Abstract
Objective: Syrinx formation is estimated to occur in 20–25% patients after spinal cord injury. Aim of this study was to analyse the factors affecting the formation of post-traumatic syrinx.
Design: Retrospective study of 295 patients with spinal cord injury treated in a spinal injury centre with a minimum follow-up of two years since injury. Patient notes, x-rays and scans were reviewed.
Subjects: Two hundred and fifty-two men and 43 women were included in the study. The spinal injury was treated non-operatively in 172 (M 144, F28) patients and surgically in 123 (M 108, F 15) patients. Average age at the time of injury was 28.2 years. Mean follow-up was 6.4 years (2–34). There were 98 cervical, 134 thoracic and 73 lumbar and thoracolumbar injuries.
Outcome Measures: The incidence of post-traumatic syrinx in both groups and its relationship with level and type of skeletal injury, severity of spinal cord injury, sagittal angle at the injury level were assessed.
Results: In total 59 (20%) patients were identified with post-traumatic syrinx. Of the 123 patients managed operatively 15 (12.2%) had syrinx as did 44 (25.6%) of the 172 patients treated conservatively (p=0.001). Twenty-one (21.4%) cervical injuries, 29 (21.6%) thoracic injuries and nine (12.3%) lumbar injuries were found to have syrinx (p=0.023). Twenty-seven (46%) patients with syrinx had complete cord injury as did 130 (55%) patients who did not have syrinx (p=0.112). Fracture-dislocation was the injury most commonly associated with post-traumatic syrinx. Of the 40 `patients who had fracture dislocation as original injury, syrinx developed in 16 (40%). Eleven of the 18 patients with conservatively managed fracture dislocation, developed syrinx, compared to five of the 32 operatively treated fracture dislocations (p=0.0001). The mean sagittal angle at the level of injury was 25.2° in those syrinx formation, 20.4° in the conservatively treated patients without syrinx (p=0.1191) and 15.32° in the surgically treated patients without syrinx (p=0.016).
Conclusions: In a series of 295 patients, post-traumatic syrinx formation was found in 20% cases. It was significantly more common in patients treated conservatively, especially if the original injury was fracture dislocation. Syrinx formation was also significantly more common in cervical and thoracic cord injuries, but had no association with the completeness of cord injury. In the sagittal plane there was significantly more kyphotic deformity in those with syrinx formation.
The abstracts were prepared by Mr Peter Millner. Correspondence should be addressed to Peter Millner, Consultant Spinal Surgeon, Orthopaedic Surgery, Chancellor Wing, Ward 28 Office Suite, St James’ University Hospital, Beckett Street, Leeds LS9 7TF.
