New bone formation in unilateral rhinosinusitis

Background: Computed tomography (CT) frequently shows abnormal bone thickening in patients with chronic rhinosinusitis. The sinus bone may be not in a static state, and remodeling occurs in response to chronic inflammation. Methods: Ostiomeatal unit CT scans were reviewed in 29 patients with unilateral rhinosinusitis (URS) undergoing endoscopic sinus surgery. We defined new bone formation (NBF) as a remarkable bone thickening or hyperostosis of the intrinsic sinus walls in comparison with the normal side. Bony CT scores of sinus walls were expressed by the Hounsfield unit (HU) and soft tissue CT scores were measured by the Lund-Mackay system. Results: Almost all of the NBF was located at the maxillary and anterior ethmoid sinuses (83.7%), and it was significantly increased in patients with higher Lund-Mackay scores (p = 0.043). The HU values were significantly different between NBF and non-NBF contralateral sides (p < 0.05). Conclusion: The HU may be helpful to diagnose and quantify the bone remodeling in URS.