Musculoskeletal phenotypes in 3q29 deletion syndrome.

3q29 deletion syndrome (3q29del) is a rare genomic disorder caused by a 1.6 Mb deletion (hg19, chr3:195725000-197350000). 3q29del is associated with neurodevelopmental and psychiatric phenotypes, including an astonishing >40-fold increased risk for schizophrenia, but medical phenotypes are less well-described. We used the online 3q29 registry of 206 individuals (3q29deletion.org) to recruit 57 individuals with 3q29del (56.14% male) and requested information about musculoskeletal phenotypes with a custom questionnaire. 85.96% of participants with 3q29del reported at least one musculoskeletal phenotype. Congenital anomalies were most common (70.18%), with pes planus (40.35%), pectus excavatum (22.81%), and pectus carinatum (5.26%) significantly elevated relative to the pediatric general population. 49.12% of participants reported fatigue after 30 min or less of activity. Bone fractures (8.77%) were significantly elevated relative to the pediatric general population. Participants commonly report receiving medical care for musculoskeletal complaints (71.93%), indicating that these phenotypes impact quality of life for individuals with 3q29del. This is the most comprehensive description of musculoskeletal phenotypes in 3q29del to date, suggests ideas for clinical evaluation, and expands our understanding of the phenotypic spectrum of this syndrome.

Musculoskeletal phenotypes in 3q29 deletion syndrome.

3q29 deletion syndrome (3q29del) is a rare genomic disorder caused by a 1.6 Mb deletion (hg19, chr3:195725000â€"197350000). 3q29del is associated with neurodevelopmental and psychiatric phenotypes, including an astonishing >40-fold increased risk for schizophrenia, but medical phenotypes are less well-described. We used the online 3q29 registry ( 3q29deletion.org ) to recruit 57 individuals with 3q29del (56.14% male) and requested information about musculoskeletal phenotypes with a custom questionnaire. 85.96% of participants with 3q29del reported at least one musculoskeletal phenotype. Congenital anomalies were most common (70.18%), with pes planus (40.35%), pectus excavatum (22.81%), and pectus carinatum (5.26%) significantly elevated relative to the pediatric general population. 49.12% of participants reported fatigue after 30 minutes or less of activity. Bone fractures (8.77%) were significantly elevated relative to the pediatric general population, suggesting 3q29del impacts bone strength. Participants commonly report receiving medical care for musculoskeletal complaints (71.93%), indicating that these phenotypes impact quality of life for individuals with 3q29del. This is the most comprehensive description of musculoskeletal phenotypes in 3q29del to date, suggests ideas for clinical evaluation, and expands our understanding of the phenotypic spectrum of this syndrome.

Primary Aneurysmal Bone Cyst of the Spine in Children: Updated Outcomes of a Modern Surgical Technique.

OBJECTIVE: Aneurysmal bone cysts (ABC) are benign but locally aggressive lesions. Treating children with spinal ABC poses risks due to the proximity of the lesion to the spinal cord and the need to preserve spinal stability after surgery. This study reports the updated outcomes of a uniform aggressive initial surgical technique for the treatment of spinal ABC in children. METHODS: Twenty-nine cases of spinal ABC were collected from a tertiary pediatric tumor center over a 24-year period (January 1990-September 2014). The study patients were divided into 2 groups based on the performed procedure: a traditional approach consisting of curettage and bone grafting (group 1) and a 4-step approach consisting of intralesional curettage, high-speed bur, electrocautery, and bone grafting (group 2). RESULTS: The study population was composed of 12 males and 17 females with a mean age of 12.2 years at the time of diagnosis and a mean postoperative follow-up of 4.03 years. Twenty-one patients underwent the 4-step approach, while 8 patients were treated with the traditional technique. The recurrence rate was 50% (4/8 patients) with the traditional technique (group 1) and 19% (4/21) in the 4-step technique (group 2) (P = .164). Regardless of the technique used, the presence of sensory symptoms at the time of presentation was a statistically significant factor for recurrence (P = .016). CONCLUSIONS: We suggest that addressing spinal ABC in pediatric patients with a 4-step approach is a safe technique that may decrease long-term recurrence and reoperation rates compared to the traditional technique of intralesional curettage and bone grafting. LEVEL OF EVIDENCE: 4.

Correction to: Is the new ASNM intraoperative neuromonitoring supervision "guideline" a trustworthy guideline? A commentary.

The article Is the new ASNM intraoperative neuromonitoring supervision "guideline" a trustworthy guideline? A commentary, written by Stanley A. Skinner, Elif Ilgaz Aydinlar, Lawrence F. Borges, Bob S. Carter, Bradford L. Currier, Vedran Deletis, Charles Dong, John Paul Dormans, Gea Drost, Isabel Fernandez­Conejero, E. Matthew Hoffman, Robert N. Holdefer, Paulo Andre Teixeira Kimaid, Antoun Koht, Karl F. Kothbauer, David B. MacDonald, John J. McAuliffe III, David E. Morledge, Susan H. Morris, Jonathan Norton, Klaus Novak, Kyung Seok Park, Joseph H. Perra, Julian Prell, David M. Rippe, Francesco Sala, Daniel M. Schwartz, Martín J. Segura, Kathleen Seidel, Christoph Seubert, Mirela V. Simon, Francisco Soto, Jeffrey A. Strommen, Andrea Szelenyi, Armando Tello, Sedat Ulkatan, Javier Urriza and Marshall Wilkinson, was originally published electronically on the publisher's internet portal (currently SpringerLink) on 05 January 2019 without open access. With the author(s)' decision to opt for Open Choice the copyright of the article changed on 30 January 2019 to © The Author(s) 2019 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made. The original article has been corrected.

Cost Analysis of Magnet-driven Growing Rods for Early-onset Scoliosis at 5 Years.

STUDY DESIGN: Prospective case series of nine children with early-onset scoliosis (EOS) treated by a single surgeon with a novel implant, the magnet-driven growing rod (MdGR) in a publicly funded health care service accounting for "payer costs" (PC) incurred. OBJECTIVE: The aim of this study was to compare the cost-effectiveness of MdGR versus conventional growing rods (CGRs) with respect to the PC incurred for treating EOS at 5 years. SUMMARY OF BACKGROUND DATA: Cost estimate and mathematical modeling study projections of MdGR have shown despite high insertional costs, it breaks even with CGR by 3 to 4 years. However, no clinical study to date exists either supporting or refuting this hypothesis. METHODS: Nine patients with EOS secondary to idiopathic (two), congenital (one), syndromic (three), and neuromuscular (three) etiologies treated by submuscular insertion of MdGR against stringent inclusion criteria formed the study cohort. We collected costs incurred with all aspects of care over the lifetime of device (or at least 5 years) from payers' perspective to compute and report average PC incurred per patient. We performed this cost analysis by comparing the MdGR PC against literature reported PC for CGR at 5 years. RESULTS: There were five single rod (SR) and two dual rod (DR) de novo MdGR insertions, while two patients had conversion of CGR to MdGR. MdGR alone accounted for at least 50% of overall budget. The MdGR was at least 40% more cost-effective in comparison to the CGR (£34,741 vs. £52,293) and there were seven MdGR graduates. CONCLUSION: The first study reporting direct PC incurred in EOS treated by MdGR that is devoid of any mathematical modeling and deterministic sensitivity analysis is presented. The true societal/human cost savings taking into consideration indirect costs are likely to be significantly higher. MdGR is a promising novel implant that may eventually become the "standard of care" for certain EOS etiologies. LEVEL OF EVIDENCE: 4.

Clinical and radiographic presentation of pelvic sarcoma in children.

INTRODUCTION: Pelvic sarcomas may present with vague symptoms. The aim of this study was to examine the characteristics and clinical presentations of different types of pelvic sarcoma in children. METHODS: This is a retrospective cohort study of patients up to 21 years of age with the diagnosis of pelvic sarcoma between January 2000 and June 2013. Data on demographics, tumor type and location, and clinical presentation were collected from the medical records. RESULTS: A total of 59 patients [37 males (62.7%) and 22 females (37.3%)] were examined in this study. Mean age at presentation was 11.3 ± 5 years (range 0.8-21 years). Thirty-six patients had Ewing sarcoma (61%), 9 osteosarcoma (6.8%), 4 undifferentiated sarcoma (6.8%), 2 (3.4%) rhabdomyosarcoma, 2 synovial cell sarcoma, and one (1.7%) of each fibrosarcoma, dermatofibrosarcoma, fibromyxoid sarcoma, chondrosarcoma, chordoma, and epithelioid sarcoma. Pain at presentation was reported in 41 patients, 13 mass, 8 limping, and 5 neurologic symptoms. Most of the bony tumors were painful (77%), while most of the soft tissue tumors were painless (70%). Nine patients presented with constitutional symptoms. Most patients presented within 4-12 months from symptoms beginning. Twenty-one patients (35.6%) presented with metastases (14 Ewing sarcoma, 6 osteosarcoma, and 1 synovial cell sarcoma). Pelvic radiographs showed lytic lesion in 11 patients, 4 sclerotic lesions, 6 mixed lesion, 6 had only soft tissue mass, 1 radiograph showed osteopenia, and 2 radiographs were reported normal. CONCLUSION: Ewing sarcoma was the most common pelvic sarcoma tumor in children. In most cases, pelvic sarcoma in children presented with pain mimicking other benign conditions. Some patients presented with metastatic disease with no prognostic clinical or radiographical signs or symptoms. Pelvic sarcoma should be considered a differential diagnosis as part of children work up.

Single stage en bloc resection of a recurrent metastatic osteosarcoma of the pediatric lumbar spine through multiple exposures - a novel approach.

To obtain a wide resection and safe margins in recurrent spine osteosarcoma, the surgical approach can include - posterior only, combined posterior and anterior, and combined posterior and anterior with a return to posterior in multiple stages. In our case, we used a novel approach of multiple extensile exposures circumferentially in a single stage with a single surgical prep. We present the case of a 9-year-old female with a history of metastatic osteosarcoma, who previously underwent an attempted en bloc resection with an L3 corpectomy and left below knee amputation. At 1 year follow-up, she developed a recurrent solitary spine lesion at the previous surgical resection site. An additional attempt at complete surgical resection was performed with a complex en bloc L2, L3, L4 corpectomy with removal of deep spinal implants and anterior and posterior spinal fusion with instrumentation and revision decompressive laminectomy. The patient had a good functional outcome without neurological deficits, except those resulting from resection of involved lumbar nerve roots. At last follow-up of 5 months, there was no local recurrence or distant metastasis. This approach for revision resection of recurrent spinal osteosarcoma can be performed successfully with clean margins in a safe manner.

Atlantoaxial rotatory displacement in children.

AIM: To correlate the Pang and Lee class with the clinical course in a consecutive series of patients presenting with painful torticollis. METHODS: Forty-seven dynamic rotational computed tomography (CT) scans in 35 patients were classified into one of the five types defined by Pang and Li, including types I (atlantoaxial rotatopry fixation), II ("pathologic stickiness" without crossover of C1 on C2), III ("pathologic stickiness" with crossover of C1 on C2), IV (normal or muscular torticollis), and V (diagnostic grey zone). The Pang and Li class was then compared with the radiologist's report, which was graded abnormal, diagnosis of rotatory subluxation or fixation, or non-diagnostic. Medical records were reviewed and the clinical course was compared among the five sub-types. RESULTS: We reviewed 47 CT scans in 35 patients, and the majority were performed without sedation. The average age was 7.7 years (4-14 years old) and associated conditions included minor trauma (20%), surgical procedures around the head and neck (29%), and Grisels syndrome (20%). Twenty-six percent of our studies fell within the pathologic spectrum (5% type 1 or rotatory fixation, 21% types 2 and 3 or rotatory subluxation), while 45% were classified as muscular torticollis (45%) and 28% fell within the diagnostic grey zone. Seven radiologists interpreted these studies, and their interpretation was discordant in 45% of cases. Clinical resolution occurred in 27 of 29 cases for which follow-up was available. One of two patients with fixed rotatory subluxation required a C1-C2 arthrodesis. CONCLUSION: The Pang and Li classification characterizes a spectrum of abnormalities in rotation to facilitate communication, although the indications for dynamic CT scan should be further defined.

Surgical treatment of pelvic sarcoma in children: outcomes for twenty six patients.

PURPOSE: Pelvic sarcoma is uncommon in children and challenging to treat. This study examined different surgical approaches to treat pelvic sarcoma with the aim of assessing the oncologic, and functional outcomes. METHODS: We retrospectively examined the medical records of patients younger than 21 years of age who underwent surgery for pelvic sarcoma at our institution from 1992 to 2010. The functional status of the patients was examined after a minimum follow-up of two years. RESULTS: Twenty-six patients were included in the analysis. Nineteen (73%) patients were male and seven (27%) were female. Mean age at presentation was 12.0 ± 3.9 years. Nineteen patients had Ewing sarcoma (73%), five had osteosarcoma (19%), one had chondrosarcoma (4%) and one had rhabdomyosarcoma (4%). Iliac wing resection with no reconstruction was done in three patients. Reconstruction with free fibular graft A-frame was performed in four patients, saddle endoproshtesis in five patients, iliac autoclave in one patient, and internal hemipelvectomy in nine patients. Hindquarter amputation was performed in five patients. Median follow-up was 4.6 years (range, 2.6-16 years). Nineteen patients were alive (73%); of those, 13 were known to be without disease, three were with disease and three did not have known tumor status. Six patients were reported deceased, three had osteosarcoma and three had Ewing sarcoma. Function was assessed in 17 patients; 64% were asymptomatic and ambulatory and 36% were symptomatic and ambulatory. CONCLUSIONS: Salvage reconstruction for pelvic sarcoma can be performed through various procedures on the extent of necessary bony resection. Survival rate and functional outcomes were promising in the performed study.

Hematogenous Osteomyelitis in Infants and Children: Imaging of a Changing Disease.

In children, hematogenous osteomyelitis is an infection that primarily affects the most vascularized regions of the growing skeleton. The disease has increased in frequency, virulence, and degree of soft-tissue involvement. The change in clinical manifestations and management over the past 2 decades should be reflected in the current imaging approach to the disease. Imaging of infection must depict the location of a single focus or of multiple foci of involvement and the presence of drainable collections. This review provides an overview of the imaging implications directed by the changing epidemiology, the newer insights of anatomy and pathophysiology, the imaging characteristics with emphasis on specific locations and disease complications, and the differential diagnosis considerations. In addition, basic imaging guidelines for appropriate extent of area to image based on patient age are provided. © RSNA, 2017.

Optimal Diagnostic Yield Achieved With On-site Pathology Evaluation of Fine-Needle Aspiration-Assisted Core Biopsies for Pediatric Osseous Lesions: A Single-Center Experience.

CONTEXT: - Image-guided, fine-needle aspiration-assisted core needle biopsy with an on-site evaluation by a pathologist (FNACBP) of osseous lesions is not a common practice in pediatric institutions. OBJECTIVES: - To evaluate the diagnostic adequacy and accuracy of FNACBP for pediatric osseous lesions and to compare the adequacy with procedures that do not use fine-needle aspiration. DESIGN: - Six-year, retrospective review of 144 consecutive children biopsied for osseous lesions with and without fine-needle aspiration assistance. RESULTS: - Pathologic diagnosis was achieved in 79% (57 of 72) of the core biopsies without an on-site evaluation, 78% (32 of 41) of the open biopsies (9 with intraoperative consultation), and 97% (30 of 31) of the FNACBPs as the initial diagnostic procedure. Three FNACBP cases were preceded by nondiagnostic open biopsies. Among 34 lesions sampled by FNACBP, 33 (97%) succeeded with diagnostic tissue, with most (30 of 33; 91%) being neoplasms, including 16 malignant (48%), 13 benign (39%), and 1 indeterminate (3%) lesions. The most-common diagnoses were osteosarcoma (9 of 33; 27%) and Langerhans cell histiocytosis (7 of 33; 21%). In cases with follow-up information available, 93% (28 of 30) of the FNACBP-rendered diagnoses were clinically useful, allowing initiation of appropriate therapy. The FNACBP procedure had 100% specificity, sensitivity, and positive predictive value for all 14 malignant lesions, with the sensitivity being 88% in benign lesions. Most FNACBP procedures (32 of 34; 94%) yielded adequate material for ancillary testing. A gradual upward trend was observed for the choice of FNACBP as an initial diagnostic procedure for osseous lesions. CONCLUSIONS: - The FNACBP procedure yields sufficient material for diagnosis and ancillary studies in pediatric, osseous lesions and may be considered an initial-diagnostic procedure of choice.

Surgical resection of osteoid osteoma and osteoblastoma of the spine.

Intraoperative radiographic guidance has traditionally been utilized in orthopedic surgery through 2-D navigation with the C-arm and recently with 3-D navigation with the O-arm. The aim of this study was to describe the outcome of surgical treatment of spinal osteoblastoma and osteoid osteoma with the utilization of the O-arm and conventional C-arm guidance. This is a retrospective cohort study of patients with spinal osteoid osteoma and or osteoblastoma who were treated at our institution between 2002 and 2011. Seventeen patients were examined in this study including seven with spinal osteoblastoma and 10 with spinal osteoid osteoma. The mean age of the patients at surgery was 11.5±3.9 years. The O-arm was used in seven patients and the C-arm in 10 patients. The C-arm failed to identify the tumor in one case and needed transport to perform a computed tomographic-scan. The length of surgery was shorter when the O-arm was used, especially in the osteoblastoma group. Thirteen patients were pain free at the last follow-up visit and two patients developed recurrence. Radiographs at the last follow-up did not show signs of vertebral instability following tumor resection. Safe and effective localization of spine tumors and confirmation of tumor removal during surgery was achieved by intraoperative radiographic guidance specifically with the O-arm 3-D navigation system. LEVEL OF EVIDENCE: III.

Rod fracture and lengthening intervals in traditional growing rods: is there a relationship?

PURPOSE: Is there any relationship between lengthening intervals and rod fracture in traditional growing rod (TGR) surgery? METHODS: A multicenter EOS database was queried for patients who had: (1) dual growing rods for EOS; (2) minimum 2-year follow-up; (3) a minimum of 2 lengthenings; and (4) revision surgery due to rod fracture. Of 138 patients who met the criteria: 56 patients experienced at least one-rod fracture (RF group) and 82 patients had no rod fractures (NRF group). In addition to each patient's lengthening intervals, demographics, construct details, and radiographic parameters were compared. RESULTS: RF and NRF patients had a mean pre-op age of 5.7 years (range 1.3-10.7) and 7.3 years (range 1.6-12.8), respectively (p < 0.001). There was no significant association between etiologies and rod fracture or between BMI and rod fracture (p = 0.979). There was no significant difference between lengthening intervals between the RF and NRF groups (p > 0.05). RF and NRF patients had statistically similar mean pre-op major curve size and max kyphosis (p = 0.279; p = 0.619, respectively). Stainless steel rods fractured more frequently compared with Titanium rods (SS 49.2 % vs. Ti 38 %; p = 0.004). Rod fracture occurred more in rods smaller than 4 mm (p = 0.011). CONCLUSIONS: Lengthening intervals were not statistically different in RF and NRF groups and there was no association between lengthening interval and rod fracture in TGR cases. It was shown that patients who had rod fracture were younger and were more likely to have SS rods with smaller than 4 mm diameter.

Observational Analysis of Changing Trends in Level of Evidence of Scoliosis Research Society Annual Meeting Podium Presentations in the New Millennium (2001-2013).

STUDY DESIGN: Observational quantitative evaluation of all Scoliosis Research Society annual meeting (SRS-AM) podium presentations over a 6-year period in the new millennium for changing trends in Level of Evidence (LoE). OBJECTIVES: To report the LoE of SRS-AM podium presentations over a 13-year period in the new millennium and to compare the trends in LoE over a 3-year period between the two decades, that is, 2001-2003 versus 2011-2013. SUMMARY OF BACKGROUND DATA: LoE is a rating system introduced by the American Academy of Orthopaedic Surgeons (AAOS) in 2003 to reflect the quality of clinical studies. No study has looked into any of AAOS-affiliated spinal specialist societies' LoE, hence this study. METHODS: The SRS-AM proceedings books from two 3-year periods, 2001-2003 and 2011-2013, were retrieved. Two orthopedic surgeons independently graded each abstract on two occasions, 1 month apart, assigning them LoE from I to V, in accordance with the stringent guidelines published by AAOS. They also categorized all studies into types (ie, therapeutic, prognostic, diagnostic, economic or decision-modeling analysis, or LoE not applicable). Any disagreement between the two assessors over the LoE or the nature of study was discussed, and agreed upon by consensus. Thus, analyzed abstracts of the two groups were subsequently compared and subjected to statistical tests to determine significance. RESULTS: 637 free-papers from six annual meeting proceedings (264 in Group I and 373 in Group II) were analyzed in total. LoE I and II studies have more than doubled (p<.0001), and LoE IV studies have fallen by half in 2011-2013 as compared to 2001-2003. CONCLUSION: The SRS-AM podium presentation has shown an increase in LoE I and II studies in the new millennium. SRS is the first AAOS-affiliated subspecialty society to have undertaken an in-depth analysis of its AM podium presentations, setting a standard for other societies to emulate. LEVEL OF EVIDENCE: Not applicable.

Outcomes of Spinal Fusion for Cervical Kyphosis in Children with Neurofibromatosis.

BACKGROUND: Cervical kyphosis may occur with neurofibromatosis type I (NF1) and is often associated with vertebral dysplasia. Outcomes of cervical spinal fusion in patients with NF1 are not well described because of the rarity of the condition. We aimed to (1) characterize the clinical presentation of cervical kyphosis and (2) report the outcomes of posterior and anteroposterior cervical fusion for the condition in these children. METHODS: The medical records and imaging studies of 22 children with NF1 who had undergone spinal fusion for cervical kyphosis (mean, 67°) at a mean age of 11 years and who had been followed for a minimum of 2 years were reviewed. RESULTS: Thirteen children presented with neck pain; 10, with head tilt; 9, with a previous cervical laminectomy or fusion; and 5, with a neurologic deficit. Two patients had spontaneous dislocation of the mid-cervical spine without a neurologic deficit. Eleven had scoliosis, with the major curve measuring a mean of 61°. Nine patients underwent posterior and 13 underwent anteroposterior surgery. Twenty-one received spinal instrumentation, and 1 was not treated with instrumentation. Preoperative halo traction was used for 9 patients, and it reduced the mean preoperative kyphosis by 34% (p = 0.0059). At the time of final follow-up, all spinal fusion sites had healed and the cervical kyphosis averaged 21° (mean correction, 69%; p < 0.001). The cervical kyphosis correction was significantly better after the anteroposterior procedures (83%) than after the posterior-only procedures (58%) (p = 0.031). Vertebral dysplasia and erosion continued in all 17 patients who had presented with dysplasia preoperatively. Thirteen patients had complications, including 5 new neurologic deficits and 8 cases of junctional kyphosis. Nine patients required revision surgery. Junctional kyphosis was more common in children in whom ≤5 levels had been fused (p = 0.054). CONCLUSIONS: Anteroposterior surgery provided better correction of cervical kyphosis than posterior spinal fusion in children with NF1. Erosion of vertebral bodies continued during the postoperative follow-up period in all patients who had presented with dysplastic changes preoperatively. The cervical spine should be screened in all children with NF1. Fusion should include at least 6 levels to prevent junctional kyphosis. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Bi-planar spinal stereoradiography of adolescent idiopathic scoliosis: considerations in 3D alignment and functional balance.

PURPOSE: A prospective, cross-sectional study to determine the impact of arm position on the 3D spine and pelvic parameters and postural balance in adolescent idiopathic scoliosis. METHODS: A total number of 37 adolescent idiopathic scoliosis patients were enrolled prospectively. Three arm positions, (1) 45° shoulder flexion with knuckles on clavicles, (2) 90° shoulder and elbow flexion with forearms and palms on the front wall, and (3) arms hanging on either side, were instructed to the cohort. Bi-planar low dose X-ray images of the spine and pelvis were registered in a stereoradiography system in the first and second arm positions. A pressure mat recorded the position of the center of pressure in each arm position. Spinal and pelvic parameters were measured for the cohort. Statistical analysis was performed to determine the agreement between the spinal and pelvic parameters and standing balance in different arm positions. RESULTS: Thoracic kyphosis, sacral slope, sagittal vertical axis, T1 tilt, and spinal height were significantly different between the knuckles on clavicle and forearms on the wall positions p < 0.05. Significant differences were observed in the pressure distribution under the feet between the wall and freestanding positions. Bland-Altman plots determined disagreements between the first and second arm positions in clinical measurements and postural assessment of adolescent idiopathic scoliosis. CONCLUSION: The knuckles on clavicles position replicates the functional standing balance in AIS. Significant differences between the spinal and pelvic parameters suggest that the wall and clavicle arm positions should not be used interchangeably in AIS postural assessment. LEVEL OF EVIDENCE: Diagnostic level II.

Characterizing the differences between the 2D and 3D measurements of spine in adolescent idiopathic scoliosis.

PURPOSE: Although adolescent idiopathic scoliosis (AIS) is known to impact the 3D orientation of the spine and pelvis, the impact of the vertebral position relative to the X-ray scanner on the agreement between 2D and 3D measurements of a curve has not been evaluated. The purpose of this study was to investigate the agreement between 2D and 3D measurements of the scoliotic curve as a function of the 3D spinal parameters in AIS. METHODS: Three independent observers measured the thoracic and lumbar Cobb angles, Kyphosis, and lordosis on the posterior-anterior and lateral X-rays of AIS patients. The 3D reconstructions were created from bi-planar X-rays and the 3D spinal parameters were calculated in both radio and patient planes using SterEOS software. The degree of agreement between the 2D and 3D measurements was tested and its relationship with the curve axial rotation was determined. RESULTS: 2D and 3D measurements of the sagittal plane spinal parameters were significantly different (p < 0.05). The differences between the 2D and 3D measurements were related to the apical vertebrae rotation, the orientation of the plane of maximum curvature, pelvic axial rotation, and the curve magnitude. Differences between the radio plane and patient plane measurements were related to the pelvic axial rotation, Cobb angles, and apical vertebrae rotation, p < 0.05. CONCLUSION: Clinically and statistically significant differences were observed between the 2D and 3D measurements of the scoliotic spine. The differences between the 2D and 3D techniques were significant in sagittal plane and were related to the spinal curve and pelvic rotation in transverse plane.