Norian CRS
Traumatic and surgically created defects in the craniofacial skeleton often require filling with a synthetic material for optimum clinical outcomes. Norian CRS (craniofacial repair system) offers a treatment solution for such cases. The Norian CRS family of products is completely synthetic self-setting calcium phosphate cements which closely resemble the mineral phase of bone. Once cured, both materials have identical chemistries and are gradually resorbed and replaced with bone during the bone remodeling process. The key difference between the two formulations is in the intraoperative handling and delivery properties.
Norian CRS is an injectable form of the cement which is mixed in the operating room using an automated mixing system. Once mixed, that material is transferred to a delivery syringe and injected into its intended site via a needle. These features make Norian CRS ideal for cases where delivery to a remote or deep site is necessary.
Features and benefits
The Norian CRS line of products hardens in a warm and wet environment, reducing the need to control moisture at the surgical site. The materials undergo in situ isothermal hardening, thereby eliminating thermal injury to the surrounding tissues. Both materials also achieve maximum compressive stress values which exceed that of native cancellous bone after 24 hours of hardening.
Clinical indications
Norian CRS is indicated for filling or repairing craniofacial defects and craniotomy cuts with a surface area no larger than 25 cm2. The material is also indicated for the restoration or augmentation of bony contours of the craniofacial skeleton, including the fronto-orbital, malar, and mental areas. The product is not intended for use in the spine, and should not be used in the presence of infection. Clinical procedures appropriate for the use of Norian CRS products include:
- Cranioplasty
- Cranial recontouring
- Cranial flap augmentation
- Augmentation genioplasty
- Onlay grafting
- Skull base defect repair
The application of the Norian products in layers is not recommended. Furthermore, they should not be used against an open sinus.
Figure Automatic mixer for Norian CRS.
Basic science
The Norian CRS bone cements consist of a carbonated apatite that more closely resembles the mineral phase of bone than hydroxyapatite. Hydroxyapatite is commonly thought of as the mineral phase of bone. However, it is the mineral dahllite that actually comprises 6070% of total dry bone weight. Dahllite has higher carbonate content (46%) than hydroxyapatite (0%). Therefore, as carbonated apatites with a carbon content of 5%, the Norian CRS products more closely resemble the composition of natural bone.
Figure Delivery of Norian CRS into a simulated cranial defect.
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