Is Surfer's myelopathy an acute hyperextension-induced myelopathy? A systematic synthesis of case studies and proposed diagnostic criteria

Background Surfer's myelopathy is a rare complication of spinal hyperextension originally described in novice surfers. However, reports from patients practicing different activities had risen. Aim To systematically synthesize the epidemiological and clinical evidence on acute hyperextension-induced myelopathy ("Surfer's myelopathy") and propose new diagnostic criteria. Methods We systematically searched four databases for all observational and case studies on the topic. We performed a narrative synthesis to propose diagnostic criteria and tested the criteria retrospectively on the included cases. A case report is also presented. Results Forty-two articles reporting 104 cases (median age 19 years, slightly male predominance) were included. All cases reported a nontraumatic hyperextension event (58% after surfing). All of the cases presented pain of hyperacute onset. The most frequent clinical feature was bladder or bowel dysfunction (84%). The thoracic region was the most frequently affected (87%) with longitudinal involvement until the conus (67%). At discharge or follow-up, 52% partially recovered. We propose five diagnostic criteria with three levels of certainty (definite, probable, and possible): (1) nontraumatic spine hyperextension activity (in individuals with no pre-existent spinal disease); (2) hyperacute onset (with acute pain onset); (3) spinal cord injury clinic (motor, sensory, or autonomic deficit); (4) MRI findings with central spinal cord abnormalities (multiple segments); and (5) no other alternative diagnosis. We identified 88% definite and 12% probable/possible cases. Conclusion The acute hyperextension-induced myelopathy could occur not only during surfing but also during other activities. Therefore, increased awareness and education among sports communities and general physicians are needed.