A novel dual nerve transfer for restoration of shoulder function and sensory recovery of the hand, in patients with C567 traumatic root avulsion of the brachial plexus

OBJECTIVE

The objective of our study is to determine the anatomical viability in cadavers of a novel doble nerve transfer technique for simultaneous reanimation of shoulder abduction and sensory recovery of the hand, in patients with brachial plexus injuries sustaining a C5-C6-C7 roots avulsion. These new transfers should be complemented in the clinical setting with other classic nerve transfers, i.e.: (1) a spinal accessory to suprascapular for shoulder abduction and stability, (2) ulnar nerve fascicles to the biceps branches of the musculocutaneous for elbow flexion, and (3) intercostal to triceps branches for elbow extension.

METHODS

The proposed surgical technique includes (1) transferring motor fascicles of the median nerve (MNF), as donors to the axillary nerve (AN), and (2) the whole medial antebrachial cutaneous nerve (MACN) to the lateral contribution (sensory) of the median nerve (LCMN), both without the use of interposed nerve grafts. These techniques were performed in eight cadaveric upper extremities. Analyzed variables were: donor and receptor nerves diameter, length and distance of donor and receptors nerves, and axonal count.

RESULTS

The mean distance between the MNF and its point of coaptation to the AN was 19 mm. The average length of each one of the MNF, after distal dissection, was 46.5 mm. The average diameter of each fascicle of the median nerve at its coaptation point with the axillary nerve was 0.8 mm, while the average diameter of the latter was 3.9 mm. The average distance between the MACN and its point of coaptation to the LCMN, was 16.5 mm. The average diameter of the MACN and the LCMN at their point of coaptation, were 2.7 mm and 3.5 mm, respectively.

CONCLUSION

These nerve transfers are anatomically viable and could be a complement for other currently used techniques that can be employed in severely injured C567 brachial plexus patients.

Vascularization of the lateral and medial antebrachial cutaneous nerves by cutaneous perforator arteries: An anatomical study

The forearm is an interesting donor site for non-vascularized nerve grafts, especially hand surgeons. Very few studies have described the use of the lateral and medial antebrachial cutaneous nerves (LABCN and MABCN, respectively) as vascularized nerve grafts (VNGs). The aim of this anatomical study was to analyze the characteristics and vascularization of these nerves to describe new potential donor sites for VNGs. Twelve forearms were dissected from fresh cadavers injected with red latex. The number of terminal branches, lengths, and proximal and distal diameters of both the LABCN and MABCN were studied. An anatomical description of the cutaneous perforator arteries from the radial and ulnar arteries that vascularized the nerve was also recorded: number of perforators, length, type of perforator (septo- or musculocutaneous), and location within the forearm (proximal, middle, and distal third). In over 80% of the specimens, the cutaneous perforator arteries from the radial and ulnar artery vascularized the LABCN and the MABCN, respectively. These arteries, found mostly in the proximal third of the forearm, had diameters >0.5mm. Most of them came from the radial and ulnar arteries (for LABCN and MABCN vascularization, respectively). In over 75% of the specimens, the nutrient arteries of both nerves also vascularized the superficial veins and the skin. We found that these nerves are vascularized by perforators arteries, which also participate in vein and skin vascularization. Altogether, this anatomical study shows that reconstructive surgeons could use new VNGs based on the perforator artery of the forearm.

Anatomy of the posterior branch of the medial antebrachial cutaneous nerve: A cadaveric study

PURPOSE

The posterior branch of the medial antebrachial cutaneous nerve (MACN) is at risk to be damaged during cubital tunnel surgery. The purpose of this study was to identify the location of the posterior branch of the MACN (PBMACN) in relation to surgical landmarks pertinent in cubital tunnel surgery.

METHODS

We performed an anatomical study on 20 limbs from 13 fresh cadavers. The nerve was dissected from 10cm proximal to 10cm distal of the medial epicondyle. We measured the distance between the nerve and the medial epicondyle, and also the distance separating the PBMACN from the ulnar nerve passage between the two heads of the flexor carpi ulnaris. Measurements were performed with the elbow at 45° and 90° of flexion, as well as in full pronation and supination.

RESULTS

After its emergence from the main trunk of the MACN, the posterior branch ran anteriorly to the medial epicondyle, taking an oblique direction toward the ulnar shaft. The PBMACN was in average 2.53cm under the medial epicondyle when the elbow was flexed at 45°, and 2.96cm when the elbow was flexed at 90°. Average distance between the PBMACN and the penetrating point of the ulnar nerve within the flexor carpi ulnaris was 1.54cm when the elbow was flexed at 45°, and 1.62cm when the elbow was flexed at 90°. Pronation and supination positions of the forearm did not significantly modify our measurements.

CONCLUSIONS

Understanding the position of MACN posterior branch during ulnar nerve release surgery at the elbow may help in preventing iatrogenic injury. According to our measurements, incision and superficial dissection anterior to the medial epicondyle or distal to the ulnar nerve penetrating point between the two heads of the flexor carpi ulnaris should be avoided or done with an elbow flexed at 90°.

Surgical outcomes of neurogenic thoracic outlet syndrome based on electrodiagnostic tests and QuickDASH scores

In total, 665 of 680 (97%) patients with neurogenic thoracic outlet syndrome (NTOS) improved with conservative treatment. The remaining (3%) patients (15 of 680 patients) did not benefit after 3 months of conservative treatment and were referred for transaxillary first rib resection. We retrospectively compared the preoperative and postoperative (3 months) electromyelography and Quick Disability of Arm, Shoulder and Hands results of operated NTOS patients. Three of the 15 (20%) patients in the surgical cohort were male, with a median age of 25.3 ± 4.16 years, and the other 12 patients (80%) were female with a median age of 31.9 ± 9.48 years. Two of the 15 patients had a cervical rib, 4 of the 15 patients had an extension of the C7 transverse process, and 14 of the 15 patients had a cervical band. These bone and tissue abnormalities were removed in addition to the first rib resection and division of the subclavius muscle and the anterior scalenus and middle scalenus muscles. QuickDASH scores were 1062 preoperatively and 549 postoperatively. The latency of the median F-wave was significantly prolonged on the affected side compared to the unaffected side preoperatively (p = 0.015). There was no remarkable difference in the latency of ulnar F-waves between sides (p = 0.246). The medial antebrachial cutaneous nerve response values increased significantly postoperatively (p < 0.0001). Significant increases in ulnar sensory nerve action potential values amplitude ratio (p < 0.003) and median nerve motor amplitudes (p < 0.0001) were also found postoperatively.

Determination of an ideal stimulation site of the medial antebrachial cutaneous nerve using ultrasound and investigation of the efficiency

OBJECTIVE

To determine an ideal stimulation site of the medial antebrachial cutaneous nerve (MACN) using ultrasound measurement and to compare the efficiency of the new stimulation site with the conventional stimulation site on the nerve conduction study.

METHODS

Both arms of 15 healthy participants were measured using ultrasound. The MACN was identified in the transverse view at each 0, 2, 4, 6, and 8 cm proximal sites from the medial epicondyle, and the distances to the median nerve and to the skin from the MACN were measured. The ideal stimulation site should be located at the level which can give the shortest distance from the skin and the longest distance from the median nerve in terms of volume conduction. To confirm the efficiency of the ideal site, we measured the amplitude of the MACN conduction study at the ideal site against one at the 4 cm proximal to the medial epicondyle (conventional site).

RESULTS

The ultrasound showed the ideal stimulation site for the MACN could be the elbow crease line. However, the nerve conduction study revealed that the amplitudes of the MACN were significantly larger at the 4 cm proximal to the medial epicondyle compared with ones at the ideal site.

CONCLUSION

The ideal stimulation site based on the ultrasound did not permit better stimulation site for the nerve conduction study of the MACN compared with the conventional site. Careful adjustment of the stimulation site on the basis of this study would contribute to an accurate conduction study of the MACN.

Nerve transfer strategies for spinal cord injury

BACKGROUND

Spinal cord injury (SCI) is a devastating condition, which beleaguers its victims with long-term health issues. Nerve transfer is a feasible option for restoration of critical limb function in patients with SCI that potentially improves independence and quality of life.

METHODS

This article delineates the general principles of nerve transfer and its specific application pertinent to SCI. The available nerve transfer strategies are described based on the targeted limb function, mostly involving critical upper extremity function. The role of nerve transfer for paraplegia, diaphragm reanimation, and bladder reinnervation is also discussed.

RESULTS

Nerve transfer offers several advantages over the traditionally used tendon transfer.

CONCLUSIONS

Nerve transfer does not require prolonged immobilization and provides greater functional gain for a given transfer. Reconstruction of several facets of upper limb function potentially can be performed in a single stage. The merits of nerve transfer deserve further study to evaluate its value for spinal cord injury in humans.