title: Minimally invasive surgery for lumbar synovial cysts with coexisting degenerative spondylolisthesis.
abstract: BACKGROUND
  About one third of lumbar synovial cysts are associated with degenerative spondylolisthesis. Segmental instability is thought to contribute to the pathogenesis and recurrence of synovial cysts and lumbar fusion has been advocated as a treatment of choice in the presence of spondylolisthesis. In patients with spondylolisthesis, minimally invasive resection of lumbar synovial cysts, without fusion, could minimize surgically induced segmental instability while providing good pain relief.
  
  
  METHODS
  Clinical and radiological outcomes of lumbar synovial cyst patients with and without spondylolisthesis were retrospectively compared. Pain outcomes were assessed with modified Macnab criteria.
  
  
  RESULTS
  Fifty-three patients (18 with grade 1 spondylolisthesis) underwent minimally invasive synovial cyst resection and all had either excellent or good pain outcome at ≤ 8 post- operative weeks (P = 1.000, n = 53). At > 8 post-operative weeks (mean (SD) follow-up of 200 (175) weeks), excellent or good outcomes were noted in 89% of patients without spondylolisthesis and in 75% of patients with spondylolisthesis (P = 0.425, n = 40). Four patients developed a new grade 1 spondylolisthesis at a mean follow-up of 2.6 ± 2.1 years. Nine patients were assessed for spondylolisthesis measurements at 1.2 ± 1.3 years of follow up and no significant difference was observed (5 ± 0 vs 5 ± 1 mm; P = 0.791). Two patients without spondylolisthesis and none of the patients with spondylolisthesis had a synovial cyst recurrence.
  
  
  CONCLUSIONS
  Patients with concomitant lumbar degenerative spondylolisthesis and synovial cyst can have good short- and long-term clinical outcomes with minimally invasive surgery without fusion. Post-operative segmental instability does not appear to be significant in patients with spondylolisthesis. All patients included in this article signed an informed consent for the use of their medical information for research.
authors.affiliation: Department of Neurosurgery, Ochsner Medical Center, New Orleans, LA, USA.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Denis
authors.affiliation: Department of Neurosurgery, University of California, Los Angeles, CA, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Hirt
authors.affiliation: Department of Neurosurgery, University of California, Los Angeles, CA, USA.
authors.forename: Saumya
authors.initials: S
authors.lastname: Shah
authors.affiliation: Department of Neurosurgery, University of California, Los Angeles, CA, USA.
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Lu
authors.affiliation: Department of Neurosurgery, University of California, Los Angeles, CA, USA.
authors.forename: Langston T
authors.initials: LT
authors.lastname: Holly
keywords: minimally invasive surgery; outcomes; spondylolisthesis; synovial cyst