Pain in the Context of Sensory Deafferentation.

Pain that accompanies deafferentation is one of the most mysterious and misunderstood medical conditions. Prevalence rates for the assorted conditions vary considerably but the most reliable estimates are greater than 50% for strokes involving the somatosensory system, brachial plexus avulsions, spinal cord injury, and limb amputation, with controversy surrounding the mechanistic contributions of deafferentation to ensuing neuropathic pain syndromes. Deafferentation pain has also been described for loss of other body parts (e.g., eyes and breasts) and may contribute to between 10% and upwards of 30% of neuropathic symptoms in peripheral neuropathies. There is no pathognomonic test or sign to identify deafferentation pain, and part of the controversy surrounding it stems from the prodigious challenges in differentiating cause and effect. For example, it is unknown whether cortical reorganization causes pain or is a byproduct of pathoanatomical changes accompanying injury, including pain. Similarly, ascertaining whether deafferentation contributes to neuropathic pain, or whether concomitant injury to nerve fibers transmitting pain and touch sensation leads to a deafferentation-like phenotype can be clinically difficult, although a detailed neurologic examination, functional imaging, and psychophysical tests may provide clues. Due in part to the concurrent morbidities, the physical, psychologic, and by extension socioeconomic costs of disorders associated with deafferentation are higher than for other chronic pain conditions. Treatment is symptom-based, with evidence supporting first-line antineuropathic medications such as gabapentinoids and antidepressants. Studies examining noninvasive neuromodulation and virtual reality have yielded mixed results.

A Pilot Study of Autonomic Function Screening Tests for Differentiating Complex Regional Pain Syndrome Type II and Traumatic Neuropathic Pain.

Background and Objectives: One of the most challenging tasks in a clinical setting is to differentiate between complex regional pain syndrome (CRPS) type II and traumatic neuropathic pain (NeP). CRPS is characterized by several dysautonomic manifestations, such as edema, hyper/hypohidrosis, skin color change, and tachycardia. This study compared the outcomes of autonomic function screening tests in patients with CRPS type II and traumatic NeP for diagnostic differentiation. Materials and Methods: CRPS type II was diagnosed according to the Budapest research criteria, while NeP was diagnosed according to the updated grading system suggested by the International Association for the Study of Pain Special Interest Group on Neuropathic Pain in 2016. Twenty patients with CRPS type II and twenty-five with traumatic NeP were investigated. Results: Twelve patients with CRPS type II presented abnormal results for the quantitative sudomotor axon reflex test (QSART). Abnormal QSART results were more common in the CRPS type II group. Conclusions: Analysis of QSART combined with other ancillary tests can help in the differential diagnosis of CRPS type II and traumatic NeP if factors influencing abnormal QSART are sufficiently controlled.

Gamma Knife radiosurgery for the treatment of cluster headache: a systematic review.

Cluster headache (CH) is a severe trigeminal autonomic cephalalgia that, when refractory to medical treatment, can be treated with Gamma Knife radiosurgery (GKRS). The outcomes of studies investigating GKRS for CH in the literature are inconsistent, and the ideal target and treatment parameters remain unclear. The aim of this systematic review is to evaluate the safety and the efficacy, both short and long term, of GKRS for the treatment of drug-resistant CH. A systematic review of the literature was performed to identify all clinical articles discussing GKRS for the treatment of CH. The literature review revealed 5 studies describing outcomes of GKRS for the treatment of CH for a total of 52 patients (48 included in the outcome analysis). The trigeminal nerve, the sphenopalatine ganglion, and a combination of both were treated in 34, 1, and 13 patients. The individual studies demonstrated initial meaningful pain reduction in 60-100% of patients, with an aggregate initial meaningful pain reduction in 37 patients (77%). This effect persisted in 20 patients (42%) at last follow-up. Trigeminal sensory disturbances were observed in 28 patients (58%) and deafferentation pain in 3 patients (6%). Information related to GKRS for CH are limited to few small open-label studies using heterogeneous operative techniques. In this setting, short-term pain reduction rates are high, whereas the long-term results are controversial. GKRS targeted on the trigeminal nerve or sphenopalatine ganglion is associated to a frequent risk of trigeminal disturbances and possibly deafferentation pain.

Causalgia: a military pain syndrome.

Causalgia, officially known as complex regional pain syndrome type II, is a pain syndrome characterized by severe burning pain, motor and sensory dysfunction, and changes in skin color and temperature sensation distal to an injured peripheral nerve. The pain syndrome primarily tends to affect combat soldiers after they sustain wartime injuries from blasts and gunshots. Here, the authors provide a historical narrative that showcases the critical contributions of military physicians to our understanding of causalgia and to the field of peripheral nerve neurosurgery as a whole.

[Complex regional pain syndrome-An update]. / Komplexes regionales Schmerzsyndrom ­ ein Update.

Complex regional pain syndrome (CRPS) is a pain disorder that develops in the hands or feet after injury. Currently, two types are differentiated, CRPS I without and CRPS II with nerve lesions as well as with either an initially warm or an initially cold subtype, depending on the clinical symptoms. After trauma a certain amount of inflammatory reaction is considered physiological. In acute CRPS this inflammation persists for months and is maintained by diverse inflammatory mediators in peripheral tissue and in blood. This persisting inflammation leads to a sensitization of the nociceptive system, causes somatic cells to proliferate and gives rise to a disrupted endothelial function. The treatment concept aims to antagonize the pathophysiologic components and includes anti-inflammatory and analgetic treatment, mobilization and restoration of the sensorimotor function of the affected limb.

Bone marrow mesenchymal stem cells upregulate PI3K/AKT pathway and down-regulate NF-κB pathway by secreting glial cell-derived neurotrophic factors to regulate microglial polarization and alleviate deafferentation pain in rats.

Deafferentation pain (DP), a typical neuropathic pain, occurs due to peripheral or central sensory nerve injury, which causes abnormal discharge of the upstream neurons or C fibers. Current treatment methods for DP have multiple side effects. Bone marrow mesenchymal stem cells (BMSC) have been used to treat neuropathic pain because of their ability to regulate neuroinflammation. Glial cell-derived neurotrophic factor (GDNF) is a neurotrophic mediator that exerts neuroprotective effects in neurological diseases. In this study, we investigated whether DP could be alleviated by BMSCs and the underlying mechanism. In vitro study, microglia was stimulated by lipopolysaccharide and then co-cultured with BMSC, GDNF or siRNA GDNF-BMSC. In vivo study, BMSC or siRNA GDNF-BMSC was transplanted intramedullarily on the 21st day after DP surgery. The expression of inflammatory-related factors were detected by RT-PCR and ELISA, RT-PCR,flow cytometry and immunofluorescence staining were performed to detect the expression of microglial surface markers, and Western blot was used to detect the expression levels of p-NF-kb, pPI3K, and pAKT. The pain-related behavioral changes were detected 7 days after transplantation. ELISA and RT-PCR results showed that the production of inflammatory cytokines in lipopolysaccharide-stimulated microglia and DP model plasma was downregulated, while anti-inflammatory mediators were upregulated significantly following pretreatment with BMSCs or GDNF. Flow cytometry, immunofluorescence staining, and RT-PCR results showed that BMSCs inhibited the microglial M1 phenotype and promoted the M2 phenotype by secreting GDNF. Furthermore, modulation functions of BMSCs involve inhibiting NF-κB while promoting PI3K /AKT signaling pathway activation. We found that our in vivo DP model was completely deafferent and BMSC administration clearly alleviated symptoms of DP. This function was also, at least partly, achieved by GDNF. The present studies demonstrate that BMSC can inhibit neuroinflammation by transforming microglial destructive M1 phenotype into regenerative M2 phenotype, and thus alleviate DP,likely by suppressing the NF-κB signaling pathway while promoting the PI3K/AKT signaling pathway activation through producing GDNF. The present findings are in support of the potential therapeutic application of BMSCs and the pharmaceutical application of GDNF for DP.

Neuromodulation of the Dorsal Root Ganglion for Chronic Postsurgical Pain.

OBJECTIVE: The objective of this study is to review the available evidence for dorsal root ganglion (DRG) stimulation for the treatment of complex regional pain syndrome type II (CRPS II; peripheral causalgia) associated with chronic neuropathic postsurgical pain (NPP). DESIGN: Available literature was identified through a search of the US National Library of Medicine's Medline database, PubMed.gov. References from published articles also were reviewed for relevant citations. RESULTS: The data published to date support the use of DRG stimulation to treat chronic NPP of the groin, knee, and foot. NPP following procedures such as thoracotomy, hernia surgery, and knee replacement surgery were identified as some of the conditions for which DRG stimulation is likely to be effective. CONCLUSION: DRG stimulation is known to be an effective treatment for focal neuropathic pain. Currently, NPP of the foot, groin, and knee all appear to be the conditions with the most clinical experience, backed by a limited but growing body of evidence. However, prospective studies lag behind real-world clinical experience and are needed to confirm these findings.

Comparison of Paresthesia Coverage of Patient's Pain: Dorsal Root Ganglion vs. Spinal Cord Stimulation. An ACCURATE Study Sub-Analysis.

OBJECTIVES: This was a sub-analysis of the ACCURATE clinical trial that evaluated the accuracy and necessity of targeting paresthesia coverage of painful areas with dorsal root ganglion (DRG) stimulation vs. tonic spinal cord stimulation (SCS). MATERIALS AND METHODS: On diagrams of the torso and lower limbs, subjects marked where they felt pain at baseline and paresthesias at three months postimplant. Seventy-five subjects (41 DRG and 34 SCS) with diagrams of sufficient quality were scanned, digitized, and included in this analysis. Subject completed diagrams were digitized and superimposed with a grid of 1398 squares. Quantification of the percentage of bodily areas affected by pain and stimulation induced paresthesias was performed. RESULTS: The percent of painful areas covered by paresthesia was significantly lower for DRG subjects than for SCS subjects (13% vs. 28% of the painful regions, p < 0.05), possibly because significantly more DRG subjects felt no paresthesia during stimulation when compared to SCS subjects (13/41 DRG vs. 3/34 SCS) (p < 0.05). The amount of paresthesia produced outside the painful areas (unrequired paresthesia) was significantly lower in DRG subjects than that of SCS subjects. On average, the percent of unrequired paresthesia was only 20% of the subjects' total painful body surface area in the DRG group compared to 210% in the SCS group (p < 0.01). CONCLUSIONS: The results of this ACCURATE study sub-analysis show that DRG stimulation produces paresthesias, on average, that are less frequent, less intense, with a smaller footprint on the body and less dependent on positional changes.

Dorsal Root Ganglion Stimulation Is Paresthesia-Independent: A Retrospective Study.

INTRODUCTION: Neuromodulation is an important tool for achieving pain relief in otherwise-intractable neuropathic pain conditions. Dorsal root ganglion (DRG) stimulation, in which primary sensory neurons are stimulated prior to their entry into the spinal canal, provides treatment with high levels of dermatomal specificity and can provide advantages compared to conventional spinal cord stimulation. Although DRG stimulation can produce perceptible paresthesias, many patients operate their systems at subthreshold amplitudes that do not elicit this sensation. Pain relief both with and without paresthesia was investigated in this retrospective analysis. MATERIALS AND METHODS: A retrospective review of all qualifying permanent DRG stimulation systems at a single center over more than a three-year period was completed. Pain (0-10 numeric rating scale) was assessed at baseline, at the end of the trial, and after three, six, and twelve months of treatment. Patients were categorized based on their usage of the stimulator at amplitudes that either did or did not produce paresthesias. RESULTS: Of the 39 patients, 34 (87%) reported having no-paresthesias at any of the follow-up visits. Average pain relief was 73.9% after the trial period and 63.1% after 12 months of treatment. The responder rate (50% or better pain relief) after three months of treatment was more than 80%. Exploratory subgroup analyses showed that similar degrees of pain relief were achieved in numerous body regions and with various pain etiologies. The five patients who reported paresthesias during treatment had pain relief similar to those of the group that did not experience paresthesias. DISCUSSION: Clinically significant and sustained pain relief over more than a period of 12 months was achieved with DRG stimulation programmed at amplitudes below the perceptual level. Thus, the reported analgesia was paresthesia-independent. That good clinical outcomes were observed independent of the generation of paresthesia in DRG stimulation suggests several mechanisms of action, including the inhibition of supraspinal regions involved in somatic paresthesia sensation. The retrospective results presented here posit that future prospective study of DRG stimulation delivered at below the threshold of perceptible paresthesias is warranted.

Motor Cortex Stimulation for Deafferentation Pain.

PURPOSE OF REVIEW: Since the early 1990s, motor cortex stimulation (MCS) has been a unique treatment modality for patients with drug-resistant deafferentation pain. While underpowered studies and case reports have limited definitive, data-driven analysis of MCS in the past, recent research has brought new clarity to the MCS literature and has helped identify appropriate indications for MCS and its long-term efficacy. RECENT FINDINGS: In this review, new research in MCS, repetitive transcranial magnetic stimulation (rTMS), and transcranial direct current stimulation (tDCS) are analyzed and compared with historical landmark papers. Currently, MCS is effective in providing relief to 40-64% of patients, with decreasing analgesic effect over time addressed by altering stimulation settings. rTMS and tDCS, two historic, non-invasive stimulation techniques, are providing new alternatives for the treatment of deafferentation pain, with rTMS finding utility in identifying MCS responders. Future advances in electrode arrays, neuro-navigation, and high-definition tDCS hold promise in providing pain relief to growing numbers of patients. Deafferentation pain is severe, disabling, and remains a challenge for patients and providers alike. Over the last several years, the MCS literature has been revitalized with studies and meta-analyses demonstrating MCS effectiveness and providing guidance in identifying responders. At the same time, rTMS and tDCS, two time-honored non-invasive stimulation techniques, are finding new utility in managing deafferentation pain and identifying good MCS candidates. As the number of potential therapies grow, the clinician's role is shifting to personalizing treatment to the unique pain of each patient. With new treatment modalities, this form of personalized medicine is more possible than ever before.

LETM presented with causalgia and ensued by sudden death.

BACKGROUND: Longitudinally Extensive Transverse Myelitis LETM is a specific pattern of myelitis wherein at least three continuous vertebral segments are involved. Characteristically, it is a defining feature of neuromyelitis optica NMO. However, it is described in many other etiologies. CASE PRESENTATION: We present a case of 60 year old male who presented with symptoms and signs of regional sympathetic dystrophy RSD followed by symptoms of myelitis. Spinal cord MRI revealed cervical LETM extending to the brainstem. In spite of serological negativity, treatment of suspected neuromyelitis optica spectrum disorder NMOSD was initiated and resulted in symptom relief. Meanwhile, sudden death occurred and autonomic dysreflexia was the main culprit. CONCLUSIONS: This case suggests that RSD could be the mere primary presentation of LETM, discusses the differential diagnoses of LETM in elderly patients, and suggests the possible risk of autonomic dysreflexia in such patients.

The pre-amputation pain and the postoperative deafferentation are the risk factors of phantom limb pain: a clinical survey in a sample of Chinese population.

BACKGROUND: To provide an overview of phantom limb pain (PLP) in China. This includes the prevalence of PLP and possible risk factors. METHODS: In a retrospective study, telephone interviews were conducted with 391 amputation patients who underwent extremity amputations at a tertiary hospital in China. RESULTS: PLP was found in 29% of the amputees. Pre-amputation pain (OR = 10.4, P = 0.002) and postoperative analgesia (OR = 4.9, P = 0.008) were identified as high-risk factors for PLP. 82.1% of PLP patients experienced pre-amputation pain. The average pain intensity of PLP was 5.1 ± 2.2, with 31.9% having severe intensity. The effects of PLP on the quality of the PLP patients were as follows: 7.8% of the patients had to limit their daily life and 29.0% of the patients had to limit their social activities. 17.3 and 25.7% of patients experienced depression and sleeping disorder respectively, while 18.9% had loss of interest and even 16.1% of PLP patients had attempted suicide. No effective treatments were found in 78.9% of these patients. CONCLUSIONS: PLP has markedly affected the lives of patients. Pre-amputation pain and postoperative epidural analgesia might be risk factors for the phantom limb pain after amputation. Prevention of pre-amputation pain and sudden post-amputation deafferentation should be recommended to the amputees.

Local anaesthetic sympathetic blockade for complex regional pain syndrome.

BACKGROUND: This review is an update of a previously published review in the Cochrane Database of Systematic Reviews, 2005, Issue 4 (and last updated in the Cochrane Database of Systematic Reviews, 2013 issue 8), on local anaesthetic blockade (LASB) of the sympathetic chain to treat people with complex regional pain syndrome (CRPS). OBJECTIVES: To assess the efficacy of LASB for the treatment of pain in CRPS and to evaluate the incidence of adverse effects of the procedure. SEARCH METHODS: For this update we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2015, Issue 9), MEDLINE (Ovid), EMBASE (Ovid), LILACS (Birme), conference abstracts of the World Congresses of the International Association for the Study of Pain, and various clinical trial registers up to September 2015. We also searched bibliographies from retrieved articles for additional studies. SELECTION CRITERIA: We considered randomised controlled trials (RCTs) that evaluated the effect of sympathetic blockade with local anaesthetics in children or adults with CRPS compared to placebo, no treatment, or alternative treatments. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. The outcomes of interest were reduction in pain intensity, the proportion who achieved moderate or substantial pain relief, the duration of pain relief, and the presence of adverse effects in each treatment arm. We assessed the evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation) and created a 'Summary of findings' table. MAIN RESULTS: We included an additional four studies (N = 154) in this update. For this update, we excluded studies that did not follow up patients for more than 48 hours. As a result, we excluded four studies from the previous review in this update. Overall we included 12 studies (N = 461), all of which we judged to be at high or unclear risk of bias. Overall, the quality of evidence was low to very low, downgraded due to limitations, inconsistency, imprecision, indirectness, or a combination of these.Two small studies compared LASB to placebo/sham (N = 32). They did not demonstrate significant short-term benefit for LASB for pain intensity (moderate quality evidence).One small study (N = 36) at high risk of bias compared thoracic sympathetic block with corticosteroid and local anaesthetic versus injection of the same agents into the subcutaneous space, reporting statistically significant and clinically important differences in pain intensity at one-year follow-up but not at short term follow-up (very low quality evidence).Of two studies that investigated LASB as an addition to rehabilitation treatment, the only study that reported pain outcomes demonstrated no additional benefit from LASB (very low quality evidence).Eight small randomised studies compared sympathetic blockade to various other active interventions. Most studies found no difference in pain outcomes between sympathetic block versus other active treatments (low to very low quality evidence).One small study compared ultrasound-guided LASB with non-guided LASB and found no clinically important difference in pain outcomes (very low quality evidence).Six studies reported adverse events, all with minor effects reported. AUTHORS' CONCLUSIONS: This update's results are similar to the previous versions of this systematic review, and the main conclusions are unchanged. There remains a scarcity of published evidence and a lack of high quality evidence to support or refute the use of local anaesthetic sympathetic blockade for CRPS. From the existing evidence, it is not possible to draw firm conclusions regarding the efficacy or safety of this intervention, but the limited data available do not suggest that LASB is effective for reducing pain in CRPS.

Steroid atrophy scarring treated with fat grafting in a patient with complex regional pain syndrome: A case report.

Subcutaneous atrophy is a known complication of steroid injections. Excellent results with fat grafting for the treatment of steroid atrophy have been documented. However, the benefit of treating steroid-induced subcutaneous atrophy in an extremity diagnosed with complex regional pain syndrome (CRPS) has not been described. CRPS, known formerly as reflex sympathetic dystrophy or RSD, causalgia, or reflex neurovascular dystrophy, is a severe, progressive musculoskeletal pain syndrome characterized by pain which is disproportionate to the severity of the inciting event, edema, or skin changes. Common treatment modalities include pharmacotherapy, physical therapy, and nerve blocks-each therapy producing varying results. We present a literature review of CRPS and the case of a 15-year-old female who developed CRPS of the left lower leg after arthroscopic debridement with retrograde drilling of an osteochondral lesion. Steroid atrophy of the involved area following a saphenous nerve block complicated the patient's treatment course. The area of atrophy was treated with autologous fat grafting. Following the adipose injection procedure, the patient experienced almost complete resolution of her CPRS-associated pain symptoms, along with improved cosmetic appearance of the area.

[Complex regional pain syndrome in nerve root compression and after spinal surgery]. / Komplexes regionales Schmerzsyndrom bei Nervenwurzelkompression und nach Wirbelsäulenoperation.

Complex regional pain syndrome (CRPS) is an extremely painful and partially disabling disease. It often occurs secondary to trauma, but also spontaneously. The emergence of CRPS has been reported following nerve root compression and/or spinal surgery, but its incidence is unknown. In this article, the present knowledge about the incidence of CRPS in the context of nerve root compression and spine surgery is reviewed and therapeutic and diagnostic consequences are discussed.

A Novel Compound Analgesic Cream (Ketamine, Pentoxifylline, Clonidine, DMSO) for Complex Regional Pain Syndrome Patients.

BACKGROUND: Evidence suggests that complex regional pain syndrome (CRPS) is a manifestation of microvascular dysfunction. Topical combinations of α2-adrenergic receptor agonists or nitric oxide donors with phosphodiesterase or phosphatidic acid inhibitors formulated to treat microvascular dysfunction have been shown to reduce allodynia in a rat model of CRPS-I. Driven by these findings, we assessed the outcomes of CRPS patients treated with a compound analgesic cream (CAC) consisting of ketamine 10%, pentoxifylline 6%, clonidine 0.2%, and dimethyl sulfoxide 6% to 10%. METHODS: An audit was conducted on 13 CRPS patients who trialed the CAC. A detailed report was compiled for each patient which comprised baseline characteristics, including CRPS description, previous treatments, and pain scores (numerical pain rating scale; 0 to 10). Recorded outcomes consisted of pain scores, descriptive outcomes, and concurrent medications/treatments, for which basic analysis was performed to determine the effectiveness of the CAC. Case reports are presented for 3 patients with varying outcomes. RESULTS: Nine patients (69%) reported pain/symptom reduction (4.4 ± 2.1 vs. 6.3 ± 1.9) with use of the CAC. Six patients reported sustained benefits after 2 months of CAC use, and 2 patients reported complete resolution of pain/symptoms: one had early CRPS-I and the other received a partial CRPS diagnosis. An otherwise medication refractory and intolerant patient found partial benefit with the CAC. CONCLUSIONS: These results demonstrate promise for this topical combination as a useful treatment in multimodal therapy for patients with CRPS, with the potential to resolve pain/symptoms in early CRPS patients.

Phantom pain in a patient with brachial plexus avulsion injury.

OBJECTIVE: Phantom limb pain is a painful sensation perceived in the absent limb following surgical or traumatic amputation. Phantom limb sensations, which are nonpainful, occur in nearly all amputees. Deafferentation can also produce similar symptoms. Here we report the presence of phantom pain in a deafferented limb. DESIGN: Case report. SETTING: Hospital-based outpatient clinic. PATIENT: A 65-year-old man was referred to the pain clinic for management of upper extremity pain secondary to brachial plexus avulsion (BPA) following a motor vehicle accident. Initially he noticed a feeling of growing and shrinking of his arm. Following this, the pain started gradually from his elbow extending to his fingertips covering all dermatomes. He described the pain as continuous, severe, and sharp. He also described the arm as being separate from his existing insensate arm and felt as though the fist was closed with the thumb pointing out. On physical examination, he had no sensation to fine touch or pressure below the elbow. There were no consistent areas of allodynia. He had diffuse muscle wasting in all the muscle groups of his left upper extremity, besides winging of the scapula. Electrodiagnostic studies showed a left brachial plexopathy consistent with multilevel nerve root avulsion sparing the dorsal rami. CONCLUSION: This is a report of phantom limb sensations and phantom pain following BPA in an intact but flaccid and insensate limb.

[Complex regional pain syndrome in a patient with acute drug poisoning: a case report].

We report a case with transition to complex regional pain syndrome (CRPS) caused by nerve injury associated with crush syndrome. The diagnosis was delayed because of coma due to acute drug poisoning. A 44-year-old man had attempted suicide by taking massive amounts of psychotropic drugs 2 days earlier and was transported to our hospital by ambulance. His arms had been compressed due to the prolonged (2 days) consciousness disturbance, and he experienced non-traumatic crush syndrome and rhabdomyolysis. Acute renal failure was prevented with massive infusion and hemofiltration. However, he experienced muscle and nerve injury at the compressed area, which presumably led to CRPS. In cases of suspected crush syndrome associated with acute drug poisoning, it is also important to recognize the possibility of developing CRPS.

Type II complex regional pain syndrome of the hand resulting from repeated arterial punctures during transradial coronary intervention.

Coronary catheterization using a transradial approach has become a common procedure, as the risks of local complications are low and this procedure affords relatively expeditious postprocedural patient mobilization. Access site complications--such as radial artery spasm, hematoma, and compartment syndrome--have been reported in the literature; however, cases of complex regional pain syndrome (CRPS) of the hand related to the procedure are extremely rare. We describe a case of type II CRPS affecting the hand after a transradial coronary intervention that was complicated by repeated periprocedural arterial punctures. In this case, a 55-year-old woman underwent a percutaneous coronary intervention for the treatment of unstable angina. After successful completion of the procedure, the patient complained of severe pain along the median and radial nerve distributions and resulting disability of the right hand. Although subsequent duplex sonography showed no abnormalities, a nerve conduction study uncovered injury to multiple nerves on the right. A diagnosis of type II CRPS was then made and the patient was treated with a nerve block as well as multiple medical modalities. This case demonstrates a very unusual complication resulting from the transradial approach to percutaneous coronary intervention.

Local anaesthetic sympathetic blockade for complex regional pain syndrome.

BACKGROUND: This is an update of the original Cochrane review published in The Cochrane Library, 2005, Issue 4, on local anaesthetic blockade (LASB) of the sympathetic chain used to treat complex regional pain syndrome (CRPS). OBJECTIVES: To assess the efficacy of LASB for the treatment of pain in CRPS and to evaluate the incidence of adverse effects of the procedure. SEARCH METHODS: We updated searches of the Cochrane Pain, Palliative and Supportive Care Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL) on the Cochrane Library (Issue 11 of 12, 2012), MEDLINE (1966 to 22/11/12), EMBASE (1974 to 22/11/12), LILACS (1982 to 22/11/12), conference abstracts of the World Congresses of the International Association for the Study of Pain (1995 to 2010), and various clinical trial registers (inception to 2012). We also searched bibliographies from retrieved articles for additional studies. SELECTION CRITERIA: We considered for inclusion randomised controlled trials (RCTs) that evaluated the effect of sympathetic blockade with local anaesthetics in children or adults with CRPS. DATA COLLECTION AND ANALYSIS: The outcomes of interest were reduction in pain intensity levels, the proportion who achieved moderate or substantial pain relief, the duration of pain relief, and the presence of adverse effects in each treatment arm. MAIN RESULTS: We included an additional 10 studies (combined n = 363) in this update. Overall we include 12 studies (combined n = 386). All included studies were assessed to be at high or unclear risk of bias.Three small studies compared LASB to placebo/sham. We were able to pool the results from two of these trials (intervention n = 23). Pooling did not demonstrate significant short-term benefit for LASB (in terms of the risk of a 50% reduction of pain scores).Of two studies that investigated LASB as an addition to rehabilitation treatment, the only study that reported pain outcomes demonstrated no additional benefit from LASB.Eight small randomised studies compared sympathetic blockade to another active intervention. Most studies found no difference in pain outcomes between sympathetic block and other active treatments.Only five studies reported adverse effects, all with minor effects reported. AUTHORS' CONCLUSIONS: This update has found similar results to the original systematic review. There remains a scarcity of published evidence to support the use of local anaesthetic sympathetic blockade for CRPS. From the existing evidence it is not possible to draw firm conclusions regarding the efficacy or safety of this intervention but the limited data available do not suggest that LASB is effective for reducing pain in CRPS.