A novel alloplastic grid reconstruction plate for the mandible - Retrospective comparative clinical analysis of failure rates and specific complications.

PURPOSE: This study aimed to investigate the effect of three different osteosynthesis plate systems on failure rates and complications after continuity-interrupting mandibular resections with alloplastic reconstructions. MATERIALS AND METHODS: Records of respective patients from 2010 to 2020 were analyzed retrospectively. The analyses included the osteosynthesis plate type (2.4 MANDIBULAR (RP1: MANDIBULAR [Medicon®, Tuttlingen, Germany]; RP2: Modus® Reco 2.5 [Medartis®, Basel, Switzerland]; and RP3: Modus 2 Mandible [Medartis®, Basel, Switzerland]), extent & location of the defect, age, sex, radiotherapy, and nicotine abuse. In case of failure, timepoint, and the problem, namely oral/extraoral dehiscence, screw loosening, and plate fractures that led to removal, were analyzed. Complications were classified according to Clavien-Dindo system. RESULTS: A total of 136 patients were included. The mean follow-up time was 18 ± 26 months. Survival rates after 1, 2, and 5 years were 69.9%, 66.9%, and 64.7%, respectively. Although survival was not significantly associated with the reconstruction system, the most frequent complications were seen in cases of RP1 & RP2 when compared to RP3 (p = 0.033). In brief, dehiscences were seen significantly less often in cases of RP3 (12.5%) when compared to RP1 (44.7%) and RP2 (26.9%; p = 0.024). Fractures of the osteosynthesis systems occurred in 3 of 4 cases (75%) with RP1, in 1 of 4 cases (25%) using RP2, and in no single case using the RP3 system (p = 0.03). Most of the observed complications occurred up to 12 months postoperatively. A total plate survival rate of 64.7% and a total plate complication rate of 47.8% were seen. CONCLUSION: In conclusion, it seems that RP3 should be preferred over RP1 and RP2 regarding failure rates and complications.

Minimally Invasive Navigation-Guided Quad Zygomatic Implant Placement: A Comparative In Vitro Study.

Purpose: Zygomatic implants (ZIs) have been considered a reliable alternative treatment for patients with maxillary atrophy and/or maxillary defects. The use of a navigation system for assisting ZI placement could be a reliable approach for enhancing accuracy and safety. The purpose of this in vitro study was to evaluate the accuracy of a new dynamic surgical navigation system with its minimally invasive registration guide for quad zygomatic implant placement in comparison with a gold standard navigation approach. Materials and Methods: A total of 40 zygomatic implants were placed in 10 3D-printed models based on the CBCT scans of edentulous patients. For registration, a surgical registration guide with a quick response plate was used for the test group, and five hemispheric cavities as registered miniscrews in the intraoral area were used for the control group. In each model, a split-mouth approach was employed (two ZIs in bilateral zygomata) to test both systems. After ZI placement, a CBCT scan was performed and merged with pre-interventional planning. The deviations between planned and placed implants were calculated as offset basis, offset apical, and angular deviation and compared between the systems. Results: The offset basis, offset apical, and angular deviation were 1.43 ± 0.55 mm, 1.81 ± 0.68 mm, and 2.32 ± 1.59 degrees in the test group, respectively. For the control group, values of 1.48 ± 0.57 mm, 1.76 ± 0.62 mm, and 2.57 ± 1.51 degrees were measured without significant differences between groups (all P < .05). The accuracy of ZI positions (anterior and posterior) were measured without significant differences between groups. Conclusion: Two navigation systems with different registration techniques seem to achieve comparable acceptable accuracy for dynamic navigation of zygomatic implant placement. With the test group system, additional pre-interventional radiologic imaging and invasive fiducial marker insertion could be avoided.

Identification of cutaneous perforators for microvascular surgery using hyperspectral technique - A feasibility study on the antero-lateral thigh.

Aim of the study was to compare perforator vessel location using color-coded Doppler ultrasound and hyperspectral imaging in the area of the antero-lateral thigh. In a cross-sectional case-control study, the bilateral antero-lateral thigh region was examined for perforator vessel location via color-coded Doppler ultrasound (control) and hyperspectral imaging (test). For hyperspectral imaging, all measurements were conducted without cooling (T0) and after 1 (T1), 2 (T2) and 3 min (T3) of cooling. Additionally, in the reperfusion period after cooling, hyperspectral imaging was conducted at 1, 2 and 3 min (T4/T5/T6). Results from color-coded Doppler ultrasound and hyperspectral imaging were matched at all time points (T0-T6). In total, 71/73 perforator vessel locations could be matched (sensitivity: 97%). Matching of color-coded Doppler ultrasound and hyperspectral imaging was significantly influenced by the cooling protocol and the highest matching values were seen at T3 (3 min cooling; 60 perforator vessels) and T4 (3 min cooling & 1 min reperfusion; 62 perforator vessels) without significant differences (sensitivity 98%; p = 0.9). There were significant differences between T4 and T0, T1 (both p < 0.001), T5 (p = 0.045) and T6 (p = 0.012). For clinical proof of concept, a patient case using a free antero-lateral thigh flap for reconstruction of a facial defect after perforator vessel identification via color-coded Doppler ultrasound and hyperspectral imaging (3 min cooling & 1 min reperfusion) was carried out successfully. In conclusion, hyperspectral imaging potentially offers an additional opportunity for non-invasive, user-independent perforator-site assessment if prior cooling of the site is conducted.