title: The effectiveness of decompression alone compared with additional fusion for lumbar spinal stenosis with degenerative spondylolisthesis: a pragmatic comparative non-inferiority observational study from the Norwegian Registry for Spine Surgery.
abstract: To evaluate the effect of adding fusion to decompression in patients operated for lumbar spinal stenosis with a concomitant lumbar degenerative spondylolisthesis.
  
  
  
  After propensity score matching, 260 patients operated with decompression and fusion and 260 patients operated with decompression alone were compared. Primary outcome measures were leg and back pain [Numeric Rating Scale (NRS), 0-10] and Oswestry Disability Index (ODI, 0-100) at 12 months.
  
  
  
  At 12-month follow-up, the fusion group rated their pain significantly lower than the decompression alone group [leg pain 3.0 and 3.6, respectively, mean difference -0.6, 95 % confidence interval (CI) -1.2 to -0.05, p = 0.03 and back pain 3.3 and 3.9, respectively, mean difference -0.6, 95 % CI -1.1 to -0.1, p = 0.02]. ODI was not significantly different between the groups (21.0 versus 23.3, mean difference -2.3, 95 % CI -5.8 to 1.1, p = 0.18). Seventy-four percent of the fusion group and 63 % of the decompression alone group achieved a clinically important improvement in back pain (difference in proportion of responders = 11 %, 95 % CI 2-20 %, p = 0.01), corresponding to a number needed to treat of 9 patients (95 % CI 5-50). There was no significant difference in responder rate for leg pain (74 and 67 %, respectively, difference 7 %, 95 % CI -1 to 16 %, p = 0.09) or for ODI (67 and 59 %, respectively, difference 8 %, 95 % CI 0-18 %, p = 0.06). The duration of surgery and hospital stay was longer for the fusion group (mean difference 68 min, 95 % CI 58-78, p < 0.01 and mean difference 4.2 days, 95 % CI 3.5-4.8, p < 0.01).
  
  
  
  In the present non-inferiority study, we cannot conclude that decompression alone is as good as decompression with additional fusion. However, the small differences in the groups' effect sizes suggest that a considerable number of patients can be treated with decompression alone. A challenge in future studies will be to find the best treatment option for each patient.
authors.affiliation: Kysthospitalet in Hagevik, Orthopedic Clinic, Haukeland University Hospital, Bergen, Norway. imau@helse-bergen.no.
authors.forename: Ivar M
authors.initials: IM
authors.lastname: Austevoll
authors.affiliation: Division of Mental Health Care, Haukeland University Hospital, Bergen, Norway.|Centre for Research and Education in Forensic Psychiatry, Haukeland University Hospital, Bergen, Norway.
authors.forename: Rolf
authors.initials: R
authors.lastname: Gjestad
authors.affiliation: Department of Physical Medicine and Rehabilitation, Oslo University Hospital, Oslo, Norway.
authors.forename: Jens Ivar
authors.initials: JI
authors.lastname: Brox
authors.affiliation: Norwegian Registry for Spine Surgery (NORspine), University Hospital of Northern Norway, Tromsø, Norway.|Department of Neurosurgery, University Hospital of Northern Norway, Tromsø, Norway.
authors.forename: Tore K
authors.initials: TK
authors.lastname: Solberg
authors.affiliation: Communication and Research Unit for Musculoskeletal Disorders (FORMI), Oslo University Hospital, University of Oslo, Oslo, Norway.
authors.forename: Kjersti
authors.initials: K
authors.lastname: Storheim
authors.affiliation: Kysthospitalet in Hagevik, Orthopedic Clinic, Haukeland University Hospital, Bergen, Norway.
authors.forename: Frode
authors.initials: F
authors.lastname: Rekeland
authors.affiliation: Kysthospitalet in Hagevik, Orthopedic Clinic, Haukeland University Hospital, Bergen, Norway.|Department of Clinical Medicine, University of Bergen, Bergen, Norway.|Department of Orthopedic Surgery, Ålesund Hospital, Møre and Romsdal Hospital Trust, Ålesund, Norway.
authors.forename: Erland
authors.initials: E
authors.lastname: Hermansen
authors.affiliation: Kysthospitalet in Hagevik, Orthopedic Clinic, Haukeland University Hospital, Bergen, Norway.|Department of Clinical Medicine, University of Bergen, Bergen, Norway.
authors.forename: Kari
authors.initials: K
authors.lastname: Indrekvam
authors.affiliation: Norwegian Registry for Spine Surgery (NORspine), University Hospital of Northern Norway, Tromsø, Norway.|Clinic for Surgery and Neurology, Department of Orthopedics, Oslo University Hospital, University of Oslo, Oslo, Norway.
authors.forename: Christian
authors.initials: C
authors.lastname: Hellum
mesh_terms: D000368:Aged; D019299:Decompression, Surgical; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D007902:Length of Stay; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D009664:Norway; D061646:Operative Time; D010146:Pain / Q000209:etiology / Q000601:surgery; D010147:Pain Measurement; D012042:Registries; D013123:Spinal Fusion; D013130:Spinal Stenosis / Q000601:surgery*; D013168:Spondylolisthesis / Q000601:surgery*
keywords: Degenerative spondylolisthesis; Fusion; Lumbar spinal stenosis; Treatment