Extension of the Musculocutaneous Flap by Surgical Delay

Abstract

The musculocutaneous flap has lim¬ its on survival of its skin segment. Ran¬ dom skin extensions beyond muscle mar¬ gins have, by clinical experience, been shown to survive. It has not been proved, however, what quantity of random skin will survive or whether its viable dimen¬ sions can be augmented by surgical delay. Twenty-five porcine musculocuta¬ neous island flaps were created with a random skin extension running beyond the likely limit of survival. Twenty-five paired contralateral flaps subjected to a surgical delay one week earlier were raised simultaneously. The surviving dimensions of random skin on both con¬ trol and experimental flaps were mea¬ sured 14 days after delay. The control flaps sustained random skin segments one to 48 times their area of muscle while the delay doubled this, engendering more predictable survival. A new, successful experimental technique of increasing skin survival in musculocutaneous flaps is doc¬ umented.With the advent of musculocuta¬ neous flaps as the workhorse of major reconstruction in the face, head, and neck, there comes a concom¬ itant need for knowing the "end points" in their design and survival. In current surgical practice, limits are imposed on the area and length of such flaps by anatomical factors (eg, length and caliber of the muscle's vascular pedicle) and by factors inher¬ ent in the musculocutaneous bloodflow concept. Regarding the latter, the skin component's survival in island flaps is determined entirely by the presence of viable muscle beneath.These limits plus the unique require¬ ments of tissue replacement in the head and neck (robust viability, plas¬ ticity, dynamic function, and good cosmesis) define the specifications of the ideal flap. It should have an extensive, thin, pliable skin segment, a small or moderate-sized muscle block, and a lengthy vascular pedicle. The problem that emerges, then, is how to enable a relatively large skin component to survive with minimal muscle beneath.It has been suggested1·2 that the mus¬ cle component of a musculocutaneous flap is not amenable to delay proce¬ dures. Its survival may be "all or none" when surgical intervention reduces its blood supply. By contrast, pure skin flaps, both random and axi¬ al, will respond to delay in a predictBiceps Femoris Lateral Pectoralis Ascendens (Major) Gracilis Ventral Fig 1.-Porcine model accommodating five musculocutaneous flaps per side on each animal. Top, lateral view; bottom, ventral view.able, measurable fashion.3·4 Perhaps the skin that survives as a random flap beyond the muscle of a musculo¬ cutaneous flap5·6 will also be aug¬ mented by a delay.Because of similarity in the muscu¬ locutaneous vascular anatomy be¬ tween the pig and man7 and the ability Downloaded From: http://archotol.jamanetwork.com/ by a Oakland University User on 05/30/2015

Vascular Delay Revisited

“…A combination of all three resulted in the greatest flap survival in their model and division of vein alone had the least benefit. Numerous authors have reported similar findings using various techniques, corroborating these findings of vasodilation in the first 2 to 3 days after flap elevation [11][12][13][14][15][16][17][18][19][20] (Table 1).…”

“…Summary of Experimental Studies on the Delay PhenomenonHaughey and Panje, 1985 14 1985 Arch. Otolaryngol.…”

Effects of Vascular Endothelial Growth Factor on Survival of Surgical Flaps: A Review of Experimental Studies

“…However, until recently, the surgical delay procedure was the only proven technique to improve tissue survival at and beyond standard flap territory margins. [7][8][9][10][11] Extensive research has been performed on enhancing skin flap viability by pharmacological manipulation. This research includes the use of sympatholytic agents, vasodilators, calcium channel blockers, hemorheological drugs, antithrombotic agents, free radical scavengers, and nootropics.…”

Two-dimensional electrospun nanofibrous membranes for promoting random skin flap survival

“…Up to now, the surgical delay procedure has been used as the only proven technique to improve skin ap survival. 5,6 Recently, methods to reduce skin ap necrosis by early intervention have become a popular research topic.…”