Gracilis muscle dissection and muscle insertion

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The gracilis muscle or myocutaneous FFMT is the best choice of donor muscle for elbow or hand reconstruction in BPI reconstruction. The requirement for a myocutaneous flap is more common than muscle alone to allow monitoring of the flap's viability. The gracilis muscle is a long strap muscle with a long distal tendon, vascular-ized by a long dominant neurovascular pedicle. A single motor nerve, the anterior branch of the obturator nerve, can be dissected and traced upward to the obturator foramen or retroperitonium to obtain a very long length, 10 cm or more, which is very important for direct nerve coaptation after

Gracilis Myocutaneous Flap

Fig. 7. A 21-year-old patient in a motorcycle accident sustained total root avulsions C4-T1 of his right brachial plexus 10 months before the reconstruction. A left gracilis myocutaneous FFMT for finger extension using the XI nerve as a neurotizer, and a right gracilis myocutaneous FFMT for finger flexion using IC nerves as a neurotizer were performed in two different stages. He achieved finger extension (A), and flexion (B) with the help of a splint to keep the wrist in neutral, the thumb in internal rotation, and the metacarpophalangeal joint in mild flexion.

Fig. 7. A 21-year-old patient in a motorcycle accident sustained total root avulsions C4-T1 of his right brachial plexus 10 months before the reconstruction. A left gracilis myocutaneous FFMT for finger extension using the XI nerve as a neurotizer, and a right gracilis myocutaneous FFMT for finger flexion using IC nerves as a neurotizer were performed in two different stages. He achieved finger extension (A), and flexion (B) with the help of a splint to keep the wrist in neutral, the thumb in internal rotation, and the metacarpophalangeal joint in mild flexion.

the proximal muscle end is fixed. Similarly, the dominant vascular pedicle, entering the muscle on its deep surface 8 to 10 cm distal to the pubic tubercle, can also be dissected proximally to the medial femoral circumflex artery or profunda femoral artery, about 6 cm or more (6 to 8 cm) in length. However, to allow direct nerve coaptation, a vein graft to the artery or vein may occasionally be required to allow end-to-side anastomies to the deep subclavian or axillary artery. For reconstruction of elbow flexion or extension, the whole gracilis muscle with a short length of tendon (1 to 2 cm below the tenomuscular junction) is adequate (Fig. 8A). But, for reconstruction of finger extension or flexion, the whole gracilis muscle and entire tendon down to the gracilis insertion on the anterior surface of the tibia is required (Fig. 8B). Even so, a tendon graft to provide adequate length is often required when the XI nerve is used as a neurotizer or the gracilis FFMT is use for extensor digitorum communis (EDC) reconstruction. An oval-shaped skin paddle is always marked over the proximal muscle for a gracilis myocutaneous FFMT.

XI nerve dissection

The XI nerve is the most commonly used nerve for FFMT neurotization in BPI reconstruction. The XI nerve is located at the midpoint of the lateral margin of the sternocleidomastoid muscle, or one finger breadth above the transverse branch of the external jugular vein, passing laterally and obliquely down to the clavicle-acromion junction. Dissection of the XI nerve can be performed in two ways: (1) from proximal to distal, the XI nerve can be found within one finger breadth above the emergence of the greater auricular nerve; or (2) from distal to proximal, the attachment of the trapezius muscle to the clavicle is detached and the XI nerve can be found in the alveolar tissue anterior to the trapezius muscle. Dissection should continue as far distally as possible below the junction of the cervical sensory branch down to two or three branches entering into the muscle before being divided. The cervical sensory branch can be ligated with 6-0 nylon and used as a traction suture to pull the divided XI nerve superiorly through a skin tunnel, leaving it over the deltoid muscle for nerve coaptation. The main terminal branch is coapt to the motor nerve of the transferred gracilis muscle, the remaining 2 or 3 branches can be elongated with a nerve graft (2 cm in length) and also coaptated to the remaining exposed portion of the motor nerve of the transferred gracilis muscle.

The contralateral gracilis myocutaneous FFMT is selected because the vessels match the site of the recipient vessels. For elbow flexion, the proximal end of the gracilis muscle is fixated at the coracoid process of the scapula. The obturator nerve is laid over the deltoid muscle for nerve coaptation. The anterior thoracic, thoracoacromi-nal, or thoracodorsal vessels with additional cephalic vein can all be used for vessel anastomoses. The distal tendon is passed through a subcutaneous tunnel and sutured to the distal biceps tendon by weaving under tension.

For EDC reconstruction, the gracilis tendon of origin is fixated at the clavicle. The gracilis muscle is passed through a subcutaneous tunnel to an elbow incision where the origins of the brachior-adialis and EDC are elevated to act as a pulley. The gracilis muscle and tendon are passed under the pulley and are sutured to the EDC under tension. The thoracodorsal artery, circumflex humeral artery, and nearby veins are used for

Fig. 8. (A) Whole gracilis myocutaneous FFMT with 1 to 2 cm of tendon is sufficient for arm and forearm muscle replacement. (B) For across the elbow, one muscle for two functions, gracilis myocutaneous FFMT with the entire length of the tendon is harvested through two incisions.

anastomoses. The obturator nerve is easily coap-tated to the XI nerve over the deltoid muscle.

IC nerve dissection

Doi [26] preferred to use the T3-6 IC nerves for the second FFMT procedure: T5-6 IC nerves for a second FFMT for finger flexion, and T3-4 IC nerves to innervate the motor branch of triceps for simultaneous elbow extension. The author prefers to use the three T3-5 IC nerves for FFMT reinnervation either for elbow flexion or for FDP function [28,29]. The IC nerve has a deep central branch and a superficial lateral branch, but only the deep central branch is used for reinnervation. The gracilis myocutaneous FFMT is usually fixed at the coracoid process for elbow flexion, but fixed at the second or third rib for finger flexion. For finger flexion, the muscle passes through a subcutaneous tunnel to the medial elbow incision where the pronator teres and long wrist flexor muscle origins are elevated to form a below-elbow pulley. The muscle is passed under the pulley and is sutured to the FDP by weaving it under tension.

Ph nerve dissection

The Ph nerve can be found over the anterior surface of the anterior scalene muscle and dissected distally down to the sternal notch, and transected. The proximal stump is positioned in the suprascapular fossa and elongated with a nerve graft (about 5 cm or less) to the infraclavicular region for coaptation to the motor nerve of the FFMT.

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