Current Evidence Regarding the Etiology, Prevalence, Natural History, and Prognosis of Pediatric Lumbar Spondylolysis: A Report from the Scoliosis Research Society Evidence-Based Medicine Committee

Effect of lumbar lordosis angle on the development of lumbar spondylolysis in adolescent baseball players: A cross-sectional study

BACKGROUND

Lumbar spondylolysis (LS) is a lumbar vertebral arch stress fracture that often occurs in adolescent athletes, especially baseball players. An increase in lumbar lordosis angle (LLA) increases the compressive stress on the vertebral arch, influencing the development of LS. However, the effect of LLA on LS development in adolescent baseball players is unknown. Therefore, it is necessary to elucidate the risk factors that influence the development of LS. This cross-sectional study aimed investigate the effect of LLA on LS development in adolescent baseball players.

METHODS

Patients were male baseball players aged 11-18 years who visited an orthopedic clinic with a chief complaint of lumbar pain and underwent a magnetic resonance imaging (MRI) examination between January 1, 2018, and October 31, 2021. LLA was defined as the angle formed by the line parallel to the superior endplate of the L1 and S1. A person other than the data analyst measured LLA three times from the MRI, and the average value was used for data analysis. Logistic regression analysis was performed, with the presence or absence of LS as the objective variable and LLA, age, and previous pitching experience as explanatory variables.

RESULTS

Of the 112 subjects included, 79 were in the LS group and 33 in the non-LS group. The LLA was 45.42 ± 8.19° in the LS group and 36.68 ± 8.26° in the non-LS group, with significant differences between the groups. Logistic regression analysis showed that LLA significantly differed with an odds ratio of 1.140 (95% confidence interval: 1.070-1.21), even after adjusting for age and previous pitching experience.

CONCLUSIONS

LLA in adolescent baseball players was significantly greater in the LS group than in the non-LS group, which may influence the development of LS.

Eight-Year Prevalence Trends of Lumbar Spondylolysis and Isthmic Spondylolisthesis in Adolescent Males: A Population-Based Study from a Nationwide Military Draft Medical Examination Database in South Korea

OBJECTIVE

To assess the national and regional trend in the prevalence of lumbar spondylolysis and isthmic spondylolisthesis for adolescent males in South Korea from 2015 to 2022.

METHODS

A total of 2,666,277 Korean adolescent males were routinely examined at regional Military Manpower Administration offices. The data gathered from Military Manpower Administration were retrospectively collected to measure the prevalence and 95% confidence interval of lumbar spondylolysis and isthmic spondylolisthesis according to the year and region in South Korea. The Spearman correlation analysis was performed to assess the correlation between lumbar spondylolysis, isthmic spondylolisthesis, and several factors including height, weight, current smoking rate, and occasional and high-risk alcohol consumption.

RESULTS

The prevalence of spondylolysis per 10,000 individuals showed a gradual increasing trend from 2015 to 2022 On the contrary, the prevalence of isthmic spondylolisthesis per 10,000 individuals decreased over a consecutive 8-year period. There were no statistical differences in the prevalence of spondylolysis and isthmic spondylolisthesis between Greater Seoul and the countryside. The prevalence of isthmic spondylolisthesis was significantly correlated with occasional (r=0.81, P=0.015) and high-risk alcohol consumption (r=0.86, P=0.007).

CONCLUSIONS

The prevalence of lumbar spondylolysis among adolescent men has increased, whereas isthmic spondylolisthesis has shown a decline over a consecutive 8-year period. The trends in prevalence for both lumbar spondylosis and isthmic spondylolisthesis were similar across the regions in South Korea. Notably, there was a significant correlation between the prevalence of isthmic spondylolisthesis and the rate of alcohol consumption in adolescent men.

Factors associated with non-fusion after direct pars repair of lumbar spondylolysis with pedicle screw and lamina hook: a clinical and CT-assessed study

BACKGROUND

Pedicle screw and lamina hook (PSLH) technique is an effective and popular method for direct pars repair of lumbar spondylolysis. There is a lack of studies to explore factors that may influence the healing of spondylolysis after direct pars repair surgery. The present study aimed to investigate the factors associated with non-fusion after direct pars repair of lumbar spondylolysis with PSLH technique.

METHODS

A total of 55 subjects (average age 21.1 ± 6.3 years, a total of 120 pars defects) diagnosed with symptomatic spondylolysis and underwent pars repair surgery with PSLH were followed up and their clinical data were analyzed. Subjects were divided into a non-fusion group and fusion group according to whether the pars defect had bony fusion at last follow-up assessed by CT. Radiographic data, data related to spondylolysis and clinical outcomes were collected and compared between groups.

RESULTS

The mean follow-up time of the 55 patients was 24.8 ± 12.0 (12-64) months. Among the 120 pars defects, 101 defects were successfully fused and 19 were not fused according to CT. The fusion rate was 84.2%. Multivariable logistic regression analysis showed the factors correlated with non-fusion after pars repair surgery: whether the spondylolysis segment was associated with spina bifida occulta (SBO) (P = 0.001), stage of the defect (P = 0.047), width of the defect (P = 0.002), and disc degeneration (P = 0.014).

CONCLUSION

Direct pars repair by PSHL is a reliable treatment for lumbar spondylolysis with a fusion rate of 84.2%. Association with SBO of the spondylolysis segment, a terminal stage of the defect, a wider defect gap, and grade III disc degeneration may be factors associated with non-fusion after direct pars repair of lumbar spondylolysis with PLSH. Non-fusion patients after pars repair appear to have worse clinical results compared to fusion patients.

Management of low back pain accompanying sagittal plane pathologies in children: Spondylolysis/spondylolisthesis and Scheuermann's disease

Background

Low back pain in childhood was underappreciated for a long time, but recent studies report higher prevalences, up to 70%. Two of the common causes are spondylolyis/spondylolisthesis and Scheuermann's disease. These disorders are relevant in a way they both cause significant back pain, and may disrupt the sagittal spinal balance.

Purpose

To present the current evidence on the diagnosis, natural history and treatment of these disorders with a special focus on sagittal spinal alignment.

Methods

This study is conducted as a literature review.

Results and Conclusions

Spondylolysis and low-grade spondylolisthesis have a benign course and are typically treated conservatively. When pars repair is indicated, pedicle screw-based techniques achieve more than 90% fusion with acceptable complication rates. High-grade spondylolisthesis, however, is frequently progressive. Surgical treatment involves fusion, which can be done in situ or after reduction. Reduction is useful for "unbalanced" patients to acquire sagittal spinopelvic balance, and it is important to distinguish these patients. Despite lowering the risk for pseudoarthrosis, reduction brings a risk for neurologic complications. With re-operation rates as high as 40%, these patients definitely require careful preoperative planning. Scheuermann's disease generally causes back pain in addition to cosmetic discomfort during adolescence. If the kyphosis is lower than 60°, symptoms typically resolve into adulthood with conservative measures only. However, it must be kept in mind that these patients may experience problems with physical performance and have a lower quality of life even when the problem seems to have "resolved". Severe kyphosis and intractable back pain are the most frequently referred surgical indications, and surgery typically involves fusion. Proper utilization of osteotomies and proper selection of the upper and lower fusion levels are of utmost importance to prevent complications in these patients.

Comparing the Wiltse approach and classical approach of pedicle screw and hook internal fixation system for direct repair of lumbar spondylolysis in young patients: A case-control study

The aim of this study was to investigate the clinical effect of direct isthmus repair via Wiltse approach and classical approach in the treatment of simple lumbar spondylolysis in young patients. Thirty-three patients with simple lumbar spondylolysis underwent direct isthmic repair via the Wiltse approach (n = 17) or the classical approach (n = 16). The operation time, intraoperative blood loss, postoperative drainage volume, hospital stay, fusion rate, visual analogue scale (VAS), and the Oswestry disability index were evaluated and compared between the 2 groups. The amount of intraoperative blood loss, postoperative drainage volume, and the duration of hospital stay in the Wiltse group were lower than those in the classical group (P < .05). There was no significant difference in Oswestry disability index score between the Wiltse group and the classical group at 3 months, 6 months, and 1 year after operation, but the visual analogue scale score in the Wiltse group was lower than that in the classical group at 6 months after surgery (P < .05). The Wiltse approach was comparable to the classical approach in terms of bone graft fusion time and fusion rate. The Wiltse approach for isthmus repair can achieve the same or even better clinical effect than the classical approach, and the Wiltse approach is more minimally invasive. Pedicle screw-hook internal fixation system combined with autogenous iliac bone graft via Wiltse approach is a feasible, safe, and effective minimally invasive surgical method for the repair of isthmic spondylolysis in young patients.

Isthmic Spondylolisthesis in Young Gymnasts: A Report of Two Cases

Isthmic spondylolisthesis is a condition characterized by the subluxation of one vertebral body over the adjacent inferior vertebral body, secondary to a defect in the pars interarticularis. This paper reports two cases of young acrobatic gymnasts who presented with long-term, progressive lumbosciatic pain and lower limb dysesthesia. One gymnast presented with additional neurogenic bladder dysfunction. Diagnostic testing revealed L5-S1 spondylolisthesis due to bilateral isthmic lysis in both gymnasts. Both underwent L4-S2 fixation followed by L5-S1 transdiscal arthrodesis with Rialto sacroiliac fusion system (Medtronic^®, Minneapolis, MN, USA). Favorable evolution of neuromotor symptoms was observed after rehabilitation, with less residual neurological impairment in the case of higher-grade spondylolisthesis. This case series aims to emphasize the importance of recognizing this pathology in athletes as well as its correct management. Early surgical intervention can prevent the onset and progression of neurological deficits.

Spondylolysis

Spondylolysis is a bony defect of the pars interarticularis and most often results from repetitive stress. Although spondylolysis is usually asymptomatic, symptomatic spondylolysis is the most common cause of identifiable back pain in children and adolescent athletes. A thorough history and physical exam, as well as appropriate imaging studies are helpful in diagnosis. General first-ine therapy for spondylolysis is conservative and consists of rest from sports, core strengthening, as well as spinal bracing. Patients who have failed conservative therapy may consider surgical repair. This article aims to review the epidemiology, pathophysiology, presentation, and treatment options of spondylolysis.

Diagnosis and Management of Spondylolysis and Spondylolisthesis in Children

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Spondylolysis is defined as a defect of the pars interarticularis, and spondylolisthesis is defined as a slippage of a vertebra relative to the immediately caudal vertebra.

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Most cases of spondylolysis and low-grade spondylolisthesis can be treated nonoperatively. Depending on a patient's age, nonoperative treatment may include a thoracolumbosacral orthosis (TLSO), physical therapy, and activity modification. Bracing and physical therapy have been found to be more effective than activity modification alone.

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Patients with dysplastic spondylolisthesis are at higher risk for progression and should be monitored with serial radiographs every 6 to 9 months.

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Operative management is recommended for symptomatic patients with failure of at least 6 months of nonoperative management or patients with high-grade spondylolisthesis.

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Surgical techniques include pars defect repair, reduction, and fusion, which may include posterior-only, anterior-only, or circumferential fusion.

Prevalence of Incidentally Detected Spondylolysis in Children

Purpose

To assess the prevalence of incidentally detected lumbar spondylolysis in children.

Materials and Methods

We retrospectively reviewed the data of 809 patients under the age of 11 years (mean age, 7.0 ± 2.7 years; boys:girls = 479:330) who underwent abdominal and pelvic CT between March 2014 and December 2018. We recorded the presence, level, and laterality (unilateral or bilateral) of spondylolysis. Patients were divided into two groups based on the presence of spondylolysis: the spondylolysis (SP) and non-SP groups.

Results

In total, 21 cases of spondylolysis were detected in 20 patients (20/809, 2.5%). The mean age of the SP group was higher than that of the non-SP group (7.8 ± 1.8 vs. 6.9 ± 2.7 years, p > 0.05). The prevalence of spondylolysis in boys was higher than that in girls (15/479 [3.1%] vs. 5/330 [1.5%], p > 0.05). The prevalence of spondylolysis in school-age children (6–10 year olds) was higher than that in preschool-age children (0–5 year olds) (17/538 [3.2%] vs. 3/271 [1.1%], p > 0.05). L5 was the most common level of spondylolysis (76.2%); one 8-year-old boy had twolevel spondylolysis. One case of isthmic spondylolisthesis was detected in a 10-year-old boy (1/809, 0.1%). There were 11 unilateral spondylolysis cases (11/21, 52.4%).

Conclusion

In our study, the prevalence of spondylolysis in children under the age of 11 was 2.5%. The prevalence was higher in boys than in girls and in school-age than in preschool-age children, despite the lack of any statistically significant differences.

Biomechanical comparison of 3 types of transdiscal fixation implants for fixing high-grade L5/S1 spine spondylolisthesis

BACKGROUND CONTEXT

There are several options for the stabilization of high-grade lumbosacral spondylolisthesis including transdiscal screws, the Bohlman technique (transdiscal fibular strut) and the modified Bohlman technique (transdiscal titanium mesh cage). The choice of an optimum construct remains controversial; therefore, we endeavoured to study and compare the biomechanical performance of these 3 techniques.

PURPOSE

The aim of this study was to compare 3 types of transdiscal fixation biomechanically in an in vitro porcine lumbar-sacral spine model.

STUDY DESIGN/SETTING

Porcine cadaveric biomechanical study.

METHODS

18 complete lumbar-sacral porcine spines were split into 3 repair groups, transdiscal screws (TS), Bohlman technique, and a modified Bohlman technique (MBT). Range of motion (L3 - S1) was measured in an intact and repaired state for flexion, extension, left/right lateral bending, and left/right torsion. To recreate a high-grade lumbosacral spondylolisthesis a bilateral L5/S1 facetectomy, removing the intervertebral disc completely, and the L5 body was displaced 50%-60% over the sacral promontory. Results were analyzed and compared to intact baseline measurements. Standard quasi-static moments (5 Nm) were applied in all modes.

RESULTS

All range of motion (ROM) were in reference to intact baseline values. TS had the lowest ROM in all modes (p=.006-.495). Statistical difference was found only in extension for TS vs. BT (p=.011) and TS vs. MBT (p=.014). No bone or implant failures occurred.

CONCLUSION

TS provided the lowest ROM in all modes of loading compared to Bohlman technique and MBT. Our study indicates that TS results in the most biomechanically stable construct.

CLINICAL SIGNIFICANCE

Knowledge of the biomechanical attributes of various constructs could aid physicians in choosing a surgical construct for their patients.

Lumbosacral Spondylolysis and Spondylolisthesis

Repetitive stress on the lumbosacral spine during sporting activity places the athletic patient at risk of developing symptomatic pars defect. Clinical history, physical examination, and diagnostic imaging are important to distinguish spondylolysis from other causes of lower back pain. Early pars stress reaction can be identified with advanced imaging, before the development of cortical fracture or vertebral slip progression to spondylolisthesis. Conservative management is first-line for low-grade injury with surgical intervention indicated for refractory symptoms, severe spondylolisthesis, or considerable neurologic deficit. Prompt diagnosis and management of spondylolysis leads to good outcomes and return to competition for most athletes.

What is the Optimal Surgical Method for Achieving Correction and Avoiding Neurological Complications in Pediatric High-grade Spondylolisthesis?

BACKGROUND

Controversy persists in the treatment of high-grade spondylolisthesis (HGS). Surgery is recommended in patients with intrusive symptoms and evidence debates the competing strategies. This study compares the radiologic outcomes and postoperative complications at a minimum of 2 years follow-up for patients with HGS treated with instrumented fusion with partial reduction (IFIS) with those treated with reduction, decompression, and instrumented fusion (RIF). We hypothesize that IFIS leads to a lower rate of complication and revision surgery than RIF.

METHODS

A retrospective comparative methodology was used to analyze consecutive HGS treated surgically between 2006 and 2017. Patients diagnosed with ≥grade 3 spondylolisthesis treated with arthrodesis before the age of 18 years with a minimum of 2 years follow-up were included. Patients were excluded if surgery did not aim to achieve arthrodesis or was a revision procedure. Cases were identified through departmental and neurophysiological records.

RESULTS

Thirty patients met the inclusion criteria. Mean follow-up was 4 years. Ten patients underwent IFIS and the remaining 20 underwent RIF. The 2 groups showed no difference in demographics, grade of slip, deformity or presenting symptoms. Of 10 treated with IFIS, the SA reduced by a mean of 10 degrees and C7 sagittal vertical line changed by 31 mm. In the RIF cohort, SA reduced by 16 degrees and C7 sagittal vertical line reduced by 26 mm. PT was unchanged in both groups. In IFIS cohort, 2 patients showed postoperative weakness, resolved by 2 years. None required revision surgery. In the RIF group, 4 sustained dural tears and 1 a laminar fracture, 7 showed postoperative weakness or dysaesthesia, 3 of which had not resolved by 2 years. Eight patients underwent unplanned further surgery, 3 for pseudarthrosis.

CONCLUSIONS

RIF and IFIS show similar radiologic outcomes. RIF shows a higher rate of unplanned return to surgery, pseudarthrosis and persisting neurological changes.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Direct reduction and repair of spondylolysis with grade 1 slip using the smiley face rod: a case report

Objective: Lumbar spondylolysis, caused by stress fracture of the pars interarticularis may lead to a bony defect or spondylolisthesis. In adolescents, its surgical treatment employs the smiley face rod method for direct reduction of pseudoarthrotic spondylolysis and spondylolisthesis. Clinical outcomes of this treatment have been occasionally described; however, implant removal has not been discussed previously. We present a patient with lumbar spondylolysis with grade 1 slip at the 5th lumbar vertebra (L5) per the Meyerding classification.

Patient: A 14-year-old boy presented with chronic severe lower back pain. Since conservative therapy did not resolve pain or enable resuming sports activities, the smiley face rod repair was performed 7 months after the initial treatment.

Result: Anterior slippage of the L5 was surgically reduced. The patient wore a brace for 3 months postoperatively, and partial bone fusion was noted 6 months postoperatively. He resumed his sports activity 8 months postoperatively, and absolute bone fusion was confirmed 18 months postoperatively. Implant removal was performed 3 years postoperatively. Grade 1 slip was corrected with absolute bone fusion, and long-term follow-up revealed good results in terms of healing and rehabilitation.

Conclusion: Smiley face rod method that allows for implant removal after bone fusion is suitable for adolescents.

Characteristics and diagnostic factors associated with fresh lumbar spondylolysis in elementary school-aged children

PURPOSE

We often encounter elementary school-aged children with fresh lumbar spondylolysis and non-union of bone. They may have factors that impede healing, and treatment outcomes need improvement. The purpose of this study was to investigate elementary school-aged patients with fresh lumbar spondylolysis and to identify characteristics that can aid in prompt diagnosis and proper therapy.

METHODS

We retrospectively compared the characteristics of fresh lumbar spondylolysis in elementary school-aged children with those of older patients. We included patients aged 6-18 years with lower back pain and evidence of bone marrow oedema of lumbar pedicles on magnetic resonance imaging (MRI). The elementary school-aged group (group E) included 100 patients aged 6-12 years, and the senior group (group S) included 251 patients aged 13-18 years. We recorded patient sex, duration of lower back pain, injured site (lumbar level, unilateral/bilateral), presence of contralateral pars defect with evidence of high signal change on MRI (short tau inversion recovery), presence of spina bifida occulta (SBO), and follow-up treatment interruption rate.

RESULTS

One-third of the patients in group E were female, and there was an even smaller proportion of females in group S. L5 lumbar spondylolysis was more common in group E. The treatment interruption rate was lower in group E. L5 SBO and contralateral pars defect were more common in group E.

CONCLUSION

L5 lumbar spondylolysis, L5 SBO, and contralateral pars defect were important diagnostic factors in elementary school-aged patients. Identification of these characteristics will aid in prompt diagnosis and proper therapy.

The Joe-Lin Operative Classification System for Pediatric Lumbosacral Spondylolysis and Spondylolisthesis

OBJECTIVE

To propose and validate a novel and comprehensive classification of lumbosacral spondylolysis and spondylolisthesis in the pediatric population according to surgical managements.

METHODS

Cases of pediatric lumbosacral (L5/S1 level) spondylolysis and spondylolisthesis were reviewed. Lumbar Japanese Orthopedics Association score, health-related quality of life, spondylolisthesis, lumbosacral disc degeneration, and dysplastic features were included for evaluation of outcomes after surgery. We also conducted a reliability study to assess the classification.

RESULTS

A classification containing 4 types and a tentative treatment algorithm were proposed: type 1, direct pars repair without segmented fusion, for which the pedicle screw-U rod system is suitable; type 2, simple L5-S1 fusion; type 3, simple L4-S1 fusion; and type 4, simple L5-S2 fusion. All types of spondylolisthesis were suggested to achieve complete reduction and decompression. A total of 162 patients were included and we also reviewed the outcomes of patients in each type. All patients achieved satisfied outcomes. The reliability study showed that the average interobserver agreement was 89.5% (range, 85.2%-92.6%), with κ value of 0.862 (range, 0.802-0.901). Intraobserver agreement ranged from 88.9% to 92.6%, with an average κ value of 0.868 (range, 0.835-0.901).

CONCLUSIONS

In our study, we proposed and validated a novel comprehensive classification of pediatric lumbosacral spondylolysis and spondylolisthesis. The pedicle screw-U rod system provided more benefits in the treatment of simple lumbosacral spondylolysis, and fusion from L5 to S2 combined with S2 screw would also benefit patients with high-degree spondylolisthesis.

Spondylolysis in Young Athletes: An Overview Emphasizing Nonoperative Management

Lumbar spondylolysis is a unilateral or bilateral defect of the pars interarticularis, an isthmus of bone connecting the superior and inferior facet surfaces in the lumbar spine at a given level. Spondylolysis is common in young athletes participating in sports, particularly those requiring repetitive hyperextension movements. The majority of young athletes are able to return to full sport participation following accurate diagnosis and conservative management, including a structured treatment program. Surgical intervention for isolated pars injuries is seldom necessary. A progressive physical therapy (PT) program is an important component of recovery after sustaining an acute pars fracture. However, there is a paucity of literature detailing PT programs specific to spondylolysis. Here, we provide an overview of the epidemiology, natural history, radiographic evaluation, and management of pars fractures in young athletes. In addition, a detailed description of a physiotherapy program for this population that was developed at a spine center within an academic medical center is provided.

Spondylolysis 2019 update

PURPOSE OF REVIEW

Provide a comprehensive overview of lumbar spondylolysis, a frequent cause of lower back pain in children and adolescents, from evaluation to management.

RECENT FINDINGS

With the surge of structured sports participation in the pediatric population, spondylolysis is a common ailment that afflicts many young athletes due to rigorous competition that taxes the growing spine with repetitive extension and rotation.

SUMMARY

Spondylolysis is a fracture through the pars interarticularis. When a child presents with lower back pain, spondylolysis should be at the top of the differential. A thorough history and physical examination are essential. In addition, radiographs of the lumbar spine, anterior posterior and lateral views, MRI and, selectively, computed tomography are useful adjuncts to uncover a pars injury. Timely diagnosis facilitates early treatment which includes rest, optimizing bone health, brace treatment, and physical therapy. If delayed or untreated, spondylolysis may result in nonunion or pars defect. If symptomatic, patients may need surgery to fuse the lumbar facet joints or repair the par interarticularis.

An abundance of developmental anomalies and abnormalities in Pleistocene people

Diverse developmental abnormalities and anomalous features are evident in the Pleistocene Homo fossil record, varying from minor but rare dental, vertebral, and carpal variants to exceptional systemic disorders. There are currently 75 documented anomalies or abnormalities from 66 individuals, spanning the Pleistocene but primarily from the Late Pleistocene Middle and Upper Paleolithic with their more complete skeletal remains. The expected probabilities of finding these variants or developmental disorders vary from <5% to <0.0001%, based on either recent human incidences or relevant Pleistocene sample distributions. Given the modest sample sizes available for the skeletal or dental elements in question, especially if the samples are appropriately limited in time and geography, the cumulative multiplicative probability of finding these developmental changes is vanishingly small. These data raise questions regarding social survival abilities, differing mortuary treatments of the biologically unusual, the role of ubiquitous stress among these Pleistocene foragers, and their levels of consanguinity. No single factor sufficiently accounts for the elevated level of these developmental variants or the low probability of finding them in the available paleontological record.

Current Use of Evidence-Based Medicine in Pediatric Spine Surgery

Evidence-based medicine (EBM) is a process of decision-making aimed at making the best clinical decisions as they relate to patients' health. The current use of EBM in pediatric spine surgery is varied, based mainly on the availability of high-quality data. The use of EBM is limited in idiopathic scoliosis, whereas EBM has been used to investigate the treatment of pediatric spondylolysis. Studies on early onset scoliosis are of low quality, making EBM difficult in this condition. Future focus and commitment to study quality in pediatric spinal surgery will likely increase the role of EBM in these conditions.

Fatigue and damage of porcine pars interarticularis during asymmetric loading

If the articular facets of the vertebra grow in an asymmetric manner, the developed bone geometry causes an asymmetry of loading. When the loading environment is altered by way of increased activity, the likelihood of acquiring a stress fracture may be increased. The combination of geometric asymmetry and increased activity is hypothesised to be the precursor to the stress fracture under investigation in this study, spondylolysis. This vertebral defect is an acquired fracture with 7% prevalence in the paediatric population. This value increases to 21% among athletes who participate in hyperextension sports. Tests were carried out on porcine lumbar vertebrae, on which the effect of facet angle asymmetry was simulated by offsetting the load laterally by 7mm from the mid-point. Strain in the vertebral laminae was recorded using six 3-element stacked rosette strain gauges placed bilaterally. Specimens were loaded cyclically at a rate of 2Hz. Fatigue cycles; strain, creep, secant modulus and hysteresis were measured. The principal conclusions of this paper are that differences in facet angle lead to an asymmetry of loading in the facet joints; this in turn leads to an initial increase in strain on the side with the more coronally orientated facet. The strain amplitude, which is the driving force for crack propagation, is greater on this side at all times up to fracture, the significance of this can be observed in the increased steady state creep rate (p = 0.036) and the increase in yielding and toughening mechanisms taking place, quantified by the force-displacement hysteresis (p = 0.026).

The prevalence of lumbar spondylolysis in young children: a retrospective analysis using CT

PURPOSE

Although lumbar spondylolysis is encountered in general population with an incidence estimated to be 3-10%, limited information is available for children. The aim of the study is to determine the prevalence of spondylolysis according to associated vertebral bony malformation and spinopelvic parameters in children under eight requiring CT evaluation for unrelated lumbar conditions.

METHODS

Seven hundred and seventeen abdominal and pelvic multi-detector CT scans were obtained in patients under 8 years of age were reviewed. Two board certificated radiologists and two resident radiologists retrospectively evaluated CT scans for lumbar spondylolysis and associated malformations. Pelvic incidence and spondylolisthesis were reported.

RESULTS

Our analysis included 717 CT scans in 532 children (259 girls and 273 boys). Twenty-five cases of spondylolysis were diagnosed (16 bilateral and 9 unilateral, 64 and 36%, respectively) in 14 boys (56%) and 11 girls (44%), associating with 12 grade I spondylolisthesis. The mean normal pelvic incidence was 45° (median 44°, SD 7°). The prevalence of spondylolysis was 1% in children under age 3 (n = 3 among 292 patients), 3.7% in children under age 6 (n = 17 among 454 patients) and 4.7% among the 532 patients. Unilateral spondylolysis was significantly associated with a spinal malformation (p = 0.04, Fisher's exact test), with normal pelvic incidence. Half of the patients with bilateral spondylolysis had high pelvic incidence.

CONCLUSIONS

We observed a prevalence peak of unilateral spondylolysis in the context of a specific malformation in young infants under age 4 with normal pelvic incidence, and, then, a progressive increase in the prevalence of bilateral isolated spondylolysis.

Minimally invasive direct pars repair with cannulated screws and recombinant human bone morphogenetic protein: case series and review of the literature

OBJECTIVE

The objective of this study was to describe the use of a minimally invasive surgical treatment of lumbar spondylolysis in athletes by a fluoroscopically guided direct pars screw placement with recombinant human bone morphogenetic protein–2 (rhBMP-2) and to report on clinical and radiographic outcomes.

METHODS

A retrospective review was conducted of all patients treated surgically for lumbar spondylolysis via a minimally invasive direct pars repair with cannulated screws. Demographic information, clinical features of presentation, perioperative and intraoperative radiographic imaging, and postoperative data were collected. A 1-cm midline incision was performed for the placement of bilateral pars screws utilizing biplanar fluoroscopy, followed by placement of a fully threaded 4.0-mm-diameter titanium cannulated screw. A tubular table-mounted retractor was utilized for direct pars fracture visualization and debridement through a separate incision. The now-visualized pars fracture could then be decorticated, with care taken not to damage the titanium screw when using a high-speed drill. Local bone obtained from the curettage was then placed in the defect with 1.05 mg rhBMP-2 divided equally between the bilateral pars defects.

RESULTS

Nine patients were identified (mean age 17.7 ± 3.42 years, range 14–25 years; 6 male and 3 female). All patients had bilateral pars fractures of L-4 (n = 4) or L-5 (n = 5). The mean duration of preoperative symptoms was 17.22 ± 13.2 months (range 9–48 months). The mean operative duration was 189 ± 29 minutes (range 151–228 minutes). The mean intraoperative blood loss was 17.5 ± 10 ml (range 10–30 ml). Radiographic follow-up was available in all cases; the mean length of time from surgery to the most recent imaging study was 30.8 ± 23.3 months (range 3–59 months). The mean hospital length of stay was 1.13 ± 0.35 days (range 1–2 days). There were no intraoperative complications.

CONCLUSIONS

Lumbar spondylolysis treatment with a minimally invasive direct pars repair is a safe and technically feasible option that minimizes muscle and soft-tissue dissection, which may particularly benefit adolescent patients with a desire to return to a high level of physical activity.

Current Evidence Regarding the Surgical and Nonsurgical Treatment of Pediatric Lumbar Spondylolysis: A Report from the Scoliosis Research Society Evidence-Based Medicine Committee

STUDY DESIGN

Structured literature review.

OBJECTIVES

The Scoliosis Research Society requested an assessment of the current state of peer-reviewed evidence regarding pediatric spondylolysis with the goal of identifying both what is really known and what research remains essential to further understanding.

SUMMARY OF BACKGROUND DATA

Spondylolysis is common among children and adolescents and no formal synthesis of the published literature regarding treatment has been previously performed.

METHODS

A comprehensive literature search was performed. The researchers reviewed abstracts and analyzed by committee data from included studies. From 947 initial citations with abstract, 383 articles underwent full text review. The best available evidence for clinical questions regarding surgical and nonsurgical treatment was provided by 58 included studies. None of the studies were graded as level I or level II evidence. Two of the studies were graded as level III evidence. Fifty-six of the studies were graded as level IV evidence. No level V (expert opinion) studies were included in the final list.

RESULTS

Although natural history studies suggest a benign, relatively asymptomatic course for spondylolysis in most patients, both nonsurgical and surgical treatment series suggest that a substantial number of patients present with pain and activity limitations attributed to spondylolysis. Pain resolution and return to activity are common with both nonsurgical and surgical treatment (80% to 85%, respectively). Although it is implied that most surgically treated patients have failed nonsurgical treatment, the specific treatment modalities and duration required before failure is declared are not well defined. There is insufficient evidence to know which patients will benefit from specific treatment modalities (both nonsurgical and surgical).

CONCLUSIONS

Because of the preponderance of uncontrolled case series and the lack of comparative studies, only low-quality evidence is available to guide the treatment of pediatric spondylolysis.