title: Can triggered electromyography thresholds assure accurate pedicle screw placements? A systematic review and meta-analysis of diagnostic test accuracy.
abstract: OBJECTIVE
  Triggered electromyography (t-EMG) for pedicle screw placement was introduced to prevent the misplacement of screws; however, its diagnostic value is still debated. This study aimed to clarify the diagnostic value of t-EMG and to compare thresholds.
  
  
  METHODS
  We searched MEDLINE, EMBASE, and the Cochrane Library, and 179 studies were identified. Among them, 11 studies were finally enrolled. The pooled sensitivity, specificity, diagnostic odds ratio (DOR), and summary receiver operating characteristics (SROC) plots were analyzed.
  
  
  RESULTS
  The enrolled studies included 13,948 lumbar and 2070 thoracic screws. The overall summary sensitivity/specificity/DOR values of t-EMG were 0.55/0.97/42.16 in the lumbar spine and 0.41/0.95/14.52 in the thoracic spine, respectively, indicating a weak diagnostic value. However, subgroup analysis by each threshold value showed that the cutoff value of 8mA in the lumbar spine indicated high sensitivity (0.82), specificity (0.97), and DOR (147.95), thereby showing high diagnostic accuracy of identifying misplaced screws.
  
  
  CONCLUSIONS
  The most useful application of t-EMG may be as a warning tool for lumbar pedicle screw malpositioning in the presence of positive stimulation at a threshold of ⩽8mA.
  
  
  CONCLUSIONS
  t-EMG by screw stimulation may be valuable in the lumbar region at a threshold of ⩽8mA.
authors: Department of Neurosurgery, Konyang University Hospital, Konyang University, College of Medicine, Daejeon, Republic of Korea. Electronic address: imspinesurgeon@gmail.com.
authors: Chang-Hyun
authors: CH
authors: Lee
authors: Department of Neurosurgery, Konyang University Hospital, Konyang University, College of Medicine, Daejeon, Republic of Korea.
authors: Hyun-Woo
authors: HW
authors: Kim
authors: Department of Neurosurgery, Konyang University Hospital, Konyang University, College of Medicine, Daejeon, Republic of Korea.
authors: Hong Rye
authors: HR
authors: Kim
authors: Department of Neurosurgery, Konyang University Hospital, Konyang University, College of Medicine, Daejeon, Republic of Korea.
authors: Cheol-Young
authors: CY
authors: Lee
authors: Department of Neurosurgery, Konyang University Hospital, Konyang University, College of Medicine, Daejeon, Republic of Korea.
authors: Jong-Hyun
authors: JH
authors: Kim
authors: Section of Neurosurgery, Department of Neurological and Visual Sciences, University Hospital, Verona, Italy.
authors: Francesco
authors: F
authors: Sala
mesh_terms: D003955:Diagnostic Tests, Routine / Q000379:methods / Q000592:standards*; D004576:Electromyography / Q000379:methods / Q000592:standards*; D006801:Humans; D016343:Monitoring, Intraoperative / Q000379:methods / Q000592:standards*; D065289:Pedicle Screws / Q000592:standards*
keywords: Diagnosis; Electromyograph; Intraoperative; Pedicle screw; Threshold