Metopic Synostosis Facts

The metopic suture is located on the midline, on top of the skull and extends from the soft spot to the root of the nose. Metopic suture synostosis is now the second most common type of single suture synostosis and predominantly affects males. Premature closure leads to a forehead that has the shape of a triangle and is known as trigonocephaly. The skull and forehead are not allowed to move sideways and forwards leading to closely placed eyes (hypotelorism). There is a low risk of abnormal brain growth and development. This form of synostosis is generally also easy to diagnose.

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The metopic suture is located in the midline and in front the soft spot as demonstrated by the red area.

The metopic suture extends from the soft spot all the way down to the root of the nose (nasofrontal suture) in the area between the eyes.

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The premature closure of the metopic suture prevents the front center of the skull from moving sideways and the front sides from  moving forwards (red arrows) The midline moves forward ( green arrow) causing a midline ridge and the classical triangular shaped head.

Presentation

The classical presentation consists of a prominent midline ridge and forward advancement of the mid forehead as seen in the images below. The eyebrows are  angulated and slanted and the eyes are close to each other leading to hypotelorism. If the head shape looks similar soon after birth and is due to fetal position or birth deformation, it corrects within a few days. If the baby's head shape persists after a few weeks, then it is most likely to be craniosynostosis.

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Radiology

Metopic synostosis is a clinical diagnosis, meaning that it is made by examining the patient and identifying the associated deformation of the head and face. CT  scans and X rays are not necessary to make the diagnosis. However, the images clearly show the skull changes related to this condition.

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Endoscopic Surgery

The goal of the surgery is to simply release and open the closed suture to allow the brain to resume its normal growth pattern and revert to a normal shape. Since the brain of an infant grows very rapidly, doubling in size during the first year of life, performing the procedure at an early age is of utmost importance. By using minimally invasive, endoscopic assisted techniques, such procedure can be done safely in very young babies. Once released, normalization of the head is aided with the use of custom made helmets (cranial orthosis) during the following year.

Positioning in Surgery

The patient is placed flat on the operating room table (supine position) with the head being placed on a specially designed head holder.

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Skin Incision

A single small (inch or less) incision is placed behind the hairline and in front of the soft spot. Only a small amount of hair is removed. The incision allows access to the entire suture, with the aid of endoscopes,  once a small opening is made in the skull.

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Craniectomy (Resection of skull) and removal of closed suture is done after cutting alongside of the stenosed suture. The bone is removed through one of the incisions. The closed suture is evident upon inspection. Once the prematurely closed suture is removed, the brain is allowed to grow as genetically programmed.

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Post Operative Swelling:

Contrary to CVR or FOA surgery, our patients experience minimal swelling of the face after surgery. Immediately after surgery, some swelling occurs as expected but it clears over the next 24-48 hours. There are no bruises and the eyes do not swell shut. Patients experience pain and discomfort for the first 8 hours which is controlled with Tylenol and Motrin. By the next morning, they are back to baseline, smiling and feeding well. All of the photographs below were taken on the first day after surgery and before being discharged to home.

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Post Operative Helmet Therapy:

The helmet DOES NOT constrict brain growth but rather redirects it and allows the brain to resume its normal shape. As such,  the skull and the rest of the face  also resume normal shape. In the case of metopic synostosis, the helmet holds the overgrown mid-forehead in place (white front arrow)  while allowing the recessed frontal bones (red lines) to expand forward (green arrows) and achieve correction. The prominent parietal areas are held in place as well. (White back arrows)

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CT Scans before and 3 years after endoscopic surgery for correction of metopic synostosis. The bone has fully regrown over the craniectomy site and the forehead has achieved normal shape. Once the head has normalized, there is no reason for relapse nor need of re-operation.

Metopic pre postCT

RESULTS 

Number of Patients:                                         141

Time Range:                                                    March 1998 to September 2017

Average Blood Loss:                                       32 ml's

Average Blood Transfusion Rate:                   6.1%

Average Length of Hospitalization:                 1.0 days

Average Surgical Time:                                   56 minutes

Number of Re-operations:                               None

Number of cases converted to CVR:               None