One of the most popular new activities of the Herbert S. Waxman Clinical Skills Center at ACP's Internal Medicine meetings is the incision and drainage of abscesses workshop. With the right teaching materials and a minimum of equipment, this procedure can be easily taught in the institutional or office setting.
Creating a simulated abscess is an easy and inexpensive process and can provide a surprisingly realistic model that helps teach the motor skills and steps necessary to properly incise, drain and dress an abscess. The Waxman Center model was originally developed by Thomas Rebbecchi, MD, an associate professor of emergency medicine at Cooper University Hospital in Camden, N.J., and has since been used at ACP chapter meetings as well as at Internal Medicine.
The following is a step-by-step process for creating a homemade simulated abscess model, the equipment needed for the procedure, and a guide through the procedure.
Creating the simulation pad
1 simulation skin suturing pad (simulated skin pads are available from Limbs & Things and other medical simulation suppliers)
1 utility blade or scalpel (sharp!)
1 five-inch balloon
1 tube toothpaste
1 container rubber cement glue (or other glue suitable for adhering closed cell foam)
3 or 4 clamps, binder clips or other clips suitable for clamping a half-inch thick soft object
Step 1. Use a utility knife to slice the very top of the simulated skin pad off to about three-quarters of the way down the pad. This is best done by cutting with a very sharp blade and using light strokes while pulling back on the top flap. This should leave a flap of “skin” that is about an eighth of an inch thick.
Step 2. Fill the balloon with about 1 oz of toothpaste, making sure the paste is all the way down at the rounded end of the balloon. This is best achieved by pushing the sides of the balloon down around the nozzle of the toothpaste tube until you are at the end of the balloon. Tie off the balloon as close to the toothpaste as possible and cut off the remaining balloon beyond the knot.
Hints: Make sure not to use too much toothpaste. The average abscess is not very large and you do not want too much tension under the skin pad flap when trying to glue it back down. In addition, try to remove any air that might be trapped in the balloon, as this will make the balloon stiff and also increase the tension under the “skin” flap.
Step 3. Place the balloon in the middle of the exposed cut surface of the simulated skin pad. Make sure the toothpaste-filled portion is on top of the knot so that the knot cannot be felt through the surface of the pad. The balloon knot should not be against the top surface that will be cut into during the procedure.
Step 4. Apply rubber cement liberally to the balloon and both exposed cut surfaces of the skin pad foam.
Step 5. Use clamps to clamp the top flap down against the rest of the foam pad. Don't worry if glue oozes out of the sides due to the pressure. The rubber cement can be cleaned up later once it has dried.
Allow about two to three hours for the glue to dry. If the flap starts to pull apart from the pad due to tension, apply more glue and clamp again. Pressure applied on top of the skin pad around the “abscess” lump will increase adherence of the top flap to the rest of the pad and will make for a more realistic appearance of swelling underneath the skin.
Hint: The toothpaste will start to harden in the balloon after about one or two months, so try to use the abscess simulation pads within that time period.
Performing the procedure
List of supplies and equipment (for workshop participants):
- universal precaution items
- antiseptic solution for skin cleansing
- needle and syringe for local anesthesia (small-gauge needle, 25 g)
- 1% or 2% lidocaine with or without epinephrine
- scalpel blade (#11 preferable)
- culture swabs
- curved hemostats
- syringe and 18-g angiocatheter for irrigation with nonsterile saline
- gauze for packing (one-quarter or one-half inch), medicated or plain
1. Obtain consent
- Review possible complications and alternative treatments
2. Clean skin
- Prepare site with antiseptic solution (e.g., povidone-iodine)
3. Anesthetize skin
- Inject 1% or 2% lidocaine with or without epinephrine at surface area to be incised, or perform local field block
- Consider oral or parenteral pain medication
4. Incise abscess
- Stab incision with scalpel at center of the abscess
- Incise one-half to three-quarters the length of the abscess along existing skin tension lines
5. Culture wound
6. Facilitate wound drainage
- Gently compress abscess
- Disrupt loculations with hemostat
7. Irrigate wound
- Inject nonsterile saline via syringe and soft angiocatheter
8. Pack wound
- Pack all four quadrants with gauze
9. Dress surgical site
- Apply dressing
10. Provide patient instructions for follow-up care