title: Cervical spinal canal stenosis first presenting after spinal cord injury due to minor trauma: An insight into the value of preventive decompression.
abstract: OBJECTIVE
  Patients with pre-existing cervical spinal canal stenosis (CSCS) may have minimal or no symptoms. However, performing preventive decompression is controversial as the incidence of CSCS leading to severe cord injury is unknown. Hence, this study aims to revisit the threshold for surgery in "silent" CSCS by reviewing the neurologic outcomes of patients with undiagnosed CSCS who sustained a cervical spinal cord injury (CSCI).
  
  
  METHODS
  Two groups of subjects were recruited for analysis. Firstly, patients with trauma-induced CSCI without fracture or dislocation were included. Pre-existing CSCS was diagnosed by MRI measurements. The second group consisted of asymptomatic subjects recruited from the general population who also had MRIs performed. Canal sizes were compared between this control group and the patient group. Within the patient group, neurological assessments and outcomes by Frankel classification were performed in patients treated surgically or conservatively.
  
  
  RESULTS
  32 patients with CSCS were recruited. The mean spinal canal sagittal diameter (disc-level) of all CSCS cases was 5.3 ± 1.4 mm (1.3-8.2). In comparison, the diameter was 10.5 ± 1.7 mm (6.6-14.6) in the 47 asymptomatic individuals recruited from the general population. Decompression was performed in 17 patients and conservative treatment in 15. Mean follow-up was 19.3 ± 17.0 months (6-84). At the final follow-up, 3 patients (9.3%) returned to their pre-injury Frankel grade, whereas 26 patients (83.3%) lost one or more neurological grade. Three patients (9.3%) died.
  
  
  CONCLUSIONS
  Majority of patients with "silent" CSCS who sustained cervical cord injuries did not return to their pre-injury neurological status. All of these subjects have pre-existing canal stenosis hence the risk of cord injury. Given the poor neurological outcome of CSCS, a lower threshold for surgery could be indicated to avoid these disastrous injuries. However, before making any conclusive recommendation we must first identify the prevalence of "silent" CSCS in the general population and the risk of developing spinal cord injury with more prospective population-based studies.
authors.affiliation: Department of Orthopaedics and Traumatology, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China; Department of Orthopaedic Surgery, Nara Medical University, Nara, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Shigematsu
authors.affiliation: Department of Orthopaedics and Traumatology, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China.
authors.forename: Jason Pui Yin
authors.initials: JP
authors.lastname: Cheung
authors.affiliation: Department of Orthopaedics and Traumatology, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China.
authors.forename: Kin-Cheung
authors.initials: KC
authors.lastname: Mak
authors.affiliation: Department of Orthopaedics, Hospital Español Central, Buenos Aires, Argentina.
authors.forename: Mauro
authors.initials: M
authors.lastname: Bruzzone
authors.affiliation: Department of Orthopaedics and Traumatology, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China. Electronic address: hrmoldk@hku.hk.
authors.forename: Keith D K
authors.initials: KD
authors.lastname: Luk
mesh_terms: D000328:Adult; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D015331:Cohort Studies; D000072700:Conservative Treatment / Q000379:methods; D019299:Decompression, Surgical / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D033162:Incidental Findings; D015601:Injury Severity Score; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D011322:Primary Prevention / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D013119:Spinal Cord Injuries / Q000000981:diagnostic imaging* / Q000601:surgery*; D013130:Spinal Stenosis / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome