Transparietal/Transtemporal Distraction for Sagittal Craniosynostosis

Kristen Klement

Arlen Denny

DEFINITION

Sagittal craniosynostosis
- Premature fusion of sagittal suture. The sagittal suture normally fuses at an average of 26 years of age.
- Results in scaphocephaly. Scaphocephaly is an abnormal head shape with an increased anteroposterior dimension and narrowed bitemporal distance. This can also be associated with frontal bossing and occipital bulging.
Distraction¹
- Repositions cranial vault gradually
- Encourages intervening bony regeneration and decreasing bone grafts
- Mitigates extradural dead space
- Decreases blood loss
- Shortens operative time and hospital stay
- Promotes soft tissue acclimation
- Minimizes relapse
- Distraction is the ideal procedure in older infants and children.
  - Allows for better bone quality for mounting the distraction device
  - Decreases morbidity

ANATOMY

Cranial vault is a series of bones with junctions that constitute the cranial sutures (FIG 1).
The sutures are syndesmoses or a joint between cranial bones.

FIG 1 • Anatomy of normal skull bones and suture (left) and premature fusion of sagittal suture with resultant scaphocephaly (right).
- The major cranial sutures are metopic, sagittal, coronal, lambdoid, and squamosal.
Skull growth is normally perpendicular to sutures.
- Premature fusion results in compensatory growth parallel to the affected suture.
- Premature fusion of the sagittal suture results in scaphocephaly.

PATIENT HISTORY AND PHYSICAL FINDINGS

History
- Developmental delays and learning disabilities
- Behavioral issues
- Signs of elevated intracranial pressure:
  - Chronic headaches
  - Papilledema
  - Color visual impairment progressing to optic nerve atrophy
Examination
- Expanded anteroposterior dimension due to compensatory growth at the active sutures
- Narrowed bitemporal distance
- Sagittal ridge
- Frontal bossing due to fusion of the anterior sagittal suture and compensatory growth by coronal and metopic sutures
- Occipital bulge due to fusion of the posterior sagittal suture and compensatory growth by lambdoid sutures

FIG 2 • CT scan with 3D reconstruction of the head demonstrating premature fusion of the sagittal suture with scaphocephaly with expanded anteroposterior dimension, narrowed bitemporal distance, sagittal ridge, frontal bossing, and occipital bullet.

IMAGING

Computed tomography scanning of the head with 3D reconstruction (FIG 2) shows the classic findings in premature fusion of the sagittal suture:
- Expanded anteroposterior dimensions
- Narrowed bitemporal dimension
- Sagittal ridge at the site of the absent suture
- Frontal bossing
- Occipital bulge