title: Minimally invasive resection of lumbar intraspinal synovial cysts via a contralateral approach: review of 13 cases.
abstract: OBJECTIVE
  The authors sought to determine patient-related outcomes after minimally invasive surgical (MIS) lumbar intraspinal synovial cyst excision via a tubular working channel and a contralateral facet-sparing approach.
  
  
  METHODS
  All the patients with a symptomatic lumbar intraspinal synovial cyst who underwent surgery at the University of Iowa Hospitals and Clinics with an MIS excision via a contralateral approach were treated between July 2010 and August 2014. There was a total of 13 cases. Each patient was evaluated with preoperative neurological examinations, lumbar spine radiography, MRI, and visual analog scale (VAS) scores. The patients were evaluated postoperatively with neurological examinations and VAS and Macnab scores. The primary outcomes were improvement in VAS and Macnab scores. Secondary outcomes were average blood loss, hospital stay duration, and operative times.
  
  
  RESULTS
  There were 5 males and 8 females. The mean age was 66 years, and the mean body mass index was 28.5 kg/m(2). Sixty-nine percent (9 of 13) of the cysts were at L4-5. Most patients had low-back pain and radicular pain, and one-third of them had Grade 1 spondylolisthesis. The mean (± SD) follow-up duration was 20.8 ± 16.9 months. The mean Macnab score was 3.4 ± 1.0, and the VAS score decreased from 7.8 preoperatively to 2.9 postoperatively. The mean operative time was 123 ± 30 minutes, with a mean estimated blood loss of 44 ± 29 ml. Hospital stay averaged 1.5 ± 0.7 days. There were no complications noted in this series.
  
  
  CONCLUSIONS
  The MIS excision of lumbar intraspinal synovial cysts via a contralateral approach offers excellent exposure to the cyst and spares the facet joint at the involved level, thus minimizing risk of instability, blood loss, operative time, and hospital stay. Prospective randomized trials with longer follow-up times and larger cohorts are needed to conclusively determine the superiority of the contralateral MIS approach over others, including open or ipsilateral minimally invasive surgery.
authors.affiliation: Department of Neurosurgery, University of Iowa Carver College of Medicine, Iowa City, Iowa.
authors.forename: Hamdi G
authors.initials: HG
authors.lastname: Sukkarieh
authors.affiliation: Department of Neurosurgery, University of Iowa Carver College of Medicine, Iowa City, Iowa.
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Hitchon
authors.affiliation: Department of Neurosurgery, University of Iowa Carver College of Medicine, Iowa City, Iowa.
authors.forename: Olatilewa
authors.initials: O
authors.lastname: Awe
authors.affiliation: Department of Neurosurgery, University of Iowa Carver College of Medicine, Iowa City, Iowa.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Noeller
mesh_terms: D000368:Aged; D016063:Blood Loss, Surgical / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D017116:Low Back Pain / Q000175:diagnosis / Q000601:surgery; D008161:Lumbosacral Region / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D019060:Minimally Invasive Surgical Procedures / Q000379:methods*; D061646:Operative Time; D010147:Pain Measurement; D013168:Spondylolisthesis / Q000175:diagnosis / Q000601:surgery; D013581:Synovial Cyst / Q000175:diagnosis / Q000601:surgery*; D016896:Treatment Outcome
keywords: LISC = lumbar intraspinal synovial cyst; MIS = minimally invasive surgical; MISS = minimally invasive spine surgery; VAS = visual analog scale; contralateral approach; lumbar spine; minimally invasive surgery; synovial cysts