1351. Etiology of Peripheral Neuropathy in Neurofibromatosis 2

Award: First Place Peripheral Nerve Eposter Award

Authors: Rogelio Medina; Dominic Maggio, MD, MBA; Joseph Antonios, PhD; Tanya Lehky; Gretchen Scott; Sarah Benzo; Christina Hayes; Gautam Mehta, MD; John Heiss, MD; Prashant Chittiboina, MD, MPH (Bethesda, CA)

 

Introduction

Neurofibromatosis-2 (NF2) predisposes patients to the development of central and peripheral neuropathies. NF2 patients often present with symptoms of neuropathy due to either polyradicular axonal pathology or from enlarging schwannomas causing compression of peripheral nerves. Differentiating between the two is critical prior to offering surgical treatment. Here, we sought to understand the pathophysiologic basis of peripheral neuropathy in NF2.

 

Methods

We analyzed clinical, neurophysiology and imaging data of 168 patients enrolled in a natural history of NF2 trial at the NIH Clinical Center, Bethesda, MD between 2005-2018.

 

Results

Forty NF2 patients (24F) presented with symptoms suggestive of new/worse peripheral neuropathy in 60 unique clinical visits. Patients presented with local pain (80%) or weakness (53.3%), sensory loss (48.3%), and paresthesias (45%) along the parent nerve distribution. Following 26 visits, unequivocal presenting symptoms and clinical exam led to surgical resection of offending schwannomas. Following 34 visits, EMG/NCV studies were performed to guide further management. Of these, schwannoma resection followed in 22 cases, and conservative management recommended in 14. Polyradicular axonal neuropathy was detected in 11/40 (27.5%) of patients.  Overall, 48 surgeries (22 with intra-operative-neuromonitoring) were performed to remove 64 schwannomas. At 6-months, presenting symptoms were not evaluated formally in 7/48 instances. In the rest, an improvement in presenting symptoms was noted in all, with complete resolution of presenting symptoms noted in 29/41 (70.7%). Overall, EMG/NCV findings resulted in 14 fewer surgeries in this series.

 

Conclusion

We found that patients with NF2 present with neuropathy related to peripheral nerve schwannomas as well as unexplained EMG/NCV findings. In instances of distinct schwannoma growth along peripheral nerves, nerve fascicle sparing surgical resection leads to resolution of neuropathic symptoms. EMG/NCV studies and imaging helps guide the management of NF2 patients with high degree of certainty.