonstrated extensive T2/DWI hyperintensity in the central spinal cord from T1 to L1 with mild cord enlargement and enhancement at T7-9 (sites of injection). Extensive serum and cerebrospinal fluid (CSF) evaluation did not show any evidence of an infectious, inflammatory, or metabolic cause to her myelopathy. Repeat MRI of the entire spine demonstrated near complete resolution of the T2 signal abnormality. One month after presentation, despite radiographic improvement, the patient showed some clinical improvement, but remained walker dependent and with neurogenic bowel and bladder. LIMITATIONS: This report describes a single case report. CONCLUSION: This case offers several lessons for a pain specialist including 1) the potential for a neurologic catastrophe (spinal cord injury) from aqueous neurolytic intercostal blocks despite "safe" contrast spread; 2) potential mechanisms of neurogenic injury with intercostal blocks; 3) review of modifiable factors to decrease the risk of neurogenic injury; and 4) review of potential interventions (steroids, lumbar drain) to improve outcome in the setting of iatrogenic procedural related spinal cord injury.