Scalp reconstruction
Encyclopedia
Scalp reconstruction is a surgical procedure for people with scalp defects. Scalp defects may be partial or full thickness and can be congenital or acquired. Because not all layers of the scalp are elastic and the scalp has a convex shape, the use of primary closure is limited. Sometimes the easiest way of closing the wound may not be the ideal or best way. The choice for a reconstruction depends on multiple factors, such as the defect itself, the patient characteristics and surgeon preference.

History

Skull and brain 'surgery' are known from the prehistoric era. There is even evidence that scalp reconstructions dates back to the Egyptians in 3000 B.C. and it was also known by the Roman Empire. The word plastic surgery
Plastic surgery
Plastic surgery is a medical specialty concerned with the correction or restoration of form and function. Though cosmetic or aesthetic surgery is the best-known kind of plastic surgery, most plastic surgery is not cosmetic: plastic surgery includes many types of reconstructive surgery, hand...

 probably comes from the Greek word “Plastikos” what means “shape” or “reconstruct”. Damaged skulls have been tried to reconstruct, even though knowledge about neurology, the brain and anatomy were minimal. In musea skulls can be found which show manipulation that can be interpreted as a primitive form of surgery. In Medieval times, people were convinced that trepanation
Trepanation
Trepanning, also known as trephination, trephining or making a burr hole, is a surgical intervention in which a hole is drilled or scraped into the human skull, exposing the dura mater in order to treat health problems related to intracranial diseases. It may also refer to any "burr" hole created...

 was a remedy for various diseases.

Indications

Main reasons for scalp reconstruction are divided into two groups: congenital or acquired. Congenital defects may include aplasia cutis congenita, congenital nevus, congenital vascular malformations and congenital tumors. Acquired defects can be caused by burns, blunt, penetrating, or avulsion injuries, tumor invasion, infection, oncologic resection, radiation, or wound-healing difficulties. Alopecia
Alopecia
Alopecia means loss of hair from the head or body. Alopecia can mean baldness, a term generally reserved for pattern alopecia or androgenic alopecia. Compulsive pulling of hair can also produce hair loss. Hairstyling routines such as tight ponytails or braids may induce Traction alopecia. Both...

 can be an aesthetic motivation for hair bearing scalp reconstruction. As the incidence of basal-cell carcinoma and squamous-cell carcinoma is rising and about 80% are located in the head and neck area, the number of scalp reconstructions will likely increase in the future. Depending on the size and nature of the defect, an appropriate reconstructive method has to be used. By using Mohs surgery
Mohs surgery
Mohs surgery, also known as chemosurgery, created by a general surgeon, Dr. Frederic E. Mohs, is microscopically controlled surgery used to treat common types of skin cancer. It is one of the many methods of obtaining complete margin control during removal of a skin cancer using frozen section...

 the defect can be kept minimal, but nevertheless infiltrative basal cell carcinoma
Infiltrative basal cell carcinoma
Infiltrative basal-cell carcinoma is a cutaneous condition which is an aggressive type of basal-cell carcinoma characterized by deep infiltration....

 may have the need to remove a large part of the scalp.

On the flowchart a simplified algorithm for scalp reconstruction is depicted. The options range from simple solutions for small skin defects to complicated reconstructions requiring multi-tissue reconstructions.

In case of an active and severe infection
Infection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...

, it has to be controlled first by surgical debridement and antibiotic treatment before reconstruction is performed, as infection can cause bacteraemia and has a negative effect on wound healing.

Surgical anatomy

The five layers of the scalp, from superficial to deep, can be easily memorized by using the mnemonic SCALP. The Skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...

 of the scalp is the thickest of the human body, measuring up to 8 mm in thickness and contains approximately 100.000 hair
Hair
Hair is a filamentous biomaterial, that grows from follicles found in the dermis. Found exclusively in mammals, hair is one of the defining characteristics of the mammalian class....

s. Hair lines make scalp reconstruction difficult because the hair lines have to be respected to get a satisfying aesthetic result.
The subCutis is a layer of fat, enclosed in compartments formed by rigid fibrous septa. Their inelasticy prevents bleeding vessels to collapse and retract under the skin to achieve haemostasis. All large blood vessels and nerves of the scalp are located in this layer.
The next layer is the galea Aponeurotica
Galea aponeurotica
The galea aponeurotica is a tough layer of dense fibrous tissue which covers the upper part of the cranium; behind, it is attached, in the interval between its union with the Occipitales, to the external occipital protuberance and highest nuchal lines of the occipital bone; in front, it forms a...

, which separates the underlying bone and the overlying layers. The large blood vessels and nerves of the scalp don’t pierce this layer.
Loose connective tissue between the periostium and the aponeurosis makes these two rigid structures easily slide over each other and contributes to skin movement. Thus, if vascular and nervous anatomy is respected, the skin, sucutaneous tissue and galea aponeurotica can be lifted off the skull with minimal bleeding, nerve damage, or chance of necrosis. This method was first described by Orticochea in 1967, but has been updated to minimize scarring.
The fifth layer is the Periosteum
Periosteum
Periosteum is a membrane that lines the outer surface of all bones, except at the joints of long bones. Endosteum lines the inner surface of all bones....

 of the skull, also referred to as pericranium. It can be separated from the skull, except near the sutures. The skull consists of an inner and outer table, with spongy bone in between known as diploë
Diploë
Diploë refers to the spongy bone structure of the internal part of short, irregular, and flat bones.In the cranial bones, the layers of compact tissue are familiarly known as the tables of the skull; the outer one is thick and tough; the inner is thin, dense, and brittle, and hence is termed the...

.

Vascular supply

On both sides of the scalp there are five large arteries which perfuse the scalp. Local flaps used for scalp reconstruction must contain at least one of these major arteries, to maintain a reliable blood supply. The scalp can be divided into four different vascular territories:
  • Anterior: supratrochlear artery
    Supratrochlear artery
    The supratrochlear artery , one of the terminal branches of the ophthalmic artery, branches off where the ophthalmic travels posterior to the trochlea.-Course:...

     and supraorbital artery
  • Lateral: superficial temporal artery
    Superficial temporal artery
    In human anatomy, the superficial temporal artery is a major artery of the head. It arises from the external carotid artery when it bifurcates into the superficial temporal artery and maxillary artery....

  • Posterior: occipital artery
    Occipital artery
    The occipital artery arises from the external carotid artery opposite the facial artery, its path is below the posterior belly of digastric to the occipital region. This artery supplies blood to the back of the scalp and sterno-mastoid muscles...

  • Posterolateral: posterior auricular artery
    Posterior auricular artery
    The posterior auricular artery is a small artery and arises from the external carotid artery, above the Digastric muscle and Stylohyoid muscle, opposite the apex of the styloid process....



The veins anastomose frequently with each other and enter the diploic veins of the skull bones and the dural sinuses. This is an extra difficulty as the vein pattern differs. The scalp veins accompany the arteries and have similar names:
  • Anterior: Supratrochlear vein and supraorbital vein
    Supraorbital vein
    The supraorbital vein begins on the forehead where it communicates with the frontal branch of the superficial temporal vein.It runs downward superficial to the Frontalis muscle, and joins the frontal vein at the medial angle of the orbit to form the angular vein.Previous to its junction with the...

  • Lateral: Superficial temporal vein
    Superficial temporal vein
    -Path:It begins on the side and vertex of the skull in a plexus which communicates with the frontal vein and supraorbital vein, with the corresponding vein of the opposite side, and with the posterior auricular vein and occipital vein....

  • Posterior: Occipital vein
    Occipital vein
    The occipital vein begins as a plexus at the posterior aspect of the scalp from the external occipital protuberance and superior nuchal line to the back part of the vertex of the skull....

  • Posterolateral: Posterior auricular vein
    Posterior auricular vein
    The posterior auricular vein begins upon the side of the head, in a plexus which communicates with the tributaries of the occipital vein and superficial temporal veins....


Lymphatic system

The frontal part of the scalp is drained to the parotid, submandibular, and deep cervical lymph nodes. The posterior part is drained to the posterior auricular and occipital lymph nodes. Malignancies of the scalp can metastasize to these lymph nodes. Brain tumors, however, tend to metastasize haematogenously.

Innervation

The scalp is innervated by motor nerves and sensory nerves. The trigeminal nerve
Trigeminal nerve
The trigeminal nerve contains both sensory and motor fibres. It is responsible for sensation in the face and certain motor functions such as biting, chewing, and swallowing. Sensory information from the face and body is processed by parallel pathways in the central nervous system...

 (CNV) is one of the important cranial sensory nerves which innervates the scalp. From anterior to posterior front to back the nerves are:
  • Supratrochlear nerve
    Supratrochlear nerve
    The supratrochlear nerve is a branch of the frontal nerve, which itself comes from the ophthalmic division of the trigeminal cranial nerve.It is smaller than the nearby supraorbital nerve...

     and Supraorbital nerve
    Supraorbital nerve
    The supraorbital nerve is a terminal branch of the frontal nerve.It passes through the supraorbital foramen, and gives off, in this situation, palpebral filaments to the upper eyelid...

  • Zygomaticotemporal nerve
    Zygomaticotemporal nerve
    The zygomaticotemporal nerve or zygomaticotemporal branch is derived from the maxillary branch of the trigeminal nerve...

  • Auriculotemporal nerve
    Auriculotemporal nerve
    The auriculotemporal nerve is a branch of the mandibular nerve that runs with the superficial temporal artery and vein, and provides sensory innervation to various regions on the side of the head.-Origin:...

  • Lesser occipital nerve
    Lesser occipital nerve
    The lesser occipital nerve or small occipital nerve is a cutaneous spinal nerve arising between the second and third cervical vertebrae, along with the greater occipital nerve...

  • Greater occipital nerve
    Greater occipital nerve
    The greater occipital nerve is a spinal nerve, specifically the medial branch of the dorsal primary ramus of cervical spinal nerve 2. This nerve arises from between the first and second cervical vertebrae, along with the lesser occipital nerve. It ascends after emerging from the suboccipital...


Dura mater reconstruction

Dural lesions should be closed to aviod CSF
CSF
-Biology and Medicine:* Cerebrospinal fluid* Colony-Stimulating Factor* Cancer slope factor* Classical swine fever* Certain safety factor-Military:* Central Security Forces , an Egyptian paramilitary force...

 leakage. Also, a defect acts like a porte d'entree for micro-organisms that can cause meningitis
Meningitis
Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...

. If fibrin glue or primary closure is not possible, patches have to be used. These are made from cadaveric dura mater, xenografts (tachosil
TachoSil
TachoSil is a collagen sponge coated with the human coagulation factors fibrinogen and thrombin. It is used during surgery to stop local bleeding on internal organs . The sponge is manufactured from horse tendons. TachoSil reacts upon contact with blood, other body fluids or saline to form a clot...

, duragen, durepair), or synthetic grafts materials (PTFE, neuropatch). However, (vascularised) autografts (fascia lata, muscle or omentum majus) are preferred in irradiated or severely infected defects.

Bone defects

Skull defects should be closed in order to protect the brain. The occipital and temporal regions bear the most pressure while sleeping and therefore need to be reconstructed. Frontal bone defects cause a contour defect, therefore, aesthetic considerations are often taken into account to reconstruct this area. Midsagittal defects are of lower importance, as they allow only penetrating trauma. When the reconstruction cannot be performed immediately, wearing a helmet is advised.
Skull deformities can result in high intracranial pressure
Intracranial pressure
Intracranial pressure is the pressure inside the skull and thus in the brain tissue and cerebrospinal fluid . The body has various mechanisms by which it keeps the ICP stable, with CSF pressures varying by about 1 mmHg in normal adults through shifts in production and absorption of CSF...

 which can cause complaints ranging from headaches to epilepsy-like seizures.
Small defects can be filled with morcellized bone, which will consolidate in some weeks. Because of the anatomy of the skull, the external table can be split off the internal table and then be moved over the defect. Rib grafts (whether or not accompanied with the latissimus dorsi muscle
Latissimus dorsi muscle
The latissimus dorsi , meaning 'broadest muscle of the back' , is the larger, flat, dorso-lateral muscle on the trunk, posterior to the arm, and partly covered by the trapezius on its median dorsal region.The latissimus dorsi is responsible for extension,...

) are suitable for larger defects and can bear pressure, but do not cover the whole defect. Implants can be used as well, but are not preferred in patients who are to be irradiated or recently have had an infection or necrosis, because of the increased risk of infection and extrusion.
These implants can be factory-made out of metal (titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....

), synthetic materials (PMMA
PMMA
PMMA can refer to* Para-Methoxymethamphetamine, a stimulant drug* Philippine Merchant Marine Academy* Poly, a transparent thermoplastic often used as a glass substitute...

, PEEK
PEEK
Polyether ether ketone is a colourless organic polymer thermoplastic used in engineering applications.-Synthesis:PEEK polymers are obtained by step-growth polymerization by the dialkylation of bisphenolate salts. Typical is the reaction of 4,4'-difluorobenzophenone with the disodium salt of...

) or synthetic body-own material (Hydroxylapatite
Hydroxylapatite
Hydroxylapatite, also called hydroxyapatite , is a naturally occurring mineral form of calcium apatite with the formula Ca53, but is usually written Ca1062 to denote that the crystal unit cell comprises two entities. Hydroxylapatite is the hydroxyl endmember of the complex apatite group...

). On the pictures a reconstruction using a titanium plate is shown. The skull contour has been restored.

Soft tissue defects

If the periosteum or underlying muscles (frontalis, occipitalis, temporalis) are intact, secondary closure by granulation is possible. Before surgical intervention this was the only option available, but aesthetically it nowadays would not be acceptable.The picture of Robert McGee illustrates this. A better option is the use of split-thickness or full-thickness skin grafts, which is quicker and gives more pleasing aesthetic results. When bulk is needed for a better contour a free flap is used, or as shown in the pictures, a regional flap.

Local reconstruction

If the skin defect does not exceed 3 cm in diameter, it can be closed primarily. If this is not possible without tension, the surrounding loose connective tissue can be undermined to attain more mobility. Different kinds of transpositions to close the defect with adjacent skin are possible: V-Y, Z, pinwheel flaps, advancement flaps, Orticochea flaps and rotation flap
Rotation flap
A rotation flap is a semicircular skin flap that is rotated into the defect on a fulcrum point. The flap must be adequately large, and a large base is necessary if a back-cut will be needed to lengthen the flap...

s. All these transpositions generate tension of the skin and may distort hair lines. A combination of the Orticochea and rotation flaps is illustrated by the pictures about the forehead defect.
Another option is secondary healing, but this is aesthetically inferior to primary closure in hair bearing areas because of the resulting alopecia. If the scalp cannot be closed primarily and local reconstruction with hair bearing skin is needed because of hair lines, tissue expansion
Tissue expansion
Tissue expansion is a technique used by plastic and restorative surgeons to cause the body to grow additional skin, bone or other tissues.-Skin expansion:...

 of hair bearing skin may be possible. The expansion process is uncomfortable on the short term, but long term results are good.

Regional reconstruction

If local reconstruction is not possible due to lack of local tissue, regional reconstruction is the next rung on the reconstructive ladder. This includes pedicled flaps as the trapezius or supraclavicular flap or tissue expansion of nearby regions. Alternatively, the Crane principle, as described by Millard
Ralph Millard
David Ralph Millard, Jr. was a plastic surgeon who developed several techniques used in cleft lip and palate surgeries. He was chief of the Division of Plastic Surgery at University of Miami's Miller School of Medicine for 28 years, and maintained a private practice in Miami.In 2000, Dr...

 in 1969, can be used. A healthy part is used to resurface the defect and when this flap takes, the skin is returned to its original site leaving the subcutaneous tissue on the defect, which then needs a split skin graft.

Skin grafts

If only skin is missing and underlying galea, muscle or connective tissue are intact, a skin graft can be used. A skin graft needs healthy, vascularised tissue beneath it to take, otherwise it will become necrotic.

Free flap

Free flaps are usually the best solution for reconstruction of large defects that cannot be closed locally and that have unfavourable wound conditions as severe infection, exposed sinuses, dura or brain tissue, CSF leakage or radiation damage. This method is the most complex of the reconstructive ladder
Reconstructive ladder
The reconstructive ladder is a term coined by reconstructive plastic surgeons to describe levels of increasingly complex management of wounds. The surgeon should start on the lowest rung and move up until a suitable technique is arrived at.-The ladder:...

. In scalp reconstruction free flaps have a great benefit because they are completely detached from their original location ("donor site") before transferal to the scalp which makes the inset easier compared to pedicled flaps. Another advantage is that free flaps provide a more robust vascular supply to the wound compared to pedicled flaps, controlling infection and radiation induced damage. In addition, muscle or myocutaneous free flaps provide additional bulk that obliterates empty spaces (e.g. exposed sinuses) and covers dura mater defects more than all other options, reducing postoperative wound infections and CSF leakages.
Disadvantages are the complexity of the operation, leading to prolonged operation times, the need for specialised personnel, and the chance for total flap necrosis due to microvascular complications. Another challenge with the use of free flaps is to achieve an aesthetically pleasing result with good color and contour match, especially if the defect is deep.

Outcome

Because the incidence of basal cell carcinoma
Basal cell carcinoma
Basal-cell carcinoma is the most common type of skin cancer. It rarely metastasizes or kills. However, because it can cause significant destruction and disfigurement by invading surrounding tissues, it is still considered malignant. Statistically, approximately 3 out of 10 Caucasians may develop a...

 and squamous-cell carcinoma is rising, there will be more need for reconstructions after radical excision of these skin malignancies. Reconstructive options depend on location and size. Most of the time the problem is not solved in just one operation, because small adjustments are necessary for good aesthetic results. Also further postoperative treatment modalities as radiation therapy
Radiation therapy
Radiation therapy , radiation oncology, or radiotherapy , sometimes abbreviated to XRT or DXT, is the medical use of ionizing radiation, generally as part of cancer treatment to control malignant cells.Radiation therapy is commonly applied to the cancerous tumor because of its ability to control...

 and chemotherapy
Chemotherapy
Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....

may impact the final result.

Aesthetic and functional

Temporal and forehead defects offer a more difficult aesthetic challenge and are best covered with a thin flap, so the aesthetic unit appears equal. Although the forehead is not an highly important aesthetic unit, color mismatch and bulkiness will draw attention quickly. Free flap reconstruction of the forehead can be bulky and color match is variable and depends on the ethnic and genetic background. Some people are not satisfied with the outcome and may experience psychological problems such as low self-confidence or even depression. Sometimes a second operation is needed to improve skin color. Overgrafting the skin with skin grafts from the scalp can improve color match.

Complications

Post-operative complications can be devided into donor-site and recipient-site problems. Donor-site complications include wound infection, hematoma, and seroma.
Recipient-site complications are (total or partial) flap necrosis, wound infection, dehiscence, hematoma or skin graft failure.
To avoid major bleedings or sensibility disorders, the anatomy of the scalp has to be respected. It makes a great difference if the incision is made parallel to the bloodvessel or right through it. Because of the high flow, scalp injuries can lead to serious bleedings. The cut vessels have the potential to retract into the fat so it is difficult to stop the bleeder.
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