A study on the morphology of iliac crest based on the objectives of jaw bone defect reconstruction.

OBJECTIVES: to understand the morphological characteristics of iliac crest and provide advice and assistance for jaw bone reconstruction with iliac bone flap by evaluating the thickness and curvature of iliac crest. MATERIALS AND METHODS: 100 patients who had taken Spiral CT of the Abdominal region before surgeries between 2020 and 2022 were included in this study. 3D reconstruction images of the iliac bones were created. 5 vertical planes perpendicular to the iliac crest were made every 2 cm along the centerline of the iliac crest (VP2 ~ VP10). On these vertical planes, 4 perpendicular lines were made every 1 cm along the long axis of the iliac crest (D1 ~ D4). The thicknesses at these sites, horizontal angle (HA) of iliac crest and the distance between inflection point and the central point of anterior superior iliac spine (DIA) were measured. RESULTS: The thickness of iliac bone decreased significantly from D1 ~ D4 on VP6 ~ VP10 and from VP2 ~ VP10 on D3 and D4 level (P<0.05). HA of iliac crests was 149.13 ± 6.92°, and DIA was 7.36 ± 1.01 cm. Iliac bone thickness, HA and DIA had very weak or weak correlation with patient's age, height and weight. CONCLUSIONS: The average thicknesses of iliac crest were decreased approximately from front to back, from top to bottom. The thickness and curvature of the iliac crest were difficult to predict by age, height and weight. CLINICAL RELEVANCE: Virtual surgical planning is recommended before jaw bone reconstruction surgery with iliac bone flap, and iliac crest process towards alveolar process might be a better choice.

Changes of the facial soft tissue after mandibular reconstruction using vascularized iliac flap.

OBJECTIVES: To reveal the change patterns of the facial soft tissue after applying mandibular reconstruction. MATERIALS AND METHODS: 16 Patients with mandibular benign tumor were recruited in this retrospective study. For all patients, segmental mandibular osteotomy and concurrent reconstruction using vascularized iliac flap were conducted. The soft tissue thickness of patients' lower face was measured with CT scans before surgery, 1 week, 6 months and 1 year after surgery. The time-dependent changes of tissue thickness were analyzed. RESULTS: The most significant tissue swelling was 28.86%, at 1 week after the surgery. The average increase of tissue thickness was 4.78 ± 5.30 mm across patient. After 1 year of the surgery, tissue thickness decreased to the level before operation or the level of the healthy side. The thickness of the low-density tissue fluctuated mildly, while the thickness of the high-density tissue fluctuated significantly. The disuse atrophy of the masseter occurred 1 week after the surgery, and was reversed after 1 year. The removal of the submandibular gland caused depression in submandibular area, which intensified over time. CONCLUSION: Across patients, soft tissue thickness in the lower face after mandibular osteotomy and reconstruction increased significantly 1 week after the surgery, and decreased over time. After 1 year, tissue thickness went back to the pre-surgery level, where matched up with the healthy side. CLINICAL RELEVANCE: We documented the change patterns of the facial soft tissue after mandibular reconstruction. These results can help improve the planning of virtual surgeries and the timing for aesthetic assessment. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: ChiCTR2100054103.

Study on biomass based nanofibers preparation by electrospinning.

The electrospinnability of lignin was improved by blending in a solution of polyacrylonitrile (PAN) resulting in the reduction of the nanofiber cost. The compositions containing low concentration of the lignin shows good spinnability. The influences of main process parameters, such as flow rate, voltage and concentration on the nanofibers morphology were studied by scanning electron microscope (SEM). The results indicated that by changing parameters, nanofibers with good morphology were obtained. According to the study, when other parameters were kept unchanged, the parameters to prepare ideal nanofibers are as follows: flow rate is 0.04 mm/h; the voltage is 25 kV and the lignin amount is 2 wt.%. The results of this work showed that this novel method is a quite promising technique for preparation of biomass based carbon nanofiber precursors.

Retrospective study of the deep circumflex iliac artery flap and the vascularized fibula free flap for maxillary defect repair.

OBJECTIVES: The deep circumflex iliac artery flap (DCIA) and vascularized fibular free flap (FFF) are mainstay flaps for maxillary defect reconstruction. This study compared the functional outcomes and success rates of these flaps to provide midface reconstruction strategies. MATERIALS AND METHODS: Maxillary defects reconstructed with DCIA or FFF at the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology between May 2016 and May 2023 were retrospectively analyzed. The length, width, and height of the grafted bone segments; intermaxillary distance; buttress reconstruction rate (BRR); dental arch reconstruction rate (DAR); success rate; and dental implantation rate were compared. RESULTS: The DCIA and FFF groups had 33 and 27 patients, respectively. Success rate in the DCIA group was 93.94 % and 100 % in the FFF group. The DCIA length was less than that of FFF; however, the width and height were significantly larger. 87.10 % of cases in the DCIA group were classified as Brown class b and c, 51.85 % of cases in the FFF group were classified as Brown class d. The average BRR in the DCIA group was 69.89 % ± 16.05 %, which was significantly higher than that in the FFF group. A total of 38.7 % and 11.1 % patients in the DCIA and FFF groups, respectively, had completed implantation. CONCLUSION: DCIA has a greater width and height, and is more suitable for repairing Brown class b and c defects, providing sufficient bone for implantation, while the FFF is longer and more suitable for Brown class d defect reconstruction.