Deficient muscle activation in patients with Complex Regional Pain Syndrome and abnormal hand postures: An electromyographic evaluation

Peripheral Neuropathic Pain and Pain Related to Complex Regional Pain Syndrome with and without Fixed Dystonia - Efficient Therapeutic Approach with Local Anesthetics

Peripheral Neuropathic Pain (PNP) as well as the Complex Regional Pain Syndrome (CRPS), also known as “Reflex Sympathetic Dystrophy”, or “Sudeck Dystrophy”, all of them have a poor prognosis. The numerous therapeutic offers are rarely accompanied by convincing success over a long duration of time. Even worse is the prognosis of a fixed dystonia which may develop in the extremities of PNP or CRPS patients. In literature a few cases are reported in which the often unbearable pain of those patients with or without a disabling dystonia disappeared immediately after the injection of local anesthetics (LAs) into the scars of a preceding trauma. This review evaluates publications concerning the neuropathological characteristics of fixed dystonia in PNP/CRPS patients and the electrophysiological processes of scar neuromas. The results of these evaluations support the understanding of the therapeutic successes and their immediate results reported above by the injection of LAs into triggering scars. Therapeutic options are discussed.

Evidence already exists for motor system reorganization in CRPS

Complex regional pain syndrome (CRPS) is a disabling condition that is usually preceded by trauma or surgical procedure. Involvement of the motor system is a well-known phenomenon in CRPS, though the pathophysiologic mechanisms of motor system affliction in CRPS are poorly understood. Graded motor imagery (GMI) has been proposed to be one of the therapeutic interventions to help improve pain and other disabling symptoms associated with CRPS, though the benefits noted are modest and inconsistent. The neurophysiological mechanisms implicated in motor imagery are intended to target the aberrant prefrontal and sensorimotor integration areas, which may potentially help restore the aberrant cortical plasticity in CRPS. Detailed well-controlled experiments using insights from the existing body of literature on motor system reorganization in CRPS are required to better understand this complicated disorder. Attempts to gain pathophysiologic insights about complicated disorders like CRPS based on case reports with poorly performed and uncontrolled interventions are misguided.

A Protocol for Evaluation and Rehabilitation of Distal Radius Fractures Using Sensorimotor Input: A Case Series

BACKGROUND

Proprioception and sensorimotor input are used to treat neurological and joint injuries. Following distal radius fractures (DRF) there is a temporary loss of proprioception that should be addressed. We created a protocol for evaluation, and a treatment plan following wrist surgery that is based on proprioceptive and sensorimotor input. We describe a series of patients undergoing surgery for DRF that were evaluated and treated with these protocols.

METHODS

Both evaluation and treatment protocols included comprehensive sensorimotor procedures performed with eyes open and closed. These included Semmes- Weinstein, static and moving 2-point discrimination, vibration, temperature testing, Moberg pick-up- test, stereognosis and proprioception.

RESULTS

A series of twelve patients was evaluated and treated with the protocol following surgical treatment for DRF. Patients demonstrated significant sensorimotor deficits, which improved utilizing the comprehensive sensorimotor treatment protocol.

CONCLUSIONS

Further study is necessary to validate the results of this pilot series. Use of proprioception and sensorimotor input may improve outcomes of rehabilitation following DRF.

Pathological mechanism of musculoskeletal manifestations associated with CRPS type II: an animal study

Patients with complex regional pain syndrome (CRPS) often complain of abnormal sensations beyond the affected body part, but causes of this spread of musculoskeletal manifestations into contiguous areas remain unclear. In addition, immobilization can predispose to the development of CRPS. We examined functional, biochemical, and histological alterations in affected parts, including contiguous zones, using an animal model. Ten-week-old male Wistar rats were assigned to 5 groups: a normal group receiving no treatment, a sham operation group with surgical exploration, an immobilization group with surgical exploration plus internal knee joint immobilization, a surgical neuropathy group prepared by spinal nerve ligation (SNL) of the left L5 nerve root, and a surgical neuropathy+immobilization group with simultaneous SNL and knee joint immobilization. Mechanical allodynia and knee contracture were compared between groups, and tissues were harvested for histological assessments and gene and protein expression analyses. Neither surgical procedures nor immobilization induced detectable mechanical sensitivity. However, the addition of nerve injury resulted in detectable mechanical allodynia, and immobilization not only accelerated hyperalgesia, but also resulted in muscle fibrosis. Nerve growth factor (NGF) and other mediators of neurogenic inflammation were highly expressed not only in denervated muscles, but also in innervated muscles in contiguous areas, suggesting the spread of NGF production beyond the myotome of the injured nerve. Transforming growth factor β was involved in the development of contracture in CRPS. These findings imply that neuroinflammatory components play major roles in the progression and dispersion of both sensory pathologies and pathologies that are exacerbated by immobilization.

Responsiveness to botulinum toxin type A in muscles of complex regional pain patients with tonic dystonia

Tonic dystonia of the limbs in complex regional pain syndrome (CRPS) is associated with considerable disability. Treatment options are scarce. Botulinum toxin (BoNT) is sometimes used, but the effect is often said to be disappointing. However, this notion stems from case reports and clinicians' opinions but has never been formally studied. We therefore investigated responsiveness to BoNT in CRPS patients with tonic dystonia. We injected the extensor digitorum brevis (EDB) muscle with BoNT-A in 17 patients with CRPS and tonic dystonia to compare the response between affected and unaffected legs. We also investigated the right legs of 17 healthy controls. Responsiveness was defined as a decrease of the amplitude of the compound muscle action potential (CMAP) of >20% from baseline 2 weeks after BoNT-A injection. We controlled for a temperature effect on BoNT efficacy by measuring skin temperature hourly directly above the EDB muscle in the first 2 weeks. CMAP amplitude decreased >20% after injection on the affected side in 16 of 17 CRPS patients, similar to the response in unaffected legs (12/13) or legs of controls (17/17). The degree of CMAP reduction was significantly smaller in patients than in controls (56.0 ± 22.3 vs. 70.6 ± 14.6%; p = 0.031). This may be due to a lower physical activity level and a greater difficulty to localize the EDB muscle properly in affected legs. The decrease in CMAP amplitude was not related to skin temperature. Contrary to the prevailing opinion, BoNT-A has a normal, although perhaps slightly lower efficacy in CRPS patients with dystonia.