Research on the deposition of inhalable particles in the alveoli of the lungs is important to the causes, development for common respiratory diseases such as emphysema, and even the optimization of clinical treatment and prevention programs of them. In this paper, an in vitro experimental model was established to simulate the deposition of terminal bronchioles and pulmonary acinus particles. The deposition rate of inhalable particles with different particle sizes in the pulmonary acinus was studied under different functional residual capacity. The results showed that the particle diameter was an important factor affecting the deposition of particles in the lung alveoli. Particles with 1 μm diameter had the highest deposition rate. With the functional residual capacity increasing, particulate deposition rate significantly reduced. The results of this study may provide data support and optimization strategy for target inhalation therapy of respiratory diseases such as emphysema and pneumoconiosis. The established model may also provide a feasible in vitro experimental model for studying the deposition of inhalable particles in the pulmonary alveoli.
The inhalation and deposition of particles in human pulmonary acinus region can cause lung diseases. Numerical simulation of the deposition of inhaled particles in the pulmonary acinus region has offered an effective gateway to the prevention and clinical treatment of these diseases. Based on some important affecting factors such as pulmonary acinar models, model motion, breathing patterns, particulate characteristics, lung diseases and ages, the present research results of numerical simulation in human pulmonary acinus region were summarized and analyzed, and the future development directions were put forward in this paper, providing new insights into the further research and application of the numerical simulation in the pulmonary acinus region.
Research on the deposition of inhaled particles in human pulmonary acinus region is important to the pathogenesis investigation, prevention and treatment of lung diseases. Most of the current research focus on the final deposition fraction of inhaled particles in human acinar region, but little is involved in their dynamic deposition characteristics. In this paper, five multi-alveolar models, G3−G7, were built. The evaluation parameter 1/4 deposition time was introduced to study the particle deposition speed. The deposition characteristics of particles in the diameter ranging 0.1−5 μm were numerically simulated and summarized under the influence of factors such as the generation and structure of model, particle diameter and respiratory mode, shedding some new light on the further research of transport of inhaled particles. The results showed that the generation and structure of model had a significance effect on the deposition of particles. 0.1 μm particles were dominated by Brownian diffusion, which experienced a high deposition fraction, a fast deposition speed and a logarithmic deposition curve, while 5 μm particles were dominated by gravitational sedimentation, with a high deposition fraction, a fast deposition speed and an S-shaped deposition curve. The deposition of 0.3−1 μm particles were influenced greatly by convention and varied with the change of respiratory mode. The research methods and results in this paper can provide theoretical basis and data support for the further exploration of the mechanism, prevention and treatment of lung diseases.
Objective To compare the clinical and radiological outcomes of unilateral biportal endoscopic transforaminal lumbar interbody fusion (UBE-TLIF) and minimally invasive tubular TLIF (MT-TLIF) in treatment of lumbar degenerative diseases. Methods A clinical data of 75 patients with lumbar degenerative diseases, who met the selection criteria between August 2019 and August 2020, was retrospectively analyzed, including 35 patients in the UBE- TLIF group and 40 patients in the MT-TLIF group. There was no significant difference in general data such as gender, age, body mass index, disease type and duration, and surgical segment between the two groups (P>0.05), which was comparable. The operation time, intraoperative blood loss, hemoglobin (Hb) before operation and at 1 day after operation, the length of hospital stay, incidence of complications, and visual analogue scale (VAS) score of low back and leg pain, Oswestry Disability Index (ODI), Short-Form 36 Health Survey Scale (SF-36 scale), intervertebral disc height (IDH), sagittal Cobb angle, lumbar lordosis (LL), and the intervertebral fusion were compared between the two groups. Results Compared with MT-TLIF group, UBE-TLIF group had significantly longer operation time but less intraoperative blood loss and shorter length of hospital stay (P<0.05). The Hb levels in both groups decreased at 1 day after operation, but there was no significant difference in the difference before and after operation between the two groups (P>0.05). All patients were followed up, and the follow-up time was (14.7±2.5) months in the UBE-TLIF group and (15.0±3.4) months in the MT-TLIF group, with no significant difference (t=0.406, P=0.686). In both groups, the VAS score of low back pain, VAS score of leg pain, SF-36 scale, and ODI after operation significantly improved when compared with those before operation (P<0.05). There was no significant difference between 1 month after operation and last follow-up (P>0.05). There was no significant difference in the VAS score of low back pain, VAS score of leg pain, and SF-36 scale between the two groups before and after operation (P>0.05). At 1 month after operation, the ODI in the UBE-TLIF group was significantly better than that in the MT-TLIF group (P<0.05). At 1 month after operation, IDH, Cobb angle, and LL in both groups recovered when compared with those before operation (P<0.05), and were maintained until last follow-up (P>0.05). There was no significant difference in the IDH, Cobb angle, and LL between the two groups at each time point (P>0.05). Thirty-three cases (89.2%) in the UBE-TLIF group and 35 cases (87.5%) in the MT-TLIF group achieved fusion, and the difference was not significant (χ2=0.015, P=0.901). In the UBE-TLIF group, 1 case of intraoperative dural tear and 1 case of postoperative epidural hematoma occurred, with an incidence of 5.7%. In the MT-TLIF group, 1 case of intraoperative dural tear, 1 case of postoperative epidural hematoma, and 1 case of superficial infection of the surgical incision occurred, with an incidence of 7.5%. There was no significant difference in the incidence of complications between the two groups (χ2=1.234, P=1.000). Conclusion Compared with MT-TLIF, UBE-TILF can achieve similar interbody fusion in the treatment of lumbar degenerative diseases, and has the advantages of smaller incision, less bleeding, and shorter length of hospital stay.