Image-based discrimination of the early stages of mesenchymal stem cell differentiation.

Mesenchymal stem cells (MSCs) are self-renewing, multipotent cells, which can be used in cellular and tissue therapeutics. MSCs cell number can be expanded in vitro, but premature differentiation results in reduced cell number and compromised therapeutic efficacies. Current techniques fail to discriminate the "stem-like" population from early stages (12 h) of differentiated MSC population. Here, we imaged nuclear structure and actin architecture using immunofluorescence and used deep learning-based computer vision technology to discriminate the early stages (6-12 h) of MSC differentiation. Convolutional neural network models trained by nucleus and actin images have high accuracy in reporting MSC differentiation; nuclear images alone can identify early stages of differentiation. Concurrently, we show that chromatin fluidity and heterochromatin levels or localization change during early MSC differentiation. This study quantifies changes in cell architecture during early MSC differentiation and describes a novel image-based diagnostic tool that could be widely used in MSC culture, expansion and utilization.

The Prevalence of Hip Dysplasia on Radiographs for Adolescent Idiopathic Scoliosis.

BACKGROUND: During radiographic assessment of adolescent idiopathic scoliosis (AIS), upright images frequently capture the hip. The purpose of this study was to assess the prevalence of radiographic hip dysplasia on postero-anterior (PA) scoliosis radiographs, as defined as a lateral center edge angle (LCEA) ≤25 degrees. METHODS: All patients with upright PA scoliosis radiographs over a one-year study period at a single tertiary academic medical center (2020 to 2021) were included in the study. Radiographs containing the hip joints were annotated by 3 reviewers for left and right LCEA, and triradiate cartilage (TRC) status. Inter-rater reliability was determined among the 3 reviewers. RESULTS: Two hundred fifty patients {500 hips, 75.6% female, median age 14 [interquartile range (IQR)=3]} had PA scoliosis radiographs that captured the hip, which qualified for analysis. Seventy-four hips (14.8%) demonstrated evidence of dysplasia (LCEA ≤25 deg) in 55/250 patients (22%). The median LCEA was significantly lower in the dysplastic hip cohort (23.9 deg, IQR=4.8 deg), compared with those without dysplasia (33 deg IQR=7.3 deg; P =0.001). A higher percentage of dysplastic hip patients were female than male (72.7% vs. 27.3%). Patients with bilateral dysplasia had a similar LCEA ( 22.9 deg) [to those with unilateral dysplasia (22.9 deg left, 23.9 deg right, P =0.689)]. CONCLUSIONS: In a cohort of 250 AIS patients, 22% demonstrated evidence of hip dysplasia, as defined as an LCEA ≤2 degrees. The dysplastic patients were more likely to be female. Screening for hip symptomatology in AIS patients may be of benefit, considering the frequency of radiographic hip dysplasia in this population. LEVEL OF EVIDENCE: III. Type of Evidence: diagnostic.

Development of Consensus-Based Best Practice Guidelines for the Peri- and Post-operative Care of Pediatric Patients with Spinal Deformity and Programmable Implanted Devices.

STUDY DESIGN: Modified Delphi consensus study. OBJECTIVE: To develop consensus-based best practices for the care of pediatric patients who have implanted programmable devices (IPDs) and require spinal deformity surgery. SUMMARY OF BACKGROUND DATA: Implanted programmable devices (IPDs) are often present in patients with neuromuscular or syndromic scoliosis who require spine surgery. Guidelines for monitoring and interrogating these devices during the peri-operative period are not available. METHODS: A panel was assembled consisting of 25 experts (i.e., spinal deformity surgeons, neurosurgeons, neuro-electrophysiologists, cardiologists, and otolaryngologists). Initial postulates were based on literature review and results from a prior survey. Postulates addressed the following IPDs: vagal nerve stimulators (VNS), programmable ventriculo-peritoneal shunts (VPS), intrathecal baclofen pumps (ITBP), cardiac pacemakers and implantable cardioverter-defibrillators (ICD), deep brain stimulators (DBS), and cochlear implants. Cardiologist and otolaryngologists participants responded only to postulates on cardiac pacemakers or cochlear implants, respectively. Consensus was defined as ≥80% agreement, items that did not reach consensus were revised and included in subsequent rounds. A total of three survey rounds and one virtual meeting were conducted. RESULTS: Consensus was reached on 39 total postulates across six IPD types. Postulates addressed general spine surgery considerations, use of intraoperative monitoring and cautery, use of magnetically-controlled growing rods (MCGRs), and use of an external remote controller to lengthen MCGRs. Across IPD types, consensus for the final postulates ranged from 94.4-100%. Overall, experts agreed that MCGRs can be surgically inserted and lengthened in patients with a variety of IPDs and provided guidance for the use of intraoperative monitoring and cautery, which varied between IPD types. CONCLUSION: Spinal deformity correction surgery often benefits from the use of intraoperative monitoring, monopolar and bipolar cautery, and MCGRs. Final postulates from this study can inform the peri- and post-operative practices of spinal deformity surgeons who treat patients with both scoliosis and IPDs. LEVEL OF EVIDENCE: V- Expert opinion.

Intraoperative Radiation Exposure in Adolescent Idiopathic and Neuromuscular Scoliosis.

BACKGROUND: Intraoperative imaging is often used to aid pedicle screw placement during scoliosis operations. Higher rates of cancer and death have been observed in orthopaedic surgeons and radiation technologists, including a fourfold higher rate of breast cancer in female orthopaedic surgeons. The purpose of this study was to evaluate variability in intraoperative radiation during spinal fusions for both adolescent idiopathic scoliosis (AIS) and neuromuscular scoliosis (NMS). METHODS: A retrospective review of posterior spinal fusion and segmental spinal instrumentation for scoliosis performed by pediatric orthopaedic surgeons from 2017 to 2019 at a single institution was performed. Inclusion criteria included: a diagnosis of AIS or NMS and patients between 8 and 18 years of age. Exclusion criteria included: revision surgery, use of intraoperative navigation, and patients younger than 10 at the time of scoliosis onset within the AIS cohort. Data collected included: preoperative curve, body mass index (BMI), number of levels fused, number of Ponte osteotomies, and fluoroscopy time. One-way analysis of variance tests, Bonferroni post hoc tests, independent t tests, and Pearson correlations were utilized with significance determined at the 95% confidence level ( a = 0.05). RESULTS: A total of 148 patients were included in the study. The average fluoroscopy time was 143 ± 67 seconds. Patients with NMS had higher average fluoroscopy times (193 ± 75 s) compared with patients with AIS (129 ± 58 s, P < 0.001). In patients with AIS, fluoroscopy time correlated to the patient's preoperative curve ( r = 0.182, P = 0.050). Patients with AIS with fewer than 12 levels fused had significantly less radiation exposure than those with 12 or more levels fused ( P = 0.01). When controlling for the number of levels fused, patients with AIS with higher BMIs had significantly greater fluoroscopy times ( P = 0.001). In patients with NMS, fluoroscopy time negatively correlated with BMI ( r = -0.459, P = 0.009) and positively correlated with a preoperative curve ( r = 0.475, P = 0.007). CONCLUSION: Fluoroscopy times vary greatly during adolescent spinal fusions for scoliosis. Longer fluoroscopy times are correlated with: NMS diagnosis, larger preoperative curve, BMI, and number of levels fused. Surgeons' knowledge of factors affecting fluoroscopy time will increase awareness and may be the first step in decreasing intraoperative radiation risks. LEVEL OF EVIDENCE: Level III; Therapeutic-a retrospective study.

Five Inhibitory Receptors Display Distinct Vesicular Distributions in Murine T Cells.

T cells can express multiple inhibitory receptors. Upon induction of T cell exhaustion in response to a persistent antigen, prominently in the anti-tumor immune response, many are expressed simultaneously. Key inhibitory receptors are CTLA-4, PD-1, LAG3, TIM3, and TIGIT, as investigated here. These receptors are important as central therapeutic targets in cancer immunotherapy. Inhibitory receptors are not constitutively expressed on the cell surface, but substantial fractions reside in intracellular vesicular structures. It remains unresolved to which extent the subcellular localization of different inhibitory receptors is distinct. Using quantitative imaging of subcellular distributions and plasma membrane insertion as complemented by proximity proteomics and biochemical analysis of the association of the inhibitory receptors with trafficking adaptors, the subcellular distributions of the five inhibitory receptors were discrete. The distribution of CTLA-4 was most distinct, with preferential association with lysosomal-derived vesicles and the sorting nexin 1/2/5/6 transport machinery. With a lack of evidence for the existence of specific vesicle subtypes to explain divergent inhibitory receptor distributions, we suggest that such distributions are driven by divergent trafficking through an overlapping joint set of vesicular structures. This extensive characterization of the subcellular localization of five inhibitory receptors in relation to each other lays the foundation for the molecular investigation of their trafficking and its therapeutic exploitation.

Five inhibitory receptors display distinct vesicular distributions in T cells.

T cells can express multiple inhibitory receptors. Upon induction of T cell exhaustion in response to persistent antigen, prominently in the anti-tumor immune response, many are expressed simultaneously. Key inhibitory receptors are CTLA-4, PD-1, LAG3, TIM3 and TIGIT, as investigated here. These receptors are important as central therapeutic targets in cancer immunotherapy. Inhibitory receptors are not constitutively expressed on the cell surface, but substantial fractions reside in intracellular vesicular structures. It remains unresolved to which extent the subcellular localization of different inhibitory receptors is distinct. Using quantitative imaging of subcellular distributions and plasma membrane insertion as complemented by proximity proteomics and a biochemical analysis of the association of the inhibitory receptors with trafficking adaptors, the subcellular distributions of the five inhibitory receptors were discrete. The distribution of CTLA-4 was most distinct with preferential association with lysosomal-derived vesicles and the sorting nexin 1/2/5/6 transport machinery. With a lack of evidence for the existence of specific vesicle subtypes to explain divergent inhibitory receptor distributions, we suggest that such distributions are driven by divergent trafficking through an overlapping joint set of vesicular structures. This extensive characterization of the subcellular localization of five inhibitory receptors in relation to each other lays the foundation for the molecular investigation of their trafficking and its therapeutic exploitation.

A Comparative Analysis of Revision Surgery Before or After 2 Years After Graduation From Growth-friendly Surgery for Early Onset Scoliosis.

INTRODUCTION: After discontinuation of growth-friendly (GF) surgery for early onset scoliosis, patients are termed graduates: they undergo a spinal fusion, are observed after final lengthening with GF implant maintenance, or are observed after GF implant removal. The purpose of this study was to compare the rates of and reasons for revision surgery in two cohorts of GF graduates: before or after 2 years of follow-up from graduation. METHODS: A pediatric spine registry was queried for patients who underwent GF spine surgery with a minimum of 2 years of follow-ups after graduation by clinical and/or radiographic evidence. Scoliosis etiology, graduation strategy, number of, and reasons for revision surgery were queried. RESULTS: There were 834 patients with a minimum of 2-year follow-up after graduation who were analyzed. There were 241 (29%) congenital, 271 (33%) neuromuscular, 168 (20%) syndromic, and 154 (18%) idiopathic. 803 (96%) had traditional growing rod/vertical expandable titanium rib as their GF construct and 31 (4%) had magnetically controlled growing rod. Five hundred ninety-six patients (71%) underwent spinal fusion at graduation, 208 (25%) had GF implants retained, and 30 (4%) had GF implants removed.In the entire cohort, there were 108/834 (13%) patients who underwent revision surgery. Of the revisions, 71/108 (66%) occurred as acute revisions (ARs) between 0 and 2 years from graduation (mean 0.6 y), and the most common AR indication was infection (26/71, 37%). The remaining 37/108 (34%) patients underwent delayed revision (DR) surgery >2 years (mean 3.8 y) from graduation, and the most common DR indication was implant issues (17/37, 46%).Graduation strategy affected revision rates. Of the 596 patients with spinal fusion as a graduation strategy, 98/596 (16%) underwent revision, compared with only 8/208 (4%) patients who had their GF implants retained, and 2/30 (7%) that had their GF implants removed ( P ≤ 0.001).A significantly higher percentage of the ARs had a spinal fusion as the graduation strategy (68/71, 96%) compared with 30/37 DRs, (81%, P = 0.015). In addition, the 71 patients who underwent AR undergo more revision surgeries (mean: 2, range: 1 to 7) than 37 patients who underwent DR (mean: 1, range: 1 to 2) ( P = 0.001). CONCLUSION: In this largest reported series of GF graduates to date, the overall risk of revision was 13%. Patients who undergo a revision at any time, as well as ARs in particular, are more likely to have a spinal fusion as their graduation strategy. Patients who underwent AR, on average, undergo more revision surgeries than patients who underwent DR. LEVEL OF EVIDENCE: Level III, comparative.

Trends in the Utilization of Implants in Index Procedures for Early Onset Scoliosis From the Pediatric Spine Study Group.

INTRODUCTION: Because of the relative rarity of Early Onset Scoliosis (EOS) cases, patient registries were developed to combine clinical information from multiple institutions to maximize patient care and outcomes. This study examines the history and trends regarding the use of growth-friendly devices for index surgical procedures in EOS patients within the Pediatric Spine Study Group database. METHODS: All index growth-friendly implants were queried from registry inception until October 2020. EOS etiology, device/implant type, and geographic area/institution for each procedure were recorded. RESULTS: From 1994 to 2020, 2786 patients underwent index surgery at a mean age of 6.2±2.9 years. There were 908 traditional growing rods (TGR) (32.3%), 922 vertical expandable prosthetic titanium rib devices (VEPTR) (33.1%), 5 hybrid VEPTR/TGR (0.18%), and 951 magnetically controlled growing rods (MCGR) (34.2%) index implants. Fifty-six different institutions reported an index implant, and 5 accounted for 823 (30%) of the cases during the study period. Institutions in the Northeast accounted for more index implants than other regions of the United States. There was a 40% increase in index implant insertions annually when comparing 1994 (3 implants/1 center) to 2018 (234 implants/56 centers), ( P <0.001). Beginning in 2009, there was a 90.9% decrease in the number of TGR/VEPTR procedures (2009: 156 implants/32 centers; 2019: 22 implants/49 centers P =0.001), and a 479% increase in MCGR (2009: 1 implant/1 center; 2018: 197 implants/34 centers ( P =0.005). The overall number of growth-friendly index procedures performed in 2019 (150/49 centers) decreased 34.5% when compared to 2018 (234/48 centers). CONCLUSION: The number of growth-friendly implants reported in the Pediatric Spine Study Group registry as the initial surgical management of EOS increased markedly over the past 20 years. MCGR is currently the predominant type of device utilized for index surgical procedures by group members, surpassing the use of VEPTR and TGR in 2014. There was a significant decrease in index growth-friendly procedures in 2019 compared to 2018. LEVEL OF EVIDENCE: Level IV.

Pelvic fixation is not always necessary in children with cerebral palsy scoliosis treated with growth-friendly instrumentation.

PURPOSE: A previous study showed that patients with neuromuscular scoliosis who underwent fusion to L5 had excellent coronal curve correction and improvement in pelvic obliquity (PO) when preoperative L5 tilt was < 15°. Our purpose was to identify indications to exclude the pelvis in children with cerebral palsy (CP) scoliosis treated with growing-friendly instrumentation. METHODS: In a retrospective cohort study, children with CP scoliosis treated with TGR, MCGR, or VEPTR with minimum 2-year follow-up were identified from a multicenter database. RESULTS: 27 patients with distal spine anchors (DSA) and 71 patients with distal pelvic anchors (DPA) placed at the index surgery were analyzed. The DSA group had a lower pre-index PO (9° vs 16°, P = 0.0001). Most recent radiographic data were similar except the DSA patients had a smaller major curve (47° vs 58°, P = 0.038). 6 (22%) DSA patients underwent extension of the instrumentation to the pelvis (DSA-EXT), most commonly at final fusion (5 patients). DSA-EXT patients had a higher pre-index L5 tilt than patients who did not require extension (DSA-NO EXT) (19° vs 10°, P = 0.009). Sub-analysis showed a lower major curve at most recent follow-up in the DSA-EXT group compared to the DPA group (33° vs 58°, P = 0.021). The DSA-EXT group had a higher number of complications per patient compared to the DSA-NO EXT group (2.3 vs 1.1, P = 0.029). CONCLUSION: Pre-index L5 tilt ≤ 10° and PO < 10° may be indications to exclude the pelvis in children with CP scoliosis treated with growth-friendly instrumentation. DSA may provide better long-term control of the major curve than DPA.

Baclofen Pump Use: Complications After Growth-friendly Instrumentation for Early-onset Scoliosis.

BACKGROUND: Patients with early-onset scoliosis (EOS) and spasticity may receive treatment with an intrathecal baclofen pump. We assessed how baclofen pumps are associated with the odds of complications and secondary interventions after growth-friendly (GF) spine surgery for EOS and analyzed infectious complications within the pump cohort. METHODS: Using a prospectively maintained, international multicenter database, we studied patients with neuromuscular EOS with baclofen pumps who underwent GF spine surgery from 2002 through 2019 (n=25). Baclofen pumps were implanted before GF instrumentation in 18 patients, during in 2 patients, and after in 5 patients. Patients with existing pumps at initial GF spine surgery were matched 1:3 with 54 patients (control group) without pumps according to treatment center, year of surgery, diagnosis, surgery type, and preoperative curve magnitude. Univariate analysis and multivariate logistic regression were performed to compare complications and secondary interventions between the 2 cohorts. RESULTS: Patients with baclofen pumps had 4.8 times the odds [95% confidence interval (CI): 1.5-16] of experiencing any complication within 1 year after initial GF spine surgery compared with controls. During mean follow-up of 6.9±4.3 years, they had 4.7 times the odds (95% CI: 1.3-16) of deep surgical site infection and 5.6 times the odds (95% CI: 1.2-26) of spinal rod removal after any complication. Differences in rates of mechanical complication, such as rod migration and breakage, were nonsignificant between the 2 groups. For the 9 patients (50%) with pumps who experienced infections, the most common microorganisms were Staphylococcus aureus (4 patients) and Pseudomonas aeruginosa (2). The pump/catheter was revised or removed, in addition to antibiotic therapy or surgical irrigation and debridement, in 2 patients. CONCLUSIONS: Among patients with neuromuscular EOS, those with baclofen pumps are much more likely to experience complications within 1 year after GF spine surgery. They are also more likely to have deep surgical site infections, with S. aureus and P. aeruginosa being the most common causative organisms, and to require spinal rod removal. LEVEL OF EVIDENCE: Level III-retrospective comparative study.

Analysis of Author Gender in the Pediatric Orthopaedic Literature from 2011 to 2020.

INTRODUCTION: Orthopaedic surgery remains a male-dominated specialty. To date there has not been a focused analysis of gender in authorship within the pediatric orthopaedic literature. METHODS: The electronic table of contents from 2011 to 2020 of 3 major pediatric orthopaedic journals [Journal of Children's Orthopaedics (JCO), Journal of Pediatric Orthopaedics (JPO), and Journal of Pediatric Orthopaedics Part B (JPO-B)] were reviewed. Publications were reviewed for the number of articles with at least 1 female author and the number of articles with women listed as first authors. These were compared over the 10-year study period, and by individual year of publication. Statistical analysis included a general linear model with factorial one-way anslysis of variance and Bonferroni post hoc testing. RESULTS: A total of 4097 articles were reviewed. In 2020, there was a significantly higher percentage of articles with a female author when compared with 2011 (64% to 42%, P=0.010). A female was listed as first author in significantly more publications in 2020 as compared with 2011 (23% to 10%, P=0.031). During the 10-year study period, the highest mean proportion of articles with at least 1 female author was seen in JPO (60%), with similar findings in JCO (55%). Significantly fewer articles in JPO-B contained a female author (37%, P=0.001). The highest percentage of publications with a female first author across 10 years was in JCO (22%), followed by JPO (20%). Significantly fewer articles with a female first author were found in JPO-B (9%, P=0.001). CONCLUSION: There is an increasing proportion of publications in the pediatric orthopaedic literature with female authors and female first authors from 2011 to 2020. In addition, there was a statistical difference in female authorship when comparing specific publications, which should be investigated further. LEVEL OF EVIDENCE: Level IV.

A Single Sugar-Tong Splint Can Maintain Pediatric Forearm Fractures.

Displaced pediatric forearm fractures often are treated with closed reduction and immobilization. Recent literature demonstrates no difference in maintaining alignment or needing repeat intervention in patients immobilized with either a single sugar-tong splint or a long-arm cast, but most series include patients with distal fractures. This study included patients 3 to 15 years old who underwent closed reduction and immobilization for displaced midshaft or proximal forearm fractures. Radiographs from the time of injury, after reduction, and at 4-week follow-up were reviewed for coronal and sagittal plane angular alignment. Secondary interventions also were recorded. A total of 121 patients (70 long-arm cast, 51 simple sugar-tong splint) met inclusion criteria. Groups were matched in terms of age (P=.95), sex (P=.41), body mass index (P=.12), and angular deformity prior to reduction in the sagittal (P=.78) and coronal (P=.83) planes. Following closed reduction, sagittal (P=.003) and coronal (P=.002) alignment improved significantly in all patients. At 4-week follow-up, there were no significant differences in sagittal (P=.15) or coronal (P=.68) alignment between the 2 groups. Nine patients underwent a secondary intervention after the index reduction (long-arm cast, n=7; simple sugar-tong splint, n=2), with no statistically significant difference between groups (P=.30). There were no statistically significant differences between patients managed with long-arm cast or simple sugar-tong splint regarding residual sagittal or coronal plane deformity at 4-week follow-up or incidence of secondary intervention. These findings indicate simple sugar-tong splint and long-arm cast appear to be acceptable and equivalent methods of immobilization for these injuries. [Orthopedics. 2021;44(2):e178-e182.].

PD-1 suppresses the maintenance of cell couples between cytotoxic T cells and target tumor cells within the tumor.

The killing of tumor cells by CD8+ T cells is suppressed by the tumor microenvironment, and increased expression of inhibitory receptors, including programmed cell death protein-1 (PD-1), is associated with tumor-mediated suppression of T cells. To find cellular defects triggered by tumor exposure and associated PD-1 signaling, we established an ex vivo imaging approach to investigate the response of antigen-specific, activated effector CD8+ tumor-infiltrating lymphocytes (TILs) after interaction with target tumor cells. Although TIL-tumor cell couples readily formed, couple stability deteriorated within minutes. This was associated with impaired F-actin clearing from the center of the cellular interface, reduced Ca2+ signaling, increased TIL locomotion, and impaired tumor cell killing. The interaction of CD8+ T lymphocytes with tumor cell spheroids in vitro induced a similar phenotype, supporting a critical role of direct T cell-tumor cell contact. Diminished engagement of PD-1 within the tumor, but not acute ex vivo blockade, partially restored cell couple maintenance and killing. PD-1 thus contributes to the suppression of TIL function by inducing a state of impaired subcellular organization.

Minimum 5-Year Follow-up on Graduates of Growing Spine Surgery for Early Onset Scoliosis.

INTRODUCTION: After discontinuation of growth friendly (GF) surgery for early onset scoliosis, patients undergo spinal fusion or continued observation. This last planned treatment is colloquially called "definitive" treatment, conferring these patients as "graduates" of a growing program. The 5-year radiographic and clinical outcomes of this cohort are unknown. METHODS: An international pediatric spine database was queried for patients from a GF program (spine or rib-based) with minimum 5-year follow-up from last planned surgery (GF or spinal fusion). Radiographs and charts were reviewed for main coronal curve angle and maximum kyphosis as well as occurrence of secondary surgery. RESULTS: Of 580 graduates, 170 (29%) had minimum 5-year follow-up (37% male). Scoliosis etiology was congenital in 41 (24%), idiopathic 36 (21%), neuromuscular 51 (30%), and syndromic 42 (25%). Index surgery consisted of spine-based growing rods in 122 (71%) and rib-based distraction in 48 (29%). Mean age at index surgery was 6.8 years, and patients underwent an average of 5.4 lengthenings over an average of 4.9 years (range, 6 mo to 11 y). Last planned treatment was at an average age of 11.8 years (range, 7 to 17 years). Last planned treatment consisted of spinal fusion in 114 patients, 47 had growing implants maintained, 9 had implants removed. Average follow-up was 7.3 years (range, 5 to 13 y).When compared from postdefinitive treatment to 2-year follow-up, there was noted progression of the coronal curve angle (46±19 to 51±21 degrees, P=0.046) and kyphosis (48±20 to 57±25 degrees, P=0.03). However, between 2 and 5 years, no further progression occurred in the coronal (51±21 to 53±21 degrees, P=0.26) or sagittal (57±25 to 54±28 degrees, P=0.93) planes. When stratified based on etiology, there was no significant coronal curve progression between 2- and 5-year follow-up. When comparing spinal fusion patients to those who had maintenance of their growing construct, there was also no significant curve progression.Thirty-seven (21%) underwent at least 1 (average, 1.7; range, 1 to 7) revision surgery following graduation, and 15 of 37 (41%) underwent 2 or more revision surgeries. Reason for revision was implant revision (either GF or spinal fusion) in 34 patients, and implant removal in 3. On an average, the first revision was 2.5 years after the definitive treatment plan (range, 0.02 to 7.4 y). In total, 15 of 37 (41%) revisions occurred over 2 years following the final decision for treatment plan, and 7 of 37 (19%) occurred 5 or more years after the definitive treatment.Patients who underwent spinal fusion as a definitive treatment strategy were more likely to undergo revision surgery (27%) than patients who had their GF implants maintained (11%) (P=0.04). CONCLUSIONS: Five years following "graduation" from growing surgery for early onset scoliosis, there is progression of curve magnitude in both the coronal and sagittal planes up to 2 years, with no further progression at 5 years. A total of 21% of patients undergo at least 1 revision surgery, and average time to revision surgery is over 2 years from last planned surgery. Risk of revision surgery was higher in patients who underwent a spinal fusion as their definitive treatment strategy. LEVEL EVIDENCE: Level III-retrospective comparative. TYPE OF EVIDENCE: Therapeutic.

Prophylaxis for Pediatric Venous Thromboembolism: Current Status and Changes Across Pediatric Orthopaedic Society of North America From 2011.

INTRODUCTION: Pediatric venous thromboembolism (VTE) is a concern for orthopaedic surgeons. We sought to query the Pediatric Orthopaedic Society of North America (POSNA) members on current VTE prophylaxis practice and compare those results with those of a previous survey (2011). METHODS: A 35-question survey was emailed to all active and candidate POSNA members. The survey consisted of questions on personal and practice demographics; knowledge and implementation of various VTE prophylaxis protocols, mechanical and chemical VTE prophylaxis agents, and risk factors; and utilization of scenarios VTE prophylaxis agents for various clinical scenarios. One- and two-way frequency tables were constructed comparing results from the current survey and those of the 2011 survey. RESULTS: Two hundred thirty-nine surveys were completed (18% respondent rate), with most respondents from an academic/university practice reporting one or two partners (>60%). Half were in practice ≥15 years, and >90% reported an almost exclusive pediatric practice. One-third of the respondents reported familiarity with their institution-defined VTE prophylaxis protocol, and 20% were aware of an institutionally driven age at which all patients receive VTE prophylaxis. The most frequently recognized risk factors to guide VTE prophylaxis were oral contraceptive use, positive family history, and obesity. Respondents indicated a similar frequency of use of a VTE prophylaxis agent (either mechanical or chemical) for spinal fusion, hip reconstruction, and trauma (60% to 65%), with lower frequency for neuromuscular surgery (34%) (P < 0.001). One hundred thirty-seven respondents had a patient sustain a deep vein thrombosis, and 66 had a patient sustain a pulmonary embolism. Compared with responses from 2011, only 20 more respondents reported familiarity with their institution VTE prophylaxis protocol (75 versus 55). In 2018, aspirin was used more frequently than in 2011 (52% versus 19%; P < 0.0001) and enoxaparin was used less frequently (20% versus 41%; P < 0.0001). DISCUSSION: Over the past 7 years since the first POSNA survey on VTE prophylaxis, most POSNA members are still unaware of their institution specific VTE prophylaxis protocol. Most respondents agree that either mechanical or chemical VTE prophylaxis should be used for spinal fusion, hip reconstruction, and trauma. The use of aspirin as an agent of chemical VTE prophylaxis has increased since 2011. LEVEL OF EVIDENCE: Level IV. Type of evidence: therapeutic.

Prospectively collected surgeon indications for discontinuation of a lengthening program for early-onset scoliosis.

INTRODUCTION: At some point after children with early-onset scoliosis (EOS) undergo implantation of a distraction construct to control deformity and promote growth, a decision is made to discontinue lengthening. The purpose of this study was to evaluate surgeon indications for discontinuation of a lengthening program and to evaluate patient outcomes. METHODS: As a part of a multicenter database, surgeons prospectively completed a questionnaire at the completion of growth-friendly treatment. Surgeon indications for discontinuation included patient age, pain/functional status, implant status, and spinal deformity parameters. Patient demographics, scoliosis type, deformity parameters, and length of time in a growing program were queried. Patients were treated with a final fusion or observation, and rate of secondary surgeries was analyzed. RESULTS: Questionnaires were completed on 121 patients (61% female). EOS etiology was 31% neuromuscular, 43% congenital, 16% idiopathic, and 10% syndromic. Average age at initiation of growing program was 6.8 ± 3.1 years, and average age at discontinuation was 12.7 ± 2.5 years. The most commonly cited indications for discontinuation of a lengthening program included bone age/skeletal maturity (n = 46), patient age (n = 33), and diminishing returns with expansions (n = 33). A larger coronal Cobb angle was found in patients who underwent definitive fusion (65°) when compared with continued observation (55°, p = 0.001). Twenty-nine (24%) patients were initially treated with observation after completion of a growing construct. In this subgroup, at a minimum of 2 years' (average 3.8 years') follow-up, 26/29 (90%) patients remained stable with observation alone; whereas, three (10%) underwent delayed final fusion surgery. CONCLUSIONS: The most common surgeon-cited indications for discontinuation of a lengthening program in EOS patients are skeletal maturity and patient age. The majority of patients (76%) underwent definitive spinal fusion after discontinuation of a lengthening program; whereas, those treated with observation alone had a survivorship of 90% at a minimum follow-up of two years.

Image-derived models of cell organization changes during differentiation and drug treatments.

PC12 cells are a popular model system to study changes driving and accompanying neuronal differentiation. While attention has been paid to changes in transcriptional regulation and protein signaling, much less is known about the changes in organization that accompany PC12 differentiation. Fluorescence microscopy can provide extensive information about these changes, although it is difficult to continuously observe changes over many days of differentiation. We describe a generative model of differentiation-associated changes in cell and nuclear shape and their relationship to mitochondrial distribution constructed from images of different cells at discrete time points. We show that the model accurately represents complex cell and nuclear shapes and learn a regression model that relates cell and nuclear shape to mitochondrial distribution; the predictive accuracy of the model increases during differentiation. Most importantly, we propose a method, based on cell matching and interpolation, to produce realistic simulations of the dynamics of cell differentiation from only static images. We also found that the distribution of cell shapes is hollow: most shapes are very different from the average shape. Finally, we show how the method can be used to model nuclear shape changes of human-induced pluripotent stem cells resulting from drug treatments.

Learning complex subcellular distribution patterns of proteins via analysis of immunohistochemistry images.

MOTIVATION: Systematic and comprehensive analysis of protein subcellular location as a critical part of proteomics ('location proteomics') has been studied for many years, but annotating protein subcellular locations and understanding variation of the location patterns across various cell types and states is still challenging. RESULTS: In this work, we used immunohistochemistry images from the Human Protein Atlas as the source of subcellular location information, and built classification models for the complex protein spatial distribution in normal and cancerous tissues. The models can automatically estimate the fractions of protein in different subcellular locations, and can help to quantify the changes of protein distribution from normal to cancer tissues. In addition, we examined the extent to which different annotated protein pathways and complexes showed similarity in the locations of their member proteins, and then predicted new potential proteins for these networks. AVAILABILITY AND IMPLEMENTATION: The dataset and code are available at: www.csbio.sjtu.edu.cn/bioinf/complexsubcellularpatterns. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Hemiepiphyseodesis for Juvenile and Adolescent Tibia Vara Utilizing Percutaneous Transphyseal Screws.

BACKGROUND: In juvenile and adolescent tibia vara patients with sufficient growth remaining, implant-controlled hemiepiphyseodesis, or guided growth, can be used to correct deformity. Recent reports have described hardware failure of certain hemiepiphyseodesis implants in overweight patients with tibia vara. We describe our experience using transphyseal screws to correct deformity in this patient population. METHODS: A retrospective chart and radiograph review was conducted on all juvenile and adolescent tibia vara patients who underwent lateral proximal tibial hemiepiphyseodesis using a single transphyseal screw. Charts were queried for preoperative and postoperative mechanical axis deviation, medial proximal tibial angle, lateral distal femoral angle, and postoperative complications or need for further surgery. RESULTS: In total, 14 affected limbs in 9 patients (6 males) who underwent lateral proximal tibial transphyseal screw hemiepiphyseodesis were considered. Average chronologic age at implantation was 10.4 years and average body mass index was 31.7 kg/m. At average 23-month follow-up, the average mechanical axis deviation improved from 46 to 0 mm (P<0.001), and the average medial proximal tibial angle improved from 81 to 92 degrees (P<0.001). No limbs underwent further surgery to correct residual deformity. There were no complications or instances of implant failure associated with the transphyseal screws. CONCLUSIONS: Hemiepiphyseodesis using transphyseal screws is an effective technique to correct deformity in juvenile and adolescent tibia vara patients with sufficient growth remaining. This method can be used safely with few complications and with minimal risk of mechanical failure, even in overweight patients. LEVEL OF EVIDENCE: Level IV-therapeutic.

A rare case of type 2 entrapment of the median nerve after posterior elbow dislocation with MRI and ultrasound correlation.

A 9-year-old boy sustained an ulnohumeral dislocation with a medial epicondyle fracture and experienced incomplete post-traumatic median nerve palsy in addition to post-traumatic stiffness following closed reduction and cast immobilization. When his motor palsy and stiffness did not improve, MRI and ultrasound were obtained, which demonstrated entrapment of the median nerve in an osseous tunnel at the fracture site, compatible with type 2 median nerve entrapment. Subsequently, the patient underwent surgery to mobilize the medial epicondyle and free the median nerve, resulting in improved range of motion, near complete restoration of motor function, and complete restoration of sensory function in the median nerve distribution within 6 months of surgery. Median nerve entrapment, particularly intraosseous, is a rare complication of posterior elbow dislocation and medial epicondyle fracture that may result in significant, sometimes irreversible, nerve damage if there is a delay in diagnosis and treatment. A high degree of clinical suspicion with early imaging is indicated in patients with persistent stiffness or nerve deficits following reduction of an elbow dislocation. Intra-articular entrapment diagnosed on ultrasound has been reported and intraosseous entrapment diagnosed clinically and on MR neurography have been reported; however, to our knowledge, this is the first reported case of intraosseous (type 2) median nerve entrapment clearly visualized and diagnosed on traditional MRI and ultrasound. The use of ultrasound for diagnosing median nerve entrapment is an accurate, accessible, and non-invasive imaging option for patients presenting with suspected nerve entrapment following elbow dislocation.