Suturing

Intermediate procedure

• The point: The sharpest portion used to penetrate the skin.
• The body: The mid portion of the needle.
• The swage: The thickest portion of the needle and the portion to which the suture material is attached.

Skin suturing:
When suturing skin 2 main types of needles are used, “cutting” and “reverse cutting” needles. Both needles have a triangular body.
Cutting needles: have a sharp edge on the inner curve of the needle (directed upwards.)
Reverse cutting needles: have a sharp edge on the outer curve of the needle (directed downwards) which reduces the risk of the suture pulling out through the skin. For this reason Klinicians prefer reverse cutting needles for skin suturing

Suture Materials
Non-absorbable sutures are made of materials that are not readily broken down by the body. They can be made from natural materials (e.g., silk, cotton, and steel) or man-made materials (e.g. nylon and Prolene, Mersilene).
Non-absorbable suture materials need to be removed.

Absorbable suture materials are those that are broken down and absorbed by the body.
There are many synthetic absorbable materials made from polymers (e.g., Vicryl and Monocryl). Synthetic absorbable sutures tend to cause less reaction in the skin, however if you do use absorbable suture materials it is important to ensure that they are “un-dyed” (clear or white) since the absorption of dyed sutures will result in tattooing of the skin.
Klinicians prefer to use non-absorbable suture materials which have to be removed.

Suturing techniques
Needle holders:
The needle should be grasped in the tip of the needle holder about 2/3 of the way back from the point. Incorrect placement of the needle in the needle holder may result in a bent needle, difficult penetration and/or an undesirable angle of entry into the skin.
A needle holder can be held either:

• By placing the thumb and the fourth finger into the loops with the index finger on the fulcrum (joint) of the needle holder to provide stability
• Held in the palm to increase dexterity.

Placing sutures:
The needle should always penetrate the skin at a 90° angle, which minimises the size of the entry wound. The depth and angle of the suture depends on the particular suturing technique. In general, the 2 sides of the suture should become mirror images, and the needle should exit the skin perpendicular to the skin surface (forming a rectangle.) The ideal skin suture should penetrate the skin (the epidermis) and the layer just below the skin (the dermis.)

Coordinated use of the forceps and needle holder:
Efficient placement of sutures which follow the rectangular path described above requires a coordinated use of forceps and needle holder. To take best advantage of the natural curvature of the needle an alternating pronation (thumb down, little finger up) and supination (thumb up and little finger down) motion of the hand with the needle holder should be used. Hence the right hand is pronated to “cock” the needle in preparation for taking the first “bite”. The tip of the needle should penetrate the skin perpendicularly and the needle should be rotated all the way through the epidermis and dermis by supinating the right hand to rotate the needle through its arc.

A Key Maneuver:
The tip of the needle should now be seen protruding out through the skin surface. At this point, it is important to maintain the position of the skin using the forceps (by pressing down on the skin with the forceps just below the needle.) A common error here is to release the needleholder from the needle allowing the skin to go back to it’s normal position, and the needle may move back below the skin’s surface.
The key is to maintain the position of the skin while releasing the needle from the needle holder. This will maintain the position of the needle tip. After the needle is released from the needle holder, the right hand should be fully pronated before re-grasping the needle (be careful not to re-mount the needle too near to the point as this may damage the point of the needle.) The “bite” can then be completed by supinating the right hand in order to complete the rotation of the needle through the skin.

It is now necessary to reposition the needle in the needle holder before placing another suture.
To reduce the risk of a sharps injury the needle should be grasped with the forceps (not the fingers) and the needle is remounted onto the needle holder 2/3 back from the needle point.

Knot tying:
Once the suture is in place it must be secured with a knot. The square knot is traditionally used to tie off sutures. First, the tip of the needle holder is rotated clockwise around the long end of the suture material for 2 complete turns. The tip of the needle holder is used to grasp the short end of the suture. The short end of the suture is pulled through the loops of the long end by crossing the hands, such that the 2 ends of the suture material are situated on opposite sides of the suture line. The needle holder is rotated counter-clockwise once around the long end of the suture. The short end is grasped with the needle holder tip, and the short end is pulled through the loop again.
The suture should be tightened sufficiently to sit against the skin without “puckering” the skin. Sometimes, leaving a small loop of suture after the second throw is helpful. Depending on the suture material 1 – 2 additional throws can be added to the knot to secure it.
Properly squaring successive ties is important. That is, each tie must be laid down perfectly parallel to the previous tie. This procedure is important in preventing the creation of a “granny knot” which tends to slip and is inherently weaker than a properly squared knot. When the desired number of throws is completed, the suture material may be cut and the next suture placed.

Removing sutures:
When removing sutures it is important to lift the suture gently (perpendicular) from the skin using forceps to grip the knot of each suture. This will lift clean suture material out from the wound. Cut the suture material at one side of the knot at this “clean” point of the suture material (as close to the skin as possible) using clean, disinfected* scissors or a “suture removing” blade. Gently pull the suture material out through the skin making sure that no suture material is left behind.
Clean the skin and apply plasters or dressings if required.

* Scissors can be disinfected by first washing thoroughly with hot soapy water (or put them through a dishwasher cycle) before wiping their blades with alcohol or soaking them in an alcohol solution containing 70% alcohol or above.

lili (July 2008)