Corner Suture

E. J. Mayeaux, Jr, MD, DABFP, FAAFP

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Subject: Corner Suture

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The corner suture (also know as the half-buried horizontal mattress suture or tip stitch) is used to securely suture the tip of a flap of skin into a matching skin defect. If the corner of the flap were to be closed using simple interrupted or running sutures, the two sutures closest to the tip would interfere with the blood supply to the tip, increasing the chance of tip necrosis. Because the corner suture secures the tip without the suture crossing the top of the incision, it does not impede blood flow and may decrease the chance of necrosis of the flap tip. 
The corner suture is based on the horizontal mattress suture, but the part that passes through the tip is buried in the dermis. It is usually performed using 3-0 to 5-0 nonabsorbable sutures to minimize inflammation in the flap tip. Like most mattress sutures, consider removing the corner sutures earlier than the other sutures in the closure, because the part of the corner suture crossing the surface of the skin may cause damage and scarring if removal is delayed. This is less of a problem with corner sutures than with vertical mattress sutures (see Appendix J). 
The main disadvantage of the corner suture is that close approximation of wound edges without trauma to the flap tip can be difficult. Careful control of the tension induced when tying the suture can minimize this problem. 


Common skin surgery equipment and the typical skin surgery tray are listed in Appendix G


  • Approximating the tip of a skin flap with the corresponding defect

  • Approximating corners of skin flaps when performing tissue rearrangements such as T-plasties, V-Y-plasties, and the centers of advancement flaps

  • As part of Burow’s triangle repairs, especially when suturing unequal length skin edges and when performing tissue rearrangements (such as rotation flaps, O-to-Z-plasties, and the ends of advancement flaps

Contraindications (Relative)

  • Uncooperative patient

  • Wounds best closed by other methods

  • Presence of cellulitis, bacteremia, or active infection

The Procedure

Step 1

The corner suture must be laid out correctly to achieve optimal results. It is often helpful to visualize or to draw a baseline that exactly bisects the flap tip and continues through the skin containing the defect into which the tip will be sutured. The entry and exit points of the suture will be parallel to this baseline. 

Step 2

Begin the suture on the side of the wound containing the defect into which the tip will be sutured. The suture enters through the epidermis about 4 to 8 mm from the skin edge and is passed through the dermis of the wound edge. The path of the needle should be parallel to the baseline. 
  • PITFALL: The needle should not go all the way through the skin into the subcuticular tissue, as is the case with most other suturing techniques. The path of the needle is directly into the dermis, at which level it will remain until it exits the skin before tying.

Step 3

The needle is then passed horizontally, making a 5-mm loop arcing through the end of tip in the same dermal plane, exiting on the opposite side of the flap tip. 
  • PEARL: This pass may be made with the flap in anatomical position and with the needle drivers in a vertical position. However, many providers find it helpful to gently elevate the tip between the sides of pickups (do not actually grab or apply pressure to the flap tip), placing the tip in a vertical position for this pass.

  • PITFALL: If the flap tip is grasped, the chances of tip necrosis are greatly elevated.

  • PEARL: Make sure the suture passes symmetrically through the tip for best results.

Step 4

The needle then reenters the skin to which the flap is being attached at the same level of the dermis. This pass should be parallel to the first pass and the baseline and at the same distance from the baseline as the first pass. 

Step 5

Exit the skin parallel to the entrance point along the line of pull (baseline) and tie the suture (see Basic Instrument Suture Tie). 
  • PITFALL: Be careful not to tie the suture too loosely because this will cause poor approximation of the wound edge.

  • PITFALL: Be careful not to tie the suture too tightly because this can cause bunching of the skin, over- or underriding of the flap tip, or an increased risk of scarring under the knot.

Step 6

Multiple corners may be brought together by expanding the arc of the dermal pass to include all of the tips. This is frequently used in advancement and other flaps. 
  • PEARL: Make sure the suture passes symmetrically in a smooth arc through all of the tips for best results.

Step 7

Similarly, this technique may be used to repair Y-shaped lacerations and stellate lacerations. 


  • Bleeding

  • Infection

  • Scar formation

Pediatric Considerations

Generally, pediatric skin has excellent blood flow and heals very well. However, pediatric patients often find it difficult to sit and lie still during lengthy procedures. The patient’s maturity and ability to cooperate should be considered before deciding to attempt any outpatient procedure. Sometimes it is necessary to sedate the patient to repair the laceration (see Pediatric Sedation). The maximum recommended dose for lidocaine in children is 3 to 5 mg/kg, and 7 mg/kg when combined with epinephrine. Neonates have an increased volume of distribution, decreased hepatic clearance, and doubled terminal elimination half-life (3.2 hours). 

Postprocedure Instructions

Instruct the patient to gently wash an area that has been stitched after 1 day but not to put the wound into standing water for 2 to 3 days. Have the patient dry the area well after washing and use a small amount of antibiotic ointment to promote moist healing. Recommend wound elevation to help lessen swelling, reduce pain, and speed healing. Instruct the patient not to pick at, break, or cut the stitches. Have the patient cover the wound with a nonocclusive dressing for 2 to 3 days. The dressing should be left in place for at least 48 hours, after which time most wounds can be opened to air. Scalp wounds can be left open if small, but large head wounds can be wrapped circumferentially with rolled gauze. 
Most uncontaminated wounds do not need to be seen by a provider until suture removal, unless signs of infection develop. Highly contaminated wounds should be seen for follow-up in 2 to 3 days. Give discharge instructions to the patient regarding signs of wound infection. 

Coding Information and Supply Sources

All codes listed are for superficial wound closure using sutures, staples, or tissue adhesives, with or without adhesive strips on the skin surface. If a layered closure is required, use intermediate closure codes 12031 to 12057 or complex repair codes 13100 to 13160. 
Add together the lengths of wounds in the same classification and anatomic sites. Use separate codes for repairs from different anatomic sites. Debridement is considered a separate procedure only when gross contamination requires prolonged cleansing or when appreciable amounts of devitalized or contaminated tissue are removed. 


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2008 MAG Mutual Healthcare Solutions, Inc.’s Physicians’ Fee and Coding Guide. Duluth, Georgia. MAG Mutual Healthcare Solutions, Inc. 2007.