Can a tissue-engineered skin graft improve healing of lower extremity foot wounds after revascularization?

Skin substitutes as treatment for chronic wounds: current and future directions

Chronic wounds such as diabetic foot ulcers and venous leg ulcers place a significant burden on the healthcare system and in some cases, have 5-year mortality rates comparable to cancer. They negatively impact patients' quality of life due to pain, odor, decreased mobility, and social isolation. Skin substitutes are an advanced therapy recommended for wounds that fail to show decrease in size with standard care. The choice of substitute used should be based on evidence, which often differs based on wound etiology. There are more than 75 skin substitutes currently available, and that number is rising. In this review, we discuss current management and future directions of chronic wounds while providing a review of available randomized control trial data for various skin substitutes.

Should video laryngoscopy or direct laryngoscopy be used for adults undergoing endotracheal intubation in the pre-hospital setting? A critical appraisal of a systematic review

The safety and utility of endotracheal intubation by paramedics in the United Kingdom is a matter of debate. Considering the controversy surrounding the safety of paramedic-performed endotracheal intubation, any interventions that enhance patient safety should be evaluated for implementation based on solid evidence of their effectiveness. A systematic review performed by Hansel and colleagues (2022) sought to assess compare video laryngoscopes against direct laryngoscopes in clinical practice. This commentary aims to critically appraise the methods used within the review by Hansel et al (2022) and expand upon the findings in the context of clinical practice.

Comparison of Skin Substitutes for Acute and Chronic Wound Management

Chronic and acute wounds, such as diabetic foot ulcers and burns, respectively, can be difficult to treat, especially when autologous skin transplantations are unavailable. Skin substitutes can be used as a treatment alternative by providing the structural elements and growth factors necessary for reepithelialization and revascularization from a nonautologous source. As of 2020, there are 76 commercially available skin substitute products; this article provides a review of the relevant literature related to the major categories of skin substitutes available.

Fístula arteriovenosa como tratamento adjunto na revascularização arterial do membro em risco

Acute arterial occlusion remains a major challenge for the vascular surgeon. The therapeutic approach depends mostly upon the severity of the tissue injury and the duration of symptoms. Several techniques are available in the current therapeutic arsenal, however, regardless of the technique chosen, postoperative factors frequently observed, such as poor outflow status, or even low graft flow, can contribute negatively to the outcome of revascularization. We describe a case of acute limb ischemia, in the postoperative period of a femoral-tibial bypass, which was occluded due to outflow limitation and high peripheral vascular resistance. The patient underwent a second tibial revascularization combined with construction of an arteriovenous fistula, followed by forefoot amputation and partial skin graft. An energetic approach to the at-risk limb makes it possible to reduce unfavorable outcomes, such as amputation and death, and accelerates recovery of tissues affected by acute ischemia.

Role of Topical Biological Therapies and Dressings in Healing Ischemic Wounds

Ischemic wounds are the most severe expression of critical limb ischemia (CLI), and they have been defined clinically as an end stage of peripheral arterial disease. Urgent revascularization is a fundamental part for limb salvage in patients with CLI. However, the risk of revascularization should be weighed against the likelihood of success given a patient’s life-threatening comorbidities. Once the condition of arterial insufficiency is revascularized, wound care is an important aspect to promote the wound healing process and infection control. MOIST concept for wound care is a modern systematic treatment for enhanced wound healing process. Currently, advanced biological therapies are emerging in ischemic wound therapies to restore the wound healing process and involve active biological agents to support the wound healing process. We studied and summarized the different types of available topical biological therapies and their mechanisms on the healing process including platelet-derived growth factor, epidermal growth factor, fibroblast growth factor, and vascular endothelial growth factor, platelet-rich plasma, and honey for local wound care of patient with CLI. Our review suggests that topical platelet-derived growth factor, epidermal growth factor, platelet-rich plasma, and honey are available as well as considered in the ischemic wound healing process enhancement through the MOIST concept. In conclusion, biologic wound dressing or topical agent therapy may improve the wound healing process, increase limb salvage, is inexpensive, and provides potential safety with nontoxic low-risk therapy in patients with an ischemic wound. Thus, local wound care by biological dressing should be added in adjuvant treatment for ischemic wound patients. However, further randomized studies are needed to support efficacy and long-term outcomes of these biological dressing in patients with ischemic wound.

Oral mucosa: an alternative epidermic cell source to develop autologous dermal-epidermal substitutes from diabetic subjects

Oral mucosa has been highlighted as a suitable source of epidermal cells due to its intrinsic characteristics such as its higher proliferation rate and its obtainability. Diabetic ulcers have a worldwide prevalence that is variable (1%-11%), meanwhile treatment of this has been proven ineffective. Tissue-engineered skin plays an important role in wound care focusing on strategies such autologous dermal-epidermal substitutes.

Split-thickness skin grafting the high-risk diabetic foot

OBJECTIVE

The application of split-thickness skin grafts (STSGs) to chronic extremity wounds has often been considered undesirable because of the perceived high incidence of failure, especially in neuropathic patients with plantar diabetic foot wounds. The purpose of this study was to evaluate the outcomes of STSG placement in patients with chronic lower extremity wounds.

METHODS

We abstracted data from consecutive patients at our institution from January 2007 through April 2013 who underwent STSG placement by vascular and podiatric surgeons for chronic wounds of the lower limb and foot. Patients were monitored for at least 24 weeks, unless the wounds healed sooner.

RESULTS

There were 94 patients (72% male) in the study group, with a mean age of 61.0 ± 12.8 years. Of these, 66 patients had diabetes, including 13 who were dialysis-dependent; the remaining 28 had other chronic nondiabetic wounds. The average duration of follow-up was 12.0 ± 12.9 months. After STSG placement, 65 (69.1%) experienced complete graft incorporation and healing, and 18 (19.1%) required revision, five (5.3%) of whom ultimately required major limb amputation. There were no differences in healing when wounds in patients with and without diabetes or plantar vs nonplantar wound locations were compared (P > .05). Similar results were observed after adjusting the results for initial wound size. Although dialysis patients had a threefold higher rate of STSG revision (46.2% vs 14.8%; P = .01), the cumulative rate of wound healing as a function of time was independent of end-stage renal disease (P = .83).

CONCLUSIONS

The results of this study suggest that STSG may be an effective method for promotion of wound healing in the management of chronic lower extremity wounds irrespective of wound location and presence of diabetes.

Hydrocolloid dressings for healing diabetic foot ulcers

BACKGROUND

Foot ulcers in people with diabetes are a prevalent and serious global health issue. Wound dressings are regarded as important components of ulcer treatment, with clinicians and patients having many different types to choose from including hydrocolloid dressings. There is a range of different hydrocolloids available including fibrous-hydrocolloid and hydrocolloid (matrix) dressings. A clear and current overview of current evidence is required to facilitate decision-making regarding dressing use.

OBJECTIVES

To compare the effects of hydrocolloid wound dressings with no dressing or alternative dressings on the healing of foot ulcers in people with diabetes.

SEARCH METHODS

For this first update, in April 2013, we searched the following databases the Cochrane Wounds Group Specialised Register; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE; and EBSCO CINAHL. There were no restrictions based on language or date of publication.

SELECTION CRITERIA

Published or unpublished randomised controlled trials (RCTs) that have compared the effects on ulcer healing of hydrocolloid with alternative wound treatments in the treatment of foot ulcers in people with diabetes.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, risk of bias assessment and data extraction.

MAIN RESULTS

We included five studies (535 participants) in the review: these compared hydrocolloids with basic wound contact dressings, foam dressings, alginate dressings and a topical treatment. Meta-analysis of two studies indicated no statistically significant difference in ulcer healing between fibrous-hydrocolloids and basic wound contact dressings: risk ratio 1.01 (95% CI 0.74 to 1.38). One of these studies found that a basic wound contact dressing was more cost-effective than a fibrous-hydrocolloid dressing. One study compared a hydrocolloid-matrix dressing with a foam dressing and found no statistically significant difference in the number of ulcers healed. There was no statistically significant difference in healing between an antimicrobial (silver) fibrous-hydrocolloid dressing and standard alginate dressing; an antimicrobial dressing (iodine-impregnated) and a standard fibrous hydrocolloid dressing or a standard fibrous hydrocolloid dressing and a topical cream containing plant extracts.

AUTHORS' CONCLUSIONS

Currently there is no research evidence to suggest that any type of hydrocolloid wound dressing is more effective in healing diabetic foot ulcers than other types of dressing or a topical cream containing plant extracts. Decision makers may wish to consider aspects such as dressing cost and the wound management properties offered by each dressing type e.g. exudate management.

Hydrogel dressings for healing diabetic foot ulcers

BACKGROUND

Foot ulcers in people with diabetes are a prevalent and serious global health issue. Dressings form a key part of ulcer treatment, with clinicians and patients having many different types to choose from including hydrogel dressings. A clear and current overview of current evidence is required to facilitate decision-making regarding dressing use.

OBJECTIVES

To assess the effects of hydrogel wound dressings compared with alternative dressings or none on the healing of foot ulcers in people with diabetes.

SEARCH METHODS

For this first update, in April 2013, we searched the following databases the Cochrane Wounds Group Specialised Register; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE; and EBSCO CINAHL. There were no restrictions based on language or date of publication.

SELECTION CRITERIA

Published or unpublished randomised controlled trials (RCTs) that have compared the effects on ulcer healing of hydrogel with alternative wound dressings or no dressing in the treatment of foot ulcers in people with diabetes.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, risk of bias assessment and data extraction.

MAIN RESULTS

We included five studies (446 participants) in this review. Meta analysis of three studies comparing hydrogel dressings with basic wound contract dressings found significantly greater healing with hydrogel: risk ratio (RR) 1.80, 95% confidence interval (CI) 1.27 to 2.56. The three pooled studies had different follow-up times (12 weeks, 16 weeks and 20 weeks) and also evaluated ulcers of different severities (grade 3 and 4; grade 2 and grade unspecified). One study compared a hydrogel dressing with larval therapy and found no statistically significant difference in the number of ulcers healed and another found no statistically significant difference in healing between hydrogel and platelet-derived growth factor. There was also no statistically significant difference in number of healed ulcers between two different brands of hydrogel dressing. All included studies were small and at unclear risk of bias and there was some clinical heterogeneity with studies including different ulcer grades. No included studies compared hydrogel with other advanced wound dressings.

AUTHORS' CONCLUSIONS

There is some evidence to suggest that hydrogel dressings are more effective in healing (lower grade) diabetic foot ulcers than basic wound contact dressings however this finding is uncertain due to risk of bias in the original studies. There is currently no research evidence to suggest that hydrogel is more effective than larval therapy or platelet-derived growth factors in healing diabetic foot ulcers, nor that one brand of hydrogel is more effective than another in ulcer healing. No RCTs comparing hydrogel dressings with other advanced dressing types were found.

Alginate dressings for healing diabetic foot ulcers

BACKGROUND

Foot ulcers in people with diabetes mellitus are a common and serious global health issue. Dressings form a key part of ulcer treatment, with clinicians and patients having many different types to choose from including alginate dressings. A clear and current overview of current evidence is required to facilitate decision-making regarding dressing use.

OBJECTIVES

To compare the effects of alginate wound dressings with no wound dressing or alternative dressings on the healing of foot ulcers in people with diabetes mellitus.

SEARCH METHODS

For this first update, in April 2013, we searched the following databases the Cochrane Wounds Group Specialised Register; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE; and EBSCO CINAHL. There were no restrictions based on language or date of publication.

SELECTION CRITERIA

Published or unpublished randomised controlled trials (RCTs) that have compared the effects on ulcer healing of alginate dressings with alternative wound dressings or no dressing in the treatment of foot ulcers in people with diabetes.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, risk of bias assessment and data extraction.

MAIN RESULTS

We included six studies (375 participants) in this review; these compared alginate dressings with basic wound contact dressings, foam dressings and a silver-containing, fibrous-hydrocolloid dressing. Meta analysis of two studies found no statistically significant difference between alginate dressings and basic wound contact dressings: risk ratio (RR) 1.09 (95% CI 0.66 to 1.80). Pooled data from two studies comparing alginate dressings with foam dressings found no statistically significant difference in ulcer healing (RR 0.67, 95% CI 0.41 to 1.08). There was no statistically significant difference in the number of diabetic foot ulcers healed when an anti-microbial (silver) hydrocolloid dressing was compared with a standard alginate dressing (RR 1.40, 95% CI 0.79 to 2.47). All studies had short follow-up times (six to 12 weeks), and small sample sizes.

AUTHORS' CONCLUSIONS

Currently there is no research evidence to suggest that alginate wound dressings are more effective in healing foot ulcers in people with diabetes than other types of dressing however many trials in this field are very small. Decision makers may wish to consider aspects such as dressing cost and the wound management properties offered by each dressing type e.g. exudate management.

Foam dressings for healing diabetic foot ulcers

BACKGROUND

Foot ulcers in people with diabetes are a prevalent and serious global health issue. Dressings form a key part of ulcer treatment, with clinicians and patients having many different types to choose from. A clear and current overview of current evidence is required to facilitate decision-making regarding dressing use.

OBJECTIVES

The review aimed to evaluate the effects of foam wound dressings on the healing of foot ulcers in people with diabetes.

SEARCH METHODS

For this first update we searched the following databases the Cochrane Wounds Group Specialised Register; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE; and EBSCO CINAHL in April 2013. There were no restrictions based on language or date of publication.

SELECTION CRITERIA

Published or unpublished randomised controlled trials (RCTs) that evaluated the effects on ulcer healing of one or more foam wound dressings in the treatment of foot ulcers in people with diabetes.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, risk of bias assessment and data extraction.

MAIN RESULTS

We included six studies (157 participants) in this review. Meta analysis of two studies indicated that foam dressings do not promote the healing of diabetic foot ulcers compared with basic wound contact dressings (RR 2.03, 95%CI 0.91 to 4.55). Pooled data from two studies comparing foam and alginate dressing found no statistically significant difference in ulcer healing (RR 1.50, 95% CI 0.92 to 2.44). There was no statistically significant difference in the number of diabetic foot ulcers healed when foam dressings were compared with hydrocolloid (matrix) dressings. All included studies were small and/or had limited follow-up times.

AUTHORS' CONCLUSIONS

Currently there is no research evidence to suggest that foam wound dressings are more effective in healing foot ulcers in people with diabetes than other types of dressing however all trials in this field are very small. Decision makers may wish to consider aspects such as dressing cost and the wound management properties offered by each dressing type e.g. exudate management.

Skin grafting for venous leg ulcers

BACKGROUND

Venous leg ulceration is a recurrent, chronic, disabling condition. It affects up to one in 100 people at some time in their lives. Standard treatments are simple dressings and compression bandages or stockings. Sometimes, despite treatment, ulcers remain open for months or years. Sometimes skin grafts are used to stimulate healing. These may be taken, or grown into a dressing, from the patient's own uninjured skin (autografts), or applied as a sheet of bioengineered skin grown from donor cells (allograft). Preserved skin from other animals, such as pigs, has also been used (xenografts).

OBJECTIVES

To assess the effect of skin grafts for treating venous leg ulcers.

SEARCH METHODS

For this update we modified the search strategies and conducted searches of The Cochrane Wounds Group Specialised Register (searched 27 July 2012); The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 7); Ovid MEDLINE (2008 to July Week 3 2012); Ovid MEDLINE (In-Process & Other Non-Indexed Citations, July 26, 2012); Ovid EMBASE (2008 to 2012 Week 29); and EBSCO CINAHL (2008 to 26 July 2012). We did not apply date or language restrictions.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of skin grafts in the treatment of venous leg ulcers.

DATA COLLECTION AND ANALYSIS

Two review authors independently undertook data extraction and assessment of study quality.

MAIN RESULTS

For this update of the review, we identified one new trial, bringing the total to 17 trials (1034 participants) - all of which were generally at moderate or high risk of bias. In 12 trials participants also received compression bandaging.Eleven trials compared a graft with standard care in which no graft was used. Two of these trials (102 participants) compared a dressing with an autograft; three trials (80 participants) compared frozen allografts with dressings, and two trials (45 participants) compared fresh allografts with dressings. Two trials (345 participants) compared tissue-engineered skin (bilayer artificial skin) with a dressing. In two trials (97 participants) a single-layer dermal replacement was compared with standard care.Six trials compared alternative skin grafting techniques. The first trial (92 participants) compared autografts with frozen allograft, a second (51 participants) compared a pinch graft (autograft) with porcine dermis (xenograft), the third (110 participants) compared growth-arrested human keratinocytes and fibroblasts with placebo, the fourth (10 participants) compared an autograft delivered on porcine pads with an autograft delivered on porcine gelatin microbeads, the fifth trial (92 participants) compared a meshed graft with a cultured keratinocyte autograft, and the sixth trial (50 participants) compared a frozen keratinocyte allograft with a lyophilised (freeze-dried) keratinocyte allografts.Significantly more ulcers healed when treated with bilayer artificial skin than with dressings. There was insufficient evidence from the other trials to determine whether other types of skin grafting increased the healing of venous ulcers.

AUTHORS' CONCLUSIONS

Bilayer artificial skin, used in conjunction with compression bandaging, increases venous ulcer healing compared with a simple dressing plus compression. Further research is needed to assess whether other forms of skin grafts increase ulcer healing.

Hydrocolloid dressings for healing diabetic foot ulcers

BACKGROUND

Foot ulcers in people with diabetes are a prevalent and serious global health issue. Wound dressings are regarded as important components of ulcer treatment, with clinicians and patients having many different types to choose from including hydrocolloid dressings. There is a range of different hydrocolloids available including fibrous-hydrocolloid and hydrocolloid (matrix) dressings. A clear and current overview of current evidence is required to facilitate decision-making regarding dressing use.

OBJECTIVES

To compare the effects of hydrocolloid wound dressings with no dressing or alternative dressings on the healing of foot ulcers in people with diabetes.

SEARCH METHODS

We searched The Cochrane Wounds Group Specialised Register (searched 4 January 2012); The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 4); Ovid MEDLINE (1950 to December Week 3 2011); Ovid MEDLINE (In-Process & Other Non-Indexed Citations, January 03, 2012); Ovid EMBASE (1980 to 2011 Week 52); and EBSCO CINAHL (1982 to 30 December 2011). There were no restrictions based on language or date of publication.

SELECTION CRITERIA

Published or unpublished randomised controlled trials (RCTs) that have compared the effects on ulcer healing of hydrocolloid with alternative wound dressings or no dressing in the treatment of foot ulcers in people with diabetes.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, risk of bias assessment and data extraction.

MAIN RESULTS

We included four studies (511 participants) in the review: these compared hydrocolloids with basic wound contact dressings, foam dressings and alginate dressings. Meta-analysis of two studies indicated no statistically significant difference in ulcer healing between fibrous-hydrocolloids and basic wound contact dressings: risk ratio 1.01 (95% CI 0.74 to 1.38). One of these studies found that a basic wound contact dressing was more cost-effective than a fibrous-hydrocolloid dressing. One study compared a hydrocolloid-matrix dressing with a foam dressing and found no statistically significant difference in the number of ulcers healed. There was no statistically significant difference in healing between an antimicrobial (silver) fibrous-hydrocolloid dressing and standard alginate dressing; or an antimicrobial dressing (iodine-impregnated) and a standard fibrous hydrocolloid dressing.

AUTHORS' CONCLUSIONS

Currently there is no research evidence to suggest that any type of hydrocolloid wound dressing is more effective in healing diabetic foot ulcers than other types of dressing. Decision makers may wish to consider aspects such as dressing cost and the wound management properties offered by each dressing type e.g. exudate management.

Alginate dressings for healing diabetic foot ulcers

BACKGROUND

Foot ulcers in people with diabetes mellitus are a common and serious global health issue. Dressings form a key part of ulcer treatment, with clinicians and patients having many different types to choose from including alginate dressings. A clear and current overview of current evidence is required to facilitate decision-making regarding dressing use.

OBJECTIVES

To compare the effects of alginate wound dressings with no wound dressing or alternative dressings on the healing of foot ulcers in people with diabetes mellitus.

SEARCH METHODS

We searched The Cochrane Wounds Group Specialised Register (searched 4 January 2012); The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 4); Ovid MEDLINE (1950 to December Week 3 2011); Ovid MEDLINE (In-Process & Other Non-Indexed Citations, January 03, 2012); Ovid EMBASE (1980 to 2011 Week 52); and EBSCO CINAHL (1982 to 30 December 2011). There were no restrictions based on language or date of publication.

SELECTION CRITERIA

Published or unpublished randomised controlled trials (RCTs) that have compared the effects on ulcer healing of alginate dressings with alternative wound dressings or no dressing in the treatment of foot ulcers in people with diabetes.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, risk of bias assessment and data extraction.

MAIN RESULTS

We included six studies (375 participants) in this review; these compared alginate dressings with basic wound contact dressings, foam dressings and a silver-containing, fibrous-hydrocolloid dressing. Meta analysis of two studies found no statistically significant difference between alginate dressings and basic wound contact dressings: risk ratio (RR) 1.09 (95% CI 0.66 to 1.80). Pooled data from two studies comparing alginate dressings with foam dressings found no statistically significant difference in ulcer healing (RR 0.67, 95% CI 0.41 to 1.08). There was no statistically significant difference in the number of diabetic foot ulcers healed when an anti-microbial (silver) hydrocolloid dressing was compared with a standard alginate dressing (RR 1.40, 95% CI 0.79 to 2.47). All studies had short follow-up times (six to 12 weeks), and small sample sizes.

AUTHORS' CONCLUSIONS

Currently there is no research evidence to suggest that alginate wound dressings are more effective in healing foot ulcers in people with diabetes than other types of dressing however many trials in this field are very small. Decision makers may wish to consider aspects such as dressing cost and the wound management properties offered by each dressing type e.g. exudate management.

Foam dressings for healing diabetic foot ulcers

BACKGROUND

Foot ulcers in people with diabetes are a prevalent and serious global health issue. Dressings form a key part of ulcer treatment, with clinicians and patients having many different types to choose from. A clear and current overview of current evidence is required to facilitate decision-making regarding dressing use.

OBJECTIVES

The review aimed to evaluate the effects of foam wound dressings on the healing of foot ulcers in people with diabetes.

SEARCH STRATEGY

We searched the Cochrane Wounds Group Specialised Register (searched 10 June 2011); The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 2); Ovid MEDLINE (1950 to June Week 1 2011); Ovid MEDLINE (In-Process & Other Non-Indexed Citations, 8 June, 2011); Ovid EMBASE (1980 to 2011 Week 22); EBSCO CINAHL (1982 to 3 June 2011). There were no restrictions based on language or date of publication.

SELECTION CRITERIA

Published or unpublished randomised controlled trials (RCTs) that evaluated the effects on ulcer healing of one or more foam wound dressings in the treatment of foot ulcers in people with diabetes.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, risk of bias assessment and data extraction.

MAIN RESULTS

We included six studies (157 participants) in this review. Meta analysis of two studies indicated that foam dressings do not promote the healing of diabetic foot ulcers compared with basic wound contact dressings (RR 2.03, 95%CI 0.91 to 4.55). Pooled data from two studies comparing foam and alginate dressing found no statistically significant difference in ulcer healing (RR 1.50, 95% CI 0.92 to 2.44). There was no statistically significant difference in the number of diabetic foot ulcers healed when foam dressings were compared with hydrocolloid (matrix) dressings. All included studies were small and/or had limited follow-up times.

AUTHORS' CONCLUSIONS

Currently there is no research evidence to suggest that foam wound dressings are more effective in healing foot ulcers in people with diabetes than other types of dressing however all trials in this field are very small. Decision makers may wish to consider aspects such as dressing cost and the wound management properties offered by each dressing type e.g. exudate management.

Hydrogel dressings for healing diabetic foot ulcers

BACKGROUND

Foot ulcers in people with diabetes are a prevalent and serious global health issue. Dressings form a key part of ulcer treatment, with clinicians and patients having many different types to choose from including hydrogel dressings. A clear and current overview of current evidence is required to facilitate decision-making regarding dressing use.

OBJECTIVES

To assess the effects of hydrogel wound dressings compared with alternative dressings or none on the healing of foot ulcers in people with diabetes.

SEARCH STRATEGY

We searched the Cochrane Wounds Group Specialised Register (searched 10 June 2011); the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 2); Ovid MEDLINE (1950 to June Week 1 2011); Ovid MEDLINE (In-Process & Other Non-Indexed Citations, June 8, 2011); Ovid EMBASE (1980 to 2011 Week 22) and EBSCO CINAHL (1982 to 3 June 2011). There were no restrictions based on language or date of publication.

SELECTION CRITERIA

Published or unpublished randomised controlled trials (RCTs) that have compared the effects on ulcer healing of hydrogel with alternative wound dressings or no dressing in the treatment of foot ulcers in people with diabetes.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, risk of bias assessment and data extraction.

MAIN RESULTS

We included five studies (446 participants) in this review. Meta analysis of three studies comparing hydrogel dressings with basic wound contract dressings found significantly greater healing with hydrogel: risk ratio (RR) 1.80, 95% confidence interval (CI) 1.27 to 2.56. The three pooled studies had different follow-up times (12 weeks, 16 weeks and 20 weeks) and also evaluated ulcers of different severities (grade 3 and 4; grade 2 and grade unspecified). One study compared a hydrogel dressing with larval therapy and found no statistically significant difference in the number of ulcers healed and another found no statistically significant difference in healing between hydrogel and platelet-derived growth factor. There was also no statistically significant difference in number of healed ulcers between two different brands of hydrogel dressing. All included studies were small and at unclear risk of bias and there was some clinical heterogeneity with studies including different ulcer grades. No included studies compared hydrogel with other advanced wound dressings.

AUTHORS' CONCLUSIONS

There is some evidence to suggest that hydrogel dressings are more effective in healing (lower grade) diabetic foot ulcers than basic wound contact dressings however this finding is uncertain due to risk of bias in the original studies. There is currently no research evidence to suggest that hydrogel is more effective than larval therapy or platelet-derived growth factors in healing diabetic foot ulcers, nor that one brand of hydrogel is more effective than another in ulcer healing. No RCTs comparing hydrogel dressings with other advanced dressing types were found.

Skin grafting for venous leg ulcers

BACKGROUND

Venous leg ulceration is a recurrent, chronic, disabling condition. It affects up to one in 100 adults at some time. Standard treatments are simple dressings and compression bandages or stockings. Sometimes, despite treatment, ulcers remain open for months or years. Sometimes skin grafts are used to stimulate healing. These may be taken, or grown into a dressing, from the patient's own uninjured skin (autografts), or applied as a sheet of bioengineered skin grown from donor cells (allograft). Preserved skin from other animals, such as pigs, has also been used (xenografts).

OBJECTIVES

To assess the effect of skin grafts for treating venous leg ulcers.

SEARCH STRATEGY

We searched the Cochrane Wounds Group Specialised Register (February 2006) and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 1, 2006).

SELECTION CRITERIA

Randomised controlled trials (RCTs) of skin grafts in the treatment of venous leg ulcers.

DATA COLLECTION AND ANALYSIS

Two reviewers independently undertook data extraction and assessment of study quality.

MAIN RESULTS

We identified 15 trials - generally of poor methodological quality - involving 768 participants. In 11 trials participants also received compression bandaging. One trial (31 participants) compared a dressing with an autograft. Three trials (74 participants) compared frozen allografts with dressings, and three trials (47 participants) compared fresh allografts with dressings. Two trials (345 participants) compared tissue-engineered skin (bilayer artificial skin) with a dressing. In two trials (71 participants) a single-layer dermal replacement was compared with standard care. Four trials compared skin grafting techniques: one trial (92 participants) compared autografts with frozen allograft, a second (51 participants) compared a pinch graft (autograft) with a porcine dermis (xenograft), the third (seven participants, 12 ulcers) compared tissue-engineered skin with a split-thickness graft, the fourth (10 participants) compared a fresh allograft with a frozen allograft. The trials comparing bilayer artificial skin with a dressing reported a significantly higher proportion of ulcers healing with artificial skin. There was not enough evidence from the other trials to determine whether other types of skin grafting increased the healing of venous ulcers.

AUTHORS' CONCLUSIONS

Bilayer artificial skin, used in conjunction with compression bandaging, increases the chance of healing a venous ulcer compared with compression and a simple dressing. Further research is needed to assess whether other forms of skin grafts increase ulcer healing.

Update on tissue-engineered biological dressings

Tissue-engineered biological dressings offer promise in the treatment of burns, chronic ulcers, donor site and other surgical wounds, and a variety of blistering and desquamating dermatologic conditions. For example, the prevalence of diabetic foot ulcers ranges from 4.4% to 10.5% of diabetics, resulting in 82,000 lower extremity amputations annually; venous leg ulcers affect 0.18% to 1.35% of the population; and pressure ulcers are found in 5.0% to 8.8% of institutionalized patients and 14.8% of patients in acute care facilities. Despite the large number of potential beneficiaries, cellular tissue-engineered products have suffered setbacks in recent years and have garnered considerably lower market share than commercial promoters anticipated. The mechanism of action of these products is not universally agreed upon, but delivery of growth factors and extracellular matrix components to the wound is thought to be important; graft "take" is not usually considered to occur. These "engineered" products do not specifically match a treatment modality to an underlying pathology. Clinical effect is often modest, and sometimes not justi- fiable from a cost-benefit perspective. Nevertheless, clinical reports in the literature of uses of tissueengineered biological dressings continue to mount, indicating that these products are finding niche applications where clinical utility is high and the cost can be defended. Despite commercial setbacks, the first-approved products, Dermagraft, Apligraf, and Cultured Epidermal Autograft (Epicel) are still being marketed, and new ones, such as OrCel, continue to be developed. The major indications for these products are summarized and a brief review of the available clinical literature is offered.

Repair of Experimental Alveolar Bone Defects by Tissue-Engineered Bone

Alveolar bone resorption caused by periodontal diseases remains a difficult clinical problem to treat. Our purpose here was to develop protocols for repairing experimental horizontal alveolar bone defects. The procedure entailed isolating bone marrow stromal cells (BMSC). They were expanded and induced in vitro into osteogenic cells in a defined medium. Induced BMSCs were mixed with calcium alginate to form a gel form of cell-scaffold construct for developing engineered bone. A horizontal alveolar bone defect was created in 15 mongrel dogs, which was 5 mm high on each of two buccal sides at the location of mandibular premolar 3, 4, and molar 1. Without bias, the animals were separated into the following groups: (1) cell-scaffold construct as the experimental group; (2) calcium alginate alone as the control group A; (3) untreated as the control group B. Block sections of the defects were collected at 4, 12, and 24 weeks postsurgery, respectively, and processed for gross and histological observation as well as x-ray examination. The results showed that in vitro induced BMSCs exhibited an osteogenic phenotype. Histologically, bone nodule structure was observed in the tissue of the experimental group at 4 weeks postsurgery and the engineered bone became more mature after 12 weeks, which was similar to normal bone. At 12 weeks postsurgery, the height of repaired alveolar bone reached 2.43 +/- 0.93 mm, 0.98 +/- 0.87 mm, 0.78 +/- 0.75 mm for the experimental group, control groups A and B, respectively, with a significant difference between the experimental and control groups (p < 0.01). The average level of buccal alveolar ridge in experimental group, control groups A and B reached 48.59%, 19.74%, and 15.76% of the height of normal alveolus, respectively, with a significant difference between the experimental group and two control groups (p < 0.01). We thus conclude that BMSCs can be induced to become osteogenic and can be used as seed cells to engineer bone tissue and repair experimental alveolar bone defects.

Dressings and topical agents for surgical wounds healing by secondary intention

BACKGROUND

Many different wound dressings and topical applications are used to cover surgical wounds healing by secondary intention. It is not known whether these dressings heal wounds at different rates.

OBJECTIVES

To assess the effectiveness of dressings and topical agents on surgical wounds healing by secondary intention

SEARCH STRATEGY

We sought relevant trials from the Cochrane Central Register of Controlled Trials, Cochrane Wounds Group Specialised Trials Register, MEDLINE, EMBASE, and CINAHL databases in March 2002.

SELECTION CRITERIA

All randomised controlled trials (RCTs) evaluating the effectiveness of dressings and topical agents for surgical wounds healing by secondary intention.

DATA COLLECTION AND ANALYSIS

Eligibility for inclusion was confirmed by two reviewers who independently judged the methodological quality of the trials according to the Dutch Cochrane Centre list of factors relating to internal and external validity. Two reviewers summarised data from eligible studies using a data extraction sheet, any disagreements were referred to a third reviewer.

MAIN RESULTS

Fourteen reports of 13 RCTs on dressings or topical agents for postoperative wounds healing by secondary intention were identified.

WOUND HEALING

Whilst a single small trial of aloe vera supplementation vs gauze suggests delayed healing with aloe vera, the results of this trial are un interpretable since there was a large differential loss to follow up. A plaster cast applied to an amputation stump accelerated wound healing compared with elastic compression, WMD -25.60 days, 95% CI -49.08 to -2.12 days (1 trial). There were no statistically significant differences in healing for other dressing comparisons (e.g. gauze, foam, alginate; 11 trials). PAIN: Gauze was associated with significantly more pain for patients than other dressings (4 trials). PATIENT SATISFACTION: Patients treated with gauze were less satisfied compared with those receiving alternative dressings (3 trials).

COSTS

Gauze is inexpensive but its use is associated with the use of significantly more nursing time than foam (2 trials). LENGTH OF HOSPITAL STAY: Four trials showed no difference in length of hospital stay. One trial found shorter hospital stay in people after amputation when plaster casts were applied compared with elastic compression (WMD -30.10 days; 95% CI -49.82 to -10.38).

REVIEWERS' CONCLUSIONS

We found only small, poor quality trials; the evidence is therefore insufficient to determine whether the choice of dressing or topical agent affects the healing of surgical wounds healing by secondary intention. Foam is best studied as an alternative for gauze and appears to be preferable as to pain reduction, patient satisfaction and nursing time.

Evaluation of tissue-engineered skin (human skin substitute) and secondary intention healing in the treatment of full thickness wounds after Mohs micrographic or excisional surgery

BACKGROUND

Human Skin Substitute (Apligraf, Organogenesis, Inc., Canton, MA) is a bi-layered tissue-engineered living biological dressing developed from neonatal foreskin. It consists of a bovine collagen matrix containing human fibroblasts with an overlying sheet of stratified human epithelium containing living human keratinocytes. Human Skin Substitute (HSS) appears to be immunologically inert, and has shown usefulness in the treatment of chronic and acute wounds.

OBJECTIVE

Primary objectives were to evaluate the safety and efficacy of HSS in the treatment of full-thickness wounds in a prospective case series. Secondary objectives were to determine the rate of complete wound reepithelialization, incidence of complete wound healing, pain at wound site, overall cosmetic outcome, and patient satisfaction.

METHODS

Fourteen patients were enrolled in the study, of which 12 were evaluable. HSS was applied in a blinded fashion to 6 of the patients immediately following Mohs or excisional surgery for skin cancer. The remaining 6 patients were allowed to heal by secondary intention. Both groups were evaluated at weekly appointments until complete reepithelialization occurred. During each evaluation, wound quality was assessed through the Vancouver Burn Scar Assessment Scale by the investigator and an independent blinded dermatologist. The investigator, blinded observer, and patient further evaluated the cosmetic outcome of the wound through the use of a Visual Analog Scale over a 6-month period.

RESULTS

HSS patients and secondary intention patients were equivalent in comorbid factors such as pain, erythema, edema, exudate, infection, or hematoma between the groups. The incidence of complete wound healing at 6 months was 100% for both groups. Both groups also appeared to heal at similar rates, as defined by the complete reepithelialization of the wound. HSS patients ultimately resulted in more pliable and less vascular wounds as defined by the Vancouver Burn Scar Assessment Scale. Patient satisfaction with cosmetic outcome in both groups was positive at 6 months.

CONCLUSIONS

HSS appears to be a safe, well-tolerated biological dressing with equivalent comorbid factors to secondary intention healing. HSS, however, seems to produce a more pliable and less vascular scar than those developed through healing by secondary intention. HSS also appears to produce more satisfactory cosmetic results when compared to secondary intention healing.

The use of cells in reparative medicine

Cells are the functional elements of reparative medicine and tissue engineering. The use of living cells as a therapy presents several challenges. These include identification of a suitable source, development of adequate methods, and proof of safety and efficacy. We are now well aware that stem or pluripotent cells offer an exciting potential source for a host of functional cell types. Their true potential will only be realized through continued effort to increase basic scientific understanding at all levels, the development of adequate methods to achieve a functional phenotype, and attention to safety issues associated with adequate control of cell localization, proliferation, and differentiation. There is also new understanding regarding the immunology of parenchymal cells and new promising approaches to immune modulation, which will open the door to broader therapies using allogeneic cell sources without prohibitive immune suppression. Control of cell growth and phenotypic expression does not end in the culture vessel, but goes beyond to the patient. A living therapy is not static but dynamic, as is the host response. The cells or tissue construct in most cases will not behave as a whole-organ transplant. It is therefore important that we understand a cell or tissue therapy's ability to react and interact within the host since clinical effectiveness has proven to be one of the most difficult milestones to achieve. A living cell therapy offers great potential to alter the human condition, encompassing alteration of the current biological state of a targeted tissue or organ, augmentation of depleted or lost function, or absolute functional tissue replacement. The extent to which we are able to achieve effective cell therapies will depend on assimilating a rapidly developing base of scientific knowledge with the practical considerations of design, delivery, and host response.