Pharmacotherapy options for complex regional pain syndrome

EMG biofeedback combined with rehabilitation training may be the best physical therapy for improving upper limb motor function and relieving pain in patients with the post-stroke shoulder-hand syndrome: A Bayesian network meta-analysis

Background

Post-stroke shoulder-hand syndrome (SHS), although not a life-threatening condition, may be the most distressing and disabling problem for stroke survivors. Thus, it is essential to identify effective treatment strategies. Physical therapy is used as a first-line option for treating SHS; however, it is unclear which treatment option is preferred, which creates confusion in guiding clinical practice. Our study aims to guide clinical treatment by identifying the most effective physical therapy interventions for improving clinical symptoms in patients with post-stroke SHS using Bayesian network meta-analysis.

Methods

We conducted a systematic and comprehensive search of data from randomized controlled trials using physical therapy in patients with SHS from database inception to 1 July 2022. Fugl-Meyer Upper Extremity Motor Function Scale (FMA-UE) and pain visual analog score (VAS) were used as primary and secondary outcome indicators. R (version 4.1.3) and STATA (version 16.0) software were used to analyze the data.

Results

A total of 45 RCTs with 3,379 subjects were included, and the intervention efficacy of 7 physical factor therapies (PFT) combined with rehabilitation training (RT) was explored. Compared with the control group, all the PFT + RT included were of statistical benefit in improving limb motor function and pain relief. Also, our study indicated that EMG biofeedback combined with RT (BFT + RT) [the surface under the cumulative ranking curve (SUCRA) = 96.8%] might be the best choice for patients with post-stroke SHS.

Conclusion

EMG biofeedback combined with rehabilitation training may be the best physical therapy for improving upper limb motor function and relieving pain in patients with post-stroke SHS according to our Bayesian network meta-analysis results. However, the above conclusions need further analysis and validation by more high-quality RCTs.

Systematic review registration

www.crd.york.ac.uk/prospero/, identifier: CRD42022348743.

Intranasal Administration for Pain: Oxytocin and Other Polypeptides

Pain, particularly chronic pain, remains one of the most debilitating and difficult-to-treat conditions in medicine. Chronic pain is difficult to treat, in part because it is associated with plastic changes in the peripheral and central nervous systems. Polypeptides are linear organic polymers that are highly selective molecules for neurotransmitter and other nervous system receptors sites, including those associated with pain and analgesia, and so have tremendous potential in pain therapeutics. However, delivery of polypeptides to the nervous system is largely limited due to rapid degradation within the peripheral circulation as well as the blood–brain barrier. One strategy that has been shown to be successful in nervous system deposition of polypeptides is intranasal (IN) delivery. In this narrative review, we discuss the delivery of polypeptides to the peripheral and central nervous systems following IN administration. We briefly discuss the mechanism of delivery via the nasal–cerebral pathway. We review recent studies that demonstrate that polypeptides such as oxytocin, delivered IN, not only reach key pain-modulating regions in the nervous system but, in doing so, evoke significant analgesic effects. IN administration of polypeptides has tremendous potential to provide a non-invasive, rapid and effective method of delivery to the nervous system for chronic pain treatment and management.

Complex Regional Pain Syndrome Type 1: Diagnosis and Management

Diagnosis of Complex regional pain syndrome (CRPS) is made primarily on a clinical basis, and no specific test is known to confirm or exclude CRPS diagnosis. That is, there aren’t specific diagnostic tools and instrumental tests are made only for identifying an etiology at the basis of the CRPS. Numerous therapeutic methods have been introduced, but none have shown definitive results. When symptoms persist, patients experience permanent impairment and disability. Therefore, early recognition of CRPS, along with proper treatment, is important for minimizing permanent loss of function. As there is no gold standard test for CRPS, several clinical diagnostic criteria have been introduced and applied in various studies. However, to date, no formal or standardized diagnostic criteria for CRPS have been widely accepted. However, the Budapest diagnostic criteria have recently increased in popularity and are frequently used in scientific studies. The goal for management of CRPS is the return of normal limb function. No specific technique has been shown to prevent CRPS following surgery, but avoidance of prolonged immobilization may be important. Therefore, initiating early post-surgical rehabilitation, where possible, is important. A multidisciplinary approach would seem to be optimal, above all things objectives of physical and occupational therapy are fulfilled with combination pharmacotherapy due to provide pain relief to facilitate physical rehabilitation. Future research using large randomized controlled trials should focus on collecting strong evidence for the etiology of CRPS, testing pharmacological effects, and determining appropriate combination treatment strategies.

Type I complex regional pain syndrome

First described by Ambroise Paré in the mid-17th century complex, regional pain syndrome (CRPS) can be defined as an articular and periarticular pain syndrome associated with vasomotor deregulation triggered by various stresses with no relationship between the intensity of the initial injury and severity of the continuing pain. Several names have been given to Type 1 complex regional pain syndrome (CRPS-I): causalgia, reflex sympathetic dystrophy, shoulder-hand syndrome and algodystrophy. The reported incidence of CRPS-I is about 25 per 100,000. Predisposing factors are tobacco consumption and being female (W/M ratio=4). Although all the limbs can be affected, the upper limb is by far the most affected. CRPS-I is a classic complication of distal radius fractures (4-37%) and carpal tunnel surgery (2-4%). Early diagnosis and management are the most important elements of treatment because this syndrome has a long and disabling course. Some of the proposed treatments include NSAIDs, antidepressants and anticonvulsants. The latter, despite their good analgesic effects, do not cure CRPS-I. In select cases, a surgical procedure aiming at removing a nociceptive stimulus can lead to spectacular improvements.

Four treatment strategies for complex regional pain syndrome type 1

Complex regional pain syndrome (CRPS) poses a dilemma for many clinicians due to its unknown etiology and largely unsuccessful treatment modalities. The purpose of this study was to compare the clinical results of 4 treatment modalities for CRPS type 1. A total of 59 patients were divided into 4 groups based on treatment modality: group A, an oral nonsteroidal anti-inflammatory drug (NSAID) (n=10); group B, oral gabapentin (n=12); group C, intravenous (IV) 10% mannitol and steroid (n=11); group D, a combination of IV 20% mannitol and steroid with oral gabapentin (n=26). The patients remained under medical supervision after discharge and were evaluated either once a month or once every 2 months until final follow-up at a mean of 8 months. Patients in group A showed improvement in pain level, finger range of motion, swelling, and grip strength, without statistical significance (P=.076, P=.062, P=.312, and P=.804, respectively). Patients in group B showed significant improvement in pain level (P<.001), and patients in group C showed improvement in pain, finger range of motion, and swelling (P=.127), which rendered functional impairment unchanged. In comparison, patients in group D showed recovery of grip strength and improvement in pain level, finger range of motion, and (P<.001, P=.016, P=.031, and P=.047, respectively). Based on these results, a protocol including a combination of IV 20% mannitol and steroid with oral gabapentin is an acceptable and effective treatment for CRPS type 1.

Stellate ganglion blockade (SGB) for refractory index finger pain - a case report

OBJECTIVE

To identify through case study the presentation and possible pathophysiological cause of complex regional pain syndrome and its preferential response to stellate ganglion blockade.

SETTING

Complex regional pain syndrome can occur in an extremity after minor injury, fracture, surgery, peripheral nerve insult or spontaneously and is characterised by spontaneous pain, changes in skin temperature and colour, oedema, and motor disturbances. Pathophysiology is likely to involve peripheral and central components and neurological and inflammatory elements. There is no consistent approach to treatment with a wide variety of specialists involved. Diagnosis can be difficult, with over-diagnosis resulting from undue emphasis placed upon pain disproportionate to an inciting event despite the absence of other symptoms or under-diagnosed when subtle symptoms are not recognised. The International Association for the Study of Pain supports the use of sympathetic blocks to reduce sympathetic nervous system overactivity and relieve complex regional pain symptoms. Educational reviews promote stellate ganglion blockade as beneficial. Three blocks were given at 8, 10 and 13 months after the initial injury under local anaesthesia and sterile conditions. Physiotherapeutic input was delivered under block conditions to maximise joint and tissue mobility and facilitate restoration of function.

CONCLUSION

This case demonstrates the need for practitioners from all disciplines to be able to identify the clinical characteristics of complex regional pain syndrome to instigate immediate treatment and supports the notion that stellate ganglion blockade is preferable to upper limb intravenous regional anaesthetic block for refractory index finger pain associated with complex regional pain syndrome.

Referral and treatment patterns for complex regional pain syndrome in the Netherlands

BACKGROUND

Patients with complex regional pain syndrome (CRPS) are seen and treated by a variety of physicians. The present study aims to describe referral and treatment patterns for CRPS patients in the Netherlands.

METHODS

Patients, who were selected (1996-2005) from an electronic general practice (GP) database (Integrated Primary Care Information Project), were invited for study participation, involving diagnosis verification (International Association for the Study of Pain criteria) and assessment of referrals and treatment through information retrieved from GP journals, patients' questionnaires, pharmacy dispensing lists and specialist letters if available.

RESULTS

One hundred and two patients were included. Sixty-one percent had presented first at the GP, while 80% subsequently consulted one or more medical specialists, most frequently an anesthetist (55% of the cases) or a specialist in rehabilitation medicine (41%). Over 90% of the patients received oral or topical pharmacotherapy, 45% received intravenous therapy, 89% received non-invasive therapy (i.e. physiotherapy) and 18% received nerve blocks. Analgesics and free radical scavengers were administered early during CRPS, while vasodilating drugs and drugs against neuropathic pain (antidepressants and anti-epileptics) were administered later on. Pharmacotherapy was usually initiated by a medical specialist.

CONCLUSION

The Dutch treatment guidelines, issued in 2006, recommend free radical scavenger prescription (plus physiotherapy) as the initial treatment step for CRPS. Until 2005 only half of the patients received a scavenger within 3 months after disease onset, and the majority presents first at the GP, in particular GPs may be encouraged to initiate treatment with scavengers, while waiting for the results of further specialist consultation.