Molecular and pathological studies in the posterior interosseous nerve of diabetic and non-diabetic patients with carpal tunnel syndrome

Carpal Tunnel Syndrome and Trigger Finger May Be an Early Symptom of Preclinic Type 2 Diabetes

Background

Type 2 diabetes (T2D) is a major risk factor for carpal tunnel syndrome (CTS) and trigger finger (TF), but less is known regarding the risk of developing T2D after being diagnosed with CTS or TF. CTS and TF could be early signs of preclinical T2D, and early detection of T2D is crucial to prevent complications and morbidity. Therefore, we investigate the association between CTS/TF and T2D in an adult population without previous T2D using big data registers in Sweden.

Methods

Data were collected by crosslinking five nationwide Swedish registers. Individuals aged 40-85 years on December 31, 2010, without prior overt diabetes, were included (n = 3,948,517) and followed up from baseline (ie, a diagnosis of CTS or TF) or January 1, 2011, for controls, until a diagnosis of T2D, prescription of oral antidiabetics or insulin, or end of follow-up four years after baseline. Multivariate Cox regression models were created to calculate hazard ratios for T2D.

Results

In total, 37,346 (0.95%) patients were diagnosed with CTS, whereof 1329 (3.46%) developed T2D. There were 17,432 (0.44%) patients who developed TF, whereof 639 (3.67%) developed T2D. Among the controls, 2.73% developed T2D. Compared with controls, there was an increased risk of developing T2D after being diagnosed with either CTS (HR 1.35; 95% confidence interval 1.28-1.43) or TF (HR 1.21; 95% confidence interval 1.12-1.31).

Conclusion

Compared with controls, a diagnosis of CTS or TF was associated with 35% and 21% higher risk for later T2D, respectively, which might indicate the existence of undetected T2D in this population.

Carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is the most common nerve entrapment disorder worldwide. The epidemiology and risk factors, including family burden, for developing CTS are multi-factorial. Despite much research, its intricate pathophysiological mechanism(s) are not fully understood. An underlying subclinical neuropathy may indicate an increased susceptibility to developing CTS. Although surgery is often performed for CTS, clear international guidelines to indicate when to perform non-surgical or surgical treatment, based on stage and severity of CTS, remain to be elucidated. Neurophysiological examination, using electrophysiology or ultrasonography, performed in certain circumstances, should correlate with the history and findings in clinical examination of the person with CTS. History and clinical examination are particularly relevant globally owing to lack of other equipment. Various instruments are used to assess CTS and treatment outcomes as well as the effect of the disorder on quality of life. The surgical treatment options of CTS - open or endoscopic - offer an effective solution to mitigate functional impairments and pain. However, there are risks of post-operative persistent or recurrent symptoms, requiring meticulous diagnostic re-evaluation before any additional surgery. Health-care professionals should have increased awareness about CTS and all its implications. Future considerations of CTS include use of linked national registries to understand risk factors, explore possible screening methods, and evaluate diagnosis and treatment with a broader perspective beyond surgery, including psychological well-being.

Khachatryan L, Mohammadian-Hafshejani A. Investigating the association between diabetes and carpal tunnel syndrome: A systematic review and meta-analysis approach

INTRODUCTION

In recent years, several studies have reported on the relationship between diabetes and carpal tunnel syndrome (CTS). However, due to their contradictory results, a systematic review and meta-analysis were conducted to investigate this subject.

METHODS

This study is a systematic review and meta-analysis of studies published in ISI Web of Science, Scopus, PubMed, Cochrane, Google Scholar, and Embase databases. Heterogeneity in the studies included in the meta-analysis was evaluated using statistical tests such as the Chi-square test, I2, and forest plots. Publication bias was assessed using Begg's and Egger's tests.

RESULTS

This investigation analyzed data from 42 studies conducted between 1985 and 2022, with a total of 3,377,816 participants. The meta-analysis demonstrated that the odds ratio (OR) of CTS in participants with a history of diabetes compared to those without was 1.90 (95% CI: 1.64-2.21; P-value < 0.001). Given that publication bias was observed in this study (Begg's test P-value = 0.01), the modified OR was calculated with consideration of missed studies, which was 1.68 (95% CI: 1.45-1.94; P-value < 0.001).

CONCLUSION

The results of this study suggest that diabetic patients have 90% higher odds of developing CTS compared to non-diabetic individuals, which is statistically significant.

The Unpredictable Ulnar Nerve-Ulnar Nerve Entrapment from Anatomical, Pathophysiological, and Biopsychosocial Aspects

Peripheral nerves consist of delicate structures, including a rich microvascular system, that protect and nourish axons and associated Schwann cells. Nerves are sensitive to internal and external trauma, such as compression and stretching. Ulnar nerve entrapment, the second most prevalent nerve entrapment disorder after carpal tunnel syndrome, appears frequently at the elbow. Although often idiopathic, known risk factors, including obesity, smoking, diabetes, and vibration exposure, occur. It exists in all adult ages (mean age 40-50 years), but seldom affects individuals in their adolescence or younger. The patient population is heterogeneous with great co-morbidity, including other nerve entrapment disorders. Typical early symptoms are paresthesia and numbness in the ulnar fingers, followed by decreased sensory function and muscle weakness. Pre- and postoperative neuropathic pain is relatively common, independent of other symptom severity, with a risk for serious consequences. A multimodal treatment strategy is necessary. Mild to moderate symptoms are usually treated conservatively, while surgery is an option when conservative treatment fails or in severe cases. The decision to perform surgery might be difficult, and the outcome is unpredictable with the risk of complications. There is no consensus on the choice of surgical method, but simple decompression is relatively effective with a lower complication rate than transposition.

Occupational and non-occupational risk factors correlating with the severity of clinical manifestations of carpal tunnel syndrome and related work disability among workers who work with a computer

The contribution of certain occupational and personal factors to the development of carpal tunnel syndrome (CTS) is still uncertain. We investigated which specific occupational and non-occupational factors correlate with the level of clinical manifestations and work disability related to CTS. The study included 190 workers who work with a computer and have diagnosed CTS (100 men, 90 women, aged 20-65 years). Subjective experience of CTS-related impairments was assessed with the Symptom Severity Scale (SSS) and the Functional Status Scale (FSS) of the Boston Carpal Tunnel Syndrome Questionnaire (BCTQ). The objective, neural impairments were tested with electrodiagnostics (EDX), whereas CTS-related work disability data were collected from medical records. We found a high inter-correlation between BCTQ, EDX, and work disability data. These also showed high correlations with certain occupational factors (duration of computer-working in months and hours spent daily in computer-working, certain ergonomic, microclimatic, and other occupational conditions) and non-occupational factors (demographic and lifestyle factors: nutritional status, diet, smoking, alcohol consumption, and physical activity). Despite its limitations, our study has identified occupational and non-occupational risk factors that can aggravate CTS and work disability, but which can also be improved with workplace and lifestyle preventive and corrective measures. More research is needed, though, to establish the possible causal relationships and the independent influence of each of those risk factors.

Exposure to hand-held vibrating tools and biomarkers of nerve injury in plasma: a population-based, observational study

OBJECTIVES

To analyse potential biomarkers for vibration-induced nerve damage in a population-based, observational study.

DESIGN

Prospective cohort study.

SETTING

Malmö Diet Cancer Study (MDCS), Malmö, Sweden.

PARTICIPANTS

In a subcohort of 3898 individuals (recruited 1991-1996) from MDCS (baseline examination in 28 449 individuals; collection of fasting blood samples in a cardiovascular subcohort of MDCS of 5540 subjects), neuropathy-relevant plasma biomarkers were analysed during follow-up after filling out questionnaires, including a question whether work involved hand-held vibrating tools, graded as 'not at all', 'some' or 'much'.

PRIMARY OUTCOME MEASURES

The neuropathy-relevant plasma biomarkers vascular endothelial growth factor (VEGF)-A, VEGF-D, VEGF receptor 2, galanin, galectin-3, HSP27, ß-nerve growth factor, caspase-3, caspase-8, transforming growth factor-α and tumour necrosis factor were analysed. Data were analysed by conventional statistics (Kruskal-Wallis test; post hoc test Mann-Whitney U test; Bonferroni correction for multiple testing) and in a subanalysis for galanin using two linear regression models (unadjusted and adjusted).

RESULTS

Among participants, 3361 of 3898 (86%) reported no work with hand-held vibrating tools, 351 of 3898 (9%) reported some and 186 of 3898 (5%) much work. There were more men and smokers in vibration-exposed groups. Galanin levels were higher after much vibration exposure (arbitrary units 5.16±0.71) compared with no vibration exposure (5.01±0.76; p=0.015) with no other observed differences.

CONCLUSIONS

Higher plasma levels of galanin, possibly related to magnitude, frequency, acceleration and duration, as well as to severity of symptoms of vibration exposure, may be found in individuals working with hand-held vibrating tools.

Nerve ultrasonographic findings in diabetes mellitus are determined by anatomical location and type of diabetes

Objective

A prospective ultrasound study to analyze nerve size and its modifying factors in type 1 and type 2 diabetes mellitus.

Methods

The cross-sectional areas (CSAs) of motor and sensory nerves in both upper and lower limbs were measured at 14 measurement points, using high resolution ultrasound in 26 patients with type 1 and 76 patients with type 2 diabetes, and in 50 control subjects. All diabetic patients underwent electrophysiological assessment to check for the presence of polyneuropathy.

Results

Significant mild/moderate diffuse nerve enlargement was demonstrated in type 2 diabetes, more pronounced at compression sites versus non-compression sites, and on the upper limbs versus lower limbs (p value for pooled DM2 v. control group: <0.001). In type 1 diabetes, nerve enlargement was found only at one compression site (median nerve wrist; p = 0.002). No significant difference was found between patients with or without polyneuropathy.

Conclusions

The primary predictors of nerve size in diabetes are anatomical location (i.e. compression sites versus non-compression sites, upper versus lower limbs) and type of diabetes. Changes occur before the electrophysiological signs of polyneuropathy are detected.

Significance

Nerve ultrasound may contribute to early recognition of the neuropathic complications of diabetes.

The Interaction of Diabetic Peripheral Neuropathy and Carpal Tunnel Syndrome

BACKGROUND

Diabetes mellitus (DM) increases the risk for carpal tunnel syndrome (CTS) and is associated with its own neuropathic complications. Diabetic peripheral neuropathy (DPN) is a common complication seen in diabetic patients. In this study, we examine the relationship between the severity of DPN and CTS.

METHODS

Type 2 diabetic and control patients (n = 292) were recruited at a clinic visit. The Michigan Neuropathy Screening Instrument (MNSI) questionnaire was used to collect data related to peripheral neuropathy. The MNSI scores were compared for patients with CTS with and without DM in univariable and multivariable analyses. χ2 analyses were performed to quantitatively measure the associations between peripheral neuropathy and the presence of CTS.

RESULTS

Of the 292 patients, 41 had CTS, and 19 of these had both CTS and DM. Of the 138 diabetic patients, 85 had peripheral neuropathy. There was no association between a diagnosis of CTS and an MNSI score indicative of peripheral neuropathy. In the diabetic population, CTS was inversely associated with DPN (P = .017). The MNSI scores between diabetic and control patients with CTS were comparable.

CONCLUSION

The severity of peripheral neuropathy in diabetic patients with and without CTS is comparable. Diabetic patients without peripheral neuropathy have an association with higher incidence of CTS in this study, suggesting that there are disparate mechanisms causing DPN and CTS. Nevertheless, diabetes and CTS are risk factors for developing the other, and future studies should further explore how DPN and CTS differ to tailor patient interventions based on their comorbidities.

Ultrasonography for the diagnosis of carpal tunnel syndrome: an umbrella review

BACKGROUND

Numerous sonographic modalities and parameters have been used to diagnose carpal tunnel syndrome (CTS), with varying accuracy. Our umbrella review aimed to summarize the evidence from systematic reviews and meta-analyses regarding the use of ultrasound imaging to diagnose CTS.

METHODS

Systematic reviews and meta-analyses meeting the inclusion criteria were searched in PubMed, Embase, Medline, Web of Science, and Cochrane databases from inception to March 2022. Critical appraisal, data extraction, and synthesis were performed in accordance with the criteria for conducting an umbrella review.

RESULTS

Sixteen reviews were included. Three reviews were classified as high quality, one as moderate, four as low, and eight as critically low. The cross-sectional area (CSA) of the median nerve at the carpal tunnel inlet demonstrated the best reliability and diagnostic accuracy among multiple parameters. A cutoff CSA value of 9-10.5 mm² gave the highest diagnostic performance in the general population. The degree of CSA enlargement was correlated with CTS severity. Sonoelastography and Doppler ultrasound might provide additional insights into CTS evaluation as median nerve stiffness and vascularity at the wrist were increased in these patients.

CONCLUSIONS

Sonography is a reliable tool to diagnose CTS, with inlet CSA being the most robust parameter. Sonoelastography and Doppler ultrasound can serve as auxiliary tools to confirm CTS diagnoses. Further studies are needed to expand the use of sonography for diagnosing CTS, especially in the presence of concomitant neuromuscular disease(s).

Electromyographic and Clinical Investigation of the Effect of Platelet-Rich Plasma on Peripheral Nerve Regeneration in Patients with Diabetes after Surgery for Carpal Tunnel Syndrome

Background Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy. Studies have shown that results of CTS surgery are poorer in patients with diabetes. In this study, the effect of platelet-rich plasma (PRP) on nerve regeneration was investigated through clinical and electromyographic findings in patients with diabetes who underwent CTS surgery.

Methods A retrospective analysis of 20 patients with diabetes who had surgically decompressed CTS was conducted. Patients were divided into two groups. The study group received PRP treatment following surgery. The control group did not receive any treatment. Patients were assessed using electromyography and the Boston Carpal Tunnel Syndrome Questionnaire preoperatively as well as postoperatively at 3-month, 6-month, and 1-year follow-ups visits.

Results There was a decrease in complaints and an improvement in sensory and motor examinations in both groups. The Boston Carpal Tunnel Syndrome Questionnaire scores did not show any statistically significant differences between the two groups. However, electromyographic findings showed that there were statistical differences between preoperative and postoperative (3 months, 6 months, and 1 year) results in both groups. When the two groups were compared using preoperative and postoperative (3 months, 6 months, and 1 year) electromyographic values, no statistically significant differences were seen.

Conclusion Single injections of PRP did not have a significant impact on median nerve regeneration following CTS surgery in patients with diabetes. The effectiveness of multiple PRP injections can be investigated in patients with diabetes in future studies.

Carpal Tunnel Syndrome and Diabetes—A Comprehensive Review

Carpal tunnel syndrome (CTS) is the most common compression neuropathy in the general population and is frequently encountered among individuals with type 1 and 2 diabetes. The reason(s) why a peripheral nerve trunk in individuals with diabetes is more susceptible to nerve compression is still not completely clarified, but both biochemical and structural changes in the peripheral nerve are probably implicated. In particular, individuals with neuropathy, irrespective of aetiology, have a higher risk of peripheral nerve compression disorders, as reflected among individuals with diabetic neuropathy. Diagnosis of CTS in individuals with diabetes should be carefully evaluated; detailed case history, thorough clinical examination, and electrophysiological examination is recommended. Individuals with diabetes and CTS benefit from surgery to the same extent as otherwise healthy individuals with CTS. In the present review, we describe pathophysiological aspects of the nerve compression disorder CTS in relation to diabetes, current data contributing to the explanation of the increased risk for CTS in individuals with diabetes, as well as diagnostic methods, treatment options, and prognosis of CTS in diabetes.

Carpal Tunnel Syndrome in Diabetes Mellitus

The aim of the present brief review was to discuss carpal tunnel syndrome (CTS) in diabetes mellitus (DM). Generally, CTS is more common in DM, especially in subjects with coexisting diabetic polyneuropathy (DPN) and/or long DM duration. There is no agreement if it is more frequent in type 1 or type 2 DM. The precise underlying mechanisms are not entirely clear but appear to involve hyperglycaemia-induced median nerve oedema, increased sensitivity to exogenous trauma and nerve myelin ischaemia and axonal degeneration. More recently, increased vascular endothelial growth factor (VEGF) and advanced glycation endproducts (AGEs) appear to also play an important role. Median nerve conduction study remains the cornerstone of CTS diagnosis in DM, being more sensitive than clinical examination. CTS can be treated medically or surgically. The latter appears now to be equally effective in subjects with vs. without DM in terms of recurrence rates and quality of life.

Diabetic polyneuropathy and carpal tunnel syndrome together affect hand strength, tactile sensation and dexterity in diabetes patients

AIMS/INTRODUCTION

Carpal tunnel syndrome (CTS) and diabetic polyneuropathy (DPN) can occur together, and this concomitance is thought to be higher in diabetes patients. We aimed to examine and compare hand function in type 2 diabetes mellitus patients without CTS and DPN (CTS-DPN-), patients with CTS without DPN (CTS+DPN-), patients with DPN without CTS (CTS-DPN+), and patients with CTS and DPN (CTS+DPN+).

MATERIALS AND METHODS

A total of 161 type 2 diabetes mellitus patients underwent physical examination and electrodiagnostic tests. Grip and pinch strengths, tactile sensory thresholds were measured for each participant. Purdue pegboard test was used in evaluating the hand dexterity of the participants.

RESULTS

Of the 161 type 2 diabetes mellitus participants, 36 (22.4%) had both CTS and DPN. CTS participants had lower grip (26.6 ± 10.6 vs 35.2 ± 14.3, P < 0.001) and pinch (6.3 ± 2.6 vs 7.5 ± 2.9, P = 0.026) strengths compared with non-CTS participants, whereas DPN participants had elevated tactile sensory thresholds of both the second (2.8 [2.8-3.6] vs 2.4 [2.4-2.8], P < 0.001) and the fifth (2.8 [2.8-3.6] vs 2.4 [2.4-2.8], P < 0.001) fingers compared with non-DPN participants. The CTS+DPN+ group had lower Purdue pegboard test scores than other groups. Grip (r = 0.482, 0.530, 0.467, 0.498, all P < 0.001) and pinch (r = 0.246, P = 0.003; r = 0.265, P = 0.001; r = 0.264, P = 0.001; r = 0.235, P = 0.005) strengths were positively correlated with Purdue pegboard test scores, whereas tactile sensory thresholds were negatively correlated with Purdue pegboard test scores (r = -0.447 to -0.359, all P < 0.001).

CONCLUSION

Type 2 diabetes mellitus patients with both DPN and CTS had lower grip and pinch strengths and decreased tactile sensation, both of which were correlated with poorer hand dexterity.

Vibrotactile sense 5 years after carpal tunnel release in people with diabetes: A prospective study with matched controls

AIM

To compare vibrotactile sense, 5 years after carpal tunnel release in people with and without diabetes.

METHODS

Out of 35 people with diabetes and carpal tunnel syndrome, age- and gender-matched with 31 people without diabetes but with idiopathic carpal tunnel syndrome, 27 and 30 people, respectively, participated in this prolonged follow-up. Vibration perception threshold of the index and little finger (median and ulnar nerve, respectively), 5 years after surgery, was measured at seven different frequencies (8, 16, 32, 64, 125, 250 and 500 Hz).

RESULTS

Significant improvement of vibration perception threshold from 1 to 5 years after carpal tunnel release was found at 64 Hz for people with diabetes, while improvement for people without diabetes was demonstrated at several frequencies (64-250 Hz). However, both groups demonstrated a significant decrease in vibration perception threshold for the low frequencies (8-16 Hz). At 5 years, people with diabetes had significantly impaired vibration perception threshold at the index finger for high frequencies (125-500 Hz), and for nearly all frequencies (16 Hz, 64-500 Hz) at the little finger, compared to people without diabetes.

CONCLUSION

After carpal tunnel release, significant mid-term improvement of vibrotactile sense appears limited for people with diabetes, compared to a continuous improvement for people without diabetes. In addition, a decline in low-frequency vibrotactile sense occurs for the median as well as the ulnar nerve innervated fingers. Clinical Trial Registration NCT01201109.

Electrodiagnostic Testing Characteristics of Diabetic People with Carpal Tunnel Syndrome

Objective  The present study aimed to correlate electroneuromyography (ENMG) findings in diabetic and nondiabetic subjects with carpal tunnel syndrome (CTS).

Methods  In total, 154 patients were evaluated in a hand surgery outpatient clinic. All ENMG tests were bilaterally performed by a single neurologist. Qualitative variables were described for all patients with CTS according to their diabetic status, and the chi-squared test was used to reveal any association. A joint model was adjusted to determine the influence of diabetes on ENMG severity in CTS patients.

Results  The sample consisted of 117 women and 37 men, with an average age of 56.9 years old. Electroneuromyography demonstrated bilateral CTS in 82.5% of the patients. Diabetes was identified in 21.4% of the cases. Severe ENMG was prevalent.

Conclusion  There was no association between diabetes and ENMG severity in patients with CTS. Level of evidence IV, case series.

Association of the role of personal variables and nonoccupational risk factors for work-related carpal tunnel syndrome

OBJECTIVES

The purpose of this study was to identify personal variables and nonoccupational risk factors for carpal tunnel syndrome and to analyse the strength of association of these factors.

METHODS

We performed a case-control study with 162 cases and 300 controls. We studied consecutive patients with an electrophysiologically confirmed diagnosis of symptomatic carpal tunnel syndrome. Univariate analysis was performed in the case group and control comparing them for presence of various risk factors. Multivariate analysis was carried out through logistic regression.

RESULTS

The mean BMI and age were greater in the case group than in the control. Multivariate analysis showed that BMI (OR = 1.05, 95% CI = 1.01-1.11) and arterial hypertension (OR = 4.63, 95% CI = 2.88-7.44) were the only factors significantly associated with carpal tunnel syndrome. The age, cigarette smoking and alcohol drinking were at the edge of significance.

CONCLUSIONS

Carpal tunnel syndrome is the most common peripheral neuropathy and has been related to occupational activities in some but not all studies. Clarifying this relationship has important implications for workers' compensation systems. Based on our findings, BMI and arterial hypertension are considered to be the most significant risk factors of carpal tunnel syndrome in our study.

Structural Changes in the Posterior Interosseous Nerve from Patients with Wrist Osteoarthritis and Asymptomatic Controls

Background  Posttraumatic morphological changes have been described in the posterior interosseous nerve (PIN) after mild wrist trauma, and it has been suggested that posttraumatic nerve changes may contribute to wrist pain. PIN excision has shown to relieve pain in some patients with wrist osteoarthritis. However, is not known if PINs from osteoarthritic wrist have pathological features. Objective  The aim of this study was to investigate whether PINs from osteoarthritic wrists show morphological changes that are not present in healthy wrists. Materials and Methods  PINs resected from 15 osteoarthritic wrists were analyzed with light microscopy regarding morphological changes and compared with five asymptomatic controls without osteoarthritis. Results  No significant differences in fascicular area, myelinated fiber density or myelinated fiber diameter were found. However, most patients and controls exhibited some degree of pathology, and a few samples from both groups exhibited severe pathological changes. Conclusions  Our findings of morphological changes in both patients with osteoarthritis and asymptomatic controls suggest that pathological changes of unknown significance might exist in the general population in the PIN at wrist level. We believe that the observed structural nerve changes in the PIN are unlikely to contribute to the symptoms of pain. Further studies of the normal histological appearance of the terminal PIN are needed. Level of Evidence  This is Level II study.

Diabetes mellitus as a risk factor for compression neuropathy: a longitudinal cohort study from southern Sweden

INTRODUCTION

Compression neuropathies (CN) in the upper extremity, the most common being carpal tunnel syndrome (CTS) and ulnar nerve entrapment (UNE), are frequent among patients with diabetes mellitus (DM). Earlier studies have shown contradicting results regarding DM as a risk factor for CN. Thus, the aim of the present population-based, longitudinal study was to explore potential associations between DM, CTS, and UNE during long-term follow-up.

RESEARCH DESIGN AND METHODS

A total of 30 466 participants aged 46-73 years, included in the population-based Malmö Diet and Cancer Study during 1991-1996, were followed up in Swedish national registries regarding incident CTS and UNE until 2016. Associations between prevalent DM at baseline and incident CTS or UNE were calculated using Cox proportional hazard models, adjusted for baseline confounders, such as sex, age at study entry, smoking, hypertension, use of antihypertensive treatment, alcohol consumption, and body mass index (BMI). HbA1c and fasting plasma glucose levels had been measured at baseline in a subgroup of 5508 participants and were related to incident CTS and UNE in age and sex-adjusted binary logistic regression models.

RESULTS

A total of 1081 participants developed CTS and 223 participants developed UNE during a median follow-up of 21 years. Participants with incident CTS or UNE had higher prevalence of DM and higher BMI at baseline. Using multivariate Cox regression models, prevalent DM at baseline was independently associated with both incident CTS (HR 2.10; 95% CI 1.65 to 2.70, p<0.0001) and incident UNE (HR 2.20; 95% CI 1.30 to 3.74, p=0.003). Higher levels of HbA1c and plasma glucose were associated with an increased risk for CTS, but not for UNE.

CONCLUSION

This study establishes DM as a major risk factor in the development of both CTS and UNE. Furthermore, a higher BMI is associated with both CTS and UNE. Finally, hyperglycemia seems to affect the median and ulnar nerves differently.

Distribution of Highly Prevalent Musculoskeletal Disorders and Their Association With Diabetes Complications in a Population of 140 Individuals With Type 1 Diabetes: A Retrospective Study in a French Diabetes Center

Although they are usually not considered to be diabetes complications, musculoskeletal disorders (MSKDs) are common in individuals with type 1 or type 2 diabetes and can strongly interfere with daily diabetes care, especially in people using diabetes technologies. The authors of this retrospective study in a population of 140 patients with type 1 diabetes report the distribution of subtypes of MSKDs and speculate about the mechanisms involved. The authors emphasize the need for multidisciplinary care involving not only the diabetes care team but also orthopedic surgeons. This report should lead to large, prospective studies to increase knowledge about these under-studied complications.

Open carpal tunnel release and diabetes: a retrospective study using PROMs and national quality registries

OBJECTIVES

To study patient-reported outcome after open carpal tunnel release (OCTR) for carpal tunnel syndrome (CTS) in patients with or without diabetes using national healthcare quality registries.

DESIGN

Retrospective cohort study.

SETTING

Data from the Swedish National Quality Registry for Hand Surgery (HAKIR; www.hakir.se) were linked to data from the Swedish National Diabetes Register (NDR; www.ndr.nu).

PARTICIPANTS

We identified 9049 patients (10 770 hands) operated for CTS during the inclusion period (2010-2016).

PRIMARY OUTCOME MEASURES

Patient-reported outcome measures were analysed before surgery and at 3 and 12 months postoperatively using the QuickDASH as well as the HAKIR questionnaire with eight questions on hand symptoms and disability.

RESULTS

Patients with diabetes (n=1508; 14%) scored higher in the QuickDASH both preoperatively and postoperatively than patients without diabetes, but the total score change between preoperative and postoperative QuickDASH was equal between patients with and without diabetes. The results did not differ between patients with type 1 or type 2 diabetes. Patients with diabetic retinopathy scored higher in QuickDASH at 3 months postoperatively than patients with diabetes without retinopathy. In the regression analysis, diabetes was associated with more residual symptoms at 3 and 12 months postoperatively.

CONCLUSIONS

Patients with diabetes experience more symptoms both before and after OCTR, but can expect the same relative improvement from surgery as patients without diabetes . Patients with retinopathy, as a proxy for neuropathy, may need longer time for symptoms to resolve after OCTR. Smoking, older age, higher HbA1c levels and receiving a diabetes diagnosis after surgery were associated with more residual symptoms following OCTR.

Can ultrasound imaging be used for the diagnosis of carpal tunnel syndrome in diabetic patients? A systemic review and network meta-analysis

BACKGROUND

High-resolution ultrasound (US) becomes a reliable tool for diagnosing carpal tunnel syndrome (CTS), but whether it can be applied to patients with preexisting diabetes mellitus (DM) remains unclear.

METHODS

We searched PubMed and Embase and systemically reviewed studies exploring the median nerve CSAs at the wrist level by US imaging. Nine studies enrolling at least one subgroup comprising patients with both DM and CTS were included for network meta-analysis. The primary outcome was the inter-group difference of the wrist-level median nerve CSA.

RESULTS

The median nerve size at the wrist level was larger in patients with only CTS than in patients with only DM [CSA difference = 3.14 mm², 95% confidence interval (CI) 1.92-4.35]. Patients with DM and CTS had a slightly enlarged median nerve CSA than did patients with only CTS, but the difference was not statistically significant (0.52 mm², 95% CI - 0.54 to 1.59). According to rank probabilities, median nerve CSAs in patients with DM and CTS were likely to be ranked as the largest, followed by patients with only CTS, patients with only DM, and healthy controls. Furthermore, median nerve CSAs seemed smaller in patients with than without diabetic polyneuropathy.

CONCLUSIONS

Although DM causes swelling of the median nerve at the wrist level, patients with CTS have a larger CSA regardless of preexisting DM. The add-on effect of DM on median nerve CSAs in patients with CTS is limited. Diabetic polyneuropathy tends to result in less swollen median nerves in the CTS population.

Diagnosing and managing diabetic somatic and autonomic neuropathy

The diagnosis and management of diabetic neuropathy can be a major challenge. Late diagnosis contributes to significant morbidity in the form of painful diabetic neuropathy, foot ulceration, amputation, and increased mortality. Both hyperglycaemia and cardiovascular risk factors are implicated in the development of somatic and autonomic neuropathy and an improvement in these risk factors can reduce their rate of development and progression. There are currently no US Food and Drug Administration (FDA)-approved disease-modifying treatments for either somatic or autonomic neuropathy, as a consequence of multiple failed phase III clinical trials. While this may be partly attributed to premature translation, there are major shortcomings in trial design and outcome measures. There are a limited number of partially effective FDA-approved treatments for the symptomatic relief of painful diabetic neuropathy and autonomic neuropathy.

Clinical evidence and mechanisms of growth factors in idiopathic and diabetes-induced carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is an entrapment neuropathy caused by compression and irritation of the median nerve, which travels through the carpal tunnel in the wrist. Increased fibrosis is a hallmark of the development and pathology of CTS. Different growth factors have been demonstrated to play a potential role in the development of CTS. Studies have described an increase in the expression of growth factors, including Transforming Growth Factor (TGF-β), Vascular Endothelial Growth Factor (VEGF) and interleukins (growth factors for immune and inflammatory cells) in SSCT (sub-synovial connective tissue) in CTS patients. Additionally, SSCT fibrosis is also marked by increased activation of canonical TGF-β second messenger Smads, increased expression of downstream fibrotic mediators such as connective tissue growth factor (CTGF), increased production of collagen type I, II, III and IV, and decreased expression of matrix metalloproteinases. Anti-fibrotic such as anti-TGF treatment may prove beneficial in idiopathic patients, however, anti VEGF therapy can be successful in the diabetic CTS patients. The present review describes the clinical evidence stating the role of different growth factors in the development of fibrosis in idiopathic and diabetes induced CTS.

Sonographic assessment of carpal tunnel syndrome in diabetic patients with and without polyneuropathy

The objective of this study is to determine whether the cross sectional area (CSA) measurement of the median nerve at the wrist differ between carpal tunnel syndrome (CTS) in diabetic patients with and without diabetic polyneuropathy (DPN).This study included 44 patients with type II diabete millitus (DM) with CTS, 32 patients with CTS and DPN, 46 patients with idiopathic CTS, and 42 healthy subjects. Ultrasonographic measurement of the CSA of the median nerve was made at the level of the wrist, together with nerve conduction studies.The median CSA at the wrist was significantly larger in all patient groups compared with healthy subjects. The median nerve CSA was significantly larger in diabetic patients with CTS than patients with idiopathic CTS. The median nerve CSA at wrist was significantly smaller in patients with CTS and DPN compared with diabetic patients with CTS only.The median nerve CSA at the wrist was larger in diabetic patients with CTS than patients with idiopathic CTS and CTS with DPN. Median nerve CSA can help to differentiate between diabetic patients with CTS with and without DPN.

Prevalence of cold sensitivity in upper extremity nerve compression syndromes

This prospective observational study assessed the prevalence of cold sensitivity in patients with nerve compression using the Cold Intolerance Symptom Severity (CISS) questionnaire. One hundred patients (72 women, 28 men; mean age 59 years) with carpal tunnel syndrome ( n = 95) or cubital tunnel syndrome ( n = 5) were studied. Fifty-two patients reported symptoms of cold sensitivity with a mean CISS score of 50. Overall, significantly more women (58% vs. 36%) reported cold sensitivity with significantly worse CISS scores than men.

LEVEL OF EVIDENCE

IV.

Neurophysiological recovery 5 years after carpal tunnel release in patients with diabetes

INTRODUCTION

The long-term results of neurophysiological recovery after carpal tunnel release in patients with diabetes have not been studied.

METHODS

Thirty-five patients with diabetes and carpal tunnel syndrome (CTS) were matched with 31 patients without diabetes who had idiopathic CTS, and 27 and 30 patients, respectively, participated in this follow-up study. Nerve conduction results at 5 years were compared with previously published results at baseline and 1 year.

RESULTS

Significant neurophysiological improvement continued from 1 to 5 years after carpal tunnel release for patients with and without diabetes. However, wrist-palm sensory conduction velocity was still abnormal for 85% and 43% of patients with and without diabetes, respectively. Although diabetes had an impact on 4 of 10 measured neurophysiological parameters, the influence of peripheral neuropathy seemed insignificant.

DISCUSSION

After carpal tunnel release, significant long-term neurophysiological improvement is possible for patients with diabetes, and it is not influenced by the presence of peripheral neuropathy. Muscle Nerve 56: E59-E64, 2017.

The investigation of association between IL-1Ra and ACE I/D polymorphisms in carpal tunnel syndrome

BACKGROUND

Carpal tunnel syndrome (CTS) is a common neurologic impairment caused by injury on the median nerve in the wrist, characterized by pain and loss of sensory. CTS usually occurs through three factors, such as a mechanical pressure on median nerve, immunologic changes, and oxidative stress. The aim of this study was to evaluate the influence of interleukin-1 receptor antagonist (IL-1Ra) and angiotensin-converting enzyme (ACE) I/D polymorphisms on the susceptibility of patients to the CTS.

METHODS

One hundred fifty-eight patients with CTS and 151 healthy controls were enrolled in this study. Each patient was analyzed according to diseases symptoms, such as gender, a positive Tinel's sign, a positive Phalen maneuver, disease sides, EMG findings, and clinical stage. We applied the polymerase chain reaction (PCR) to determine the polymorphisms of IL-1Ra and ACE I/D.

RESULTS

The statistically significant relation was not found between IL-1Ra, ACE I/D polymorphisms and CTS (respectively, P>.05; P>.05, OR: 1.51, CI: 0.82-1.61). Additionally, in the result of the statistical analysis compared with gene polymorphisms and clinical characteristics, we did not find any correlation (P>.05).

CONCLUSIONS

Our findings showed that there are no associations of IL-1Ra and ACE I/D polymorphisms with susceptibility of a person for the development of CTS. So, it means that these polymorphisms do not create a risk for the development of CTS. Further studies with larger populations will be required to confirm these findings in different study populations.

Elevated basal cytosolic calcium of endothelial cells influences the post-surgical outcome in diabetic CTS

Background Type 2 diabetes mellitus (T2DM)-induced neuropathy and ischemia-reperfusion post-surgery prolong carpal tunnel syndrome (CTS) pathology, but the effect of T2DM on the prognostic outcome of carpal tunnel (CT) release surgery needs to be investigated. Materials and methods A total of 64 individuals with CTS underwent CT release surgery. HbA1c levels identified their diabetic status. The individual prognostic outcomes were measured by nerve conduction velocity (NCV), amplitude, and latency. Measurement of [Ca²⁺]_c and reactive oxygen species (ROS) from isolated endothelial cells (ECs) revealed the oxidative burden of the normal and diabetic CTS phenotypes. Results CTS individuals with HbA1c > 7 showed decreased NCV (≈22 m/s) and amplitude (≈4.2 mV) with increased latency (≈6 ms), compared to groups with HbA1c ≤ 7. Further to CT release surgery, the reversal of the nerve conduction to normalcy was greatly influenced by the diabetic profile of the individuals. Our results showed elevated basal [Ca²⁺]_c and corresponding high cytosolic ROS in the ECs isolated from individuals with HbA1c > 7 compared to the diabetic and healthy control groups. Conclusion The individuals with diabetic index showed suboptimal neuronal performance pre- and post-CT release surgery. Oxidative stress mediated by high [Ca²⁺]_c and ROS of ECs dissipates to adjoining cells worsening the pathology of the untreated CTS.

Diabetes as a risk factor for carpal tunnel syndrome: a systematic review and meta-analysis

AIMS

To assess whether diabetes increases the risk of carpal tunnel syndrome and to estimate the magnitude of the association with Type 1 and Type 2 diabetes.

METHODS

We conducted a systematic search of PubMed, Embase, Web of Science, Scopus, Google Scholar and ResearchGate for articles published between 1950 and January 2015. A total of 36 studies (eight cross-sectional, 21 case-control and seven cohort studies) qualified for meta-analysis. We used a random-effects meta-analysis and assessed heterogeneity and publication bias.

RESULTS

The pooled odds ratio of 25 studies (including a total of 92 564 individuals) that reported unadjusted estimates for the association between diabetes and carpal tunnel syndrome or carpal tunnel release was 1.97 (95% CI 1.56-2.49). The pooled odds ratio of 18 case-control or cohort studies consisting of >37 million individuals that reported estimates after controlling for potential confounders was 1.69 (95% CI 1.45-1.96). The association did not differ for Type 1 and Type 2 diabetes. Furthermore, there was no publication bias.

CONCLUSION

This meta-analysis suggests that both Type 1 and Type 2 diabetes are risk factors for carpal tunnel syndrome.

Enhanced expression of Wnt9a in the flexor tenosynovium in idiopathic carpal tunnel syndrome

This study aimed to clarify the association between abnormal Wnt signaling and the cause of idiopathic carpal tunnel syndrome (ICTS) and whether an association exists between Wnt signaling and cell proliferation in the flexor tenosynovium. The subjects included nine patients with ICTS; the controls were nine patients with distal radius fractures without any symptoms of carpal tunnel syndrome. We extracted mRNA from the flexor tenosynovium and compared the expression levels of genes encoding 17 types of Wnt in both subjects and controls via quantitative real-time polymerase chain reaction (PCR). Expression levels of factors involved in cell proliferation, such as estrogen-responsive finger protein, epidermal growth factor receptor, heparin binding-epidermal growth factor-like growth factor, insulin-like growth factor-1, and vascular endothelial growth factor (VEGF) were also measured using quantitative real-time PCR. In addition, we compared the Wnt and MIB-1 protein expression levels to clarify the effect of Wnt on cell proliferation. Quantitative real-time PCR revealed significantly greater expression of the gene encoding Wnt9a in subjects with ICTS than in controls and also revealed a positive correlation between the expression of genes encoding Wnt9a and VEGF in subjects with ICTS. Quantitative evaluation using immunohistochemical staining also indicated more marked Wnt9a expression in subjects than in controls. However, there was no relationship between the expression of Wnt9a and the cell proliferation index MIB-1. These results indicate that Wnt9a expression is enhanced in ICTS and that Wnt9a may be involved in VEGF expression in ICTS.

Autophagy in the posterior interosseous nerve of patients with type 1 and type 2 diabetes mellitus: an ultrastructural study

AIMS/HYPOTHESIS

We addressed the question of whether the autophagy pathway occurs in human peripheral nerves and whether this pathway is associated with peripheral neuropathy in diabetes mellitus.

METHODS

By using electron microscopy, we evaluated the presence of autophagy-related structures and neuropathy in the posterior interosseous nerve of patients who had undergone carpal tunnel release and had type 1 or type 2 diabetes mellitus, and in patients with no diabetes (controls).

RESULTS

Autophagy-related ultrastructures were observed in the samples taken from all patients of the three groups. The number of autophagy-associated structures was significantly higher (p < 0.05) in the nerves of patients with type 1 than type 2 diabetes. Qualitative and quantitative evaluations of fascicle area, diameter of myelinated and unmyelinated nerve fibres, the density of myelinated and unmyelinated fibres and the g-ratio of myelinated fibres were performed. We found degeneration and regeneration of a few myelinated axons in controls, and a well-developed neuropathy with the loss of large myelinated axons and the presence of many small ones in patients with diabetes. The pathology in type 1 diabetes was more extensive than in type 2 diabetes.

CONCLUSIONS/INTERPRETATION

The results of this study show that the human peripheral nerves have access to the autophagy machinery, and this pathway may be regulated differently in type 1 and type 2 diabetes; insulin, presence of extensive neuropathy, and/or other factors such as duration of diabetes and HbA1c level may underlie this differential regulation.

Morphological changes of the peripheral nerves evaluated by high-resolution ultrasonography are associated with the severity of diabetic neuropathy, but not corneal nerve fiber pathology in patients with type 2 diabetes

Aims/Introduction

To evaluate the morphological changes of the median and posterior tibial nerve using high-resolution ultrasonography, and the corneal C fiber pathology by corneal confocal microscopy in type 2 diabetic patients.

Materials and Methods

The cross-sectional area, hypoechoic area and maximum thickness of the nerve fascicle of both nerves were measured by high-resolution ultrasonography in 200 type 2 diabetic patients, stratified by the severity of diabetic neuropathy, and in 40 age- and sex-matched controls. These parameters were associated with corneal C fiber pathology visualized by corneal confocal microscopy, neurophysiological tests and severity of diabetic neuropathy.

Results

The cross-sectional area, hypoechoic area and maximum thickness of the nerve fascicle of both nerves in patients without diabetic neuropathy were larger than those in control subjects (P < 0.05 to P < 0.001), and further increased relative to the severity of neuropathy (P < 0.0001). All morphological changes of both nerves were negatively associated with motor and sensory nerve conduction velocity (P = 0.01 to P < 0.0001), and directly associated with 2,000-Hz current perception threshold (P = 0.009 to P < 0.001). The significant corneal C fiber pathology occurred before developing the neuropathy, and deteriorated only in patients with the most severe neuropathy. The association between the morphological changes of both nerves and corneal C fiber pathology was poor.

Conclusions

The morphological changes in peripheral nerves of type 2 diabetic patients were found before the onset of neuropathy, and were closely correlated with the severity of diabetic neuropathy, but not with corneal C fiber pathology.