Effect of Severe Distal Tibia, Ankle, and Mid- to Hindfoot Trauma on Meeting Physical Activity Guidelines 18 Months After Injury.

OBJECTIVE: To examine the effect of severe lower extremity trauma on meeting Physical Activity Guidelines for Americans (PAGA) 18 months after injury and perform an exploratory analysis to identify demographic, clinical, and psychosocial factors associated with meeting PAGA. DESIGN: Secondary analysis of observational cohort study. SETTING: A total of 34 United States trauma centers PARTICIPANTS: A total of 328 adults with severe distal tibia, ankle and mid- to hindfoot injuries treated with limb reconstruction (N=328). INTERVENTIONS: None. MAIN OUTCOME MEASURES: The Paffenbarger Physical Activity Questionnaire was used to assess physical activity levels 18 months after injury. Meeting PAGA was defined as combined moderate- and vigorous-intensity activity ≥150 minutes per week or vigorous-intensity activity ≥75 minutes per week. RESULTS: Fewer patients engaged in moderate- or vigorous-intensity activity after injury compared with before injury (moderate: 44% vs 66%, P<.001; vigorous: 18% vs 29%; P<.001). Patients spent 404±565 minutes per week in combined moderate- to vigorous-intensity activity before injury compared with 224±453 minutes postinjury (difference: 180min per week; 95% confidence interval [CI], 103-256). The adjusted odds of meeting PAGA were lower for patients with depression (adjusted odds ratio [AOR], 0.45; 95% CI, 0.28-0.73), women (AOR, 0.59; 95% CI, 0.35-1.00), and Black or Hispanic patients (AOR, 0.49; 95% CI, 0.28-0.85). Patients meeting PAGA prior to injury were more likely to meet PAGA after injury (odds ratio, 2.0; 95% CI, 1.20-3.31). CONCLUSIONS: Patients spend significantly less time in moderate- to vigorous-intensity physical activity after injury. Patients with depression are less likely to meet PAGA. Although the causal relationship is unclear, results highlight the importance of screening for depression.

Construct Validity of Pediatric PROMIS Computerized Adaptive Testing Measures in Children With Adolescent Idiopathic Scoliosis.

BACKGROUND: The use of patient-reported outcome measures, especially Patient-Reported Outcomes Measurement Information System (PROMIS) measures, has increased in recent years. Given this growth, it is imperative to ensure that the measures being used are validated for the intended population(s)/disease(s). Our objective was to assess the construct validity of 8 PROMIS computer adaptive testing (CAT) measures among children with adolescent idiopathic scoliosis (AIS). METHODS: We prospectively enrolled 200 children (aged 10 to 17 y) with AIS, who completed 8 PROMIS CATs (Anxiety, Depressive Symptoms, Mobility, Pain Behavior, Pain Interference, Peer Relationships, Physical Activity, Physical Stress Experiences) and the Scoliosis Research Society-22r questionnaire (SRS-22r) electronically. Treatment categories were observation, bracing, indicated for surgery, or postoperative from posterior spinal fusion. Construct validity was evaluated using known group analysis and convergent and discriminant validity analyses. Analysis of variance was used to identify differences in PROMIS T -scores by treatment category (known groups). The Spearman rank correlation coefficient ( rs ) was calculated between corresponding PROMIS and SRS-22r domains (convergent) and between unrelated PROMIS domains (discriminant). Floor/ceiling effects were calculated. RESULTS: Among treatment categories, significant differences were found in PROMIS Mobility, Pain Behavior, Pain Interference, and Physical Stress Experiences and in all SRS-22r domains ( P <0.05) except Mental Health ( P =0.15). SRS-22r Pain was strongly correlated with PROMIS Pain Interference ( rs =-0.72) and Pain Behavior ( rs =-0.71) and moderately correlated with Physical Stress Experiences ( rs =-0.57). SRS-22r Mental Health was strongly correlated with PROMIS Depressive Symptoms ( rs =-0.72) and moderately correlated with Anxiety ( rs =-0.62). SRS-22r Function was moderately correlated with PROMIS Mobility ( rs =0.64) and weakly correlated with Physical Activity ( rs =0.34). SRS-22r Self-Image was weakly correlated with PROMIS Peer Relationships ( rs =0.33). All unrelated PROMIS CATs were weakly correlated (| rs |<0.40). PROMIS Anxiety, Mobility, Pain Behavior, and Pain Interference and SRS-22r Function, Pain, and Satisfaction displayed ceiling effects. CONCLUSIONS: Evidence supports the construct validity of 6 PROMIS CATs in evaluating AIS patients. Ceiling effects should be considered when using specific PROMIS CATs. LEVEL OF EVIDENCE: Level II, prognostic.

When Is an Isolated Olecranon Fracture Pathognomonic for Osteogenesis Imperfecta?

BACKGROUND: Isolated fractures of the olecranon process of the ulna in pediatric patients with open physes are classically considered pathognomonic for osteogenesis imperfecta (OI). The purpose of this study was to distinguish the clinical manifestations of isolated olecranon fractures in patients with and without OI to help practitioners assess when further evaluation for OI may be necessary. METHODS: All patients younger than 18 years old who were treated for an isolated olecranon fracture at a pediatric tertiary care center between 2009 and 2021 were identified. Patients without radiographs available for review, those with known skeletal dysplasia other than OI, and patients with multiple fractures (eg, polytraumas) or with concomitant dislocations were excluded. Of the 701 patients identified, 403 were included for analysis. Demographic variables, mechanism of injury, treatment type, and determination of OI diagnosis were collected. Patients with a previously confirmed diagnosis of OI or with genetic confirmation of OI following their fracture were designated as OI (+), and the remainder were designated OI (-). The Mann-Whitney U and χ2 tests were used to compare groups. RESULTS: Of the 403 patients, the median age was 7.8 years (interquartile range 5.2 to 12.5), and 270 (67%) were male. There were 14 confirmed cases of OI (3.5%). The OI (+) and OI (-) groups did not differ significantly by age or sex (P>0.05). OI (+) patients were more likely to sustain an injury from low-energy mechanisms (86% vs. 32%, P<0.001), sustain displaced fractures (86% vs. 21%, P<0.001) and undergo operative treatment (86% vs. 20%, P<0.001), and to report a history of previous fracture (79% vs. 16%, P<0.001) than OI (-) patients. 36% of OI (+) patients sustained a second olecranon fracture during the study period; there were no subsequent olecranon fractures in the OI (-) group. CONCLUSIONS: Isolated olecranon fractures may not be pathognomonic for OI. However, orthopaedists must be vigilant about the possibility of OI in patients who sustain displaced, isolated olecranon fractures under low-energy mechanisms with a history of previous fracture(s). LEVEL OF EVIDENCE: Level III.

A Modern Day Timeline for In-Hospital Monitoring in Perfused, Pulseless Pediatric Supracondylar Humerus Fractures.

BACKGROUND: The perfused, pulseless supracondylar humerus fracture (ppSCHF) remains a consistent topic of discussion in the literature. Inpatient observation of these patients postoperatively for worsening vascular exam or compartment syndrome is frequently recommended but not well studied. The purpose of this study was to evaluate the postoperative complications in a cohort of ppSCHF patients and their timeline to discharge. METHODS: This study is a retrospective review of a prospectively maintained database of all operatively treated supracondylar humerus fractures from a tertiary pediatric hospital from 2013 to 2019. All patients without a palpable pulse were included. We excluded patients with <4 weeks follow-up. Demographic, operative, and postoperative data were collected, including time from presentation to operating room (OR), time from OR to discharge, and incidence of postoperative complications, including return to OR, compartment syndrome, new neurovascular deficits, and Volkmann contractures. The descriptive statistics were used to summarize the data. RESULTS: Among 1371 operatively treated supracondylar humerus fractures, 39 (2.8%) presented with a ppSCHF. Five (15%) had a signal on doppler ultrasound, whereas 34 (85%) had no signal. Thirty-seven (95%) patients had a Gartland type III fracture and 2 (5%) had type IV fractures. Twenty-two (56%) patients had a neurological deficit, of which 14 had an anterior interosseous nerve deficit. The average time to OR was 6.9 (range 2.2 to 15) hours; 6 (15%) required open reduction. At the time of discharge, 85% of patients had a palpable pulse and 13% had a dopplerable signal. Postoperatively, no patients were returned to the OR for any secondary procedures. The average length of stay after the operation was 25 (range 8.5 to 40) hours, with 92% of patients being discharged by 36 hours postoperatively. No patients developed compartment syndrome, new neurological deficits, or Volkmann contractures at a mean follow-up of 112 (range 34 to 310) days. CONCLUSIONS: In our study of 39 patients presenting with ppSCHF, no patient required an unexpected return to the OR, or developed post-treatment compartment syndrome, neurological deficits, or Volkmann contractures. The average time from OR to discharge for ppSCHF was 25 hours. LEVEL OF EVIDENCE: Level II.

Time to Completion of Pediatric PROMIS Computerized Adaptive Testing Measures and the SRS-22r in an Adolescent Idiopathic Scoliosis Population.

BACKGROUND: Patient-reported outcome measures are useful tools to quantify patients' pre-treatment and post-treatment symptoms. Historically used "legacy measures", such as the Scoliosis Research Society-22 revised questionnaire (SRS-22r), are often disease-specific and can be time-intensive. Recently developed Patient-Reported Outcomes Measurement Information System (PROMIS) computerized adaptive testing (CAT) measures may reduce administrative burdens and permit more efficient outcome collection within clinic workflows. In an era of medicine where payments are becoming tied to outcomes, we sought to assess the time to completion (TTC) of 8 pediatric PROMIS CAT measures and the SRS-22r in adolescents with idiopathic scoliosis. MATERIALS AND METHODS: Patients presenting to a large, urban tertiary referral hospital were prospectively enrolled into the study. Subjects were first-time survey respondents in various phases and types of treatment for adolescent idiopathic scoliosis. In total, 200 patients ranging from 10 to 17 years old completed 8 Pediatric PROMIS CATs and the SRS-22r. PROMIS CATs administered include Physical Activity, Mobility, Anxiety, Depressive symptoms, Peer Relationships, Physical Stress Experiences, Pain Behavior and Pain Interference. TTC was calculated using start and stop timestamps in the REDCap software. RESULTS: The mean (±SD) TTC for each PROMIS CAT was 1.1 (±0.9) minutes with physical activity, mobility, anxiety, depressive symptoms, peer relationships, physical stress experiences, pain behavior, and pain interference taking 1.2, 1.4, 1.0, 0.9, 1.2, 1.0, 1.0, and 1.2 minutes on average to complete, respectively. Mean TTC for the SRS-22r was 5.2 (±3.0) minutes. CONCLUSIONS: In this pediatric orthopaedic cohort, completion of 8 PROMIS CATs demonstrated minimal test-taker burden and time required for completion. These findings support rapid and easily integrable PROMIS CATs in clinical practice to aid in increased delivery of efficient, patient-centered care. LEVEL OF EVIDENCE: III, cross-sectional study.

Blood glucose monitoring by insulin-treated pilots of commercial and private aircraft: An analysis of out-of-range values.

AIM: To examine blood glucose measurements recorded as part of the diabetes protocol operated by the UK, Ireland and Austria, which allows commercial airline pilots with insulin-treated diabetes to fly. METHODS: An observational study was conducted in pilots with insulin-treated diabetes, granted medical certification to fly commercial or noncommercial aircraft, who recorded pre-flight and hourly in-flight blood glucose measurements. These values were correlated to a traffic light system (green 5.0 to 15.0 mmol/L; amber 4.0 to 4.9 mmol/L and 15.1 to 20.0 mmol/L; and red <4.0 mmol/L or >20.0 mmol/L) and studied for trends in glucose concentrations, time course within flight and any consequences. Pilot demographics were also analysed. RESULTS: Forty-four pilots (90%) recorded one or more blood glucose value outside the green range during the 7 years of the study. Pilot age, diabetes type and duration, and follow-up period were comparable among subgroups, and mean glycated haemoglobin did not differ before and after certification in a way which would indicate poorer glycaemic control in any subgroup. A total of 892 blood glucose values (2.31%) were outside the green range, with half reported in-flight at various time intervals. There were 48 (0.12%) low red range values recorded, 14 (0.04%) of which occurred in-flight; all but four were restored to within the green range by the time of the next measurement. Appropriate corrective action was taken for all out-of-range values, with no reports of pilot incapacitation from any cause. CONCLUSIONS: The traffic light system appears effective in identifying and reducing the frequency and severity of out-of-range values.

Characterization and Ex Vivo evaluation of an extracorporeal high-intensity focused ultrasound (HIFU) system.

BACKGROUND: High-intensity focused ultrasound (HIFU) has been in clinical use for a variety of solid tumors and cancers. Accurate and reliable calibration is in a great need for clinical applications. An extracorporeal clinical HIFU system applied for the investigational device exemption (IDE) to the Food and Drug Administration (FDA) so that evaluation of its characteristics, performance, and safety was required. METHODS: The acoustic pressure and power output was characterized by a fiber optic probe and a radiation force balance, respectively, with the electrical power up to 2000 W. An in situ acoustic energy was established as the clinical protocol at the electrical power up to 500 W. Temperature elevation inside the tissue sample was measured by a thermocouple array. Generated lesion volume at different in situ acoustic energies and pathological examination of the lesions was evaluated ex vivo. RESULTS: Acoustic pressure mapping showed the insignificant presence of side/grating lobes and pre- or post-focal peaks (≤-12 dB). Although distorted acoustic pressure waveform was found in the free field, the nonlinearity was reduced significantly after the beam propagating through tissue samples (i.e., the second harmonic of -11.8 dB at 500 W). Temperature elevation was <10°C at a distance of 10 mm away from a 20-mm target, which suggests the well-controlled HIFU energy deposition and no damage to the surrounding tissue. An acoustic energy in the range of 750-1250 J resulted in discrete lesions with an interval space of 5 mm between the treatment spots. Histology confirmed that the lesions represented a region of permanently damaged cells by heat fixation, without causing cell lysis by either cavitation or boiling. CONCLUSIONS: Our characterization and ex vivo evaluation protocol met the IDE requirement. The in-situ acoustic energy model will be used in clinical trials to deliver almost consistent energy to the various targets.

Entire-spine Magnetic Resonance Imaging Findings and Costs in Children With Presumed Adolescent Idiopathic Scoliosis.

BACKGROUND: Patients with adolescent idiopathic scoliosis (AIS) are commonly monitored for curve progression with spinal radiographs; however, the utility of magnetic resonance imaging (MRI) screening is unclear. The purpose of this study was to assess the findings of screening MRI for patients with a nonsurgical curve size ordered during routine clinical care and compare them with MRI ordered for patients with large curves as part of preoperative screening. METHODS: All consecutive patients with presumed AIS who underwent entire-spine MRI with a presumed diagnosis of idiopathic scoliosis at a single institution between 2017 and 2019 were retrospectively reviewed. Patients were stratified based on MRI indication into the following groups: preoperative evaluation, pain, neurological symptoms, abnormal radiographic curve appearance, rapidly progressive curve, and other. Neural axis abnormalities recorded included concern for tethered spinal cord, syringomyelia, and Chiari malformation. The MRI findings of preoperative patients with large curves were compared with all other patients. The number needed to diagnose (NND) a neurological finding was calculated in patients whose MRIs were ordered during routine clinical care. The amount charged for each patient undergoing entire-spine MRI was determined by review of our institution's Financial Decision Support system. RESULTS: There were 344 patients included in this study with 214 (62%) MRIs performed for preoperative evaluation. Although MRI abnormalities were found in 49% of patients, only 7.0% (24/344) demonstrated neural axis abnormalities with no difference between preoperative and other indications (P=0.37). For patients with nonsurgical curves undergoing MRI due to a complaint of back pain (n=28), there were no neural axis abnormalities, and a lower rate of disk herniation/degenerative changes detected compared with preoperative MRI (3.6% vs. 18%, P=0.06). Among the 15 patients undergoing MRI for a neurological concern, 1 had a neural axis abnormality that required surgical detethering. The NND for MRI to detect a neural axis abnormality that potentially required neurosurgical intervention in nonpreoperative patients with a neurological concern was 34.4. The average cost for MRI was $17,816 (range: $2601 to $22,411) with a total cost of $2,368,439 for nonsurgical curves. CONCLUSIONS: Entire-spine MRI for nonpreoperative indications including pain, abnormal radiographic curve appearance, and rapid curve progression has minimal utility for patients with AIS. For patients with neurological complaints, the NND a potentially treatment-altering finding with MRI is 34.4. LEVEL OF EVIDENCE: Level II-diagnostic.

Characterizing Use of Growth-friendly Implants for Early-onset Scoliosis: A 10-Year Update.

BACKGROUND: Growth-friendly treatment of early-onset scoliosis (EOS) has changed with the development and evolution of multiple devices. This study was designed to characterize changes in the use of growth-friendly implants for EOS from 2007 to 2017. METHODS: We queried the Pediatric Spine Study Group database for patients who underwent index surgery with growth-friendly implants from July 2007 to June 2017. In 1298 patients, we assessed causes of EOS; preoperative curve magnitude; age at first surgery; patient sex; construct type; lengthening interval; incidence of "final" fusion for definitive treatment; and age at definitive treatment. α=0.05. RESULTS: From 2007 to 2017, the annual proportion of patients with idiopathic EOS increased from 12% to 33% (R=0.58, P=0.006). Neuromuscular EOS was the most common type at all time points (range, 33% to 44%). By year, mean preoperative curve magnitude ranged from 67 to 77 degrees, with no significant temporal changes. Mean (±SD) age at first surgery increased from 6.1±2.9 years in 2007 to 7.8±2.5 years in 2017 (R=0.78, P<0.001). As a proportion of new implants, magnetically controlled growing rods increased from <5% during the first 2 years to 83% in the last 2 years of the study. Vertically expandable prosthetic titanium ribs decreased from a peak of 48% to 6%; growth-guidance devices decreased from 10% to 3%. No change was seen in mean surgical lengthening intervals (range, 6 to 9 mo) for the 614 patients with recorded lengthenings. Final fusion was performed in 88% of patients who had undergone definitive treatment, occurring at a mean age of 13.4±2.4 years. CONCLUSIONS: From 2007 to 2017, neuromuscular EOS was the most common diagnosis for patients treated with growth-friendly implants. Patient age at first surgery and the use of magnetically controlled growing rods increased during this time. Preoperative curve magnitude, traditional growing rod lengthening intervals, and rates of final fusion did not change. LEVEL OF EVIDENCE: Level II.

Selenoprotein P and apolipoprotein E receptor-2 interact at the blood-brain barrier and also within the brain to maintain an essential selenium pool that protects against neurodegeneration.

Selenoprotein P (Sepp1) and its receptor, apolipoprotein E receptor 2 (apoER2), account for brain retaining selenium better than other tissues. The primary sources of Sepp1 in plasma and brain are hepatocytes and astrocytes, respectively. ApoER2 is expressed in varying amounts by tissues; within the brain it is expressed primarily by neurons. Knockout of Sepp1 or apoER2 lowers brain selenium from ∼120 to ∼50 ng/g and leads to severe neurodegeneration and death in mild selenium deficiency. Interactions of Sepp1 and apoER2 that protect against this injury have not been characterized. We studied Sepp1, apoER2, and brain selenium in knockout mice. Immunocytochemistry showed that apoER2 mediates Sepp1 uptake at the blood-brain barrier. When Sepp1(-/-) or apoER2(-/-) mice developed severe neurodegeneration caused by mild selenium deficiency, brain selenium was ∼35 ng/g. In extreme selenium deficiency, however, brain selenium of ∼12 ng/g was tolerated when both Sepp1 and apoER2 were intact in the brain. These findings indicate that tandem Sepp1-apoER2 interactions supply selenium for maintenance of brain neurons. One interaction is at the blood-brain barrier, and the other is within the brain. We postulate that Sepp1 inside the blood-brain barrier is taken up by neurons via apoER2, concentrating brain selenium in them.

How do implants overlying the spine influence "The Law of Diminishing Returns" in early-onset scoliosis patients?

PURPOSE: The "law of diminishing returns" (LODR) in early-onset scoliosis (EOS) is well-known. We hypothesized that previously observed variations between constructs may be related to the lateral distance that each construct lies from the spine. We therefore sought to determine whether the curve magnitude improvement and spinal length gains for distraction-based constructs in EOS are positively correlated with the collinearity of the spine and the convex-sided implant on posteroanterior radiographs. METHODS: A prospectively-collected, multicenter EOS registry was queried for all patients who underwent non-fusion, distraction-based instrumentation surgery. Post-index radiographs were graded from 1 to 5 based on amount of overlap between the convex-sided rod and the apical vertebra. Grade 1: convex rod is lateral to convex-sided pedicle; Grade 2: overlaps the convex-sided pedicle; Grade 3: lies between pedicles; Grade 4: overlaps concave-sided pedicle; Grade 5: medial to concave-sided pedicle. ANOVA assessed the correlations between post-index overlap grade and change in (a) curve magnitude and (b) T1-T12 height. Multivariable regression modeling further assessed these associations. RESULTS: 284 patients met all selection criteria and were included. On ANOVA, post-index grade was associated with curve magnitude (p <0.001) and T1-12 height (p = 0.028) change. Better curve correction and height change were associated with higher grade. On regression modeling, curve correction (R = 0.574) and T1-T12 height change (R = 0.339) remained significantly associated with grade when controlling for time, anchor locations, age, underlying diagnosis, and pre-index curve magnitude. CONCLUSION: More apical overlap by the convex rod was associated with better spinal deformity control and improved height gain. LEVEL OF EVIDENCE III: Therapeutic.

Case report: vertebral body tethering for idiopathic scoliosis in a patient with bilateral phocomelia.

PURPOSE: The purpose of this study is to present a case report of a patient with bilateral upper extremity phocomelia with progressive scoliosis, who underwent vertebral body tethering (VBT). METHODS: This is a case report on the use of VBT in a patient with scoliosis and bilateral congenital phocomelia, with 5 year follow-up. RESULTS: A male patient with bilateral phocomelia had early onset scoliosis that progressed to 45° at age 10. Surgical options were discussed, including traditional VBT, posterior spinal fusion, growing rods, magnetically controlled growing rods, and vertical expandible prosthetic titanium ribs. These options would limit the flexibility of the spine. Given these pitfalls, VBT was chosen, as it would address the scoliosis while maintaining trunk flexibility. Preoperatively, he had 45° right main thoracic curve, bending to 22°; he was Risser 0 with open triradiate cartilage. He underwent T6-T11 thoracoscopic VBT, with postoperative correction to 37°. Postoperatively, the patient was able to continue to use his lower extremities for writing, feeding, and personal grooming. He had no postoperative complications. At 3 years, his curve was 21°, and at 5 years was 19°. CONCLUSION: This case describes a novel technique for treating scoliosis in patients with bilateral phocomelia. Other forms of scoliosis surgical treatment limit motion of the spine. Due to this, we present VBT as an option for this unique set of patients for correcting scoliosis, while also preserving trunk flexibility for its role in feeding and self-care.

Rib-to-spine and rib-to-pelvis magnetically controlled growing rods: does the law of diminishing returns still apply?

PURPOSE: The Law Of Diminishing Returns (LODR) has been demonstrated for traditional growing rods, but there is conflicting data regarding the lengthening behavior of Magnetically Controlled Growing Rods (MCGR). This study examines a cohort of patients with early-onset scoliosis (EOS) with rib-to-spine or rib-to-pelvis-based MCGR implants to determine if they demonstrate the LODR, and if there are differences in lengthening behaviors between the groups. METHODS: A prospectively collected multicenter EOS registry was queried for patients with MCGR with a minimum 2-year follow-up. Patients with rib-based proximal anchors and either spine- or pelvis-based distal anchors were included. Patients with non-MCGR, unilateral constructs, < 3 lengthenings, or missing > 25% datapoints were excluded. Patients were further divided into Primary-MCGR (pMCGR) and Secondary-MCGR (sMCGR). RESULTS: 43 rib-to-spine and 31 rib-to-pelvis MCGR patients were included. There was no difference in pre-implantation, post-implantation and pre-definitive procedure T1-T12 height, T1-S1 height, and major Cobb angles between the groups (p > 0.05). Sub-analysis was performed on 41 pMCGR and 19 sMCGR rib-to-spine patients, and 31 pMCGR and 17 sMCGR rib-to-pelvis patients. There is a decrease in rod lengthenings achieved at subsequent lengthenings for each group: rib-to-spine pMCGR (rho = 0.979, p < 0.001), rib-to-spine sMCGR (rho = 0.855, p = 0.002), rib-to-pelvis pMCGR (rho = 0.568, p = 0.027), and rib-to-pelvis sMCGR (rho = 0.817, p = 0.007). Rib-to-spine pMCGR had diminished lengthening over time for idiopathic, neuromuscular, and syndromic patients (p < 0.05), with no differences between the groups (p > 0.05). Rib-to-pelvis pMCGR neuromuscular patients had decreased lengthening over time (p = 0.01), but syndromic patients had preserved lengthening over time (p = 0.65). CONCLUSION: Rib-to-spine and rib-to-pelvis pMCGR and sMCGR demonstrate diminished ability to lengthen over subsequent lengthenings.

Preoperative MRI Reliably Predicts Pedicle Dimensions on Intraoperative CT Images in Structural Main Thoracic Curves in Patients With Adolescent Idiopathic Scoliosis.

STUDY DESIGN: A retrospective comparative study. OBJECTIVE: The aim of this study was to compare the length and diameter of thoracic pedicles in patients with adolescent idiopathic scoliosis (AIS) as measured on preoperative magnetic resonance imaging (pMRI) to intraoperative computed tomography (iCT) scan. SUMMARY OF BACKGROUND DATA: Optimally sized pedicle screw placement during instrumented posterior spinal fusion for AIS can maximize correction and minimize screw pullout. While iCT-guided navigation can quickly estimate screw position and size, this technology is not universally available. Many surgeons utilize pMRI, when obtained, to estimate screw sizes. Data comparing these measurements on pMRI and iCT is limited. We hypothesized that in patients with surgical magnitude AIS, pedicle length, and diameter measured on pMRI would have at least moderate reliability compared to those made on iCT images. MATERIALS AND METHODS: The pMRI and iCT for 60 patients with structural thoracic curves who underwent posterior spinal fusion for AIS at a single center between 2009 and 2017 were analyzed. Bilateral T5-T12 vertebral levels were evaluated for pedicle chord length and pedicle isthmic diameter on both pMRI and iCT. Between-study reliability and interrater reliability was evaluated for each level of the thoracic spine. RESULTS: There is good reliability for pedicle length [intraclass correlation coefficient (ICC)=0.8, 95% confidence interval (CI): 0.78-0.83] and diameter (ICC=0.86, 95% CI: 0.84-0.88) between pMRI and iCT. When assessed by level, T6 has the lowest reliability for length (ICC=0.52, 95% CI: 0.33-0.67) and diameter (ICC=0.55, 95% CI: 0.35-0.69). Interrater reliability ranged from moderate-to-good reliability for all pedicle measurements for both length and diameter on pMRI and iCT. CONCLUSION: Pedicle measurements made on pMRI may be used with reasonable reliability to predict pedicle dimensions visualized on iCT, allowing surgeons to preoperatively plan pedicle screw sizes based off magnetic resonance imaging.

Physiological Effects of Centrifuge-Simulated Suborbital Spaceflight.

BACKGROUND: High-G acceleration experienced during launch and re-entry of suborbital spaceflights may present challenges for older or medically susceptible participants. A detailed understanding of the associated physiological responses would support the development of an evidence-based medical approach to commercial suborbital spaceflight.METHODS: There were 24 healthy subjects recruited into 'younger' (18-44 yr), 'intermediate' (45-64 yr) and 'older' (65-80 yr) age groups. Cardiovascular and respiratory variables were measured continuously during dynamic combinations of +Gx (chest-to-back) and +Gz (head-to-foot) acceleration that simulated suborbital G profiles for spaceplane and rocket/capsule platforms. Measurements were conducted breathing air and breathing 15% oxygen to simulate a cabin pressure altitude of 8000 ft.RESULTS: Suborbital G profiles generated highly dynamic changes in heart rate, blood pressure, and cardiac output. G-induced hypoxemia was observed, with minimum arterial oxygen saturation < 80% in a quarter of subjects. Increased age was associated with greater hypoxemia and reduced cardiac output responses but did not have detrimental cardiovascular effects. ECG changes included recurrent G-induced trigeminy in one individual. Respiratory and visual symptoms were common, with 88% of subjects reporting greyout and 29% reporting blackout. There was one episode of G-induced loss of consciousness (G-LOC).DISCUSSION: Suborbital acceleration profiles are generally well tolerated but are not physiologically inconsequential. Marked hemodynamic effects and transient respiratory compromise could interact with predisposing factors to precipitate adverse cardiopulmonary effects in a minority of participants. Medically susceptible individuals may benefit from expanded preflight centrifuge familiarization that includes targeted physiological evaluation in the form of a 'G challenge test'.Smith TG, Pollock RD, Britton JK, Green NDC, Hodkinson PD, Mitchell SJ, Stevenson AT. Physiological effects of centrifuge-simulated suborbital spaceflight. Aerosp Med Hum Perform. 2022; 93(12):830-839.

Outcomes of Patients With Large Versus Small Bone Defects in Open Tibia Fractures Treated With an Intramedullary Nail: A Descriptive Analysis of a Multicenter Retrospective Study.

OBJECTIVES: To compare outcomes in patients with open tibia shaft fractures based on defect size. DESIGN: Retrospective review. SETTING: Eighteen trauma centers. POPULATION: The study included 132 patients with diaphyseal tibia bone defects >1 cm and ≥50% cortical loss treated with intramedullary nail. OUTCOMES: The primary outcome was number of secondary surgeries to promote healing (bone graft, revision fixation, or bone transport). Additional outcomes included occurrence of secondary surgeries (bone graft, infection, amputation, and flap failure) and proportion healed at one year. Results are compared by "radiographic apparent bone gap" of <2.5 or ≥2.5 cm. RESULTS: The estimated conditional probability of bone grafting within one year given graft-free at 90 days was 44% and 47% in the <2.5 cm and ≥2.5 cm groups, respectively. An estimated infection risk of 14% was observed in both groups [adjusted hazard ratio (HR) 0.98, 95% confidence interval (CI): 0.33-2.92], estimated amputation risk was 9% (<2.5 cm) and 4% (≥2.5 cm) (unadjusted HR 0.66, 95% CI: 0.13-3.29), and estimated flap failure risk (among those with flaps) was 10% and 13%, respectively (unadjusted HR 1.71, 95% CI: 0.24-12.25). There was no appreciable difference in the proportion healed at one year between defect sizes [adjusted HR: 1.07 (95% CI, 0.63-1.82)]. CONCLUSIONS: Larger size bone defects were not associated with higher number of secondary procedures to promote healing or a lower overall one-year healing rate. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Lengthening Behavior of Magnetically Controlled Growing Rods in Early-Onset Scoliosis: A Multicenter Study.

BACKGROUND: The "law of diminishing returns" is described for traditional growing rods. Magnetically controlled growing rods (MCGRs) have become a preferred implant for the surgical treatment of early-onset scoliosis (EOS). We examined a large cohort of patients with EOS to determine whether the law of diminishing returns applies to MCGRs. METHODS: A prospectively collected, multicenter registry was queried for patients with EOS treated with MCGRs. Patients with only spine-based implants and a minimum of 2 years of follow-up were included; patients with congenital scoliosis, single rods, <3 lengthenings, or >25% missing data were excluded. Patients were analyzed in 3 cohorts: primary MCGR (pMCGR) had first-time MCGR implants, secondary MCGR (sMCGR) were converted from an MCGR to a new MCGR, and conversion MCGR (cMCGR) were converted from a non-MCGR implant to MCGR. RESULTS: A total of 189 patients in the pMCGR group, 44 in the cMCGR group, and 41 in the sMCGR group were analyzed. From post-MCGR placement to the most recent follow-up or pre-definitive procedure, there were no differences in the changes in major Cobb angle, T1-S1 height, or T1-T12 height over time between the pMCGR and cMCGR groups. There was a decrease in length achieved at subsequent lengthenings in all cohorts (p < 0.01), and the sMCGR group had a significantly poorer ability to lengthen at each subsequent lengthening versus the pMCGR and cMCGR groups (p < 0.02). The 1-year survival rate was 90.5% for pMCGR, 84.1% for sMCGR, and 76.4% for cMCGR; 2-year survival was 61.5%, 54.4%, and 41.4%, respectively; and 3-year survival was 37.6%, 36.7%, and 26.9%, respectively. Excluding MCGRs still expanding, 27.6% of pMCGRs, 8.8% of sMCGRs, and 17.1% of cMCGRs reached the maximum excursion. Overall, 21.7% reached the maximum excursion. Within the pMCGR cohort, idiopathic and neuromuscular etiologies had a decline in lengthening achieved over time (p < 0.001), while syndromic EOS demonstrated a preserved ability to lengthen over time (p = 0.51). When the etiological groups were compared with each other, the neuromuscular group had the least ability to lengthen over time (p = 0.001 versus syndromic, p = 0.02 versus idiopathic). CONCLUSIONS: The MCGR experiences the law of diminishing returns in patients with EOS. We found that only 21.7% of rods expanded to within 80% of the maximum excursion. LEVEL OF EVIDENCE: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Prevalence of cardiovascular disease risk factors among UK commercial pilots.

AIM: This study is one of the largest ever completed to examine the prevalence of cardiovascular disease (CVD) risk factors among commercial aircrew. METHOD AND RESULTS: A retrospective cross-sectional study comparing prevalence of CVD risk factors age, body mass index (BMI), overweight and obesity, current smoking status, hypertension, and diabetes among commercial aircrew and the UK general population. A total of 14,379 subject records were eligible for the study. The age-sex group mean BMI was significantly lower in almost all pilot age groups compared to the general population. Overweight age-sex group prevalence was significantly higher in the <25, 35-44, 45-54, 55-64 age groups for male pilots, and lower for female pilots in the 25-34 and 45-54 age groups. Male and female pilots had significantly lower age-sex-group prevalence of obesity and current smoking compared to the general population. For hypertension, the male <25 and 35-44 year age groups had significantly higher prevalence, and the 45-54 and 55-64 year age groups had significantly lower prevalence than the general population. Age-standardised mean BMI and prevalence of overweight and hypertension were not significantly different from the highest income quintile of the general population. Age-standardised obesity and current smoking prevalence were significantly lower in pilots compared to the highest socio-economic quintile of the general population. CONCLUSION: Even when comparisons were made with the highest income quintile of the general population to control for socio-economic status, pilots had a significantly lower prevalence of obesity and smoking. This finding is consistent with a strong 'healthy worker effect'.

Syncope in Commercial Pilots and New Regulatory Guidance.

INTRODUCTION: Syncope is both incapacitating and unpredictable, presenting a significant challenge in aircrew assessment. Previous UK Civil Aviation Authority (CAA) guidance lacked transparency and relied heavily on specialist in-house cardiology and neurology opinion. A new algorithm was developed which elaborated and formalized the decision-making process. An analysis of its impact on historic cases was undertaken to ensure it aligned with previous certificatory outcomes.METHODS: The medical literature on syncope and the approaches of other national aviation authorities were reviewed to help inform the development of a new algorithm. Using syncope cases in the CAA database, regulatory outcomes generated using the new algorithm were compared with previous decisions in terms of time off from flying (TOF) and Operational Multi-Crew Limitation (OML) duration.RESULTS: There were 40 historic syncope cases (25 existing certificate holders,15 initial applicants) which were reassessed using the new algorithm. The mean TOF for existing pilots using the new algorithm was 7.1 9.8 (mean SD) vs. 4.2 3.5 mo under the old guidance with an OML duration of 21.4 34.9 vs. 24.5 25.2 mo. One less initial applicant experienced a delay to certification. Four cases with underlying pathology were detected using old and new guidance.DISCUSSION: The reassessment of cases showed no statistically significant difference in TOF and OML duration; this is a positive finding from a regulatory perspective, enabling algorithm-led decision-making with less reliance on in-house expertise. A similar approach may be useful in future updates to other areas of regulatory practice.Anderton RA, Mitchell SJ, ONunain SS. Syncope in commercial pilots and new regulatory guidance. Aerosp Med Hum Perform. 2021; 92(8):642649.

Morphometric analysis of the proximal thoracic pedicles in Lenke II and IV adolescent idiopathic scoliosis: an evaluation of the feasibility for pedicle screw insertion.

PURPOSE: Pedicles on the concave side of the proximal thoracic (PT) curve in adolescent idiopathic scoliosis (AIS) patients with Lenke II and IV deformities tend to be narrow and dysplastic, making pedicle screw (PS) insertion challenging. The aim of this study was to evaluate the feasibility for PS placement in these patients using pedicle chord length, diameter, and channel morphology. METHODS: In this retrospective study, 56 consecutive AIS patients with Lenke II or IV curves who underwent instrumented posterior spinal fusion (PSF) were studied. The mean age at surgery was 14.8 years and the mean PT curve measured 45°. Two independent investigators evaluated all visible pedicles from T1 to T6 vertebral levels using axial images from intraoperative computed tomography-guided navigation recording the pedicle: (1) maximum transverse diameter 'd' at the isthmus, (2) maximum chord length 'l', and (3) qualitative assessment of the channel morphology (types A-D). RESULTS: Two hundred and sixty-eight concave and 264 convex pedicles were measured. The mean 'd' of the concave pedicles at T3 and T4 was < 3.0 mm, compared to > 5.0 mm for the convex counterparts (p < 0.001). Of all concave pedicle channels, 48% had morphology characteristics that were riskier for PS cannulation (type C or D) compared to 2% of all convex pedicle channels (type A or B) (p < 0.001). CONCLUSION: Almost half of all concave pedicles have morphologic characteristics that make them too small to accommodate a PS. Though PSs could be inserted using an in-out-in technique in these patients, alternative fixation anchors may improve strength and safety.