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Management of lumbar spondylolysis in the adolescent athlete: a review of over 200 cases

Open AccessPublished:April 29, 2022DOI:https://doi.org/10.1016/j.spinee.2022.04.011

      Abstract

      BACKGROUND

      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.

      PURPOSE

      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.

      STUDY DESIGN

      A retrospective review.

      PATIENT SAMPLE

      Two hundred one adolescent patients ranging from age 10 to 19 involved in athletics

      OUTCOME MEASURES

      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.

      METHODS

      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.

      RESULTS

      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.

      CONCLUSIONS

      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.

      Keywords

      Introduction

      Spondylolysis is a defect of the pars interarticularis of vertebrae, most commonly seen at L5 and L4 [
      • Foreman P
      • Griessenauer CJ
      • Watanabe K
      • Conklin M
      • Shoja MM
      • Rozzelle CJ
      • et al.
      L5 spondylolysis/spondylolisthesis: a comprehensive review with an anatomic focus.
      ,
      • Cavalier R
      • Herman MJ
      • Cheung EV
      • Pizzutillo PD
      Spondylolysis and spondylolisthesis in children and adolescents. I: diagnosis, natural history, and nonsurgical management.
      ]. The defect is bilateral in approximately 80% of cases and can occur in more than one level [
      • Gurd DP
      Back pain in the young athlete.
      ]. Spondylolysis diminishes the stability of the spinal motion segment [
      • Floman Y
      Progression of lumbosacral isthmic spondylolisthesis in adults.
      ] 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 [
      • Cassidy RC
      • Shaffer WO
      • Johnson DL
      Spondylolysis and spondylolisthesis in the athlete.
      ,

      AMERICAN ACADEMY OF ORTHOPAEDIC SURGEONS, COMMITTEE ON THE SPINE: A glossary on spinal terminology. Chicago, The American Academy of Orthopaedic Surgeons (no date).

      ]. The incidence of spondylolysis has been reported to be 3% to 11.5% in the general population [
      • Toueg C-W
      • Mac-Thiong J-M
      • Grimard G
      • Parent S
      • Poitras B
      • Labelle H
      Prevalence of spondylolisthesis in a population of gymnasts.
      ,
      • Fredrickson BE
      • Baker D
      • McHolick WJ
      • Yuan HA
      • Lubicky JP
      The natural history of spondylolysis and spondylolisthesis.
      ,
      • Amato ME
      • Totty WG
      • Gilula LA
      Spondylolysis of the lumbar spine: demonstration of defects and laminal fragmentation.
      ,
      • Roche MA
      • Rowe GG
      The incidence of separate neural arch and coincident bone variations: a survey of 4,200 skeletons.
      ,
      • Kalichman L
      • Kim DH
      • Li L
      • Guermazi A
      • Berkin V
      • Hunter DJ
      Spondylolysis and spondylolisthesis: prevalence and association with low back pain in the adult community-based population.
      ] and 23% to 63% in young athletes. [
      • Rossi F
      Spondylolysis, spondylolisthesis and sports.
      ,
      • Foreman P
      • Griessenauer CJ
      • Watanabe K
      • Conklin M
      • Shoja M
      • Rozzelle C
      • et al.
      L5 spondylolysis/spondylolisthesis: a comprehensive review with an anatomic focus.
      ] Spondylolysis frequently develops between 7 and 10 years of age and is very rare in patients under 5 or over 20 years of age [
      • Logroscino G
      • Mazza O
      • Aulisa A
      • Pitta L
      • Pola E
      • Aulisa L
      Spondylolysis and spondylolisthesis in the pediatric and adolescent population.
      ].
      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 [
      • Fredrickson BE
      • Baker D
      • McHolick WJ
      • Yuan HA
      • Lubicky JP
      The natural history of spondylolysis and spondylolisthesis.
      ]. There is some evidence suggesting genetic predisposition as an etiology of spondylolysis. Familial occurrence of lumbar spondylolysis has been established by multiple studies [
      • Kato K
      • Hakozaki M
      • Mashiko R
      • Konno SI
      Familial development of lumbar spondylolysis: a familial case report of 7- and 4-year-old brothers and their father.
      ,
      • Yurube T
      • Kakutani K
      • Okamoto K
      • Manabe M
      • Maeno K
      • Yoshikawa M
      • et al.
      Lumbar spondylolysis: a report of four cases from two generations of a family.
      ,
      • Haukipuro KA
      • Keränen N
      • Koivisto E
      • Lindholm RV
      • Norio R
      • Punto LL
      Familial occurrence of lumbar spondylolysis and spondylolisthesis.
      ]. Also, certain ethic groups, such as Canadian Inuits, have shown a high incidence of spondylolisthesis [
      • Hensinger-Robert N
      Current concepts review. Spondylolysis and spondylolisthesis in children and adolescents.
      ]. A history of trauma is commonly associated with the patients, and some investigators argue that trauma plays a major role in the etiology [
      • Hensinger-Robert N
      Current concepts review. Spondylolysis and spondylolisthesis in children and adolescents.
      ]. However, many vertebral trauma studies have shown that a single traumatic event resulting in an isolated pars interarticularis fracture is extremely rare [
      • Logroscino G
      • Mazza O
      • Aulisa A
      • Pitta L
      • Pola E
      • Aulisa L
      Spondylolysis and spondylolisthesis in the pediatric and adolescent population.
      ]. Nowadays, spondylolysis is generally considered to be a result of repetitive mechanical stress and micro-trauma to a congenitally weak portion of the vertebrae [
      • Wiltse LL
      • Widell EH
      • Jackson DW
      Fatigue fracture: the basic lesion in isthmic spondylolisthesis.
      ,
      • Farfan HF
      • Osteris V
      • Lamy C
      The mechanical etiology of spondylolysis and spondylolisthesis.
      ]. Similarly, the higher incidence of spondylolysis in young athletes is thought to be related to the increased overload in the lumbar spine [
      • Rossi F
      Spondylolysis, spondylolisthesis and sports.
      ,
      • Blanda J
      • Bethem D
      • Moats W
      • Lew M
      Defects of pars interarticularis in athletes: a protocol for nonoperative treatment.
      ].
      Most patients with spondylolysis do not experience pain or other symptoms [
      • Fredrickson BE
      • Baker D
      • McHolick WJ
      • Yuan HA
      • Lubicky JP
      The natural history of spondylolysis and spondylolisthesis.
      ,
      • Logroscino G
      • Mazza O
      • Aulisa A
      • Pitta L
      • Pola E
      • Aulisa L
      Spondylolysis and spondylolisthesis in the pediatric and adolescent population.
      ,] and the role of spondylolysis in producing the low back pain is not yet clear [
      • Libson E
      • Bloom RA
      • Dinari G
      Symptomatic and asymptomatic spondylolysis and spondylolisthesis in young adults.
      ]. Lisbon et al. demonstrated in their study that the patients with unilateral spondylolysis were much less likely to be symptomatic compared to the patients with bilateral defects [
      • Libson E
      • Bloom RA
      • Dinari G
      Symptomatic and asymptomatic spondylolysis and spondylolisthesis in young adults.
      ]. This may suggest that painful spondylolysis is associated with the slippage of the vertebral body. It has been historically estimated that approximately 20% of young patients become symptomatic [
      • Logroscino G
      • Mazza O
      • Aulisa A
      • Pitta L
      • Pola E
      • Aulisa L
      Spondylolysis and spondylolisthesis in the pediatric and adolescent population.
      ], and the onset of symptoms typically coincides intimately with the growth spurt (between age of 10 and 15 years) [
      • Hensinger-Robert N
      Current concepts review. Spondylolysis and spondylolisthesis in children and adolescents.
      ]. Some studies estimate nearly 50% of back pain in adolescent athletes is attributable to spondylolysis [
      • Kalichman L
      • Kim DH
      • Li L
      • Guermazi A
      • Berkin V
      • Hunter DJ
      Spondylolysis and spondylolisthesis: prevalence and association with low back pain in the adult community-based population.
      ,
      • Micheli LJ
      • Wood R
      Back pain in young athletes: significant differences from adults in causes and patterns.
      ]. Symptomatic spondylolysis usually manifests as focal low back pain that worsens with activities, and neurological symptoms are extremely rare [
      • Hambly MF
      • Wiltse LL
      • Peek RD
      • et al.
      Spondylolisthesis.
      ,
      • Shook JE
      Spondylolysis and spondylolisthesis.
      ]. Symptomatic spondylolysis can be successfully treated with noninvasive management that consists of rest, activity restriction, bracing, and physical therapy [
      • Kim HJ
      • Green DW
      Spondylolysis in the adolescent athlete.
      ]. With recent radiological advances and clarification of the pathomechanism of spondylolysis, conservative treatment has shown improved outcomes with high rates of bony healing [
      • Sakai T
      • Tezuka F
      • Yamashita K
      • Takata Y
      • Higashino K
      • Nagamachi A
      • et al.
      Conservative treatment for bony healing in pediatric lumbar spondylolysis.
      ], while surgical treatment of spondylolysis has been reserved for patients who have persistent pain despite conservative treatment [
      • Kim HJ
      • Green DW
      Spondylolysis in the adolescent athlete.
      ,
      • Standaert CJ
      • Herring SA
      Spondylolysis: a critical review.
      ].
      Unfortunately, there is currently a limited consensus on nonoperative treatment modalities and a lack of large scale controlled clinical trials on the diagnosis and management of spondylolysis [
      • Standaert CJ
      • Herring SA
      Spondylolysis: a critical review.
      ]. 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.

      Methods

      Study participants

      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.

      Imaging protocol

      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.

      Results

      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
      ParameterN (%)
      Gender
       Male139 (69.2)
       Female62 (30.8)
      Laterality of spondylolysis
       Left50 (24.9)
       Right38 (18.9)
       Bilateral109 (54.2)
       Unknown4 (2.0)
      Level of spondylolysis
       L10 (0)
       L23 (1.5)
       L312 (6.0)
       L443 (21.4)
       L5150 (74.6)
       L4 and L512 (6.0)
       Unknown5 (2.5)
      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
      ParameterYesNo
      Bony healing on CT
       Group B9023
       Group C1031p-value < .00001
      Return to sports
       Group B1004
       Group C231p-value = .9418
      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.
      Table 3Treatment outcome
      ParameterN
      Intervention37
       Corticosteroid injection37
       Surgery1
      Bony healing on CT100
       Complete94
       Partial6
      Spondylolisthesis48
       Grade 146
       Grade 21
       Grade 30
       Grade 41
      CT, computed tomography.

      Discussion

      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 [
      • Blanda J
      • Bethem D
      • Moats W
      • Lew M
      Defects of pars interarticularis in athletes: a protocol for nonoperative treatment.
      ]. 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 [
      • El Rassi G
      • Takemitsu M
      • Woratanarat P
      • Shah SA
      Lumbar spondylolysis in pediatric and adolescent soccer players.
      ,
      • Alvarez-Díaz P
      • Alentorn-Geli E
      • Steinbacher G
      • Rius M
      • Pellisé F
      • Cugat R
      Conservative treatment of lumbar spondylolysis in young soccer players.
      ]. 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 [
      • El Rassi G
      • Takemitsu M
      • Woratanarat P
      • Shah SA
      Lumbar spondylolysis in pediatric and adolescent soccer players.
      ]. 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 [
      • Steiner ME
      • Micheli LJ
      Treatment of symptomatic spondylolysis and spondylolisthesis with the modified Boston brace.
      ]. 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 [
      • El Rassi G
      • Takemitsu M
      • Glutting J
      • Shah S
      Effect of sports modification on clinical outcome in children and adolescent athletes with symptomatic lumbar spondylolysis.
      ]. 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 WY
      • Lee JW
      • Lee E
      • Kang Y
      • Ahn JM
      • Kang HS
      Efficacy and outcome predictors of fluoroscopy-guided facet joint injection for spondylolysis.
      ]. 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 [
      • Kang WY
      • Lee JW
      • Lee E
      • Kang Y
      • Ahn JM
      • Kang HS
      Efficacy and outcome predictors of fluoroscopy-guided facet joint injection for spondylolysis.
      ,
      • Maldague B
      • Mathurin P
      • Malghem J
      Facet joint arthrography in lumbar spondylolysis.
      ]. 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 [
      • Maldague B
      • Mathurin P
      • Malghem J
      Facet joint arthrography in lumbar spondylolysis.
      ]. 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 [
      • McCormick CC
      • Taylor JR
      • Twomey LT
      Facet joint arthrography in lumbar spondylolysis: anatomic basis for spread of contrast medium.
      ]. 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 [
      • Kang WY
      • Lee JW
      • Lee E
      • Kang Y
      • Ahn JM
      • Kang HS
      Efficacy and outcome predictors of fluoroscopy-guided facet joint injection for spondylolysis.
      ]. 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 [
      • Abbassi V
      Growth and normal puberty.
      ]. 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 [
      • Hawkins D
      • Metheny J
      Overuse injuries in youth sports: biomechanical considerations.
      ]. 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 [
      • Hawkins D
      • Metheny J
      Overuse injuries in youth sports: biomechanical considerations.
      ]. 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 [
      • Kukreja M
      • Hecht AC
      • Tortolani PJ
      Spondylolysis and spondylolisthesis in the adolescent athlete.
      ,
      • Leone A
      • Cianfoni A
      • Cerase A
      • Magarelli N
      • Bonomo L
      Lumbar spondylolysis: a review.
      ]. For example, early stages of pars injuries with stress reactions without complete defects are radiographically occult and can only be properly evaluated on MRIs [
      • Leone A
      • Cianfoni A
      • Cerase A
      • Magarelli N
      • Bonomo L
      Lumbar spondylolysis: a review.
      ]. 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 [
      • Hu S
      • Tribus C
      • Diab M
      • Ghanayem A
      Spondylolisthesis and spondylolysis.
      ,
      • Berger RG
      • Doyle SM
      Spondylolysis 2019 update.
      ]. 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 [
      • Standaert CJ
      Spondylolysis in the adolescent athlete.
      ].
      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.

      Conclusions

      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

      Acknowledgments

      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.

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