A retrospective analysis of 329 patients at one single institution between January 2014 and December 2019 who underwent free fibula flap reconstruction was conducted. A variety of clinicopathological postoperative parameters were identified and assessed.

The study was conducted as a monocentric, retrospective study. Patients who underwent a mandibular reconstruction with a free fibula flap due to head and neck cancer through January 2014 to December 2019 at one single institution in Taiwan were identified. All charts including surgical records, progress notes, nursing records, clinic notes, imaging study after surgery were reviewed. Data extraction was performed for the following variables: Patient demographics, primary diagnosis, cancer location and staging, treatment prior to index surgery, postoperative hemoglobin and albumin, operating time, flap type, mandibular defect length, type of the defect according to Jewer's classification, ischemia time, number of fibula segments, plate type, re-exploration, time of hospitalization, postoperative radiotherapy and/or chemotherapy, ORN cases, identification time of ORN and management for ORN. The patients were then organized into two groups: ORN and non-ORN. This research was approved by the Institutional Review Board of our hospital (No. 201800172B0), which was available until 2022/02/28. The investigators completed data analysis before 2022/02/28 and then initiated manuscript preparing.

Inclusion Criteria:

• Patients who underwent a mandibular reconstruction with a free fibula flap due to head and neck cancer through January 2014 to December 2019.

Exclusion Criteria:

• Cases with incomplete medical records.
• Patients who did not attend at least 6 months of follow ups.

Between January 2014 and December 2019, 580 patients received free fibula flap mandibular reconstruction, with 374 of them attributed to head and neck cancer reconstruction. Cases with incomplete medical records were excluded (n = 9). Additionally, patients who did not attend at least 6 months of follow-up were also excluded (n = 36). Finally, 329 patients including 309 males and 20 females met the inclusion criteria of this study.