**6. Complications**

The complication profile from the subdermal technique and resurfacing technique differ greatly and again is mainly operator dependent whether it be poor patient selection or poor user technique.

Fewer complications are seen with the subdermal techniques. Retained helium gas can cause crepitus, prolonged swelling, eye issues, and embolus. This is prevented by holding pressure at the cheek and at the clavicle to prevent extravasation. Massaging the gas out of the incision sites helps prevent swelling and

#### *Applications of Helium Plasma in Rejuvenation of the Face and Neck DOI: http://dx.doi.org/10.5772/intechopen.100162*

crepitus. Placing enough small incisions sites to help the gas escape is key to decrease swelling or crepitus.

Placement of the handpiece too close to the dermis and or moving it too slow can cause an indented scar similar to an undulating acne scar as seen in **Figure 10**. This patient had a linear subdermal scar with volume loss similar to the undulating acne scars seen in patients. This was caused by using the device too close to the dermis. The scar resolved with repeated treatments of of intense pulsed light, 1540 deep Palomar treatment, plasma rich protein injections, and hyaluronic acid injection. The technique can cause such a contraction of the dermis or fibroseptal network that it can cause the skin to bunch especially when it is too loose. This can take a few weeks to resolve ultimately leading to continued excess skin.

One of the most frustrating complications is the dissatisfied patient from lack of results which is mainly seen in the subdermal technique. This was found more when no skin was excised or platysmal work was not done. Once again the key to optimal outcomes arises from choosing the appropriate technique for the appropriate patient and detailed preoperative counseling. Patients with thick skin that when pinched has a fast recoil and has thicker subcutaneous tissue seem to have a better result with skin tightening when used subdermally than those with loose crepey like skin.

When using this device as a resurfacing procedure, there are many more chances for complications. This cannot be stressed enough, this technology in both treatment modalities is operator dependent. Time on skin is of utmost importance. Going too slowly over the skin causes deeper thermal injury and will lead to scarring. Setting appropriate energy settings dependent on the different areas of the skin and the patient's skin type plays a role in determining if they are going to have sequelae from this procedure. If the patient has thin skin, they can have hypertrophic scarring and ultimately hypopigmentation. Thicker skin patients do better having less scarring. Hypertrophic scarring is seen frequently along the jawline, upper and lower lids in a linear fashion, temples, and the triangle at the melolabial area. This is noted more where time on skin has been too long or if a patient has scratched or rubbed the area as seen in **Figure 11**. Treatment of the scarring includes IPL, 5-FU injection, 1540 deep Palomar, Kenalog injection, saline injection, silicone sheeting. At least 50% of patients developed hypertrophic scarring somewhere on the face, but 95% of those patients had resolution of scar with treatment. Everyone recommends tumescence with lidocaine prior to treatment. However, the porcine studies by Apyx shows that the use of tumescence resulted in more depth of thermal effect. This raises concerns that the use of tumescence may increase depth of injury and may be a contributing variable for increased risk for hypertrophic scarring.

Hypopigmentation is more common with two passes and can occur if the energy is higher, which more deeply embedded wrinkles require. Sometimes PRP injections can help take the alabaster appearance away, but does not completely revert the depigmentation. Transient hyperpigmentation is noted typically in darker skin patients. This has not been permanent and resolves easily with topical vitamin C, sunscreen, and hydroquinone.

Milia and erythema is seen in every patient during the healing process. Some worse than others. Milia typically go away after a few months and with the help of extractions, low dose tretinoin, adapaline, and/or benzyl peroxide washes. Erythema can be intense for the first month. If it is prolonged, it typically leads to hypopigmentation. Intense pulsed light, LED and infrared lights, and brief low dose topical steroids can help abate this. It seems to be worse after exercise or hot showers.

Itching is universal and very normal during the first and second week postoperatively and should abate. The more the patient rubs or uses ice, the itching worsens. Hydroxyzine works very well for this issue.
