Howard S Smith’s research while affiliated with Albany Medical College and other places

The palliative patient poses multiple challenges to the caregiver, calling not only for the most feasible medical options, but also reconciling patient wishes, family’s beliefs and pragmatism. Occasionally, severe debilitating pain secondary to systemic disease processes, radiation and/or chemotherapy necessitates the use of multiple infusions of potent opioids and other medications to achieve palliation, which not only potentially cloud the patient’s mental status during end-of-life, impeding familial communication, but often mandate inpatient care. When traditional pain interventions have failed, neurosurgical interventions should be considered. This chapter reviews various neurosurgical interventions available to the palliative pain patient who has failed traditional pain management strategies. Specifically, we discuss ablative procedures—cordotomy, myelotomy and denervation—and intrathecal therapies.

Neuromodulation is a burgeoning and exciting field that offers potential for innovative applications in medicine. The International Neuromodulation Society defines neuromodulation as electrical or chemical alteration of signal transmission within the nervous system by using implanted devices to affect improvement in symptoms and render optimal functioning to improve quality of life (Sakas et al. , 2007). Currently, spinal cord stimulation (SCS) leads the way as the most common application of neuromodulation, predominantly in cases of complex regional pain syndrome (CRPS) and failed back surgery syndrome (FBSS). Motor cortex stimulation (MCS) and peripheral nerve stimulation (PNS) have also been used for treatment of intractable pain syndromes. Historically, even deep brain stimulation (DBS) has been employed for pain despite its most established application in current treatment of movement disorders such as Parkinson’s disease (PD). Neuromodulation of pain in palliative care, though not advocated previously because of cost and questionable efficacy with disease progression, may provide significant relief to many patients, especially as survival expectancy increases. This population typically has diminished organ reserve and particular vulnerability to drug-drug interactions from the exorbitant number of medications prescribed to manage conditions as well as the associated side effects from these medications. Thus, using a different modality of treatment such as an electrical stimulation device may be quite beneficial. Here, we explore the pre-clinical and clinical data that support the potential use of neuromodulation in palliation. We discuss the major modalities of stimulation (DBS, MCS, SCS, and PNS), examine their current uses, and assess the noted effects on refractory debilitating symptoms which may benefit people at the end of life. In addition, we outline the current limitations to widespread application of neuromodulation in palliative medicine.

The future of neuromodulation shows incredible potential and will likely demonstrate greater integration of various techniques as adjunctive therapy to already accepted standard of care management. Extensive research continues on current applications of neuromodulation such as movement disorders, while new indications are also being investigated. These new indications include depression, obsessive-compulsive disorder, impulsivity disorders, addiction, eating disorders, obesity, tinnitus, blood pressure control and traumatic brain injury. In addition, neuromodulation may have a potential role in palliative care medicine. Patients in this sector often suffer from significantly distressing symptoms that have a common basis to some of those pathologies mentioned above. If effective, neuromodulatory techniques could alleviate these symptoms and facilitate a better quality of life for the patient’s remaining time. Here, we discuss the potential roles of neuromodulation by way of deep brain stimulation (DBS), motor cortex stimulation (MCS), spinal cord stimulation (SCS) and peripheral nerve stimulation (PNS). These various modalities are examined for refractory symptoms of dyspnea, gastrointestinal (GI) dysfunction, motor deficits, depression, delirium, mentation and sleep disturbance in palliative care patients. We review discovery of incidental amelioration of symptoms, current knowledge on mechanism of action specific to modality, analysis of results reported in literature, limitations of data, barriers to application and future research. Many of the advances in functional neurosurgery have come from unintended benefits while treating other conditions and we suspect that increasing use of neuromodulation will result in similar findings of relief for other symptoms. It is an exciting time to be involved in neuromodulation as we seek to improve quality at end of life.

This chapter presents a clinical case of fibromyalgia in which the patient may experience profound suffering, including widespread musculoskeletal pain and stiffness, fatigue, disturbed sleep, and possible cognitive alterations/abnormalities (dyscognition), affective distress, and very poor quality of life. Two different specific pathogenic mechanisms that may lead to a low pain threshold in fibromyalgia and that have been identified using experimental pain testing are increased wind-up or temporal summation and a reduction of descending analgesic activity. The chapter discusses the epidemiology, prognosis, pathophysiology, and diagnostic criteria of the condition. Techniques for managing fibromyalgia include pharmacotherapy, exercise, patient education, cognitive-behavioral therapy, relaxation techniques, biofeedback, and patient self-care. The chapter also discusses methods for managing depression, a psychiatric comorbidity of fibromyalgia.

Patients requiring chronic opioid therapy may not respond to or tolerate the first opioid prescribed to them, necessitating rotation to another opioid. They may also require dose increases for a number of reasons, including worsening disease and increased pain. Dose escalation to restore analgesia using the primary opioid may lead to increased adverse events. In these patients, rotation to a different opioid at a lower-than-equivalent dose may be sufficient to maintain adequate tolerability and analgesia. In published trials and case series, opioid rotation is performed either using a predetermined substitute opioid with fixed conversion methods, or in a manner that appears to be no more systematic than trial and error. In clinical practice, opioid rotation must be performed with consideration of individual patient characteristics, comorbidities (eg, concurrent psychiatric, pulmonary, renal, or hepatic illness), and concurrent medications, using flexible dosing protocols that take into account incomplete opioid cross-tolerance. References cited in this review were identified via a search of PubMed covering all English language publications up to May 21, 2013 pertaining to opioid rotation, excluding narrative reviews, letters, and expert opinion. The search yielded a total of 129 articles, 92 of which were judged to provide relevant information and subsequently included in this review. Through a review of this literature and from the authors’ empiric experience, this review provides practical information on performing opioid rotation in clinical practice.

Chronic pain is a highly prevalent medical problem in the United States. Although opioids and serotonin-norepinephrine reuptake inhibitors (SNRIs) have demonstrated efficacy for relief of chronic pain, each has risks of adverse events in patients. Because of the risk of opioid abuse and addiction, combinations reducing opioid requirements are particularly valuable. Opioid and SNRI agents relieve pain by different pathways; concurrent use of each agent separately offers many potential benefits: complementary and possibly synergistic analgesic efficacy, separate titrations of opioid and SNRI effects, and the reduction of opioid requirements. However, few clinical studies have investigated the ideal ratios for combinations of opioids and SNRIs. A number of factors affect whether specific combinations have additive, synergistic, less than additive efficacy, or increase adverse events in patients, including general pharmacokinetic considerations, the potential for pharmacodynamic drug interactions, dose, and timing. Because there is little clinical evidence guiding combination therapy with separate opioid and SNRI agents, using single-molecule agents provides safe and effective therapy and should be the first option presented to patients. The use of empiric combinations of separate opioid and SNRI combinations needs to be considered in light of clinical cautions, including the lack of published evidence to guide dose conversion from any opioid to tramadol or to tapentadol, and vice versa; the need to avoid combinations with known drug interactions; and the need to titrate the dose when adding an SNRI to an opioid, and vice versa.

Post dural puncture headache (PDPH) is a common complication of interventional neuraxial procedures. Larger needle gauge, younger patients, low body mass index, women (especially pregnant women), and "traumatic" needle types are all associated with a higher incidence of PDPH. Currently, an epidural blood patch is the gold-standard treatment for this complication. However, despite the high PDPH cure rate through the use of this therapy, little is known about the physiology behind the success of the epidural blood patch, specifically, the time course of patch formation within the epidural space or how long it takes for the blood patch volume to be resorbed by the body. Of the many unanswered and debated topics related to PDPH and epidural blood patches, one additional specific question that may alter clinical management is when it is safe for patients who have experienced a disruption of the thecal space and have undergone this procedure to have a subsequent epidural or spinal procedure, such as a neuraxial anesthetic (i.e. a spinal anesthetic for an elective outpatient procedure) or an interventional pain procedure for chronic pain management. This question becomes more unclear if the new procedure includes a steroid medication. As an example, an older patient presents with a history of lumbar disc disease and during lumbar epidural steroid injection, an inadvertent wet tap occurs leading to PDPH. Following management with fluids, caffeine, medications, and a successful epidural blood patch, it remains unclear as to when would be the best time frame to consider a second lumbar epidural steroid injection. We identified the 3 main risk factors of subsequent interventional neuraxial procedures as (1) disruption of the epidural blood patch and ongoing reparative processes, (2) epidural procedure failure, and (3) infection. We looked at the literature, and summarized the existing literature in order to enable health care professionals to understand the time course of dural repair as well as the risks of subsequent neuraxial procedures after epidural blood patches. This review poses the question using an evidence based review to discuss the appropriate time course to proceed.