BCID: How to Bury the Final Knot

The buried continuous intradermal closure technique

The buried continuous intradermal closure technique has recently gained popularity for use in elective veterinary surgical proce-dures because it eliminates the additional time and expense required of the veterinarian and owner for suture removal. Furthermore, rapid epithelial bridging occurs and little visible scar is produced because skin edges remain well apposed. The risk of accidental suture disruption through licking or scratching or sutureinduced irritation is reduced because no suture material is exposed to the environment.

Indications

The buried continuous intradermal technique can be successfully used to close skin wounds in various locations. General indications include clean wounds with similar adjacent healthy skin edges and thicknesses as well as wounds that can be expected to be primarily apposed without dog-ear formation, excessive tension, or a means of drainage. Skin incisions created for elective procedures, such as castration or ovariohysterectomy are ideal wounds to close with this method. Buried continuous intradermal closure of appropriate wounds is particularly indicated for primates and other laboratory animals, such as chinchillas or gerbils, because premature removal of percutaneous suture often occurs in these species. Furthermore, removal of percutaneous suture from aggressive patients may be impossible without chemical restraint.

Technique

The buried continuous intradermal suture pattern begins at one end of a skin incision with a buried knot. The dermal layer of the skin is then caught with alternating horizontal tissue bites (or loops) throughout the length of the incision. The ability to bury the knot adequately at the end of the incision is perhaps the most difficult aspect of this pattern to master.

Three-Step End-Knot Sequence

A carefully planned three-step sequence of needle passages results in a consistently buried knot and good apposition at the end of the incision. After the final horizontal needle bite is taken, the needle is advanced 2 to 3 mm to the opposite side, where it is inserted vertically from mid dermis down into the deep subcutaneous tissue (Step 1; superficial to deep direction). The needle is then inserted in the opposite side of the wound at the same deep level, exiting in the mid-dermal area within 2 to 3 mm from the commissure (Step 2; deep to superficial direction). A 2-cm loop of suture (created between Steps 1 and 2) originating deep to the dermis is raised from the wound, Finally, the needle is transferred directly to the opposing side and inserted at the same dermal position but angled deeper into subcutaneous tissue toward the base of the exposed suture loop (Step 3; superficial to deep direction). The needle is withdrawn from the incision between the exposed loop and the final suture crossing of the incision. After the exposed loop is given a gentle tug to tighten the remaining horizontal loops, the free suture end is tied to the exposed loop to bury the knot and appose the commissure. The surgeon must remember to tighten the knot by pulling the suture ends parallel to the incision.
Once sufficient throws are placed, the loop of suture is cut close to the knot. The needle is then inserted close to the knot to exit deep to the dermis 1 cm lateral to the incision. As the suture is drawn tight, the knot is inverted and pulled into deeper tissue well below the dermis. While tension is placed on the suture, it is cut flush with the surface of the skin to end the pattern.