151751-Najiba-Chargi

96 CHAPTER 6 MATERIAL AND METHODS ETHICAL APPROVAL The design of this study was approved by the Medical Ethical Research Committee of the University Medical Center Utrecht (approval ID 17-365/C). All procedures in this study were in accordance with the ethical standards of the institutional and/or national research commit- tee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. PATIENTS AND STUDY DESIGN A retrospective study was performed of all consecutive patients who had undergone recon- struction of segmental mandibular defects with free fibula flaps between 2002 and 2018 at the Department of Oral and Maxillofacial Surgery and the Department of Head and Neck Surgical Oncology, of the University Medical Center, Utrecht, the Netherlands. A previously published article by our group has studied early and late surgical complications in a part of these pa- tients. 20 Patients were included if they had primary tumor resections without prior treatment and recent (less than 1 month before surgery) imaging (CT or MRI scans) of the head and neck. Clinical and demographic data were collected from themedical records. Data collected includ - ed age at reconstruction, sex, smoking history, diagnosis, localization of defect, comorbidity as expressed by the Adult Comorbidity Evaluation-27 (ACE-27) score, history of radiation therapy, flap ischemia time, occurrence of complications and survival data. All surgical procedures were performed by head and neck surgeons who are experienced in microvascular surgery. Details of surgical procedures are described in a previously published article by the same group of surgeons. 20 All patients were discussed in a tumor board meeting and underwent pre-opera- tive angiography and Doppler examination of the lower leg to assure adequate blood supply to the foot and skin paddle. FFF complications were defined as all complications concerning the flap, such as partial skin paddle necrosis, dehiscence, venous congestion or vascular thrombosis and failure. All non- flap related postoperative complications were scored according to the Clavien-Dindo classi- fication of surgical complications. 22 Patients with multiple complications were categorized according to their highest grade of complication. Complications with a Clavien-Dindo grade III-IV were graded as severe complications. Survival data was retrieved frompatients’ medical record. Patients were regularly seen in the first 5 years of follow-up after reconstruction. We defined overall survival (OS) as the time between the date of diagnosis and date of death or last follow-up, whichever occurred first. We defined disease-free survival (DFS) as the time be - tween the date of diagnosis and date of recurrence or last follow-up, whichever occurred first.