BackgroundIn the field of head and neck microvascular reconstruction, no previous study has compared arterial and venous grafting as methods of anterolateral thigh (ALT) pedicle lengthening. Therefore, we conducted this comparative study to compare the outcomes between the two pedicle lengthening techniques.MethodsWe performed comparative effectiveness research by conducting a retrospective chart review from January 2012 to December 2021 to identify patients who underwent head and neck reconstruction with non‐descending branch ALT perforator flaps using either the in situ pedicle lengthening (ISPL) technique or the vein graft (VG) technique. A total of 26 patients were analyzed, including 14 who underwent ISPL, and 12 who underwent VG. The collected data, including patient demographics, surgical indications, history of prior free flap, prior neck dissection, radiation therapy, chemotherapy, graft length, and flap outcomes, were analyzed. The flap outcomes were categorized as total flap loss, partial flap loss, flap compromise that required operating room visits, or minor issues, including infection or dehiscence. The flap characteristics and postoperative outcomes were compared between the two groups.ResultsThe VG group had two flap losses, whereas the ISPL group had none. Although the failure rate was higher in the VG group than that in the ISPL group, the difference was not statistically significant (0% vs. 16.7%, p = 0.203). Additionally, there were no significant differences in flap take‐back (14.3% vs. 16.7%, p = 1) and minor complications between the two groups (35.7% vs. 33.3%, p = 1).ConclusionsIf pedicle lengthening with vessel graft is inevitable in head and neck reconstruction, arterial graft may provide a reliable outcome and may be considered an effective alternative when compared to vein grafts.