- Email: [email protected]
The Diagnosis and Management of Lumbar Spondylolysis
The Diagnosis and Management of Lumbar Spondylolysis Christopher J. Standaert, MD Spondylolysis is a common cause of low back pain in adolescent athletes. Despite the frequency with which it occurs, there are no controlled trials on treatment and only limited comparative studies between the different imaging modalities available. Given this, there are substantial disagreements among authors as to the optimal means of diagnosing and treating this condition. Based on the current medical literature, however, nuclear imaging with bone scan and single-photon emission computed tomography would appear to represent the best diagnostic screening tool, although additional studies, particularly computed tomography, may be necessary to accurately diagnose and treat an affected athlete. An essential component of treatment is relative rest. Issues related to the diagnosis and management of adolescent athletes with spondylolysis will be addressed, and defined strategies for diagnosis and treatment are presented. Oper Tech Sports Med 13:101-107 © 2005 Elsevier Inc. All rights reserved. KEYWORDS low back pain, lumbar spondylolysis, diagnosis, management, adolescent athletes
S
pondylolysis is defined as a defect in the pars interarticularis of the neural arch and represents a particular clinical problem in adolescent athletes. Although there is a great deal of general agreement that spondylolysis represents a fatigue fracture of the neural arch occurring as a result of repetitive force exposure,1 there is substantial disagreement among authors on the optimal approaches to radiographic assessment and treatment of this disorder, in large part related to the lack of any real controlled trials on the diagnosis or management of adolescent athletes with symptomatic pars lesions. Given this, it is important to understand the literature that is available to develop appropriate diagnostic and treatment strategies for these patients. This article will address these issues and present a framework for a rational approach to the diagnosis and management of adolescent athletes with spondylolysis.
Epidemiology Lesions of the pars are frequent findings on plain radiographs in the general population and are much more commonly seen
Puget Sound Sports and Spine Physicians, Seattle, WA. Department of Rehabilitation Medicine, University of Washington, Seattle, WA. Address reprint requests to Christopher J. Standaert, MD, Puget Sound Sports and Spine Physicians, 1600 E. Jefferson, Suite 401, Seattle, WA 98122. E-mail: [email protected]
1060-1872/05/$-see front matter © 2005 Elsevier Inc. All rights reserved. doi:10.1053/j.otsm.2005.08.004
in populations of adolescent athletes. Fredrickson and coworkers2 prospectively studied 500 first-grade students with plain radiographs and found an overall incidence of spondylolysis of 4.4% at age 6. All of these lesions occurred without any symptoms. This number increased to 5.2% by age 12 and 6% by adulthood. Roche and Rowe3 studied 4,200 cadaveric spines and found an overall incidence of 4.2%. This number varied within subgroups of the population, however, with rates of 6.4% for white males, 2.8% for black males, 2.3% for white females, and 1.1% for black females. There was no significant change in these rates with increasing age from 20 to 80 years old. The vast majority of spondylolytic defects occur at L5 (85%-95%), with L4 being the next most commonly affected level (5%-15%). More proximal lumbar levels are affected much less frequently.2-7 The incidence of spondylolysis seems to be higher in the young athletic population than in the general population. Jackson and coworkers8 studied 100 young female gymnasts with plain radiographs and found spondylolysis in 11%. In a review of 3,152 elite Spanish athletes, Soler and Calderon6 found an overall rate of spondylolysis of 8.02% for the group as a whole based on plain radiographs. They noted higher rates of spondylolysis in gymnasts, weight lifters, throwing track and field athletes, and rowers. Rossi and Dragoni9 have published the results of a study of 4,243 young athletes assessed with plain radiographs. All the athletes had complaints of low back pain and were evaluated between 1962 and 1998 with studies that included anteroposterior, lateral, 101
102 and oblique films. The authors found that 13.9% of the athletes had evidence of spondylolysis on plain radiographs and that 47.5% of these had a concurrent spondylolisthesis. Again, some sports had much higher rates of spondylolysis identified than others, including diving, wrestling, weight lifting, track and field, and gymnastics. In a study by Micheli and Wood,10 spondylolysis was clearly the most frequent diagnosis made in adolescent athletes presenting to a sports medicine clinic with low back pain and was seen far more frequently in these athletes than in a comparative group of adults with low back pain.
Diagnostic Imaging Multiple imaging modalities are available for use in the diagnosis of a patient with a suspected pars lesion, notably plain radiography, nuclear imaging, computed tomography scan (CT), and magnetic resonance imaging (MRI). There is limited available data comparing these studies directly in the diagnosis of spondylolysis; thus, it is difficult to identify the true relative sensitivity and specificity of these tests. The degree and quality of literature on each of these modalities in the setting of spondylolysis is variable as well, with MRI having the least available data when compared with the other types of imaging studies. Given the frequency with which pars defects are identified radiographically in asymptomatic individuals, the goal of diagnostic imaging is not just to identify a pars lesion but also to find indications that that the lesion is likely to be symptomatic. Generally speaking, multiple imaging modalities are usually required to establish an accurate diagnosis. Plain radiography has been an important diagnostic tool for spondylolysis for some time. The defect in isthmic spondylolysis is visualized as a lucency in the region of the pars interarticularis. The lesion is commonly described as having the appearance of a collar or a broken neck on the “Scotty dog” seen in lateral oblique radiographs. Visualizing a defect in the pars on plain radiographs can be difficult, however, and frequently requires multiple views of the lumbosacral spine. In a study by Amato and coworkers,4 the single most sensitive view was the lateral spot view of the lumbosacral junction, which revealed the lesion in 84% of their cases. When just using anterior/posterior, lateral, and lateral oblique views, roughly 19% of the pars defects identified were seen only on the lateral oblique views. Although widely used and studied, plain radiography has been shown to be relatively insensitive compared with newer imaging modalities. In the last 20 years, multiple studies using radionuclide imaging have shown that bone scan and, particularly, single-photon emission computed tomography (SPECT) offer many advantages over isolated plain radiographs in the diagnosis of spondylolysis. Several studies have shown that SPECT is significantly more sensitive than both plain films and planar bone scan11-16 A study by Anderson and coworkers,11 for example, found that, when compared with SPECT, plain radiography failed to demonstrate the pars lesion in 53% of their patients and planar bone scan in 19%. In addition to simply being more sensitive in the identifica-
C.J. Standaert tion of pars lesions than plain radiography, there is also evidence that bone scan or SPECT may be helpful with the crucial task of identifying symptomatic lesions. Studies by Elliot and coworkers14 and Lowe and coworkers17 both suggested that a positive bone scan correlates with a symptomatic lesion. Collier and coworkers,18 Lusins and coworkers,19 and Raby and Mathews,20 all using different lines of research, similarly concluded that a positive SPECT scan correlated strongly with a symptomatic lesion. A significant limitation of nuclear imaging is that, although seemingly quite sensitive in the identification of pars lesions, the specificity of this type of imaging is more suspect. Potential abnormalities that may result in an abnormal SPECT that would otherwise be consistent with spondylolysis include facet arthropathy or fracture, infection, and osteoid osteoma. Additional imaging, particularly with a CT scan, is generally required to clarify the bony abnormality in a patient with a positive SPECT study. Like radionuclide imaging, CT scan has been shown to be more sensitive than plain radiography in revealing pars lesions.21-24 Some authors have used CT as their “gold standard,”7,21 although direct comparisons to SPECT are few and there are little to no data on the correlation between the findings on CT scan and symptoms or clinical outcome, as there has been for nuclear imaging. There is also debate as to the optimal means of data acquisition with CT scan, particularly regarding slice thickness and the angle of the gantry. Some recent studies have used CT scan to “stage” pars defects (Fig. 1) and have noted clear correlations between the radiographic stage of the lesion and the chance of obtaining a bony union with conservative management.7,25,26 The role of MRI in the diagnosis of pars lesions has been controversial. Its efficacy in visualizing the pars had proven somewhat problematic in early studies, but more recent work with improved technical approaches has proven more useful22,27,28 (Fig. 2). MRI clearly offers advantages over SPECT and CT scan in terms of revealing other types of pathology present in the lumbar spine, and the lack of ionizing radiation with MRI may also contribute to this being a particularly desirable modality in studying pars lesions, especially in the female adolescent population.22 Yamane and coworkers29 compared MRI with CT scan and found that MRI may be helpful in identifying lesions in the pars before they are noted on CT and, thus, may have the potential for identifying stress lesions early in their clinical course. There was no comparison to SPECT included in this study, however, nor any data on clinical correlation to the findings on MRI. Hollenberg and coworkers30 recently presented a classification system for findings in the pars interarticularis based on the appearance of the pars on MRI graded on a 0 to 4 scale with defined criteria for each grade thought to correspond with varying types of injuries or pathological states of the pars. Although the authors believed that their classification system was reliable, the clinical utility of this system is unclear. Unfortunately, there was no comparison of these studies to either SPECT or CT scan, no clinical data on outcome, no clear means of establishing pathological correlates to the findings, and no discussion of the prevalence of these findings in a
Lumbar spondylolysis
103
Figure 1 (A) CT scan showing an early-stage pars lesion (arrow) associated with sclerosis and an incomplete fracture line but no significant separation, cortication, or cystic change. (B) CT scan showing a progressive stage pars lesion (arrow) associated with sclerosis, fracture with minimal separation, and cyst formation. There is no cortication of the fracture margins. (C) CT scan showing a terminal stage pars lesion (arrow) with separation and clearly defined, corticated margins.
normal control group. Takata and colleagues31 recently presented an as-yet-unpublished study suggesting that the presence of high-intensity signal in the pedicle on MRI is a predictor of bony healing. Although promising, the role of MRI in the diagnosis and treatment of spondylolysis is not yet clarified in the available literature.
Treatment Studies on the efficacy of various treatment approaches for adolescent athletes with symptomatic spondylolysis are similarly muddied by the lack of any large-scale, controlled clinical trials. The recent advances in imaging technology also limit the practical utility of older studies that were based on plain radiography for diagnosis and follow-up. Several studies that attempt to stratify patients based on the radiographic appearance of the pars lesion provide data to suggest that there may also be clinical subgroups that should be managed differently. Although the comprehensive answers to questions on the treatment of spondylolysis await further study,
some of the currently available studies on treatment provide useful guidance on management. In a widely referenced study, Steiner and Micheli32 assessed bony healing and clinical outcome in 67 patients with spondylolysis or low-grade spondylolisthesis who were treated with an antilordotic modified Boston brace.32 All of their patients were diagnosed and followed using plain radiography, and 25 of them underwent a planar bone scan. Their patients followed a treatment regimen of brace use for 23 hours per day for 6 months followed by a 6-month weaning period, physical therapy, and allowance for athletic participation in the brace provided that the patient was asymptomatic. Twelve of their patients (23%) showed evidence of bony healing, with the earliest changes appearing at 4 months, and 78% of their patients had good to excellent clinical results including full return to activity and no brace use. The ability to draw reliable conclusions about treatment based on this study, however, is limited by the relatively small number of patients, lack of controls, and the reliance on
C.J. Standaert
104
that may be associated with the potential for achieving bony union in 134 patients imaged with plain radiographs and CT. Treatment included discontinuation of sports and the use of a lumbar corset for 3 months followed by restriction from sports for an additional 3 months if there was evidence of healing on plain films at 3 months from the time of diagnosis. Overall, the radiographic stage of the lesion was the strongest predictor of outcome, with 62% of the early-stage lesions healing and none of the terminal stage defects healing. Other factors associated with a higher chance of bony healing included lesions at the L4 level (versus L5), lesions occurring closer to the vertebral body, and lesions presenting without an associated spondylolisthesis of ⱖ5%. All of these studies found much higher healing rates for unilateral pars defects than for bilateral lesions. There were no data on clinical outcome in any of these studies, nor was SPECT imaging used.
Bracing
Figure 2 (A) MRI scan, T2-weighted axial sequence, showing hyperintense signal in the pedicles bilaterally (arrows) associated with bilateral pars fractures. (B) Corresponding CT scan of the same patient in image (A) showing bilateral pars fractures (arrows) that correlate to the areas of abnormality on the MRI. Note that the actual fractures are appreciated far better on the CT.
plain radiography for diagnosis and assessment of healing. A more recent study by d’Hemecourt and coworkers33 used a similar treatment protocol with similar numbers for clinical outcome, but this study is significantly hampered by a lack of controls, retrospective design, limited data on outcomes, and unclear diagnostic criteria. Several studies have attempted to assess the relationship between bony healing and the radiographic stage of the pars lesion.7,25,26 The authors classified the pars lesions into early, progressive, and terminal stages based on either plain radiography or CT. These studies have shown much higher rates of healing in early-stage lesions with no healing in terminal stage defects.7,25,26 In the most recent of these studies, Fujii and coworkers,7 attempted to assess a number of variables
The use of bracing in the treatment of spondylolysis has been controversial. There are some authors who advocate the routine use of a rigid brace,5,32-34 and there are many other authors who do not recommend the routine use of a rigid brace in the management of these patients.15,21,25,35-37 Bony healing has been shown to occur with the use of either a rigid brace, a soft brace, or no brace, and excellent clinical outcomes are frequently achieved in the absence of bony healing.5,7,15,25,32 It is also important to note that the most consistent finding in biomechanical studies of lumbosacral orthoses is that they limit gross body motion, not intervertebral motion.38 Some studies show that intervertebral motion at the lumbosacral junction can actually be increased by the use of a lumbosacral brace.38-42 The true effect of a brace in a patient with spondylolysis may well be to limit gross motion and, hence, overall physical activity rather than to restrict intervertebral motion in an effort to achieve bony healing. Because the actual effects of brace use on outcome are unclear and the use of a brace may actually impair the achievement of treatment goals for a given patient, the pros and cons of brace use need to be considered in each individual patient.
Surgery Surgical treatment for spondylolysis has generally been reserved for patients who fail conservative care. This clearly represents the vast minority of patients with spondylolysis, and the details of surgical management are not the focus of this article. Overall, surgery is reported to be necessary in about 9% to 15% of cases with spondylolysis and/or lowgrade spondylolisthesis.5,32 Potential indications for surgical intervention include progressive slip, intractable pain, the development of neurologic deficits, and segmental instability associated with pain.43,44 Surgery is generally not required to control pain.15 A recent prospective study found that 82% of 22 athletes undergoing surgical treatment for lumbar spondylolysis were able to return to their previous sports activities.45 There are also case reports of patients being treated with external electrical stimulation after failing other conservative means who then went on to show bony healing.46,47
Lumbar spondylolysis
105 Diagnostic Phase 1. Lumbar radiographs, A/P & lateral 2. Bone scan with SPECT of lumbo-sacral spine
If SPECT consistent with pars lesion
3.
Weeks 12-16
When progressed through acute stage (typically week 16) (If earlier progression is crucial, repeat CT after week 12 & advance faster only if healed) When progressed through recovery stage
5- 7 months
Consider other diagnoses
Limited CT of abnormal level on SPECT, 1.0- 1.5mm slice thickness
Terminal defect in pars
Acute or progressive defect in pars
Weeks 0-12
If not consistent with pars lesion
Rest Phase Rest, including no sports participation or recreational activities Consider bracing if still symptomatic after 2-4 weeks
Rehabilitation Phase Acute Stage Range of motion Low impact aerobic conditioning Neutral spine stabilization
Recovery Stage Range of motion Aerobic conditioning Resistive/ strength training Progressive spinal stabilization Assess kinetic chain & sports technique Functional Stage Aerobic conditioning Resistive/ strength training Dynamic, multi-planar spinal stabilization Sports-specific retraining Skill & technique refinement
Week 0 until pain free with full range of motion
When pain free with full range of motion
When progressed through acute stage
When progressed through recovery stage
Return to Play When completed all of the above 2- 5 months Full, pain-free range of motion Normal strength Appropriate aerobic fitness Adequate spinal awareness and mechanics Able to perform sports-related skills without pain
Figure 3 Recommended management approach for an adolescent athlete with a suspected symptomatic pars lesion/ spondylolysis.
C.J. Standaert
106 The role of this technique in the overall management of patients with spondylolysis is certainly not well defined, however.
Guidelines for Management of Adolescents with Suspected Spondylolysis Based on what is now known about the natural history and pathophysiology of spondylolysis and with finite treatment goals including minimizing exposure to ionizing radiation, minimizing time loss from sports, and allowing for healing where possible, the following strategies are recommended in the management of an adolescent athlete with a suspected symptomatic pars lesion (Fig. 3). In a young athlete with a complaint of low back pain in whom a pars lesion is suspected, plain radiographs with anterior/posterior and lateral views only are initially obtained. This is done to assess for an associated spondylolisthesis, segmentation anomalies, or other gross bony abnormalities. Additional views of the lumbar spine are not obtained routinely. If the plain films do not indicate another diagnosis, a planar bone scan with SPECT imaging of the lumbosacral spine is obtained. If the SPECT scan shows an area of increased uptake consistent with a pars lesion, then a limited CT scan with bone windows, 1.0- to 1.5-mm slice thickness, and stacked sequences is ordered through the area of concern on the SPECT (not through the entire lumbar spine). If the SPECT study is normal, it is unlikely that a symptomatic pars lesion is the primary cause of the patient’s symptoms and other diagnostic testing is pursued as indicated.12,17-19 If a pars lesion is identified on CT that correlates with the abnormality seen on SPECT, then the subsequent treatment is dependent on the radiographic stage of the lesion. For an earlier-stage lesion with either minimal separation and noncorticated or cystic margins, sclerosis without separation, or only stress reaction, there would appear to be a relatively good chance of obtaining a solid bony union, particularly for a unilateral lesion with no associated slip.7,26 These patients are initially treated with rest, including no sports participation and no activity beyond that required for normal daily activities. If pain free after 2 to 3 weeks, this level of activity restriction is continued for a full 3 months, the minimum time required to achieve bony healing.29 Bracing is used if the patient is still symptomatic after 2 to 4 weeks of rest. The patient is informed that the brace is being used predominantly as an additional method of activity restriction rather than as a means of immobilization for healing. The decision on which type of brace to use is dependent on the amount of motion restriction and activity limitation that is desired, given that a more rigid brace provides more substantial limitation of gross motion.40,41 Assuming the patient is asymptomatic at 3 months, a graded rehabilitation program is begun that initially includes neutral spinal stabilization training and low-impact aerobic activity with minimal repetitive spinal motion. The patient is gradually progressed through more aggressive multiplanar
dynamic lumbar stabilization work, strength training, and aerobic conditioning with an emphasis on sports-specific activities and technique.48 The athlete is cleared for return to sport when sufficient cardiovascular conditioning has been attained and the athlete can fully participate in sports activities without symptoms. Most athletes seem to return to full activity at about 5 to 7 months after the time of diagnosis. If the CT scan shows a terminal-stage lesion in the pars that is well corticated or has densely sclerotic margins with significant separation, then bony healing is a much less realistic goal.7,26 These patients are similarly placed on significant activity restriction but only until pain free, at which time they are begun in a rehabilitation program to return them to their sport. Again, bracing is used if symptoms are persisting after 2 to 4 weeks of significant rest with the same caveats as discussed above. At any point in the treatment process, if an individual athlete is not progressing as expected, further investigation is undertaken to evaluate that individual for any alternative diagnoses or psychosocial barriers that may be impacting recovery. Radiographic follow-up is not obtained routinely to assess for healing in athletes with spondylolysis without spondylolisthesis if the patients are asymptomatic, although repeat CT obtained after 3 months may provide information on healing that can be used to address the pace of rehabilitation more precisely. Those athletes with an identified spondylolisthesis may well warrant routine follow-up films, particularly during the rapid growth phase associated with adolescence, but a detailed discussion of management of spondylolisthesis is beyond the scope of this text. The previously described approach to the diagnosis and management of young athletes with spondylolysis is proposed with the knowledge that other practitioners follow different protocols and that our knowledge of this condition is incomplete. Randomized, controlled trials in this area are strongly needed to ascertain the best means of managing individuals with symptomatic lesions of the pars.
References 1. Wiltse LL, Widell EH, Jackson DW: Fatigue Fracture: The basic lesion in isthmic spondylolisthesis. J Bone Joint Surg Am 57:17-22, 1975 2. Fredrickson BE, Baker D, McHolick WJ, et al: The natural history of spondylolysis and spondylolisthesis. J Bone Joint Surg Am 66:699-707, 1984 3. Roche MA, Rowe GG: The incidence of separate neural arch and coincident bone variations: A survey of 4,200 skeletons. Anat Rec 109:233252, 1951 4. Amato ME, Totty WG, Gilula LA: Spondylolysis of the lumbar spine: Demonstration of defects and laminal fragmentation. Radiology 153: 627-629, 1984 5. Blanda J, Bethem D, Moats W, et al: Defects of pars interarticularis in athletes: A protocol for nonoperative treatment. J Spinal Disord 6:406411, 1993 6. Soler T, Calderon C: The prevalence of spondylolysis in the Spanish elite athlete. Am J Sports Med 28:57-62, 2000 7. Fujii K, Katoh S, Sairyo K, et al: Union of defects in the pars interarticularis of the lumbar spine in children and adolescents. The radiologic outcome after conservative treatment. J Bone Joint Surg Br 86:225-231, 2004 8. Jackson DW, Wiltse LL, Cirincione RJ: Spondylolysis in the female gymnast. Clin Orthop Relat Res 117:658-673, 1976
Lumbar spondylolysis 9. Rossi F, Dragoni S: The prevalence of spondylolysis and spondylolisthesis in symptomatic elite athletes: Radiographic findings. Radiography 7:37-42, 2001 10. Micheli LJ, Wood R: Back pain in young athletes: Significant differences from adults in causes and patterns. Arch Pediatr Adolesc Med 149:1518, 1995 11. Anderson K, Sarwark JF, Conway JJ, et al: Quantitative assessment with SPECT imaging of stress injuries of the pars interarticularis and response to bracing. J Ped Orthop 20:28-33, 2000 12. Bellah RD, Summerville DA, Treves ST, et al: Low back pain in adolescent athletes: Detection of stress injury to the pars interarticularis with SPECT. Radiology 180:509-512, 1991 13. Bodner RJ, Heyman S, Drummond DS, et al: The use of single photon emission computed tomography (SPECT) in the diagnosis of low back pain in young patients. Spine 13:1155-1160, 1988 14. Elliott S, Hutson MA, Wastie ML: Bone scintigraphy in the assessment of spondylolysis in patients attending a sports injury clinic. Clin Radiol 39:269-272, 1988 15. Jackson DW, Wiltse LL, Dingeman RD, et al: Stress reactions involving the pars interarticularis in young athletes. Am J Sports Med 9:304-312, 1981 16. Stretch RA, Botha T, Chandler S, et al: Back injuries in young fast bowlers—A radiologic investigation of the healing of spondylolysis and pedicle sclerosis. S Afr Med J 93:611-616, 2003 17. Lowe J, Schachner E, Hirschberg E, et al: Significance of bone scintigraphy in symptomatic spondylolysis. Spine 9:653-655, 1984 18. Collier BD, Johnson RP, Carrera GF, et al: Painful spondylolysis or spondylolisthesis studied by radiography and single photon emission computed tomography. Radiology 154:207-211, 1985 19. Lusins JO, Elting JJ, Cicoria AD, et al: SPECT evaluation of lumbar spondylolysis and spondylolisthesis. Spine 19:608-612, 1994 20. Raby N, Mathews S: Symptomatic spondylolysis: Correlation of CT and SPECT with clinical outcome. Clin Radiol 48:97-99, 1993 21. Congeni J, McCulloch J, Swanson K: Lumbar spondylolysis: A study of natural progression in athletes. Am J Sports Med 25:2148-2253, 1997 22. Harvey CJ, Richenberg JL, Saifuddin A, et al: Pictorial review: The radiological investigation of lumbar spondylolysis. Clin Radiol 53:723728, 1998 23. Saifuddin A, White J, Tucker S, et al: Orientation of lumbar pars defects: Implications for radiological detection and surgical management. J Bone Joint Surg Br 80:208-211, 1998 24. Teplick JG, Laffey PA, Berman A: Diagnosis and evaluation of spondylolisthesis and/or spondylolysis on axial CT. Am J Neuroradiol 7:479-491, 1986 25. Katoh S, Ikata T, Fujii K: Factors influencing on union of spondylolysis in children and adolescents. Proceedings and abstracts from North American Spine Society 12th annual meeting, New York, NY, 1997, p 222 26. Morita T, Ikata T, Katoh S, et al: Lumbar spondylolysis in children and adolescents. J Bone Joint Surg Br 77:620-625, 1995 27. Campbell RSD, Grainger AJ: Optimization of MRI pulse sequences to visualize the normal pars interarticularis. Clin Radiol 54:63-68, 1999
107 28. Udeshi UL, Reeves D: Routine thin slice MRI effectively demonstrates the lumbar pars interarticularis. Clin Radiol 54:615-619, 1999 29. Yamane T, Yoshida T, Mimatsu K: Early diagnosis of lumbar spondylolysis by MRI. J Bone Joint Surg Br 75:764-768, 1993 30. Hollenberg GM, Beattie PF, Meyers SP, et al: Stress reactions of the lumbar pars interarticularis. The development of a new MRI classification system. Spine 27:181-186, 2002 31. Lighting up spondylolysis to identify stress fractures with the capacity for healing. The BackLetter 18:121-131, 2003 32. Steiner ME, Micheli LJ: Treatment of symptomatic spondylolysis and spondylolisthesis with the modified Boston brace. Spine 10:937-943, 1985 33. d’Hemecourt PA, Zurakowski D, Kriemler S, et al: Spondylolysis: Returning the athlete to sports participation with brace treatment. Orthopedics 23:653-657, 2002 34. Letts M, MacDonald P: Sports injuries to the pediatric spine. Spine: State of the Art Reviews 4:49-83, 1990 35. Herman MJ, Pizzutillo PD, Cavalier R: Spondylolysis and spondylolisthesis in the child and adolescent athlete. Othop Clin North Am 34: 461-467, 2003 36. Logroscino G, Mazza O, Aulisa AG, et al: Spondylolysis and spondylolisthesis in the pediatric and adolescent population. Childs Nerv Syst 17:644-655, 2001 37. Moeller JL, Rifat SF: Spondylolysis in active adolescents: Expediting return to play. Phys Sports Med 29:27-32, 2001 38. Cholewicki J, Alvi K, Silfies SP, et al: Comparison of motion restriction and trunk stiffness provided by three thoracolumosacral orthoses (TLSOs). J Spinal Disord Tech 16:461-468, 2003 39. Axelsson P, Johnsson R, Stromqvist B: Effect of lumbar orthosis on intervertebral mobility. Spine 17:678-681, 1992 40. Calmels P, Fayolle-Minon ??: An update on orthotic devices for the lumbar spine based on a review of the literature. Rev Rheumatol (Engl Ed) 63:285-291, 1996 41. Lantz SA, Schultz AB: Lumbar spine orthosis wearing I: Restriction of gross body motions. Spine 11:834-837, 1986 42. Tuong NH, Dansereau J, Maurais G, et al: Three-dimensional evaluation of lumbar othosis effects on spinal behavior. J Rehabil Res Dev 35:34-42, 1998 43. Ciullo JV, Jackson DW: Pars interarticularis stress reaction, spondylolysis, and spondylolisthesis in gymnasts. Clin Sports Med 4:95-110, 1985 44. Shook JE: Spondylolysis and spondylolisthesis: Spine: State of the Art Reviews 4:185-197, 1990 45. Debnath UU, Freeman JC, Gregory P, et al: Clinical outcomeand return to sport after the surgical treatment of spondylolysis in young athletes. J Bone Joint Surg Br 85:244-249, 2003 46. Fellander-Tsai L, Micheli LJ: Treatment of spondylolysis with external stimulation and bracing in adolescent athletes: A report of two cases. Clin J Sport Med 8:232-234, 1998 47. Maharam LG, Sharkey I: Electrical stimulation of acute spondylolysis: 3 cases. Med Sci Sports Exerc 24:S38, 1992 (suppl) 48. Standaert CJ, Herring SA, Pratt TW: Rehabilitation of the lumbar spine in the athlete. Curr Sports Med Rep 3:35-40, 2004
S
pondylolysis is defined as a defect in the pars interarticularis of the neural arch and represents a particular clinical problem in adolescent athletes. Although there is a great deal of general agreement that spondylolysis represents a fatigue fracture of the neural arch occurring as a result of repetitive force exposure,1 there is substantial disagreement among authors on the optimal approaches to radiographic assessment and treatment of this disorder, in large part related to the lack of any real controlled trials on the diagnosis or management of adolescent athletes with symptomatic pars lesions. Given this, it is important to understand the literature that is available to develop appropriate diagnostic and treatment strategies for these patients. This article will address these issues and present a framework for a rational approach to the diagnosis and management of adolescent athletes with spondylolysis.
Epidemiology Lesions of the pars are frequent findings on plain radiographs in the general population and are much more commonly seen
Puget Sound Sports and Spine Physicians, Seattle, WA. Department of Rehabilitation Medicine, University of Washington, Seattle, WA. Address reprint requests to Christopher J. Standaert, MD, Puget Sound Sports and Spine Physicians, 1600 E. Jefferson, Suite 401, Seattle, WA 98122. E-mail: [email protected]
1060-1872/05/$-see front matter © 2005 Elsevier Inc. All rights reserved. doi:10.1053/j.otsm.2005.08.004
in populations of adolescent athletes. Fredrickson and coworkers2 prospectively studied 500 first-grade students with plain radiographs and found an overall incidence of spondylolysis of 4.4% at age 6. All of these lesions occurred without any symptoms. This number increased to 5.2% by age 12 and 6% by adulthood. Roche and Rowe3 studied 4,200 cadaveric spines and found an overall incidence of 4.2%. This number varied within subgroups of the population, however, with rates of 6.4% for white males, 2.8% for black males, 2.3% for white females, and 1.1% for black females. There was no significant change in these rates with increasing age from 20 to 80 years old. The vast majority of spondylolytic defects occur at L5 (85%-95%), with L4 being the next most commonly affected level (5%-15%). More proximal lumbar levels are affected much less frequently.2-7 The incidence of spondylolysis seems to be higher in the young athletic population than in the general population. Jackson and coworkers8 studied 100 young female gymnasts with plain radiographs and found spondylolysis in 11%. In a review of 3,152 elite Spanish athletes, Soler and Calderon6 found an overall rate of spondylolysis of 8.02% for the group as a whole based on plain radiographs. They noted higher rates of spondylolysis in gymnasts, weight lifters, throwing track and field athletes, and rowers. Rossi and Dragoni9 have published the results of a study of 4,243 young athletes assessed with plain radiographs. All the athletes had complaints of low back pain and were evaluated between 1962 and 1998 with studies that included anteroposterior, lateral, 101
102 and oblique films. The authors found that 13.9% of the athletes had evidence of spondylolysis on plain radiographs and that 47.5% of these had a concurrent spondylolisthesis. Again, some sports had much higher rates of spondylolysis identified than others, including diving, wrestling, weight lifting, track and field, and gymnastics. In a study by Micheli and Wood,10 spondylolysis was clearly the most frequent diagnosis made in adolescent athletes presenting to a sports medicine clinic with low back pain and was seen far more frequently in these athletes than in a comparative group of adults with low back pain.
Diagnostic Imaging Multiple imaging modalities are available for use in the diagnosis of a patient with a suspected pars lesion, notably plain radiography, nuclear imaging, computed tomography scan (CT), and magnetic resonance imaging (MRI). There is limited available data comparing these studies directly in the diagnosis of spondylolysis; thus, it is difficult to identify the true relative sensitivity and specificity of these tests. The degree and quality of literature on each of these modalities in the setting of spondylolysis is variable as well, with MRI having the least available data when compared with the other types of imaging studies. Given the frequency with which pars defects are identified radiographically in asymptomatic individuals, the goal of diagnostic imaging is not just to identify a pars lesion but also to find indications that that the lesion is likely to be symptomatic. Generally speaking, multiple imaging modalities are usually required to establish an accurate diagnosis. Plain radiography has been an important diagnostic tool for spondylolysis for some time. The defect in isthmic spondylolysis is visualized as a lucency in the region of the pars interarticularis. The lesion is commonly described as having the appearance of a collar or a broken neck on the “Scotty dog” seen in lateral oblique radiographs. Visualizing a defect in the pars on plain radiographs can be difficult, however, and frequently requires multiple views of the lumbosacral spine. In a study by Amato and coworkers,4 the single most sensitive view was the lateral spot view of the lumbosacral junction, which revealed the lesion in 84% of their cases. When just using anterior/posterior, lateral, and lateral oblique views, roughly 19% of the pars defects identified were seen only on the lateral oblique views. Although widely used and studied, plain radiography has been shown to be relatively insensitive compared with newer imaging modalities. In the last 20 years, multiple studies using radionuclide imaging have shown that bone scan and, particularly, single-photon emission computed tomography (SPECT) offer many advantages over isolated plain radiographs in the diagnosis of spondylolysis. Several studies have shown that SPECT is significantly more sensitive than both plain films and planar bone scan11-16 A study by Anderson and coworkers,11 for example, found that, when compared with SPECT, plain radiography failed to demonstrate the pars lesion in 53% of their patients and planar bone scan in 19%. In addition to simply being more sensitive in the identifica-
C.J. Standaert tion of pars lesions than plain radiography, there is also evidence that bone scan or SPECT may be helpful with the crucial task of identifying symptomatic lesions. Studies by Elliot and coworkers14 and Lowe and coworkers17 both suggested that a positive bone scan correlates with a symptomatic lesion. Collier and coworkers,18 Lusins and coworkers,19 and Raby and Mathews,20 all using different lines of research, similarly concluded that a positive SPECT scan correlated strongly with a symptomatic lesion. A significant limitation of nuclear imaging is that, although seemingly quite sensitive in the identification of pars lesions, the specificity of this type of imaging is more suspect. Potential abnormalities that may result in an abnormal SPECT that would otherwise be consistent with spondylolysis include facet arthropathy or fracture, infection, and osteoid osteoma. Additional imaging, particularly with a CT scan, is generally required to clarify the bony abnormality in a patient with a positive SPECT study. Like radionuclide imaging, CT scan has been shown to be more sensitive than plain radiography in revealing pars lesions.21-24 Some authors have used CT as their “gold standard,”7,21 although direct comparisons to SPECT are few and there are little to no data on the correlation between the findings on CT scan and symptoms or clinical outcome, as there has been for nuclear imaging. There is also debate as to the optimal means of data acquisition with CT scan, particularly regarding slice thickness and the angle of the gantry. Some recent studies have used CT scan to “stage” pars defects (Fig. 1) and have noted clear correlations between the radiographic stage of the lesion and the chance of obtaining a bony union with conservative management.7,25,26 The role of MRI in the diagnosis of pars lesions has been controversial. Its efficacy in visualizing the pars had proven somewhat problematic in early studies, but more recent work with improved technical approaches has proven more useful22,27,28 (Fig. 2). MRI clearly offers advantages over SPECT and CT scan in terms of revealing other types of pathology present in the lumbar spine, and the lack of ionizing radiation with MRI may also contribute to this being a particularly desirable modality in studying pars lesions, especially in the female adolescent population.22 Yamane and coworkers29 compared MRI with CT scan and found that MRI may be helpful in identifying lesions in the pars before they are noted on CT and, thus, may have the potential for identifying stress lesions early in their clinical course. There was no comparison to SPECT included in this study, however, nor any data on clinical correlation to the findings on MRI. Hollenberg and coworkers30 recently presented a classification system for findings in the pars interarticularis based on the appearance of the pars on MRI graded on a 0 to 4 scale with defined criteria for each grade thought to correspond with varying types of injuries or pathological states of the pars. Although the authors believed that their classification system was reliable, the clinical utility of this system is unclear. Unfortunately, there was no comparison of these studies to either SPECT or CT scan, no clinical data on outcome, no clear means of establishing pathological correlates to the findings, and no discussion of the prevalence of these findings in a
Lumbar spondylolysis
103
Figure 1 (A) CT scan showing an early-stage pars lesion (arrow) associated with sclerosis and an incomplete fracture line but no significant separation, cortication, or cystic change. (B) CT scan showing a progressive stage pars lesion (arrow) associated with sclerosis, fracture with minimal separation, and cyst formation. There is no cortication of the fracture margins. (C) CT scan showing a terminal stage pars lesion (arrow) with separation and clearly defined, corticated margins.
normal control group. Takata and colleagues31 recently presented an as-yet-unpublished study suggesting that the presence of high-intensity signal in the pedicle on MRI is a predictor of bony healing. Although promising, the role of MRI in the diagnosis and treatment of spondylolysis is not yet clarified in the available literature.
Treatment Studies on the efficacy of various treatment approaches for adolescent athletes with symptomatic spondylolysis are similarly muddied by the lack of any large-scale, controlled clinical trials. The recent advances in imaging technology also limit the practical utility of older studies that were based on plain radiography for diagnosis and follow-up. Several studies that attempt to stratify patients based on the radiographic appearance of the pars lesion provide data to suggest that there may also be clinical subgroups that should be managed differently. Although the comprehensive answers to questions on the treatment of spondylolysis await further study,
some of the currently available studies on treatment provide useful guidance on management. In a widely referenced study, Steiner and Micheli32 assessed bony healing and clinical outcome in 67 patients with spondylolysis or low-grade spondylolisthesis who were treated with an antilordotic modified Boston brace.32 All of their patients were diagnosed and followed using plain radiography, and 25 of them underwent a planar bone scan. Their patients followed a treatment regimen of brace use for 23 hours per day for 6 months followed by a 6-month weaning period, physical therapy, and allowance for athletic participation in the brace provided that the patient was asymptomatic. Twelve of their patients (23%) showed evidence of bony healing, with the earliest changes appearing at 4 months, and 78% of their patients had good to excellent clinical results including full return to activity and no brace use. The ability to draw reliable conclusions about treatment based on this study, however, is limited by the relatively small number of patients, lack of controls, and the reliance on
C.J. Standaert
104
that may be associated with the potential for achieving bony union in 134 patients imaged with plain radiographs and CT. Treatment included discontinuation of sports and the use of a lumbar corset for 3 months followed by restriction from sports for an additional 3 months if there was evidence of healing on plain films at 3 months from the time of diagnosis. Overall, the radiographic stage of the lesion was the strongest predictor of outcome, with 62% of the early-stage lesions healing and none of the terminal stage defects healing. Other factors associated with a higher chance of bony healing included lesions at the L4 level (versus L5), lesions occurring closer to the vertebral body, and lesions presenting without an associated spondylolisthesis of ⱖ5%. All of these studies found much higher healing rates for unilateral pars defects than for bilateral lesions. There were no data on clinical outcome in any of these studies, nor was SPECT imaging used.
Bracing
Figure 2 (A) MRI scan, T2-weighted axial sequence, showing hyperintense signal in the pedicles bilaterally (arrows) associated with bilateral pars fractures. (B) Corresponding CT scan of the same patient in image (A) showing bilateral pars fractures (arrows) that correlate to the areas of abnormality on the MRI. Note that the actual fractures are appreciated far better on the CT.
plain radiography for diagnosis and assessment of healing. A more recent study by d’Hemecourt and coworkers33 used a similar treatment protocol with similar numbers for clinical outcome, but this study is significantly hampered by a lack of controls, retrospective design, limited data on outcomes, and unclear diagnostic criteria. Several studies have attempted to assess the relationship between bony healing and the radiographic stage of the pars lesion.7,25,26 The authors classified the pars lesions into early, progressive, and terminal stages based on either plain radiography or CT. These studies have shown much higher rates of healing in early-stage lesions with no healing in terminal stage defects.7,25,26 In the most recent of these studies, Fujii and coworkers,7 attempted to assess a number of variables
The use of bracing in the treatment of spondylolysis has been controversial. There are some authors who advocate the routine use of a rigid brace,5,32-34 and there are many other authors who do not recommend the routine use of a rigid brace in the management of these patients.15,21,25,35-37 Bony healing has been shown to occur with the use of either a rigid brace, a soft brace, or no brace, and excellent clinical outcomes are frequently achieved in the absence of bony healing.5,7,15,25,32 It is also important to note that the most consistent finding in biomechanical studies of lumbosacral orthoses is that they limit gross body motion, not intervertebral motion.38 Some studies show that intervertebral motion at the lumbosacral junction can actually be increased by the use of a lumbosacral brace.38-42 The true effect of a brace in a patient with spondylolysis may well be to limit gross motion and, hence, overall physical activity rather than to restrict intervertebral motion in an effort to achieve bony healing. Because the actual effects of brace use on outcome are unclear and the use of a brace may actually impair the achievement of treatment goals for a given patient, the pros and cons of brace use need to be considered in each individual patient.
Surgery Surgical treatment for spondylolysis has generally been reserved for patients who fail conservative care. This clearly represents the vast minority of patients with spondylolysis, and the details of surgical management are not the focus of this article. Overall, surgery is reported to be necessary in about 9% to 15% of cases with spondylolysis and/or lowgrade spondylolisthesis.5,32 Potential indications for surgical intervention include progressive slip, intractable pain, the development of neurologic deficits, and segmental instability associated with pain.43,44 Surgery is generally not required to control pain.15 A recent prospective study found that 82% of 22 athletes undergoing surgical treatment for lumbar spondylolysis were able to return to their previous sports activities.45 There are also case reports of patients being treated with external electrical stimulation after failing other conservative means who then went on to show bony healing.46,47
Lumbar spondylolysis
105 Diagnostic Phase 1. Lumbar radiographs, A/P & lateral 2. Bone scan with SPECT of lumbo-sacral spine
If SPECT consistent with pars lesion
3.
Weeks 12-16
When progressed through acute stage (typically week 16) (If earlier progression is crucial, repeat CT after week 12 & advance faster only if healed) When progressed through recovery stage
5- 7 months
Consider other diagnoses
Limited CT of abnormal level on SPECT, 1.0- 1.5mm slice thickness
Terminal defect in pars
Acute or progressive defect in pars
Weeks 0-12
If not consistent with pars lesion
Rest Phase Rest, including no sports participation or recreational activities Consider bracing if still symptomatic after 2-4 weeks
Rehabilitation Phase Acute Stage Range of motion Low impact aerobic conditioning Neutral spine stabilization
Recovery Stage Range of motion Aerobic conditioning Resistive/ strength training Progressive spinal stabilization Assess kinetic chain & sports technique Functional Stage Aerobic conditioning Resistive/ strength training Dynamic, multi-planar spinal stabilization Sports-specific retraining Skill & technique refinement
Week 0 until pain free with full range of motion
When pain free with full range of motion
When progressed through acute stage
When progressed through recovery stage
Return to Play When completed all of the above 2- 5 months Full, pain-free range of motion Normal strength Appropriate aerobic fitness Adequate spinal awareness and mechanics Able to perform sports-related skills without pain
Figure 3 Recommended management approach for an adolescent athlete with a suspected symptomatic pars lesion/ spondylolysis.
C.J. Standaert
106 The role of this technique in the overall management of patients with spondylolysis is certainly not well defined, however.
Guidelines for Management of Adolescents with Suspected Spondylolysis Based on what is now known about the natural history and pathophysiology of spondylolysis and with finite treatment goals including minimizing exposure to ionizing radiation, minimizing time loss from sports, and allowing for healing where possible, the following strategies are recommended in the management of an adolescent athlete with a suspected symptomatic pars lesion (Fig. 3). In a young athlete with a complaint of low back pain in whom a pars lesion is suspected, plain radiographs with anterior/posterior and lateral views only are initially obtained. This is done to assess for an associated spondylolisthesis, segmentation anomalies, or other gross bony abnormalities. Additional views of the lumbar spine are not obtained routinely. If the plain films do not indicate another diagnosis, a planar bone scan with SPECT imaging of the lumbosacral spine is obtained. If the SPECT scan shows an area of increased uptake consistent with a pars lesion, then a limited CT scan with bone windows, 1.0- to 1.5-mm slice thickness, and stacked sequences is ordered through the area of concern on the SPECT (not through the entire lumbar spine). If the SPECT study is normal, it is unlikely that a symptomatic pars lesion is the primary cause of the patient’s symptoms and other diagnostic testing is pursued as indicated.12,17-19 If a pars lesion is identified on CT that correlates with the abnormality seen on SPECT, then the subsequent treatment is dependent on the radiographic stage of the lesion. For an earlier-stage lesion with either minimal separation and noncorticated or cystic margins, sclerosis without separation, or only stress reaction, there would appear to be a relatively good chance of obtaining a solid bony union, particularly for a unilateral lesion with no associated slip.7,26 These patients are initially treated with rest, including no sports participation and no activity beyond that required for normal daily activities. If pain free after 2 to 3 weeks, this level of activity restriction is continued for a full 3 months, the minimum time required to achieve bony healing.29 Bracing is used if the patient is still symptomatic after 2 to 4 weeks of rest. The patient is informed that the brace is being used predominantly as an additional method of activity restriction rather than as a means of immobilization for healing. The decision on which type of brace to use is dependent on the amount of motion restriction and activity limitation that is desired, given that a more rigid brace provides more substantial limitation of gross motion.40,41 Assuming the patient is asymptomatic at 3 months, a graded rehabilitation program is begun that initially includes neutral spinal stabilization training and low-impact aerobic activity with minimal repetitive spinal motion. The patient is gradually progressed through more aggressive multiplanar
dynamic lumbar stabilization work, strength training, and aerobic conditioning with an emphasis on sports-specific activities and technique.48 The athlete is cleared for return to sport when sufficient cardiovascular conditioning has been attained and the athlete can fully participate in sports activities without symptoms. Most athletes seem to return to full activity at about 5 to 7 months after the time of diagnosis. If the CT scan shows a terminal-stage lesion in the pars that is well corticated or has densely sclerotic margins with significant separation, then bony healing is a much less realistic goal.7,26 These patients are similarly placed on significant activity restriction but only until pain free, at which time they are begun in a rehabilitation program to return them to their sport. Again, bracing is used if symptoms are persisting after 2 to 4 weeks of significant rest with the same caveats as discussed above. At any point in the treatment process, if an individual athlete is not progressing as expected, further investigation is undertaken to evaluate that individual for any alternative diagnoses or psychosocial barriers that may be impacting recovery. Radiographic follow-up is not obtained routinely to assess for healing in athletes with spondylolysis without spondylolisthesis if the patients are asymptomatic, although repeat CT obtained after 3 months may provide information on healing that can be used to address the pace of rehabilitation more precisely. Those athletes with an identified spondylolisthesis may well warrant routine follow-up films, particularly during the rapid growth phase associated with adolescence, but a detailed discussion of management of spondylolisthesis is beyond the scope of this text. The previously described approach to the diagnosis and management of young athletes with spondylolysis is proposed with the knowledge that other practitioners follow different protocols and that our knowledge of this condition is incomplete. Randomized, controlled trials in this area are strongly needed to ascertain the best means of managing individuals with symptomatic lesions of the pars.
References 1. Wiltse LL, Widell EH, Jackson DW: Fatigue Fracture: The basic lesion in isthmic spondylolisthesis. J Bone Joint Surg Am 57:17-22, 1975 2. Fredrickson BE, Baker D, McHolick WJ, et al: The natural history of spondylolysis and spondylolisthesis. J Bone Joint Surg Am 66:699-707, 1984 3. Roche MA, Rowe GG: The incidence of separate neural arch and coincident bone variations: A survey of 4,200 skeletons. Anat Rec 109:233252, 1951 4. Amato ME, Totty WG, Gilula LA: Spondylolysis of the lumbar spine: Demonstration of defects and laminal fragmentation. Radiology 153: 627-629, 1984 5. Blanda J, Bethem D, Moats W, et al: Defects of pars interarticularis in athletes: A protocol for nonoperative treatment. J Spinal Disord 6:406411, 1993 6. Soler T, Calderon C: The prevalence of spondylolysis in the Spanish elite athlete. Am J Sports Med 28:57-62, 2000 7. Fujii K, Katoh S, Sairyo K, et al: Union of defects in the pars interarticularis of the lumbar spine in children and adolescents. The radiologic outcome after conservative treatment. J Bone Joint Surg Br 86:225-231, 2004 8. Jackson DW, Wiltse LL, Cirincione RJ: Spondylolysis in the female gymnast. Clin Orthop Relat Res 117:658-673, 1976
Lumbar spondylolysis 9. Rossi F, Dragoni S: The prevalence of spondylolysis and spondylolisthesis in symptomatic elite athletes: Radiographic findings. Radiography 7:37-42, 2001 10. Micheli LJ, Wood R: Back pain in young athletes: Significant differences from adults in causes and patterns. Arch Pediatr Adolesc Med 149:1518, 1995 11. Anderson K, Sarwark JF, Conway JJ, et al: Quantitative assessment with SPECT imaging of stress injuries of the pars interarticularis and response to bracing. J Ped Orthop 20:28-33, 2000 12. Bellah RD, Summerville DA, Treves ST, et al: Low back pain in adolescent athletes: Detection of stress injury to the pars interarticularis with SPECT. Radiology 180:509-512, 1991 13. Bodner RJ, Heyman S, Drummond DS, et al: The use of single photon emission computed tomography (SPECT) in the diagnosis of low back pain in young patients. Spine 13:1155-1160, 1988 14. Elliott S, Hutson MA, Wastie ML: Bone scintigraphy in the assessment of spondylolysis in patients attending a sports injury clinic. Clin Radiol 39:269-272, 1988 15. Jackson DW, Wiltse LL, Dingeman RD, et al: Stress reactions involving the pars interarticularis in young athletes. Am J Sports Med 9:304-312, 1981 16. Stretch RA, Botha T, Chandler S, et al: Back injuries in young fast bowlers—A radiologic investigation of the healing of spondylolysis and pedicle sclerosis. S Afr Med J 93:611-616, 2003 17. Lowe J, Schachner E, Hirschberg E, et al: Significance of bone scintigraphy in symptomatic spondylolysis. Spine 9:653-655, 1984 18. Collier BD, Johnson RP, Carrera GF, et al: Painful spondylolysis or spondylolisthesis studied by radiography and single photon emission computed tomography. Radiology 154:207-211, 1985 19. Lusins JO, Elting JJ, Cicoria AD, et al: SPECT evaluation of lumbar spondylolysis and spondylolisthesis. Spine 19:608-612, 1994 20. Raby N, Mathews S: Symptomatic spondylolysis: Correlation of CT and SPECT with clinical outcome. Clin Radiol 48:97-99, 1993 21. Congeni J, McCulloch J, Swanson K: Lumbar spondylolysis: A study of natural progression in athletes. Am J Sports Med 25:2148-2253, 1997 22. Harvey CJ, Richenberg JL, Saifuddin A, et al: Pictorial review: The radiological investigation of lumbar spondylolysis. Clin Radiol 53:723728, 1998 23. Saifuddin A, White J, Tucker S, et al: Orientation of lumbar pars defects: Implications for radiological detection and surgical management. J Bone Joint Surg Br 80:208-211, 1998 24. Teplick JG, Laffey PA, Berman A: Diagnosis and evaluation of spondylolisthesis and/or spondylolysis on axial CT. Am J Neuroradiol 7:479-491, 1986 25. Katoh S, Ikata T, Fujii K: Factors influencing on union of spondylolysis in children and adolescents. Proceedings and abstracts from North American Spine Society 12th annual meeting, New York, NY, 1997, p 222 26. Morita T, Ikata T, Katoh S, et al: Lumbar spondylolysis in children and adolescents. J Bone Joint Surg Br 77:620-625, 1995 27. Campbell RSD, Grainger AJ: Optimization of MRI pulse sequences to visualize the normal pars interarticularis. Clin Radiol 54:63-68, 1999
107 28. Udeshi UL, Reeves D: Routine thin slice MRI effectively demonstrates the lumbar pars interarticularis. Clin Radiol 54:615-619, 1999 29. Yamane T, Yoshida T, Mimatsu K: Early diagnosis of lumbar spondylolysis by MRI. J Bone Joint Surg Br 75:764-768, 1993 30. Hollenberg GM, Beattie PF, Meyers SP, et al: Stress reactions of the lumbar pars interarticularis. The development of a new MRI classification system. Spine 27:181-186, 2002 31. Lighting up spondylolysis to identify stress fractures with the capacity for healing. The BackLetter 18:121-131, 2003 32. Steiner ME, Micheli LJ: Treatment of symptomatic spondylolysis and spondylolisthesis with the modified Boston brace. Spine 10:937-943, 1985 33. d’Hemecourt PA, Zurakowski D, Kriemler S, et al: Spondylolysis: Returning the athlete to sports participation with brace treatment. Orthopedics 23:653-657, 2002 34. Letts M, MacDonald P: Sports injuries to the pediatric spine. Spine: State of the Art Reviews 4:49-83, 1990 35. Herman MJ, Pizzutillo PD, Cavalier R: Spondylolysis and spondylolisthesis in the child and adolescent athlete. Othop Clin North Am 34: 461-467, 2003 36. Logroscino G, Mazza O, Aulisa AG, et al: Spondylolysis and spondylolisthesis in the pediatric and adolescent population. Childs Nerv Syst 17:644-655, 2001 37. Moeller JL, Rifat SF: Spondylolysis in active adolescents: Expediting return to play. Phys Sports Med 29:27-32, 2001 38. Cholewicki J, Alvi K, Silfies SP, et al: Comparison of motion restriction and trunk stiffness provided by three thoracolumosacral orthoses (TLSOs). J Spinal Disord Tech 16:461-468, 2003 39. Axelsson P, Johnsson R, Stromqvist B: Effect of lumbar orthosis on intervertebral mobility. Spine 17:678-681, 1992 40. Calmels P, Fayolle-Minon ??: An update on orthotic devices for the lumbar spine based on a review of the literature. Rev Rheumatol (Engl Ed) 63:285-291, 1996 41. Lantz SA, Schultz AB: Lumbar spine orthosis wearing I: Restriction of gross body motions. Spine 11:834-837, 1986 42. Tuong NH, Dansereau J, Maurais G, et al: Three-dimensional evaluation of lumbar othosis effects on spinal behavior. J Rehabil Res Dev 35:34-42, 1998 43. Ciullo JV, Jackson DW: Pars interarticularis stress reaction, spondylolysis, and spondylolisthesis in gymnasts. Clin Sports Med 4:95-110, 1985 44. Shook JE: Spondylolysis and spondylolisthesis: Spine: State of the Art Reviews 4:185-197, 1990 45. Debnath UU, Freeman JC, Gregory P, et al: Clinical outcomeand return to sport after the surgical treatment of spondylolysis in young athletes. J Bone Joint Surg Br 85:244-249, 2003 46. Fellander-Tsai L, Micheli LJ: Treatment of spondylolysis with external stimulation and bracing in adolescent athletes: A report of two cases. Clin J Sport Med 8:232-234, 1998 47. Maharam LG, Sharkey I: Electrical stimulation of acute spondylolysis: 3 cases. Med Sci Sports Exerc 24:S38, 1992 (suppl) 48. Standaert CJ, Herring SA, Pratt TW: Rehabilitation of the lumbar spine in the athlete. Curr Sports Med Rep 3:35-40, 2004