the cosmetic rejuvenation market now abounds with various injectable devices including : poly - l - lactic acid ( plla ) , polymethyl - methacrylate , collagens , hyaluronic acids ( ha ) , silicone ( s ) , and calcium hydroxylapatite ( caha ) . the choice of which one to use in practice is physician led , based on facial assessments , product characteristics and the desires of the patient . some of these devices can augment facial volume for long periods of time and are heat - labile , others are permanent . fractionated carbon dioxide ( co2 ) lasers are a new treatment modality for skin resurfacing . this laser therapy is based on the theory of fractional photothermolysis introduced by manstein et al . these lasers have been shown efficacious in treating facial photoaging changes and scars and have an improved safety and recovery profile compared with traditional co2 laser resurfacing . although co2 laser skin resurfacing is widely hailed as a safe and effective treatment modality , morbidity is widely reported as well . furthermore , the patient 's medical history may affect the decision to use laser resurfacing . the objective of the current study is to examine the efficacy and safety of 10,600-nm co2 fractional laser on facial skin with previous volume injections with molecules known to be heat - labile or with molecules contraindicated in previous studies involving continuous co2 laser . v ) having had previous facial volume restoration ( plla , ha , s , fat ) were included . they have been treated with fractional 10,600-nm co2 laser ( fx_lumenis , inc . , santa clara , ca ) and completed their treatment sessions . the volume administered was not known since this injection was not performed in our clinic . however , the purpose of the injection as patients stated was to have volumetric effects , and it was considered to be sub - dermal except for the ha . the indication of the laser therapy , age of the patients , previous facial volume restoration and side effects were all recorded from their medical files . superficial and deep ablations ( active fx and deep fx ) were performed for all the patients . these women have been treated between january 2009 and june 2010 with a single session of co2 followed by 5 days of prophylactic acyclovir administration in all patients and 1 week of topical corticosteroids application over the treated area . objective assessments were made through clinical physician global assessment records and improvement scores records over a period of 2 years , from june 2010 till june 2012 . patients satisfaction rates were also recorded answering 2 questions about satisfaction and effects of laser co2 on facial volume ( especially for people previously injected with volumetric fillers ) . the average energy delivered per session was 125 mj / cm for the active fx treatment , and 15 mj / cm for the deep fx treatment . fourteen patients with average age of 52.14 years ( 10 years ) were included in the study . two patients ( 14.28% ) were treated for acne scars and twelve ( 85.72% ) for photoaging rejuvenation . review of their medical records show that 5 ( 35.7% ) patients had plla injection 6.86 years ( 0.4 ) prior to the laser session . eight ( 57.14% ) patients were injected with ha for more than 0.5 year ( 1.1 years ( 0.6 ) ) prior to the laser session . two ( 14.28% ) patients had fat injection more than 1.4 years previous to the laser session , 2 ( 14.28% ) had silicone injection implanted 6 and 8 years respectively previous to the laser sessions and one ( 7.14% ) patient had facial thread lift 9 years ago . the follow - up results 6 months after the session revealed that one ( 7.14% ) patient had clinical improvement of 76% to 100% , seven ( 50% ) had improvement of 51 - 75% , four ( 28.58% ) had moderate clinical improvement of 26 - 50% and two ( 14.28% ) had no improvement . patients characteristics and results the patient surveys regarding overall satisfaction revealed that 9 of the 14 ( 64.28% ) were very satisfied or satisfied , three ( 21.4% ) were slightly satisfied and two ( 14.28% ) were unsatisfied . side effects included pain during the laser treatment ( 7 patients-50% ) , post - treatment scaling ( 13 patients-92% ) , post - treatment erythema ( 14 patients-100% ) , post - treatment hyperpigmentation ( 2 patients-14.28% ) which spontaneously resolved within a month . the duration of the side effects did not affect the grade of clinical improvement or the degree of satisfaction that the patients recorded . other possible adverse events , including post - therapy blister formation , scarring , hypopigmentation , secondary bacterial infection , and viral infection were not encountered . concerning the previous facial volume restoration , no granulomatous reactions were noted , no facial shape deformation , and no asymmetry were encountered whatever the facial volume injection material was . in this retrospective study , the focus was on the safety and efficacy of fractionated co2 laser on patients with previous facial volume restoration . results prove that plla ( injected more than 6 years previous to the laser session ) , fat injection ( more than 1.4 years ) , facial silicone implants ( implanted 6 and 8 years , respectively , in 2 patients ) , ha ( injected for more than 0.5 year ) , and facial thread ( performed 9 years before laser session ) were all safe and we did not encounter any dissolution of these fillers . no studies are found to answer whether the aggressivity of the laser treatment performed in patients with previous implants ( silicone , fat , hyaluronic acid ) is safe ; and after how many months / years co2 laser treatment can be performed safely . is reflected by depth of penetration of fractional co2 beam that depends upon fluency and pulse characteristic . temperatures in skin exposed to a single pass of a co2 laser reach 100c which is sufficient to cause full - thickness burns and resultant scarring . depth of filler placement and depth of co2 fractional column penetration have relevant interactions : if they coincide , then filler will be  destroyed  by heat . some papers stated that when applying co2 laser to skin , there is heat and inflammation effects up to 300 mm near the skin surface to approximately 150 mm at the deep dermis or deeper . after traditional co2 laser performed on facial skin with previous silicone implant and some articles stated that prior injection with silicone is a relative contraindication to skin resurfacing with a co2 laser  . we think that avoidance of this reaction is possible by usage of a single - pass mode of laser , with great care to avoid overlapping pulses . multiple treatment sessions with minimal penetration are preferable to deeper lasing in a single - treatment episode . however , a recent article reported the case caha nodule resolution in a patient following co2 laser session . an eventual explanation of this problem would be the dissolution of caha particles by the fractional co2 laser by high - temperature vaporization of caha , with localized melting and rehardening into an -calcium orthophosphate structure that displays increased brittleness with easy cracking and fissuring into multiple pieces . concerning clinical improvement and patients  overall satisfaction , they were similar to the results published with same skin type patients in many articles.[912 ] the frequency of side effects ( including pain during the laser treatment , post - treatment scaling , post - treatment erythema , post - treatment hyperpigmentation ) was equivalent to the frequency in patients who had not been subject to facial volume injection.[912 ] in conclusion , 10,600-nm co2 fractional laser treatment seems to be safe when used on facial skin previously treated with volume restoration with plla for more than 6 years , ha for more than 0.5 year , s for more than 6 years , fat for more than 1.4 year . therefore , prospective studies with larger series focusing on many other variables ( skin phototype , injected device type ) are required to achieve better conclusions .
background : fractionated carbon dioxide ( co2 ) lasers are a new treatment modality for skin resurfacing . 
 the cosmetic rejuvenation market abounds with various injectable devices ( poly - l - lactic acid , polymethyl - methacrylate , collagens , hyaluronic acids , silicone ) . 
 the objective of this study is to examine the efficacy and safety of 10,600-nm co2 fractional laser on facial skin with previous volume injections.materials and methods : this is a retrospective study including 14 patients treated with fractional co2 laser and who have had previous facial volume restoration . 
 the indication for the laser therapy , the age of the patients , previous facial volume restoration , and side effects were all recorded from their medical files . 
 objective assessments were made through clinical physician global assessment records and improvement scores records . 
 patients satisfaction rates were also recorded.results:review of medical records of the 14 patients show that five patients had polylactic acid injection prior to the laser session . 
 eight patients had hyaluronic acid injection prior to the laser session . 
 two patients had fat injection , two had silicone injection and one patient had facial thread lift . 
 side effects included pain during the laser treatment , post - treatment scaling , post - treatment erythema , hyperpigmentation which spontaneously resolved within a month . 
 concerning the previous facial volume restoration , no granulomatous reactions were noted , no facial shape deformation and no asymmetry were encountered whatever the facial volume product was.conclusion:co2 fractional laser treatments do not seem to affect facial skin which had previous facial volume restoration with polylactic acid for more than 6 years , hyaluronic acid for more than 0.5 year , silicone for more than 6 years , or fat for more than 1.4 year . 
 prospective larger studies focusing on many other variables ( skin phototype , injected device type ) are required to achieve better conclusions .