Work practices and histopathological changes in the tenosynovium and flexor retinaculum in carpal tunnel syndrome in women

Understanding carpal tunnel syndrome

ABSTRACT

Carpal tunnel syndrome (CTS) is an entrapment neuropathy affecting the median nerve. Prevalence is estimated at 4% to 5% of the population. A solid understanding of the anatomy, presentation, and diagnostics is key to efficient diagnosis and appropriate referral. Both surgical and nonsurgical interventions have led to improved clinical outcomes. Clinicians who have an in-depth knowledge of CTS symptoms and treatment options can prepare patients and streamline referrals for improved patient outcomes.

Carpal Tunnel Syndrome and Work

The incidence, age at presentation, disability and outcome after surgery were investigated in 327 consecutive women of working age presenting to a hand unit with carpal tunnel syndrome. Two hundred and seventeen were working, 55 of these in repetitive occupations. One hundred and ten were not in employment. All three groups had similar mean ages (around 46 years). On a population basis more women in non-repetitive occupations presented with carpal tunnel syndrome (220/100,000/year) than those in repetitive work (122/100,000/year) or those not working (129/100,000/year), and more were offered surgery (82% versus 67% for those in repetitive work and 58% for those not working). However, symptoms and disability; as assessed with the Michigan Hand Questionnaire and the SF-12, were less severe in working women. This study suggests that working in repetitive or non-repetitive occupations does not cause, aggravate or accelerate carpal tunnel syndrome. Working women may struggle to accommodate their symptoms compared to women who are not in employment causing more to seek help.

Work Practices and Histopathological Changes in the Tenosynovium in Carpal Tunnel Syndrome in Men

The aim of this prospective study was to assess whether the fibrous thickening of the carpal tunnel tenosynovium is influenced by working practices. We did this by investigating 50 men (58 hands) with idiopathic carpal tunnel syndrome, who were undergoing carpal tunnel decompression.

Occupational history, including vibration tool exposure, and presence of callosities and/or ingrained dirt on hands was recorded at the time of surgery. The flexor tenosynovium was biopsied, and assessed histologically by an observer blinded to occupational history.

Occupational group, age, weight and smoking showed no significant association with fibrous tenosynovial thickening. There was also no significant association between fibrous tenosynovial thickening and the presence of hand callosities/in-grained dirt or regular use of vibration tools. Thus no association was found between heavy occupational hand usage and the development of fibrous tenosynovial thickening around tendons within the carpal tunnel.

Gliding resistance of flexor tendon associated with carpal tunnel pressure: a biomechanical cadaver study

The purpose of this study was to investigate the effect of carpal tunnel pressure on the gliding characteristics of flexor tendons within the carpal tunnel. Eight fresh human cadaver wrists and hands were used. A balloon was inserted into the carpal tunnel to elevate the pressure. The mean gliding resistance of the middle finger flexor digitorum superficialis tendon was measured with the following six conditions: (1) as a baseline, before balloon insertion; (2) balloon with 0 mmHg pressure; (3) 30 mmHg; (4) 60 mmHg; (5) 90 mmHg; (6) 120 mmHg. The gliding resistance of flexor tendon gradually increased as the carpal tunnel pressure was elevated. At pressures above 60 mmHg, the increase in gliding resistance became significant compared to the baseline condition. This study helps us to understand the relationship between carpal tunnel pressure, which is elevated in the patient with carpal tunnel syndrome (CTS) and tendon gliding resistance, which is a component of the work of flexion. These findings suggest that patients with CTS may have to expend more energy to accomplish specific motions, which may in turn affect symptoms of hand pain, weakness and fatigue, seen commonly in such patients.

The relationship of obesity, age, and carpal tunnel syndrome: more complex than was thought?

Previous reports have shown that obesity is a risk factor for carpal tunnel syndrome (CTS). This study was performed to investigate whether this could be confirmed in a large, existing cohort of patients and to explore the interaction between age and body mass index (BMI) as risk factors. Demographic and clinical data were collected from 6096 patients referred to a subregional neurophysiology service for diagnosis of possible CTS. Patients presenting with their second CTS and those with diabetes or thyroid disease were excluded. Subjects in whom nerve conduction studies (NCS) confirmed CTS were compared with those having normal NCS. After exclusions, there were 4166 patients for analysis of whom 11 had incomplete data. A total of 2408 of 4155 proved to have definite neurophysiological evidence of CTS. Of these patients, 1150 were over the age of 63 years. Univariate and multivariate analyses demonstrated that increased BMI is a significant independent risk factor for CTS in patients under the age of 63 years, but is less important in older patients. Patients over the age of 63 years have a different pattern of risk factors for CTS than younger patients. This suggests that CTS in the elderly population may have different underlying pathogenetic mechanisms.