Title: Free Medial Sural Artery Perforator Flap for Resurfacing Distal Limb
Defects
Authors: Shao L. Chen, MD, Tim M. Chen, MD, Hsian J. Wang, MD
The need for thin flap coverage has increased, especially for contouring or
covering shallow defects of distal limb. The free medial sural artery perforator
flap harvested from the medial aspect of the upper calf can be useful for this
purpose. The medial sural artery supplies the medial gastrocnemius muscle and
sends perforating branches to the overlying skin. Its perforator flap is based
upon the proximal major perforator of the medial sural artery.
Patients: Between January of 2002 and February of 2003, the free medial sural
artery perforator flap was used for the reconstruction of shallow defects over
the distal limbs of 11 individuals. The patients included nine men and two women,
ranging in age from 21 to 60 years. Four recipient sites were located on the hands,
and seven on the feet. The existing soft tissue defects among all patients resulted
from trauma, painful scar, and chronic ulcer and grafting was contraindicated
due to the exposure of tendons and/or bones at the wound site.
Methods: After general anesthesia is administered, the patient can be placed in
a supine or prone position, corresponding to the location of the defect, and the
ipsilateral leg is usually selected for the donor tissue. Initially, the axis
of the medial sural artery is defined with the assistance of Doppler ultrasound.
Following this, the point of emergence of the proximal major perforator can be
identified along the axis of the medial sural artery. The flap is designed on
the basis of the proximal major perforator, which is placed on the proximal third
of the flap to increase effective pedicle length, and the size of the flap is
determined by the defect to be repaired.
With the aid of tourniquet control and loupe magnification, the anterior border
of the flap is incised first through the skin, subcutaneous tissue, and deep fascia
to the underlying muscle. From this stage, the flap can be quite easily detached
from the underlying muscle, due to the loose areolar tissue that lies between
the deep fascia and the muscle, and the detaching continues until the selected
perforator is encountered. The next step involves the intramuscular retrograde
dissection of the perforator. Leaving several strips of muscle fiber attached
to the pedicle allows safe dissection. Once adequate pedicle length and suitable
caliber of the medial sural artery have been achieved, the posterior margin of
the flap is incised and the flap is further detached from the muscle.
Results: Surgical anatomy- From our anatomical findings, most of the proximal
major perforators of the medial sural artery emerged in an area between 6 and
9 cm from the popliteal crease and around 5 cm from the posterior midline of the
leg, correlating with the axis of the medial sural artery. As the flap was raised,
we could see the perforator, ranging from 0.8 to 2.0 mm in external diameter,
sprouting from the medial gastrocnemius muscle to the overlying deep fascia.
Clinical series- The size of the flap ranged from 4 x 3.5 cm to 13.5 x 6.5
cm. The donor defects were resurfaced with split-thickness skin grafts for eight
patients and were closed primarily for the remaining three patients. All flaps
were safely raised with a single perforator, except for the largest one which
included two perforators from the same branch of the medial sural artery.
Conclusion: The main advantage of the medial sural artery perforator flap is that
it only requires cutaneous tissue to achieve better accuracy in reconstructive
site, and it preserves the medial gastrocnemius muscle and motor nerve to minimize
donor-site morbidity. The authors conclude that the free medial sural artery
perforator flap has greater potential for resurfacing moderate defects of distal
limbs, because of its reliability, thinness, and easy elevation.
References:
1. Cavadas, P.C. et al. The medial sural artery perforator free flap. Plast.
Reconst. Surg. 108:1609, 2001.
2. Hallock, G.G. Anatomic basis of the gastrocnemius perforator-based flap. Ann.
Plast. Surg. 47:517, 2001.