Deformational (or positional) plagiocephaly refers to an asymmetrical shape of the skull from repeated pressure to the same area. Sometimes this can happen in the womb if the infant rest frequently in the same position. This is particularly true of breech babies, very large babies and multiple birth babies when one of the infants loses out on the real estate. More commonly, deformational plagiocephaly develops slowly over a period of several weeks following birth.
The incidence of plagiocephaly sky rocketed in the early 90's following the American Academy of Pediatrics recommendation that infants be placed on their back to prevent Sudden Infant Death Syndrome. When on their back, some infants develop a "position of comfort" keeping their head to the right or their left. Maintaining the head in one position results in flatness to the favored side. Larger babies often sleep laying directly on the back of their head resulting in a head shape that is flat on the right as well as the left.
Deformational plagiocephaly may not only cause flattening of the skull bones to the back of the head, other bones of the skull and face may also be repositioned. As pressure is applied posteriorly, deformational forces are directed towards the front of the skull and the forehead on the affected side may become more prominent. The bone which forms the forehead is called the frontal bone and it connects to the bone which forms the cheek called the zygoma. Together, the frontal and zygoma bones form greater than 75% of the eye socket (orbit). So as the bones that are primarily responsible for the structure of the orbit change position, the shape of the orbit is altered. Finally, when viewed from above, the ear of an infant with a deformational plagiocephaly may be shifted forward. This is called an "ear shear".
Congenital muscular torticollis may also play a role in the development of a deformational plagiocephaly. The term torticollis is derived from the Latin words tortus for twisted and collum for neck. Torticollis has several causes including congenital muscular torticollis which refers to the shortening or hardening of the sternocleidomastoid muscle. This muscle originates on the mastoid process located behind the ear. It then attaches to the collar bone. Tightness of the muscle results in an infant holding their head tilted to one side. The neck then develops a limited range of motion so when placed on their back the infant is "locked "into a head position which results in flatness on the affected side. Management of torticollis begins with early diagnosis. I often recommend an evaluation by a physical therapist experienced in managing torticollis. They will perform neck stretching and range of motion exercises and demonstrate to the parents how they can get involved on a daily basis. Consistency is very important. The majority of infants do very well with physical therapy alone. For those with limited success, it may be necessary to temporarily paralyze a portion of the sternocleiodomastoid muscle using Botox. The temporary paralysis decreases resistance from the shortened muscle and improves the neck's range of motion.
In my thirteen years as a craniofacial surgeon there have been only two instances when conservative treatment was not successful improving head position and range of motion. In both instances, surgical release of the neck muscle at its attachment to the collar bone was necessary to improve head position and a cranial molding helmet was used to correct skull asymmetry.
Management decisions for the treatment of deformational plagiocephaly are influenced by several factors. As I earlier mentioned, if torticollis is present, range of motion and neck stretching exercises should be initiated. If skull asymmetry is mild and detected early ( at two to four months) attempting frequent positional changes, tummy time and encouraging a head position opposite the side of flatness is reasonable. If the deformity is moderate to severe and a trial of repositioning has failed I may recommend a cranial molding helmet. The helmet applies gentle, persistent pressures to capture the natural growth of an infant's head, while controlling growth in the prominent areas and encouraging growth into the flat regions. The helmet is custom made using digital technology. The outside of the helmet is constructed of hard plastic and the inside lining is composed of a soft, durable foam. Frequent adjustments of the lining are required in order to accommodate the heads growth. The helmet is eventually worn 23 hours a day following a one week "break in period" when the number of hours that the helmet is worn increases daily. The average treatment time is usually three to six months, depending upon the severity of the asymmetry and the infants age when helmet therapy is started. When indicated, cranial molding helmet therapy should be initiated when an infant is no older than six or seven months of age. After six month the bones begin to thicken as estrogen from Mom starts to go away. Estrogen functions in early infancy to keep bones, cartilage, tendons and ligaments soft and pliable which helps during delivery. As estrogen leaves, bones thicken and cartilage becomes firmer. Tendons and ligaments strengthen. This is part of normal growth in preparation for the time when your child begins to walk. So getting an infant into their helmet when the skull bones offer minimal resistance is very important. Careful and frequent monitoring is important.
Positioning, physical therapy, and helmet therapy (when needed) will continue for the first year of the baby's life. During this period the brain and skull are growing rapidly and using these measures will provide the best chance of correcting the deformational plagiocephaly. Some cases do not require any treatment and the condition may resolve spontaneously when the infant begins to sit.
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