title: Outcome of L5 radiculopathy after reduction and instrumented transforaminal lumbar interbody fusion of high-grade L5-S1 isthmic spondylolisthesis and the role of intraoperative neurophysiological monitoring.
abstract: To evaluate the incidence and course of iatrogenic L5 radiculopathy after reduction and instrumented fusion of high-grade L5-S1 isthmic spondylolisthesis and the role of intraoperative neurophysiological monitoring (IONM).
  
  
  
  Consecutive patients treated for high-grade spondylolisthesis with IONM from 2005 to 2013 were screened for eligibility. Prospectively collected clinical and surgical data as well as radiographic outcomes were analyzed retrospectively. Patients completed the multidimensional Core Outcome Measures Index (COMI) before and at 3, 12, and 24 months after surgery.
  
  
  
  Seventeen patients were included, with a mean age of 26.3 (±9.5) years. Mean preoperative L5-S1 slip was 72% (±21%) and was reduced to 19% (±13%) postoperatively. Mean loss of reduction at last follow-up [mean 19 months (±14, range 3-48 months)] was 3% (±4.3%). Rate of new L5 radiculopathy with motor deficit (L5MD) after surgery was 29% (five patients). Four patients fully recovered after 3 months, one patient was lost to neurologic follow-up. IONM sensitivity and specificity for postoperative L5MD was 20 and 100%, respectively. COMI, back pain and leg pain scores showed significant (p < 0.001) improvements at 3 months postoperatively, which were retained up to 24 months postoperatively.
  
  
  
  Transient L5 radiculopathy after reduction and instrumented fusion of high-grade spondylolisthesis is frequent. With IONM the risk of irreversible L5 radiculopathy is minimal. If IONM signal changes recover, full clinical recovery is expected within 3 months. Overall, patient-reported outcome of reduction and instrumented fusion of high-grade spondylolisthesis showed clinically important improvement.
authors.affiliation: Spine Center, Schulthess Klinik, Lengghalde 2, 8008, Zurich, Switzerland. ralph.schaer@insel.ch.|Department of Neurosurgery, Inselspital, Bern University Hospital, University of Bern, 3010, Bern, Switzerland. ralph.schaer@insel.ch.
authors.forename: Ralph T
authors.initials: RT
authors.lastname: Schär
authors.affiliation: Department of Neurology, Schulthess Klinik, Lengghalde 2, 8008, Zurich, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Sutter
authors.affiliation: Department of Teaching, Research and Development, Schulthess Klinik, Lengghalde 2, 8008, Zurich, Switzerland.
authors.forename: Anne F
authors.initials: AF
authors.lastname: Mannion
authors.affiliation: Department of Teaching, Research and Development, Schulthess Klinik, Lengghalde 2, 8008, Zurich, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Eggspühler
authors.affiliation: Spine Center, Schulthess Klinik, Lengghalde 2, 8008, Zurich, Switzerland.
authors.forename: Dezsö
authors.initials: D
authors.lastname: Jeszenszky
authors.affiliation: Spine Center, Schulthess Klinik, Lengghalde 2, 8008, Zurich, Switzerland.
authors.forename: Tamas F
authors.initials: TF
authors.lastname: Fekete
authors.affiliation: Spine Center, Schulthess Klinik, Lengghalde 2, 8008, Zurich, Switzerland.
authors.forename: Frank
authors.initials: F
authors.lastname: Kleinstück
authors.affiliation: Spine Center, Schulthess Klinik, Lengghalde 2, 8008, Zurich, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Haschtmann
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007049:Iatrogenic Disease; D064795:Intraoperative Neurophysiological Monitoring; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D010147:Pain Measurement; D000071066:Patient Reported Outcome Measures; D011843:Radiculopathy / Q000209:etiology* / Q000517:prevention & control; D020127:Recovery of Function; D012008:Recurrence; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000009:adverse effects* / Q000379:methods; D013168:Spondylolisthesis / Q000601:surgery*; D055815:Young Adult
keywords: Complication; Intraoperative neurophysiological monitoring; Lumbar fusion; Patient-rated outcome; Spondylolisthesis