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Craniofacial Program

Unicoronal Synostosis

What is Unicoronal Synostosis?

Premature fusion of one (of which we have two) of the coronal sutures results in an asymmetric forehead and brow. It is the 2nd most common synostosis. Left sided unicoronal synsotosis is more common than right.

What Does It Look Like?

synostosis-uni1 image

You will notice on the affected side

  • The frontal bone (forehead) is flat and the supra orbital rim (upper orbital bone-where your eyebrow sits) and the lateral orbital rim (outer portion of the upper orbital bone) are recessed.
  • The Orbit is shallow. The eye appears more prominent.
  • An elevated sphenoid wing produces a Harlequin appearance giving the child an amused and or quizzical expression.
  • The root of the nose is often deviated to the affected side.

On the opposite side, the frontal bone may be bulging with the supra orbital rim and lateral orbital rim displaced anteriorly (towards the front) and inferiorly (below the level of the other). In other words, the        child with unicoronal synostosis
force of the growing and expanding brain causes the rest of the skull to compensate for the
lack of movement of the fused side. This results in the frontal bone on the unaffected side to become more prominent ( a term called bossing) while the eyebrow region appears drooped

It is often the appearance of this "normal" side that prompts parents to seek medical attention.

Does Unicoronal Synostosis Affect the Brain?

Craniosynostosis is known to be a cause of increased intracranial pressure and children with one prematurely fused suture, such as unicoronal synostosis, demostrate elevated intracranial pressure in >14% of cases. It is for this reason your child should be assessed by a team of specialists particularly those involved in the fields of Neuro-Ophthalmology, Neurosurgery and Craniofacial Surgery to test and evaluate whether increased intracranial pressure is a concern your child’s case or not.

Does My Child Need X-rays?


synostosis-uni2 image

Typically, most children do not need x-rays to diagnose unicoronal synostosis. A skilled clinician should be able to diagnose this condition with careful assessment of the skull.

However, a CT-Scan with 3D reconstruction will be used to:

  1. Verify the diagnosis of unicoronal synostosis.
  2. Assess brain growth and development.
  3. Assess if there is evidence of increased intracranial pressure.
  4. Assist in surgical planning if indicated.

What Happens in Craniofacial Clinic?

You and your child will meet the Craniofacial Surgeon and the Nurse Coordinator. The Craniofacial surgeon will either confirm or establish diagnosis and discuss the options available to you. Then a plan will be formulated that will involve you and your child meeting specific members of the team including but not limited to Genetics, Neurosurgery, Neuro-Ophthalmology, Occupational Therapy, and Social Work. A CT Scan will also be arranged. Once these assessments have taken place you will once again meet with the Craniofacial Surgeon who will discuss any further questions or findings, outline surgical options and expectations. Once a decision for surgery has been made then the Nurse Coordinator will discuss with you the preoperative planning including preoperative physical assessments, bloodwork, directed blood donation, length of stay, ICU stay, pain management, preoperative preparation of your child and programs available, expected post operative recovery course and follow up. These will be discussed with you in clinic and once again when a surgical date has been secured with the Craniofacial surgeon and the corresponding Neurosurgeon that you and your child have seen. The Nurse Coordinator will liase with any and all services both inside and outside of the hospital to ensure that all aspects of your childs preoperative work up are incorporated in the plan. The Nurse Coordinator will also be able to help you connect with other families who have recently gone through similar circumstances and surgery after their child was diagnosed with this type of synostosis.

Will My Child Need to Have Surgery?

Generally yes. The impact of unicoronal synostosis on the facial skeleton and its development warrants surgery in early infancy. If untreated , unicoronal synostosis will result in severe deformity of the forehead, orbit and nose that will persist and or worsen with continued growth. Also, untreated unicoronal synostosis, if severe enough, will affect your child’s occlusion (the way the jaw and teeth fit together) and possibly chewing, speech and lower face development.

What Does Surgery Entail?

The surgical correction of unicoronal synostosis is performed with a Cranio Orbital Reconstruction (approximately 6 hours in length) at approximately 10-12 months of age. This surgery involves the reconstruction of the frontal bones (forehead) and of the upper orbits (supra orbital rims) into a more aesthetically and functionally correct position.

Via a coronal incision, the skull bones are cut and separated from the brain and reshaped. The synostosed portion of bone is removed and the forehead and the upper bone portions of the eye sockets (supra orbital rim) are reconstructed and moved forward. Bone pieces are held in place with plates and screws (usually bio-resorbable ones). Usually, there is not enough bone to reconstruct the entire surgical area and several ‘soft spots’ remain which will heal spontaneously over time. This phenomenon, of the skull laying down new bone, takes place until approximately 18-24 months of age.

CT scan and picture of child after surgery for unicoronal synostosis. CT scan 1 year after surgery

For those children older than 2 years of age a second procedure is often needed to address any bony defects left after a Cranio-orbital Reconstruction.

Blood Transfusion. Is It Necessary? Can We Donate?

Your child will require 2 units of blood to be available for this surgery. You will have the opportunity to be a directed donor of your blood if you or your spouse are

  1. Compatible with your child
  2. Healthy
  3. Meet the criteria of the Canadian Blood Services
  4. If you are not, we will utilize the blood from the volunteer blood supply from The Canadian Blood Services. The Nurse Coordinator will speak to you more about this and the process involved in getting screened and tested and what is required to donate blood for your child. Once donated, blood has a shelf life of approximately 35 days. Thus, most parents will be donating units within one and two weeks of the surgical date.

After Surgery

Following surgery, infants and children generally stay overnight in our Pediatric Intensive Care Unit. From there they will be transferred the following day to the Plastic Surgery Unit (8C) where they will generally stay for 3-5 days. Before discharge all children will have a postoperative CT Scan. Children and families will then be followed up by the Craniofacial Surgeon in the Craniofacial Clinics one week after discharge.