Abstract
Study design
Exploratory research
Objectives
Cutaneous silent periods (CSPs) that reflect the inhibitory spinal cord reflex, can sensitively detect spinal cord dysfunction, and contribute to the diagnosis of degenerative cervical myelopathy (DCM). However, CSP changes after DCM surgery related to functional improvement have not been reported.
Setting
University hospital in Nankoku, Japan
Methods
CSP recorded at four time points—before surgery, 3, 6, 12 months after surgery—were investigated in 31 hands of 16 DCM patients. CSPs were categorized as follows: normal, delayed onset latency, shortened duration, onset delay with shortened duration, and absent CSP. Myelopathic symptoms were evaluated by the Japanese Orthopaedic Association score (JOA score).
Results
Normal CSPs were observed in five hands (16%) before surgery and six hands (19%) twelve months after surgery (P > 0.05). Either onset delay or shortened duration or both were observed in 18 hands (58%) before surgery and 16 hands (52%) twelve months after surgery (P > 0.05). Absent CSPs were observed in eight hands (26%) before surgery and nine hands (29%) twelve months after surgery (P > 0.05). Measured values of onset latency and duration also did not change throughout the study period (P > 0.05). On the other hand, JOA scores improved after surgery. (P = 0.003).
Conclusions
CSP abnormalities persisted after surgery in most cases, indicating irreversible damage of the intramedullary reflex circuit. JOA score recovery without CSP recovery provides insight into postoperative neural recovery in DCM.
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Data archiving
The datasets generated and/or analyzed during the current study are available from the corresponding author upon request.
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NT contributed to the planning of this research project, data collection, data analysis and was the main author of this manuscript. KK, YK, MK, RT and MI contributed to the planning of the project, data analysis and revision of the manuscript.
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The participants in this prospective study provided informed consent, and this study was approved by the institutional review board (study no. ERB-102734).
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Tadokoro, N., Kiyasu, K., Kasai, Y. et al. Discrepancy between functional recovery and cutaneous silent period change in surgically treated degenerative cervical myelopathy: a prospective pilot study. Spinal Cord 57, 1076–1083 (2019). https://doi.org/10.1038/s41393-019-0314-0
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DOI: https://doi.org/10.1038/s41393-019-0314-0
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