Sutures

Question 1

Lazy S Excision

Answer 1

• The basic principle of camouflaging a scar in cutaneous surgery is to break up a straight line.
• Last week you learned how to curve a line.
• The lazy S excision is another way to break up a straight line, by making two curves.
• The lazy S configuration allows the wound to be closed without the formation of dog-ears.

Question 2

Curving the Ellipse

Answer 2

You may choose to curve the line of closure to match or to parallel relaxed skin tension lines (i.e. around the eye or mouth).
Plan and diagram one side of the ellipse shorter than the opposite side.
Excise the ellipse, and undermine.
NOTE: The degree of undermining on each side of the ellipse determines its ultimate configuration.
Using the rule of halves, close the center of each side of the ellipse with an interrupted stitch, as shown in the third diagram.
Then continue using the rule of halves for closure.
The bottom drawing shows that undermining the shorter side of the excision more than the longer curve accentuates the greater curve, often producing an improved cosmetic effect.

Question 3

M-Plasty (Crown Closure)

Answer 3

The third basic variation of the ellipse.
Sometimes called the crown closure, is invaluable to the cutaneous surgeon.
Essentially a length-shortening maneuver.
By making an M-plasty, the total length of the ellipse can be shortened by 1/4.
Can also be used to remove a dog-ear or to shorten the area of a flap.

The figure on the right illustrates the ideal geometry for an M-plasty – reemphasizes the importance of the 30-degree angle in the geometry of skin closure.
The figure shows the creation of two 30-degree angles when the “M” is made.
An M-plasty at one end of the incision, shortens the length of the scar by 1/4.
Always diagram the entire fusiform excision first, before drawing the “M”

Draw an ellipse on the pig.
Draw two 30-degree angles as shown on one end as shown in the second figure.
Make your incision, cutting the tips of the” M” very carefully with scissors or scalpel, undermining the tips of the “M”.
Place an initial interrupted stitch, using the rule of halves to align the center of the ellipse for closure.
Place sutures as needed to remove tension from the tip of the M.
Next, close the tip of the M using a three point corner (tip) stitch which results in a “Y” closure as shown in the last figure.
Finish suturing using any stitch(s) desired.

If one M-plasty can conserve the length of the tissue by 1/4, then two can conserve more.
Where possible, a double M-plasty will shorten the length of the incision by approximately 1/2.
It is outlined and performed in a fashion similar to that of the single M-plasty, with the same geometry, only an “M” is made at both ends of the ellipse.