A Pilot Multicenter, Prospective, Randomized, Subject-Blinded Comparative Study of Axoguard® Nerve Cap and Neurectomy for the Treatment of Symptomatic Neuroma and Prevention of Recurrent End-Neuroma Pain (REPOSE)
Ryan Pereira, DPM, FACFAS1; Damien Dauphinee, DPM, FACFAS, FAENS, CWS-P2; Stephen Frania, DPM, FACFAS3; Paul Klein, DPM, FACFAS, FAENS4; Alan Garrett, DPM, FACFAS5; Craig Martin, DPM, FAENS6; Carl Van Gils, DPM, FACFAS, FAENS7; Craig Thomajan, DPM, FACFAS, FAENS8; Ivica Ducic9
1Anastasia Medical Group, St. Augustine, FL; 2Complete Foot & Ankle Care of North Texas, Denton, TX; 3Foot and Ankle Specialists of Ohio, Westlake, OH; 4North Jersey Podiatry, WAYNE, NJ; 5Acclaim Bone & Joint Institute, Fort Worth, TX; 6Premier Ankle & Foot Specialists, Hanover, PA; 7Intermountain Healthcare, St. George, UT; 8Austin Foot and Ankle Specialists, Austin, TX; 9Washington Nerve Institute
Introduction: When a nerve is disrupted, axons may grow in a disorganized fashion forming a tangled bulbous mass called a neuroma, which can cause pain when stimulated. Attempts to treat symptomatic neuroma formation have been met with limited success. Contemporary treatments include surgical methods to remove neuromas or pharmacological therapies directed at pain management. The current standard of care for surgical neuroma management involves either traction neurectomy, which has a high rate of neuroma recurrence, or burying the nerve stump into adjacent muscle or bone. While burying can prevent mechanical stimulation that would cause pain, this procedure does little to manage the resulting regenerate and the subsequent neuroma that will form. In order to address the need for better neuroma treatment strategies we evaluated a nerve termination cap with internal chambering (Axoguard® Nerve Cap) that was designed to protect a peripheral nerve end and to separate it from the surrounding environment to reduce the development of symptomatic or painful neuroma. Previously, it was shown to reduce the formation of symptomatic neuroma in an animal model. The objective of this pilot clinical study is to compare early pain scores at baseline (6 weeks pre-surgery) and 12 weeks post-surgery in 15 patients undergoing surgery for symptomatic neuromas in the foot at up to 10 centers in the United States.
Results: Currently, all 15 patients have been enrolled in the study with a mean age of 55 years ±12 (80% female and 20% male). Seven patients have made it to the 4-week timepoint with a mean reduction in pain of -51.5 ± 38.7mm on a 100mm Visual Analog Scale (VAS). Five of those 7 patients have made it to the 12-week timepoint with a mean reduction in pain of -78 ± 13.5mm on the VAS. This study is ongoing and expected to be complete by Q4 2019.
Discussion: Neuromas in the foot are a suitable model for neuromas throughout the body as the nerves in the foot are subjected to more mechanical stimulation than most other anatomical areas and therefore represent a worst-case scenario. The pilot phase of the study found that patients undergoing neuroma treatment in the foot using the Axoguard Nerve Cap are experiencing a reduction in post-operative pain. Additionally, no complications related to the Axoguard Nerve Cap were reported. Future phases of this study will compare pain reduction after neuroma treatment with either the Axoguard Nerve Cap or standard neurectomy.
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