Simple suturing technique

Basic suturing principles

Many varieties of suture material and needles are available to the cutaneous surgeon. The choice of sutures and needles is determined by the location of the lesion, the thickness of the skin in that location, and the amount of tension exerted on the wound. Regardless of the specific suture and needle chosen, the basic techniques of needle holding, needle driving, and knot placement remain the same.

• Needle construction

  • The needle has 3 sections. The point is the sharpest portion and is used to penetrate the tissue. The body represents the mid portion of the needle. The swage is the thickest portion of the needle and the portion to which the suture material is attached.
  • In cutaneous surgery, 2 main types of needles are used: cutting and reverse cutting. Both needles have a triangular body. A cutting needle has a sharp edge on the inner curve of the needle that is directed toward the wound edge. A reverse cutting needle has a sharp edge on the outer curve of the needle that is directed away from the wound edge, which reduces the risk of the suture pulling through the tissue. For this reason, the reverse cutting needle is used more often than the cutting needle in cutaneous surgery (see image below).
    Diagram of a needle.
    
• Suture placement

  • A needle holder is used to grasp the needle at the distal portion of the body, one half to three quarters of the distance from the tip of the needle, depending on the surgeon's preference. The needle holder is tightened by squeezing it until the first ratchet catches. The needle holder should not be tightened excessively because damage to both the needle and the needle holder may result. The needle is held vertically and longitudinally perpendicular to the needle holder (see image below).
    
     
    The needle is placed vertically and longitudinally perpendicular to the needle holder.
    
  • Incorrect placement of the needle in the needle holder may result in a bent needle, difficult penetration of the skin, and/or an undesirable angle of entry into the tissue. The needle holder is held by placing the thumb and the fourth finger into the loops and by placing the index finger on the fulcrum of the needle holder to provide stability (see first image below). Alternatively, the needle holder may be held in the palm to increase dexterity (see second image below).
    The needle holder is held through the loops between the thumb and the fourth finger, and the index finger rests on the fulcrum of the instrument.
    
    The needle holder is held in the palm, allowing greater dexterity.
    
  • The tissue must be stabilized to allow suture placement. Depending on the surgeon's preference, toothed or untoothed forceps or skin hooks may be used to gently grasp the tissue. Excessive trauma to the tissue being sutured should be avoided to reduce the possibility of tissue strangulation and necrosis. Forceps are necessary for grasping the needle as it exits the tissue after a pass. Prior to removing the needle holder, grasping and stabilizing the needle is important. This maneuver decreases the risk of losing the needle in the dermis or subcutaneous fat, and it is especially important if small needles are used in areas such as the back, where large needle bites are necessary for proper tissue approximation.
  • The needle should always penetrate the skin at a 90° angle, which minimizes the size of the entry wound and promotes eversion of the skin edges. The needle should be inserted 1-3 mm from the wound edge, depending on skin thickness. 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 also exit the skin perpendicular to the skin surface.
• Knot tying

  • Once the suture is satisfactorily placed, it must be secured with a knot. The instrument tie is used most commonly in cutaneous surgery. The square knot is traditionally used. 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 counterclockwise 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 approximate the wound edges without constricting the tissue. Sometimes, leaving a small loop of suture after the second throw is helpful. This reserve loop allows the stitch to expand slightly and is helpful in preventing the strangulation of tissue because the tension exerted on the suture increases with increased wound edema. Depending on the surgeon's preference, 1-2 additional throws may be added.
  • 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 (if interrupted stitches are used), or the next suture may be placed (see image below).
    
    Knot tying.