Histologische Untersuchung zur Auswirkung von Diodenlaserstrahlung auf humanes Fettgewebe in vitro : eine experimentelle Studie zur Laser-assistierten Lipoplastie (LAL)

Abstract

BACKGROUND: Especially plastic surgical operations using flaps for reconstruction tend to require secondary operative corrections to reduce the redundant subcutaneous tissue. Further, adipose tissue accumulations in highly difficult regions of the human body are often a problematic surgical starting point if depending on conventional liposuction techniques. This work investigates the histological effects of fatablation using a high-powered diode laser, operating in the near infrared spectrum.METHODS: For the experiments a total number of n=59 subcutaneous fat samples of the ventro-medial thigh region and the inferior abdominal region of fresh female corpses were used. Irradiation was exclusively carried out with a high-powered diode laser (“Laserline LDF-600 Diode”) operating in the near infrared spectrum of light (808/940 nm). Following the irradiation, the fat samples were histologically stained using a modified trichrome Masson-Goldner technique. Evaluation of the histological slices was performed with a special computer program (DISKUS-Mikroskopische Bilddarstellung; Version 4.25.6). All statistical analyses were performed using the SAS statistical analysis software package, version 9.1 (SAS Institute, Cary, North Carolina, USA) and the S-plus statistical analysis software system, version 6.1 (Insightful Corp., Seattle, Washington, USA). Global significance level for all statistical tests procedures conducted was chosen to alpha=5%.RESULTS: Univariate analyses were carried out using the Pearson correlation coefficient (r). Irradiance (r ranking between -0.2284 and 0.4805) respectively energy density (r ranking between -0.1325 and 0.4911) showed weak to moderate correlation to the 10 response variables. Strongest correlation was found between energy density and collateral damage as well as irradiance and collateral damage. Analysis of covariance (ANCOVA) was used for multivariate analyses with respect to the response variables. Time (p=0.0056), energy density (p=0.0333), irradiance (p=0.0440) percental depth (p<0.0001) demonstrated a statistically significant effect on the observed cavity width. In addition irradiance (p=0.0066) and energy density (p=0.0228) showed a statistically significant effect on the calculated ratio of cavity width and collateral damage (CCD-ratio). Residual analyses showed that the model assumptions were approximately valid in all 10 models. Under consideration of the whole data an irradiance range between 250 and 400 Watt/cm2 could be evaluated. This particular range demonstrated the best results regarding the ratio of cavity width and collateral damage (CCD-ratio). These findings were obtained under continuous water irrigation of the sample surface and defocused laser beam.CONCLUSION: The results of the conducted in vitro study of laser-assisted lipoplasty (LAL) show, that a selective and gentle ablation of fatty tissue using a high-powered diode laser is possible