Transfer of the Intercostal Nerves to the Radial Nerve Branch Innervating the Long Head of the Triceps Muscle for Elbow Extension.

BACKGROUND

Transfer of intercostal nerves to the radial nerve branch innervating the long head of the triceps muscle for elbow extension is indicated in patients with traumatic brachial plexus palsy that is either the pan-plexus type or C5-C7 palsy with no triceps muscle function. The procedure aims to restore triceps muscle function through the use of the intercostal nerves, which are expendable nerves, as donors.

DESCRIPTION

The procedure is performed by first identifying the third to fifth intercostal nerves and coaptating them to the radial nerve branch innervating the long head of the triceps muscle. Three intercostal nerves are utilized because our previous study revealed that the use of 2 intercostal nerves resulted in poor outcomes. Additionally, 3 intercostal nerves are comparable in size to the recipient nerve. To identify the intercostal nerves, a curved incision is made over the sixth rib to the medial side of the arm, detaching the pectoralis major and minor from their distal insertion. The intercostal nerves are dissected from the inferior border of the third to fifth ribs. The radial nerve branch innervating the long head of the triceps muscle can be found distal to the teres major muscle as the first branch from the radial nerve via the same incision, at the medial side of the arm. Subsequently, the 3 intercostal nerves are coaptated to the radial nerve branch to the long head of the triceps muscle.

ALTERNATIVES

A deficit in active elbow extension may be deemed acceptable for certain patients who are amenable to utilizing gravity for performing such extensions. Nonoperative treatment could be contemplated for individuals falling into this category. Alternative surgical approaches may include nerve transfers utilizing other donor nerves, such as the ulnar or thoracodorsal nerves, or tendon transfer procedures.

RATIONALE

Although active elbow extension may not be the primary focus when treating brachial plexus injury, a lack of active elbow extension affects various daily activities, such as overhead tasks, the use of a walking aid, and reaching for objects on a table. Consequently, reanimating the muscle through the use of expendable donor nerves appears to be a suitable approach, particularly in young and active patients, aiming to restore function and enhance overall quality of life. Therefore, we recommend this procedure as an adjunct to other surgical interventions in active patients who would benefit from restored elbow extension to perform daily activities.

EXPECTED OUTCOMES

The procedure demonstrated satisfactory results in our prior study, consistent with findings from other studies that reported good results in 57% to 80% of patients. In our prior study, 65% of patients achieved favorable motor function (Medical Research Council grade 3 to 4), with no observed donor-site morbidity or respiratory complications. Factors negatively impacting satisfactory outcomes include being overweight (body mass index > 25 kg/m), the operative hand being the nondominant hand, and a prolonged duration from injury to surgery.

IMPORTANT TIPS

The procedure is recommended for patients presenting with pan-plexus palsy and upper-plexus palsy lacking triceps function. In the latter scenario, confirmation of the triceps muscle deficit is essential through serial examinations, electromyography, and intraoperative nerve stimulation.Previous rib fracture(s) do not serve as a contraindication for surgery. However, caution should be exercised in patients with a history of chest drain insertion because of the possibility of damage to the intercostal nerves.In cases of root avulsion injury, early surgical intervention is advisable.The use of fibrin glue may be considered to facilitate the coaptation of nerves.Patients undergoing this and other brachial plexus procedures should be thoroughly informed regarding the associated risks and benefits.The patient's commitment to participate in rehabilitation after surgery is imperative.

ACRONYMS AND ABBREVIATIONS

ICN = intercostal nerveMRC = Medical Research Council.