Components used in surgical sealants

While fibrin is a biological sealant that has been harnessed by several companies to provide tissue sealing, a wide variety of other components and component combinations have been developed for sealant use.

Below are sealant formulations from selected participants in the market for surgical sealants:

Sealant Components by Manufacturer

CompanySealant component(s)
AdhesysPolyurethane
CoheraUrethane & lysine
EndomedixDextran and chitosan biopolymers
Gecko BiomedicalProprietary, light-activated, synthetic elastomer
GrifolsFibrin sealant
BaxterHuman fibrinogen and thrombin
EthiconFibrin sealant
BardHydrogel
TakedaFibrin sealant
The Medicines CompanyFibrin sealant, and synthetic sealant
CryoLifeBovine serum albumin and glutaraldehyde adhesive
HyperbranchActivated polyethylene glycol polyethlyeneimine
Integra LifesciencePolyethylene glycol hydrogel
LifeBondPolymer hydrogel matrix
Ocular TherapeutixPolyethylene glycol and trilysine
SealantisAlga-mimetic tissue adhesives

Source: MedMarket Diligence, LLC; Report #S290.

Biopolymers in orthopedics

Polymers for use as biomaterials in orthopedics, in addition to the demand for biocompatibility and non-toxicity, must have appropriate degrees of thermoplasticity, strength, crystallinity, degradation characteristics and hydrophilicity . Following are the main polymers used as biomaterials in orthopaedic and other applcations.

Poly-L-Lactic Acid (PLLA).  Polymer-based absorbable implants were first used in the early 1960s when American Cyanamid developed Dexon, a polyglycol material that was used as a resorbable suturing material. It was commercialized by Davis and Geck in 1970. When blended with polylactic acid (PLA), polyglycol forms a copolymer structure that breaks down gradually in the presence of bodily fluids through hydrolysis. The main resorbable medical grade polymer in current use is Poly-L-Lactic Acid (PLLA). It is more hydrophobic than PLA or PGA and maintains its structure in the body for longer; it is used in the manufacture of interference screws, soft tissue anchors, urological stents, tacks and staples.

Polymethylmethacrylate (PMMA).  This is the most commonly used orthopedic cement, used primarily to anchor hip stems in hip arthroplasty operations. It is also commonly used in the treatment vertebral compression fractures.

Polytetrafluoroethylene (PTFE).  PTFE was discovered in 1938 by chemists at DuPont, but was not marketed until after World War II. It is a fluorinated carbon with a high molecular, partly crystalline structure, resistant to virtually all chemicals. It offers an extremely wide working temperature range, from -200 to +300 °C. Its surface is adhesion-resistant due to shielding of the carbon chain by fluorine atoms.

A major use of PTFE is to make the prosthesis for the Anterior Cruciate Ligament (ACL) repair procedure. The ACL has considerable strength and modulus due to an aligned type I collagen network that bears great loads while undergoing little deformation. However, while the ACL’s mechanical properties increase during development, they begin to deteriorate with age and may therefore need to be augmented by prosthesis.

PTFE is also used in graft augmentation devices to protect biological grafts. Its intended use is to be a temporary load-bearing device and it does not require long-term performance capability. Apart from its use in graft augmentation, PTFE is also used in microporous hydrophobic membranes (MHM) that are used in products such as vented blood warmers, in-line suction filters and vented suction containers.

Polyurethane The Polymer Technology Group produces polyurethane bionate, used in applications that have a potential mode of degradation such as pacemaker leads; also as base polymers for surface modification, known as surface modifying end groups (SMEs). SMEs can permanently modify surface properties, such as blood compatibility, abrasion resistance, coefficient of friction, and resistance to degradation in implants.

Polyvinyl chloride (PVC). Vinyl has proved to be one of the most successful modern synthetic materials; it is a polymer formed by chlorine (about 57 percent by weight), carbon and hydrogen. It is long-lasting and safe in production, use and disposal. Typical uses for vinyl in the healthcare field include blood and IV bags, dialysis tubing, catheters, labware, pressure monitoring tubing, breathing tubes and inhalation masks. Vinyl is durable, sterilizable, non-breakable and cost-effective.

Polydimethylsiloxane (PDMS or silicone).  Silicones are synthetic polymers with a linear repeating silicon-oxygen backbone. However, organic groups attached directly to the silicon atoms by carbon-silicon bonds prevent formation of the 3D network found in silica.. Silicone is used in a variety of fields such as medicines, food processing, and a wide range of medical devices as well as putty and sealants. Silicone oil is commonly used as a lubricant in syringes and blood giving sets. Silicones are used during surgery to repair retinal detachment. Silicones are also used for breast prosthesis and in topical applications.

Polyester.  Polyethylene terephthalate (PET)—linear and aromatic polyester—was first manufactured by DuPont in the late 1940s. It is still known by the original trade name of Dacron. Current medical applications of PET include implantable sutures, surgical mesh, vascular grafts, sewing cuffs for heart valves, and components for percutaneous access devices.

PET sutures have been used in the medical field for half a century and are especially valuable for critical procedures, where strength and stable performance over a long duration is necessary. Woven PET is used in surgical meshes for abdominal wall repair and in applications requiring surgical “patching.”

Synthetic vascular prostheses made of woven as well as knitted PET are used in the repair of the thoracic aorta, ruptured abdominal aortic aneurysms, and to replace iliac, femoral, and popliteal vessels. PET is also used as a sewing cuff around the circumference of the heart valves to promote tissue ingrowth and to provide a surface to suture the valve to the surrounding tissue. Percutaneous tunneled catheters also use PET cuff to stabilize catheter location and minimize bacterial migration through the skin.

Polymer Biomaterials Used in Orthopaedics

 

Polymer Type

Orthopaedic Application

PLLA, PGA, PLA

Soft Tissue Anchors, Screws, Staples

PMMA

Bone Cement

Polyurethane

Facial Prostheses

PDMS

Bones and Joints

Nylons

Joints

 

Source: MedMarket Diligence, LLC; Report #M625, "Emerging Trends, Technologies and Opportunities in the Markets for Orthopedic Biomaterials, Worldwide."

 

Bioresorbable Polymers

There is an increasing demand for biodegradable or bioresorbable fixation implants for use in procedures such as shoulder reconstruction, small joint fixation, meniscal repair and cruciate ligament fixation . The total number of such procedures in the USA is estimated to be more than 250,000 each year. The biodegradable polymers used to meet this demand include polyglycolide (PGA), polyglycolide-co-lactide, polylactic acid (PLA), and poly-L-lactic acid (PLLA).
 

Orthopedic Biomaterials, Worldwide Market Segmentation

Biomaterial is an abbreviated form of the term biocompatible material, which can be defined as “a synthetic or natural material used to replace part of a living system or to function in intimate contact with living tissue”. Biomaterials are intended to interface with biological systems; they may be viable or non-viable. Artificial hips, vascular stents, artificial pacemakers and catheters are all made from different biomaterials.

The category of biomaterials now generally includes biomimetic materials – synthetic constructs with compositions and properties similar to biological materials. Calcium hydroxyapatite, used as a coating on artificial hips, is a typical example; it is used as a bone replacement and facilitates attachment of an implant to living bone. The term “orthopaedic biomaterials” applies, clearly, to biomaterials used to replace, augment, heal or otherwise enhance the function of bone which is damaged or deficient as a result of disease or trauma.

The orthopaedic biomaterials field is like a cake that can be cut in various ways; for example by the types of materials used, the different structures involved, and by the clinical uses to which they are put. And of course the business of orthopaedic biomaterials can involve analysis of the market (actual and potential) and of the industry which supplies these materials and the devices of which they are made.  Segmentation of the orthopedic biomaterials market can be made as follows:

  • Bone
  • Polymers
  • Ceramics
  • Other Orthopedic Biomaterials
    • Growth Factors
    • Surgical Sealants and Glues
    • Tissue Engineering

 

Below is the geographic segmentation of the worldwide market for orthopedic biomaterials (drawn from Report #M625):

 
The current valuation of the orthopaedic biomaterials segment is around $5 billion, representing over 17% of the orthopaedic total. It is also estimated that this market segment will grow at over 13% per year, which is more than double the rate for the overall orthopaedics market. At this rate the biomaterials segment will achieve a value of $9.4 billion by 2011 and will represent 28% of all orthopaedic product sales.

 


Drawn from “Emerging Trends, Technologies and Opportunities in the Markets for Orthopedic Biomaterials, Worldwide,” report #M625. This report may be purchased online or via Google Checkout, below.