Evaluation of the Incidence of Double Crush Syndrome in Patients with Carpal Tunnel Syndrome

This study aimed to determine the incidence of double crush syndrome in patients with carpal tunnel syndrome and evaluate the association of the severity of carpal tunnel syndrome, onset to diagnosis interval of carpal tunnel syndrome, gender and body mass index (BMI) with double crush syndrome. In this descriptive cross-sectional study, 105 patients (71 women) with carpal tunnel syndrome diagnosed via clinical manifestations and electrophysiologic criteria were selected randomly. The presence of cervical radiculopathy (C5, C6, C7 roots involvement) was characterized using electromyography-nerve conduction velocity (EMG-NCV) as double crush syndrome in these patients. The risk factors of double crush syndrome were evaluated. The incidence of double crush syndrome in patients with carpal tunnel syndrome was 41.9% (44 patients) which 9 of them (20.45%) were men and 35 (79.55%) were women. Among the men, 26.5%, and among the women, 49.3% showed double crush syndrome. None of the patients with body mass index of less than 20 kg/m2 had signs of double crush syndrome since 47.3% of patients with body mass index of more than 25 kg/m2 had double crush syndrome. Our study confirms that severe carpal tunnel syndrome and constant physical activity in involved limb increase the incidence of double crush syndrome. It also shows that the incidence of double crush syndrome in women is higher than men and higher body mass index could be a risk factor for double crush syndrome.