Impact of Maternal Lateral Tilt On Cardiac Output During Caesarean Section Under Spinal Anaesthesia: A Prospective Observational Study

Background: Left uterine displacement (LUD) has been questioned as an effective strategy to prevent aortocaval compression after spinal anesthesia (SA) for cesarean delivery (CD). We tested if LUD has a significant impact on cardiac output (CO) in patients undergoing CD under SA during continuous non-invasive hemodynamic monitoring.Methods: Forty-six patients were included in the final analysis. We considered 4 timepoints of 5 minutes each: T1=baseline with LUD; T2=baseline without LUD; T3=after SA with LUD; T4=after SA without LUD. LUD was then repositioned for CD. Primary outcome was to test if CO decreased from T3 to T4. We also compared CO between T1 and T2 and other hemodynamic variables: mean, systolic and diastolic blood pressure (respectively MAP, SAP and DAP), heart rate (HR), stroke volume (SV), stroke volume variation (SVV), pulse pressure variation (PPV), contractility (dP/dt), dynamic arterial elastance (Eadyn) at the different timepoints. Data on fetal Apgar scores and umbilical arterial and venous pH were collected.Results: CO did not vary from T3 to T4 [CO mean difference -0.02 L/min [95% CI -0.88 to 0.82; p=1]. No significant variation was registered for any variable at any timepoint. Conclusions: LUD did not show a significant impact on CO during continuous hemodynamic monitoring after SA for CD.Trial registration: (retrospectively registered on 03/12/2021) NCT05143684.

Binaural Synthetic Aperture Imaging of the Field of Audition as the Head Rotates and Localisation Perception of Monophonic Sound Listened to through Headphones

A human listening to monophonic sound through headphones perceives the sound to emanate from a point inside the head at the auditory centre at effectively zero range. The extent to which this is predicted by synthetic-aperture calculation performed in response to head rotation is explored. The instantaneous angle between the auditory axis and the acoustic source, lambda, for the zero inter-aural time delay imposed by headphones is 90°. The lambda hyperbolic cone simplifies to the auditory median plane, which intersects a spherical surface centred on the auditory centre, along a prime meridian lambda circle. In a two-dimensional (2-D) synthetic-aperture computation, points of intersection of all lambda circles as the head rotates constitute solutions to the directions to acoustic sources. Geometrically, lambda circles cannot intersect at a point representing the auditory centre; nevertheless, 2-D synthetic aperture images for a pure turn of the head and for a pure lateral tilt yield solutions as pairs of points on opposite sides of the head. These can reasonably be interpreted to be perceived at the sums of the position vectors of the pairs of points on the acoustic image, i.e., at the auditory centre. But, a turn of the head on which a fixed lateral tilt of the auditory axis is concomitant (as in species of owl) yields a 2-D synthetic-aperture image without solution. However, extending a 2-D synthetic aperture calculation to a three-dimensional (3-D) calculation will generate a 3-D acoustic image of the field of audition that robustly yields the expected solution.

Preanesthetic Ultrasonography Assessment of Inferior Vena Cava Diameter in the Supine Position, Left Lateral Tilt Position, and with the Left Uterine Displacement Maneuver in Full-Term Pregnant Women: A Randomized Cross-Over Design Study

BackgroundWe used preanesthetic ultrasonography evaluation to study the effectiveness of left lateral tilt position (LLT) and the left uterine displacement maneuver (LUD) on increasing inferior vena cava diameter (IVCD) in healthy full-term pregnant women, using a randomized, single blinded, cross-over design study.MethodsTwenty-two parturients scheduled for elective cesarean section under spinal anesthesia were recruited. All patients were sequentially placed in the supine position (SPN), LLT and with LUD before induction of spinal anesthesia. Indices of IVCD, measured by subxiphoid ultrasonography, including maximum IVCD (IVCDmax), minimum IVCD (IVCDmin) and collapsibility index (CI), and hemodynamic parameters, such as heart rate and blood pressure, were recorded in each of the postures. Mean or median values of all measurements were compared among the postures.ResultsThe mean values of IVCDmax observed with both LLT and LUD were significantly larger than those in the SPN, respectively (SPN vs. LLT: P <0.05, SPN vs. LUD: P <0.01), although there were no significant differences between IVCDmax with LLT and LUD. There were no significant differences in IVCDmin, CI and hemodynamic parameters between any of the postures. IVCDmax was highest with LUD in 11 patients (55%), in the LLT position in seven patients (35%) and in the SPN in two patients (10%).ConclusionsLLT and LUD might be equally effective in enlarging the narrowed IVCD as compared to SPN. However, both LLT and LUD might not necessarily be appropriate treatment to relieve IVC compression in some cases.Trial registrationThis study was registered in the “UMIN Clinical Trials Registry” (ID no.: 000024344, date. 10th October 2016).

Effect of Maternal Positioning During Cardiopulmonary Resuscitation: A Systematic Review and Meta-analyses

Background: Although rare, cardiac arrest during pregnancy is the leading cause of maternal death. Recently, its incidence has been increasing worldwide because more pregnant women have risk factors. The provision of early, high-quality cardiopulmonary resuscitation (CPR) plays a major role in the increased likelihood of survival; therefore, clinicians should be familiar with its management. Due to the aortocaval compression caused by the gravid uterus, clinical guidelines often emphasise the importance of maternal positioning during CPR, but there has been little evidence regarding which position is most effective.Methods: We searched the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, and OpenGrey (updated on April 3, 2021). We included clinical trials and observational studies with reported outcomes related to successful resuscitations. Results: We included eight studies out of the 1,490 screened. All of these were simulation-based cross-over randomised controlled trials examining the quality of chest compressions. No data were available about the survival rates of mothers or fetuses/neonates. Meta-analyses indicated that resuscitation of pregnant women in the 27°–30° left-lateral tilt position lowered the quality of chest compressions, and the rates of correct compression depth and correct hand position decreased by 17% and 9%, respectively when compared with resuscitation in the supine position. Inexperienced clinicians faced difficulties in performing chest compressions in the left-lateral tilt position. Conclusions: Given that manual left uterine displacement allows the patient to remain supine, the resuscitation of women in the supine position using manual left uterine displacement should continue to be supported. Further research is needed to fill knowledge gaps regarding the effects of maternal positioning on clinical outcomes, such as survival rates following maternal cardiac arrest.

Comparison of Pelvis and Trunk Kinematics Between Youth and Collegiate Windmill Softball Pitchers

Background: The windmill softball pitch is a dynamic sporting movement that places softball pitchers at high risk of injury. Unlike baseball, there is limited research into the mechanical differences between softball pitchers of varying skill levels. Purpose/Hypothesis: The purpose of this study was to compare pelvis and trunk kinematics between youth and collegiate softball pitchers. It was hypothesized that there would be significant differences in pelvis and trunk kinematics between these 2 groups. Study Design: Descriptive laboratory study. Methods: The pelvic and trunk kinematics of 90 softball pitchers were collected during full-effort pitching using a 3-dimensional motion capture system. Participants were grouped based on their age at the time of data collection (35 youth [mean age, 11 ± 1 years]; 55 collegiate [mean age, 20 ± 2 years]). We compared between-group differences in pelvic posterior tilt, lateral tilt, axial rotation, and axial rotation velocity as well as trunk extension, lateral flexion, axial rotation, and axial rotation velocity during the pitching phase between start of pitch and ball release (BR) using 1-dimensional statistical parametric mapping. Statistical significance was determined using Holmes-Šidák stepdown correction–adjusted P values ( P ′). Results: Compared with youth pitchers, collegiate pitchers exhibited a more posteriorly tilted pelvis from the moment of start of pitch until 94% of the way between start of pitch and BR ( P ′ = .002) and a more laterally flexed trunk toward the glove side from the moment of start of pitch until 71% of the way between start of pitch and BR ( P ′ = .010). Conclusion: Collegiate pitchers displayed a more posteriorly tilted pelvis and more laterally flexed trunk toward the glove side during the windmill pitching motion when compared with youth pitchers. Clinical Relevance: These findings add to the growing body of softball research and help elucidate mechanical differences between youth and collegiate softball pitchers.

Lateral Retinaculum Lengthening and Medial Patellofemoral Ligament Reconstruction With Adductor Sling Technique

Background: There are multiple ways of reconstructing the medial patellofemoral ligament (MPFL), including dynamic techniques that fix the graft to the adductor magnus tendon. We present this technique associated to an increasingly common surgery used as adjuvant in some patients with patellar instability, lateral retinaculum lengthening. Indications: Recurrent patellar dislocation with medial laxity and lateral tightness/lateral tilt. Technique Description: This is double bundle MPFL reconstruction with anterior tibialis tendon allograft. Both autograft or allograft may be used, with a minimum length of 15 cm. The graft is fixed to the proximal third of the patella, passing as a sling under the adductor magnus tendon where it is fixed with sutures and returns to the patella. The patellar fixation includes a 10 to 15 mm deep and 4 to 4.5 mm diameter tunnel in the proximal third with suture stitches to the soft tissues in the entrance of the tunnel, plus an anterior periostic tunnel for the second bundle in the proximal third of the patella fixed with suture stitches. Meanwhile, the lateral retinaculum is incised longitudinally into a superficial and deep layer, in order to lengthen it the desired length. Results: The expected outcome of the procedure is to have a stable patellofemoral joint, with patients that gain the lost function and may return to sport without recurrence of patellar dislocation. Discussion/Conclusion: This is a simple, cheap, and reproducible technique that corrects both medial laxity and lateral tightness for patients with recurrent patellar dislocation.

Characterising the Mould Rectification Process for Designing Scoliosis Braces: Towards Automated Digital Design of 3D-Printed Braces

The plaster-casting method to create a scoliosis brace consists of mould generation and rectification to obtain the desired orthosis geometry. Alternative methods entail the use of 3D scanning and CAD/CAM. However, both manual and digital design entirely rely on the orthotist expertise. Characterisation of the rectification process is needed to ensure that digital designs are as efficient as plaster-cast designs. Three-dimensional scans of five patients, pre-, and post-rectification plaster moulds were obtained using a Structure Mark II scanner. Anatomical landmark positions, transverse section centroids, and 3D surface deviation analyses were performed to characterise the rectification process. The rectification process was characterised using two parameters. First, trends in the external contours of the rectified moulds were found, resulting in lateral tilt angles of 81 ± 3.8° and 83.3 ± 2.6° on the convex and concave side, respectively. Second, a rectification ratio at the iliac crest (0.23 ± 0.04 and 0.11 ± 0.02 on the convex and concave side, respectively) was devised, based on the pelvis width to estimate the volume to be removed. This study demonstrates that steps of the manual rectification process can be characterised. Results from this study can be fed into software to perform automatic digital rectification.

Endoscopic endonasal extreme far-medial approach for a lower clivus osteochondroma in a patient with hereditary multiple exostoses: illustrative case

BACKGROUND The authors reported on the use of endoscopic endonasal surgery (EES) for clivus osteochondroma in a patient with hereditary multiple exostoses (HME), a rare pediatric disorder characterized by the formation of osteochondromas adjacent to the growth plates of the axial and appendicular skeletal elements. OBSERVATIONS A 26-year-old man with a family history of HME reported progressive hoarseness and dysphagia over the previous 6 months. He was referred to us after magnetic resonance imaging (MRI) showed a bone tumor in the lower clivus. MRI revealed tumor proliferation in the lower clivus and its extension to the bilateral occipital condyle and jugular tubercle. The hypoglossal canal and jugular foramen were encased on the right side, whereas the medulla oblongata was compressed. The tumor was subtotally resected with EES, and the brainstem was successfully decompressed. The pathological diagnosis was exostoses. Transient postoperative worsening of dysphagia improved within 1 month without other neurological deficits. The patient underwent posterior occipitoaxial fixation 3 months after EES to correct instability and local lateral tilt of the right atlanto-occipital joint. LESSONS The authors’ experience showed that EES is effective for resection of lower clivus osteochondromas, including the cartilaginous cap, and may improve clinical outcomes in patients with HME.