Efficacy and safety of a dual-scan protocol for carbon dioxide laser in the treatment of split-thickness skin graft contraction in a red Duroc pig model

Background:Fractional CO_(2) laser plays an important role in scar management post split-thickness skin graft by loosening the graft contracture and restoring the smoothness of the surface.However,the optimal treatment protocol remains unknown.This study applied a dual-scan protocol to achieve both releasing and ablation of contracted skin graft.We comprehensively describe this treatment method and compare the efficacy and safety between this dual-scan method and the conventional mono-scan mode.Methods:A hypercontracted scar model after split-thickness skin grafting in red Duroc pigs was established.All scars meeting the inclusion criteria were randomly divided into four groups:high fluence–low density(HF–LD),low fluence–high density(LF–HD),combined group and control group.The energy per unit areawas similar in the HF–LD and LF–HD groups.Two laser interventions were performed at a 6-week interval.The efficacy of the treatment was evaluated by objective measures of scar area,release rate,elasticity,thickness and flatness,while the safetywas evaluated based on adverse reactions and melanin index.Collagen structurewas observed histologically.The animals were followed up for a maximum of 126 days after modeling.Results:A total of 28 contracted scars were included,7 in each group.At 18 weeks postoperatively,the HF–LD and the combined groups showed significantly increased scar release rate(p=0.000)and elasticity(p=0.036)and decreased type I/III collagen ratio(p=0.002)compared with the control and LF–HD groups.In terms of flatness,the combined group was significantly better than the HF–LD group for elevations<1mm(p=0.019).No significant skin side effects,pigmentation or scar thickness changes were observed at 18 weeks.Conclusions:Dual-scan protocol could achieve superficial ablation and deep release of contracted split-thickness skin graft in a single treatment,with similar contraction release and texture improvement compared to a single deep scan.Its main advantage is to restore a smoother scar appearance.Adequate laser penetration was necessary for the release of contracted scars.

Vascularized lymph node flaps can survive on venous blood without an arterial inflow:an experimental model describing the dynamics of venous flow using indocyanine green angiography(With video)

Background:Several surgeons have described studies of free-tissue transfers using veins instead of arteries.These innovative microsurgical techniques can offer several advantages,such as an easier dissection during flap harvesting,and represent an alternative during an accidental surgical mistake or development of new surgical procedures.The purpose of this study was to describe and explore different constructs of vascularized lymph node transfer(VLNT)only based on venous blood flow in a mouse model,evaluate their blood flow microcirculation through indocyanine green(ICG)angiography and investigate the lymphatic drainage function and the lymph nodes’structures.Methods:Five types of venous lymph node flaps(LNF)were created and investigated:Types IA,IB,IC,IIA and IIB were developed by ICG intraoperatively(with videos in the article).Seven weeks later,by applying methylene blue,the recanalization of the lymphatic vessels between the LNF and the recipient site was detected.Lymph nodes were collected at the same time and their structures were analyzed by hematoxylin and eosin staining analysis.Results:All of the venous LNFs developed except Type IC.Seven weeks later,methylene blue flowed into Types IA,IB,IIA and IIB from recipient sites.When comparing with arteriovenous lymph node,the medullary sinus was diffusely distributed in venous lymph nodes.The proportion of cells was significantly reduced(p<0.05).The artery diameters were significantly smaller(p<0.05).The veins diameters and lymphatic vessels output in Types IA,IB,IIA and IIB were more dilated(p<0.05).Conclusions:This research demonstrated that Type IA,IB,IIA and IIB venous LNFs can retrogradely receive venous blood supply;they can survive,produce a lymphatic recanalization and integrate with the surrounding tissue,despite lymph node structural changes.Our results will improve the understanding of the survival mechanism of venous LNFs and will help researchers to design new studies or lymphatic models and eventually find an alternative procedure for the surgical treatment of lymphedema.

Pre-expanded bipedicled visor flap:an ideal option for the reconstruction of upper and lower lip defects postburn in Asian males

Background:Reconstruction of upper and lower lip subunits is a complicated and elusive challenge.For patients affected by defects involving upper and lower lip subunits,a technique able to reconstruct both aesthetic units with matched colour,sufficient contours and similar texture would be ideal.In this study,we present our experience with upper and lower lip reconstruction using the pre-expanded bipedicled visor flap.Methods:From January 2014 to January 2017,12 male patients presenting with defects of the upper and lower lip subunits were treated using this surgical technique.After a period of expansion of the scalp flap of over 6 months,the bipedicled visor flap was raised from both the parietal regions and rotated to resurface the defect.Delay and section of the pedicle were then performed.Results:Twelve male patients with postburn scars aged 22 to 48 years(mean:34 years)were successfully treated with no major complications.The donor site was closed primarily in all cases.Subsequent flap debulking and minor revisions were performed under local anaesthesia between 6 and 12 months postoperatively.Conclusions:The pre-expanded bipedicled visor flap provides an effective and reliable option for upper and lower lip reconstruction with excellent colour and texture.It is feasible to achieve these results simultaneously from a single donor site by using a pre-expanded bipedicled visor flap.