The evolution of a clinically relevant experimental model for the realistic evaluation of long-length (80-cm) arterial prostheses

A new carotid-femoral experimental model has been developed which has significant clinical relevance to human limb salvage bypass grafting in the areas of graft length, hemodynamics and tissue environment. More significantly, the graft healing pattern observed with this model is similar to what is seen in humans. Therefore, this experimental model provides a challenging and critical site for dynamic healing studies and comparisons of different types of vascular prostheses.     

Implant site influence on arterial prosthesis healing: A comparative study with a triple implantation model in the same dog

Purpose: The purpose of this study was to develop a cost-effective canine graft healing model that gives information on various implant sites and controls for variable factors between graft locations and between animals and to compare the influence of implant site (retropleural, retroperitoneal, and subcutaneous areas) on arterial graft healing in the same subject under such controlled study conditions.Methods: Five mongrel dogs were studied for 8 weeks, and one was studied for 3 years. Each received three porous Dacron grafts during the same surgery: a carotid-femoral bypass (C-FB) and interposition grafts in the descending thoracic aorta and abdominal aorta. To produce comparable shear stress calibers of the C-FB and abdominal aorta grafts were 2 mm less than those of the descending thoracic aorta, and a distal arteriovenous fistula was created to further increase the C-FB flow. For comparable blood aggregation status platelet aggregation was preevaluated and adjusted with antiplatelet agents. Graft flow surfaces were assessed for thrombus-free surface and endothelial-like cell coverage scores. Tissue samples were studied with hematoxylin-eosin, factor VIII/von Willebrand factor, smooth muscle α-actin staining, and scanning electron microscopy and transmission electron microscopy.Results: All grafts were patent. Shear stress for the three grafts and platelet aggregation among the study subjects were comparable. Healing of descending thoracic aorta and abdomina aorta grafts was similar, but C-FB healing was slow, incomplete, and uneven, with a high incidence of seroma. Eight-week and 3-year results were comparable.Conclusions: This model gives broad healing information about the areas where grafts are often implanted in humans. Eight weeks appears to be a sufficient period to reflect basic and general healing characteristics. Grafts heal better in the retropleural and retroperitoneal areas than in the subcutaneous tissues. (J Vasc Surg 1997;25:528-36.)     

The effect of the multiple arterial grafts compared with single arterial graft for coronary artery bypass grafting on sternal wound complications: A meta-analysis

A meta-analysis investigation was executed to measure the influence of multiple arterial grafts (MAGs) compared with single arterial graft (SAG) for coronary artery bypass grafting (CABG) on sternal wound complications (SWCs). A comprehensive literature inspection till February 2023 was applied and 1048 interrelated investigations were reviewed. The seven chosen investigations enclosed 11 201 individuals with CABG in the chosen investigations' starting point, 4870 of them were using MAGs, and 6331 were using SAG. Odds ratio (OR) in addition to 95% confidence intervals (CIs) were utilised to compute the value of the effect of the MAGs compared with SAG for CABG on SWCs by the dichotomous approaches and a fixed or random model. MAGs had significantly higher SWC (OR, 1.38; 95% CI, 1.10–1.73, P = .005) compared with those with SAG in CABG. MAGs had significantly higher SWC compared with those with SAG in CABG. However, care must be exercised when dealing with its values because of the low number of selected investigations for the meta-analysis.     

A circumferentially elastic arterial prosthesis: three-year studies of a Dacron-Spandex graft in the dog

A circumferentially elastic, compliant arterial prosthesis has been developed consisting of a Dacron-polyether urethane (Spandex) weave. The prosthesis can acutely alter its cross section area after implantation in response to changes in flow and pressure. It shows favorable host incorporation and healing properties when studied after 3 years in the dog thoracic aorta and does not dilate significantly over that time. There is some suggestion that its initially elastic properties, present during the early days after implantation, make it more compliant during this healing period and more adaptable to the actual flow conditions present at the time of its insertion.     

Study of the histologic alterations and viability of the adipose graft in humans

The authors describe a series of sections of adipose autografts in humans, focusing on the histological viability and the alterations observed in a postgraft followup. Five female patients aged 29 to 43 years were subjected to seven grafting sessions prior to a classic abdominoplasty. The autologous adipose tissue was grafted in the infraumbilical region. The grafting intervals were 60, 30, 21, 15, 8, 5, and 2 days before the surgical procedure. The grafted tissue of all groups was surrounded by a collagen capsule. The viable tissue was observed in the peripheral zone approximately 1.5 ± 0.5 mm from the edge of the graft. A loss of approximately 60% of the grafted tissue was still noticed in this viable zone.     

Effect of single-port video-assisted thoracoscopy on surgical site wound infection and healing in patients with lung cancer: A meta-analysis

We performed a meta-analysis to comprehensively assess the effect of single-port video-assisted thoracoscopy on surgical site wound infection and healing in patients with lung cancer. A computerised search for studies on single-port video-assisted thoracoscopy treatment of lung cancer was conducted from the time of database creation through February 2023 using the PubMed, EMBASE, the Cochrane Library, China National Knowledge Infrastructure, and Wanfang databases. Two investigators independently screened the literature, extracted information, and evaluated the quality of studies according to inclusion and exclusion criteria. Either a fixed or random-effects model was used in calculating the relative risk (RR) with 95% confidence intervals (CIs). Meta-analysis was performed using RevMan 5.4 software. The results showed that, compared with multi-port video-assisted thoracoscopy, single-port video-assisted thoracoscopy significantly reduced surgical site wound infection (RR: 0.38, 95% CI: 0.19–0.77, P = .007) and significantly promoted wound healing (RR: 0.37, 95% CI: 0.22–0.64, P < .001). Compared with multi-port video-assisted thoracoscopy, single-port video-assisted thoracoscopy significantly reduced surgical site wound infections and also promoted wound healing. However, because of large variations in study sample sizes, some of the literature reported methods of inferior quality. Additional high-quality studies containing large sample sizes are needed to further validate these results.     

Time dependent variations in biomechanical properties of cadaveric fascia, porcine dermis, porcine small intestine submucosa, polypropylene mesh and autologous fascia in the rabbit model: implications for sling surgery

PURPOSE: We investigated time dependent variations in tensile strength, stiffness, shrinkage and distortion in 6 materials commonly used for transvaginal anti-incontinence surgery. MATERIALS AND METHODS: A total of 15 rabbits were randomized into 3 survival groups (2, 6 and 12 weeks, respectively). Each rabbit had human cadaveric fascia, porcine dermis, porcine small intestine submucosa, polypropylene mesh and autologous fascia implanted on the anterior rectus fascia. At harvest tensiometry and image analysis were performed on each sling. Results were compared to baseline for each sling type and the percent decrease from baseline was compared among sling types. RESULTS: Each type of human cadaveric fascia and porcine allografts showed a marked decrease (60% to 89%) in tensile strength and stiffness from baseline. Polypropylene mesh and autologous fascia did not differ in tensile strength from baseline. Polypropylene mesh increased in stiffness from baseline. Autologous fascia and small intestinal submucosa demonstrated a 41% and 50% decrease in surface area, respectively, at 12 weeks. CONCLUSIONS: To our knowledge the relative contribution of biomechanical properties of sling material to the success of anti-incontinence surgery is unknown. However, rapid loss of tensile strength and stiffness in porcine and cadaveric materials may contribute to the early re-emergence of symptoms following successful sling surgery. The results of this study add scientific validity to the increasing use of synthetics in anti-incontinence surgery. Urologists selecting a sling material should be aware of its time dependent biomechanical fate relative to other sling materials.     

Seasonal impact on surgical site infections and wound healing disturbance in carpal tunnel surgery: A retrospective cohort study

Carpal tunnel syndrome is the most common entrapment syndrome of a peripheral nerve. The gold standard treatment is open carpal tunnel release which has a high success rate, a low complication rate, and predictable postoperative results. However, it has not been analysed yet if there is a seasonal influence on complications for carpal tunnel release, a highly elective procedure. In this retrospective study, we determine whether there is a seasonal impact on surgical site infections (SSI) and wound healing disorders (WHD) in primary carpal tunnel syndrome surgery. Between 2014 and 2018, we have assessed 1385 patients (65% female, 35% male) at a mean age of 61.9 (SD 15.3) years, which underwent open carpal tunnel release because of primary carpal tunnel syndrome. The seasonal data such as the warm season (defined as the period from 1st of June until 15th of September), the average daily and monthly temperature, and the average relative humidity were analysed. Patient demographics were examined including body mass index, alcohol and nicotine abuse, the use of anticoagulants and antiplatelet drugs as well as comorbidities. These data were correlated regarding their influence to the rate of surgical site infections and wound healing disorders in our study collective. A postoperative SSI rate of 2.4% and a WHD rate of 7% were detected. Our data confirms the warm season, the average monthly temperature, and male sex as risk factors for increasing rates of WHDs. Serious SSIs with subsequent revision surgery could be correlated with higher age and higher relative humidity. However there is no seasonal impact on SSIs. We therefore advise considering the timing of this elective surgery with scheduling older male patients preferably during the cold season to prevent postoperative WHDs.     

Bioresources in the pharmacotherapy and healing of burns: A mini-review

The present mini-review actualizes the pharmacy of botanical, animal, and fungal sources of potential value in the management of burns wounds. It also highlights the importance of applying contemporary imaged-based sciences such as radiology in the assessment and prognosis of wounds and burns.     

The clinical use of platelet-rich plasma in the promotion of bone healing: A systematic review

Platelet-rich plasma has been shown in several in vitro and animal studies to play a role in promoting new bone formation. A systematic literature review was conducted to identify the current relevant evidence base, searching across multiple sources including Medline, Embase and the Cochrane Library, and finding five clinically relevant articles. Only one was a randomised controlled trial, but this was underpowered for the outcome measure defined. Three studies exclusively concerned children, and included those with congenital limb deformities. Two other reports were case series. Early clinical results suggest that the use of platelet-rich plasma is safe and feasible, but that at present there is no clinical evidence of benefit in either acute or delayed fracture healing.     

Web creep: the role of infection and delayed healing

Summary Twenty-five digital webs from 21 patients, where web creep was noted after division of simple syndactyly were reviewed. In all cases web creep was related to delayed healing and the average time to its appearance was 8 months.     

Biofilms in wound healing: A bibliometric and visualised study

Bibliometric analyses are often used as a means of visualising the knowledge base and associated trends and patterns in a target scientific field based on a quantitative review of the corresponding literature. In this study, we explore the current status of research pertaining to biofilms in wound healing and elucidate trends in this research space. Through this process, we gain insight into findings from papers indexed in the Web of Science Core Collection. These references were then analysed and plotted using Microsoft Excel 2019, VOSviewer, and CiteSpace V. The results provide a fresh perspective regarding global trends and hotspots in biofilm-related wound healing research. These findings also offer a foundation that researchers can use to identify active hotspots of scientific interest to guide further research endeavours.     

Changes in vein dynamics ranging from low to high pressure levels as a determinant of the differences in vein adaptation to arterial hemodynamic conditions

The causes of the regional differences in venous grafts patency rates are partially understood. Differences in vein dynamics during physiological situations could determine differences in veins' capability to face arterial conditions and could contribute to the dissimilar performance of veins as arterial grafts. In vitro pressure and diameter were measured in four different veins during physiological and arterial (graft) pressure conditions. A diameter-pressure transfer function was designed. Compliance, viscous and inertial properties; circumferential stresses and deformation; and buffering function were calculated. Regional differences in veins' dynamics, but not in buffering function were found during physiological and arterial conditions. The back vein (femoral) showed the least changes when submitted to arterial conditions. Arterial conditions represent different changes in vein dynamics depending on the segment considered. The regional differences in vein dynamics, both at physiological and graft conditions, could contribute to explain the dissimilar results of venous grafts.     

Role of fracture hematoma and periosteum during fracture healing in rats: interaction of fracture hematoma and the periosteum in the initial step of the healing process

To study the mechanisms of fracture healing, we investigated the interaction between fracture hematoma and periosteum during the early phase of fracture healing in rats. Experimentally induced fractures of the tibia in untreated rats were compared histologically with such fractures in rats in which either the bone marrow or the periosteum had been removed. The extent of periosteal cell proliferation and chondrogenesis in the fracture hematoma was evaluated on experimental days 3, 6, 10, and 14. On day 3, periosteal cell proliferation at the tibial fracture site was decreased in the bone marrow-removed rats compared with the proliferation in untreated rats. Little chondrogenesis in the fracture hematoma was seen through day 6 in the periosteum-removed rats. These results suggest that the periosteum is important for mediating the primary steps of chondrogenesis and enchondral ossification in the fracture hematoma and that the fracture hematoma may be essential for periosteal cell proliferation during fracture healing. Received for publication on April 5, 1999; accepted on July 21, 1999     

A Novel Microporous Polyurethane Vascular Graft: In Vivo Evaluation of the UTA Prosthesis Implanted as Infra-Renal Aortic Substitute in Dogs

A novel microporous polyurethane blood conduit developed at the University of Texas at Arlington was implanted as an infra-renal substitute in dogs. The prosthesis was fabricated by precipitating a solution of the polymer with dry nitrogen onto a rotating mandrel. The grafts were sterilized either by gamma radiation (series I) or ethylene oxide (series II); they were implanted for the following prescheduled periods: 4, 24, 48 hours, and J week (short-term) and 2, 4 weeks, 3 and 6 months (medium-term). The thrombohematological characteristics of each animal were evaluated prior to implantation and confirmed that the index of blood coagulability was normal. In the short-term group, five out of eight grafts were patent and three were partially occluded; four grafts in the medium-term group were patent; one was partially occluded; and three were thrombosed at retrieval. One week after implantation, the prostheses were surrounded by an external capsule, which was present mainly at the two anastomoses. The external capsule covered the entire graft at 3 months. No kinking of the grafts was observed and the presence of a mild yellow stain related to bilirubin uptake was detected at 2 weeks, 1, 3, and 6 months. Histological studies have revealed the formation of a thin internal capsule at both anastomoses, 2 weeks postimplantation, which was not anchored to the graft wall. In the medium-term group, the thrombosed grafts failed to develop an internal capsule, whereas the patent graft exhibited a thick internal capsule made of neocollagenous tissue over the entire graft. This new microporous polyurethane prosthesis did not perform satisfactorily as an infra-renal substitute in dogs and its in vivo stability requires further assessment. Thus, the concept of a polyurethane with closed pores does not achieve what was anticipated.     

Full-thickness skin columns: A method to reduce healing time and donor site morbidity in deep partial-thickness burns

The current standard of care for the coverage of large wounds often involves split thickness skin grafts (STSGs) which have numerous limitations. One promising technique that has gained traction is fractional autologous skin grafting using full-thickness skin columns (FTSC). Harvesting occurs orthogonally by taking numerous individual skin columns containing the epidermis down through the dermis and transferring them to the wound bed. The purpose of this porcine study was to investigate the efficacy of implanting FTSCs directly into deep partial-thickness burn wounds, as well as examining donor site healing at the maximal harvest density. It was hypothesised that by utilising FTSCs, the rate of healing in deep partial thickness burns can be improved without incurring the donor morbidity seen in other methods of skin grafting. Deep partial-thickness burns were created on the dorsum of female red duroc swine, debrided 3 days later and FTSCs were implanted at varying expansion ratios directly into the burn wounds. At day 14, 1:50 expansion ratio showed significantly faster re-epithelialisation compared to the debrided burn control and 1:200. Donor sites (at 7%–10% harvest density) were 100% re-epithelialised by day 7. Additionally, the maximal harvest density was determined to be 28% in an ex vivo model, which then five donor sites were harvested at 28% density on a red duroc swine and compared to five STSG donor sites. At maximal harvest density, FTSC donor sites were significantly less hypopigmented compared to STSGs, but no significant differences were observed in re-epithelialisation, contraction, blood flow or dermal thickness. In conclusion, implantation directly into deep partial-thickness burns is a viable option for the application of FTSCs, favouring lower expansion ratios like 1:50 or lower. Little difference in donor site morbidity was observed between FTSC at a maximal harvest density of 28% and STSGs, exceeding the optimal harvest density.     

Management of post-traumatic arterial priapism in children: Presentation of a case and review of the literature

In this article, a 9-year-old boy with arterial priapism is presented. The patient was managed with the conservative measures including imipramine hydrochloride and a favorable outcome was achieved after 2 months of follow-up. The pathophysiology, diagnostic tools and treatment alternatives are discussed.