title: Risk factors associated with the halo phenomenon after lumbar fusion surgery and its clinical significance.
abstract: METHODS
  Retrospective study.
  
  
  OBJECTIVE
  First, to examine the association between bone mineral density (BMD) and the halo phenomenon, and second, to investigate risk factors predisposing to the halo phenomenon and its correlation with clinical outcomes.
  
  
  BACKGROUND
  The few in vivo studies regarding the relationship between pedicle screw stability and BMD have shown conflicting results.
  
  
  METHODS
  Forty-four female patients who underwent spine fusion surgery due to spinal stenosis were included in this study. The halo phenomenon and fusion state were evaluated through plain radiographs performed immediately after surgery and through the final outpatient follow-up examination. BMD, osteoarthritis grade in the hip and knee joints, and surgical outcome were also evaluated.
  
  
  RESULTS
  BMD was not related to the halo phenomenon, but age, absence of osteoarthritis in the knee, and non-union state were found to be significant risk factors for the halo phenomenon. However, the radiological halo phenomenon did not correlate with clinical outcome (visual analogue scale for back pain and leg pain).
  
  
  CONCLUSIONS
  The halo phenomenon is a simple phenomenon that can develop during follow-up after pedicle screw fixation. It does not influence clinical outcomes, and thus it is thought that hydroxyapatite coating screws, expandable screws, cement augmentation, and additional surgeries are not required, if their purpose is to prevent the halo phenomenon.
authors.affiliation: Department of Orthopedic Surgery, Yonsei University Medical College, Seoul, Korea.
authors.forename: Ho-Joong
authors.initials: HJ
authors.lastname: Kim
authors.forename: Sul-Gee
authors.initials: SG
authors.lastname: Kim
authors.forename: Hwan-Mo
authors.initials: HM
authors.lastname: Lee
authors.forename: Hak-Sun
authors.initials: HS
authors.lastname: Kim
authors.forename: Eun-Su
authors.initials: ES
authors.lastname: Moon
authors.forename: Jin-Oh
authors.initials: JO
authors.lastname: Park
authors.forename: Nam-Heon
authors.initials: NH
authors.lastname: Seol
authors.forename: Seong-Hwan
authors.initials: SH
authors.lastname: Moon
references.citation: Spine (Phila Pa 1976). 1989 Dec;14(12):1398-405
references.pmid: 2617365
references.citation: Spine (Phila Pa 1976). 1991 Jun;16(6):647-52
references.pmid: 1862404
references.citation: Spine (Phila Pa 1976). 1997 Dec 15;22(24 Suppl):43S-48S
references.pmid: 9431644
references.citation: Spine (Phila Pa 1976). 1994 May 15;19(10):1157-61
references.pmid: 8059273
references.citation: Spine (Phila Pa 1976). 1990 Sep;15(9):902-7
references.pmid: 2259978
references.citation: Ann Rheum Dis. 1957 Dec;16(4):494-502
references.pmid: 13498604
references.citation: Spine (Phila Pa 1976). 1992 Mar;17(3 Suppl):S51-4
references.pmid: 1566185
references.citation: Spine (Phila Pa 1976). 1993 Jun 15;18(8):983-91
references.pmid: 8367786
references.citation: J Spinal Disord. 1992 Dec;5(4):433-42
references.pmid: 1490041
references.citation: Spine J. 2001 Nov-Dec;1(6):402-7
references.pmid: 14588296
references.citation: Spine (Phila Pa 1976). 1991 Nov;16(11):1335-41
references.pmid: 1750009
references.citation: Spine (Phila Pa 1976). 1993 Nov;18(15):2231-8; discussion 2238-9
references.pmid: 8278838
references.citation: Spine (Phila Pa 1976). 1993 Dec;18(16):2438-43
references.pmid: 8303446
references.citation: Clin Orthop Relat Res. 1988 Feb;227:99-102
references.pmid: 3338227
references.citation: Spine (Phila Pa 1976). 1993 Nov;18(15):2240-5
references.pmid: 8278839
references.citation: Spine (Phila Pa 1976). 1994 Nov 1;19(21):2415-20
references.pmid: 7846594
references.citation: Spine (Phila Pa 1976). 1991 Mar;16(3 Suppl):S162-9
references.pmid: 2028333
references.citation: Spine (Phila Pa 1976). 1992 Jun;17(6 Suppl):S196-203
references.pmid: 1631718
references.citation: Spine (Phila Pa 1976). 1999 Apr 15;24(8):812-6; discussion 817
references.pmid: 10222534
references.citation: Lancet. 1974 Nov 9;2(7889):1127-31
references.pmid: 4139420
references.citation: Spine (Phila Pa 1976). 1995 Dec 1;20(23):2565-8; discussion 2569
references.pmid: 8610251
references.citation: Spine (Phila Pa 1976). 1997 Jul 1;22(13):1448-53
references.pmid: 9231962