The goal of this study is to evaluate basic usability and confirm expected safety and effectiveness of SinuSys Dilation System when used to dilate frontal recess and sphenoid sinus ostia in patients with chronic rhinosinusitis.

A multicenter, single arm, prospective study conducted to assess the safety and effectiveness of an osmotically-drive, low-pressure expansion device for dilation of frontal recess and sphenoid sinus ostia in patients with chronic rhinosinusitis (CRS).

Inclusion Criteria:

• Diagnosis of CRS
• Subject in in need of frontal recess and/or sphenoid sinus dilation

Exclusion Criteria:

• Pregnant or breastfeeding females
• Previous treatment site intervention
• Cystic fibrosis, aspirin sensitivity, steroid dependent asthma, sinonasal tumors, allergic fungal sinusitis, ciliary dysfunction, atrophic nasal mucosa, excessive osteogenesis that might preclude dilation