FOREHEAD FLAP

DR DIPTI PATIL (1ST MDS)DEPT OF ORAL

MAXILLOFACIAL SURGERYKCDS,BANGLORE.

CONTENT Introduction History Anatomy Indications Technique Complications Advantages Disadvantages

Introduction

Flap Defined as movement of adjacent skin &

subcutaneous tissue from one location to other with direct vascular supply

Local flaps -random flap -axial pattern Distant flaps Myocutaneous flap Osteomyocutaneous flap Free flap.

Axial pattern Based on the named arteriovenus pedicle that run

within the skin superficial to underlying muscle layer parallel to overlying skin.

Extremely good blood supply so can be raised greater length than the random flaps.

Eg forehead flap, deltopectorial flap

Random pattern Gets vascular supply from cutaneous artery which

runs deep to underlying muscle ie direct cutaneous artery

Height of random pattern flap should not extend 1.5 times length of the base.

Blood supply of flap apex is inversely proportional to its height

Eg rhomboid flap, rotational flap, transpositional flap.

History

Forehead flap Also called as temporal flap.

800 BC - Sushruta, described a nasal reconstruction approach based on pedicled forehead skin flap.

Later describe by McGregor, in 1963.

Its axial pattern myocutaneous flap provide large area of skin & subcutaneous tissue.

Called as lifeboat may be raised quickly to get surgeon out of trouble…

Anatomy

SCALP

Extends from top of forehead in front

to the superior nuchal line behind.

Laterally it projects down to the zygomatic arch and external acoustic meatus.

It consists of five layers: (S) skin, (C) subcutaneous tissue (superficial fascia), (A) occipitofrontalis (epicranius) and its aponeurosis, (L) subaponeurotic areolar tissue and (P) pericranium

Clinical note

Aponeurotic layer is movable along the upper three layers of the scalp,& can easily slide on deepest layer is the periosteum of the skull.

It is very easy to raise a scalp flap within the plane between the galea and the pericranium without compromising the blood or nerve supply of the scalp, because all of these structures lie in the superficial fascia.

SUPERFICIAL TEMPORAL ARTERY its smaller terminal branch of the

external carotid artery.

It arises in the parotid gland behind the neck of the mandible, where it is crossed by temporal and zygomatic branches of the facial nerve.

Initially deep, it becomes superficial as it passes over the posterior root of the zygomatic process of the temporal bone, where its pulse can be felt.

It then runs up the scalp for c.4 cm and divides into frontal (anterior) and parietal (posterior) branches.

It is accompanied by corresponding veins, & auriculotemporal nerve lies posterior to it.

The superficial temporal artery supplies – -skin and muscles at the side of the face -the scalp, -parotid gland and - the temporomandibular joint.

Its branches are

the transverse facial, auricular, zygomatico-orbital, middle temporal, frontal and parietal arteries.

POSTERIOR AURICULAR ARTERY

The posterior auricular artery is small branch arises in the neck from the external carotid artery posteriorly just above digastric and stylohyoid muscle.

ascends between the auricle and mastoid process and gives off an auricular branch supplying the cranial surface of the auricle and an occipital branch to supply the occipital belly of occipitofrontalis and the scalp behind and above the auricle

Supratrochlear artery emerges from the orbit onto the face at the frontal notch. It

supplies the medial parts of the upper eyelid, forehead and scalp.

The supratrochlear artery anastomoses with the supraorbital artery and with its contralateral fellow.

Supraorbital artery leaves the orbit through the supraorbital notch (or foramen). divides into superficial and deep branches, supplying skin

and muscle of the upper eyelid, forehead and scalp. It anastomoses with the supratrochlear artery, frontal branch

of the superficial temporal and its contralateral fellow.

Based on the mangold et al (1980) study on vascular anatomy of the forehead .he divided forehead in vascular territories-

Dorsal nasal arterySupratrochlear arterySupraorbital arterySuperficial temporal artery.

Based on the site– Median forehead flap based on primarily on

Supratrochlear artery, supplemented by dorsal nasal artery.

Paramedian forehead flap based on primarily on Supratrochlear artery, supplemented by supraorbital artery.

Laterally based forehead flap based on primarily on Superficial temporal artery , supplemented by posterior auricular artery.

Indications

Indication

Used for a large number of reconstruction procedures: nose, upper eyelid, cheek (inside and outside), floor of the mouth, chin covering for reconstructed mandible, portion of tongue, and alveolar region.

Technique

Laterally based forehead flap

The forehead flap is outlined.

contour follows the eyebrows (must not extend beyond the level of the lateral canthus to avoid injury to the facial nerve) to anterior border of pinna at level of zygomatic arch and along forehead hairline more pleasing cosmetically.

The incisions are beveled to minimize the cosmetic deformity along the remaining edges of the forehead and scalp

for longer flap most often extends to hair-line of opposite temple.

As it is used for intraoral reconstruction a tunnel is constructed through which flap is passed so that distal end reaches the intra-oral defect.

Based on the route in the mouth- Directly through the cheek(cheek portal) Deep to the zygomatic arch Posterior part of submandibular incision of neck

dissection.

Through the cheek

Tunnel is made outside the cheek avoiding facial nerve damage.

Skin incised horizontally in front of ear appro 1.5 below zygomatic arch(length of incision 2/3 of the flap.

Incision deepened to the parotid level using scalpel then tissue scissor thrust through the substance of cheek in the defect.

Ramus is dissected tunnel is made directly through the mouth with min resistance of parotid.

When ramus is intact tunnel has to bring round in front of bone .

Difficult if defect is extended both forward & backward.

Needs to raise longer flaps Drawback- salivary fistula.

Deep zygomatic arch

By Davis & Hoopes, 1971 Flap is passed downward deep to the arch in to mouth

following the pathway of the temporalis muscle.

Submandibular incision

By Millard ,1964. While his study on primary

bone grafting after mandibular resection, he used forehead flap to provide a lining to cover the bone graft through the submandibular incision of neck dissection.

Flap enter the mouth medial to the mandible extending far back till tongue.

Drawback – inferior fistula

Secondary defect

Secondary defect is covered by split skin graft. Second surgery is done 3 week later & bridge

segment of the flap is returned to the temple or forehead.

Second surgery

Done after 3 weeks, flap is tunneled ,& divided it from outside as far down the tunnel.

Skin closure is done from outside n tunnel is kept patent inside to drain freely.

Rotation forehead

flap

Median forehead

flap

Complication

Infection Cosmetically detrimental Facial nerve injury Need donor area grafting (STG is placed at donor

area). Patient need to expose for second surgery. Flap necrosis (in rare conditions).

Advantage

Rich in vascular supply , so rare chances of flap necrosis.

Long flaps are possible to raise ,can reach to most of oromaxillary defect.

No major vital structure approximating the flap. Lifeboat flap can be easily raised, not a technique

sensitive.

Disadvantage

Donor site defects especially in the younger patient are detrimental.

Compromise of blood supply is possible via the superficial temporal artery if a simultaneous radical neck dissection has sacrificed the external carotid artery. Most important to include the posterior auricular artery with a portion of the scalp above and behind the ear. Delay is advised.

There is danger of compromise of blood supply if the flap is tunnelled deep to the zygomatic arch. If this is the approach to reach the oral cavity, it is best to fracture the arch outward with two osteotomies.

Injury to the facial nerve may occur when performing an access to the oral cavity.

Second surgery is required.

References

Grey’s anatomy Atlas of head & neck surgery- Lore & Madina. Cancer of face & mouth- Lan Mcgregor Heads & surgery – Stell & Maran Local flaps in facial reconstruction- Baker & Swanson

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