The Clinical Retrospective Study And Histopathological Research For Osteoradionecrosis Of The Jaws

Objective: One purpose of this study is to discuss the diagnoses, treatment and prevision of ORNJ through a retrospective study which composed 262 cases treated in our hospital over the past ten years. Second purpose is to propose a new classification and stage for ORN of the mandible through imaging and clinical examination. Third purpose is to demonstrate the histopathological features and possible etiology mechanism of ORNJ through histopathological study. Materials and methods:1. Medical records of 262 ORNJ patients, who treated in our hospital between January 2003 and January 2015, were retrospectively reviewed.2. “B” represents the bone destruction measured by CT scans, and “S” represents the soft tissue defects through clinical examination, proposed a classification and stage for ORN of the mandible.3. HE staining, Masson staining and immunohistochemical methods are used for ORNJ histopathological research.4. For statistical analysis, T-test, analysis of variance, chi-square test, non-parametric test and Fisher's exact test are used. Statistical significance is set at P <0.05. Results:1. In 262 recruited patients, 222(84.73%) patents ORN located in mandible(unilateral: 200 cases, bilateral: 22 cases). The average time of necrosis is 2 years(1 month-38 years) and the average total radiation dosage is 80.1Gy(35Gy-150Gy). In 222 patients, 203(91.44%) accepted surgical treatment, and 27(13.30%) experienced mild surgical procedures such as sequestrectomy or debridement, and 176(86.70%) underwent radical necrosis bone resection. In radical resection groups, 53(39.85%) received simultaneous vascularized bone flap transfer and fibula flap 49(92.45%) cases. Another, 77(57.89%) patients received simultaneous vascularized soft tissue flap transfer and PMMF 62(80.52%) cases. After operation, 59(29.06%) patients generated postoperative complications due to vascular crisis, hematoma, wound dehiscence or fistula. Primary tumor treatment methods such as radiotherapy, surgery and chemotherapy are associated with ORNJ. Reduce or control some of these risk factors are the primary means of prevention ORNJ. In discharge, 151(74.38%) patients wound healed one stage and 52(25.62%) patients local wound need dressing due to the postoperative complications.2. Twenty-four(9.16%) patients ORN located in maxilla. The average time is 5.9 years(3 months-16 years) and the average radiation dosage is 80Gy(60Gy-184Gy). In all 24 patients, 17(70.83%) received surgical treatment(sequestrectomy or debridement 6 cases, and radical resection 11 cases). In radical resection groups, 7 patients received simultaneous vascularized tissue flap transfer(ALT 2 cases, PMMF 1cases, latissimus dorsi flap 1 cases, forearm 1 case, palatal flap 1case, nasolabial flap 1 case). In discharge, five patients wound healed one stage, and 12 local inflammations were controlled.3. Sixteen(6.11%) patients ORN involved in the upper and lower jaws. The average time of ORN occurred is 5.15 years(4 months-17 years) and the average total radiation dosage is 103.63Gy(60.12Gy-158Gy). For ORN of maxilla, local necrosis tissue debridement was the major treatment methods. For ORN of the mandible, six received radical resection and simultaneous vascularized tissue flap transfer(fibula flap 2case, vascularized iliac & forearm flap 1cases, PMMF 3 cases). Most of patient's local inflammation controlled well and limited mouth opening also improved when they were discharge.4. According to bone(B) necrosis measurement and soft tissue(S) defects investigations, we divided the ORN of the mandible into 10 clinical categories(B0S0, B1S0, B1S1, B1S2, B2S0, B2S1, B2S2, B3S0, B3S1, B3S2) and four phase(Stage 0- III).5. The common ORNJ histopathological findings were trabecular bone resorption like jagged and with empty osteocytic lacunae, empty Haversian systems. Masson and HE staining all showed the characteristic fibrotic tissue existed in the marrow of ORNJ. Immunohistochemistry study also showed high expression about fibrosis-related factors TGF-?1 and myofibroblast characteristic marker proteins ?-SMA in the marrow of ORNJ. Conclusion:1. Mandible is the most predilection sites for ORN than maxilla and upper and lower jaws. Primary tumor and its treatment methods play an important role in process of ORNJ. Radical resection the necrosis tissues followed by well-vascularized tissue flap reconstruction is a reliable and effective procedure in the management of patients who unresolved with conservative non-operative treatment. Fibula flap is our first choice for postoperative bone defects reconstruction. PMMF is a most common used soft flap to provide an expedient means for primary wound healing.2. It is a convenient and simple method to management of ORN of the mandible using BS classification.3. ORNJ is a radiotherapy-induced and non-infectious necrosis. Local trauma and infection factors only play a role in fueling. The bone marrow fibrosis and ORNJ probably have a closely relationship.