A Plant-Based Dietary Intervention for Preoperative Glucose Optimization in Diabetic Patients Undergoing Total Joint Arthroplasty.

Purpose. The purpose of this study was to assess the feasibility and effectiveness of a whole food plant-based diet (WFPBD) to improve day of surgery fasting blood glucose (FBG) among patients with type 2 diabetes (T2D). Patients and Methods. Ten patients with T2D scheduled for a total hip or total knee replacement were recruited. For 3 weeks preceding their surgeries, subjects were asked to consume an entirely WFPBD. Frozen WFPBD meals were professionally prepared and delivered to each participant for the 3 weeks prior to surgery. FBG was reassessed on the morning of surgery and compared with preintervention values. Compliance with the diet was assessed. Results. Mean age of subjects and reported duration of diabetes was 65 and 8 years, respectively, average hemoglobin A1c (HbA1c) was 6.6%, and 6 were women. Mean FBG decreased from 127 to 116 mg/dL (P = .2). Five of the subjects experienced improvement in glycemic control, with an average decline of 11 mg/dL. Conclusion. A WFPBD is a potentially effective intervention to improve glycemic control among patients with T2D during the period leading up to surgery. Future controlled trials on a larger sample of patients to assess the impact of a WFPBD on glycemic control and surgical outcomes are warranted.

Tongue Tied after Shoulder Surgery: A Case Series and Literature Review.

This article presents three cases of cranial nerve palsy following shoulder surgery with general anesthesia in the beach chair position. All patients underwent preoperative ultrasound-guided interscalene nerve block. Two cases of postoperative hypoglossal and one case of combined hypoglossal and recurrent laryngeal nerve palsies (Tapia's syndrome) were identified. Through this case series, we provide a literature review identifying postoperative cranial nerve palsies in addition to the discussion of possible etiologies. We suggest that intraoperative patient positioning and/or airway instrumentation is most likely causative. We conclude that the beach chair position is a risk factor for postoperative hypoglossal nerve palsy and Tapia's syndrome.

The effect of ampule size of fentanyl on perioperative intravenous opioid dosing.

BACKGROUND AND AIMS: There are limited data on the effect of ampule size on drug dosing. The objective of this study is to determine the effect of ampule size on perioperative opioid dosing and post-anesthesia care unit (PACU) outcomes. MATERIAL AND METHODS: This was a retrospective review of patients undergoing robotically assisted laparoscopic radical prostatectomy before and after a 5-ml fentanyl ampule was discontinued. The primary outcome was intraoperative opioid administration divided into fentanyl at induction of anesthesia, total fentanyl, and total opioid. Secondary outcomes observed in PACU included the opioid administered, visual analog scale (VAS) pain scores, postoperative nausea and vomiting, and length of stay in PACU. RESULTS: A total of 100 patients (50 PRE and 50 POST) were included. In the intraoperative opioid administration, mean (SD) of fentanyl at induction was 117.0 (49.3) in PRE group and 85.0 (35.4) µg in POST group (P < 0.01). The total fentanyl requirement was 247.0 (31.0) in PRE group and 158.5 (85.1) µg in POST group (P < 0.01). The total opioid in intravenous morphine equivalents (IVME) was 34.1 (5.8) in PRE group and 23.2 (6.8) mg in POST group (P < 0.01). Among the secondary outcomes, mean (SD) of IVME of opioid was 7.7 (8.2) in PRE group and 9.9 (8.1) mg in POST group (P = 0.18). The VAS pain score on arrival was 0.7 (1.4) in PRE group and 3.8 (3.3) in POST group (P < 0.01). The cumulative VAS pain score was 2.3 (2.0) in PRE group and 3.3 (2.2) in POST group (P < 0.01). The length of stay was significantly more in POST group, 193.8 (75.8) minutes, as compared with PRE group, 138.6 (61.0) minutes (P < 0.01). CONCLUSIONS: A change in the ampule size significantly affected intraoperative dosing, PACU pain scores, and PACU length of stay in patients undergoing robotically assisted laparoscopic radical prostatectomy under general anesthesia. This was explained by clinician's desire to conserve the drug and avoid the complex process of narcotic waste disposal.

Pharmacologic Considerations for Pediatric Sedation and Anesthesia Outside the Operating Room: A Review for Anesthesia and Non-Anesthesia Providers.

Understanding the pharmacologic options for pediatric sedation outside the operating room will allow practitioners to formulate an ideal anesthetic plan, allaying anxiety and achieving optimal immobilization while ensuring rapid and efficient recovery. The authors identified relevant medical literature by searching PubMed, MEDLINE, Embase, Scopus, Web of Science, and Google Scholar databases for English language publications covering a period from 1984 to 2017. Search terms included pediatric anesthesia, pediatric sedation, non-operating room sedation, sedation safety, and pharmacology. As a narrative review of common sedation/anesthesia options, the authors elected to focus on studies, reviews, and case reports that show clinical relevance to modern day sedation/anesthesia practice. A variety of pharmacologic agents are available for sedation/anesthesia in pediatrics, including midazolam, fentanyl, ketamine, dexmedetomidine, etomidate, and propofol. Dosing ranges reported are a combination of what is discussed in the reviewed literature and text books along with personal recommendations based on our own practice. Several reports reveal that ketofol (a combination of ketamine and propofol) is quite popular for short, painful procedures. Fospropofol is a newer-generation propofol that may confer advantages over regular propofol. Remimazolam combines the pharmacologic effects of remifentanil and midazolam. A variety of etomidate derivatives such as methoxycarbonyl-etomidate, carboetomidate, methoxycarbonyl-carboetomidate, and cyclopropyl-methoxycarbonyl metomidate are in development stages. The use of nitrous oxide as a mild sedative, analgesic, and amnestic agent is gaining popularity, especially in the ambulatory setting. Utilizing a dedicated and experienced team to provide sedation enhances safety. Furthermore, limiting sedation plans to single-agent pharmacy appears to be safer than using multi-agent plans.

Peroral endoscopic myotomy: procedural complications and pain management for the perioperative clinician.

Achalasia refers to the lack of smooth muscle relaxation of the distal esophagus. Although nonsurgical treatments such as pneumatic dilatation of the distal esophagus and botulinum toxin injections have been performed, these procedures have limited duration. Similarly, surgical treatment with Heller myotomy is associated with complications. At our institution, we perform the peroral endoscopic myotomy (POEM) in qualified patients. Briefly, POEM involves endoscopic creation of a mid-esophageal submucosal bleb, creation of a submucosal tunnel with the endoscope, and then a distal myotomy, resulting in relaxation of the distal esophagus. The aim of our study is to document perioperative pain and associated pain management for our initial patients undergoing POEM and to review the literature for perioperative complications of this procedure. Therefore, anesthetic and pain management for our initial eleven patients undergoing POEM were reviewed. Patient demographics, pre-POEM pain medication history, perioperative pain medication requirements, and post-POEM pain scores were examined. We found post-POEM pain was usually in the mild-moderate range; a combination of medications was effective (opioids, nonsteroidal anti-inflammatory drugs, acetaminophen). Our literature search revealed a wide frequency range of complications such as pneumoperitoneum and subcutaneous emphysema, with rare serious events such as capnopericardium leading to cardiac arrest. In conclusion, our experience with POEM suggests pain and can be managed adequately with a combination of medications; the procedure appears to be safe and reasonable to perform in an outpatient endoscopy unit.

Insertion of intra-oral electrodes for cranial nerve monitoring using a Crowe-Davis retractor.

Acoustic neuroma resection is an example of a neurosurgical procedure where the brainstem and multiple cranial nerves are at risk for injury. Electrode placement for monitoring of the glossopharyngeal and hypoglossal nerves during acoustic neuroma resection can be challenging. The purpose of this report is to illustrate the use of a device for intra-oral electrode placement for intraoperative monitoring of the glossopharyngeal and hypoglossal nerves. A 60-year-old male presented for acoustic neuroma resection. Under general anesthesia, a Crowe-Davis retractor was used to open the mouth, providing access to the posterior pharynx. For glossopharyngeal monitoring, two bent subdermal needle electrodes were inserted just lateral to the uvula. Two additional electrodes were inserted on the lateral tongue to monitor the hypoglossal nerve. Cranial nerves monitoring was conducted utilizing both free running and triggered electromyography of the trigeminal and facial nerves in addition to the lower cranial nerves. The tumor was resected successfully. Monitoring of the cranial nerves (including the glossopharyngeal and hypoglossal nerves) revealed no concerning responses. The Crowe-Davis retractor and the technique described allowed insertion of electrodes for neural monitoring, contributing to neural preservation.

Survey of pain specialists regarding conversion of high-dose intravenous to neuraxial opioids.

The conversion of high-dose intravenous (IV) opioids to an equianalgesic epidural (EP) or intrathecal (IT) dose is a common clinical dilemma for which there is little evidence to guide practice. Expert opinion varies, though a 100 IV:10:EP:1 IT conversion ratio is commonly cited in the literature, especially for morphine. In this study, the authors surveyed 724 pain specialists to elucidate the ratios that respondents apply to convert high-dose IV morphine, hydromorphone, and fentanyl to both EP and IT routes. Eighty-three respondents completed the survey. Conversion ratios were calculated and entered into graphical scatter plots. The data suggest that there is wide variation in how pain specialists convert high-dose IV opioids to EP and IT routes. The 100 IV:10 EP:1 IT ratio was the most common answer of survey respondent, especially for morphine, though also for hydromorphone and fentanyl. Furthermore, more respondents applied a more aggressive conversion strategy for hydromorphone and fentanyl, likely reflecting less spinal selectivity of those opioids compared with morphine. The authors conclude that there is little consensus on this issue and suggest that in the absence of better data, a conservative approach to opioid conversion between IV and neuraxial routes is warranted.

Angioedema: Classification, management and emerging therapies for the perioperative physician.

Angioedema is a rare condition which manifests as sudden localised, non-pitting swelling of certain body parts including skin and mucous membranes. It is vital that anaesthesiologists understand this condition, as it may present suddenly in the perioperative period with airway compromise. To identify literature for this review, the authors searched the PubMed, Medline, Embase, Scopus and Web of Science databases for English language articles covering a 10-year period, 2006 through 2016. Angioedema can be either mast-cell mediated or bradykinin-induced. Older therapies for histaminergic symptoms are well known to anaesthesiologists (e.g., adrenaline, anti-histamines and steroids), whereas older therapies for bradykinin-induced symptoms include plasma and attenuated androgens. New classes of drugs for bradykinin-induced symptoms are now available, including anti-bradykinin, plasma kallikrein inhibitor and C1 esterase inhibitors. These can be used prophylactically or as rescue medications. Anaesthesiologists are in a unique position to coordinate perioperative care for this complex group of patients.

Current and emerging treatments for hypercholesterolemia: A focus on statins and proprotein convertase subtilisin/kexin Type 9 inhibitors for perioperative clinicians.

Statins are a mainstay of hyperlipidemia treatment. These drugs inhibit the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase and have beneficial effects on atherosclerosis including plaque stabilization, reduction of platelet activation, and reduction of plaque proliferation and inflammation. Statins also have a benefit beyond atherosclerotic plaque, including anticoagulation, vasodilatation, antioxidant effects, and reduction of mediators of inflammation. In the perioperative period, statins appear to contribute to improved outcomes via these mechanisms. Both vascular and nonvascular surgery patients have been shown in prospective studies to have lower risk of adverse cardiac outcomes when initiated on statins preoperatively. However, not all patients can tolerate statins; the search for novel lipid-lowering therapies led to the discovery of the proprotein convertase subtilisin/kexin Type 9 (PCSK9) inhibitors. These drugs are fully-humanized, injectable monoclonal antibodies. With lower PCSK9 activity, low-density lipoprotein cholesterol (LDL-C) receptors are more likely to be recycled to the hepatocyte surface, where they serve to clear plasma LDL-C. Evidence from several prospective studies shows that these new agents can significantly lower LDL-C levels. While PCSK9 inhibitors offer hope of effective therapy for patients with familial hyperlipidemia or intolerance of statins, several important questions remain, including the results of long term cardiovascular outcome studies. The perioperative effects of new LDL-C-lowering drugs are unknown at present but are likely to be similar to the older agents.

Findings of a Naloxone Database and its Utilization to Improve Safety and Education in a Tertiary Care Medical Center.

INTRODUCTION: Analyzing hospital naloxone use may assist in identification of areas for quality and safety improvement. Our primary objective is to quantitate the incidence of hospital naloxone use and to assess certain patient populations at risk. METHODS: During the years 2008 to 2011, each clinical scenario where naloxone was administered on an in-patient care ward was reviewed. The events were assessed to separate situations where naloxone rescue was effective in reversing opioid-induced intoxication vs. others. Further analysis was conducted to stratify patient populations at greatest risk. RESULTS: Naloxone was administered for well-defined opioid-induced respiratory depression and oversedation 61% of the time, the remainder used for patient deterioration of other etiology. Surgical populations are at risk with an incidence of 3.8/1,000 hospitalized patients, and this is the greatest within 24 hours of surgery. General surgical patients represent the highest surgical patient risk at 5.5/1,000. Medical patients represent lower risk at 2.0/1,000. Patients with patient-controlled analgesia and epidural opioid infusion are high risk at 12.1 and 13.1/1,000 patients, respectively. Many quality and safety interventions were gradually implemented in response to this data and are summarized. These include nursing and provider education, electronic medical record modification, and more stringent patient monitoring practices. CONCLUSION: Examination of naloxone use can assist in the identification and stratification of patients at risk for opioid-induced respiratory depression and oversedation and can serve as a driver for improvements in hospital patient safety. This information can also guide other institutions interested in similar improvements.

Use of botulinum toxin injections to treat peripheral stimulator induced facial muscle twitching: a case report.

BACKGROUND: Facial pain can be a management challenge. Peripheral nerve/field stimulation may be an effective option for refractory cases, but direct muscle stimulation with facial twitching may result. Botulinum toxin injections have been used for blepharospasm and may be effective when facial stimulation results in unacceptable facial muscle twitching due to peripheral stimulation. CASE PRESENTATION: A 53-year old female suffered with chronic, refractory facial pain and migraines. Her facial pain began after a root canal of a left upper molar. She was trialed and then permanently implanted with a 1 × 8 sub-compact percutaneous stimulator lead, resulting in improved pain control and reduced medication use. However, she experienced blepharospasm whenever the amplitude was above 2.75 A. Therefore, she was treated with botulinum toxin injections into her bilateral cheek, face, temple and occiput. This treatment provided excellent relief of the facial spasms, allowing her to use her stimulator at high amplitudes, and thereby maximizing her pain relief. She received two subsequent treatments of botulinum toxin injections at 5-month intervals with similar results. CONCLUSION: Peripheral nerve/field stimulation is being used for headaches and facial pain. An undesirable side effect of this emerging therapy is direct muscle stimulation. Botulinum toxin injections may be an effective treatment modality when stimulation techniques provide pain relief but also causes muscle twitching.

Patient understanding of the importance of statin use in the perioperative period.

OBJECTIVE: Perioperative hydroxy-3-methyl glutaryl coenzyme A reductase inhibitors (statins) have been shown to decrease morbidity and mortality after noncardiac surgery. The objective of this study was to assess patient understanding of the potential benefits of perioperative statins in a select population already on chronic therapy. A secondary aim was to determine the frequency with which patients recalled having a discussion with their provider regarding perioperative statins. DESIGN: Survey. SETTING: Teaching hospital. PARTICIPANTS: Patients taking daily statins presenting to a preoperative medical evaluation clinic were offered a 12-question survey that assessed their understanding of the potential benefit of taking the medication in the perioperative period. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: One hundred thirty-two patients completed the questionnaire. The mean age was 68.3 years (standard deviation, 9.0); 42% were female. The most frequent surgical referral to the clinic was orthopedics, at 36%. The most common statin prescribed was atorvastatin, in 35% of patients. Twenty-seven percent of patients (n = 36) recognized that perioperative statins are beneficial; 44% of these patients (n = 14) cited decreased cholesterol during the procedure as the reason, representing 12% of the total sampled population. Twenty-two percent (n = 8) of those recognizing the benefit of perioperative statins identified a decrease in the risk of heart attack or death as the reason. This represented only 6% of the total sample. One percent of surgeons mentioned statins in relation to the planned surgery; 2% of primary or prescribing physicians mentioned the medication in relation to surgery. CONCLUSIONS: This study suggested low patient understanding of the potential importance and reasons for perioperative statins. In addition, this study also suggested that the information regarding the importance of perioperative statins is not being relayed to the patient at the level of the surgeon or primary care physician. All physicians involved in perioperative care can offer improved patient education to promote compliance with statin therapy in hopes of a favorable impact on perioperative outcomes.

Analysis of adverse events in the management of chronic migraine by peripheral nerve stimulation.

OBJECTIVE: In this study, we analyze device- and procedure-related adverse events (AEs) from a recent prospective, multicenter, double-blinded controlled study that utilized peripheral nerve stimulation (PNS) of occipital nerves for management of chronic migraine. METHODS: PNS device characteristics (lead length and spacing), surgical techniques including lead orientation (parallel or perpendicular to the nerve), and implantable pulse generator (IPG) placement (upper buttock, abdomen, infraclavicular, or lower axilla) in 157 patients were analyzed to identify any relationship with the AE incidence rate. Number of prior PNS implants performed (NPPIP) by the implanter and its relationship with different AE categories (hardware-related, biological, and stimulation-related events) and frequently observed device/procedure-related AEs (lead migration/fracture/breakage, persistent pain at the lead/IPG location, unintended/undesirable changes in stimulation, infection) were also evaluated. Three-way ANOVA tests were utilized to evaluate the dependence of AE occurrence on the variables described above. RESULTS: IPG pocket locations closer to the lead (e.g. infraclavicular region) were associated with a lower AE incidence rate (p < 0.05). Higher NPPIP was related to lower stimulation- and hardware-related AEs (p < 0.05), frequently observed AEs like lead migration, pain, and infection (p < 0.05), and procedure-related additional surgeries (p < 0.05). CONCLUSION: Implantation of the IPG closer to the lead location was associated with reduced AEs. PNS is a relatively new procedure, and the skill and precision in performing these procedures improves with experience. Our results demonstrate that as the implanter gains more experience with these procedures, a significant reduction in device- and procedure-related AEs may be expected.

Safety and efficacy of peripheral nerve stimulation of the occipital nerves for the management of chronic migraine: long-term results from a randomized, multicenter, double-blinded, controlled study.

BACKGROUND: Recent studies evaluated short-term efficacy and safety of peripheral nerve stimulation (PNS) of the occipital nerves for managing chronic migraine. We present 52-week safety and efficacy results from an open-label extension of a randomized, sham-controlled trial. METHODS: In this institutional review board-approved, randomized, multicenter, double-blinded study, patients were implanted with a neurostimulation system, randomized to an active or control group for 12 weeks, and received open-label treatment for an additional 40 weeks. Outcomes collected included number of headache days, pain intensity, migraine disability assessment (MIDAS), Zung Pain and Distress (PAD), direct patient reports of headache pain relief, quality of life, satisfaction and adverse events. Statistical tests assessed change from baseline to 52 weeks using paired t-tests. Intent-to-treat (ITT) analyses of all patients (N = 157) and analyses of only patients who met criteria for intractable chronic migraine (ICM; N = 125) were performed. RESULTS: Headache days were significantly reduced by 6.7 (±8.4) days in the ITT population (p < 0.001) and by 7.7 (±8.7) days in the ICM population (p < 0.001). The percentages of patients who achieved a 30% and 50% reduction in headache days and/or pain intensity were 59.5% and 47.8%, respectively. MIDAS and Zung PAD scores were significantly reduced for both populations. Excellent or good headache relief was reported by 65.4% of the ITT population and 67.9% of the ICM population. More than half the patients in both cohorts were satisfied with the headache relief provided by the device. A total of 183 device/procedure-related adverse events occurred during the study, of which 18 (8.6%) required hospitalization and 85 (40.7%) required surgical intervention; 70% of patients experienced an adverse event. CONCLUSION: Our results support the 12-month efficacy of PNS of the occipital nerves for headache pain and disability associated with chronic migraine. More emphasis on adverse event mitigation is needed in future research. TRIAL REGISTRATION: Clinical trials.gov (NCT00615342).

Refractory headaches treated with bilateral occipital and temporal region stimulation.

OBJECTIVES: To describe use of bilateral temporal and occipital stimulator leads for a refractory headache disorder. MATERIALS AND METHODS: A 31-year-old female had a 10-year history of chronic, severe occipital and temporal region headaches. The patient underwent permanent implant of an occipital stimulator system that resulted in sustained, compete resolution of her occipital pain. However, she continued to suffer disabling (10/10) temporal region headaches and was bedbound most days of the week. Therefore, bilateral temporal stimulator leads were implanted and tunneled to her internal pulse generator. RESULTS: At 12-month follow-up, the patient enjoyed sustained improvement in her pain scores (8/10) and marked increase in her level of functioning. Taking into account increased activity level, she rated her overall improvement at 50%. Unfortunately, infection and erosion of her right temporal lead necessitated temporal stimulator removal. CONCLUSION: Headache disorders may require stimulation of all painful cephalic regions. However, our success in this case must be considered in light of the technical challenges and expense of placing stimulator leads subcutaneously around the head and neck, including the risk of infection, lead breakage, erosion, and migration.

Attributes associated with patient perceived outcome in an academic chronic pain clinic.

OBJECTIVES: Patient satisfaction is tied to outcome, but there is scant literature on the relationship of patient perceived outcome and attributes of the pain clinic visit, including the patient interaction with the pain management specialist. The primary purpose of this study is to identify attributes of the patient-provider interaction most strongly associated with patient perceived outcome of their clinic visit. The secondary aim is to correlate patient perceived outcome with patient self-rated overall health. METHODS: A patient satisfaction survey conducted via phone approximately 3 weeks after the patient's pain clinic visit. RESULTS: The response rate was 60.2%; 987 patient surveys collected between 2006 and 2010 were used in the analysis. Four factors were significantly associated with the outcome: (1) Explanations by the physician of the patient's condition and treatment, (2) clear instructions regarding post-appointment activities, (3) knowing the patient as a person, and (4) the patient's self-rated health. In terms of the secondary objective, those who answered very good/excellent regarding their self-rated health had an 87% increased odds of better (very good/excellent) outcome of their pain clinic visit (or 1.87 times the odds of better outcome) compared with those who answered poor/fair/good. CONCLUSIONS: Our results suggest that pain physicians may positively impact patient perceived outcomes of clinic visits by explaining the patient's condition and treatment, providing instructions, and taking the time to understand the patient and their values.

Sensitivity of MRI of the spine compared with CT myelography in orthostatic headache with CSF leak.

OBJECTIVE: To investigate the sensitivity of MRI of the spine compared with CT myelography (CTM) in detecting CSF leaks. METHODS: Between July 1998 and October 2010, 12 patients with orthostatic headache and a CTM-confirmed spinal CSF leak underwent an MRI of the spine with and without contrast. Using CTM as the gold standard, we retrospectively investigated the sensitivity of spinal MRI in detecting a CSF leak. RESULTS: Eleven of 12 patients with a CSF leak documented by CTM also had extradural fluid collections on spinal MRI (sensitivity 91.7%). Six patients with extradural fluid collections on spinal MRI also had spinal dural enhancement. CONCLUSION: When compared with the gold standard of CTM, MRI of the spine appears to be a sensitive and less invasive imaging modality for detecting a spinal CSF leak, suggesting that MRI of the spine should be the imaging modality of first choice for the detection of spinal CSF leaks.

Long-term outcome in occipital nerve stimulation patients with medically intractable primary headache disorders.

INTRODUCTION: €‚ Occipital nerve stimulation (ONS) may provide relief for refractory headache disorders. However, scant data exist regarding long-€term ONS outcomes. METHODS: €‚ The methods used were retrospective review of the medical records of all (nonindustry study) patients who were trialed and implanted with occipital nerve stimulator systems at our institution, followed by a phone interview. Up to three attempts were made to contact each patient, and those who were contacted were given the opportunity to participate in a brief phone interview regarding their ONS experience. Data for analysis were gleaned from both the phone interview and the patient's medical records. RESULTS: €‚ Twenty-nine patients underwent a trial of ONS during the 8.5-€year study period. Three patients did not go on to permanent implant, 12 could not be contacted, and 14 participated in the phone interview. Based upon the phone interview (if the patient was contacted) or chart review, ONS was deemed successful in five of the 12 migraine, four of the five cluster headache, and five of the eight miscellaneous headache patients, and therapy was documented as long as 102 months. In one of the 26 patients, success of ONS could not be determined. Among patients deemed to have successful outcomes, headache frequency decreased by 18%, severity by 27%, and migraine disability score by 50%. Fifty-€eight percent of patients required at least one lead revision. DISCUSSION: €‚ These results, although limited by their retrospective nature, suggest that ONS can be effective long term despite technical challenges. The number of patients within each headache subtype was insufficient to draw conclusions regarding the differential effect of ONS. CONCLUSIONS: €‚ Randomized controlled long-€term studies in specific, intractable, primary headache disorders are indicated.