2. Definitions
Tensile strength (TS) = the force, in pound, which the suture strand can withstand before it breaks when knotted.
Breaking strength retention (BSR) = measures tensile strength retained by suture in vivo over time. Example – a suture with an initial TS of 20 lb & 50% of its BSR at 1 week, has 10 lb of TS in vivo at 1 week.
Twisted = having one part or end turned in the opposite direction to the other
Braided = interwoven from three or more strands
Memory = tendency not to lie flat, but to return to given shape set by the material’s extrusion process or the suture’s packaging

3. Types Monofilament / multifilament Absorbable / Non-absorbable
Natural / Synthetic

4. Monofilament Made of a single strand of material Advantages:
- pass easily through the tissue
- tie down easily, but knots are not strong
- smooth surface -do not form a nidus for microorganisms – less suture line infection
- have memory
Disadvantages:
- fine structure – weakened by crushing or crimping – weak points – suture breakage (careful handling)
- less TS than multifilament

5. Multifilament Made of several strands, twisted or braided together.
Advantages:
- more TS, pliable, flexible
- more strong than monofilaments, withstand crimping
- smooth tie down
- precise knot placement
- handle well
Disadvantage:
- pass less easily through the tissues – coated = pass easily & easy handling
- not suitable in infected wound – nidus for microorganism (rough surface) - infection
- dragging & sawing effect

6. Absorbable & Non-absorbable
Absorbable suture = that lose their TS within 60 days.
Non-absorbable = that maintain their TS more than 60 days.
Some AS lose TS > 60days.
Some NAS lose TS < 60 days

7. Absorbable They will be absorbed after a length of time.
They are used to hold wound edges in approximation temporarily, until they have healed sufficiently to withstand normal stress.
May be natural or synthetic:
- natural from collagen of healthy mammals (submucosa of the intestine of the cows, sheep) – absorbed by digestion by body enzymes
- synthetic polymers are absorbed by hydrolysis
Absorption process – 2 stages:
- 1st stage – gradual, almost linear decrease in TS
- 2nd stage – complete absorption of the suture mass

8. The loss of TS & the rate of absorption are separate phenomena – TS may be lost rapidly but absorption takes long time
- TS may be retained for long time, but absorption occurs rapidly
They are colored for easy recognition & visibility
Advantages:
- easy to handle – most are impregnated or coated to improve handling
- when completely absorbed – no foreign body reaction
Disadvantages:
- substantial tissue reaction (more with natural than with synthetic) as both stages of absorption are associated with leukocytic cellular response to remove cellular debris & suture mass

9. - Not suitable in the following situation as absorption is accelerated = TS is decreased = wound complications & breakdown:
- presence of fever, infection, protein deficiency
- use in moist or fluid filled cavity
- if suture becomes wet or moist during handling before implantation

10. Non-absorbable
Made of materials that are not digested by body enzymes or hydrolyzed in body tissue.
Monofilament / multifilament
Metal / synthetic fibers / organic fibers
Twisted / braided
Uncoated / coated
Uncolored / colored – naturally, synthetic dyes

11. USP classification:
Class I: silk or synthetic fibers of monofilament, twisted, or braided construction
Class II: cotton or linen fibers, or coated natural or synthetic fibers where the coating contributes to suture thickness without adding strength
Class III: metal wire of monofilament or multifilament construction
Advantages:
- minimal tissue reaction
- pass easily through tissues
- difficult handling & knotting
- lengthy TS
- weakened by crushing, crimping

12. Natural absorbable sutures

13. Natural absorbable sutures
Surgical gut – plain surgical gut & chromic gut
Made of strands of highly purified collagen
TS is determined by the amount of collagen
Tissue reaction depends on purity of collagen (more pure = less reaction)
Rate of absorption depends on:
- type of gut used
- type & condition of the tissue involved
- general health of the patient
Risk of bovine spongiform encephalopathy

14. Plain surgical gut Material - Beef serosa or sheep submucosa
Monofilament / Yellowish - tan
TS = 7-10 days
Absorption = 70 days
Fast absorbing plain surgical gut – heat-treated for decrease TS & accelerate absorption – used for epidermal suturing where sutures are required for 5-7days

15. Chromic gut Material - Beef serosa or sheep submucosa
Monofilament / Brown / blue dyed
Treated with chromium salt solution to resist body enzymes
TS = days (10-14 days)
Absorption = 90 days
Less tissue irritation than plain gut

16. Indications:
- All surgical procedures, esp. for tissues that regenerate (heal) faster & require minimal support – ligation of superficial blood vessels, suturing s-c tissue
CI: incisions that require the sustaining of the tissues for a prolonged period of time
Precautions: cancer, anemia, malnutrition, infected wounds, mouth, vagina (fast absorption), c-v surgery (continued heart contractions)

17. Advantages of natural absorbable sutures
Very high knot-pull tensile strength Good knot security Excellent handling features
Main disadvantages of natural absorbable sutures:
Antigenicity
Tissue reaction
Unpredictable rates of absorption
Risk of bovine spongiform encephalopathy

18. Synthetic absorbable sutures

19. Polyglactin (Vicryl)
Multifilament, coated/uncoated, braided, dyed violet/undyed
TS - 75% at 14 days
- 50% at 21 days for suture ≥ 6-0
- 40% at 21 days for suture ≤ 7-0
- 25% at 28 days for suture ≥ 6-0
Absorption – minimal at 40 days – complete between days (63 days avg)

20. Vicryl Rapida (Polyglactin)
Braided / Undyed
TS: - 5 days
days
Absorption - 42 days

21. Polyglycolic acid (Dexon)
Multifilament / monofilament, coated, dyed in violet
TS - 70% at 14 days
- 50% at 21 days
- <10% at 28 days
- 0% at days
Complete absorption at 90 days
Effective wound support – 3 weeks

22. Poliglecaprone (Monocryl)
Monofilament, dyed in violet/undyed,
TS Dyed Undyed
7 days % %
14 days % %
28 days (0%) 21 days (0%)
Absorption = days

23. Polydioxanone (PDS II)
Monofilament, violet dyed/undyed
TS 4/0 smaller 3/0 larger
2 weeks 60% %
4 weeks 40% %
6 weeks 35% %
Absorption - minimal until 90 days
- complete in days (6 months)

24. Lactomer (copolymers of glycolide and lactide) Polysorb
Multifilament, braided , violet / undyed, coated
TS 14 days
21 days
Absorption – days
Effective wound support – 3 weeks
Compared with Vicryl:
Easier handling
Higher Knot breaking strength
Lower knot rundown force (easier knotting)
Lower incidence of suture extrusion (less wound dehiscence)

25. Polyglyconate ( glycolic acid, trimethylene carbonate ) Maxon
Monofilament , green / undyed-clear
TS 28 days (higher than others)
42 days
Absorption – minimal until 60 days
- 6 months
Effective wound support – 6 weeks
Absorbable suture for pediatric c-v, intestine

26. Glycomer (glycolide 60%, trimethylene carbonate 26%, dioxanone14%) Biosyn
Monofilament , violet / undyed
TS 2 weeks
3 weeks
Absorption – days
Effective wound support – 3 weeks

27. Polyglytone (glycolide, caprolactone, trimethylene carbonate, lactide) synthetic polyester - CAPROSYN
Monofilament / rapidly absorbed / dyed violet
TS 5 days
10 days
21 days
Absorption < 56 days
Effective wound support – 10 days

28. Antibacterial 1- Coated Vicryl Plus Antibacterial
2- Monocryl Plus Antibacterial
3- PDS II Plus Antibacterial
Pure Triclosan /2/3/ Staphylococcus aureus Staphylococcus epidermidis Methicillin-resistant Staph. Aureus (MRSA) Methicillin-resistant Staph. Epidermidis (MRSE) /3 Escherichia coli Klebsiella pneumoniae

29. Indication – gen soft tissue approx , and/or ligation
- PDS (Polydioxanone), Maxon (Polyglycolic acid) – pediatric C-V tissue, where growth is expected
CI - where extended approx of tissue is required – c-v, neurological tissue (Safety & effectiveness – not established). Exception – see above
Precautions:
- conjunctival, vaginal, subcuticular, microsurgery, ophthalmic surgery - removed in 7 days (localized irritation) (to minimize local irritation – as remain for long period)
- elderly, cancer, anemia, malnutrition, infected wounds, mouth, vagina (fast absorption)

30. Advantages of synthetic absorbable sutures
High initial tensile strength, Guaranteed holding power through the critical wound healing period Smooth passage through tissue Easy handling Excellent knotting ability Secure knot tying

31. Non-absorbable

32. Silk Natural – made by silkworm larva to make its cocoon
Should be used dry – as it loses TS when exposed to moisture
Twisted or braided (multifilament)
Easy handling, tie down excellently, knot secured
In reality it is slowly absorbable suture as it loses 50% of its TS at 1 year & its undetected in tissue at 2 years

33. Stainless steel (Alloy suture)
Alloy = a substance composed of a mixture of 2 or more metals
Natural, monofilament / multifilament
Advantages: - no tissue reaction
- minimal loss of TS
Disadvantages:- difficult handling
- insecure knot
- pulling, cutting, tearing of tissue
- fragmentation, kinking, fracturing, buckling
- risk of injury / transmission of infection to personnel (tear of surgical gloves, skin puncture)
- not used with other alloy prosthesis – electrolytic reaction
Size – 40 (smallest) 18 (largest)

34. Nylon (Polyamide) Ethilon, Nurolon
Synthetic, monofilament, non-absorbable
Monofilament (Ethilon) / multifilament (Nurolon)
Clear / dyed green, blue, black
TS – 12.5% loss of TS / per year
- 15% lost at 1 year
- 25% lost at 2 years
Easier to handle than polypropylene – ideal for interrupted skin suture

35. Polypropylene (Prolene)
Synthetic, monofilament, non-absorbable
Clear / dyed blue
Very minimal tissue reaction – used in infected / contaminated tissue
Hold knots better than most other synthetic monofilament materials
Low coefficient of friction - easy knot rundown & suture passage through the tissue
Low drag coefficient in tissue than nylon sutures - ideal for continuous skin closure
TS – > 2 years

36. Poly (hexafluoropropylene – VDF) PRONOVA
Polyester blend of poly (vinylidene fluoride) & poly (vinylidene fluoride-co-hexafluoropolyprolene)
Monofilament
Blue / clear
Remains indefinitely
Used in C-V surgery

37. Polyester (Polyethylene terephthlate) MERSILENE, ETHIBOND
Synthetic, multifilament, non-absorbable
White (undyed), green
Last indefinitely
Uncoated – high coefficient of friction / coated – acceptable coefficient of friction
Best for vascular surgery
MERSILENE
ETHIBOND (extra polyester suture – coated)

38. Polybutester (Novafil) (butylene terephthalate+polytetramethylene ether glycol terephthalate)
Monofilament
Coated / uncoated
Unique feature – great elasticity & elongation – elongate under load, but return to its original length once load is over (adapt to change in wound tension) – advantage for wound closure.
Less hypertrophic scar formation
Less irritant than Nylon

39. Expanded polytetrafluoroethylene (ePTFE) GORE-TEX® Suture
A porous microstructure allows tissue ingrowth into the suture.
100 times more supple than any monofilament suture
rate of creep (suture elongation that occurs when a suture is subjected to constant load for an extended period) is significantly < polypropylene suture
breaking strength of an unknotted and knotted ePTFE suture is significantly < polypropylene or polybutester
1:1 suture : needle ratio = minimize needle hole bleeding
Monofilament
Main use with vascular grafts

40. Suture infection-potentiating effect
All sutures potentiate infection by damaging local tissue defense mechanisms:
- trauma by needle
- suturing technique – too tight sutures
- penetration of intact skin – contamination of suture wound by skin flora / added flora from pathological tissue, fluid, blood,…..
- suture’s material: * quantity of suture used (diameter, length) * suture’s chemical composition

41. Chemical composition ABSORBABLE NONABSORBABLE
Synthetic monofilament < Synthetic monofilament <
Synthetic multifilament < Synthetic multifilament <
Plain gut < Silk = cotton
Chromic gut
Monofilament < Multifilament
Synthetic < Natural

42. Of all sutures, the metallic sutures are the most reactive because of:
Of all sutures, the metallic sutures are the most reactive because of: chemical configuration - stainless steel is not as inert as pure polymers physical configuration- stiff – more damage during insertion, damage during patient’s movement – longer impairment of tissue defense
Silk & cotton – high tissue reaction
- CI in contaminated wound
- can be completely replaced by Nylon
Has no clinical use

43. Quantity of suture within the wound
Less suture = less tissue reaction = less infection
Less suture diameter (fine size = 5-0, 6-0) = less quantity
Less number of suture = less length

44. Suturing techniques Too tight sutures -
Sutures under tension - ↓ blood supply - ↑ infection + disruption
S-C closure by any suture - ↑ infection
Skin sutures: - percutaneous
- dermal (subcuticular)
Percutaneous ± dermal
Percutaneous - monofilament nylon or polypropylene - least damage to the wounds' defenses
- least number of sutures
- least diameter – according to skin tension

45. Infection rate with dermal closure – debate:
- ↓ or completely prevents the normal serosanguinous discharge i.e. remain in the wound serving as a culture medium for bacteria - ↑infection
- more resistant to exogenous bacterial contamination than percutaneous closure
- if infection occurs, pus will spread in the entire wound before it becomes clinically apparent (with interrupted percutaneous suture – localized collections, exist through wound edges before spreading between the divided s-c fat)
- percutaneous suture – migration of skin bacteria into wound

46. Suture selection Wound characteristics: Wound tension:
- high tension (abdomen) – non-absorbable
- low tension (chest) – absorbable
Risk of expansion, stretching, distension (abdomen)– non-absorbable
Contaminated / infected – avoid multifilament, use monofilament AS (suture act as a foreign body – AS act for shorter time), support with non-absorbable
Blood supply – poor (cartilage) – avoid absorbable - suture extrusion & delayed absorption
Wound type – heart, vessels > 2mm, nerves – safety & effectiveness of absorbable suture are not established
- wound containing salt solution (biliary & urinary tracts) – risk of calculus formation as suture acts as a foreign body (use rapidly AS, AS act for shorter time than NAS)

47. Tissue type:
- tissues that heal slowly (fascia, tendons) – NAS / AS that persist > 6/12
- tissues that heal rapidly (stomach, colon, bladder) -AS
Patient’s condition – malnourished, elderly, debilitated (delayed wound healing) – avoid absorbable
Surgeon preference, experience
Surgical techniques:
- subcuticular – absorbable suture should be placed deeply to minimize erythema & induration
Cosmetic suture
- aim – close & prolonged apposition of the wound
- avoidance of irritant suture (use inert suture)
- use smallest inert monofilament (Nylon / Polyprolene)
- avoid skin suture, use subcuticular when possible

48. Thank You

49. Needles
Should be:
- sharp enough to penetrate tissue with minimal resistance & trauma
- rigid enough to resist bending (strength = the force needed to bend the needle to 90 degree) flexible enough to bend before breaking (ductility = the ability of the needle to bend to a given angle under a given amount of pressure (load) without breaking)
- sterile & corrosion-resistance to prevent introduction of microorganisms & foreign bodies into the wound

50. Produced from stainless steel alloys + a minimum of about 12% chromium (a thin, protective surface layer of chromium oxide form when the steel is exposed to oxygen) + nickel (strength & ductility)

51. Components of a needle
1- attachment end
2- body (shaft)
3- point

52. 1- Attachment end
1- Threaded eye needles – the sutures is threaded through the needle’s eye
Disadvantage – substantial tissue trauma (large holes in tissues, large drag force)
2- Eyeless needles = swage needles = suture is attached to a drilled hole in the needle:
Advantage - less tissue trauma (smooth needle-suture junction, small holes in tissues, low-drag force)
- mechanical-drilled needles (channel needles) – for large size needles
- laser-drilled needles – for small & large size needles

53. Advantages of laser-drilled over mechanical-drilled needles:
- smoother needle-suture junction (less tissue trauma)
- lower drag force
- shorter length of the swage (by 4x; 1.5mm/6mm for 18mm long needle) – can be grasped near the swage without inducing breakage or bending – easy manipulation of the needles through the tissue)
Sutures are fixed into the holes by compressing the walls of the swage against the suture.
Separation of the needles from the suture – cutting of the suture
Control release needle suture (pop-off control release) – sutures fixed into the swage by low compression force - fast separation of the needle from the suture (by slight pull on the needle-holder)

54. Body – part that is grasped be the needleholder
- diameter as close to the diameter of the suture
Security with which needle holder jaws grasp the needle depends on: presence of teeth in the needle holder jaws - ratchet setting of the needle holder handle - shape of the cross-sectional area of the needle body
Shape of the cross-sectional area: circular, oval, triangular, rectangular (flattening the sides, flattening the top and bottom), trapezoidal
Longitudinal ribs on the inside or outside surfaces (greater stability of the needle in the needle holder)

55. Curvature – straight, half-curved (ski), ¼ circle, 3/8 circle, ½ circle, 5/8 circle, compound curved
The radius of the needle is the distance from the centre of the needle to the body of the needle, if the curvature of the needle was continued to make a full circle.
Radius with 90° (1/4), 135° (3/8), 180° (1/2), 225° (5/8)

56. Curvature helps selecting the appropriate needle according to the depth of the tissues where to be used (135° (3/8), appropriate for skin, while 180° (1/2) for deep cavity)
A compound curved needle has two distinct radii of curvature. The type curvature of its tip extends 35° before it assumes a regular uniform curvature in the remaining portion of the needle body (100°).
The tight needle curvature at the point permits rapid, accurate needle passage at a selected depth and allows controlled exiting.
Used in ophthalmic, vascular, microvascular surgeries & dermal & skin closure.

57. Surgical needle is also characterized by:
1- chord lengthlinear = distance from the central point of the needle swage to the point of the needle.
2- diameter = width of the original circular wire utilized in the manufacturing process for the production of the needle.
3- Needle length =the arc length of the needle measured at the centre of the wire's cross-section.

58. Point – extends from the extreme tip of the needle to the maximum cross-section of the body
Taper, cutting or combination of both.
Taper (needle body is round and tapers smoothly to a sharp tip)
It spreads the tissue without cutting it.
Used in soft tissue that do not resist penetration – vessels, abdominal viscera, fascia.

59. Cutting (needle body is triangular and has at least two opposing cutting edges on the inside)
Reverse cutting (needle body is triangular and has at least two opposing cutting edge on the outside)

60. Tapercut or trocar point (needle body is round and tapered, but ends in a small triangular cutting point)
Main use in cardiothoracic, vascular (calcified, fibrotic vessels, oral mucosa

61. Blunt point = it has no taper at all (do not taper to either a sharp or dull tip)
Used for sewing friable tissues (liver, spleen)
Spatula point or side cutting (flat on top and bottom with a cutting edge along the front to one side) for eye surgery

62. Needle selection:
- type of tissue to be sutured
- location & accessibility
- size of the suture material
- surgeon’s preference

63. Thank You