title: Variation in selection criteria and approaches to surgery for Lumbar Spinal Stenosis among patients treated in Boston and Norway.
abstract: OBJECTIVE
  There are no uniform guidelines regarding when to operate or the ideal surgical intervention in Lumbar Spinal Stenosis (LSS). Understanding the presence of practice-based variation between different localities is critical. We sought to compare patient-reported pre-operative pain, disability, and health-related quality of life as indications for surgery between Boston and Norway, and the use of decompression alone vs. decompression and arthrodesis.
  
  
  METHODS
  This study included 3826 patients; 1886 from Boston and 1940 from Norway. Eligible patients were 50 years or older who received surgery for the diagnosis of LSS. Data were retrieved from a centralized clinical database in Boston and a national spine registry in Norway based on reported diagnosis and procedure. We evaluated patient-reported pre-operative pain, disability, and health-related quality of life as indications for surgery. A propensity score match was performed for the generation of comparable cohorts.
  
  
  RESULTS
  There were no significant differences in demographics between the unadjusted cohorts. The rates of obesity (39.4% vs. 25.4%; p<0.001) and patients with ASA ≥3 (34.8% vs. 22.1%; p<0.001) were higher in the Boston cohort, while smokers were less frequent (9.6% vs. 19.3%; p<0.001). These differences were accounted for in the propensity score matching. Pre-operative ODI was slightly higher among patients in Boston (43.3 [95% CI 41.5, 45.1] vs. 40.7 [95% CI 40.0, 41.4]; p=0.005), but did not reach the minimal clinically important difference. No statistical difference was encountered between pre-operative EQ-5D (0.339 [95% CI 0.304, 0.374] vs. 0.366 [95% CI 0.351, 0.381]; p=0.16). Fifty-one percent of patients treated in Boston received a decompression and arthrodesis, as compared to only 13.9% of those in Norway (p<0.001). In the matched cohort, counting 294 in each group, the overall conclusions were the same.
  
  
  CONCLUSIONS
  The results demonstrate that indications for intervention were very similar in comparable patient populations with LSS in Boston and Norway. The use of supplemental arthrodesis was significantly greater in Boston. The etiology behind this finding is likely multifactorial but may represent medico-legal concerns in the US, or the phenomenon of provider inducement.
authors.affiliation: Department of Orthopaedics, Innlandet Hospital Trust, Anders Sandvigsgate 17, 2629 Lillehammer, Norway. Electronic address: gloenne@mac.com.
authors.forename: Greger
authors.initials: G
authors.lastname: Lønne
authors.affiliation: Department of Orthopaedic Surgery, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St., Boston, MA 02115, USA. Electronic address: ajschoen@neomed.edu.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Schoenfeld
authors.affiliation: Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St., Boston, MA 02214, USA.
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Cha
authors.affiliation: Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St., Boston, MA 02214, USA; Center for Spinal Disorders, Department of Neurosurgery, St Olav's University Hospital, Trondheim, Norway.
authors.forename: Øystein P
authors.initials: ØP
authors.lastname: Nygaard
authors.affiliation: FORMI, Communication Unit for Musculoskeletal Disorders, Oslo University Hospital, Ullevaal, Oslo, Norway.
authors.forename: John Anker H
authors.initials: JAH
authors.lastname: Zwart
authors.affiliation: Department of Ophthalmology and Neurosurgery, University Hospital of Northern Norway, The Norwegian Registry for Spine Surgery (NORspine), Northern Norway Regional Health Authority, Tromsø, Norway.
authors.forename: Tore
authors.initials: T
authors.lastname: Solberg
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001174:Arthrodesis; D001900:Boston; D015331:Cohort Studies; D019299:Decompression, Surgical; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008161:Lumbosacral Region / Q000601:surgery; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D009664:Norway; D009765:Obesity / Q000453:epidemiology; D010147:Pain Measurement; D018579:Patient Selection; D057216:Propensity Score; D011788:Quality of Life; D012042:Registries; D012189:Retrospective Studies; D013130:Spinal Stenosis / Q000150:complications / Q000601:surgery*; D016896:Treatment Outcome
keywords: Lumbar spine stenosis; Regional variation; Surgical indications