ORIGINAL ARTICLE Should open excisions and sutured incisions be treated differently? A review and meta-analysis of animal wound models following low-level laser therapy Peter Gál 1,2,3 & Martin Bjørn Stausholm 4,5 & Ivan Kováč 1,6 & Erik Dosedla 7 & Ján Luczy 8 & František Sabol 8 & Jan Magnus Bjordal 4 Received: 5 February 2018 /Accepted: 23 March 2018 # Springer-Verlag London Ltd., part of Springer Nature 2018 Abstract Although low-level laser therapy (LLLT) was discovered already in the 1960s of the twentieth century, it took almost 40 years to be widely used in clinical dermatology/surgery. It has been demonstrated that LLLT is able to increase collagen production/wound stiffness and/or improve wound contraction. In this review, we investigated whether open and sutured wounds should be treated with different LLLT parameters. A PubMed search was performed to identify controlled studies with LLLTapplied to wounded animals (sutured incisions—tensile strength measurement and open excisions—area measurement). Final score random effects meta-analyses were conducted. Nineteen studies were included. The overall result of the tensile strength analysis (eight studies) was significantly in favor of LLLT (SMD = 1.06, 95% CI 0.66–1.46), and better results were seen with 30–79 mW/cm 2 infrared laser (SMD = 1.44, 95% CI 0.67–2.21) and 139–281 mW/cm 2 red laser (SMD = 1.52, 95% CI 0.54–2.49). The overall result of the wound contraction analysis (11 studies) was significantly in favor of LLLT (SMD = 0.99, 95% CI 0.38–1.59), and the best results were seen with 53–300 mW/cm 2 infrared laser (SMD = 1.18, 95% CI 0.41–1.94) and 25–90 mW/cm 2 red laser (SMD = 1.6, 95% CI 0.27–2.93). Whereas 1–15 mW/ cm 2 red laser had a moderately positive effect on sutured wounds, 2–4 mW/cm 2 red laser did not accelerate healing of open wounds. LLLT appears effective in the treatment of sutured and open wounds. Statistical heterogeneity indicates that the tensile strength development of sutured wounds is more dependent on laser power density compared to the contraction rate of open wounds. Keywords Skin wound . Tissue repair . Regeneration . Low-level laser therapy . Power density Introduction Although low-level laser therapy (LLLT) was discovered al- ready in the 1960s of the twentieth century [1], it took almost 40 years to be widely used in clinical dermatology/surgery [2]. In general, lasers with output powers in the range between 5 and 50 mW delivering doses of 1–4 J/cm 2 have been found to be most effective in stimulating tissue repair [3]. Since a dose Peter Gál and Martin Bjørn Stausholm contributed equally to this work. * Peter Gál galovci@yahoo.com; pgal@vusch.sk * Jan Magnus Bjordal jan.bjordal@uib.no 1 Department of Biomedical Research, East-Slovak Institute of Cardiovascular Diseases, Inc., Ondavská 8, 040 11 Košice, Slovak Republic 2 Department of Pharmacology, Faculty of Medicine, Pavol Jozef Šafárik University, Košice, Slovak Republic 3 Department of Pharmacognosy and Botany, Faculty of Pharmacy, Comenius University, Bratislava, Slovak Republic 4 Physiotherapy Research Group, Department of Global Public Health and Primary Care, University of Bergen, Kalfarveien 31, 5018 Bergen, Norway 5 Physical and Occupational Therapy Research Unit, Bispebjerg and Frederiksberg University Hospital, Copenhagen, Denmark 6 2nd Department of Surgery, Louise Pasteur University Hospital and Pavol Jozef Šafárik University, Košice, Slovak Republic 7 Department of Obstetrics and Gynecology, 1st Private Hospital Kosice-Šaca and Pavol Jozef Šafárik University, Košice-Šaca, Slovak Republic 8 Department of Heart Surgery, East-Slovak Institute of Cardiovascular Diseases, Inc. and Pavol Jozef Šafárik University, Košice, Slovak Republic Lasers in Medical Science https://doi.org/10.1007/s10103-018-2496-7