Trapezius Muscle Transfer

When the shoulder loses its ability to lift or rotate the arm due to nerve damage or severe muscle tears, one innovative surgical solution is the trapezius muscle transfer. This procedure helps restore movement and strength by rerouting part of the trapezius muscle—normally responsible for moving the shoulder blade—so it can assist other muscles that have lost function.

Why Consider Trapezius Transfer?

The trapezius transfer is typically considered when:

• Nerve repair surgery hasn’t succeeded (especially in brachial plexus injuries)
• The rotator cuff tear is too severe to repair directly
• Patients want to regain shoulder function without undergoing shoulder fusion or joint replacement, especially in younger individuals

This technique helps patients regain abduction (lifting the arm to the side) and external rotation (turning the arm outward), which are vital for reaching and functional arm use.

Understanding the Shoulder Problem

In conditions like brachial plexus injuries or massive rotator cuff tears, patients may lose control of shoulder muscles such as the deltoid, supraspinatus, and infraspinatus. This leads to weakness, poor range of motion, and sometimes complete inability to move the shoulder outward or upward.

When these critical muscles can’t function, the trapezius—especially the lower portion—can be re-routed to help replace that lost movement.

How the Procedure Works

There are several surgical variations, but the goal is the same: reroute the lower (or sometimes upper) trapezius muscle and attach it to a different part of the shoulder where function is missing.

Common Surgical Techniques:

1. Direct Lower Trapezius Transfer
   The lower trapezius is detached from the spine of the scapula and redirected to attach near the infraspinatus or other rotator cuff tendons. When possible, this is done without a graft, particularly in patients with brachial plexus palsy and preserved shoulder anatomy.
2. Graft-Augmented Transfer
   When a direct connection is too short, surgeons use a tendon graft—commonly an Achilles tendon allograft or a semitendinosus autograft—to extend the muscle and secure it to the humeral head. This is especially common in massive rotator cuff tears where long distances must be bridged.
3. Modified Trapezius Transfer
   In the modified technique, the trapezius is harvested with part of its bone attachment and extended with a folded fascia lata graft. This combined unit is anchored close to the deltoid insertion, allowing the transferred muscle to mimic natural shoulder motion.

Surgical Steps in the Modified Approach

• A U-shaped incision is made over the scapula and clavicle, and an S-shaped incision is placed on the upper arm.
• The trapezius muscle is carefully separated, along with a portion of bone from its natural attachment.
• A strip of tensor fascia lata (from the thigh) is folded and stitched to extend the length of the muscle.
• The extended trapezius is sutured near the deltoid insertion with the arm held in about 110° of abduction.

Recovery After Surgery

Recovery is a critical part of the success of trapezius transfer surgery:

1. Immobilization: The arm is placed in a cast or brace in an abducted position (~130°) for the first four weeks.
2. Early Movement: Hand and elbow exercises begin immediately; isometric muscle activation of the transferred muscle starts within the first week.
3. Rehabilitation: Around week 5, the arm is progressively brought back to normal position, and shoulder-specific exercises are introduced.
4. Strengthening: Over time, patients undergo resistance training to build strength in the transferred muscle.

What Patients Can Expect

The results of trapezius transfer can be very encouraging:

• Patients often see major improvements in the ability to lift the arm (abduction) and rotate it outward.
• In one study, patients with brachial plexus injury improved shoulder abduction from 37° to 116°, with reduced disability scores as well.
• For rotator cuff tear patients, there was a reported average gain of 37.5° in forward elevation and 34.3° in external rotation, helping many return to daily activities.

Benefits of the Procedure

• Restores functional movement in patients who had lost the ability to lift or rotate the shoulder
• Avoids joint replacement, especially useful in younger, active patients
• Can be performed with or without arthroscopy, depending on the approach

Potential Challenges

• Requires careful surgical planning to avoid injury to the accessory nerve
• In cases where grafts are used, there is a small chance of graft failure or donor site complications
• Muscle strain and over-tensioning can impact results, so surgeon expertise is key

Is It Right for You?

If you’ve had a severe shoulder injury or nerve damage and are unable to move your arm outward or upward, trapezius transfer may be a valuable option. The best candidates are those with preserved passive motion but poor active control due to nerve damage or irreparable muscle tears.

Conclusion

Trapezius muscle transfer is a promising surgical option for restoring shoulder motion when traditional nerve or muscle repairs are not possible. With the right patient selection and careful surgical technique, it offers meaningful improvement in quality of life, helping patients regain arm function and independence.

If you’re experiencing shoulder dysfunction and wondering if this surgery might help, consult your orthopedic surgeon for a detailed evaluation tailored to your condition.