Variations when measuring slip and lumbar index were studied in three lumbar specimens with different degrees of artificially created L5-S1 spondylolisthesis. Lateral radiographs were obtained with the specimens tilted and/or rotated mimicking an every-day examination situation. Slip and lumbar index were measured; slip was estimated according to a measuring method advocated by Boxall et coll. (3) but slightly modified by us. Six radiologists evaluated each film independently. The magnitude of interobserver and intraobserver errors and variations due to positioning was found to be equally large—about 15 per cent each. Although the total measurement variation was not equal to the sum of errors involved, radiologic evaluation of degree of spondylolisthesis was found to be highly unreliable.
AnderssonG. B. J.SchultzA.NathanA.IrstamL.: Roentgenographic measurement of lumbar intervertebral disc height. Spine6 (1981), 154.
2.
BeggA. C.FalconerM. A.: Plain radiography in intraspinal protrusion of lumbar intervertebral disks. A correlation with operative findings. Brit. J. Surg.36 (1949), 225.
3.
BoxallD.BradfordD. S.WinterR. B.MoeJ. H.: Management of severe spondylolisthesis in children and adolescents. J. Bone Jt Surg. 61-A (1979), 479.
DandyD. J.ShannonM. J.: Lumbosacral subluxation. J. Bone Jt Surg. 53-B (1971), 578.
6.
FredricksonB. E.BakerD.McHolickW. J.YuanH. A.LubickyJ. P.: The natural history of spondylolysis and spondylolisthesis. J. Bone Jt Surg. 66-A (1984), 699.
KeessenW.DuringJ.BeeckerTh. W.GoudfrooijH.CroweA.: Recordings of the movement at the intervertebral segment L5-SI. A technique for the determination of the movement in the L5-SI spinal segment by using three specified postural positions. Spine9 (1984), 83.
9.
LaurentL. E.EinolaS.: Spondylolisthesis in children and adolescents. Acta Orthop. Scand.31 (1961), 45.
10.
LorenzR.BüloW.: Schweregradeinteilung der Spondylolisthesis. Anwendbarkeit und Wert verschiedener Messverfahren. Röntgenblätter35 (1982), 74.
MariqueP.: Le spondylolisthésis. Acta Chir. Belg. (1951) Suppl. No. 3.
14.
MeschanI.: Spondylolisthesis. A commentary on etiology, and an improved method of roentgenographic mensuration and detection of instability. Amer. J. Roentgenol.53 (1945), 230.
NewmanP. H.: A clinical syndrome associated with severe lumbosacral subluxation. J. Bone Jt Surg. 47-B (1965), 472.
17.
OlssonT. H.SelvikG.WillnerS.: Kinematic analysis of posterolateral fusion in the lumbosacral spine. Acta Radiol. Diagnosis17 (1976), 519.
18.
OlssonT. H.SelvikG.WillnerS.Vertebral motion in spondylolisthesis. Acta Radiol. Diagnosis17 (1976), 861.
19.
OlssonT. H.SelvikG.WillnerS.Mobility in the lumbosacral spine after fusion studied with the aid of roentgen stereophotogrammetry. Clin. Orthop.129 (1977), 181.
20.
PearcyM.PortekI.ShepherdJ.: Three-dimensional xray analysis of normal movement in the lumbar spine. Spine9 (1984), 294.
21.
PenningL.BlickmanJ. R.: Instability in lumbar spondylolisthesis. A radiologic study of several concepts. Amer. J. Roentgenol.134 (1980), 293.
