Diagnosis of Lumbar Spinal Stenosis with Functional Myelography

Abstract

Background and Study Aims The diagnosis of a lumbar spinal stenosis demands advanced diagnostic radiologic techniques. In recent decades magnetic resonance imaging (MRI) has replaced myelography, now considered an old-fashioned technique. It was our hypothesis that functional myelography still plays an important role in selected cases. We investigated how our surgical strategy was influenced by the results of MRI, functional myelography, and postmyelography computed tomography (CT) in patients with a lumbar spinal stenosis.

Methods The sagittal diameters of the lumbar spinal canal were measured from L1 to S1 on patients with lumbar spinal stenosis. MRI, functional myelography, and postmyelography CT were compared in each of the patients. Sensitivity and specificity were calculated in each method. We examined how the surgical strategy was influenced by the results of these different methods.

Results Fifty consecutive patients (21 women and 29 men; mean age: 70 years, [range: 49–86 years]) fulfilled the inclusion criteria. Functional myelography revealed a sensitivity of 0.99, a specificity of 0.79, and a positive predictive value of 0.45. The MRI exhibited a sensitivity of 0.93, a specificity of 0.74, and a positive predictive value of 0.39. Postmyelography CT showed a sensitivity of 0.96, a specificity of 0.75, and a positive predictive value of 0.41. A functional myelography revealed more information than the MRI and resulted in a change in the surgical strategy in 11 of 50 patients (22%) in comparison with the sole results of MRI or a postmyelography CT.

Conclusions In selected cases with multilevel lumbar spinal stenosis, functional myelography revealed the highest precision in reaching a correct diagnosis. It resulted in a change in the surgical approach in every fifth patient in comparison with the MRI and proved most helpful, especially in elderly patients.

Keywords

lumbar spinal stenosis - functional myelography - magnet resonance imaging - postmyelography computer tomography - elderly patients

• References

• 1 Arbit E, Pannullo S. Lumbar stenosis: a clinical review. Clin Orthop Relat Res 2001; (384) 137-143
• 2 Verbiest H. Fallacies of the present—definition, nomenclature, and classification of the stenosis of the lumbar vertebral canal. Spine 1976; 1 (04) 217-225
• 3 Kent DL, Haynor DR, Larson EB, Deyo RA. Diagnosis of lumbar spinal stenosis in adults: a metaanalysis of the accuracy of CT, MR, and myelography. AJR Am J Roentgenol 1992; 158 (05) 1135-1144
• 4 de Graaf I, Prak A, Bierma-Zeinstra S, Thomas S, Peul W, Koes B. Diagnosis of lumbar spinal stenosis: a systematic review of the accuracy of diagnostic tests. Spine 2006; 31 (10) 1168-1176
• 5 Modic MT, Masaryk T, Boumphrey F, Goormastic M, Bell G. Lumbar herniated disk disease and canal stenosis: prospective evaluation by surface coil MR, CT, and myelography. AJR Am J Roentgenol 1986; 147 (04) 757-765
• 6 Forristall RM, Marsh HO, Pay NT. Magnetic resonance imaging and contrast CT of the lumbar spine. Comparison of diagnostic methods and correlation with surgical findings. Spine 1988; 13 (09) 1049-1054
• 7 Bischoff RJ, Rodriguez RP, Gupta K, Righi A, Dalton JE, Whitecloud TS. A comparison of computed tomography-myelography, magnetic resonance imaging, and myelography in the diagnosis of herniated nucleus pulposus and spinal stenosis. J Spinal Disord 1993; 6 (04) 289-295
• 8 Sortland O, Magnaes B, Hauge T. Functional myelography with metrizamide in the diagnosis of lumbar spinal stenosis. Acta Radiol Suppl 1977; 355: 42-54
• 9 Penning L, Wilmink JT. Biomechanics of lumbosacral dural sac. A study of flexion-extension myelography. Spine 1981; 6 (04) 398-408
• 10 Mihale J, Bartko D, Turcáni P, Nováková Z. Specific aspects of mobility and changes in the shape of the dural sac in functional lumbosacral myelography. [in Slovak]. Cesk Neurol Neurochir 1990; 53 (04) 257-263
• 11 Santi Rao D, Rodegerdts U. Functional myelograhy in spondylolisthesis. Arch Orthop Trauma Surg 1983; 101 (02) 75-82
• 12 Fortin JD, Wheeler MT. Imaging in lumbar spinal stenosis. Pain Physician 2004; 7 (01) 133-139
• 13 Deyo RA, Bigos SJ, Maravilla KR. Diagnostic imaging procedures for the lumbar spine. Ann Intern Med 1989; 111 (11) 865-867
• 14 Penning L, Wilmink JT. Posture-dependent bilateral compression of L4 or L5 nerve roots in facet hypertrophy. A dynamic CT-myelographic study. Spine 1987; 12 (05) 488-500
• 15 Kanno H, Ozawa H, Koizumi Y. , et al. Dynamic change of dural sac cross-sectional area in axial loaded magnetic resonance imaging correlates with the severity of clinical symptoms in patients with lumbar spinal canal stenosis. Spine 2012; 37 (03) 207-213
• 16 Morita M, Miyauchi A, Okuda S, Oda T, Iwasaki M. Comparison between MRI and myelography in lumbar spinal canal stenosis for the decision of levels of decompression surgery. J Spinal Disord Tech 2011; 24 (01) 31-36