the application of 316l stainless steel in stapedotomy surgical procedure

8/12/2019 The Application of 316l Stainless Steel in Stapedotomy Surgical Procedure

1/27

THE APPLICATION OF 316LSTAINLESS STEEL IN

STAPEDOTOMY SURGICAL

PROCEDURE

PRESENTED BY:

AFIZA BT AHMAD FAIRUZI

NEK NORSUHAILAH BT AMINON

NUR LIYANA BT MAT AZAM

NURUL NAQIAH BT KHAIFULLIZAN


2/27

Contents


3/27


4/27

Normal hearing mechanism


5/27

Normal hearing mechanism


6/27

Otosclerosis

In otosclerosis, the final hearing bonein the chain is the stapes (stirrup)become fixed so that little or no movement is possible. This causes a

block in the transmission of the sound waves and deafness results.


7/27

Application


8/27


9/27


10/27


11/27


12/27


13/27


14/27


15/27


16/27


17/27

In the austenitic stainless steels the atoms,here

iron, chromium and nickel, are arranged on thecorners of the cube and in the center of each ofthe faces of the cube.


18/27

Grade TensileStrength

(Mpa) min

YieldStrength

0.2% Proof(Mpa) min

Elongation(% in 50

mm) min

Hardness

Rockwell B(HR B) max

Brinell(HB) max

316 515 205 40 95 217

316 L 485 170 40 95 217

316 H 515 205 40 95 217


19/27

Mechanical properties of metal are thebehavior of metals that measured under the

effect of external forces.


20/27

Tension test is the most common method todetermine the mechanical properties of materials,such as strength, ductility, toughness, elasticmodulus, and strain hardening capability.

Another important mechanical property of metal isthe hardness which gives a general indication of itsresistance to localize plastic deformation.

Beside composition, metallurgical state and synthesisprocess of the metals change their mechanicalproperties, i.e. annealed condition has better ductilitythan that of cold worked and cast metal implantsusually possess lower strength than those made byforging.


21/27

Different from the breakdown in the tension testwhere the specimen is subjected under gradualincrease of loading until fractures, failure of acomponent practically occurs after a lengthy period

of repeated stress or strain cycling. This phenomenon is called fatigue failure and

responsible for the majority of failures in manymechanical components. To avoid this kind of

failure, the stress level should be reduced to a levelwhich the material can be subjected without fatiguefailure, regardless of the number of cycle. Themaximum level of loading stress is known as the

endurance limit or fatigue limit.


22/27

Grade 316 is the standard molybdenum-bearing grade, secondin importance to 304 amongst the austenitic stainless steels.The molybdenum gives 316 better overall corrosion resistant

properties than Grade 304, particularly higher resistance topitting and crevice corrosion in chloride environments.

Grade 316L, the low carbon version of 316, is immune fromsensitization (grain boundary carbide precipitation). Thus it isextensively used in heavy gauge welded components (overabout 6mm). There is commonly no appreciable pricedifference between 316 and 316L stainless steel.

The austenitic structure also gives these grades excellent

toughness, even down to cryogenic temperatures (productionof very low temperature, how to produce and how materials

behave at those temperature).


23/27

Compared to chromium-nickel austenitic stainless

steels, 316L stainless steel offers higher creep, stress

to rupture and tensile strength at elevatedtemperatures.

Endura Met(R) 316LN stainless is a nitrogen-

strengthened version of Type 316L stainless. By

means of solid solution strengthening, the nitrogen

provides significantly higher yield and tensile

strength as annealed than Type 316L without

adversely affecting ductility, corrosion resistance ornon-magnetic properties. In the hot rolled unannealed

condition, yield strength of 75 ksi (518 MPa) or

higher can be achieved for bar diameters up to

1.375in (34.925mm).


24/27

It appears that Type 316 is a standard stainless steel,316L is a low carbon stainless steel, and 316LN is alow carbon nitrogen strengthened stainless steel.

Basic mechanical strength increases with alloy

additions, but the atomic structure differences of thevarious groups of stainless steels has a moreimportant effect.

Only the martensitic stainless steels are hardenable

by heat treatment, like other alloy steels.Precipitation hardening stainless steels arestrengthened by heat treatment, but use a differentmechanism to the martensitic types.


25/27

In stapes prosthesis, biocompatibility involvesthe acceptance of an artificial implant by thesurrounding tissues and by the body as a whole.The implants do not irritate the surrounding

structures, do not incite an excessiveinflammatory response, do not stimulateallergic and immunologic reactions, and do notcause cancer.

The main demands on a stapes prosthesis aregood bio-tolerance, simple intraoperativehandling and good sound transmission


26/27

The ability of its piston wire to self-fasten or crimpsecurely around the incus following the application ofheat. This self-crimping property is reported to

provide a more secure fit between the wire and theincus which in turn leads to improved transmission ofsound. By eliminating manual crimping and reducingthe manipulation of the prosthesis in the middle ear,the prosthesis should theoretically lower failure rates.

The selection of a particular prosthesis by individualsurgeons is dictated by the ease of usage, safety andfavourable hearing outcomes.


27/27

CONCLUSION

In general the operation is very successful withover 90% of people experiencing a goodimprovement in hearing.

However, sometimes the hearing remainsunchanged and there is a small (approx 1-2%)chance of hearing loss.

Eventually, this implant offer an option forpeople that may facing permanent hearing lossto fix their problem.

the application of 316l stainless steel in stapedotomy surgical procedure

Documents