Influence Of Patient Position Research Articles

Impact of patient position on cystometric parameters in pediatric patients with neurogenic bladder: A prospective study.

Urodynamic studies (UDSs) play a crucial role in evaluating lower urinary tract function in pediatric patients with neurogenic bladder. However, the influence of patient position on urodynamic parameters in this population remains understudied. This study aims to investigate the effect of patient position on urodynamic results in children with neurogenic bladder. A prospective study was conducted with 50 pediatric patients diagnosed with neurogenic bladder. Urodynamic recordings were obtained during a single session, with the first two fillings in the supine position and the third filling in the sitting position. Urodynamic parameters assessed included detrusor overactivity (DO), maximum detrusor pressure (MDP), cystometric bladder capacity (CBC), compliance (C), detrusor leak point pressure (DLPP), and bladder volume at the moment of incontinence (DLPV). Patient position did not significantly influence CBC, DO, C, and DLPV (p > 0.05). However, there were significant differences in MDP and DLPP between the supine and sitting positions (p < 0.05), with higher values observed in the supine position. These findings highlight the importance of considering the patient's position when interpreting urodynamic results and making treatment decisions for children with neurogenic bladder. The higher MDP and DLPP values in the supine position may have clinical implications for assessing upper urinary tract integrity and treatment planning. However, further research is needed to understand the underlying mechanisms and generalize these findings to broader patient populations.

The influence of patient position on ultrasound examination of the sciatic nerve in the popliteal fossa: A cross-sectional study.

Ultrasound-guided popliteal fossa sciatic nerve (PFSN) blocks are performed with patients in the supine, lateral or prone position. No known studies compare the quality of images obtained from each approach. This study examines the quality of supine and prone PFSN ultrasound images. Thirty-eight adult volunteers were sorted into two groups. Five regional anaesthesiologists performed ultrasound examinations of the PFSN on volunteers in supine and prone positions. Popliteal fossa sciatic nerve image quality was analysed with grayscale techniques and peer evaluation. Popliteal fossa sciatic nerve depth, distance from the popliteal crease and time until optimal imaging were recorded. The grayscale ratio of the PFSN vs. the background was 1.83 (supine) and 1.75 (prone) (P = 0.034). Similarly, the grayscale ratio of the PFSN vs. the immediately adjacent area was 1.65 (supine) and 1.55 (prone) (P = 0.004). Mean depth of the PFSN was 1.6 cm (supine) and 1.7 cm (prone) (P = 0.009). Average distance from the popliteal crease to the PFSN was 5.9 cm (supine) and 6.6 cm (prone) (P = 0.02). Mean time to acquire optimal imaging was 36 s (supine) and 47 s (prone) (P = 0.002). Observers preferred supine positioning 53.8%, prone positioning 22.5% and no preference 23.7% of the time. Observers with strong preferences preferred supine imaging in 70.9% of cases. Supine ultrasound examination offered quicker identification of the PFSN, in a more superficial location, closer to the popliteal crease and with enhanced contrast to surrounding tissue, correlating with observer preferences for supine positioning. These results may influence ultrasound-guided PFSN block success rates, especially in difficult-to-image patients.

Influence of patient position in thoracoscopic esophagectomy on postoperative pneumonia: a comparative analysis from the National Clinical Database in Japan.

Two prominent patient positions during thoracoscopic esophagectomy are the left lateral decubitus position (LP) and the prone position (PP). However, whether the patient position during thoracoscopic esophagectomy influences short-term outcomes, especially postoperative pneumonia, remains unclear. We aimed to elucidate the impact of patient position on the occurrence of postoperative pneumonia. We analyzed 9850 patients who underwent oncologic thoracoscopic esophagectomies between 2016 and 2019 from the National Clinical Database. We compared the short-term outcomes between the LP and PP groups, and the primary outcome measure was the incidence of postoperative pneumonia. This study included 2637 (26.8%) and 7213 (73.2%) patients in the LP and the PP groups, respectively. The baseline characteristics of the two groups were well-balanced. Compared with the LP group, the PP group had a longer operative time and less blood loss. There were no significant differences in the incidences of postoperative pneumonia, recurrent laryngeal nerve palsy, anastomotic leakage, severe complications, and reoperation between the groups. Meanwhile, prolonged ventilation and surgery-related mortality occurred more frequently in the LP than in the PP group (P < 0.001 and 0.046, respectively). After multivariable adjustment, the patient position did not significantly influence the incidence of postoperative pneumonia (odds ratio 0.91, 95% confidence interval 0.80-1.04). Although prolonged ventilation and surgery-related mortality occurred more frequently in the LP group than in the PP group, the patient position did not significantly influence the occurrence of postoperative pneumonia.

Indocyanine green fluorescence imaging-guided laparoscopic right posterior hepatectomy.

Laparoscopic right posterior hepatectomy is considered difficult on the basis of the surgery difficulty scoring system. In this study, we evaluated the safety and effectiveness of the technical application of indocyanine green (ICG) fluorescence imaging-guided laparoscopic right posterior hepatectomy. Twenty-six patients who underwent ICG fluorescence imaging-guided laparoscopic right posterior hepatectomy at Hepatobiliary and Pancreatic Surgery Department of Zhongnan Hospital, Wuhan University, from June 2018 to December 2019, were included. The influence of patient position, trocar placement, hepatic inflow occlusion, central venous pressure (CVP), and the ICG fluorescence imaging-guided method were analyzed. In 17 patients, the left lateral position was maintained when the main tumor was in the S7, and in the remaining nine patients, the supine position was maintained with the right side of the body raised when the main tumor was in the S6. Ten patients who underwent preoperative injection of ICG were successfully developed for nonanatomical hepatectomy. Sixteen patients received intraoperative ICG injection for anatomical hepatectomy (2 cases had positive imaging findings, 14 cases had negative imaging findings, and 2 cases had failed imaging findings). All patients underwent the Pringle maneuver during the procedure. Four patients were preset with subhepatic vena cava blocking and one patient with suprahepatic inferior vena cava blocking. CVP was controlled at 3.00 ± 0.63 (mean ± SD) cmH2O. The operative time was 216.14 ± 52.05min, and the bleeding volume was 128.57 ± 75.55ml. Four patients had Clavien-Dindo level I complications, and one had level III complications. Postoperative hospitalization duration was 6.19 ± 1.40days. There were 14 patients with hepatocellular carcinoma, 9 with metastatic liver malignancies, 2 with hepatic hemangioma, 1 with focal nodular hyperplasia of the liver, and 10 with hepatitis B liver cirrhosis. ICG fluorescence imaging guidance could be helpful for the safe implementation of laparoscopic right posterior hepatectomy.

Ellipse method for measuring Liaw\u2019s anteversion of the acetabular component after total hip arthroplasty

BackgroundSeveral cup anteversion measurements for post-operative total hip arthroplasty (THA) surgery have been described. We developed the standardized Liaw’s trigonometric method to eliminate the influence of patient position, which is the most accurate method for cup anteversion measurement. We then developed an ellipse method using the Elliversion software and reported an interobserver error reduction in 2013. In this study, we attempted to apply this ellipse method in the clinic and compared its accuracy with the standard trigonometric version.MethodsIn the present study, we attempted to incorporate the ellipse method with Liaw’s standardized anteversion in the simulated cup position. We measured standardized Liaw’s anteversion for 434 radiographs in the clinic using the ellipse method. Repeated standard deviation (RSD) was calculated for accuracy evaluation. Furthermore, paired t-test was used for comparison with the interobserver and intraobserver errors.ResultsWe found that the standardized Liaw’s anteversion measured using the ellipse method showed lower RSD than the radiographic version. RSD was 0.795 in the standardized Liaw’s anteversion with ellipse method group. The p-values of the paired t-test were all higher than 0.05 when measuring the interobserver and intraobserver errors. It indicated that the ellipse method was a precise and simple tool for cup anteversion measurement.ConclusionWe believe that this ellipse measurement can assist surgeons while placing the acetabulum cup into the precise position and enable early diagnosis of acetabulum loosening.

Influence of patient position and other inherent factors on image quality in two different cone beam computed tomography (CBCT) devices

ObjectivesThe aim of this in vitro study was to evaluate how a deviation from the horizontal plane, affects the image quality in two different CBCT-devices. MethodsA phantom head SK150 (RANDO, The Phantom Laboratory, Salem, NY, USA) was examined in two CBCT-units: Accuitomo 80 and Veraviewepocs 3D R100 (J. Morita Mfg. Corp. Kyoto, Japan). The phantom head was placed with the hard palate parallel to the horizontal plane and tilted 20° backwards. Exposures were performed with different field of views (FOVs), voxel sizes, slice thicknesses and exposure settings. Effective dose was calculated using PCXMC 2.0 (STUK, Helsinki, Finland). Image quality was assessed using contrast-to-noise-ratio (CNR). Region of interest (ROI) was set at three different levels of the mandibular bone and soft tissue, uni- and bilaterally in small and large FOVs, respectively. CNR values were calculated by CT-value and standard deviation for each ROI. Factor analysis was used to analyze the material. ResultsTilting the phantom head backwards rendered significantly higher mean CNR values regardless of FOV. The effective dose was lower in small than in large FOVs and varied to a larger extent between CBCT-devices in large FOVs. ConclusionsHead position can affect the image quality. Tilting the head backward improved image quality in the mandibular region. However, if influenced by other variables e.g. motion artifacts in a clinical situation, remains to be further investigated. Advances in knowledgeImage quality assessed using CNR values to investigate the influence of different patient positions and FOVs.

Influence of patient position and implant material on the stress distribution in an artificial intervertebral disc of the lumbar vertebrae

The aim of this paper was to determine the effect of using cobalt and titanium-based alloys as implant materials for the lumbar vertebrae with an artificial intervertebral disc on the stress distribution. The lumbar vertebrae were chosen for the study because they carry considerably higher loads, especially while standing or sitting. Finite element method (FEM) simulations were conducted for three standard loads reflecting three patient's positions: recumbent, standing and sitting. The FEM analysis was performed using the SolidWorks Simulation module. Artificial units containing a pair of vertebrae with a prosthesis between them were designed by the Solid Edge software, based on micro-computed tomography CT scans of the patient's spine. The implant model was designed with its shape based on the geometry of surrounding vertebrae, consisting of an upper pad, a bottom pad and an insert (intervertebral disc). Two implant material configurations were studied. One involved the use of titanium alloy for the upper and bottom pads, while in the other, these pads were made of cobalt alloy. In both cases, a polyethylene insert was used. The FEM results demonstrate that both material configurations meet the requirements for prosthesis design. In both material configurations, the maximum stresses in each prosthesis element are almost twice higher in a sitting posture than in a recumbent position.

初回人工股関節置換術（THA）時の患者体位のソケット設置に及ぼす影響: 続報

初回人工股関節置換術（THA）時の患者体位のソケット設置に及ぼす影響: 続報

The influence of patient position on withdrawal force of lumbar epidural catheters after total knee arthroplasty: A randomized trial

Study objectiveElderly patients with degenerative knee disease may have accompanying degenerative spine conditions. There are no studies on lumbar epidural catheter withdrawal forces in these patients. The aim of this study was to investigate withdrawal forces and possible associated risk factors in patients undergoing total knee arthroplasty (TKA). DesignProspective randomized trial. SettingOperating room and ward in a university hospital. PatientsSeventy-eight patients aged 65 to 80years who were undergoing TKA and combined spinal epidural anesthesia were enrolled. InterventionsLumbar epidural catheterization was performed in a lateral position before surgery and the patients were randomly allocated to one of 3 positions for removal: flexed lateral (L), prone (P), and sitting (S). On the third postoperative day, the lumbar epidural catheters were removed by a single investigator with the patient in the assigned position. MeasurementsWe measured the peak tension during catheter withdrawal and evaluated the factors affecting peak tension. Main resultsThe forces required to remove the catheters were considerably greater in the sitting and prone than in the flexed lateral position: group P (3.9N [0.28-10.36]), group S (4.1N [0.04-11.57]), and group L (1.3N [0.07-3.65]) (P<.001). There was a positive correlation between the length of catheter in the epidural space and peak tension (P=.0026, β coefficient=.223). ConclusionsFor ease of removal of catheters from the lumbar epidural space, the flexed lateral position is recommended for elderly patients undergoing TKA. When placing the epidural catheter, the physician should be careful not to insert a catheter that is excessively long.

Computerized tomography imaging in adolescent idiopathic scoliosis: prone versus supine.

The aim of the present study was to assess the degree of apical vertebral rotation values in Adolescent Idiopathic Scoliosis (AIS) that were obtained on CT scans, and to analyze the influence of patient position (supine versus prone) on the degree of rotation. The study included 50 apical vertebra rotation measurements of 34 patients with Type 1A and Type 3C curvature according to the Lenke classification. CT imaging was applied to the patients in supine and prone positions to measure the apical vertebral rotation (AVR). The average AVR angles were measured using the Aaro-Dahlborn method and the results were compared. No significant differences were found between the vertebral rotation measured in the prone and supine positions for the Lenke 1A subgroup and the Lenke 3C thoracic group (p = 0.848; p = 0.659, respectively). In the Lenke 3C lumbar group, however, the vertebral rotation in the supine position was found to be significantly lesser than that in the prone position (difference -1.40° ± 1.79°, p = 0.007). The assessment of the apical vertebra rotation is crucial in AIS. Even though the vertebral rotation in the supine position was found to be significantly lesser than that in the prone position, CT imaging in a prone position could not be considered clinically more relevant than the CT images in a supine position as there was less than 3° difference.

The Influence of Patient Positioning in Breast CT on Breast Tissue Coverage and Patient Comfort.

The presented study aimed at optimizing a patient table design for breast CT (BCT) systems with respect to breast tissue coverage and patient comfort. Additionally, the benefits and acceptance of an immobilization device for BCT using underpressure were evaluated. Three different study parts were carried out. In a positioning study women were investigated on an MRI tabletop with exchangeable inserts (flat and cone-shaped with different opening diameters) to evaluate their influence on breast coverage and patient comfort in various positioning alternatives. Breast length and volume were calculated to compare positioning modalities including various opening diameters and forms. In the second study part, an underpressure system was tested for its functionality and comfort on a stereotactic biopsy table mimicking a future CT scanner table. In the last study part, this system was tested regarding breast tissue coverage. Best results for breast tissue coverage were shown for cone-shaped table inserts with an opening of 180 mm. Flat inserts did not provide complete coverage of breast tissue. The underpressure system showed robust function and tended to pull more breast tissue into the field of view. Patient comfort was rated good for all table inserts, with highest ratings for cone-shaped inserts. Cone-shaped tabletops appeared to be adequate for BCT systems and to allow imaging of almost the complete breast. An underpressure system proved promising for the fixation of the breast during imaging and increased coverage. Patient comfort appears to be adequate. Tissue coverage in breast CT is highly dependent on patient table design. An underpressure fixation system shows potential to increase breast coverage. The proposed breast CT patient table design combines good coverage and patient comfort.

Quantitative analysis of regional lung ventilation and perfusion PET with 68Ga-labelled tracers

The aims of this study were to determine the quantitative parameters of ventilation (V) and perfusion (Q) PET scans assessing V/Q quotients in patients with various lung pathologies, as well as the influence of patient position on regional perfusion patterns. Fifty-three patients (24 male and 29 female) underwent lung scintigraphy with (68)Ga-labelled radiopharmaceuticals. (68)Ga Galligas and B20 microspheres used for V and Q imaging were produced in-house. Images were acquired under a standard setup with two emission scans of the whole lung in the supine (S) position (acquisition time 3 min/bed position) on a PET/CT scanner combined with low-dose computed tomography (CT) for attenuation correction. In 27 patients the Q scan was repeated in the prone (P) position. Parametric images were calculated (V/Q, P/S when applicable) for each patient. Patients were grouped according to diagnostic findings, and V/Q ratio distributions were further analysed. Gradients of the regional blood flow in both the supine and prone position were calculated. The results from visual interpretation could be confirmed with parametric images. Voxel-wise V/Q analysis revealed significant differences in descriptive parameters such as median, mean and SD between normal patients and patients with acute and previous pulmonary embolism. Skewness and kurtosis were not significantly different. The effect of gravitation could be demonstrated by significant position-dependent changes of the gradients in the ventral-dorsal and apical-basal directions. PET/CT using (68)Ga-labelled tracers allows the application of quantitative procedures to improve functional pulmonary imaging in clinical diagnosis and research.

The influence of patient position on withdrawal force of thoracic epidural catheters*

We investigated the forces required to remove thoracic epidural catheters to determine the effect of patient position on removal. Eighty-four patients undergoing open thoracotomy and thoracic patient-controlled epidural analgesia were enrolled. Catheterisation was performed under fluoroscopic guidance before surgery, and the patients were allocated to one of three position groups for removal: prone; sitting; and lateral. On the third postoperative day, the peak tension during withdrawal in the assigned position was measured. No differences in mean (SD) forces were found between groups: prone 1.61 (0.39) N, supine 1.62 (0.61) N and lateral 1.36 (0.56) N (p = 0.140). The withdrawal forces required to remove thoracic epidural catheters were not affected by the position. Thus, the position for removal can be determined by patient's choice and clinical judgement.

Influence of Patient Position on Hemodynamic Assessment during Right Heart Catherisation in PAH

Influence of Patient Position on Hemodynamic Assessment during Right Heart Catherisation in PAH

Influence of patient position on socket position in total hip arthroplasty

Influence of patient position on socket position in total hip arthroplasty

Influence of patient position on socket position in total hip arthroplasty

Influence of patient position on socket position in total hip arthroplasty

TH-D-304A-08: Quantitative PET Imaging of Heterogeneous Tumors: The Influence of Patient Position On Recovered Activity

Purpose: Dose‐painting will require precise quantification of uptake within sub‐regions of heterogeneous tumors. We have measured and characterized the effect of patient positioning on heterogeneity within PET images for 2D and 3D acquisition. Methods and Materials: Position‐dependent variations in recovery coefficients (RC) were measured on a multi‐slice PET imaging system using a phantom of five P 18P F‐filled spheres: two10mm and 15mm diameter, one 5mm. Spheres of each size were repositioned in 1mm increments between acquisitions while two kept stationary. 2D and 3D coincident counts were acquired at 4 minutes‐per‐position, and images generated with iterative reconstruction protocols. Measured RC variations were used to calculate expected SUV changes within heterogeneous tumors, for patient positions sampled from distributions of axial, radial, and angular uncertainties associated with head and neck (HN) cancer.Results: For sub‐voxel shifts in axial direction, the peak‐to‐trough RC values (RCBPTB) in 2D mode were 41%, 8% for 5mm and 10mm diameter sub‐regions. In 3D mode, these axial RCBPTB values were 24% and 7%. RCBPTB for radial shifts were 31% and 14% for images acquired in 2D mode, and 37% and 12% for 3D acquisition. All RCBPTB for15mm spheres were within the noise background, as determined from measurements of the stationary spheres.Random adjustments of head position resulted in notable changes in visual appearance and spatial distribution within PET images. For a very heterogeneous HN tumor, estimated population correlation coefficient between images was 0.8 (n = 1000 images × 696 voxels). However, correlation between individual images ranged from 1.0 to 0.6. Conclusion: Reproducibility is necessary for quantitative PET imaging; stable and precise voxel values will result in reliable voxel‐based image analysis. However, sub‐voxel verification of position of tumor sub‐regions is impossible, so shift‐interpolated images, which correspond to more reproducible mean RC values, could potentially reduce this systematic uncertainty.

Correction of Error in Two-dimensional Wear Measurements of Cemented Hip Arthroplasties

The irregularity of individual wear patterns of total hip prostheses seen during patient followup may result partially from differences in radiographic projection of the components between radiographs. A method to adjust for this source of error would increase the value of individual wear curves. We developed and tested a method to correct for this source of error. The influence of patient position on validity of wear measurements was investigated with controlled manipulation of a cadaveric pelvis. Without correction, the error exceeded 0.2 mm if differences in cup projection were as small as 5 degrees. When using the described correction method, cup positioning differences could be greater than 20 degrees before introducing an error exceeding 0.2 mm. For followup of patients in clinical practice, we recommend using the correction method to enhance accuracy of the results.

Incidence of Bradycardia During Recovery From Spinal Anaesthesia: Influence of Patient Position

We administered 0.5% plain bupivacaine 4 ml intrathecally (L2-3 or L3-4) in three groups of 20 patients, according to the position in which they were nursed in the post-anaesthesia care unit (PACU): supine horizontal, 30 degrees Trendelenburg or hammock position (trunk and legs 30 degrees elevated). Patients were observed until anaesthesia descended to less than S1. The incidence of severe bradycardia (heart rate < 50 beat min-1) in the PACU was significantly higher in patients in the Trendelenburg position (60%) than in the horizontal (20%, P < 0.01) or hammock (10%, P < 0.005) position. After 90 min, following admission to the PACU, only patients in the hammock position did not have severe bradycardia. In this late phase, the incidence of severe bradycardia in the Trendelenburg group was 35% (P < 0.005) and 10% in patients in the supine horizontal position. In four patients, severe bradycardia first occurred later than 90 min after admission to the PACU. The latest occurrence of severe bradycardia was recorded 320 min after admission to the PACU. We conclude that for recovery from spinal anaesthesia, the Trendelenburg position should not be used and the hammock position is preferred.

Influence of Patient Position in Myocardial SPECT on the Diagnosis of CHD

Of the study was to show that changing patient position from supine to prone results in improved specificity of myocardial SPECT (MS). We examined the influence of patient position in MS on the diagnosis of coronary heart disease (CHD) in 151 patients. By using a Tc-99m-labeled compound (Tetrofosmin, Myoview, Nycomed, Amersham) examinations could be performed in supine and prone position within 35 minutes. Examinations were performed as a two-day stress-rest protocol with one gamma camera head and 180 degrees rotation without absorption correction. Semi-quantitative patient and heart phantom data show similar values for anterior and inferior wall in prone position in contrast to a lower count ratio of inferior to anterior wall in supine position. This demonstrates the importance of patient position with respect to artifacts specificity. Changing patient position from supine to prone mainly improves diagnostic specificity for CHD in the inferior wall in men (from 58% to 90%) and in the anterior wall in women (from 80% to 93%). Sensitivity is the same for both techniques. Changing patient position from supine to prone significantly improves diagnostic specificity while sensitivity remains unchanged.