Post-traumatic neuroma due to closed nerve injury. Is recovery after peripheral nerve trauma related to ultrasonographic neuroma size?

• Traumatic neuroma is abnormal regeneration with little known size-related function.
• Neuroma dimension, detectable by ultrasound, may be recovery prognostic factor.
• Huge traumatic neuroma is a negative prognostic factor for functional improvement.

Objectivetraumatic neuroma is a pathological condition of peripheral nervous system consisting of localized proliferation of injured nerve elements. The symptoms depend on the type of involved nerve (motor and/or sensitive) and on the site and the extension of the lesion. Ultrasound is the best tool to depict the morphology of nerve, especially in traumatic conditions. We present a study aimed to assess the correlation between the degree of nerve function and the ultrasound morphology of neuromas.Patients and methodswe retrospectively evaluated 18 patients with neuromas (not transected) occurred after a closed nerve trauma evaluated with clinical and ultrasound assessment. The clinical evaluation was related to the % of increase of cross sectional area as detected by nerve ultrasound respect to normal nerve.Resultswe observed that dimensions of neuromas are not related to function until neuroma have cross sectional area 5 times enlarged respect to normal nerve, in this case recovery never occurs.Conclusionour study failed to clear detect a relation between cross sectional area enlargement of neuroma and nerve function, but showed a cut off beyond which prognosis is negative. This result provide some useful information for prognosis, nevertheless we believe that future perspective studies are needed to better understand the timing of developing neuromas and its evolution.