Restoration of Elbow Flexion With a Free Functional Gracilis Muscle Transfer in an Arthrogrypotic Patient Using a Motor Nerve to Pectoralis Major

Abstract

Background: Patients with arthrogryposis may exhibit inability to flex the elbow. A free functional gracilis muscle transfer (FFGMT) can be used to restore elbow flexion. In our search of the available literature, we have not seen any descriptions of using a motor branch to the pectoralis major as a donor nerve to establish elbow flexion. Methods: We performed an FFGMT for restoration of elbow flexion in an arthrogrypotic patient with no active elbow flexion, who had a Medical Research Council (MRC) muscle grade of 0. Results: We report our 4.5-year outcomes. After undergoing an FFGMT for elbow flexion, our patient was able to gain an MRC grade 4 and achieve an arc of motion of 25° to 140°. Conclusion: An FFGMT for elbow flexion may be performed successfully using a motor branch to the pectoralis major.

Introduction

Arthrogryposis is a term used to describe a group of disorders involving multiple, nonprogressive joint contractures present at birth. These contractures are due to neurogenic, myopathic, or connective tissue disorders.¹ Arguably, the most serious of these contractures is the inability to flex the elbow because these patients cannot exhibit independence due to their inability to self-feed and self-care for personal hygiene.

Multiple procedures have been described to produce active elbow flexion in patients with arthrogryposis, such as the latissimus dorsi transfer, pectoralis major transfer, triceps transfer, and Steindler flexorplasty.^2-11 In a PubMed search of the available literature, we could find 2 case series documenting the use of a free functional gracilis muscle transfer (FFGMT) in children with arthrogryposis when other aforementioned options were not available.^1,12

In these reports, donor nerves used for the FFGMT in arthrogrypotic cases consisted of the spinal accessory nerve, intercostal nerves, or fascicles of the ulnar nerve. To our knowledge, no patient with arthrogryposis has previously been treated with an FFGMT using a motor branch to the pectoralis major as the donor nerve to establish elbow flexion. We present our 4.5-year follow-up results of an FFGMT for the establishment of elbow flexion in a patient with arthrogryposis using a motor branch to the pectoralis major as a donor nerve.

Case Report

Patient Characteristics

The patient was a 5-year-old boy with arthrogryposis. On physical examination, he had no active left elbow flexion and minimal active right elbow flexion. He had intact left shoulder flexion and abduction, as well as full supination and pronation. He had good hand function with intact wrist and finger flexion and extension. He underwent greater than 1 year of preoperative occupational hand therapy to achieve maximum supple joint motion and reached a plateau of a passive range of motion of the left elbow of 10° to 135° (Figure 1).

Figure 1.

(a) Preoperative passive elbow extension and (b) preoperative passive elbow flexion.

Magnetic resonance imaging (MRI) was performed preoperatively to evaluate his latissimus dorsi and pectoralis muscles for possible transfer; however, they were found to be significantly atrophied bilaterally (Figure 2). An MRI of the gracilis muscles showed adequate muscle bulk with a healthy appearance (Figure 3). Thus, the patient was indicated for a contralateral lower extremity FFGMT to achieve active elbow flexion.

Figure 2.

Magnetic resonance imaging showing minimal pectoralis major and latissimus dorsi musculature.

Figure 3.

Magnetic resonance imaging showing adequate gracilis musculature.

Surgical Technique

A surgical incision was created over the anterior left upper extremity. With dissection of the anterior arm, the patient was found to have minimal remnants of biceps and brachialis musculature in the anterior compartment (Figure 4). The recipient site was prepared first to identify recipient vessels and motor nerve. The vascular pedicle and recipient nerve were mobilized as much as possible to obtain sufficient length for proper positioning of the transplanted muscle. The thoracoacromial pedicle and its vena comitantes were dissected and prepared for anastomosis.

Figure 4.

Anterior arm dissection showing minimal to no biceps or brachialis musculature.

In our field of dissection, we identified 2 nerves to the remnants of pectoralis major muscle. Despite the poor muscle quality of the pectoralis major visualized on preoperative MRI, both of these nerves were found to generate strong contracture of the pectoralis major muscle remnants when stimulated. These nerves were branches of the lateral pectoral nerve. Thus, a decision was made to use one of these branches as our donor nerve.

Next, our dissection was extended proximally to the distal third of the clavicle and distally to the level of the radial tuberosity to prepare the gracilis attachment sites. Typically, we use tenorrhaphy to the biceps tendon proximally and distally in a Pulvertaft weave fashion; however, no biceps muscle or tendon was available in this patient. Therefore, it was decided to anchor the gracilis tendon to the bone at the clavicle and the radial tuberosity.

At this point, we began our gracilis harvest. Our comprehensive surgical technique for the dissection of the gracilis muscle for free functional muscle transfer has been described previously.^13-15 An incision was made over the right thigh, and the gracilis was identified after release of the skin and subcutaneous tissue. Once the tendon was identified, the skin at the proximal third of the gracilis was harvested. The fasciae overlying the sartorius and adductor muscles were also resected with gracilis fascia as well as a skin paddle of 10 cm length and 4 cm width.

The distance from the gracilis origin to the musculotendinous junction was marked every 5 cm with a silk suture to mark resting length in maximum leg abduction and knee extension. Furthermore, the skin paddle was anchored to the fascia of the gracilis using suture to avoid damage to the perforating vessels via shear forces. We were able to dissect the gracilis completely enveloped in fascia, transecting the muscle as close to its origin and the tendon as distally as possible to provide maximum length. Furthermore, we dissected as long of a pedicle as possible (Figure 5).

Figure 5.

(a) Harvested gracilis muscle with skin paddle and (b) harvested gracilis muscle enveloped in fascia.

The vascular anastomosis was completed first using a Sharpoint 10-0 Nylon 70-µm needle, and the muscle was allowed to perfuse for 10 minutes until the venous outflow did not appear overly dark. The venous anastomosis was then completed as quickly as possible to minimize permanent ischemic changes to the muscle. Irreversible muscle loss increases with time in a nonlinear relationship. Our ischemia time was approximately 40 minutes. If the muscle ischemia time exceeds 2 hours, the muscle will likely survive, but the function will not be compatible with activities of daily living.

The neurorrhaphy was completed next using a 9-0 Nylon 100-µm needle. Two simple stitches were placed at 180° to one another in the epineurium. The neurorrhaphy site was performed as closely as possible to the transplanted muscle. Fibrin glue was used to enhance our repair.

The muscle was then secured to its new origin site using 2-0 Fiberwire suture at the distal clavicle. The new muscle origin was then spread out as much as possible to match the width of the prior origin. The elbow was placed in full extension with the arm at the patient’s side. The muscle was stretched to restore its resting length using our 5-cm marker sutures for reference, and the distal insertion to the radial tuberosity was performed using a Krackow stitch and 2 suture anchors (Figure 6).

Figure 6.

Diagrammatic representation of the gracilis muscle used for reconstruction for elbow flexion (Copyright: Timothy C. Hengst, printed with permission).

Note. Gracilis m. flap = gracilis muscle flap; Thoracoacromial a & v = thoracoacromial artery and vein; medial pectoral n. = medial pectoral nerve.

Doppler was used, which demonstrated excellent flow through the anastomosis and distal portion of the muscle at the location where the pedicle entered the muscle. A Hemovac drain was placed, and wound closure was performed with attention to avoiding compression of the vascular pedicles, as a compartment-like syndrome can occur when the reperfused muscle swells postoperatively. Brisk capillary refill was noted. The patient was placed in a long-arm posterior splint at 90° of elbow flexion with neutral rotation. He began hand therapy at 8 weeks postoperatively, and a muscle stimulator device was used during therapy sessions.

Results

The postoperative course was uneventful. The transferred muscle survived without any postoperative vascular compromise. Preoperatively, the patient had no active elbow flexion and thus had a Medical Research Council (MRC) grade of 0. Postoperatively, the patient gained a muscle function of MRC muscle grade of 4 and achieved 25° to 140° of active elbow range of motion. Furthermore, he maintained full pronation and supination. His passive range of motion was achieved at 2 months postoperatively. At 6 months postoperatively, the patient had palpable contraction of the FFGMT (M1). He was able to actively flex his elbow at 9 months postoperatively (M3). By 1 year postoperatively, he had gained M4 function, which he has maintained. (Figure 7) Our patient is currently in school and finds his result from the FFGMT very useful. It enables him to carry out his activities of daily living. He and his parents are glad of having undergone the operation. If he had the choice, he would choose to undergo the operation again.

Figure 7.

(a-c) Elbow range of motion at 4.5-year follow-up.

Discussion

The ability to create or restore elbow flexion to the upper extremity through free functional muscle transfer can provide a patient with confidence through the competence for self-care through feeding and personal hygiene. In arthrogryposis, available options for muscle transfers may be limited due to weak or absent musculature required for transfer.

In young patients, an FFGMT is a safe operation, and reinnervation of the transferred muscle occurs earlier than it does in adults.¹⁶ Delay in reconstruction until adulthood can result in contracture of the elbow, which will require extensive training for effective use of the upper arm.

Until skeletal maturity, the patient will continue to develop a flexion contracture to the left elbow as the body grows and as FFGMT is unable to achieve further length. Patients must be counseled about this inevitable postoperative finding. To decrease the amount of flexion contracture, our patient will have to continue nightly elbow extension splinting through adulthood. We like to see the patient every 6 months to document this occurrence and encourage compliance with splinting.

In our case, 2 motor branches from the lateral pectoral nerve to the pectoralis major were identified in the field of dissection, which both provided ample length and strong contraction with stimulation. Thus, one was chosen as our donor nerve to the recipient obturator nerve of the FFGMT. In addition, the spinal accessory or intercostal nerve could have been an alternative option. In this case, we believe that the pectoral nerve was the optimal choice due to its shorter distance from the anastomosis and strong contraction with intraoperative nerve stimulation.

Conclusion

A motor branch to the pectoralis major may be used as an adequate donor nerve in a FFGMT to establish elbow flexion as evidenced through our 4.5-year follow-up results in a patient with arthrogryposis.