Published online Sep 26, 2022. doi: 10.12998/wjcc.v10.i27.9628
Peer-review started: April 6, 2022
First decision: June 16, 2022
Revised: June 30, 2022
Accepted: August 21, 2022
Article in press: August 21, 2022
Published online: September 26, 2022
Injury to the accessory nerve (AN) can cause weakness or paralysis in the sternocleidomastoid (SCM) and trapezius muscles. Loss of motor function in the trapezius muscle leads to a painful and disabling condition. This syndrome is frequently observed after radical neck dissection. Current surgical treatment for trapezius paralysis mainly includes two strategies. The first is fascial muscle transplantation, which mainly includes static and dynamic transplantation. Another surgical strategy is nerve repair, which includes neurolysis, direct suture, and nerve grafting.
A key point in nerve transplantation for the treatment of trapezius paralysis is finding the appropriate donor nerves. It has been reported that trapezius muscle function can be restored by directly transplanting a nerve in the upper trunk of the brachial plexus and suturing the distal end of the AN. According to Tubbs's anatomical study, the suprascapular nerve (SCN) could be used as a donor nerve for nerve repair.
To further explore the feasibility of transplanting the suprascapular nerve as a donor nerve to the accessory nerve to restore trapezius muscle function, we conducted exploratory studies of both human anatomy and clinical application.
Based on the dissection of ten sides of cadavers, the length of the SCN (n = 10) from the origin of the brachial plexus (a point) to the scapular notch (b point) and the distance of the SCN from the origin point (a point) to the point (c point) where the AN entered the border of the trapezius muscle were measured. The length and branches of the AN (n = 10) in the trapezius muscle were measured. A female patient aged 55 years underwent surgery for partial SCN to AN transfer. One-third of the diameter of the SCN was cut off, and combined epineurial and perineurial sutures were applied between the distal end of the cut-off fascicles of the SCN and the proximal end of the AN without tension. Both subjective and objective evaluations were performed before, three months after, and nine months after surgery.
The whole length of the AN in the trapezius muscle was 16.89 cm. The average numbers of branches distributed in the descending, horizontal and ascending portions were 3.8, 2.6 and 2.2, respectively. The diameter of the AN was 1.94 mm at the anterior border of the trapezius. The length of the suprascapular nerve from the origin of the brachial plexus to the scapular notch was longer than the distance of the suprascapular nerve from the origin point to the point where the accessory nerve entered the upper edge of the trapezius muscle. The amplitude of trapezius muscle electromyography indicated that both the horizontal and ascending portions of the trapezius muscle on the right side had better function than the left side nine months after surgery. The results showed that the right-sided supraspinatus and infraspinatus muscles did not lose more function than the left side.
Based on anatomical data and clinical application, partial suprascapular nerve-to-AN transfer could be achieved and may improve innervation of the affected trapezius muscle after radical neck dissection.
The suprascapular nerve could be used as a donor nerve for nerve repair according to the anatomical measurements and clinical findings in our study.