title: Acute Contralateral Radiculopathy after Unilateral Transforaminal Lumbar Interbody Fusion.
abstract: OBJECTIVE
  Cases of contralateral radiculopathy after a transforaminal lumbar interbody fusion with a single cage (unilateral TLIF) had been reported, but the phenomenon has not been explained satisfactorily. The purpose of this study was to determine its incidence, causes, and risk factors.
  
  
  METHODS
  We did retrospective study with 546 patients who underwent a unilateral TLIF, and used CT and MRI to study the causes of contralateral radicular symptoms that appeared within a week postoperatively. Clinical and radiological results were compared by dividing the patients into the symptomatic group and asymptomatic group.
  
  
  RESULTS
  Contralateral symptoms occurred in 32 (5.9%) of the patients underwent unilateral TLIF. The most common cause of contralateral symptoms was a contralateral foraminal stenosis in 22 (68.8%), screw malposition in 4 (12.5%), newly developed herniated nucleus pulposus in 3 (9.3%), hematoma in 1 (3.1%), and unknown origin in 2 patients (6.3%). 16 (50.0%) of the 32 patients received revision surgery. There was no difference in visual analogue scale and Oswestry disability index between the two groups at discharge. Both preoperative and postoperative contralateral foraminal areas were significantly smaller, and postoperative segmental angle was significantly greater in the symptomatic group comparing to those of the asymptomatic group (p<0.05).
  
  
  CONCLUSIONS
  The incidence rate is not likely to be small (5.9%). If unilateral TLIF is performed for cases when preoperative contralateral foraminal stenosis already exists or when a large restoration of segmental lordosis is required, the probability of developing contralateral radiculopathy is increased and caution from the surgeon is needed.
authors.affiliation: Department of Neurosurgery, College of Medicine, Chung-Ang University, Seoul, Korea.
authors.forename: Kyoung-Min
authors.initials: KM
authors.lastname: Jang
authors.affiliation: Department of Neurosurgery, College of Medicine, Chung-Ang University, Seoul, Korea.
authors.forename: Seung-Won
authors.initials: SW
authors.lastname: Park
authors.affiliation: Department of Neurosurgery, College of Medicine, Chung-Ang University, Seoul, Korea.
authors.forename: Young-Baeg
authors.initials: YB
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, College of Medicine, Chung-Ang University, Seoul, Korea.
authors.forename: Yong-Sook
authors.initials: YS
authors.lastname: Park
authors.affiliation: Department of Neurosurgery, College of Medicine, Chung-Ang University, Seoul, Korea.
authors.forename: Taek-Kyun
authors.initials: TK
authors.lastname: Nam
authors.affiliation: Department of Neurosurgery, College of Medicine, Chung-Ang University, Seoul, Korea.
authors.forename: Young-Seok
authors.initials: YS
authors.lastname: Lee
keywords: Complication; Lordosis; Lumbar manipulation; Radiculopathy; Spinal stenosis