The present invention relates to implantable tissue and, more particularly to a system and method for making a calotte-shaped sheath of implantable tissue.
In various types of neurosurgery it is common to interpose a sheath of tissue between a patient""s brain and skull for dural substitution, such as for use in neurosurgical procedures. Typically the sheath is actual dura mater from a human cadaver that has been appropriately treated. Alternatively, a sheath of biocompatible tissue may be used.
Because certain curved shapes are difficult to reproduce, a generally flat sheath of biocompatible tissue typically used. Therefore, a new approach is desirable that is able to produce curved implantable sheaths, such as generally semi-spherical (or calotte-shaped) sheaths.
The present invention relates to system and method for making a calotte-shaped implantable sheath. A sheet of biological tissue, such as animal pericardium, is positioned onto a curved surface. A fixation solution is applied to a substantial portion of the tissue, as at least that portion is held generally flush against the curved surface. After the tissue has been appropriately fixed, peripheral portions of the sheath may be trimmed so as to form a calotte-shaped sheath of tissue suitable for implantation. The sheath conforms to the contour of the curved surface against which it was fixed. As a result, the sheath is able to conform to the shaped of a curved structure, such as an organ or brain, when implanted.
One aspect of the present invention provides a system for creating a calotte-shaped implantable sheath. The system includes a curved tissue-engaging surface and means for holding a sheet of biological tissue against the tissue-engaging surface during fixation. A volume of a fixation solution is operable to fix at least a substantial portion of the tissue substantially to the shape of the tissue-engaging surface.
Another aspect of the present invention provides a method for forming a calotte-shaped implantable sheath. A sheet of tissue is placed against a curved surface and fixed with a fixation solution while at least a substantial portion of the tissue is held against the curved surface so that at least that portion of the tissue conforms to the shape of the curved surface.