| Craniofacial Team |
| Craniofacial Center Members |
| Cleft Family Information |
| Craniofacial Anomalies |
| Children's Medical Center |
By Christine Deriso
Note: This article appeared in the Fall 1997 Issue of MCG Today.
If you were to look through an electron microscope at key junctures of a baby's developing skull, you would see what Dr. Jack Yu likens to the view of a bustling city from space.
"You have a piece of bone that tapers to a leading edge, then another piece of bone which comes to a tapered edge and then, around here, cells are working very hard," said Dr. Yu, Director of the Medical College of Georgia Craniofacial Center.
The cellular bustle is about building bone for a strong skull to protect the brain. The
work goes on in the first months and years of a child's life in areas called cranial
sutures. A baby's skull has many sutures; 'soft spots,' as they are commonly called, are
where the sutures meet. About one in 2,000 times in the complex process that takes 23
chromosomes from each parent to make a unique human being, there is an error as the genes
these chromosomes carry are copied. The result is that the bustle stops too soon at one or
more of these sutures.
Kevin Bloodworth's father didn't need the power of an electron microscope to see that something wasn't quite right with his son.
When he'd hold his second son in his lap and look down at his head, he could see Kevin's right eye, but not his left. Gene Bloodworth thought one eye was swollen; the truth was the other was sunken in.
Kevin's left coronal suture, located at the left corner of a diamond-shaped soft spot normally found on top of a baby's head, had closed prematurely. So Kevin's head had a twisted look; the left side of his forehead was pushed back and his left eye socket was distorted, both results of the premature closure on the left and nearby viable suture trying to compensate for the loss.
"The brain grows rapidly at this young age, and it's going to grow no matter what, so it's going to find where it can grow," said Dr. Mark Lee, Kevin's pediatric neurosurgeon and a member of the MCG Craniofacial Center Team. Even a single suture closing, such as in Kevin's case, throws off the dynamics of the skull growing to accommodate the growing brain. The result is the loss of facial symmetry and sometimes much more.
"When many skull sutures are closed at the same time, the skull bone is not
expanding in pace with the brain," Dr. Yu said. If one or two sutures are involved,
distortion of the face is the primary result. But form and function are closely linked;
when there are too many problems with form, the brain and its endless functions are
jeopardized. Intracranial pressure rises when the skull refuses to yield to the growing
brain, potentially damaging the baby's brain, vision, hearing, speech and even the ability
to breathe.
"The first order of business is the preservation of life, then preservation of key organs," Dr. Yu said.
At the MCG Children's Medical Center, a diverse team of specialists looks after the
compelling and complex needs of these children. The assemblage includes pediatric
neurosurgery, pediatric otolaryngology, pediatric ophthalmology, pediatric radiology,
pediatric nutrition, child psychiatry, neonatology, orthodontics, pediatric dentistry,
pediatric critical care, speech pathology, audiology and genetics counseling. Erika
Doster, physician assistant, is team coordinator and an accessible contact
for families and referring physicians.
"This team is the essence of collaboration," said Dr. Ann Flannery, pediatric neurosurgeon. Team members gather on the third Wednesday of each month, see the children and their parents individually, then collectively devise a treatment plan.
Dr. Flannery cites common issues the team tackles: "When are we going to fix it? What is the sequence? Does the child need braces? Is it time for a mid-face advancement? How are the eyes doing? Do they need to be reset? Do they require strabismus surgery? Are they having otitis? Do they have a tracheostomy in? Can it come out? What is their speech like?"
Parents come that day with just as many questions. One very common question is, "Why?"
"We can answer 'how' a little bit better than 'why,'" Dr. Yu said. "The suture (or sutures) for a whole host of reasons become non-existent. So instead of having two pieces of bone which have the ability to move relative to each other, they essentially become one bone." The eventual goal is for the suture to become bone, but for these children, the goal is reached before the game is over.
"Brain growth pretty much should parallel the growth of the head--extremely rapid in the first six months of life, less rapid but still growing in the next 12 months and slowing down but still growing to at least age 3," Dr. Flannery said. If you examine the adult skull, you can see the fine lines where the sutures turned to bone.
The skull is rather unusual in that it's non-weight-bearing yet stays strong, unlike body bones which can become frail when inactive. Its very origin also is different. Skull bone is made by the dura, the multi-layered protective covering of the brain that resembles supple leather. The inner layer has cells that look not like bone cells but like cartilage cells in an area that supposedly has no cartilage, Dr. Yu said. "Those cartilage cells may be the ones that tell the bone, 'Don't make bone here. We are a suture. We are supposed to be here.'" A second cell type has fibers that are stretched as the brain grows and apparently signal the cells to produce a substance to prevent bone formation until the brain is finished growing.
Communication and regulation is central to this active cell community charged with building a skull on schedule. When Dr. Yu isn't treating patients, he's working in the laboratory to understand how these cells know what to do, when to make bone and when not to. "The underlying cellular process, cell function, the control of cell function and regulation--that is the gist of biology in the 21st century," he said.
But for now, he and other members of the craniofacial team try to help parents understand what has happened and how best to correct what has gone wrong.
"We had to do a lot of soul-searching on this," Kevin's father said. "Our number-one concern was his brain." Dr. Yu told Mr. Bloodworth and his wife, Janet, that although their child's brain was not in jeopardy, the twisted look of his face would only get worse.
"I looked at it as later on, if we chose not to do anything, would he look at me and say, 'Daddy, why didn't you have something done when you could?' It would be hard to answer that question." So Kevin's parents searched the Internet for information and their hearts for the right answer.
Drs. Yu and Lee worked together on what should be Kevin's only craniofacial procedure. First Dr. Yu removed the skin covering Kevin's forehead, making wavelike incisions in the hairline and behind the ear that reduce tension and will be virtually unnoticeable, even when his hair is wet. He then stripped the temporalis muscle, the major closing muscle of the jaw, to access the bone.
Next Dr. Lee began the delicate job of removing the forehead bone, down to orbital rim in the eyebrow, without injuring the brain or important blood vessels. He then cut it into appropriate pieces for Dr. Yu to refashion into a more desirable shape.
Decisions about how far to project the new forehead are based on specific measurements called cephalometrics, standard norms for head measurements that are age- and race-related. "We cannot recreate sutures," Dr. Yu said. "What this operation is designed to do is to relieve the constraint and project this piece of bone out to symmetry." The newly placed bone is secured with durable, dissolving thread resembling fine fishing wire. New bone will move into the area and eventually fill the gap.
Timing and order are key factors for repairing craniofacial defects. "For reasons we don't completely understand, if you do this operation, if you somehow tip the balance at a crucial time which is about 6 to 12 months, 90 percent of them don't have to have more surgery," Dr. Yu said of children, such as Kevin, whose defects involve a single suture. Before age 6 months, the dura can reform bone and may recreate the fusion that the child had surgery to repair, Dr. Lee said.
In more complex cases, the care may begin literally in the first few days of life with brain-protecting measures such as temporary shunts to relieve intracranial pressure and a tracheostomy to ensure adequate respiration.
The eyes are the next point of focus. Dr. Steven Brooks, pediatric ophthalmologist, thoroughly examines the patients, checking vision, eye movement and eye anatomy. Unchecked, increased intracranial pressure can injure the optic nerve and damage or even destroy vision. Some of these children have weakened or absent extraocular muscles, which control eye movement. This may result in crossed eyes, or strabismus, that needs correction, Dr. Brooks said. Multiple suture closings can result in underdeveloped orbits leaving the eyes literally bulging, unprotected out of their sockets. Dr. Brooks sometimes needs to suture portions of the eyelid together to help keep the eyes moist and covered until the craniofacial team can rebuild the area with more definitive surgery.
Dr. John Bent, pediatric otolaryngologist, helps assess whether pressures or malformed ears have damaged hearing. Craniofacial abnormalities, such as a small jaw and large tonsils, may result in breathing problems. A tonsillectomy and adenoidectomy may alleviate the problem, but Dr. Bent also can assess whether a procedure to pull the mandible forward is needed.
Speech pathologist Andrea Glover assesses the children's verbal skills to see if they are on target. If not, a hearing problem is the likely cause. If there's good comprehension and expression, she looks at individual speech sounds, voice quality and resonance.
In the midst of all the efforts to correct what is wrong, genetics counselor Heather Radtke helps parents understand as much as possible about how it went wrong.
"A lot of people have guilt issues and blame issues," she said. "What we do in that situation is go through, specifically, any type of exposure and medication and what we know about them. A large part of my job is helping parents understand that it's nothing that they did."
In families such as the Bloodworths, who have no known family history of premature suture closures, Kevin's defect is considered an unpreventable fluke. "We can't say specifically why gene changes occur," Mrs. Radtke said. "But we know that the human body is very complex in how it develops and that when the genes are being copied into the egg and the sperm, mistakes can occur."
Dr. Yu can tell you that if Kevin's father had been born with such a mistake, he would have had to live with it; craniofacial surgery is only 25 years old in this country.
He'll also tell you that today, 15-month-old Kevin stands an awesome chance of looking as though he never needed it.