When Is a Growth-friendly Strategy Warranted? A Matched Comparison of Growing Rods Versus Primary Posterior Spinal Fusion in Juveniles With Early-onset Scoliosis

Predicting early return to the operating room in early-onset scoliosis patients using machine learning techniques

PURPOSE

Surgical treatment of early-onset scoliosis (EOS) is associated with high rates of complications, often requiring unplanned return to the operating room (UPROR). The aim of this study was to create and validate a machine learning model to predict which EOS patients will go on to require an UPROR during their treatment course.

METHODS

A retrospective review was performed of all surgical EOS patients with at least 2 years follow-up. Patients were stratified based on whether they had experienced an UPROR. Ten machine learning algorithms were trained using tenfold cross-validation on an independent training set of patients. Model performance was evaluated on a separate testing set via their area under the receiver operating characteristic curve (AUC). Relative feature importance was calculated for the top-performing model.

RESULTS

257 patients were included in the study. 146 patients experienced at least one UPROR (57%). Five factors were identified as significant and included in model training: age at initial surgery, EOS etiology, initial construct type, and weight and height at initial surgery. The Gaussian naïve Bayes model demonstrated the best performance on the testing set (AUC: 0.79). Significant protective factors against experiencing an UPROR were weight at initial surgery, idiopathic etiology, initial definitive fusion construct, and height at initial surgery.

CONCLUSIONS

The Gaussian naïve Bayes machine learning algorithm demonstrated the best performance for predicting UPROR in EOS patients. Heavier, taller, idiopathic patients with initial definitive fusion constructs experienced UPROR less frequently. This model can be used to better quantify risk, optimize patient factors, and choose surgical constructs.

LEVEL OF EVIDENCE

Prognostic: III.

Does radiographic calibration affect linear radiographic measurements in a large pediatric spine registry?

PURPOSE

Large registries are increasingly at the forefront of modern pediatric spine research, with manual, centralized, trained radiographic measurement serving as the gold standard for spine research. However, there is limited data regarding the reliability of registry measurements which may be subject to differences in radiographic calibration. We undertook this study to evaluate reliability of T1-T12 height, L1-S1 height, and coronal balance measurements for a large registry of early onset scoliosis patients.

METHODS

Three trained technicians from the Pediatric Spine Study Group measured 43 radiographs for T1-T12, L1-S1, and coronal balance using 3 different calibration techniques. All radiographs were AP views of patients with magnetically controlled growing rods with known diameters. The calibration techniques used a pre-export manually drawn line, a digital automatically generated computerized marker, and the diameter of a magnetically controlled growing rod. The intraclass correlation coefficient (ICC) was calculated to determine reliability.

RESULTS

1161 measurements were performed. For each of the three raters, coronal balance, T1-T12 height and L1-S1 height had excellent agreement regardless of the calibration technique (alpha 0.93-1.0). Among the parameters, coronal balance had the worst inter-rater reliability, whereas there was excellent interrater reliability regarding T1-T12 height and L1-S1 height (alpha 0.91-0.99).

CONCLUSION

There was excellent agreement among reviewers and between the 3 different calibration techniques. While calibration using rod diameter served as the gold standard, this data shows that other standard calibration methods were adequate and achieved excellent reliability for registry radiographs.

Growing Rod versus Posterior Spinal Fusion Treatment of Juvenile Idiopathic Scoliosis: Unique Characteristics and Surgical Outcomes

Progressive spinal curvature in juvenile idiopathic scoliosis (JIS) is challenging to treat. When conservative management fails, treatments include growing rods (GRs) or posterior spinal fusion (PSF). The purpose of this study is to compare the patient characteristics and outcomes of GR and PSF treatment of JIS. We performed a retrospective review of demographic, radiographic, and surgical data for all JIS patients requiring surgical treatment between 2012 and 2020. Patients who underwent any GR treatment were compared to PSF patients. A total of 36 patients (13 GR, 23 PSF) were reviewed. PSF patients had a larger pre-operative spinal height (p = 0.002), but similar pre-operative major curve magnitudes (p = 0.558). PSF treatment resulted in similar change in the T1-S1 length (p = 0.002), but a greater correction of the curve magnitude (p < 0.055) compared to GR patients. Eight patients initially treated with GRs later underwent definitive PSF treatment. This subset of patients had a greater spinal height before PSF (p = 0.006), but similar immediate post-PSF T1-S1 lengths (p = 0.437) and smaller changes in spinal height from PSF (p = 0.020) than primary PSF patients. At final follow-up, patients who underwent primary PSF versus PSF after GR had similar spinal heights (p = 0.842). The surgical intervention chosen to manage progressive JIS often differs based on patient characteristics. While this choice may impact immediate outcomes, the outcomes at final follow up are similar.

Radiographic and clinical outcomes after definitive spine fusion for skeletally immature patients with idiopathic scoliosis

PURPOSE

To assess the intermediate-term radiographic and clinical outcomes of skeletally immature idiopathic scoliosis (IS) patients that underwent definitive fusion (DF).

METHODS

A retrospective review of patients with IS who were Risser 0 with open tri-radiate cartilages at the time of DF with minimum 5-year follow-up. Outcomes included Scoliosis Research Society (SRS)-30 scores, major Cobb angle, pulmonary function tests (PFTs), and unplanned returns to the operating room (UPROR). Adding-on was defined as progression of the major Cobb angle > 5° or tilt of the lowest instrumented vertebra > 5°.

RESULTS

Thirty-two patients (78% female, mean age 12.2 ± 1.3 years old, mean preoperative major Cobb 64.8° ± 15.9) were included. Of these patients, 20 (62.5%) experienced adding-on and 6 (18.8%) required a revision surgery to correct their progressive spinal deformity. Adding-on was associated with lower 5-year postoperative SRS scores for appearance (3.7 ± 0.7 vs 4.4 ± 0.3, p = 0.0126), mental health (4.2 ± 0.6 vs 4.6 ± 0.3, p = 0.0464), satisfaction with treatment (4.0 ± 0.8 vs 4.7 ± 0.4, p = 0.0140), and total score (4.0 ± 0.4 vs 4.4 ± 0.2, p = 0.0035). The results of the PFTs did not differ between groups. Patients experienced an average of 0.53 UPROR/patient.

CONCLUSION

DF in skeletally immature patients results in a high rate of adding-on, which adversely affects Health-Related Quality of Life. However, reoperation rates, both planned and unplanned, remain lower when compared to patients undergoing growth-friendly treatment.

Comparison of treatment outcomes between growth-sparing instrumentation and definitive one-stage fusion for EOS patients ages 6-10 years

PURPOSE

To compare objective outcomes for EOS patients age 6-10 years treated by growth-sparing (GS) surgery or definitive one-stage correction and fusion (DF).

METHODS

We reviewed surgical, radiographic, PFT's, and EOSQ-24 outcomes for EOS patients > age 6 at index surgery treated at a single institution, minimum 2-year follow-up. Neuromuscular diagnoses were excluded.

RESULTS

47 patients underwent index surgery between age 6 and 10.9 years. Twenty-one had DF, 26 had GS surgery (13 MCGR, 13 TGR). Diagnoses included 15 congenital, 15 idiopathic, 17 syndromic. Age at index was 9.1 years DF, 7.8 GS (p < .001). Follow-up was 63-78 months. 18/26 GS cases converted to DF, 13 due to complications, which occurred in 8/21 DF cases vs 19/26 GS (p = .016). DF patients had fewer post-index surgeries (0.6 vs 3.7, p < .001). At follow-up there were no differences in curve magnitudes, %correction, T1-12/T1-S1 segment lengths, EOSQ-24 scores or PFTs. 18 patients converting to DF after initial GS had equal outcomes as DF initially. 31 patients > age 8 at index ("tweeners") were studied separately. 13 had GS surgery (7 MCGR), 18 had DF. At > 60 months follow-up, curve magnitudes, spine lengths, PFT's, or EOSQ scores were equivalent. DF patients had fewer procedures and complications.

CONCLUSION

For patients age 6-10.9 years, outcomes were no different at > 5 year follow-up between DF and GS groups. DF patients had fewer total surgeries and complications. Equal outcomes also occurred for tweeners. As a result, GS treatment does not appear to benefit patients > age 8.

Early Development of Spinal Deformities in Children Severely Affected with Spinal Muscular Atrophy after Gene Therapy with Onasemnogene Abeparvovec-Preliminary Results

Spinal muscular atrophy (SMA) is a rare genetic disorder, with the most common form being 5q SMA. Survival of children with severe SMA is poor, yet major advances have been made in recent years in pharmaceutical treatment, such as gene-therapy, which has improved patient survival. Therefore, clinical problems, such as the development of spinal deformities in these genetically treated SMA children represent an unknown challenge in clinical work. In a retrospective case series, the development of spinal deformities was analyzed in 16 SMA children (9 male, 7 female) treated with onasemnogene abeparvovec in two institutions during the years 2020 to 2022. Ten out of sixteen patients had a significant kyphosis, and nine out of sixteen patients had significant scoliosis, with the mean curvature angles of 24 ± 27° for scoliosis, and 69 ± 15° for kyphosis. Based on these preliminary data, it can be assumed that early-onset kyphosis presents a clinical challenge in gene-therapy-treated SMA children. Larger datasets with longer follow-up times need to be collected in order to verify these preliminary observations.

Three-dimensional correction of scoliosis by a double spring reduction system as a dynamic internal brace: a pre-clinical study in Göttingen minipigs

BACKGROUND CONTEXT

Adolescent idiopathic scoliosis (AIS) is a major skeletal deformity that is characterized by a combination of apical rotation, lateral bending and apical lordosis. To provide full 3D correction, all these deformations should be addressed. We developed the Double Spring Reduction (DSR) system, a (growth-friendly) concept that continuously corrects the deformity through two different elements: A posterior convex Torsional Spring Implant (TSI) that provides a derotational torque at the apex, and a concave Spring Distraction System (SDS), which provides posterior, concave distraction to restore thoracic kyphosis.

PURPOSE

To determine whether the DSR components are able to correct an induced idiopathic-like scoliosis and to compare correction realized by the TSI alone to correction enforced by the complete DSR implant.

STUDY DESIGN/SETTING

Preclinical randomized animal cohort study.

PATIENT SAMPLE

Twelve growing Göttingen minipigs.

OUTCOME MEASURES

Coronal Cobb angle, T10-L3 lordosis/kyphosis, apical axial rotation, relative anterior lengthening.

METHODS

All mini-pigs received the TSI with a contralateral tether to induce an idiopathic-like scoliosis with apical rotation (mean Cobb: 20.4°; mean axial apical rotation: 13.1°, mean lordosis: 4.9°). After induction, the animals were divided into two groups: One group (N=6) was corrected by TSI only (TSI only-group), another group (N=6) was corrected by a combination of TSI and SDS (DSR-group). 3D spinal morphology on CT was compared between groups over time. After 2 months of correction, animals were euthanized.

RESULTS

Both intervention groups showed excellent apical derotation (TSI only-group: 15.0° to 5.4°; DSR-group: 11.2° to 3.5°). The TSI only-group showed coronal Cobb improvement from 22.5° to 6.0°, while the DSR-group overcorrected the 18.3° Cobb to -9.2°. Lordosis was converted to kyphosis in both groups (TSI only-group: -4.6° to 4.3°; DSR-group: -5.2° to 25.0°) which was significantly larger in the DSR-group (p<.001).

CONCLUSIONS

The TSI alone realized strong apical derotation and moderate correction in the coronal and sagittal plane. The addition of distraction on the posterior concavity resulted in more coronal correction and reversal of induced lordosis into physiological kyphosis.

CLINICAL SIGNIFICANCE

This study shows that dynamic spring forces could be a viable method to guide the spine towards healthy alignment, without fusing it or inhibiting its growth.

Definition of Tweener: Consensus Among Experts in Treating Early-onset Scoliosis

BACKGROUND

The term "Tweener" is colloquially used to refer to early-onset scoliosis (EOS) patients whose age and development make them candidates for multiple surgical options. The purpose of this study was to establish expert consensus on a definition to formally characterize the Tweener population.

METHODS

A 3-round survey of surgeons in an international EOS study group was conducted. Surgeons were provided with various patient characteristics and asked if each was part of their definition for Tweener patients. Responses were analyzed for consensus (≥70%), near-consensus (60% to 69%), and no consensus (<60%).

RESULTS

Consensus was reached (89% of respondents) for including chronological age in the Tweener definition; 8 to 10 years for females and 9 to 11 years for males. Surgeons agreed for inclusion of Sanders score, particularly Sanders 2 (86.0%). Patients who have reached Sanders 4, postmenarche, or have closed triradiate cartilage should not be considered Tweeners. Bone age range of 8 years and 10 months to 10 years and 10 months for females (12 y for males) could be part of the Tweener definition.

CONCLUSIONS

This study suggests that the Tweener definition could be the following: patients with open triradiate cartilage who are not postmenarche and have not reached Sanders 4, and if they have one of the following: Sanders 2 or chronological age 8 to 10 years for females (9 to 11 y for males) or bone age 8 years and 10 months to 10 years and 10 months for females (12 y for males). This definition will allow for more focused and comparative research on this population.

LEVEL OF EVIDENCE

Level V-expert opinion.

Changes in research quality and surgical trends at the international congress on early-onset scoliosis

PURPOSE

The founding of the International Congress for Early Onset Scoliosis (ICEOS) and first annual meeting in 2007 represented a significant milestone in advancing the care of patients with EOS. Due to the complexity and rarity of EOS, this annual conference is the premiere venue for physicians, researchers, and advanced practice providers to identify and understand the best treatments for children with EOS. This study examines the trend of various treatment modalities presented at ICEOS and the changes in research quality since its inception.

METHODS

Podium presentations from the 2007 through 2021 ICEOS annual meetings were reviewed to determine the number of study patients, use of a study group, and key features of study design. Treatment strategies being evaluated were recorded and included non-operative treatments (casting/bracing), traditional growing rods (TGR), vertical expandable prosthetic titanium rib (VEPTR), Shilla growth guidance, magnetically controlled growing rods (MCGR), and vertebral body tethering (VBT). Linear regressions were performed to analyze changes in research topic and study group utilization.

RESULTS

A total of 532 abstracts were reviewed. An average of 97.5 ± 81.3 patients were included per study with a significant increase from 42.3 ± 89.7 in 2007 to 337.6 ± 587.4 in 2021 (r² = 0.632, p < 0.001). A total of 130 (24.4%) abstracts resulted from multicenter study groups with the proportion increasing significantly from 13.0% in 2007 to 36.4% in 2021 (p = 0.039, r² = 0.289). The majority (96.2%) of study group-based projects were from either the Growing Spine Study Group (GSSG), Chest Wall and Spine Deformity Study Group (CWSDG), Children's Spine Study Group (CSSG), or the Pediatric Spine Study Group (PSSG). Additionally, a significant increase in studies utilizing patient-reported outcome measures (PROMs) was observed (r² = 0.336, p = 0.023). Significant increases in the proportion of presentations discussing MCGR (r² = 0.738, p < 0.001) and VBT (r² = 0.294, p = 0.037) as surgical treatments were observed.

CONCLUSION

The trends in EOS device implantation observed in registry studies align with the trends in research presented at ICEOS including the increased proportion of studies focusing on MCGR and VBT over the past decade. An attempt to increase the quality of research presented at ICEOS through multicenter study groups, increased patient recruitment, and utilization of PROMs has been seen since its inception.

LEVEL OF EVIDENCE

V.

Definitive fusions are better than growing rod procedures for juvenile patients with cerebral palsy and scoliosis: a prospective comparative cohort study

PURPOSE

This study compared the outcomes of juvenile patients with cerebral palsy (CP) and scoliosis who underwent spinal fusion (SF) versus growing rod (GR) surgery.

METHODS

Two prospective multicenter registries were queried for patients 8-10 years old with minimum 2-year follow-up who underwent SF or GR surgery (no MCGR). Demographics, radiographs, complications, and outcome scores were recorded.

RESULTS

There were 35 patients in the SF and 15 in the GR group. The mean age at surgery was 10 and 9.3 years in the SF and GR groups, respectively (p = 0.004). In the SF group preoperatively, the major curve measured 86° and 80° in the GR group (p = 0.40). "Definitive" surgery in the GR group consisted of SF in 10, implant retention in three, and implant removal in two. The SF group had 60.8% and the GR group had 45.0% correction following "definitive" surgery (p = 0.03). In the SF group, 8 patients and in the GR group, 9 patients (SF = 22.9%, GR = 60.0%) had a complication (p = 0.01). In the SF group, two patients (5.7%) had reoperations for infection; eight patients (53.3%) in the GR group had reoperations for infection and implant complications (p < 0.001). In the SF group, 23/30 parents (76.6%) noted that the child's life "improved a lot." In the GR group, 3/6 parents (50.0%) noted they were "neutral" about their child's ability to do things, 2/6 (33.3%) were "very dissatisfied."

CONCLUSIONS

SF treatment for juvenile patients with CP and scoliosis resulted in fewer complications and unplanned reoperations and better radiographic outcomes compared with GR. Quality of life improvements were also better in the SF group.

LEVEL OF EVIDENCE

Level III.

Outcomes of Definitive Spine Fusion Using All-pedicle-Screw Constructs in Skeletally Immature Patients Aged 8 to 10 Years With Severe Idiopathic Early-Onset Scoliosis

BACKGROUND

The choice between growth-sparing techniques or definitive spine fusion for severe idiopathic early-onset scoliosis (IEOS) in skeletally immature patients aged 8 to 10 years represents a challenging dilemma. Although growth-sparing techniques show high complication rates in severe IEOS, the outcomes of definitive fusion in borderline skeletally immature patients with severe IEOS have not been investigated. We aimed to investigate the outcomes of early definitive fusion using all-pedicle-screw constructs in skeletally immature patients aged 8 to 10 years with severe IEOS.

METHODS

The inclusion criteria were as follows: IEOS, age 8 years or above, major coronal curve ≥90 degrees, thoracic height >18 cm, no history of previous spine surgery, no intraspinal anomalies and at least 3 years of postoperative follow-up. Patients underwent instrumented spinal fusion with all-pedicle-screw constructs and multiple Ponte osteotomies. All patients completed the Scoliosis Research Society 22 revision (Arabic version) questionnaire and Body Image Disturbance Questionnaire-Scoliosis version (BIDQ-S) preoperatively and at the last follow-up.

RESULTS

Fifty-five patients (24 males, 31 females; mean age: 8.96 y; range: 8 to 10 y) with severe IEOS met the inclusion criteria (mean follow-up period: 4.1±0.6 y; range: 3 to 5 y). The mean major coronal Cobb angle improved significantly (P<0.001) from 107±12.5 degrees to 26.8±6.8 degrees. Mean thoracic kyphosis improved significantly (P<0.001) from 57.2±15.8 degrees to 31.2±4.4 degrees. The loss of correction at the latest follow-up was nonsignificant. The total Scoliosis Research Society 22 revision (SRS-22r) score improved significantly from 2.5±1 to 4.3±0.7. The mean BIDQ-S score improved significantly from 4.1±0.3 to 1.6±0.3. The immediate postoperative gains in the mean thoracic height (T1-T12) and spinal height (T1-S1) were 14.9% and 19.6%, respectively, and the overall height increase at the latest follow-up was 17.8% and 23.8%, respectively. One patient underwent revision for implant failure (rod breakage).

CONCLUSION

Early definitive fusion for skeletally immature patients with severe IEOS yielded excellent correction with major improvements in patient quality of life. Severe IEOS poses a significant risk, but definitive fusion can potentially mitigate that risk in patients aged 8 to 10 years.