Understanding the Psychophysiological Mechanisms Related to Widespread Pressure Pain Hyperalgesia Underpinning Carpal Tunnel Syndrome: A Network Analysis Approach

Surgery for carpal tunnel syndrome in patients with and without diabetes-Is there a difference in the frequency of surgical procedures?

Carpal tunnel syndrome (CTS) occurs more often among individuals with diabetes. The aim of this retrospective observational registry study was to examine whether individuals with diabetes and CTS are treated surgically to the same extent as individuals with CTS but without diabetes. Data on CTS diagnosis and surgery were collected from the Skåne Healthcare Register (SHR). A total of 35,105 individuals (age ≥ 18 years) diagnosed with CTS from 2004-2019 were included. Data were matched to the Swedish National Diabetes Register (NDR. Cox regression models were used to calculate the risk of the use of surgical treatment. Of the 35,105 included individuals with a CTS diagnosis, 17,662 (50%) were treated surgically, and 4,966 (14%) had diabetes. A higher number of individuals with diabetes were treated surgically (2,935/4,966, 59%) than individuals without diabetes (14,727/30,139, 49%). In the Cox regression model, diabetes remained a significant risk factor for surgical treatment (PR 1.14 (95% CI 1.11-1.17)). Individuals with type 1 diabetes were more frequently treated surgically (490/757, 65%) than individuals with type 2 diabetes (2,445/4,209, 58%). There was no difference between the sexes and their treatment. The duration of diabetes was also a risk factor for surgical treatment in diabetes type 2, but high HbA1c levels were not. Individuals with diabetes are more likely to be treated surgically for CTS than individuals without diabetes. Individuals with type 1 diabetes are more likely to be treated surgically for CTS than individuals with type 2 diabetes.

Central Sensitization in Patients with Chronic Pain Secondary to Carpal Tunnel Syndrome and Determinants

Purpose

Central sensitization (CS) is commonly seen in chronic pain disorders, including neuropathic pain. However, there exist inconsistencies concerning the presence of CS in chronic pain secondary to carpal tunnel syndrome (CTS). CS and neuropathic pain manifestations in CTS remain not well established. Therefore, this study aims to investigate the CS and pain profiles in patients with CTS and to explore the potential determinants associated with CS.

Patients and Methods

Patients with suspected CTS symptoms lasting 3 months or above and healthy controls were enrolled. History, physical examinations, and nerve conduction studies were employed to confirm the diagnosis and severity of median nerve dysfunction. The central sensitization inventory (CSI) was used to screen CS. Other outcomes included neuropathic pain, CTS-specific symptom severity and functions, emotion, and health-related quality of life. Between-group comparisons were conducted in terms of the CS presence. Logistic regression analysis was performed to identify determinants associated with CS.

Results

Over 60% of participants with CTS were found with clinical CS, significantly higher than that in the control group. More than 70% of the CTS participants were identified to have possible or very likely neuropathic pain components. In addition, one-fourth of CTS cases had depression or anxiety. Anxiety was associated with an increased risk of developing CS in CTS (adjusted OR=1.31, 95% CI 1.08-1.59), whereas higher self-perceived general health rating was negatively associated with the presence of CS (adjusted OR=0.92, 95% CI 0.88-0.97) in the multivariate adjusted regression model.

Conclusion

CS is prevalent in patients with CTS. Predominant neuropathic pain characteristics were uncovered in CTS patients as well as comorbid psychological distress. Significant association was found between anxiety and CS presence. Self-perceived general health was inversely related to CS. Further research is warranted to explore the mechanisms of anxiety and central pain processing in painful entrapment neuropathy.

Effects of mirror therapy on pain, sensitivity and functionality in patients with unilateral carpal tunnel syndrome. Randomised control trial

PURPOSE

To investigate the effects of mirror therapy (MT) and therapeutic exercise (TE) with the unaffected hand, on pain, sensitivity and functionality in individuals with unilateral carpal tunnel syndrome (CTS).

MATERIAL AND METHODS

A randomized controlled trial was carried out. Thirty-nine adults with unilateral CTS were included and randomly allocated to a six-week training programme based on MT (n = 20) or TE (n = 19). Visual Analogue Scale, Semmes-Weinstein monofilament test, Two-point discrimination (2PD), Disabilities of the Arm, Shoulder and Hand (DASH) and Boston Carpal Tunnel Questionnaire (BCTQ) were assessed before (T0) and after the intervention (T1), and at one-month follow-up (T2).

RESULTS

At T1, MT and TE showed significant improvements in pain (p = 0.001 and p = 0.03, respectively), however, only MT maintained the achieved effects at T2 (p = 0.01). In addition, 2PD significantly improved in MT in the first (p = 0.04) and fourth fingers (p = 0.02) at T1. The DASH score decreased at T1 in MT (p < 0.001) and TE (p = 0.01). Additionally, the BCTQ score improved in MT (p < 0.001), and TE (p < 0.001) at T1. The effects were maintained at T2 for DASH and BCTQ scores.

CONCLUSIONS

Training of the unaffected hand resulted in a significant improvement of the affected hand in both groups; nevertheless, MT achieved a longer duration of the effects.

Network Analysis Reveals That Headache-Related, Psychological and Psycho-Physical Outcomes Represent Different Aspects in Women with Migraine

Evidence supports that migraine is a complex pain condition with different underlying mechanisms. We aimed to quantify potential associations between demographic, migraine-related, and psychophysical and psychophysical variables in women with migraine. Demographic (age, height, and weight), migraine-related (intensity, frequency, and duration), related-disability (Migraine Disability Assessment Scale, Headache Disability Inventory), psychological (Hospital Anxiety and Depression Scale), and psycho-physical (pressure pain thresholds -PPTs-) variables were collected from a sample of 74 women suffering from migraine. We calculated adjusted correlations between the variables by using a network analysis. Additionally, we also calculated centrality indices to identify the connectivity among the variables within the network and the relevance of each variable in the network. Multiple positive correlations (ρ) between PPTs were observed ranging from 0.1654 (C5-C6 and tibialis anterior) to 0.40 (hand and temporalis muscle). The strongest associations within the network were those between migraine attack frequency and diagnosis of chronic migraine (ρ = 0.634) and between the HDI-E and HDI-P (ρ = 0.545). The node with the highest strength and betweenness centrality was PPT at the second metacarpal, whereas the node with the highest harmonic centrality was PPT at the tibialis anterior muscle. This is the first study applying a network analysis to understand the underlying mechanisms in migraine. The identified network revealed that a model where each subgroup of migraine-related, psychological, and psycho-physical variables showed no interaction between each variable. Current findings could have clinical implications for developing multimodal treatments targeting the identified mechanisms.

Understanding Sensitization, Cognitive and Neuropathic Associated Mechanisms behind Post-COVID Pain: A Network Analysis

This study aimed to describe a network including demographic, sensory-related, psychological/cognitive and other variables in individuals with post-COVID pain after hospitalization. Demographic (i.e., age, height, weight, months with symptoms), sensory-related (Central Sensitization Inventory -CSI-, Self-Report Leeds Assessment of Neuropathic Symptoms -S-LANSS-, PainDETECT), psychological/cognitive (Hospital Anxiety and Depression Scale -HADS-A/HADS-D-, Pain Catastrophizing Scale -PCS-, Tampa Scale for Kinesiophobia -TSK-11-) and other (sleep quality and health-related quality of life -EQ/5D/5L) variables were collected in 146 COVID-19 survivors with post-COVID pain. A network analysis was conducted to quantify the adjusted correlations between the modelled variables, and to assess their centrality indices (i.e., the connectivity with other symptoms in the network and the importance in the system modelled as network). The network revealed associations between sensory-related and psychological/cognitive variables. PainDETECT was associated with S-LANSS (ρ: 0.388) and CSI (ρ: 0.207). Further, CSI was associated with HADS-A (ρ: 0.269), TSK-11 (ρ: 0.165) and female gender (ρ: 0.413). As expected, HADS-A was associated with HADS-D (ρ: 0.598) and TSK-11 with PCS (ρ: 0.405). The only negative association was between sleep quality and EQ-5D-5L (ρ: −0.162). Gender was the node showing the highest strength, closeness, and betweenness centralities. In addition, CSI was the node with the second highest closeness and betweenness centralities, whereas HADS-D was the node with the second highest strength centrality. This is the first study applying a network analysis for phenotyping post-COVID pain. Our findings support a model where sensitization-associated symptoms, neuropathic phenotype, and psychological aspects are connected, reflecting post-COVID pain as a nociplastic pain condition. In addition, post-COVID pain is gender dependent since female sex plays a relevant role. Clinical implications of current findings, e.g., developing treatments targeting these mechanisms, are discussed.