Review of the History and Current Status of Cell-Transplant Approaches for the Management of Neuropathic Pain

Treatment of sensory neuropathies, whether inherited or caused by trauma, the progress of diabetes, or other disease states, are among the most difficult problems in modern clinical practice. Cell therapy to release antinociceptive agents near the injured spinal cord would be the logical next step in the development of treatment modalities. But few clinical trials, especially for chronic pain, have tested the transplant of cells or a cell line to treat human disease. The history of the research and development of useful cell-transplant-based approaches offers an understanding of the advantages and problems associated with these technologies, but as an adjuvant or replacement for current pharmacological treatments, cell therapy is a likely near future clinical tool for improved health care

Deep Brain Stimulation Improves the Symptoms and Sensory Signs of Persistent Central Neuropathic Pain from Spinal Cord Injury: A Case Report

Central neuropathic pain (CNP) is a significant problem after spinal cord injury (SCI). Pharmacological and non-pharmacological approaches may reduce the severity, but relief is rarely substantial. While deep brain stimulation (DBS) has been used to treat various chronic pain types, the technique has rarely been used to attenuate CNP after SCI. Here we present the case of a 54-year-old female with incomplete paraplegia who had severe CNP in the lower limbs and buttock areas since her injury 30 years prior. She was treated with bilateral DBS of the midbrain periaqueductal gray (PAG). The effects of this stimulation on CNP characteristics, severity and pain-related sensory function were evaluated using the International SCI Pain Basic Data Set (ISCIPBDS), Neuropathic Pain Symptom Inventory (NPSI), Multidimensional Pain Inventory and Quantitative Sensory Testing before and periodically after initiation of DBS. After starting DBS treatment, weekly CNP severity ratings rapidly decreased from severe to minimal, paralleled by a substantial reduction in size of the painful area, reduced pain impact and reversal of pain-related neurological abnormalities, i.e., dynamic-mechanical and cold allodynia. She discontinued pain medication on study week 24. The improvement has been consistent. The present study expands on previous findings by providing in-depth assessments of symptoms and signs associated with CNP. The results of this study suggest that activation of endogenous pain inhibitory systems linked to the PAG can eliminate CNP in some people with SCI. More research is needed to better-select appropriate candidates for this type of therapy. We discuss the implications of these findings for understanding the brainstem’s control of chronic pain and for future progress in using analgesic DBS in the central gray

The assessment and treatment of pain syndromes in neurorehabilitation

Persistent pains associated with injuries or disease involving the central nervous system (CNS), are common. In order to optimally manage persistent pain the primary underlying mechanisms need to be determined and the treatment targeted to these. A�comprehensive pain evaluation including symptoms, sensory function/dysfunction, and psychosocial factors is critical to the translation of research into the clinical pain management, to increasing the understanding of the contributory mechanisms and factors, and to the development of effective pain management. This chapter focuses on the assessment of pain and sensory status, associated psychosocial factors, and pharmacological and nonpharmacological pain management after CNS injury and disease. Principles and utility of the various types of painrelated assessments and examinations including pain report, pain classification, quantitative sensory testing, and psychological factors are discussed. Finally, both pharmacological and nonpharmacological treatment options for these persistent pain conditions are reviewed and discussed in the context of putative mechanisms

Chronic pain and nonpainful sensations after spinal cord injury: is there a relation?

First, to define the clinical characteristics of nonpainful sensations (NP) that commonly appear after spinal cord injury (SCI); and second, to compare the clinical characteristics of NP and chronic pain (CP) after SCI. Two sets of questions concerning CP and NP were mailed to 330 subjects. Responses from 197 persons experiencing CP as well as NP were analyzed. The most common locations for CP and NP were back and lower extremities. Although the number of areas in which the subjects perceived CP and NP to be located was significantly correlated, a factor analysis showed separate groupings of areas with CP and NP, respectively. Self-reported allodynia or hyperesthesia in the lower extremities, however, was significantly associated with CP in the same areas. The number of descriptive adjectives used for CP and NP was also significantly correlated, as was the perceived intensity of CP versus NP. Additionally, significant correlations were found in onset and temporal pattern of CP and NP. Similarly to CP, NP interfered with sleep, work, and other daily activities, and the patterns of interference due to CP and NP were significantly correlated. While many aspects of the clinical picture of CP and NP are similar after SCI, the CP and spontaneous NP are not necessarily located in the same areas. Although the observed similarities between CP and NP may be based on pathophysiologic mechanisms, the significant relations between the interference patterns suggest that psychosocial mechanisms related to coping are also involved

Aging with a Disability: Physical Impairment, Pain, and Fatigue

This article focuses on the role of pain and fatigue in aging people who have physical impairments and provides a brief summary of definitions, descriptions, and classifications of pain and fatigue; implications of these secondary conditions on the health and functioning; multidisciplinary assessment and treatment options; and critical gaps in knowledge and directions for future research. Central nervous system trauma, diseases of the nervous system, and degenerative muscle diseases often result in significant physical impairments and disability. People who are living and aging with these underlying medical conditions often experience pain and fatigue secondary to their physical impairment that may worsen over time, resulting in increased disability and decreased quality of life. Important areas for future research in persons who have physical impairments include identification of conditions that require age-specific considerations; identification of symptom clusters (eg, pain, fatigue, depression) and how they evolve over time; and development of interdisciplinary treatment protocols

Reliability and validity of quantitative sensory testing in persons with spinal cord injury and neuropathic pain

Quantitative sensory testing (QST) has been used to assess neurological function in various chronic pain patient populations. In the present study, we investigated the ability of QST to reliably characterize somatosensory dysfunction in subjects with spinal cord injury (SCI) and neuropathic pain by measuring mechanical, vibration, and thermal detection and pain thresholds. Test-retest reliability was determined based on data collected from 10 subjects with SCI and neuropathic pain who underwent QST on two occasions approximately 3 weeks apart. The intraclass correlation coefficients for mechanical, vibration, warm, and cool detection thresholds were in the "substantial" range, while thresholds for cold pain and hot pain demonstrated "fair" stability in this sample of patients. To determine the validity of QST in persons with SCI-related neuropathic pain, we evaluated the relationship between somatosensory thresholds and severity of neuropathic pain symptoms with multiple linear regression analysis. Thermal pain threshold was the only QST variable significantly related to the severity of neuropathic pain symptoms. The present study provides preliminary evidence that QST is a reliable and valid adjunct measurement strategy for quantifying the neurological dysfunction associated with neuropathic pain in persons with SCI