Quantitative analysis of diaphragm motion during fluoroscopic sniff test to assist in diagnosis of hemidiaphragm paralysis

Diaphragm dysfunction: how to diagnose and how to treat?

The diaphragm, crucial for respiratory function, is susceptible to dysfunction due to various pathologies that can affect the nervous system, neuromuscular junction or the muscle itself. Diaphragmatic dysfunction presents with symptoms ranging from exertional dyspnoea to respiratory failure, significantly impacting patients' quality of life. Diagnosis involves clinical evaluation complemented by imaging and pulmonary function tests. Chest radiography, fluoroscopy, and ultrasonography are pivotal in assessing diaphragmatic movement and excursion, offering varying sensitivities and specificities based on the type and severity of dysfunction. Ultrasonography emerges as a noninvasive bedside tool with high sensitivity and specificity, measuring diaphragm thickness, thickening fraction, and excursion, and enabling monitoring of disease progression and response to treatment over time. Treatment strategies depend on the underlying aetiology and severity, ranging from conservative management to interventions such as surgical plication or diaphragmatic pacing. Ventilatory support, particularly noninvasive ventilation, plays a pivotal role in treatment, enhancing lung function and patient outcomes across unilateral and bilateral dysfunction. Despite advances in diagnostic techniques, awareness and systematic evaluation of diaphragmatic function remain inconsistent across clinical settings. This review consolidates the current understanding of diaphragmatic dysfunction, highlighting diagnostic modalities and treatment options to facilitate early recognition and management of this entity.

Inspiration Time: The Ultrasound Variable Necessary to Study the Diaphragm Functionality. A Cross-Sectional Controlled Study

Introduction

The diaphragm is considered the main inspiratory muscle, and as such, its assessment is crucial in patients with respiratory pathology. It is known that the contractile capacity of a muscle is determined by strength, length, and the duration of contraction. Although transdiaphragmatic pressure is the gold standard test for its study, ultrasound has been confirmed as a useful tool in clinical practice. Thanks to it, both the strength (diaphragmatic thickness) and the length of movement (diaphragmatic excursion) can be evaluated. This study aims to investigate the relationship between the inspiratory time and the diaphragmatic contraction.

Design

Cross-sectional controlled study.

Methodology

Eighty healthy subjects, yoga practitioners, with no previous respiratory pathology participated in this study. They were asked to take three different types of deep breaths: diaphragmatic with nasal inspiration, pursed-lip inspiration, and ujjayi (nasal inspiration with slight contraction of the glottis). The variables of thickness, excursion, and inspiratory contraction time were taken for each of them by ultrasound.

Results

Diaphragmatic contraction time is the only variable that shows a significant correlation with the other two. Thus, the correlation between inspiratory time and diaphragmatic thickness is significant (p < .001) for the three breaths: diaphragmatic (0.60), ujjayi (0.67), and pursed lips (0.39) and the correlation between inspiratory time and diaphragmatic excursion is significant for diaphragmatic breaths (-0.24, p = .035) and ujjayi (0.27, p = .017), but not in pursed lips (-0.01, p = .90).

Conclusion

The inspiratory contraction time and the diaphragmatic excursion are two essential variables in the dynamic functional evaluation of the diaphragm, compared to the diaphragmatic thickness measurement that only reports its strength.

Enhancing Single-Plane Fluoroscopy: A Self-Calibrating Bundle Adjustment for Distortion Modeling

Single-plane fluoroscopy systems with image intensifiers remain commonly employed in a clinical setting. The imagery they capture is vulnerable to several types of geometric distortions introduced by the system's components and their assembly as well as interactions with the local and global magnetic fields. In this study, the application of a self-calibrating bundle adjustment is investigated as a method to correct geometric distortions in single-plane fluoroscopic imaging systems. The resulting calibrated imagery is then applied in the quantitative analysis of diaphragmatic motion and potential diagnostic applications to hemidiaphragm paralysis. The calibrated imagery is further explored and discussed in its potential impact on areas of surgical navigation. This work was accomplished through the application of a controlled experiment with three separate Philips Easy Diagnost R/F Systems. A highly redundant (~2500 to 3500 degrees-of-freedom) and geometrically strong network of 18 to 22 images of a low-cost target field was collected. The target field comprised 121 pre-surveyed tantalum beads embedded on a 25.4 mm × 25.4 mm acrylic base plate. The modeling process resulted in the estimation of five to eight distortion coefficients, depending on the system. The addition of these terms resulted in 83-85% improvement in terms of image point precision (model fit) and 85-95% improvement in 3D object reconstruction accuracy after calibration. This study demonstrates significant potential in enhancing the accuracy and reliability of fluoroscopic imaging, thereby improving the overall quality and effectiveness of medical diagnostics and treatments.

Bilateral phrenic nerve palsy after posterior cervical decompression and fusion surgery: a rare event after surgery

INTRODUCTION

Delayed C5 weakness is a known entity in cervical spine surgery, although with varied clinical presentation and poorly understood mechanism of action. We describe the first case in the literature of a bilateral C5 palsy leading to bilateral phrenic nerve dysfunction following a posterior cervical decompression and fusion.

CASE REPORT

A 76-year-old male presented with low back pain and was diagnosed as myelopathic. On initial neurological examination, he could not ambulate without assistance and was unsteady on tandem gait. The initial cervical MRI and CT scan showed advanced multilevel degenerative changes of the cervical spine with severe cord compression and myelomalacia. The patient underwent C3-C6 posterior cervical decompression & fusion (PCDF). He awoke with his baseline examination without neurophysiological monitoring changes intraoperatively or C5 root EMG activity. Post-operative MRI of the cervical spine was performed and showed an excellent decompression. The patient was neurologically stable and discharged to a rehabilitation facility. Patient developed a delayed bilateral C5P on postoperative day (POD) 74. Delayed bilateral C5P and phrenic nerve damage was determined to cause this patient's dyspnea. PM&R consult recommended placement of diaphragmatic pacers. However, clinically his respiratory function, as well as motor deficits, have gradually improved.

CONCLUSION

Bilateral diaphragmatic paralysis, a severe complication of cervical spine surgery, may cause respiratory distress and upper limb weakness. C5P, the underlying cause, may arise from various factors. Early detection and management of diaphragmatic weakness with physical therapy and pacers are crucial, emphasizing the need for vigilance by healthcare professionals and surgeons.

Assessment of Diaphragm in Hemiplegic Patients after Stroke with Ultrasound and Its Correlation of Extremity Motor and Balance Function

Background: A variety of functional disorders can be caused after stroke, among which impairment of respiratory function is a frequent and serious complication of stroke patients. The aim of this study was to examine diaphragmatic function after stroke by diaphragm ultrasonography and then to apply to explore its correlation with extremity motor function and balance function of the hemiplegia patients. Methods: This cross-sectional observational study recruited 48 hemiplegic patients after stroke and 20 matched healthy participants. The data of demographic and ultrasonographic assessment of all healthy subjects were recorded, and 45 patients successfully underwent baseline data assessment in the first 48 h following admission, including post-stroke duration, stroke type, hemiplegia side, pipeline feeding, pulmonary infection, ultrasonographic assessment for diaphragm, Fugl−Meyer Motor Function Assessment Scale (FMA Scale), and Berg Balance Scale assessment. Ultrasonographic assessment parameters included diaphragm mobility under quiet and deep breathing, diaphragm thickness at end-inspiratory and end-expiratory, and calculated thickening fraction of the diaphragm. The aim was to analyze the diaphragm function of hemiplegic patients after stroke and to explore its correlation with extremity motor function and balance function. Results: The incidence of diaphragmatic dysfunction under deep breath was 46.67% in 45 hemiplegia patients after stroke at the convalescent phase. The paralyzed hemidiaphragm had major impairments, and the mobility of the hemiplegic diaphragm was significantly reduced during deep breathing (p < 0.05). Moreover, the thickness fraction of hemiplegic side was extremely diminished when contrasted with the healthy control and non-hemiplegic side (p < 0.05). We respectively compared the diaphragm mobility under deep breath on the hemiplegic and non-hemiplegic side of patients with left and right hemiplegia and found there was no significant difference between the hemiplegic side of right and left hemiplegia (p > 0.05), but the non-hemiplegic side of right hemiplegia was significantly weaker than that of left hemiplegia patients (p < 0.05). The diaphragm mobility of stroke patients under quiet breath was positively correlated with age and FMA Scale score (R2 = 0.296, p < 0.05), and significant positive correlations were found between the diaphragm mobility under deep breath and Berg Balance Scale score (R2 = 0.11, p < 0.05), diaphragm thickness at end-inspiratory and FMA Scale score (R2 = 0.152, p < 0.05), and end-expiratory thickness and FMA Scale score (R2 = 0.204, p < 0.05). Conclusions: The mobility and thickness fraction of the hemiplegic diaphragm after stroke by diaphragm ultrasonography were significantly reduced during deep breathing. Diaphragm mobility on bilateral sides of the right hemiplegia patients were reduced during deep breathing. Moreover, the hemiplegic diaphragmatic function was positively correlated with extremity motor and balance function of the hemiplegia patients.