Prism Adaptation Treatment Not Shown Effective for Upper-Limb CRPS
Although initial evidence suggested that people with complex regional pain syndrome (CRPS) have reduced attention to the affected side of their body and the surrounding space, which might be related to pain and other clinical symptoms, 3 previous unblinded, uncontrolled studies showed pain relief after treatment with prism adaptation (PA), an intervention that has been used to counter lateralized attention bias in brain-lesioned patients.
In this study, the authors used a robust test of the effectiveness of PA for CRPS. They conducted a double-blind randomized controlled trial of PA for unilateral upper-limb CRPS-I in 49 adults with CRPS randomized to undergo 2 weeks of twice-daily home-based PA treatment (n = 23) or sham treatment (n = 26).
Outcomes were assessed 4 weeks before, immediately before and after treatment, and at 4 weeks. Long-term follow-ups were conducted at 3 and 6 months, examining the effects of both treatments on current pain intensity and the CRPS symptom severity score (primary outcomes), and sensory, motor, and autonomic functions, self-reported psychological functioning, and experimentally tested neuropsychological functions (secondary outcomes).
The researchers found no evidence that primary or secondary outcomes differed between PA and sham treatment groups when tested at either time point after treatment. Overall, CRPS severity significantly decreased over time for both groups. The findings do not support the efficacy of PA treatment for relieving upper-limb CRPS-I.
This trial was prospectively registered (ISRCTN46828292). (See Halicka M, Vitterso AD, McCullough H, et al. Prism adaptation treatment for upper-limb complex regional pain syndrome: a double-blind randomized controlled trial. Pain. 2021;162(2):471-489. doi:10.1097/j.pain.0000000000002053.)
Understanding Prosthesis Ownership and the Relationship With Phantom Limb Pain
Recent research on body perception in amputees suggests that prosthesis ownership, defined as the extent to which a prosthesis is experienced as being part of the body rather than an artificial device foreign to the body, might interact with phantom limb pain (PLP).
Survey data from 2383 unilateral prosthesis-using upper-limb or lower-limb amputees were used to perform regression analyses to determine the relationship between prosthesis ownership and PLP. The authors also examined the role of prosthesis ownership for residual limb pain (RLP) and nonpainful phantom limb sensations (npPLS).
The conclusions drawn were that prosthesis ownership was reduced in older participants and higher in lower-limb than in upper-limb amputees. A longer residual limb and more frequent prosthesis use and a longer time since amputation also yielded higher values.
Prostheses based on natural principles were associated with higher prosthesis ownership. PLP and RLP were lower with higher prosthesis ownership, and RLP but not PLP was lower when prosthesis use was frequent. No significant associations for npPLS were drawn.
The regression results differ in some aspects from those revealed by univariate analyses, emphasizing the importance of multivariate statistical approaches.
The researchers indicated that these findings provide insights into the interplay of body- and pain-related sensations after amputation and may help to provide a framework for new treatment approaches for both PLP and RLP. (See Bekrater-Bodmann R, Reinhard I, Diers M, et al. Relationship of prosthesis ownership and phantom limb pain: results of a survey in 2383 limb amputees. Pain. 2021;162(2):630-640. doi:10.1097/j.pain.0000000000002063.)
Case Report Shows Stellate Ganglion Block Effective in Management of Chronic Pericardial Chest Pain
Although the underlying pathophysiology and treatment of chronic pericardial chest pain remains unclear, a case report published in Anesthesia & Analgesia Practice described a young woman with chronic chest pain in the context of Marfan syndrome, whose status was post-valve-sparing aortic root repair, and who had recurrent pericarditis. The chronic pericardial pain was considered to be secondary to recurrent pericarditis, refractory to pharmacotherapy. A left-sided stellate ganglion block was performed for both diagnostic and therapeutic purposes. Postprocedure follow-up demonstrated significant analgesic benefit at 8 months after the procedure. (See Feigin G, Wang NN, Flamer D. Stellate ganglion block as a diagnostic and therapeutic option in chronic pericardial pain: a case report. A & A Practice. 2021;15(1):e01375. doi:10.1213/XAA.0000000000001375.)
Poor Glycemic Control Increases Risks of COVID-19 Complications and Death
Diabetic patients with insufficient glycemic control are more likely to experience poor outcomes, including death, if infected with coronavirus disease-2019 (COVID-19), according to a Chinese study.
In a recent Chinese study, diabetic patients with poor glycemic control experienced worse outcome if infected with COVID-19. Severe pulmonary infection and acute respiratory distress syndrome appeared to be the primary cause of death (J Diabetes Investig [published online ahead of print October 9, 2020]. doi:10.1111/jdi.13431).
The retrospective study included 77 laboratory-confirmed adult inpatients admitted to the intensive care unit at the Sino-French New City Branch of Tongji Hospital, in Wuhan, China. Patients were grouped into those with sufficient glycemic control, identified as an HbA1c less than 6.5% (Gp 1), and insufficient glycemic control (HbA1c of >=6.5%, Gp 2).
Patients in Gp2 had several risk factors upon admission, including a higher heart rate, lower percutaneous oxygen saturation, higher levels of multiple indicators of inflammation, and lower lymphocyte counts. Patients in Gp2 were also more likely to develop secondary respiratory infections (89% vs 67%) and acute respiratory distress syndrome (61% vs 29%). Significantly more of the insufficiently controlled patients became critically ill (68% vs 37%) and died (46% vs 22%).
A similar study in the United States demonstrated that mortality rates were 4 times higher among the population with less well-controlled glycemia (J Diabetes Sci Technol. 2020;14(4):813-821).
These findings underscore the need for vigilance in managing patients with diabetes and those receiving corticosteroids in any form, despite challenges in accessing the health care system during the COVID-19 pandemic. (Originally published in, Infectious Disease Special Edition, McMahon Publishing, and later in Anesthesiology News, February 4, 2021.)
Stratification of Patients With Neuropathic Pain Shown to Indicate Better Treatment Strategies
Personalized neuropathic pain treatment could be improved by the identification of specific sensory phenotypes (specific combinations of symptoms and signs) that are predictive of the response to different classes of drugs, according to a recent study.
The authors performed cluster analyses on 628 patients from their internal database with various etiologies of neuropathic pain. They identified 3 subgroups of patients based on specific combinations of symptoms (ie, pain descriptors) assessed with the Neuropathic Pain Symptom Inventory (NPSI):
* Group 1, "pinpointed pain," was mainly characterized by higher scores for paresthesia-related NPSI items (pins and needles and tingling) and below average scores for evoked pain (pain provoked by brush, pressure, or cold).
* Group 2, "evoked pain," was characterized by above average scores for evoked pain and electric shocks and below average deep pain and paresthesia scores.
* Group 3, "deep pain," was characterized principally by higher scores for the deep pain-related items (squeezing and pressure pain) and below average paresthesia scores.
An algorithm was developed for assigning each patient to 1 of these 3 clusters. Researchers evaluated the clinical relevance of this algorithm for predicting treatment response, through post hoc analyses of 2 previous controlled trials of the effects of subcutaneous injections of botulinum toxin A.
Each of the 97 patients with neuropathic pain included in these studies was individually allocated to 1 cluster, by applying the algorithm to their baseline NPSI responses. Significant effects of botulinum toxin A relative to placebo in clusters 2 and 3, but not in cluster 1, suggested that this approach was, indeed, relevant. A preliminary validation of a web-based version of the NPSI was then determined.
The researchers concluded that the personalization of neuropathic pain treatment could be improved by identifying specific sensory phenotypes (ie, specific combinations of symptoms and signs) predictive of the response to different classes of drugs. They performed a preliminary validation of a web-based version of the NPSI and algorithm for the stratification of patients in both research and daily practice. (See Bouhassira D, Branders S, Attal N, et al. Stratification of patients based on the Neuropathic Pain Symptom Inventory: development and validation of a new algorithm. Pain. 2021;162(4):1038-1046. doi:10.1097/j.pain.0000000000002130.)