Chronic rhinosinusitis (CRS) is one of the most common medical conditions in the US,
affecting an estimated 13% of adults, or some 30 million people. It accounts for 12.5
million physician office visits each year and an annual health care expenditure of $5.8
billion (National Health Interview Survey 2009, CDC). Major symptoms include nasal
obstruction, facial pain/pressure, nasal discharge, purulence in the nasal cavity, and
loss of smell. These symptoms significantly impact patient quality of life, even compared
to chronic debilitating diseases such as diabetes and congestive heart failure.
Topical therapies play an integral role in the management of CRS, and high-volume
irrigation delivery (e.g., neti pot, squeeze bottles) is more effective for achieving
distribution to the sinuses than other topical delivery methods such as nasal sprays,
nebulizers, or atomizers. Saline irrigations have been recommended in a number of
clinical scenarios, including initial management of CRS and postoperative care.
High-volume irrigations have also shown benefits for medication delivery, such as with
mupirocin and corticosteroids. However, due to the intricate and variable anatomy of the
human nasal airway, the efficacy of topical irrigations is inconsistent and difficult to
predict. Previous studies from our group and others have shown that nasal irrigant may
not reliably penetrate all sinuses, and the effectiveness varies depending on specific
sinuses, head positions, injection angle, pressure, flow rates, and other factors. We
currently do not have a clear understanding of the optimal delivery technique(s). In
efforts to improve these outcomes, the efficacy of topical irrigation delivery to target
sinuses is an area of active research. Yet, investigations have been limited by
labor-intensive methodologies, such as cadaver studies or using colored dyes followed by
endoscopy to visualize where the irrigation might have reached. Other studies have used
irrigations with iodinated contrast followed by computed tomography (CT) scans to
determine which sinuses collect contrast material. Similarly, technetium 99m sulfur
colloid and fluorescein have also been used as tracers to visualize the distribution of
sinus irrigations. These labor-intensive techniques are difficult to apply to a large
sample size. They increase patient risk and commonly capture only where the irrigation
fluid has been at the end of irrigation, but not the details of irrigation flow paths
that would allow us to understand why the irrigation outcomes vary.
From both patients' and clinicians' perspectives, the lack of clear prediction of
patient-specific irrigation outcomes can be frustrating, as clinicians prescribe a
rigorous daily irrigation routine but have no assurance that what patients are doing is
effective. When symptoms fail to improve after courses of irrigation, it is difficult to
determine whether the added medication is not working, or the irrigation does not reach
clinically relevant targets deep within the sinuses. Many patients and surgeons thus opt
for systemic medication or surgery, which increases risk of overmedication, growth of
resistant organisms, systemic side effects, and serious risk from surgery.
The purpose of this study was to propose a novel idea: applying three-dimensional
(3D)-printing technology based on individual patients' computed tomography (CT) scans to
determine an optimal personalized nasal irrigation strategy (head positions, angle of
injection, flow rates, etc.).
