Factors Affecting Wound Healing

Excerpted from, “Worldwide Wound Management, Forecast to 2024: Established and Emerging Products, Technologies and Markets in the Americas, Europe, Asia/Pacific and Rest of World”, Report #S251.

A delicate physiological balance must be maintained during the healing process to ensure timely repair or regeneration of damaged tissue. Wounds may fail to heal or have a greatly increased healing time when unfavorable conditions are allowed to persist. An optimal environment must be provided to support the essential biochemical and cellular activities required for efficient wound healing and to remove or protect the wound from factors that impede the healing process.

Factors affecting wound healing may be considered in one of two categories depending on their source. Extrinsic factors impinge on the patient from the external environment, whereas intrinsic factors directly affect the performance of bodily functions through the patient’s own physiology or condition.

Preparation of the wound bed (WBP) is essential for the support of efficient and effective healing, especially when advanced wound care products are to be used. WBP involves removing localized barriers to healing, such as exudate, dead tissue or infected tissue.

Wound Bed Preparation: the TIME and DIMES acronyms

WBP involves debridement, reduction and neutralization of the bioburden and management of exudate from the wound. The TIME acronym provides a systematic way to manage wounds by looking at each stage of wound healing. The goal is to have the best, thoroughly-vascularized wound bed possible.

TIME stands for:

  • T: Tissue, non-viable or deficient.

The wound care professional should look for non-viable tissue, which includes necrotic tissue, tissue which has sloughed off, or non-viable tendon or bone.

  • I: Infection or Inflammation

Examine the wound for infection, inflammation or other signs of infection. Are there clinical signs that there may be a problem with bacterial bioburden?

  • M: Moisture Balance

Is the wound too dry, or does it have excess exudate?

What is the objective of topical therapy: absorption or drainage?

  • E: Edge of wound—non-advancing or undermined

Examine the edges of the wound. Are the edges undermined, or is the epidermis failing to migrate across the granulation tissue?

The DIMES acronym is very similar to TIME:

  • Debridement (autolytic)

For wounds with the ability to heal, adequate and repeated debridement is an important first step in removing necrotic tissue. Debridement may also help healing by removing both senescent cells that are no longer capable of normal cellular activities and biofilms that may be shielding bacterial colonies.

  • Infection/Inflammation

The level of bacterial damage may include contamination (organisms present), colonization (organisms present which may cause surface damage if critically colonized) or infection. Treatment needs to make a match between the individual patient’s wound and the appropriate product.

  • Moisture balance

Clinicians need to create a careful balance in the wound such that the environment is neither too wet nor too dry. The environment itself will change as the wound heals.

  • Edge/Environment

The clinician should carefully examine and monitor the wound edge. If the wound edge is not migrating after appropriate wound bed preparation, and if healing appears to be stalled, then more advanced wound care therapies should be considered.

  • Supportive Products and Services

There are additional products which support wound healing yet don’t fall into one of these steps. For example, proper nutritional support is important to achieving the goal of a fully healed wound.

Extrinsic Factors

Extrinsic factors affecting wound healing include:

  • Mechanical stress
  • Debris
  • Temperature
  • Desiccation and maceration
  • Infection
  • Chemical stress
  • Medications
  • Other factors such as alcohol abuse, smoking, and radiation therapy

Mechanical Stress

Mechanical stress factors include pressure, shear, and friction. Pressure can result from immobility, such as experienced by a bed- or chair-bound patient, or local pressures generated by a cast or poorly fitting shoe on a diabetic foot. When pressure is applied to an area for sufficient time and duration, blood flow to the area is compromised and healing cannot take place. Shear forces may occlude blood vessels, and disrupt or damage granulation tissue. Friction wears away newly formed epithelium or granulation tissue and may return the wound to the inflammatory phase.

Debris

Debris, such as necrotic tissue or foreign material, must be removed from the wound site in order to allow the wound to progress from the inflammatory stage to the proliferative stage of healing. Necrotic debris includes eschar and slough. The removal of necrotic tissue is called debridement and may be accomplished by mechanical, chemical, autolytic, or surgical means. Foreign material may include sutures, dressing residues, fibers shed by dressings, and foreign material which were introduced during the wounding process, such as dirt or glass.

Temperature

Temperature controls the rate of chemical and enzymatic processes occurring within the wound and the metabolism of cells and tissue engaged in the repair process. Frequent dressing changes or wound cleansing with room temperature solutions may reduce wound temperature, often requiring several hours for recovery to physiological levels. Thus, wound dressings that promote a “cooling” effect, while they may help to decrease pain, may not support wound repair.

Desiccation and Maceration

Desiccation of the wound surface removes the physiological fluids that support wound healing activity. Dry wounds are more painful, itchy, and produce scab material in an attempt to reduce fluid loss. Cell proliferation, leukocyte activity, wound contraction, and revascularization are all reduced in a dry environment. Epithelialization is drastically slowed in the presence of scab tissue that forces epithelial cells to burrow rather than freely migrate over granulation tissue. Advanced wound dressings provide protection against desiccation.

Maceration resulting from prolonged exposure to moisture may occur from incontinence, sweat accumulation, or excess exudates. Maceration can lead to enlargement of the wound, increased susceptibility to mechanical forces, and infection. Advanced wound products are designed to remove sources of moisture, manage wound exudates, and protect skin at the edges of the wound from exposure to exudates, incontinence, or perspiration.

Infection

Infection at the wound site will ensure that the healing process remains in the inflammatory phase. Pathogenic microbes in the wound compete with macrophages and fibroblasts for limited resources and may cause further necrosis in the wound bed. Serious wound infection can lead to sepsis and death. While all ulcers are considered contaminated, the diagnosis of infection is made when the wound culture demonstrates bacterial counts in excess of 105 microorganisms per gram of tissue. The clinical signs of wound infection are erythema, heat, local swelling, and pain.

Chemical Stress

Chemical stress is often applied to the wound through the use of antiseptics and cleansing agents. Routine, prolonged use of iodine, peroxide, chlorhexidine, alcohol, and acetic acid has been shown to damage cells and tissue involved in wound repair. Their use is now primarily limited to those wounds and circumstances when infection risk is high. The use of such products is rapidly discontinued in favor of using less cytotoxic agents, such as saline and nonionic surfactants.

Medication

Medication may have significant effects on the phases of wound healing. Anti-inflammatory drugs such as steroids and non-steroidal anti-inflammatory drugs may reduce the inflammatory response necessary to prepare the wound bed for granulation. Chemotherapeutic agents affect the function of normal cells as well as their target tumor tissue; their effects include reduction in the inflammatory response, suppression of protein synthesis, and inhibition of cell reproduction. Immunosuppressive drugs reduce WBC counts, reducing inflammatory activities and increasing the risk of wound infection.

Other Extrinsic Factors

Other extrinsic factors that may affect wound healing include alcohol abuse, smoking, and radiation therapy. Alcohol abuse and smoking interfere with body’s defense system, and side effects from radiation treatments include specific disruptions to the immune system, including suppression of leukocyte production that increases the risk of infection in ulcers. Radiation for treatment of cancer causes secondary complications to the skin and underlying tissue. Early signs of radiation side effects include acute inflammation, exudation, and scabbing. Later signs, which may appear four to six months after radiation, include woody, fibrous, and edematous skin. Advanced radiated skin appearances can include avascular tissue and ulcerations in the circumscribed area of the original radiation. The radiated wound may not become evident until as long as 10-20 years after the end of therapy.

Intrinsic Factors

Intrinsic factors that directly affect the performance of healing are:

  • Health status
  • Age factors
  • Body build
  • Nutritional status

Health Status

Chronic diseases, such as circulatory conditions, anemias and autoimmune diseases, influence the healing process as a result of their influence on a number of bodily functions. Illnesses that cause the most significant problems include diabetes, chronic obstructive pulmonary disease (COPD), arteriosclerosis, peripheral vascular disease (PVD), heart disease, and any conditions leading to hypotension, hypovolemia, edema, and anemia. While chronic diseases are more frequent in the elderly, wound healing will be delayed in any patient with a pre-existing underlying illness.

Chronic circulatory diseases which reduce blood flow, such as arterial or venous insufficiency, lower the amount of oxygen available for normal tissue activity and replacement. Anemias such as sickle-cell anemia result in reduced delivery of oxygen to tissues and decreased ability to support wound healing.

Normal immune function is required during the inflammatory phase by providing the WBCs (white blood cells) that orchestrate or coordinate the normal sequence of events in wound healing. Autoimmune diseases such as lupus and rheumatoid arthritis interfere with normal collagen deposition, and impair granulation.

Diabetes is associated with delayed cellular response to injury, compromised cellular function at the site of injury, defects in collagen synthesis, and reduced wound tensile strength after healing. Diabetes-related peripheral neuropathy (DPN), which reduces the ability to feel pressure or pain, contributes to a tendency to ignore pressure points and avoid pressure relief strategies.

Acquired Immune Deficiency Syndrome

Patients with acquired immunodeficiency syndrome (AIDS) have significant impact on the wound healing market as their numbers rise and their average life expectancy increases. Patients in the latter stages of the disease experience drastic reductions in mobility, activity, and nutritional status, placing them at high risk for the development of pressure ulcers. Minor scrapes or abrasions are at high risk for infection and may progress to full-thickness wounds requiring antibiotic therapy and aggressive wound management. Skin tumors, such as Kaposi’s sarcoma, lead to surgical incisions closed by secondary intention requiring the use of appropriate dressings.

The skin of AIDS patients becomes drier as the syndrome progresses. As the CD4+ T cell count falls below 400/mm3, pruritus increases and erythematous patches appear on the skin, progressing to ichthyosis and appearing as large polygonal scales, especially on the lower limbs. Histological changes include hyperkeratosis and thinning of the granular layer of the epidermis. As skin becomes more fragile, care must be exercised in the selection of tapes and adhesive dressings to avoid skin stripping and skin tears.

Age Factors

Observable changes in wound healing in the elderly include increased time to heal and the fragile structure of healed wounds. Delays are speculated to be the result of a general slowing of metabolism and structural changes in the skin of elderly people. Structural changes include a flattening of the dermal-epidermal junction that often leads to skin tears, reduced quality and quantity of collagen, reduced padding over bony prominences, and reduction in the intensity of the immune response.

Body Build

Body build can affect the delivery and availability of oxygen and nutrients at the wound site. Underweight individuals may lack the necessary energy and protein reserves to provide sufficient raw materials for proliferative wound healing. Bony prominences lack padding and become readily susceptible to pressure due to the reduced blood supply of wounds associated with bony prominences. Poor nutritional habits and reduced mobility of overweight individuals lead to increased risk of wound dehiscence, hernia formation, and infection.

Nutritional Status

Healing wounds, especially full-thickness wounds, require an adequate supply of nutrients. Wounds require calories, fats, proteins, vitamins and minerals, and adequate fluid intake. Calories provide energy for all cellular activity, and when in short supply in the diet, the body will utilize stored fat and protein. The metabolism of these stored substances causes a reduction in weight and changes in pressure distribution through reduction of adipose and muscle padding. Sufficient dietary calories maintain padding and ensure that dietary protein and fats are available for use in wound healing. In addition, adequate levels of protein are necessary for repair and replacement of tissue. Increased protein intake is particularly important for wounds where there is significant tissue loss requiring the production of large amounts of connective tissue. Protein deficiencies have been associated with poor revascularization, decreased fibroblast proliferation, reduced collagen formation, and immune system deficiencies.

Reduced availability of vitamins, minerals, and trace elements will also affect wound healing. Vitamin C is required for collagen synthesis, fibroblast functions, and the immune response. Vitamin A aids macrophage mobility and epithelialization. Vitamin B complex is necessary for the formation of antibodies and WBCs, and Vitamin B or thiamine maintains metabolic pathways that generate energy required for cell reproduction and migration during granulation and epithelialization. Iron is required for the synthesis of hemoglobin, which carries oxygen to the tissues, and copper and zinc play a role in collagen synthesis and epithelialization.

Adequate nutrition is an often-overlooked requirement for normal wound healing. Inadequate protein-calorie nutrition, even after just a few days of starvation, can impair normal wound-healing mechanisms. For healthy adults, daily nutritional requirements are approximately 1.25-1.5 g of protein per kilogram of body weight and 30-35 calories/kg.  These requirements should be increased for those with sizable wounds.

Malnutrition should be suspected in patients presenting with chronic illnesses, inadequate societal support, multisystem trauma, or GI or neurologic problems that may impair oral intake. Protein deficiency occurs in about 25% of all hospitalized patients.

Chronic malnutrition can be diagnosed by using anthropometric data to compare actual and ideal body weights and by observing low serum albumin levels. Serum prealbumin is sensitive for relatively acute malnutrition because its half-life is 2-3 days (vs 21 d for albumin). A serum prealbumin level of less than 7 g/dL suggests severe protein-calorie malnutrition.

Vitamin and mineral deficiencies also require correction. Vitamin A deficiency reduces fibronectin on the wound surface, reducing cell chemotaxis, adhesion, and tissue repair. Vitamin C is required for the hydroxylation of proline and subsequent collagen synthesis.

Vitamin E, a fat-soluble antioxidant, accumulates in cell membranes, where it protects polyunsaturated fatty acids from oxidation by free radicals, stabilizes lysosomes, and inhibits collagen synthesis. Vitamin E inhibits prostaglandin synthesis by interfering with phospholipase-A2 activity and is therefore anti-inflammatory. Vitamin E supplementation may decrease scar formation.

Zinc is a component of approximately 200 enzymes in the human body, including DNA polymerase, which is required for cell proliferation, and superoxide dismutase, which scavenges superoxide radicals produced by leukocytes during debridement.


From, “Worldwide Wound Management, Forecast to 2024: Established and Emerging Products, Technologies and Markets in the Americas, Europe, Asia/Pacific and Rest of World”. Report #S251. Available online.

Cardiovascular procedure volume growth (interventional and surgical)

Cardiovascular surgical and interventional procedures are performed to treat conditions causing inadequate blood flow and supply of oxygen and nutrients to organs and tissues of the body. These conditions include the obstruction or deformation of arterial and venous pathways, distortion in the electrical conducting and pacing activity of the heart, and impaired pumping function of the heart muscle, or some combination of circulatory, cardiac rhythm, and myocardial disorders. Specifically, these procedures are:

  • Coronary artery bypass graft (CABG) surgery;
  • Coronary angioplasty and stenting;
  • Lower extremity arterial bypass surgery;
  • Percutaneous transluminal angioplasty (PTA) with and without bare metal and drug-eluting stenting;
  • Peripheral drug-coated balloon angioplasty;
  • Peripheral atherectomy;
  • Surgical and endovascular aortic aneurysm repair;
  • Vena cava filter placement
  • Endovenous ablation;
  • Mechanical venous thrombectomy;
  • Venous angioplasty and stenting;
  • Carotid endarterectomy;
  • Carotid artery stenting;
  • Cerebral thrombectomy;
  • Cerebral aneurysm and AVM surgical clipping;
  • Cerebral aneurysm and AVM coiling & flow diversion;
  • Left Atrial Appendage closure;
  • Heart valve repair and replacement surgery;
  • Transcatheter valve repair and replacement;
  • Congenital heart defect repair;
  • Percutaneous and surgical placement of temporary and permanent mechanical cardiac support devices;
  • Pacemaker implantation;
  • Implantable cardioverter defibrillator placement;
  • Cardiac resynchronization therapy device placement;
  • Standard SVT & VT ablation; and
  • Transcatheter AFib ablation

For 2016 to 2022, the total worldwide volume of these cardiovascular procedures is forecast to expand on average by 3.7% per year to over 18.73 million corresponding surgeries and transcatheter interventions in the year 2022. The largest absolute gains can be expected in peripheral arterial interventions (thanks to explosive expansion in utilization of drug-coated balloons in all market geographies), followed by coronary revascularization (supported by continued strong growth in Chinese and Indian PCI utilization) and endovascular venous interventions (driven by grossly underserved patient caseloads within the same Chinese and Indian market geography).

Venous indications are also expected to register the fastest (5.1%) relative procedural growth, followed by peripheral revascularization (with 4.0% average annual advances) and aortic aneurysm repair (projected to show a 3.6% average annual expansion).

Source: MedMarket Diligence, LLC; “Global Dynamics of Surgical and Interventional Cardiovascular Procedures, 2015-2022,” (Report #C500).

Geographically, Asian-Pacific (APAC) market geography accounts for slightly larger share of the global CVD procedure volume than the U.S. (29.5% vs 29,3% of the total), followed by the largest Western European states (with 23.9%) and ROW geographies (with 17.3%). Because of the faster growth in all covered categories of CVD procedures, the share of APAC can be expected to increase to 33.5% of the total by the year 2022, mostly at the expense of the U.S. and Western Europe.

However, in relative per capita terms, covered APAC territories (e.g., China and India) are continuing to lag far behind developed Western states in utilization rates of therapeutic CVD interventions with roughly 1.57 procedures per million of population performed in 2015 for APAC region versus about 13.4 and 12.3 CVD interventions done per million of population in the U.S. and largest Western European countries.

Source: MedMarket Diligence, LLC; “Global Dynamics of Surgical and Interventional Cardiovascular Procedures, 2015-2022,” (Report #C500).


Global Cardiovascular Procedures report #C500 details the current and projected surgical and interventional therapeutic procedures commonly used in the management of acute and chronic conditions affecting myocardium and vascular system.

Forgotten Opportunities: Early Stage Biotech and Medtech Investment

Due to the uncertainty in the development, clinical testing, and regulatory approval of both biotech and medical technologies, which increasingly have to be viewed with the same competitive lens, investors have over the past few years shied away from seed stage or Series A stage company investment in favor of those nearer to market introduction. However, with the advent of a great number of new technologies and advances in the underlying science, there is enormous opportunity to identify companies and emerging sectors arising from these advances. The problem in identifying realistically promising companies is that it must be done so without falling prey to the bad investment practices in the past that ensued from a poor understanding of the technologies and their remaining commercial hurdles. Without careful consideration of remaining scientific development needed, the product’s target market, its competitors, and the sum total of the company’s capabilities to commercialize these technologies, investment in these areas will fall short of investment objectives or fail them outright.

While any of these considerations have the capacity to preempt a successful market introduction, a failure to understand the science behind the product and its remaining development hurdles to commercialization is likely to be the biggest cause of failure.

“We’ve already had one glaring example of a company, and its investors, learning the hard way that health and science advisors are important: Theranos.” (link)

Venture Capital has backed away from early stage investment

Earlier stage investment, with its higher risk, has higher potential reward, so there is a big need for more effective evaluation of potential early stage investments in order to (1) seize these opportunities that will otherwise potentially be lost with the shift to later stage fundings, (2) sort out those companies/technologies with overwhelming commercialization hurdles from those that will profitably tap an opportunity, and (3) gain the value of these opportunities before the innovation appreciates in value, driving up the price of the investment.

The Biotech Bubble

Biotech in the 1980s was enamored with companies pursuing “magic bullets” — technologies that had the potential to cure cancer or heart disease or other conditions with large, untapped or under-treated populations. With few exceptions, these all-in-one-basket efforts were only able achieve a measure of humility in the VCs who had poured volumes of money into them.

Here was evidenced a fundamental problem with biotech at a time when true scientific milestones were being reached, including successes in mapping the human genome: Landmark scientific milestones do not equate with commercial success.

As a result, money fled from biotech as few products could make it to market due to persistent development and FDA hurdles. By the late 1980s, many biotechs saw three quarters of their value disappear.

A Renewed Bubble?

The status of biomedical science and technology, with multiple synergistic developments, will lead to wild speculation and investment, potentially leading to yet another investment bubble. However, there will be advances that can point to real timelines for market introduction that will support investment.

Recent advances, developments and trends supporting emerging therapeutics

  1. Stem cells. A double-edged sword in that these do represent some the biggest therapeutics that will emerge, yet caution is advised since the mechanisms to control stem cells are not always sufficient to prevent their nasty tendency to become carcinogenic.
  2. Drug discovery models, such as using human “organoids” and other cell-based models to test or screen new drugs.
  3. Systems to accelerate the rapid evaluation of hundreds, perhaps, thousands of potential drugs before moving to animal models or preclinicals.
    1. Machine-learning algorithms
    2. Cell/tissue/organ models
    3. Meta-analysis, the practice of analyzing multiple, independently produced clinical data to draw conclusions from the broader dataset.
  4. Cross-discipline science
    1. cell biologists, immunologists, molecular biologists and others have a better understanding of pathology and therapeutics as a result of information sharing; plus BIG DATA (e.g., as part of the “Cancer Moonshot”). Thought leaders have called for collection and harnessing of patient data on a large scale and centralized for use in evaluating treatments for specific patients and cancer types.
    2. Artificial intelligence applied to diagnosis and prescribed therapeutics (e.g., IBM Watson).
    3. Examples of resulting therapies, at a minimum, include multimodal treatment – e.g., radiotherapy and immunotherapy – but more often may be represented in considerably more backend research and testing to identify and develop products with greater specificity, greater efficacy, and lowered risk of complications.
  5. Materials science developments, selected examples:
    1. Scaffolds in tissue engineering
    2. Microgels
    3. Graphene
    4. Polyhedral boranes
    5. Nanometric imprinting on fiber
    6. Knitted muscles to provide power link
    7. 3-D printed skin and more complex organs to come
    8. Orthopedic scaffolds made from electrospun nanofibers
  6. CAR-T (chimeric antigen receptor T cell therapy)
  7. CRISPR/Cas-9. Gene editing
    1. Removal, insertion of individual genes responsible for disease
    2. Potential use for creating chimeras of human and other (e.g., pig) species in order to, for example, use pigs for growing human organs for transplant.
  8. Smart devices: smart biopsy needles, surgical probes to detect cancer margins, artificial pancreas. Devices using information

 

We sum this up with these prerequisites for investment:

Prerequisites for Early Stage Med/Bio Investment

  1. A fully understood and managed gap between scientific advance and commercial reality.
    1. Investment must be tied to specific steps (prototyping, preclinicals, clinicals, physician training, etc.).
  2. A management team qualified in commercializing medtech or biotech products.
    1. CEOs (and/or Chief Medical Officers, Chief Scientific Officers) with medical science backgrounds (MD, PhD) favored over CPAs or even JDs.
  3. Reimbursement strategy pursued as something more than an afterthought
  4. Technology development in sync with end-user acceptance and training to leverage the benefits:
    1. Easier to use
    2. Fewer complications
    3. Attractive physician revenue streams
  5. Broad competitive advantage pursued:
    1. Product benefits must stand up against all competition, irrespective of technology type (devices competing with drugs, biotech).
    2. Benefits of reducing the cost of care for an existing patient population are paramount.
    3. Competitive advantage must consider the trend in technology development to avoid being disrupted by other products soon to reach the market.
  6. Predefined exit strategy; selected examples:
    1. Positioning to add innovation to a mid-cap or large-cap medtech or biotech as acquirers.
    2. Development of platform technologies for licensing or sale.
    3. IPO

 

Future investments are likely to track the historical focus on specific diseases and conditions:

Source: MedMarket Diligence, LLC and Emerging Therapeutic Company Investment and Deal Trends; Biotechnology Innovation Organization.


MedMarket Diligence, mediligence.com, tracks medical and biotechnology development to provide meaningful insights for manufacturers, investors, and other stakeholders.

High strength medical and surgical glues, growth to 2022

High strength medical and surgical glues currently command a $1.2 billion market that will grow to $1.7 billion by 2022, representing a 6.4% compound annual growth rate. More importantly, however, is that during this time frame the market will undergo steady shifts, including the regional representation, with growth slowing in western markets relative to Asia-Pacific and the rest of the world.

Below is illustrated the size versus growth of high strength glues in the U.S., Western Europe, Asia-Pacific and Rest of World.

Source: MedMarket Diligence, LLC; Report #S290. Order online.

The resulting differential growth over this period will result in a shift in the regional market balance, as shown below.

Source: MedMarket Diligence, LLC; Report #S290. Order online.

Source: MedMarket Diligence, LLC; Report #S290. Order online.

The best medtech investment opportunities

In reviewing patents, fundings, technology development trends, market development, and other hard data sources, we feel these are some of the strongest areas for investment in not only the medical device side of medtech, but also the broader biomedical technology arena:

  • Materials technologies
    • graphene
    • bioresorbables
    • biosensors
    • polymers
    • bioadhesives
  • Cell therapy and tissue engineering
    • cell-based treatments (diabetes, spinal cord injury, traumatic brain injury)
    • extracellular matrices in soft tissue repair and regeneration
  • Nanotechnology (subject of forthcoming report)
    • nano coatings
    • nano- and micromedical technologies for localized drug delivery
    • nanoparticles
  • 3D printing
    • prototype development
    • patient-specific implants
  • Minimally- and non-invasive technologies
    • transcatheter alternatives to surgery
    • NOTES (natural orifice transluminal endoscopic surgery)
  • Diabetes non-invasive glucose testing
  • Intraoperative surgical guidance
    • Cancer probes (e.g., fluorescent or optical coherence tomography, frozen section, cytologic imprint analysis, ultrasound, micro-computed tomography, near-infrared imaging, and spectroscopy)
  • neurostimulation and neuromodulation
  • point-of-care diagnostics
  • point-of-care imaging
  • AI-enhanced devices

In addition, there are many areas in healthcare in which there is much untapped demand with problems that, so far, seem to have eluded medtech solutions. These include infection control (Zika, MRSA, TB, nosocomial infections, etc.), chronic wound treatment (including decubitus/stasis/diabetic ulcers), type 2 diabetes and obesity.

 

Medical and Surgical Sealants, Glues, and Hemostats, to 2022

There are several different classes of surgical sealants, glues and hemostatic products used to prevent or stop bleeding, or to close a wound or reinforce a suture line. These include fibrin sealants, surgical sealants, mechanical hemostats, active hemostats, flowable hemostats, and glues. Both sealants and medical glues are increasingly used either as an adjunct to sutures or to replace sutures.

Medical Sealants

Fibrin sealants are made of a combination of thrombin and fibrinogen. These sealants may be sprayed on the bleeding surface, or applied using a patch. Surgical sealants might be made of glutaraldehyde and bovine serum albumin, polyethylene glycol polymers, and cyanoacrylates.

Sealants are most often used to stop bleeding over a large area. If the surgeon wishes to fasten down a flap without using sutures, or in addition to using sutures, then the product used is usually a medical glue.

Source: MedMarket Diligence, LLC; Report #S290.

Hemostatic Products

The surgeon and the perioperative nurse have a variety of hemostats from which to choose, as they are not all alike in their applications and efficacy. Selection of the most appropriate hemostat requires training and experience, and can affect the clinical outcome, as well as decrease treatment costs. Some of the factors that enter into the decision-making process include the size of the wound, the amount of hemorrhaging, potential adverse effects, whether the procedure is MIS or open surgery, and others.

Active hemostats contain thrombin products which may be derived from several sources, such as bovine pooled plasma purification, human pooled plasma purification, or through human recombinant manufacturing processes. Flowable-type hemostats are made of a granular bovine or porcine gelatin that is combined with saline or reconstituted thrombin, forming a flowable putty that may be applied to the bleeding area.
Mechanical hemostats, such as absorbable gelatin sponge, collagen, cellulose, or polysaccharide-based hemostats applied as sponges, fleeces, bandages, or microspheres, are not included in this analysis.

Source: MedMarket Diligence, LLC; Report #S290.

Medical Glues

Sealants and glues are terms which are often used interchangeably, which can be confusing. In this report, a medical glue is defined as a product used to bond two surfaces together securely. Surgeons are increasingly reaching for medical glues to either help secure a suture line, or to replace sutures entirely in the repair of soft tissues. Medical glues are also utilized in repairing bone fractures, especially for highly comminuted fractures that often involve many small fragments. This helps to spread out the force-bearing surface, rather than focusing weight-bearing on spots where a pin has been inserted.

Thus, the surgeon has a fairly wide array of products from which to choose. The choice of which surgical hemostat or sealant to use depends on several factors, including the procedure being conducted, the type of bleeding, severity of the hemorrhage, the surgeon’s experience with the products, the surgeon’s preference, the price of the product and availability at the time of surgery. For example, a product which has a long shelf life and does not require refrigeration or other special storage, and which requires no special preparation, usually holds advantages over a product which must be mixed before use, or held in a refrigerator during storage, then allowed to warm up to room temperature before use.

Source: MedMarket Diligence, LLC; Report #S290.


From “Worldwide Market for Medical and Surgical Sealants, Glues, and Hemostats, 2015-2022.” See details at link. Order online.

Regional Markets for Surgical Sealants, 2015 and 2022

The fastest growth in the sales of surgical sealants over the next decade will be in the Asia-Pacific region, driven primarily by very strong healthcare market growth in China, and reaching a CAGR (2016-2022) of at least 13.97%. The growth rate in China would be even higher, but will be dampened for the time being by the lack of surgeons trained in the proper use of these products, as well as the limitations of reaching a dispersed patient population. Nonetheless, the A/P share of the global sealants market will double in the next seven years!

Below illustrates the geographic distribution of surgical sealants (fibrin and others) in 2015.

Regional Markets for Sealants, Fibrin and Other Sealant Products,
2015 & 2022, USD Millions

2015screen-shot-2016-11-11-at-8-52-44-am

2022

screen-shot-2016-11-11-at-8-53-17-am

Source: MedMarket Diligence, LLC; Report #S290.


Report #S290 may be purchased online for PDF download or print delivery; in single, site, or global licenses.

Wound closure and healing via sealants, glues, hemostats in development

Natural tissue healing is a highly complex dance of processes that need to be working properly in order for the body to heal. Mammals have developed the ability to heal wounds rapidly through a cascade of processes that starts with hemostasis (blood clotting) to slow or stop the loss of blood. From the moment of injury, platelets start to aggregate, as well as starting to release cytokines, chemokines and hormones. Vasoconstriction takes place as the body tries to limit the loss of blood, and several vasoactive mediators come into play, including, norepinephrine, epinephrine, prostaglandins, serotonin, and thromboxane. Activated platelets lead to formation of a clot. Next, the inflammatory steps kick in, targeting and killing microbes and launching a natural internal debridement process, which serves to clean up any damaged tissue so that reconstruction may occur. Last in the cascade are the proliferative and maturation phases. These involve the deposition of new tissue matrix materials, and are intended to lead to reconstruction of tissue organelles and cellular structure. These healing steps actually overlap one another, and do not have strict times when each process begins or ends.

A delicate physiological balance must be maintained during the healing process to ensure timely repair or regeneration of damaged tissue. Wounds may fail to heal or have a greatly increased healing time when unfavorable conditions are allowed to persist. An optimal environment must be provided to support the essential biochemical and cellular activities required for efficient wound healing and to remove or protect the wound from factors that impede the healing process.

Factors affecting wound healing may be considered in one of two categories depending on their source. Extrinsic factors impinge on the patient from the external environment, whereas intrinsic factors directly affect the performance of bodily functions through the patient’s own physiology or condition. Factors which strongly affect wound healing include smoking, diabetes, age, oxygenation, stress, obesity, certain medications, alcoholism and nutrition.

Timescales for Development of
Sealants, Glues and Hemostat Products

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Source: MedMarket Diligence, LLC; Report #S290.

While product development continues apace, and companies are launching their products in new countries, launches of actual new products has been relatively slow. This is due most likely to the highly technical (read: expensive) nature of the product development, as well as the cost and time involved in running clinical trials, and the strong patent protection which has been erected, especially by the leading companies. The need for the products is there, but the required clinical testing is putting a brake on the markets.

In July 2015, HyperBranch announced the product launch of Adherus® AutoSpray Dural Sealant in the US. FDA clearance to market the product was obtained in March 2015. The absorbable sealant is intended for use in brain surgery and is applied over the sutures for dura repair to prevent cerebrospinal fluid from leaking out of the incision site. The Adherus® AutoSpray Dural Sealant is made of two solutions: a PEG ester solution and a polyethylenimine (PEI) solution. When mixed together, the solutions combine to form a sealant gel that is applied to the incision site. According to the company, the sealant is fully absorbed in about 90 days.

Cohera Medical launched its TissuGlu® in select US cities in November 2015. At this point, TissuGlu® is available in ten cities in the USA, while B. Braun is the distributor for the product in Germany, Spain and Portugal.

Sanyo Chemical launched its first medical device, Hydrofit, in February 2014. The company obtained the approval of the medical device under the Pharmaceutical Affairs Law in December 2011, filing it as a novel surgical hemostatic agent intended for anastomosing the arterial blood and artificial blood vessel in surgical procedures. According to the company, the product will be produced by Sanyo and marketed by Terumo.

In 2014, Cohera Medical, Inc. launched Sylys Surgical Sealant, which can be used in gastrointestinal surgery to decrease anastomotic leak. In the same year, Baxter also gained the FDA permission for Tisseel® fibrin sealant, which, according to the company, is used in almost all types of surgical procedures.

Mallinckrodt will invest in the commercial launch and ongoing market development of both PreveLeak and Raplixa in FY 2016. According to the company, both products are faster to prepare and easier to use and store than competing products. PreveLeak, a surgical sealant, is allegedly more flexible than hemostasis glue products. It is indicated for use in vascular reconstructions to achieve adjunctive hemostasis by sealing areas of leakage. PreveLeak is currently marketed in Europe through distributors.

In an example of a delayed launch, CryoLife has been working towards launch of PerClot in the US, but ran into litigation trouble with Medafor, a wholly-owned subsidiary of CR Bard. In November 2015, CryoLife announced that it had entered into a resolution with Medafor to end the patent dispute in the US District Court for the District of Delaware between the companies regarding PerClot. Under terms of the resolution, all parties agreed to end the litigation, jointly dismissing all claims and counterclaims with prejudice and waiving all appeal rights in this case.  Each party is to pay its own attorneys’ fees and costs associated with the litigation.  However, the court’s preliminary injunction entered March 31, 2015 with respect to CryoLife’s marketing and sale of PerClot in the US will remain in effect until the expiration of Medafor’s US Patent No. 6,060,461 (the “‘461 Patent”) on February 8, 2019. CryoLife management says that this will not upset their plans, as CryoLife does not expect to receive FDA market approval for PerClot before 2018, if then.


From “Sealants, Glues, Hemostats to 2022” (#S290).

Medical, Surgical Sealants — Fibrin and Others

screen-shot-2016-10-26-at-2-23-29-pmFibrin is the result of the combination of solutions of thrombin and fibrinogen. This forms a clot just as in the body during the coagulation cascade. The thrombin then breaks the fibrinogen molecules into smaller bits of another blood protein, called fibrin. Fibrin molecules arrange themselves into a lattice with strands cross-linked by the blood component, Factor XIII. This resulting cross-linked net helps to stabilize the clot.

Numerous variants of fibrin sealant exist, including autologous products. Other, non-fibrin sealant types are thrombin, collagen & gelatin-based sealants.

Fibrin sealants are used in the US in a wide array of applications; they are used the most in orthopedic surgeries, where the penetration rate is thought to be 25-30%. Fibrin sealants can, however, be ineffective under wet surgical conditions. The penetration rate in other surgeries is estimated to be about 10-15%.

Fibrin-based sealants were originally made with bovine components. These components were judged to increase the risk of developing bovine spongiform encephalopathy (BSE), so second-generation commercial fibrin sealants (CSF) avoided bovine-derived materials. The antifibrinolytic tranexamic acid (TXA) was used instead of bovine aprotinin. Later, the TXA was removed, again due to safety issues. Today, Ethicon’s (JNJ) Evicel is an example of this product, which Ethicon says is the only all human, aprotinin free, fibrin sealant indicated for general hemostasis. Market growth in the sealants sector is driven by the need for improved biocompatibility and stronger sealing ability—in other words, meeting the still-unsatisfied needs of physician end-users.

The current market penetration of sealant products in the US stands at about 25% of eligible surgeries, with their largest volume of use in orthopedics.

Selected Fibrin and Other Sealant Types*

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*Market status on each detailed in report S290.

Source: MedMarket Diligence, LLC; Sealants, Glues, Hemostats to 2022.

 

The Regimens for Assessing and Treating Wound Types

Wound treatment starts with diagnosis. Acute wounds are often surgically created, or dealt with in accident and emergency (A&E) settings. Diagnosis in the acute scenario usually focuses on cleanliness and tidying of the wound edges to enable securement using sutures or glue products. If major trauma has occurred, hemostats and sealants may be required. In the chronic scenario, diagnosis is a process that occurs at every treatment session. The practitioner will examine size, appearance and odor changes to the wound, and from this process determine the ideal management. In addition, it is likely that the physician will take samples to send for microbial assessment if infection becomes a concern.

Following diagnosis and assessment, treatment will be established based on known efficacy and cost of individual dressings, knowledge of the potential products that may be used, and their availability. This will be determined by reimbursement, local purchasing decisions, and resources.

For chronic wounds, treatment often involves symptoms; many products are designed to remove aesthetically unpleasant aspects of wounds such as exudates, smell, and visibility.

Management of exudates also has a wound-healing benefit. Too much exudate leads to hydrolytic damage and maceration of the tissue and surrounding skin. Too little moisture leads to drying out of the wound and cell death. As a result, many advanced wound management products have been developed to optimize the moist wound healing environment. As a huge variety of wound conditions arise, a large number of dressings has been developed to help manage the full range of circumstances that may be encountered. These include dressings made from foams, polyurethane films, alginates, hydrocolloids, and biomaterials to manage exudates, which may be present in vast quantities (perhaps as much as two liters per square meter per day). Other products are designed to moisten the wound to optimize healing (amorphous hydrogels for example).

Much of the advanced wound management market has evolved to improve exudates management in the home setting, in order to reduce the need for visits by practitioners and the associated cost.

Types and Uses of Select Wound Care Products

    
Dressing categoryProduct examplesDescriptionPotential applications
FilmHydrofilm, Release, Tegaderm, BioclusiveComes as adhesive, thin transparent polyurethane film, and as a dressing with a low adherent pad attached to the film.Clean, dry wounds, minimal exudate; also used to cover and secure underlying absorptive dressing, and on hard-to-bandage locations, such as heel.
FoamPermaFoam
PolyMem
Biatain
Polyurethane foam dressing available in sheets or in cavity filling shapes. Some foam dressing have a semipermeable, waterproof layer as the outer layer of the dressingFacilitates a moist wound environment for healing. Used to clean granulating wounds which have minimal exudate.
HydrogelHydrosorb Gel Sheet, Purilon, Aquasorb, DuoDerm, Intrasite Gel, GranugelColloids which consist of polymers that expand in water. Available in gels, sheets, hydrogel-impregnated dressings.Provides moist wound environment for cell migration, reduces pain, helps to rehydrate eschar. Used on dry, sloughy or necrotic wounds.
HydrocolloidCombiDERM, Hydrocoll, Comfeel, DuoDerm CGF Extra Thin, Granuflex, Tegasorb, Nu-DermMade of hydroactive or hydrophilic particles attached to a hydrophobic polymer. The hydrophilic particles absorb moisture from the wound, convert it to a gel at the interface with the wound. Conforms to wound surface; waterproof and bacteria proof.Gel formation at wound interface provides moist wound environment. Dry necrotic wounds, or for wounds with minimal exudate. Also used for granulating wounds.
AlginateAlgiSite, Sorbalgon Curasorb, Kaltogel, Kaltostat, SeaSorb, TegagelA natural polysaccharide derived from seaweed; available in a range of sizes, as well as in ribbons and ropes.Because highly absorbent, used for wounds with copious exudate. Can be used in rope form for packing exudative wound cavities or sinus tracts.
AntimicrobialBiatain Ag
Atrauman Ag
MediHoney
Both silver and honey are used as antimicrobial elements in dressings.Silver: Requires wound to be moderately exudative to activate the silver, in order to be effective
NPWDSNa
V.A.C. Ulta
PICO
Renasys (not in USA)
Prospera PRO series
Invia Liberty
Computerized vacuum device applies continuous or intermittent negative or sub-atmospheric pressure to the wound surface. NPWT accelerates wound healing, reduces time to wound closure. Comes in both stationary and portable versions.May be used for traumatic acute wound, open amputations, open abdomen, etc. Seems to increase burn wound perfusion. Also used in management of DFUs. Contraindicated for arterial insufficiency ulcers. Not to be used if necrotic tissue is present in over 30% of the wound.
Bioengineered Skin and Skin SubstitutesAlloDerm, AlloMax, FlexHD, DermACELL, DermaMatrix, DermaPure, Graftjacket Regenerative Tissue Matrix, PriMatrix, SurgiMend PRS, Strattice Reconstructive Tissue Matrix, Permacol, EpiFix, OASIS Wound Matrix, Apligraf, Dermagraft, Integra Dermal Regeneration Template, TransCyteBio-engineered skin and soft tissue substitutes may be derived from human tissue (autologous or allogeneic), xenographic, synthetic materials, or a composite of these materials.Burns, trauma wounds, DFUs, VLUs, pressure ulcers, postsurgical breast reconstruction, bullous diseases

Source: MedMarket Diligence, LLC; Report #S251.

In some cases, the wound may be covered by a black necrotic tissue or yellow sloughy material. These materials develop from dead cells, nucleic acid materials, and denatured proteins. In order for new tissue to be laid down, this dead material needs to be removed. It may be done using hydrolytic debridement using hydrogels that soften the necrotic tissue, or by the use of enzymes. Surgical debridement is another option, but non-surgical debridement has the advantage that it is usually less painful and can be performed with fewer materials, less expertise, and less mess. It is possible to perform non-surgical debridement in the home setting. Debridement can also be performed to selectively remove dead tissue and thus encourage repair. Enzymatic debriders have been able to command a premium price in the market, and built a sizeable share of the wound management market, particularly during the 1990s when treatment in the home environment increased as a result of reductions in hospital-based treatment. These products are described in the section on cleansers and debriders.

Occasionally healthcare practitioners put maggots to work for wound debridement. Though esthetically unpleasant, maggots are very effective debriding agents because they distinguish rigorously between dead and living tissue. Military surgeons noticed the beneficial effect of maggots on soldiers’ wounds centuries ago, but maggot debridement therapy (MDT) as it is practiced today began in the 1920s and has lately been undergoing something of a revival. The maggots used have been disinfected during the egg stage so that they do not carry bacteria into the wound. The larvae preferentially consume dead tissue, they excrete an antibacterial agent, and they stimulate wound healing.

At the other end of the technological scale are skin substitutes, which have been developed to help in the management of extensive wounds such as burns. Autologous skin grafting is a well-established therapeutic technique; postage-stamp-sized sections of healthy skin are cultured and grown in vitro, then placed over the raw wound surface to serve as a focus for re-epithelialization. However, this process takes time; the wound is highly vulnerable to infection while the skin graft is being grown. A number of companies have developed alternatives in the form of synthetic skin substitutes. These are described further in the next section of the report.

A number of products have also been developed to deal with sloughy and infected wounds. These often incorporate antimicrobial agents. Often, infected wounds have a very unpleasant odor; a range of odor control dressings has arisen to deal with this.

Once wounds begin to heal, the amount of exudate starts to decrease. Some dressing products preserve moisture but are also non-adhesive, so that the dressing does not adhere to the new epithelializing skin. These products are called non-adherent dressings and include a range of tulle dressings, which usually consist of a loose weave of non-adherent fabric designed to allow exudates to pass through the gaps. A subgroup of dressings is designed to keep the skin moist in order to reduce scarring after healing.

For wounds that do not appear to be healing, a number of companies have explored the potential to add growth factors and cells to promote and maintain healing. In addition, companies have attempted to use energy sources to accelerate wound healing, and these are described in the section on physical treatments. The main example of physical treatment is the use of devices which apply negative pressure over the wound and have been shown to dramatically shorten the healing of diabetic ulcers and other chronic wounds.

Often, a dressing will serve more than one purpose. Therefore, it is difficult to generalize and collect only dressings that serve one purpose into a single category. For example, Systagenix’s Actisorb Plus (Systagenix is now owned by Acelity) is a woven, low-adherent odor control antimicrobial dressing designed to optimize moist wound healing through its exudates handling properties.


From, Worldwide Wound Management, Forecast to 2024; MedMarket Diligence, LLC.