Cranial Reconstruction Using Mesenchymal Stromal Cells and Resorbable Biomaterials

Formal study hypothesis:

Cranial reconstruction using mesenchymal stromal cells and resorbable biomaterials, will result in the patient producing their own bone to fill the void which will reduce the risk of infection and resorption, lead to a better cosmetic result and obviate any long term consequence of having a synthetic material in vivo.

Introduction:

There are several reasons that parts of the skull may need to be removed:

• After trauma to relieve brain swelling
• During brain surgery (for brain cancer)
• After trauma where the bone is so badly fractured/fragmented it needs to be removed.

In all but the last case the bone flap is temporarily stored in a freezer and once the brain swelling has subsided it is reinserted. This procedure is called "autologous cranioplasty"; autologous, because it originally came from the patient and cranioplasty, referring to the repair. Although this is a straightforward procedure, there are a number of complications including infection and bone resorption that can occur.

This study:

Stromal cells have a proven ability to aid in bony healing. Furthermore stromal cells on a ceramic framework encased in a plastic scaffold have been shown in a small clinical trial to lead to healing of skull defects. In the present study, it is proposed to add stromal cells from a suitable donor to medical grade ceramic granules, place them in between specially moulded plastic scaffolds and insert the sandwich into the skull. Both the ceramic and plastic materials are medical grade and commonly used in reconstructive surgery, the ceramic for packing into bony defects due to trauma or removal of cancer and the polymer in bony reconstruction. Both materials are approved by the TGA. They are designed to dissolve away over time as the body's own blood vessels and cells populate the sandwich and create the patient's new bone. It has been proven that without the encouragement of the cells and temporary scaffold materials, a hole in the skull will not heal. Given the incidence of bone resorption/infection and metal plate infection using traditional methods, it would seem prudent to provide a construct that will allow controlled replacement with the patient's own bone, thus negating any adverse long-term complications with synthetic materials that remain for life.