Prone Radiographs Research Articles

Does levelling of T1 tilt intra-operatively affect post-operative shoulder balancein adolescent idiopathic scoliosis patients?

Previous studies have shown that T1 tilt is positively correlated with post-operative shoulder balance (SB). The aim of this study was to explore the role of intra-operative T1 tilt, among other shoulder parameters as a potential parameter to predict post-operative SB in adolescent idiopathic scoliosis (AIS) patients. A retrospective review of AIS patients with structural thoracic curves with minimum 2year follow up was conducted from a single tertiary center. Standing pre-operative, 1st erect, 1year and 2-year follow-up; and intra-operative final prone radiographs were reviewed along with clinical data. Patients were stratified into 2 cohorts: Group A-Final intra-operative T1 tilt ≤5° and Group B-Final intra-operative T1 tilt >5°. These groups were compared for post-operative SB as a whole and separately for patients with baseline right or left shoulder high and if UIV was T2 or T3/T4. Patients with optimal SB (Radiographic shoulder height (RSH) <2cm) at 2years were compared to sub-optimal SB (RSH ≥ 2cm) with respect to multiple SB variables. 55 patients (mean age 15.1years-old, 43 F, mean BMI 22, mean thoracic Cobb-49.8°) were included. Based on Lenke curve types, there were 13 patients with type 1A, 10 patients with 1B, 12 patients with 1C, 7 patients with 2A, 4 patients with 2B and 9 patients with type 3C. T1 tilt was significantly correlated with RSH, Clavicle angle difference (CAD), First Rib Angle (FRA), and UIV tilt at first erect, 1-year, and 2-year post-op radiographs (p < 0.05 for all). When comparing groups, A and B, Group A patients showed significantly better restoration of their 2-year SB parameters; RSH (6.8 vs 11.8mm, p = 0.01), CAD (3.9 vs 9.1 p < 0.001) and T1 tilt (4.7 vs 7.8° p = 0.01). Similar results were found for patients with baseline right shoulder high; RSH (p = 0.04), CAD (p < 0.001) and T1 tilt (p < 0.001) and whether UIV was T2 or T3/T4. Eight patients with sub-optimal SB had worse intra-operative T1 tilt (p = 0.03) compared to 47 patients with optimal SB despite no difference in MT Cobb correction (83.1 vs 79.8%, p = 0.57). Post-operative T1 tilt correlates with lateral shoulder parameters at first erect, 1year, and 2-year radiographs. Therefore, T1 tilt can potentially be used as a surrogate to predict post-operative SB. Leveling intra-operative T1 tilt ≤5° is associated with better 2-year post-operative shoulder balance parameters irrespective of whether the UIV was T2 or T3/T4. Patients with sub-optimal SB at 2years had worse final intra-operative T1 tilt despite similar percent correction of main thoracic curve for all patients.

The Effect of Prone and Supine Limb Positioning on the Radiographic Evaluation of Posterolateral Plate Fixation of the Posterior Malleolus.

To facilitate the posterolateral approach to the posterior malleolus patients are often positioned prone initially, then turned supine to complete fixation at the medial malleolus. We sought to define observed differences in the radiographic appearance of implants relative to the joint line, in prone and supine positions. A 3.5mm tubular plate and a 3.5mm posterior distal tibial periarticular plate were applied sequentially to 3 individual cadaveric legs, via a posterolateral approach. The tubular plate was positioned to simulate buttress fixation and the posterolateral plate placed more distally. Each limb was secured on a custom jig and radiographs were taken on a mobile c-arm fluoroscopy machine with a calibration ball. A series of prone AP, supine PA and mortise radiographs were taken. Prone radiographs were also taken in different degrees of caudal tilt to simulate knee flexion which occurs in practice, during intraoperative positioning. Plate tip-joint line distances were measured and Mann-Whitney U tests performed. There was no statistically significant difference in plate tip-joint line distance when comparing equivalent prone and supine views (PA/AP or mortise). However, significant differences in apparent implant position were noted with alterations in caudal tilt. When taking a prone image, when the knee is flexed to 20 degrees, the plate tip will appear 6.5-8.5mm more proximal than in the equivalent supine image where the knee is extended and the fluoroscopy beam is orthogonal to the anatomic axis of the tibia. Observed differences in radiographic appearance of metalwork in the prone and supine position are most likely due to knee flexion and the resulting variation in the angle of the fluoroscopy beam, rather than projectional differences between supine and prone views. Surgeons should be alert to this when analysing intraoperative images.

Can preoperative magnetic resonance imaging be used for sagittal kyphotic flexibility assessment in patients with kyphosis secondary to symptomatic old osteoporotic thoracolumbar fracture?

ObjectiveThis study aimed to investigate whether preoperative magnetic resonance imaging (MRI) can be used for sagittal kyphotic (SK) flexibility assessment in patients with kyphosis secondary to symptomatic old osteoporotic thoracolumbar fracture (so-OTLF).MethodsThe authors evaluated the radiographic data of patients with kyphosis secondary to so-OTLF. All patients underwent posterior corrective fusion surgery in the hospital. Spinal sagittal parameters were measured on standing radiographs preoperatively. The regional kyphosis angle (RKA) was also measured on preoperative supine MRI and intraoperative prone radiographs on the surgical frame. The SK flexibility in patients with kyphosis secondary to so-OTLF was defined as the difference from the RKA measured on the standing radiographs to that measured on the intraoperative prone radiographs or preoperative supine MRI. The difference and the correlation between the SK flexibility measured by these two methods were compared and analyzed.ResultsThirty-seven patients were included. The RKA measured on standing radiographs, supine MRI, and intraoperative prone radiographs were 48.0°, 34.4°, and 32.0°, respectively. Compared with the RKA measured in standing position, the RKA measured on supine MRI decreased by 13.6° (95% confidence interval 11.4°–15.8°), whereas that measured on intraoperative prone radiographs decreased by 16.1° (95% confidence interval 13.7°–18.5°). A linear correlation existed between the SK flexibility measured on supine MRI and that measured on intraoperative prone radiographs, with a mean difference of 2.4° (R2 = 0.912, p < 0.001).ConclusionThe degree of regional kyphosis deformity was reduced by self-reduction of the intraoperative surgical frame. With a predictive value similar to an intraoperative prone radiograph, preoperative supine MRI can be used for SK flexibility assessment in patients with kyphosis secondary to so-OTLF. The ability to predict the intraoperative degree of regional kyphosis deformity with positioning before an operation may help with surgical planning and patient counseling regarding expectations and risks of surgery.

Prone Chest Radiographs: Distinguishing Features and Identification of Support Devices.

PurposeProne position is known to improve acute lung injury, and chest radiographs are often necessary to monitor disease and confirm support device placement. However, there is a paucity of literature regarding radiographs obtained in this position. We evaluated prone radiographs for distinguishing features and ability to identify support devices.MethodsPairs of prone and supine radiographs obtained during the COVID-19 pandemic were assessed retrospectively. IRB approval and waiver of informed consent were obtained. Radiographs were assessed for imaging adequacy, distinguishing features, and support device identification (endotracheal tube, enteric tube, or central line). Radiographs were reviewed by ≥ 2 cardiothoracic radiologists.ResultsRadiographs from 81 patients (63yo ± 13, 30% women) were reviewed. Prone and supine radiographs were comparable for imaging the lung bases (81% vs. 90%, p = 0.35) and apices (93% vs. 94%, p = 1); prone radiographs more frequently had significant rotation (36% vs. 19%, p = 0.021). To identify prone technique, scapula tip located beyond the rib border was 89% sensitive (95%CI 80–95%) and 85% specific (76–92%), and a fundal stomach bubble was 44% sensitive (33–56%) and 90% specific (81–96%). For women, displaced breast shadow was 46% sensitive (26–67%) and 92% specific (73–99%). Prone and supine radiographs each identified > 99% of support devices. Prone exams trended toward increased rate of malpositioned device (12% vs. 6%, p = 0.07).ConclusionScapula position reliably distinguishes prone from supine position; fundal stomach bubble or displaced breast shadow is specific for prone position. Prone radiographs reliably identify line and tube position, which is particularly important as prone patients appear at increased risk for malpositioned devices.

Pre-operative prone radiographs can reliably determine spinal curve flexibility in adolescent idiopathic scoliosis (AIS).

The purpose of this study was to evaluate the correlation between non-effort prone and bending radiographs in determining curve flexibility in adolescent idiopathic scoliosis (AIS). A retrospective review of AIS patients who underwent pre-operative full spine radiographic imaging from 2006 to 2019 was performed. The Cobb angle (CA) of proximal thoracic (PT), main thoracic (MT) and thoracolumbar/lumbar (TL/L) curves were measured and correlated on standing, prone and bending radiographs. Standing, bending, and prone measurements were correlated using Spearman's analysis, and intra-rater reliability was evaluated using intraclass correlation analysis. A total of 381 patients (74% female) with a mean age of 15.1 ± 2.5years were identified. A strong correlation existed between the prone and bending CA for the PT (rs = 0.797, p < 0.01) and MT (rs = 0.779, p < 0.01) curve and a moderate correlation existed between the prone and bending TL/L curve (rs = 0.641, p < 0.01). For a non-structural PT curve, a prone CA < 25° correctly identified a bending CA < 25° 96.7% of the time (p < 0.005). For a non-structural MT curve, a prone CA < 35° correctly identified a bending CA < 25° 90.2% of the time (p < 0.005). For a non-structural TL/L curve, a prone CA < 35° correctly identified a bending CA < 25° 95% of the time (p < 0.005). Prone radiographs demonstrated a moderate to strong correlation with bending radiographs and may be used as a proxy for determining spinal flexibility, especially when bending films are deemed unreliable. III.

Prediction of long-term postoperative results of disc wedge and vertebral tilt with intraoperative prone radiograph in posterior correction of thoracolumbar/lumbar curve in adolescent idiopathic scoliosis: a minimum 5-year follow-up

BACKGROUND CONTEXTPreservation of the more mobile lumbar segments is important during thoracolumbar/lumbar scoliosis surgery; however, the remaining disc wedge angle (DWA) below lowermost instrumented vertebra (LIV) and vertebral body tilt below LIV (LIV+1 tilt) can cause curve progression. PURPOSEThis study aimed to evaluate the efficacy of intraoperative radiograph to predict the postoperative DWA below LIV and LIV+1 tilt on standing radiographs in patients with LIV of L3 or L4. STUDY DESIGN/SETTINGRetrospective cohort study PATIENT SAMPLEA total of 235 patients with idiopathic scoliosis who underwent posterior correction and fusion for the structural thoracolumbar curve and were followed up for >5 years were reviewed. OUTCOME MEASURESDWA below LIV, LIV+1 tilt, Cobb angle, trunk shift, apical vertebra translation, and pelvic parameters were measured. METHODSCorrelation between intraoperative and postoperative measurements of DWA below LIV and LIV+1 tilt were assessed. Additional analysis was performed to identify risk factors and prognosis of LIV+1 tilt ≥10° and DWA below LIV of ≥4° RESULTSLIV+1 tilt measured on intraoperative radiograph was significantly correlated with the postoperative 5-day and postoperative 5-year evaluation in both groups. However, the intraoperative DWA below LIV was only correlated with the postoperative 5-year value in the L3 group (p=.018). At the 5-year follow-up, patients with LIV+1 tilt ≥10° on intraoperative radiography showed significantly greater LIV+1 tilt (p<.001), apical vertebral translation (p<.001), thoracic curve (p=.008), and thoracolumbar curve (p<.001) than patients with LIV+1 tilt <10°. Intraoperative DWA below LIV of ≥4° was only associated with higher DWA below LIV at the 5-year follow-up. CONCLUSIONSIntraoperative measurement of LIV+1 tilt was correlated with long-term postoperative outcomes, and intraoperative LIV+1 tilt ≥10° was associated with a less favorable radiographic outcome. Intraoperative DWA below LIV demonstrated less correlation with postoperative values and was not a prognostic factor for other radiographic parameters.

The Reliability of Pre-operative Prone Radiographs to Determine Spinal Curve Flexibility in Adolescent Idiopathic Scoliosis

Purpose: The Lenke classification requires full spine standing and bending radiographs to evaluate spinal flexibility. Because bending films are inherently variable, pre-operative assessment may also utilize full spine prone imaging that is not effort based. Few studies have addressed the correlation of different radiographic positions, specifically the prone position to the bending position, to assess spinal flexibility. The purpose of this study was to determine if prone position radiographs can be a surrogate for bending position …

The Reliability of Pre-operative Prone Radiographs to Determine Spinal Curve Flexibility in Adolescent Idiopathic Scoliosis

The Reliability of Pre-operative Prone Radiographs to Determine Spinal Curve Flexibility in Adolescent Idiopathic Scoliosis

New Sign of Pneumothorax: Sharp Edge of Aorta on Prone Image

In the prone radiograph, a left pneumothorax may outline part of the upper descending aorta with a sharp interface (similar to the sharp edge of the lateral cardiac margin seen in supine radiographs). The sign is illustrated in a 2 month-old male infant with considerable bilateral lung disease.

Curve flexibility in cerebral palsy-related neuromuscular scoliosis: does the intraoperative prone radiograph reveal more flexibility than preoperative radiographs?

BackgroundSpinal flexibility is determined preoperatively by manipulating the spine and assessing, radiographically, to what extent the amount of deformity reduces. Quantifying spinal flexibility is important when determining the approach to the planned operation in order to achieve the most optimal spinal correction and balance. Currently, supine traction radiography is a popular method used in patients with severe, cerebral palsy-related neuromuscular scoliosis.The different methods for determining spinal flexibility have been studied extensively in the adolescent idiopathic scoliosis population. No such studies exist in the cerebral palsy population. The purpose of this study was to determine how predictive the intraoperative prone radiograph is in determining spinal flexibility in patients with severe, cerebral palsy related neuromuscular scoliosis.  Furthermore, the intraoperative prone radiograph was compared to the preoperatively acquired supine and supine traction radiographs.MethodsTwenty-five consecutive patients with severe, cerebral palsy-related neuromuscular scoliosis were studied. The Cobb angles of the preoperative supine, preoperative supine traction, and intraoperative prone radiograph were measured and compared. The flexibility indices of these radiographs were calculated and compared.Traction was not applied during acquisition of the intraoperative prone radiograph. The radiograph was taken during the exposure to localize surgical levels, prior to instrumentation.ResultsThe supine traction radiograph and the intraoperative prone radiograph had higher flexibility indices than the preoperative supine radiograph. These comparisons were statistically significant. The comparison between the flexibility indices of the supine traction radiograph and intraoperative prone radiograph was not statistically significant.When looking at the preoperative supine traction radiograph separately, it was noted that the process of instrumentation led to 30% more correction of the Cobb angle.ConclusionsThe intraoperative prone radiograph is more predictive of spinal flexibility in patients with severe scoliosis related to cerebral palsy when compared to the preoperative supine radiograph but not the preoperative supine traction radiograph. The preoperative supine traction radiograph serves as the optimal method for determining spinal flexibility in patients with severe, cerebral palsy-related neuromuscular scoliosis.

Is Intraoperative Prone Radiograph Helpful to Predict Radiographic Result for Lenke Type 1 and 3 Patients Treated by Selective Fusion?

Is Intraoperative Prone Radiograph Helpful to Predict Radiographic Result for Lenke Type 1 and 3 Patients Treated by Selective Fusion?

Impact of Prone Surgical Positioning on the Scoliotic Spine

To study the impact of patient-specific prone positioning on the sagittal and coronal curves of scoliotic spines, including the impact of various patient and surgical frame factors. Prone operative positioning has been shown to impact the geometry of various individual spinal segments. Its impact on global spinal geometry and influential factors remains unknown. Lateral and coronal radiographs were acquired of 6 scoliotic patients while standing, prone on a dynamically adjustable surgical frame and intraoperatively on the Relton-Hall frame. Standing lateral bending radiographs were also acquired. Lordosis, kyphosis, and Cobb angles were measured in each position. Personalized finite element models (FEMs), including the spine, ribcage, pelvis, and lower limbs were generated for each patient based on their standing radiographs. The FEM's ability to reproduce prone spinal geometry was evaluated by using different values of intervertebral disc elastic moduli: published, optimized based on lateral bending radiographs and optimized based on prone radiographs. The 6 FEMs were then exploited to study the impact of surgical frame cushion configuration, standing curve magnitudes, and patient weight on spinal geometry changes due to prone positioning. All coronal and sagittal curves decreased in the prone position; averaging 12% in lordosis, 19% in kyphosis, 7%, 14%, and 26%, respectively, for proximal thoracic, main thoracic, and thoracolumbar/lumbar Cobb angles. FEM prone simulations yielded best results when optimized by using the prone position radiographs (Δ<5 degrees for all segmental curves). Lateral bending optimization yielded similar results by using published properties. Surgical frame cushion configuration, standing curve magnitudes, and patient weight all had an important impact on spinal geometries with the exception of thoracic cushion longitudinal position. A strong correlation (R=0.86) was found between standing kyphosis and its reduction in the prone position. Prone positioning results in a reduction of all spinal segmental curves which is dependent on a number of patient and surgical frame factors.

Prone cross-table lateral view: an alternative to the invertogram in imperforate anus.

The prone cross-table lateral radiograph provides equal or sometimes better information, compared to the invertogram, for demonstration of the level of rectal atresia in neonates. Easy positioning, better cooperation of the patient, elimination of the effect of gravity, and better delineation of the rectal gas shadow are the advantages of the prone lateral view. Among the 45 cases compared, equal findings were noted in 37, but in eight babies the level of rectal atresia was more caudal in the prone radiograph than in the invertogram.