Analysis of three-dimensional spine growth for vertebral body tethering patients at 2 and 5 years post operatively.

PURPOSE: Scoliosis can be treated with vertebral body tethering (VBT) as a motion-sparing procedure. However, the knowledge of how growth is affected by a tether spanning multiple levels is unclear in the literature. Three-dimensional true spine length (3D-TSL) is a validated assessment technique that accounts for the shape of the spine in both the coronal and sagittal planes. This study aimed to assess if 3D-TSL increases over a five-year period after VBT implantation in thoracic curves for idiopathic scoliosis. METHODS: Prospectively collected radiographic data from an international pediatric spine registry was analyzed. Complete radiographic data over three visits (post-operative, 2 years, and 5 years) was available for 53 patients who underwent VBT. RESULTS: The mean age at instrumentation of this cohort was 12.2 (9-15) years. The average number of vertebrae instrumented was 7.3 (SD 0.7). Maximum Cobb angles were 50° pre-op, which improved to 26° post-op (p < 0.001) and was maintained at 5 years (30°; p = 0.543). Instrumented Cobb angle was 22° at 5 years (p < 0.001 vs 5-year maximum Cobb angle). An accentuation was seen in global kyphosis from 29° pre-operative to 41° at 5 years (p < 0.05). The global spine length (T1-S1 3D-TSL) started at 40.6 cm; measured 42.8 cm at 2 years; and 44.0 cm at the final visit (all p < 0.05). At 5 years, patients reached an average T1-S1 length that is comparable to a normal population at maturity. Immediate mean post-operative instrumented 3D-TSL (top of UIV-top of LIV) was 13.8 cm two-year length was 14.3 cm; and five-year length was 14.6 cm (all p < 0.05). The mean growth of 0.09 cm per instrumented level at 2 years was approximately 50% of normal thoracic growth. Patients who grew more than 0.5 cm at 2 years had a significantly lower BMI (17.0 vs 19.0, p < 0.05) and smaller pre-operative scoliosis (48° vs 53°, p < 0.05). Other subgroup analyses were not significant for age, skeletal maturity, Cobb angles or number of spanned vertebras as contributing factors. CONCLUSIONS: This series demonstrates that 3D-TSL increased significantly over the thoracic instrumented levels after VBT surgery for idiopathic scoliosis. This represented approximately 50% of expected normal thoracic growth over 2 years.

Differential vertebral body growth is maintained after vertebral body tethering surgery for idiopathic scoliosis: 4-year follow-up on 888 peri-apical vertebrae and 592 intervertebral discs.

PURPOSE: To radiographically evaluate if vertebral body tethering (VBT) can maintain differential peri-apical vertebral growth at medium-term follow-up of 4 years. METHODS: A prospective, international, multicenter database was queried to identify idiopathic scoliosis patients treated with thoracic VBT. Concave vs. convex vertebral body height, vertebral wedging, and disc wedging of the 3 peri-apical vertebrae were measured by two independent observers at 5 timepoints (pre-operative to 4-year follow-up). RESULTS: 65 skeletally immature patients (60 female, mean 12.8 years old, 21 with open triradiate cartilages) met inclusion criteria. Mean pre-operative maximum scoliosis of 50 ± 8° decreased significantly post-operatively to 27 ± 9° (p < 0.001), which remained stable at 4-year follow-up 30 ± 17° (p = 0.38 vs. post-operative). Mean instrumented scoliosis was 21 ± 14° at 4-year follow-up, which was significantly different than 4-year maximum scoliosis (p < 0.001). Mean pre-operative kyphosis of 30 ± 12° did not significantly change post-operatively (p = 1.0) and remained stable at 4-year follow-up (35 ± 18°; p = 0.05). Mean individual convex vertebral height increased from 17.7 ± 1.9 mm to 19.8 ± 1.5 mm (p < 0.001), while mean individual concave height increased from 14.8 ± 1.9 mm to 17.6 ± 1.6 mm (p < 0.001). Summing the peri-apical heights, the difference in height from pre-operative to 4-year follow-up was greater on the concave (8.3 ± 4.7 mm) than on the convex side (6.2 ± 4.7 mm) (p < 0.001). Mean individual vertebral wedging decreased from 6 ± 2° at pre-operative to 4 ± 2° at 4-year follow-up (p < 0.001). Mean total vertebral and disc wedging started at 29 ± 7° pre-operatively, decreased to 16 ± 6° at post-operative (p < 0.001), then further decreased to 14 ± 8° at 4-year follow-up (p < 0.001). Patients with open triradiate cartilages at the time of surgery had a larger height change over the 4 years compared to those with closed triradiate cartilages (p < 0.001). CONCLUSION: Patients with idiopathic scoliosis treated with VBT demonstrated differential vertebral growth which was maintained at minimum 4-year follow-up. This effect was more pronounced in patients whose triradiate cartilages were open at the time of surgery. LEVEL OF EVIDENCE: III.

Do Caregivers and Patients With Early-Onset Scoliosis Share the Same Perspective on Health-Related Quality of Life? A Comparison of 24-item Early-Onset Scoliosis Questionnaire and 22-item Scoliosis Research Society Questionnaire Scores.

OBJECTIVE: The 24-item Early-Onset Scoliosis Questionnaire (EOSQ-24) is validated in patients with early onset scoliosis (EOS) aged 0 to 18 years and the 22-item Scoliosis Research Society (SRS-22) questionnaire is validated in idiopathic scoliosis patients 10 years and older. EOSQ-24 is completed by the caregiver and SRS-22 is completed by the patient. A prior study comparing patient-reported outcome measures completed by older pediatric patients and their parents showed a low level of agreement. Our purpose was to compare EOSQ-24 and SRS-22 scores completed at the same time point and at subsequent time points, in patients aged 5 to 18 years with idiopathic or congenital EOS without developmental delay. METHODS: This was a multicenter retrospective study. We identified pairs of EOSQ-24 and SRS-22 completed on the same day or within 6 months. Some patients had multiple pairs of surveys over time. EOSQ-24 and SRS-22 questions were matched and domain scores for Pain, Function, Mental Health, and Satisfaction were compared. Patients with a change in treatment between surveys were excluded. Pearson correlation coefficients ( r ) were used to compare domain scores, with r ≥0.7 indicating a strong relationship. RESULTS: There were 228 patient-caregiver dyads who completed 411 pairs of EOSQ-24 and SRS-22 on the same day. A strong correlation was found only for the Pain domain ( r =0.77). Function, Mental Health, and Satisfaction domains had positive but not strong correlations ( r = 0.58, r = 0.50, r = 0.41, respectively). Subanalysis based on age also showed a strong correlation only for Pain. There were 76 patient-caregiver dyads who completed 134 pairs of surveys with SRS-22 completed within 6 months after an EOSQ-24. All domains demonstrated a positive but not strong correlation, with Pain showing the highest correlation ( r = 0.64). CONCLUSIONS: EOSQ-24 and SRS-22 had a strong correlation only for Pain when completed at the same time point. EOSQ-24 and SRS-22 completed within 6 months lacked a strong correlation for all domains. Our findings suggest that parents and children with EOS may not share the same perspective on their health. Self-reported questionnaires should be used when possible to assess health-related quality of life in older children and adolescents with EOS who are developmentally neurotypical. LEVEL OF EVIDENCE: Level III-diagnostic.

Coronal decompensation following thoracic vertebral body tethering in idiopathic scoliosis.

PURPOSE: Post-operative coronal decompensation (CD) continues to be a challenge in the treatment of adolescent idiopathic scoliosis (AIS). CD following selective spinal fusion has been studied. However, there is currently little information regarding CD following Vertebral Body Tethering (VBT). Thus, the goal of this study is to better understand the incidence and risk factors for CD after VBT. METHODS: Retrospective review of a prospective multicenter database was used for analysis. Inclusion criteria were patients undergoing thoracic VBT, a minimum 2-year follow-up, LIV was L1 or above, skeletally immature (Risser ≤ 1), and available preoperative and final follow-up AP and lateral upright radiographs. Radiographic parameters including major and minor Cobb angles, curve type, LIV tilt/translation, L4 tilt, and coronal balance were measured. CD was defined as the distance between C7PL and CSVL > 2 cm. Multiple logistic regression model was used to identify significant predictors of CD. RESULTS: Out of 136 patients undergoing VBT, 94 patients (86 female and 6 male) met the inclusion criteria. The mean age at surgery was 12.1 (9-16) and mean follow-up period was 3.4 years (2-5 years). Major and minor curves, AVR, coronal balance, LIV translation, LIV tilt, L4 tilt were significantly improved after surgery. CD occurred in 11% at final follow-up. Lenke 1A-R (24%) and 1C (26%) had greater incidence of CD compared to 1A-L (4%), 2 (0%), and 3 (0%). LIV selection was not associated with CD. Multivariate logistic regression analysis yielded 1A-R and 1C curves as a predictor of CD with the odds ratio being 17.0. CONCLUSION: CD occurred in 11% of our thoracic VBT patients. Lenke 1A-R and 1C curve types were predictors for CD in patients treated with VBT. There were no other preoperative predictors associated with CD.

Anterior vertebral body tethering shows clinically comparable shoulder balance outcomes to posterior spinal fusion.

PURPOSE: Posterior spinal fusion (PSF) is the current gold standard in surgical treatment for adolescent idiopathic scoliosis. Vertebral body tethering (VBT) is a fusionless alternative. Shoulder balance is an important metric for outcomes and patient satisfaction. Here we compare shoulder balance outcomes between PSF and VBT. METHODS: In this retrospective review, the pre-operative and post-operative absolute radiographic shoulder height (|RSH|) of 45 PSF patients were compared to 46 VBT patients. Mean values were compared and then collapsed into discrete groups (|RSH| GROUP) and compared. Patients were propensity score matched. Regression models based on pretest-posttest designs were used to compare procedure type on post-operative outcomes. RESULTS: Pre-operatively there were no differences in |RSH| between PSF and VBT, however, at latest post-operative follow-up PSF maintained a larger |RSH| imbalance compared to VBT (0.91 cm vs 0.63 cm, p = 0.021). In an ANCOVA regression, PSF was associated with a larger |RSH| imbalance compared to VBT, F(1, 88) = 5.76, p = 0.019. An ordinal logistic regression found that the odds ratio of being in a worse |RSH| GROUP for PSF vs VBT is 2.788 (95% CI = 1.099 to 7.075), a statistically significant effect χ2(1) = 4.658, p = 0.031. Results were similar in subgroup analyses of Lenke 1 and Lenke 2 patients, though to less statistical significance. CONCLUSION: While PSF was found to be associated with worse |RSH| outcomes, the actual numbers (2-3 mm) are unlikely to be clinically meaningful. Thus, in this analysis, VBT can be said to show comparable shoulder balance outcomes to PSF.

Prospectively Collected Comparison of Outcomes Between Surgically and Conservatively Treated Patients with Adolescent Idiopathic Scoliosis.

STUDY DESIGN: Retrospective review of a prospectively collected multicenter registry. OBJECTIVE: To evaluate health-related quality of life (HRQOL) measures in an operative cohort of patients (OP) and compare them with a matched nonoperative cohort (NON). SUMMARY OF BACKGROUND DATA: Historically, the surgical outcomes of adolescent idiopathic scoliosis (AIS) have been radiographically evaluated. However, the importance of HRQOL measures and their impact on surgical outcomes are increasingly being understood. METHODS: We identified 90 NON patients with curves in the operative range who were observed for at least 2 years. These patients were matched with an OP cohort of 689 patients. All patients completed the Scoliosis Research Society-22 (SRS-22) questionnaire at the initial evaluation and at a minimum of 2-year follow-up. Subgroup comparisons were based on curve type: primary thoracic (Th), primary thoracolumbar/lumbar (TL/L), and double major (DM) curves. RESULTS: The preoperative major curves in the Th, TL/L, and DM OP subgroups averaged 50.4°, 45.4°, and 51.5°, respectively, and 49.4°, 43.7°, and 48.9° in the NON cohort (P > 0.05). At 2 years postoperatively, the major curve in the Th, TL/L, and DM OP subgroups improved to 19.0°, 19.2°, and 19.3°, respectively, compared to the progression to 51.3°, 44.5°, and 49.7° in the NON group at 2-year follow-up (P < 0.05). The SRS-22 self-image, mental health, satisfaction, and total scores at the 2-year follow-up were significantly better in all OP subgroups (P < 0.001) but remained largely unchanged in the NON group. A significant percentage of patients (P < 0.001) in the OP cohort reported better SRS-22 scores at the 2-year follow-up in the self-image, mental health, and satisfaction domains than the NON group at 2 years. CONCLUSIONS: Surgically treated patients with AIS have improved HRQOL outcomes in several domains compared to age- and curve magnitude-matched nonoperatively treated patients at 2-year follow-up.

Vertebral body tethering for Lenke 1A curves: the lumbar modifier predicts less optimal outcomes.

INTRODUCTION: The addition of the L4 "AR" and "AL" lumbar modifier for Lenke 1A idiopathic scoliosis (IS) has been shown to direct treatment in posterior spinal fusion; however, its utility in vertebral body tethering (VBT) has yet to be evaluated. METHODS: A review of a prospective, multicenter database for VBT in IS was performed for patients with Lenke 1A deformities and a minimum of 2 years follow-up. Patients were categorized by their lumbar modifier (AR vs AL). Less optimal VBT outcome (LOVO) was defined as a final coronal curve > 35°, lumbar adding-on, or revision surgery for deformity progression or adding-on. RESULTS: Ninety-nine patients met inclusion criteria (81% female, mean 12.6 years), with 55.6% being AL curves. Overall, there were 23 instances of tether breakage (23.3%) and 20 instances of LOVO (20.2%). There was a higher rate of LOVO in AR curves (31.8% vs 10.9%, P = 0.01). Patients with LOVO had greater preoperative deformity, greater apical translation, larger coronal deformity on first erect radiographs, and less coronal deformity correction. Failure to correct the deformity < 30° on first erect was associated with LOVO, as was LIV selection short of the last touch vertebra (TV). Independent risk factors for LOVO included AR curves (OR 3.4; P = 0.04) and first erect curve magnitudes > 30 degrees (OR 6.0; P = 0.002). DISCUSSION: There is a 20.2% rate of less optimal VBT following VBT for Lenke 1A curves. AR curves are independently predictive of less optimal outcomes following VBT and require close attention to LIV selection. Surgeons should consider achieving an initial coronal correction < 30 degrees and extending the LIV to at least the TV to minimize the risk of LOVO.

Double major curvature treated with vertebral body tethering of both curves: how do outcomes compare to posterior spinal fusion?

PURPOSE: Vertebral body tethering (VBT) is a non-fusion alternative to posterior spinal fusion (PSF). There have been few reports on VBT of two curvatures. We aim to compare the radiographic outcomes between VBT and PSF in patients with double curvatures in which both curves were instrumented. METHODS: 29 AIS patients matched by Lenke, age (± 2 years), triradiate cartilage closure status, major Cobb angle (± 8°), and T5-T12 kyphosis (± 10°). Variables were compared using Wilcoxon rank-sum tests, Student's t tests, and chi-Square. Clinical success was defined as major curve < 35°. RESULTS: Group baseline demographics were similar. Major thoracic (T) curve types had significantly better major (VBT 51.5 ± 7.9° to 31.6 ± 12.0° [40%] vs. PSF 54.3 ± 7.4° to 17.4 ± 6.5° [68%]; p = 0.0002) and secondary curve correction in the PSF group. 71% of major T VBT patients were clinically successful versus 100% of PSF. Major thoracolumbar (TL) curve types experienced comparable major (VBT 52.3 ± 7.0° to 18.3 ± 11.4° (65%) vs. PSF 53.0 ± 5.2° to 23.8 ± 10.9° (56%); p = 0.2397) and secondary curve correction. 92% of major TL VBT patients were clinically successful versus 75% in the PSF group. There was no difference in T5-12 kyphosis or lumbar lordosis between groups for any curve type. There were 4 patients (13.8%) with major complications in the VBT group compared to 0 (0%) in the PSF. CONCLUSION: Patients with double major AIS who underwent VBT with major T curve types had less correction than PSF; however, those with major TL curves experienced similar radiographic outcomes regardless of procedure. Complications were greater for VBT.

Incidence of Tether Breakage in Anterior Vertebral Body Tethering.

BACKGROUND: Thoracic anterior vertebral body tethering (TAVBT) is an emerging treatment for adolescent idiopathic scoliosis. Tether breakage is a known complication of TAVBT with incompletely known incidence. We aim to define the incidence of tether breakage in patients with adolescent idiopathic scoliosis who undergo TAVBT. The incidence of tether breakage in TAVBT is hypothesized to be high and increase with time postoperatively. METHODS: All patients with right-sided, thoracic curves who underwent TAVBT with at least 2 and up to 3 years of radiographic follow-up were included. Tether breakage between 2 vertebrae was defined a priori as any increase in adjacent screw angle >5 degrees from the minimum over the follow-up period. The presence and timing of tether breakage were noted for each patient. A Kaplan-Meier survival analysis was performed to calculate expected tether breakage up to 36 months. χ 2 analysis was performed to examine the relationship between tether breakage and reoperations. Independent t test was used to compare the average final Cobb angle between cohorts. RESULTS: In total, 208 patients from 10 centers were included in our review. Radiographically identified tether breakage occurred in 75 patients (36%). The initial break occurred at or beyond 24 months in 66 patients (88%). Kaplan-Meier survival analysis estimated the cumulative rate of expected tether breakage to be 19% at 24 months, increasing to 50% at 36 months. Twenty-one patients (28%) with a radiographically identified tether breakage went on to require reoperation, with 9 patients (12%) requiring conversion to posterior spinal fusion. Patients with a radiographically identified tether breakage went on to require conversion to posterior spinal fusion more often than those patients without identified tether breakage (12% vs. 2%; P =0.004). The average major coronal curve angle at final follow-up was significantly larger for patients with radiographically identified tether breakage than for those without tether breakage (31 deg±12 deg vs. 26 deg±12 deg; P =0.002). CONCLUSIONS: The incidence of tether breakage in TAVBT is high, and it is expected to occur in 50% of patients by 36 months postoperatively. LEVEL OF EVIDENCE: Level IV.

Anterior Vertebral Body Tethering: A Review of the Available Evidence.

Idiopathic scoliosis is a complex three-dimensional deformity of the spine with anterior overgrowth (hypokyphosis), coronal curvature, and axial rotation. Scoliosis treatment in the skeletally immature spine is therapeutically challenging because of growth and was commonly limited to observation, bracing treatment, or fusion. Fusion accomplishes powerful deformity correction at the expense of future growth and mobility of the involved segments, increasing the risk of adjacent segment degeneration and intervertebral disk disease later in life. Anterior vertebral body tethering is a motion-preserving technique that exploits the Hueter-Volkmann principle by applying compression at the anterior and convex aspects of the curve to stimulate differential vertebral growth for gradual deformity reduction without fusion. The appropriate timing, curve magnitude, tensioning, growth prediction, indications, and limitations of tethering are being refined as this technique becomes more prevalent. Early outcome studies show that growth modulation with vertebral body tethering is safe, can achieve good results, and preserve motion in select patients.

Concave and convex growth do not differ over tethered vertebral segments, even with open tri-radiate cartilage.

PURPOSE: To assess the following hypotheses related to vertebral body tethering (VBT): 1. VBT is associated with asymmetric (concave > convex) increases in height over the instrumented vertebra. 2. The instrumented Cobb angle improves following VBT surgery with growth. METHODS: This is a retrospective case series of pediatric patients from a multicenter scoliosis registry treated with VBT between 2013 to 2021. INCLUSION CRITERIA: patients with standing radiographs at < 4 months and ≥ 2 years after surgery. Distances between the superior endplate of the UIV and the inferior endplate of the LIV were measured at the concave corner, mid-point, and convex corner of the endplates. The UIV-LIV angle was recorded. Subgroup analyses included comparing different Risser scores and tri-radiate cartilage (TRC) closed versus open using student t-tests. RESULTS: 83 patients met inclusion criteria (92% female; age at time of surgery 12.5 ± 1.4 years) with mean follow-up time of 3.8 ± 1.4 years. Risser scores at surgery were: 0 (n = 33), 1 (n = 12), 2 (n = 10), 3 (n = 11), 4 (n = 12), and 5 (n = 5). Of the 33 Risser 0 patients, 17 had an open TRC, 16 had a closed TRC. The UIV-LIV distance at concave, middle, and convex points significantly increased from immediate post-op to final-follow-up for Risser 0 patients, but not for Risser 1-5 patients. Increases in UIV-LIV distance were not significantly different between concave, middle, and convex points for all groups. There was no significant improvement or worsening in UIV-LIV angle for any group. CONCLUSION: At a mean of 3.8 years following VBT, 33 Risser 0 patients demonstrated significant growth in the instrumented segment, though there was no difference between concave or convex growth, even for patients with open TRC.

Thoracolumbar curve behavior after selective thoracic anterior vertebral body tethering in Lenke 1A vs Lenke 1C curve patterns.

STUDY DESIGN: Retrospective review of a prospective database. OBJECTIVES: The purpose of this study is to evaluate changes in the thoracic and thoracolumbar/lumbar curves and truncal balance in patients treated with selective thoracic anterior vertebral body tethering (AVBT) with Lenke 1A vs 1C curves at a minimum of 2 years follow-up. Lenke 1C curves treated with selective thoracic AVBT demonstrate equivalent thoracic curve correction and reduced thoracolumbar/lumbar curve correction compared to Lenke 1A curves. Additionally, at the most recent follow-up, both curve types demonstrate comparable coronal alignment at C7 and the lumbar curve apex, though 1C curves have better alignment at the lowest instrumented vertebra (LIV). Rates of revision surgery are equivalent between the two groups. METHODS: A matched cohort of 43 Risser 0-1, Sanders Maturity Scale (SMS) 2-5 AIS pts with Lenke 1A (1A group)and 19 pts with Lenke 1C curves (1C group) treated with selective thoracic AVBT and a minimum of 2-year follow-up were included. Digital radiographic software was used to assess Cobb angle and coronal alignment on preoperative, postoperative and subsequent follow-up radiographs. Coronal alignment was assessed by measuring the distance from the center sacral vertical line (CSVL) to the midpoint of the LIV, apical vertebra for thoracic and lumbar curves and C7. RESULTS: There was no difference in the thoracic curve measured preoperatively, at first erect, pre-rupture or at the most recent follow-up, nor was there a significant difference in C7 alignment (p = 0.057) or apical thoracic alignment (p = 0.272) between the 1A and 1C groups. Thoracolumbar/lumbar curves were smaller in the 1A group at all-time points. However, there was no significant difference between the percent correction between the two groups thoracic (p = 0.453) and thoracolumbar/lumbar (p = 0.105). The Lenke 1C curves had improved coronal translational alignment of the LIV at the most recent follow-up p = 0.0355. At the most recent follow-up the number of patients considered to have successful curve correction (Cobb angle correction of both the thoracic and thoracolumbar//lumbar curves to ≤ 35 degrees), was equivalent between Lenke 1A and Lenke 1C curves (p = 0.80). There was also no difference in the rate of revision surgery between the two groups (p = 0.546). CONCLUSION: This is the first study to compare the impact of lumbar curve modifier type on outcomes in thoracic AVBT. We found that Lenke 1C curves treated with selective thoracic AVBT demonstrate less absolute correction of the thoracolumbar/lumbar curve at all time points but have equivalent percent correction of the thoracic and thoracolumbar/lumbar curves. The two groups have equivalent alignment at C7 and the thoracic curve apex, and Lenke 1C curves have better alignment at the LIV at the most recent follow-up. Furthermore, they have an equivalent rate of revision surgery compared to Lenke 1A curves. Selective thoracic AVBT is a viable option for selective Lenke 1C curves, but despite equivalent correction of the thoracic curve, there is less correction of the thoracolumbar/lumbar curve at all-time points.

Surgical Outcomes of Cerebral Palsy Patients With Scoliosis and Lumbar Hyperlordosis: A Comparative Analysis With 2-year Minimum Follow-up.

STUDY DESIGN: Retrospective review of a prospectively collected multicenter database. OBJECTIVE: To compare outcomes of patients with cerebral palsy (CP) who undergo surgery for scoliosis with normal lordosis (NL) versus hyperlordosis. SUMMARY OF BACKGROUND DATA: Surgical correction of scoliosis with lumbar hyperlordosis is challenging. Hyperlordosis may confer higher perioperative morbidity, but this is not well understood. MATERIALS AND METHODS: A multicenter database was queried for CP patients who underwent surgery from 2008 to 2017. The minimum follow-up was 2 years. Two groups were identified: lumbar lordosis <75° (NL) versus ≥ 75° hyperlordosis (HL). Perioperative, radiographic, and clinical outcomes were compared. RESULTS: Two hundred seventy-five patients were studied: 236 NL and 39 HL (-75 to -125°). The mean age was 14.1 years, and 52.4% were male. Patients with hyperlordosis had less cognitive impairment (76.9% vs. 94.0%, P =0.008) and higher CPCHILD scores (59.4 vs. 51.0, P =0.003). Other demographics were similar between the groups. Patients with hyperlordosis had greater lumbar lordosis (-90.5 vs. -31.5°, P <0.001) and smaller sagittal vertical axis (-4.0 vs. 2.6 cm, P <0.001). Patients with hyperlordosis had greater estimated blood loss (2222.0 vs. 1460.7 mL, P <0.001) but a similar perioperative complication rate (20.5% vs. 22.5%, P =0.787). Significant correction of all radiographic parameters was achieved in both groups. The HL group had postoperative lumbar lordosis of -68.2° and sagittal vertical axis of -1.0 cm. At a 2-year follow-up, patients with hyperlordosis continued to have higher CPCHILD scores and gained the greatest benefit in overall quality of life measures (20.0 vs. 6.1, P =0.008). The reoperation rate was 10.2%: implant failure (3.6%), pseudarthrosis (0.7%), and wound complications (7.3%). There were no differences in the reoperation rate between the groups. CONCLUSION: Surgical correction of scoliosis with hyperlordosis is associated with greater estimated blood loss but similar radiographic results, perioperative morbidity, and reoperation rate as normal lordosis. Patients with hyperlordosis gained greater overall health benefits. Correction of ≥25% of hyperlordosis seems satisfactory. LEVEL OF EVIDENCE: 3.

Posterior cervical spinal fusion in the pediatric population using modern adult instrumentation - clinical outcome and safety.

PURPOSE: Traditionally, less rigid fixation techniques have been applied to the pediatric cervical spine. There is a lack of long-term outcome data for rigid fixation techniques. The purpose of this study was to define the clinical outcome and safety of posterior instrumented fusion in the pediatric population using adult posterior instrumentation. METHODS: A multicenter, retrospective review of pediatric patients who underwent posterior cervical fusion using a 3.5 mm posterior cervical system for any indication was performed. Outcome parameters included complications, revision and fusion rates, operative time (OR), blood loss, and postoperative neurologic status. Outcomes were compared between patient groups (posterior only versus anterior/posterior approach, short versus intermediate versus long fusion, and between different etiologies) using Mann-Whitney and chi-square test. RESULTS: Seventy-nine patients with a mean age of 9.9 years and mean follow-up of 2.8 years were included. At baseline 44 (56%) had an abnormal neurologic exam. Congenital deformities and basilar invagination were the most common indications for surgery. Posterior-only surgery was performed in 71 (90%) cases; mean number of levels fused was 4 (range 1-15). Overall, 4 (5%) operative complications and 4 (5%) revisions were reported at an average postoperative time of 2.6 years. Neurologic status remained unchanged in 74%, improved in 23%, and worsened in 3%. When comparing outcome measures between the various groups, 2 significant differences were found: OR was longer in the anterior/posterior approach group and decline of neuro status was more frequent in the long fusion group. CONCLUSION: Posterior cervical fusion with an adult 3.5 mm posterior cervical system was safe in this cohort of 79 pediatric patients irrespective of surgical technique, fusion length, and etiology, resulting in a high fusion and low complication/revision rate.

Vertebral body tethering for non-idiopathic scoliosis: initial results from a multicenter retrospective study.

PURPOSE: Vertebral body tethering (VBT) has been described for patients with idiopathic scoliosis. Results of the technique for non-idiopathic scoliosis have not yet been reported. METHODS: An international multicenter registry was retrospectively queried for non-idiopathic scoliosis patients who underwent VBT with minimum 2-year follow-up. Success at 2 years was defined as Cobb angle < 35 degrees and no fusion surgery. RESULTS: Of the 251 patients treated with VBT, 20 had non-idiopathic scoliosis and minimum 2-year follow-up. Mean age at surgery was 12.4 years (range 10 to 17 years). Mean major Cobb angle at enrollment was 56 degrees. Of those, 18 patients had a major thoracic curve and two had a major lumbar curve. Of the 20 patients, nine met criteria for success (45%). Eight of the 20 patients had poor outcomes (four fusions, four with curve > 50 degrees). Success was associated with smaller preoperative Cobb angle (50 vs. 62 degrees, p = 0.01) and smaller Cobb angle on initial postop imaging (28 degrees vs. 46 degrees, p = 0.0007). All patients with Cobb angle < 35 degrees on 1st postop imaging had a successful result, with the exception of one patient who overcorrected and required fusion. Syndromic vs. neuromuscular patients had a higher likelihood of success (5 of 7, 71%, 2 of 10, 20%, p = 0.03). CONCLUSION: Selected non-idiopathic scoliosis can be successfully treated with VBT, but failure rates are high and were associated with large curves, inadequate intraoperative correction and neuromuscular diagnosis. Achieving a Cobb angle less than 35 degrees on 1st standing radiograph was associated with a successful outcome which was achieved in 45% of patients. LEVEL OF EVIDENCE: Level IV (retrospective review study).

Operative differences for posterior spinal fusion after vertebral body tethering: Are we fusing more levels in the end?

PURPOSE: Little is known about the perioperative characteristics associated with a posterior spinal fusion (PSF) in adolescent idiopathic scoliosis patients previously treated with vertebral body tethering (VBT). We aimed to determine if operative time, estimated blood loss, postoperative length of stay, instrumentation type, and implant density differed in patients that received a PSF (i.e., PSF-Only) or a PSF following a failed VBT (i.e., PSF-VBT). METHODS: We retrospectively assessed matched cohort data (PSF-VBT = 22; PSF-Only = 22) from two multi-center registries. We obtained: (1) operative time, (2) estimated blood loss, (3) postoperative length of stay, (4) instrumentation type, and (5) implant density. Theoretical fusion levels prior to the index procedure were obtained for PSF-VBT and compared to the actual levels fused. RESULTS: We observed no difference in operative time, estimated blood loss, or postoperative length of stay. Instrumentation type was all-screw in PSF-Only and varied in PSF-VBT with nearly 25% of patients exhibiting a hybrid construct. There was no added benefit to removing anterior instrumentation prior to fusion; however, implant density was higher in PSF-Only (1.9 ± 0.2) than when compared to PSF-VBT (1.7 ± 0.3). An additional two levels were fused in 50% of PSF-VBT patients, most of which were added to the distal end of the construct. CONCLUSIONS: We found that operative time, estimated blood loss, and postoperative length of stay were similar in both cohorts; however, the length of the fusion construct in PSF-VBT is likely to be two levels longer when a failed VBT is converted to a PSF.

Drain options after vertebral body tethering.

PURPOSE: Since the introduction of vertebral body tethering (VBT) for adolescent idiopathic scoliosis (AIS), a variety of post-operative chest drainage systems have been utilized. Most surgeons use formal chest tubes with a Pleur-evac, while others use smaller bulb suction drains (e.g., Blake drain). In addition, some centers utilize pleural closure. This multicenter study evaluates whether drain type or pleural closure impact perioperative and 90 day complication rates. METHODS: A retrospective review was conducted from three institutions with established VBT programs. All preoperative, perioperative and 90 day postoperative data were analyzed to determine differences in outcomes between three cohorts: standard chest tube (SCT), standard chest tube with pleural closure (SCTPC) and 10 French Bulb drain (BD). RESULTS: 104 patients were identified for the study. 57 SCT, 25 SCTPC and 22 BD. All data are listed in order: SCT, SCTPC, BD. Length of stay (3.7, 4.3, 3.0 days) was less in the BD group (p = 0.009); post-operative drainage (460, 761, 485 cc) was less in the SCT and BD groups (p < 0.001); intra-operative estimated blood loss (EBL) 146, 382, 64 cc was less in the BD group (p < 0.001). No significant difference in number of days (3.2, 3.2, and 2.8 days) drainage was in place, groups (p = 0.311). Complication profile was similar with 2 chest tube reinsertions in the SCT and one hemothorax that resolved spontaneously in BD group. CONCLUSIONS: In this series of 104 patients, SCT, SCTPC and BD all had a similar safety profile. All three methods were safe and effective in managing post-operative chest drainage after thoracic VBT. In the series, BD group had significantly shorter LOS than both groups that used chest tubes. LEVEL OF EVIDENCE: Level III, Retrospective cohort study.

Reliability of radiographic assessment of growth modulation from anterior vertebral body tethering surgery in pediatric scoliosis.

PURPOSE: To assess the reliability of vertebral height and angular measurements for anterior vertebral body tethering (AVBT). METHODS: Eight observers measured PA radiographs of 15 idiopathic scoliosis patients treated with AVBT, pre-operative and 4-year follow-up. Vertebral wedging, disc wedging, convex vertebral body heights, and concave vertebral body heights of the 3 apical vertebrae were measured. For each observer, there were a total of 90 measurements for vertebral body height and 75 measurements for all wedging types At least 14 days elapsed between first and second round measurements. RESULTS: From the pre-operative to the 4-year follow-up time-point, the total wedging angle over the 3 peri-apical levels fell from 30 ± 7° to 16 ± 6° (p < 0.001) and the difference between the convex and concave vertebral heights decreased from 9 ± 4 to 6 ± 3 mm (p < 0.001). Interobserver agreement for pre-operative vertebral body heights was good [ICC = 0.80; 95% CI (0.74-0.85)]. At 4-year follow-up there was a moderate agreement [ICC = 0.67 (0.59-0.74)]. There was a poor interobserver agreement for pre-operative wedging angle measurements [ICC = 0.41 (0.32-0.52)] and 4-year follow-up [ICC = 0.45 (0.36-0.56)]. The Limits of Agreement with the Mean (LOAM) for pre-op heights was ± 2.4 mm, similar to the follow-up ± 2.6 mm. When raters are averaged in random groups of two the agreement limits decrease to ± 1.8 mm pre-op and ± 1.6 mm at follow-up. Similarly for wedging angles, LOAM values among the 8 observers of ± 4.6° pre-op and ± 4.2° dropped to ± 2.7° for both pre-op and follow-up when random groups of two raters were averaged together. Intraobserver agreement ranged from good to excellent per individual (ICC = 0.84-0.94) for pre-operative vertebral body heights, but this decreased at 4-year follow-up (ICC = 0.52-0.88). Intraobserver agreement was low overall for wedging (pre-operative ICC = 0.41-0.71; 4-year follow-up ICC = 0.41-0.76). CONCLUSION: Based on 8 individual observers, interobserver agreement ranged from good (pre-operative vertebral body heights) to moderate (4-year follow-up vertebral body heights) to poor (all wedging angles). To improve the reliability of the measurement of wedging angles, we recommend averaging the measurements of at least two observers.

Best Practice Guidelines for Surgical Site Infection in High-risk Pediatric Spine Surgery: Definition, Prevention, Diagnosis, and Treatment.

BACKGROUND: Prior "best practice guidelines" (BPG) have identified strategies to reduce the risk of acute deep surgical site infection (SSI), but there still exists large variability in practice. Further, there is still no consensus on which patients are "high risk" for SSI and how SSI should be diagnosed or treated in pediatric spine surgery. We sought to develop an updated, consensus-based BPG informed by available literature and expert opinion on defining high-SSI risk in pediatric spine surgery and on prevention, diagnosis, and treatment of SSI in this high-risk population. MATERIALS AND METHODS: After a systematic review of the literature, an expert panel of 21 pediatric spine surgeons was selected from the Harms Study Group based on extensive experience in the field of pediatric spine surgery. Using the Delphi process and iterative survey rounds, the expert panel was surveyed for current practices, presented with the systematic review, given the opportunity to voice opinions through a live discussion session and asked to vote regarding preferences privately. Two survey rounds were conducted electronically, after which a live conference was held to present and discuss results. A final electronic survey was then conducted for final voting. Agreement ≥70% was considered consensus. Items near consensus were revised if feasible to achieve consensus in subsequent surveys. RESULTS: Consensus was reached for 17 items for defining high-SSI risk, 17 items for preventing, 6 for diagnosing, and 9 for treating SSI in this high-risk population. After final voting, all 21 experts agreed to the publication and implementation of these items in their practice. CONCLUSIONS: We present a set of updated consensus-based BPGs for defining high-risk and preventing, diagnosing, and treating SSI in high-risk pediatric spine surgery. We believe that this BPG can limit variability in practice and decrease the incidence of SSI in pediatric spine surgery. LEVEL OF EVIDENCE: Not applicable.

Spontaneous Lumbar Curve Correction Following Vertebral Body Tethering of Main Thoracic Curves.

BACKGROUND: Growth modulation through anterior vertebral body tethering (AVBT) has emerged as a fusionless option for the treatment of progressive scoliosis. When tethering the main thoracic curve, the compensatory thoracolumbar/lumbar curve must correct indirectly as a result. The present study evaluated the response of these lumbar curves following AVBT of the main thoracic curves. METHODS: Patients who underwent thoracic AVBT and who had a minimum follow-up of 2 years were included. Magnitudes of the thoracic and lumbar curves were recorded preoperatively and at the first-erect and 2-year postoperative visits. Lumbar curves were further stratified according to their lumbar modifier (A, B, or C). Analysis of variance (ANOVA) and repeated-measures ANOVA were performed to compare correction rates, and the Pearson coefficient was utilized to determine the correlation between the tethered thoracic curve and uninstrumented lumbar curve magnitudes. RESULTS: A total of 218 patients were included. Thoracic curve correction was 40% at the first-erect visit and 43% at 2 years (p = 0.012). Lumbar correction was 30%, 26%, and 18% at the first-erect visit (p < 0.001 for all compared with preoperatively) and minimally changed at 31%, 26%, and 24% at 2 years for lumbar modifiers A, B, and C, respectively. A total of 118 patients (54%) showed thoracic curve improvement between the first-erect and 2-year visits. In a subgroup analysis, these patients had a correction in lumbar curve magnitude from preoperatively to the first-erect visit of 30%, 22%, and 16% for lumbar modifiers A, B, C, respectively, that increased to 42%, 34%, and 31% at 2 years, with strong correlation to thoracic correction at 2-year follow-up (r = 0.557, p < 0.001). CONCLUSIONS: Although there was immediate lumbar correction following AVBT of a main thoracic curve, further improvement following initial correction was only observed among patients with growth modulation of the thoracic curve. Considering all patients, the uninstrumented lumbar curve corrected 30% at 2 years and the instrumented thoracic curve corrected 40%. As indications for AVBT are refined, these data will provide insight into the response of the uninstrumented lumbar curve. LEVEL OF EVIDENCE: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.