Craniosynostosis & Plagiocephaly (Skull Abnormalities)

CRANIOSYNOSTOSIS

Overview

The infant skull is made up of a series of bones that are connected by fibrous tissues called cranial sutures. These cranial sutures are the growth centers of the infant skull.

Growth occurs perpendicular to these cranial sutures, allowing the skull to expand. This growth is critical as the infant brain grows to approximately 60% of its adult size in the first year of life.

Craniosynostosis is the premature fusion of a cranial suture, occurring in 1 out of every 2000 births. Because of this fusion, there is a “sticky point” that does not allow the infant’s skull to grow normally. As a result, growth occurs parallel to the point of synostosis. Because craniosynostosis both leads to an abnormal appearance and can put pressure on the growing brain, you should consult a trained, craniofacial surgeon as soon as possible.

Depending on which cranial suture or sutures have fused, the head shape can take on a predictable and recognizable pattern of head deformation.

SCAPHOCPHALY: SAGITTAL SUTURE
Scapho meaning: BOAT

PLAGIOCEPHALY: UNILATERAL CORONAL
Plagio meaning: OBLIQUE, TWISTED

TRIGONOCEPHALY: METOPIC SUTURE
Trigono meaning: TRIANGULAR

BRACHYCEPHALY: BILATERAL CORONAL
Brachy meaning: FLAT

LAMBDOIDAL: POSTERIOR PLAGIOCEPHALY
This means that there are multiple fused sutures creating what is commonly referred to as a “clover leaf deformity”.

Diagnosis and workup

Craniosynostosis usually manifests as an abnormal head shape at birth that worsens with time. This is different from deformational plagiocephaly which typically improves with time. Early recognition of an abnormal head shape that does not fit the typical pattern of positional plagiocephaly is vital in minimizing long-term issues related to craniosynostosis.

If craniosynostosis is suspected, the infant should be evaluated by a trained craniofacial surgeon as soon as possible.* In addition to a comprehensive medical history review and physical exam, the surgeon may choose to obtain a CT scan which serves as an objective and definitive measure to detect the presence of craniosynostosis.

*If you suspect any issues or abnormalities with your child’s head shape, consult a trained craniofacial surgeon immediately.

What are the Risks of Untreated Craniosynostosis?

Intuitively, it would make sense that with the infant skull not expanding at the same rate that the brain is growing, then there would be a risk of pressure on the infant brain. This is referred to as an increase in intracranial pressure. The risk of increasing intracranial pressure, as it relates to craniosynostosis, is dependent on if one or more sutures are effected. If one suture is involved, the risk of intracranial pressure is approximately 20%. This risk increases to nearly 50% if multiple sutures are involved. The reported risks are cognitive delays, visual impairment, and neuropsychiatric disorders. These risks have been reported to be significantly reduced if the offending sutures are removed and/or the skull is expanded. (1)

Timing of Surgery and Surgical Options

The goal of surgery is to remove the fused cranial suture (with or without cranial remodeling) to allow the brain to grow without restriction and to reverse the cranio-orbital deformity. The type of reconstruction offered is dependent on the severity of the deformity, the type of craniosynostosis, and the patient’s age at the time of surgery.

Option #1

Endoscopic minimally invasive strip craniectomy

This surgical option is very effective if the child is diagnosed and evaluated by a craniofacial surgeon before they are 3 months old. With this technique, the fused cranial suture is removed though a small incision(s). Following the procedure, the child is placed in a custom cranial-molding helmet to mold the head into a more normal shape over time.

The advantages of this technique are smaller scars, shorter hospital stay, potential for less blood loss, and less post-operative swelling. The disadvantage is that the deformity takes more time to correct. But if this procedure is done early in life, the long-term results are comparable to more traditional techniques.

Option #2

Traditional cranial vault remodeling

This operation is typically performed when the infant is between 4 and 8 months of age. With this technique, the fused suture is also removed. In addition, the deformity in the head shape is corrected during the surgery. So, when the surgery is done, the child’s skull will appear to have a normal shape.

The major advantages of this technique are that the anatomical deformity is corrected immediately following the surgery, there is no need for a post-operative helmet, and it provides a better long-term result for infants that missed the window of treatment before becoming 3 months old. The disadvantages are a larger scar in the hair bearing scalp, greater potential for blood loss, and a somewhat longer hospital stay.

Summary

Craniosynostosis is the premature fusion of a growth center in the infant skull that results in predictable patterns of head deformity. Early recognition of an abnormal and worsening head shape is essential, and it should be followed by an evaluation and discussion with a trained craniofacial surgeon. Consult a trained craniofacial surgeon as soon as possible if you believe that there may be an issue with your infant’s head shape.

Craniosynostosis

Deformational PLAGIOCEPHALY

Plagiocephaly – literally means “oblique head” (from the Greek words “plagio” for oblique and “cephale” for head). This is most commonly caused by positioning of the head, but it may also be caused by craniosynostosis, a more serious condition. A child with plagiocephaly should be evaluated by a craniofacial surgeon immediately to make this distinction.

What is positional plagiocephaly?

Positional plagiocephaly is a deformation of the child’s head shape that is caused by repeated pressure being placed on an area(s) of the head. This positioning may be a result of Torticollis (a condition where certain muscles controlling the neck undergo repetitive or sustained contraction, causing the neck to jerk or twist to the side), eye abnormalities, or more commonly, from positioning a child on their back as recommended by the “Back to sleep campaign”.*

NOTE: Back sleeping is essential for your child’s safety. Do not stop back sleeping for your child. Consult a craniofacial surgeon for treatment to help Plagiocephaly.

How is deformational plagiocephaly different from craniosynostosis?

Craniosynostosis is the premature fusion of one or more of the sutures in the skull. True craniosynostosis may limit the size of the skull, and therefore impede brain growth. The diagnosis is made after a clinical evaluation by a craniofacial surgeon and/or a neurosurgeon. X-rays and CT scans of the head may be performed to confirm the diagnosis of craniosynostosis. Surgery is usually the recommended treatment. (See the section above on Craniosynostosis or by clicking here)

In deformational plagiocephaly, there is no fusion of the skull sutures. It is a clinical diagnosis made after a thorough medical history and physical examination by a craniofacial surgeon and/or neurosurgeon. X-rays and/or CT scans are usually not necessary. Treatment of deformational plagiocephaly generally includes positioning and/or helmeting.

The major differences between craniosynostosis and deformational plagiocephaly are summarized in the chart below:

*Back sleeping is essential for your child’s safety. Do not stop back sleeping for your child. Consult a craniofacial surgeon for treatment to help Plagiocephaly.

What causes deformational plagiocephaly?

By keeping an infant’s head in one position for long periods of time, the skull may flatten from the external pressure being put on it. Occasionally, a baby is born with this flattening of the head because of a tight intrauterine environment (e.g., in multiple births, small maternal pelvis, or with a breech position). Other factors which may increase the risk of deformational plagiocephaly include the following:

muscular torticollis — Muscular torticollis is a congenital (present at birth) finding in which one or more of the neck muscles is extremely tight, causing the head to tilt and/or turn in the same direction. Torticollis is often associated with the development of plagiocephaly because the infant holds his/her head against the mattress in the same position repeatedly due to the tight neck muscles.
prematurity — Premature infants are at a higher risk for plagiocephaly since the hardening and the strengthening of the cranial bones occurs in the last 10 weeks of pregnancy. Also, since many premature infants spend extended periods of time in the neonatal intensive care unit (NICU) on a respirator, their heads are maintained in a fixed position, increasing the risk for this condition.
back sleeping* — Infants who sleep on their backs or in car seats without alternating positions for extended periods of time are also at a higher risk for deformational plagiocephaly.

Treatment for deformational plagiocephaly:

The course of treatment for your child’s deformational plagiocephaly will be determined by your child’s physician, and it will be based on the specific nature and severity of your child’s case of plagiocephaly. Frequent rotation of your child’s head would be the first recommendation once your infant has been diagnosed with plagiocephaly. Alternating your infant’s sleep position from the back to the sides, and not putting infants on their backs when they are awake may also help prevent and treat positional plagiocephaly. Some cases do not require any treatment, and the condition may be resolved when the infant begins to sit.

If the deformity is moderate to severe, and a trial of re-positioning has failed, your child’s physician may recommend a cranial remodeling band or helmet.

How does helmeting correct deformational plagiocephaly?

Helmets are usually made of an outer hard shell with a foam lining. Gentle, persistent pressures are applied to direct the natural growth of an infant’s head, inhibiting growth in the prominent areas and allowing for growth in the flat regions. As the head grows, adjustments are made frequently. The helmet essentially provides a tight, round space for the head to grow into.

How long will my child wear a helmet?

The average treatment with a helmet typically lasts three to six months, depending on the age of the infant and the severity of the condition. Careful and frequent monitoring is required. Helmets must be prescribed by a licensed physician with craniofacial experience.

References

Intracranial pressure in craniostenosis. – Renier D; Sainte-Rose C; Marchac D; Hirsch JF – J Neurosurg – 01-SEP-1982; 57(3): 3

Congenital Synostoses Frank S. Ciminello MD, and S. Anthony Wolfe MD, FACS eMedicine,

Craniofacial Distractor Applicator Dorfman DW, Ciminello FS, and Wong GB J Craniofacial Surg. 20(2) pgs 475-477, 2009

Craniosynostosis & Plagiocephaly (Skull Abnormalities)