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Purpose: To report our experience with patient specific implants for one-step orbit reconstruction following hyperostotic SWM removal and to describe the evolution of the technique through three surgical cases. Methods: Three cases of one-step SWM removal and orbit reconstruction are described. All cases are given consecutively to describe the evolution of the technique. Hyperostotic bone resection was facilitated by electromagnetic navigation and cutting guides (templates). Based on a 3D model, silicone molds were made using CAD/CAM. Then PMMA implant was fabricated from these molds. The implant was adjusted and fixed to the cranium with titanium screws after tumor removal. Results: Following steps of the procedure changed over these series: hyperostotic bone resection, implant thickness control, implant overlay features, anatomic adjustments, implant fixation. The proptosis resolved in all cases. In one patient the progressive visual acuity deterioration was recognized during the follow-up. No oculomotor disturbances and no tumor regrowth were found at the follow-up. Conclusion: CAD/CAM technologies enable creation of implants of any size and configuration, and thereby, to increase the extent of bony resection and lower the risk of tumor progression. The procedure is performed in one step which decreases the risk of postoperative morbidity.

Aim – to measure and compare the vertical and horizontal angles of attack on different intracranial surgical targets provided by the transzygomatic, modified orbitozygomatic and classic two-piece orbitozygomatic approaches, to determine the most optimal approaches to different surgical targets. Material and methods. The study was conducted on 8 sides of en bloc specimens of human head and neck. The marking was performed with BrainLAB Kolibri navigational station (Germany) to highlight the surgical landmarks and measure the angles. The dissection was started macroscopically with standard instruments and photographic fixation of every stage of the approach. The craniotomy was performed with Stryker high speed drill (USA). After that, the microscopic stage was carried out with the ZEISS OPMI Vario/S88 surgical microscope (Germany). On each side, the following steps were completed: soft tissues dissection, cutting the zygomatic arch, fronto-temporal craniotomy, orbitozygomatic osteotomy, opening of the dura mater and dissection of structures of the cranial base, measurement of angles of attack with their apex located on skull base structures Results. The angles of attack on different intracranial surgical targets were measured and compared for two-piece orbitozygomatic, modified orbitozygomatic and transzygomatic approaches. Conclusion. The two-piece orbitozygomatic craniotomy is the most universal and optimal to approach the basilar artery bifurcation and lesions located in both anterior and middle cranial fossae. However, to minimize the surgical trauma and the risks of complications when exposing exclusively anterior cranial fossa, the modified orbitozygomatic approach is more adequate. When the lesion is small and located exclusively in middle cranial fossa, performing the transzygomatic approach is recommended.

Background: Complex anterior skull base defects produced by resection of mass lesions vary in size and configuration and may be extensive. We analyzed the largest single-center series of midline craniofacial lesions extending intra- and extracranially. The study aims at the development of a predictive model for preoperative measurement of the risk of the postoperative cerebrospinal fluid (CSF) leak based on patients' characteristics and surgical plans. Methods: 166 male and 149 female patients with mean age 40,5 years (1 year and – 81 years) operated for benign and tumor-like midline craniofacial mass lesions were retrospectively analyzed using logistic regression method (Ridge regression algorithm was selected). The overall CSF leak rate was 9.6%. The ROSE algorithm and ‘glmnet’ software suite in R were used to overcome the cohort's disbalance and avoid overtraining the model. Results: The most influential modifiable negative predictor of the postoperative CSF leak was the use of extracranial and combined approaches. Use of transbasal approaches, gross total resection, utilization of one or two vascularized flaps for skull base reconstruction were the foremost modifiable predictors of a good outcome. Criterium of elevated risk was established at 50% with a specificity of the model as high as 0.83. Conclusions: The performed study has allowed for identifying the most significant predictors of postoperative CSF leak and developing an effective formula to estimate the risk of this complication using data known for each patient. We believe that the suggested web-based online calculator can be helpful for decision making support in off-pattern clinical situations.