Suture materials and principles of suturing Dr. Bara Sultan B.D.S,M.Sc,F.I.C.B.S

Suturing The purpose of suturing are : 1 – to hold the wound margins together to promote wound healing by first intention. 2- to approximate the wound margin to minimize wound contamination with food debris 3 – to arrest hemorrhage

Needles Needles are of 2 shapes : straight and curved. The straight needle require large spaces for manipulation and are of little importance to an oral surgeon. Curved needles are of round or cutting type ( according to the cross section of the needle). The curved cutting needle are a\conventional cutting type or b\ reverse cutting type.

Surgical Needle Curvature * Most common, general use in all tissues ¼ 3/8 * ½ * 5/8 J-shaped

The conventional has one of its cutting edge on the curved inner surface. While reverse cutting has a flat inner surface.

Principles of suturing 1- The needle is grasped with a needle holder at its 2\3 of its curvature .it never held by the eye or the point 2- the area to be sutured is dried with a sucker or cotton swab so that the cut edge are clearly visible . 3- suturing from the movable to the fixed wound margin 4- toothed dissecting tweezers are used to grip the flap and fix it .

Needle Holder Remember!!! Thumb & ring finger into needle holder’s rings (NOT your middle finger!)

Index finger stabilizes the instrument by resting on the shaft.

Surgical Scissors

5- the needle should pass at least 3 mm from the wound margin 6- the knots should be lied at one side of the wound margin. 7- the knots should be not too tight and not too loose .

suture removal The suture should be remain in situ for up to 7 days They should be removed by grasping of the knots and cutting the suture where it enter the tissues . If the suture is cut at a distance from point of entry into the tissues contaminated suture material may be dragged through the healing wound thus infecting it .

SUGGESTED REMOVAL TIME (days) Area 3-5 Face 5-8 Neck 7-9 Scalp 8-14 Upper limb 10-14 Trunk 14 Ext. surface hand 14-28 Lower limb TABLE 1 Suggested Removal Times for Interrupted Skin Sutures AreaRemoval time (days)Face3 to 5Neck5 to 8Scalp7 to 9Upper extremity8 to 14Trunk10 to 14Extensor surface hands14Lower extremity14 to 28 April 17

Properties of suture materials

1- CONFIGURATION The number of strands of material used to fabricate the suture: The configuration is based on the number of strands of material used to fabricate the suture; a suture can be monofilament (ie, single-stranded) or multifilament (ie, multistranded) Monofilament Multifilament April 17

2- SIZE Denotes the diameter of the material. Use the smallest suture size that will adequately hold the wounded tissue. Minimizes trauma. Minimum mass of the foreign material. The accepted surgical practice is to use the smallest diameter suture that will adequately hold the mending wounded tissue. This practice minimizes trauma as the suture is passed through the tissue to effect closure. It also ensures that the minimum mass of the foreign material is left in the body  April 17

SIZE Diameter (mm) Metric scale Size 0.5 5 2 0.4 4 1 0.35 3.5 0.3 3 0.3 3 2/0 0.2 3/0 0.15 1.5 4/0 0.1 5/0 April 17

3- TENSILE STRENGTH The weight required to break a suture divided by its cross-sectional area. The ability of suture material to keep tissues approximated. The rate of tensile strength loss is not the same as its absorption and varies among suture materials. The tensile strength of a material is determined by the weight required to break a suture divided by its cross-sectional area. The rate of tensile strength loss is not the same as its absorption and varies among suture materials.. The implantation and tying of sutures decrease their strength Knotted sutures have two thirds the strength of unknotted sutures. In selecting sutures, remember that the tensile strength of a suture does not need to exceed that of the tissue it is securing April 17

4- PLASTICITY Ability of the suture to retain its new form and length after stretching. Allows a suture to accommodate wound swelling and therefore decreases the risk of strangulated tissue and crosshatch marks. Plasticity is the:… Plasticity…... However, as swelling subsides, the suture retains its new size and may not continue to adequately approximate the wound edges. April 17

5- ELASTICITY Ability of a suture to regain its original form and length after stretching. After the swelling of a wound recedes, the suture returns to its original length and keeps the wound well approximated. Most sutures are elastic; few are plastic. is the … April 17

6- MEMORY The ability of a suture to return to its original shape after its deformation by tying. A suture with a high degree of memory, particularly a monofilament suture, is. Stiff. Difficult to handle. The knots are less secure. They may require an extra throw to prevent loosening of the knot. Memory is…. Memory is …A suture with a high degree of memory, particularly a monofilament suture, is stiff and difficult to handle; the knots are less secure, and they may require an extra throw to prevent loosening of the knot. April 17

THE CHOICE OF PROPER SUTURE MATERIAL The optimal suture has the following criteria: 1- Easy to handle. 2- Has high tensile strength and knot security. 3- Any tissue reaction should be minimal. easy to handle and has high tensile strength and knot security. Any tissue reaction should be minimal, and the material should resist infection and have good elasticity and plasticity to accommodate wound swelling. A low cost is preferred April 17

THE CHOICE OF PROPER SUTURE MATERIAL 4- The material should resist infection 5- Have good elasticity and plasticity 6- A low cost is preferred easy to handle and has high tensile strength and knot security. Any tissue reaction should be minimal, and the material should resist infection and have good elasticity and plasticity to accommodate wound swelling. A low cost is preferred April 17

TYPES April 17

Suture Material 3 ways of classifying suture material: Natural or Synthetic Absorbable or Non-Absorbable Monofilament or Braided/Twisted

Polypropylene Polyester Silk Catgut Natural Silk, linen, catgut Synthetic polymer Polypropylene, polyester, polyamide Polypropylene Polyester

Absorbable Non-Absorbable catgut, polydioxanone, polyglycolic acid Used for deep tissues, membranes, & subcuticular skin closure Non-Absorbable polyester, nylon, stainless steel Used for skin (removed) & some deep structures (tendons, vessels, nerve repairs – not removed)

Monofilament Polypropylene Polydioxanone Nylon Multifilament Catgut (twisted) Polyester Silk (braided)

Suturing techniques 1-simple interrupted . 2- continuous . 3- continuous interlocking or blanket . 4- figure of eight. 5- Sling suture.

SIMPLE INTERRUPTED suture

Simple interrupted sutures In this type of suturing the needle is passed from one side to the other side of the incision and the knot- tied. If there is loosening or break of a stitch it does not affect the others. If for some reason like infection ,stitch is to be removed .it is not necessary to remove the complete suturing , the removal of only a few is sufficient.

GENERAL PRINCIPLES OF KNOT TYING The knot must be as small as possible. Final tension on final throw should be as nearly horizontal as possible. Ends should be cut as short as possible. Sutures used for approximation should not be tied too tightly. General Principles of Knot Tying Certain general principles govern the tying of all knots and apply to all suture materials. 1. The completed knot must be firm, and so tied that slipping is virtually impossible. The simplest knot for the material is the most desirable. 2. The knot must be as small as possible to prevent an excessive amount of tissue reaction when absorbable sutures are used, or to minimize foreign body reaction to nonabsorbable sutures. Ends should be cut as short as possible. 3. In tying any knot, friction between strands ("sawing") must be avoided as this can weaken the integrity of the suture. 4. Care should be taken to avoid damage to the suture material when handling. Avoid the crushing or crimping application of surgical instruments, such as needleholders and forceps, to the strand except when grasping the free end of the suture during an instrument tie. 5. Excessive tension applied by the surgeon will cause breaking of the suture and may cut tissue. Practice in avoiding excessive tension leads to successful use of finer gauge materials. 6. Sutures used for approximation should not be tied too tightly, because this may contribute to tissue strangulation. 7. After the first loop is tied, it is necessary to maintain traction on one end of the strand to avoid loosening of the throw if being tied under any tension. 8. Final tension on final throw should be as nearly horizontal as possible. 9. The surgeon should not hesitate to change stance or position in relation to the patient in order to place a knot securely and flat. 10. Extra ties do not add to the strength of a properly tied knot. They only contribute to its bulk. With some synthetic materials, knot security requires the standard surgical technique of flat and square ties with additional throws if indicated by surgical circumstance and the experience of the surgeon. An important part of good suturing technique is correct method in knot tying. A seesaw motion, or the sawing of one strand down over another until the knot is formed, may materially weaken sutures to the point that they may break when the second throw is made or, even worse, in the postoperative period when the suture is further weakened by increased tension or motion. April 17