title: Clinical characteristics of intraspinal facet cysts following microsurgical bilateral decompression via a unilateral approach for treatment of degenerative lumbar disease.
abstract: OBJECTIVE
  Primary intraspinal facet cysts in the lumbar spine are uncommon, but it is unclear whether cyst incidence increases following decompression surgery and if these cysts negatively impact clinical outcome. We examined the prevalence, clinical characteristics, and the risk factors associated with intraspinal facet cysts after microsurgical bilateral decompression via a unilateral approach (MBDU).
  
  
  METHODS
  We studied 230 patients treated using MBDU for lumbar degenerative disease (133 men and 97 women; mean age 70.3 years). Clinical status, as assessed by the Japanese Orthopedic Association (JOA) score and findings on X-ray and magnetic resonance images, was evaluated prior to surgery and at both 3 months and 1 year after surgery. The prevalence of intraspinal facet cysts was determined and preoperative risk factors were defined by comparing presurgical findings with clinical outcomes.
  
  
  RESULTS
  Thirty-eight patients (16.5%) developed intraspinal facet cysts within 1 year postoperatively, and 24 exhibited cysts within 3 months. In 10 patients, the cysts resolved spontaneously 1 year postoperatively. In total, 28 patients (12.2%) had facet cysts 1 year postoperatively. The mean JOA score of patients with cysts 1 year postoperatively was significantly lower than that of patients without cysts. This poor clinical outcome resulted from low back pain that was not improved by conservative treatment. Most cases with spontaneous cyst disappearance were symptom-free 1 year later. The preoperative risk factors for postoperative intraspinal facet cyst formation were instability (OR 2.47, P = 0.26), scoliotic disc wedging (OR 2.23, P = 0.048), and sagittal imbalance (OR 2.22, P = 0.045).
  
  
  CONCLUSIONS
  Postoperative intraspinal facet cyst formation is a common cause of poor clinical outcome in patients treated using MBDU.
authors.affiliation: Department of Orthopaedic Surgery, Osaka City General Hospital, 2-13-22, Miyakojimahondori, Miyakojima-ku, Osaka, Japan. minorikato@med.osaka-cu.ac.jp
authors.forename: Minori
authors.initials: M
authors.lastname: Kato
authors.forename: Sadahiko
authors.initials: S
authors.lastname: Konishi
authors.forename: Akira
authors.initials: A
authors.lastname: Matsumura
authors.forename: Kazunori
authors.initials: K
authors.lastname: Hayashi
authors.forename: Koji
authors.initials: K
authors.lastname: Tamai
authors.forename: Kosuke
authors.initials: K
authors.lastname: Shintani
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kazuki
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nakamura
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001845:Bone Cysts / Q000000981:diagnostic imaging / Q000453:epidemiology*; D019299:Decompression, Surgical / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008866:Microsurgery / Q000009:adverse effects; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000009:adverse effects; D011184:Postoperative Period; D015995:Prevalence; D011859:Radiography; D012307:Risk Factors; D013122:Spinal Diseases / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome; D021801:Zygapophyseal Joint / Q000000981:diagnostic imaging*
references.citation: J Neurosurg Spine. 2010 Dec;13(6):758-65
references.pmid: 21121755
references.citation: Spine (Phila Pa 1976). 2004 Apr 15;29(8):874-8
references.pmid: 15082987
references.citation: Spine (Phila Pa 1976). 1996 Jan 15;21(2):242-8
references.pmid: 8720411
references.citation: Acta Neurochir (Wien). 1997;139(5):392-6
references.pmid: 9204106
references.citation: J Bone Joint Surg Am. 1979 Jun;61(4):479-95
references.pmid: 438234
references.citation: Spine (Phila Pa 1976). 1999 Nov 1;24(21):2268-72
references.pmid: 10562995
references.citation: Clin Radiol. 1991 Dec;44(6):397-401
references.pmid: 1773558
references.citation: Spine (Phila Pa 1976). 1981 Jul-Aug;6(4):354-64
references.pmid: 6792717
references.citation: J Bone Joint Surg Am. 1985 Jul;67(6):865-71
references.pmid: 4019534
references.citation: Spine (Phila Pa 1976). 2009 Nov 1;34(23):2518-24
references.pmid: 19927101
references.citation: J Neurosurg Spine. 2006 Nov;5(5):398-403
references.pmid: 17120888
references.citation: Spine (Phila Pa 1976). 1995 Jan 1;20(1):80-9
references.pmid: 7709284
references.citation: Spine (Phila Pa 1976). 2001 Apr 15;26(8):969-72
references.pmid: 11317123
references.citation: Acta Neurochir (Wien). 1997;139(5):397-403
references.pmid: 9204107
references.citation: Radiology. 1999 Feb;210(2):509-13
references.pmid: 10207437
references.citation: J Neurosurg Spine. 2008 Dec;9(6):554-9
references.pmid: 19035747
references.citation: J Neurosurg. 2000 Jul;93(1 Suppl):53-7
references.pmid: 10879758
references.citation: Mt Sinai J Med. 1991 Mar;58(2):125-8
references.pmid: 1857355
references.citation: J Neurosurg. 2003 Sep;99(2 Suppl):235-8
references.pmid: 12956468
references.citation: Minim Invasive Neurosurg. 1996 Jun;39(2):45-9
references.pmid: 8811656
references.citation: J Neurosurg Spine. 2009 Jun;10(6):617-22
references.pmid: 19558297
references.citation: Spine (Phila Pa 1976). 2011 Mar 1;36(5):410-5
references.pmid: 20847714
references.citation: AJR Am J Roentgenol. 1987 Jul;149(1):105-7
references.pmid: 3495967
references.citation: Clin Radiol. 1997 Jan;52(1):73-4
references.pmid: 9022588
references.citation: Radiology. 1982 Nov;145(2):375-6
references.pmid: 7134440
references.citation: Neurosurgery. 1995 Aug;37(2):343-7
references.pmid: 7477792
references.citation: Eur Spine J. 2008 Jun;17(6):831-7
references.pmid: 18389295