PEER-REVIEW | DERMATOLOGY | ablative CO2 laser system is safe and effective for facial


atrophic acne scarring. Scar improvement was noted in the majority of patients with minimal discomfort, minimal downtime, and continued improvement43


. A


study conducted on 64 patients with moderate to severe facial acne scars of four sessions of either a Q-switched 1064 nm Nd:YAG or CO2


supports this further. The fractional CO2 .


laser at a 1 month interval laser showed


significant effect on the improvement of atrophic acne scars, compared with Q-Switched 1064-nm Nd:YAG laser44


In 2013, Mohammed developed a new pinpoint irradiation technique using a CO2


laser for treating


ice pick acne scars. An open label pilot study conducted on 60 patients with ice pick acne scars revealed excellent improvement results, which were non-significantly different from the fractional laser45


by Schweiger and Sundick46


. This was also confirmed ; 90% of 37


patients treated with IPL in combination with fractional CO2


laser significantly improved


and 80% showed excellent response to inflammatory lesions and atrophic scars47


.


Erbium yttrium-aluminum-garnet laser Multiple passes with this laser are necessary to


ablate to a similar depth as one pass of the CO2 laser, and because the Er:YAG effects are


photomechanical instead of photothermal (like the CO2


achieve40, 48-49


Er:YAG/CO2 CO2


), intraoperative haemostasis is difficult to .


Therefore, the short-pulsed Er:YAG laser is limited in its use for moderate-to-severe acne scars. Hybrid laser systems are capable of delivering both energy for coagulation and Er:YAG energy for fine


tissue ablation. The dual mode Er:YAG combines short pulses (for ablation) with longer pulses (for coagulation)50 These lasers have been shown to produce deeper


. 12 months,


and 2.5 (75%) at 18 months. Collagenesis and dermal remodelling were observed histologically on examination of biopsied tissue up to 18 months after session41


. Also, in another


study, 24 subjects received forearm and facial treatments and these were well-tolerated; 83% of subjects exhibited moderate or better overall improvement42


. Qian et al conducted a study with 31 patients (11


women, 20 men, skin types III-IV) with facial acne scarring and treated them with three sequential fractional sessions over a 6-month period. Outcome and global improvement was evaluated blindly with before and after photographs by two physicians 3 and 12 months after the final sessions. Excellent improvement in scars presented in 12.9% of the patients, while 38.71% noted good to fair results. The clinical response at the 12-month follow-up visit tended to be better than at the 3-month follow-up visit, but was not statistically significant43 This high-energy pulsed and cool-scanned fractional


. 28  July/August 2014 | prime-journal.com Devices


targeting P. acnes, causing selective damage to the sebaceous gland and decrease sebum production are short-lived and require continued follow-up treatments; but result in long- term acne clearance.


tissue vapourisation, as well as greater control of haemostasis, and collagen contraction. Overall clinical improvement was achieved in more than 50% of subjects with milder photodamage and scarring (Glogau classes I and II)51-52


.


Non-ablative laser skin resurfacing Recently, focus has shifted towards non-ablative technologies that deliver either laser, light based, or radiofrequency energies to the skin.


Pulsed dye laser Used mainly for the treatment of hypertrophic scars. It has been hypothesised that the selective heating of dermal vessels leads to release of endothelial-derived growth factors and cytokines that up-regulate fibroblasts in treated skin, thereby resulting in neocollagenesis53


.


Mid-infrared lasers Laser systems located in the mid infrared portion of the electromagnetic spectrum, including the 1320 nm Nd:YAG, 1450 nm diode, and 1540 Er:Glass lasers, possess


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