Patient Population

Different types of patients can benefit from FFMT for upper extremity reconstruction and include those with functional loss from the following conditions:

• 
  

  Volkmann ischemic contracture

  
  
• 
  

  Severe brachial plexus preganglionic injury

  
  
• 
  

  Long-standing neurologic injury

  
  
• 
  

  Loss of muscle from trauma

  
  
• 
  

  Loss of muscle from tumor resection

  
  
• 
  

  Electrical injuries to the upper extremity

  
  
• 
  

  Congenital muscle absence

Areas of Reconstruction in the Upper Extremity

• 
  

  Deltoid reconstruction

  
  
• 
  

  Triceps reconstruction

  
  
• 
  

  Elbow flexion

  
  
• 
  

  Finger flexion

  
  
• 
  

  Finger extension

  
  
• 
  

  Thumb opposition

Ideal Candidates

• 
  

  Excellent results in children

  
  
• 
  

  Adult patients ideally under the age of 45

  
  
• 
  

  Compliant and motivated patient

  
  
• 
  

  Healthy, with no comorbidities that would put the patient at risk during the FFMT or that would compromise the ability to complete the extensive rehabilitation required for optimal results

  
  
• 
  

  Access to skilled therapists, knowledgeable in upper extremity and FFMT rehabilitation

Absolute

• 
  

  Medical comorbidities that would not allow a patient to undergo a long surgical procedure safely

  
  
• 
  

  No acceptable donor nerve to innervate the transferred muscle

  
  
• 
  

  Inadequate recipient vessels for microvascular anastamosis

  
  
• 
  

  Patient unable to participate in and complete the time-consuming rehabilitation program for the FFMT

Relative

• 
  

  Poor passive range of motion of the involved joints across which the muscle is to act: The patient may require staged procedures to prepare the upper extremity for the FFMT, such as tenolysis, capsulotomies, and/or contracture release. This requires attentive postoperative physiotherapy before the staged FFMT.

  
  
• 
  

  Lack of antagonistic muscle function: This can be reconstructed with a double transfer3 or a second FFMT, or function can be augmented with additional procedures, such as total wrist arthrodesis.

  
  
• 
  

  Poor soft-tissue coverage: The FFMT can include a skin paddle to address both a soft-tissue loss as well as a functional loss.

  
  
• 
  

  Poor sensation in the hand of the extremity requiring reconstruction: This can be addressed with sensory nerve reconstruction either before or at the same time as the FFMT.

Physical Exam

• 
  

  A detailed preoperative physical exam is important to evaluate which nerves are functioning in the upper extremity, and to identify the options for innervating the FFMT.

  
  
• 
  

  A focused vascular exam of the upper extremity is also important. This involves identifying palpable arteries and those that can be identified by Doppler. It is also important to perform a preoperative Allen test for planning reconstructive procedures in the forearm.

  
  
• 
  

  The soft-tissue coverage for the site of the transfer should be assessed to ensure it is adequate.

  
  
• 
  

  Passive range of motion of the joints across which the muscle is to act should be evaluated, and the excursion of the recipient tendons should be tested.

Investigation

• 
  

  Nerve conduction studies are usually not helpful for preoperative planning.

  
  
• 
  

  Electromyography can be useful to assess muscle function. This can be used in the distal forearm to evaluate the pronator quadratus, which can give useful information about the functional status of the anterior interosseous nerve.2

Imaging

• 
  

  Magnetic resonance imaging (MRI) is useful to assess the viability of the muscles in the upper extremity. The condition of the nerves can also be evaluated with high-powered MRI studies (3 Tesla and above), and this can be helpful in preoperative planning.

  
  
• 
  

  Angiography is a useful way to assess the arterial supply in the upper extremity, especially after traumatic injuries.2 This is key in the preoperative planning for these patients.

Gracilis

• 
  

  The gracilis is a strap muscle, with an average muscle fiber length of 24 cm. The muscle fibers insert sequentially into its tendon. The individual fibers in the average muscle have a length of 16 to 30 cm.

  
  
• 
  

  An adult gracilis muscle shortens 12 to 16 cm when stimulated to maximal contraction; hence, the useful range of powerful muscle excursion is ~ 8 to 10 cm.

  
  
• 
  

  The gracilis is anatomically located in the medial thigh, posterior to the adductor longus muscle and superior to the adductor magnus muscle.

  
  
• 
  

  The sartorius muscle is lateral.

  
  
• 
  

  The semimembranosus and semitendinosus muscles are posterior.

  
  
• 
  

  The origin is the pubic tubercle.

  
  
• 
  

  The insertion is the medial aspect of the tibial tubercle (pes anserinus).

  
  
• 
  

  The gracilis muscle is classified as a type II muscle, with a dominant pedicle and minor pedicles.

  
  
• 
  

  Its dominant blood supply is the ascending branch of the medial femoral circumflex artery, originating from the profunda femoral artery, and entering the superior third of the muscle. The pedicle enters 8–12 cm distal to the origin of the muscle at the pubic tubercle. It is 1–2 mm in diameter and can be dissected to 4–6 cm in length.

  
  
• 
  

  Minor blood supply: 1–2 perforators from the superficial femoral artery entering the distal half of the muscle.

  
  
• 
  

  The dominant pedicle has two venae comitantes, each measuring 1 to 4 mm in diameter. They commonly converge to one main vena comitans at the level of the profunda femoral vein.

  
  
• 
  

  Innervation is from the obturator nerve (anterior division).

  
  
• 
  

  There is a single motor nerve, the anterior branch of the obturator nerve, composed of two or three fascicles. The nerve enters the muscle immediately proximal to the vascular pedicle and lies under the adductor longus. With nerve stimulation, the adult gracilis muscle shortens more than 50% of its extended length, for a functional contraction of 12 to 15 cm.

  
  
• 
  

  By using a nerve stimulator with frequency and voltage control, it is usually possible to separate the muscle into longitudinal, separately functioning neuromuscular territories. Ninety percent of the time, a single fascicle controls the anterior 20% to 50% of the muscle, with the remaining portion controlled by the remaining fascicles. This functional separation is useful when the muscle is used to provide independent thumb and finger flexion.

Latissimus Dorsi

• 
  

  The latissiumus dorsi is anatomically located in the posterior-inferior trunk.

  
  
• 
  

  Superior fibers are deep to the trapezius muscle.

  
  
• 
  

  The majority of the muscle is superior to the posterior trunk musculature (erector spinae, serratus posterior inferior, and serratus anterior).

  
  
• 
  

  The lateral border can have adhesions with the serratus anterior muscle, and it is important to recognize and divide these during flap harvest.

  
  
• 
  

  The origin is the T6–T12 vertebrae, lower four ribs, posterior iliac crest, and minor attachments to the scapula.

  
  
• 
  

  The insertion is the medial border of the intertubercular groove of the humerus.

  
  
• 
  

  The latissimus dorsi muscle is classified as a type V muscle, as it has one dominant artery and multiple segmental perforators.

  
  
• 
  

  Its dominant blood supply is the thoracodorsal artery, originating from the subscapular artery. It is 1.5–3.0 mm in diameter and enters the muscle ~ 10–15 cm inferior to the muscle insertion on the humerus.

  
  
• 
  

  Its minor blood supply consists of posterior lumbar perforating vessels, medially, and posterior intercostal perforating vessels, laterally.

  
  
• 
  

  The dominant artery is accompanied by two venae comitantes, which usually join to form a single vein as they approach the subscapular vein. The single vena comitans usually varies in size from 3 to 5 mm.

  
  
• 
  

  Innervation is from the thoracodorsal nerve.

  
  
• 
  

  The nerve travels with the vascular pedicle.

  
  
• 
  

  Like the obturator nerve supplying the gracilis, the thoracodorsal nerve divides into two motor territories that can be isolated for independent functional reconstruction. One division supplies the lateral portion of the muscle, and the other supplies the medial portion, allowing two functionally separate neuromuscular territories in 80% of muscles.

Patient Positioning

• 
  

  For free functional gracilis muscle transfers, patients are most commonly placed supine. This allows access to the upper extremity for reconstruction as well as to the leg for gracilis muscle harvest.

  
  
• 
  

  The gracilis muscle is harvested with the patient in a frog-leg position.

  
  
• 
  

  The preference is to use the contralateral gracilis for elbow flexion and finger extension reconstruction, and the ipsilateral gracilis for finger flexion reconstruction. This orientation is chosen based on the position of the recipient vessels.

  
  
• 
  

  Free functional latissimus dorsi muscle transfer requires planning for patient positioning.

  
  
• 
  

  The latissimus dorsi muscle can be harvested with the patient either prone or in the lateral decubitus position.

  
  
• 
  

  Muscle transfer and origin and insertion creation require repositioning the patient into the supine position.

  
  
• 
  

  Occasionally, for finger flexion or extension reconstruction, the entire procedure can be performed in the lateral decubitus position.

  
  
• 
  

  A tourniquet is used on the upper extremity during the preparation of the forearm for functional finger flexion or extension reconstruction.

  
  
• 
  

  It is important to ensure the tourniquet is deflated, or completely removed from the extremity, before performing the microvascular anastomosis to ensure it does not affect the arterial inflow to the muscle.