Spondylolysis also known as a pars defect or pars fracture, is a defect or stress fracture in the pars interarticularis of the vertebral arch.Iwamoto, J., Takeda, T., Wakano, K. Returning athletes with severe low back pain and spondylolysis to original sporting activities with conservative treatment. Sports Scandinavian Journal of Medicine and Science in Sports. 2004;14(6):346–351. The vast majority of cases occur in the lower lumbar vertebrae (L5), but spondylolysis may also occur in the cervical vertebrae.Dubousset, J. Treatment of Spondylolysis and Spondylolisthesis in Children and Adolescents. Clinical Orthopaedics and Related Research. 1997;337:77–85.
Signs and symptoms In majority of cases, spondylolysis presents asymptomatically, which can make diagnosis both difficult and incidental. When a patient does present with symptoms, there are general signs and symptoms a clinician will look for:
Clinical signs:Humphreys, D. "Lecture on Spondylolysis and Spondylolisthesis". [OWL]. Western University Kinesiology Program; 2015. Pain on completion of the stork test (placed in hyperextension and rotation) Excessive lordotic posture Unilateral tenderness on palpation Visible on diagnostic imaging (Scottie dog fractureScottie dog fracture) Symptoms: Unilateral low back pain Pain that radiates into the buttocks or legs Onset of pain can be acute or gradual Pain that can restrict daily activities Pain that worsens after strenuous activity Pain aggravated with lumbar hyperextension Difficulty in movement in spinal cord
Cause The cause of spondylolysis sometimes remains unknown, however many factors are thought to contribute to its development. The condition is present in up to 6% of the population, the majority of which usually present asymptomatically.McTimoney, M. & Micheli, L. J. Current Evaluation and Management of Spondylolysis and Spondylolisthesis. Current Sports Medicine Reports. 2003, 2:41–46 Research supports that there are hereditary and acquired risk factors that can make one more susceptible to the defect. The disorder is generally more prevalent in males than in females and tends to occur earlier in males due to their involvement in more strenuous activities at a younger age.Canzonieri, C., & Pilloud, M. A. The Occurrence and Possible and Aetiology of spondylolysis in a Pre-Contact California Population. International Journal of Osteoarchaeology. 2012, 24:602-613 In a young athlete, the spine is still growing; there are many ossification centers, leaving points of weakness in the spine. This leaves young athletes at increased risk, particularly when involved in repetitive hyperextension and rotation across the lumbar spine.McCleary, M. D. and Congeni, J. A. Current concepts in the diagnosis and treatment of spondylolysis in young athletes. Current sports medicine reports. 2007;6(1):62-66. Spondylolysis is a common cause of low back pain in preadolescents and adolescent athletes, as it accounts for about 50% of all low back pain. It is believed that both repetitive trauma and an inherent genetic weakness can make an individual more susceptible to spondylolysis.Spondylolysis and Spondylolisthesis of the Lumbar Spine. Children's Orthopaedics, Mass General. Available at: http://www.massgeneral.org/ortho-childrens/conditions-treatments/spondylolysis.aspx . Accessed March 28, 2016
Risk factors Sports involving repetitive or forceful hyperextension of the spine, especially when combined with rotation are the main mechanism of injury for spondylolysis. The stress fracture of the pars interarticularis occurs on the side opposite to activity. For instance, for a right-handed player, the fracture occurs on the left side of the vertebrae. Spondylolysis has a higher occurrence in the following activities: Baseball Military service Tennis Diving Ballet Cheerleading Gymnastics Gridiron Football Association Football Wrestling Weightlifting Roller Derby Cricket Pole Vault Rugby Volleyball Gym Ultimate Frisbee (especially during impact from laying out) Muay Thai Hockey (due to the bending of the waist) Although this condition can be caused by repetitive trauma to the lumbar spine in strenuous sports, other risk factors can also predispose individuals to spondylolysis. Males are more commonly affected by spondylolysis than females. In one study looking at youth athletes, it was found that the mean age of individuals with spondylolysis was 20 years of age.Debnath, U. K., Freeman, B. J. C., Gregory, P., de la Harpe, D., Kerslake, R. W. and Webb, J.K. Clinical outcome and return to sport after the surgical treatment of spondylolysis in young athletes. Journal of Bone and Joint Surgery, British Volume. 2003, 85(2): 244-249. Spondylolysis also runs in families suggesting a hereditary component such as a predisposition to weaker vertebrae.
Pathophysiology Spondylolysis is a bony defect or fracture within the pars interarticularis of the vertebral arch in the spinal column. The vast majority of spondylolysis occur in the lumbar vertebrae, however it can also be seen in cervical vertebrae. The lumbar vertebra consist of a body, pedicle, lamina, pars interarticularis, transverse process, spinous process and superior and inferior articular facets, which form joints that link the vertebrae together. When examining the vertebra, the pars interarticularis is the bony segment between the superior and inferior articular facet joints located anterior to the lamina and posterior to the pedicle. Separation of the pars interarticularis occurs when spondylolysis is present in the spinal column.Standaert, C.J., Herring, S.A., Cole, A.J., Stratton, S.A. The Lumbar Spine and Sports. Low Back Pain Handbook. 2003:385–404.
Spondylolysis is typically caused by a stress fracture of the bone, and is especially common in adolescents who over-train in activities. The pars interarticularis is vulnerable to fracture during spinal hyperextension, especially when combined with rotation, or when experiencing a force during a landing. This stress fracture most commonly occurs where the concave lumbar spine transitions to the convex sacrum (L5-S1). A significant number of individuals with spondylolysis will develop spondylolisthesis, which is true for 50-81% of this population.Cianfoni A, Cerase A, Magarelli N, Bonomo L. Lumbar spondylolysis: a review. Skeletal Radiology. 2011;40:683-700.Syrmou, E., Tsitsopoulos, P. P., Marinopoulos, D., Tsonidis, C., Anagnostopoulos, I., & Tsitsopoulos, P. D.Spondylolysis: A Review and Reappraisal. H Quarterly Medical Journal. 2010;14(1): 17–21
Diagnosis There are several imaging techniques used to diagnose spondylolysis. Common imaging techniques include X-ray, MRI, Bone Scintigraphy (Bone Scan), and Computed Tomography (CT Scan).
The scottie dog sign It was once used as a diagnostic sign in x-rays, for lumbar spondylolysis, but it is not commonly in use nowadays because of the advent of more sensitive diagnostic methods such as the CT scan and MRI scan. If spondylolysis is present, the pars interarticularis, or the neck of the dog, gives the appearance of a Scottish Terrier with a collar around its neck. X-Ray X-rays (electromagnetic radiation) are projected through the body to produce an image of its internal structures. The radiation is more attenuated (absorbed) by the denser tissues of the body (i.e. bone) than the softer tissues (i.e. muscles, organs, etc.) creating a picture composed of shades of grey ranging from white to black. A vertebra with a fracture or defect of the pars interarticularis will have a dark mark through this region of bone. Since this is difficult to see on the AP (anterior posterior) x-ray view an oblique x-ray of the lumbar spine can usually identify the spondylolysis. If inconclusive a further CT scan can produce a 3-dimensional images to more clearly show the defect although the exam increases the patients radiation dose by at least an order of magnitude than plain x-rays.Masci L, Pike J, Malara F, Phillips B, Bennell K, Brukner P. Use of the one-legged hyperextension test and magnetic resonance imaging in the diagnosis of active spondylolysis.British Journal of Sports Medicine. 2006;40:940-946.X-ray: MedlinePlus Medical Encyclopedia. US National Library of Medicine. 2014. Available at: https://medlineplus.gov/ency/article/003337.htm . Accessed March 30, 2016.
Bone scintigraphy
Also known as a bone scan, bone scintigraphy involves the injection of a small amount of radioactive tracer into the bloodstream. This tracer decays and emits radioactive energy which can be detected by a special camera. The camera produces a black and white image where areas shown as dark black indicate bone damage of some kind. If there is a black spot in the lumbar vertebrae (e.g. L5) this indicates damage and potentially spondylolysis. If this test is positive, a CT scan is usually ordered to confirm spondylolysis.
Computed tomography
Commonly known as a CT Scan or CAT scan, this form of imaging uses x-rays to produce multiple cross-sectional images, or "slices", through a part of the body. This allows a physician to evaluate the body in greater detail than an x-ray allows. For this reason the CT scan is much more accurate in detecting spondylolysis than an x-ray. Bone scintigraphy combined with CT scan is considered the reference standard, which means that it is best at detecting spondylolysis.Body CT (CAT Scan). Body CT (CAT Scan). 2016. Available at: http://www.radiologyinfo.org/en/info.cfm?pg=bodyct . Accessed March 30, 2016.
MRI MRI is a newer technique used to diagnose spondylolysis and is favorable for a few reasons. MRI is more accurate than x-ray and does not use radiation. Instead, MRI uses powerful magnets and radio frequency pulses to produce cross-sectional images.Body MRI - magnetic resonance imaging of the chest, abdomen and pelvis. Body MRI - magnetic resonance imaging of the chest, abdomen and pelvis. 2014. Available at: http://www.radiologyinfo.org/en/info.cfm?pg=bodymr . Accessed March 30, 2016.
Treatment Treatment for spondylolysis ranges from bracing, activity restriction, extension exercises, flexion exercises and deep abdominal strengthening, that is administered through physical therapy. The duration of physical therapy a patient receives varies upon the severity of spondylolysis, however typically ranges from three to six months. The goal of physical therapy is to minimize movement at the unstable defect of the pars interarticularis. Once a patient completes physical therapy, and displays no symptoms or inflammation in the lower back, they are cleared to continue with daily or athletic activities. However, a patient may need to maintain a variety of rehabilitation techniques after physical therapy to prevent the recurrence of spondylolysis.Pizzutillo, PD, Hummer, CD. Nonoperative Treatment for Painful Adolescent Spondylolysis or Spondylolisthesis. Journal of Pediatric Orthopaedics. 1989;9(5):538–540.
Exercise The aim of deep abdominal co-contraction exercises is to train muscles surrounding the lumbar spine which provide stability of the spine. Spondylolysis results in a spinal instability and disrupts patterns of co-recruitment between muscle synergies. Specifically, local muscles that attach directly to the spine are affected. The lumbar multifidus and transversus abdominis play a direct role in stabilizing the lumbar spine. Instead the local muscles in individuals with spondylolysis are vulnerable to dysfunction, which results in abnormal spinal stability causing chronic low back pain. To compensate, the large torque producing global muscles are used to stabilize the spine.O'Sullivan, P. B., Phyty, D. M., Twomey, L. T., & Allison, G. T.Evaluation of Specific Stabilizing Exercise in the Treatment of Chronic Low Back Pain with Radiologic Diagnosis of Spondylolysis or Spondylolisthesis. Spine. 1997, 22(24):2959-2967.