Loss of elbow flexion can be disabling and have a significant impact on daily function. It occurs as a result of an injury to the brachial plexus, the musculocutaneous nerve, or occasionally direct damage to the biceps and brachialis muscles. The most common mechanisms include obstetric injury, iatrogenic injury, trauma, infection, and congenital disorders such as arthrogryposis. In the setting of isolated an musculocutaneous nerve palsy, restoration of elbow flexion power and excursion without loss of upper extremity function is of paramount importance for patient functional status.

Surgical techniques to correct loss of elbow flexion are either nerve repairs/transfers or muscle transfers. Nerve repair with or without grafting, nerve transfers, or a combination of the 2 are commonly used in the treatment of traumatic brachial plexus injuries. Seddon used an ulnar nerve graft to connect the third and fourth intercostal nerves to the musculocutaneous nerve.1 Other well described nerve transfer donors include an ulnar nerve fascicle (Oberlin transfer) and/or a median nerve fascicle, intercostal nerves, and the phrenic nerve.2 However, when >18 months have elapsed since injury, muscle atrophy makes nerve repairs or transfers ineffective, necessitating a muscle transfer. In addition, nerve transfers may provide limb excursion but with diminished power.

For muscle transfers, one must consider the size, force vector, strength, and donor site morbidity of the transferred muscle. A variety of muscle transfers have been described for elbow flexion, including free gracilis transfer, pectoralis major transfer, pronator-flexor transfer (Steindler flexorplasty), triceps transfer, rectus femoris transfer and bipolar latissimus dorsi transfer. Pectoralis major transfer creates a nonphysiological vector with weaker and shorter elbow excursion. Triceps transfers naturally limit elbow extension after surgery.

Latissimus transfer for restoration of elbow flexion or extension was first reported in 1956 by Hovnanian3; he proposed a unipolar technique that freed the latissimus from its origins in the trunk. The latissimus dorsi transfer has the advantage of maintaining its neurovascular pedicle after transfer, obviating the need for neurotization. Since the insertion of the latissimus on the proximal humerus is in close proximity to the biceps origin, an ipsilateral unipolar transfer with maintained proximal attachment may result in ideal biomechanics.

Here, we describe our novel modification of the original unipolar latissimus dorsi transfer technique.3 Our technique encompasses 3 key concepts. The first addresses the critical distal anastomosis of the latissimus to the biceps tendon. Our weaving technique maintains desired rest-length tension and creates a robust repair that is less likely to fail. Second, tubularization of the latissimus muscle improves flexion strength by aligning the pull vector of muscle fibers linearly in the plane of flexion. Tubularization also improves cosmesis by more closely resembling the native biceps (now atrophied). Last, a skin paddle allows for a tension-free wound closure and promotes healing while acting as an indicator for underlying muscle viability. We believe this combination of techniques provides enhanced functional outcomes for patients undergoing this procedure by restoring strength, power, and joint excursion without compromise of upper limb functionality.

INDICATIONS/CONTRAINDICATIONS

A latissimus dorsi transfer is an option for patients with chronic loss of functional elbow flexion with no electromyography evidence of recovery, precluding a successful nerve repair or transfer when indicated, such as in the setting of significant biceps and/or brachialis atrophy. Occupational therapy and lifestyle modifications should be attempted before the patient is presented the option of undergoing surgery. Careful assessment of the latissimus preoperatively by physical examination and electromyography study should be performed as concomitant damage to the thoracodorsal nerve can occur in brachial plexus injury, resulting in a weak muscle unsuitable for transfer. The thoracodorsal nerve must be intact and the latissimus muscle should have close to full strength. To optimize the chances of obtaining a positive outcome, the patient must understand the postoperative rehabilitation process and convey a willingness to perform a dedicated program with close follow-up.

TECHNIQUE Setup/Superficial Exposure

Following general anesthesia induction, the patient was placed in the lateral decubitus position on an inflatable bean bag positioner with the operative side facing the ceiling. The patient’s upper extremity and hemithorax were prepped and draped in standard sterile fashion. An incision was made along the anterior border of the latissimus muscle. An elliptical skin paddle was formed over the muscle at its lateral border, ~5 cm at its widest point and 13 cm in length, tapering at both ends. The adjacent skin and subcutaneous tissue were elevated as full-thickness flaps off the fascia overlying the muscle (Fig. 1A).

FIGURE 1:

A, A skin paddle is developed overlying the lateral edge of the latissimus dorsi, ~5 cm in width at its widest point and ~13 cm in length, tapering towards its proximal and distal ends. B, The latissimus dorsi is released at its origin along the paravertebral space and iliac crest and elevated.

Deep Exposure

The anterior edge of the latissimus was found and a plane was developed bluntly between the muscle and underlying serratus anterior. The origin of the latissimus was then sharply released from the paravertebral space and iliac crest (Fig. 1B). Dissection was continued up proximally towards the axilla and the insertion of the latissimus on the proximal humerus. As the flap was gradually elevated and the plane was developed between the flap and the serratus, the serratus branch from the thoracodorsal pedicle was visualized heading into the serratus anterior muscle near the insertion of the latissimus at the axilla—the thoracodorsal pedicle was then subsequently identified associated with this branch. The serratus branch of the thoracodorsal artery as well as the circumflex scapular artery were identified, tied off, and divided. The neurovascular pedicle containing the thoracodorsal artery, vein, and nerve was then gently dissected proximally becoming the subscapular artery, toward the origin off the axillary artery. The latissimus was subsequently freed and mobilized on its pedicle and proximal humeral attachment. An axillary subcutaneous pocket was then developed to function as a skin bridge over the proximal muscle attachment and allow anterior passage of the distal muscle and overlying skin paddle without kinking of the pedicle.

A curvilinear, longitudinal incision was then made over the anterior aspect of the arm, over the biceps muscle and extending to the antecubital fossa. The skin and subcutaneous tissues were elevated, and a subcutaneous tunnel was established bluntly at the axilla between the anterior and posterior wounds. The myocutaneous flap was passed through this tunnel without kinking the neurovascular pedicle (Figs. 2A, B). Two deep drains were then placed in the posterior wound before closure.

FIGURE 2:

A, A subcutaneous axillary pocket is developed which forms a skin bridge between the anterior and posterior incisions. The myocutaneous flap is passed through this subcutaneous tunnel in the axilla from the posterior incision to the anterior arm. B, A detailed view of the posterior subcutaneous tunnel, demonstrating the uncompromised position of the neurovascular pedicle (arrow). The teres major is visualized just medial to the subcutaneous tunnel. C, Nonabsorbable braided polyester sutures are placed in the deep edges of the latissimus dorsi to tubularize the flap and more closely resemble the native biceps muscle. D, Two distal tails are created from the latissimus and are tubularized by a running 2-0 braided polyester suture. The tails are then woven through 3 longitudinal incisions made in the distal biceps and its tendon.

Reconstruction

The patient was repositioned supine by inflating the bean bag and shifting the torso towards the center of the operating table before deflating the bean bag again. The anterior incision was carried distally across the antecubital fossa to expose the distal aspect of the biceps tendon. Full-thickness skin flaps were elevated on either side of the incision. Three small incisions were then made in the distal biceps muscle at the myotendinous junction and through the distal biceps tendon. The distal free end of the latissimus was then trimmed back to provide physiological rest-length tension when the anastomosis was to be complete. This provided appropriate excursion, while recreating optimal length for developing power of the transferred muscle. The distal end was then divided in half to form 2 tails which were also tubularized by a running double-core, criss-crossing 2-0 polyester suture. This tubularization is safe because of the internal blood flow of the muscle with a prominent descending branch and a transverse branch that originates proximal in the muscle.

The bulk of the latissimus dorsi muscle was folded in half onto itself and along its deep surface was sutured into a tubular shape to resemble the biceps muscle belly (Fig. 2C). With the elbow in 90 degrees of flexion, the 2 tails of the distal latissimus were woven through the 3 incisions in the distal biceps and tendon at least 3 times and secured with #2 Fiberwire sutures after each weave (Arthrex, Naples, FL) (Fig. 2D). Any excess peripheral distal muscle was trimmed and removed after the transfer was completed. The skin flap of the pedicle was then sutured to the surrounding skin as the entire anterior wound was closed in layers (Fig. 3A).

FIGURE 3:

A, The proximal and distal skin edges of the anterior arm are brought together and the pedicle skin flap is subsequently sutured to the surrounding skin. Patient’s arm in flexion postoperatively (B) at 3 weeks and (C) at 3 months with uncomplicated, tension-free skin healing and excellent cosmesis resembling the patient’s native biceps. The patient was already able to manipulate the weight of a water bottle at 3 months postoperatively.

Rehabilitation

The patient’s arm was placed in a bulky dressing with medial/lateral splints of the elbow at 90 degrees of flexion in full supination immediately postoperatively. Two weeks later, the dressing and splint were removed for a wound check and the patient was transitioned to a posterior thermoplastic elbow splint in 90 degrees of elbow flexion. Functional hand use and gentle shoulder pulley exercises without strengthening were started by the patient at this stage. One month postoperatively, the sling and splint were discontinued and rehabilitation focused on retraining the muscle to flex the elbow and supinate the forearm. Strengthening began at 3 months when the wound was mature and the flap well-incorporated.

EXPECTED OUTCOMES

Berger and Brenner4 reported on 22 cases of unipolar latissimus transfer and found that functional elbow flexion with an average up to 10 to 15 kg of force was ultimately possible. In our experience of 4 male patients with varied underlying pathologies, recovery close to full range of motion of the elbow occurred between 8 and 12 weeks. They are able to lift ~1 kg of weight with functional elbow motion by 3 months, and can ultimately lift up to 2 to 3 kg or greater at 1 to 2 years postoperatively. At 3 weeks postoperatively, active shoulder flexion to 100 degrees, passive shoulder flexion to 120 degrees, active elbow extension to 40 degrees, and active elbow flexion to 110 degrees can be seen. By 3 months, patients are expected to flex, supinate, and pronate while holding a 1 to 2 lb weight. By 6 months, flexion at the elbow with 25 lbs force can be expected. Overall, these range of motion findings align with a previous case series on 17 patients with latissimus dorsi myocutaneous flap transfers that averaged 111 degrees of elbow flexion.5

Our modification of Hovnanian described unipolar latissimus dorsi muscle transfer adds weaving of the muscle’s aponeurotic tissue to the biceps brachii insertion, tubularization of the donor muscle, and a skin paddle for improved cosmesis. The pedicled donor muscle obviates a need for vascular anastomoses. Although repairing muscle to tendon can be technically challenging, our weaving technique provides a reliable means to create a strong, robust repair that allows the maintenance of tension and minimizes the risk of stretching out or late rupture. Tubularization better aligns biomechanics of the transfer to the native biceps. The skin pedicle ultimately assists in producing a cosmetically appealing result, as was seen in our patient who continued to have excellent healing at 3 weeks and 3 months postoperatively (Figs. 3B, C).

COMPLICATIONS

The primary complication to avoid in any pedicled muscle transfer is disruption to the donor’s blood supply. Kinking of the neurovascular pedicle can occur due to undue tension from fascial bands or its new trajectory during the transfer process. It is important to transfer the donor muscle anteriorly through its subcutaneous tunnel without twisting the pedicle and to release any fascial restrictions. A smaller tunnel helps maintain alignment but widening the subcutaneous tunnel is always an option if the flap proves difficult to pass anteriorly.

While muscle transfers may fail due to inadequate fixation, we believe our weaving technique to the radial tubercle strengthens fixation. However, additional aponeurotic tissue can be further fixed to nearby tissues such as forearm fascia and the lacertus fibrosis to increase fixation.

An insufficient skin island may be found upon closing such that the wound is not tension free; it is best to assess the contralateral arm beforehand to measure ideal skin island dimensions. If the skin island is not large enough, a staged split thickness skin graft may be considered.

CONCLUSIONS

This case reviews a technique of modified unipolar latissimus dorsi muscle transfer for restoration of elbow flexion in the setting of a musculocutaneous nerve palsy. Our technique involves a weaving pattern for fixture of the latissimus to the biceps tendon to allow for ideal tension, tubularization of the muscle to recreate biceps anatomy, and a skin paddle to promote tension-free wound healing. Our patient showed sufficient strength and range of motion for daily life by 6 months that persisted for 6 years.

REFERENCES 1. Seddon HJ. Nerve grafting. Ann R Coll Surg Engl. 1963;32:269–280. 2. Oberlin C, Béal D, Leechavengvongs S, et al. Nerve transfer to biceps muscle using a part of ulnar nerve for C5-C6 avulsion of the brachial plexus: anatomical study and report of four cases. J Hand Surg Am. 1994;19:232–237. 3. Hovnanian AP. Latissimus dorsi transplantation for loss of flexion or extension at the elbow; a preliminary report on technic. Ann Surg. 1956;143:493–499. 4. Berger A, Brenner P. Secondary surgery following brachial plexus injuries. Microsurgery. 1995;16:43–47. 5. Kawamura K, Yajima H, Tomita Y, et al. Restoration of elbow function with pedicled latissimus dorsi myocutaneous flap transfer. J Shoulder Elbow Surg. 2007;16:84–90.