[Applied anatomical characteristics of vascularized iliac muscle flap and its clinical application in repairing oral and maxillofacial defects].

Purpose: To investigate the feasibility and safety of the deep circumflex iliac artery (DCIA) derived chimeric flap through the anatomical study of the blood vessels and perforating branches in the ilioinguinal region, and to provide the basis for selecting different DCIA chimeric flap schemes according to the difficulty of surgery, defect conditions and repair needs.

Methods: Six Chinese adult specimens were dissected by retrograde perfusion of red latex into bilateral femoral arteries. At the same time, the length, diameter and main branch position of DCIA vascular pedicle were measured in 12 lower limb CTAs, and compared with the anatomical data. Six patients with oral tumors accompanied by mandibular defects who were treated in the Department of Oral and Maxillofacial Surgery, Affiliated Stomatological Hospital of Nanjing Medical University from July 2020 to November 2021 were repaired and reconstructed with the chimeric iliac myofascial flap. The postoperative appearance and occlusal function of the recipient area were observed. SPSS 19.0 software package was used for data analysis.

Results: A total of 19 DCIA perforators with an external diameter of ≥ 0.5 mm were found in 12 specimens of ilioinguinal region. These perforators were distributed in the 5 cm×3 cm area, inside the ilium and 5cm behind the anterior superior iliac spine. The length of DCIA vascular pedicle was (6.73±1.06) cm. The measured value of the external diameter of the starting position of the vascular pedicle was (2.55±0.29) mm. The outer diameter of DCIA skin perforator penetrating deep fascia was (1.12±0.14) mm. In the CTA analysis of 12 lower limbs, it was found that the length of DCIA vascular pedicle was (6.98±0.62) cm. The measured diameter at the original position of vascular pedicle was (2.35±0.20) mm. Six cases of mandibular defects were repaired with iliac internal oblique fascia mosaic flap. Six cases of lliac flap survived successfully after operation. Follow up for 6 to 24 months (average 12 months) showed that the mandibular shape and function recovered well, the intraoral myofascial flap became mucosal, and the implanted iliac bone showed no significant volume change on CT after operation. Walking and weight bearing in donor area were basically normal, and no abdominal hernia occurred.

Conclusions: DCIA and its main branches have a relatively constant course and distribution in the ilioinguinal region. According to the conditions of different defect areas, different tissue types of chimeric flaps based on DCIA can be prepared to meet the repair requirements. The donor site complications can be controlled, and it is an ideal choice to repair mandibular defects.