Larson, A. Noelle

OBJECTIVESurgery for severe congenital defects, such as congenital diaphragmatic hernia, congenital heart defects, and tracheoesophageal disorders, are life-saving treatments for many infants. However, the incidence of scoliosis following thoracoabdominal surgery has been reported to range from 8% to 50%. Little is known about severe scoliosis that occurs after chest wall procedures in infants. The authors sought to determine the prevalence of thoracogenic scoliosis, disease severity, and need for scoliosis surgery in patients who underwent chest wall procedures in early childhood.METHODSA multicenter database of patients with early-onset scoliosis was queried to identify patients with a history of thoracogenic or acquired iatrogenic scoliosis. Patients with significant congenital spine deformities were excluded. Forty-one patients (1.6%) were noted to have thoracogenic scoliosis. Of these patients, 14 patients were observed; 10 received casts and/or braces; and 17 underwent treatment with rib-based distraction rods, Shilla procedures, or spine-based growing rod devices. Radiographs, complications, and patient characteristics were reviewed.RESULTSThe mean age at scoliosis diagnosis for the 41 patients was 6.0 years. The mean time to follow-up was 2.9 years (4.5 years in the 17 surgical patients). The mean preoperative coronal Cobb angle in the surgical group was 65° and improved to 47° postoperatively (p = 0.01). The mean Cobb angle for the nonoperative group was 31° initially and 32° at follow-up (p = 0.44). Among the 17 patients undergoing surgery for scoliosis, there were 13 complications in 7 patients, including a brachial plexus palsy following rib-based distraction rod placement. This resolved with revision of the rib hooks. There were no known complications in the nonoperative cohort.CONCLUSIONSSevere scoliosis can develop after thoracoabdominal surgeries during infancy. Further work is needed to understand the pathogenesis of scoliosis in this population so as to implement measures for prevention and early diagnosis and to guide appropriate treatment.

ABSTRACTDegenerative disk disease of the spine is a major cause of back pain and disability. Optimization of regenerative medical therapies for degenerative disk disease requires a deep mechanistic understanding of the factors controlling the structural integrity of spinal tissues. In this investigation, we sought to identify candidate regulatory genes controlling extracellular matrix synthesis in spinal tissues. To achieve this goal we performed high throughput next generation RNA sequencing on 39 annulus fibrosus and 21 nucleus pulposus human tissue samples. Specimens were collected from patients undergoing surgical discectomy for the treatment of degenerative disk disease. Our studies identified associations between extracellular matrix genes, growth factors, and other important regulatory molecules. The fibrous matrix characteristic of annulus fibrosus was associated with expression of the growth factors platelet derived growth factor beta (PDGFB), vascular endothelial growth factor C (VEGFC), and fibroblast growth factor 9 (FGF9). Additionally we observed high expression of multiple signaling proteins involved in the NOTCH and WNT signaling cascades. Nucleus pulposus extracellular matrix related genes were associated with the expression of numerous diffusible growth factors largely associated with the transforming growth signaling cascade, including transforming factor alpha (TGFA), inhibin alpha (INHA), inhibin beta A (INHBA), bone morphogenetic proteins (BMP2, BMP6), and others. Clinical significance: this investigation provides important data on extracellular matrix gene regulatory networks in disk tissues. This information can be used to optimize pharmacologic, stem cell, and tissue engineering strategies for regeneration of the intervertebral disk and the treatment of back pain. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1356–1369, 2018.

In clinical settings, doctors classify pulmonary disorders into two main categories, obstructive lung disease and restrictive lung disease. The former is characterized by the airway obstruction which is associated with several disorders like chronic bronchitis, asthma, bronchiectasis, and emphysema [1]. The latter is caused by different conditions where one of the triggers is tied to the spine deformity. In general, a pulmonary function test (PFT) [2] is used to evaluate and diagnose lung function, and physicians depend on the test results to identify the disease patterns of the patients (obstructive or restrictive lung disease). In the PFT, some parameters including total lung capacity (TLC), vital capacity (VC), and residual volume (RV) can infer the lung volume and lung capacity. Other parameters, such as forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1), are often employed to assess the pulmonary mechanics. Scoliosis is an abnormal lateral curvature of the spine which involves not only the curvature from side to side but also an axial rotation of the vertebrae. Restrictive lung disease often happens in scoliosis patients, especially with severe spine deformity. Spine deformity if left untreated may lead to progression of the spinal curve, respiratory complications, and the reduction of life expectancy due to the decrease in thoracic volume for lung expansion. However, the relationship between thoracic volume and pulmonary function is not broadly discussed, and anatomic abnormalities in spine deformity (ex: scoliosis, kyphosis, and osteoporosis) can affect thoracic volume. Adequate thoracic volume is needed to promote pulmonary function. Previous literature has shown that the deformity of the thoracic rib cage will have detrimental effects on the respiratory function in adolescent idiopathic scoliosis patients [3–4]. In this paper, we aim to correlate thoracic volume and the parameters in PFTs in adult scoliosis patients 25–35 years after receiving treatments during their adolescence, either with physical bracing or spinal fusion surgery.

Study Design. Biomechanical analysis of 3D correction and bone–screw forces through numerical simulations of scoliosis instrumentation with different pedicle screw patterns. Objective. To analyze the effect of different screw densities and distributions on 3D correction and bone–screw forces in adolescent idiopathic scoliosis (AIS) instrumentation. Summary of Background Data. Instrumentation constructs with various numbers of pedicle screws and patterns have been proposed for thoracic AIS instrumentation. However, systematic biomechanical studies have not yet been completed on the appropriate screw patterns for optimal 3D correction. Methods. Patient-specific biomechanical models of the spine were created for 10 AIS cases (Lenke 1). For each case, surgical instrumentation patterns were computationally simulated using respectively a reference screw pattern (two screws per level fused) and six alternative screw patterns with fewer screws. Simulated surgical maneuvers and model definition were unchanged between simulations except the number and distribution of screws. 3D correction and bone–screw forces were compared. Results. A total of 140 posterior instrumentations were computationally simulated. Mean corrections in the coronal and sagittal planes with alternative screw patterns were within 4° to the reference pattern. Increasing screw density in the apical region from one to two screws per level improved percent apical vertebral rotation (AVR) correction (r = 0.887, P < 0.05). Average bone–screw force associated with the reference screw pattern was 243N ± 54N and those with the alternative screw patterns were 11% to 48% lower. Conclusion. Compared with the reference maximal screw density pattern, alternative screw patterns allowed similar corrections in the coronal and sagittal planes. AVR correction was strongly correlated with screw density in the apical region; AVR correction varied significantly with screw patterns of the same overall screw density when an en bloc vertebral derotation technique was simulated. High screw density tended to overconstrain the instrumented spine and resulted in higher forces at the bone–screw interface. Level of Evidence: N/A

Background: Adjacent segment pathology is a known complication after spinal fusion, but little has been reported on junctional failure. A series of adolescent patients presented with acute distal junctional failure (DJF). We sought to determine any common features of these patients to develop a prevention strategy. Methods: A retrospective review was conducted of pediatric patients who developed DJF after instrumented spinal fusion performed at 2 institutions from 1999 to 2013. Patients with proximal junctional failure or junctional kyphosis without failure were excluded. Results: Fifteen subjects were identified with mean follow-up of 38 months. Distal failure occurred a mean of 60 days after index surgery, with history of minor trauma in 4 patients. Failures included 3-column Chance fracture (11) or instrumentation failure (4). Thirteen patients presented with back pain and/or acute kyphosis, whereas 2 asymptomatic patients presented with healed fractures. Two patients also developed new onset of severe lower extremity neurological deficit after fracture, which improved but never resolved after revision. A total of 13/15 subjects required revision surgery, typically within 1 week. Complications associated with revision surgery were encountered in 8 patients (62%). Major complications that required return to the operating room included 2 deep infections, 2 instrumentation failures, and dense lower extremity paralysis that improved after medial screw revision and decompression. At final follow-up, 10 patients are asymptomatic, 2 have persistent neurological deficit, 2 have chronic pain, and 1 has altered gait with gait aid requirement. Conclusions: This study analyzes a heterogenous cohort of spinal fusion patients who developed DJF from 3-column Chance fracture or instrumentation failure. Revision surgery is typically required, but has a high complication rate and can result in severe neurological deficit, highlighting the morbidity of this complication. It is unclear whether level of the lowest instrumented vertebra contributes to DJF. Increased awareness of junctional failure in children may prompt additional studies to further characterize risk factors and preventative strategies. Level of Evidence: Level IV—study-type case series.

Background: In pediatric patients, pedicle screws are malpositioned 5% to 15% of the time. Complications associated with malpositioned screws are infrequently reported in the literature. We present a series of adolescent idiopathic scoliosis (AIS) patients who presented in a delayed manner with positional headache and chronic dural leak adjacent to the pedicle screw tract. Methods: Scoliosis databases at 2 centers were reviewed, and cases of delayed positional headaches following posterior spinal fusion for AIS were identified. Demographic and clinical data were collected. Results: Of 322 patients, 4 patients presented with positional headaches at a mean of 12.8 weeks following posterior spinal fusion surgery for AIS, with an interval time to diagnosis of 5 months. Computed tomographic myelogram demonstrated severe pedicle screw malposition in 1 patient, and minimal malposition in 3 patients (<2 mm violation). The patients had delayed presentation with positional headaches secondary to dural leak. All patients successfully underwent revision surgery with repair of the dural leak. At the time of latest follow-up, all patients are asymptomatic. Conclusions: Pedicle screw malposition can result in dural leaks. Patients may present in a delayed manner with positional headaches and an acquired Chiari malformation. Clinical suspicion should prompt imaging of the brain or cervical spine followed by computed tomographic myelogram to determine site of leak. This is a rare complication from pedicle screw malposition. Levels of Evidence: Level IV—case series.

Background: The purpose of this study was to determine the frequency with which postoperative radiographs resulted in a change in management following closed reduction and percutaneous pinning of displaced pediatric supracondylar humerus fractures. We hypothesize that only the initial postoperative radiograph will lead to changes in management of operative supracondylar humerus fractures. Methods: A retrospective review was performed at 2 level I pediatric trauma centers. Inclusion criteria were patients below 18 years of age who sustained supracondylar humerus fractures (Gartland type II, III, IV) who were operatively treated from 2008 to 2013 with adequate radiographic follow-up. Patients with flexion type, intra-articular, transphyseal, and open fractures were excluded from the study. Routine radiographs were taken at initial follow-up (1 wk postoperatively) and at pin removal (3 to 4 wk postoperatively). Results: The final analysis included 572 patients. Initial postoperative radiographs changed treatment in 9 patients (1.6%), including revision surgeries, 2 pin adjustments, and 2 early pin removals. At the time of pin removal, 20 (3.5%) patients required further immobilization. There were no changes to the initial plan for continued nonoperative treatment at final follow-up (6 to 8 wk postoperatively). Conclusions: In this large retrospective series of patients treated with closed reduction and percutaneous pinning of displaced supracondylar humerus fractures, radiographs at 3 weeks do not reveal a need to return to the operating room or other significant pathology. These findings suggest that radiographs should be obtained within 7 to 10 days postoperatively for type III fractures and may only need to be repeated if the clinical situation warrants it, such as severe fracture pattern, persistent pain, or clinical deformity. Level of Evidence: Level IV—case series.

Background: Surgical indications for Scheuermann kyphosis are variable. We sought to evaluate the characteristics of patients undergoing operative versus nonoperative treatment of Scheuermann kyphosis to better understand current practices and the factors which contribute to the decision for surgical management. Methods: Multicenter prospective cohort study. We evaluated consecutive patients presenting with Scheuermann kyphosis. Patients underwent either surgical or nonoperative management according to surgeon and patient discretion. Preoperative patient-reported outcome measures (Scoliosis Research Society and Spinal Appearance Questionnaire scores), demographics, and radiographic characteristics were assessed. Results: Overall, 150 patients with Scheuermann kyphosis were enrolled, with 77 choosing nonoperative treatment and 73 treated operatively. Compared with the nonoperative cohort, patients treated operatively were older (16.3±2.0 vs. 15.1±2.2, P=0.0004), and had higher body mass index (26.3±7.2 vs. 22.7±6.5, P=0.003), had greater T2-T12 kyphosis (71±14 degrees vs. 61±12 degrees, P<0.001), increased pelvic incidence (46 vs. 41 degrees, P=0.03) and pelvic tilt (10 vs. 3 degrees, P=0.03). There was no detected difference in maximal sagittal Cobb angle in the operative versus nonoperative patients (73±11 vs. 70±12 degrees, P=0.11). Functionally, the operative patients had worse Scoliosis Research Society pain scores (3.7±0.9 vs. 4.1±0.7, P=0.0027) and appearance scores (2.9±0.7 vs. 3.4±0.8, P <0.0001). Conclusions: Patients undergoing surgical management of Scheuermann disease were more likely to have large body mass index and worse pain scores. Other factors beyond radiographic measurement likely contribute to the decision for surgical management of Scheuermann kyphosis. Level of Evidence: Level II.