STUDY DESIGN: A retrospective comparative study. PURPOSE: To clarify the risk factors related to the development of postoperative C5 palsy through radiological studies after cervical double-door laminoplasty (DDL). OVERVIEW OF LITERATURE: Although postoperative C5 palsy is generally considered to be the result of damage to the nerve root or segmental spinal cord, the associated pathology remains controversial. METHODS: A consecutive case series of 47 patients with cervical spondylotic myelopathy treated by DDL at our institution between April 2008 and April 2015 were reviewed. Postoperative C5 palsy occurred in 5 of 47 cases after DDL. We investigated 9 radiologic factors that have been reported to be risk factors for C5 palsy in various studies, and statistically examined these between the two groups of palsy and the non-palsy patients. RESULTS: We found a significant difference between patients with and without postoperative C5 palsy with regards to the posterior shift of spinal cord at C4/5 (p=0.008). The logistic regression analyses revealed posterior shift of the spinal cord at C4/5 (odds ratio, 12.066; p=0.029; 95% confidence interval, 1.295–112.378). For the other radiologic factors, there were no statistically significant differences between the two groups. CONCLUSIONS: In the present study, we showed a significant difference in the posterior shift of the spinal cord at C4/5 between the palsy and the non-palsy groups, indicating that the "tethering phenomenon" was likely a greater risk factor for postoperative C5 palsy.
Humans ; Logistic Models ; Paralysis* ; Pathology ; Retrospective Studies ; Risk Factors* ; Spinal Cord ; Spinal Cord Diseases*

The establishment of enhanced surveillance systems for mass gatherings to detect infectious diseases that may be imported during an event is recommended. The World Health Organization Regional Office for the Western Pacific contributed to enhanced event-based surveillance for the Tokyo 2020 Olympic and Paralympic Games (the Games) by using Epidemic Intelligence from Open Sources (EIOS) to detect potential imported diseases and report them to the National Institute of Infectious Diseases (NIID), Japan. Daily screening of media articles on global infectious diseases was conducted using EIOS, which were systematically assessed to determine the likelihood of disease importation, spread and significant impact to Japan during the Games. Over 81 days of surveillance, 103 830 articles were screened by EIOS, of which 5441 (5.2%) met the selection criteria for initial assessment, with 587 (0.6%) assessed as signals and reported to NIID. None of the signals were considered to pose a significant risk to the Games based on three risk assessment criteria. While EIOS successfully captured media articles on infectious diseases with a likelihood of importation to and spread in Japan, a significant manual effort was required to assess the articles for duplicates and against the risk assessment criteria. Continued improvement of artificial intelligence is recommended to reduce this effort.