Silk Devices for Cranial Fixation - a Protective Shield to Brain After Neurosurgery

Date:04-04-2018   |   【Print】 【close

Cranial fixation has been a standard neurosurgical procedure for cranium remodeling in neurosurgery. Titanium or steel devices, including screws, plates and wires, are commonly used to re-fix the bone flap as permanent implantations. However, the metallic devices remain side effects, such as temperature sensitivity and tactile sensation, which result in discomfort for the patients. In addition, metallic devices may even induce localized inflammation or chronic infection at 8-11% cases in which a second operation is needed to remove the devices.

Recently, Tiger H. Tao and co-workers reported a silk cranial fixation system. The system includes silk screws and strips to anchor the bone flap, which are fabricated from natural silk proteins obtained from cocoons of the Bombyx mori silkworm. The silk devices can be used to provide a protective shield to brain after neurosurgery.

Silk materials are renowned for its superior mechanical properties, outstanding biocompatibility, programmable biodegradability, and facile incorporation of therapeutic components. Tiger H. Tao and co-workers extracted natural protein from the silk cocoons and reshape it into surgical screws and strips. Meanwhile, mechanical properties and in-vivo degradation behaviors of the silk devices were optimized for ideal cranial fixation by modulating the protein molecular structure. The team also demonstrated facile load of antibiotic medicine into the silk devices and testified the antibacterial function in rats.

The silk devices also show advantage in perfect compatibility with medical electro/magnetic examinations including MRI and CT scans, compared to metallic devices. Typically, 1.5T and 3.0T MRI scanners and even the state-of-the-art 7.0T ones are widely used after neurosurgery.

The team administrated preclinical tests of the silk devices in dogs for up to 12 months. Bone flaps were removed and replaced with the silk screws and strips anchored. The silk cranial fixation system shows favorable biocompatibility without any adverse immune responses. Complete reconnection of the bone flap with skull bone was achieved after 1 year. Meanwhile, stress shielding, which has been a negative side effect for metallic implants, was avoided by using the silk-based fixation system. Preclinical studies suggest that the silk device shows a promising perspective in neurosurgery.

The work was published in Advanced Healthcare Materials as a back-cover story