Current and Future Developments in Wound Healing

Poor wound healing on the face and neck can lead to significant morbidity and dissatisfaction in facial plastic surgery. With current advances in wound healing management and commercially available biologic and tissue-engineered products, there are several options available to optimize acute wound healing and treat delayed or chronic wounds. This article summarizes some of the key principals and recent developments in wound healing research in addition to potential future advancements in the field of soft tissue wound healing.

International validation of a venous leg ulcer risk assessment tool

OBJECTIVE

To internationally validate a tool for predicting the risk of delayed healing of venous leg ulcers (VLUs).

METHOD

A 10-item tool including sociodemographic factors, venous history, ulcer and lower limb characteristics, compression and mobility items to determine the risk of delayed healing of VLUs has previously been developed and validated in Australia. This study prospectively validated this tool using receiver operating characteristic (ROC) methods; using the area under the curve (AUC) to quantify the discriminatory capability of the tool to analyse the international populations of the UK, Austria and New Zealand.

RESULTS

The validation of the tool in the UK, Austria and New Zealand has indicated that the model has moderate discrimination and goodness-of-fit with an AUC of 0.74 (95% CI: 0.66-0.82) for the total risk assessment score.

CONCLUSION

The international validation of a risk assessment tool for delayed healing of VLUs will allow clinicians globally to be able to determine realistic outcomes from an early assessment and to be able to guide early tailored interventions to address the specific modifiable risk factors and thus promote timely healing.

Effect of imatinib on oral wound healing after extraction: A rare case report

BACKGROUND

Proper tissue repair and healing after oral surgery are vital to achieve optimal outcomes. Certain medications may interfere with wound healing, but this debilitating adverse drug reaction is often not reported in the literature. It is unknown whether imatinib (Gleevec; Novartis Pharmaceuticals) interferes with gingival healing after oral surgery.

CASE DESCRIPTION

A 58-year-old man with a dislodged crown and core buildup of tooth no. 19 sought treatment at a prosthodontic clinic. After examination, the patient consented to extraction, ridge preservation, and future implant placement. He had previous surgical resection of a gastrointestinal stromal tumor and was taking 400 mg of imatinib daily. After extraction and ridge preservation, delayed soft-tissue healing and loss of the coronal portion of bone graft were observed at 8 weeks after surgery. Delayed wound healing was observed again after revision surgery. After imatinib therapy was paused, the adverse effect subsided and the wound healed properly. On the basis of causality assessment and clinical judgment, the authors determined that imatinib was the probable cause of this adverse drug reaction. To their best knowledge, this is the first report of delayed gingival healing after oral surgery secondary to imatinib.

PRACTICAL IMPLICATIONS

Dental practitioners should consider the possibility of impaired healing among their patients taking imatinib, especially before procedures that damage gingival tissue, although this adverse drug reaction is not reported in the drug's package insert. Consult with the patient's oncologist is advised before dental manipulations; temporary discontinuation (or dose reductions) of imatinib may be warranted until wounded tissue heals properly.

Biofilm-Innate Immune Interface: Contribution to Chronic Wound Formation

Delayed wound healing can cause significant issues for immobile and ageing individuals as well as those living with co-morbid conditions such as diabetes, cardiovascular disease, and cancer. These delays increase a patient’s risk for infection and, in severe cases, can result in the formation of chronic, non-healing ulcers (e.g., diabetic foot ulcers, surgical site infections, pressure ulcers and venous leg ulcers). Chronic wounds are very difficult and expensive to treat and there is an urgent need to develop more effective therapeutics that restore healing processes. Sustained innate immune activation and inflammation are common features observed across most chronic wound types. However, the factors driving this activation remain incompletely understood. Emerging evidence suggests that the composition and structure of the wound microbiome may play a central role in driving this dysregulated activation but the cellular and molecular mechanisms underlying these processes require further investigation. In this review, we will discuss the current literature on: 1) how bacterial populations and biofilms contribute to chronic wound formation, 2) the role of bacteria and biofilms in driving dysfunctional innate immune responses in chronic wounds, and 3) therapeutics currently available (or underdevelopment) that target bacteria-innate immune interactions to improve healing. We will also discuss potential issues in studying the complexity of immune-biofilm interactions in chronic wounds and explore future areas of investigation for the field.

Vascularization Strategies in the Prevention of Nonunion Formation

Delayed healing and nonunion formation are major challenges in orthopedic surgery, which require the development of novel treatment strategies. Vascularization is considered one of the major prerequisites for successful bone healing, providing an adequate nutrient supply and allowing the infiltration of progenitor cells to the fracture site. Hence, during the last decade, a considerable number of studies have focused on the evaluation of vascularization strategies to prevent or to treat nonunion formation. These involve (1) biophysical applications, (2) systemic pharmacological interventions, and (3) tissue engineering, including sophisticated scaffold materials, local growth factor delivery systems, cell-based techniques, and surgical vascularization approaches. Accumulating evidence indicates that in nonunions, these strategies are indeed capable of improving the process of bone healing. The major challenge for the future will now be the translation of these strategies into clinical practice to make them accessible for the majority of patients. If this succeeds, these vascularization strategies may markedly reduce the incidence of nonunion formation. Impact statement Delayed healing and nonunion formation are a major clinical problem in orthopedic surgery. This review provides an overview of vascularization strategies for the prevention and treatment of nonunions. The successful translation of these strategies in clinical practice is of major importance to achieve adequate bone healing.

[Left posterior auricular Kimura's disease and related literature review: a case report]

SummaryA 43-year-old middle-aged woman admitted by our department was mainly featured by the discovery of the left posterior auricular mass for more than 1 week, and the physical examination was a painless subcutaneous mass. Peripheral eosinophil count was higher than normal, ultrasonic exceed examination showed slightly lower back after the left ear acoustic area with surrounding lymph node enlargement, CT indicated the subcutaneous tumor on the lateral side of the left parotid gland, and the enlarged lymph nodes in the bilateral carotid space, submaxillary space, the left parotid gland space and the posterior cervical space. The pathologic examination indicated lymphoid tissue nodular hyperplasia with lymphoid follicular formation, visible thin-walled blood vessels and the increase in the number of eosinophils in accordance with kimura's disease. Immunohistochemistry results showed: CD3（+）, CD20（+）, CD21 FDC network（+）, CD10 germinal center（+）, bcl-2（-）, bcl-6（-）, CD79a（+）, Lamda（+）, Kappa（+）, ki-67 germinal center（+）. After 4 weeks of operation, part of the scab skin of the incision was detached, with a small incision in the middle segment, about 0.5 cm long. Considering delayed healing of the incision, the patient's incision was restored after 2 weeks of intensive dressing change. No recurrence signs and complications of Kimura's disease were found during the 10-months follow-up.

Intramedullary Metatarsal Fixation for Treatment of Delayed Regenerate Bone in Lengthening of Brachymetatarsia

Delayed regenerate healing after distraction osteogenesis can be a challenging problem for patients and surgeons alike. In the present study, we retrospectively reviewed the data from a cohort of patients with delayed regenerate healing during gradual lengthening treatment of brachymetatarsia. Additionally, we present a novel technique developed by 1 of us (B.M.L.) for the management of delayed regenerate healing. We hypothesized that application of intramedullary metatarsal fixation would safely and effectively promote healing of poor quality, atrophic regenerate during bone lengthening in brachymetatarsia correction. We formulated a study to retrospectively review the data from a cohort of patients with delayed regenerate healing after gradual lengthening for brachymetatarsia. All patients underwent temporary placement of intramedullary fixation after identification of delayed regenerate healing. Patient-related variables and objective measurements were assessed. We identified 10 patients with 13 metatarsals treated with intramedullary fixation for delayed regenerate healing. All 10 patients were female, with 6 (46.2%) right metatarsals and 7 (53.8%) left metatarsals treated. No complications developed with the use of this technique. All subjects progressed to successful consolidation of the regenerate bone at a mean of 44.5 ± 30.2 days after placement of intramedullary metatarsal fixation. No regenerate fracture or reoperations were noted. In conclusion, intramedullary metatarsal fixation is a safe and effective method for managing delayed regenerate healing encountered during distraction osteogenesis correction of brachymetatarsia.

Glucocorticoid-induced delayed fracture healing and impaired bone biomechanical properties in mice

Background

The objective of the study was to investigate the effects of glucocorticoid (GC) on the fracture healing process in a closed femur fracture mice model.

Materials and methods

Forty 12-week-old female CD-1 mice were randomly allocated into four groups: healthy control and mice with prednisone exposure (oral gavage), 6 mg/kg/day (GC-L), 9 mg/kg/day (GC-M) and 12 mg/kg/day (GC-H). Three weeks after the initiation of prednisone dosing, closed femur fractures were created on prednisone-exposed mice and the healthy control. Prednisone administration was continued for 9 weeks post-fracture, and X-ray imaging was performed weekly to monitor the fracture healing process until the mice were euthanized. Necropsy was performed after 9 weeks and the fractured femurs were isolated and processed at necropsy for micro-CT and biomechanical property analysis. Another 20 mice (control and GC-H, 10 mice/group) were used for histology and micro-CT analysis at early time point (2-week post fracture) with continued prednisone exposure.

Results

The results showed that oral administration of prednisone for 3 months in this strain of mice could inhibit endochondral ossification and delay the healing process, especially hard callus formation (woven bone) and bone remodeling during healing. It also could significantly decrease bone biomechanical properties.

Conclusion

Long-term GC administration leads to significantly delayed fracture healing and impaired bone biomechanical properties. This mouse model may be used to systematically study the cellular and molecular mechanisms underlying fracture healing with GC treatment background and may also be used to study the influence of different therapeutic interventions for bone fracture healing.

An unusual presentation of a common condition: Allergic contact dermatitis

Allergic contact dermatitis commonly affects patients with chronic venous leg ulcers and can contribute to impaired wound healing. Many allergens have been identified, and despite the use of advanced dressings, the incidence of allergy has remained high. We discuss an unusual presentation of allergic contact dermatitis in a patient with a chronic wound. The patient's history was consistent with a recurrent venous leg ulcer, but on this occasion, the wound continued to deteriorate despite optimal treatment. This prompted further investigation, which included patch testing. Although the clinical features were not suggestive of allergy, the patch test was positive for several allergens, including Atrauman^® dressings, which the patient was using at the time. This case highlights the importance of regular reassessment and accurate diagnosis for the management of chronic wounds. It also demonstrates that allergic contact dermatitis can contribute to delayed wound healing without causing the classical clinical features of inflammation of the surrounding skin, and even hypoallergenic, non-adherent dressings can be sensitising.

Fixation of proximal pole scaphoid nonunion with non-vascularized cancellous autograft

We present 20 patients with established proximal pole scaphoid nonunions treated with curettage and cancellous autograft from the distal radius and screw fixation. Fractures with significant proximal pole fragmentation were excluded. Patients were treated at a mean of 26 weeks after injury (range 12-72). Union occurred in 18 of 20 patients (90%) based on computed tomographic imaging. The two nonunions that did not heal were treated with repeat curettage and debridement and iliac crest bone grafting without revision of fixation. Union was achieved in both at a mean of 11 weeks after the revision procedures. Our findings suggest that non-vascularized cancellous autograft and antegrade fixation is a useful option for the treatment of proximal pole scaphoid nonunions.

LEVEL OF EVIDENCE

IV.

Predicting delayed healing: The diagnostic accuracy of a venous leg ulcer risk assessment tool

The aim of this study was to validate a newly developed tool that can predict the risk of failure to heal of a venous leg ulcer in 24 weeks. The risk assessment tool was validated, and performance of the tool was assessed using Area Under the Receiver Operating Characteristic Curve (AUC) analysis. Retrospective and prospective validation was conducted through multi-site, longitudinal studies. In the retrospective study (n = 318), 30% of ulcers did not heal within 24 weeks, with the tool demonstrating an AUC of 0.80 (95% CI, 0.68-0.93, P < .001) for the total score. In the prospective study across 10 clinical sites (n = 225), 31% (n = 68) of ulcers did not heal within 24 weeks. Participants were classified with the RAT at enrolment as being at low risk (27%), moderate risk (53%) or high risk (20%) of delayed healing; the proportion of wounds unhealed at 24 weeks was 6%, 29% and 59%, respectively. Validation results of the total score indicated good discrimination and goodness of fit with an AUC of 0.78 (95% CI, 0.71-0.85, P < .001). Validation of this risk assessment tool offers assurance that realistic outcomes can be predicted for patients, and scores can guide early decisions on interventions to address specific risk factors for failing to heal, thus promoting timely healing.

Ulcer area reduction at 2 weeks predicts failure to heal by 24 weeks in the venous leg ulcers of patients living alone

OBJECTIVE

Chronic wounds are costly and affect approximately 1-2% of the population. Venous disease is responsible for about 60% of all chronic leg ulcers and these ulcers can be debilitating, with evidence of a decreased quality of life. Unfortunately, up to 30% of venous leg ulcers (VLUs) fail to heal, despite best practice treatment. This study aimed to identify risk factors associated with delayed healing in participants with VLUs and in particular, whether psychosocial factors play a part in this process.

METHOD

A secondary analysis was conducted of a large data set of clinical, wound healing, health, social, economic and psychological data collected in previous prospective studies of participants with VLUs. Generalised linear mixed modelling was used to identify independent predictors of failure to heal after 24 weeks.

RESULTS

We recruited 247 participants with 318 VLUs from hospital and community settings. Findings revealed that four early predictors were independently significantly associated with failure to heal by 24 weeks. These were: participants who lived alone (OR 2.3, 95%CI [1.13-4.61], p=0.03); had less than 25% reduction in ulcer area within two weeks of treatment (OR 10.07, 95%CI [4.60-22.19], p<0.001); had higher ulcer severity scores (OR 5.1, 95%CI [2.33-11.88], p=0.001); and participants who were not treated with high level compression therapy (i.e.>30 mmHg) at the time of assessment (OR 4.18, 95% CI [1.95-8.97], p=0.002).

CONCLUSION

Identified risk factors offer an opportunity for clinicians to determine realistic outcomes for their patients and to guide decisions on early referral and implementation of tailored adjunctive interventions. Additionally, findings from this study suggest health professionals need to assess and address not only clinical risk factors but also social risk factors, when planning interventions to promote healing.

How do bisphosphonates affect fracture healing?

Bisphosphonates (BPs) have been in use for many years for the treatment of osteoporosis, multiple myeloma, Paget's disease, as well as a variety of other diseases in which there is reduced bone mineral density. Given that bisphosphonates inhibit bone resorption, an important stage of fracture healing; this class of compounds has been widely studied in preclinical models regarding their influence on fracture healing. In animal models, bisphosphonate treatment is associated with a larger fracture callus, coincident with a delay in remodeling from primary woven bone to lamellar bone, but there is no delay in formation of the fracture callus. In humans, de novo use of bisphosphonate therapy after fracture does not appear to have a significant effect on fracture healing. Rarely, patients with long term use of Bisphosphonates may develop an atypical fracture and delay in fracture healing has been observed. In summary, bisphosphonates appear safe for use in the setting of acute fracture management in the upper and lower extremity in humans. While much remains unknown about the effects on healing of long-term bisphosphonates, use prior to "typical" fracture, in the special case of atypical fracture, evidence suggests that bisphosphonates negatively influence healing.

Meta-analytic approaches to determine gender differences for delayed healing in venous leg ulcers

Objective The aim of this analysis was to perform a meta-analysis evaluating gender difference of delayed healing risk in patients with venous leg ulcers. Methods We searched the PubMed and Web of Knowledge from their inception to 4 July 2015. The meta-analysis of pooled odds ratio and 95% confidence interval for venous leg ulcers healing risk were calculated. Results Twelve studies with 4453 patients were included in the meta-analysis. The pooled odds ratio for healing rate stratified by gender was 1.055 (95% CI 0.955-1.165; Z = 1.05, p = 0.292) by fix-effects model. The Begg's test (z = 2.67, p = 0.007), the Egger's test (t = 4.00, p = 0.003), and asymmetric funnel plot suggested there was significant publication bias. Subgroup analysis showed the pooled odds ratios were 1.048 (95% CI 0.945-1.162; Z = 0.88, p = 0.376) in prospective studies and 1.439 (95% CI 0.757-2.736; Z = 1.11, p = 0.266) in retrospective studies. Sensitivity analyses by only pooled adjusted odds ratios showed the pooled odds ratio was 1.049 (95% CI 0.946-1.163; Z = 0.91, p = 0.365), which indicated the results of meta-analysis were robust. Meta-regression analysis showed the healing rate odds ratio stratified by gender was not related with healing rate (t = 0.73, p = 0.484). Conclusion Our meta-analysis indicates that no gender difference existed for delayed healing in venous leg ulcers. Our results may be also useful in developing a risk score for failure of venous leg ulcers to heal.

Biofilm delays wound healing: A review of the evidence

Biofilm is the predominant mode of life for bacteria and today it is implicated in numerous human diseases. A growing body of scientific and clinical evidence now exists regarding the presence of biofilm in wounds. This review summarizes the clinical experiences and in vivo evidence that implicate biofilm in delayed wound healing. The various mechanisms by which biofilm may impede healing are highlighted, including impaired epithelialization and granulation tissue formation, and reduced susceptibilities to antimicrobial agents and host defenses. Strategies to manage biofilm and encourage progression to wound healing are discussed; these include debridement and appropriate antimicrobial therapies which may be improved upon in the future with the emergence of anti-biofilm technologies.

Healing of subtrochanteric atypical fractures after strontium ranelate treatment

Oral bisphosphonates comprise the most widely prescribed class of antiosteoporotic drugs. Recent reports, however, suggest a link between prolonged bisphosphonate use and atypical low-energy, subtrochanteric fractures. We describe the clinical course of two patient treated for a long term with different bisphosphonates who developed subtrochanteric atypical fractures. They were treated initially with intramedullary rodding without pain disappearance or healing of the fracture. Strontium ranelate, a new orally administered agent for the treatment of osteoporosis, was given to these patients with complete closure of the fracture and pain disappearance after a few months. We conclude that based on the chronology of fracture healing and pain disappearance of our patients and published evidence that strontium ranelate can accelerate fracture healing in a rat model, that strontium ranelate had a positive anabolic effect that contributed to fracture healing that produced the secondary disappearance of pain.