Spondylolysis Imaging 

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Spondylolysis is a common clinical condition that can result in low back pain. Patients with spondylolysis have a defect in the pars interarticularis of the neural arch, that portion of the neural arch that connects the superior and inferior articular facets. On oblique radiographs, the posterior elements form the appearance of a Scottie dog. A break in the pars interarticularis can have the appearance of a collar around the neck (see the images below). Spondylolysis is believed to be caused by repeated microtrauma, resulting in stress fracture of the pars interarticularis. Heredity also is believed to be a factor. Patients with spina bifida occulta have an increased risk for spondylolysis. Approximately 95% of cases of spondylolysis occur at the L5 level. Lyses can occur much less commonly at other lumbar or the thoracic levels. Involvement of multiple levels is rare. The process may be unilateral or bilateral. Patients with bilateral pars defects can progress to spondylolisthesis. The degree of slippage of adjacent vertebral bodies varies and can progress over time. ^{[1, 2, 3, 4, 5, 6]}

Patients with suspected spondylolysis should be evaluated initially with plain radiography, consisting of anteroposterior, lateral, and oblique views of the lumbar spine. The lateral views are most sensitive for detection of pars fractures, and the oblique views are most specific. Radiography of the lumbar spine is limited by its inability to detect stress reactions in the pars interarticularis that have not progressed to complete fracture.  Early spondolytic defects may be seen in approximately 30–38% of the cases. If plain radiographs are negative or inconclusive, further imaging may be warranted. Magnetic resonance imaging (MRI), computed tomography (CT) scanning, and single-photon emission computed tomography (SPECT) bone scintigraphy are used to further evaluate patients with suspected spondylolysis. ^{[7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26]}

Some investigators and practicing radiologists believe that after normal radiographs have been obtained, MRI of the lumbar spine should be next. However, the MRI examination must be performed with thin-section images (3 mm) and at relatively high resolution (256 x 192 matrix). Imaging should be obtained in 2 planes: sagittal and axial. Obtain T1-weighted (short recovery time [TR]/echo time [TE]) and T2-weighted (long TR/TE) with fat-suppression images. Usually, this type of MRI examination requires a high-field magnet (minimum of 1 T). ^{[13, 27, 28, 19]}

CT scanning of the lumbar spine can be performed after obtaining radiographs or after an equivocal MRI. Perform the examination with stacked thin (2 mm) axial sections through the portion of the spine in question. Perform sagittal reconstructions. However, even without reconstructions, pars fractures can be identified on CT because of the absence of a complete ring of bony structures at a given vertebral level. ^{[7, 10, 19, 20]}

CT of the lumbar spine is not sensitive for detecting early acute stress reactions in the pars interarticularis where there is only marrow edema and microtrabecular fracture. ^{[13, 29]}  These findings, although not visible on CT, are observed easily on MRI; thus, MRI of the lumbar spine can easily identify acute stress reactions in the pars interarticularis. However, direct identification of pars defects may be slightly more difficult with MRI than with CT. The presence of facet osteophytes, combined with volume averaging, occasionally can obscure the presence of the pars defect in the sagittal plane. ^[30]

SPECT bone scintigraphy also can be obtained after plain radiographs and easily identifies acute stress reaction in the pars interarticularis; however, anatomic details such as the pars defect cannot be identified directly with bone scan. This means that old lyses usually are not seen. ^[31]  SPECT can provide images in the axial, coronal, and sagittal planes. SPECT is superior to planar bone scan and plain radiographs but limited by high rates of false-positive and false-negative results and by high radiation dose. ^{[21, 22]} The spatial resolution of SPECT bone scintigraphy is less than that of CT scanning or MRI. ^[23]

A lateral radiograph of spondylolysis and a defect in the pars interarticularis are presented in the images below.

On lateral radiographs, the most sensitive projection, spondylolysis appears as a linear lucency in the pars interarticularis (see the images below). This lucency also can be seen on oblique radiographs, the most specific projection. If spondylolysis is bilateral, the defect should be visible on the right and left obliques. At times, however, the fracture is obscured. The lucency seen in the pars interarticularis on oblique radiographs has been termed the collar on the neck of the Scottie dog. ^{[32, 33, 29, 30]}

Secondary radiographic signs exist that are occasionally seen in association with spondylolysis. These include sclerosis of the contralateral pedicle and the presence of spina bifida occulta at the level of the lysis. ^[32]

When a pars defect is identified on lumbar spine radiographs, further imaging usually is not needed. False-positive diagnoses of spondylolysis on radiographs of the lumbar spine are uncommon. One possible cause of a false-positive result is bowel gas superimposed over the region of the pars interarticularis that simulates the lucency of the pars defect. ^[32]  False-negative diagnoses of spondylolysis occur when the lucent defect in the pars interarticularis is not seen or when there is a radiographically occult stress reaction without lysis. Nonvisualization of the pars defect occurs if the plane of the defect lies near the sagittal plane. ^[32]

Spondylolysis on CT of the lumbar spine is seen as a linear lucency or defect extending through the pars interarticularis. In some patients, fragmentation of the pars interarticularis may be seen. These findings are identified most easily on sagittal reconstructions of the axial images (an example of which appears below). On axial images, a pars defect can be identified easily by virtue of the absence of a complete bony ring at any given vertebral level. ^{[10, 16, 19, 24]}

Bone absorption is seen in the early stage, and usually it is demonstrated as an incomplete fracture. In later stages, spondylolysis progresses to complete fracture and pseudoarthrosis. ^[34]  When spondylolysis is seen on CT scans of the lumbar spine, further imaging is not needed. Decreased-dose CT is the optimal examination to confirm a high suspicion of spondylolysis in children and adolescents, with dose essentially equivalent to radiographs. In a study of 42 pediatric patients at a single institution, decreased-dose CT provided a greater level of agreement than 2D MRI and 2D + 3D MRI. ^[25]  False-negative results can occur on CT scans of the lumbar spine when an acute stress reaction in the pars interarticularis is seen that has not progressed to fracture or fragment.>

In a study of 717 CT scans in 532 children, 25 cases of spondylolysis were identified in 14 of 273 boys and 11 of 259 girls, with 12 being associated with grade 1 spondylolisthesis. Prevalence was 1% in children younger than 3 years; 3.7% in children younger than 6 years; and 4.7% for all 532 patients. ^[26]

Spondylolysis on MRI of the lumbar spine has a variable appearance that depends on the timing of the examination. Patients with an acute stress reaction have increased signal on long TR (T2-weighted) images in the pars interarticularis. This represents marrow edema. On short TR (T1-weighted) images, decreased signal is seen in the pars interarticularis. (See the images below.) ^{[13, 17, 18, 27, 28, 35, 36, 37]}

Patients with an actual fracture of the pars interarticularis have a discontinuity or fragmentation of the pars interarticularis that is seen best on sagittal short TR images. On long TR images, signal may be decreased in the pars if the process is chronic, indicating reactive sclerosis. If a pars defect is found with increased signal on long TR images, this indicates a subacute process. ^{[27, 28]}  When spondylolysis is seen on MRI, no further imaging is required. This applies to stress reaction in the pars, as well as to fractures. ^{[27, 28]}  A false-positive MRI of the lumbar spine rarely occurs when active facet joint arthropathy with reactive marrow edema is seen in the pars interarticularis. ^{[27, 28]} Typically, this should have a different appearance than an acute stress reaction in the pars. With arthropathy, edema extends beyond the pars and, possibly, at more than 1 level. A false-negative MRI of the lumbar spine may occur in the setting of facet joint arthropathy with facet osteophytes that obscure the pars defect.

In a study by Yamaguchi et al, spondylolysis was missed by MRI in over half of adolescents in one consecutive series (7 of 11 patients). As a result, the authors suggested that in patients with a history or physical findings suggestive of spondylolysis, such as localized pain of the lumbar spine with back extension, further radiographic evaluation should be considered if an MRI is negative. ^[38]

Spondylolysis is seen on methylene diphosphonate technetium-99m (^99mTc) bone scan with SPECT as increased activity in the pars interarticularis (as seen in the images below). This finding typically represents an acute stress reaction that radiographs of the lumbar spine will not reveal as a defect in the pars. ^{[29, 15]}

If increased activity is seen in the pars interarticularis, additional imaging may be needed. Correlation with lumbar spine radiographs is recommended. If radiographs are negative for spondylolysis, consider further imaging with either MRI or CT. Other causes of increased activity may exist in the region of the pars that are not related to spondylolysis. False-positive diagnoses of spondylolysis include infection and osteoid osteoma. These can cause increased activity in the region of the pars similar to that seen with spondylolysis. False-negative diagnoses can occur in the setting of chronic spondylolysis. In this situation, normal activity usually is seen in the region of the pars interarticularis. In addition, old defects of the pars interarticularis may not show increased activity.

Healing stress reactions also may show increased activity in the pars interarticularis. On planar imaging, increased activity in the pars interarticularis may be mistaken for osteoarthritis in the facet joints.

Blanda J, Bethem D, Moats W, Lew M. Defects of pars interarticularis in athletes: a protocol for nonoperative treatment. J Spinal Disord. 1993 Oct. 6(5):406-11. [Medline].

Kurd MF, Patel D, Norton R, Picetti G, Friel B, Vaccaro AR. Nonoperative Treatment of Symptomatic Spondylolysis. J Spinal Disord Tech. 2007 Dec. 20(8):560-564. [Medline].

Yamamoto T, Iinuma N, Miyamoto K, Sugiyama S, Nozawa S, Hosoe H. Segmental wire fixation for lumbar spondylolysis associated with spina bifida occulta. Arch Orthop Trauma Surg. 2007 Nov 27. [Medline].

Gregg CD, Dean S, Schneiders AG. Variables associated with active spondylolysis. Phys Ther Sport. 2009 Nov. 10(4):121-4. [Medline].

Donnally III CJ, Dulebohn SC. Lumbar Spondylolysis And Spondylolisthesis. 2018 Jan. [Medline]. [Full Text].

Lawrence KJ, Elser T, Stromberg R. Lumbar spondylolysis in the adolescent athlete. Phys Ther Sport. 2016 Jul. 20:56-60. [Medline].

Miller R, Beck NA, Sampson NR, Zhu X, Flynn JM, Drummond D. Imaging modalities for low back pain in children: a review of spondyloysis and undiagnosed mechanical back pain. J Pediatr Orthop. 2013 Apr-May. 33(3):282-8. [Medline].

Wasser JG, Zaremski JL, Herman DC, Vincent HK. Assessment and rehabilitation of chronic low back pain in baseball: part II. Res Sports Med. 2017 Apr-Jun. 25 (2):231-243. [Medline]. [Full Text].

Mofidi A, Tansey C, Mahapatra SR, Mirza HA, Eisenstein SM. Cervical spondylolysis, radiologic pointers of stability and acute traumatic as opposed to chronic spondylolysis. J Spinal Disord Tech. 2007 Aug. 20(6):473-9. [Medline].

Krupski W, Majcher P, Tatara MR. Computed tomorgaphy diagnostic of lumbar spondylolysis. Ortop Traumatol Rehabil. 2004 Oct 30. 6(5):652-7. [Medline].

Krupski W, Majcher P. Radiological diagnostic of lumbar spondylolysis. Ortop Traumatol Rehabil. 2004 Dec 30. 6(6):809-18. [Medline].

Masharawi Y, Dar G, Peleg S, Steinberg N, Alperovitch-Najenson D, Salame K. Lumbar facet anatomy changes in spondylolysis: a comparative skeletal study. Eur Spine J. 2007 Jul. 16(7):993-9. [Medline].

Sairyo K, Katoh S, Takata Y, Terai T, Yasui N, Goel VK. MRI signal changes of the pedicle as an indicator for early diagnosis of spondylolysis in children and adolescents: a clinical and biomechanical study. Spine. 2006 Jan 15. 31(2):206-11. [Medline].

Gregory PL, Batt ME, Kerslake RW, Webb JK. Single photon emission computerized tomography and reverse gantry computerized tomography findings in patients with back pain investigated for spondylolysis. Clin J Sport Med. 2005 Mar. 15(2):79-86. [Medline].

Trout AT, Sharp SE, Anton CG, Gelfand MJ, Mehlman CT. Spondylolysis and Beyond: Value of SPECT/CT in Evaluation of Low Back Pain in Children and Young Adults. Radiographics. 2015 May-Jun. 35 (3):819-34. [Medline].

Fadell MF, Gralla J, Bercha I, Stewart JR, Harned RK, Ingram JD, et al. CT outperforms radiographs at a comparable radiation dose in the assessment for spondylolysis. Pediatr Radiol. 2015 Jul. 45 (7):1026-30. [Medline].

Rush JK, Astur N, Scott S, Kelly DM, Sawyer JR, Warner WC Jr. Use of magnetic resonance imaging in the evaluation of spondylolysis. J Pediatr Orthop. 2015 Apr-May. 35 (3):271-5. [Medline].

Goda Y, Sakai T, Sakamaki T, Takata Y, Higashino K, Sairyo K. Analysis of MRI signal changes in the adjacent pedicle of adolescent patients with fresh lumbar spondylolysis. Eur Spine J. 2014 Sep. 23 (9):1892-5. [Medline].

Belfi LM, Ortiz AO, Katz DS. Computed tomography evaluation of spondylolysis and spondylolisthesis in asymptomatic patients. Spine. 2006 Nov 15. 31(24):E907-10. [Medline].

Yuksel M, Yuksel KZ, Demirpolat G. Evaluation of degenerative diseases of the lumbar spine with reformatted and 3-dimensional computed tomography images. Saudi Med J. 2012 Jul. 33(7):776-81. [Medline].

Tofte JN, CarlLee TL, Holte AJ, Sitton SE, Weinstein SL. Imaging Pediatric Spondylolysis: A Systematic Review. Spine (Phila Pa 1976). 2017 May 15. 42 (10):777-782. [Medline].

Ledonio CG, Burton DC, Crawford CH 3rd, Bess RS, Buchowski JM, Hu SS, et al. Current Evidence Regarding Diagnostic Imaging Methods for Pediatric Lumbar Spondylolysis: A Report From the Scoliosis Research Society Evidence-Based Medicine Committee. Spine Deform. 2017 Mar. 5 (2):97-101. [Medline].

Kobayashi A, Kobayashi T, Kato K, Higuchi H, Takagishi K. Diagnosis of radiographically occult lumbar spondylolysis in young athletes by magnetic resonance imaging. Am J Sports Med. 2013 Jan. 41(1):169-76. [Medline].

Brooks BK, Southam SL, Mlady GW, Logan J, Rosett M. Lumbar spine spondylolysis in the adult population: using computed tomography to evaluate the possibility of adult onset lumbar spondylosis as a cause of back pain. Skeletal Radiol. 2009 Nov 13. [Medline].

Delavan JA, Stence NV, Mirsky DM, Gralla J, Fadell MF. Confidence in Assessment of Lumbar Spondylolysis Using Three-Dimensional Volumetric T2-Weighted MRI Compared With Limited Field of View, Decreased-Dose CT. Sports Health. 2016 Jul. 8 (4):364-71. [Medline]. [Full Text].

Lemoine T, Fournier J, Odent T, Sembély-Taveau C, Merenda P, Sirinelli D, et al. The prevalence of lumbar spondylolysis in young children: a retrospective analysis using CT. Eur Spine J. 2017 Oct 13. [Medline].

Ulmer JL, Mathews VP, Elster AD, et al. MR imaging of lumbar spondylolysis: the importance of ancillary observations. AJR Am J Roentgenol. 1997 Jul. 169(1):233-9. [Medline].

Ulmer JL, Elster AD, Mathews VP, Allen AM. Lumbar spondylolysis: reactive marrow changes seen in adjacent pedicles on MR images. AJR Am J Roentgenol. 1995 Feb. 164(2):429-33. [Medline].

Hession PR, Butt WP. Imaging of spondylolysis and spondylolisthesis. Eur Radiol. 1996. 6(3):284-90. [Medline].

Lee J, Ehara S, Tamakawa Y, Shimamura T. Spondylolysis of the upper lumbar spine. Radiological features. Clin Imaging. 1999 Nov-Dec. 23(6):389-93. [Medline].

Saraste H, Nilsson B, Brostrom LA, Aparisi T. Relationship between radiological and clinical variables in spondylolysis. Int Orthop. 1984. 8(3):163-74. [Medline].

Harvey CJ, Richenberg JL, Saifuddin A, Wolman RL. The radiological investigation of lumbar spondylolysis. Clin Radiol. 1998 Oct. 53(10):723-8. [Medline].

Helms CA. Fundamentals of Skeletal Radiology. 2nd ed. WB Saunders Co. 1994.

Sairyo K, Nagamachi A. State-of-the-art management of low back pain in athletes: Instructional lecture. J Orthop Sci. 2016 May. 21 (3):263-72. [Medline]. [Full Text].

Ben-Galim P, Reitman CA. The distended facet sign: an indicator of position-dependent spinal stenosis and degenerative spondylolisthesis. Spine J. 2007 Mar-Apr. 7(2):245-8. [Medline].

Park JS, Moon SK, Jin W, Ryu KN. Unilateral lumbar spondylolysis on radiography and MRI: emphasis on morphologic differences according to involved segment. AJR Am J Roentgenol. 2010 Jan. 194(1):207-15. [Medline].

Wilms G, Maldague B, Parizel P, Meylaerts L, Vanneste D, Peluso J. Hypoplasia of L5 and wedging and pseudospondylolisthesis in patients with spondylolysis: study with MR imaging. AJNR Am J Neuroradiol. 2009 Apr. 30(4):674-80. [Medline].

Yamaguchi KT Jr, Skaggs DL, Acevedo DC, Myung KS, Choi P, Andras L. Spondylolysis is frequently missed by MRI in adolescents with back pain. J Child Orthop. 2012 Jul. 6 (3):237-40. [Medline].

Amato M, Totty WG, Gilula LA. Spondylolysis of the lumbar spine: demonstration of defects and laminal fragmentation. Radiology. 1984 Dec. 153(3):627-9. [Medline].

Porter RW, Park W. Unilateral spondylolysis. J Bone Joint Surg Br. 1982. 64(3):344-8. [Medline].

Fredrickson BE, Baker D, McHolick WJ, et al. The natural history of spondylolysis and spondylolisthesis. J Bone Joint Surg Am. 1984 Jun. 66(5):699-707. [Medline].

Eric P Weinberg, MD Associate Professor, Department of Radiology, University of Rochester Medical Center, Strong Memorial Hospital

Eric P Weinberg, MD is a member of the following medical societies: American College of Radiology, American Roentgen Ray Society, Radiological Society of North America

Disclosure: Nothing to disclose.

Bernard D Coombs, MB, ChB, PhD Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand

Disclosure: Nothing to disclose.

William R Reinus, MD, MBA, FACR Professor of Radiology, Temple University School of Medicine; Chief of Musculoskeletal and Trauma Radiology, Vice Chair, Department of Radiology, Temple University Hospital

William R Reinus, MD, MBA, FACR is a member of the following medical societies: Alpha Omega Alpha, Sigma Xi, American College of Radiology, American Roentgen Ray Society, Radiological Society of North America

Disclosure: Nothing to disclose.

Felix S Chew, MD, MBA, MEd Professor, Department of Radiology, Vice Chairman for Academic Innovation, Section Head of Musculoskeletal Radiology, University of Washington School of Medicine

Felix S Chew, MD, MBA, MEd is a member of the following medical societies: American Roentgen Ray Society, Association of University Radiologists, Radiological Society of North America

Disclosure: Nothing to disclose.

Spondylolysis Imaging 

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