The application of laser light of different wavelengths, especially for the treatment of superficial skin lesions, has a long tradition. A lot of experience and literature can be drawn upon, particularly in the therapy of capillary malformations.
The appeal is the relatively low invasiveness of the procedure when it is properly applied, but in return its effectiveness is limited.
An interdisciplinary team should determine whether laser therapy is indicated for treating vascular anomalies and should plan such therapy. Through close coordination between the different specialist disciplines, the broad spectrum of today’s different therapeutic modalities is made available in a way that best suits patients’ needs. Given the broad range of invasive measures now available, this method is today one alternative among many. In view of the continuous further development of other invasive and medicinal forms of therapy, the overall indications for laser therapy in vascular anomalies have not been extended at present.
Especially in the case of laser therapy, given its complexity, patients should definitely be treated in a center of expertise where specific experience with laser in vascular malformations exists.
The expenditure of laser fibers using various light sources (examples: argon, diode laser, neodymium:yttrium-aluminum-garnet Nd:YAG laser 1064 nm, potassium titanyl phosphate frequency-doubled Nd:YAG 532 nm laser, copper vapor laser, flashlight pumped pulsed dye laser and broad spectrum intense pulsed light sources) essentially leads to an input of energy into the tissue. Depending on the wavelength used, light intensity and pulsation (pulse frequency, pulse duration) of the irradiation, there is heating, sometimes also vaporization, with a thermally destructive tissue reaction (photodisruption). The penetration depth of the light is usually limited to a few millimeters, but the thermal effect can spread up to a few centimeters. The increased temperature results in the formation of intravascular gas bubbles with damage to the vessel wall and subsequent thrombotic occlusion of the vessel.
It is important to know that directly after laser therapy on the skin, the desired disruption of small capillaries can lead to the formation of purpura. The cause is a spot-like hemorrhage in the skin in the area of the direct laser application due to extravascular leakage of erythrocytes. This purpura usually disappears spontaneously within days to a few weeks.
Classically, percutaneous laser therapy is performed on the skin with small point or circular light applications. To protect the skin surface, the skin is often additionally cooled by means of a cold spray or by a transparent ice block. Since the laser light is not always in the humanly perceptible and thus visible spectrum, the emerging laser light is often accompanied by a visible red or green pilot laser to make the effective area of irradiation optically visible. During application, the intervention room must be specifically marked as a laser site. Wavelength-matched laser safety goggles must be worn by all persons present.
Endovascular laser applications (e.g., using the Nd:YAG 1064 nm or diode laser 810 nm) have successfully been used to treat dysplastic, tubular, epifascial, and subfascial venous malformations and marginal veins. The laser fiber is advanced into the vessel itself under sonographic, fluoroscopic or MRI guidance, and thermal coagulation occurs by delivery of laser light.
In interstitial laser application, the laser fiber is introduced through a puncture cannula into the target lesion, which is usually located deeper in the tissue, and thus this tissue is heated in the depth around the light emission area of the laser fiber. During retraction of the laser fiber, several applications are performed by pulling back a Nd:YAG laser (1064 nm) in a bare-fiber technique (direct frontal light emission from the laser fiber tip).
Laser fibers with correspondingly small diameters and high flexibility can also be advanced through working channels of endoscopes to the target tissue (e.g., in gastroscopy, colonoscopy, bronchoscopy, cystoscopy, colposcopy).
The most common indication is percutaneously performed laser therapy of capillary malformations of the skin. These circumscribed, non-elevated, red and sharply demarcated skin areas are treated with laser when they are esthetically and psychosocially detrimental because of their location (e.g., face, neck, décolleté, hands, fingers). This is usually done with pulsed dye laser (PDL), more rarely with multiplex lasers or IPL (Intense Pulsed Light) with different wavelengths under local cooling. In fact, good fading of the capillary malformation is achieved in many cases. However, despite multiple interventions, complete disappearance is achieved in only about 20% of patients.
Laser therapy for infantile hemangiomas used to be widespread but, in the era of drug therapy with propranolol, it has completely been sidelined. However, laser therapy of cutaneous hemangioma residues may still be an indication today; teleangiectasias in particular respond well here. Particular attention should be paid to the potential worsening of any pre-existing skin atrophy.
Small cutaneous lymphatic vesicles, lymphangioma circumscriptum, especially with accompanying lymphatic leakage (lymphorrhea), can be a good indication for CO2 laser treatment. This leads to complete thermal ablation of the upper skin layers. It often results in initial sealing of the lymph flow from the skin and the formation of a skin scar. Unfortunately, local recurrences are also relatively common.
The use of interstitial laser therapy (usually Nd:YAG) still proves successful today in submucosal venous malformations and more rarely lymphatic malformations (e.g., urinary bladder, urethra, vaginal, rectum, sigmoid colon). It is also used for slow-flow malformations of the pleura, e.g., in conditions following hemorrhage. In addition, there are indications in the hypopharynx, larynx, and trachea in cases of obstruction of the upper airways due to vascular malformation components. However, the latter applications require special expertise.
The treatment of arteriovenous malformations is not a domain of laser therapy.
In fact, the results of laser therapy are very dependent on the type, extent and location of the lesion and the risk-benefit ratio of available treatment alternatives. The more superficial, thin, and circumscribed a lesion is, the more amenable it is to laser therapy. Thus cutaneous capillary malformations will be treated with laser when indicated.
Conversely, deeply situated lesions are difficult to access for laser therapy. In this case interstitial application is necessary. As yet there are no direct scientific data comparing interstitially applied laser therapy with sclerotherapy, a competing technique that is currently more frequently applied. Therefore no definitive statement on comparative effectiveness can be made here.
If the lesion does not completely regress, sometimes the dot-like application of the laser spots without overlap may result in conspicuous geometric patterns of the skin. As a thermally destructive procedure, circumscribed tissue destruction may also occur. On the skin, these includes localized blisters to wounds, discoloration, pigmentary shifts, localized skin atrophy, and scabbing. In the case of deep, interstitial application, for which a circumscribed volume is heated, nerve injuries, burns and, above all, scarring in the course of treatment have also been described. Recurrences are possible.
Unfortunately, the reimbursement of laser therapy is sometimes questioned by insurance companies.
Overall, laser therapy in the field of vascular anomalies is currently used most frequently for capillary malformations. Between 4 and 6 (up to 10) procedures are usually necessary in such cases. As a rule, these are performed under general anesthesia in children.
Currently, there are only a few experienced centers for laser therapy of vascular anomalies, with correspondingly long waiting lists.