Infantile hemangiomas (IH) are common benign tumors of infancy, most of them resolve during early infancy, some persist and require treatment with systemic propranolol oral solution, which mostly leads to significant improvement. However, in our recent studies we note that some IHs remain with unsatisfactory results 18,19.
In addition, after initial successful propranolol treatment, recurrent IHs occur in up to 25% of treated children. In 10–15% of these patients, repeated treatment with propranolol was required20–30. Furthermore, in rare instances, propranolol can cause side effects such as hypoglycemia, hypotension, bradycardia, diarrhea and hyperkalemia. Therefore, in such cases, there is an unmet need for additional management following the propranolol treatment.
The laser therapy option is especially important in providing additional treatment modalities for residual and recurrent hemangiomas as well as for patients with contraindications or at risk of side effects to propranolol. Numerous studies on PDL treatments have shown response rates of 80–90% 13,14. Given that PDL is characterized by selective absorption by hemoglobin, it can achieve effective photothermolysis of vascular lesions. Yet, the maximum penetration depth of PDL is 0.75–1.2 mm 31. 40–50 % ofIHs extend into the subcutis, emphasizing the need for a deeply penetrating laser, such as Nd:YAG laser (1,064 nm, penetration depth of 5–6 mm) to effectively treat IHs31,32. Additionally, PDL can transform oxyhemoglobin into methemoglobin and lead to thrombus formation32. The absorption of Nd:YAG laser by methemoglobin and thrombi is a further advantage of this laser system. This can enable effective vessel destruction while sparing the surrounding tissues 32.
Two large studies on the combination therapy with PDL and ND: YAG laser for the treatment of IH have been published to date. Saafan and Salah treated 25 patients with IH in the head and neck region and reported that 72% healed completely, 16% healed with mild hyperpigmentation/loss of pigmentation, or “structural skin changes,” and 12% responded inadequately 32. In a retrospective study by Alcántara-González and colleagues, all 22 patients benefited from PDL and Nd:YAG LP laser treatment, irrespective of the stage of IH development 31.
To the best of our knowledge, this is the first published prospective data that studies the treatment of residual hemangioma with Nd:YAG LP laser monotherapy. Out of 30 patients that were enrolled in our study, 28 patients had a great or good response. Along with the physician assessment of treatment success, our study also surveyed the parents asking about their satisfaction.These results suggest high efficacy with a low rate of side effects and are superior to those reported in PDL monotherapy studies 31.
In our study, all patients had minimal, spontaneously resolving side effects after 3 days from the last laser sessions. 6 months following the last sessions, about one third of the patients had loose skin, a quarter had a residual hypopigmented scar and minor cases of residual hyperpigmentation or blister. In other published studies, laser therapy was associated with few side effects; only a small number of patients developed mild atrophy, ulcerations or hyperpigmentation 31,32.
Various cooling systems have been developed to protect the epidermis against thermal damage 33. Application of ice or chilled water may also be used to cool the blood vessels in the upper dermis, however limiting the effects of the laser. Our laser therapy was performed with Zimmer Cryo 6 cold-air chiller device. Cryo 6 decreases the skin temperature quicker and maintains a constant dosage throughout the entire treatment, protecting the epidermis from skin burns. Moreover, it could replace the need for anesthesia, considering many local anesthetics formulas contain sympathomimetic and vasoconstrictors, which may diminish the effectiveness of laser treatment.
Of importance, it was found that one treatment was not enough, a better outcome was reported in patients who had two sessions. However, the third treatment did not give an additional advantage. This suggests that for the majority of patients’ two laser sessions of Nd:YAG LP laser will be sufficient for significant improvement, in comparison to PDL monotherapy for IHs which usually requires more than 5 sessions 13. Thus, treatment with Nd:YAG LP laser reduces the number of necessary treatments, while ensuring an adequate response.
Regarding the factors affecting the response rate, efficacy did not depend upon gender, age, or the depth of the lesion, but was affected by the laser spot size and number of sessions.
The lack of difference in response rates between deep and superficial IHs may be explained by choosing a deeply penetrating laser wavelength (Nd:YAG laser 1064 nm). Laser of larger spot size was associated with better response. Larger spots size has deeper penetration, which is in line with our hypothesis that more better responses to treatment are due to the depth of laser penetration, ie. Nd:YAG laser compared to other laser systems.
In summary, Nd:YAG LP laser therapy (1,064 nm), has been shown to be an effective and safe method for the treatment of IHs, with only 1–2 sessions needed. Our results suggest that Nd:YAG LP laser may be recommended as seconed-line therapy for residual IHs after propranolol treatment, especially for IHs with a deep component.