Chapter 5.2: The Depth-Correcting Simple Interrupted Suture

Step-off correction suture

This technique is used to correct depth disparities when the depth of the epidermis on each side of an incised wound edge is significantly different. This problem usually stems from inaccurate placement of deeper sutures, though it may also occur as the result of differential dermal thicknesses in certain anatomic locations, such as the boundary of the lateral nose and medial cheek.

With all techniques, it is best to use the thinnest suture possible in order to minimize the risk of track marks and foreign-body reactions. Since this technique is used to fine-tune epidermal depth and is therefore not designed to hold a significant amount of tension, a 6-0 monofilament suture is often appropriate. In areas under greater tension, such as the trunk and extremities, a 5-0 monofilament suture material may be used as well.

1. The needle is inserted perpendicular to the epidermis, approximately one-half the radius of the needle distant to the wound edge.

2. If the side of the wound where the needle is first inserted is higher than the contralateral side, a shallow bite is taken, with the needle skimming the dermal-epidermal junction and exiting in the center of the wound. If the side where the needle first enters is lower than the contralateral side, a deep bite is taken, with the needle exiting through the deep dermis or into the undersurface of the dermis, depending on the degree of desired correction.

3. The needle body is grasped with surgical forceps in the left hand and pulled medially with the surgical forceps as the body of the needle is released from the needle driver.

4. The needle is reloaded on the needle driver, and the contralateral wound edge is gently reflected back with the forceps.

5. If the second side of the wound is deeper than the first, then depending on the required degree of depth correction, the needle is inserted either through the underside of the dermis or laterally through the deep dermis on the contralateral side of the wound. If the second side is higher than the first, a superficial bite is taken, through the dermal-epidermal junction if needed, to permit correction.

6. The needle is rotated and exits through the epidermis, equidistant from the incised wound edge relative to the first bite.

7. The suture material is then tied off gently, with care being taken to minimize tension across the epidermis and avoid overly constricting the wound edges (Figures 5-2A, 5-2B, 5-2C, 5-2D, 5-2E).

This suture technique is very useful for correcting depth disparities between the two sides of a wound. This may be helpful as it is often far easier to fine-tune depth disparities by adding this suturing technique than it is to remove a less-than-ideally placed deeper suture.

The depth-correcting simple interrupted suture may be used layered over the top of another suture in order to fine-tune the depth of epidermal approximation. For example, if a vertical mattress suture were placed to facilitate eversion, occasionally the wound edges remain at slightly different depths. A small depth-correcting simple interrupted suture, placed at the point where the wound edges are most unequal, may be used to solve this problem and effect accurate approximation of the wound edges.

This technique may also be used in the context of a simple running suture technique, as it can be placed over the top of the simple running sutures to equalize the depth or it can be incorporated into the running sutures themselves so that interspersed between traditional simple running bites (entering and exiting lateral to the wound at 90 degrees) some depth-correcting bites are taken as well to equalize the relative depths of the epidermis on either side of the wound. This allows the surgeon to minimize the number of ties necessary, though it should only be used when the wound is under minimal tension, since the security of the depth correcting bite may be compromised by an increase in laxity across the wound surface over time and the unpredictability of suture material stretch.

This technique can be very useful in correcting slight imperfections in the equality of the depth of wound edges. Ideally, however, this technique should be employed infrequently, since as long as the deeper sutures are placed accurately and appropriately, it should only rarely be necessary.

Therefore, caution should be exercised to avoid utilizing this technique as a crutch; as long as the surgeon appreciates that the use of this approach should be the exception, rather than the rule, it is acceptable, but it should not be utilized in lieu of attention to detail and precise placement of deeper sutures.

Some anatomic locations, however, may intrinsically present the surgeon with areas of differential dermal thickness, in which case unless the dermal sutures were placed differentially, depth-correcting simple interrupted sutures may be needed. This includes areas such as the nasal sidewall, the cheek-eyelid junction, and nasofacial sulcus, as well as other skin fold areas.

Finally, caution should be exercised to avoid over-sewing areas with the goal of correcting slight imbalances in epidermal depth. While one or two depth-correcting sutures may be necessary, moderation is key as each suture introduces additional foreign-body material and has the potential to induce an inflammatory response.