In-hospital mortality rate in subaxial cervical spinal cord injury patients: a systematic review and meta-analysis by Sadeghi-Naini, M, Yousefifard, M, Ghodsi, Z, Azarhomayoun, A, Kermanian, F, Golpayegani, M, Alizadeh, SD, Hosseini, M, Shokraneh, F, Komlakh, K, Vaccaro, AR, Jiang, F, Fehlings, MG, Rahimi-Movaghar, V