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The field of neurostimulation for the treatment of chronic pain is a rapidly developing area of medicine. Although neurostimulation therapies have advanced significantly as a result of technologic improvements, surgical planning, device placement, and postoperative care are of equal importance to optimize outcomes. This Neurostimulation Appropriateness Consensus Committee (NACC) project intends to provide evidence-based guidance for these often-overlooked areas of neurostimulation practice.Authors were chosen based on their clinical expertise, familiarity with the peer-reviewed literature, research productivity, and contributions to the neuromodulation literature. Section leaders supervised literature searches of MEDLINE, BioMed Central, Current Contents Connect, Embase, International Pharmaceutical Abstracts, Web of Science, Google Scholar, and PubMed from the last NACC publication in 2017 to the present. Identified studies were graded using the United States Preventive Services Task Force criteria for evidence and certainty of net benefit. Recommendations are based on evidence strength and consensus when evidence was scant.This NACC project provides guidance on preoperative assessment, intraoperative techniques, and postoperative management in the form of consensus points with supportive evidence. These results are based on grade of evidence, strength of consensus, and expert opinion.The NACC has given guidance for a surgical plan that encompasses the patient journey from the planning stage through the surgical experience and postoperative care. The overall recommendations are designed to improve efficacy and the safety of patients undergoing these neuromodulation procedures and are intended to apply throughout the international community.

The US Health and Human Services Pain Management Best Practices Inter-Agency Task Force initiated a public–private partnership which led to the publication of its report in 2019. The report emphasized the need for individualized, multimodal, and multidisciplinary approaches to pain management that decrease the over-reliance on opioids, increase access to care, and promote widespread education on pain and substance use disorders. The Task Force specifically called on specialty organizations to work together to develop evidence-based guidelines. In response to this report’s recommendations, a consortium of 14 professional healthcare societies committed to a 2-year project to advance pain management for the surgical patient and improve opioid safety. The modified Delphi process included two rounds of electronic voting and culminated in a live virtual event in February 2021, during which seven common guiding principles were established for acute perioperative pain management. These principles should help to inform local action and future development of clinical practice recommendations.

ObjectiveTo conduct a systematic literature review of dorsal root ganglion (DRG) stimulation for pain.DesignGrade the evidence for DRG stimulation.MethodsAn international, interdisciplinary work group conducted a literature search for DRG stimulation. Abstracts were reviewed to select studies for grading. General inclusion criteria were prospective trials (randomized controlled trials and observational studies) that were not part of a larger or previously reported group. Excluded studies were retrospective, too small, or existed only as abstracts. Studies were graded 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 Preventative Services Task Force level-of-evidence criteria.ResultsDRG stimulation has Level II evidence (moderate) based upon one high-quality pivotal randomized controlled trial and two lower-quality studies.ConclusionsModerate-level evidence supports DRG stimulation for treating chronic focal neuropathic pain and complex regional pain syndrome.

BACKGROUND Cervical spinal cord stimulation (cSCS) is an accepted therapeutic option for radicular upper extremity pain and less commonly for cervical axial pain despite less available literature in comparison with lumbar and lower extremity applications. METHODS This preliminary observational pilot study evaluated the efficacy of cSCS using the monophasic burst pattern in the treatment of both upper extremity radicular pain and axial neck pain. Primary outcome measures were reduction in pain scores, global pain scale (GPS) indices, and neck Oswestry disability index (nODI). RESULTS Of the 23 subjects trialed, 15 went to implantation of cSCS using burst and were followed for 1 year prospectively. Pre- and postprimary outcome measures suggested a statistically (p

Background: Chronic axial spinal pain is one of the major causes of significant disability and health care costs, with facet joints as one of the proven causes of pain. Objective: To provide evidence-based guidance in performing diagnostic and therapeutic facet joint interventions. Methods: The methodology utilized included the development of objectives and key questions with utilization of trustworthy standards. The literature pertaining to all aspects of facet joint interventions, was reviewed, with a best evidence synthesis of available literature and utilizing grading for recommendations. Summary of Evidence and Recommendations: Non-interventional diagnosis: • The level of evidence is II in selecting patients for facet joint nerve blocks at least 3 months after onset and failure of conservative management, with strong strength of recommendation for physical examination and clinical assessment. • The level of evidence is IV for accurate diagnosis of facet joint pain with physical examination based on symptoms and signs, with weak strength of recommendation. Imaging: • The level of evidence is I with strong strength of recommendation, for mandatory fluoroscopic or computed tomography (CT) guidance for all facet joint interventions. • The level of evidence is III with weak strength of recommendation for single photon emission computed tomography (SPECT) . • The level of evidence is V with weak strength of recommendation for scintography, magnetic resonance imaging (MRI), and computed tomography (CT) . Interventional Diagnosis: Lumbar Spine: • The level of evidence is I to II with moderate to strong strength of recommendation for lumbar diagnostic facet joint nerve blocks. • Ten relevant diagnostic accuracy studies with 4 of 10 studies utilizing controlled comparative local anesthetics with concordant pain relief criterion standard of ≥ 80% were included. • The prevalence rates ranged from 27% to 40% with false-positive rates of 27% to 47%, with ≥ 80% pain relief.Limitations: The limitations of these guidelines include a paucity of high-quality studies in the majority of aspects of diagnosis and therapy. Conclusions: These facet joint interventions guidelines were prepared with a comprehensive review of the literature with methodologic quality assessment with determination of level of evidence and strength of recommendations Key words: Chronic spinal pain, interventional techniques, diagnostic blocks, therapeutic interventions, facet joint nerve blocks, intraarticular injections, radiofrequency neurolysis

Many of the patients undergoing interventional procedures have daily regimens of medications including analgesics, muscle relaxants, and other drugs that can have significant additive/synergistic effects during the perioperative period. Further, many patients also present with comorbid states, including obesity, cardiovascular, and pulmonary disease. Consequently, in the perioperative period, a significant number of patients have suffered permanent neurologic injury, hypoxic brain injury, and even death as a result of over sedation, hypoventilation, and spinal cord injury. In addition, physicians are concerned about aspiration, subsequent complications, and as a result, they ask patients to fast for several hours prior to the procedures. Based on extensive literature and consensus, a minimum fasting period is established as 2 hours before a procedure for clear liquids and 4 hours before procedure for light meals, rather than having all patients fast for 8 hours or even fasting beginning at midnight the night before the procedure. Gastrointestinal stimulants, gastric acid secretion blockers, and antacids may be used, even though not routinely recommended. Due to the nature of chronic pain and anxiety, many patients undergoing interventional techniques may require mild to moderate sedation. Deep sedation and/or general anesthesia for most interventional procedures is considered as unsafe, since the patient cannot communicate acute changes in symptoms, thus, resulting in morbidity and mortality, as well as creating compliance issues. We are adapting the published standards of the American Society of Anesthesiologists for monitoring patients under sedation, regardless of the location of the procedure, either office-based, in a surgery center, or a hospital outpatient department. These standards include monitoring of blood pressure, cardiac rhythm, temperature, pulse oximetry, and continuous quantitative end tidal CO2 monitoring. Sedation must be provided either by qualified anesthesia or non-anesthesia providers, with appropriate understanding of the medications, drug interactions, and resuscitative protocols. Key words: Guidelines, sedation, fasting status, monitoring, neurological complications

Chronic axial spinal pain is one of the major causes of significant disability and health care costs, with facet joints as one of the proven causes of pain.To provide evidence-based guidance in performing diagnostic and therapeutic facet joint interventions.The methodology utilized included the development of objectives and key questions with utilization of trustworthy standards. The literature pertaining to all aspects of facet joint interventions, was reviewed, with a best evidence synthesis of available literature and utilizing grading for recommendations.Summary of Evidence and Recommendations:Non-interventional diagnosis: • The level of evidence is II in selecting patients for facet joint nerve blocks at least 3 months after onset and failure of conservative management, with strong strength of recommendation for physical examination and clinical assessment. • The level of evidence is IV for accurate diagnosis of facet joint pain with physical examination based on symptoms and signs, with weak strength of recommendation. Imaging: • The level of evidence is I with strong strength of recommendation, for mandatory fluoroscopic or computed tomography (CT) guidance for all facet joint interventions. • The level of evidence is III with weak strength of recommendation for single photon emission computed tomography (SPECT) . • The level of evidence is V with weak strength of recommendation for scintography, magnetic resonance imaging (MRI), and computed tomography (CT) .Interventional Diagnosis:Lumbar Spine: • The level of evidence is I to II with moderate to strong strength of recommendation for lumbar diagnostic facet joint nerve blocks. • Ten relevant diagnostic accuracy studies with 4 of 10 studies utilizing controlled comparative local anesthetics with concordant pain relief criterion standard of ≥80% were included. • The prevalence rates ranged from 27% to 40% with false-positive rates of 27% to 47%, with ≥80% pain relief.Cervical Spine: • The level of evidence is II with moderate strength of recommendation. • Ten relevant diagnostic accuracy studies, 9 of the 10 studies with either controlled comparative local anesthetic blocks or placebo controls with concordant pain relief with a criterion standard of ≥80% were included. • The prevalence and false-positive rates ranged from 29% to 60% and of 27% to 63%, with high variability. Thoracic Spine: • The level of evidence is II with moderate strength of recommendation. • Three relevant diagnostic accuracy studies, with controlled comparative local anesthetic blocks, with concordant pain relief, with a criterion standard of ≥80% were included. • The prevalence varied from 34% to 48%, whereas false-positive rates varied from 42% to 58%.Therapeutic Facet Joint Interventions: Lumbar Spine: • The level of evidence is II with moderate strength of recommendation for lumbar radiofrequency ablation with inclusion of 11 relevant randomized controlled trials (RCTs) with 2 negative studies and 4 studies with long-term improvement. • The level of evidence is II with moderate strength of recommendation for therapeutic lumbar facet joint nerve blocks with inclusion of 3 relevant randomized controlled trials, with long-term improvement. • The level of evidence is IV with weak strength of recommendation for lumbar facet joint intraarticular injections with inclusion of 9 relevant randomized controlled trials, with majority of them showing lack of effectiveness without the use of local anesthetic. Cervical Spine: • The level of evidence is II with moderate strength of recommendation for cervical radiofrequency ablation with inclusion of one randomized controlled trial with positive results and 2 observational studies with long-term improvement. • The level of evidence is II with moderate strength of recommendation for therapeutic cervical facet joint nerve blocks with inclusion of one relevant randomized controlled trial and 3 observational studies, with long-term improvement. • The level of evidence is V with weak strength of recommendation for cervical intraarticular facet joint injections with inclusion of 3 relevant randomized controlled trials, with 2 observational studies, the majority showing lack of effectiveness, whereas one study with 6-month follow-up, showed lack of long-term improvement. Thoracic Spine: • The level of evidence is III with weak to moderate strength of recommendation with emerging evidence for thoracic radiofrequency ablation with inclusion of one relevant randomized controlled trial and 3 observational studies. • The level of evidence is II with moderate strength of recommendation for thoracic therapeutic facet joint nerve blocks with inclusion of 2 randomized controlled trials and one observational study with long-term improvement. • The level of evidence is III with weak to moderate strength of recommendation for thoracic intraarticular facet joint injections with inclusion of one randomized controlled trial with 6 month follow-up, with emerging evidence. Antithrombotic Therapy: • Facet joint interventions are considered as moderate to low risk procedures; consequently, antithrombotic therapy may be continued based on overall general status. Sedation: • The level of evidence is II with moderate strength of recommendation to avoid opioid analgesics during the diagnosis with interventional techniques. • The level of evidence is II with moderate strength of recommendation that moderate sedation may be utilized for patient comfort and to control anxiety for therapeutic facet joint interventions.The limitations of these guidelines include a paucity of high-quality studies in the majority of aspects of diagnosis and therapy.These facet joint intervention guidelines were prepared with a comprehensive review of the literature with methodologic quality assessment with determination of level of evidence and strength of recommendations.Chronic spinal pain, interventional techniques, diagnostic blocks, therapeutic interventions, facet joint nerve blocks, intraarticular injections, radiofrequency neurolysis.

ObjectiveTo conduct a systematic literature review of spinal cord stimulation (SCS) for pain.DesignGrade the evidence for SCS.MethodsAn international, interdisciplinary work group conducted literature searches, reviewed abstracts, and selected studies for grading. Inclusion/exclusion criteria included randomized controlled trials (RCTs) of patients with intractable pain of greater than one year’s duration. Full studies were graded by two independent reviewers. Excluded studies were retrospective, had small numbers of subjects, or existed only as abstracts. Studies were graded 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 Preventative Services Task Force level-of-evidence criteria.ResultsSCS has Level 1 evidence (strong) for axial back/lumbar radiculopathy or neuralgia (five high-quality RCTs) and complex regional pain syndrome (one high-quality RCT).ConclusionsHigh-level evidence supports SCS for treating chronic pain and complex regional pain syndrome. For patients with failed back surgery syndrome, SCS was more effective than reoperation or medical management. 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.

The administration of opioid analgesics via the intrathecal route is becoming more commonplace for a variety of chronic nonmalignant pathologic pain states. Despite this growing trend, there is very little information available to guide practitioners with regard to patient selection as well as intrathecal drug dosing paradigms. The authors describe the use of a protocol for patient selection, including pretrial preparation, as well as detailed very low-dose chronic intrathecal morphine dosing regimens to treat patients with refractory chronic nonmalignant pain.

Background: Patients with implanted spinal cord stimulators (SCS) present to the anesthesia care team for management at many different points along the care continuum. Currently, the literature is sparse on the perioperative management. What is available is confusing; monopolar electrocautery is contraindicated but often used, full body magnetic resonance imaging (MRI) is safe with particular systems but with other manufactures only head and specific extremities exams are safe. Moreover, there are anesthetizing locations outside of the operating room where implanted SCS can interact with surrounding medical equipment and pose significant risk to patient and device. Objectives: The objective of this review is to present relevant known literature about the safe management of SCS in the perioperative period and to begin to develop recommendations. Study Design: A review of current literature and each manufacturers’ labeling was performed to assess risk of interference and patient harm between SCS and technology used in and around typical anesthetizing locations. Methods: A systematic search of the literature was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. A computerized search was conducted for English articles in print up to April 2016 via PubMed www.ncbi.nlm.nih.gov/pubmed; EMBASE www.embase. com; and Cochrane Library www.thecochranelibrary.com. Search terms included “spinal cord stimulator AND MRI,” “spinal cord stimulator AND ECG,” “spinal cord stimulator AND implanted cardiac device,” “spinal cord stimulator AND electrocautery,” and “spinal cord stimulator AND obstetrics.” In addition, a search of Google and Google Scholar was performed. Websites of SCS manufactures were reviewed. Results: Generalized recommendations include turning the amplitude of the SCS to the lowest possible setting and turning off prior to any procedure. Monopolar electrocautery is contraindicated but is still often utilized; placing grounding pads as far away from the device can reduce the risk to device and patient. Bipolar cautery is favored. Implanted cardiac devices can interfere with SCS, but risks can be minimized. Neuraxial anesthesia can be attempted in a patient with implanted SCS, provided the device is not in the expected path. MRI labeling differences present the biggest difference among SCS manufactures. Medtronic’s SureScan SCS, Boston Scientific’s Precision system, St. Jude’s Proclaim, and Stimwave’s Freedome SCS are full body MRI compatible under specific conditions, while other manufacturers have labeling that restricts exams of the trunk and certain extremities. Limitations: This review was intended to be a comprehensive, cumulative review of recommendations for perioperative SCS management; however, the limitations of a review of this nature is the complete reliance on previously published research and the availability of these studies using the methods outlined. Conclusions: SCS is being used earlier in the treatment algorithm for patients with chronic pain. The anesthesia care team needs working knowledge of where the device resides in the neuraxial space and what risks different medical technologies pose to the patient and device. This understanding will lead to appropriate perioperative management which can reduce risk and improve patient outcomes. Key words: Spinal cord stimulation, perioperative management, MRI, anesthetic considerations, CT scan, interventional pain management

INTRODUCTION: The Neuromodulation Appropriateness Consensus Committee (NACC) is dedicated to improving the safety and efficacy of neuromodulation and thus improving the lives of patients undergoing neuromodulation therapies. With continued innovations in neuromodulation comes the need for evolving reviews of best practices. Dorsal root ganglion (DRG) stimulation has significantly improved the treatment of complex regional pain syndrome (CRPS), among other conditions. Through funding and organizational leadership by the International Neuromodulation Society (INS), the NACC reconvened to develop the best practices consensus document for the selection, implantation and use of DRG stimulation for the treatment of chronic pain syndromes. METHODS: The NACC performed a comprehensive literature search of articles about DRG published from 1995 through June, 2017. A total of 2538 article abstracts were then reviewed, and selected articles graded for strength of evidence based on scoring criteria established by the US Preventive Services Task Force. Graded evidence was considered along with clinical experience to create the best practices consensus and recommendations. RESULTS: The NACC achieved consensus based on peer-reviewed literature and experience to create consensus points to improve patient selection, guide surgical methods, improve post-operative care, and make recommendations for management of patients treated with DRG stimulation. CONCLUSION: The NACC recommendations are intended to improve patient care in the use of this evolving therapy for chronic pain. Clinicians who choose to follow these recommendations may improve outcomes.

Many of the patients undergoing interventional procedures have daily regimens of medications including analgesics, muscle relaxants, and other drugs that can have significant additive/synergistic effects during the perioperative period. Further, many patients also present with comorbid states, including obesity, cardiovascular, and pulmonary disease. Consequently, in the perioperative period, a significant number of patients have suffered permanent neurologic injury, hypoxic brain injury, and even death as a result of over sedation, hypoventilation, and spinal cord injury. In addition, physicians are concerned about aspiration, subsequent complications, and as a result, they ask patients to fast for several hours prior to the procedures. Based on extensive literature and consensus, a minimum fasting period is established as 2 hours before a procedure for clear liquids and 4 hours before procedure for light meals, rather than having all patients fast for 8 hours or even fasting beginning at midnight the night before the procedure. Gastrointestinal stimulants, gastric acid secretion blockers, and antacids may be used, even though not routinely recommended. Due to the nature of chronic pain and anxiety, many patients undergoing interventional techniques may require mild to moderate sedation. Deep sedation and/or general anesthesia for most interventional procedures is considered as unsafe, since the patient cannot communicate acute changes in symptoms, thus, resulting in morbidity and mortality, as well as creating compliance issues. We are adapting the published standards of the American Society of Anesthesiologists for monitoring patients under sedation, regardless of the location of the procedure, either office-based, in a surgery center, or a hospital outpatient department. These standards include monitoring of blood pressure, cardiac rhythm, temperature, pulse oximetry, and continuous quantitative end tidal CO2 monitoring. Sedation must be provided either by qualified anesthesia or non-anesthesia providers, with appropriate understanding of the medications, drug interactions, and resuscitative protocols.KEY WORDS: Guidelines, sedation, fasting status, monitoring, neurological complications.

Background: Interventional pain management involves diagnosis and treatment of chronic pain. This specialty utilizes minimally invasive procedures to target therapeutics to the central nervous system and the spinal column. A subset of patients encountered in interventional pain are medicated using anticoagulant or antithrombotic drugs to mitigate thrombosis risk. Since these drugs target the clotting system, bleeding risk is a consideration accompanying interventional procedures. Importantly, discontinuation of anticoagulant or antithrombotic drugs exposes underlying thrombosis risk, which can lead to significant morbidity and mortality especially in those with coronary artery or cerebrovascular disease. This review summarizes the literature and provides guidelines based on best evidence for patients receiving anti-clotting therapy during interventional pain procedures. Study Design: Best evidence synthesis. Objective: To provide a current and concise appraisal of the literature regarding an assessment of the bleeding risk during interventional techniques for patients taking anticoagulant and/or antithrombotic medications. Methods: A review of the available literature published on bleeding risk during interventional pain procedures, practice patterns and perioperative management of anticoagulant and antithrombotic therapy was conducted. Data sources included relevant literature identified through searches of EMBASE and PubMed from 1966 through August 2018 and manual searches of the bibliographies of known primary and review articles. Results: 1. There is good evidence for risk stratification by categorizing multiple interventional techniques into low-risk, moderate-risk, and high-risk. Also, their risk should be upgraded based on other risk factors. 2. There is good evidence for the risk of thromboembolic events in patients who interrupt antithrombotic therapy. 3. There is good evidence supporting discontinuation of low dose aspirin for high risk and moderate risk procedures for at least 3 days, and there is moderate evidence that these may be continued for low risk or some intermediate risk procedures.4. There is good evidence that discontinuation of anticoagulant therapy with warfarin, heparin, dabigatran (Pradaxa®), argatroban (Acova®), bivalirudin (Angiomax®), lepirudin (Refludan®), desirudin (Iprivask®), hirudin, apixaban (Eliquis®), rivaroxaban (Xarelto®), edoxaban (Savaysa®, Lixiana®), Betrixaban(Bevyxxa®), fondaparinux (Arixtra®) prior to interventional techniques with individual consideration of pharmacokinetics and pharmacodynamics of the drugs and individual risk factors increases safety. 5. There is good evidence that diagnosis of epidural hematoma is based on severe pain at the site of the injection, rapid neurological deterioration, and MRI with surgical decompression with progressive neurological dysfunction to avoid neurological sequelae. 6. There is good evidence that if thromboembolic risk is high, low molecular weight heparin bridge therapy can be instituted during cessation of the anticoagulant, and the low molecular weight heparin can be discontinued 24 hours before the pain procedure. 7. There is fair evidence that the risk of thromboembolic events is higher than that of epidural hematoma formation with the interruption of antiplatelet therapy preceding interventional techniques, though both risks are significant. 8. There is fair evidence that multiple variables including anatomic pathology with spinal stenosis and ankylosing spondylitis; high risk procedures and moderate risk procedures combined with anatomic risk factors; bleeding observed during the procedure, and multiple attempts during the procedures increase the risk for bleeding complications and epidural hematoma. 9. There is fair evidence that discontinuation of phosphodiesterase inhibitors is optional (dipyridamole [Persantine], cilostazol [Pletal]. However, there is also fair evidence to discontinue Aggrenox [dipyridamole plus aspirin]) 3 days prior to undergoing interventional techniques of moderate and high risk. 10. There is fair evidence to make shared decision making between the patient and the treating physicians with the treating physician and to consider all the appropriate risks associated with continuation or discontinuation of antithrombotic or anticoagulant therapy. 11. There is fair evidence that if thromboembolic risk is high antithrombotic therapy may be resumed 12 hours after the interventional procedure is performed. 12. There is limited evidence that discontinuation of antiplatelet therapy (clopidogrel [Plavix®], ticlopidine [Ticlid®], Ticagrelor [Brilinta®] and prasugrel [Effient®]) avoids complications of significant bleeding and epidural hematomas. 13. There is very limited evidence supporting the continuation or discontinuation of most NSAIDs, excluding aspirin, for 1 to 2 days and some 4 to 10 days, since these are utilized for pain management without cardiac or cerebral protective effect. Limitations: The continued paucity of the literature with discordant recommendations. Conclusion: Based on the survey of current literature, and published clinical guidelines, recommendations for patients presenting with ongoing antithrombotic therapy prior to interventional techniques are variable, and are based on comprehensive analysis of each patient and the risk-benefit analysis of intervention. Key words: Perioperative bleeding, bleeding risk, practice patterns, anticoagulant therapy, antithrombotic therapy, interventional techniques, safety precautions, pain

The benefits of opioid therapy must be balanced by any adverse effects. In recent years, prescription opioids have been increasingly prescribed, but have also been associated with increased abuse, overdose and death.This review will categorize the common risks of opioid administration. Recognized adverse effects of opioid therapy include constipation, tolerance, endocrinopathies, sleep disorders, cognitive effects, respiratory depression, overdose and addiction. Studies have shown that there is increased risk of overdose and death with higher daily opioid doses, particularly above a morphine equivalent oral daily dose of 100 milligrams. Extended-release/long acting (ER/LA) opioid formulations may be beneficial for the compliant patient, yet may expose a higher risk for abuse if used inappropriately since each tablet carries a larger dose of medication.Prospective, controlled one-year trials are needed to establish the efficacy and safety profile of chronic opioid therapy. In addition to the well known side effects of chronic opioid therapy, the influence and serious effect of opioids on sleep and central sleep apnea is only recently being investigated. The lowest possible daily opioid must be used to manage chronic pain, and all clinicians should be cautious in the use of daily morphine equivalent doses above 50-100 milligrams.

Intrathecal drug delivery has become a commonplace means to treat recalcitrant chronic pain of malignant and nonmalignant origins. Although intrathecal drug delivery systems (IDDS) and intrathecal drug delivery (IDD) itself rapidly established themselves in the treatment of malignant pain at the end of life, these therapies are also utilized for treatment of pain of nonmalignant origin. While the only US Food and Drug Administration (FDA)-approved medications for use in the intrathecal space are morphine, baclofen, and ziconotide, this chapter will also address commonly used medications such as clonidine and local anesthetics such as bupivacaine as well. While this chapter serves as general overview of the topic’s long history and rapidly developing literature, a basic understanding of the modality and medications used is important.

Background Lumbar spinal stenosis (LSS) can lead to compression of neural elements and manifest as low back and leg pain. LSS has traditionally been treated with a variety of conservative (pain medications, physical therapy, epidural spinal injections) and invasive (surgical decompression) options. Recently, several minimally invasive procedures have expanded the treatment options. Methods The Lumbar Spinal Stenosis Consensus Group convened to evaluate the peer-reviewed literature as the basis for making minimally invasive spine treatment (MIST) recommendations. Eleven consensus points were clearly defined with evidence strength, recommendation grade, and consensus level using U.S. Preventive Services Task Force criteria. The Consensus Group also created a treatment algorithm. Literature searches yielded 9 studies (2 randomized controlled trials [RCTs]; 7 observational studies, 4 prospective and 3 retrospective) of minimally invasive spine treatments, and 1 RCT for spacers. Results The LSS treatment choice is dependent on the degree of stenosis; spinal or anatomic level; architecture of the stenosis; severity of the symptoms; failed, past, less invasive treatments; previous fusions or other open surgical approaches; and patient comorbidities. There is Level I evidence for percutaneous image-guided lumbar decompression as superior to lumbar epidural steroid injection, and 1 RCT supported spacer use in a noninferiority study comparing 2 spacer products currently available. Conclusions MISTs should be used in a judicious and algorithmic fashion to treat LSS, based on the evidence of efficacy and safety in the peer-reviewed literature. The MIST Consensus Group recommend that these procedures be used in a multimodal fashion as part of an evidence-based decision algorithm.

Patients with implanted spinal cord stimulators (SCS) present to the anesthesia care team for management at many different points along the care continuum. Currently, the literature is sparse on the perioperative management. What is available is confusing; monopolar electrocautery is contraindicated but often used, full body magnetic resonance imaging (MRI) is safe with particular systems but with other manufactures only head and specific extremities exams are safe. Moreover, there are anesthetizing locations outside of the operating room where implanted SCS can interact with surrounding medical equipment and pose significant risk to patient and device.The objective of this review is to present relevant known literature about the safe management of SCS in the perioperative period and to begin to develop recommendations.A review of current literature and each manufacturers' labeling was performed to assess risk of interference and patient harm between SCS and technology used in and around typical anesthetizing locations.A systematic search of the literature was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. A computerized search was conducted for English articles in print up to April 2016 via PubMed www.ncbi.nlm.nih.gov/pubmed; EMBASE www.embase.com; and Cochrane Library www.thecochranelibrary.com. Search terms included "spinal cord stimulator AND MRI," "spinal cord stimulator AND ECG," "spinal cord stimulator AND implanted cardiac device," "spinal cord stimulator AND electrocautery," and "spinal cord stimulator AND obstetrics." In addition, a search of Google and Google Scholar was performed. Websites of SCS manufactures were reviewed.Generalized recommendations include turning the amplitude of the SCS to the lowest possible SETTING and turning off prior to any procedure. Monopolar electrocautery is contraindicated but is still often utilized; placing grounding pads as far away from the device can reduce the risk to device and patient. Bipolar cautery is favored. Implanted cardiac devices can interfere with SCS, but risks can be minimized. Neuraxial anesthesia can be attempted in a patient with implanted SCS, provided the device is not in the expected path. MRI labeling differences present the biggest difference among SCS manufactures. Medtronic's SureScan SCS, Boston Scientific's Precision system, St. Jude's Proclaim, and Stimwave's Freedome SCS are full body MRI compatible under specific conditions, while other manufacturers have labeling that restricts exams of the trunk and certain extremities.This review was intended to be a comprehensive, cumulative review of recommendations for perioperative SCS management; however, the limitations of a review of this nature is the complete reliance on previously published research and the availability of these studies using the methods outlined.SCS is being used earlier in the treatment algorithm for patients with chronic pain. The anesthesia care team needs working knowledge of where the device resides in the neuraxial space and what risks different medical technologies pose to the patient and device. This understanding will lead to appropriate perioperative management which can reduce risk and improve patient outcomes.

Objective The education of physicians is a fundamental obligation within medicine that must remain closely aligned with clinical care. And although medical education in pain care is essential, the current state of medical education does not meet the needs of physicians, patients, or society. To address this, we convened a committee of pain specialist medical student educators. Methods Tasked with creating systematically developed and valid recommendations for clinical education, we conducted a survey of pain medicine leadership within the American Academy of Pain Medicine (AAPM). The survey was conducted in two waves. We asked AAPM board members to rate 194 previously published pain medicine learning objectives for medical students; 79% of those eligible for participation responded. Results The “Top 5” list included the awareness of acute and chronic pain, skillfulness in clinical appraisal, promotion of compassionate practices, displaying empathy toward the patient, and knowledge of terms and definitions for substance abuse. The “Top 10” list included the major pharmacological classes as well as skills in examination, communication, prescribing, and interviewing. The “Top 20” list included the pain care of cognitively impaired populations, those with comorbid illness, and older adults. With the survey results in consideration, the committee produced a new recommended topic list for curricula in pain medicine. We strongly recommend that adequate resources are devoted to fully integrated medical curricula in pain so that students will learn not only the necessary clinical knowledge but also be prepared to address the professional, personal, and ethical challenges that arise in caring for those with pain. Conclusions We conclude that improved medical education in pain is essential to prepare providers who manifest both competence and compassion toward their patients.

Recent advances in spinal cord stimulation have resulted in new stimulation platforms, which hold great promise in expanding the capabilities of implantable neuromodulation, to produce analgesia for a wider array of patients and patient syndromes. Traditionally, tonic stimulation at low frequencies has resulted in improved analgesia and function for those suffering from neuropathic pain syndromes to include neuropathy, failed back surgery syndrome, complex regional pain syndrome, and angina/vascular insufficiency. Multiple attempts to improve analgesia for those suffering from mechanical or nociceptive pain with stimulation have proven elusive. The application of higher frequency rates in spinal cord stimulation has, in preliminary work, shown promise for low back pain, while maintaining efficacy for neuropathic pain syndromes. This chapter examines one of the theories put forth regarding new stimulation platforms, specifically that frequency alone is not the critical concept, but the combination of pulse width, frequency, and amplitude resulting in increased charge delivery to the target tissue may be key in understanding how to provide better analgesia to patients with nociceptive and neuropathic pain.

Background: Intrathecal baclofen has been an effective therapy in the management of spasticity. As interventional pain physicians are rapidly becoming the experts in intrathecal drug delivery, they are now frequently asked to trial and implant intrathecal baclofen therapy. While some physicians might be very comfortable with the process of trialing and implanting, others will have next to no experience until the first consult appears on their desks. While uncomplicated lower extremity spasticity can usually be trialed with a single-shot bolus injection, more complicated cases of upper and lower extremities or hemiparetic spasticity need a more delicate approach. This is the first case series in the literature reporting a trial using an indwelling temporary catheter and inpatient admission. Moreover, while the technical aspects of intrathecal therapy trialing and implantation might be familiar for the interventional physician, we review the indications and goals of therapy, about which the physician may be less familiar. Objective: To present a technique for trialing intrathecal baclofen in patients with severe upper and lower extremities spasticity complication for which a single shot technique may be inadequate. Design: Case report of three patients. Setting: Tertiary-care referral medical center. Patients: A 30-year-old man with severe spasticity of the right upper and lower extremities with preserved left-sided function due to diffuse axonal injury. A 45-year-old woman with traumatic brain injury and severe spasticity of the left upper extremity with minimal dysfunction in the right upper extremity. A 34-year-old woman with Multiple Sclerosis and severe spasticity in the right upper extremity and bilateral lower extremities. Intervention: Placement of a temporary intrathecal catheter and an inpatient trial of intrathecal baclofen. Results: In all patients, there was significant improvement in spasticity as documented by decreased Modified Ashworth Scale scores while preserving motor strength and coordination in the unaffected extremities. Limitations: Retrospective review of 3 cases in a single center. Conclusions: Trialing for baclofen is usually performed as a single shot bolus. For patients with severe hemiparetic spasticity or in patients where weakness in the unaffected limb might significantly affect quality of life, this trialing technique may be inadequate. In these patients, placement of a temporary intrathecal catheter and inpatient admission may be a more effective trial method. Key words: Baclofen, intrathecal drug delivery, spasticity, multiple sclerosis, traumatic brain injury

Background: Various methods exist for trialing patients for intrathecal drug delivery. Currently no standards exist regarding “best practices” for trialing techniques. Objectives: The specific aim of the current study is to report results of patients trialed using a low-dose intrathecal morphine technique in the treatment of chronic noncancer pain. Setting: academic pain medicine practice Study Design: Retrospective Review Method: Visual analog pain scores (VAS) were obtained at the initial visit, after a 6 week opioid-free interval prior to trial, at intrathecal doses of 25, 50, 100, 200 and 400 µg of intrathecal morphine during the trial, at one month post-implant, and current VAS. Additionally, intrathecal opioid doses at implant and current state are reported. Results: VAS scores at the initial visit and after 6 weeks of opioid cessation were identical. There was a significant improvement in VAS after the trial, which was sustained over the course of therapy. Additionally, the use of the protocol described in this article suggests that the doseresponse relationship following opioid cessation is in the 50-400 µg/d range for intrathecal morphine and that tolerance may be reversed during the 6 week opioid-free period. Limitations: Small trialing study Conclusions: Opioid taper and a 6 week opioid-free period may 1) improve long-term analgesia versus a combination of oral/ intrathecal drug delivery system therapy 2) it may be possible to maintain analgesia at microgram doses and 3) opioid tolerance may be reversible in 6 weeks. Further it appears that a dose response relationship for effective analgesia may be less than 400 µg of intrathecal morphine. Key Words: Intrathecal opioids, intrathecal drug delivery, oral opioid therapy, chronic noncancer pain

Background: Spinal cord stimulators are most often placed through a percutaneous approach using minimal sedation and local anesthesia to facilitate intraoperative testing. However, when leads need to be placed using a laminectomy incision additional anesthesia is required which can complicate intraoperative testing. There is no consensus as to the best anesthetic choice when laminectomy-placed leads are required. Objective: We present 2 cases where spinal cord stimulator leads were implanted through a surgical laminectomy under sedation using dexmedetomidine infusion and local anesthesia to provide a cooperative patient for intraoperative testing. Case Report: Patient #1: A 40-year-old female with Complex Regional Pain Syndrome secondary to an automobile accident who had good pain control with a spinal cord stimulator until a lead fracture resulted in loss of stimulation. She required a laminectomy-placed lead which was implanted under dexmedetomidine infusion and local anesthesia. Patient #2: A 54-year-old female with Failed Back Syndrome who had good pain control until a lead fracture resulted in loss of stimulation. She underwent a laminectomy-placed lead, new battery pocket, and removal of the old system under a dexmedetomidine infusion and local anesthesia. Limitations: Report of only 2 cases. Conclusions: The anesthetic management from a laminectomy-placed spinal cord stimulator can present a difficult choice. A general anesthetic or even deep sedation can provide good operative conditions but limits intraoperative testing or in the case of deep sedation risks losing the airway in the prone position. On the other hand, minimal sedation, which facilitates intraoperative testing, can make the surgical procedure extremely uncomfortable or even unbearable. Dexmedetomidine infusion and local anesthesia provide sedation for the operative portions while rendering the patient alert and cooperative during intraoperative testing. Key words: Spinal Cord Stimulator, dexmedetomidine, percutaneous, laminectomy, intraoperative, sedation

Chronic neuropathic pain has been recognized as contributing to a significant proportion of chronic pain globally. Among these, spinal pain is of significance with failed back surgery syndrome (FBSS), generating considerable expense for the health care systems with increasing prevalence and health impact.To assess the role and effectiveness of spinal cord stimulation (SCS) in chronic spinal pain.A systematic review of randomized controlled trials (RCTs) of SCS in chronic spinal pain.The available literature on SCS was reviewed. The quality assessment criteria utilized were Cochrane review criteria to assess sources of risk of bias and Interventional Pain Management Techniques - Quality Appraisal of Reliability and Risk of Bias Assessment (IPM - QRB) criteria for randomized trials.The level of evidence was based on a best evidence synthesis with modified grading of qualitative evidence from Level I to Level V.Data sources included relevant literature published from 1966 through March 2015 that were identified through searches of PubMed and EMBASE, manual searches of the bibliographies of known primary and review articles, and all other sources.RCTs of efficacy with a minimum 12-month follow-up were considered for inclusion. For trials of adaptive stimulation, high frequency stimulation, and burst stimulation, shorter follow-up periods were considered.Results showed 6 RCTs with 3 efficacy trials and 3 stimulation trials. There were also 2 cost effectiveness studies available. Based on a best evidence synthesis with 3 high quality RCTs, the evidence of efficacy for SCS in lumbar FBSS is Level I to II. The evidence for high frequency stimulation based on one high quality RCT is Level II to III. Based on a lack of high quality studies demonstrating the efficacy of adaptive stimulation or burst stimulation, evidence is limited for these 2 modalities.The limitations of this systematic review continue to require future studies illustrating effectiveness and also the superiority of high frequency stimulation and potentially burst stimulation.There is significant (Level I to II) evidence of the efficacy of spinal cord stimulation in lumbar FBSS; whereas, there is moderate (Level II to III) evidence for high frequency stimulation; there is limited evidence for adaptive stimulation and burst stimulation.

This study presents the survivorship data of a consecutive series of primary meniscal-bearing total knee replacements at one institution at 8 to 15 years followup. We reviewed 125 meniscal-bearing knee replacements in 93 patients at a minimum followup of 96 months (mean, 130 months; range, 96-191 months). The tibial and femoral components were cemented in 71 knees; uncemented femurs and tibias were used in 48 knees; and cemented tibias and uncemented femurs were used in six knees. One patient was lost to followup. Seventeen knees failed, three as a result of infection. Five knees were revised for loose tibial components and one for a loose femoral component. A second femoral component was identified as radiographically loose. All the loose components were uncemented. Five knees had reoperation for fractured bearings and one for a dislocated bearing. This knee was later rerevised for a loose uncemented tibia. One knee was revised for instability and a second knee was identified as grossly unstable but not revised. Kaplan-Meier survival analysis showed survivorship of approximately 90% at 9 years, which decreased to 71% at 15 years. Uncemented components had an increased aseptic loosening rate compared with cemented components. Meniscal-bearing replacements with cement fixation appeared successful, although bearing fracture seems to be a predominant failure mode at long-term followup.

Despite the prevalence of acute pain in the trauma setting and known complications of its improper management, including risk of chronic pain, delayed recovery, and poorer quality of life, recent survey data suggest little has changed in the overall management of pain in the acute setting during the

Objective To evaluate low-dose intrathecal opioid trialing and maintenance with regard to analgesia and psychometric functional capacity. Materials and Methods Prospective cohort of subjects offered, trialed and maintained using low-dose opioid therapy via an intrathecal drug delivery system. Analgesia, measured by visual analog scale and the Global Pain Scale, and function, measured by Multidimensional Pain Inventory and Global Pain Scale, are evaluated. Population analysis by age, gender, oral opioid dose, diagnosis, and pain type is reported. Results Fifty-eight subjects enrolled in the 36-month evaluation period with mean opioid intrathecal opioid dose less than 350 μg per day of morphine equivalent utilized. Primary nociceptive pain type were associated with lower intrathecal opioid doses and improved visual analog scale pain rating and improved pain severity and interference on the Multidimensional Pain Inventory. Conclusions This study adds to the growing body of literature suggesting that low-dose intrathecal analgesia without oral opioid supplementation can be efficacious. It appears that this approach may achieve analgesia with lower doses in those with primary nociceptive pain type

Objective Stiff-person syndrome (SPS) is a rare disorder of the central nervous system characterized by stiffness and muscle spasms that may be progressive in nature. When oral medication is inadequate to control muscle spasticity, intrathecal baclofen may be used. We report a patient with severe SPS and glutamate decarboxylase negative [GAD(−)] (note: GAD(−) indicates the patient has no antibodies to GAD), refractory to oral standard therapies. The patient was effectively trialed with an intrathecal catheter and subsequently treated with chronic intrathecal baclofen, which provided significant relief of spasticity symptoms. Case Report A 48-year-old white man with a history consistent with SPS presented to the clinic. His previous history showed that he met several diagnostic criteria for GAD(−) SPS and had a muscle biopsy positive for myositis. Oral medications were unable to control his muscle spasticity, preventing him from working. The patient received an intrathecal trial using a lumbar approach for placement of a thoracic catheter with an initial baclofen dose of 50 μg/d. Gradual titration to symptom relief was performed up to 150 μg/d. Functional evaluation by our physical therapist showed improved motor function, the temporary catheter was removed, and a permanent intrathecal pump placed for intrathecal baclofen infusion. The patient reported excellent symptom relief over the next 6 months and improved activity. Conclusions Refractory SPS is difficult to treat and has few therapeutic options. We report a GAD(−) patient with SPS and resulting debilitating spasticity that was refractory to oral medications who underwent successful continuous intrathecal catheter trial of baclofen over 4 days and subsequently went on to implantation of intrathecal pump. The literature reports only 5 cases of GAD(−) SPS patients treated with intrathecal baclofen therapy, and these resulted in poor long-term success. Our patient completed a 4-day trial of intrathecal baclofen titrated to effect before pump implantation. We advocate continuous intrathecal trialing, as opposed to single-injection technique, to possibly better determine the effective therapeutic dose and ensure posttrialing successful therapy.

Intrathecal baclofen has been an effective therapy in the management of spasticity. As interventional pain physicians are rapidly becoming the experts in intrathecal drug delivery, they are now frequently asked to trial and implant intrathecal baclofen therapy. While some physicians might be very comfortable with the process of trialing and implanting, others will have next to no experience until the first consult appears on their desks. While uncomplicated lower extremity spasticity can usually be trialed with a single-shot bolus injection, more complicated cases of upper and lower extremities or hemiparetic spasticity need a more delicate approach. This is the first case series in the literature reporting a trial using an indwelling temporary catheter and inpatient admission. Moreover, while the technical aspects of intrathecal therapy trialing and implantation might be familiar for the interventional physician, we review the indications and goals of therapy, about which the physician may be less familiar.To present a technique for trialing intrathecal baclofen in patients with severe upper and lower extremities spasticity complication for which a single shot technique may be inadequate.Case report of three patients.Tertiary-care referral medical center.A 30-year-old man with severe spasticity of the right upper and lower extremities with preserved left-sided function due to diffuse axonal injury. A 45-year-old woman with traumatic brain injury and severe spasticity of the left upper extremity with minimal dysfunction in the right upper extremity. A 34-year-old woman with Multiple Sclerosis and severe spasticity in the right upper extremity and bilateral lower extremities.Placement of a temporary intrathecal catheter and an inpatient trial of intrathecal baclofen.In all patients, there was significant improvement in spasticity as documented by decreased Modified Ashworth Scale scores while preserving motor strength and coordination in the unaffected extremities.Retrospective review of 3 cases in a single center.Trialing for baclofen is usually performed as a single shot bolus. For patients with severe hemiparetic spasticity or in patients where weakness in the unaffected limb might significantly affect quality of life, this trialing technique may be inadequate. In these patients, placement of a temporary intrathecal catheter and inpatient admission may be a more effective trial method.

Spinal anesthesia has been a safe and popular anesthetic option for patients undergoing outpatient surgical procedures of the trunk and lower extremities. Occasionally, after a spinal anesthetic, patients can develop moderate-to-severe pain in the back, hips, and legs without neurologic deficit. They will often present to the emergency department with complaints of pain and require an extensive diagnostic workup to rule out other more ominous possibilities such as spinal hematoma, infection, or nerve injury. After a negative workup and with a history of recent spinal anesthetic the patient will be diagnosed with transient neurologic syndrome. While often causing significant distress to both the patient and health care provider, transient neurologic syndrome is a benign, self-limited entity that requires only conservative therapy and usually resolves within a couple of days without intervention.

Various methods exist for trialing patients for intrathecal drug delivery. Currently no standards exist regarding "best practices" for trialing techniques.The specific aim of the current study is to report results of patients trialed using a low-dose intrathecal morphine technique in the treatment of chronic noncancer pain.academic pain medicine practiceRetrospective ReviewVisual analog pain scores (VAS) were obtained at the initial visit, after a 6 week opioid-free interval prior to trial, at intrathecal doses of 25, 50, 100, 200 and 400 μg of intrathecal morphine during the trial, at one month post-implant, and current VAS. Additionally, intrathecal opioid doses at implant and current state are reported.VAS scores at the initial visit and after 6 weeks of opioid cessation were identical. There was a significant improvement in VAS after the trial, which was sustained over the course of therapy. Additionally, the use of the protocol described in this article suggests that the dose-response relationship following opioid cessation is in the 50-400 μg/d range for intrathecal morphine and that tolerance may be reversed during the 6 week opioid-free period.Small trialing studyOpioid taper and a 6 week opioid-free period may 1) improve long-term analgesia versus a combination of oral/ intrathecal drug delivery system therapy 2) it may be possible to maintain analgesia at microgram doses and 3) opioid tolerance may be reversible in 6 weeks. Further it appears that a dose response relationship for effective analgesia may be less than 400 μg of intrathecal morphine.

Objective To compare the results of continuous epidural bupivacaine analgesia with and without hydromorphone to continuous paravertebral analgesia with bupivcaine in patients with post-thoracotomy pain. Design A prospective, randomized, double-blinded trial. Setting A teaching hospital. Participants Patients at a tertiary care teaching hospital undergoing throracotomy for lung cancer. Interventions Subjects were assigned randomly to receive a continuous thoracic epidural or paravertebral infusion. Patients in the epidural group were randomized to receive either bupivacaine alone or in combination with hydromorphone. Visual analog scores as well as incentive spirometery results were obtained before and after thoracotomy. Methods and Main Results Seventy-five consecutive patients presenting for thoracotomy were enrolled in this institutional review board–approved study. On the morning of surgery, subjects were randomized to either an epidural group receiving bupvicaine with and without hydromorphone or a paravertebral catheter–infused bupvicaine. Postoperative visual analog scores and incentive spirometry data were measured in the postanesthesia care unit, the evening of the first operative day, and daily thereafter until postoperative day 4. Analgesia on all postoperative days was superior in the thoracic epidural group receiving bupivacaine plus hydromorphone. Analgesia was similar in the epidural and continuous paravertebral groups receiving bupivacaine alone. No significant improvement was noted by combining the continuous infusion of bupivacaine via the paravertebral and epidural routes. Incentive spirometry goals were best achieved in the epidural bupivacaine and hydromorphone group and equal in the group receiving bupivacaine alone either via epidural or continuous paravertebral infusion. Conclusions The current study provided data that fill gaps in the current literature in 3 important areas. First, this study found that thoracic epidural analgesia (TEA) with bupivacaine and a hydrophilic opioid, hydromorphone, may provide enhanced analgesia over TEA or continuous paravertebral infusion (CPI) with bupivacaine alone. Second, in the bupivacaine-alone group, the increased basal rates required to achieve analgesia resulted in hypotension more frequently than in the bupivacaine/hydromorphone combination group, underscoring the benefit of the synergistic activity. Finally, in agreement with previous retrospective studies, the current data suggest that CPI of local anesthetic appears to provide acceptable analgesia for post-thoracotomy pain.

Spinal cord stimulators are most often placed through a percutaneous approach using minimal sedation and local anesthesia to facilitate intraoperative testing. However, when leads need to be placed using a laminectomy incision additional anesthesia is required which can complicate intraoperative testing. There is no consensus as to the best anesthetic choice when laminectomy-placed leads are required.We present 2 cases where spinal cord stimulator leads were implanted through a surgical laminectomy under sedation using dexmedetomidine infusion and local anesthesia to provide a cooperative patient for intraoperative testing.Patient #1: A 40-year-old female with Complex Regional Pain Syndrome secondary to an automobile accident who had good pain control with a spinal cord stimulator until a lead fracture resulted in loss of stimulation. She required a laminectomy-placed lead which was implanted under dexmedetomidine infusion and local anesthesia. Patient #2: A 54-year-old female with Failed Back Syndrome who had good pain control until a lead fracture resulted in loss of stimulation. She underwent a laminectomy-placed lead, new battery pocket, and removal of the old system under a dexmedetomidine infusion and local anesthesia.Report of only 2 cases.The anesthetic management from a laminectomy-placed spinal cord stimulator can present a difficult choice. A general anesthetic or even deep sedation can provide good operative conditions but limits intraoperative testing or in the case of deep sedation risks losing the airway in the prone position. On the other hand, minimal sedation, which facilitates intraoperative testing, can make the surgical procedure extremely uncomfortable or even unbearable. Dexmedetomidine infusion and local anesthesia provide sedation for the operative portions while rendering the patient alert and cooperative during intraoperative testing.

Repeated methamphetamine (METH) administration to animals can result in long-lasting decreases in striatal dopamine (DA) content. It has previously been shown that glial cell line-derived neurotrophic factor (GDNF) can reduce the DA-depleting effects of neurotoxic doses of METH. However, there are several other trophic factors that are protective against dopaminergic toxins. Thus, the present experiments further investigated the protective effect of GDNF as well as the protective effects of several other trophic factors. Male Fischer-344 rats were given an intracerebral injection of trophic factor (2-10 microg) 1 day before METH (5 mg/kg, s.c., 4 injections at 2-h intervals). Seven days later DA levels in the striatum were measured using high-performance liquid chromatography (HPLC). Initial experiments indicated that only intrastriatal GDNF, and not intranigral GDNF, was protective. Thereafter, all other trophic factors were administered into the striatum. Members of the GDNF family (GDNF, neurturin, and artemin) all provided significant protection against the DA-depleting effects of METH, with GDNF providing the greatest protection. Brain-derived neurotrophic factor, neurotrophin-3, acidic fibroblast growth factor, basic fibroblast growth factor, ciliary neurotrophic factor, transforming growth factor-alpha (TGF-alpha), heregulin beta1 (HRG-beta1), and amphiregulin (AR) provided no significant protection at the doses examined. These results suggest that the GDNF family of trophic factors can provide significant protection against the DA-depleting effects of neurotoxic doses of METH.

HIV-1 infection of the brain can lead to the development of clinical syndromes reminiscent of Parkinson’s disease, suggesting that HIV infection may damage nigrostriatal dopamine (DA) neurons. Although the responsible mechanisms have not been well defined, neurotoxic viral proteins, such as Tat, released from infected cells may be involved. Drug abuse is a major risk factor for contracting HIV infection. Methamphetamine (METH), a psychostimulant with high abuse potential, may also be toxic to brain DA neurons. Thus, the combination of METH abuse and HIV infection may lead to substantial alterations in DA neuron functioning. The present experiments examined how Tat, alone and with METH, affects DA release in the striatum. Male rats were given an intrastriatal injection of Tat (25 μg) or vehicle 24 h before treatment with saline or neurotoxic doses of METH. Seven days later microdialysis studies were carried out to measure potassium- and amphetamine-evoked overflow of DA from the striatum. The Tat treatment alone led to no change in potassium-evoked overflow of DA, a 20% decrease in amphetamine-evoked overflow of DA, and a 16% decrease in striatal DA content. The METH alone led to a 37–42% decrease in striatal DA overflow and content. The combined treatment with Tat and METH led to significantly greater 70–78% decreases in striatal DA overflow and content. These results indicate that Tat enhances METH-induced reductions in striatal DA release and content, possibly in a synergistic manner, and suggest that METH abusers infected with HIV may be at increased risk for basal ganglia dysfunction.

Nigrostriatal dopamine neurons degenerate during aging, and the excessive loss of dopamine neurons that occurs with Parkinson's disease is usually confined to older individuals. Although 6-hydroxydopamine lesioning of the nigrostriatal dopamine system is a common method for producing animal models of dopamine neuron degeneration, there have been relatively few studies that have examined the effects of 6-hydroxydopamine on the dopamine systems of aged animals. The present experiments were designed to determine if nigrostriatal dopamine neurons in aged rats are more sensitive to the neurotoxic effects of 6-hydroxydopamine than those of younger rats. Young (4-month-old), middle-aged (14-month-old) and aged (24-month-old) Fischer-344 rats were given a single injection of vehicle, 50 or 100 microg 6-hydroxydopamine into the right lateral ventricle. Three to four weeks later in vivo electrochemistry was used to measure potassium-evoked overflow of dopamine in the striatum. In the young rats the 50-microg dose had no significant effect on evoked overflow of dopamine in the striatum or on post-mortem levels of dopamine in the striatum or substantia nigra. The higher dose in the young animals diminished evoked overflow of dopamine as well as tissue levels of dopamine. In the aged rats both doses of 6-hydroxydopamine led to significant decreases in evoked overflow of striatal dopamine and in tissue levels of dopamine in the striatum and substantia nigra. These results suggest that dopamine neurons of aged Fischer-344 rats are more susceptible to the toxic effects of 6-hydroxydopamine than those of younger animals.