Broadening the spectrum of controls for skin biopsy in painful neuropathies: spondylotic cervical myelopathy patients with painful feet

PURPOSE: Intraepidermal nerve fiber density (IENFD) is useful in the evaluation of small‐fiber neuropathy (SFN). Recent guidelines recommend extending the spectrum of controls for IENFD assessment by evaluation of patients whose clinical picture mimics that of SFN. The aim of this study was to broaden the spectrum of IENFD controls by the assessment of patients with cervical spondylotic myelopathy (CSM) and painful feet. METHODS: Evaluation of IENFD from skin biopsy samples and quantitative sensory testing (QST) were performed in a cohort of 14 CSM patients (eight men, median age: 58; range: 46–63 years), with painful feet, exhibiting no clinical or electrophysiological signs of large‐fiber polyneuropathy, and no risk factors for peripheral neuropathies. RESULTS: Quantitative sensory testing abnormalities were found in all but two of the CSM patients (86%), while the IENFD values were within reference range. The mean IENFD value (6.87 ± 2.78 fibers/mm) did not differ from that of an age‐ and sex‐matched cohort of healthy volunteers (7.97 ± 2.21 fibers/mm, P > 0.05). CONCLUSIONS: The study confirmed normal skin biopsy findings in patients with CSM as one of the clinical conditions mimicking SFN and provided further support for the use of IENFD assessment in case of suspicion of SFN.