Moles are very common in Singapore. Almost everyone has a mole, and more often than not, a pesky mole that they want to be removed. Even patients that have not considered doing any sort of medical aesthetics treatments are often open to mole removal.

Often, patients in Singapore considering mole removal would seek laser mole removal. However, some moles should not be lasered but excised instead. Mole removal using surgical excision allows the complete removal of all abnormal mole cells and gives us the chance to examine the tissues to rule out cancer.

The Problem with Mole Excisions

Moles can come in all shapes and sizes. You may or may not have noticed but more often than not, they are circular. This presents a problem because directly stitching together a circular defect results in an unsightly skin deformity known as a dog-ear in which excess skin pouches around the ends of the incision.

Dog-ears are simply a result of geometry. Traditionally, plastic surgeons would plan for an elliptical excision hidden in the wrinkles (or 'relaxed skin tension lines', while using techniques such as layered closure to minimize spreading (or 'dehiscence') of the resultant linear scar.

However, the length of an elliptical excision is often thrice the diameter of the mole, depending on the desired orientation of the final scar. This is often surprisingly much longer than the patient expects and can accept.

Other than the length of the scar, another issue is widening or spreading of the scar. Plastic surgeons often 'undermine' the surrounding tissues widely and use buried absorbable sutures to support the wound while the scar strengthens. Nonetheless, movement (especially on the face) still tends to stretch out the scar. Furthermore, the buried sutures have a tendency to be pushed out or extruded towards the surface.

New Surgical Techniques for Better Mole Excisions

Numerous surgical techniques have been devised to overcome the problems highlighted and ensure better mole excision outcomes. The following curated list of techniques are ones that I find effective and use on a regular basis, not just for surgical excisions for mole removal but for other lumps, bumps or scars as well.

Start with Round Excision

Multiple studies have shown that starting with circular excisions result in shorter, better-orientated scars with greater preservation of normal healthy skin tissue.

Personally, I prefer to use the CO2 laser for mole excision instead of a punch biopsy tool. Firstly, CO2 laser cauterizes as it cuts, reducing bleeding and allowing better visualization. Secondly, the CO2 laser produces ablation and coagulation in addition to cutting, which helps destroy mole cells at the excision margin ensuring better clearance and lowering the risk of recurrence. Lastly, unlike the punch biopsy tool which produces wounds of a fixed shape and size, the CO2 laser can be used in a freehand manner closely following the mole margins. This preserves more healthy tissue and creates a more irregularly shaped wound that is less obvious than a straight scar.

Stretching the skin perpendicular to the normal wrinkles of the skin helps to reduce the amount of dog-ear formation. Following excision, adequate undermining around the margins of the wound often allows the wound to determine its own appropriate orientation, resulting in a more natural-looking scar.

Prevent Scar Widening

While excising the mole with the laser, it is also important to ensure that the wound edges are bevelled away from the centre of the wound to facilitate approximation of the wound edges.

After excising the mole and preparing the wound, it is time to start the closure proper. Many surgeons that work on non-facial areas often close the skin with a single layer of sutures or even staples. Plastic surgeons and other surgeons that are trained to close wounds on the face often do layered closure which provides prolonged support to the scar, preventing widening over time.

Many doctors that do layered closure use polyglactin (Vicryl) absorbable suture material to place buried vertical mattress sutures very close to the skin surface, at the junction between the epidermis and dermis. I used to do this a lot too when I was on plastic surgery calls in SGH. While this approach can produce good apposition and support the wound, it may lead to suture 'spitting' (in which suture material is pushed out to the skin surface) particularly on the face which has a tendency to do this. Furthermore, Vicryl only retains strength for about a month and is completely absorbed within 3 months.

Nowadays, I prefer to use polydioxanone (PDS) which lasts much longer and can provide support for twice as long. My experience has shown that using this expensive but longer-lasting suture to place set-back buried dermal sutures deeper in the skin results in better wound healing and less chance of suture spitting.

Dog Ear Management

After round excision, undermining and closing the deep layers securely, there is often very minimal dog-ear deformity left. Depending on how the wound looks and lies, we can then manage the dog-ear accordingly.

Serial Halving

If there is minimal dog-ear remaining, closure by serially halving the incision effectively distributes the excess tissue from the dog-ear across the length of the incision. This technique works better in longer incisions with minimal dog-ears and can be combined with dog-ear pexing sutures.

Dog-Ear Pexing Sutures

Dog-ear pexing or suspension suture techniques fix down the protruding excess tissue from dog-ear instead of removing them and extending the wound. Examples include the dog-ear tacking suture, 'leashing' suture, three-bite technique and diagonal mattress suture.

Each dog-ear pexy technique works differently and is suitable for different scenarios and dog-ear configurations. To get the best result, it is important to tailor the approach to the wound location, length and the presence of any important structures around the wound.

Excisional Techniques

Sometimes, the amount of excess tissue is just too much. Despite meticulous planning, preparation and execution of tissue-preserving techniques, a dog-ear still forms necessitating excision of the excess tissue.

Traditionally, a triangular piece of tissue, known as a Burow’s triangle is removed from the end of the incision increasing the final length of the incision. New techniques such as nested M-plasty, modified M-plasty, modified bowtie closure or inverted triangle repair can help to reduce the amount of healthy tissue lost and limit the length of the scar.

Regardless of the excisional technique used, the scar will be longer than the initial incision. When choosing which of the various excisional technique to use to correct the dog-ear deformity, the technique that saves the most tissue or produces the shortest scar is not always the best. It is also important to consider how the final scar shape is integrated into the surrounding facial features, natural lines and wrinkles.

Round closure

Round closures are another option in the arsenal of plastic surgical techniques. Unlike linear closure techniques, these methods produce a smaller scar than the original wound. Examples include purse-string closure and pentagram suture.

One drawback is that such techniques can produce pronounced ripples and creases in the surrounding skin that largely smooth out over the course of months. This may not be acceptable to patients removing moles for aesthetic reasons. Hence these are not frequently used.

Secondly, while round closure results in a shorter scar than linear closure, tension in the centre of the wound may lead to a round or star-shaped central scar which may sometimes be more visible than a well concealed linear scar.

Conclusion

Surgical excision of moles may sometimes be preferred to laser mole removal. Meticulous suturing and closure can make the difference between a visible, obvious scar and thin imperceptible scar.

It is important to have a range of techniques that can be applied depending on the resulting mole excision wound, so as to minimize the length and optimize the shape of the scar.

Aftercare, including blending with laser, peri-procedural neurotoxin, topical medications also help but I shall go into that topic another time.

Do you have more questions about surgical mole removal or excisions? I enjoy suturing and wound closure as well as the creativity it entails. Please feel free to drop me a message!

References

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3. Kang AS, Kang KS. A Systematic Review of Cutaneous Dog Ear Deformity: A Management Algorithm. Plast Reconstr Surg Glob Open. 2020 Sep 23;8(9):e3102.
4. Beroukhim, K., Sklar, L. R., & Eisen, D. B. (2018). Surgical Pearl: Reverse Beveling to Improve Wound Edge Apposition. Journal of the American Academy of Dermatology.
5. Kantor J. The set-back buried dermal suture: an alternative to the buried vertical mattress for layered wound closure. J Am Acad Dermatol. 2010 Feb;62(2):351-3.
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7. Jaber O, Vischio M, Faga A, et al. The three-bite technique: a novel method of dog ear correction. Arch Plast Surg. 2015;42:223–225
8. Dhandha MM, Mishra T, Whitney DH. Use of the diagonal mattress suture to prevent dog-ear formation. J Am Acad Dermatol. 2015 Jul;73(1):e27-8.
9. Asken S. A modified M-plasty. J Dermatol Surg Oncol. 1986 Apr;12(4):369-73.