$pathological fracture presence$ $pathological fracture presence$

Table 1 shows the patient characteristics and results of the univariate analysis. Therefore, we considered several risk factors which included the number of mandibular teeth with a poor prognosis at initial evaluation before RT and when fractured, and the proportion of antibiotic administration period in a follow-up duration after RT. We focused on accumulation of infection as an important factor for resulting in pathological fracture. This study retrospectively investigated the risk factors for pathological fracture in patients with mandibular ORN. To control infection of ORN and prevent pathological fractures of the mandible, understanding the occurrence is mandatory. Surgery carries the risk of further dysfunction and esthetic disability, and the stress on patients after severe cancer treatment is immeasurable. The most reliable treatment is resection concomitant with well-vascularized free flap transfer 17. Patients with pathological fractures are required to undergo surgery. In addition, mandibular ORN often results in pathological fractures as it progresses. This further delays the rehabilitation of patients who have completed long-term cancer treatment 15, 16. When ORN develops, patients suffer from severe pain, trismus and deterioration of esthetics such as oral cutaneous fistula. ORN is defined as loss of mucosal coverage and bone exposure lasting 3–6 months 14. It has been recently found that bone exposure, but not ORN, occurs within 2 years after the completion of RT, with an incidence of 6% 12 to 7% 13. The occurrence of ORN has declined with the use of Intensely Modulated Radiation Therapy (IMRT) but still ranges from 4 to 7% as reported in recent large-scale, prospective studies or as reported in a systematic review 6, 7, 8, 9, 10, 11. The National Comprehensive Cancer Network (NCCN) guidelines recommend prophylactic extraction of infected teeth at least 2 weeks prior to RT 5. Several authors reported the significant correlation between tooth extraction after RT and the occurrence of ORN 2, 3, 4. Osteoradionecrosis (ORN) of the jaw is a serious and intractable adverse event that is associated with RT for head and neck cancer. Radiation therapy (RT) plays a central role in the treatment of head and neck cancer, especially in human papillomavirus (HPV)-positive oropharyngeal carcinoma 1. Surgeons should consider extraction of those teeth regardless of before/after RT if necessary for infection control. The patient with a larger number of mandibular teeth with P4 periodontitis may have a risk of not only occurrence of ORN but resulting in pathological fracture by accumulation of infection. Multivariate analyses showed statistically significant associations between pathological fracture and a larger number of mandibular teeth with a poor prognosis when fracture occurred (hazard ratio 3.669). The proportion of antibiotic administration period in a follow-up duration was also significant risk factor ( P = 0.002). Especially, a larger number of mandibular teeth with P4 periodontitis, in other words severe periodontal status, was related to pathological fracture in both timings. We found that pathological fracture was significantly associated with a larger number of mandibular teeth with a poor prognosis at initial evaluation before RT ( P = 0.024) and when fracture occurred ( P = 0.009). The median of duration between RT completion and fracture occurrence was 74.0 months. The rate of occurrence of pathological fractures in patients with mandibular ORN was 25.7%.

$pathological fracture presence$

We investigated various risk factors for pathological fracture in patients with mandibular ORN, including number of mandibular teeth with a poor prognosis each at initial evaluation before radiation therapy (RT) and when fracture occurred, and the proportion of antibiotic administration period in a follow-up duration after RT. Seventy-four patients with mandibular ORN were included in this retrospective study. We aimed to identify the risk factors for pathological fracture in patients with mandibular ORN. Osteoradionecrosis (ORN) often results in pathological fractures through progression.

$pathological fracture presence$

Pathological fracture presence