title: Factors associated with improvement in sagittal spinal alignment after microendoscopic laminotomy in patients with lumbar spinal canal stenosis.
abstract: OBJECTIVE Little is known about the relationship between sagittal spinal alignment in patients with lumbar spinal canal stenosis (LSS) and objective findings such as spinopelvic parameters, lumbar back muscle degeneration, and clinical data. The purpose of this study was to identify the preoperative clinical and radiological factors that predict improvement in sagittal spinal alignment after decompressive surgery in patients with LSS. METHODS The records of 61 patients with LSS who underwent microendoscopic laminotomy and had pre- and postoperative clinical data collected were retrospectively reviewed. Spinopelvic parameters, including sagittal vertical axis (SVA), lumbar lordosis (LL), sacral slope, pelvic tilt, and pelvic incidence (PI), were evaluated. On T2-weighted MRI, the cross-sectional area and the percentage of fat infiltration of the paravertebral muscles (PVMs) before surgery were calculated. For patients with preoperative SVA > 40 mm (n = 30), the correlation between SVA improvement and preoperative clinical and radiographic parameters was calculated. RESULTS SVA improvement correlated with preoperative LL (r = -0.39) and PI -LL (r = 0.54). Multiple regression analysis showed that preoperative PI -LL (beta = 0.62; p < 0.01) and symptom duration (beta = -0.40; p < 0.05) were independently associated with SVA improvement. The percentage of fat infiltration of the PVM at L4-5 was significantly greater in patients with preoperative SVA ≥ 40 mm than in those patients with SVA < 40 mm. CONCLUSIONS Preoperative PI -LL and symptom duration were independently associated with SVA improvement in LSS patients with forward-bending posture. PVM degeneration at the lower lumbar level was significantly greater among patients with preoperative SVA ≥ 40 mm than in patients with SVA < 40 mm.
authors.affiliation: Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka;
authors.forename: Sho
authors.initials: S
authors.lastname: Dohzono
authors.affiliation: Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka;
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Toyoda
authors.affiliation: Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka;
authors.forename: Shinji
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: Department of Orthopaedic Surgery, Osaka Rosai Hospital, Osaka, Japan.
authors.forename: Tomiya
authors.initials: T
authors.lastname: Matsumoto
authors.affiliation: Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka;
authors.forename: Akinobu
authors.initials: A
authors.lastname: Suzuki
authors.affiliation: Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka;
authors.forename: Hidetomi
authors.initials: H
authors.lastname: Terai
authors.affiliation: Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka;
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nakamura
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019299:Decompression, Surgical / Q000379:methods*; D004724:Endoscopy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007796:Laminectomy / Q000379:methods*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008866:Microsurgery / Q000379:methods*; D008875:Middle Aged; D011379:Prognosis; D012044:Regression Analysis; D012189:Retrospective Studies; D013130:Spinal Stenosis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome
keywords: %FI = percentage of fat infiltration; C-7 plumb line; CSA = cross-sectional area; JOA = Japanese Orthopaedic Association; LBP = low-back pain; LL = lumbar lordosis; LSS = lumbar spinal canal stenosis; MEL = microendoscopic laminectomy; PI = pelvic incidence; PT = pelvic tilt; PVM = paravertebral muscle; QOL = quality of life; SS = sacral slope; SVA = sagittal vertical axis; VAS = visual analog scale; fat infiltration; microendoscopic lumbar decompression; paravertebral muscle degeneration; sagittal vertical axis; spinopelvic parameter