Athletes with unilateral spondylolysis are at risk of stress fracture at the contralateral pedicle and pars interarticularis: a clinical and biomechanical study

The Biomechanics of the Transpedicular Endoscopic Approach

STUDY DESIGN

Biomechanical cadaveric study.

OBJECTIVE

The goal of this study was to analyze the effects of an endoscopic transpedicular approach with different drill diameters (6 and 8 mm) and compare them with the intact native side. In addition, the influence of bone quality on the resistance of the pedicle was investigated.

SUMMARY OF BACKGROUND DATA

Clinical studies have repeatedly highlighted the benefits of endoscopic transpedicular decompression for downmigrated lumbar disc herniations. However, the biomechanical effects on pedicle stability have not been studied up to now.

MATERIALS AND METHODS

Twenty-four vertebras originating from four fresh-frozen cadavers were tested under uniaxial compression load in a ramp-to-failure test: (1) the tunneled pedicle on one side, and (2) the native pedicle on the other side. Twelve lumbar vertebrae were assigned to drill diameter of 6 mm and the other 12 to diameter of 8 mm.

RESULTS

The median ratio of sustained force for the operated side compared with the intact contralateral side is equal to 74% (63-88) for both drill diameters combined. An 8 mm transpedicular approach recorded an axial resistance of 77% (60-88) compared with the intact contralateral side ( P =0.002). A 6 mm approach resulted in an axial resistance of 72% (66-84) compared with the intact opposite side ( P =0.01). No significant difference between the two different drill diameters was recorded ( P =1). For all three subgroups (intact, 8 mm, 6 mm) the Hounsfield units-values and the absolute resistance force showed significant correlations (intact: ρ=0.859; P <0.001; 8 mm: ρ=0.902; P <0.001; 6 mm: ρ=0.835; P <0.001).

CONCLUSION

The transpedicular approach significantly reduces the axial resistance force of the pedicle, which may lead to pedicle fracture. Bone quality correlated positively with the absolute resistance force of the pedicle, whereas the influence of the drill hole diameter plays only a limited role.

Case Report: Lumbar spondylolisthesis with unilateral pedicle cleft and contralateral spondylolysis: a report of two cases and literature review

Background

The causes of pedicle cleft include congenital dysplasia and stress fractures, both of which are rare conditions. Secondary lumbar spondylolisthesis with combined unilateral pedicle cleft and contralateral spondylolysis is extremely rare and can be easily misdiagnosed. We report two cases with these conditions from different causes and discuss the diagnostic and therapeutic features in the context of the literature review.

Case description

Case 1 was a 58-year-old female with a stress fracture change at the left L5 pedicle. Case 2 was a 47-year-old female with a pedicle cleft due to hypoplasia of the left L5 pedicle. Both patients had a combined contralateral spondylolysis and Meyerding grade one lumbar spondylolisthesis, while neither had a clear history of lumbar trauma. After initial conservative treatments failed, both patients underwent a single-segment posterior lumbar interbody fusion with bilateral pedicle screw fixation. Both patients were followed up for more than 1 year postoperatively with clinical symptom relief and bony fusion at the pedicle cleft suggested by a CT scan.

Conclusion

Lumbar spondylolisthesis with unilateral pedicle cleft and contralateral spondylolysis is rarely reported and can be clinically misdiagnosed as simple spondylolisthesis with bilateral spondylolysis. There is no widely accepted surgical option for patients for whom conservative treatment has failed. Our experience suggests that good clinical results may be achieved by single-segment posterior interbody fusion and bilateral pedicle screw fixation. Precise screw placement into the deficient pedicle and sufficient exiting nerve decompression are prerequisites for the success of this surgical option.

Buck technique supplemented by temporary intersegmental pedicle screw fixation to repair lumbar spondylolysis in youth

BACKGROUND

Lumbar spondylolysis is a bone defect in the pars interarticularis of the lumbar vertebral, which is a common cause of low back pain in youth. Although non-surgical treatment is a mainstream option, surgery is necessary for patients with persistent symptoms. Buck technique is widely used as a classical direct repair technique, but it cannot achieve reduction of low-grade spondylolisthesis and reconstruction of lumbosacral sagittal balance. We have described a novel surgical procedure based on Buck technique with temporary intersegmental pedicle screw fixation, and report a series of clinical outcomes in 5 patients to provide a reference for the clinical treatment of young lumbar spondylolysis.

METHODS

Five young patients with symptomatic lumbar spondylolysis with a mean age of 19.20 ± 5.41 years underwent surgical treatment after an average of 7.60 ± 1.52 months of failure to respond to conservative treatment, using a new surgical procedure based on Buck technique combined with temporary intersegmental pedicle screw fixation.

RESULTS

Five patients were successfully operated without serious complications such as nerve and vascular injury. The average operation time was 109.00 ± 7.42 min, the interpretative average blood loss was 148.00 ± 31.14 ml, and the average fusion time was 11.20 ± 1.64 months. All patients were followed up for 2 years after surgery, and the visual analogue score (VAS) of low back pain and Oswestry disability index (ODI) scores were significantly improved compared with those before surgery, and the Henderson's evaluation were rated excellent or good. After the removal of the internal fixation, it was observed that temporary intersegmental fixation could repair the isthmus, reduce lumbar spondylolisthesis, and reconstruct the sagittal balance of the lumbosacral vertebrae while preserving lumbar motion and preventing intervertebral disc degeneration. Postoperative MRI indicated the Pfirrmann classification of the affected discs: 1 case from grade III to grade II, 3 cases from grade II to grade I, and 1 case remained grade II.

CONCLUSIONS

Buck technique supplemented by temporary intersegmental pedicle screw fixation is a highly applicable and effective method for the treatment of adolescent lumbar spondylolysis. The isthmic fusion is accurate, and temporary intersegmental fixation can effectively prevent disc degeneration and reconstruct the sagittal balance of lumbosacral vertebra.

Differences in Lumbopelvic Alignment in Adolescent Male Soccer Players With Bilateral and Unilateral Lumbar Bone Stress Injuries: An MRI Evaluation

Background

Differences in the physical characteristics of bilateral and unilateral lumbar bone stress injuries (BSIs) are unknown.

Purpose

To compare bilateral and unilateral lumbar BSIs in adolescent male soccer players, with a focus on lumbopelvic alignment.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

A total of 78 players (age range, 12-15 years) from a local soccer club who had magnetic resonance imaging (MRI) evaluations were included in the study. Lumbopelvic alignment and lumbar BSI were evaluated using short-tau inversion recovery and 3-dimensional LAVA on 3-T MRI; lumbar BSI was defined as the presence of bone marrow edema and/or the complete and incomplete fracture in the pars region on the MRI. Pelvic tilt (PT) and pelvic outflare angles were assessed on the kicking and pivoting sides, and asymmetry for each parameter was calculated by subtracting the kicking side from the pivoting side. In addition, the lumbar lordosis (LL), sacral slope (SS), and SS relative to LL (calculated by subtracting LL from the SS) were assessed. One-way analysis of variance was performed to compare lumbopelvic alignment in players with bilateral BSI, unilateral BSI, or no abnormal findings (controls).

Results

No significant differences were found regarding lumbopelvic alignment between the players with bilateral versus unilateral lumbar BSI. PT asymmetry was significantly greater in both players with bilateral lumbar BSI and unilateral lumbar BSI compared with controls (P = .018 and P = .016, respectively). In addition, SS relative to LL was significantly greater in players with bilateral lumbar BSI compared with controls (P < .001).

Conclusion

Although there were no significant lumbopelvic alignment differences between bilateral and unilateral BSI, players with bilateral BSI exhibited increased sacral anterior tilt relative to the LL, and the pelvis was more posterior on the pivoting side than on the kicking side in both players with bilateral BSI and unilateral BSI. Our results suggest that lumbopelvic alignment assessment may contribute to the management strategy for players with lumbar BSI and to the identification of players at high risk of lumbar BSI.

Factors associated with return to play following conservative treatment for lumbar spondylolysis among young athletes: A retrospective case series using structural equation modeling

INTRODUCTION

Lumbar spondylolysis is the most common underlying cause of lower back pain (LBP) in young athletes. Conservative treatment methods are often used to reduce pain and promote healing. Several parameters may affect the duration of conservative treatment, such as the time to return to play (RTP), patient behavior, and physical parameters; however, no study has comprehensively assessed the factors that affect the time to RTP.

OBJECTIVES

This study aimed to determine the factors associated with the time required for RTP among young athletes with early-stage spondylolysis receiving conservative treatment using structural equation modeling (SEM).

METHODS

In this retrospective case series, 137 young athletes (128 males and 9 females, aged 9-18 years) with early-stage lumbar spondylolysis were enrolled. All patients were examined using plain radiography and magnetic resonance imaging and treated conservatively (sports cessation, wearing a corset, therapeutic exercises, and low-intensity pulsed ultrasound radiation). SEM was used to investigate the factors affecting the time to RTP in these patients.

RESULTS

The final model included the following factors: spondylolysis laterality, symptom duration, lower-extremity flexibility, treatment interval, patient adherence, and residual LBP. SEM revealed that patient adherence to physician orders (p < 0.01), treatment interval (p < 0.001), and spondylolysis laterality (p < 0.001) contributed directly to shortened RTP.

CONCLUSION

Patient adherence is essential for reducing the time to RTP among young athletes receiving conservative treatment for early-stage spondylolysis.

Minimally invasive treatment of pedicle stress fracture in a young athlete: A case report

INTRODUCTION

Pedicle stress fractures are an uncommon type of non-union often associated with contralateral neural arch interruption in young, active patients. Patients present with long-lasting low back pain, and the diagnosis is usually delayed. Treatment is generally conservative. Few cases treated surgically are described in the literature, with a high degree of treatment heterogeneity and no consensus on optimal treatment.

PRESENTATION OF CASE

A 24-year-old male, following a sports-related trauma, developed persistent lower back pain. Imaging revealed a right L3 pedicle stress fracture with left lamina and pars interarticularis interruption. A minimally invasive percutaneous approach targeting the pedicle fracture was chosen. The procedure aimed to alleviate pain and promote non-union healing, without addressing the contralateral defect. The patient quickly recovered, achieving significant pain relief, and starting a tailored physical therapy program. At the 4-month follow-up, the pedicle fracture healed with callus formation. The patient returned to sports practice.

DISCUSSION

Pedicle stress fractures may result from biomechanical force redistribution. Diagnosis is challenging, necessitating advanced imaging, including bone scintigraphy, MRI, and CT scans. Conservative management with rest, restriction with a brace, and focused rehabilitation usually achieves good results. When conservative management fails, surgery should be considered. Surgical options include direct repair, bone grafting, and screw fixation of the pedicle and contralateral pars defect.

CONCLUSION

Minimally invasive surgery can achieve good clinical and functional results while avoiding blood loss and soft tissue trauma. Treating only the stress fracture is sufficient to promote bone healing, in contrast to more complex procedures.

Biomechanical limitations of partial pediculectomy in endoscopic spine surgery

BACKGROUND CONTEXT

Transforaminal endoscopic decompression is an emerging minimally invasive surgical technique in spine surgery. The biomechanical effects and limitations of resections associated with this technique are scarce.

PURPOSE

The objective of this study was to analyze the effects of three different extents of reduction at the craniomedial pedicle (10%, 25%, and 50%) and to compare them with the intact native side. In addition, the influence of bone quality on the resistance of the pedicle after reduction was investigated.

STUDY DESIGN

Biomechanical cadaveric study.

METHODS

Thirty lumbar vertebrae originating from six fresh frozen cadavers were tested under uniaxial compression load in a ramp-to-failure test: (1) the reduced pedicle on one side, and (2) the native pedicle on the other side. Of the 30 lumbar vertebrae, ten were assigned to each reduction group (10%, 25%, and 50%).

RESULTS

On the intact side, the median axial compression force to failure was 593 N (442.4-785.8). A reduction of the pedicle by 10% of the cross-sectional area resulted in a decrease of the axial load resistance by 4% to 66% compared to the intact opposite side (p=.046). The median compression force to failure was 381.89 N (range: 336-662.1). A reduction by 25% resulted in a decrease of 7% to 71% (p=.001). The median compression force to failure was 333 N (265.1-397.3). A reduction by 50% resulted in a decrease of 39% to 90% (p<.001). The median compression force to failure was 200.9 N (192.3-283.9). At 10% pedicle reduction, the Hounsfield units (HU) value and the absolute force required to generate a pedicle fracture showed significant correlations (ρ=.872; p=.001). At 25%, a positive correlation between the two variables could still be identified (ρ=.603; p=.065). At 50%, no correlation was found (ρ=-.122; p=.738).

CONCLUSION

Resection of the inner, upper part of the pedicle significantly reduces the axial resistance force of the pedicle until a fracture occurs.

CLINICAL SIGNIFICANCE

The extent of pedicle reduction itself plays only a limited role: once the cortical bone in the pedicle region is compromised, significant loss of resistance to loading must be anticipated.

Risk Factors for Symptomatic Bilateral Lumbar Bone Stress Injury in Adolescent Soccer Players: A Prospective Cohort Study

BACKGROUND

Lumbar bone stress injury (BSI) is a high-risk long time-loss injury for adolescent soccer players. However, the risk factors for lumbar BSI are unclear.

PURPOSE

To identify the risk factors for bilateral lumbar BSI for adolescent soccer players.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Adolescent soccer players underwent orthopaedic examination, whole-body dual energy x-ray scan, lumbar magnetic resonance imaging (MRI), and muscle tightness testing at baseline. Lumbar lordosis (LL), sacral slope, maturity stage of lumbar vertebral body, and bone marrow edema (BME) at the L5 were examined via MRI. In addition, bone mineral density and content; trunk lean body mass via dual energy x-ray scan; and bilateral muscle tightness including the iliopsoas, hamstrings, and quadriceps were measured. Lumbar BSI was diagnosed as positive bilateral BME and extension-based lumbar pain. All participants were examined twice, one at 6 months and one at 1 year, after the baseline examination. Multivariate logistic regression analysis was performed to identify the risk factors for bilateral lumbar BSI.

RESULTS

A total of 69 (26.3%) players were diagnosed with bilateral lumbar BSI. Asymptomatic BME (odds ratio [OR], 4.260; 95% CI, 2.153-8.431), apophyseal stage of the lumbar vertebral body (OR, 3.438; 95% CI, 1.698-6.959), sacral slope relative to LL ≥5° (OR, 4.067; 95% CI, 2.021-8.181), and hamstring tightness ≥50° (OR, 3.221; 95% CI, 1.385-7.489) were significantly associated with bilateral lumbar BSI.

CONCLUSION

The incidence of bilateral lumbar BSI was common at 26.2%. Asymptomatic BME, sacral anterior tilt relative to LL, immature lumbar epiphyses, and hamstring tightness were found to be risk factors for bilateral lumbar BSI. The results of this study suggest that regular MRI examination could facilitate the early detection of BME, and improvement in hamstring flexibility and lumbosacral alignment may prevent bilateral lumbar BSI in young athletes.

Biomechanical evaluation of lumbar spondylolysis repair with various fixation options: A finite element analysis

Objective: This study was designed to compare the biomechanical properties of lumbar spondylolysis repairs using different fixation methods by using three-dimensional finite element analysis.

Methods: Five finite element models (A, B, C, D, and E) of L4-S1 vertebral body were reconstructed by CT images of a male patient (A: intact model; B: spondylolysis model; C: spondylolysis model with intrasegmental direct fixation by Buck screw; D: spondylolysis model with intersegmental indirect fixation by pedicle screw system; E: spondylolysis model with hybrid internal fixation). L5-S1 level was defined as the operative level. After the intact model was verified, six physiological motion states were simulated by applying 500 N concentrated force and 10 Nm torque on the upper surface of L4. The biomechanical properties of the three different internal fixation methods were evaluated by comparing the range of motion (ROM), maximum stress, and maximum displacement.

Results: Compared with Model B, the ROM and maximum displacement of Model C, D, and E decreased. The maximum stress on L5/S1 disc in models A, B, and C was much higher than that in Model D and E under extension and lateral bending conditions. Under axial rotation and lateral bending conditions, the maximum stress of interarticular muscle and internal fixation system in Model B and Model C was significantly higher than that in Model D and Model E. In contrast to Model D, the stress in Model E was distributed in two internal fixation systems.

Conclusion: In several mechanical comparisons, hybrid fixation had better biomechanical properties than other fixation methods. The experimental results show that hybrid fixation can stabilize the isthmus and reduce intervertebral disc stress, which making it the preferred treatment for lumbar spondylolysis.

Comparison of alignment and spondylolysis fracture angle in bilateral and unilateral spondylolysis

OBJECTIVES

Spondylolysis occurs bilaterally or unilaterally and bilateral spondylolysis increases the risk of developing isthmic spondylolisthesis. The characteristics of the lumbar lordosis angle (LLA), sacral slope angle (SSA), and spondylolysis fracture angle (SFA) in bilateral spondylolysis compared with those in unilateral spondylolysis have not been clarified. The purpose of this study was to compare the LLA, SSA, and SFA of bilateral and unilateral spondylolysis.

MATERIALS AND METHODS

Thirty-eight patients with lumbar spondylolysis who visited our clinic for an initial visit and 15 age-matched patients with a chief complaint of low back pain were included as controls. Computed tomography films were used to classify all spondylolysis patients into two groups: those with bilateral fractures (bilateral) and those with unilateral fractures (unilateral). The LLA and SSA were measured using lateral X-ray films and the SFA was measured using computed tomography films.

RESULTS

The LLA was significantly higher in all spondylolysis patients than in the control group (p = .026). There was no significant difference in SSA between the spondylolysis and control groups (p = .28). The LLA was significantly higher in the bilateral group than in the unilateral group (p = .018). There was no significant difference in SSA between the bilateral and unilateral groups (p = .15). The SFA was significantly lower in the bilateral group than in the unilateral group (p = .024).

CONCLUSIONS

This study suggests that physical therapy for spondylolysis may be considered bilaterally and unilaterally.

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.

Utility of Physical Examination Findings for Predicting Low-Back Pain in Adolescent Patients with Early-Stage Spondylolysis: A Retrospective Comparative Cohort Study

Introduction

This study aimed to elucidate low-back pain (LBP) characteristics, i.e., its qualities, extent, and location, in patients with early-stage spondylolysis (ESS).

Methods

We recruited patients (≤18 years old) who presented with acute LBP lasting up to 1 month. Patients were divided into ESS and nonspecific LBP (NS-LBP) groups based on their magnetic resonance imaging findings; patients showing no pathological findings that might explain the cause of LBP were classified as NS-LBP. All patients were evaluated using the following tests: hyperextension and hyperflexion (pain provocation tests in a standing position), pain quality (sharp/dull), pain extent (fingertip-sized area/palm-sized area), and pain location (left and/or right pain in side [side]/central pain [center]). We have also compared outcomes between the ESS and NS-LBP groups in terms of gender and physical symptoms.

Results

Of 101 patients, 53 were determined to have ESS (ESS group: mean age: 14.3 years old; 43 males/10 females), whereas 48 had no pathological findings explaining the LBP origin [NS-LBP group (mean age, 14.4 years old; 31 males/17 females)]. Chi-squared test has identified gender (male), a negative result on hyperflexion test, pain extent (fingertip-sized area), and pain location (side) to be significantly associated with ESS. Among these, regression analysis revealed that male gender and LBP located on the side were significantly associated with ESS (p<0.05).

Conclusions

Although the hyperextension test is generally considered useful for ESS, we demonstrated that its association is not deemed significant. Our results indicate that male gender, a negative result of the hyperflexion test, fingertip-sized pain area, and LBP on the side may be specific characteristics of ESS. Of these physical signs, male gender and LBP located on the side are characteristic factors suggesting ESS presence.

The Management of Acute Lumbar Stress Reactions of the Pedicle and Pars in Professional Athletes Playing Collision Sports

Acute stress reactions in the lumbar spine most commonly occur in athletes at the pars interarticularis followed by the pedicle. These reactions occur as a result of repetitive microtrauma from supraphysiological loads applied to the lumbar spine. Characteristic motions such as trunk extension and twisting are also thought to play a role and may be sport-specific. Other risk factors include increased lumbar lordosis, hamstring and thoracolumbar fascia tightness, and abdominal weakness. On physical examination, pain is typically reproduced with lumbar hyperextension. Currently, magnetic resonance imaging or nuclear imaging remain the most sensitive imaging modalities for identifying acute lesions. In the elite athlete, management of these conditions can be challenging, particularly in those playing collision sports such as American football, hockey, or rugby. Nonoperative treatment is the treatment of choice with rehabilitation programs focused on pain-free positioning and progressive strengthening. Operative treatment is rare, but may be warranted for patients symptomatic for >12 months. Specialized diagnosis protocols as well as treatment and return to play guidelines from 4 physicians treating elite athletes playing collision sports are presented and reviewed.

Repair of symptomatic bilateral L5 spondylolysis with autogenous iliac crest graft and temporary intersegmental pedicle screw fixation in youth

Background

When symptomatic spondylolysis fail to respond to nonoperative treatment, surgical management may be required. A number of techniques have been described for repair by intrasegmental fixation with good results; however, there are still some problems. We reported a repair technique with temporary intersegmental pedicle screw fixation and autogenous iliac crest graft. The aim of present study is to assess the clinical outcomes of L5 symptomatic spondylolysis with this technique.

Methods

A retrospective analysis of 128 patients with L5 spondylolysis treated with this method was performed. According to CT scan, the spondylolysis were classified into 3 categories: line, intermediate, and sclerosis type. The diagnostic block test of L5 bilateral pars defect was done in all patients preoperatively. The sagittal and axial CT images were used to determine the bone union. The healing time, complications, number of spina bifida occulta, Japanese Orthopedic Association (JOA) score, and VAS for back pain were recorded. After fixation removal, the rate of ROM preservation at L5S1 was calculated.

Results

There were 97 patients (194 pars) followed with mean follow-up of 23 months (range, 12–36 months). The union rate of pars was 82.0% at 12 months and 94.3% at 24 months postoperatively. Low back pain VAS significantly (P < 0.05) improved from preoperative mean value of 7.2 to 1.3 at the final follow-up postoperatively (P < 0.05). JOA score increased significantly postoperatively (P < 0.05) with average improvement rate of 79.3%. The rates of L5S1 ROM preservation were 79.8% and 64.0% after fixation removal at 1 and 2 years postoperatively. There were 3 patients of delayed incision healing without other complications.

Conclusions

Although sacrificing L5S1 segment motion temporarily, more stability was obtained with intersegmental fixation. This technique is reliable for spondylolysis repair which has satisfactory symptom relief, high healing rate, low incidence of complications, and preserve a large part of ROM for fixed segment.

Features of sacral alar fatigue fractures in adolescent athletes with overuse

Three types of sacral alar fatigue fractures are elderly, postnatal, and sport-related. They are most prevalent in athletes during adulthood; there are few reports of sacral alar fatigue fractures in young athletes. The purpose of this study was to analyze sacral alar fatigue fractures in adolescent athletes. Of the 920 patients hospitalized with low back pain, 13 were diagnosed with sacral alar fatigue fractures with magnetic resonance imaging (MRI) abnormalities. We investigated age, sex, sports discipline, span from symptom onset to consultation, laterality, complication with spondylolysis, computed tomography (CT) findings, and treatment span. The average age was 14.5 years old (8-men and 5-women). The most frequent discipline was basketball. The span to consultation was 13.2 days. The number of right-side cases was 9. Seven cases were complicated by bilateral spondylolysis. MRI abnormalities were observed in all the cases. Only two patients showed abnormal findings on CT. Averagely 67 days after treatment, participants returned to their sports. Sacral alar fatigue fractures suggest that the span from onset to consultation is short. Fracture lines are often unclear on CT, and MRI is useful for diagnosis. More than half of the cases in this study were complicated by lumbar spondylolysis.

Factors associated with failure of bony union after conservative treatment of acute cases of unilateral lumbar spondylolysis

Background

If bone union is expected, conservative treatment is generally selected for lumbar spondylolysis. However, sometimes conservative treatments are unsuccessful. We sought to determine the factors associated with failure of bony union in acute unilateral lumbar spondylolysis with bone marrow edema including contralateral pseudarthrosis.

Methods

This study targeted unilateral lumbar spondylolysis treated conservatively in high school or younger students. Conservative therapy was continued until the bone marrow edema disappeared on MRI and bone union was investigated by CT. We conducted a univariate analysis of sex, age, pathological stage, lesion level complicating the contralateral bone defect, lesion level, and intercurrent spina bifida occulta, and variables with p < 0.1 were considered in a logistic regression analysis. An item with p < 0.05 was defined as a factor associated with failure of bony union.

Results

We found 92 cases of unilateral spondylolysis with bone marrow edema and 66 cases were successfully treated conservatively. Failure of bony union in unilateral lumbar spondylolysis with bone marrow edema was associated with progressive pathological stage (p = 0.004), contralateral pseudarthrosis (p < 0.001), and L5 lesion level (p = 0.002). The odds ratio was 20.0 (95% CI 3.0–193.9) for progressive pathological stage, 78.8 (95% CI 13–846) for contralateral pseudarthrosis, and 175 (95% CI 8.5–8192) for L5 lesion level.

Conclusions

Conservative therapy aiming at bony union is contraindicated in cases of acute unilateral spondylolysis when the pathological stage is progressive, the lesion level is L5, or there is contralateral pseudarthrotic spondylolysis.

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.

Bone Healing in Adolescents with Bilateral L5 Spondylolysis with and without Preexisting Contralateral Terminal Spondylolysis

Study Design

Retrospective cohort study

Purpose

To examine bone healing with conservative treatment in cases of adolescent bilateral L5 spondylolysis.

Overview of Literature

We classified bilateral L5 spondylolysis, which is the most affected spinal level, by fracture stage and aimed to compare the bone healing rate according to the fracture stage and evaluate the presence of a preexisting contralateral terminal fracture at the diagnosis of fresh spondylolysis.

Methods

We evaluated 48 patients (38 boys and 10 girls) with bilateral L5 spondylolysis diagnosed during or before high school. L5 spondylolysis was classified into two groups: fresh group (bilateral fresh spondylolysis cases), and terminal group (cases wherein one side had fresh spondylolysis and the contralateral side had terminal spondylolysis). We investigated the age of examination and bone healing rate in both groups. We investigated progressive-stage lesions and bone healing rate with or without progressive-stage lesions.

Results

The bone healing rate in the fresh group was significantly higher than that in the terminal group 72.0% vs. 26.1%, p=0.003). In both the groups, the bone healing rate was significantly higher in patients without progressive-stage lesions than in those with progressive-stage lesions.

Conclusions

Bone healing of progressive-stage fresh spondylolysis was not achieved by conservative treatment when contralateral terminal spondylolysis was present in adolescents with bilateral L5 spondylolysis. Our results suggest that bilateral L5 spondylolysis treatment strategies must be determined based on the combination of the stages present.

Surgical management of stress fracture of the contralateral pedicle in a baseball player with unilateral lumbar spondylolysis : A case report

We describe successful surgical treatment in a case of L5 unilateral spondylolysis with contralateral pedicle stress fracture that was not resolved by conservative treatment in a high-performing college baseball player. The 20-year-old man presented with left low back pain that stopped his sports activities. Over the previous year, he had experienced a couple of episodes of pain that subsided with cessation of sports but reappeared after a return to sports. Computed tomography and magnetic resonance imaging revealed a right terminal stage pars fracture and a left pedicle stress fracture at L5. The pain originated from the left pedicle fracture, with no pain from the right unilateral spondylolysis. Given that conservative treatment for 1 year had not been effective, we decided on surgical treatment. Bilateral pedicle screws and the smiley face rod method were applied, and both fractures subsequently healed. In the 2 years since the surgery, the patient has returned to sports and has the potential to become a professional player. J. Med. Invest. 67 : 382-385, August, 2020.

Characteristics of adolescent lumbar spondylolysis with acute unilateral fatigue fracture and contralateral pseudoarthrosis

Purpose: This study aimed to examine the characteristics of lumbar spondylolysis with acute lumbar spondylolysis on one side and pseudoarthrotic spondylolysis on the other, relative to acute lumbar spondylolysis on one side only.

Patients and Methods: Short-tau inversion recovery images obtained through magnetic resonance imaging were used to diagnose 58 patients with acute lumbar spondylolysis with bone marrow edema on one side only. A total of 20 patients who had pars defects on the contralateral side (terminal-stage pseudoarthrotic spondylolysis) were included in the contralateral pseudoarthrosis group (P group). The remaining 38 patients with normal images for the contralateral pars interarticularis were included in the unilateral lesion group, in which the contralateral side was normal (U group). We investigated the union rate, age, sex, lesion laterality, vertebral level, pathological stage, and existing spina bifida occulta in both groups.

Results: The P group was characterized by a higher proportion of right-side cases, L5 lesions, more progressed pathological stage, and spina bifida occulta and a significantly lower union rate than the U group.

Conclusion: The union rate in patients with lumbar spondylolysis with acute lumbar spondylolysis on one side and pseudoarthrotic spondylolysis on the opposite side was only 15%. We should inform patients with acute unilateral spondylolysis lesions and contralateral pseudoarthrosis about this poor union rate and urge them to choose their therapy accordingly.

Factors Associated with Ball Velocity and Low Back Pain During Kicking in Adolescent Soccer Players

Purpose

The factors associated with low back pain (LBP) and the relationship between LBP and ball velocity during kicking motion of adolescent soccer players remain largely unknown. This study aims to clarify the relationship between increasing ball velocity and LBP in adolescent soccer players.

Participants and Methods

Adolescent soccer players were divided into two groups according to the presence and absence of LBP (LBP group, n=38 and NBP (no back pain) group, n=29, respectively). Real-time kick motion was measured using a three-dimensional motion analysis system and the angle of the lumbar spine, hip, and center of mass (COM) were calculated. Regression analysis was used to identify factors associated with ball velocity and LBP. In addition, Pearson’s correlation coefficients were determined between the angle of the lumbar spine and hip, and ball velocity and position of COM in the extracted phase from regression analysis.

Results

The major factor associated with increasing ball velocity was the rotation angle of both hips (Adjusted R²=0.244) and vertical position of COM during kicking (Adjusted R²=0.262). Furthermore, the factors associated with LBP were the flexion angle of kick-side hip (OR=1.126) and abduction angle of both hips (kick-side OR=1.124; support-side OR=0.872). The factors for ball velocity and LBP were related to the maximum hip extension phase. In the hip extension phase of kicking, compared with the NBP group, the LBP group showed lesser extension and external rotation of the kick-side hip angle. In the hip flexion phase of kicking, the ball velocity was correlated with vertical (r=0.56)/anterior (r=0.46) position of COM in the NBP group.

Conclusion

To compensate for this restricted hip motion, the LBP group could extend and rotate their lumbar spine, which may likely cause stress to this region.

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Symptomatic Unilateral Pediculolysis Associated with Contralateral Spondylolysis and Spondylolisthesis in Adults-Case Report and Review of Literature

BACKGROUND

The term "pediculolysis" encompasses rare, chronic pedicular changes characterized by pedicle hypertrophy, sclerosis, and pseudoarthrosis, which develop secondary to recurrent microfractures from repeated stress injuries. These stress injuries to pedicles can be insufficiency fractures, commonly reported in elderly patients with associated osteoporosis, or fatigue fractures, which occur in young adolescents involved in heavy sports. These pedicular lesions have been reported in association with defects in other components of the neural arch, including the pars interarticularis and lamina.

CASE DESCRIPTION

We have described a rare case of grade 1 spondylolisthesis with left-sided pediculolysis and contralateral pars lysis in a middle-age female patient without associated osteoporosis or comorbidities. She underwent L5-S1 transforaminal lumbar interbody fusion after initial conservative measures had failed. However, her symptoms persisted even after the surgery and necessitated revision surgery, including left L5 medial pediculectomy, neurolysis of the left L5 nerve root, and extension of instrumentation to L4 bilaterally and L4-L5 posterolateral fusion.

CONCLUSION

We have reported the present case to bring awareness to spine surgeons regarding the existence of this rare entity even in middle-age individuals. From our experience with the present patient, we believe that for patients with L5 pediculolysis and spondylolisthesis, the option of L5 medial pediculectomy and extension of instrumentation to L4 level should be considered.

Stress Injuries of the Spine in Sports

Spine sports stress injuries account for a significant amount of time loss at play in athletes, particularly if left unrecognized and allowed to progress. Spondylolysis makes up most of these stress injuries. This article focuses on spondylolysis, bringing together discussion from the literature on its pathomechanics and the different imaging modalities used in its diagnosis. Radiologists should be aware of the limitations and more importantly the roles of different imaging modalities in guiding and dictating the management of spondylolysis. Other stress-related injuries in the spine are also discussed including but not limited to pedicle fracture and apophyseal ring injury.

The Incidence of Pars Interarticularis Defects in Athletes

STUDY DESIGN

Literature review.

OBJECTIVE

To conduct a literature review of studies reporting the incidence of pars interarticularis defects in athletes of specific sports, in order to allow more targeted prevention and treatment strategies to be implemented for the groups at highest risk.

METHODS

Electronic searches were performed using PubMed, Ovid Medline, EMBASE, Google Scholar, Cochrane Database of Systematic Reviews, and Cochrane Database of Controlled Trials from their dates of inception to September 2017, with the following keywords: "spondylolysis," "sports," "low back pain," and "pars defects."

RESULTS

A total of 509 total articles were retrieved, of which 114 were used in the final review. The incidence of pars interarticularis defects was found to be highest in diving (35.38%), cricket (31.97%), baseball/softball (26.91%), rugby (22.22%), weightlifting (19.49%), sailing (17.18%), table tennis (15.63%), and wrestling (14.74%). Only 5 studies reported the management instituted for their participants, and these were all case reports. Of 74 players with spondylolysis in these studies, 70 (94.59%) underwent conservative treatment and 4 (5.41%) underwent surgical treatment. 61 (82.43%) returned to their previous level of play, 6 (8.11%) retired, and the disposition of the final 7 was not reported.

CONCLUSION

The current medical literature provides good evidence that the incidence of pars interarticularis defects is higher in the athletic population, with the highest incidence in diving. There remains no gold standard protocol for the management of pars interarticularis defects. Further research is required to compare conservative therapy to surgical therapy and to compare the various surgical techniques to each other.

Changes in hip and spine movement with increasing running speed

[Purpose] We aimed to clarify and compare the changes in thoracic and lumbar spine motion and to elucidate the relationship between hip and lumbar spine motion during running. [Participants and Methods] Seven healthy females were recruited in this study. Hip and spine movement were measured using a 3D motion analysis system when running at 6, 9, and 12 km/h. One-way analysis of variance was used to compare the changes in hip joint and spine angles during running. Correlation coefficient analysis was used to determine the relationship between the hip and lumbar spine angles at right and left toe-offs. [Results] As the running speed increased, the rotation angles of the thoracic and lumbar spine and the extension angles of the lumbar spine and hip joint significantly increased in the late stance phase. Significant positive relationships were observed between hip flexion and lumbar spine extension angles at toe-off when running at 6 and 9 km/h but not when running at 12 km/h. [Conclusion] To increase the running speed, participants increased the rotation angle of spine and the extension angles of the hip joint and lumbar spine during the stance phase. Participants extended the lumbar spine to compensate for the restricted hip motion at toe-off, which could cause stress to the lumbar spine.

Low-Intensity Pulsed Ultrasound for Early-Stage Lumbar Spondylolysis in Young Athletes

OBJECTIVE

To examine the effect of low-intensity pulsed ultrasound (LIPUS) on early-stage spondylolysis in young athletes.

DESIGN

Case-control study.

SETTING

A single outpatient orthopedic and sports clinic.

PATIENTS

A total of 82 young athletes (80 boys and 2 girls; mean age, 14.8 years; range, 10-18 years) with early-stage lumbar spondylolysis were enrolled in this study. All patients were examined by plain radiography and magnetic resonance imaging.

INTERVENTIONS

Patients received either standard conservative treatment combined with LIPUS (n = 35) or without LIPUS (n = 47), according to the sequence of admission. The standard conservative treatment included thoracolumbosacral brace, sports modification, and therapeutic exercise.

MAIN OUTCOME MEASURES

The time required to return to previous sports activities was analyzed by using Kaplan-Meier methods with the log-rank test.

RESULTS

The baseline parameters of both groups were not significantly different. The median time to return to previous sports activities was 61 days [95% confidence interval (CI): 58-69 days] in the group treated with LIPUS, which was significantly shorter than that of the group treated without LIPUS (167 days, 95% CI: 135-263 days; P < 0.01).

CONCLUSIONS

These results suggest that LIPUS combined with conservative treatment for early-stage lumbar spondylolysis in young athletes could be a useful therapy for quick return to playing sports.

Dash-Associated Spondylolysis Hypothesis

INTRODUCTION

In past biomechanical studies, repetitive motion of lumbar extension, rotation, or a combination of both, frequently seen in batting or pitching practice in baseball, shooting practice in soccer, and spiking practice in volleyball, have been considered important risk factors of lumbar spondylolysis. However, clinically, these have been identified in many athletes performing on a running track or on the field, which requires none of the practices described above. The purpose of this study was to verify how much impact running has on the pathologic mechanism of lumbar spondylolysis.

METHODS

In study 1, 89 consecutive pediatric patients diagnosed with lumbar spondylolysis at a single outpatient clinic between January 2012 and February 2017 were retrospectively analyzed. In study 2, motion analysis was performed on 17 male volunteers who had played on a soccer team without experiencing low back pain or any type of musculoskeletal injury. A Vicon motion capture system was used to evaluate four movements: maximal effort sprint (Dash), comfortable running (Jog), instep kick (Shoot), and inside kick (Pass).

RESULTS

In study 1, 13 of the 89 patients with lumbar spondylolysis were track and field athletes. In study 2, motion analysis revealed that the hip extension angle, spine rotation angle, and hip flexion moment were similar in Dash and Shoot during the maximum hip extension phase. The pelvic rotation angle was significantly greater in the kicking conditions than in the running conditions.

CONCLUSIONS

Kinematically and kinetically, the spinopelvic angles in Dash were considered similar to those in Shoot. Dash could cause mechanical stress at the pars interarticularis of the lumbar spine, similar to that caused by Shoot, thus leading to spondylolysis.

Two-Level Spontaneous Pedicle Fracture above a Degenerative Spondylolisthesis and Minimally Invasive Treatment

This is a case report and literature review. The objectives of the study are to describe minimally invasive treatment of pedicle fractures, to show contralateral pedicle changes with pedicle fracture treatment, and to review literature on incidence and mechanism of neural arch fractures. After conservative therapy, there are several options for the treatment of pedicle fractures including pediculoplasty, osteosynthesis, or fusion. As patients’ age increases, the incidence of pedicle fracture may rise and minimally invasive pedicle screw treatment represents a good motion-preserving option to stabilize without fusion. We report a patient with spontaneous pedicle fractures above a degenerative spondylolisthesis and evidence of contralateral pedicle changes at L2 and L3. After minimally invasive pedicle screw placement, postoperative imaging demonstrated trabeculation across both L2 and L3 fractures with a resolution of contralateral pedicle sclerotic changes and healing of incompletely fracture contralateral pedicle at L2. Pedicle fractures lead to contralateral pedicle sclerotic changes and potential fracture and may cause significant back pain. Stabilization and healing of the neural arch can be achieved with minimally invasive placement of pedicle screws without need for fusion.

Successful Endoscopic Surgery for L5 Radiculopathy Caused by Far-Lateral Disc Herniation at L5-S1 and L5 Isthmic Grade 2 Spondylolisthesis in a Professional Baseball Player

Background

We report the case of a professional baseball player who had severe leg pain due to lumbar lateral disc herniation at L4-5 and isthmic spondylolisthesis at L5 (double crash syndrome). For early recovery to competitive level, we performed minimally invasive endoscopic decompression surgery without fusion. There are few reports to discuss the usefulness of minimally invasive treatment for top athletes.

Methods

A 29-year-old professional baseball player who played catcher was referred to us with a complaint of right leg pain. The previous doctor diagnosed far-lateral disc herniation and Grade 2 isthmic spondylolisthesis and recommended arthrodesis at L5-S1 as treatment for both pathologies. Radiological imaging showed that the right L5 nerve root was impinged by the 2 lumbar disorders, namely, far-lateral disc herniation and a ragged edge around a pars defect. We had taken into account the patient's occupation and his wish to avoid a lengthy sick leave, and we had performed endoscopic decompression surgery during the offseason. The far-lateral disc herniation at L5-S1 was removed under local anesthesia by percutaneous endoscopic discectomy, after which the ragged edge at the pars defect was removed under general anesthesia using a microendoscopic discectomy system. Given that the patient did not have any low back pain, arthrodesis was not considered.

Results

The leg pain resolved after surgery. The following year (2015), the patient resumed playing baseball from the beginning of the season and played in 41 games. In the 2016 season, he played in 71 games without any symptoms. No further slippage was observed at radiological follow up 1 year after the surgery.

Conclusions

Minimally invasive endoscopic surgery is an option for radiculopathy in very active patients who need an early return to their previous level of physical activity.

Bony Healing of Discontinuous Laminar Stress Fractures Due to Contralateral Pars Defect or Spina Bifida Occulta

Introduction

Although there has been a dramatic improvement in the outcomes of conservative treatment to achieve bony healing due to advances in diagnostic and therapeutic tools, in some patients, the results continue to be unfavorable. The purpose of this study was to investigate the outcomes of conservative treatment in pediatric patients with stress fractures occurring in the lamina that are discontinuous due to a contralateral pars defect or spina bifida occulta (SBO).

Methods

The medical records at our outpatient clinic for 103 consecutive patients (83 boys, 20 girls) with lumbar spondylolysis (LS) were reviewed to identify those who had presented with a stress fracture and a contralateral pars defect or with SBO at the affected lamina level.

Results

Twelve patients (11 boys, 1 girl) of mean age 12.3 (range 8-16) years were identified. Except for 1 stress structure that occurred at L4, all the stress fractures occurred at L5. Six patients had a pars defect, 5 had SBO, and 1 had both. Two of the 6 patients with a contralateral pars defect had early LS, 3 had progressive LS, and 1 had a pedicle fracture. The fracture healed in 1 (50%) of the 2 patients with early LS and in the patient with the pedicle fracture, but did not heal in any of the patients with progressive LS. Two of the 5 patients with SBO at the affected lamina level had early LS and 3 had progressive LS. The bony healing rate was 100% in the 2 patients with early LS and 66.7% in the 3 patients with progressive LS. The fracture healed in the patient with progressive LS and both a pars defect and SBO at the affected lamina.

Conclusions

Contralateral pars defect remains an unfavorable factor for bony healing discontinuous laminar stress fractures.

Predictive Factors for the Outcome of Surgical Treatment of Lumbar Spondylolysis in Young Sporting Individuals

STUDY DESIGN

Retrospective consecutive case series.

OBJECTIVES

Only few sporting individuals with symptomatic lumbar pars injuries require surgical repair and it is often difficult to predict the outcome following surgery. The factors that predict the outcome after direct repair of lumbar pars defect was evaluated clinically and statistically. The preoperative background variables both subjective and objective as well as radiological evaluation were used in a multiple regression model to find the strong predictors of postoperative outcome as measured by VAS (visual analogue scores), ODI (Oswestry Disability Index) and SF-36 (Short Form).

METHODS

Fifty-two consecutive young sporting individuals with a mean age of 19 years (range 8-30 years) were treated surgically for lumbar pars defect confirmed on imaging studies (ie, single-photon emission computed tomography, computed tomography, and magnetic resonance imaging). Fifty patients completed the VAS, ODI, and SF-36 questionnaires as a part of their assessment. Preoperative background variables were used in a multiple regression model to find the strongest predictor of postoperative outcome as measured by ODI. Ethical approval was taken by the institutional review board.

RESULTS

Buck's screw repair of the pars defect was carried out in 44 patients (33 males, 11 female): unilateral in 8 patients (7 males, 1 female) and bilateral in 36 patients (26 males, 10 females). Although age at surgery showed linear colinearity (ρ = 0.32, P < .05), it was not significant in the model. The most consistent association with the preoperative VAS score were the pre- and postoperative ODI scores, that is, ρ = 0.51 (P < .01) and ρ = 0.33 (P < .05), respectively. In the bilateral group, with Buck's repair at a single level, that is, 33 of 36 (93%) patients had returned to sports at a mean time of 7.5 months (range 6-12 months). Overall, 44 of 52 (84%) individuals had returned to their sports with posttreatment ODI score of <10. The stepwise regression modeling suggested 6 independent factors (preoperative ODI, preoperative SF-36 physical component summary (PCS), Buck's repair, multiple operations, professionalism, and pars defect at L3), as the determinants of the outcome (ie, postoperative ODI) in 80.9% patients (R2 = 0.809).

CONCLUSIONS

The outcome after direct repair of pars defect in those younger than 25 years runs a predictable course. Professionalism in sports has a high impact on the outcome. Preoperative ODI and SF-36 PCS scores are significant predictors of good functional outcome. The regression equation can predict the outcome in 80.9% sporting individuals undergoing Buck's repair.

Difference in kick motion of adolescent soccer players in presence and absence of low back pain

Many adolescent soccer players experience low back pain (LBP). However, there are no reports studying the kick motion of adolescent soccer players experiencing LBP. This study aimed to clarify the kick motion of adolescent soccer players in the presence and absence of LBP. We recruited 42 adolescent soccer players and divided them into two groups according to the presence of LBP (LBP group, n=22) and absence of LBP (NBP group, n=20). We measured real-time kick motion using a three-dimensional motion analysis system. We placed 65 spherical markers on each anatomical landmark and calculated the angle of the lumbar spine, center of mass (COM) of the whole body, and displacement of the support foot. We used an unpaired t-test to compare the data between the groups. Compared with the NBP group, the LBP group showed a lateral shift in COM, which increased the duration of kick motion. The presence of LBP affected the posterior positioning of the support foot and restricted the player's lumbar spine from bending laterally. A lateral shift in COM and larger rotation of the lumbar spine could stress the lumbar spine during kick motion. Therefore, coaches and athletic trainers should pay attention to soccer players' lumbar spine rotation and the COM shift during kick motion. This would be important for preventing LBP in adolescent soccer players.

Contralateral Spondylolysis and Fracture of the Lumbar Pedicle in a Young Athlete

STUDY DESIGN

Clinical case report of unilateral pedicular stress fracture with a contralateral spondylolysis in a male high-school athlete presenting with low back pain.

OBJECTIVE

To report this uncommon cause of low back pain in an adolescent athlete, and review the relevant literature.

SUMMARY OF BACKGROUND DATA

The incidence of spondylolysis in the Caucasian population was found to be about 3% to 6%. This number is probably higher in the athletic adolescent age group, with reports ranging from 8% to 15%. Spondylolysis may be associated with pedicle fracture, usually on the contralateral side. This is an uncommon phenomenon that is not well described in the adolescent age group.

METHODS

A 16-year-old male athlete presents with low back pain and limitation in sports as well as in daily activities. Clinical evaluation was suspicious for, and radiographic evaluation revealed left-sided L5 spondylolysis as well as contralateral L5 pedicle fracture. Conservative management included Boston Overlapping brace, external electrical stimulation, modification of activities, and a comprehensive physical therapy program.

RESULTS

Radiological evaluation revealed persistent left L5 pars defect and advanced healing of the contralateral pedicle fracture. The patient achieved complete pain relief and returned to varsity level sporting activity.

CONCLUSION

Complete radiographic and clinical healing of the pedicle defect was observed, with return competitive varsity-level football without symptoms.

LEVEL OF EVIDENCE

5.

Low-intensity pulsed ultrasound is effective for progressive-stage lumbar spondylolysis with MRI high-signal change

PURPOSE

This study aimed to investigate the treatment effects of low-intensity pulsed ultrasound (LIPUS) on progressive-stage spondylolysis. Spondylolysis is a stress fracture of the pars interarticularis. Based on the results of computed tomography, spondylolysis was classified into three categories: early, progressive, and terminal. Bone healing was prolonged or not obtained in progressive-stage spondylolysis. The progression of spondylolysis to nonunion has been associated with an increased incidence of spondylolisthesis. To prevent these clinical conditions, achieving bony healing of the spondylolysis site should be the goal of treatment.

METHODS

15 consecutive pediatric patients with progressive-stage spondylolysis (defects) with MRI high-signal change were analyzed. Nine patients were treated conservative treatment including avoidance of any sport activity and the use of a brace during treatment (conventional). Six patients were treated using LIPUS everyday during treatment in addition to conservative treatment. Approximately every 1.5 months, bone healing was evaluated via CT. Cases that retained defects after 4.5 months were defined as nonunion.

RESULTS

Two patients dropped out during the study period. A total of 13 patients (mean 14.6 ± 2.5 years) from the database met with 19 interarticularis defects. The bone union rate in LIPUS group was significantly higher than that in conventional group (66.7 vs. 10.0%, p = 0.020). The treatment period to bone union was 3.8 months and 2.7 ± 0.3 months in conventional and LIPUS groups.

CONCLUSIONS

This study revealed that LIPUS treatment might be effective for bone union in patients with progressive-stage spondylolysis with MRI high-signal change.

LEVEL OF EVIDENCE

4.

Etiology of Adult-onset Stress Fracture in the Lumbar Spine

STUDY DESIGN

This study was a case series.

OBJECTIVE

The purpose of this paper was to present a case series of fresh stress fractures (spondylolysis) in the lumbar spines of adult athletes.

SUMMARY OF BACKGROUND DATA

Lumbar spondylolysis is a stress fracture of the pars interarticularis, which is generally considered a disease of children or adolescence. There is only 1 case series written in English reporting on adult-onset fresh spondylolysis.

METHODS

Eleven patients aged 20-27 years are included in this case series. A retrospective analysis was made of events that may cause stress fracture such as traumatic episodes or sports activities, spinal level, radiologic findings, stage of spondylolysis, treatment, and prognosis.

RESULTS

Among the 11 patients, two had bilateral early-stage spondylolysis, 7 had unilateral early-stage spondylolysis and 2 had unilateral progressive-stage spondylolysis. Three occurred subsequent to a preexisting terminal-stage spondylolysis in the contralateral side, 1 occurred subsequent to a terminal-stage spondylolysis at the adjacent spinal level, and 1 occurred subsequent to a terminal-stage spondylolysis at a distant level. Thirteen pedicles adjacent to the pars interarticularis in the 11 patients showed bone marrow edema-like signal on magnetic resonance imaging. Six spondylolyses were found at L5, 2 each at L3 and L4, and 1 spondylolysis at L2. The 11 patients were divided into 4 groups according to suspected pathogenic mechanism: preexistent spondylolysis in the contralateral side, alteration of the athletic event, apparent traumatic episode, and others. Conservative treatment was prescribed for return to sports in all cases. Although 1 patient retired because of persistent low back pain, the remaining 10 patients returned to competition.

CONCLUSIONS

Although lumbar spondylolysis is generally recognized to occur in childhood or adolescence, fresh lumbar spondylolysis should be included in the differential diagnosis of adult low back pain when patients are high-level athletes. Conservative treatment should be attempted for adult patients.

Changes in lumbopelvic rhythm during trunk extension in adolescent soccer players

Many adolescent athletes experience low back pain (LBP). Its causative factors include lower limb muscle tightness and hip-spine incoordination. Hip-spine coordination [or lumbopelvic rhythm, LPR] can be used to assess lower-limb and spine functions. We assessed the presence/absence of LBP in adolescent soccer players before and after a six-month period and divided them into four groups: no LBP both before and after the period (NBP group); LBP before but not after (PN group); LBP after but not before (NP group); and LBP both before and after (LBP group). We used a 3D motion analysis system during trunk extension to measure the lumbar spine and hip ranges of motion (ROMs). On comparing the results obtained before and after the six-month period, lumbar spine ROM decreased in the NP group, hip ROM increased in the LBP group. From before to after the period, the linear prediction indicated that, when the hip extends by 1°, the lumbar spine extends by 3.5°-3.2° for the PN group and by 3.4°-2.8° for the NP group. The NP group extended their lumbar spine excessively compared with the hip before the period, which could cause LBP, but decreased the extension after the period. Lumbar extension relative to hip extension decreased in the PN group, which could decrease excessive load on the lumbar spine and eliminate LBP. These findings suggest that to prevent LBP in adolescent soccer players, it is important to restrict lumbar spine extension relative to hip extension.

The effects of muscle weakness on degenerative spondylolisthesis: A finite element study

BACKGROUND

Whether muscle weakness is a cause, or result, of degenerative spondylolisthesis is not currently well understood. Little biomechanical evidence is available to offer an explanation for the mechanism behind exercise therapy. Therefore, the aim of this study is to investigate the effects of back muscle weakness on degenerative spondylolisthesis and to tease out the biomechanical mechanism of exercise therapy.

METHODS

A nonlinear 3-D finite element model of L3-L5 was constructed. Forces representing global back muscles and global abdominal muscles, follower loads and an upper body weight were applied. The force of the global back muscles was reduced to 75%, 50% and 25% to simulate different degrees of back muscle weakness. An additional boundary condition which represented the loads from other muscles after exercise therapy was set up to keep the spine in a neutral standing position. Shear forces, intradiscal pressure, facet joint forces and von Mises equivalent stresses in the annuli were calculated.

FINDINGS

The intervertebral rotations of L3-L4 and L4-L5 were within the range of in vitro experimental data. The calculated intradiscal pressure of L4-L5 for standing was 0.57MPa, which is similar to previous in vivo data. With the back muscles were reduced to 75%, 50% and 25% force, the shear force moved increasingly in a ventral direction. Due to the additional stabilizing force and moment provided by boundary conditions, the shear force varied less than 15%.

INTERPRETATION

Reducing the force of global back muscles might lead to, or aggravate, degenerative spondylolisthesis with forward slipping from biomechanical point of view. Exercise therapy may improve the spinal biomechanical environment. However, the intrinsic correlation between back muscle weakness and degenerative spondylolisthesis needs more clinical in vivo study and biomechanical analysis.

Symptomatic Unilateral Spondylolysis Associated With Nonspondylolytic Lateral Clefts in Adults: Review of an Infrequently Reported Pathology

Nonspondylolytic lateral clefts of the lumbar neural arch (laminolysis and pediculolysis) are rare pathologies that usually occur consequent to repetitive stress injuries in patients with unilateral spondylolysis. These lesions are different from the usual bilateral spondylolytic defects, and their management depends upon the chronicity and the type of bony defect. We hereby discuss the verdict of current literature on underlying pathomechanics and ideal management guidelines of these rare lesions.

Prevalence of Symptomatic Lumbar Spondylolysis in Pediatric Patients

Lumbar spondylolysis, a stress fracture of the pars interarticularis, is prevalent in adolescent athletes. Recent advances in diagnostic tools and techniques enable early diagnosis before these fractures progress to complete fractures through the pars. However, because patients often consult family physicians for primary care of low back pain and these physicians may not have access to diagnostic modalities such as magnetic resonance imaging (MRI) and computed tomography, stress fractures can be missed. This study surveyed the prevalence of symptomatic spondylolysis in pediatric patients who consulted an orthopedic clinic for primary care and investigated whether such acute stress fractures may be overlooked without MRI. The prospective study investigated 264 patients who were younger than 19 years and had low back pain. Of the 153 patients (58.0%) with low back pain persisting for longer than 2 weeks, 136 who agreed to undergo MRI were included in the study. This group included 11 elementary school students, 71 junior high school students, and 54 high school students. The overall prevalence of lumbar spondylolysis was 39.7% (54 of 136) and was 9.3% in elementary school students (5 of 11, 45.5%), 59.3% in junior high school students (32 of 71, 45.1%), and 31.5% in high school students (17 of 54, 31.5%). All 54 patients with spondylolysis had a history of athletic activity. Primary care physicians should recognize that approximately 40% of pediatric patients presenting with low back pain persisting for longer than 2 weeks may have spondylolysis and should consider MRI in those with a history of athletic activity. Because the spine is immature in this age group, almost half of affected elementary school and junior high school students may have lumbar spondylolysis. [Orthopedics. 2016; 39(3):e434-e437.].

State-of-the-art management of low back pain in athletes: Instructional lecture

In this paper, we describe "state of the art" on the diagnosis and treatment for low back pain in athletes. Lumbar motion that induces specific pain would be a clue to the exact diagnosis. In the flexion pain group, lumbar herniated nucleus pulposus is the most common disorder. Discogenic pain and type 1 Modic endplate inflammation may also cause flexion pain; however, the diagnosis is sometimes difficult. In children and adolescents, apophyseal ring fracture is prevalent. In the extension pain group, lumbar spondylolysis is very common, especially in pediatric athletes. In adults, facet pain due to overloading would be the pathology, while low back pain with trunk rotation is not common. However, throwing athletes, such as pitchers and hammer throwers, may experience this kind of pain; facet arthritis contralateral to the throwing arm would be the origin of the pain. Low back pain on lumbar lateral bending is rare, but we experienced some cases in golfers in whom type 1 Modic change at the lateral corner was the source of pain. In this article, we explained strategies for state-of-the-art diagnosis and minimally invasive treatment.

Posterior osteosynthesis of a spontaneous bilateral pedicle fracture of the lumbar spine

Spontaneous bilateral pedicle fractures of the lumbar spine are rare, and an optimal surgical treatment has not been suggested. The authors report the case of a 50-year-old woman who presented with low-back pain and right leg radiating pain of 1 year's duration. Radiological studies revealed a spontaneous bilateral pedicle fracture of L-5. All efforts at conservative treatment failed, and the patient underwent surgery for osteosynthesis of the fractured pedicle using bilateral pedicle screws connected with a bent rod. Her low-back and right leg pain were relieved postoperatively. A CT scan performed 3 months postoperatively revealed the disappearance of the pedicle fracture gap and presence of newly formed bony trabeculation. In rare cases of spontaneous bilateral pedicle fracture of the lumbar spine, osteosynthesis of the fractured pedicle using bilateral pedicle screws and a bent rod is a motion-preserving technique that may be an effective option when conservative management has failed.

Unilateral pedicle stress fracture in a long-term hemodialysis patient with isthmic spondylolisthesis

Most unilateral pedicle stress fractures occur on the contralateral side of patients with unilateral spondylolysis. However, there are few reports of unilateral pedicle stress fractures in patients with bilateral spondylolysis and spondylolisthesis. We report a unique case of unilateral pedicle stress fracture in a long-term hemodialysis patient with isthmic spondylolisthesis. A 65-year-old man who had undergone hemodialysis presented with lower back pain that had persisted for several years. The patient experienced severe right lower extremity pain with no history of trauma. Computed tomography revealed unilateral pedicle fracture with bilateral L5 spondylolysis and spondylolisthesis with progression of scoliosis. The patient underwent Gill laminectomy of L5 with pedicle screw fixation at L4-S1 and interbody fusion at L5-S1. The patient's leg pain ceased immediately, and he began walking without leg pain. In our present patient, development of scoliosis caused by destructive spondyloarthropathy may have contributed to a unilateral pedicle fracture.

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

STUDY DESIGN

Structured literature review.

OBJECTIVES

To assess the current state of evidence as a first step in the development of practice guidelines for pediatric spondylolysis.

SUMMARY OF BACKGROUND DATA

Progress in published medical knowledge, changes in societal expectations, and developments in health care economics have led medical organizations to develop evidence-based documents and products.

METHODS

A comprehensive literature search for pediatric spondylolysis was performed with the assistance of a medical librarian. The authors reviewed citations and abstracts. Abstracts were reviewed for exclusions and data from included studies were analyzed by committee. A total of 44 articles provided the best available evidence for the questions of etiology, prevalence, natural history, and prognosis: 9 were graded as level I evidence, 23 were level II, 3 were level III, and 9 were level IV. No level V studies were included in the final list.

RESULTS

There is good evidence that pediatric lumbar spondylolysis is an acquired fracture of the pars interarticularis that can occur unilaterally or bilaterally. Evidence shows that when chronic, bilateral pars defects develop, 43% to 74% of patients will progress to grade 1 or 2 spondylolisthesis. In addition, unilateral, incomplete, and early lesions can obtain bony union. With or without bony union or spondylolisthesis, short-term symptom resolution is the norm. Long-term prognosis is less clear, but there is fair evidence that most patients will have lumbar symptoms compared with the general population. There is also fair evidence that some patients will develop significant symptoms as adults and will undergo surgical treatment. There is insufficient knowledge to predict which patients will continue to do well in the long term with conservative or no treatment and which patients will develop symptoms significant enough to warrant early intervention.

CONCLUSIONS

The current medical literature provides fair to good evidence for clinically relevant questions regarding the etiology, prevalence, natural history, and prognosis of pediatric spondylolysis.