Although physician-modified fenestrated and branched endografts (PMEGs) were proposed as an alternative to thoracoabdominal aortic aneurysms (TAAAs) repair in 2012, PMEG use is still limited by the lack of long-term data in large series. We seek to compare the midterm outcomes of PMEGs in patients with postdissection (PD) and degenerative (DG) TAAAs. Data were analyzed for 126 patients (age 68±13years; 101 men [80.2%]) with TAAAs treated by PMEGs from 2017 to 2020, including 72 PD-TAAAs and 54 DG-TAAAs. Early and late outcomes were compared between patients with PD-TAAAs and DG-TAAAs, including survival, branch instability, and freedom from endoleak and reintervention. Hypertension and coronary artery disease were present in 109 (86.5%) and 12 (9.5%) patients. PD-TAAA patients were younger (63±10 vs 75±12years; P<.001), and more likely to have diabetes (26.4 vs 11.1; P=.03), history of previous aortic repair (76.4% vs 22.2%; P<.001), and smaller aneurysm size (52 vs 65mm; P<.001). TAAAs were extent I in 16 (12.7%), II in 63 (50%), III in 14 (11.1%), and IV in 33 (26.2%). Procedural success was 98.6% (71 out of 72) and 96.3% (52 out of 54) for PD-TAAAs and DG-TAAAs (P=.4). The DG-TAAAs group sustained more nonaortic complications than PD-TAAAs (23.7% vs 12.5%; P=.03) in adjusted analysis. Operative mortality was 3.2% (4 out of 126), which didn't differ between the groups (1.4% vs 5.6%; P=.19). The mean follow-up was 3.01 ± 0.96years. There were 2 (1.6%) late deaths (from retrograde type A dissection and gastrointestinal bleeding [n=1 each]), 16 (13.1%) endoleaks, and 12 (9.8%) instances of branch vessel instability. Reintervention was performed in 15 (12.3%) patients. At 3years, survival, freedom from any branch instability, and freedom from endoleak and reintervention were 97.2%, 97.3%, 86.9%, and 85.8% in the PD-TAAAs group, respectively, which did not differ significantly from DG-TAAAs patients (92.6%, 97.4%, 90.2%, and 92.3% all P values > .05). Despite the difference in age, diabetes, prior history of aortic repair, and aneurysm size preoperatively, PMEGs achieved similar early and midterm outcomes in PD-TAAAs and DG-TAAAs. Patients with DG-TAAAs were more prone to early nonaortic complications, which represents an aspect for improvement to optimize outcomes and warrants further study.