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Spondylolysis is a defect of the pars interarticularis of vertebrae, most commonly seen at L5 and L4. The etiology of spondylolysis and isthmic spondylolisthesis is generally considered to be a result of repetitive mechanical stress to the weak portion of the vertebrae. A higher incidence of spondylolysis is observed in young athletes. Symptomatic spondylolysis can be successfully treated conservatively, but there is currently a limited consensus on treatment modalities and a lack of large-scale clinical trials.
The purpose of the present study was to investigate the optimal treatment algorithm for symptomatic spondylolysis in adolescent athletes and evaluate the functional outcomes of those undergoing the nonoperative treatment.
A retrospective review.
Two hundred one adolescent patients ranging from age 10 to 19 involved in athletics
Injury characteristics (age, mechanism, time), sports played, bone stimulator use, bony healing at 3 months on computed tomography (CT) scans, return to sports, corticosteroid injection use.
Two hundred one adolescent athlete patients (62 females and 139 males) diagnosed with spondylolysis between 2007 and 2019 were retrospectively reviewed. Diagnosis was based on plain radiography followed by magnetic resonance imaging. All patients were treated conservatively with cessation of sports activity, thoracolumbosacral orthosis, and external bone stimulator for three months after diagnosis. CT scans were obtained for the 3-month follow-up visits to assess bony healing. Subsequently the patients received 6 weeks of rehabilitation focused on core strengthening. Symptomatic patients after the treatment were referred for steroid injections and continued with the rehabilitation protocol.
The most common age of injury was 15 years old, following a strong normal distribution. The most commonly played sport was football, followed by baseball/softball. The primary mechanism of injury was weight training closely followed by a football injury. The first quarter of the calendar year had the highest incidence of injuries with the most injuries occurring in March and the least occurring in December. One hundred fifty-two athletes reported using bone stimulators as prescribed, and these patients showed a significantly higher rate of bony healing on follow-up CT scans than those who did not use bone stimulators. One hundred ninety-seven patients (98%) returned to sports or similar level of activities. Thirty-seven patients (18%) received facet or epidural steroid injections due to continued pain and one patient underwent a surgical procedure. Follow-up CT scans showed 49.8% bony healing.
Conservative treatment of spondylolysis in adolescent athletes with cessation of sports, thoracolumbosacral orthosis, and bone stimulator followed by rehabilitation was associated with excellent outcomes in terms of return to sports.
] and can result in isthmic spondylolisthesis, which is the forward displacement of the upper vertebrae and separation of the anterior aspects of the vertebra from its neural arch due to defects in the pars interarticularis [
The etiology of spondylolysis and isthmic spondylolisthesis has been debated for many decades. The congenital theory was disproved in 1953 when Rowe and Roche found no neural arch defect in 500 infant cadavers [
]. Thus, this study aims to provide an optimal treatment algorithm for spondylolysis in young athletes and functional outcomes of those who undergo the treatment algorithm.
The charts and images of 201 patients, who presented with lower back pain and diagnosed with lumbar spondylolysis from 2007 to 2019, were retrospectively reviewed. The study population consisted of adolescents ranging from ages 10 to 19 involved in athletics and included 62 females and 139 males with pars interarticularis defects. All of these patients were seen and evaluated at a single institution. The initial diagnosis and grade of fracture was determined by plain radiography, followed by magnetic resonance imaging (MRI) for more accurate diagnosis. Computed tomography (CT) scans were later obtained to assess bony healing. The same procedure for diagnosis and conservative treatment was used for each patient. Items that were recorded included the subjects’ age, sport played, mechanism and date of injury, progression of treatment, duration of symptoms, use of bone stimulator, and imaging findings.
Patients diagnosed with lumbar spondylolysis were instructed to cease sport activity and wear a custom thoracolumbosacral (TLSO) orthosis, which was to be worn for 23 hours a day, for a total of 3 months. In addition, an external bone stimulator was prescribed, and patients were instructed to use it daily as much as possible. The brace was removed after three months from time of fracture. After removal of the brace, each patient was prescribed a 6-week physical therapy program with a focus on core strengthening. A follow-up was recommended after the 6 weeks to assess ongoing symptoms and determine if the patient could be granted clearance to gradually return to sport. If symptoms were persistent or severe, rehabilitation was extended, and a facet corticosteroid injection was offered if there was edema in the facets on the initial MRI. Patients with radicular pain were offered an epidural corticosteroid injection if a disc herniation was present on the initial MRI or they were experiencing classic radiculitis symptoms.
The imaging protocol was equivalent for each patient. First, plain radiographs were gathered to determine the presence of spondylolysis. These included anteroposterior and lateral plain radiographs which were acquired on the date of presentation. Sagittal MRI, including STIR sequences, were obtained to confirm the diagnosis. At this time, the intervertebral level and laterality of the fracture was recorded. Severity of spondylolisthesis, if present, was categorized according to magnitude of slippage as per the Meyerding classification. A follow-up CT scan was obtained to assess bony healing 3 months after the date of presentation. In order to minimize radiation, a limited CT sequence, which included axial CT images at the level(s) of fracture and sagittal CT images on each side of the fracture, was obtained. Additional CT scans were obtained in the case of re-injury or return of symptoms.
The hospital's ethics committee reviewed and approved the present study. Informed consent was deemed exempt and was not obtained.
A total of 201 adolescent patients with symptomatic lumbar spondylolysis with a mean age of 14.9 years (SD 1.62) were included in the study. The most common age of injury was 15 years, following a strong normal distribution (Fig. 1). 54.2% of the patients suffered bilateral spondylolysis, and there was no statistically significant difference in laterality for the patients who sustained a unilateral spondylolysis. L5 was the most commonly affected level (74.6%), followed by L4 (21.4 %). No athlete was injured at the L1 level. There were 12 patients with two-level spondylolysis, all of which involved L4 and L5 levels. The demographic and diagnostic characteristics of the spondylolysis study group are summarized in Table 1.
Table 1Patient demographic and injury characteristics
The most common sport played in our patient population was football, comprising nearly half of the study group, which was followed by baseball/softball, cheerleading/gymnastics, basketball, track/cross country, and soccer in descending order. The primary mechanism of injury was weightlifting during a training program closely followed by a football injury. These two combined activities accounted for approximately half of our cases. The first quarter of the calendar year had the highest incidence of injuries with the most injuries occurring in March and the least occurring in December.
One hundred fifty-two out of 201 athletes (75.6%) reported receiving bone stimulators and using them as prescribed. These patients showed a significantly higher rate of bony healing on follow-up CT scans than those who did not use bone stimulators (79.6% vs. 24.4%). However, there was no difference in the rate of return to sports between two groups (Table 2). One hundred ninety-seven athletes reported return to sports or similar level of activities. Forty-seven patients, who did not undergo follow-up CT scans, were not included in assessing bony healing.
Table 2Use of bone stimulator and outcomes, group B = bone stimulator group; group C = control group
Thirty-seven patients (18.4%) received facet or epidural corticosteroid injections due to continued pain after the conservative treatment, and two of them eventually underwent further procedures. One patient proceeded with L4/L5 and L5/S1 rhizotomies, and the other underwent an L4-S1 posterior spinal instrumented fusion. The patient, who required a fusion, has a strong family history of scoliosis and spine pathologies and had developed a grade 4 spondylolisthesis.
Bony healing was observed in 49.8% of patients on follow-up CT scans. Forty-eight athletes (23.9%) also developed spondylolisthesis. Within this sub population of patients, 46 of them were classified as grade 1 spondylolisthesis. The outcomes of the conservative treatment are summarized in Table 3.
The current study demonstrates excellent functional outcomes and return to play in adolescent athletes with spondylolysis when treated with our treatment algorithm, which consists of sports activity cessation, a custom TLSO orthosis, and a bone stimulator for 3 months, followed by a structured physical therapy program.
Clinical outcomes after nonoperative treatment for lumbar spondylolysis in adolescent athletes has been researched using different diagnostic standards, therapeutic interventions, and outcome measures. However, an optimal treatment algorithm is not agreed upon due to limited investigation and heterogeneity of studies reported, making it difficult to compare the efficacy of various conservative treatments. Blanda et al. looked at 82 athletes with spondylolysis treated with activity restriction, bracing, and physical therapy and reported 92% of patients experienced excellent and good functional outcomes [
]. However, 12 out of 82 patients eventually underwent surgical intervention. Similarly, El Rassi et al. and Alvarez-Diaz et al. treated 57 and 34 adolescent soccer players, respectively, with cessation of playing and TLSO [
]. The authors found 93% and 94% of patients returned to playing soccer, respectively.
To our knowledge, this is the largest study to analyze the injury characteristics and outcomes of adolescent athletes who participated in a uniform treatment plan for acute spondylolysis. Following the treatment, 98% of the patients returned to competition, and only one underwent operative management due to unresolved symptoms. This standardized treatment algorithm describes the suitability and duration of conservative modalities as well as diagnostic and follow up imaging protocols with reliable outcomes. Still, it remains unclear whether the use of orthosis or the activity restriction/sport cessation itself contributes more to the improved functional outcomes. El Rassi et al. reported that only 76% of patients demonstrated excellent and good functional outcomes when they did not stop sports, compared to 93% for compliant patients [
]. An additional study looked at 67 patients with spondylolysis treated with a rigid modified Boston brace while allowing for continuation of sports activities. Excellent or good results with no pain and return to full activities were seen in 78% of these patients [
]. The use of external bone stimulator was associated with a higher bony healing rate in our study. The clinical relevance of achieving osseous healing of lumbar spondylolysis is debatable. Many studies including ours demonstrated that bony healing did not correlate with short-term clinical outcome [
]. However, there is no study looked at potential long-term benefits. Theoretically, the bony union of lumbar spondylolysis may prevent isthmic spondylolisthesis and surgical intervention driven by significant slippage.
Injection with steroid and local anesthetics is commonly used for spondylolysis patients who experience refractory back pain after conservative treatment [
]. Kang et al. and Maldague et al. demonstrated that facet joint injection significantly reduced spondylolytic pain in almost half of the patients (48.1% and 45.5%, respectively) at 2 months follow-up [
]. However, the exact mechanism of painful spondylolysis is unclear, and the indication of steroid injection remains controversial. Facet arthrography in patients with lumbar spondylolysis has shown the contrast medium spreading into the adjacent ipsilateral and the contralateral facet joint spaces through pars interarticularis defects [
]. McCormick et al. explained in their cadaveric study that the pars interarticularis is the only barrier between the joint recesses of adjacent ipsilateral joints, and the pars fracture allows communication between the adjacent ipsilateral joints and establishes a communication to the retrodural space [
]. Therefore, the results from facet injection cannot be used to distinguish whether the symptomatic spondylolysis is facetogenic or fracture/lesion related. Kang et al. also reported that there was no significant difference in the response between the patients with facet injection only and the patients with simultaneous facet and epidural injections [
]. In our treatment algorithm, we only recommended epidural injection for patients with radicular pain who had an associated disc herniation present on the initial MRI.
Interestingly, football and baseball/softball were the most commonly played sports by our study population, but more injuries occurred during the first quarter of the calendar year while weight training. We believe that adolescent athletes are more prone to sustaining spondylolysis during off-season conditioning rather than while playing their respective sport. This supports the generally accepted etiology of adolescent spondylolysis as a condition caused by repetitive mechanical stress and micro-trauma rather than a singular traumatic incident.
The age distribution of adolescent athletes with spondylolysis followed a normal distribution centered at 15 years old. The peak height velocity occurs at a mean age of 13.5 years for American children [
]. Hawkins and Metheny have explained the increased incidence of overuse injuries in adolescent athletes after their growth spurt from a biomechanical perspective. First, changes in muscle tissue typically follow changes in limb length and mass. When an adolescent soccer player kicks, for example, the muscles of the lower legs need to produce approximately 30% more force after the growth spurt to generate the same acceleration [
]. Second, the faster-growing bone may increase preload to the muscle-tendon unit. Lastly, the change in material properties of a bone-ligament-bone or muscle-tendon-bone complex occurs after the increase in muscle strength and bone mass [
]. Ligaments and tendons become stiffer and stronger during maturation in response to long-term exercise. As a result, adolescent athletes after peak height velocity have increased susceptibility to certain types of injuries. Furthermore, when these adolescent athletes start high school, they take part in highly regimented sports programs that involve substantial increment in training, which puts them at even higher risk for spondylolysis.
The imaging protocol of this study is a strength. Plain radiographs have limitations in the diagnosis of spondylolysis since pars injuries can be very subtle findings [
]. We accurately identified our study population with increased validity of our data by utilizing an MRI to confirm the diagnosis. CT scans are very useful in assessing for healing, establishing chronic spondylolysis, and to rule out another lesion, such as osteoid osteoma [
]. In this study, limited CT scans allowed us to accurately determine the bony union during the follow-up evaluation. However, the high resolution comes with radiation, and even limited sequence CT scans can be a concern in adolescent patient population. Alternatively, CT scans may be used only on selective patients. For example, in a situation where a rapid return is critical for an athlete with an early pars lesion, a follow-up CT scan may be helpful to assess for bony healing and possible accelerated rehabilitation and return to play [
Our treatment algorithm can be financially costly and might not be suitable for certain patient population. Most of our patients were privately insured. All 201 patients obtained MRIs, 154 of them (76.6%) underwent CT scans, and 152 patients (75.6%) reported receiving bone stimulators. The treatment algorithm can be easily adjusted based on a patient's accessibility. If spondylolysis is diagnosed or suspected on plain radiographs, a patient may be started on the treatment protocol without an MRI and is expected to achieve excellent clinical outcome. The presence of bony healing on CT scans did not affect the succeeding treatment modalities. Therefore, a patient with no follow-up CT scan can still adhere to the treatment algorithm without compromising results. Similarly, our study demonstrated an outstanding short-term outcome with a high rate of return to sports regardless of the use of external bone stimulator, yet further research is needed for its long-term consequences.
This study has certain limitations. First, it is a single-centered retrospective review of 201 patients. This design, however, may also be a strength as all patients were treated with a uniform, easily reproducible treatment algorithm. Secondly, there is no control group to evaluate the effectiveness of the treatment algorithm compared to different modalities. Thirdly, the compliance with using orthosis 23 hours a day and bone stimulator daily was not formally evaluated. Lastly, long-term results of the applied intervention are not reported. Although most patients achieved excellent outcomes after the treatment, the sustainability of function or injury recurrence remains unknown.
This study is relevant for physicians that manage adolescent athletes with lumbar spondylolysis. When treated with our described conservative treatment algorithm, patients achieved excellent results with a high rate of return to sport. A minimum of 3 months of activity restriction and bracing, followed by physical therapy and symptomatic evaluation is recommended for these patients.
Conservative treatment of spondylolysis in adolescent athletes with cessation of sports, thoracolumbosacral orthosis, and bone stimulator followed by rehabilitation was associated with excellent outcomes in terms of return to sports. Level of evidence: Level III
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors .
Declarations of Competing Interests
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
L5 spondylolysis/spondylolisthesis: a comprehensive review with an anatomic focus.