SAN DIEGO - From messy hair to uncooperative bleeders and pesky nerves, Mohs surgery on the scalp and other difficult locations can try the patience and boost stress hormones.
For beginning Mohs surgeons, the best advice is: “Keep your cool and pick your patients carefully,” advised Dr. Carlos Garcia. “There are certain patients you don’t want to have for your first cases, so choose carefully, and save those until you are more experienced.”
Dr. Garcia, director of surgical dermatology at the University of Oklahoma, Norman, dropped another valuable pearl to novice Mohs practitioners: Know when to call in reinforcements. For example, with primary tumors near the lacrimal system or recurrences in the acral area, “be sure to include a plastic surgeon in your plan, because these are not usually going to be beautiful when you finish.”
The scalp is a very common location for skin cancers and presents a unique set of challenges, Dr. Garcia said. As every parent with a rock-throwing child knows, any scalp wound bleeds in apparent excess of its size.
“No matter what you do, the scalp is going to bleed, and you have to be prepared,” he said. “Most of the small vessels are in the dermis, but the bigger ones are in the deeper layers, and you may be getting into those with Mohs.”
Tumescent anesthesia is a fine approach to hemostasis. “Injected into the dermis, it produces a hard surface and after 15 or 20 minutes you can do surgery with minimal bleeding. The other advantage is that it’s going to give more prolonged hemostasis as well as pain control.”
Locking sutures are another good hemostatic technique, he said. “You can use Prolene or nylon and a running or interrupted suture, but you need to lock in the suture, and you’ll get much better hemostasis from the dermal vessels.”
Hair can also increase the risk for complications. “It’s stressful enough with the bleeding on the scalp, but on top of that you have the hair to deal with,” Dr. Garcia said. “Make sure you have lots of things to take care of that – trimmers, hair clips, mousse, and gel. Do whatever you have to do to get it out of the way.”
Elastic bandages are a must for scalp surgery. “Your patient will need to keep these on during the first 24 hours after surgery when bleeding is the greatest. If you don’t have good compression and warn your patients to maintain it, you’re going to get a lot of phone calls.”
It’s not uncommon for a patient to have multiple cancers or precancerous lesions on the scalp. “My rule of thumb is to get rid of the basic component, and then if I get three epidermal layers with actinic keratosis components but no deep component, I stop the Mohs. Note in the chart that there is a small in situ that will be treated during follow-up,” he said.
Some Mohs surgeons will persist with layers even into the periosteum or bone. “I don’t do bone chiseling because technically I’m not trained to do it, and also because I’m very hesitant because there have been reports of air embolism,” Dr. Garcia said. “The veins from the surface connect very easily with the deeper sinusoidal vessels, and if you have the patient waiting for another layer and not positioned correctly, they can get changing pressure. Air can get in and they can get an embolism in the waiting room. So if you ever delve into this area, be aware of this possibility.” (Dermatol. Surg. 2009;35:1414-21).
Because scalp skin is not very pliable, repair can be a challenge. “Many times I leave these to heal by secondary intention.” It’s not a quick process, though. “If the defect goes to the bone, it’s going to take 3-4 weeks for every centimeter of the wound to completely heal.”
Dr Garcia also passed on some tips about other areas that might challenge the Mohs surgeon:
P Temple: In the temple area, hair and bleeders are the biggest issue. “Get the hair out of the way first and have a couple of mosquito clamps loaded with 4-0 or 5-0 Vicryl to tie off vessels. As a general rule, ligate any blood vessel that’s thicker than a 30-gauge needle.”
The temporal branch of the facial nerve may be at risk if the surgery is near its most superficial area – just over the malar arc. “If you transect any of the branches of the nerve ahead or in front of the external canthus, it will regenerate 100% of the time, and the patient will get full movement back. The closer you get to the preauricular area, the less likely regeneration becomes. If transection happens – and it does – the ear, nose, and throat [specialists] usually will wait 3-4 months before trying to do something about it, to see if there is any spontaneous regeneration.”