SURGICAL ACCESSORY FOR USE IN IMPLANTING MEDICAL DEVICE
A surgical accessory for use in implanting a medical device in a cranial bone of a human patient may serve as a template during a craniectomy for cutting a hole in which a ferrule for a medical device may be situated and then secured. The surgical accessory is dimensioned to allow a surgeon to gauge how far above the outer surface of the cranium the medical device will extend once the ferrule has been secured to the outer bone table and the medical device has been cradled in the ferrule.
1 . A method for implanting an implantable medical device in the cranium of a patient, the method comprising:
tracing an outline of a surgical accessory on a top surface of the patient's cranium, wherein the surgical accessory includes a body dimensioned to approximate the dimensions of the implantable medical device including at least a depth, an outer perimeter, and a shape of a top surface of a housing of the implantable medical device;
forming a hole in the patient's cranium extending from an outer bone table through to an inner bone table of the cranium based on the outline;
situating a ferrule in the hole at a depth corresponding to the depth to which the ferrule extends from the outer bone table into the hole;
placing the surgical accessory within the ferrule; and
adjusting the depth of the ferrule based on the extent to which a top surface of the surgical accessory is or is not approximately flush with the outer bone table.
2 . The method of claim 1 , further comprising repeating the adjusting until the top surface of the surgical accessory when placed in the ferrule is approximately flush with the outer bone table.
3 . The method of claim 2 , further comprising:
removing the surgical accessory from the ferrule when the top surface of the surgical accessory is approximately flush with the outer bone table;
placing the implantable medical device in the ferrule; and
securing the implantable medical device within the ferrule.
4 . The method of claim 3 , wherein:
the body of the surgical accessory comprises an extension such that the outline upon which the forming of the hole is based comprises a notch that extends beyond the perimeter of the implantable medical device, and
securing the implantable medical device within the ferrule comprises installing a securing structure in the notch to engage the housing of the implantable medical device.
5 . The method of claim 1 , wherein:
the ferrule comprises at least one bendable tab,
situating the ferrule comprises bending the at least one tab to control the depth of the ferrule, and
adjusting the depth of the ferrule comprises rebending the at least one tab to change the depth of the ferrule.
6 . The method of claim 1 , wherein the body of the surgical accessory comprises an outward-facing surface having a curvature that matches the curvature of the top surface of the housing of the implantable medical device.
7 . The method of claim 6 , wherein the body of the surgical accessory comprises a bottom surface opposite the outward-facing surface of the surgical accessory, the bottom surface having a curvature that approximates the curvature of the outward-facing surface.
8 . The method of claim 1 , wherein the body of the surgical accessory comprises an outward-facing surface having a contour that matches the contour of the top surface of the housing of the implantable medical device.
9 . A method for using a surgical accessory in a procedure involving a cranially-implantable medical device, the surgical accessory provided with a body dimensioned to approximate the dimensions of an implantable medical device including at least a depth, an outer perimeter and a top surface of the implantable medical device, said method comprising:
tracing an outline of the surgical accessory on a top surface of the patient's cranium;
forming a hole in the patient's cranium extending from an outer bone table through to an inner bone table of the cranium based on the outline;
situating a ferrule in the hole, the ferrule provided with at least one bendable tab, situating the ferrule further comprising bending the at least one tab to adjust the depth to which the ferrule extends into the hole;
placing the surgical accessory within the ferrule;
assessing the extent to which a top surface of the surgical accessory is or is not approximately flush with the outer bone table; and
adjusting, if necessary, the depth of the ferrule until the top surface of the surgical accessory when placed in the ferrule is approximately flush with the outer bone table.
10 . The method of claim 9 , wherein the surgical accessory further comprises a pair of recessions provided in a top surface of the body configured to receive a surgeon's fingers or a surgical tool for grasping the body of the surgical accessory as necessary while it is being manipulated relative the patient, and further comprising using the pair of recessions to manipulate the surgical accessory relative to the cranium and the ferrule.