Nerve transfer to deltoid muscle using the intercostal nerves through the posterior approach: an anatomic study and two case reports.
OBJECTIVE
To evaluate the feasibility of restoring the deltoid function in patients with C5 through C7 root avulsion injuries by transferring 2 intercostal nerves to the anterior branch of the axillary nerve through a posterior approach. The preliminary results of the clinical application of this procedure also are reported.


METHODS
The study was performed on 10 fresh cadavers. The lengths of the third, fourth, and fifth intercostal nerves from the costochondral junction to the midaxillary line were recorded. The distance from the pivot point at the midaxillary line to the anterior branch of the axillary nerve was recorded as the tunnel length. All histomorphometric measurements of the axon number were recorded. Based on the anatomic study, the fourth and fifth intercostal nerves were transferred directly to the anterior branch of the axillary nerve in 2 patients.


RESULTS
The average distances from the costochondral junction of the third, fourth, and fifth intercostal nerves to the pivot points were 12, 15, and 16 cm, respectively. The average tunnel distances of the third, fourth, and fifth intercostal nerves were 11, 13, and 15 cm, respectively. The average numbers of myelinated nerve fibers of the third, fourth, and fifth intercostal nerves were 742, 830, and 1,353, respectively. At the 2-year follow-up evaluation the preliminary clinical results showed that the deltoid recovered against resistance (M4). The range of motion for shoulder abduction and external rotation were both 95 degrees in the first case and 105 degrees and 95 degrees , respectively, in the second case. Useful functional recovery was achieved and classified as a good result in both patients.


CONCLUSIONS
This anatomic study with 2 case reports supports the idea that transfer of 2 intercostal nerves to the anterior branch of the axillary nerve through the posterior approach could be an alternative method for reconstruction of the deltoid muscle in C5 through C7 root avulsion injuries.


METHODS
Therapeutic IV.
Malungpaishrope
Kanchai
K
Upper Extremity and Reconstructive Microsurgery Unit, Institute of Orthopaedics, Lerdsin General Hospital, Bangkok, Thailand. kanchai_hand@yahoo.com
Leechavengvongs
Somsak
S
Uerpairojkit
Chairoj
C
Witoonchart
Kiat
K
Jitprapaikulsarn
Surasak
S
Chongthammakun
Sukumal
S
D000293:Adolescent; D000328:Adult; D001369:Axons / Q000378:metabolism; D001917:Brachial Plexus / Q000293:injuries* / Q000601:surgery; D020516:Brachial Plexus Neuropathies / Q000601:surgery*; D002102:Cadaver; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007367:Intercostal Nerves / Q000033:anatomy & histology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation* / Q000601:surgery; D009413:Nerve Fibers, Myelinated / Q000378:metabolism; D016067:Nerve Transfer / Q000379:methods*