[Assessment of the effects of surgical treatment options for cubital tunnel syndrome on the ulnar nerve by USG and EMG].

OBJECTIVES

The morphology and functional results of the ulnar nerve were evaluated in patients treated with simple decompression and anterior subcutaneous transposition due to the diagnosis of cubital tunnel syndrome.

PATIENTS AND METHODS

Thirteen elbows of 13 patients (8 males, 5 females; mean age 41 years; range 25 to 56 years) treated with simple decompression and anterior subcutaneous transposition due to the diagnosis of cubital tunnel syndrome were investigated. The involvement was on the dominant side in six patients. There was a 25° cubitus valgus deformity in one patient. No significant etiologic cause was found in the other patients. Seven patients were treated with anterior subcutaneous transposition and six with simple decompression. During the follow-ups, the atrophy magnitude, the new pressure areas and the intrinsic structure of the nerve tissue along the ulnar nerve path were evaluated by using soft tissue ultrasonography (USG). The flow rate of the artery supplying the ulnar nerve by Doppler mode USG and ulnar nerve conduction rate by electromyography (EMG) were assessed. Functional results were evaluated according to the Akahori's criteria and the modified Bishop scoring system. The average follow-up time was two years (range 12-44 months).

RESULTS

In the Doppler USG examination, no arterial blood flow supplying the ulnar nerve was found in five of seven patients who underwent anterior transposition. A blood flow decrease of approximately 20 cm/s was found in two patients. A blood flow decrease of 10 cm/s on average was found in six patients who underwent simple decompression. There was a significant difference between the two groups (p<0.05). The control EMG revealed an increase of 9 m/s in the ulnar nerve conduction rate in the transposition group (p>0.05) and an increase of 17 m/s in the simple decompression group compared to the preoperative values (p<0.05). In seven patients who underwent anterior subcutaneous transposition, five excellent and two good results and an average of 8.2 points were achieved according to the Akahori's criteria and the modified Bishop scoring system, respectively. In six patients who underwent simple decompression, five excellent results, and one good result and an average of 8.1 points were achieved according to the Akahori's criteria and the modified Bishop scoring system, respectively. There was no statistically significant difference between functional results of both surgical techniques (p>0.05).

CONCLUSION

Although the functional results of the cubital tunnel syndrome surgery are good, it must be noted that the blood supply to the nerve may be distorted, especially during anterior transposition. If there is no additional requirement, simple decompression may be considered as the first option.