title: [Interspinous spacers and disc herniation. Geomorphometric and clinical study of 71 cases treated by L4-L5 microdiscectomy associated to spacer placement].
abstract: OBJECTIVE
  A controversial indication of interspinous spacers is their use as a complement to discectomy. At the present time, there is no solid clinical evidence of effectiveness of that association, which might result from variability in spacer positioning, restricting its correct biomechanical actions. In this study our goal was to identify and analyse the variability in the placement of an interspinous spacer, and to investigate its relationship with the clinical results.
  
  
  METHODS
  We performed a retrospective study on X-ray films from 71 patients suffering from disc herniation in L4-L5 who underwent surgery in our hospital, consisting of: microdiscectomy and biomed interspinous spacer implantation. The geomorphometric techniques used to analyse the data were procrustes superimposition and principal components analysis. We compared the clinical results (using the Herron and Turner scale), segmental lordosis and surgical distraction with the geomorphometric parameters.
  
  
  RESULTS
  Significant morphological variability was found in the implant position showing cephalo-caudal translation and clockwise-counterclockwise rotations. This variability did not correlate with clinical results. A relationship with anatomical features (lordosis) and additional surgical distraction was identified. A different morphology of implant-segment configuration was identified in cases with recurrence of disc herniation.
  
  
  CONCLUSIONS
  Geometric morphometrics allowed identifying high variability in the final placement of interspinous spacers. Nevertheless, it seems not to be related to the clinical outcome, depending rather on the degree of lordosis and distraction. Some differences in segment-implant morphology were identified in cases with recurrences. To assess the effectiveness of spacers, larger studies including morphological and clinical variables are required.
authors.affiliation: Servicio de Neurocirugía, Hospital MAZ, Zaragoza, España; Facultad de Ciencias de la Salud, Universidad San Jorge, Zaragoza, España. Electronic address: jaso@maz.es.
authors.forename: José
authors.initials: J
authors.lastname: Aso Escario
authors.affiliation: Servicio de Traumatología y Cirugía Ortopédica, Hospital Universitario Miguel Servet, Zaragoza, España.
authors.forename: Alberto
authors.initials: A
authors.lastname: Aso Vizán
authors.affiliation: Servicio de Neurocirugía, Hospital MAZ, Zaragoza, España.
authors.forename: José Vicente
authors.initials: JV
authors.lastname: Martínez Quiñones
authors.affiliation: Servicio de Neurocirugía, Hospital MAZ, Zaragoza, España.
authors.forename: Fabian
authors.initials: F
authors.lastname: Consolini
authors.affiliation: Servicio de Neurocirugía, Hospital Carlos Haya, Málaga, España.
authors.forename: Álvaro
authors.initials: Á
authors.lastname: Martín Gallego
authors.affiliation: Servicio de Neurocirugía, Hospital MAZ, Zaragoza, España.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Arregui Calvo
mesh_terms: D003131:Combined Modality Therapy; D017586:Diskectomy / Q000379:methods; D005260:Female; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000601:surgery*; D008159:Lumbar Vertebrae; D008297:Male; D008866:Microsurgery; D008875:Middle Aged; D019736:Prostheses and Implants; D012189:Retrospective Studies
keywords: Análisis de componentes principales; Disc herniation; Discectomy; Discectomía; Espaciador; Hernia discal; Interespinoso; Interspinous; Principal components analysis; Procrustes; Spacer