Table 2.

Characteristics of biomaterials

Materials	Advantages	Disadvantages	Application
Stainless steel	Very strong	Corrosion	Scoliosis correction (rods)
	Very stiff	Relatively poor biocompatibility	Formerly used in screws; now mostly replaced by titanium
	Easily doped/alloyed to be stronger	High artifacts in imaging
	Inexpensive
Titanium	Lightweight	Relatively Expensive	Screws
	Strong	Some artifacts during imaging	Rods
	Flexible		Plates
	Biocompatible		Cages
	Easily doped/alloyed to be stronger
PEEK	Lightweight	Low Young’s modulus	Rods
	Flexible	Some grafting issues, but improved with coatings	Cages
	Relatively Inexpensive		Disc replacement
	Biocompatible
	Easily doped/coated for improved grafting
	Low artifacts on imaging
CoCr	Strong	Relatively expensive	Adolescent scoliosis correction (rods) to provide a more flexible buttress for the spine to curve about.
	Flexible	High artifacts on imaging
	Biocompatible
Ceramic	Relatively inexpensive	Brittle	Used in cage biomaterials
	Biocompatible	Grafting issues, but can be improved with coating/doping	Doped with A/W
	Ware resistant
	Easily doped
Nitinol	Strong	Relatively expensive	Not frequently used, but can be implemented for young scoliosis correctional surgery.
	“Memory metal” (shape recovery)	Sometimes not stiff enough for proper correction
Tantalum	High frictional characteristics	Very expensive	Not frequently used due to its price.
	Low Young’s modulus	Not stuff enough for some spinal corrections.	Has primarily been phased out completely by titanium.

PEEK, polyetheretherketone; CoCr, cobalt-chromium alloys; A/W, Apatite-Wollastonite.