A trigeminovagal complex, as described in some animals, could help to explain the effect of vagus... more A trigeminovagal complex, as described in some animals, could help to explain the effect of vagus nerve stimulation as a treatment for headache disorders. However, the existence of a trigeminovagal complex in humans remains unclear. This study, therefore investigated the existence of the trigeminovagal complex in humans. One post-mortem human brainstem was scanned at 11.7T to obtain structural (T1-weighted) and diffusion magnetic resonance images ((d)MR images). Post-processing of dMRI data provided track density imaging (TDI) maps to investigate white matter at a smaller resolution than the imaging resolution. To evaluate the reconstructed tracts, the MR-scanned brainstem and three additional brainstems were sectioned for polarized light imaging (PLI) microscopy. T1-weighted images showed hyperintense vagus medullar striae, coursing towards the dorsomedial aspect of the medulla. dMRI-, TDI- and PLI-images showed these striae to intersect the trigeminal spinal tract (sp5) in the lat...
Intrathecal drug delivery is a useful and effective treatment for a variety of painful conditions... more Intrathecal drug delivery is a useful and effective treatment for a variety of painful conditions. Knowledge and understanding of the risks as well as the benefits of IDD treatment is crucial for successful patient care.
Background: Chronic pain is a common and growing problem in the United States with variable strat... more Background: Chronic pain is a common and growing problem in the United States with variable strategies for its treatment. Surgical interventions are necessary in some cases but not required for all patients with new-onset pain. For some patients, interventional pain management (IPM) techniques can treat chronic pain without the cost or risk associated with surgical intervention. Objective: The objective of this study was to compare healthcare utilization and costs for new-onset chronic pain treated by IPM specialists to those treated by providers with surgical specialties (i.e., orthopedists and neurosurgeons). Study design: This was a retrospective observational study of qualifying patients over 36-months (2016-2019). Setting: This study was conducted using 100% Medicare FFS Parts A, B, and Prescription Drug Event (PDE) Part D data, including enrollment and claims. Methods: Patients with a diagnosis of pain were identified in the claims data. Twelve months of pre-period claims were examined to ensure the incident diagnosis of pain, and 2 additional pain diagnoses were required after initial diagnosis. Patients were assigned either to the IPM cohort or a Surgical cohort based on the specialty of the provider involved in their first pain-related visit after initial diagnosis. Key outcomes, such as the utilization of healthcare services and cost of care, were evaluated for both cohorts over the 24-months following the index diagnosis of pain. Results: 106,658 beneficiaries were included in the study with roughly 36% in the IPM cohort. Patients in the IPM cohort were less healthy and had lower incomes in the baseline period compared to the Surgical cohort. Fewer members of the IPM cohort had an inpatient stay in the 24-months post index pain diagnosis (40% compared to 43% in the surgery cohort) and the IPM cohort had fewer patients with a post-acute care stay (29% compared to 31% in the inpatient stay cohort). The IPM cohort had lower risk-adjusted total costs of care than the Surgical cohort, driven by lower inpatient, outpatient, and post-acute care costs. Limitations: Retrospective claims data may not include some factors important to patients with a pain diagnosis (such as over-the-counter medications, holistic treatments, or pain scores). Conclusion(s): By shifting patients from higher-cost and more invasive surgical procedures, IPM's multidisciplinary approach to pain treatment can reduce surgical utilization and costs for certain chronic pain patients. This shift away from more expensive surgical treatments fits well with Medicare's move toward value-based care, driven by a focus on patient outcomes including health care utilization and costs.
Complex regional pain syndrome (CRPS) represents a state of constant and often disabling pain, af... more Complex regional pain syndrome (CRPS) represents a state of constant and often disabling pain, affecting one region (usually hand) and often occurs after a trauma whose severity does not correlate with the level of pain. The older term for this condition of chronic pain associated with motor and autonomic symptoms is reflex sympathetic dystrophy or causalgia. The aim of this review, based on contemporary literature, is to show the epidemiology and etiology, proposed pathophysiological mechanisms, method of diagnosis and treatment options, prevention and mitigation of this under-recognized disease. CRPS I occurs without known neurological damage, unlike CRPS II, where the history of trauma is present and in some cases damage to the peripheral nervous system can be objectively assessed using electromyoneurography. New diagnostic methods, such as quantitative sensory testing (CST), challenge this division because the CST findings in patients with CRPS I can suggest damage to Adelta peripheral nerve fibers. Except for distinguishing type I and type II disease, it is important to bear in mind the diversity of clinical presentation of CRPS in acute and chronic phase of the disease. This regional pain syndrome typically includes the autonomic and motor signs and thus differs from other peripheral neuropathic pain syndromes. The complexity of the clinical presentation indicates the likely presence of different pathophysiological mechanisms underlying this disease. Previous studies have demonstrated the autonomic dysfunction, neurogenic inflammation and neuroplastic changes. The diagnosis of CRPS is based on anamnesis and clinical examination on the basis of which the disease can be graded according to the Budapest Criteria. A valuable aid in differentiating subtypes of the disease is electromyoneurography. The treatment of CRPS is as complex as the clinical picture and the pathophysiology of the disease and requires interdisciplinary cooperation and individual approach. The pharmacological approach is mainly symptomatic, including analgesics, glucocorticoids, baclofen, bisphosphonates and prophylactic administration of vitamin C. Physical therapy besides preventing atrophy and contractures reduces the use of analgesic therapy. Invasive approach includes stimulation of the spinal cord, peripheral nerve catheters with anesthetic and amputation that patients in severe condition gladly accept. Further research is needed to better understand the disease and more effective therapies.
Abstract Interventional, neurosurgical, and—on the horizon—molecular neurosurgical procedures can... more Abstract Interventional, neurosurgical, and—on the horizon—molecular neurosurgical procedures can supplement pharmacological and complementary approaches to treat cancer pain. Of the approximately 500,000 patients who die each year from cancer, 5%-15% suffer from poor pain control. Implantable drug delivery systems and highly specific, highly efficacious, nonaddictive, long-acting neurolysis (now being tested in clinical trials), may optimize pain management while minimizing side effects, enhancing quality of life, improving survival, and potentially reducing costs in this patient population. These techniques are ideal for patients for whom efforts to manage severe adverse effects are unsuccessful due to dose-limiting side effects (e.g., systemic opioids causing refractory constipation, nausea, vomiting, or sedation). With proper patient selection and consideration of a patient's medical condition, therapeutic effects can be optimized while complications are minimized.
Chronic pain is one of the leading health-care crises in America today, affecting more patients t... more Chronic pain is one of the leading health-care crises in America today, affecting more patients than cancer and heart disease combined. In response to uncontrolled pain, the use of prescription opioid analgesics has soared, resulting in a second problem, one of addiction. In order to optimally treat patients with pain, while minimizing the risks of abuse diversion or addiction, it is important to establish an accurate diagnosis and design the most appropriate treatment plan. Moreover there are multiple strategies that are known to be effective in pain. A thorough understanding of the options available to physicians is likely to improve pain control and minimize risks.
Michael H. Levy, MD: This 38-year-old white male first came to his physician in January of 1993 c... more Michael H. Levy, MD: This 38-year-old white male first came to his physician in January of 1993 complaining of epigastric and low back pain. In March of 1993, he was diagnosed with pancreatic cancer that was metastatic to his
Prescription drug abuse in the USA claims over 16,000 lives annually. The risk of overdose is rea... more Prescription drug abuse in the USA claims over 16,000 lives annually. The risk of overdose is real, and most deaths are unintentional. Multiple risk factors exist independent of the medication used (medical and psychiatric comorbidities). Treatment of opioid overdose can be accomplished with nasal or injectable naloxone. Laypersons can be trained to recognize opioid overdose and treat it immediately; however, emergency responders should be called immediately upon a witnessed overdose (911) and appropriate medical care provided at a facility.
Stimulation in the human somatosensory thalamus, posteroinferior to the human principal sensory n... more Stimulation in the human somatosensory thalamus, posteroinferior to the human principal sensory nucleus (ventralis caudalis), has been reported to reproduce previously experienced pain associated with a strong affective dimension. In these reports, pains with a strong affective dimension were reproduced by stimulation within and posteroinferior to the core (posteroinferior region) of the ventralis caudalis only in patients with previous experience of such pain. Similar vivid experiential responses have been reported with stimulation over the parasylvian cortex. Thus, the connection from the posteroinferior region to the secondary somatosensory cortex and insular cortex may explain the reproduction, by thalamic stimulation, of pain with a strong affective dimension. The secondary somatosensory and insular cortex are involved in nociceptive pathways that have similar characteristics to cortical areas known to be involved in visual memory through corticolimbic connections. Therefore, stimulation-evoked pain with a strong affective dimension may be explained by a model in which limbic structures are altered by previous experience of pain with a strong affective dimension and triggered, through thalamic corticolimbic connections, to reproduce that pain. This sensorylimbic model could form the framework for testable hypotheses regarding the anatomic and physiologic substrates of learning processes involved in the affective dimension of pain.
ObjectiveThis prospective longitudinal study compares outcomes between Medicare beneficiaries rec... more ObjectiveThis prospective longitudinal study compares outcomes between Medicare beneficiaries receiving percutaneous image‐guided lumbar decompression (PILD) using the mild® procedure and a control group of patients receiving interspinous spacers for the treatment of lumbar spinal stenosis (LSS) with neurogenic claudication (NC).MethodsPatients diagnosed with LSS with NC and treated with either the mild procedure or a spacer were identified in the Medicare claims database. The incidence of harms, the rate of subsequent interventions, and the overall combined rate of harms and subsequent interventions during 2‐year follow‐up after the index procedure were compared between the two groups and assessed for statistical significance with p = 0.05.ResultsThe study included 2229 patients in the mild group and 3401 patients who were implanted with interspinous spacers. The rate of harms for those treated with the mild procedure was less than half that of patients implanted with a spacer (5.6% vs. 12.1%, respectively; p < 0.0001) during 2‐year follow‐up. The rate of subsequent interventions was not significantly different between the two groups (24.9% and 26.1% for the mild and spacer groups, respectively; p = 0.7679). The total rate of harms and subsequent interventions for mild was found to be noninferior to spacers (p < 0.0001).ConclusionsThis comprehensive study of real‐world Medicare claims data demonstrated a significantly lower rate of harms for the mild procedure compared to interspinous spacers for patients diagnosed with LSS with NC, and a similar rate of subsequent interventions during 2‐year follow‐up.
Objectives: The effectiveness of Evoke closed-loop spinal cord stimulation (CL-SCS), a novel moda... more Objectives: The effectiveness of Evoke closed-loop spinal cord stimulation (CL-SCS), a novel modality of neurostimulation, has been demonstrated in a randomized controlled trial (RCT). The objective of this cost-utility analysis was to develop a de novo economic model to estimate the cost-effectiveness of Evoke CL-SCS when compared with open-loop SCS (OL-SCS) for the management of chronic back and leg pain. Methods: A decision tree followed by a Markov model was used to estimate the costs and outcomes of Evoke CL-SCS versus OL-SCS over a 15-year time horizon from the UK National Health Service perspective. A “high-responder” health state was included to reflect improved levels of SCS pain reduction recently reported. Results are expressed as incremental cost per quality-adjusted life year (QALY). Deterministic and probabilistic sensitivity analysis (PSA) was conducted to assess uncertainty in the model inputs. Results: Evoke CL-SCS was estimated to be the dominant treatment strategy at ~5 years postimplant (ie, it generates more QALYs while cost saving compared with OL-SCS). Probabilistic sensitivity analysis showed that Evoke CL-SCS has a 92% likelihood of being cost-effective at a willingness to pay threshold of £20,000/QALY. Results were robust across a wide range of scenario and sensitivity analyses. Discussion: The results indicate a strong economic case for the use of Evoke CL-SCS in the management of chronic back and leg pain with or without prior spinal surgery with dominance observed at ~5 years.
A trigeminovagal complex, as described in some animals, could help to explain the effect of vagus... more A trigeminovagal complex, as described in some animals, could help to explain the effect of vagus nerve stimulation as a treatment for headache disorders. However, the existence of a trigeminovagal complex in humans remains unclear. This study, therefore investigated the existence of the trigeminovagal complex in humans. One post-mortem human brainstem was scanned at 11.7T to obtain structural (T1-weighted) and diffusion magnetic resonance images ((d)MR images). Post-processing of dMRI data provided track density imaging (TDI) maps to investigate white matter at a smaller resolution than the imaging resolution. To evaluate the reconstructed tracts, the MR-scanned brainstem and three additional brainstems were sectioned for polarized light imaging (PLI) microscopy. T1-weighted images showed hyperintense vagus medullar striae, coursing towards the dorsomedial aspect of the medulla. dMRI-, TDI- and PLI-images showed these striae to intersect the trigeminal spinal tract (sp5) in the lat...
Intrathecal drug delivery is a useful and effective treatment for a variety of painful conditions... more Intrathecal drug delivery is a useful and effective treatment for a variety of painful conditions. Knowledge and understanding of the risks as well as the benefits of IDD treatment is crucial for successful patient care.
Background: Chronic pain is a common and growing problem in the United States with variable strat... more Background: Chronic pain is a common and growing problem in the United States with variable strategies for its treatment. Surgical interventions are necessary in some cases but not required for all patients with new-onset pain. For some patients, interventional pain management (IPM) techniques can treat chronic pain without the cost or risk associated with surgical intervention. Objective: The objective of this study was to compare healthcare utilization and costs for new-onset chronic pain treated by IPM specialists to those treated by providers with surgical specialties (i.e., orthopedists and neurosurgeons). Study design: This was a retrospective observational study of qualifying patients over 36-months (2016-2019). Setting: This study was conducted using 100% Medicare FFS Parts A, B, and Prescription Drug Event (PDE) Part D data, including enrollment and claims. Methods: Patients with a diagnosis of pain were identified in the claims data. Twelve months of pre-period claims were examined to ensure the incident diagnosis of pain, and 2 additional pain diagnoses were required after initial diagnosis. Patients were assigned either to the IPM cohort or a Surgical cohort based on the specialty of the provider involved in their first pain-related visit after initial diagnosis. Key outcomes, such as the utilization of healthcare services and cost of care, were evaluated for both cohorts over the 24-months following the index diagnosis of pain. Results: 106,658 beneficiaries were included in the study with roughly 36% in the IPM cohort. Patients in the IPM cohort were less healthy and had lower incomes in the baseline period compared to the Surgical cohort. Fewer members of the IPM cohort had an inpatient stay in the 24-months post index pain diagnosis (40% compared to 43% in the surgery cohort) and the IPM cohort had fewer patients with a post-acute care stay (29% compared to 31% in the inpatient stay cohort). The IPM cohort had lower risk-adjusted total costs of care than the Surgical cohort, driven by lower inpatient, outpatient, and post-acute care costs. Limitations: Retrospective claims data may not include some factors important to patients with a pain diagnosis (such as over-the-counter medications, holistic treatments, or pain scores). Conclusion(s): By shifting patients from higher-cost and more invasive surgical procedures, IPM's multidisciplinary approach to pain treatment can reduce surgical utilization and costs for certain chronic pain patients. This shift away from more expensive surgical treatments fits well with Medicare's move toward value-based care, driven by a focus on patient outcomes including health care utilization and costs.
Complex regional pain syndrome (CRPS) represents a state of constant and often disabling pain, af... more Complex regional pain syndrome (CRPS) represents a state of constant and often disabling pain, affecting one region (usually hand) and often occurs after a trauma whose severity does not correlate with the level of pain. The older term for this condition of chronic pain associated with motor and autonomic symptoms is reflex sympathetic dystrophy or causalgia. The aim of this review, based on contemporary literature, is to show the epidemiology and etiology, proposed pathophysiological mechanisms, method of diagnosis and treatment options, prevention and mitigation of this under-recognized disease. CRPS I occurs without known neurological damage, unlike CRPS II, where the history of trauma is present and in some cases damage to the peripheral nervous system can be objectively assessed using electromyoneurography. New diagnostic methods, such as quantitative sensory testing (CST), challenge this division because the CST findings in patients with CRPS I can suggest damage to Adelta peripheral nerve fibers. Except for distinguishing type I and type II disease, it is important to bear in mind the diversity of clinical presentation of CRPS in acute and chronic phase of the disease. This regional pain syndrome typically includes the autonomic and motor signs and thus differs from other peripheral neuropathic pain syndromes. The complexity of the clinical presentation indicates the likely presence of different pathophysiological mechanisms underlying this disease. Previous studies have demonstrated the autonomic dysfunction, neurogenic inflammation and neuroplastic changes. The diagnosis of CRPS is based on anamnesis and clinical examination on the basis of which the disease can be graded according to the Budapest Criteria. A valuable aid in differentiating subtypes of the disease is electromyoneurography. The treatment of CRPS is as complex as the clinical picture and the pathophysiology of the disease and requires interdisciplinary cooperation and individual approach. The pharmacological approach is mainly symptomatic, including analgesics, glucocorticoids, baclofen, bisphosphonates and prophylactic administration of vitamin C. Physical therapy besides preventing atrophy and contractures reduces the use of analgesic therapy. Invasive approach includes stimulation of the spinal cord, peripheral nerve catheters with anesthetic and amputation that patients in severe condition gladly accept. Further research is needed to better understand the disease and more effective therapies.
Abstract Interventional, neurosurgical, and—on the horizon—molecular neurosurgical procedures can... more Abstract Interventional, neurosurgical, and—on the horizon—molecular neurosurgical procedures can supplement pharmacological and complementary approaches to treat cancer pain. Of the approximately 500,000 patients who die each year from cancer, 5%-15% suffer from poor pain control. Implantable drug delivery systems and highly specific, highly efficacious, nonaddictive, long-acting neurolysis (now being tested in clinical trials), may optimize pain management while minimizing side effects, enhancing quality of life, improving survival, and potentially reducing costs in this patient population. These techniques are ideal for patients for whom efforts to manage severe adverse effects are unsuccessful due to dose-limiting side effects (e.g., systemic opioids causing refractory constipation, nausea, vomiting, or sedation). With proper patient selection and consideration of a patient's medical condition, therapeutic effects can be optimized while complications are minimized.
Chronic pain is one of the leading health-care crises in America today, affecting more patients t... more Chronic pain is one of the leading health-care crises in America today, affecting more patients than cancer and heart disease combined. In response to uncontrolled pain, the use of prescription opioid analgesics has soared, resulting in a second problem, one of addiction. In order to optimally treat patients with pain, while minimizing the risks of abuse diversion or addiction, it is important to establish an accurate diagnosis and design the most appropriate treatment plan. Moreover there are multiple strategies that are known to be effective in pain. A thorough understanding of the options available to physicians is likely to improve pain control and minimize risks.
Michael H. Levy, MD: This 38-year-old white male first came to his physician in January of 1993 c... more Michael H. Levy, MD: This 38-year-old white male first came to his physician in January of 1993 complaining of epigastric and low back pain. In March of 1993, he was diagnosed with pancreatic cancer that was metastatic to his
Prescription drug abuse in the USA claims over 16,000 lives annually. The risk of overdose is rea... more Prescription drug abuse in the USA claims over 16,000 lives annually. The risk of overdose is real, and most deaths are unintentional. Multiple risk factors exist independent of the medication used (medical and psychiatric comorbidities). Treatment of opioid overdose can be accomplished with nasal or injectable naloxone. Laypersons can be trained to recognize opioid overdose and treat it immediately; however, emergency responders should be called immediately upon a witnessed overdose (911) and appropriate medical care provided at a facility.
Stimulation in the human somatosensory thalamus, posteroinferior to the human principal sensory n... more Stimulation in the human somatosensory thalamus, posteroinferior to the human principal sensory nucleus (ventralis caudalis), has been reported to reproduce previously experienced pain associated with a strong affective dimension. In these reports, pains with a strong affective dimension were reproduced by stimulation within and posteroinferior to the core (posteroinferior region) of the ventralis caudalis only in patients with previous experience of such pain. Similar vivid experiential responses have been reported with stimulation over the parasylvian cortex. Thus, the connection from the posteroinferior region to the secondary somatosensory cortex and insular cortex may explain the reproduction, by thalamic stimulation, of pain with a strong affective dimension. The secondary somatosensory and insular cortex are involved in nociceptive pathways that have similar characteristics to cortical areas known to be involved in visual memory through corticolimbic connections. Therefore, stimulation-evoked pain with a strong affective dimension may be explained by a model in which limbic structures are altered by previous experience of pain with a strong affective dimension and triggered, through thalamic corticolimbic connections, to reproduce that pain. This sensorylimbic model could form the framework for testable hypotheses regarding the anatomic and physiologic substrates of learning processes involved in the affective dimension of pain.
ObjectiveThis prospective longitudinal study compares outcomes between Medicare beneficiaries rec... more ObjectiveThis prospective longitudinal study compares outcomes between Medicare beneficiaries receiving percutaneous image‐guided lumbar decompression (PILD) using the mild® procedure and a control group of patients receiving interspinous spacers for the treatment of lumbar spinal stenosis (LSS) with neurogenic claudication (NC).MethodsPatients diagnosed with LSS with NC and treated with either the mild procedure or a spacer were identified in the Medicare claims database. The incidence of harms, the rate of subsequent interventions, and the overall combined rate of harms and subsequent interventions during 2‐year follow‐up after the index procedure were compared between the two groups and assessed for statistical significance with p = 0.05.ResultsThe study included 2229 patients in the mild group and 3401 patients who were implanted with interspinous spacers. The rate of harms for those treated with the mild procedure was less than half that of patients implanted with a spacer (5.6% vs. 12.1%, respectively; p < 0.0001) during 2‐year follow‐up. The rate of subsequent interventions was not significantly different between the two groups (24.9% and 26.1% for the mild and spacer groups, respectively; p = 0.7679). The total rate of harms and subsequent interventions for mild was found to be noninferior to spacers (p < 0.0001).ConclusionsThis comprehensive study of real‐world Medicare claims data demonstrated a significantly lower rate of harms for the mild procedure compared to interspinous spacers for patients diagnosed with LSS with NC, and a similar rate of subsequent interventions during 2‐year follow‐up.
Objectives: The effectiveness of Evoke closed-loop spinal cord stimulation (CL-SCS), a novel moda... more Objectives: The effectiveness of Evoke closed-loop spinal cord stimulation (CL-SCS), a novel modality of neurostimulation, has been demonstrated in a randomized controlled trial (RCT). The objective of this cost-utility analysis was to develop a de novo economic model to estimate the cost-effectiveness of Evoke CL-SCS when compared with open-loop SCS (OL-SCS) for the management of chronic back and leg pain. Methods: A decision tree followed by a Markov model was used to estimate the costs and outcomes of Evoke CL-SCS versus OL-SCS over a 15-year time horizon from the UK National Health Service perspective. A “high-responder” health state was included to reflect improved levels of SCS pain reduction recently reported. Results are expressed as incremental cost per quality-adjusted life year (QALY). Deterministic and probabilistic sensitivity analysis (PSA) was conducted to assess uncertainty in the model inputs. Results: Evoke CL-SCS was estimated to be the dominant treatment strategy at ~5 years postimplant (ie, it generates more QALYs while cost saving compared with OL-SCS). Probabilistic sensitivity analysis showed that Evoke CL-SCS has a 92% likelihood of being cost-effective at a willingness to pay threshold of £20,000/QALY. Results were robust across a wide range of scenario and sensitivity analyses. Discussion: The results indicate a strong economic case for the use of Evoke CL-SCS in the management of chronic back and leg pain with or without prior spinal surgery with dominance observed at ~5 years.
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