Lecture 6: Suture Materials & Patterns (Exam 1) Flashcards
What are suture’s important role in wound repair
- Provides hemostasis
- Supports healing tissue by apposing & supporting tissue layers
What determines the type of suture needed
- Type of tissue
- Anticipated duration of healing
What can cause delaying healing of wounds
- Infection
- Obesity
- Malnutrition
- Neoplasia
- Drugs
- Collagen disorders
- Hypoproteinemia
- Radiation therapy
What is the function of suture
Maintain apposition of tissue until wound’s tissue strength returns
Describe the ideal suture
- Easy to handle
- Reacts minimally in tissue
- Inhibits bacterial growth
- Holds securely when knotted
- Resists shrinking in tissue
- Absorbs w/ minimal reaction after the tissue has healed
- Noncapillary
- Nonallergenic
- Noncarcinogenic
- Nonferromagnetic
T/F: The ideal suture material does exist
False: It doesn’t exist
What is the commonly used standard for suture size
United States Pharmacopeia (USP)
Describe USP
- Denotes dimensions from fine to coarse
- According to a numeric scale
What is the smallest suture size
12-0
What is the largest suture size
7
How is “0” read
Ought
What should the smallest diameter suture (that will adequately secure wounded) be used for
- Minimaize trauma as the suture is passed through the tissue
- Reduce the amount of foreign material left in the wound
Is there an advantage to using a suture that is stronger than the tissue being sutured
No
What determines the flexibility of a suture
Its torsional stiffness & diameter
What influences sutures handling & use
Its torsional stiffnes & diameter
What are flexible sutures used for
Ligating vessels or performing continuous suture patterns
What cannot be used to ligate small bleeders
Less flexible sutures like wire
What is considered stiff compared to silk suture
- Nylon
- Surgical gut
What type of stiffness does braided polyester have
Intermediate
What do the surface characteristics of a suture influence
- The ease w/ which it is pulled through tissue (the amount of friction of “drag”)
- The amount of trauma caused
(Rough/smooth) sutures causes more injury
Rough
(Rough/Smooth) are particularly important in the delicate tissues like the eye
Smooth
What are the cons of sutures w/ smooth surfaces
- Require greater tension to ensure good apposition of tissues
- have less knot security
Which material has more drag than monofilament sutures
Braided materials
Why are braided materials often coated
- Reduce capillarity
- Provides a smooth surface
What are braided materials usually coated w/
- Teflon
- Silicone
- Wax
- Paraffin wax
- Calcium stearate
What is capillarity
- The process by which fluid & bacteria are carried into the interstices of multifilament fibers
- Neutrophils & macrophages are too large to enter interstices of the fiber (infection can persist particularly in nonabsorbable sutures)
- Braided materials have degrees of capillarity
What suture is considered noncapillary
Monofilament
What reduces the capillarity of some sutures
Coating
Where should capillary suture materials not be used
In contaminated or infected sites
What is knot tensile strength
- Measured by the force in pounds that the suture strand can withstand before it breaks when knotted
- Sutures should be as strong as the norm tissue through which they are being placed
- Tensile strength should not greatly exceed the tensile strength of the tissue
Define relative knot security
The holding capacity of a suture expressed as a % of its tensile strength
Define knot holding capacity
The strenth required to untie or break a defined knot by loading the part of the suture that forms the loop
Define tensile strength
The strength required to break an untied fiber with a force applied in the direction of its length
Describe monofilament suture
- A single strand of material
- Less tissue drag than multi
- Do not have interstices that can harbor bacteria or fluid
Why should care be used in handling monofilament suture
B/c nicking or damaging the material w/ forceps or needle holders may weaken the suture & predispose it to breakage
Describe multifilament suture
- Consist of several strands of suture that are twisted or braided together
- More pliable & flexible than mono
- May be coated to reduce tissue drag & enhance handling characteristics
Compare mono to multi filament
- Mono: nonwicking, more memory, & does not handle as well
- Multi: wicking, less memory, & good handling
What are the two major mechanisms of absorption that results in the degradation of absorbable sutures
- Sutures of organic origin are gradually digested by tissue enzymes & phagocytized
- Sutures manufactured from synthetic polymers are principally broken down by hydrolysis
How are nonabsorbable sutures handled by the body
Encapsulated or walled off by fibrous tissue
List some absorbable suture materials
- Surgical gut
- Chromic gut
- Multifilament
Describe absorbable suture materials
- Lose most of their tensile strength w/in 60 days
- Eventually disappear from the tissue implantation site b/c they have been phagocytized or hydrolyzed
- The time to loss of strength & for complete absorption varies among suture materials
Describe Catgut (surgical gut)
- Most common nonsynthetic absorbable suture material
- Made from the submucosa of sheep intestine or the serosa of bovine intestine
- ~90% collagen
- Broken down by phagocytosis
- Elicits a notable inflammatory reaction
- Loses strength rapidly after tissue implantatioon
- “Tanning” slows absorption
- Rapidly removed from infected sites or areas where it is exposed to digestive enzymes & is quickly degraded in catabolic px
- Knots may loosen when wet
Describe synthetic absorbable suture
- Broken down by hydrolysis
- Causes minimal tissue reaction
- Time to loss of strength & to absorption is fairly constant even in different tissue
- Infection or exposure to digestive enzymes does not significantly influence the rate of absorption of most synthetic absorbable sutures
- Polyglycolic acid, polyglactin 910, & poliglecaprone 25 may be rapidly degraded in infected urine
What are the types of nonabsorbable suture
- Organic
- Synthetic
- Metallic
Describe Organic nonabsorbable suture
- Silk is the most common organic nonabsorbable suture
- Braided multifilament suture made by a special type of silkwork
- Can be coated or uncoated
- Excellent handling characteristics
- Often used in cardiovascular procedures
- Should be avoided in contaminated sites
Describe synthetic nonabsorbable suture
- Braided multifilament threads or monofiliament threads
- Typically strong & induce minimal tissue reaction
Can table ties be implanted in the body, & why not
- Never
- Release of toxic substances during their degradation & their use may result in abscess or tumore formation
Describe metallic sutures
- Stainless stell is most commonly used
- Monofilament or multifilament twisted wire
- Surgical steel is strong & inert w/ minimal tissue reaction
- Knot ends evoke an inflammatory reaction
- Tendency to cut tissue
- May fragment & migrate
Describe surgical steel
- Is stable in contaminated wounds
- Standard for judging knot security
- Standard for judging tissue reaction to suture materials
What should be considered for suture selection
- Length of time the suture will be required to help strengthen the wound or tissue
- Risk of infection
- Effect of the suture material on wound healing
- Dimension & strength of the suture required
What suture should be used in the skin
- Monofilament to prevent wicking or capillary transport of bacteria to deeper tissue
- Synthetic monofilament nonabsorbable generally have good relative knot security & are relatively non-capillary
- Absorbable sutures may be used in the skin but they should be removed b/c absorption requires contact w/ body fluids
What suture should be selected for SubQ tissue
- SubQ sutures are used to obliterate dead space & reduce tension on skin edges
- Multi- or monofilament absorbable suture material is preferred
What suture should be selected for abdominal closure
- Can be closed w/ either an interrupted or continuous suture pattern
- Most surgeons routinely close the rectus fascia w/ a simple contnuous suture pattern
- Continuous suture pattern = strong nonabsorbable or standard absorbable monofilament suture w/ good knot security should be used
- one size larger suture than normal is preferred for a continuous suture pattern
- Knots should be tied carefully & three or four square knows (six or eight throws) should be placed
- Standard absorbable suture may be preferable to prevent large amounts of foreign material from remaining permanetly in the incision
What suture should be selected for muscle
- Muscle has poor holding power & is difficult to suture
- Can be absorbable or nonabsorbable
- Sutures placed parallel to the muscle fibers are likely to pull out so consideration should be given to the type of suture pattern chosen
What suture should be used for the tendon
- Needs to be strong, nonabsorbable, & minimally reactive
- A taper or taper-cut needle generally is less traumatic to these tissues
- Largest suture that will pass w/out trauma through the tendon should be used
Which suture should be used for parenchymal organs
- Absorbable monofilament suture
- Multifilament sutures tend to cut through this type of tissue b/c of the increased drag
What suture should be used for hollow viscus organs
- Absorbable monofilament sutures generally are recommended to prevent tissue retention of foreign material once the wound is healed
- Nonabsorbable may be calculogenic when place in the urinary bladder or gallblader & may be extruded into the lumen when implanted in the intestine
- Polyglycolic acid (Dexon) suture rapidly dissolves when incubated in sterile urine (6 days) or infected urine (3 days)
What suture should be selected for infected or contaminated wounds
- Sutures should be aboided in highly contaminated or infected wounds
- Multifilament nonabsorbable sutures should not be used in infected tissue
- Absorbable suture is preferred
- Surgical gut should be avoided
- Synthetic monofilament nylon & polypropylene may elicit less infection in contaminated tissue than metallic sutures
What sutures should be selected for vessels & vascular anastomoses
- Ligated w/ absorbable suture material
- Vascular anastomoses are typically performed w/ monofilament nonabsorbable suture material like polypropylene
What does selecting a surgical needle depend on
- Type of tissue to be sutured
- Topography of the wound
- Characteristics of the needle
Why are most surgical needles made from stainless steel
- Strong
- Corrosion free
- Does not harbor bacteria
Define surgical yield
The amount of angular deformation a needle can withstand before becoming permaneltly deformed
Define ductility
The needle’s resistance to breaking under a specified amount of bending
Define sharpness
The angle of the point & the taper ratio of the needle
What do the sharpest needles have
A long thin tapered point w/ smooth cutting edges
Describe the basic components of a needle, types of eyed needles, & the shapes/sizes of needle bodies
What is considered when selecting a curved needle
- The depth & diameter of a wound are impt when select the most appropriate curved needl
- 1/4 circle needles are primarily used in opthalmic procedures
- 3/8 & 1/2 circle needles are the most commonly used surgical needles in vet
- 1/2 or 5/8 circle need is easier to use in confined locations despite needing more pronation & supination of the wrist
How can suture patterns be classified
- Interrupeted
- Continuous
- Appositional
- Everting
- Inverting
- SubQ
- Subcuticular/intradermal
Define appositional
One tissue edge apposed to another
Define everting
Turn the tissue edges outward awfrom the px & toward the surgeon
Define Inverting
Turn tissue away from the surgeon or toward the lumen of a hollow viscus organ
Elaborate on SubQ sutures
- Eliminate dead space
- Provide some apposition of skin so that less tension is placed on skin sutures
- Generally placed in a simple contnuous manner (simple interrupted may be preferable if drainage might be needed)
Elaborate on subcuticular sutures
- Suture line is completed w/ a buried knot
- No sutures are visible externally when complete
- Absorbable suture materials w/ a cutting needle are preferred for this suture pattern
Which is Suctuicular & which is SubQ
- A = Subcuticular
- B = SubQ
List interrupted suture patterns
- Simple interrupted
- Horizontal mattress
- Cruciate
- Vertical mattress
- Halstead
- Gambee
Describe simple interrupted
- Made by inserting the needle through tissue on one side of an incision or wound, passint it to the opposite side, & then tying it
- The knot is offset so that it does no rest on top of the incision
- Ends of the suture are cut
- For skin sutures the ends are left long enough to allow them to be grasped during removal
- Sutures are placed approx 2 to 3 mm away from the skin edge
- Right handed surgeons place sutures from right to left in a horizontal fashion (opp for left handed surgeons)
What is the primary advantage of simple interrupted sutures
Disruption of a single suture doesn’t cause the entire suture line to fail
Do simple continuous or simple interrupted sutures take more time
Simple interrupted
Which suture pattern results in more foreign material in the wound
Simple interrupted
Describe horizontal mattress pattern
- Used primarily in areas of tension
- Placed rapidly
- Often cause tissue eversion (care should be exercised to appose, rather than evert, tissue margins)
- Suture should be angled through the tissue so that it passes just below the dermis
- separated 4 to 5 mm
- Can be bolstered using rubber stents & buttons
Describe the cruciate suture pattern
- Formed when two simple interrupted sutures are placed parallel to each other & then tied across the incision to create and “X”
- Appositional
- Can relieve low to moderate tension across an incision
- Less suture material is used to close a skin incision than w/ simple interrupted
- Affords the security of an interrupted pattern
Which is simple interrupted, horizontal mattress, & cruciate
- A = Simple interrupted
- B = Horizontal mattress
- C = Cruciate
Describe the vertical mattress pattern
- Stronger than horizontal mattress sutures
- Preferred when addressing tension in skin closure
- Less disruption to the blood supply of the wound edges
- Each bite approx 4 mm from the skin edge
- Rel time consumin
- Eversion of the skin margins is less of a prob
- Can be bolstered using rubber stens & buttons
Define stents
Placing padded material beneath the suture loops is stenting
Describe the halstead suture pattern
- An interrupted mattress pattern that is a modification of a cont lembert pattern
- Infrequently used in vet med
- Provides exact skin approx
Describe the Gambee suture pattern
- Interrupted pattern used in intestinal surgery to reduce mucosal eversion
- Also reduces mucosal inversion & may reduce wicking of material from the intestinal lumen to the exterior
Which is the vertical mattress, halsted, & Gambee
- D = vertical mattress
- E = Halsted
- F = Gambee
List the continuous suture patterns
- Simple continuous
- Running
- Ford interlocking
- Lembert
- Connel
- Cushing
Describe the simple continuous pattern
- Consists of a series of simple interrupted sutures w/ a knot on either end
- Provides max tissue apposition
- Relatively air & fluid tight compared w/ a series of simple interrupted sutures
- Freq used to close the linea alba & SubQ tissue
- Care should be taken when placing continuous suture lines in areas where tightening of the suture may result in a purse string like effect
What is the difference btw/ simple continuous & running suture patterns
- Simple continuous: The needle is then passed through the tissue from one side to the other, perpendicular to the incision; the suture is advanced above the incision line @ a diagonal
- Running: Created if the suture is advanced above & below the incision line but this is not as secure as less tissue is purchased; not as secure since there is less tissue is purchased
Which is the running and which is the simple continuous suture pattern
- Blue = Running
- Black = Simple continuous
Describe the ford interlocking pattern
- Modification of a simple continuous
- Each passage through the tissue is partly locked
- Each pass through the tissue is linked to the previous passage as the suture exits the tissue through a created loop of material
- May be placed quickly
- May appose tissue better than a simple interrupted pattern
- Provides greater stability than a simple continuous pattern in the event of a partial break along the line
- Larger amount of suture material is used
- Sutures may be more difficult to remove
Which suture pattern is this
Ford interlocking
Describe the Lembert suture pattern
- A variation of a vertical mattress pattern applied in a continuous fashion
- Is an inverting pattern that is often used to close hollow viscera
Describe cushing & connell suture pattern
- Inverting patterns that are used to close hollow organs
- Watertight seal is created by inversion
Whats the differnce btw/ the cushing & connell pattern
- A connell pattern enters the lumen whereas a cushing pattern extends only to the submucosal layer
- It was prev though that a cushing pattern would be preferable to a connell for cystotomy closure b/c suture material in the lumen might be calculogenic; however the use of rapidly absorbed monofilament sutures negates this concern
Which is Lembert, Connell, & Cushing
- D = Lembert
- E = Connell
- F = Cushing
Describe the parker-kerr oversew
- A two layer closure for inverted closure of a transected,clamped, stump of hollow viscera
- Begins w/ cushing/connell, followed by an inverting seromuscular pattern
- Seldomly used b/c it causes excessive tissue inversion
What suture configurations are used to approximate severed ends of a tendon or to secure one end of a tendon to bone or muscle
- Kessler locking loop
- Bennel Mayer
- Krackrow
- Three loop pulley
Label these suture patterns
- A = Far-near near-far
- B = Bunnell-Mayer technique
- C = Three loop pulley
- D = locking loop
