title: Postoperative expansion of dural sac cross-sectional area after unilateral laminotomy for bilateral decompression: correlation with clinical symptoms.
abstract: OBJECTIVE
  Dural sac cross-sectional area (DSCSA) is a way to measure the degree of central spinal canal compression. The objective was to investigate the correlation between the expansion ratio of DSCSA after unilateral laminotomy for bilateral decompression (ULBD) and the clinical results for lumbar spinal stenosis.
  
  
  METHODS
  We retrospectively reviewed the clinical data and radiographs of 103 patients who underwent ULBD for symptomatic spinal stenosis in one year. We compared preoperative and postoperative clinical data and DSCSA and evaluated the correlation between clinical and radiographic measurements.
  
  
  RESULTS
  There was a significant increase of DSCSA after ULBD (p=0.000) and mean expansion ratio of DSCSA was 203.7±147.2%(range -32.9-826.1%). Clinical outcomes, measured by VAS and ODI were improved significantly not only in early postoperative period, but also in the last follow-up. However, there were no statistically significant correlations between the preoperative DSCSA and clinical symptoms, Perioperative expansion ratio of DSCSA and clinical parameters were also not correlated to the improvement of clinical symptoms significantly in both early postoperative phase and last follow-up.
  
  
  CONCLUSIONS
  Our result indicates that the DSCSA itself has a definite limitation to be correlated to the clinical symptoms, and thus meticulous correlation between the clinical presentation and MRI imaging is essential in determination of surgical treatment.
authors.affiliation: Department of Neurosurgery, Daegu Wooridul Spine Hospital, Daegu, Korea.
authors.forename: Seok-Won
authors.initials: SW
authors.lastname: Chung
authors.affiliation: Department of Neurosurgery, Daegu Wooridul Spine Hospital, Daegu, Korea.
authors.forename: Min-Soo
authors.initials: MS
authors.lastname: Kang
authors.affiliation: Department of Neurosurgery, Daegu Wooridul Spine Hospital, Daegu, Korea.
authors.forename: Yong-Hwan
authors.initials: YH
authors.lastname: Shin
authors.affiliation: Department of Neurosurgery, Daegu Wooridul Spine Hospital, Daegu, Korea.
authors.forename: Oon-Ki
authors.initials: OK
authors.lastname: Baek
authors.affiliation: Department of Neurosurgery, Wooridul Spine Hospital, Seoul, Korea.
authors.forename: Sang-Ho
authors.initials: SH
authors.lastname: Lee
keywords: Laminotomy; Minimally invasive spinal surgery; Radiculopathy; Spinal stenosis