Phosphorylated neurofilament subunit NF-H becomes elevated in the cerebrospinal fluid of patients with acutely worsening symptoms of compression myelopathy

It is known that the severity of compression myelopathy sometimes worsens rapidly and results in poor functional recovery because of limited axonal regeneration. Levels of phosphorylated neurofilament subunit NF-H (pNF-H), which indicate axonal degeneration, are elevated in other neurological disorders. To our knowledge, there has been no examination of pNF-H levels in compression myelopathy. Therefore, we conducted a pilot cross-sectional study to evaluate pNF-H levels in the cerebrospinal fluid (CSF) of patients with worsening symptoms of cervical compression myelopathy. From January 2011 to March 2013, 51 samples of CSF were collected from patients at the time of myelography before spinal surgery. The indications for surgery were acutely worsening compression myelopathy (AM) in eight, chronic compression myelopathy (CM) in six, and lumbar canal stenosis (LCS) in 37 patients. The pNF-H levels were measured using a standard enzyme-linked immunosorbent assay. The mean ± standard deviation pNF-H value was 2127.1 ± 556.8 pg/ml in AM patients, 175.8 ± 67.38 pg/ml in CM patients and 518.7 ± 665.7 pg/ml in LCS patients. A significant increase in pNF-H levels was detected in the CSF of patients with AM compared with those with either CM or LCS. The clinical outcome of surgical treatment for patients with cervical myelopathy was satisfactory in both AM and CM patients. Despite the limitations of small sample size and lack of healthy CSF control data due to ethical considerations, our results suggest that pNF-H in CSF can act as a biomarker that reflects the severity of AM.