By: Ryan Pyrke and Anuja Goyal

Transcription

1 By: Ryan Pyrke and Anuja Goyal

2 Phineas Gage ( ) A 1 meter long tamping iron which weighed 6 kilograms impaled Phineas skull Miraculously survived. One of the most famous and earliest recorded survivors of a severe skull fracture 2

3 Overview Anatomy of the skull Types of skull and maxillofacial trauma Methods of treatment Future research 3

4 Anatomy of the Skull 4

5 Types of Trauma Basilar skull fracture Penetrating skull fracture Depressed and Compound skull fracture Linear and Diastasis fractures 5

6 Basilar skull fracture 6

7 Penetrating skull fracture 7

8 Depressed skull fracture 8

9 Linear & Diastasis fractures 9

10 Methods Of Treatment Autologous Reconstruction Allogenic Reconstruction Alloplastic Reconstruction Titanium Plates and Screws Titanium Mesh Ceramics (Glass) Calcium Orthophosphate Polymethyl-methacrylate (PMMA) 10

11 Autologous Reconstruction Replacement bone from the patient is used to mend a fracture Bone chips or dust can be used to mend small holes High degree of biocompatibility and long term stability 11

12 Autologous Reconstruction (cont) Complications can arise at the donor sites of the patient Not a suitable method for large skull fractures 12

13 Allogenic Reconstruction Bones from donors (living or cadaveric) are used to mend a skull fracture Live donors share the same problems as autologous reconstruction Short supply of materials Xenografts may be possible in the near future that use bovine materials 13

14 Alloplastic Reconstruction Synthetic substitutes are used in place of live materials Materials used to create these implants include titanium, ceramics, calcium orthophosphate, PMMA, and others Each have their own individual benefits and drawbacks 14

15 Titanium Plates and Screws A very strong material. Biocompatibility has been proven over a long period of time Most commonly used material for the skull. Easy to implant and inert within the body Alloys of titanium come very close to matching mechanical properties of bone 15

16 Titanium Plate Example Osteoplastic craniotomy perfomed to alleviate pressure on the brain Can be performed to provide access to brain (i.e. to remove tumors) 16

17 Titanium Mesh Allows for natural bone growth in the gaps of the titanium mesh. Over time becomes very strong and stable. Risk of infection with larger scale bone replacement. 17

18 Ceramics (Glass) Very bio-compatible Post-operative imaging is unhindered Easy to break when fixing it to the skull TiO2 /glass composites are used Fibrous tissue will not form around this material Small implants can be connected by chemical bonding 18

19 Calcium Orthophosphate Very poor mechanical properties Biocompatible and nontoxic Osteointegrates into living tissue Acts as an osteoconductive scaffold for new bone Used as a coating to promote bone growth into porous implants 19

20 Calcium Orthophosphate Used only as fillers, coating, or bone cement and not practical for large-scale skull reconstruction Protect against emission of toxins from a coated material Increases the lifetime of an implant it is integrated into 20

21 Polymethyl-methacrylate (PMMA) PMMA is used most often for cranial reconstruction Powder Polymer and Liquid Monomer combine to form cement that then hardens. Heats up to 70 C when mixed raising a concern for surrounding tissue Performed free-hand 21

22 Future Applications Biodegradable Plates Ion Implantation Biodegradable Adhesives 22

23 Biodegradable Plates Plates and screws that will be reabsorbed over time Biocompatible Adaptable Degrades at right amount of time Stable enough to allow bone to unify 70/30 poly(l/dl-lactide) (PLDLA) is a biodegradable material 23

24 Biodegradable Plates (continued) 24

25 Biodegradable Plates (continued) Advantages: Plate and screws would not need to be removed later on Since the material is reabsorbed it will not affect long term development in children 25

26 Biodegradable Plates (continued) Future Steps: Develop material for larger plate applications Investigate long-term effects of resorption Make material easier to work with 26

27 Ion Implantation Process used to make materials more bio-compatible Prevents production/leakage of toxic byproducts Ions are embedded on outer layer 27

28 Ion Implantation 28

29 Biodegradable Adhesives An adhesive to hold bones together while degrading over time Development considerations Must bond to bone in a wet, bloody environment Cannot be cytotoxic Strong enough to hold bone together Disappear gradually 29

30 Biodegradable Adhesives Biomimicry: solving problems using examples from nature Proteinaceous Adhesive produced by Sandcastle Worm Used to assemble bits of seashells underwater Composed of opposite charged proteins with Ca 2+ /Mg 2+ ions Developed biodegradable adhesive Used to repair crainiofacial fractures Created with oppositely charged copolyelectrolytes 30

31 Biodegradable Adhesives It is a phase separated fluid Will not cause volume change Non-cytotoxic Tested both in vitro and in vivo in a rat 31

32 Progression Of Surgical Methods Implantation Of A Titanium Plate Current Surgical Procedure CAD Technology 32

33 Implantation Of A Titanium Plate during initial surgery: first clean up wound template is made from soft malleable metal skull thickness is measured preparation of plate: dental plaster cast made from impression titanium plate is formed by using a high pressure hydraulic pump Many holes on the plate allow fluid to flow and fibrous tissues to go through Insertion of Plate: A second surgery is performed to insert the plate 33

34 Current Surgical Procedure Technology is used to create custom skull implants 34

35 CAD Technology 35

36 Ongoing Development Various companies and institutes are actively researching maxillofacial and skull implants Kelyniam is able to provide custom skull implants 24 hours after receiving CT scan data Research centered around the use of PEEK, a growingly popular new biomaterial 36

37 References 1. T. R. Rautray, R. Narayanan, and K. Kim. Ion Implantation of Titanium Based Biomaterials Progress in Materials Science, vol. 56, pp , Deakin University Australia. Phineas Gage s Story. Internet: [September 19, 2011]. 3. Kelyniam. Kelyniam Announces Commercial shipping of Custom Skull Implants Internet: August 2, 2011 [September 18, 2011]. 4. Heraeus. Heraeus Medical Internet: [September 20, 2011]. 5. Synthes, CMF Craniofacial Reconstruction Internet: Pages/home.aspx, 2010 [September 21, 2011]. 6. Stryker, Stryker Navigation system II Internet: [September 20, 2011]. 7. R. L. Drake, W. Vogl and A. W. M. Mitchell. Head and Neck in Gray s Anatomy for Students, B. Smith, Ed. Philadelphia: Elsevier, 2005, pp S. Monkhouse. Regional Anatomy in Clinical Anatomy, 2 nd ed.,t. Horne, Ed. London: Elsevier, 2007, pp

38 References 9. S. V. Dorozhkin. Bioceramics of Calcium Orthophosphates Biomaterials, vol. 31, pp , Dec B. R. Bell and C. S. Kindsfater. The Use of Biodegradable Plates and Screws to Stabilize Facial Fractures Journal of Oral and Maxillofacial Surgeons, vol. 64, pp , B. D. Winslow, H. Shao, R. J. Stewart, and P. A. Tresco. Biocompatibility of Adhesive Complex Coacervates modeled After the Sandcastle glue of Phragmatopoma Californica for Craniofacial Reconstruction Biomaterials, vol. 31, pp , Oct W. Wu, Y. Zhang, H. Li, and W. Wang. Fabrication of Repairing Skull Bone Defects Based on the Rapid Prototyping Journal of Bioactive and Compatible Polymers, vol. 24. pp , May D.S. Gordon and G. A. S. Blair. Titanium Cranioplasty British Medical Journal, vol. 2, pp , U. Spetzger, V. Vougioukas, and J. Schipper. Materials and Techniques for Osseous Skull Reconstruction Minimally Invasive Therapy, vol. 19, pp , U. Klammert, U. Gbureck, E. Vorndran, et al. 3D Powder Printed Calcium Phosphate Implants for Reconstruction of Cranial and Maxillofacial Defects Journal of Cranio- Maxillo-Facial surgery, vol. 38, pp , M. geetha, A.K. Singh, R. Asokamani, and A.K. Gogia. Ti based Biomaterials, the ultimate choice for orthopaedic implants A review Progress in Materials Science, vol. 54, pp , B Braun, Partner for Surgery Internet: [September 20, 2011]. 38