What is the Risk of Developing Proximal Junctional Kyphosis During Growth Friendly Treatments for Early-onset Scoliosis?

Maintenance of construct integrity with subaxial cervical pedicle screws when crossing the cervicothoracic junction in complex pediatric deformity: an international multicenter study

OBJECTIVE

In cases of complex pediatric spinal deformity, posterior spinal instrumentation crossing the cervicothoracic junction (CTJ) may be required. This is most frequently encountered for revision surgery to address proximal junctional kyphosis (PJK). In the cervical spine, lateral mass screws are most commonly used, although they may result in biomechanically weak proximal constructs and predispose to instrumentation failure. The use of supplemental anterior constructs has recently been reported with promising results, but this necessitates an additional surgical procedure. Subaxial cervical pedicle screws can provide good biomechanical fixation without the need for an anterior approach, but outcome data have been very limited. The purpose of this study was to assess radiographic and clinical outcomes at two years in pediatric patients who have undergone posterior spinal instrumentation and fusion (PSIF) crossing the CTJ using subaxial cervical spine pedicle screws.

METHODS

The Pediatric Spine Study Group (PSSG) registry was queried to identify patients ≤ 21 years old who underwent PSIF crossing the CTJ with two-year minimum clinical and radiographic follow-up. Patients were excluded if they had a history of anterior stabilization or if their fusion construct with subaxial pedicle screws started below C6. Clinical, surgical, and radiographic parameters were assessed, and measurements were compared statistically.

RESULTS

Then, 8 patients (6 female and 2 male) met inclusion criteria, with a mean age at surgery of 11.2 ± 3.3 years. All patients underwent PSIF crossing the CTJ (mean levels fused 15.6 ± 6.6). The mean density of subaxial cervical pedicle screws was 61.9% ± 27.8 (range 28.5 to 100%). The major coronal curve averaged 54.7° ± 19.6 preoperatively and 34.5° ± 13.6 postoperatively (41.5% ± 26.5 correction; p = 0.03). The average major sagittal curve was 55.9° ± 20.6 preoperatively and 29.6° ± 9.6 (44.2% ± 18.0 correction; p = 0.01) postoperatively. There were no major intraoperative or postoperative complications. Deformity parameters remained stable without radiographic evidence of PJK in 8/8 patients at minimum 2-year follow-up.

CONCLUSIONS

In this small preliminary international series of pediatric patients with spinal deformity, the inclusion of subaxial cervical pedicle screws in constructs that span the cervicothoracic junction resulted in good clinical and radiographic outcomes without major complications. Subaxial cervical spine pedicle screws provide enhanced biomechanical stability and may eliminate the need for additional anterior support in pediatric patients.

Machine learning analysis of cervical balance in early-onset scoliosis post-growing rod surgery: a case-control study

We aimed to analyze the cervical sagittal alignment change following the growing rod treatment in early-onset scoliosis (EOS) and identify the risk factors of sagittal cervical imbalance after growing-rod surgery of machine learning. EOS patients from our centre between 2007 and 2019 were retrospectively reviewed. Radiographic parameters include the cervical lordosis (CL), T1 slope, C2-C7 sagittal vertical axis (C2-7 SVA), primary curve Cobb angle, thoracic kyphosis (TK), C7-S1 sagittal vertical axis (C7-S1 SVA) and proximal junctional angle (PJA) were evaluated preoperatively, postoperatively and at the final follow-up. The parameters were analyzed using a t-test and χ2 test. The machine learning methodology of a sparse additive machine (SAM) was applied to identify the risk factors that caused the cervical imbalance. 138 patients were enrolled in this study (96 male and 42 female). The mean thoracic curve Cobb angle was 67.00 ± 22.74°. The mean age at the first operation was 8.5 ± 2.6yrs. The mean follow-up was 38.48 ± 10.87 months. CL, T1 slope, and C2-7 SVA increased significantly in the final follow-up compared with the pre-operative data. (P < 0.05). The CL and T1 slope increased more significantly in the group of patients who had proximal junctional kyphosis (PJK) compared with the patients without PJK (P < 0.05). The location of the upper instrumented vertebrae (UIV) and single/dual growing rod had no significant influence on the sagittal cervical parameters (P > 0.05). According to the SAM analysis of machine learning algorithms, Postoperative PJK, more improvement of kyphosis, and T1 slope angle were identified as the risk factors of cervical sagittal imbalance during the treatment of growing rod surgery. The growing rod surgery in EOS significantly affected the cervical sagittal alignment. Postoperative PJK and more improvement of kyphosis and T1 slope angle would lead to a higher incidence of cervical sagittal imbalance.

Proximal foundation anchor variations and their correlation with unplanned return to the operating room (UPROR) in children with EOS treated with magnetically controlled growing rods (MCGR)

INTRODUCTION

The evolution of MCGR technique has led to modifications in the configuration of the proximal construct to decrease the incidence of implant-related complications (IRC) and revision surgeries. However, there is no data characterizing the performance of the most used configurations reducing the risk of complications.

METHODS

487 patients were identified from an international multicenter EOS database.

INCLUSION CRITERIA

EOS patients, primary dual MCGR, complete radiographs, and minimum of 2-year follow-up. 76 patients had incomplete X-rays, 5 had apical fusions, and 18 had inconclusive complications, leaving 388 patients for review. A digital spine template was created to document UIV; number of levels; number, type, and location of anchors; as well as implant configuration. First available postoperative and latest follow-up radiographs were reviewed by two senior surgeons and two spine fellows. UPROR due to IRC was defined as any change in proximal anchors between the postoperative and final follow-up radiographs.

RESULTS

The most common proximal construct configuration: UIV at T2 (50.0%) with 17.5% UPROR, followed by T3 (34.0%) with 12.1% UPROR; number of levels was three (57.1%) with 16.8% UPROR and two (26.0%) with 17.0% UPROR; number of proximal anchors was six (49.9%) with 14.1% UPROR and four (27.0%) with 18.3% UPROR. The most common anchors were all screws (42.0%) with 9.9% UPROR, and all hooks (26.4%) with 31.4% UPROR (P < 0.001). The construct with the lowest rate of UPROR was a UIV at T2, with six anchors (all screws) across three levels (42 cases), with 0% UPROR. Other construct combinations that yielded 0% UPROR rates were UIV of T3, six anchors (all screws) across three levels (25 cases), and a UIV of T3 with six anchors (screws and hooks) across three3 levels (9 cases).

CONCLUSION

Proximal anchor configuration impacts the incidence of UPROR due to IRC in MCGR. UIV at T2 and T3 compared to T4, and the use of all screws or combination of screws and hooks compared to all hooks were associated with a lower UPROR rate. The most common construct configuration was T2 UIV, three levels, six anchors, and all screws. The use of a combination of six anchors (screws or screws and hooks) across three levels with a UIV at T2 or T3 was associated with a lower UPROR rate. Additional research is needed to further evaluate the variables contributing to configuration selection and their association with IRC.

Diagnostic and therapeutic strategies in early onset scoliosis: A current concept review

Substantial advances in the treatment of early onset scoliosis (EOS) over the past two to three decades have resulted in significant improvements in health-related quality of life of affected children. In addition to classifications that address the marked heterogeneity of this patient population, increasing understanding of the natural history of the disease, and new implants and treatment techniques have resulted in innovations unlike any other area of pediatric orthopedics. The growing understanding of the interaction between spinal and thoracic growth, as well as dependent lung maturation, has had a lasting impact on the treatment strategy of this potentially life-threatening disease. The previous treatment approach with early corrective fusion gave way to a growth-friendly concept. Despite the steady development of new growth-friendly surgical treatment options, whose efficacy still needs to be validated, as well as a revival of conservative growth control with serial casts and/or braces, the psychosocial burden of the long lasting and complication-prone treatments remains high. As a consequence, EOS still represents one of the greatest pediatric orthopedic challenges.

Changes in sagittal balance and pre-existing junctional angle influence development of proximal junctional kyphosis in growth guidance systems for early-onset scoliosis

PURPOSE

Proximal junctional kyphosis (PJK) has been reported to occur at a rate of about 30% in traditional growing rods (GR) and magnetically controlled growing rods (MCGR). Growth guidance systems (GGS) have non-rigid, gliding fixation along rods, which may mitigate PJK. There have been no studies done in shilla around PJK, hence this study aimed to assess the occurrence, risk factors, and timeline of PJK.

METHODS

A prospective, multicenter database was queried for EOS patients who underwent surgery utilizing GGS.

INCLUSION CRITERIA

< 10 years at index surgery and > 2 year follow-up.

RESULTS

Sixty-five patients (thirty-six female) met inclusion criteria. Mean age at index surgery was 6.2 y/o (2-9); mean follow-up was 66 m. Most common etiologies were syndromic (n = 23). Mean thoracic kyphosis at pre-op was 41.8°, post-op was 35.5°, and final was 42.2°. Mean PJA at pre-op was 6.15°, post-op 1 was 4.2°, and final was 15.6°. Incidence of PJK at post-op was 35% and final was 43%. Pre-op sagittal balance and change in sagittal balance from pre-op to post-op were associated with post-op PJK (p = 0.05, 0.02). Change in spinal height from pre-op to post-op was associated with PJK at final (p = 0.04). Interestingly, increased PJA at pre-op was significantly associated with decreased PJK at post-op and final (p = 0.01, 0.03).

CONCLUSION

PJK was identified in 43% of patients post-operatively after GGS for EOS. Pre-op PJA was negatively correlated with an increased incidence of PJK. Changes in sagittal balance, in either direction, was the strongest predictor for development of PJK post-operatively.

Implant-Related Complications Do Not Interfere with Corrections with the Shilla Technique in Early Onset Scoliosis: Preliminary Results

Growth-preservation techniques are utilized in early onset scoliosis (EOS) cases requiring surgical intervention. The Shilla technique corrects the deformity by reducing additional surgeries with its growth-guidance effect. As with other techniques, various problems can be encountered following the administration of the Shilla technique. The aim of this study was to examine the effect of complications encountered with the Shilla treatment on correction and growth. Sixteen patients with a follow-up period of at least one year after receiving Shilla growth guidance for EOS were included in this retrospective study. No complications occurred, and no unplanned surgery was required in 50% of the cases. Of the remaining eight patients with postoperative implant-related complications (50%), six (37.5%) required unplanned surgery; this consequently caused implant failure in the proximal region in five cases (31.25%) and deep tissue infection around the implant in one case (6.25%). Deformity correction, spine length, and quality-of-life scores significantly improved in EOS through Shilla growth guidance. In terms of spinal growth and deformity correction, there were no significant differences between patients with implant-related problems and individuals without occurrences. Although implant-related problems were detected in our dataset and corresponding unexpected surgeries were necessary, these complications had no significant unfavorable influence on correction and spine growth.

Low radius of curvature growth-friendly rib-based implants increase the risk of developing clinically significant proximal junctional kyphosis

BACKGROUND

Clinically significant proximal junctional kyphosis (PJK) occurs in 20% of children with scoliosis treated with posterior distraction-based growth-friendly surgery. In an effort to identify modifiable risk factors, it has been theorized biomechanically that low radius of curvature (ROC) implants (i.e., more curved rods) may increase post-operative thoracic kyphosis, and thus may pose a higher risk of developing PJK. We sought to test the hypothesis that early onset scoliosis (EOS) patients treated with low ROC distraction-based implants will have a greater risk of developing clinically significant PJK as compared to those treated with high ROC (straighter) implants.

METHODS

We conducted a retrospective review of prospectively collected data obtained from a multi-centre EOS database on children treated with rib-based distraction with a minimum 2-year follow-up. Variables of interest included: implant ROC at index (220 mm or 500 mm), participant age, pre-operative scoliosis, pre-operative kyphosis, and scoliosis etiology. PJK was defined as clinically significant if revision surgery with a superior extension of the upper instrumented vertebrae was performed.

RESULTS

In 148 participants with scoliosis, there was a higher risk of clinically significant PJK with low ROC (more curved) rods (OR: 2.6 (95% CI 1.09-5.99), χ² (1, n = 148) = 4.8, p = 0.03). Participants had a mean pre-operative age of 5.3 years (4.6y 220 mm vs 6.2y 500 mm, p = 0.002). A logistic regression model was created with age as a confounding variable, but it was determined to be not significant (p = 0.6). Scoliosis etiologies included 52 neuromuscular, 52 congenital, 27 idiopathic, 17 syndromic with no significant differences in PJK risk between etiologies (p = 0.07). Overall, participants had pre-op scoliosis of 69° (67° 220 mm vs 72° 500 mm, p = 0.2), and kyphosis of 48° (45° 220 mm vs 51° 500 mm, p = 0.1). The change in thoracic kyphosis pre-operatively to final follow-up (mean 4.0 ± 0.2 years) was higher in participants treated with 220 mm implants compared to 500 mm implants (220 mm: 7.5 ± 2.6° vs 500 mm: - 4.0 ± 3.0°, p = 0.004).

CONCLUSIONS

Use of low ROC (more curved) posterior distraction implants is associated with a significantly greater increase in thoracic kyphosis which likely led to a higher risk of developing clinically significant PJK in participants with EOS.

LEVEL OF EVIDENCE

Level III - retrospective comparative study.

Complications of single growing rod constructs in the treatment of severe early-onset scoliosis: a lesson relearned

PURPOSE

Early-onset scoliosis (EOS) is one of the most challenging areas of orthopedic management. Previous studies have reported that EOS patients were associated with high risk of complications following growth-friendly surgery. This study was performed to evaluate the complications of single traditional growing rods (TGRs) in the treatment of EOS.

METHODS

In a retrospective chart review study, medical records of all EOS patients treated with single TGRs between 2006 and 2018 were analyzed. Patients under the age of 10 at the time of surgery who had at least 24 months of follow-up were included. Intra- and post-operative complications included both device-related and disease-related complications. Statistical analysis was performed with SPSS.

RESULTS

A total of 35 patients with a mean age of 5.7 ± 2.1 years with the mean follow-up duration of 33.3 ± 9.1 months were included in the final analysis. Of the 35 participants, 27 children (77.1%) experienced at least one complication. A total of 61 complications were observed, giving rise to 1.7 complications per patient. An unplanned surgical procedure was needed to manage 42 of the 61 complications (68.8%). Thirty-five cases of implant failure, 11 cases of deep infection, and 2 cases of junctional kyphosis were identified.

CONCLUSION

It seems that even in the setting that the use of dual TGRs is not possible, the use of single TGRs as the only therapeutic modality should be minimized due to high rate of complications even as a bridge treatment.

LEVEL OF EVIDENCE

Therapeutic level III.

Risk factors for proximal junctional kyphosis after pediatric spinal deformity surgery with halo gravity traction

PURPOSE

To determine risk factors for proximal junctional kyphosis (PJK) in pediatric patients with scoliosis undergoing halo gravity traction (HGT) prior to posterior spinal fusion (PSF).

METHODS

Data from consecutive patients who underwent PSF after HGT with 2-year follow-up were retrospectively collected from a single center. Patients were divided into two groups: PJK vs. no PJK.

RESULTS

Twenty-five patients (age 13.6 ± 3.1 years) underwent HGT for a mean of 42 ± 37 days. Eight patients (32%) developed radiographic PJK and 1 (4%) developed proximal junctional failure. PJK patients had greater loss of cervical lordosis (-17.4 ± 23.2 vs. 2.7 ± 16.2°, p < 0.05), greater increase in lumbar lordosis (9.3 ± 19.5 vs. -2.8 ± 12.8°; p = 0.034) during traction, and smaller overall major coronal curve angle correction (-16.8 ± 30.6 vs. -36.6 ± 16.4°; p = 0.026). From postoperative to last follow-up, PJK patients had a greater increase in upper end vertebrae (UEV) slope (3.3 ± 7.8 vs. -4.0 ± 7.7°; p = 0.004). Selection of UIV based on which vertebra was most level either pre-traction or in-traction was not associated with PJK development (p > 0.05).

CONCLUSION

In-traction radiographic changes of decreased cervical lordosis, decreased major coronal curve, increased lumbar lordosis, and disruption of cervical sagittal balance at last follow-up may have implications for level selection and risk of PJK.

Scoliosis flexibility correlates with post-operative outcomes following growth friendly surgery

PURPOSE

The purpose of this study was to determine the relationship between pre-operative scoliosis flexibility and post-operative outcomes, including curve correction and complications, for patients who have been treated with growth friendly surgery (GFS) for early onset scoliosis (EOS).

METHODS

The study was conducted as a retrospective review of prospectively collected data from an international, multicenter, EOS database. EOS patients with pre-operative flexibility radiographs (traction or bending) were identified. Pre-operative flexibility and immediate post-operative correction were calculated for each patient. Post-operative complications were recorded at final follow-up. Pearson correlations were determined for flexibility vs correction for all patients and were compared between etiologies and between device types (MCGR, TGR, VEPTR).

RESULTS

107 patients (14 congenital, 43 neuromuscular, 31 syndromic, 19 idiopathic) with mean age 7.1 years at index surgery were identified. Mean pre-operative scoliosis was 77°. Mean flexibility of 36% was not significantly different between etiologies. Mean immediate post-operative scoliosis was 46° (p < 0.001 vs. pre-operative) with mean correction of 38%. Correction rate was not significantly different between etiologies; however, correction rate was different between device types (MCGR 45%, TGR 40%, VEPTR 14%; p =  < 0.001). Pearson correlation for flexibility vs correction was fair (r = 0.37, p < 0.001). This correlation was observed for idiopathic (r = 0.53, p = 0.020) and neuromuscular (r = 0.46, p = 0.0020) scoliosis, but not for congenital or syndromic scoliosis. At a mean of 6.1 year follow-up (minimum 2 years to 15.5 years), 60 of 81patients (74%) experienced at least one complication. Odds ratio for developing a complication was 3.00 (1.03-8.76) for patients with pre-operative flexibility < 45% (p < 0.05).

CONCLUSIONS

As lower pre-operative flexibility was associated with less scoliosis correction and with a higher risk of post-operative complications, curve flexibility should be considered when deciding upon the timing of growth friendly surgery.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Unmatched rod contouring at the proximal end predisposes to occurrence of junctional kyphosis in early-onset scoliosis patients undergoing traditional growing rods treatment

STUDY DESIGN

A retrospective case series.

OBJECTIVE

To investigate whether unmatched rod contouring at the proximal end predisposed to the occurrence of proximal junctional kyphosis (PJK) in early-onset scoliosis (EOS) patients after traditional growing rods (TGR) treatment. TGR treatment has become a mainstay of treatment for EOS patients. PJK is one of the most common alignment-related complications.

METHODS

A consecutive series of EOS patients who had undergone TGR treatment were retrospectively reviewed. They were divided into PJK and non-PJK groups according to the occurrence of PJK or not. Demographic data, surgical strategies, and radiographic parameters were recorded and compared between groups. Proximal junctional angle (PJA) was defined as the angle between the caudal endplate of the UIV and the cephalad endplate of the second supradjacent vertebra above the UIV, while proximal rod contouring angle (PRCA) was defined as the angle of proximal rod contouring, which was represented by the angle between the cephalad endplate of the UIV and the caudal endplate of the second vertebra caudal to the UIV. Unmatched proximal rod contouring was regarded if the postoperative PRCA-PJA difference was greater than 5°.

RESULTS

This study finally included 73 patients. The mean age at the index surgery was 6.5 ± 2.2 years (range, 2-10 years). Mean follow-up lasted 5.0 ± 1.7 years (range, 2-9 years). They received mean 4.6 ± 1.6 lengthening procedures. There were 13 patients who were observed with PJK (18%). In comparison with the non-PJK group, the PJK group showed a larger preoperative major curve (82 ± 21° vs 70 ± 17°, P = 0.041) and global kyphosis (57 ± 6° vs. 44 ± 15°, P = 0.044). In addition, the PJK group had significantly larger postoperative PJA (10 ± 3 vs. 5 ± 3, P<0.001) and greater postoperative PJA-PRCA (6 ± 3 vs. 3 ± 3, P = 0.031). The proportion of patients with unmatched proximal rod contouring in PJK group was significantly higher than that in the non-PJK group (69% vs. 25%). Multiple logistic regression showed that preoperative GK>50°, postoperative PJA>10 and postoperative unmatched proximal rod contouring were the risk factors in predicting PJK after TGR treatment.

CONCLUSION

Approximately 18% EOS patients experienced PJK after TGR treatment. Unmatched proximal rod contouring may be an independent risk factor of PJK occurrence, in addition to greater preoperative GK and larger postoperative PJA.

LEVEL OF EVIDENCE: 3

Relook into the Risk Factors of Proximal Junctional Kyphosis in Early Onset Scoliosis Patients: Does the Location of Upper Instrumented Vertebra in Relation to the Sagittal Apex Matter?

OBJECTIVE

Growing rods surgery is the mainstay of treatment for early-onset scoliosis (EOS) while proximal junctional kyphosis (PJK) is one of the most commonly reported postoperative complications. We sought to investigate the impact of the location of upper instrumented vertebra (UIV) in relation to the sagittal apex on proximal junctional kyphosis in EOS after traditional growing rods (GRs) treatment.

METHODS

A total of 102 EOS patients who received traditional growing rods treatment with a follow-up of at least 2 years between 2009 and 2020 were retrospectively reviewed. Radiographic measurements were performed before and after the index surgery and at the latest follow-up. We investigated the coronal Cobb angle and spinopelvic parameters of the whole spine. The location of the UIV, apex, lower instrumented vertebra (LIV), inflection vertebra (IV), the number and distance of UIV-apex, LIV-apex and IV-apex were also recorded. Risk factors for PJK were analyzed by logistic regression analysis.

RESULTS

PJK was observed in 21 patients (20.6%) during the follow-up period. The PJK group showed a younger age at the index surgery (5.9 vs. 7.1 years, P = 0.042), more lengthening procedure times (5.0 vs. 4.0, P = 0.032), larger preoperative coronal Cobb angle (82.0 vs. 75.6°, P = 0.038), higher correction rate (51.2% vs. 44.4%, P = 0.047) and larger postoperative proximal junctional angle (PJA) (13.9 vs. 5.5°, P < 0.001) than the non-PJK group. The ratio of the number and distance from UIV-apex to IV-apex also differed significantly between the two groups. The logistic regression revealed that age at the index surgery ≤ 7 years, the ratio of the number from UIV- apex to IV- apex ≤ 0.6 and the ratio of the distance from UIV- apex to IV- apex ≤ 0.6 were independent risk factors for postoperative PJK.

CONCLUSION

Besides younger age, a closer location of UIV relative to the sagittal apex is identified to be an independent risk factor of postoperative PJK. Selection of UIV at a relatively farther location away from the sagittal apex might help prevent occurrence of PJK.

Proximal junctional kyphosis in pediatric spinal deformity surgery: a systematic review and critical analysis

PURPOSE

Proximal junctional kyphosis (PJK) is a commonly encountered clinical and radiographic phenomenon after pediatric and adolescent spinal deformity surgery that may lead to post-operative deformity, pain, and dissatisfaction. Understanding the risk factors of PJK can be useful for pre-operative informed consent as well as to identify any potential preventative strategies.

METHODS

We performed a systematic review and critical analysis following the PRISMA statement in July 2019 by searching the PubMed, Scopus, and Embase databases, including all prior published studies. We included articles with data on PJK in patients with operative pediatric and adolescent scoliosis and those that detailed risk factors and/or preventative strategies for PJK. Levels of evidence were determined based on consensus. Findings were summarized and grades of recommendation were assigned by consensus. This study was registered in the PROSPERO database; 202,457.

RESULTS

Six hundred and thirty five studies were identified. Thirty-seven studies met criteria for inclusion into the analysis. No studies including neuromuscular scoliosis met inclusion criteria. No findings had Grade A evidence. There were 4 findings found to contribute to PJK with Grade B evidence in EOS: higher number of distractions, disruption of posterior elements, greater sagittal plane correction. There was no difference in incidence noted between etiology of the curvature. Five findings with Grade B evidence were found to contribute to PJK in AIS populations: higher pre-operative thoracic kyphosis, higher pre-operative lumbar lordosis, longer fusion constructs, greater sagittal plane correction, and posterior versus anterior fusion constructs.

CONCLUSION

Greater sagittal plane correction has Grade B evidence as a risk factor for PJK in both EOS and AIS populations. In EOS patients, an increased number of distractions and posterior element disruption are Grade B risk factors. In AIS patients, longer fusion constructs, higher pre-operative thoracic kyphosis and lumbar lordosis, and posterior (as opposed to anterior) constructs also contributed to PJK with Grade B evidence. These findings can guide informed consent and surgical management, and provide the foundation for future studies.

Effects of Growing Rod Technique with Different Surgical Modes and Growth Phases on the Treatment Outcome of Early Onset Scoliosis: A 3-D Finite Element Analysis

Early onset scoliosis (EOS) is emerging as a serious threat to children’s health and is the third largest threat to their health after myopia and obesity. At present, the growing rod technique (GRT), which allows patients to regain a well-balanced sagittal profile, is commonly considered as an invasive surgical procedure for the treatment of EOS. However, the risk of postoperative complications and instrumentation breakage remains high, which is mainly related to the choice of fixed mode. Several authors have studied primary stability and instrumentation loads, neglecting the mechanical transmission of the spinal long-segment model in different growth phases, which is fundamental to building a complete biomechanical environment. The present study aimed to investigate the kinematic and biomechanical properties that occur after GRT, across the long spinal structure and the posterior instrumentation, which are affected by unilateral or bilateral fixation. Accordingly, spinal segments (C6-S1) were loaded under flexion (Flex), extension (Ext), left lateral bending (LB), right lateral bending (RB), left torsion (LT), and right torsion (RT) using 11 established spinal models, which were from three growth phases. The stress distribution, spinal and intervertebral range of motion (ROM), counter torque of the vertebra, and bracing force on the rods were measured. The results showed that bilateral posterior fixation (BPF) is more stable than unilateral posterior fixation (UPF), at the expense of more compensations for the superior adjacent segment (SAS), especially when the superior fixed segment is closer to the head. Additionally, the bracing force of the instrumentation on the spine increases as the Cobb angle decreases. Accordingly, this biomechanical analysis provides theoretical suggestions for the selection of BPF or UPF and fixed segments in different growing phases.

Prevalence of junctional kyphosis in early-onset scoliosis: can it be corrected at final fusion?

PURPOSE

To investigate the risk and predictive factors of junctional issues after conversion from Traditional growing rod (TGR) to definitive spinal fusion in Early-onset scoliosis (EOS).

METHODS

Retrospective review of a multicenter EOS database. TGR patients who received final fusion with at least two-year follow-up were included. Proximal (PJA) and Distal junctional angles (DJA) on pre-final fusion, post-final fusion (within one year of surgery), and at latest follow-up were measured on lateral upright spinal radiographs. Differences in values among designated time points and predictive factors of junctional issues were evaluated statistically.

RESULTS

Forty-six of 251 patients (28 females, 18 males and mean age at final fusion: 12 ± 2 [9-17] years) met the inclusion criteria. Mean follow-up between first postoperative measurement and latest follow-up was 49 ± 22 (24-112) months. No statistical differences in PJA and DJA values were available at pre-fusion, first post-fusion, or latest follow-up (p = 0.827, p = 0.076). Fifty percent of patients had extension of TGR instrumentation at fusion, either proximal or distal. No factor including sex and etiology, lumbar lordosis, thoracic kyphosis, major curve magnitude, PJA, and DJA at pre-fusion was found to be a predictive issue for extension of index TGR instrumentation, except the history of at least one implant-related complication during the period from index surgery to the definitive fusion.

CONCLUSION

PJA and DJA remained stable when transitioning from TGR to final posterior spinal fusion. But 50% of patients had extension of construction at fusion, either proximal or distal.

Crossing the cervicothoracic junction in complex pediatric deformity using anterior cervical discectomy and fusion: a case series

PURPOSE

Proximal instrumentation failure is a challenge in posterior spinal fusions (PSFs) crossing the cervicothoracic junction. High rates of proximal junctional kyphosis (PJK) and loss of fixation have been reported. In this single-center retrospective cohort study, we evaluate the utility of anterior cervical discectomy and fusion (ACDF) in addition to traditional PSF crossing the cervicothoracic junction in order to mitigate implant-related complications.

METHODS

All patients who underwent PSF across the cervicothoracic junction with ACDF with 2 years of follow-up data were reviewed. We analyzed clinical, surgical, and radiographic measures such as operative details, presence of PJK, complications, instrumentation migration, curve angles, and vertebral translation. Measurements were compared statistically using paired samples t-tests.

RESULTS

Ten patients (6 girls, 4 boys) met inclusion criteria with a mean age at surgery of 12.8 ± 3.3 years and follow-up of 3.38 ± 0.9 years. All patients underwent ACDF (range 1-3 levels), and 8 (80%) underwent traction. The average number of levels fused posteriorly was 16.7 ± 4.7 and anteriorly was 2.4 ± 0.7. The major coronal curve averaged 48.8 ± 34.7° preoperatively and 23.3±13.3° postoperatively (p = 0.028). The average major sagittal curve was 83.5 ± 24.2° preoperatively, resolving to 53.9 ± 25.5° (p=0.001). One patient suffered rod breakage at T7, and another developed symptomatic PJK 19 months postoperatively.

CONCLUSION

Our data suggest that ACDF procedures added to PSFs crossing the cervicothoracic junction offer promise for reducing risk for instrumentation-related complications. ACDF also significantly helps improve and maintain both coronal and sagittal correction over 2 years.

LEVEL OF EVIDENCE

4.

Complications of dual growing rod with all-pedicle screw instrumentation in the treatment of early-onset scoliosis

BACKGROUND

Treatment of early-onset scoliosis (EOS) is still a challenge to patients, families, and surgeons. Previous studies have indicated that EOS patients are at high risk for complications following growth-friendly surgery. This study was performed to evaluate the results and complications of all-pedicle screw dual growing rod instrumentation in the treatment of EOS.

METHODS

In an IRB-approved retrospective study, we searched the electronic medical records of our institution for all patients who underwent posterior spinal instrumentation for scoliosis between March 2014 and March 2017. Patients under the age of 10 at the time of surgery who were treated with a growth-friendly technique were then selected. Patients with incomplete records and less than 2 years of follow-up were excluded. Charts, operative notes, clinic visits, and radiographs were extracted. Radiographs were reviewed, and the main curve Cobb angle, thoracic kyphosis, pelvic tilt, pelvic incidence, sacral slope, and proximal junctional angles were measured. We specifically looked for any intra-operative or post-operative complications. Statistical analysis was performed to determine the risk factors of complications.

RESULTS

A total of 42 patients with a mean age of 4.8 ± 2.1 years (range, 1.5-8 years) were included in the final analysis. Patients were followed for a median of 34 months (range, 24-55). The major curve was corrected from a mean of 42.9° ± 10.7° to 28.8° ± 9.6° at the latest follow-up. Proximal junctional angles and thoracic kyphosis increased significantly during the follow-up period (both P values < 0.001). A total of 7 complications (17%) were observed. Four patients (10%) developed superficial surgical site infections, all of which resolved with antibiotics and one round of surgical debridement. Three cases (7%) of proximal junctional kyphosis (PJK) were encountered during the study period, none of which required revision surgery. Pre-operative thoracic kyphosis was the only significant risk factor for the development of PJK.

CONCLUSIONS

Our findings suggest that in settings without access to magnetically controlled growing rods, dual growing rods with all-pedicle screw instrumentation is still a viable treatment strategy with comparable results and complications. The most common complications are infection and PJK, with the latter being associated with a larger pre-operative thoracic kyphosis.

Sagittal spinopelvic changes after posterior spinal fusion in adolescent idiopathic scoliosis

PURPOSE

This article examines if longer posterior spinal fusions with instrumentation (PSFI) into the lumbar spine (L3/4) alter spinopelvic parameters compared with selective fusions to T12/L1/L2 in adolescent idiopathic scoliosis (AIS) patients.

METHODS

We analysed radiographs of 84 AIS patients, 58 (69%) females and 26 (31%) males, who underwent PSFI at an mean age of 15 years ± 2.5 years, range 10 years to 21 years, between 1st January 2007 and 31st December 2014. Radiographic parameters were measured pre- and post-operatively at most recent follow-up (range 2 years to 8.2 years): pelvic incidence (PI), lumbar lordosis (LL, L1-S1 and L4-S1), sagittal vertical alignment (SVA), scoliosis angle and proximal junctional kyphosis (PJK). PI-LL was calculated. Data was analysed using t-tests or Wilcoxon rank-sum tests.

RESULTS

In total, 32 patients underwent a selective fusion with lowest instrumented vertebra (LIV) T12-L2, and 52 patients underwent a fusion with LIV L3-L4. In both groups, scoliosis angle was significantly corrected at follow-up (p < 0.005).Pre-operatively, both groups had similar LL (L1-S1) and PI-LL. Post-operatively, LL increased in the L3-4 fusion group (p < 0.005) but did not change in the selective fusion group (p = 0.116). This change in LL in the L3-4 fusion group affected the post-operative PI-LL (T12-L2 fusion -4.9° versus L3-4 fusion -13.6°, p = 0.002). No differences were seen in PI, SVA or LL L4-S1 between groups. Radiographic PJK occurred in seven of the L3-4 patients with and without PJK (noPJK -8.8° versus PJK -25.8°, p = 0.026).

CONCLUSIONS

In patients who underwent a fusion ending at L3 or L4, LL was increased. This altered the PI-LL relationship, and appeared to increase the risk of PJK.

LEVEL OF EVIDENCE

III.

Five or more proximal anchors and including upper end vertebra protects against reoperation in distraction-based growing rods

STUDY DESIGN

Retrospective multi-center enrollment.

OBJECTIVE

To examine the impact of patient and surgical factors on proximal complication and revision rates of early onset scoliosis patients using a multicenter database. Proximal anchor pullout and junctional kyphosis are common causes necessitating revision surgery during growth friendly treatment of early onset scoliosis (EOS). Many options exist for proximal fixation and may impact the rate of these complications.

METHODS

Retrospective review of multicenter database of patients with growth friendly constructs for EOS. Inclusion criteria were patients with index instrumentation < 10 years of age and minimum of 2 year follow-up.

RESULTS

353 patients met the inclusion criteria and had the following constructs: growing rods with spine anchors = 303; growing rods with rib anchors = 15 and VEPTR = 35. Mean age at index instrumentation was 6.0 years. Mean preoperative Cobb angle was 76° and mean kyphosis was 54°. Mean follow-up was 6.0 years. 21.8% of patients (77/353) experienced anchor pullout. Lower anchor pullout rates were associated with a higher numbers of proximal anchors (p = 0.003, r = - 0.157), and 5 or more anchors were associated with lower rates of anchor pullout (p = 0.014). Anchor type (rib hooks vs spine anchors vs rib cradle) did not impact rate of anchor pullout (p = 0.853). Kyphosis data was available for 198 patients. 23.2% (46/198) of these patients required proximal extension of their construct after index surgery. Initial instrumentation below the upper end vertebrae (UEV) of kyphosis was associated with higher rates of subsequent proximal revision; 28.9% (20/69) compared to 20.1% (26/129) for those instrumented at or above the UEV (p = 0.035). Preoperative kyphosis and change in thoracic kyphosis were not associated with anchor pullout (p = 0.436, p = 0.115) or proximal revision rates (p = 0.486, p = 0.401).

CONCLUSION

Five or more anchors are associated with lower rates of anchor pullout. Proximal anchor placement at or above the UEV resulted in a significant decrease in rates of proximal extension of the construct.

PREVALENCE OF PJK AFTER ARTHRODESIS IN PATIENTS WITH NEUROMUSCULAR SCOLIOSIS IN THE SECOND POSTOPERATIVE YEAR

ABSTRACT Objective The primary objective of this study was to analyze the prevalence of PJK in patients with neuromuscular scoliosis submitted to posterior spinal arthrodesis with instrumentation. Proximal junctional kyphosis (PJK) is a frequent phenomenon that, due to its importance, began to be studied by several authors, who laid the foundations for the radiographic definition and possible risk factors for its occurrence after long spinal arthrodesis with instrumentation. Despite the large number of PJK studies, most were related to the occurrence of adolescent idiopathic scoliosis, adult deformity and early-onset scoliosis, with few being targeted to patients with congenital and neuromuscular scoliosis. Methods In this study, data from electronic medical records of patients with neuromuscular scoliosis who underwent posterior arthrodesis with instrumentation between the years 2014 and 2016 were analyzed. Information on age, gender, pathology and radiographic measurements were extracted from this sample at the 2nd and 24th postoperative months. Results A total of 39 patients with neuromuscular scoliosis were analyzed. The sample was predominantly male (58.87%) and the mean age was 14.05 years. PJK occurred in 18 patients during the two years following surgery, with a prevalence of 46.15%. The incidence of PJK in the 2nd and 24th postoperative months was 23.1% and 30%, respectively. Conclusions A prevalence of PJK of 46.15% was found in patients with neuromuscular scoliosis treated surgically with posterior instrumentation after two years of follow-up, as compared to previous results . Level of Evidence III; Cross-sectional observational study.

The Effect of Spinopelvic Parameters on the Development of Proximal Junctional Kyphosis in Early Onset: Mean 4.5-Year Follow-up

BACKGROUND

Proximal junctional kyphosis (PJK) is a major complication after posterior spinal surgery. It is diagnosed radiographically based on a proximal junctional angle (PJA) and clinically when proximal extension is required. We hypothesized that abnormal spinopelvic alignment will increase the risk of PJK in children with early-onset scoliosis (EOS).

METHODS

A retrospective study of 135 children with EOS from 2 registries, who were treated with distraction-based implants. Etiologies included 54 congenital, 10 neuromuscular, 37 syndromic, 32 idiopathic, and 2 unknown. A total of 89 rib-based and 46 spine-based surgeries were performed at a mean age of 5.3±2.83 years. On sagittal radiographs, spinopelvic parameters were measured preoperatively and at last follow-up: scoliosis angle (Cobb method, CA), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope and PJA. Radiographic PJK was defined as PJA≥10 degrees and PJA≥10 degrees greater than preoperative measurement. The requirement for the proximal extension of the upper instrumented vertebrae was considered a proximal junctional failure (PJF). Analysis of risk factors for the development of PJK and PJF was performed.

RESULTS

At final follow-up (mean: 4.5±2.6 y), CA decreased (P<0.005), LL (P=0.029), and PI (P<0.005) increased, whereas PI-LL (pelvic incidence minus lumbar lordosis) did not change (P=0.706). Overall, 38% of children developed radiographic PJK and 18% developed PJF. Preoperative TK>50 degrees was a risk factor for the development of radiographic PJK (relative risk: 1.67, P=0.04). Children with high postoperative CA [hazard ratio (HR): 1.03, P=0.015], postoperative PT≥30 degrees (HR: 2.77, P=0.043), PI-LL>20 degrees (HR: 2.92, P=0.034), as well as greater preoperative to postoperative changes in PT (HR: 1.05, P=0.004), PI (HR: 1.06, P=0.0004) and PI-LL (HR: 1.03, P=0.013) were more likely to develop PJF. Children with rib-based constructs were less likely to develop radiographic PJK compared with children with spine-based distraction constructs (31% vs. 54%, respectively, P=0.038).

CONCLUSIONS

In EOS patients undergoing growth-friendly surgery for EOS, preoperative TK>50 degrees was associated with increased risk for radiographic PJK. Postoperative PI-LL>20 degrees, PT≥30 degrees, and overcorrection of PT and PI-LL increased risk for PJF. Rib-based distraction construct decreased the risk for radiographic PJK in contrast with the spine-based constructs.

LEVEL OF EVIDENCE

Level III.

Unplanned return to operation room (OR) following growing spinal constructs (GSCs) in early onset scoliosis (EOS)-a multi-centric study

PURPOSE

To evaluate the incidence and risk factors associated with the unplanned return to OR in EOS.

METHODS

Medical records of 51 patients of EOS operated at three different centres using various types of GSCs were evaluated for complications requiring unplanned surgeries. Data were analysed to find out rate of unplanned surgeries in relation to the aetiology, age and Cobb angle at index surgery, type of implant, cause of unplanned surgery, and management required.

RESULTS

Out of 51 patients, three did not meet inclusion criteria. Forty-eight patients of EOS operated by GSCs with a mean age of 6.7 years (range 2-12 years) with an average follow-up of 67.3 months were studied. There were 30 congenital, 10 idiopathic, 4 syndromic, and 4 neuromuscular cases. Thirty-nine out of 48 patients had one or more unplanned surgeries on follow-up (81.25%). Out of total 248 surgeries following index procedure, 82 were unplanned surgeries (33.06%), including 53 implant revisions, 12 implant-removal, 14 debridement, and 2 flaps. The common complications were 24.14% rod/screw breakage, 42.53% anchor pull-out, 16.09% infections, 6.90% wound dehiscence, and 4.6% neuro deficits. Unplanned surgeries were significantly higher in syndromic (58.8%) and neuromuscular (52.9%) than congenital (27.2%) and idiopathic (37.8%) cases (p < 0.05). Age at index procedure < 5 years had higher unplanned surgeries than age > 5 years (2.5 and 1.23 per patient, respectively,  p < 0.05). Type of implant and initial Cobb angle did not significantly affect the rate of unplanned surgeries (p  > 0.05) CONCLUSION: GSCs in EOS require a frequent revisit to operation room which should be well understood by the surgeon and parents.

Proximal junction kyphosis after posterior spinal fusion for early-onset scoliosis

STUDY DESIGN

Retrospective study.

OBJECTIVE

The aim of this study was to assess the presence of proximal junctional kyphosis (PJK) in our population of children with early-onset scoliosis (EOS) and to identify the predisposing factors for the development of PJK in the postoperative period after posterior spinal fusion (PSF). Few studies have been conducted to evaluate the incidence of proximal junction kyphosis (PJK) in children after early-onset scoliosis (EOS) after posterior spinal fusion (PSF).

MATERIALS AND METHODS

Overall, 114 pediatric patients aged < 10 years who underwent surgery for scoliosis or kyphoscoliosis at a single center between 2013 and 2015 were evaluated. Forty-five patients submitted to PSF of five or more levels met the inclusion criteria. The sample included 12 female and 10 male patients. Mean age at surgery was 7 years and 8 months.

RESULTS

PJK was observed in 22 patients (48.9%). Overall, the mean proximal junctional angle at 12 and 36 months was 17.1° and 22°, respectively. The uppermost instrumented vertebra (UIV) with the highest PJK rate was T6-T7. The lowest instrumented vertebra (LIV) with the highest PJK rate was L2. Etiology was idiopathic in 4, neuromuscular in 11, congenital in 14, and syndromic in 16. According to underlying disorder, prevalence of PJK was 78% in those with a congenital, 50% in those with a syndromic, 12% in those with idiopathic, and 9% in those with a neuromuscular EOS. Surgical revision rate was 4% (one patient). Mean postoperative follow-up was of 3 years and 4 months (range 3-4 years and 1 month).

CONCLUSION

Congenital and syndromic etiology, but not age at PJK onset or sex of the patient, significantly affected the incidence rate of PJK. The UIV with the highest PJK rate was T6-T7 and the LIV with the highest PJK rate was L2. The patients had a low surgical revision rate.

LEVEL OF EVIDENCE

Level IV.

The Association Between the Classification of Early-onset Scoliosis and Smith Complications After Initiation of Growth-friendly Spine Surgery: A Preliminary Study

BACKGROUND

Early-onset scoliosis (EOS) is a complex, heterogeneous condition involving multiple etiologies, genetic associations, and treatment plans. In 2014, Williams and colleagues proposed a classification system of EOS (C-EOS) that categorizes patients by etiology, Cobb angle, and kyphosis. Shortly after, Smith and colleagues validated a classification system to report complications of growth-friendly spine instrumentation. Severity refers to the level of care and urgency required to treat the complication, and can be classified as device-related or disease-related complications. The purpose of this study was to investigate if C-EOS can be used as a reliable predictor of Smith complications to better risk stratify these young, surgical patients.

METHODS

This study queried retrospective data from a large multicenter registry with regard to growth-friendly spine instrumentation in the EOS population. One-hundred sixteen patients were included in final data analysis to investigate the outcomes of their growth-friendly procedures according to the Smith complication classification system.

RESULTS

There were 245 Smith complications distributed among 116 patients included in this study (2.1 complications per patient). The majority of the complications were device related requiring at least one unplanned trip to the operating room (Smith Device Complication IIA or IIB; 111 complications). There were no complications that caused abandonment of growth-friendly instrumentation (Smith Complication III) and no mortalities (Smith Complication IV). The most severely affected EOS group was the hyperkyphotic syndromic group with a major curve angle >50 degrees (S3+), with 3.4 complications per patient. The least affect EOS group was the hyperkyphotic congenital group with a major curve angle between 20 and 50 degrees, with 0.3 complications per patient.

CONCLUSIONS

The C-EOS simplifies a complex pathology and the Smith complication classification scheme creates a language to discuss treatment of known complications of growth-friendly spine surgery. Although there is an association between more advanced C-EOS and Smith complications, there does not appear to be a correlation that can satisfy a risk stratification at this time.

LEVEL OF EVIDENCE

Level II.

Hybrid Growing Rod Technique of Osteotomy With Short Fusion and Spinal Distraction: An Alternative Solution for Long-Spanned Congenital Scoliosis

STUDY DESIGN

Retrospective study.

OBJECTIVE

The current study aimed to evaluate the effectiveness of the hybrid growing rod (GR) technique for the treatment of young children with congenital scoliosis (CS).

SUMMARY OF BACKGROUND DATA

Congenital vertebral anomalies within long-spanned kyphoscoliosis were difficult to be managed by either definitive spinal fusion or standard GR technique. Hybrid technique of one-stage posterior osteotomy with short fusion and GR distraction was proposed in previous studies. There is, however, paucity of data regarding its effectiveness.

METHODS

Thirteen patients (mean age, 5.4 ± 2.0 yr) who had undergone hybrid GR treatment were retrospectively reviewed, including 8 patients treated with single GR and 5 patients with dual GR. All of their radiographic data were measured, and surgical complications were recorded.

RESULTS

On average, the current cohort had 4.1 ± 1.7 lengthening procedures. After the index surgery, the major curve improved remarkably from 86.4° ± 11.9° to 37.3° ± 12.4° (P < 0.001). The global kyphosis significantly decreased from 66.8° ± 16.1° to 33.3° ± 3.5° postoperatively. Both value remained steady during follow-up. There were no significant difference between single GR and dual GR groups in terms of the coronal deformity correction, whereas correction loss of global kyphosis in single GR group was significantly higher than that in dual GR group (P = 0.039). After the index surgery, T1-S1 height averagely gained 4.4 ± 0.8 cm and it grew at an average rate of 1.31 ± 0.24 cm/yr during the follow-up. Two complications were identified in two patients, including one with rod fracture and one with proximal junctional kyphosis.

CONCLUSION

The hybrid GR technique was effective in correcting spinal deformity and allowing continuous spinal growth. The optimal indications were young children with apical vertebrae anomalies and a long-spanned kyphoscoliosis.

LEVEL OF EVIDENCE

3.

Treatment of early onset spinal deformities with magnetically controlled growing rods: a single centre experience of 30 cases

PURPOSE

The treatment of early onset scoliosis continues to be a major challenge, even when using motorized growth-sparing implants. We report on 30 cases operated on with magnetically controlled growing rods (MCGRs) at our institution, analyzing radiological parameters and complications, comparing our results with the literature and presenting a special implant fixation technique. A separate focus highlights the challenges of conversion from previous non-motorized implants.

METHODS

Consecutive case series. The nature and effects of complications were recorded for all patients. Radiographic evaluations were performed for patients with a minimum follow-up of two years. Separate analyses were carried out for patients who were previously treated with non-motorized growth-sparing implants.

RESULTS

There were 12 documented complications in 11/30 (37%) patients leading to 13 unplanned returns to the operating room. In all, 18/30 patients had a minimum follow-up of two years. Major curve and main kyphosis, as well as T1 to T12 and T1 to S1 distances significantly improved with MCGR implantation, however, less in patients converted from previous growth-sparing surgical treatment. While the achieved correction of the major curve was maintained, there was a loss of kyphosis correction with subsequent implant lengthening. Gain in implant length decreased with increasing number of extensions.

CONCLUSION

Despite improved patient's comfort, MCGR show a considerable complication rate. Coronal plane deformities can be well controlled, but diminished implant lengthening is already apparent within two years after MCGR implantation. Central databases should help to clarify unresolved aspects and optimize the treatment of these young patients.

LEVEL OF EVIDENCE

IV.

Superior Extension of Upper Instrumented Vertebrae in Distraction-based Surgery: A Surrogate for Clinically Significant Proximal Junctional Kyphosis

BACKGROUND

Proximal junctional kyphosis (PJK) is a reported complication of distraction-based growth-friendly surgery for early-onset scoliosis (EOS). A potential consequence of PJK is revision surgery with superior extension of the upper instrument vertebrae (UIV). The purpose of this study was to determine the risk of radiographic and clinically significant PJK during growth-friendly surgery.

METHODS

This is a retrospective review of children treated with distraction-based growth-friendly surgeries from two EOS registries with minimum two-year follow-up. PJK is defined as clinically significant in this study if surgery with superior extension of the UIV was performed.

RESULTS

Of 419 total patients, there was a 20% risk of developing clinically significant PJK (24% rib vs. 15% spine-based anchors, p = .03). These patients had a mean preoperative age of 5.6 years (5.2-year rib vs. 6.0-year spine, p < .001), scoliosis of 73° (69° rib vs. 77° spine, p < .001), and kyphosis of 51° (47° rib vs. 56° spine, p < .01). Regression analysis demonstrated that these differences in age, scoliosis, and kyphosis between anchor type did not account for a significant proportion of the measured variance.

CONCLUSIONS

There was a 20% risk of developing clinically significant PJK, with a slightly higher risk for patients treated with rib-based proximal anchors (24%) than for those patients treated with spine-based proximal anchors (15%).

LEVEL OF EVIDENCE

Level III.

Decision Making of Graduation in Patients With Early-Onset Scoliosis at the End of Distraction-Based Programs: Risks and Benefits of Definitive Fusion

STUDY DESIGN

Retrospective comparative analysis.

OBJECTIVE

Study early-onset scoliosis (EOS) graduated patients to establish founded criteria for graduation decision making and determine the risks and benefits of definitive fusion.

SUMMARY OF BACKGROUND DATA

EOS is treated by growth-friendly techniques until skeletal maturity. Afterwards, patients can be "graduated," either by definitive fusion (posterior spinal fusion [PSF]) or by retaining the previous implants (Observation) with no additional surgery. Criteria for this decision making and the outcomes of definitive fusion are still underexplored.

METHODS

We analyzed a consecutive cohort of "graduated" patients after a distraction-based lengthening program. We gathered demographic, radiographic, and surgical data. The results of the two final treatment options were compared after 2 years' follow-up.

RESULTS

A total of 32 patients were included. Four patients had incomplete records. Thirteen underwent PSF, and 15 were observed. The mean age at initial treatment was 8 ± 3 years, with a mean follow-up of 8.3 ± 2.9 years. Both groups had similar preoperative and final radiographic parameters (p > .05). The criteria for undergoing PSF were as follows: implant-related complications, main curve magnitude (PSF = 63.2° ± 9° vs. OBS = 47.9° ± 15°; p = .008), curve progression >10°, and sagittal misalignment (SVA). During PSF 12/13 patients underwent multiple osteotomies, one vertebrectomy, and 3 costoplasties. Surgical time was 291.5 ± 58 minutes; blood loss was 946 ± 375 mL; and the number of levels fused was 13.7. Coronal deformity was corrected 31%, T1-S1 length gained was 31 ± 19.6 mm and T1-T12 length gained was 9.3 ± 39 mm; kyphosis was reduced by 22%. However, coronal balance worsened by 2.3 ± 30.8 mm. No major complications were encountered in these patients.

CONCLUSIONS

Graduation by PSF depended on unacceptable or progressive major curve deformity, sagittal misalignment, or complications with previous implants. Observation depended on curve stabilization, Cobb <50°, and coronal misalignment <20 mm. Definitive fusion effectively corrected coronal and sagittal deformity and increased trunk height. However, it exposed patients to a very demanding surgery without improvement in coronal balance.

LEVEL OF EVIDENCE

Level III, therapeutic.

Early-Onset Scoliosis: Updated Treatment Techniques and Results

STUDY DESIGN

This is a review of the current literature on early-onset scoliosis (EOS) techniques and treatment written by the Growing Spine Committee of the Scoliosis Research Society.

OBJECTIVES

The Growing Spine Committee of the Scoliosis Research Society sought to update the information available on the definition and treatment of EOS, including new information about existing techniques.

SUMMARY OF BACKGROUND DATA

EOS represents a diverse, heterogeneous, and clinically challenging group of spinal disorders occurring in children under the age of 10. Our understanding of EOS has changed dramatically in the last 15 years, and management of EOS has changed even more rapidly in the last five years.

METHODS

The Growing Spine Committee of the Scoliosis Research Society has embarked upon a review of the most current literature on EOS techniques and treatment.

RESULTS

This white paper provides recent updates on current techniques, including a summary of new modalities, indications, contraindications, and clinical results.

CONCLUSIONS

Although treatment of EOS is still challenging and complicated, the evolution of options and knowledge presents hope for better understanding and management in the future.

LEVEL OF EVIDENCE

Level V.

Upper Instrumented Vertebrae Distal to T2 Leads to a Higher Incidence of Proximal Junctional Kyphosis During Growing-rod Treatment for Early Onset Scoliosis

STUDY DESIGN

A retrospective case series.

OBJECTIVE

We sought to evaluate the prevalence and risk factors of proximal junctional kyphosis (PJK) after growing-rod surgery in patients with early onset scoliosis (EOS).

SUMMARY OF BACKGROUND DATA

Growing-rod surgery is the primary treatment in patients with progressive EOS when conservative treatment fails. PJK is one of the most commonly reported postoperative complications.

MATERIALS AND METHODS

We retrospectively evaluated 50 patients (24 boys and 26 girls) diagnosed with EOS who underwent growing-rod surgery. Preoperative and follow-up demographic data, surgical strategies, and radiographic parameters were recorded and analyzed to identify PJK risk factors.

RESULTS

The mean age of patients at the time of the initial surgery was 8.6±2.5 years. Mean follow-up was 33.5±10.8 months, and mean number of lengthening surgeries were 2.14±1.52. Twenty-eight of the surgical procedures were single growing-rod surgeries, of which 22 were dual growing-rod surgeries. The upper instrumented vertebrae (UIV) ranged from C6-T6, and the lower instrumented vertebrae ranged from L1-S1. Ultimately, PJK developed in 14 (28%) of 50 patients. Taller patients, UIV distal to T2, and greater postoperative upper thoracic scoliosis (UTS) were suspected potential risk factors of PJK during the univariate analysis (P<0.1). Multifactorial regression analysis confirmed that UIV distal to T2 (hazard ratio=5.474; P=0.044) and postoperative UTS >50 degrees (hazard ratio=1.049; P=0.046) were the independent risk factors of PJK during growing-rod treatment in patients with EOS.

CONCLUSIONS

The prevalence of PJK was 28% during growing-rod treatment in EOS. The independent risk factors for PJK were UIV distal to T2 and postoperative UTS >50 degrees. It is important for spine surgeons to recognize these risk factors when planning surgeries, and counseling patients and families about this possible complication.

LEVEL OF EVIDENCE

Level III.

Evolution of the postoperative sagittal spinal profile in early-onset scoliosis: is there a difference between rib-based and spine-based growth-friendly instrumentation?

OBJECTIVE Although the vertical expandable prosthetic titanium rib (VEPTR) and growing rod instrumentation (GRI) encourage spinal growth via regular lengthening, they can create different results because of their different fixation patterns and mechanisms in correcting scoliosis. Previous studies have focused comparisons on coronal plane deformity with minimal attention to the sagittal profile. In this retrospective study, the authors aimed to compare the evolution of the sagittal spinal profile in early-onset scoliosis (EOS) treated with VEPTR versus GRI. METHODS The data for 11 patients with VEPTR and 22 with GRI were reviewed. All patients had more than 2 years' follow-up with more than 2 lengthening procedures. Radiographic measurements were performed before and after the index surgery and at the latest follow-up. The complications in both groups were recorded. RESULTS Patients in both groups had similar diagnoses, age at the index surgery, and number of lengthening procedures. The changes in the major coronal Cobb angle and T1-S1 spinal height were not significantly different between the 2 groups. Compared with the GRI group, the VEPTR group had less correction in thoracic kyphosis (23% ± 12% vs 44% ± 16%, p < 0.001) after the index surgery and experienced a greater correction loss in thoracic kyphosis (46% ± 18% vs 11% ± 8%, p < 0.001) at the latest follow-up. Although the increase in the proximal junctional angle was not significantly different (VEPTR: 7° ± 4° vs GRI: 8° ± 5°, p = 0.569), the incidence of proximal junctional kyphosis was relatively lower in the VEPTR group (VEPTR: 18.2% vs GRI: 22.7%). No significant changes in the spinopelvic parameters were observed, while the sagittal vertical axis showed a tendency toward a neutral position in both groups. The overall complication rate was higher in the VEPTR group than in the GRI group (72.7% vs 54.5%). CONCLUSIONS The VEPTR had coronal correction and spinal growth results similar to those with GRI. In the sagittal plane, however, the VEPTR was not comparable to the GRI in controlling thoracic kyphosis. Thus, for hyperkyphotic EOS patients, GRI is recommended over VEPTR.

Exercise Tolerance in Children With Early Onset Scoliosis: Growing Rod Treatment "Graduates"

STUDY DESIGN

Prospectively enrolled early-onset scoliosis (EOS) patients undergoing growing rod treatment, who have had no surgery for >1 year and/or have received definitive fusion (growing rod "graduates").

OBJECTIVES

To assess oxygen consumption during exercise and determine if a diminished conventional pulmonary function test (PFT) correlates with metabolic, pulmonary, and cardiovascular measures during exercise.

SUMMARY OF BACKGROUND DATA

Based on clinical impression and sequential PFT values, EOS patients who have undergone extensive treatment are thought to have limited capacity during exercise. The use of PFTs in this population has been a primary outcome measure of respiratory capacity; however, PFTs are dependent on effort, and thus subjective. This led us to find a new assessment of outcome, to better understand their pulmonary capacity.

METHODS

Patients underwent oxygen consumption (VO₂) testing while walking at self-selected speed over-ground and during a graded exercise test. Maximal VO₂ was predicted in those who completed the test to 85% of maximal heart rate (HR). Statistical analysis included Mann-Whitney U test and Spearman correlation coefficient (α = 0.05).

RESULTS

12 patients participated. Over-ground walking showed that EOS graduates chose to walk at the same speed, but at a higher VO₂ Cost (0.28 mL/kg/m) than controls (0.22 mL/kg/m; p < .001). Treadmill exercise testing showed 9 of 12 subjects able to complete the 85% of predicted maximum protocol. The EOS group had lower VO₂ during the final stage (27.9 mL/kg/min) compared to controls (34.2 mL/kg/min; p = .021); however, their heart rate reached the same values. Subjects completing the protocol had lower predicted VO₂ max (38.5 mL/kg/min) compared with controls (45.0 mL/kg/min), but this was not significant.

CONCLUSIONS

Although PFT data suggest clinically relevant pulmonary compromise in EOS patients, the current study shows that these children are able to keep up with their peers in daily activities and also have the capacity to exercise.

LEVEL OF EVIDENCE

Level II, therapeutic.

Incidence of proximal junctional kyphosis with magnetic expansion control rods in early onset scoliosis

BACKGROUND

The introduction of magnetic expansion control growth rods for the surgical management of EOS has gained popularity. However, there are no published studies on the incidence of proximal junctional kyphosis (PJK) using this technique.

PURPOSE

The aim of this study is to report the incidence of PJK following treatment with magnetic growth rods in EOS.

METHODS

Retrospective review of data from 21 cases (12 males, 9 females) over 3 years. PJK was obtained from whole spine X-rays pre-op, immediate post-op and last follow-up. Cobb angle was measured between the superior end plate of vertebra two levels above the upper instrumented vertebra (UIV) and the inferior end plate of the UIV. A difference of >10° between the pre-operative x-rays and the last follow-up X-rays was recorded as PJK.

RESULTS

6/21 (28.6 %) had proximal junctional kyphosis of more than 10° at last follow-up. Average age was 5.3. Average follow-up was 32.5 months. All the patients with PJK were syndromic. Four out of these six patients were males (66 %). Average PJK angle was 25.55°. Average pre-operative kyphosis was 52.5°. Average number of distractions was 7.4. All six patients had syndromic association. 3/6 patients (50 %) were conversion cases treated with traditional growth rods previously (TGR). None of the patients required unplanned surgery for PJK.

CONCLUSION

The incidence of PJK in EOS patients treated with magnetic rods is favourably comparable to that reported with traditional growth rods. Also, children who are male, syndromic, hyperkyphotic, and younger must be monitored closely.

Prevalence and Consequences of the Proximal Junctional Kyphosis After Spinal Deformity Surgery: A Meta-Analysis

The aim of this study was to estimate the prevalence and patient outcomes of proximal junctional kyphosis (PJK) in pediatric patients and adolescents who received surgical interventions for the treatment of a spinal deformity.Literature was searched in electronic databases, and studies were selected by following précised eligibility criteria. Percent prevalence values of the PJK in individual studies were pooled to achieve a weighted effect size under the random effects model. Subgroup and meta-regression analyses were performed to appraise the factors affecting PJK prevalence.Twenty-six studies (2024 patients) were included in this meta-analysis. Average age of the patients was 13.8 ± 2.75 years of which 32 ± 20 % were males. Average follow-up was 51.6 ± 38.8 (range 17 ± 13 to 218 ± 60) months. Overall, the percent prevalence of PJK (95% confidence interval) was 11.02 (10.5, 11.5) %; P < 0.00001 which was inversely associated with age (meta-regression coefficient: -1.607 [-2.86, -0.36]; 0.014). Revision surgery rate in the patients with PJK was 10%. The prevalence of PJK was positively associated with the proximal junctional angle at last follow-up (coefficient: 2.248; P = 0.012) and the change in the proximal junctional angle from surgery to last follow-up (coefficient: 2.139; P = 0.014) but not with preoperative proximal junctional angle.The prevalence of PJK in the children and adolescent patients is 11%. About 10% of those affected require revision surgery.