Growth characteristics of human juvenile, adult and murine fibroblasts: a comparison of polymer wound dressings.

OBJECTIVE: Fibroblasts are important for the successful healing of deep wounds. However, the influence exerted by Cuticell, a natural polymer on fibroblasts and by the synthetic polymer, Suprathel, made of poly-L-lactic acid, is not sufficiently characterised. This study compared the survival and growth characteristics of human juvenile and adult dermal fibroblasts as well as murine fibroblast cell line L929, on a natural polymer with those of a synthetic polymer using different culture models. METHOD: Murine, juvenile and adult human fibroblasts were seeded on both the natural and synthetic polymers using statical slide culture or the medium air interface and dynamical rotatory culture. Cell adherence, viability, morphology and actin cytoskeleton architecture were monitored for 1-7 days. Biomaterial permeability was checked with a previously established diffusion chamber. RESULTS: The majority of the murine and adult human fibroblasts survived in slide and rotatory cultures on both wound dressings. The fibroblasts seeded on the synthetic polymer exhibited phenotypically a typical spread shape with multiple cell adhesion sites earlier than those on the natural polymer. The highest survival rates in all tested fibroblast species over the entire observation time were detected in rotatory culture (mean: >70%). Nevertheless, it led to cell-cluster formation on both materials. In the medium air interface culture, few adult fibroblasts adhered and survived until the seventh day of culture on both the natural and synthetic polymers, and no viable juvenile and L929 fibroblasts could be found by day seven. Apart from a significant higher survival rate of L929 in slide culture on the natural polymer compared with the synthetic polymer at the end of the culturing period (p<0.0001), and a higher cell survival of L929 on the natural polymer in medium air interface culture, only minor differences between both materials were evident. This suggested a comparable cytocompatibility of both materials. Permeability testing revealed slightly higher permeance of the natural polymer compared with the synthetic polymer. CONCLUSION: Cell survival rates depended on the culture system and the fibroblast source. Nevertheless, the juvenile skin fibroblasts were the most sensitive. This observation suggests that wound dressings used in treating children should be tested beforehand with juvenile fibroblasts to ensure the dressing does not compromise wound healing. Future experiments should also include the response of compromised fibroblasts, for example, from burn patients.

Impact of Negative Pressure Wound Therapy on Perfusion Dynamics in Free Latissimus Dorsi Muscle Flaps.

Background: Free muscle flaps can develop significant postoperative edema and wound exudation, thereby increasing interstitial pressure and potentially compromising microcirculation. While concerns exist regarding negative pressure wound therapy (NPWT) to compress free flaps and hinder monitoring, recent studies have indicated a reduction in edema and an increase in blood flow. Objective: To compare microcirculation in free latissimus dorsi muscle (LDM) flaps dressed with and without NPWT. Methods: This retrospective cohort study analyzed prospectively collected data of patients who received free LDM flap reconstruction. Patients were separated into two groups according to management with or without NPWT. Microcirculation was evaluated continuously for up to 72 h utilizing laser doppler flowmetry and tissue spectrometry. Results: In total, n = 61 patients (26 females, 35 males) with an average age of 56.90 (17.4) years were included. NPWT was applied in 12 patients, while a regular cotton dressing was used in 49 patients. Overall, no significant differences in the number of minor and major complications were observed between groups. Both groups showed an increase in microvascular flow over the investigated time period. The flow showed higher absolute values in the NPWT group, reaching statistical significance at 12 h post-anastomosis, p = 0.038. There was a tendency for lower rHb values in the NPWT group, without reaching statistical significance. Conclusions: The presented study confirms the increase in microvascular flow after NPWT application. Whilst ensuring continuous free flap monitoring utilizing laser doppler flowmetry and spectrometry, the data further support the safety of NPWT application without risking vascular compromise due to external compression.

Long-Term Functional Outcomes Following Enzymatic Debridement of Deep Hand Burns Using Nexobrid®: A Retrospective Analysis.

Background: For years, surgical debridement with autografting has been considered the standard of care in the treatment of severe burns of the hand. However, in recent years, enzymatic debridement has increasingly been reported as a good alternative, especially for burns of the hand, as it selectively preserves viable tissue. In this study, we aim to evaluate the long-term function of the hand after enzymatic debridement in deep dermal burns. Methods: A retrospective chart review was conducted as well as measurements of subjective and objective outcome measures through physical examination and Disabilities of the Arm, Shoulder, and Hand (DASH), Patient and Observer Scar Assessment Scale (POSAS), and Vancouver Scar Scale (VSS) scores. Results: A total of 32 enzymatically debrided hands of 24 patients were included with a mean age of 42.4 ± 16.8 years and a mean follow-up of 31 months. Postoperatively, 19 of these could be managed conservatively using skin substitutes such as "Suprathel", 13 had to undergo subsequent autografting. The mean DASH score for the entire study population was eight with a mean value of four in the conservatively managed group and fourteen in the autografted group. The mean Patient, Observer POSAS, and VSS values were nineteen, thirteen, and two. A total of 30 cases showed an effortless complete fist closure, and, also in 30 cases, patients attested to be satisfied with the esthetic appearance of the hand on being asked. Conclusions: The descriptive analysis of these results in our study population suggests that the enzymatic debridement of deep burns of the hand, especially combined with subsequent conservative management with skin substitutes, was associated with low long-term hand disability scores at a follow-up of two years.

In vitro evaluation of a synthetic (Biobrane®) and a biopolymer (Epicite) wound dressing with primary human juvenile and adult fibroblasts after different colonization strategies.

BACKGROUND: The three-dimensional [3D] wound dressings Biobrane® and Epicite are used in the wound management. Fibroblasts are important for successful deep wound healing. The direct effect of Biobrane® and Epicite on human fibroblasts, particularly of juvenile individuals, remains unclear. Therefore, this study compared the survival and growth characteristics of juvenile and adult dermal fibroblasts on Biobrane® and Epicite using different culture models. METHOD: Murine (L929), primary juvenile and adult human fibroblasts were seeded on both materials using two dimensional (2D, slide culture) or 3D culture at the medium-air interface and dynamical rotatory culture. Cell adherence, viability, morphology, actin cytoskeleton architecture and DNA content were monitored. Scanning electron microscopy (SEM) analyses could be only performed from Biobrane®. Permeability of both materials were tested. RESULTS: The majority of all tested fibroblasts species survived on both dressings with no significant differences between 1 and 14 days. Juvenile and adult fibroblasts exerted typical fibroblast morphology with spindle-shaped cell bodies on the materials. SEM visualized morphological differences between murine and human fibroblasts on Biobrane®. Juvenile and adult fibroblasts colonized Biobrane® in rotatory culture after 7 days the most. The Biobrane® rotatory culture of L929 and juvenile fibroblasts showed after 7 days the significantly highest DNA amount. No major gender differences could be observed. Biobrane® had a higher permeability than Epicite. CONCLUSION: Both wound dressing can be colonized by fibroblasts suggesting their high cytocompatibility. Fibroblast survival and morphology on Biobrane® and Epicite depended on the culture system and the fibroblast source.

Laser extraction of a trapped infected port catheter in a child using existing experience from pacemaker and ICD lead removal.

A 9-year-old girl presented with systemic infection related to a Port-a-Cath system (PAC); therefore, the urgent removal of the PAC was indicated. However, the catheter was trapped and not extractable by conventional means. Using existing comprehensive experience in the removal of pacemaker and implantable cardioverter defibrillator leads, the entrapped PAC was successfully extracted by laser technique, thus avoiding open heart surgery.

A 3D In Vitro Model for Burn Wounds: Monitoring of Regeneration on the Epidermal Level.

Burns affect millions every year and a model to mimic the pathophysiology of such injuries in detail is required to better understand regeneration. The current gold standard for studying burn wounds are animal models, which are under criticism due to ethical considerations and a limited predictiveness. Here, we present a three-dimensional burn model, based on an open-source model, to monitor wound healing on the epidermal level. Skin equivalents were burned, using a preheated metal cylinder. The healing process was monitored regarding histomorphology, metabolic changes, inflammatory response and reepithelialization for 14 days. During this time, the wound size decreased from 25% to 5% of the model area and the inflammatory response (IL-1ß, IL-6 and IL-8) showed a comparable course to wounding and healing in vivo. Additionally, the topical application of 5% dexpanthenol enhanced tissue morphology and the number of proliferative keratinocytes in the newly formed epidermis, but did not influence the overall reepithelialization rate. In summary, the model showed a comparable healing process to in vivo, and thus, offers the opportunity to better understand the physiology of thermal burn wound healing on the keratinocyte level.

The Impact of a Nanocellulose-Based Wound Dressing in the Management of Thermal Injuries in Children: Results of a Retrospective Evaluation.

The aim of this retrospective study is to evaluate for the first time the impact of a nanocellulose-based wound dressing in the treatment of pediatric patients with both partial- and deep-thickness burns. Usability and effectiveness were defined based on parameters such as frequency of dressing changes under narcosis, duration of hospital stay, onset of complications, need for additional treatments, and follow up scar formation assessment. Fifty-six children who sustained burns in the year 2018 and were treated with a nanocellulose-based wound dressing were included in the trial. The mean stay in hospital was 6.7 days. Patients underwent dressing changes under narcosis 2.4 times on average, and none had wound-associated infection. In all, 82% of the patients were treated only with nanocellulose-based wound dressings, and reepithelialization occurred after ten days. The majority of patients had scars with normal pigmentation (98%), vascularization (91%), height (92%), and pliability (92%). In conclusion, using a nanocellulose-based wound dressing for the treatment of both superficial, partial-thickness and deep, full-thickness burns has several advantages. Compared with the results published in literature on other wound dressings, it requires a moderate number of dressing changes under narcosis and results in short hospital stays. Additionally, it has a low associated infection rate and promotes wound healing.

Evaluation of severely displaced radial neck fractures in children treated with elastic stable intramedullary nailing.

BACKGROUND: We performed a retrospective case study of 28 consecutive severely displaced radial neck fractures (Judet types III and IV) in children treated with elastic stable intramedullary nailing using the Metaizeau technique. METHODS: We reviewed all preoperative radiographs and classified the injuries according to Judet. All patients were asked to return for later assessment. They underwent physical examination; radiographs were taken; and they were asked for subjective assessment. An evaluation of clinical results was performed using the Mayo Elbow Performance Score (MEPS). RESULTS: According to Judet classification there were 13 type III and 15 type IV fractures. Using the MEPS, excellent results were achieved in 23 cases (82%) and good results in 5 cases (18%). The average MEPS was 97 points. Five patients complained of mild pain. Three malunions were observed. CONCLUSIONS: Elastic stable intramedullary nailing is a minimally invasive technique, allowing stable fixation and providing excellent to good outcomes with a low complication rate. LEVEL OF EVIDENCE: We performed a retrospective level 4 study of case series.

Harmonic US imaging of appendicitis in children.

BACKGROUND: Harmonic imaging (HI), a relatively new ultrasound modality, was initially reported to be of use only in obese adult patients. HI increases the contrast and spatial resolution resulting in artefact-free images, and has been shown in adults to significantly improve abdominal sonography. Regarding its application in paediatric patients, just a handful reports exist and these do not encompass its use in intestinal sonography. OBJECTIVE: To compare the sonomorphological image quality of HI and fundamental imaging (FI, conventional grey-scale imaging) in the diagnosis of histologically confirmed appendicitis in children. MATERIALS AND METHODS: For this prospective comparative study, 50 children (male/female 25/25; mean age 9.9 years) suspected of having appendicitis were recruited. In all patients US examination of the appendix and periappendiceal region was performed preoperatively and appendectomy carried out. The final diagnosis was based on histological examination of the appendix. Both FI and HI were used in the US examination (tissue harmonic imaging, THI; Sonoline Elegra, Siemens; 7.5 MHz linear transducer). A detailed comparison of the images from FI and HI was performed using a scoring system. The parameters compared included delineation of the appendiceal contour, wall, mucosa, contents of the appendix and surrounding tissues. Furthermore, periappendiceal findings such as mesenteric echogenicity, free fluid, lymph nodes and adjacent bowel wall thickening were compared. RESULTS: In 43 children (86%) acute appendicitis was histologically confirmed. The inflamed appendix could be depicted in the HI and FI modes in 93% and 86%, respectively. HI was found to be significantly better for the depiction of the outer contour, wall, mucosa and contents of the appendix (P<0.01). This was also true for the demonstration of free fluid, mesenteric lymph nodes, adjacent bowel walls and mesenteric echogenicity. CONCLUSION: HI should be the preferred modality for scanning the right lower abdomen in suspected acute appendicitis. The diagnosis of acute appendicitis can then be more definitely ascertained.