Data from: Airflow in the human nasal passage and sinuses of chronic rhinosinusitis subjects

Chronic Rhinosinusitis (CRS) is a persistent inflammatory disease of the paranasal sinuses that is characterized by clinical symptoms that include a blocked nasal airway, mucus discharge, facial pain, headaches and anosmia [1, 2]. Functional endoscopic sinus surgery (FESS) is performed on patients who fail to improve following medical therapies such as antibiotics and corticosteroids (both systemic and topical nasal sprays). In sinus surgery, the goals are to open the obstructed sinus openings (ostia), to improve sinus ventilation and to restore mucociliary clearance. After initial surgery, a number of patients may continue to have ongoing symptoms and recalcitrant disease for which a more extensive operation such as the Modified Endoscopic Lothrop procedure (MELP) is performed [3–5]. The MELP procedure differs from standard frontal sinus dissection because both the frontal beak that narrows the frontal ostia, and the adjacent upper part of the nasal septum and frontal intersinus septum are removed, creating a single large common drainage pathway for both frontal sinuses. Current understanding of the relationship between nasal geometry (pre- and post-operative) and sinus ventilation is poor; and despite surgical intervention, efficient topical distribution of therapeutic drugs remains a significant challenge. Simulating nasal airflow in this complex patient group will improve our understanding of how surgical strategies affect post-surgical sinus ventilation, as well as providing new understanding for how drug delivery treatments and devices [6–10] can be designed to target delivery to the sinuses. Nasal passage is connected to sinus air pockets through an opening called ostia. Airflow in the human nasal cavity has been extensively studied using fluid dynamic simulations. We refer the reader to [11] and references there on. A number of studies have simulated airflow in both nasal passage and the sinuses [10, 12–24]. Xiong et al [12] simulated nasal airflow at 21 L/min in a normal healthy subject and found very little flow between the nasal passage and the sinuses. At the frontal sinus ostium they observed a limited flow rate of 0.014mL/s during inspiration and 0.018 mL/s during expiration. Zhu et al. [20] evaluated post-surgical airways after uncinectomy and bilateral inferior turbinate reduction and noticed that the surgery that aimed to affect flow partitioning also increased sinus ventilation in only one respiratory phase. The effects of surgery on altering nasal airflow is a complex realm and are not completely understood. Also, these studies do not sufficiently describe airflow in the sinus. This study describes airflow in the nasal passage and sinuses using fluid dynamic simulations. Specifically, airflow in pre-operative and post-operative CRS subject is investigated. FESS in CRS patients is known to increase nasal airway patency, however although this leads to reduced nasal resistance, the role of surgery in altering exchange of air between the sinus and nasal passages is not clear. Transient airflow is simulated in a healthy normal subject, a pre-operative subject with CRS, the same subject post-operatively after a standard FESS procedure, and a post-operative subject after a Lothrop procedure. Particular focus is given to describing airflow at the openings to the frontal and maxillary sinuses.慢性鼻-鼻窦炎（Chronic Rhinosinusitis, CRS）是一种持续发作的鼻旁鼻窦炎性疾病，临床症状表现为鼻塞、流涕、面痛、头痛及嗅觉丧失[1,2]。对于抗生素、糖皮质激素（包括全身给药与局部鼻用喷雾剂）等药物治疗无效的患者，需实施功能性鼻内镜鼻窦手术（Functional endoscopic sinus surgery, FESS）。鼻窦手术的目标在于开放阻塞的鼻窦口（ostia）、改善鼻窦通气并恢复黏液纤毛清除功能。初次手术后，部分患者仍可出现持续性症状且病情顽固，需接受改良内镜Lothrop手术（Modified Endoscopic Lothrop procedure, MELP）等更为广泛的手术治疗[3–5]。与标准额窦解剖手术不同，改良内镜Lothrop手术需切除狭窄额窦口的额隐窝、相邻的鼻中隔上部及鼻窦间额间隔，为双侧额窦打造单一宽大的共同引流通道。当前学界对鼻腔几何形态（术前与术后状态）与鼻窦通气的关联认知不足；即便实施手术干预，治疗药物的高效局部递送仍是重大挑战。对这类复杂患者群体开展鼻腔气流模拟研究，可加深我们对手术策略如何影响术后鼻窦通气的理解，同时也能为靶向鼻窦的药物递送方案与器械[6–10]的设计提供新的理论支撑。鼻腔通过称为窦口（ostia）的开口与鼻窦气腔相连。人体鼻腔内的气流已通过流体动力学模拟得到广泛研究，相关综述可参见文献[11]及其参考文献。已有多项研究对鼻腔及鼻窦内的气流进行了模拟分析[10,12–24]。Xiong等[12]对一名健康受试者在21L/min流量下的鼻腔气流进行模拟，发现鼻腔与鼻窦之间的流量极小：在额窦口处，吸气时流速仅为0.014mL/s，呼气时为0.018mL/s。Zhu等[20]评估了钩突切除联合双侧下鼻甲缩小术后的气道情况，发现旨在改变气流分配的手术仅在某一呼吸时相提升了鼻窦通气量。手术对鼻腔气流的影响机制复杂，目前尚未完全阐明；且现有研究未能充分描述鼻窦内部的气流特征。本研究通过流体动力学模拟分析了鼻腔及鼻窦内的气流，具体针对慢性鼻-鼻窦炎患者术前与术后的气流展开研究。已知慢性鼻-鼻窦炎患者接受功能性鼻内镜鼻窦手术后可提升鼻腔气道通畅性，尽管这能降低鼻腔阻力，但手术对鼻窦与鼻腔之间气体交换的影响仍不明确。本研究分别对健康受试者、慢性鼻-鼻窦炎术前患者、接受标准功能性鼻内镜鼻窦手术后的同一患者，以及接受Lothrop手术后的患者进行了瞬态气流模拟，并重点关注额窦与上颌窦开口处的气流特征。