Surgical materials Flashcards
What 4 things do we want of the suture material in terms of the body?
- non-electrolytic (not metal)
- non-capillary (a downfall of monofilament)
- non-allergic
- non-carcinogenic
What are 6 things that the surgeon will want from the suture material?
- Easy to use
- Minimal tissue ‘drag’
- Good knot security
- Inexpensive
- Easily available
- Easy to sterilise without alteration
What is tensile strength?
The breaking strength per unit area.
What is memory?
The tendency to retain original configuration.
What is ‘chatter’ and tissue ‘drag’?
Lack the smoothness when passing through tissue.
Tissue reaction?
This is when the body responds to the presence of suture material like they would other foreign bodies and there is an inflammatory response.
Name two reasons multifilament is more prone to infection than monofilament?
Multifilament has a greater surface area and more access to the body.
The body finds it hard to access some areas of multifiliament compared to monofilament.
Which cause more reaction, natural materials or man-made materials?
Natural materials - man-made materials have been designed with minimal reaction.
What are the three parts to the needle?
- the point
- the body
- the eye
A needle’s radius of curvature is expressed in what?
The proportion of the circle
Which two types of needle will we most commonly be using?
3/8ths or 1/2 circle
What are straight and curved needles handled with?
Straight needles are handled manually whereas curved needles are held with needle holders.
What are the three types of needle cutting points?
- Blunt (circular, elliptic)
- Sharp (Polygonal)
- Compound (tapercut)
How big is the tapercut point in comparison with the rest of the body?
It will never be wider than the rest of the body.
Do we mostly use standard cut or the reverse cut?
We mostly use the reverse cut.
What two types of needle can you get?
Eyed or swaged
Name three different types of eye?
- Closed
- Open
- Split
Name 3 disadvantages of using eyed needles?
- Double width of suture material
- Multiple use leads to blunting
- increased tissue trauma
Name three benefits of swaged needles?
- minimal trauma
- Single-use
- Optimal penetration properties
What are needles made out of?
Stainless alloys
What is ‘Ductility’?
This is when the needle bends before breaking and tells the surgeon that the force being placed on them is too great.
What is the curve of the needle proportional to?
The wound depth or the difficulty of access.
Which two needles should you use wherever possible?
Blunt or compound.
When should you use triangular needles?
For very resistant material
What three things would be considered about the wound when selecting a suture material?
- tensile strength
- bacterial charge
- current of planned therapies
To support wound healing and prevent infection, what 5 things would you need to do with your suturing?
- Limit dead space
- As little suture material as possible in the wound
- Chose a biologically inert suture material
- Minimise tissue trauma
- Limit ischaemia - leave enough space between each bit and tighten without excess.
How to determine if absorbable or non-absorbable?
If unchanged after 60 days, non-absorbable.
What is elasticity?
This is when you stretch the material, how well it returns to its original shape.
What is plasticity?
This is how well the material loses its original shape when stretched.
What three things does the suture composition determine?
- tensile strength
- Biologic behaviour
- Handling
Name three examples of natural material?
- catgut
- silk
- surgical steel
Name 3 benefits of monofilament?
- Has smooth surface that allows easy passage through tissues
- Reduced bacterial growth
- Reduced capillary action
What is a disadvantage of monofilament?
- High memory which can make handling difficult
2. Stiff ends can cause irritation if they are not buried.
Name 3 diasadvantages of multifilament?
- Rough surface which increases tissue drag
- Gaps between the filaments act as a nidus for infection
- Capillary action/ wicking
Name 2 advantages of multifilament?
- easy to handle
2. soft and pliable and well tolerated by patients.
What is wicking?
This is when moisture is drawn away from the body - capillary action.
name a commonly used monofilament?
Vicryl.
What is USP?
United States Pharmacopia - diameter/size of suture material
What is USP based on?
Tensile strength rather than diameter.
What is the range for USP?
11-0 –> 7 (11-0 is the smallest and 7 is the biggest)
What is the other scale for measuring diameter of suture material and how is it graded?
Metric EP.
1/10mm e.g. ‘2’ = 0.2mm
What is the range of the metric EP scale?
0.1-10
Originally, what was the scale of suture diameter?
1-6 with 1 being the smallest.
What does knot security relate to?
The surface frictional characteristics of the material (monofilament vs multifilament)
What type of material will require more knot throws?
Material with higher memory
What is required for knot security of biosyn?
2x1x1x1
What is required for knot security of polysorb?
2x1x1
What is required for knot security of biosyn?
2x1x1x1
How many throws for square knot? what happens if more than this?
1 throw only, more will convert to slip knot - this is dangerous
How many throws for a granny knot?
1x1
How many throws on a surgeons knot square?
2=1
When would you use a surgeons knot?
Only when required e.g. if the wound was under lateral tension.
What are the 4 interrupted skin patterns for closure?
- Simple interrupted
- Cruciate mattress
- Vertical mattress
- Horizontal mattress
Name 6 types of continuous suture patterns?
- Simple continuous
- Subcuticular
- Ford interlocking
- Cushing
- Connel
- Lambert
What is the difference between cushing and connel?
The connel penetrates all layers of the wall with each needle bite however the cushing only penetrates the serosa, passing through muscularis only for 5 mm.
What is Lembert designed to do?
Invert the edges of the wound/
What would you use Lembert?
Bowel surgery or following casarean in the uterus.
What are the 4 main reasons for suture dehiscence?
- Knot slippage
- knot breakage
- Tissue laceration
- Weakening of the knot during handling, crushing and shearing etc
If you do what to the material, it is more likely to break down?
Crush the material.
What are the pros and cons or staples?
They are not very cheap, are painful and irritating.
They are however quick e.g. if you have a big wound and you want the animal out of theatre quickly, or if a wound keeps opening up.