Drug Delivery

Compared to standard clinical catheters, microporous catheters are designed to deliver therapeutic agents (small molecules) to cells with greater and more even distribution in soft tissues. For example, microporous catheters can deliver 10 times greater distribution of adenoviral–mediated gene transfer in rodent brains than a standard 28–gauge needle.

Central Nervous System Drug Delivery

Millions of Americans are afflicted by neurogenerative and malignant diseases affecting the central nervous system (CNS). For many of these diseases, such as Parkinson’s, Alzheimer’s and high grade primary brain tumors, there is currently no curative therapy. Even when effective therapeutic agents are identified, delivery into the CNS at therapeutic concentrations and sufficient distribution is presently difficult to reach clinical efficiency.

Many drugs of larger molecular size andweight are unable to pass the blood–brain barrier. Overcoming the drug–delivery obstacles to the CNS is a critical step in attaining better clinical outcomes.

Direct infusion of drugs into the brain parenchyma using convection–enhanced delivery (CED) results in the treatment of large areas of brain tissue. CED relies on bulk flow to establish a pressure gradient over time, resulting in continuous convective flow and widespread distribution of the drug to the affected areas of the brain.

One limitation of conventional CED treatment involves the backflow of infusate along the catheter body at increased infusion rates, especially when an introducer has been used for catheter placement.

Another limitation relates to uneven distribution of infusate in tumor or injured tissue as opposed to normal brain tissue. The variability of normal brain tissues and the targeted areas of treatment creates challenges for getting the drug directly to the site.

Microporous catheters are designed to improve the distribution of drugs administered directly into the central nervous system and other tissues. Microporous catheters significantly increase the surface area where the drug or fluid is delivered, at much lower pressures.

Microporous catheters can reduce the risk for backflow, while creating overall higher flow rates.

Negative Pressure Wound Care Therapies

Twin Star has been developing microporous catheters for use with wounds in conjunction with negative pressure wound therapy and has demonstrated a reduction of tissue swelling and improved tissue viability in pre–clinical studies.

Negative Pressure Wound Therapy (NPWT) is widely used for managing open wounds. The effects of NPWT are thought to promote wound healing through several actions including a reduction in edema, and an increase in blood flow to the wound.

Extremity Compartment Syndrome

Extremity Compartment Syndrome (ECS) occurs when muscle tissues take on excess fluid in the confined spaces known as fascial compartments, creating pressure that reduces blood flow. Increased pressures can cause irreversible damage, over time. Swelling and inflammation following traumatic injuries, such as fractures, burns, or crush injuries are the most common cause of ECS, but it can also occur after vascular injury, reperfusion following ischemia, extravasation of fluid, external compression, or even rigorous muscle use.

Early diagnosis and treatment of ECS is critical to retaining function and preventing long–term negative outcomes, including fracture non–union, vascular and strength compromise, limb amputation, organ toxicity, and death. However, accurate, timely diagnosis has proven difficult with present tools¹, and the only available treatment is an invasive surgical procedure, fasciotomy, which has significant morbidity including infection, nerve damage, chronic venous insufficiency, skin grafting, and scarring². Despite the morbidity associated with fasciotomy,it is the current standard of care, and is recommended early and liberally on at–risk patients.

Twin Star Medical has sought to improve the management of this difficult condition with its novel catheter and monitoring technology. Continuous monitoring has been shown to increase diagnostic accuracy while reducing the time to diagnosis of ECS³. The therapeutic effect of the Twin Star microporous catheter technology is being investigated. The hypothesis is that by removing a small amount of interstitial fluid – through ultrafiltration – tissue pressures can be reduced, and tissue viability retained, without the need for fasciotomy. Published, controlled animal model studies suggest that tissue ultrafiltration reduces pressure and improves cellular viability⁴. Human pilot studies have been performed⁵, and a multi–center clinical trial is being planned to assess the relationship of interstitial fluid removal and pressure, need for fasciotomy, and long–term outcomes.

The Twin Star ECS System has been cleared by the FDA for the immediate or continuous measurement of intracompartmental pressures, and/or the withdrawal of fluid for subsequent analysis. The measured compartmental pressures can be used as an aid in the diagnosis of compartment syndrome. The ECS System has been exclusively licensed to Twin Star ECS, Inc. (twinstarecs.com). Product use for pressure reduction and/or therapeutic effect is investigational and has not been reviewed by the FDA.

Brain Injury

Brain swelling due to severe head trauma or strokes results in about 30% mortality and 30% severe disability in approximately 200,000 patients in the U.S. each year.

US annual medical costs exceed $35 billion for the care of stroke and traumatic brain injury (TBI) patients.

Traumatic brain injury is also a growing cause of long–term disability in head injuries sustained in war zones. This is becoming an issue of growing concern in modern warfare, where blast injuries are becoming common. Traumatic brain injury has been identified as the “signature injury” among those wounded in the current military engagements in Afghanistan and Iraq.

In both traumatic brain injury and stroke, brain swelling can occur and fluids accumulate within the brain space. When an injury occurs inside the skull, there is no place for swollen tissues to expand, and no tissues to absorb to drain excess fluid. This leads to an increase in the pressure, called intracranial pressure (ICP).

High ICP can cause delicate brain tissue to be crushed, or cut off vital blood flow to areas of the brain, compounding brain tissue damage.

Intracranial pressure is monitored through a catheter inserted through the skull and connected to a monitor that registers ICP.

Treatment for high ICP, may be a ventriculostomy, a procedure that drains cerebrospinal fluid (CSF) from the ventricles to bring the pressure down, or in severe cases trepanation, which removes a section of skull to provide room for swelling and drainage.

The physical and physiological factors of ICP are similar to compartment syndrome in the peripheral anatomy.

Twin Star’s system has been designed to reduce cerebral edema based on vaporization and removal of free water from the cerebro–spinal fluid (CSF) within the ventricles of the brain, using the Company’s microporous catheter technology.

Download Twin Star Medical’s “Cerebral Edema     Management in Traumatic Brain Injury: The Twin
    Star Approach”

Caution: Investigational device. Limited by U.S. federal law to investigational use.

Patents issued and pending.