A porcine model for multiple musculocutaneous flaps.

The purpose of this study was to develop and describe in detail a reproducible porcine model for musculocutaneous flap study. The model was required to demonstrate the following: 1. consistent, easily identifiable anatomical landmarks for muscles and muscular vascular pedicles; 2. flap survival, consistent with the musculocutaneous perforator arrangement of blood supply; 3. ease of islanded- or free-flap formation; 4. arrangement of flaps on each animal, allowing paired studies of control and experimental flaps; and 5. a maximum number of flaps per animal, without undue morbidity or mortality. Pilot dissections were made of the pectoralis, trapezius, latissimus dorsi, gracilis, biceps femoris, and tensor fasciae latae muscles and their major vascular pedicles. After establishing the anatomical landmarks, we formed musculocutaneous flaps at each site to verify the above five requirements. A total of 72 muscle/vessel pedicle dissections were performed, incorporating formation of 61 island musculocutaneous flaps. The skin component overlying an islanded muscle block survived in 60 instances, confirming the reliability of the flap model. We concluded that five pairs of musculocutaneous flaps could be fashioned on one pig, using the bilateral control/experimental paradigm if desired. The pectoralis, latissimus dorsi, trapezius, gracilis, and biceps femoris muscles were used. The ventral muscle group (pectoralis, gracilis) was raised in one operating session, and the lateral muscles (trapezius, latissimus dorsi, biceps femoris) were raised in one further session per side. Three new porcine flaps are described--the pectoralis, biceps femoris, and trapezius. Morbidity was confined to mild splinting of the limbs for one day. This is also the first example of the use of ten musculocutaneous island flaps on one pig, and represents an opportunity for performing physiological, pathological, or pharmacological experiments on the musculocutaneous flap.