Functioning Free Muscle Transplantation Research Articles

Traumatic major muscle loss in the upper extremity: reconstruction using functioning free muscle transplantation.

Traumatic crushing injuries of the muscle compartments will occasionally cause major muscle or muscle-group loss with concomitant irreparable nerve injuries. Those cases with or without the availability of local muscle transfers form another indication for functioning free muscle transplantation (FFMT). The authors report their experience with 20 FFMTs in 14 patients with severe muscle loss from 1986 to 1996. They were selected because all their major muscle loss was primarily due to muscle avulsion, avascularity, and necrosis, but not secondarily due to nerve injury or ischemic injury. The motor nerves innervating these muscles were either disrupted after muscle debridement or avulsed from the neuromuscular junction concomitantly. The initial injury in this series was so severe that in many cases amputation was advised. Fractures were present in almost half the cases (6/14). Half the cases required revascularization due to rupture of major vessels (7/14), and the need for free-tissue transfer for soft-tissue coverage was demonstrated in over two-thirds (8/14). All FFMTs were innervated by the motor nerve which originally innervated the lost major muscle(s), and to replace palmar arm compartment (elbow flexors, 6 cases), palmar forearm compartment (finger flexors, 6 cases), and dorsal forearm compartment (finger extensors, 8 cases). Postoperative follow-up ranged from 3 to 12.5 years (average: 8.3 years). The success rate, i.e., achieving M4 muscle strength, was nearly 90 percent (18 of 20 FFMTs). Two cases with sub-optimal results were performed in the acute stage for the purpose of soft-tissue coverage and functional results. These reconstructions make the originally compromised limb useful for most activities of daily living. This type of injury should be recognized as providing a good prognosis after application of the FFMT, and arbitrary amputation should be avoided.

FUNCTIONING FREE-MUSCLE TRANSPLANTATION FOR THE UPPER EXTREMITY

Functioning free-muscle transplantation (FFMT) is an advanced microneurovascular technique indicated in patients who have an injury with major functional muscle or muscle group loss or denervation and no locally available or ideal musculotendinous donor units. Over the 9-year period, from 1986 to 1994, 47 FFMTs were applied in patients who had severe hand and upper-extremity injuries (not including brachial plexus injury). Thirteen patients had 15 FFMTs to reconstruct muscle loss caused by severe Volkmann's ischemia. Seventeen patients had 21 FFMTs for reconstruction after severe crushing and traction injuries of the forearm or arm, with major muscle loss or major nerve injury. Nine patients, with 11 FFMTs, sustained major limb avulsion amputation for which replantation without nerve repair was done initially. FFMT was the only technique available to resolve the motor deficit and consequent deformity. Most patients achieved significant functional improvement.

Scutuloauricularis muscle of the rabbit: a new model for free functional muscle transplantation in the mimic system.

There is little information on the specific process of free, functional muscle transplantation to the face trying to restore mimic function. Up to now one of the main reasons was the impossibility of functional assessment of mimic muscles as well as their transplanted substitutes. The scutuloauricularis muscle provides an ideal model for quantitative assessment of muscle function because of its circumscript tendinous insertion and is suitable for microsurgical transplantation. In a series of 26 adult, female New Zealand rabbits the anatomical and microsurgical details were studied. The scutuloauricularis muscle weighs 1.018 +/- 0.106 g, it is supplied by the auricularis rostralis artery (diameter 0.4 +/- 0.1 mm) and the auricularis rostralis vein (diameter 1.3 +/- 0.1 mm) and one oligofascicular (2-3 fascicles) branch of the facial nerve. During isometric contraction under supramaximal electrostimulation the maximal tetanic tension was 2.995 +/- 0.928 N. Histomorphometric studies in ATP-ase stained cross-sections showed 40.5 +/- 4.6% type I fibres, 32.3 +/- 5.2% type IIA fibres, and 27.2 +/- 7.1% type IIB fibres.

Scutuloauricularis muscle of the rabbit: A new model for free functional muscle transplantation in the mimic system

Scutuloauricularis muscle of the rabbit: A new model for free functional muscle transplantation in the mimic system

Irreversible muscle contracture after functioning free muscle transplantation using the ipsilateral facial nerve for reinnervation

Four patients who underwent functioning free muscle transplantation (FFMT) for facial reconstruction developed a progressive disfiguring muscle contracture. This complication has not been previously reported. Three of the patients had longstanding facial paralysis and were reanimated by FFMT. The fourth patient had left hemifacial atrophy but without facial paralysis. She also underwent FFMT for augmentation. All four FFMTs were innervated by the ipsilateral facial nerve. Initially, they all had a normal facial appearance at rest during the first few months after FFMT. However, they all developed a progressive severe muscle contracture from 6 to 12 months after FFMT. Continuous spontaneous electrical impulse activity, which stimulated the transferred muscle day and night, may be responsible for the progressive muscle contracture. From the patients' reported sensations and from clinical evaluation, which included a local xylocaine injection test, over-reinnervation with a synkinesis effect of the transferred muscle is hypothetically the main cause, not over-tension of the muscle itself. This complication may possibly be avoided by limiting or decreasing the number of fascicles from the ipsilateral facial nerve or better by using a cross-facial nerve graft instead of the ipsilateral facial nerve as the innervating motor nerve. The outcome with a cross-facial nerve is likely to be more predictable and reliable.