Radiographic osteoradionecrosis of the jaw with intact mucosa: Proposal of clinical guidelines for early identification of this condition

Osteoradionecrosis (ORN) remains an unintended debilitating complication of radiation therapy despite the advent of intensity-modulated radiation therapy (IMRT) which aims to deliver doses of radiation to the tumor site while minimizing doses to healthy tissues [[1], [2], [3], [4]. The etiopathogenesis of ORN has been attributed to the avascular effect of radiation to the bone resulting in hypoxia, hypovascularity, and hypocellularity [5], [6]. Radiation-induced fibrosis has also been implicated in the pathophysiology of ORN [7. Recent studies have placed reported incidences of ORN at 1–30% [2], [8], [9], [10], [11]. ORN of the jaw was defined as an area of exposed necrotic bone greater than 1 cm in an area of previous irradiation that failed to heal after 6 months [5]. This definition of ORN has been used for years and still remains the most widely used clinical criterion for the diagnosis of ORN though it fails to incorporate cases with radiologic evidence of necrosis with intact mucosa [5], [12], [13], [14], [15]. Although a report by Van Merkesteyn et al. described a case of ORN of the jaw with intact mucosa [16], subsequently only two series have likewise reported this condition. In 2000, Store and Boysen reported 17 patients with radiographic osteoradionecrosis of the jaw (rORN) with intact mucosa at initial diagnosis as did He et al. in a recent article where they described 16 patients presenting with rORN with intact mucosa [17], [18]Thus, it appears that rORN with intact mucosa is underdiagnosed. The objectives of this article are to: 1. Describe new cases of rORN with intact mucosa. 2. Correlate the dosimetric analyses of the involved area with the radiographic presentation and to determine the best predictor of rORN with intact mucosa. 3. Propose modification of Store and Boysen’s staging system of ORN. 4. Propose clinical guidelines for early identification of rORN with intact mucosa.