2. Which anatomical changes at the cubital tunnel could be associated with ulnar nerve entrapment? An ultrasonographic study

The aim of this study was to evaluate which anatomical changes detectable during the ultrasonography (US) exam, could be associated with the ulnar nerve entrapment (UNE) at the elbow. We enrolled all consecutive patients with “definite” diagnosis of monolateral UNE referred to our outpatients clinic with request for US examination of the affected elbow. The definite diagnosis was based on electrodiagnostic results. The US examination was carried out with static and dynamic scans, with particular attention for the anatomical changes of the nerve at the cubital tunnel of both arms. The ultrasonographist evaluated the presence of anatomical abnormalities (ganglions, osteophytes, osseous fragments and accessory muscles), the position of the nerve during the dynamic scans (normal, subluxation or luxation) and measured the cross sectional area (CSA) of the nerve at the site of the maximum enlargement. The logistic regression (SPSS 17) was carried out using the contralateral arm as control. We enrolled 44 patients (mean age 51 yo, range 21–83, SD ±15, 19 female). Among all the variables taken into consideration, the only one that correlated with the presence of UNE was the CSA. For every mmq of increased CSA the odds ratio for having UNE was 1.44. This preliminary data suggests that anatomical changes are not determinant for the presence of UNE.