A selection of papers to peruse:
Predictors of Pain Relieving Response to Sympathetic Blockade in Complex Regional Pain Syndrome Type 1
Anesthesiology: January 2012 – Volume 116 – Issue 1 – p 113–121
doi: 10.1097/ALN.0b013e31823da45f Pain Medicine
van Eijs, Frank M.D.*; Geurts, José M.Sc.†; van Kleef, Maarten M.D., Ph.D.‡; Faber, Catharina G. M.D., Ph.D.§; Perez, Roberto S. Ph.D.‖; Kessels, Alfons G.H. M.D., M.Sc.#; Van Zundert, Jan M.D., Ph.D.**
Background: Sympathetic blockade with local anesthetics is used frequently in the management of complex regional pain syndrome type 1(CRPS-1), with variable degrees of success in pain relief. The current study investigated which signs or symptoms of CRPS-1 could be predictive of outcome. The incidence of side effects and complications of sympathetic blockade also were determined prospectively.
Methods: A prospective observational study was done of 49 patients with CRPS-1 in one extremity only and for less than 1-yr duration who had severe pain and persistent functional impairment with no response to standard treatment with medication and physical therapy.
Results: Fifteen (31%) patients had good or moderate response. The response rate was not different in patient groups with cold or warm type CRPS-1 or in those with more or less than 1.5°C differential increase in skin temperature after sympathetic blockade. Allodynia and hypoesthesia were negative predictors for treatment success in CRPS-1. There were no symptoms or signs of CRPS-1 that positively predicted treatment success. A majority of patients (84%) experienced transient side effects such as headache, dysphagia, increased pain, backache, nausea, blurred vision, groin pain, hoarseness, and hematoma at the puncture site. No major complications were reported.
Conclusions: The presence of allodynia and hypoesthesia are negative predictors for treatment success. The selection of sympathetic blockade as treatment for CRPS-1 should be balanced carefully between potential success and side effect ratio. The procedure is as likely to cause a transient increase in pain as a decrease in pain. Patients should be informed accordingly.
Motor control in complex regional pain syndrome: A kinematic analysis
- J.C.M. Schildera, , ,
- A.C. Schoutenb, c,
- R.S.G.M. Perezd,
- F.J.P.M. Huygene,
- A. Dahanf,
- L.P.J.J. Noldusg,
- J.J. van Hiltena,
- J. Marinusa
This study evaluated movement velocity, frequency, and amplitude, as well as the number of arrests in three different subject groups, by kinematic analysis of repetitive movements during a finger tapping (FT) task. The most affected hands of 80 patients with complex regional pain syndrome (CRPS) were compared with the most affected hands of 60 patients with Parkinson disease (PD) as well as the nondominant hands of 75 healthy control (HC) subjects. Fifteen seconds of FT with thumb and index finger were recorded by a 60-Hz camera, which allowed the whole movement cycle to be evaluated and the above mentioned movement parameters to be calculated. We found that CRPS patients were slower and tapped with more arrests than the two other groups. Moreover, in comparison with the hands of the HC subjects, the unaffected hands of the CRPS patients were also impaired in these domains. Impairment was not related to pain. Dystonic CRPS patients performed less well than CRPS patients without dystonia. In conclusion, this study shows that voluntary motor control in CRPS patients is impaired at both the affected as well as the unaffected side, pointing at involvement of central motor processing circuits.
Psychological factors associated with self-perceived pain-related disability among individuals diagnosed with complex regional pain syndrome
by Mann, Jeffrey C., Psy.D., ADLER SCHOOL OF PROFESSIONAL PSYCHOLOGY, 2010, 107 pages; 3452691
Over the last several decades the importance of psychological factors in understanding pain-related disability has grown tremendously. Research has explored many psychological constructs and their relationship to pain related disability with several constructs emerging as clinically significant. The research conducted to date has predominantly focused on individuals with conditions such as low-back, arthritis, or other forms of musculoskeletal pain. To date, there is no research examining the predominant psychological constructs with a population of individuals diagnosed with Complex Regional Pain Syndrome (CRPS). This study had two primary purposes: (a) To examine the relationship between pain catastrophizing, pain helplessness, active coping, passive coping and self-perceived, pain-related disability, (b) to determine the amount of variance in self-perceived, pain-related disability accounted for by pain catastrophizing, pain helplessness, active coping, and passive coping. The research sample included 102 individuals diagnosed with CRPS being treated at a pain clinic. The instruments used to measure the independent variables were: Pain Helplessness Index (PHI), Pain Catastrophizing Scale (PCS), and the Coping Strategies Questionnaire (CSQ). The dependent variable was measured with the Perceived Disability Scale (PDS). Correlation analysis indicated that pain catastrophizing, pain helplessness, and passive coping are all positively correlated with self-perceived, pain-related disability. Multiple regression results indicated that pain catastrophizing, and pain helplessness account for 15.3% of the variance in self-perceived, pain-related disability. Active coping and passive coping did not account for a statistically significant portion of the variance. The findings of this study demonstrate the importance of pain catastrophizing and pain helplessness when treating individuals diagnosed with CRPS and raises doubt about the utility of active coping and the detriment of passive coping. Further investigation is needed to determine the efficacy of interventions focused on modifying pain catastrophizing and pain helplessness as a indirect method of decreasing self-perceived disability.
Mast Cells: Source of Inflammation in Complex Regional Pain Syndrome?
Targeting Cortical Representations in the Treatment of Chronic Pain: A Review
- G. Lorimer Moseley
- Herta Flor
Recent neuroscientific evidence has confirmed the important role of cognitive and behavioral factors in the development and treatment of chronic pain. Neuropathic and musculoskeletal pain are associated with substantial reorganization of the primary somatosensory and motor cortices as well as regions such as the anterior cingulate cortex and insula. What is more, in patients with chronic low back pain and fibromyalgia, the amount of reorganizational change increases with chronicity; in phantom limb pain and other neuropathic pain syndromes, cortical reorganization correlates with the magnitude of pain. These findings have implications for both our understanding of chronic pain and its prevention and treatment. For example, central alterations may be viewed as pain memories that modulate the processing of both noxious and nonnoxious input to the somatosensory system and outputs of the motor and other response systems. The cortical plasticity that is clearly important in chronic pain states also offers potential targets for rehabilitation. The authors review the cortical changes that are associated with chronic pain and the therapeutic approaches that have been shown to normalize representational changes and decrease pain and discuss future directions to train the brain to reduce chronic pain.
RS – out of these papers this is the one that I am most interested in reading. A number of the techniques that I use in the clinic for CRPS are targeting the changes in the brain, including Graded Motor Imagery, 2-point discrimination training, sensorimotor integration and mindfulness. We are both obliged and wise to consider why is it that the brain continues to protect a body part(s) and how has this happened? Herta Flor talks about learning and memory in pain and the conditioning process. Reinforcements for particular beliefs and behaviours can start early after an injury or initiation of a pain state. In these stages we must seek to prevent pathological beliefs developing by using focused education, promote useful behaviours that are reinforced and set goals that sit alongside processes of healing and recovery.