151751-Najiba-Chargi

160 CHAPTER 9 PATIENTS AND METHODS This study is a retrospective cohort study. The design of this study was approved by the Med - ical Ethical Research Committee of the University Medical Center Utrecht (ID 17 ‐ 365/C). The research was conducted in accordance with the Declaration of Helsinki. PATIENT AND STUDY DESIGN All patients who had undergone TL between January 2008 and May 2017 at the University Medical Center Utrecht, Utrecht, the Netherlands, were considered for inclusion. Patients were discussed in the local tumor board meeting, and all patients who were included under- went TL with or without (partial) pharyngectomy and with or without additional lymph node dissection; either as primary treatment, as salvage treatment for new or residual cancerous tissue after prior (chemo)radiotherapy treatment, or as functional treatment for a dysfunc - tional larynx after prior (chemo)radiotherapy, where no active cancerous tissue was found. Five dedicated head and neck surgical oncologists performed all TL. Exclusion criteria for this analysis included insufficient quality CT imaging as determined by an experienced radiologist or the absence of CT imaging (e.g., only MRI imaging performed). Patients’ demographic, staging, treatment, and outcome data were collected using electronic patient records. Operating records were checked for details of the surgery, neck dissection, and primary pharyngeal closure or flap reconstruction of the pharynx. The occurrence of PCF was defined as a clinical fistula requiring any formof conservative or surgical treatment. In pa - tients who had surgery for a dysfunctional larynx, the tumor site for which the patient received prior treatment was documented. Follow-up data were retrieved up until August 31, 2017. The presence of sarcopenia was assessed on preoperative CT imaging using a previously specified protocol. In brief, the cross-sectional skeletal muscle area at the level of C3 was measured on a single transversal CT slice at the level of the third cervical vertebra (C3).8, 12 The cross-sectional muscle area was normalized for height to calculate the skeletal muscle index. A skeletal muscle index of below 43.2cm 2 /m 2 was deemed to be sarcopenia. 20 IMAGE ACQUISITION All CT imaging was routinely performed at our hospital. Patients underwent contrast-en - hanced CT scanning of the head and neck area on a Philips scanner with 64 detector rows or more (Philips Healthcare, Best, The Netherlands) at our institution. All routine diagnostic CT protocols include thin slices (<1-mm) and reconstruction at 3- 5mm. IMAGE EVALUATION Images were typically analyzed in multiple directions by one reader (P.A.d.J), a radiologist with >10 years of experience in CT evaluation and a specific research interest in arterial calci -