Tensile strength of adhesives in peripheral nerve anastomoses: an in vitro biomechanical evaluation of four different neurorrhaphies.

BACKGROUND: The fundamental prerequisite for prognostically favorable postoperative results of peripheral nerve repair is stable neurorrhaphy without interruption and gap formation. METHODS: This study evaluates 60 neurorrhaphies on femoral chicken nerves in terms of the procedure and the biomechanical properties. Sutured neurorrhaphies (n = 15) served as control and three sutureless adhesive-based nerve repair techniques: Fibrin glue (n = 15), Histoacryl glue (n = 15), and the novel polyurethane adhesive VIVO (n = 15). Tensile and elongation tests of neurorrhaphies were performed on a tensile testing machine at a displacement rate of 20 mm/min until failure. The maximum tensile force and elongation were recorded. RESULTS: All adhesive-based neurorrhaphies were significant faster in preparation compared to sutured anastomoses (p < 0.001). Neurorrhaphies by sutured (102.8 [cN]; p < 0.001), Histoacryl (91.5 [cN]; p < 0.001) and VIVO (45.47 [cN]; p < 0.05) withstood significant higher longitudinal tensile forces compared to fibrin glue (10.55 [cN]). VIVO, with △L/L0 of 6.96 [%], showed significantly higher elongation (p < 0.001) compared to neurorrhaphy using fibrin glue. CONCLUSION: Within the limitations of an in vitro study the adhesive-based neurorrhaphy technique with VIVO and Histoacryl have the biomechanical potential to offer alternatives to sutured neuroanastomosis because of their stability, and faster handling. Further in vivo studies are required to evaluate functional outcomes and confirm safety.

Impact of age on microvascular free flap perfusion in head and neck reconstruction.

OBJECTIVE: Aging is associated with structural and functional cardiovascular changes that may affect microvascular free flap perfusion, which is a prerequisite for flap viability and flap success. This study is aimed to investigate the impact of age on flap perfusion. STUDY DESIGN: Intraoperative and postoperative flap perfusion of 348 patients who underwent successful reconstruction with a radial free forearm flap (RFFF), anterolateral thigh flap (ALTF), or fibular free flap (FFF) was retrospectively analyzed and compared between older (>70 years) and younger patients (≤70 years) using the Mann-Whitney test and linear regression models. RESULTS: Intraoperative flap blood flow and hemoglobin concentration (55.5 arbitrary units [AU] vs 69.3 AU, P = .004; 42.5 AU vs 47.3 AU, P = .016, respectively) were reduced in ALTFs in older patients compared with younger patients. These 2 differences did not persist in multivariable testing (P = .097 and P = .323, respectively). No other differences were observed between the older and younger patients in terms of intraoperative and postoperative flap blood flow, hemoglobin concentration, and hemoglobin oxygen saturation in RFFFs, ALTFs, and FFFs (all P > .05). CONCLUSIONS: Age has no impact on microvascular free flap perfusion in RFFFs, ALTFs, and FFFs. This could contribute to the observed equal success of free flaps in older patients.

Risk factors associated with onset of medication-related osteonecrosis of the jaw in patients treated with denosumab.

OBJECTIVES: While risk factors of bisphosphonate (BP) associated osteonecrosis of the jaw have been properly analyzed, studies focusing on risk factors associated with denosumab (DNO) are sparse. The purpose of this study was to identify risk factors influencing the onset of medication-related osteonecrosis of the jaw (MRONJ) in patients receiving antiresorptive treatment (ART) with DNO by comparing patients suffering from MRONJ and patients without MRONJ. Multiple variables were evaluated including the impact of a previous BP intake. MATERIALS AND METHODS: A retrospective single-center cohort study with patients receiving DNO was conducted. One-hundred twenty-eight patients were included and divided into three groups: I (control, n = 40) receiving DNO with absence of MRONJ; group II (Test 1, n = 46), receiving DNO with presence of MRONJ; and group III (Test 2, n = 42) sequentially receiving BP and DNO with presence of MRONJ. Patients' medical history, focusing on the identification of MRONJ risk factors, was collected and evaluated. Parameters were sex, age, smoking habit, alcohol consumption, underlying disease (cancer type, osteoporosis), internal diseases, additional chemo/hormonal therapy, oral inflammation, and trauma. RESULTS: The following risk factors were identified to increase MRONJ onset significantly in patients treated with DNO: chemo/hormonal therapy (p = 0.02), DNO dosage (p < 0.01), breast cancer (p = 0.03), intake of corticosteroids (p = 0.04), hypertension (p = 0.02), diabetes mellitus (p = 0.04), periodontal disease (p = 0.03), apical ostitis (p = 0.02), and denture use (p = 0.02). A medication switch did not affect MRONJ development (p = 0.86). CONCLUSIONS: Malignant diseases, additional chemotherapy, DNO dosage, and oral inflammations as well as diabetes mellitus and hypertension influence MRONJ onset in patients treated with DNO significantly. CLINICAL RELEVANCE: Patients receiving ART with DNO featuring aforementioned risk factors have a higher risk of MRONJ onset. These patients need a sound and regular prophylaxis in order to prevent the onset of MRONJ under DNO treatment.

Molecular effects of photon irradiation and subsequent aftercare treatment with dexpanthenol-containing ointment or liquid in 3D models of human skin and non-keratinized oral mucosa.

This study aimed to investigate the molecular effects of radiation and subsequent aftercare treatment with dexpanthenol-containing ointment and liquid on established full-thickness 3D skin models depicting acute radiodermatitis and mucositis. To mimic radiomucositis and radiodermatitis, non-keratinized mucous membrane and normal human skin models were irradiated with 5 Gray. Afterwards, models were treated topically every second day with dexpanthenol-containing ointment or liquid in comparison with placebo and untreated controls. On day 7 after irradiation, histological examination showed impairments in irradiated models. In contrast, models treated with dexpanthenol-containing ointment or liquid showed a completely restored epidermal part. While gene expression profiling revealed an induction of genes related to a pro-inflammatory milieu, oxidative stress and an impaired epidermal differentiation after irradiation of the models, aftercare treatment with dexpanthenol-containing ointment or liquid revealed anti-oxidative and anti-inflammatory effects and had a positive effect on epidermal differentiation and structures important for physical and antimicrobial barrier function. Our findings confirm the potential of our established models as in vitro tools for the replacement of pharmacological in vivo studies regarding radiation-induced skin injuries and give indications of the positive effects of dexpanthenol-containing externals after radiation treatments as part of supportive tumor treatment.

Objective computerised assessment of residual ridge resorption in the human maxilla and maxillary sinus pneumatisation.

OBJECTIVES: Atrophic resorption of the maxillary alveolar ridge is a complication that makes implantological rehabilitation critical. Our aim was to develop a novel computer aided procedure for the accurate quantitative assessment of maxillary residual ridge resorption including pneumatisation of the maxillary sinus that goes beyond previously described approaches and to apply it to a large dataset. MATERIALS AND METHODS: To develop and refine the method, we performed a retrospective analysis using computed tomography data from 405 patients to generate segmented, three-dimensional models of zygomaticomaxillary bones and maxillary sinuses. Using anatomical landmarks and orientation lines or planes, all models were aligned automatically to subsequently generate cross-sectional images (n = 2835), enabling the classification of atrophy as well as the quantification of volumes and caudal extensions of the maxillary sinuses. RESULTS: We developed and implemented an accurate and reproducible workflow for the semi-automated analysis of volumetric maxillary images. Comprehensive statistical analysis of the large quantitative dataset revealed various correlations of maxillary process heights and sinus volumes with atrophy class, age and region and identified conjectural trends over the patient group. CONCLUSIONS: The method was used successfully to process a large dataset to classify atrophy, to measure alveolar height parameters, and to quantify maxillary sinus volume, bottom volume and pneumatisation. CLINICAL RELEVANCE: Apart from the anthropometric value of the generated dataset, the method could be applied to provide additional and more accurate data to assess the necessity of bone augmentation in the context of three-dimensional planning before implantation.

Novel Human Full-Thickness Three-Dimensional Nonkeratinized Mucous Membrane Model for Pharmacological Studies in Wound Healing.

INTRODUCTION: Efforts are increasingly aiming to develop in vitro models that can provide effective alternatives to in vivo experiments. The main aim of this study was the establishment of an in vitro model of the nonkeratinized mucous membrane that can be used as a standardized tool to evaluate biological and therapeutic effects of pharmaceuticals for mucosal wound healing. METHODS: We established a full-thickness in vitro model of the nonkeratinized mucous membrane. While histological examination was performed to assess morphological characteristics, we utilized gene expression profiling using microarray and qRT-PCR analyses to identify molecular effects of treatment with a dexpanthenol-containing ointment after laser wounding. RESULTS: Performing histological and immunofluorescence analyses we proved that our model mimics the two distinctive layers of the mucous membrane - the stratified squamous epithelium and the lamina propria. We used this model to investigate molecular effects of a dexpanthenol-containing ointment that is commonly used for the wound treatment of mucous membranes. For that purpose, our model exhibits a unique feature in that dexpanthenol and proliferation-enhancing additives that may interfere with our studies are not required for the maintenance of the model culture. After setting standardized lesions with a nonsequential fractional ultrapulsed CO2 laser, topical treatment with the dexpanthenol-containing ointment enhanced wound closure in the model compared to placebo and untreated controls. Furthermore, microarray analysis revealed that the treatment of the laser-wounded model with the dexpanthenol-containing ointment evoked an upregulated expression of various genes related to accelerated wound healing. CONCLUSION: Overall, we verified that this novel mucous membrane model can be utilized in future to monitor ex vivo effects of various topical therapies on mucosa morphology, physiology, and gene expression. Our findings confirm the potential of the model as an in vitro tool for the replacement of pharmacological in vivo studies regarding mucosal wound healing.

Accelerated wound healing with a dexpanthenol-containing ointment after fractional ablative CO2 laser resurfacing of photo-damaged skin in a randomized prospective clinical trial.

Background: Laser therapy with an ablative CO2 laser is a prominent treatment option for photo-damaged skin. The healing process and therefore the success of a laser can be supported by an appropriate postoperative treatment of the laser-treated skin. Objective: The effect of a dexpanthenol-containing ointment with petroleum jelly on wound healing after fractional ablative CO2 laser therapy of photo-damaged skin. Methods: A total of 38 patients with photo-damaged skin received fractional ablative CO2 laser treatment. Occlusive wound care was conducted for a period of 7 days. The complete wound area was divided into two sections: one that was treated with a dexpanthenol-containing ointment and a section that was treated with petroleum jelly. This study had three primary outcome measures: (1) Overview images as well as dermatoscopic images of the laser treated skin were taken immediately after laser treatment and on days 1, 2, 5 and 14 (study visits). Dermatoscopic images were analysed to determine changes of the diameter of the individual lesions between the study visits. (2) Wound-healing rate was visually assessed, based on the measure of re-epithelialization. (3) Cosmetic results were evaluated during study visits by patients and physicians applying a visual analogue scale (VAS). Results: Measuring the diameter of laser-generated lesions revealed a significantly faster cure of the lesions in wound sections that were treated with the dexpanthenol-containing ointment on days 1 and 2, in comparison to the lesions that were treated with petroleum jelly. Concordantly, visual evaluation of the wounds revealed significantly better cosmetic results and re-epithelialization on days 1, 2 and 5 after laser treatment in wound sites that were treated with the dexpanthenol-containing ointment. All patients exhibited a completed wound healing on day 14 after laser treatment. Conclusion: In this comparative study, post-operative treatment of laser-treated skin with a dexpanthenol-containing ointment led to a significantly faster wound closure in comparison to petroleum jelly, especially during the early phase of wound healing. Moreover, assessment of the cosmetic result exhibited beneficial effects of the dexpanthenol-containing ointment in the post-operative wound care after laser treatment. These results emphasize that the use of a dexpanthenol-containing ointment in the post-operative phase following CO2 laser therapy could be a promising alternative to the routinely used treatment with petroleum jelly.

Introduction of an algorithm for planning of autologous fibular transfer in mandibular reconstruction based on individual bone curvatures.

BACKGROUND: Reconstruction of the mandible with autologous transplants is a challenging task and current computer-aided surgical planning remains cumbersome. Thus, the aim of the present study was to create an automated computational approach for this procedure. METHODS: The developed algorithm is based on curves following characteristic anatomical features. Geometrical data from a physiological mandible and a fibula were used to generate six different defects, and geometrical accordance was investigated to demonstrate the applicability of the method with different reconstruction parameters (n = 309). RESULTS: The method proved to be applicable, it recognized given clinical constraints and the values of accordance could be used to quantify the success of reconstructions. CONCLUSIONS: With the present approach, the complex three-dimensional task of mandibular reconstruction was simplified, and thus it allows implementation in clinical routine. The computational planning that is proposed may be used to design cutting guides or as geometrical input data for real-time navigated surgery.

Role of Swallowing Function of Tracheotomised Patients in Major Head and Neck Cancer Surgery.

INTRODUCTION: Tracheotomy is a frequent procedure in extended head and neck cancer surgery and known to be a risk factor for prolonged hospitalization. The authors hypothesized that the clinical course and delayed decannulation of patients are not only influenced by airway narrowing, but also by a compromised postoperative swallowing function. MATERIAL AND METHODS: The investigators implemented a retrospective cohort study. The sample was composed of a tertiary care center patients who underwent major head and neck cancer surgery, each receiving a tracheostomy. Data collected include general clinical data as well as endoscopical evaluation of swallowing function and aspiration rate. Descriptive and bivariate statistics were computed and the P value was set at.05. RESULTS: The sample was composed of 96 patients with an average age of 64.2 and sex ratio of 1.4:1 (m:f). There was a strong statistically significant relation between swallowing function and timing of decannulation (P < 0.001) and duration of hospitalization (P < 0.001). Age (P = 0.55), sex (P = 0.54), tumor size (P = 0.12), general diseases (P = 0.24), distant metastases (P = 0.15), or extent of neck dissection (P = 0.15) were not significantly associated to swallowing function. Permanent cannulation was significantly correlated to a primary cancer of the soft palate or base of the tonge (P < 0.001). CONCLUSION: The results of this study confirm the importance of the evaluation of swallowing function before the removal of the tracheotomy cannula in head and neck cancer patients.

Classification of the level of mandibular atrophy - A computer-assisted study based on 500 CT scans.

OBJECTIVE: For the optimal treatment of patients with highly atrophic mandibles, it is required to assess and quantify the extent of atrophy. The classification schemes that are well established today are known to be limited with respect to objectivity and reproducibility. Thus, the aim of the study was to generate a computer-aided method of classification, investigate its applicability in comparison with the established methods, and apply it to a large set of data. MATERIALS AND METHODS: Mandibular geometries were segmented from 500 Multislice (MSCT) datasets of atrophic and non-atrophic mandibles and automatically processed to gain virtual images of the mandibular cross-sections. Three different human investigators classified these data according to Cawood and Howell's classification scheme. Additionally, a tailored computer algorithm was applied that could work automatically and thus be observer independent. Furthermore, geometrical properties of the mandibles were investigated, statistically analysed, and correlated to the protocolled dental status and to the human and computer-generated classifications. RESULTS: Whilst the atrophy classification scheme showed highly significant correlation to the local dimensions of the alveolar ridge, its reproducibility was limited. It was shown that the human classifiers could not objectively classify the mandibular atrophy according to the established methods, with only 60.9% of decisions being unequivocal. The computer-aided method showed similar results to the human investigators. CONCLUSION: It is feasible to develop computer-aided procedures for the objective and fully reproducible classification of the level of atrophy. With further research, the established classification scheme may be ameliorated with the aid of computational methods.

Prospective comparison of perioperative antibiotic management protocols in oncological head and neck surgery.

OBJECTIVES: The adequate perioperative antibiotic prophylaxis in head and neck cancer surgery is an important and easy applicable tool to decrease nosocomial morbidity and mortality by reducing the rate of infections. In the study a strictly perioperative antibiosis is compared with an extended postoperative prophylactic antibiosis. We aim to clarify the value of postoperative prophylactic antibiosis for the recovery and clinical course of patients. MATERIAL AND METHODS: In this prospective study 75 consecutive patients, who underwent major oncological head and neck surgery were included and divided in three groups, each containing 25 patients. The first group received peri- and postoperative antibiotic prophylaxis (POAP) from the day of operation until the fifth day postoperatively. The second group was treated with perioperative antibiotic prophylaxis (PEAP) only. The third group received perioperative antibiotic prophylaxis and increased local antiseptic care (PAPAC). General anamnestic data was collected, as well as duration of hospitalisation, stay on intensive care unit, rate and type of infections, surgical closure of the tracheostomy, and postoperative blood parameters. RESULTS: There were no statistically significant differences in general diseases or extent of surgery between the groups. There were statistically significant fewer patients suffering from surgical site infections in subjects with POAP (n = 1) in comparison to PEAP (n = 9; p = 0.011) and PAPAC (n = 9; p = 0.011). In contrast, other nosocomial infections (pneumonia, urinary tract infection, sepsis) did not decrease under a prolonged antibiotic prophylaxis. CONCLUSION: Based on findings of the study, we recommend an extended postoperative antibiotic prophylaxis for patients undergoing major oncological head and neck surgery.

Color duplex ultrasonography versus handheld Doppler to plan anterior lateral thigh flaps.

BACKGROUND: The anterior lateral thigh flap (ALT) has become increasingly important in reconstructive surgery in the head and neck region. To cope with the problem of anatomical variability in the supplying blood vessels, preoperative evaluation is desirable. Purpose of the study is to compare the most commonly used Doppler devices Handheld Doppler (HD) and Color Doppler Ultrasonography (CDU) for their clinical reliability. METHODS: Forty five consecutive head and neck cancer patients (mean age 66.0 ± 11.2 years) were included in the study. They all underwent a reconstruction via ALT flap for a defect in the head and neck area. Study period ranged from May 2014 to August 2015. We preoperatively conducted HD and CDU on the lateral thigh and compared the intraoperative findings by measuring presence of the perforator and distance to the estimated position. RESULTS: There were 95 perforators identified in 45 patients. The sensitivity and positive predictive value (PPV) were calculated as 97.9% and 100% for CDU and 90.5% and 80.4% for HD, respectively. Accuracy was significantly greater with the HD compared to the CDU device (P < 0.001) and was strongly associated with body mass index (BMI) (P < 0.001). This effect was stronger in HD than in CDU (r = 0.800; P < 0.001 versus r = 0.673; P < 0.001). CONCLUSIONS: Our results indicate CDU is more precise and reliable than HD with respect to detecting the anatomical position of perforating arteries. © 2017 Wiley Periodicals, Inc. Microsurgery 37:388-393, 2017.

Planning of mandibular reconstructions based on statistical shape models.

PURPOSE: The reconstruction of large continuity defects of the mandible is a challenging task, especially when the shape of the missing part is not known prior to operation. Today, the surgical planning is based mainly on visual judgment and the individual skills and experience of the surgeons. The objective of the current study was to develop a computer-based method that is capable of proposing a reconstruction shape from a known residual mandible part. METHODS: The volumetric data derived from 60 CT scans of mandibles were used as the basis for the novel numerical procedure. To find a standardized representation of the mandible shapes, a mesh was elaborated that follows the course of anatomical structures with a specially developed topology of quadrilaterals. These standard meshes were transformed with defined mesh modifications toward each individual mandible surface to allow for further statistical evaluations. The data were used to capture the inter-individual shape variations that were considered as random field variations and mathematically evaluated with principal component analysis. With this information of the mandibular shape variations, an algorithm was developed that proposes shapes for reconstruction planning based on given residual mandible geometry parts. RESULTS: The accuracy of the novel method was evaluated on six different virtually defined continuity defects that were each created on three mandibles that were not part of the initial database. Virtual reconstructions showed sufficient accuracy of the algorithm for the planning of surgical reconstructions, with average deviations toward the actual geometry of [Formula: see text] mm for small missing parts and 5 mm for large hemi-lateral defects. CONCLUSIONS: The presented algorithm may be a valuable tool for the planning of mandibular reconstructions. The proposed shapes can be used as templates for computer-aided manufacturing, e.g., with 3D printing devices that use biocompatible materials.

Computational geometry assessment for morphometric analysis of the mandible.

This paper presents a fully automated algorithm for geometry assessment of the mandible. Anatomical landmarks could be reliably detected and distances were statistically evaluated with principal component analysis. The method allows for the first time to generate a mean mandible shape with statistically valid geometrical variations based on a large set of 497 CT-scans of human mandibles. The data may be used in bioengineering for designing novel oral implants, for planning of computer-guided surgery, and for the improvement of biomechanical models, as it is shown that commercially available mandible replicas differ significantly from the mean of the investigated population.

Routine preoperative colour Doppler duplex ultrasound scanning in anterolateral thigh flaps.

The anterolateral thigh flap (ALT) is often used to reconstruct the head and neck and depends on one or more skin perforators, which often present with variable anatomy. The aim of this study was to localise and evaluate the precise position of these perforators preoperatively with colour Doppler duplex ultrasound scanning (US). We detected 74 perforators in 30 patients. The mean duration of examination with colour Doppler was 29 (range 13-51) minutes. Adequate perforators and their anatomical course could be detected preoperatively extremely accurately (p<0.001). The mean difference between the preoperatively marked, and the real, positions was 6.3 (range 0-16) mm. There was a highly significant correlation between the accuracy of the prediction and the body mass index of the patient (0.75; p<0.001). Neither the age nor the sex of the patient correlated with the accuracy of the prediction. Colour Doppler duplex US used preoperatively to localise perforators in ALT flaps is reliable and could be adopted as standard procedure.

Impairment of an atrophic mandible by preparation of the implant cavity: a biomechanical study.

An important complication during insertion of implants in atrophic mandibles is the fracture that can be induced by preparation of the cavity. We designed this study to identify which configuration of cavities in the interforaminal region was the least likely to fracture. An electromechanical testing machine was used to measure breaking loads of specifically-designed synthetic models of atrophic mandibles. The implant cavities correlated with the common clinical patterns. Intact atrophied synthetic mandibles broke at a mean (SD) load of 729.48 (59.94) N (control group). Models with four different configurations of cavities fractured as follows: two short, wide cavities (8 x 4.2mm) at a mean (SD) load of 569.17 (67.7) N; two long, thin cavities (15 x2.8mm) at a load of 563.40 (62.0) N; four short, wide cavities (8 x 4.2mm) at a load of 667.01 (71.89) N; and four long, thin cavities (15 x 2.8mm) at a load of 409.50 (43.61) N. Biomechanical findings showed that there was a greater risk of fracture of atrophic mandibular models in long, thin implant cavities with more preparation sites. Each cavity prepared for an implant increased the risk of fracture in an atrophic mandible. The risk of fracture is greatest with long, thin cavities.

Biomechanical competence of six different bone screws for reconstructive surgery in three different transplants: Fibular, iliac crest, scapular and artificial bone.

The goal of this study was to determine a combination of screw and transplantation type that offers optimal primary stability for reconstructive surgery. Fibular, iliac crest, and scapular transplants were tested along with artificial bone substrate. Six different kinds of bone screws (Medartis(©)) were compared, each type utilized with one of six specimens from human transplants (n = 6). Controlled screw-in-tests were performed and the required torque was protocolled. Subsequently, pull-out-tests were executed to determine the retention forces. The artificial bone substitute material showed significantly higher retention forces than real bone samples. The self-drilling screws achieved the significantly highest retention values in the synthetic bone substitute material. Cancellous screws achieved the highest retention in the fibular transplants, while self-drilling and cancellous screws demonstrated better retention than cortical screws in the iliac crest. In the scapular graft, no significant differences were found between the screw types. In comparison to the human transplant types, the cortical screws showed the significantly highest values in the fibula and the lowest values in the iliac crest. The best retention was found in the combination of cancellous screws with fibular graft (514.8 N + -252.3 N). For the flat bones (i.e., scapular and illiac crest) we recommend the cancellous screws.

Effects of non-ablative fractional erbium glass laser treatment on gene regulation in human three-dimensional skin models.

Clinical experiences with non-ablative fractional erbium glass laser therapy have demonstrated promising results for dermal remodelling and for the indications of striae, surgical scars and acne scars. So far, molecular effects on human skin following treatment with these laser systems have not been elucidated. Our aim was to investigate laser-induced effects on skin morphology and to analyse molecular effects on gene regulation. Therefore, human three-dimensional (3D) organotypic skin models were irradiated with non-ablative fractional erbium glass laser systems enabling qRT-PCR, microarray and histological studies at same and different time points. A decreased mRNA expression of matrix metalloproteinases (MMPs) 3 and 9 was observed 3 days after treatment. MMP3 also remained downregulated on protein level, whereas the expression of other MMPs like MMP9 was recovered or even upregulated 5 days after irradiation. Inflammatory gene regulatory responses measured by the expression of chemokine (C-X-C motif) ligands (CXCL1, 2, 5, 6) and interleukin expression (IL8) were predominantly reduced. Epidermal differentiation markers such as loricrin, filaggrin-1 and filaggrin-2 were upregulated by both tested laser optics, indicating a potential epidermal involvement. These effects were also shown on protein level in the immunofluorescence analysis. This novel standardised laser-treated human 3D skin model proves useful for monitoring time-dependent ex vivo effects of various laser systems on gene expression and human skin morphology. Our study reveals erbium glass laser-induced regulations of MMP and interleukin expression. We speculate that these alterations on gene expression level could play a role for dermal remodelling, anti-inflammatory effects and increased epidermal differentiation. Our finding may have implications for further understanding of the molecular mechanism of erbium glass laser-induced effects on human skin.