title: Reliability of MRI findings for Symptomatic Extraforaminal Disc Herniation in Lumbar Spine.
abstract: METHODS
  A retrospective study
  
  
  OBJECTIVE
  This study examined the reliability of the MRI findings in detecting symptomatic extraforaminal disc herniation in the lumbar spine.
  
  
  BACKGROUND
  There are no reports of the characteristics and reliable MRI findings of extraforaminal disc herniation.
  
  
  METHODS
  Thirty age-and gender-matched asymptomatic volunteers and 30 patients with symptomatic extraforaminal disc herniation, who underwent surgery between March 2006 and Dec 2008, were enrolled in this study. All subjects underwent spinal MRI. The following parameters were evaluated: the presence or absence of focal eccentricity of the disc, change in the diameter of the nerve root, and displacement of the nerve root at the extraforaminal zones. Radiologic studies were reviewed blindly and independently by 3 spine surgeons.
  
  
  RESULTS
  The overall agreement in determining the presence or absence of a symptomatic extraforaminal disc herniation between the three reviewers was 89.4% (161/180). The consensus showed focal eccentricity of the disc in 33 cases (55%), a change in diameter in the nerve root in 31 cases (51.7%), and a displacement of the nerve root in 23 cases (38.3%). An assessment of the paired intraobserver and interobserver reliability revealed mean Kappa statistics of 0.833 and 0.667 for focal eccentricity of the disc, 0.656 and 0.556 for a change in the diameter of the nerve root, and 0.669 and 0.020 for a displacement of the nerve root, respectively.
  
  
  CONCLUSIONS
  There are three possible MRI findings that can be used to determine the presence or absence of symptomatic extraforaminal disc herniation. Among these MRI findings, focal eccentricity of the disc was found to be the most reliable.
authors.affiliation: Department of Orthopedic Surgery, Busan National University School of Medicine, Busan, Korea.
authors.forename: Kyu Pill
authors.initials: KP
authors.lastname: Moon
authors.forename: Kuen Tak
authors.initials: KT
authors.lastname: Suh
authors.forename: Jung Sub
authors.initials: JS
authors.lastname: Lee
references.citation: J Bone Joint Surg Am. 1971 Jul;53(5):891-903
references.pmid: 4326746
references.citation: AJNR Am J Neuroradiol. 1988 Jul-Aug;9(4):775-8
references.pmid: 3135721
references.citation: Spine (Phila Pa 1976). 1986 Apr;11(3):260-8
references.pmid: 3715625
references.citation: J Neurosurg. 1990 Mar;72(3):378-82
references.pmid: 2303871
references.citation: Spine (Phila Pa 1976). 1988 Jun;13(6):696-706
references.pmid: 3175760
references.citation: J Bone Joint Surg Br. 1997 Nov;79(6):943-7
references.pmid: 9393908
references.citation: AJNR Am J Neuroradiol. 1983 May-Jun;4(3):846-7
references.pmid: 6410869
references.citation: Spine (Phila Pa 1976). 1987 Jul-Aug;12(6):586-9
references.pmid: 3660086
references.citation: AJNR Am J Neuroradiol. 1983 May-Jun;4(3):598-600
references.pmid: 6410807
references.citation: Spine J. 2006 Mar-Apr;6(2):201-3
references.pmid: 16517394
references.citation: Spine (Phila Pa 1976). 2000 Feb 1;25(3):389-94
references.pmid: 10703115
references.citation: J Bone Joint Surg Am. 1985 Oct;67(8):1275-7
references.pmid: 4055853
references.citation: Spine (Phila Pa 1976). 1991 Nov;16(11):1312-20
references.pmid: 1750006
references.citation: J Neurosurg. 1974 Aug;41(2):229-34
references.pmid: 4841878
references.citation: Neurosurgery. 1988 Apr;22(4):648-53
references.pmid: 3374776
references.citation: J Comput Assist Tomogr. 1990 Mar-Apr;14(2):243-9
references.pmid: 2312853
references.citation: Neurosurg Clin N Am. 1993 Jan;4(1):117-24
references.pmid: 8428146
references.citation: Neuroradiology. 1984;26(6):439-44
references.pmid: 6504312
references.citation: Spinal Cord. 1997 Nov;35(11):725-8
references.pmid: 9392041
references.citation: Br J Neurosurg. 1987;1(1):111-29
references.pmid: 3267271