Diagnostic value of ultrasonography versus electrodiagnosis in ulnar neuropathy

Figures & data

Table 1 Electrodiagnostic findings of patients

EDX findings	Criteria	Frequency (%)
Demyelination	Across-elbow NCV <49 m/second or difference between across-elbow NCV and forearm NCV >10 m/second	6 (18.8)
Conduction block	> 20% decrement in across-elbow CMAP amplitude	2 (6.3)
Axonal loss	Absence of ulnar SNAPs (fifth finger/DUC) or low-amplitude SNAP/CMAP or presence of denervation potentials (positive sharp wave and fibrillation) or chronic neurogenic motor-unit action potentials on EMG in ulnar innervated muscles	15 (46.7)
Demyelination + conduction block	Criteria of both categories	2 (6.3)
All above criteria	Criteria of all categories	7 (21.9)
Total		32 (100)

Abbreviations: CMAP, compound muscle action potential; DUC, dorsal ulnar cutaneous; EDX, electrodiagnosis; EMG, electromyography. NCV, nerve-conduction velocity; SNAPs, sensory nerve action potentials.

Table 2 Severity-grading classification of ulnar neuropathy based on electrodiagnostic findings

Severity	Criteria	Frequency (%)
Very mild	Only conduction block at elbow	3 (9.0)
Mild	Conduction block + demyelination	4 (12.2)
Moderate	Low amplitude in ulnar SNAPs + demyelination	1 (3.0)
Severe	Low-amplitude ulnar CMAP or absence of ulnar SNAPs (fifth finger/DUC) or presence of denervation potentials (PSW, fibrillation) or chronic neurogenic MUAPs in EMG in ulnar innervated muscles	24 (75.8)

Abbreviations: CMAP, compound muscle action potential; DUC, dorsal ulnar cutaneous; EMG, electromyography; MUAPs, motor-unit action potentials; PSW, positive sharp wave; SNAPs, sensory nerve action potentials.

Figure 1 Position of elbow in ultrasonography (from left to right) at level of medial epicondyle, 2 cm above it, and 2 cm below it, respectively.

Figure 2 Ulnar nerve cross-section area on ultrasonography.

Note: (A) At level of medial epicondyle (arrow, ulnar nerve; arrowhead, medial epicondyle; star, olecranon); (B) 2 cm above medial epicondyle (arrow, ulnar nerve; star, medial epicondyle); (C) 2 cm below medial epicondyle (arrow, ulnar nerve; stars, two heads of flexor carpi ulnaris muscle).

Table 3 Demographic characteristics of control and patient groups

Variables	Patient group (n=32)	Control group (n=34)	P-value
Mean age (95% CI), years	45.5 (35.16–55.96)	44.5 (34.13–54.93)	0.673
Sex (M:F)	20 (65%):12 (35%)	18 (58%):14(42%)	0.619
BMI (95% CI), kg/m^2	25.5 (22.1–28.9)	26.5 (23.1–29.9)	0.204
Hand dominance (R:L)	28 (87%): 4 (13%)	28 (88%): 4 (12%)	0.610
Side of complaint (R:L)	18 (56.3%):14 (43.7%)	—	—
Chronicity <6 weeks	8 (25%)	NA	NA
6–12 weeks	11 (35%)
>12 weeks	13 (40%)

Abbreviations: BMI, body-mass index; F, female; L, left; M, male; NA, not applicable; R, right.

Table 4 Distribution of ulnar nerve sonographic parameters between control and patient groups

Parameters	Patients, mean ± SD	Controls, mean ± SD	P-value	AUROC curve	Cutoff	Sen	Spe
CSAprox (mm^2)	7.47±1.43	7.52±1.55	0.913	0.492	NS	—	—
CSAdist (mm^2)	8.37±1.89	7.57±1.34	0.81	0.625	NS	—	—
CSAmed (mm^2)	12.68±3.96	8.27±1.74	<0.001	0.871	9 mm^2	84.4%	80.6%
CSAmed:prox	1.7±0.86	1.1±0.17	<0.001	0.870	1.312	75.0%	85.3%
CSAmed:dist	1.5±0.37	1.1±0.19	<0.001	0.872	1.185	87.5%	80.6%
CSAprox:dist	0.9±0.21	1±0.19	0.094	0.380	NS	—	—

Abbreviations: AUROC, area under receiver-operating characteristic; CSA, cross-sectional area; dist, distal to medial epicondyle; med, at the level of medial epicondyle; NS, not significant; prox, proximal to medial epicondyle; Sen, sensitivity; Spe, specificity.

Figure 3 Receiver-operating characteristic (ROC) curve for diagnostic value of ultrasonographic parameters in ulnar neuropathy.

Abbreviations: CSA, cross-sectional area; dist, distal to medial epicondyle; med, at the level of medial epicondyle; prox, proximal to medial epicondyle.