Tolerability and Feasibility Pilot Clinical Study of a Large-Diameter Nerve Cap for Protecting and Preserving Terminated Nerve Ends
Abstract
Objectives and Rationale: When a nerve is injured, the axons within the nerve will attempt to regrow across the site of injury and into the nerve on the other side. However, if the nerve cannot repair itself, a sensitive, painful, tangled mass can develop at the end of the severed nerve. This mass is called a neuroma. Any severe trauma to an area containing nerves can lead to neuroma formation. Neuroma formation is especially prevalent in amputees; an estimated 80% of all amputees suffer from some form of related pain. This neuroma-related pain can severely impact quality of life, lead to repeated surgeries and reliance on pain medication, and prevent the effective use of prosthetics in amputees. One study found that 75 out of 75 patients with neuromas were severely limited in their ability to use prosthetics. Standard treatment of the nerve during amputations involves a “traction neurectomy,” during which the nerve is pulled, cut, and allowed to retract back into the stump. Surgeons can attempt to isolate the nerve from stimuli that could cause painful sensations by burying it in healthy tissue, but this causes additional trauma, often fails, and may be anatomically impossible in some surgical sites. A new technique called targeted muscle reinnervation (TMR) is a more effective technique for preventing neuromas, but it is only available in a few centers across the country and not all patients are candidates. Therefore, new, easy-to-use treatment methods are needed to prevent neuromas from forming, to enable more effective use of prosthetics, and to reduce dependence on opioid pain management. The objective of this study is to address the FY18 Peer-Reviewed Orthopaedic Research Program’s Rehabilitation Focus Area in Surgical Care of Peripheral Nerve Injuries by evaluating the safety and efficacy parameters of a neuroma prevention device, the AxoGuard® Nerve Cap. The AxoGuard® Nerve Cap is a patented, Food and Drug Administration (FDA) 510k-cleared device that is designed to physically partition and mechanically insulate axons that would otherwise form a neuroma. Neuromas cause pain because, when stimulated, they send signals that are interpreted by the brain as pain. The partitioning in the AxoGuard® Nerve Cap limits the interconnection between axons, which in turn limits axonal signaling caused by mechanical stimuli. Once implanted, the cap material forms a new soft tissue layer around the end of the nerve to provide the necessary cushioning to prevent mechanical stimuli from affecting the axons in the cap. Applicability and Impact: The AxoGuard® Nerve Cap offers an off-the-shelf solution for peripheral nerve surgeons to protect the ends of nerves that cannot otherwise be repaired. If successful, the AxoGuard® Nerve Cap could become the definitive treatment option to prevent and resolve chronic pain from neuromas following lower limb amputation. The AxoGuard® Nerve Cap was demonstrated to be effective in a rat model of neuroma formation and, based on these studies, small diameter (1-3 mm) Nerve Caps are already in use in the clinic. However, no animal model exists for neuroma formation in large-diameter nerves (5-7 mm). This study will assess safety and efficacy in preventing neuroma formation in large-diameter nerves in patients planning to undergo a secondary TMR procedure. The material used in the AxoGuard® Nerve Cap is FDA-approved, well-characterized, and has been used in millions of surgical implants; the clinical application represents minimal patient risk. Potential risks in addition to the general operative risks include infection; acute or chronic inflammation (initial application of surgical graft materials may be associated with transient, mild localized inflammation); and allergic reaction. Since this product is already FDA-cleared for clinical use, patients with large-diameter terminated nerve ends could begin receiving the Nerve Cap upon immediate completion of this study. This
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 19, 2019
- Source ID
- W81XWH1910487
Entities
People
- Ivica Ducic
Organizations
- AxoGen
- United States Army