AU2011100697A4 - Template Cranioplasty - Google Patents

Abstract

Abstract The following invention describes the technique and devices required to perform template cranioplasty surgery. The technique requires the surgeon to place a thin pre fabricated cranial prosthetic implant over a craniotomy defect. The implant can float between the patients skin and skull to allow intracranial compliance if brain swelling occurs after surgery. Once brain swelling subsides the implant comes into approximation to the skull. A second stage procedure can then be performed to fix the implant to the skull Step 1 At the time of craniotomy a template is applied to the skull. The outline of the craniotomy is traced on the skull using marking pen, score or diathermy. Step 2 A preformed malleable prosthetic implant is shaped to the skull using pressure and radial force to mould the implant to the contour of the skull. Step 3 The craniotomy is performed using standard technique. Step 4 The preformed malleable prosthetic implant (with a degree of overlap) and multiple fixation tabs is then placed over the craniotomy defect. One tab may be used to fix the implant to the skull with suture or a screw. Step 5 The wound is closed Step 6 As the implant is not securely fixed to the skull if the brain were to swell the implant can allow compliance. As the implant is of significantly less volume than the bone flap that has been removed a greater volume of space will be available to facilitate compliance. Step 7 Once the brain swelling subsides the implant may then be fixed by screws via small stab incisions The invention consists of four separate components. Firstly a template that approximates the skull. Secondly a marking device that can be used to mark around the edge of the template. Thirdly a preformed malleable implant. The implant is manufactured to be thin so that it will have substantially less volume than the bone it replaced. The material is such that it is preformed but can be shaped to a final form intra-operatively by applying pressure and radial force to the implant as it is held in approximation over the skull. The implant is shaped so that it contains tabs that overlap the skull so as to prevent the implant from sinking into the craniotomy defect. The tabs are designed so as to contain apertures that allows screws to be directly placed to secure the implant in a secondary procedure to the skull. The fourth component are the screws that are used to fix the implant to the skull. The template and implant are standardised into a kit. The kit is shaped to fit to the right, left or bifrontal aspects of the skull. Thus there are three basic types of kit. The kit can be further defined by a variety of sizes. The most common sizes being small and large.

Description

1 Description The following invention describes the technique and devices required to perform template cranioplasty surgery. The technique requires the surgeon to place a thin pre fabricated cranial prosthetic implant over a craniotomy defect. The implant can float between the patients skin and skull to allow intracranial compliance if brain swelling occurs after surgery. Once brain swelling subsides the implant comes into approximation to the skull. A second stage procedure can then be performed to fix the implant to the skull Step 1 At the time of craniotomy a template is applied to the skull. The outline of the craniotomy is traced on the skull using marking pen, score or diathermy. Step 2 A preformed malleable prosthetic implant is shaped to the skull using pressure and radial force to mould the implant to the contour of the skull. Step 3 The craniotomy is performed using standard technique. Step 4 The preformed malleable prosthetic implant (with a degree of overlap) and multiple fixation tabs is then placed over the craniotomy defect. One tab may be used to fix the implant to the skull with suture or a screw. Step 5 The wound is closed Step 6 As the implant is not securely fixed to the skull if the brain were to swell the implant can allow compliance. As the implant is of significantly less volume than the bone flap that has been removed a greater volume of space will be available to facilitate compliance. Step 7 Once the brain swelling subsides the implant may then be fixed by screws via small stab incisions The invention consists of four separate components. Firstly a template that approximates the skull. Secondly a marking device that can be used to mark around the edge of the template. Thirdly a preformed malleable implant. The implant is manufactured to be thin so that it will have substantially less volume than the bone it replaced. The material is such that it is preformed but can be shaped to a final form intra-operatively by applying pressure and radial force to the implant as it is held in approximation over the skull. The implant is shaped so that it contains tabs that overlap the skull so as to prevent the implant from sinking into the craniotomy defect.

2 The tabs are designed so as to contain apertures that allows screws to be directly placed to secure the implant in a secondary procedure to the skull. The fourth component are the screws that are used to fix the implant to the skull. The template and implant are standardised into a kit. The kit is shaped to fit to the right, left or bifrontal aspects of the skull. Thus there are three basic types of kit. The kit can be further defined by a variety of sizes. The most common sizes being small and large.