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.

Risk Factors for Progression of Cervical Congenital Scoliosis and Associated Compensatory Curve Behavior.

Background: This study investigated risk factors for progression of deformity in pediatric congenital cervical scoliosis (CCS) and evaluated the correlation between congenital cervical curves and compensatory thoracic and lumbar curves. Methods: Medical records were retrospectively reviewed for 38 pediatric patients with CCS with a minimum 2-year follow-up. Curve progression was defined as >10° increase in cervical coronal curve angle between presentation and last follow-up. Results: A total of 38 patients (16 girls, 22 boys) with a mean age at presentation of 5.6 ± 4.1 years met the inclusion criteria. Sixteen patients (42%) had curve progression with a mean follow-up of 3.1 ± 3.0 years. At presentation, T1 slope was significantly larger among children with progressive deformities (p = 0.041). A total of 18 of the 38 patients with strictly cervical spine deformity were then selected for subanalysis to evaluate the progression of compensatory curves. Cervical major coronal curves were found to significantly correlate with lumbar major coronal curves (r = 0.409), C2 central sacral vertical line (CSVL) (r = 0.407), and C7-CSVL (r = 0.403) (p < 0.05). Thoracic major coronal curves did not significantly correlate with cervical major coronal curves (r = 0.218) (p > 0.05). Conclusion: In conclusion, 42% of osseous CCS curves progressed over time in the overall cohort, and high initial T1 slope was found to be most highly correlated with progression of cervical deformity. Cervical major coronal curves significantly correlated with lumbar curve magnitude but not with thoracic curve size in isolated CCS, possibly due to the increased flexibility of the lumbar spine which may allow greater compensatory balance and thus have a greater correlation with cervical curve magnitude and possibly progression.

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.

Lumbar Vertebral Body Tethering: Single Center Outcomes and Reoperations in a Consecutive Series of 106 Patients.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To evaluate the outcomes and reoperation rates in patients with adolescent idiopathic scoliosis (AIS) undergoing lumbar anterior vertebral body tethering (AVBT). SUMMARY OF BACKGROUND DATA: Anterior vertebral body tethering (AVBT) is a viable option in growing children. The benefit of motion preservation must be balanced by a higher reoperation rate. A paucity of reports has addressed lumbar AVBT. METHODS: A single-center retrospective study was conducted to identify all patients who underwent lumbar AVBT (lowest instrumented vertebra L3 or L4) with a minimum 2 years of follow-up. Clinical and radiographic parameters, including complications and reoperations, were also collected. Statistical analysis was performed using Student's t-test for qualitative variables. RESULTS: From a dataset of 551 patients, we identified 106 patients (89% female) who underwent a lumbar AVBT (33 lumbar only, 73 bilateral thoracic/lumbar) with mean follow-up of 4.1±1.6 years at which point 85% (90/106) had reached skeletal maturity. Preoperatively, these patients were skeletally immature (age: 12.8±1.3 y, Sanders: 3.3±0.8, R=0.6±0.9) with a lumbar coronal curve angle of 49.6°±11.2 which corrected to 19.9°±11.2 (P <0.0001) at most recent follow-up. At the latest follow-up, 76.4% (81/106) of the patients harbored a coronal curve angle of < 30°. Twenty patients (18.9%) underwent 23 reoperations, with overcorrection being the most common (10/23, 43%). Broken tethers led to reoperation in 3 instances (3/23, 13%). Six patients in the cohort needed a posterior spinal fusion (6/106, 5.4%). CONCLUSIONS: Vertebral body tethering is a viable treatment option for skeletally immature patients with idiopathic scoliosis. This report is the largest to date for lumbar AVBT, highlighting that 84% of patients harbored a curve < 35° at the latest follow-up but with an 18.9% reoperation rate. LEVEL OF EVIDENCE: 3.

The Impact of Anterior Vertebral Body Tethering on Pulmonary Function.

STUDY DESIGN: Retrospective, single-center study. OBJECTIVE: To examine pulmonary function tests (PFTs) in patients undergoing anterior vertebral body tethering (AVBT). SUMMARY OF BACKGROUND DATA: The effect of AVBT on pulmonary status remains unclear. MATERIALS AND METHODS: The authors examined preoperative and postoperative PFTs following AVBT in a retrospective, single-center cohort of patients. Outcomes were compared using percent predicted values as continuous and categorical variables (using 10% change as significant) and divided into categorical values based on the American Thoracic Society standards. RESULTS: Fifty-eight patients with adolescent idiopathic scoliosis were included, with a mean age of 12.5±1.4 years and a follow-up of 4.2±1.1 years. The mean thoracic curve was 47°±9°, which improved to 21°±12°. At baseline, the mean forced expiratory volume in one second (FEV1%) and forced vital capacity (FVC%) values were 79% and 82%, respectively. Four patients had normal FEV1% (≥100%), 67% had mild restrictive disease (70%-99%) and the rest had worse FEV1%. Mean FEV1 improved from 2.2 to 2.6 L ( P <0.05) and FVC improved from 2.5 to 3.0 L ( P <0.05); however, % predicted values remained unchanged (FEV1%: 79%-80%; FVC%: 82-80%, P >0.05) with mean postoperative PFTs at 37±12 months postoperative. The use of miniopen thoracotomy was not associated with worsening PFTs, but extension of the lowest instrumented vertebra below T12 was correlated with decreasing FEV1% in the bivariate analysis ( P <0.05). Patients with worse preoperative FVC% (80±13% vs. 90±11%, P =0.03) and FEV1% (77±17% vs. 87±12%, P =0.06) also had a greater likelihood of declining postoperative FEV1%. CONCLUSION: Pulmonary function in most patients undergoing AVBT remained stable (76%) or improved (14%); however, a subset may worsen (10%). Further studies are needed to identify the risk factors for this group, but worse preoperative PFTs and extension below T12 may be risk factors for worsening pulmonary function.

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.

Early outcomes in hybrid fixation for idiopathic scoliosis: posterior fusion combined with anterior vertebral body tethering. Patient series.

BACKGROUND: Anterior vertebral body tethering (AVBT) and posterior spinal fusion (PSF) are options for patients with idiopathic scoliosis. Combining both procedures in patients with double curves, a procedure in which PSF is performed for the thoracic curve and AVBT for the lumbar curve, provides maximal correction of the thoracic curve with a theoretical maintenance of motion in the lumbar spine. OBSERVATIONS: The authors retrospectively reviewed 20 skeletally immature patients diagnosed with idiopathic scoliosis at a single institution with an average age of 12.7 ± 1.6 years and who had undergone hybrid treatment with an average follow-up of 8 months. The PSF procedures averaged 276 ± 63 minutes with 442.8 ± 295 mL of blood loss, and the AVBT averaged 275 ± 54 minutes with 118.3 ± 80 mL of blood loss. Following the hybrid correction, the thoracic and lumbar coronal curve angles improved from 67.6° to 21.6° and from 65.2° to 24°, respectively. The three-dimensional kyphosis improved from 3.3° to 24°. LESSONS: A combined approach of PSF and AVBT is safe and effective for idiopathic scoliosis. This approach combines the gold standard of thoracic fusion with the motion preservation benefits of AVBT in the lumbar spine. This study will continue to refine indications for AVBT.

Pain After Anterior Vertebral Body Tethering: Incidence, Risk Factors, and Timing.

STUDY DESIGN: Retrospective case series. OBJECTIVE: To examine the incidence and risk factors for postoperative pain following anterior vertebral body tethering (AVBT) for adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: Up to 78% of patients with AIS report preoperative pain; it is the greatest patient concern surrounding surgery. Pain significantly decreases following posterior spinal fusion, but pain following AVBT is poorly understood. MATERIALS AND METHODS: We retrospectively reviewed 279 patients with a two-year follow-up after AVBT for AIS. We collected demographic, radiographic, and clinical data pertinent to postoperative pain at each time interval of preoperative and postoperative visits (6 wk, 6 mo, 1 y, and annually thereafter). RESULTS: Within our cohort, 68.1% of patients reported preoperative pain. Older age ( P =0.014) and greater proximal thoracic ( P =0.013) and main thoracic ( P =0.002) coronal curve magnitudes were associated with preoperative pain. Pain at any time point > 6 weeks postoperatively was reported in 41.6% of patients; it was associated with the female sex ( P =0.032), need for revision surgery ( P =0.019), and greater lateral displacement of the apical lumbar vertebrae ( P =0.028). The association between preoperative and postoperative pain trended toward significance ( P =0.07). At 6 months postoperatively, 91.8% had pain resolution; the same number remained pain-free at the time of last follow-up. The presence of a postoperative complication was associated with new-onset postoperative pain that resolved ( P =0.009). Only 8.2% had persistent pain, although no risk factors were found to be associated with persistent pain. CONCLUSION: In our cohort of 279 patients with a minimum 2-year follow-up after AVBT, 68.1% reported preoperative pain. Nearly 42% reported postoperative pain at any time point, but only 8.2% had persistent pain. Postoperative pain after AVBT was associated with female sex, revision surgery, and Lenke lumbar modifier. AVBT is associated with a significant reduction in pain, and few patients report long-term postoperative pain.

COL11A2 as a candidate gene for vertebral malformations and congenital scoliosis.

Human vertebral malformations (VMs) have an estimated incidence of 1/2000 and are associated with significant health problems including congenital scoliosis (CS) and recurrent organ system malformation syndromes such as VACTERL (vertebral anomalies; anal abnormalities; cardiac abnormalities; tracheo-esophageal fistula; renal anomalies; limb anomalies). The genetic cause for the vast majority of VMs are unknown. In a CS/VM patient cohort, three COL11A2 variants (R130W, R1407L and R1413H) were identified in two patients with cervical VM. A third patient with a T9 hemivertebra and the R130W variant was identified from a separate study. These substitutions are predicted to be damaging to protein function, and R130 and R1407 residues are conserved in zebrafish Col11a2. To determine the role for COL11A2 in vertebral development, CRISPR/Cas9 was used to create a nonsense mutation (col11a2L642*) as well as a full gene locus deletion (col11a2del) in zebrafish. Both col11a2L642*/L642* and col11a2del/del mutant zebrafish exhibit vertebral fusions in the caudal spine, which form due to mineralization across intervertebral segments. To determine the functional consequence of VM-associated variants, we assayed their ability to suppress col11a2del VM phenotypes following transgenic expression within the developing spine. While wildtype col11a2 expression suppresses fusions in col11a2del/+ and col11a2del/del backgrounds, patient missense variant-bearing col11a2 failed to rescue the loss-of-function phenotype in these animals. These results highlight an essential role for COL11A2 in vertebral development and support a pathogenic role for two missense variants in CS.

Consensus-Based Best Practice Guidelines for the Management of Spinal Deformity and Associated Tumors in Pediatric Neurofibromatosis Type 1: Screening and Surveillance, Surgical Intervention, and Medical Therapy.

BACKGROUND: Spinal conditions, such as scoliosis and spinal tumors, are prevalent in neurofibromatosis type 1 (NF1). Despite the recognized importance of their early detection and treatment, there remain knowledge gaps in how to approach these manifestations. The purpose of this study was to utilize the experience of a multidisciplinary committee of experts to establish consensus-based best practice guidelines (BPGs) for spinal screening and surveillance, surgical intervention, and medical therapy in pediatric patients with NF1. METHODS: Using the results of a prior systematic review, 10 key questions that required further assessment were first identified. A committee of 20 experts across medical specialties was then chosen based on their clinical experience with spinal deformity and tumors in NF1. These were 9 orthopaedic surgeons, 4 neuro-oncologists/oncologists, 3 neurosurgeons, 2 neurologists, 1 pulmonologist, and 1 clinical geneticist. An initial online survey on current practices and opinions was conducted, followed by 2 additional surveys via a formal consensus-based modified Delphi method. The final survey involved voting on agreement or disagreement with 35 recommendations. Items reaching consensus (≥70% agreement or disagreement) were included in the final BPGs. RESULTS: Consensus was reached for 30 total recommendations on the management of spinal deformity and tumors in NF1. These were 11 recommendations on screening and surveillance, 16 on surgical intervention, and 3 on medical therapy. Five recommendations did not achieve consensus and were excluded from the BPGs. CONCLUSION: We present a set of consensus-based BPGs comprised of 30 recommendations for spinal screening and surveillance, surgical intervention, and medical therapy in pediatric NF1.

What Happens After a Vertebral Body Tether Break? Incidence, Location, and Progression With Five-year Follow-up.

STUDY DESIGN: Retrospective review. OBJECTIVE: To study risk factors for anterior vertebral body tether (VBT) breakage. SUMMARY OF BACKGROUND DATA: VBT is used to treat adolescent idiopathic scoliosis in skeletally immature patients. However, tethers break in up to 48% of cases. MATERIALS AND METHODS: We reviewed 63 patients who underwent thoracic and/or lumbar VBT with a minimum five-year follow-up. We radiographically characterized suspected tether breaks as a change in interscrew angle >5°. Demographic, radiographic, and clinical risk factors for presumed VBT breaks were evaluated. RESULTS: In confirmed VBT breaks, the average interscrew angle change was 8.1°, and segmental coronal curve change was 13.6°, with a high correlation ( r =0.82). Our presumed VBT break cohort constituted 50 thoracic tethers, four lumbar tethers, and nine combined thoracic/lumbar tethers; the average age was 12.1±1.2 years and the mean follow-up was 73.1±11.7 months. Of 59 patients with thoracic VBTs, 12 patients (20.3%) had a total of 18 breaks. Eleven thoracic breaks (61.1%) occurred between two and five years postoperatively, and 15 (83.3%) occurred below the curve apex ( P <0.05). The timing of thoracic VBT breakage moderately correlated with more distal breaks ( r =0.35). Of 13 patients who underwent lumbar VBT, eight patients (61.5%) had a total of 12 presumed breaks. Six lumbar breaks (50%) occurred between one and two years postoperatively, and seven (58.3%) occurred at or distal to the apex. Age, sex, body mass index, Risser score, and curve flexibility were not associated with VBT breaks, but the association between percent curve correction and thoracic VBT breakage trended toward significance ( P =0.054). Lumbar VBTs were more likely to break than thoracic VBTs ( P =0.016). Seven of the patients with presumed VBT breaks (35%) underwent revision surgery. CONCLUSIONS: Lumbar VBTs broke with greater frequency than thoracic VBTs, and VBT breaks typically occurred at levels distal to the curve apex. Only 15% of all patients required revision. LEVEL OF EVIDENCE: 3.

Building consensus for the medical management of children with moderate and severe acute spinal cord injury: a modified Delphi study.

OBJECTIVE: The focus of this modified Delphi study was to investigate and build consensus regarding the medical management of children with moderate and severe acute spinal cord injury (SCI) during their initial inpatient hospitalization. This impetus for the study was based on the AANS/CNS guidelines for pediatric SCI published in 2013, which indicated that there was no consensus provided in the literature describing the medical management of pediatric patients with SCIs. METHODS: An international, multidisciplinary group of 19 physicians, including pediatric neurosurgeons, orthopedic surgeons, and intensivists, were asked to participate. The authors chose to include both complete and incomplete injuries with traumatic as well as iatrogenic etiologies (e.g., spinal deformity surgery, spinal traction, intradural spinal surgery, etc.) due to the overall low incidence of pediatric SCI, potentially similar pathophysiology, and scarce literature exploring whether different etiologies of SCI should be managed differently. An initial survey of current practices was administered, and based on the responses, a follow-up survey of potential consensus statements was distributed. Consensus was defined as ≥ 80% of participants reaching agreement on a 4-point Likert scale (strongly agree, agree, disagree, strongly disagree). A final meeting was held virtually to generate final consensus statements. RESULTS: Following the final Delphi round, 35 statements reached consensus after modification and consolidation of previous statements. Statements were categorized into the following eight sections: inpatient care unit, spinal immobilization, pharmacological management, cardiopulmonary management, venous thromboembolism prophylaxis, genitourinary management, gastrointestinal/nutritional management, and pressure ulcer prophylaxis. All participants stated that they would be willing or somewhat willing to change their practices based on consensus guidelines. CONCLUSIONS: General management strategies were similar for both iatrogenic (e.g., spinal deformity, traction, etc.) and traumatic SCIs. Steroids were recommended only for injury after intradural surgery, not after acute traumatic or iatrogenic extradural surgery. Consensus was reached that mean arterial pressure ranges are preferred for blood pressure targets following SCI, with goals between 80 and 90 mm Hg for children at least 6 years of age. Further multicenter study of steroid use following acute neuromonitoring changes was recommended.

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.

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.

Trunk Range of Motion and Patient Outcomes After Anterior Vertebral Body Tethering Versus Posterior Spinal Fusion: Comparison Using Computerized 3D Motion Capture Technology.

BACKGROUND: Anterior vertebral body tethering (AVBT) for adolescent idiopathic scoliosis (AIS) is postulated to preserve motion compared with traditional posterior spinal fusion (PSF), but few studies exist to date. We used a validated computerized 3D model to compare trunk motion between patients treated with PSF and AVBT, and analyzed trunk motion in relation to the lowest instrumented vertebra (LIV). METHODS: This was a single-center retrospective review of a consecutive series of skeletally immature patients with AIS who underwent motion analysis prior to PSF (n = 47) or AVBT (n = 65) and 2 years postoperatively. Patients were divided into 4 groups on the basis of the LIV (≤L1, L2, L3, L4). Computerized 3D kinematic evaluations included thoracic and lumbar flexion, extension, side-bending, and rotation. Patient outcomes were assessed using the Scoliosis Research Society (SRS)-22 questionnaire. RESULTS: The LIV was ≤L1 in 48 patients treated with AVBT and 23 treated with PSF, L2 in 4 AVBT and 8 PSF patients, L3 in 10 AVBT and 8 PSF patients, and L4 in 3 AVBT and 8 PSF patients. PSF patients had a significant loss of motion in all 4 directions at 2 years postoperatively (e.g., flexion loss was 11° for ≤L1 to 30° for L4; p < 0.001). This equated to a 7° loss of trunk flexion per additional LIV level included in the fusion. AVBT patients only demonstrated loss of flexion and side-bending at 2 years postoperatively (e.g., flexion loss of 11° for L1 to 17° for L4; p < 0.001). Preoperative curve size and flexibility did not have any significant impact on differences in trunk motion between AVBT and PSF. SRS-22 scores were predominantly similar for AVBT versus PSF preoperatively and at 2 years postoperatively. CONCLUSIONS: Patients treated with AVBT experienced predominantly less motion loss compared with PSF patients at 2 years postoperatively. Patients treated with PSF demonstrated loss of motion in all planes that increased with each additional LIV from ≤L1 to L4, with 7° loss of flexion per additional LIV. However, the differences in total trunk motions were relatively modest for PSF and AVBT with an LIV of ≤L1. Preoperative curve magnitude and flexibility had no significant impact on trunk motion in either group. SRS-22 scores were similar for both groups at 2 years postoperatively. LEVEL OF EVIDENCE: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Do drains help reduce the risk of complications after thoracoplasties in posterior spinal fusions for adolescent idiopathic scoliosis?

PURPOSE: In adolescent idiopathic scoliosis (AIS), the rib prominence is a major cosmetic concern which can be improved using thoracoplasties. We sought to determine if the use of deep drains helps minimize the development of pleural effusions after thoracoplasties. METHODS: Retrospective study of 45 patients with AIS undergoing posterior spinal fusion (PSF) and thoracoplasties. RESULTS: Thirty six out of 45 patients (80.0%) required placement of a deep surgical drain, and 16 out of 45 (35.6%) developed pleural effusions after PSF with concomitant thoracoplasty. Of the 16 patients who developed pleural effusion, 12 of 36 (33.3%) required a placement of a deep drain (p > 0.05). Of the total 45 patients in this cohort, 3 patients (6.7%) required chest tubes, and 4 patients (8.9%) developed surgical site infections (SSIs). We found that deep drains were associated with a lower incidence of SSI (2.8% vs 33.3%; p = 0.021). Patients who had a pleural effusion had longer ICU stays (p = 0.037) and longer requirements of nasal oxygen (p = 0.025). DISCUSSION: The presence of a pleural effusion in patients with AIS undergoing PSF with thoracoplasty was associated with longer oxygen requirements and length of hospital ICU admission. Thirty six percent of patients with thoracoplasties developed pleural effusions, but deep subfascial drains did not significantly decrease the incidence of pleural effusions.

How low can you go? Implant density in posterior spinal fusion converted from growing constructs for early onset scoliosis.

STUDY DESIGN: Retrospective, multicenter comparative. OBJECTIVES: Our purpose was to compare early onset scoliosis (EOS) patients treated with ultra-low, low, and high implant density constructs when undergoing conversion to definitive fusion. Larson et al. demonstrated that implant density (ID) at fusion does not correlate with outcomes in the treatment of adolescent idiopathic scoliosis, but did not address growth-friendly graduates. METHODS: EOS patients treated with growth-friendly constructs converted to fusion between 2000 and 2017 were reviewed from a multicenter database. ID was defined as number of pedicle screws, hooks, and sublaminar/bands per level fused. Patients were divided into ultra-low ID (< 1.3), low (≥ 1.3 and < 1.6), and high ID (≥ 1.6). EXCLUSION CRITERIA: < 2 years follow-up from fusion or inadequate radiographs. RESULTS: A total of 152 patients met inclusion criteria with 39 (26%) patients in the high ID group, 33 (22%) patients in the low ID group, and 80 (52%) in the ultra-low ID group. Groups were similar in operative time (p = 0.61), pre-fusion major curve (p = 0.71), mean number of levels fused (p = 0.58), clinical follow-up (p = 0.30), and radiographic follow-up (p = 0.90). Patients in the low ID group (11.6 ± 1.5 years) were slightly younger at the time of definitive fusion than patients in the ultra-low ID group (12.9 ± 2.2 years) and high ID group (12.5 ± 1.7 years) (p = 0.009). There was significantly more blood loss in the high ID group than the other two groups (high ID: 946.8 ± 606.0 mL vs. low ID: 733.9 ± 434.5 mL and ultra-low ID: 617.4 ± 517.2 mL; p = 0.01), but there was no significant difference with regard to percent of total blood volume lost (high ID: 59.3 ± 48.7% vs. low ID: 54.5 ± 37.5% vs. ultra-low ID: 51.7 ± 54.9%; p = 0.78). There was a difference in initial improvement in major curve between the groups (high ID: 21.6° vs. low ID: 18.0° vs. ultra-low ID: 12.6°; p = 0.01). However, during post-fusion follow-up, correction decreased 7.1° in the high ID group, 2.6 in the low ID group, and 2.8 in the ultra-low ID group (p = 0.19). At final follow-up, major curve correction from pre-fusion was similar between groups (high ID: 14.5° vs. low ID: 15.5° vs. ultra-low ID: 9.7°, p = 0.14). At final follow-up, there was no difference in T1-T12 length gain (p = 0.85), T1-S1 length gain (p = 0.68), coronal balance (p = 0.56), or sagittal balance (p = 0.71). The revision rate was significantly higher in the ultra-low ID group (13.8%; 11/80) versus the high ID group (2/39; 5.1%) and low ID group (0/33; 0%) (p = 0.04). CONCLUSIONS: Although an ID < 1.3 in growth-friendly graduates produces similar outcomes with regard to curve correction and spinal length gain as low and high ID, this study suggests that an ID < 1.3 is associated with an increased revision rate. LEVEL OF EVIDENCE: III.

Prospective Follow-up Report on Anterior Vertebral Body Tethering for Idiopathic Scoliosis: Interim Results from an FDA IDE Study.

BACKGROUND: Anterior vertebral body tethering (aVBT) has emerged as a novel treatment option for patients with idiopathic scoliosis. We present the results from the first U.S. Food and Drug Administration (FDA) Investigational Device Exemption (IDE) study on aVBT. METHODS: In this prospective review of a retrospective data set, eligible patients underwent aVBT at a single center from August 2011 to July 2015. Inclusion criteria included skeletally immature patients with Lenke type-1A or 1B curves between 30° and 65°. Clinical and radiographic parameters were collected, with the latter measured by an independent reviewer. RESULTS: Fifty-seven patients (49 girls and 8 boys), with a mean age (and standard deviation) of 12.4 ± 1.3 years (range, 10.1 to 15.0 years), were enrolled in the study. The patients had a mean of 7.5 ± 0.6 levels tethered, the mean operative time was 223 ± 79 minutes, and the mean estimated blood loss was 106 ± 86 mL. The patients were followed for an average of 55.2 ± 12.5 months and had a mean Risser grade of 4.2 ± 0.9 at the time of the latest follow-up. The main thoracic Cobb angle was a mean of 40.4° ± 6.8° preoperatively and was corrected to 18.7° ± 13.4° at the most recent follow-up. In the sagittal plane, T5-T12 kyphosis measured 15.5° ± 10.0° preoperatively, 17.0° ± 10.1° postoperatively, and 19.6° ± 12.7° at the most recent follow-up. Eighty percent of patients had curves of <30° at the most recent follow-up. The most recent Scoliosis Research Society (SRS) scores averaged 4.5 ± 0.4, and scores on the self-image questionnaire averaged 4.4 ± 0.7. No major neurologic or pulmonary complications occurred. Seven (12.3%) of 57 patients had a revision: 5 were done for overcorrection and 2, for adding-on. CONCLUSIONS: Anterior VBT is a promising technique that has emerged as a treatment option for patients with immature idiopathic scoliosis. We present the results from the first FDA-approved IDE study on aVBT, which formed the basis for the eventual Humanitarian Device Exemption approval. The findings affirm the safety and efficacy of this technique and suggest opportunities for improvement, particularly with respect to reoperation rates. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Early and late hospital readmissions in adolescent idiopathic scoliosis.

STUDY DESIGN: Retrospective review of a prospectively collected multicenter database. OBJECTIVES: To identify risk factors for early and late readmission of surgically treated patients with adolescent idiopathic scoliosis (AIS). Specific risk factors associated with readmission in patients with AIS remain poorly understood. METHODS: Patients with AIS who were operatively treated from 19 centers specializing in the treatment of pediatric spinal deformity were studied. Data from a minimum 2 years of clinical follow-up and any readmission were available for analysis. Characteristics of patients with no readmission, early readmission (< 90 days), and late readmission (> 90 days) were evaluated. Both univariate and multivariate analyses of risk factors for readmission were performed. RESULTS: 2049 patients were included in our cohort, with 1.6% requiring early readmission and 3.3% late readmission. In the multivariate analysis, greater preoperative coronal imbalance was associated with early readmission. Longer operative time was associated with late readmission. Finally, greater preoperative pain (SRS-22 pain scale) was associated with both early and late readmission. GI complications accounted for a higher proportion of early readmissions than previously reported in the literature. CONCLUSIONS: Preoperative counseling of patients with higher levels of pain and coronal imbalance and the implementation of a thorough postoperative bowel regimen may help optimize patient outcomes. LEVEL OF EVIDENCE: 3.

What happens to the unfused upper thoracic curve after posterior spinal fusion for adolescent idiopathic scoliosis?

OBJECTIVE: Spontaneous lumbar curve correction after selective thoracic fusion in surgery for adolescent idiopathic scoliosis (AIS) is well described. However, only a few articles have described the course of the uninstrumented upper thoracic (UT) curve after fusion, and the majority involve a hybrid construct. In this study, the authors sought to determine the outcomes and associated factors of uninstrumented UT curves in patients with AIS. METHODS: The authors retrospectively reviewed a prospectively collected multicenter AIS registry for all consecutive patients with Lenke type 1-4 curves with a 2-year minimum follow-up. UT curves were considered uninstrumented if the upper instrumented vertebra (UIV) did not extend above 1 level from the lower end vertebra of the UT curve. The authors defined progression as > 5°, and divided patients into two cohorts: those with improvement in the UT curve (IMP) and those without improvement in the UT curve (NO IMP). Radiographic, demographic, and Scoliosis Research Society (SRS)-22 survey outcome measures were compared using univariate analysis, and significant factors were compared using a multivariate regression model. RESULTS: The study included 450 patients (370 females and 80 males). The UT curve self-corrected in 86% of patients (n = 385), there was no change in 14% (n = 65), and no patients worsened. Preoperatively, patients were similar with respect to Lenke classification (p = 0.44), age (p = 0.31), sex (p = 0.85), and Risser score (p = 0.14). The UT curves in the IMP group self-corrected from 24.7° ± 6.5° to 12.6° ± 5.9°, whereas in the NO IMP group UT curves remained the same, from 20.3° ± 5.8° to 18.5° ± 5.7°. In a multivariate analysis, preoperative main thoracic (MT) curve size (p = 0.004) and MT curve correction (p = 0.001) remained significant predictors of UT curve improvement. Greater correction of the MT curve and larger initial MT curve size were associated with greater likelihood of UT curve improvement. CONCLUSIONS: Spontaneous UT curve correction occurred in the majority (86%) of unfused UT curves after MT curve correction in Lenke 1-4 curve types. The magnitude of preoperative MT curve size and postoperative MT curve correction were independent predictors of spontaneous UT curve correction.