[Current developments in primary and secondary surgical treatment of midface and periorbital trauma]. / Aktuelle Entwicklungen in der chirurgischen Primär- und Sekundärversorgung von Mittelgesichts- und periorbitalen Traumata.

Fractures of the periorbita and the midface are among the most common bony facial injuries. Aesthetic and functional reconstruction is a challenge in clinical routine. This article illustrates recent developments in the primary and secondary surgical treatment of midface and periorbital trauma. Resorbable patches and films increase the anatomic reconstructive capacity and enable treatment of extensive orbital fractures. Orbital fractures with involvement of supporting key structures are advantageously reconstructed using patient-specific implants (PSI), which are fabricated by computer-assisted manufacturing techniques and positioned by intraoperative navigation. If late complications such as bulbar malposition and enophthalmos have occurred after the initial procedure, they can be addressed by overcorrective restoration of orbital volume. The use of PSI for initial fracture restoration of the midface is not yet established but may be useful in re-osteotomies of misconsolidated fragments. Extensive midface defects with significant soft tissue involvement can be reconstructed using microvascular grafts. Consecutive reconstructive procedures may include orthognathic surgery and local flap reconstruction. In summary, the integration and advancement of computer-assisted techniques now offers individualized reconstruction procedures, which may be a viable alternative to conventional implants and compression miniplates. Future developments may focus on the search for innovative biomaterials, which can be integrated into computer-aided design and manufacturing processes.

Accuracy and clinical outcomes of mandibular reconstruction with a virtually planned deep circumflex iliac artery flap with stock temporomandibular joint prosthesis.

The repair of hemimandibulectomy defects involving the temporomandibular joint (TMJ) is challenging. This study compared the functional outcomes and reconstruction accuracy using a deep circumflex iliac artery (DCIA) flap with and without a virtually planned stock TMJ prosthesis (TMJP) after hemimandibulectomy. Ten patients were assessed: five with a TMJP (TMJP group) and five without (control group). A three-dimensional comparison revealed a mean deviation of 0.11 ± 0.04 mm between the planned and actual DCIA flap with TMJP. The planned and actual TMJP positions differed by 0.56 ± 0.57 mm in height, 0.33 ± 0.24 mm ventrally/dorsally, and 1.18 ± 0.42 mm medially/laterally. Mouth opening, laterotrusion, and midline deviation were significantly greater in the control group than in the TMJP group (P = 0.024, P = 0.008, P = 0.024). The deviation in ventral to dorsal translation for the DCIA flap was slightly higher than reported values in the literature, while height deviation was comparable. Lower deviations in the literature were due to the DCIA flap being used where both TMJs were intact. The in-house virtually planned DCIA flap with stock TMJP yielded results comparable to more expensive patient-specific prostheses.

Defining biomechanical principles in pre-surgical infant orthopedics in a real cleft finite element model.

Presurgical infant orthopedics (PSIO) is the first step in the treatment of cleft lip and palate (CLP) and is designed to approximate the cleft segments as effectively as possible before surgical reconstruction of the lip and palate. The biomechanical efficacy of different PSIO approaches in transferring molding forces to the CLP is unknown. This study aimed to define the biomechanical principles of competing PSIO techniques in a real cleft finite element (FE) model. Active intraoral (Latham), passive alveolar molding (PAM), and extraoral (DynaCleft) molding forces were virtually applied to a real cleft FE model. In the cleft region, PAM (P < 0.001) and Latham (P < 0.05) exerted significantly less stress than DynaCleft. Intraoral molding forces acted primarily at the site of the force initiation without being accompanied by high loads in the midface. PAM showed a tendency toward a better flow behavior of the molding forces than Latham. Extraoral molding transferred high stresses to the cleft, alveolar ridge, and midface. Intraoral passive molding was ultimately characterized by the highest biomechanical efficacy and showed the most favorable load distribution of all of the PSIO approaches considered in this study. Future research is needed to validate the findings against clinical data.

A cadaveric study of induced isolated orbital floor fractures and implications for surgical decision-making: comparison of two preoperative imaging modalities.

Computed tomography (CT) is the gold standard for the diagnosis of isolated orbital floor fractures, while cone beam computed tomography (CBCT) is an alternative. The aim of this study was to compare the diagnostic accuracy of CT and CBCT for isolated orbital floor fractures. Forty-eight isolated orbital floor fractures were systematically induced in cadaver orbits. CBCT and CT scans of each cadaver head were performed and the image data imported into ProPlan CMF for analysis. The orbital floor area (OFA), orbital defect area (ODA), and peri-orbital tissue herniation were evaluated. Surgical decision-making differed significantly according to the imaging modality (P = 0.031). The odds of decision discrepancy between CBCT and CT were higher with increasing ODA/OFA ratios, when adjusted for peri-orbital tissue herniation and fracture localization (P = 0.026). An ODA/OFA ratio cut-off value of >36.25% had a sensitivity of 100% and specificity of 71% (area under the curve 0.83, P = 0.011) for predicting discrepancies between CBCT and CT in surgical decision-making. In this cadaveric study, CT and CBCT were diagnostically equivalent for isolated orbital floor fractures with an ODA/OFA ratio ≤36.25%. However, fractures exceeding this threshold may be better evaluated by CT to avoid discrepancies in surgical decision-making.

Perfusion of microvascular free flaps in head and neck reconstruction after prior neck dissection and irradiation.

Microvascular free flaps are frequently used for head and neck reconstruction after prior neck dissection (ND) and neck irradiation (RTX). The aim of this study was to investigate the influence of ND and RTX on flap perfusion as a critical factor for flap success. Overall, 392 patients reconstructed with a microvascular fasciocutaneous flap (FF) or perforator flap (PF) in the head and neck region between 2011 and 2020 were analysed retrospectively. Flap perfusion measured intraoperatively and postoperatively with the O2C tissue oxygen analysis system was compared between patients who had received neither ND nor RTX (controls), patients who had received ND but no RTX (ND group), and patients who had received both ND and RTX (ND+RTX group). Intraoperative and postoperative flap blood flow was decreased in FFs in ND group patients compared to controls (median 66.3 AU vs 86.0 AU, P = 0.023; median 73.5 AU vs 93.8 AU, P = 0.045, respectively). In the multivariable analysis, these differences showed a tendency to persist (P = 0.052 and P = 0.056). Flap success rates were similar in control patients, ND patients, and ND+RTX patients (98.7%, 94.0%, and 97.6%, respectively). Flap perfusion is not reduced in FFs and PFs in patients who have undergone ND or ND and RTX. This indicates that neck dissection and neck irradiation should not be contraindications for microvascular free flap reconstruction.

Evaluation of fibrin, cyanoacrylate, and polyurethane-based tissue adhesives in sutureless vascular anastomosis: a comparative mechanical ex vivo study.

The stability of a microvascular anastomosis is an important prerequisite for successful tissue transfer. Advances in tissue adhesives are potentially opening new avenues for their use in sutureless microsurgical anastomosis, however they have not yet gained clinical acceptance. In this ex vivo study, a novel polyurethane-based adhesive (PA) was used in sutureless anastomoses and its stability compared with that of sutureless anastomoses performed with fibrin glue (FG) and a cyanoacrylate (CA). Stability was assessed using hydrostatic (15 per group) and mechanical tests (13 per group). A total of 84 chicken femoral arteries were used in this study. The time taken to create the PA and CA anastomoses was significantly faster when compared to the FG anastomoses (P < 0.001): 1.55 ± 0.14 min and 1.39 ± 0.06 min, respectively, compared to 2.03 ± 0.35 min. Both sustained significantly higher pressures (289.3 mmHg and 292.7 mmHg, respectively) than anastomoses using FG (137.3 mmHg) (P < 0.001). CA anastomoses (0.99 N; P < 0.001) and PA anastomoses (0.38 N; P = 0.009) could both withstand significantly higher longitudinal tensile forces compared to FG anastomoses (0.10 N). Considering the background of an in vitro study, the PA and CA anastomosis techniques were shown to be similar to each other and superior to FG, due to their stability and faster handling. These findings need to be validated and confirmed in further in vivo studies.

The primary stability of two dental implant systems in low-density bone.

Primary stability in low-density bone is crucial for the long-term success of implants. Tapered implants have shown particularly favourable properties under such conditions. The aim of this study was to compare the primary stability of tapered titanium and novel cylindrical zirconia dental implant systems in low-density bone. Fifty implants (25 tapered, 25 cylindrical) were placed in the anterior maxillary bone of cadavers meeting the criteria of low-density bone. The maximum insertion (ITV) and removal (RTV) torque values were recorded, and the implant stability quotients (ISQ) determined. To establish the isolated influence of cancellous bone on primary stability, the implantation procedure was performed in standardized low-density polyurethane foam bone blocks (cancellous bone model) using the same procedure. The primary stability parameters of both implant types showed significant positive correlations with bone density (Hounsfield units) and cortical thickness. In the cadaver, the cylindrical zirconia implants showed a significantly higher mean ISQ when compared to the tapered titanium implants (50.58 vs 37.26; P < 0.001). Pearson analysis showed significant positive correlations between ITV and ISQ (P = 0.016) and between RTV and ISQ (P = 0.035) for the cylindrical zirconia implants; no such correlations were observed for the tapered titanium implants. Within the limitations of this study, the results indicate that cylindrical zirconia implants represent a comparable viable treatment option to tapered titanium implants in terms of primary implant stability in low-density human bone.