CLINICAL ARTICLE J Neurosurg Spine 26:668–678, 2017 ABBREVIATIONS CSM = cervical spondylotic myelopathy; M1 = primary motor cortex; mJOA = modified Japanese Orthopaedic Association; mJOA-LE = mJOA lower- extremity motor domain; mJOA-UE = mJOA upper-extremity sensorimotor domain; MRS = MR spectroscopy; NAA = N-acetylaspartate; SCI = spinal cord injury; 1 H-MRS = proton MRS; 9-HPT = 9-hole peg test. SUBMITTED April 27, 2016. ACCEPTED October 31, 2016. INCLUDE WHEN CITING Published online March 17, 2017; DOI: 10.3171/2016.10.SPINE16479. Remote motor system metabolic profle and surgery outcome in cervical spondylotic myelopathy Sorin C. Craciunas, MD, PhD, 1 Mircea R. Gorgan, MD, 1 Bogdan Ianosi, MD, 2,3 Phil Lee, PhD, 4 Joseph Burris, MD, 6 and Carmen M. Cirstea, MD, PhD 5,6 1 Department of Neurosurgery, Bagdasar-Arseni Hospital, Bucharest, Romania; 2 Department of Neurology, Elbe Kliniken Hospital, University Medical Center Hamburg-Eppendorf, Germany; 3 Romanian National Institute of Neurology and Neurovascular Diseases, Bucharest, Romania; Departments of 4 Molecular and Integrative Physiology and 5 Neurology, Kansas University Medical Center, Kansas City, Kansas; and 6 Department of Physical Medicine & Rehabilitation, University of Missouri, Columbia, Missouri OBJECTIVE In patients with cervical spondylotic myelopathy (CSM), the motor system may undergo progressive func- tional/structural changes rostral to the lesion, and these changes may be associated with clinical disability. The extent to which these changes have a prognostic value in the clinical recovery after surgical treatment is not yet known. In this study, magnetic resonance spectroscopy (MRS) was used to test 2 primary hypotheses. 1) Based on evidence of corti- cospinal and spinocerebellar, rubro-, or reticulospinal tract degeneration/dysfunction during chronic spinal cord compres- sion, the authors hypothesized that the metabolic profle of the primary motor cortices (M1s) and cerebellum, respective- ly, would be altered in patients with CSM, and these alterations would be associated with the extent of the neurological disabilities. 2) Considering that damage and/or plasticity in the remote motor system may contribute to clinical recovery, they hypothesized that M1 and cerebellar metabolic profles would predict, at least in part, surgical outcome. METHODS The metabolic profle, consisting of N-acetylaspartate (NAA; marker of neuronal integrity), myo-inositol (glial marker), choline (cell membrane synthesis and turnover), and glutamate-glutamine (glutamatergic system), of the M1 hand/arm territory in each hemisphere and the cerebellum vermis was investigated prior to surgery in 21 patients exhibiting weakness of the upper extremities and/or gait abnormalities. Age- and sex-matched controls (n = 16) were also evaluated to estimate the pre-CSM metabolic profle of these areas. Correlation and regression analyses were per- formed between preoperative metabolite levels and clinical status 6 months after surgery. RESULTS Relative to controls, patients exhibited signifcantly higher levels of choline but no difference in the levels of other metabolites across M1s. Cerebellar metabolite levels were indistinguishable from control levels. Certain me- tabolites—myo-inositol and choline across M1s, NAA and glutamate-glutamine in the left M1, and myo-inositol and glutamate-glutamine in the cerebellum—were signifcantly associated with postoperative clinical status. These associa- tions were greatly improved by including preoperative clinical metrics into the models. Likewise, these models improved the predictive value of preoperative clinical metrics alone. CONCLUSIONS These preliminary fndings demonstrate relationships between the preoperative metabolic profles of two remote motor areas and surgical outcome in CSM patients. Including preoperative clinical metrics in the models signifcantly strengthened the predictive value. Although further studies are needed, this investigation provides an im- portant starting point to understand how the changes upstream from the injury may infuence the effect of spinal cord decompression. https://thejns.org/doi/abs/10.3171/2016.10.SPINE16479 KEY WORDS cervical spondylotic myelopathy; 1 H-MRS; remote motor system; neuroinflammation; clinical outcome; spinal decompression surgery ©AANS, 2017 J Neurosurg Spine Volume 26 • June 2017 668 Unauthenticated | Downloaded 11/29/21 07:38 PM UTC