title: Vertebral Distraction during Anterior Cervical Discectomy and Fusion Causes Postoperative Neck Pain.
abstract: OBJECTIVE
  Vertebral distraction is routinely performed during anterior cervical discectomy and fusion (ACDF). Overdistraction can injure the facet joints and may cause postoperative neck pain consequently. The purpose of this study was to investigate the clinical relevance of distraction force during ACDF.
  
  
  METHODS
  This study included 24 consecutive patients with single level cervical disc disease undergoing single level ACDF. We measure the maximum torque just before the the arm of the Caspar retractor was suspended by the rachet mechanism by turning the lever on the movable arm using a torque meter. In order to turn the lever using the torque driver, we made a linear groove on the top of the lever. We compared the neck disability index (NDI) and visual analogue scale (VAS) scores between the high torque group (distraction force>6 kgf·cm) and the low torque group (distraction force≤6 kgf·cm) at routine postoperative intervals of 1, 3, 5 days and 1, 3, 6 months.
  
  
  RESULTS
  The VAS scores for posterior neck pain had a linear correlation with torque at postoperative 1st and 3rd days (y=0.99×-1.1, r(2)=0.82; y=0.77×-0.63, r(2)=0.73, respectively). VAS scores for posterior neck pain were lower in the low torque group than in the high torque group on both 1 and 3 days postoperatively (3.1±1.3, 2.6±1.0 compared with 6.0±0.6, 4.9±0.8, p<0.01). However, the difference in NDI scores was not statistically significant in all postoperative periods.
  
  
  CONCLUSIONS
  Vertebral distraction may cause posterior neck pain in the immediate postoperative days. We recommend not to distract the intervertebral disc space excessively with a force of more than 6.0 kgf·cm.
authors.affiliation: Department of Neurosurgery, CHA University, Pocheon, Korea.
authors.forename: Seung Man
authors.initials: SM
authors.lastname: Ha
authors.forename: Jeong Hoon
authors.initials: JH
authors.lastname: Kim
authors.forename: Seung Hun
authors.initials: SH
authors.lastname: Oh
authors.forename: Ji Hwan
authors.initials: JH
authors.lastname: Song
authors.forename: Hyoung Ihl
authors.initials: HI
authors.lastname: Kim
authors.forename: Dong Ah
authors.initials: DA
authors.lastname: Shin
keywords: Cervical spine; Postoperative pain; Spinal fusion; Zygapophyseal joint
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