Treatment of Iatrogenic Saphenous Neuroma after Knee Arthroscopy with Excision and Muscle Implantation through a Processed Human Nerve Allograft: the “Bridge to Nowhere” Technique
Mathew D Schur, MD, Keck School of Medicine of the University of Southern California, Los Angeles, CA, Rachel Lefebvre, MD, Keck School of Medicine of USC, Los Angeles, CA and Milan Stevanovic, MD, PhD, Orthopaedic Surgery, Keck School of Medicine at USC, Los Angeles, CA
Introduction:
The treatment of post-operative, painful sensory neuromas is an ongoing challenge for surgeons. Neuroma development is unpredictable, the diagnosis often confusing, and treatment techniques and efficacies vary widely. Multiple methods for nerve “capping” or transplantation into a more ameliorative substrate have been described, such as transplantation of excised nerve into neighboring muscle or vein. Here we describe a technique for treatment, the “bridge to nowhere”, and report on its use in treating painful saphenous neuromas after knee arthroscopy.
Materials and Methods:
A retrospective review of a single surgeon's Peripheral Nerve Clinic from January 1st 2013 to June 31st 2019 was conducted to identify post-knee arthroscopy saphenous neuroma cases in which processed human nerve allograft was used as a “bridge to nowhere.” We analyzed demographic and comorbidity data as well as the time from initial arthroscopic surgery to Peripheral Nerve Clinic evaluation and eventual surgical care. We then examined the outcomes for each patient including subjective pain self-assessment and need for further surgical treatment. The surgical technique for the “bridge to nowhere” is as follows: preoperatively the point of maximal pain was marked. An incision of a few centimeters spanning this area was made, and the infrapatellar branch or branches of the saphenous nerve were identified. After identification of the neuroma, it was resected such that only healthy appearing nerve remained. Next, the processed human nerve allograft was sutured to the healthy nerve end using microsurgical technique, fibrin glue applied to the graft site, and the end of the graft embedded in nearby, healthy muscle bed.
Results:
7 cases were identified, with patient ages ranging from 21-69 years. The average time to referral to Peripheral Nerve Clinic was 31 months (range: 4-143 months). Upon exploration, all nerves were found to have a neuroma in continuity. Six of seven patients reported subjective sustained improvement through final follow-up. One out of seven had initial improvement in pain at 1 month, followed by recurrence of her initial neuroma pain. The average follow-up time was 5 months (range: 1-14 mos).
Discussion:
Here we report on a novel technique of using a processed human nerve allograft after neuroma resection to provide an organized environment for “bridging” regenerated axons into muscle tissue. We also describe our experience in using this technique to treat iatrogenic saphenous neuromas after knee arthroscopy. Results are encouraging with six out of seven patients experiencing subjective reduction in pain at final follow-up.
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