Pediatric Neurosurgery

PEDIATRIC SKULL MOLDING

NEWBORN CRANIAL ANATOMY

Infant's skull is made up of free-floating bones separated by fibrous sutures.

Allows the head to pass through the birth canal and also enables the skull to grow during infancy.

CRANIAL ANATOMY

NEWBORN CRANIAL ANATOMY

  • Infant's skull is made up of free-floating bones separated by fibrous sutures.
  • Allows the head to pass through the birth canal and also enables the skull to grow during infancy.
  • As the brain grows, the sutures allow for rapid expansion ‐ in a symmetrical manner.
  • The brain determines the head size and shape under normal circumstances.
  • 85% of postnatal skull growth occurs during the first year of life.
  • The symmetrical helmet creates a pathway for growth to occur.

HEAD GROWTH

  • Head circumference increases from 35cm to 47cm during the first year of life
  • Brain volume doubles in the first year of life
  • Head growth slows dramatically after the first 12-18 months of life
  • During the first 12-18 months of life, most head growth is accomplished by expansion along suture lines
  • Thereafter, the skull grows by internal resorption and external replacement

ETIOLOGY OF CRANIOSYNOSTOSIS

  • Unknown in sporadic cases
  • All have a familial tendency
  • Most felt to be secondary to a defect in fibroblast function

CRANIOSYNOSTOSIS

  • Single suture synostosis is rarely associated with intracranial anomalies.
  • It is a primarily cosmetic issue as brain volume is maintained by abnormal skull growth.
  • However, there is a 10-15% incidence of elevated intracranial pressure in untreated craniosynostosis.
  • The sooner craniosynostosis is addressed, the better the cosmetic outcome.
  • Conversely, the sooner craniosynostosis is addressed, the more likely the patient will require a second operation.
  • TRUE SYNOSTOSIS OCCURS IN 5 / 10,000 LIVE BIRTHS

SUTURES

INCIDENCE

  • SAGITTAL       50%
  • CORONAL      25%
  • LAMBDOID   10-15%
  • METOPIC      10-15%

SAGITTAL SYNOSTOSIS AKA SCAPHOCEPHALY

  • INCIDENCE: 2 / 10,000 live births
  • “Keel” deformity
  • Rarely associated with skull base or facial abnormalities

CORONAL SYNOSTOSIS

  • INCIDENCE: 1 / 10,000 live births
  • “Harlequin” eye with unilateral coronal synostosis
  • Invariably associated with facial and occasionally skull base anomalies
  • Present in Apert's, Crouzon's, and Pfeiffer's syndromes

APERT'S SYNDROME

  • Acrocephalosyndactyly
  • Uncommon - usually sporadic but autosomal dominant transmission occurs
  • Proptosis, high arched palate, complete symmetric syndactyly of fingers and toes, mental retardation
  • Phenotypically similar to Crouzon's

CROUZON'S SYNDROME

  • Most common of the craniofacial dysmorphic states
  • Autosomal dominant transmission
  • Proptosis, midface hypoplasia, usually cognitively intact
  • Similar to Apert's but smarter and no syndactyly

PFEIFFER'S SYNDROME

  • Autosomal dominant transmission
  • Proptosis, mid-face hypoplasia, mild syndactyly
  • Phenotypically midway between Apert's and Crouzon's

CARPENTER'S SYNDROME

  • Autosomal recessive transmission
  • Syndactyly, mental retardation, congenital heart defects
  • Most common of the autosomal recessive craniofacial dysmorphic states

METOPIC SYNOSTOSIS AKA TRIGONOCEPHALY

  • INCIDENCE: 0.5-1/10,000 live births
  • “Beaked” forehead
  • First suture to close physiologically (3-5 months of age radiographically)

LAMBDOID SYNOSTOSIS AKA PLAGIOCEPHALY

  • INCIDENCE: 0.5-1/10,000 live births
  • Clinical and radiographic distinction from occipital molding

Plagiocephaly and Brachycephaly

OCCIPITAL FLATNESS aka POSITIONAL MOLDING

  • Treatment of choice is an occipital molding helmet, the price of which has dropped from >$5000 5 years ago to $1500 today
  • Difficulty with education of payors
  • Improves cosmetic outcome from 40% acceptable to 80% good

Occipital Molding

Positional Plagiocephaly

ABNORMAL HEAD SHAPE

Largest group of infants with abnormal head shape have positional deformities which develop during pregnancy or sleeping.

“Back to Sleep” Program

Because of a higher incidence of SIDS with babies who sleep prone, it was recommended in 1992 by the American Academy of Pediatrics that babies be put to sleep on their backs.

This has resulted in about 1 in 100 babies developing positional plagiocephaly from the infant sleeping in the same position most of the time.

If a little will do good...

... A lot must be better?????

Coupled with torticollis, positional plagiocephaly has skyrocketed since 1992.

Misdiagnosis of Plagiocephaly

Initially, some of these infants were misdiagnosed with craniosynostosis and underwent corrective surgery to correct the problem.

Causes of Positional Plagiocephaly

  • Sleeping positions
  • Premature births (NICU positioning)
  • Torticollis
  • Restrictive intrauterine positioning
  • Cervical abnormalities
  • Birth trauma

OCCIPITAL MOLDING BANDS

Treatment Protocols

After first diagnosed with positional plagiocephaly, the family is given stretching exercises, instructions to alternate positioning, and physical therapy if the child has torticollis.

If there is no change with this treatment, or if the child is too old to be repositioned (5-6 months of age), orthotic management is the next step.

Contraindications

  • Craniosynostosis
  • Hydrocephalus
  • Children younger than three months

Orthotic Management

  • Stockinette is applied over the baby's head with a hole cut out for the face
  • A series of plaster splints are applied to the head from the eyebrows to the back of the neck (i.e. bivalved cast).
  • The cast is removed.
  • Family continues “home therapy program” (i.e. stretching exercises and repositioning) throughout the entire process.

Preparation for casting

Stockinette cap applied.

Note: Stockinette must be pulled down over eyebrows for casting.

American Academy of Pediatrics ‐ 1997 Varying position reduces head ‘molding’

  • “Parents might not realize that a baby may lie prone when awake, experts say.”
  • “Babies should be spending time on their stomachs,” Dr. Kattwinkel said. “It's just when they're put to sleep that they should be on their backs.”

Graham, J.M.

  • Infant Sleeping Position and Sudden Infant Death Syndrome (SIDS)
  • “Supine sleepers attain several motor milestones later than prone sleepers (rolling prone to supine, tripod sitting, creeping, crawling, and pulling to stand), however all milestones are eventually attained within the expected normal range.”
  • Encouraging “tummy time” during waking hours (with observation) helps to minimize these differences in normal motor development.

Marshall, Fenner, Wolfe & Morrison ‐ 1997

Algorithms for Treatment