NEW VIDEO: STEPS TO UNDERMINING AN ELLIPTICAL EXCISION

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THIS VIDEO will demonstrate, step-by-step, how to undermine a standard elliptical excision after excising a non-melanoma skin cancer (NMSC) to the left upper lateral arm.  Use these steps to help guide you next time you perform surgery on your patient.

STEP-BY-STEP 

STEP 1: After performing an elliptical excision removing the NMSC, lift the skin edge up using the forceps with your nondominant hand, visualizing the underside of the dermis.

STEP 2: Then, hold the scalpel with your dominant hand in an overhand grip fashion. 

STEP 3: Placing your scalpel at the underside of the dermis, starting distally, apply consistent pressure at approximately a 30 degree angle, and begin to cut as you move more proximally through the superficial to mid-adipose layer, ensuring you stay in the same plane.

STEP 3: Repeat on the contralateral side mirroring what you just did. 

STEP 4: Once the wound is appropriately undermined, it is best to have an assistant with you for maximal visualization.  Using a skin hook to lift up to visualize the underside of the dermis is less traumatic and does not cause tissue crushing compared to forceps. 

STEP 5: Start to cauterize bleeding vessels, but try to avoid cauterizing any skin edges. Remember, the pressure alone from the sutures that you will be soon placing will, ultimately, help achieve hemostasis. Understand that excessive unnecessary cauterizing, especially the skin edges, will cause increased inflammation, necrosis, and infection. 

ANATOMIC PLANE & LOCATION

Understanding the plane you are undermining is paramount to ensure you are cutting at the appropriate depth.

You do not want to be too superficial, where you are at risk of damaging vessels supplying the dermal plexus, which can decrease vascular supply and increase risk of necrosis. 

You also want to be mindful that if you are performing deeper undermining, it will provide a more robust vascular supply, but it will also put the patient at risk for more bleeding or nerve compromise.

Always understand anatomic location and underlying structures.

Recommended levels of undermining based on anatomic location:

  • Scalp: Deep to the galea aponeurotica, above the periosteum
  • Face: High fat to avoid facial nerves
  • Trunk & Extremities: Subcutaneous fat above the muscle
  • Nose: Deeper fascia or connective tissue plane

SCALPEL VS SCISSORS

I also want to notate that you can also use scissors to undermine. Through my experience, however, I prefer sharp dissection with a scalpel because it generally leads to less tissue trauma as it avoids shearing forces that may be seen with blunt or spread undermining with scissors.

This becomes provider preference through training and experience, so choose what is more comfortable to you as long as you are using the safest and most effective approach for your patient. 

ADVANTAGES, DISADVANTAGES, & PEARLS TO REMEMBER

There are advantages, disadvantages, and technique pearls to remember when it comes it undermining: 

Advantages to Undermine

  • Permits closure of large or tight defects under tension that do not close easily
  • Reduces tension across tense defects by recruiting adjacent skin for closure
  • Frees up underlying attachments that could lead to lateral and downward pull, creating “inversion” (an inverted less aesthetically pleasing and more noticeable scar)

Disadvantages to Undermine

  • Potential impact on blood supply 
  • Increases likelihood of hematoma or seroma (by creating a deadspace)
  • More time-consuming as it requires more hemostatic measures
  • Risk of nerve damage

Pearls

  • Superficial undermining may increase the risk of damage to perforating vessels supplying the dermal plexus, increasing risk of necrosis  
  • Undermine deeper may reapproximation of deeper, well-vascularized structures rather than the thin dermis and epidermis
  • Undermining may be best performed with sharp dissection (with a scalpel) due to less tissue trauma as it avoids shearing forces that may be seen with blunt-tipped surgical scissors 

Leverage Your Skills

As dermatology NPs/PAs, I hope this article and video helped you better understand surgical pearls to be mindful of when performing surgery.  Also, techniques to use when it comes to undermining.

If you are still not confident in this area, read this ARTICLE I wrote breaking down when it is appropriate to undermine. It goes over the "WHO, WHAT, WHEN, WHERE, and WHY" of UNDERMINING!

In order to be a confident surgical provider in dermatology, understanding the foundation of mindful, masterful suturing technique is critical.

Students that have taken my advanced suturing course in the past have mentioned how it has been a game changer because of the skills and knowledge they gained after.

If you want to learn more how this course will help leverage your skills, click HERE to learn more!

Until next time...

Theresa Talens DNP, FNP-C (TheresaSurgDermNP)

P.U.L.S.E. Dermatology & Procedures, Inc.

Where we believe in Precision. Ultimate Care. Leverage. Skills. Excellence.