Table III.

Classification and treatment selection for cubital tunnel syndrome.

Types	Sensation	Movement	EMG	Imaging (X ray, CT or MRI)	Cubital tunnel indexa	Treatment
Type I	Ring and little finger numb, Tinel’s (+)	Conscious weakness, with or without action uncoordination	Normal	Normal	Normal	Movement control, rest, physiotherapy
Type II	Ring and little finger numb, Tinel’s (+)	Poor grip strength, decreased interosseous muscle strength or muscle atrophy	Motor and/or sensory nerve conduction velocity reduced	Normal	Normal	Ulnar neurolysis
Type III	Ring and little finger numb, Tinel’s (+)	Poor grip strength, decreased interosseous muscle strength or muscle atrophy	Motor and/or sensory nerve conduction velocity reduced	Osteoarthritis	Increased or decreased	Cubital tunnel expansion, ulnar nerve anterior transposition
Type IV	Ring and little finger numb, Tinel’s (+)	Conscious weakness, decreased interosseous muscle strength or muscle atrophy	Motor and/or sensory nerve conduction velocity reduced	Tumor, cysts, elbow deformity, post traumatic change	Normal	Targeted surgical treatment

^aDepth/width ratio when the cross-section rotates 30° forward through the Hueter line (normal range, 0.273±0.055).

EMG, electromyography; CT, computed tomography; MRI, magnetic resonance imaging.