Prognostic Value of Nerve Ultrasound and Electrophysiological Findings in Saturday Night Palsy.

BACKGROUND AND PURPOSE: We report on the prognostic role of the cross-sectional area (CSA) enlargement and conduction block (CB) in radial neuropathy (Saturday night palsy [SNP]).

METHODS

Reference CSA values were defined in 30 healthy subjects. Twenty-four patients with SNP underwent evaluation (Thessaloniki Hypesthesia Score [THS], Medical Research Council [MRC], ultrasound, electrophysiology). All patients were followed up 3 months after initial presentation.

RESULTS

During initial evaluation, 13 patients showed pathological CSA (pCSA) and 11 normal CSA (nCSA). Fourteen patients showed conduction block (pCB) and 10 showed no conduction block (nCB). The site of lesion was recognized in 11 patients in the spiral groove, in 8 patients in the distal main trunk, just before the division to motor and sensory branch, while 5 patients showed a double site of lesion (spiral groove and supinators' canal). During follow-up, the pCSA group showed a mean MRC score of 2.8 (SD ± .7) and a THS of 1.8 (SD ± .4), while the nCSA group showed a mean MRC score of 4.1 (SD ± .9) and a THS of .7 (SD ± .3) (P < .001) (Table 4). On the other hand, the pCB group showed a mean MRC score of 3.7 (SD ± 1.1) and a THS of 2.7 (SD ± .9), and the nCB group showed a mean MRC score of 4.2 (SD ± 1.2) and a THS of 1.7 (SD ± .9) (P = .355, P = .013, respectively).

CONCLUSIONS

The CSA enlargement, but not the CB, seems to have a negative prognostic role in patients with SNP.