title: Transcranial magnetic stimulation in the semi-quantitative, pre-operative assessment of patients undergoing spinal deformity surgery.
abstract: To compare measurements of motor evoked potential latency stimulated either magnetically (mMEP) or electrically (eMEP) and central motor conduction time (CMCT) made pre-operatively in conscious patients using transcranial and intra-operatively using electrical cortical stimulation before and after successful instrumentation for the treatment of adolescent idiopathic scoliosis.
  
  
  
  A group initially of 51 patients with adolescent idiopathic scoliosis aged 12-19 years was evaluated pre-operatively in the outpatients' department with transcranial magnetic stimulation. The neurophysiological data were then compared statistically with intra-operative responses elicited by transcranial electrical stimulation both before and after successful surgical intervention. MEPs were measured as the cortically evoked compound action potentials of Abductor hallucis. Minimum F-waves were measured using conventional nerve conduction methods and the lower motor neuron conduction time was calculated and this was subtracted from MEP latency to give CMCT.
  
  
  
  Pre-operative testing was well tolerated in our paediatric/adolescent patients. No neurological injury occurred in any patient in this series. There was no significant difference in the values of mMEP and eMEP latencies seen pre-operatively in conscious patients and intra-operatively in patients under anaesthetic. The calculated quantities mCMCT and eCMCT showed the same statistical correlations as the quantities mMEP and eMEP latency.
  
  
  
  The congruency of mMEP and eMEP and of mCMCT and eCMCT suggests that these measurements may be used comparatively and semi-quantitatively for the comparison of pre-, intra-, and post-operative spinal cord function in spinal deformity surgery.
authors.affiliation: Scottish National Spine Deformity Centre, Royal Hospital for Sick Children, Sciennes Road, Edinburgh, EH9 1LF, UK.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Glasby
authors.affiliation: Scottish National Spine Deformity Centre, Royal Hospital for Sick Children, Sciennes Road, Edinburgh, EH9 1LF, UK. atsirikos@hotmail.com.
authors.forename: Athanasios I
authors.initials: AI
authors.lastname: Tsirikos
authors.affiliation: Scottish National Spine Deformity Centre, Royal Hospital for Sick Children, Sciennes Road, Edinburgh, EH9 1LF, UK.
authors.forename: Lindsay
authors.initials: L
authors.lastname: Henderson
authors.affiliation: Scottish National Spine Deformity Centre, Royal Hospital for Sick Children, Sciennes Road, Edinburgh, EH9 1LF, UK.
authors.forename: Gillian
authors.initials: G
authors.lastname: Horsburgh
authors.affiliation: Scottish National Spine Deformity Centre, Royal Hospital for Sick Children, Sciennes Road, Edinburgh, EH9 1LF, UK.
authors.forename: Brian
authors.initials: B
authors.lastname: Jordan
authors.affiliation: Scottish National Spine Deformity Centre, Royal Hospital for Sick Children, Sciennes Road, Edinburgh, EH9 1LF, UK.
authors.forename: Ciara
authors.initials: C
authors.lastname: Michaelson
authors.affiliation: Scottish National Spine Deformity Centre, Royal Hospital for Sick Children, Sciennes Road, Edinburgh, EH9 1LF, UK.
authors.forename: Christopher I
authors.initials: CI
authors.lastname: Adams
authors.affiliation: Scottish National Spine Deformity Centre, Royal Hospital for Sick Children, Sciennes Road, Edinburgh, EH9 1LF, UK.
authors.forename: Enrique
authors.initials: E
authors.lastname: Garrido
mesh_terms: D000293:Adolescent; D002648:Child; D004558:Electric Stimulation; D019054:Evoked Potentials, Motor; D005260:Female; D006801:Humans; D064795:Intraoperative Neurophysiological Monitoring / Q000379:methods*; D008297:Male; D019990:Perioperative Care / Q000379:methods*; D012600:Scoliosis / Q000503:physiopathology / Q000601:surgery*; D050781:Transcranial Magnetic Stimulation; D016896:Treatment Outcome; D055815:Young Adult
keywords: Central motor conduction time; Intra-operative neurophysiological monitoring; Motor evoked potentials; Pre-operative assessment; Spinal deformity; Transcranial magnetic cortical stimulation